JPH11166168A - Method for producing acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive tape - Google Patents

Abstract

(57) [Abstract] (Modified) [Problem] An environmentally friendly acrylic-based cationic photopolymerizable pressure-sensitive adhesive composition capable of producing a high-performance pressure-sensitive adhesive tape by a production method with low energy consumption, and its adhesiveness The present invention provides a method for producing a high-performance pressure-sensitive adhesive tape obtained by subjecting an agent composition to photocationic polymerization. SOLUTION: An acrylic pressure-sensitive adhesive composition containing a photocationic catalyst with respect to an acrylic oligomer obtained by polymerizing a monomer component containing the following components (a) to (e). Component (a): Non-3 having an alkyl group having 2 to 18 carbon atoms
(Meth) acrylic acid ester (b) component of a secondary alcohol: having an unsaturated double bond copolymerizable with the above component (a) in one molecule, and having a photocationically polymerizable functional group and a hydroxyl group. Vinyl compound (c) component not to be used: a vinyl compound having a photocationically polymerizable functional group in one molecule and an unsaturated double bond copolymerizable with the above component (a) component (d) component: a hydroxyl group in one molecule And a vinyl compound having an unsaturated double bond copolymerizable with the above component (a), and a component (e): a radical chain transfer agent

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acrylic photocationically polymerizable pressure-sensitive adhesive composition and a method for producing a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive products such as pressure-sensitive adhesive tapes, pressure-sensitive adhesive sheets, and pressure-sensitive adhesive labels have been used for various purposes as auxiliary materials for packaging, assembling industrial products, and processing industrial products, taking advantage of the simplicity of their operations. Widely used. In general, this type of pressure-sensitive adhesive product has been manufactured by a so-called solvent method in which a solvent-type pressure-sensitive adhesive obtained by dissolving a polymer composition in an organic solvent is applied to a substrate and dried. In response to the recent rise in social needs for environmental improvement and the like, there is a strong demand for an alternative to a solventless manufacturing method (hereinafter simply referred to as a "solventless method").

Examples of the solvent-free method include an aqueous method using an aqueous adhesive such as an acrylic resin-based emulsion adhesive, a natural or synthetic rubber-based latex adhesive, a styrene-butadiene-styrene block copolymer, and styrene. -Hot-melt method using a hot-melt block polymer such as isoprene-styrene block copolymer, or an acrylic monomer is applied to a substrate and then polymerized by irradiation with light such as ultraviolet light to form an adhesive. The photopolymerization method and the like to be used have been studied and are being put to practical use.

[0004] However, at present, such various solvent-free systems are not completely indispensable, but have their own problems.

[0005] That is, in the case of the water-based system, the water-based pressure-sensitive adhesive does not contain an organic solvent and thus has the advantage of not generating a carbon dioxide gas source. Resources), which has a large indirect effect on the environment, and in general, water-based adhesives have insufficient water resistance because they are in a dispersed form with surfactants and emulsifiers.
There is a problem that the use and the field of use of the obtained pressure-sensitive adhesive product are limited.

In the case of the hot-melt method, a heat-meltable polymer is used as a main component of the pressure-sensitive adhesive, so that the heat resistance is insufficient, and the applications and fields of use of the resulting pressure-sensitive adhesive products are limited. There is a point. Various attempts have been made to address the above problems, for example, PSTC
Proceedings, p175-187 (199
In 5), “After grafting a photo-crosslinkable functional group to a hot-melt acrylic polymer and applying heat-melt coating on a substrate,
UV crosslinking method "has been proposed. However, the hot-melt pressure-sensitive adhesive obtained by the method according to the above proposal has a problem that the cross-linking density is low, so that high pressure-sensitive adhesive strength cannot be exhibited.

Further, in the case of the photopolymerization method, since the monomer is applied to the substrate and then directly photopolymerized, waste such as a solvent which is finally discarded and becomes a carbon dioxide gas source is not used, and the photopolymerization method is not used. It is environmentally favorable because the electrical energy consumed for the polymerization is small. However, it is necessary to slow down the polymerization rate in order to obtain a high molecular weight polymer in order to improve the performance of the resulting pressure-sensitive adhesive, which makes it difficult to obtain high productivity and the effect of polymerization inhibition due to oxygen in the atmosphere. As a result, there is a problem that the amount of the residual monomer increases, the performance of the obtained pressure-sensitive adhesive decreases, and the odor increases.

To address the above problems, for example, Ad
hesive Age, November (1995)
Proposes "a photocationically polymerizable pressure-sensitive adhesive containing an ethylene-butylene oligomer having an epoxy group and a hydroxyl group in one molecule as a main component". However, although the pressure-sensitive adhesive according to the above proposal can obtain a pressure-sensitive adhesive having low selectivity to an adherend without a solvent, the ethylene-butylene oligomer polymer itself has elastic properties, and thus is excellent. It is necessary to add a large amount of tackifying resin in order to impart the tackiness, and as a result, there is a problem that the heat resistance of the obtained adhesive is insufficient, and ethylene-butylene oligomer is a main component. Therefore, the degree of freedom to change the composition of the polymer is limited as compared with the case where an acrylic monomer is used as a main component, and therefore, various properties requiring various properties such as solvent resistance, light resistance, and ozone resistance are required. There is a problem that it is difficult to design an adhesive for the purpose.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a high-performance adhesive tape which does not require the use of an organic solvent and which consumes less energy in the process. An object of the present invention is to provide an environmentally friendly acrylic cationic photopolymerizable pressure-sensitive adhesive composition that can be produced, and a method for producing a high-performance pressure-sensitive adhesive tape obtained by photocationically polymerizing the pressure-sensitive adhesive composition. .

[0010]

The acrylic pressure-sensitive adhesive composition according to the invention described in claim 1 (hereinafter referred to as "first invention") comprises 60 to 100% by weight of the following component (a) and the following (b): ) Component 0.1 to 40% by weight and component (c1) 0.1 to 10% by weight, component (d) 0.1 to 10% by weight and component (e) 0.001 to 2% by weight 100 parts by weight of an acrylic oligomer having a weight average molecular weight in terms of polystyrene of 3000 to 100,000 obtained by polymerizing the monomer component
-5 parts by weight. Component (a): Non-3 having an alkyl group having 2 to 18 carbon atoms
(Meth) acrylic acid ester of a secondary alcohol (b) Component: having an unsaturated double bond copolymerizable with the above component (a) in one molecule, and having a photocationically polymerizable functional group and a hydroxyl group. (C1) Component: a vinyl compound having a photocationically polymerizable functional group and an unsaturated double bond copolymerizable with the component (a) in one molecule. (D) Component: a hydroxyl group in one molecule. And a vinyl compound having an unsaturated double bond copolymerizable with the above component (a). Component (e): a radical chain transfer agent

Further, the invention according to claim 2 (hereinafter referred to as “second
Inventive), the acrylic pressure-sensitive adhesive composition comprises 60 to 100% by weight of the following component (a) and 0.1% of the following component (b).
-40% by weight, the following component (c2): 0.1-10% by weight,
The weight average molecular weight in terms of polystyrene obtained by polymerizing a monomer component containing the following component (d) 0.1 to 10% by weight and the following component (e) 0.001 to 2% by weight is 300.
0-100,000 acrylic oligomer (A) 100
The following component (a) is 60 to 100% by weight, the following component (b) is 0.1 to 40% by weight, and the following component (d) is 0.
Acrylic oligomer (B) having a polystyrene equivalent weight average molecular weight of 3,000 to 100,000, obtained by polymerizing a monomer component containing 1 to 10% by weight and the following (e) component 0.001 to 2% by weight, 1 to 200% by weight And 0.05 to 5 parts by weight of a photocationic catalyst. Component (a): Non-3 having an alkyl group having 2 to 18 carbon atoms
(Meth) acrylic acid ester of a secondary alcohol (b) Component: having an unsaturated double bond copolymerizable with the above component (a) in one molecule, and having a photocationically polymerizable functional group and a hydroxyl group. (C2) component: a vinyl compound having a photocationically polymerizable functional group and an unsaturated double bond copolymerizable with component (a) in one molecule, or photocationic polymerization in one molecule Compound having an acidic functional group, a hydroxyl group and an unsaturated double bond copolymerizable with the above component (a) (d) component: a hydroxyl group and an unsaturated dihydric copolymerizable with the above component (a) in one molecule Vinyl compound having heavy bond (e) component: radical chain transfer agent

Further, the invention according to claim 3 (hereinafter referred to as "the invention")
The method for producing an adhesive tape according to “third invention”)
Applying the acrylic pressure-sensitive adhesive composition according to the first invention or the second invention to at least one surface of a substrate, and performing light irradiation,
The pressure-sensitive adhesive composition is photo-cationically polymerized.

[0013] Among the monomer components used for obtaining the acrylic oligomer constituting the acrylic pressure-sensitive adhesive composition according to the first invention or the second invention, (a) component
It contains 60 to 100% by weight of a (meth) acrylate of a non-tertiary alcohol having an alkyl group having 2 to 18 carbon atoms, preferably 4 to 12 carbon atoms. Here, “(meth) acryl” means “acryl” or “methacryl”.

The component (a) is not particularly restricted but includes, for example, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate. ,
Examples thereof include isononyl (meth) acrylate and isomyristyl (meth) acrylate, and one or more of these are preferably used.

When the carbon number of the alkyl group of the non-tertiary alcohol constituting the component (a) is out of the range of 2 to 18, the resulting pressure-sensitive adhesive composition has insufficient tackiness and cohesive strength. It is not preferable because it may occur.

On the other hand, if the content of the component (a) in the monomer component is less than 60% by weight, the resulting pressure-sensitive adhesive composition may have insufficient tackiness, cohesive strength and the like, which is not preferable. .

In the monomer component used to obtain the acrylic oligomer constituting the acrylic pressure-sensitive adhesive composition according to the first or second invention, (b) component
In one molecule, 0.1 to 40% by weight of a vinyl compound having an unsaturated double bond copolymerizable with the component (a) and not having a photocationically polymerizable functional group or a hydroxyl group is contained. You.

The above-mentioned component (b) is a pressure-sensitive adhesive which does not have reactivity with the photocationic polymerizable functional group or hydroxyl group contained in the component (c1) or the component (c2) described later. It is preferable in terms of adhesiveness and storage stability of the composition. For example, a vinyl monomer such as (meth) acrylic acid is a photocationically polymerizable functional group grafted to an acrylic oligomer in the adhesive composition. Or, it is not preferable because it reacts with a hydroxyl group with time to cause a decrease in tackiness and storage stability.

The component (b) is not particularly restricted but includes, for example, (meth) acrylonitrile,
Examples thereof include N-vinylpyrrolidone, acrylamide, isobornyl (meth) acrylate, acryloylmorpholine, and alkoxyalkyl acrylate, and one or more of these are suitably used.

As the component (b), one or more so-called macromonomers (macromers) composed of polystyrene, polymethyl methacrylate, polyacrylonitrile or the like having a radically polymerizable unsaturated double bond at the terminal are used. May be.

If the content of the component (b) in the monomer component is less than 0.1% by weight, the resulting acrylic pressure-sensitive adhesive composition may have insufficient cohesive strength, which is not preferable. If the content of the component (b) exceeds 40% by weight, the resulting pressure-sensitive adhesive composition may have insufficient tackiness.

The monomer component used for obtaining the acrylic oligomer constituting the acrylic pressure-sensitive adhesive composition according to the first invention includes, as a component (c1), a photocationically polymerizable functional group in one molecule and (A) Vinyl compound having unsaturated double bond copolymerizable with component (a)
0% by weight is contained.

The vinyl compound having a photocationically polymerizable functional group and an unsaturated double bond copolymerizable with the component (a) in one molecule as the component (c1) is not particularly limited. Although not available, for example, glycidyl (meth) acrylate, for example, a (meth) acrylate having an alicyclic epoxy group, a (meth) acrylate having an oxetanyl group, such as “Cyclomer” (trade name, manufactured by Daicel Chemical Industries, Ltd.), and the like. One or more of these are suitably used.

When the content of the component (c1) in the monomer component is less than 0.1% by weight, a partial cross-linking reaction between the acrylic polymer and the photocationically polymerizable functional group is obtained. On the contrary, if the content of the component (c1) exceeds 10% by weight, the crosslink density of the acrylic polymer becomes too high, which is not preferable. It is not preferable because the adhesiveness of the adhesive composition may be insufficient.

In the monomer component used to obtain the acrylic oligomer (A) constituting the acrylic pressure-sensitive adhesive composition according to the second invention, the component (c2) is a cationic photopolymerizable functional group in one molecule. A vinyl compound having a group and an unsaturated double bond copolymerizable with the component (a), or a photocationically polymerizable functional group, a hydroxyl group and an unsaturated copolymerizable with the component (a) in one molecule. It contains 0.1 to 10% by weight of a vinyl compound having a double bond.

The vinyl compound having a photocationically polymerizable functional group and an unsaturated double bond copolymerizable with the component (a) in one molecule as the component (c2) is not particularly limited. Although not available, for example, glycidyl (meth) acrylate, for example, a (meth) acrylate having an alicyclic epoxy group, a (meth) acrylate having an oxetanyl group, such as “Cyclomer” (trade name, manufactured by Daicel Chemical Industries, Ltd.), and the like. One or more of these are suitably used.

The vinyl compound having a cationically polymerizable functional group, a hydroxyl group and an unsaturated double bond copolymerizable with the component (a) in one molecule as the component (c2) is not particularly limited. However, examples thereof include hydroxyglycidyl (meth) acrylate, hydroxy (meth) acrylate having an alicyclic epoxy group, hydroxy (meth) acrylate having an oxetanyl group, and one or two of these. The above is preferably used.

As the component (c2), a vinyl compound having a photocationically polymerizable functional group in one molecule and an unsaturated double bond copolymerizable with the component (a), or a photocationic polymerization in one molecule The vinyl compound having an unsaturated double bond copolymerizable with the acidic functional group, hydroxyl group and component (a) may be used alone or in combination.

When the content of the component (c2) in the monomer component is less than 0.1% by weight, the crosslinking reaction between the acrylic polymer and the photocationically polymerizable functional group or hydroxyl group becomes partial, On the contrary, when the content of the component (c2) exceeds 10% by weight, the crosslink density of the acrylic polymer becomes too high, which is not preferable. This is not preferred because the resulting adhesive composition may have insufficient tackiness.

In the monomer component for obtaining the acrylic oligomer constituting the acrylic pressure-sensitive adhesive composition according to the first or second invention, the component (d) includes a hydroxyl group in one molecule and the component (a). And 0.1 to 10% by weight of a vinyl compound having an unsaturated double bond copolymerizable with the vinyl compound.

The component (d) is not particularly restricted but includes, for example, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate,
For example, caprolactone-modified acrylates such as the trade name “Placcel” series (manufactured by Daicel Chemical Industries, Ltd.) are exemplified, and one or more of these are preferably used.

By including the component (d) in the monomer component, a chain transfer reaction and a termination reaction at the time of photopolymerization of the obtained acrylic pressure-sensitive adhesive composition are more accurately performed, and as a result, finally, The resulting pressure-sensitive adhesive layer has higher performance.

If the content of the component (d) in the monomer component is less than 0.1% by weight, the above-mentioned effect due to the addition of the component (d) may not be sufficiently obtained. Conversely, if the content of the component (d) exceeds 10% by weight, the photopolymerization reaction of the obtained acrylic pressure-sensitive adhesive composition may not sufficiently proceed, which is not preferable.

[0034] Among the monomer components used to obtain the acrylic oligomer constituting the acrylic pressure-sensitive adhesive composition according to the first or second invention, the component (e) includes:
It contains 0.001 to 2% by weight of a radical chain transfer agent.

The radical chain transfer agent as the component (e) is not particularly limited.
Mercaptans such as dodecyl mercaptan; α-methylstyrene dimers; halides such as carbon tetrachloride and chloroform; mercaptoethyl alcohol, mercaptoisopropyl alcohol, hydroquinone, and a rosin ester having a hydroxyl group and a conjugated double bond in one molecule. And the like. A radical chain transfer agent having a hydroxyl group in one molecule such as a class is exemplified, and one or more of these are suitably used.

By including a radical chain transfer agent as the above-mentioned component (e) in the monomer component, the molecular weight of the obtained acrylic polymer can be controlled so as to be in an appropriate range, and the adhesion of the obtained acrylic polymer can be controlled. The balance between force and cohesive force can be further improved.

If the content of the component (e) in the monomer component is less than 0.001% by weight, the obtained acrylic polymer has a too high molecular weight, and has a high viscosity.
On the contrary, when the content of the component (e) exceeds 2% by weight, the obtained acrylic polymer has too low a molecular weight, and a high degree of adhesion and cohesion is obtained. It is not preferable because a good balance may not be obtained.

The method for producing the acrylic oligomer (hereinafter simply referred to as “oligomer”) constituting the acrylic pressure-sensitive adhesive composition according to the first or second invention is not special, and the above-mentioned monomer component is used. A desired oligomer may be obtained by a conventional solution polymerization method, emulsion polymerization method, dispersion polymerization method, bulk polymerization method, photopolymerization method or the like.

The oligomer used in the first invention, or
The oligomer (A) or (B) used in the second invention
Means that the weight average molecular weight in terms of polystyrene is 3000 to 10
0000. In addition, the polystyrene-equivalent weight average molecular weight referred to in the present invention means a polystyrene-equivalent weight average molecular weight measured by a GPC method.

The oligomer has a weight average molecular weight in terms of polystyrene (hereinafter simply referred to as “weight average molecular weight”) of 300.
If it is less than 0, the resulting pressure-sensitive adhesive composition may have too high a crosslinking density, and may have insufficient tackiness.

Conversely, when the weight average molecular weight of the oligomer is 100
If it exceeds 000, the resulting pressure-sensitive adhesive composition will have an excessively high crosslinking density and insufficient tackiness if the ratio of photocationically polymerizable functional groups such as epoxy groups in one molecule is high. When the ratio of the photocationically polymerizable functional group in one molecule is low, the probability of contact between the functional groups decreases, so that unreacted oligomers are likely to remain and the cohesive force is reduced. Is not preferred.

The pressure-sensitive adhesive composition obtained by using an oligomer having a weight-average molecular weight of more than 100,000 must be melted at a high temperature in order to obtain a coatable viscosity. It is not preferable because a significant increase in viscosity or gelation due to a thermal reaction of the functional group may occur in the coating apparatus.

The type of the above oligomer is not particularly limited, but for example, an epoxy group,
A cationically polymerizable oligomer having a photocationically polymerizable functional group such as an oxetanyl group or the like, having a photocationically polymerizable functional group in the molecule and participating in a chain transfer reaction or termination reaction in a cationic polymerization such as a hydroxyl group; A cationically polymerizable mobile oligomer having a functional group,
A cation-transfer oligomer having no functional group capable of participating in a chain transfer reaction or a termination reaction in cation polymerization such as a hydroxyl group, which does not have a photocationically polymerizable functional group. The above is preferably used.

The oligomer used in the first invention corresponds to the above-mentioned cationically polymerizable oligomer.

The oligomer (A) used in the second invention corresponds to the above-mentioned cationic polymerizable oligomer and / or the above-mentioned cationic polymerizable oligomer, and the oligomer (B) used in the second invention is the above-mentioned cationic polymerizable oligomer. Functional oligomer.

The above-mentioned cationically polymerizable oligomers or cationically polymerizable oligomers may be used alone or in combination.

The above-mentioned cation-migrating oligomer may be used in combination with a cation-polymerizable oligomer and / or a cation-polymerizable oligomer, but the cation-migrating oligomer is not used alone.

The above-mentioned cationically polymerizable oligomer, cationically polymerizable oligomer or cationically movable oligomer may have the same composition or different compositions.

Accordingly, by preparing only a few types of oligomers, it becomes possible to design acrylic pressure-sensitive adhesive compositions having different crosslink densities and different glass transition temperatures, etc., and to prepare acrylic pressure-sensitive adhesive compositions suitable for various uses. The performance of the pressure-sensitive adhesive composition can be easily controlled.

The acrylic pressure-sensitive adhesive composition according to the first invention is characterized in that a photocationic catalyst of 0.05 part per 100 parts by weight of the acrylic oligomer which is the cationic polymerizable oligomer.
-5 parts by weight.

The acrylic pressure-sensitive adhesive composition according to the second aspect of the present invention is characterized in that the cation-polymerizable oligomer and / or the cation-polymerizable oligomer (A), 100 parts by weight, are mixed with the cation-polymerizable oligomer. From 1 to 200 parts by weight of an acrylic oligomer (B) and 0.05 to 5 parts by weight of a photocationic catalyst.

The photocationic catalyst contained in the acrylic pressure-sensitive adhesive composition according to the first or second invention includes a photocationically polymerizable functional group such as an epoxy group upon irradiation with light having a wavelength of at least 300 to 370 nm. Any compound may be used as long as it is a compound that can initiate the polymerization of, but is not particularly limited to, for example, a photopolymerization initiating compound and the like are preferably used.

The photopolymerization initiating compound is not particularly restricted but includes, for example, iron-allene complex compounds, aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts and pyridinium salts. ,
One or more of these are preferably used.

Specific examples of the photopolymerization initiating compound are not particularly limited. For example, trade names “IRGACURE 261” (manufactured by Ciba-Geigy), trade names “Optomer SP-150”, “Optomer SP-”
151 "," OPTMER SP-170 "," OPTMER SP-171 "(all manufactured by Asahi Denka Kogyo KK), trade name" U
VE-1014 "(manufactured by General Electronics),
Product name “CD-1012” (manufactured by Sartomer), product name “Sun-Aid SI-60L”, “Sun-Aid SI-80”
L "," San Aid SI-100L "(manufactured by Sanshin Chemical Industry Co., Ltd.), trade names" CI-2064 "," CI-24 "
81 "," CI-2624 "," CI-2639 "(all manufactured by Nippon Soda Co., Ltd.), trade name" RHODORSIL P
commercially available products such as "photoinitiator 2074" (manufactured by Rhone Poulin), and one or more of these are suitably used.

In the acrylic pressure-sensitive adhesive composition according to the first invention, if the content of the photocationic catalyst is less than 0.05 part by weight based on 100 parts by weight of the acrylic oligomer, the rate of radical polymerization upon light irradiation is reduced. Conversely, if the content of the photocationic catalyst is more than 5 parts by weight with respect to 100 parts by weight of the oligomer, it is not preferable because curing inside the pressure-sensitive adhesive layer may be insufficient due to light absorption.

In the acrylic pressure-sensitive adhesive composition according to the second aspect of the invention, if the content of the acrylic oligomer (B) is less than 1 part by weight based on 100 parts by weight of the acrylic oligomer (A), the content during the photoradical polymerization is reduced. When the content of the acrylic oligomer (B) exceeds 200 parts by weight, the photoradical polymerization is not sufficiently performed because the effect of performing the chain transfer reaction and the termination reaction more accurately may not be sufficiently obtained. It is not preferable because it may not progress.

Further, in the acrylic pressure-sensitive adhesive composition according to the second invention, when the content of the photocationic catalyst is less than 0.05 part by weight based on 100 parts by weight of the acrylic oligomer (A), radical polymerization during light irradiation is performed. On the contrary, when the content of the photocationic catalyst with respect to 100 parts by weight of the oligomer (A) exceeds 5 parts by weight, the curing inside the pressure-sensitive adhesive layer becomes insufficient due to light absorption. It is not preferable because it may occur.

The acrylic pressure-sensitive adhesive composition according to the first or second invention may contain, if necessary, a tackifying resin, a thickener, a thixotropic agent, a bulking agent, and a filler within a range not to impair the achievement of the object of the present invention. One or more of various additives such as agents, softeners, plasticizers, surfactants, stabilizers, antioxidants, and colorants may be contained.

The tackifying resin is preferably a resin having no reactivity with a photocationically polymerizable functional group such as an epoxy group, and is not particularly limited. Examples thereof include rosin and disproportionated rosin. rosin resins, modified rosin resins such as rosin esters and hydrogenated rosin esters, terpene resins, modified terpene resins, terpene phenol resins, hydrogenated terpene phenol resin, aromatic modified terpene resins, C ₅ petroleum resins, C _Ninth petroleum resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic hydrocarbon resin, coumarone indene resin, etc., and one or more of these are preferably used. Among them, one or more of disproportionated rosin, a hydrogenated terpene phenol resin, an alicyclic hydrocarbon resin and the like having a large initial tackiness improving effect are more preferable. Used for

Examples of the thickener include, but are not particularly limited to, elastomers such as acrylic rubber, epichlorohydrin rubber, isoprene rubber, and butyl rubber. One or more of these are preferably used. Can be

The thixotropic agent is not particularly restricted but includes, for example, colloidal silica, polyvinylpyrrolidone and the like.
More than one species is preferably used.

The extender is not particularly restricted but includes, for example, calcium carbonate, titanium oxide, clay, talc and the like, and one or more of these are preferably used.

Examples of the filler include inorganic hollow bodies such as glass balloons, alumina balloons and ceramic balloons; organic hollow bodies such as vinylidene chloride balloons and acrylic balloons; organic spherical bodies such as nylon beads, acrylic beads and silicone beads; Single fibers such as rayon and nylon are exemplified, and one or more of these are suitably used.

Next, in the method for producing a pressure-sensitive adhesive tape according to the third invention, the acrylic pressure-sensitive adhesive composition according to the first invention or the second invention is applied to at least one surface of a substrate, and is irradiated with light. It is characterized in that the composition is subjected to photocationic polymerization.

The substrate may be one generally used in the production of pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets, and is not particularly limited. Examples thereof include a polyethylene terephthalate (PET) film and a soft vinyl chloride resin sheet. Etc. synthetic resin film or sheet, cellophane, cloth,
Non-woven fabrics, metal foils and the like can be mentioned, and are preferably used.

According to the third invention, the acrylic pressure-sensitive adhesive composition applied on the base material is cationically polymerized by light irradiation without heating, thereby forming a pressure-sensitive adhesive layer. It can be suitably applied to a substrate.

Further, a pressure-sensitive adhesive tape may be manufactured by using a substrate having releasability such as a peelable film, and finally, the substrate may be removed to obtain a so-called non-support type pressure-sensitive adhesive tape.

Further, the adhesive tape may be a single-sided adhesive tape or a double-sided adhesive tape.

According to the third aspect of the invention, when producing a double-sided tape, the acrylic pressure-sensitive adhesive composition can be simultaneously applied to both sides of the base material and simultaneously irradiated with light to form a pressure-sensitive adhesive layer. As in the case of using a conventional solvent-based pressure-sensitive adhesive composition, for example, a pressure-sensitive adhesive layer is first provided on a peelable film, and then it is not necessary to take a complicated step of transferring onto a substrate. This greatly simplifies the process and eliminates the need for a peelable film, so that the cost can be reduced.

The coating thickness of the acrylic pressure-sensitive adhesive composition on the substrate surface may be appropriately set according to the use and purpose of use of the pressure-sensitive adhesive tape, and is not particularly limited.
The thickness is preferably 10 to 1000 μm per one side of the substrate.

The acrylic pressure-sensitive adhesive composition applied to the surface of the base material is cationically polymerized by irradiation with light to form a pressure-sensitive adhesive layer, thereby forming a pressure-sensitive adhesive tape.

As the type of lamp used for the light irradiation, a lamp having a light emission distribution at a light wavelength of 400 nm or less is suitably used, and is not particularly limited. Examples of the lamp include a low-pressure mercury lamp, a medium-pressure mercury lamp, and a high-pressure mercury lamp. Mercury lamps, ultra-high pressure mercury lamps, microwave-excited mercury lamps, chemical lamps, black light lamps, metal halide lamps, and the like are preferably used.

Among the above-mentioned various lamps, short-wavelength light or acryl which can efficiently emit light in the active wavelength region of the photocationic catalyst and reduce the viscoelastic properties of the obtained polymer by crosslinking. A chemical lamp that does not emit much long-wavelength light, such as heating and evaporating the components in the adhesive composition, is more preferably used.

The light irradiation intensity of the acrylic pressure-sensitive adhesive composition is a main factor that determines the degree of polymerization of the obtained polymer, and may be appropriately set according to the performance required for the target product. Light wavelength range effective for catalyst activation (depending on the type of photocationic catalyst, usually 340
The light irradiation intensity is preferably 0.1 to 100 mW / cm ² .

When the light irradiation intensity is less than 0.1 mW / cm ² , the cationic polymerization does not proceed sufficiently and the polymerization time becomes longer. On the contrary, when the light irradiation intensity exceeds 100 mW / cm ² , the resulting adhesive The cohesive force of the agent layer becomes insufficient.

[0076]

The acrylic pressure-sensitive adhesive composition according to the first or second invention has a (meth) acrylate ester as a main skeleton,
Since it is an oligomer-type pressure-sensitive adhesive composition having photocationic polymerizability, after being applied to a substrate surface in a solvent-free state, a pressure-sensitive adhesive layer is formed by light irradiation with a small energy consumption,
Suitable for easily obtaining high-performance adhesive tape.

Further, since it is a solvent-free oligomer type pressure-sensitive adhesive composition, there is almost no volatilization of a solvent, a monomer and the like, and there is almost no adverse effect on the environment. Further, since the oligomer-type pressure-sensitive adhesive composition is converted into a pressure-sensitive adhesive by photocationic polymerization, the polymerization is hardly affected by oxygen in the air or dissolved oxygen in the pressure-sensitive adhesive composition. Suitable for obtaining high performance odor and high performance adhesive tape.

Further, in the method for producing a pressure-sensitive adhesive tape according to the third invention, the oligomer-type pressure-sensitive adhesive composition according to the first invention or the second invention is applied to at least one surface of a substrate, and is irradiated with light. Since it is carried out by photocationic polymerization of the composition, a high-performance adhesive tape can be obtained with high productivity without adversely affecting the environment.

[0079]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight”.

(Example 1)

( 1) Polymerization of acrylic oligomer 100 parts of 2-ethylhexyl acrylate as component (a) and N-vinylpyrrolidone 3 as component (b)
0 parts, glycidyl methacrylate 1 as the component (c1)
Parts, (d) 0.2 parts of hydroxyethyl methacrylate, (e) 0.3 parts of mercaptoethyl alcohol, and 0.1 part of benzoyldimethyl ketal as a photoradical polymerization initiator. The dissolved oxygen in the mixture was removed by purging the gas to obtain a monomer component. Next, the monomer component obtained above was placed on a PET film having a peelable surface with a thickness of 1 m.
m, and then covered with a PET film having a peelable surface. Then the covered P
Ultraviolet irradiation was performed through an ET film using a chemical lamp at a light irradiation intensity of ² mW / cm ² , and the monomer component was subjected to photoradical polymerization to obtain an acrylic oligomer. The weight average molecular weight of the obtained acrylic oligomer in terms of polystyrene measured by the GPC method was 100,000.
Met.

( 2) Preparation of Acrylic Pressure-Sensitive Adhesive Composition To 100 parts of the acrylic oligomer obtained above,
Trade name "OPTMER SP-17" as a photocationic catalyst
0 "(manufactured by Asahi Denka Kogyo KK) was added and uniformly stirred and mixed to obtain an oligomer type acrylic pressure-sensitive adhesive composition.

( 3) Preparation of pressure-sensitive adhesive tape After the oligomer-type acrylic pressure-sensitive adhesive composition obtained above was applied on a PET film (substrate) so as to have a thickness of 50 μm, using a high-pressure mercury lamp, Light irradiation intensity 10
UV irradiation was performed under the conditions of 0 mW / cm ² and light irradiation time of 20 seconds, and the acrylic pressure-sensitive adhesive composition was subjected to photocationic polymerization to form a pressure-sensitive adhesive layer, thereby obtaining a single-sided pressure-sensitive adhesive tape having a PET film as a base material. .

( 4) Evaluation The pressure-sensitive adhesive tape obtained above was used for a width of 25 mm and a length of 50 mm.
After being cut into stripes, the sample was stuck on a stainless steel plate and pressure-bonded using a 2 kg rubber roller to prepare a test piece for measurement. Next, after leaving the test piece for measurement obtained above in an atmosphere of 23 ° C. and 55% RH for 24 hours,
Under the same atmosphere, a 180-degree square peeling test was performed at a peeling speed of 300 mm / min, and the maximum peeling force at that time was determined and defined as a peeling strength (kgf / 25 mm). As a result, the peel strength was 1.8 kgf / 25 mm.

(Example 2) In a 2-liter separable flask, 400 parts of n-butyl acrylate as component (a), 100 parts of N-vinylpyrrolidone as component (b), and glycidyl methacrylate as component (c1) 20 parts, 1 part of hydroxyethyl methacrylate as a component (d), 0.2 parts of mercaptoethyl alcohol as a component (e), 0.3 parts of azobisisobutyronitrile (AIBN) as a radical polymerization initiator, and acetic acid as an organic solvent 500 parts of ethyl was charged, and normal solution radical polymerization was performed at 60 ° C. for 7 hours to obtain an acrylic oligomer solution. Next, using an evaporator, ethyl acetate in the oligomer solution obtained above was removed to obtain an acrylic oligomer. The weight average molecular weight of the obtained acrylic oligomer in terms of polystyrene measured by the GPC method was 80,000.

Then, based on 100 parts of the acrylic oligomer obtained above, 20 parts of trade name "Super Ester A-100" (manufactured by Arakawa Chemical Industries) as a tackifier resin and "Optomer SP" as a photocationic catalyst. -1
70 "(manufactured by Asahi Denka Kogyo KK) and uniformly stirred and mixed to obtain an oligomer type acrylic pressure-sensitive adhesive composition.

Using the oligomer-type acrylic pressure-sensitive adhesive composition obtained above, a single-sided pressure-sensitive adhesive tape having a PET film as a base material was obtained in the same manner as in Example 1. Next, using the pressure-sensitive adhesive tape obtained above, a 180-degree angle peel test was performed in the same manner as in Example 1 to determine the peel strength. The peel strength was 1.5 kgf / 25 mm.

Example 3 An acrylic oligomer was obtained in the same manner as in Example 1 except that 0.2 part of dodecyl mercaptan was used as the component (e) instead of 0.3 part of mercaptoethyl alcohol. Was. The weight average molecular weight of the obtained acrylic oligomer in terms of polystyrene measured by a GPC method was 90000.

Using the acrylic oligomer obtained above, a single-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive composition and a PET film as substrates was obtained in the same manner as in Example 1.
Next, using the pressure-sensitive adhesive tape obtained above, a 180-degree angle peel test was performed in the same manner as in Example 1 to determine the peel strength. The peel strength was 0.8 kgf / 25 mm.

Comparative Example 1 An acrylic oligomer was obtained in the same manner as in Example 1, except that the monomer component did not contain the component (e), mercaptoethyl alcohol. The weight average molecular weight of the obtained acrylic oligomer in terms of polystyrene measured by GPC was 8,000.
00 or more.

Using the acrylic oligomer obtained above, an acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1. However, since the viscosity of the oligomer was too high, the photocationic catalyst “Optomer SP- 170 "could not be added. An attempt was made to produce an adhesive tape in the same manner as in Example 1. However, the adhesive tape was not melted even when heated to 180 ° C., and could not be applied on a PET film (substrate).

[0092]

As described above, the acrylic pressure-sensitive adhesive composition according to the first or second invention is an oligomer-type pressure-sensitive adhesive composition having photocationic polymerizability. No impact on the environment.

Further, the pressure-sensitive adhesive layer can be easily formed by cationic polymerization which is hardly inhibited by polymerization by oxygen only by light irradiation with low energy consumption, so that high pressure-sensitive adhesive products such as pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets can be produced. Suitable for sex.

Further, by preparing only a few kinds of oligomers, the performance of the pressure-sensitive adhesive composition can be easily designed, so that a high-performance pressure-sensitive adhesive composition and a pressure-sensitive adhesive product suitable for various uses can be freely prepared. Suitable to get.

Further, according to the manufacturing method of the third invention,
Since the acrylic pressure-sensitive adhesive composition according to the first or second invention is used, a high-performance pressure-sensitive adhesive tape suitably used for various applications can be obtained with high productivity without adversely affecting the environment.

Claims (3)

[Claims] 1. Component (a) 60 to 100% by weight, component (b) 0.1 to 40% by weight, component (c1) 0.1 to 10% by weight, component (d) 0.1 10 to 10% by weight and 100 parts by weight of an acrylic oligomer having a weight average molecular weight in terms of polystyrene of 3000 to 100000 obtained by polymerizing a monomer component containing 0.001 to 2% by weight of the following component (e): Catalyst 0.05
An acrylic pressure-sensitive adhesive composition characterized by containing at most 5 parts by weight. Component (a): Non-3 having an alkyl group having 2 to 18 carbon atoms
(Meth) acrylic acid ester of a secondary alcohol (b) Component: having an unsaturated double bond copolymerizable with the above-mentioned component (a) in one molecule, and having a photocationically polymerizable functional group and a hydroxyl group. (C1) Component: a vinyl compound having a photocationically polymerizable functional group and an unsaturated double bond copolymerizable with the component (a) in one molecule. (D) Component: a hydroxyl group in one molecule. And a vinyl compound having an unsaturated double bond copolymerizable with the above component (a). Component (e): a radical chain transfer agent 2. The following component (a): 60 to 100% by weight, the following component (b): 0.1 to 40% by weight, the following component (c2): 0.1 to 10% by weight, and the following component (d): 0.1 To 10% by weight and 100 parts by weight of an acrylic oligomer (A) having a weight average molecular weight in terms of polystyrene of 3000 to 100000 obtained by polymerizing a monomer component containing 0.001 to 2% by weight of the following component (e). And the following component (a) 6
0 to 100% by weight, component (b) 0.1 to 40% by weight, component (d) 0.1 to 10% by weight and component (e)
Having a weight average molecular weight in terms of polystyrene of 3 obtained by polymerizing a monomer component containing 0.001 to 2% by weight of the component.
Acrylic oligomer (B) 1 of 000 to 100,000
An acrylic pressure-sensitive adhesive composition comprising from 200 to 200 parts by weight and from 0.05 to 5 parts by weight of a photocationic catalyst. Component (a): Non-3 having an alkyl group having 2 to 18 carbon atoms
(Meth) acrylic acid ester of a secondary alcohol (b) Component: having an unsaturated double bond copolymerizable with the above-mentioned component (a) in one molecule, and having a photocationically polymerizable functional group and a hydroxyl group. (C2) component: a vinyl compound having a photocationically polymerizable functional group and an unsaturated double bond copolymerizable with component (a) in one molecule, or photocationic polymerization in one molecule A vinyl compound having an acidic functional group, a hydroxyl group and an unsaturated double bond copolymerizable with the above component (a) (d) component: a hydroxyl group and an unsaturated dihydric copolymerizable with the above component (a) in one molecule. Vinyl compound having heavy bond (e) component: radical chain transfer agent 3. A method of applying the acrylic pressure-sensitive adhesive composition according to claim 1 or 2 to at least one surface of a substrate, and irradiating light to photo-cationically polymerize the pressure-sensitive adhesive composition. Method for producing an adhesive tape.