JPH07316508A - Acrylic tacky tape and its production - Google Patents

Abstract

PURPOSE:To obtain an acrylic tacky tape, capable of manifesting strong resistance to a load or an external force in the peeling direction thereof even in use thereof under relatively high temperature conditions and excellent in productivity and quality by laminating a primer layer and a tacky agent layer onto a tape substrate containing a granular filler and thermally aging the resultant laminate. CONSTITUTION:This acrylic tacky tape is obtained by forming a primer layer comprising a compound having methoxymethyl or methylol group on one surface of an acrylic copolymer sheet prepared by photopolymerizing a photopolymerizable composition comprising an alkyl (meth)acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator and a granular filter, laminating an acrylic tacky agent layer onto the primer layer and then thermally aging the resultant laminate at 40-150 deg.C temperature. Furthermore, the primer layer preferably comprises a reactional product of an acrylic copolymer containing amino group with an epoxy resin or any one of a polyamine compound and a polyfunctional oxazoline compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic pressure-sensitive adhesive tape which exhibits a strong resistance to a load in the peeling direction and an external force when the pressure-sensitive adhesive tape is used under a relatively high temperature condition, and a method for producing the same. Regarding

[0002]

2. Description of the Related Art Conventionally, an adhesive tape having an acrylic polymer sheet as a base material has a higher adhesive strength and weather resistance than other tape base materials, for example, those having a polyolefin or polyurethane polymer sheet as a base material. Since it has excellent properties, for example,
It is mainly used for outdoor use such as attaching parts to automobiles or building materials for building frames.

However, since the adhesive strength is high, a concentrated stress is likely to be exerted on the interface between the pressure-sensitive adhesive layer and the base material layer, so that 150 to 2
When it was used under a high temperature condition of 00 ° C., there was a problem that the adhesive strength at the interface between the pressure-sensitive adhesive layer and the base material layer was reduced, and interfacial peeling occurred. Therefore, one improved technique for solving this problem has been proposed. That is, Japanese Patent Publication No. 2-6
Japanese Patent No. 790 describes a pressure-sensitive adhesive tape composed of a plurality of acrylic compositions.

This improved technique uses a photopolymerizable monomer in an acrylic composition constituting each layer (including a tape base material) in the production of an adhesive tape, before polymerizing these laminated composition layers. In order to prevent interfacial peeling, a monomer chain is made to migrate to the interface of each layer and a polymer chain is formed at the interface between adjacent layers by the subsequent polymerization.

[0005]

However, in the case of the above-mentioned prior art, it is necessary to coat the release sheet with the composition for forming the base layer and the composition for forming the pressure-sensitive adhesive layer at the same time for photopolymerization. . Therefore, it is necessary to equip a coating machine having a plurality of coating heads, and when the thickness of any layer is intended to be changed, for example, when a roll coater is used as the coating machine, a coater is used. There is a problem in that it is necessary to change the positions of the head and rolls or to replace part of the equipment, which necessitates inefficient production.

If the production speed is not kept constant at all times,
When the diffusion rate and the amount of diffusion of the monomers of each coated layer are changed, the performance of the base material layer and the pressure-sensitive adhesive layer becomes uneven, and it is difficult to stabilize the quality. Furthermore, when the polymerization rate of each layer is different In addition to the difference in the polymerization conversion rate between the layers, it is necessary to prevent the odor of the residual layer monomer, so the production rate is regulated by the layer with the slowest polymerization rate. There was also the problem of being forced to speed.

It is an object of the present invention to solve the above-mentioned conventional problems and provide an acrylic pressure-sensitive adhesive tape excellent in productivity and quality stability, and a method for producing the same.

[0008]

The acrylic pressure-sensitive adhesive tape of the present invention according to claim 1 is a photopolymerization comprising an alkyl (meth) acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator, and a granular filler. On at least one surface of an acrylic copolymer sheet obtained by photopolymerizing a polymerizable composition, a primer layer made of a compound having a methoxymethyl group or a methylol group is formed, and an acrylic pressure-sensitive adhesive layer is formed on the primer layer. It is characterized by being.

The acrylic adhesive tape according to claim 2 is
At least one surface of an acrylic copolymer sheet obtained by photopolymerizing a photopolymerizable composition consisting of an alkyl (meth) acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator, and a granular filler is coated with amino. A reaction product of a group-containing acrylic copolymer and an epoxy resin,
A primer layer having an epoxy resin content of 20% by weight or more in the reaction product is formed, and an acrylic pressure-sensitive adhesive layer is formed on the primer layer.

The method for producing an acrylic pressure-sensitive adhesive tape according to claim 3 is a photopolymerizable composition comprising an alkyl (meth) acrylate monomer, a polar group-containing vinyl monomer, a photopolymerization initiator, and a granular filler. On one surface of the acrylic copolymer sheet obtained by photopolymerizing the above, a primer layer comprising at least one compound selected from the group of polyamine compounds and polyfunctional oxazoline compounds is formed, and the acrylic layer is formed on the primer layer. After the pressure-sensitive adhesive layer is laminated, it is heat-cured at a temperature of 40 to 150 ° C.

The tape substrate in the present invention is an acrylic resin obtained by photopolymerizing a photopolymerizable composition comprising an alkyl (meth) acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator, and a granular filler. The acrylic adhesive tape of the present invention, which is a type copolymer sheet, is usually a single-sided adhesive tape or a double-sided adhesive tape that is commercialized as a roll, as well as a label, a patch, etc. Alternatively, a so-called adhesive sheet that is manufactured as a product in which a plurality of sheets are vertically stacked is also included.

Examples of the alkyl (meth) acrylate monomer include alkyl (meth) acrylic acid esters having 1 to 12 carbon atoms. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-
Examples thereof include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate. These can be used alone or in combination of two or more. From the viewpoint of the balance between adhesiveness and cohesiveness, the homopolymer usually has a (meth) acrylic acid ester having a glass transition temperature of −50 ° C. or less as a main component, and methyl (meth) acrylate and ethyl (meth) acrylate are added thereto. It is preferable to use a (meth) acrylic acid ester of a lower alcohol such as

The content of the above-mentioned alkyl (meth) acrylate monomer is 50 to 95% by weight, preferably 70 to 93% by weight, based on all the constituent monomers. When the content of the alkyl (meth) acrylate monomer is less than 50% by weight, when the polymer is used, the cohesive force is too strong and the adhesiveness at the interface with the primer layer described later is poor, and when it exceeds 98% by weight. On the contrary, the cohesive force is reduced and a high shearing force cannot be obtained at the interface.

As the vinyl monomer having a polar group,
Examples thereof include a carboxyl group-containing vinyl monomer or an anhydride thereof, a nitrogen-containing monomer, and a hydroxyl group-containing monomer. Specific examples of the monomer having a polar group include (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid as vinyl monomers having a carboxyl group.

As the nitrogen-containing vinyl monomer,
(Meth) acrylonitrile, N-vinylpyrrolidone, N
-Vinyl caprolactam, acryloyl formolin,
There are (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropylacrylamide and the like, and these can be appropriately selected and used.

As the vinyl monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-
Examples thereof include hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, caprolactane-modified (meth) acrylate, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, and caprolactone-modified (meth) acrylate.

The content of the above vinyl monomer having a polar group is preferably 2 to 20% by weight based on all the constituent monomers. If it is less than 2% by weight, the cohesive force is too low to obtain high shear strength. On the other hand, if it exceeds 20% by weight, the cohesive force is too high and the adhesiveness to the primer layer deteriorates.

Further, in addition to the above-mentioned alkyl (meth) acrylate monomer and vinyl monomer having a polar group, a vinyl monomer having a homopolymer copolymerizable with them having a Tg of 0 ° C. or higher can be appropriately used. As such a monomer, for example, vinyl acetate, vinyl propionate, styrene, isobornyl (meth) acrylate and the like can be preferably used. If the content of this monomer exceeds 30% by weight in all the constituent monomers, the cohesive force becomes too high and the adhesion with the primer layer deteriorates.
The following is preferable. Further, a polyfunctional acrylate can be used in combination for the purpose of crosslinking the acrylic copolymer.

The content of the polyfunctional acrylate is preferably 0.01 to 1 part by weight in all the constituent monomers,
It is more preferably 0.02 to 0.8 parts by weight. 0.0
If it is less than 1 part by weight, the crosslinking will be insufficient to obtain the necessary cohesive force, and if it exceeds 1 part by weight, the crosslinking density will be high and the adhesion to the primer layer will be lowered.

As the photopolymerization initiator, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone (manufactured by Merck & Co., trade name; Darocur 295
9,], α-hydroxy-α, α′-dimethyl-acetophenone (manufactured by Merck, trade name; Darocur 117
3,), methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone (manufactured by Ciba-Geigy, trade name: Irgacure 651), 2-hydroxy-2-cyclohexylacetophenone (manufactured by Ciba-Geigy, trade name: Irgacure 184) and the like. In addition to acetophenone type and ketal type such as benzyl dimethyl ketal, halogenated ketone, acyl phosphinoxide, acyl phosphonate and the like can be mentioned.

The amount of these photopolymerization initiators added is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, based on 100 parts by weight of all the constituent monomers. If the content of the photopolymerization initiator is less than 0.01 part by weight, the polymerization conversion rate may be lowered and only a sheet having a strong monomer odor may be obtained. In some cases, the molecular weight decreases, and as a result, the required cohesive force may not be obtained.

As the granular filler, inorganic hollow fine particles such as glass balloons, shirasu balloons and fly ash balloons, polymethylmethacrylate, acrylonitrile-
Vinylidene chloride copolymer, polystyrene, organic hollow particles made of phenolic resin, glass beads, silica beads, inorganic fine particles such as synthetic mica, organic fine particles such as polyethyl acrylate, polyurethane, polyethylene and polypropylene. To be

The particle size of these granular fillers is such that the average particle size is in the range of 1 to 150 μm. If it is less than 1 μm, high peel strength cannot be obtained,
If it exceeds m, high shear strength cannot be obtained. The amount of the filler added is 0.5 to 1 with respect to 100 parts by weight of all the constituent monomers.
It is preferably 75 parts by weight, preferably 0.7 to 10 parts by weight in the case of hollow fine particles having a relatively small specific gravity, and 10 to 60 parts by weight in the case of hollow particles or organic particles having a specific gravity of about 1. In the case of relatively large particles having a specific gravity of 2 or more, the amount is preferably 70 to 150 parts by weight. It is preferable to mix it in such a manner that the volume fraction thereof falls within the range of 10 to 50% by volume, and if it is less than 10% by volume, high adhesive strength cannot be obtained, and if it exceeds 50% by volume, high shear strength cannot be obtained.

A tackifying resin may be added to the photopolymerizable composition, if necessary. Specifically, a rosin resin, a modified rosin resin, a terpene resin, a terpene phenol resin, a C5-C9 petroleum resin, a chroman resin, or a hydrogenated product thereof is used alone or in combination. can do. However, during the polymerization reaction described below, the polymerization rate may decrease or the molecular weight may decrease, so at this time, a chain transfer agent such as dodecanethiol is added, or the vinyl monomer having the polar group described above. It is necessary to properly adjust the amount of the used.

When an acrylic copolymer sheet is formed using these photopolymerizable compositions, the thickness thereof is 50 μm to
It is good to set it to 5 mm. However, in order to prevent the smoothness of the sheet surface from being hindered by the granular filler, it is necessary to increase the viscosity so that the granular filler is well dispersed and impart thixotropy. When the thickness is 100 μm or less, the viscosity is 1
The coating can be performed even at a 000 cps and a TI value (thixotropy index) of about 1.5, but when a sheet having a thickness larger than that is produced, it is preferable to make the viscosity higher. As a means thereof, an acrylic rubber, a nitrile rubber, an elastomer such as styrene-isoprene-styrene (SIS), a thermoplastic synthetic resin such as polymethylmethacrylate, or polystyrene may be dissolved, or silica having an average particle diameter of 5 μm or less. Inorganic particles of alumina or the like may be mixed.

When the above-mentioned inorganic particles are added, the particles that have been hydrophobized can disperse even the primary particles faster. In addition, the solution viscosity can be increased by preliminarily partially polymerizing a part of the composition without using the above additives. In this case, if a monomer having an unsaturated double bond is used, it should be partially polymerized before adding the monomer to prevent microgel formation. If a gel is partially formed, it may cause defects such as streaks during coating. Further, the monomer to be partially polymerized should be suppressed within the range of 1.5 to 60% by weight based on all the constituent monomers. If it is less than 1.5% by weight, the required viscosity cannot be obtained, and if it exceeds 60% by weight, the coatability becomes poor.

Next, the step of molding a tape base material using the above-mentioned photopolymerizable composition will be described. As a basic process, the composition as described above is applied onto a peelable sheet by using a coating machine such as a roll coater, and thereafter, light is irradiated to polymerize on the peelable sheet.
As the lamps used for light irradiation at this time, those having an emission distribution at a light wavelength of 400 μm or less are used. Specific examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps. Among them, the chemical lamp efficiently emits light in the active wavelength region of the photopolymerization initiator, and since light absorption by the composition other than the photopolymerization initiator is small, light penetrates to the inside to manufacture thick products. It is preferable when

The light irradiation intensity of the photopolymerizable composition 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 intended product. Ordinary acetophenone When a cleavage type photopolymerization initiator having a group is blended, the light irradiation intensity in the wavelength region (usually 365 to 420 nm) effective for photodecomposition of the photopolymerization initiator is 0.1 to 100 mW / cm ² . Is preferred.

The reaction of this photopolymerization is easily inhibited by oxygen in the air and oxygen dissolved in the photopolymerizable composition. For this reason, light irradiation must be carried out using a process technique that can eliminate the inhibition of oxygen. As a method therefor, there is a method in which the coated photopolymerizable composition is covered with a sheet such as PET (polyethylene terephthalate) or Teflon whose surface is peeled off, and the composition is irradiated with light through the sheet. . Further, the reaction may be carried out in an inert zone having a light-transmissive window in which oxygen is replaced by an inert gas such as nitrogen gas or carbon dioxide gas. In the latter method, the oxygen concentration in the irradiation atmosphere must be 5000 ppm or less in order to sufficiently complete the polymerization conversion rate of the composition to 99.7% or more. A suitable oxygen concentration is 300 ppm or less.

When the photopolymerizable composition coated on the peelable sheet reacts rapidly, the peelable sheet and the cover peeling sheet are heated and expanded by the heat of polymerization, and the resulting tape substrate has defects such as vertical stripes. May occur. In this case, it is possible to prevent the occurrence of defects by suppressing the radiant heat from the lamp with the light cut filter, or by rubbing the back surface of the sheet opposite to the irradiation surface with the cooling plate to allow it to pass.

The acrylic copolymer sheet obtained as described above is superior in heat resistance and strength to the conventional tape substrate, and also superior in adhesiveness to the primer layer.

Before forming the pressure-sensitive adhesive layer on the acrylic copolymer sheet formed as described above, a primer layer is formed. The primer layer used in the acrylic pressure-sensitive adhesive tape of claim 1, wherein a compound having a methoxymethyl group (-CH ₂ OCH ₃₎ or methylol group. The compound having a methoxymethyl group is, for example, N-methylol (meth) acrylamide or a polymer thereof, N-methoxymethylated nylon, and the compound having a methylol group is xylene resin, urea resin, ketone resin, alkylphenol. Examples thereof include resins and methylolated melamine resins. These compounds may be used in an organic solvent solution type, an aqueous solution type, or a water dispersion type, if necessary.

Both the compound having a methoxymethyl group and a methylol group are alkyl (meth) which is a tape base component.
Since it has good adhesiveness to acrylates and vinyl monomers having a polar group, when it is used as a primer, interfacial peeling between the tape base material and the tape base material does not occur.

The primer layer used in the acrylic pressure-sensitive adhesive tape according to claim 2 comprises a cured product of an amino group-containing acrylic copolymer and an epoxy resin. As the amino group-containing acrylic copolymer, a product obtained by grafting ethyleneimine by aminoethylation reaction to a copolymer containing polymethyl (meth) acrylic acid ester as a main component is commercially available (for example, Nippon Shokubai). (Product name: Polyment NK # 300 series). A copolymer of amino group-containing monomers such as acrylamide can also be used.

As the above-mentioned epoxy resin, bisphenol A type diglycidyl ether (made by Yuka Shell, trade name:
Epicoat 828), polyethylene glycol diglycidyl ether (Nagase & Co., Denacol 832),
Urethane-modified epoxy, dimer acid-modified epoxy resin and the like are preferably used.

A cured product can be obtained by reacting the acrylic copolymer with an epoxy resin. The content of these epoxy resins is 20 to 100 parts by weight, preferably 30 to 70 parts by weight, based on 100 parts by weight of the amino group-containing acrylic copolymer. When it is 20 parts by weight or less, the heat resistance of the layer is lowered, and as a result, the heat resistance of the adhesive tape itself cannot be obtained. If it exceeds 10 parts by weight, the adhesive strength will decrease.

The thickness of the primer layer is 0.1 to 10 μm.
m is preferable, and more preferably 0.5 to 5 μm.
When it is thinner than 0.1 μm, the heat resistance is lowered, and when it exceeds 10 μm, the adhesive strength is lowered.

The above composition is a solvent type, an emulsion type,
It can be used in a water-soluble form and can be applied to a tape base material by a conventional means such as a gravure coater or a bar coater to form a primer layer.

In the case of the acrylic pressure-sensitive adhesive tapes of claims 1 and 2, the coating amount of the primer is 0.1 after drying.
Is preferably to 10 g / m ^2, more preferably from 0.5 to 5 g / m ^2. When the coating amount is less than 0.5 g / m ² , it is difficult to apply the coating with high thickness accuracy, and it is also difficult to exert a sufficient function as a primer layer. A coating amount of more than 10 g / m ² is unnecessary.

Since the pressure-sensitive adhesive tape according to the second aspect uses such a primer layer, the pressure-sensitive adhesive tape is excellent in adhesiveness to the tape base material made of the acrylic polymer monomer or the like and can be improved in heat resistance.

The primer layer used in the method for producing an acrylic pressure-sensitive adhesive tape according to claim 3 has an amino group (-N
H ₂ ) -containing polyamine compounds and polyfunctional oxazoline compounds. The above compounds are used as an organic solvent type solution type, an aqueous solution type, and a water dispersion type, and may be used in a state of 100% of active ingredient.

The polyamine compound is a copolymer containing methyl methacrylate as a main component, an acrylic polymer having an ethyleneimine chain in its side chain (for example, Nippon Shokubai Co., Ltd., trade name: polyment), and metaxylenediamine. Examples thereof include polyamines (for example, manufactured by Mitsubishi Gas Chemical Co., Inc., trade name: Gascamine), which is a reaction product of epichlorohydrin.

As the polyfunctional oxazoline compound, 2,
2 '-(1,3-phenylene) -bis (2-oxazoline), polystyrene copolymer having an oxazoline ring in the side chain, polystyrene-acrylonitrile copolymer (for example, Nippon Shokubai Co., Ltd., trade name: Epocros) Etc.

As the primer layer, the polyamine compound and the polyfunctional oxazoline compound may be used alone or in combination. The coating amount of the primer is preferably 0.1 to 30 g / m ² after drying,
It is more preferably 0.5 to 1 g / m ² .

In the present invention of claims 1 to 3, an acrylic pressure-sensitive adhesive layer is formed on each primer layer formed as described above. The monomer and the polymerization method for obtaining the acrylic pressure-sensitive adhesive are not particularly limited, but when the monomer forming the acrylic copolymer sheet used for the tape base material is used, the adhesive property with the primer layer is excellent. Therefore, it is preferable. The pressure-sensitive adhesive layer composition is usually compounded with an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent or the like for crosslinking. If it is not crosslinked, the heat resistance and the creep property will decrease. The degree of this crosslinking can be easily determined by immersing in a good solvent such as ethyl acetate, toluene, tetrahydrofuran, etc., filtering the insoluble matter (gel), and measuring the weight fraction thereof. The preferred gel fraction is 50 to 90% by weight.

This acrylic pressure-sensitive adhesive may be a solvent-type pressure-sensitive adhesive polymerized in a solvent, or an emulsion-type pressure-sensitive adhesive polymerized in water, and as in the case of the above-mentioned base material layer. It may be a compound obtained by subjecting a mixture of monomers to bulk polymerization by irradiating light such as ultraviolet rays. In this case, in order to crosslink, the above-mentioned crosslinking agent may be replaced by the above-exemplified monomer having two or more copolymerizable unsaturated double bonds in the molecule as a base layer forming monomer.

The means for laminating the pressure-sensitive adhesive obtained as described above on the tape substrate on which the primer layer is formed is not particularly limited, and it is directly coated on the primer layer by using an ordinary roll coater. Alternatively, a transfer method is used in which a three-layer structure of tape base material layer / primer layer / adhesive layer is formed by overlaying an adhesive layer formed by applying and drying an adhesive on a release paper separately. May be.

In the method for producing an acrylic pressure-sensitive adhesive tape according to claim 3, after the pressure-sensitive adhesive layer is formed on the primer layer,
This is heated to a temperature of 40 to 150 ° C. and cured. The curing period is preferably about 30 minutes or more. 40 ° C
If it is lower than this, a high degree of adhesion effect of the primer layer cannot be obtained, and if it exceeds 150 ° C, the adhesive strength is lowered. By heating and curing the primer layer, the bond of the primer layer to the tape base material and the pressure-sensitive adhesive layer becomes strong, and the resistance to the peeling force at room temperature and high temperature becomes very strong.

[0049]

In the acrylic pressure-sensitive adhesive tapes according to claims 1 and 2, since the acrylic copolymer sheet contains the granular filler, the anchoring effect is obtained at the interface with the primer layer and the adhesiveness is improved. And the mechanical strength of the tape base material itself is improved.

The acrylic copolymer sheet which is the tape substrate is composed of a polymer of an alkyl (meth) acrylate monomer and a monomer having any polar group of carboxyl group, hydroxyl group and carbonyl group. On the other hand, since a primer layer made of a component highly reactive to these polar groups is provided and an acrylic adhesive layer is provided on this primer layer, this adhesive tape is a tape substrate / primer layer / adhesive layer. Each layer of is firmly bonded,
It does not easily peel off at each interface.

In the method for producing an acrylic pressure-sensitive adhesive tape according to claim 3, a tape layer is formed by forming a primer layer composed of one or two compounds of a polyamine compound and a polyfunctional oxazoline compound, and curing the primer layer by heating. The bond of the primer layer to the material and adhesive layer becomes strong, and the resistance to peeling force at room temperature and high temperature is very strong,
The quality of the obtained adhesive tape is stable.

[0052]

[Molding of acrylic copolymer sheet]

(Sheet 1) 850 parts by weight of 2-ethylhexyl acrylate (hereinafter simply referred to as "part"), 50 parts of acrylic acid, 100 parts of N-vinylpyrrolidone, 0.2 part of n-dodecanethiol
Part, 2,2-dimethyl-2-phenylacetophenone (manufactured by Ciba Geigy, trade name: Irgacure) 3.0
Parts, high-density polyethylene fine particles having an average particle diameter of 20 μm (Mitsui Petrochemical Co., Ltd., trade name: Miperon XM-220,
After stirring and mixing 420 parts of a specific gravity of 0.95) in a separable flask until uniformly dispersed, nitrogen gas was purged to remove dissolved oxygen. When the composition was irradiated with ultraviolet rays using a black light lamp, the temperature of the composition rose and the viscosity increased at the same time. The viscosity of the composition increased as the temperature of the composition increased. When the temperature of the composition further increased by 5 ° C, the light irradiation was stopped.

The resulting partially photopolymerized thickened composition had a polymerization conversion of 3.7% and a viscosity of 2200 cps. Further, 0.2 part of hexanediol diacrylate was added, and then coated on a PET film having a thickness of 38 μm, which had been subjected to a peeling treatment, so that the thickness at the end of the polymerization would be 1.0 ± 0.1 mm. The coated surface was coated with the same PET film such that its release treated surface was in contact with the coated surface. Next, PE covered with a chemical lamp
The lamp height was adjusted so that the irradiation intensity on the T film was ² mw / cm ^2, and irradiation was carried out for 8 minutes. The residual monomer of the obtained acrylic polymer sheet was less than 0.1%, and the gel fraction was 95%.

(Sheet 2) isononyl acrylate 95
0 part, N-vinylcaprolactam 50 parts, hydrophilic silica (manufactured by Nippon Aerosil Co., Ltd., trade name; Aerosil 200) 3
0 parts with dissolver kakuhan machine for 4 hours 1000
The mixture was stirred and mixed at a speed of rpm to obtain a viscous liquid. 50 parts of a glass balloon having an average particle diameter of 45 μm (manufactured by Asahi Glass Co., Ltd., trade name, CEL-STARZ-27,
Specific gravity = 0.27), photoinitiator (manufactured by Ciba Geigy,
Trade name: Irgacure 651) 3.0 parts and hexanediol diacrylate 0.3 parts were stirred and mixed until uniform, and then nitrogen gas was purged to remove dissolved oxygen. Then, an acrylic polymer sheet having a thickness of 1.5 mm was obtained in the same manner as the sheet 1.

(Sheet 3) 700 parts of 2-ethylhexyl acrylate, 250 parts of isooctyl acrylate, 50 parts of acrylic acid, hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd.,
70 parts of trade name; Aerosil R976) was stirred and mixed with a dissolver type stirrer for 30 minutes at a speed of 1000 rpm to obtain a viscous liquid. Average particle size = 70 μm
0.82 parts of hollow fine particles (made by Matsumoto Yushi-Seiyaku Co., Ltd., trade name: Matsumoto Microsphere F80ED, specific gravity 0.02) consisting of vinylidene chloride-acrylonitrile copolymer of
Hexanediol diacrylate 0.3 parts, photopolymerization initiator (Ciba Geigy, trade name; Irgacure 651)
After 1.0 part was stirred and mixed until uniform, nitrogen gas was purged to remove dissolved oxygen. Then, an acrylic polymer sheet having a thickness of 1.0 mm was obtained in the same manner as the sheet 1.

(Sheet 4) An acrylic polymer sheet having a thickness of 1 mm was obtained in the same manner as in Sheet 2 except that the monomer composition of the photopolymerizable composition was 995 parts of isooctyl acrylate and 5 parts of acrylic acid. It was

(Sheet 5) As a monomer composition of the photopolymerizable composition, 700 parts of 2-ethylhexyl acrylate,
An acrylic polymer sheet having a thickness of 0.8 mm was obtained in the same manner as the sheet 3 except that 300 parts of N-vinylpyrrolidone was used.

[Preparation of Primer and Coating on Substrate] (Primer 1) 5% ethyl acetate solution of N-methylol acrylamide polymer having a weight average molecular weight of 2000 to 3000 obtained by a photopolymerization method at room temperature.

(Primer 2) 2% solution of N-methoxymethylated nylon in methanol (manufactured by Teikoku Kagaku Co., trade name:
Resin M-20).

(Primer 3) A 5% toluene solution of a methylolated melamine resin (Sumikol series, manufactured by Sumitomo Chemical Co., Ltd.).

(Primer 4) A toluene 3% solution of an amino group-containing acrylate polymer (a polymer having methylmethacrylate as a main component and having an ethyleneimine group in its side chain) (NK series manufactured by Nippon Shokubai Chemical Co., Ltd.).

(Primer 5) Acrylic polymer containing amino group (aminoethylated product of polymethylmethacrylate, manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name: NK-380)
2 g of 50% toluene solution of bisphenol A type diglycidyl ether (trade name: Epicoat 828, manufactured by Yuka Shell Co., Ltd.) was mixed with 100 g of a 3% solution of toluene in Example 3 to react.

(Primer 6 (when epoxy resin is insufficient)) Toluene 3 of amino group-containing acrylic polymer (aminoethylated polymethylmethacrylate)
% Solution 100 g, bisphenol A type diglycidyl ether 50% toluene solution 1 g mixed reaction product solution.

(Primer 7 (when no epoxy resin is used)) Amino group-containing acrylic polymer (aminoethylated polymethylmethacrylate ester, manufactured by Nippon Shokubai Kagaku Co., trade name: NK-380) in toluene 3% .

[Adhesive Preparation] (Adhesive 1) A 2-ethylhexyl acrylate 700 was placed in a separable flask equipped with a cooling tube, a thermometer, and a stirrer.
Parts, n-butyl acrylate 250 parts, acrylic acid 50
Parts, 0.2 parts of n-dodecanethiol and 90 parts of ethyl acetate
It was charged together with 0 part, heated to reflux under a nitrogen gas atmosphere, held for 20 minutes, and then charged with benzyl peroxide 1.0.
A solution prepared by dissolving 50 parts of ethyl acetate in 50 parts of ethyl acetate was added dropwise and reacted for 4 hours. After that, a solution of 1.0 part of benzyl peroxide in 50 parts of ethyl acetate was further added dropwise, and the reaction was further continued for 3 hours. Then, 500 parts of toluene was added and mixed with stirring to obtain a solvent-type pressure-sensitive adhesive having a viscosity of 12000 cps. The solid content was 39.5%.

(Adhesive 2) Monomer composition of 898 parts of 2-ethylhexyl acrylate and 1 of N-vinylpyrrolidone
Polymerization and dilution were carried out in the same manner as the pressure-sensitive adhesive 1 except that the amount was changed to 00 parts and 2 parts of 2-hydroxyethyl methacrylate. The solid content was 39.8% and the viscosity was 14200 cps.

(Adhesive 3) Adhesive solution 100 of adhesive 1
6 parts of a disproportionated rosin ester (manufactured by Arakawa Chemical Co., Ltd., trade name: Super Ester A-115) having a softening point of 115 ° C.,
Polymerized rosin ester with a softening point of 135 ° C (Arakawa Chemical Co., Ltd.,
Trade name: Pencel D135) 4 parts and toluene 5 parts were mixed.

(Adhesive 4) Monomer composition of 970 parts of 2-ethylhexyl acrylate, 30 parts of acrylic acid, n-
Polymerization and dilution were carried out in the same manner as PSA 1 except that 0.1 part of dodecanethiol was used. The solid content is 40.0%,
The viscosity is 12000 cps. This adhesive 4 can be used as a soft adhesive for temporary fixing.

(Examples 1 to 5) According to the combinations shown in Table 1, 1 g of a primer was applied to both sides of the sheet with a bar coater.
/ M ^{2 and} was dried at 90 ° C for 5 minutes to form a primer layer. A pressure-sensitive adhesive layer having a thickness of 30 μm was formed on the primer layers on both sides by a transfer method using a laminating machine to obtain a pressure-sensitive adhesive tape.

Comparative Example 1 Example 1 except that the sheet, primer and pressure-sensitive adhesive layer were used according to the combinations shown in Table 1.
Adhesive tapes were obtained in the same manner as described above.

Comparative Example 2 An adhesive tape was obtained in the same manner as in Comparative Example 1 except that the primer was not used.

Performance Evaluation Each pressure-sensitive adhesive tape of Examples 1-5 and Comparative Examples 1-2 was 20 m long.
Cut into a size of mx 20 mm, stick to one side of SUS304 as an adherend, stick a 100 μm thick aluminum foil as a backing to the other side, and press the aluminum plate foil surface back and forth with a 2 kg roller for 2 cycles. did. After this was left at 23 ° C. for 3 days, a load of 1 kg was applied to the surface of the aluminum foil in the shearing direction of the adhesive tape, and the dropping temperature was measured when the temperature was raised at a rate of 3 ° C./5 minutes. The results are shown in Table 1.

[0073]

[Table 1]

As is clear from Table 1, all of Examples 1 to 5 were held up to 200 ° C. and showed excellent heat resistance, while Comparative Examples 1 to 2 had 100 to 14
It dropped at 0 ° C and had poor heat resistance.

(Examples 6 to 10) According to the combinations shown in Table 2, both sides of the sheet were coated with a primer using a bar coater at 1 g / m ² and dried at 110 ° C. for 5 minutes to form a primer layer. . A pressure sensitive adhesive layer having a thickness of 30 μm was formed by a transfer method using the primer layer laminating machine on both sides to obtain a pressure sensitive adhesive tape.

(Comparative Examples 3 to 4) Adhesive tapes were obtained in the same manner as in Examples 6 to 10 except that the sheet, the primer and the adhesive layer were used according to the combinations shown in Table 2.

Performance Evaluation Each of the pressure-sensitive adhesive tapes of Examples 6 to 10 and Comparative Examples 3 to 4 was used.
Cut into a size of 20 mm x 20 mm, and stick it on one side to SUS304 that has been polished with sandpaper (# 280) as an adherend, and on the other side stick a 100 μm thick aluminum foil as a backing to the aluminum plate foil surface of 2 kg.
It was crimped back and forth twice with the roller. This is 23 ℃, 55
After being left under% RH for 3 days and then left in an oven set to 200 ° C. for 20 minutes, a load of 1 kg was applied to the aluminum foil surface in the shearing direction of the adhesive tape, and the time until the weight dropped was measured. The results are shown in Table 1.

[0078]

[Table 2]

As is clear from Table 2, Examples 6 to 10
Since the primer layers were properly cured with an epoxy resin, all of them showed excellent heat resistance at 200 ° C., but Comparative Examples 3 to 4 had no heat resistance at all.

(Examples 11 to 15) According to the combinations shown in Table 3, a primer was applied on both sides of the sheet using a bar coater at 1 g / m ² and dried at 90 ° C. for 5 minutes to form a primer layer. did. A pressure-sensitive adhesive layer having a thickness of 30 μm was formed on the primer layers on both sides by a transfer method, and heat-cured at 50 ° C. for 1 hour.

(Example 16) An adhesive tape was obtained in the same manner as in Example 11 except that the curing temperature was 90 ° C.

(Comparative Examples 5 and 6) Adhesive tapes were obtained in the same manner as in Example 11 except that the sheet, the primer and the pressure-sensitive adhesive layer were used in the combinations shown in Table 3 except that they were not heat-cured.

Performance Evaluation Two adhesive tapes of Examples 11 to 16 and Comparative Examples 5 and 6 were used.
Cut into 0 mm x 100 mm, and use this for JIS H400
Aluminum alloy 1100P (25 mm x
100mm) on both sides and 2kg roller 2
After back-and-forth crimping and leaving at 23 ° C for 72 hours,
Separate test pieces left for 1 hour at 100 ° C. and 100 ° C. were subjected to a T-peel test at a tensile speed of 200 mm / min at each temperature to examine the fracture strength and fracture morphology. The results are shown in Table 3.

[0084]

[Table 3] [Note] Evaluation of fracture mode ○: Cohesive failure of base material layer ×: Failure of primer layer between base material layer and adhesive layer

As is clear from Table 3, Examples 11 to 1
Since No. 6 was heat-cured by using the primer layer according to claim 3, the anchoring property of the primer layer with the base material layer and the pressure-sensitive adhesive layer was excellent under both conditions of normal temperature and high temperature, and high adhesive strength was obtained. Have. However, it can be seen that the comparative example did not cure by heating, and thus the anchoring property was weak and the adhesive force was weak.

[0086]

The acrylic pressure-sensitive adhesive tapes according to the first and second aspects of the present invention include granular fillers in the tape base material, and therefore are anchored at the interface between the primer layer and the pressure-sensitive adhesive layer and the base material layer. Since the effect is great, the adhesion between layers is excellent,
Further, the mechanical strength of the tape base material itself is improved, and the productivity and quality are stable.

In the method for producing an acrylic pressure-sensitive adhesive tape according to claim 3, a primer layer comprising one or two compounds of a polyamine compound and a polyfunctional oxazoline compound is formed, and the primer layer is cured by heating to form a primer layer. Since the adhesiveness of is improved, the bond of the primer layer to the tape base material and the pressure-sensitive adhesive layer becomes strong, the resistance to the peeling force at room temperature and high temperature is very strong, and the productivity is good,
In addition, an adhesive tape with stable quality can be obtained.

Claims (3)

[Claims] 1. An acrylic copolymer sheet obtained by photopolymerizing a photopolymerizable composition comprising an alkyl (meth) acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator, and a granular filler. An acrylic pressure-sensitive adhesive tape, comprising a primer layer formed of a compound having a methoxymethyl group or a methylol group on at least one surface, and an acrylic pressure-sensitive adhesive layer formed on the primer layer. 2. An acrylic copolymer sheet obtained by photopolymerizing a photopolymerizable composition comprising an alkyl (meth) acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator, and a granular filler. At least one surface is a reaction product of an amino group-containing acrylic copolymer and an epoxy resin, wherein the epoxy resin component in the reaction product is 2
An acrylic pressure-sensitive adhesive tape, comprising a primer layer of 0% by weight or more, and an acrylic pressure-sensitive adhesive layer formed on the primer layer. 3. An acrylic copolymer sheet obtained by photopolymerizing a photopolymerizable composition comprising an alkyl (meth) acrylate monomer, a vinyl monomer having a polar group, a photopolymerization initiator, and a granular filler. On one surface, a primer layer made of at least one compound selected from the group of polyamine compounds and polyfunctional oxazoline compounds is formed, an acrylic pressure-sensitive adhesive layer is laminated on the primer layer, and then a temperature of 40 to 150 ° C. A method for producing an acrylic pressure-sensitive adhesive tape, which comprises heat-curing at.