JP5559952B2 - Active energy ray adhesive strength-reducing adhesive composition and adhesive tape - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive that can be used for surface protection or back surface reinforcement during the manufacture of electronic components and printed circuit boards, particularly flexible printed circuit boards, and can be peeled off without adhesive residue after production, and a pressure-sensitive adhesive tape using the same. .

  In general, a flexible printed circuit board (FPC) is often manufactured by forming a conductive circuit by a subtractive method on a CCL made of a conductive layer such as copper and an insulating layer such as polyimide. By cutting the CCL into single sheets and attaching an adhesive sheet to the insulating layer for reinforcement, and then feeding it into the FPC manufacturing process, yield loss due to bending or wrinkling of the CCL during the manufacturing process is prevented. It is known that it can be done. Before being put into the manufacturing process, re-pasteability is required when the sticking position is wrong in the sticking work to the insulating adhesive sheet. In addition, a plating process may be performed to form a connection terminal with an external circuit in the manufacturing process, and the adhesive layer of the adhesive sheet is also required to have a plating solution resistance. Furthermore, after the FPC is manufactured, the pressure-sensitive adhesive sheet is required to be easily peeled without any adhesive residue.

  On the other hand, Patent Document 1 proposes an electronic member pressure-sensitive adhesive tape that has water resistance for a dicing process and whose adhesive strength is reduced by radiation irradiation. However, the pressure-sensitive adhesive tape uses a hydroxyl group equivalent of 1.0 to 2.0 times the isocyanate group equivalent, so that the hydroxyl group always remains after the pressure-sensitive adhesive layer is crosslinked. However, what is required in the process in which the adhesive tape is used is water resistance excluding releasability and the like, and stricter chemical resistance is not required. When used in the presence of a plating solution or the like, there is a problem that the presence of a hydroxyl group reduces the resistance to the chemical solution and causes problems when the adhesive tape is peeled off.

Moreover, the adhesive tape of patent document 2 is a reinforcing tape at the time of FPC manufacture, and can maintain the adhesive strength even after a high heat and high pressure condition by combining a polymer using a monomer having a specific composition and a polymerization inhibitor, and thereafter In addition, it has been proposed to use a photopolymerizable adhesive composition whose adhesive strength is reduced by ultraviolet irradiation as an adhesive tape. However, the pressure-sensitive adhesive tape has a very high adhesive force before ultraviolet irradiation, and has a problem that it cannot be re-attached.
JP 2004-75940 A Japanese Patent No. 3525938

The present invention is applied to electronic parts, printed circuit boards and the like for surface protection and reinforcement of the back surface, has good re-stickability, has chemical resistance to etching liquid and plating liquid, etc., after the manufacturing process An object of the present invention is to provide an active energy ray-adhesive adhesive composition and an adhesive tape coated with the same, which can be easily peeled off with no adhesive residue when the adhesive energy decreases.

  The present invention comprises a polymer (A) having a hydroxyl group, an active energy ray-curable compound (B), a photopolymerization initiator (C) and an isocyanate-based curing agent (D), and the above (A) to (C). The equivalent ratio of the isocyanate group in (D) with respect to the total of the hydroxyl groups possessed by is greater than 1 and 30 or less.

  In the present invention, the polymer (A) having a hydroxyl group is a polymer (A-1) further having a carboxyl group, the (A-1), the active energy ray-curable compound (B), and the initiation of photopolymerization. The above active energy ray adhesive, wherein the equivalent ratio of isocyanate groups in the isocyanate-based curing agent (D) to the total of hydroxyl groups and carboxyl groups in the agent (C) is 0.05 to 0.35 The present invention relates to a force disappearing pressure-sensitive adhesive composition.

  The present invention is also a pressure-sensitive adhesive tape comprising a base material, a pressure-sensitive adhesive layer (I) formed from the above active energy ray-adhesive pressure-sensitive adhesive composition, and a release sheet, wherein the release sheet is peeled off. It is related with the adhesive tape characterized by arithmetic mean roughness (Ra) of a process surface being 0.10-2 micrometers.

  By using the active energy ray adhesive disappearance type pressure-sensitive adhesive composition of the present invention, good re-sticking property when applied to a printed circuit board or the like for reinforcement, and chemical resistance to an etching solution or a plating solution is provided. In addition, after the production process, it has become possible to provide an adhesive tape that can be easily peeled off without any adhesive residue by irradiation with active energy rays. As a result, it was possible to reduce the loss during the production of the printed circuit board and to improve the yield.

  The preferable aspect in which the active energy ray adhesive strength disappearance type adhesive composition and adhesive tape of this invention are used is demonstrated.

  The active energy ray-adhesive pressure-sensitive adhesive composition of the present invention forms a cross-linked structure by reacting the hydroxyl group in the polymer (A) having a hydroxyl group with the isocyanate curing agent (D) by an operation such as heating. (This process is also called “curing”). Therefore, for example, the active energy ray adhesive strength disappearing pressure-sensitive adhesive composition is coated on a base material, the solvent contained as needed is volatilized by an operation such as heating, and the composition is cross-linked to form a pressure-sensitive adhesive layer. Form (I). Here, the pressure-sensitive adhesive layer (I) refers to a state in which active energy rays are not yet irradiated.

  Next, the pressure-sensitive adhesive sheet can be obtained by bonding the formed pressure-sensitive adhesive layer (I) and the release treatment surface of the release sheet.

  Then, when using an adhesive tape for FPC manufacture, for example, a peeling sheet is peeled and it affixes on the insulating layer side of CCL for reinforcement. CCL is generally used in FPC manufacturing processes that are manufactured by, for example, etching by a subtractive method, and further through processes such as plating, but when performing the above methods, adhesive tapes are manufactured. Since it is exposed to an etching solution or a plating solution during the process, chemical resistance is required. Examples of the chemical used in the etching solution include ferric chloride and cupric chloride. After the etching process, for example, there is an etching resist stripping process using an aqueous caustic soda solution, followed by a neutralizing process using an acidic aqueous solution. Thereafter, a plating process such as electroless or electrolytic tin plating, nickel plating, and gold plating may be performed under acidic or alkaline conditions. After the FPC is manufactured in this way or when the reinforcing adhesive tape is no longer necessary, the adhesive layer (I) of the adhesive sheet is irradiated with active energy rays to further increase the pressure-sensitive adhesive layer (I). Dimensional cross-linking occurs and the adhesive strength decreases or disappears, and the adhesive tape can be peeled without any adhesive residue.

  In the active energy ray-adhesive pressure-sensitive adhesive composition of the present invention, the photopolymerization initiator (C) and the active energy ray-curable compound (B) react by irradiation with active energy rays, and the adhesive layer (I) further By highly three-dimensionally cross-linking, the adhesive strength is reduced or disappears from before irradiation, and it is possible to easily peel from the adherend.

  Generally, a pressure-sensitive adhesive contains a polymer containing a functional group that serves as a cross-linking point with a curing agent and a curing agent. When processed into a pressure-sensitive adhesive tape, the pressure-sensitive adhesive is aggregated in the pressure-sensitive adhesive layer by crosslinking with the curing agent. Force is applied and adhesive strength is developed. The hydroxyl group of the polymer (A) having a hydroxyl group contained in the active energy ray-adhesive adhesive composition of the present invention also serves as a crosslinking point with the isocyanate curing agent (D). The hydroxyl group is derived from a hydroxyl group-containing monomer. The hydroxyl group-containing monomer becomes a polymer by copolymerizing with other copolymerizable monomers. Examples of the polymer that can be used as the active energy ray-adhesive adhesive composition include acrylics, urethanes, and polyesters, but acrylics are preferred because of the balance of adhesive properties and ease of composition change.

  The hydroxyl group-containing monomer is preferably used in an amount of 0.01 to 5 parts by weight, more preferably 0.05 to 2 parts by weight, and 0.05 to 1 part by weight among 100 parts by weight of all monomers to be copolymerized. Further preferred. Since the hydroxyl group becomes a crosslinking point with the isocyanate curing agent (D), if the hydroxyl group-containing monomer is less than 0.01 part by weight, the crosslinking density may be reduced and the cohesive force may be insufficient. And there is a risk that cross-linking will be excessive and tack and adhesive strength will be insufficient. The glass transition temperature of the polymer (A) having a hydroxyl group is preferably −60 to −10 ° C. from the balance of cohesive force and adhesiveness. The weight average molecular weight is preferably 200,000 to 2,000,000, more preferably 400,000 to 1,500,000 from the viewpoints of cohesion and tack. Examples of the copolymerization method for obtaining the polymer (A) having a hydroxyl group include solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, active energy ray irradiation polymerization, and the like. Solution polymerization is preferred. The weight average molecular weight (Mw) is measured using a standard polystyrene calibration curve by gel permeation chromatography.

  Examples of the hydroxyl group-containing monomer used to obtain an acrylic polymer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, -4-hydroxybutyl acrylate, methylol acrylamide, vinyl alcohol, ethylene glycol monomethacrylate, and the like. It is done.

  The other copolymerizable monomer may be any monomer copolymerizable with a hydroxyl group-containing monomer, such as acrylic acid, methacrylic acid, itaconic acid, itaconic anhydride, crotonic acid, maleic acid, maleic anhydride, acrylamide. Glycidyl acrylate, glycidyl methacrylate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, dimethylamino methacrylate, diethylaminomethacrylate, methyl acrylate, methacrylate methyl, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate , Isobutyl methacrylate, isopropyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl Methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate, vinyl acetate, acrylonitrile, styrene, alpha-methyl styrene, and vinyl toluene.

The polymer (A) having a hydroxyl group preferably further has an acryloyl group or a methacryloyl group in the side chain. When an acryloyl group or a methacryloyl group is introduced into the side chain, the three-dimensional crosslinking density after irradiation with active energy rays is further improved, and the adhesiveness disappearance is also improved. As a method for introducing an acryloyl group or a methacryloyl group into a side chain, for example,
(1) A method of adding an isocyanate group of 2-methacryloyloxyethyl isocyanate which is a compound having an isocyanate group and a methacryloyl group in the molecule to the hydroxyl group of the polymer;
(2) Acrylic acid is used as part of the monomer to obtain an acrylic polymer having a carboxyl group in the side chain, and the epoxy group of glycidyl methacrylate which is a compound having an epoxy group and a methacryloyl group in the molecule. A method of adding
Any known method can be used.

  In the present invention, the isocyanate curing agent (D) is used, but when the pressure-sensitive adhesive layer (I) is formed, if there is an unreacted hydroxyl group that has not reacted with the isocyanate curing agent (D), However, the chemical solution is drawn into the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive tape is liable to float and peel off in the FPC manufacturing process, and there is a risk of adhesive residue at the time of peeling.

  The isocyanate curing agent (D) is used in an amount of the isocyanate in (D) with respect to the total of hydroxyl groups in the polymer (A) having a hydroxyl group, the active energy ray-curable compound (B) and the photopolymerization initiator (C). It is important to use the group at a ratio such that the equivalent ratio of the group exceeds 1 and is 30 or less, and it is preferable to use the group at a ratio such that the equivalent ratio is 1.01 to 25.

  As other than the polymer (A) having a hydroxyl group, the active energy ray-curable compound (B), the photopolymerization initiator (C), etc. do not necessarily have to have a hydroxyl group. What is necessary is just to select suitably according to the objective. However, in consideration of chemical resistance, it is preferable not to contain a hydroxyl group other than the polymer (A) having a hydroxyl group. In addition, a very small amount of water is unavoidable in the adhesive. For this reason, the isocyanate curing agent (D) also reacts with water, and a part thereof cannot react with the hydroxyl group of the polymer. Therefore, when the equivalent ratio of the isocyanate group to the hydroxyl group is 1 or less, the hydroxyl group remains and lowers the chemical resistance. If it exceeds 30, there is a risk of adhesive residue at the time of peeling.

As said isocyanate type hardening | curing agent (D), it reacted with diisocyanates, such as tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, those trimethylol propane adduct bodies, and water, for example. Examples include a burette body and a trimer having an isocyanurate ring.
Moreover, it is preferable that the polymer (A) having a hydroxyl group is a polymer (A-1) further having a carboxyl group. When all the hydroxyl groups react with the isocyanate curing agent (D), the adhesive strength of the adhesive layer (I) tends to be insufficient, and the adhesive tape floats from the adherend during the FPC manufacturing process, which may cause peeling. . Therefore, it is preferable to include a carboxyl group to improve the adhesive force and prevent the pressure-sensitive adhesive tape from floating and peeling off during the production process. When the polymer (A) having a hydroxyl group is a polymer (A-1) containing a carboxyl group, the amount of the isocyanate curing agent (D) used is (A-1), an active energy ray-curable compound (B). ) And the photopolymerization initiator (C) should be used at a ratio such that the equivalent ratio of isocyanate groups in the isocyanate-based curing agent (D) to the total of hydroxyl groups and carboxyl groups of the photopolymerization initiator (C) is 0.05 to 0.35. Is preferred. From the above, it is preferable to use more carboxyl groups than the total of hydroxyl groups in order to increase the adhesive strength. Further, the polymer (A) having a hydroxyl group may appropriately contain other functional groups in addition to the carboxyl group.
The isocyanate curing agent (D) also reacts with the carboxyl group, but since the reaction with the hydroxyl group is faster, the carboxyl group often remains unreacted. When a carboxyl group remains in the pressure-sensitive adhesive layer, there is little influence on chemical resistance, but when a hydroxyl group remains, the chemical resistance is greatly reduced with a very small amount remaining.

  The action of the active energy ray-curable compound (B) contained in the active energy ray-adhesive adhesive-type pressure-sensitive adhesive composition is as follows. When the functional compound (B) undergoes a more advanced three-dimensional crosslinking, the adhesive strength of the pressure-sensitive adhesive layer (I) is reduced or eliminated, and can be easily peeled off from the adherend. The active energy ray-curable compound (B) is a compound having a (meth) acryloyl group (referred to as “(meth) acryloyl group” together with “acryloyl group” and “methacryloyl group”) as a functional group. It is preferable to use a polyfunctional monomer having 3 or more acryloyl groups and / or a urethane acrylate oligomer having 6 or more (meth) acryloyl groups. The active energy ray-curable compound (B) is preferably used in an amount of 20 to 300 parts by weight, more preferably 30 to 150 parts by weight, based on 100 parts by weight of the polymer (A) having a hydroxyl group.

  Examples of the polyfunctional monomer having three or more (meth) acryloyl groups used as the active energy ray-curable compound (B) include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, and propoxy. Trimethylolpropane triacrylate, pentaerythritol triacrylate, tetramethylolpropane triacrylate, tetramethylolmethane triacrylate, pentaerythritol tetraacrylate, caprolactone-modified trimethylolpropane triacrylate, ethoxylated isocyanuric acid triacrylate, tri (2-hydroxy Ethyl isocyanurate) triacrylate, propoxylate glyceryl triacryl , Tetramethylolmethane tetraacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, neopentyl glycol oligoacrylate, 1,4-butanediol oligoacrylate, 1,6- Examples include hexanediol oligoacrylate, trimethylolpropane oligoacrylate, and pentaerythritol oligoacrylate.

  The urethane acrylate oligomer may be an oligomer having a urethane bond in the molecule and having 6 or more (meth) acryloyl groups. The weight average molecular weight of the urethane acrylate oligomer is preferably 600 to 20,000, and more preferably 600 to 10,000. If it exceeds 20,000, there is a risk that the adhesiveness disappearance after irradiation with active energy rays will be insufficient. The urethane acrylate oligomer preferably has 6 to 20 (meth) acryloyl groups in the molecule. When it is less than 6, there is a possibility that the adhesiveness disappearance after irradiation with active energy rays may be insufficient, and even when it exceeds 20, it is difficult to further improve the adhesiveness disappearance after irradiation with active energy rays.

  The photopolymerization initiator (C) is preferably used in an amount of 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the active energy ray-curable compound (B). One type or two or more types of photopolymerization initiators (C) may be used.

  The photopolymerization initiator (C) will be described. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 4-phenylbenzophenone, 4,4-diethylaminobenzophenone, and 3,3-dimethyl-4-methoxybenzophenone. 4-benzoyl-4-methyldiphenyl sulfide, and the like. Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorooxanthone, 2,4-diethylthioxanthone, 1-chloro-4-propoxythioxanthone, and isopropylxanthone. Examples of the acetophenone photopolymerization initiator include 2-methyl-1-[(4-methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4- Morpholinophenyl) -butanone-1,1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1- Phenylpropan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-phenoxydichloroacetophenone, diethoxyacetophenone 1-hydroxycyclohexyl phenyl ketone and the like. Examples of the benzoin photopolymerization initiator include benzoin methyl ether, benzoin isobutyl ether, and benzyl methyl ketal. Examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) acylphosphine oxide, and the like. Examples of bisimidazole initiators include 2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis ( o-chlorophenyl) -4,5,4 ′, 5′-tetra (4-methylphenyl) -1,2′-biimidazole and the like. Examples of the acridine initiator include 1,7-bis (9-acridyl) heptane. Examples of the carbazole-phenone initiator include 3,6-bis (1-keto-2-methyl-2-morpholinopropyl). ) -9-octylcarbazole and triazine photoinitiators include, for example, 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- ( p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6- Bis (trichloromethyl) -s-triazine, 2,4-bis (trichloromethyl) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6 Bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6 -Triazine, 2,4-trichloromethyl (4'-methoxystyryl) -6-triazine and the like. Other examples include oxime initiators.

  It is also preferable to use a photopolymerization initiator (C) and a sensitizer in combination. Examples of the sensitizer include triethanolamine, N-methyldiethanolamine, N, N′-dimethylethanolamine, N-methylmorpholine and the like.

  Examples of active energy rays used in the present invention include electromagnetic waves such as electron beams, ultraviolet rays, and radiation. In the present invention, ultraviolet rays are preferable. Ultraviolet irradiation can be performed using a known light source. The active energy ray irradiation can be performed once or a plurality of times. The integrated dose is not particularly limited as long as the adhesive strength can be reduced after irradiation.

  The active energy ray adhesive strength-removing pressure-sensitive adhesive composition includes a tackifier, a polymerization inhibitor, a plasticizer, a thickener, an antioxidant, an ultraviolet absorber, an infrared absorbing material, a wetting agent, a filler, a pigment, Various known additives such as dyes, diluents, rust inhibitors and curing accelerators may be included. Only one type of these additives may be used, or two or more types may be appropriately used. Moreover, the addition amount of an additive should just be taken as the quantity from which the target physical property is obtained, and is not specifically limited.

  The active energy ray adhesive strength-removing pressure-sensitive adhesive composition of the present invention comprises a base material, a pressure-sensitive adhesive layer (I) formed from the active energy ray adhesive strength-removing pressure-sensitive adhesive composition, and a release sheet. It is preferably used in the form of an adhesive tape. It is preferable that the release treatment surface of the release sheet has irregularities with an arithmetic average roughness (Ra) of 0.10 to 2 μm, and more preferably 0.10 to 1 μm. By providing unevenness on the release treatment surface, a replica of the unevenness is formed on the pressure-sensitive adhesive surface that comes into contact. Therefore, when the adhesive tape is applied, the unevenness formed on the adhesive surface reduces the contact area with the adherend, thereby facilitating reattachment when applying to the CCL insulating layer, for example, polyimide. Here, when the Ra of the release treatment surface is less than 0.10 μm, the contact area with the adherend is large, and it may be difficult to reattach. If it exceeds 2 μm, the unevenness will not be relaxed by the adhesive layer even after sticking, and the unevenness will remain between the CCL / adhesive tape, and the chemical solution will enter there, so that floating / peeling in the process, adhesive residue after peeling or contamination There is a fear. The release sheet is a sheet that is made release by coating the surface of the support with a silicon compound, a fluorine compound, or the like. Here, the arithmetic average roughness (Ra) is defined in JIS B0601-1994, and is an average value of absolute value deviation from the average line. Ra is measured using a surface roughness measuring machine (Dektak ET-4000: manufactured by Beiko Japan Ltd.).

  In addition, when explaining the re-sticking property, when sticking the adhesive tape for reinforcing the CCL, air may be mixed into the CCL / adhesive sheet interface, but in that case, unevenness derived from air occurs in the CCL with the adhesive tape, If the FPC manufacturing process is performed as it is, it is difficult to uniformly treat the CCL sheet as a whole, and defects occur in the formation of conductive circuits and plating in the concavo-convex portion and its periphery. Therefore, when air is mixed, it is necessary to peel the adhesive sheet once so that the air can escape, and then re-paste it. There are a method of dealing with the problem of re-sticking by reducing the adhesive strength of the pressure-sensitive adhesive tape, and a method of improving the air escape during sticking by providing physical unevenness on the adhesive surface. In the former case, if the adhesive strength is set too low in order to give priority to re-sticking, there is a possibility that floating or peeling occurs during the manufacturing process. Therefore, in the present invention, the latter means is taken.

  In the present invention, the base material is preferably a plastic film capable of transmitting active energy rays and having flexibility, and specifically, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). , Polyolefins such as polyethylene, polypropylene, polystyrene, ethylene / vinyl acetate copolymer (EVA), vinyls such as polyvinyl chloride and polyvinylidene chloride, polysulfone, polyethersulfone, polyphenylene sulfide, polycarbonate, polyamide, polyimide, Examples of the film include acrylic resin, triacetyl cellulose, and cycloolefin resin. PET is preferable because it is easily available and handled.

  Since the base material passes through the printed circuit board manufacturing process, the base material preferably has chemical resistance. As for the thickness of a base material, 5-200 micrometers is preferable. When the thickness is less than 5 μm, the handleability is deteriorated, and when it exceeds 200 μm, the flexibility is lost and the handleability is deteriorated. It is also preferable to subject the base material surface on which the pressure-sensitive adhesive layer is formed to easy adhesion treatment in order to improve adhesion. Examples of the easy adhesion treatment include dry treatment such as corona discharge treatment, plasma treatment, and flame treatment, and wet treatment such as primer treatment.

As a method for producing the pressure-sensitive adhesive sheet, for example, the following two methods may be mentioned.
(1): A method in which an active energy ray adhesive strength-removing pressure-sensitive adhesive composition is directly applied to a substrate, dried and cured, and a release treatment surface of a release sheet is bonded.
(2): A method in which an active energy ray adhesive strength-removing pressure-sensitive adhesive composition is applied onto a release-treated surface of a release sheet, dried and cured, and bonded to a substrate.

  Examples of the application method of the active energy ray-adhesive adhesive composition include comma coat, lip coat, curtain coat, blade coat, gravure coat, kiss coat, reverse coat, micro gravure coat, roll, bar coat and screen coat. Etc.

  The thickness of the pressure-sensitive adhesive layer (I) to be formed is preferably about 0.5 μm to 100 μm. When the thickness is less than 0.5 μm, sufficient adhesive physical properties cannot be obtained, and when it exceeds 100 μm, it is economically disadvantageous.

  The release sheet has been subjected to a release treatment on at least one surface thereof, and has an uneven surface on the release treatment surface as described above. For example, paper or plastic film is preferably used as the support. Examples of the method for creating the unevenness include a method of creating by embossing on a release sheet, and a method of applying a release treatment agent to a paper having a desired surface roughness as a support. There is no limitation as long as it is a release sheet having Ra. The thickness of the support is preferably 1 to 200 μm. When it is less than 1 μm, handling becomes difficult, and when it exceeds 200 μm, it is economically disadvantageous.

  The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples, “part” represents “part by weight”.

<Polymer synthesis example 1>
Using 99.3 parts of butyl acrylate, 0.7 part of 2-hydroxyethyl acrylate, 0.1 part of azobisisobutyronitrile and 150 parts of ethyl acetate, the mixture was heated to reflux in a nitrogen atmosphere and polymerized by solution polymerization. Went. As a result, a polymer (A) solution having a hydroxyl group with a nonvolatile content of 40% was obtained. The weight average molecular weight (Mw) of the polymer was 420,000.

<Polymer synthesis example 2>
Nitrogen atmosphere starting from 86.8 parts butyl acrylate, 10 parts methyl acrylate, 3 parts acrylic acid, 0.2 parts 4-hydroxybutyl acrylate, 0.08 parts azobisisobutyronitrile and 212.5 parts ethyl acetate The polymer was synthesized by solution polymerization with heating under reflux. As a result, a polymer (A-1) solution having a carboxyl group having a nonvolatile content of 32% was obtained. The weight average molecular weight of the polymer was 700,000.

<Polymer synthesis example 3>
Heat in a nitrogen atmosphere using 84.7 parts of butyl acrylate, 15 parts of methyl acrylate, 0.3 part of 2-hydroxyethyl methacrylate, 0.06 part of azobisisobutyronitrile, 185 parts of acetone and 169 parts of toluene as raw materials. The polymer was synthesized by solution polymerization. As a result, a polymer (A) solution having a hydroxyl group with a nonvolatile content of 22% was obtained. The weight average molecular weight of the polymer was 1.1 million.

<Polymer synthesis example 4>
Nitrogen atmosphere starting from 85.9 parts butyl acrylate, 10 parts methyl acrylate, 4 parts acrylic acid, 0.1 part 4-hydroxybutyl acrylate, 0.08 part azobisisobutyronitrile and 212.5 parts ethyl acetate The polymer was synthesized by solution polymerization with heating under reflux. As a result, a polymer (A-1) solution having a carboxyl group having a nonvolatile content of 32% was obtained. The weight average molecular weight of the polymer was 680,000.

<Polymer synthesis example 5>
To 100 parts of the polymer (A) solution having a hydroxyl group synthesized in Polymer Synthesis Example 1, 0.32 part of 2-methacryloyloxyethyl isocyanate and 0.00032 part of dibutylhydroxytoluene are added and heated in an oxygen atmosphere to synthesize. went. As a result, a polymer (A) solution having a methacryloyl group in the side chain having a nonvolatile content of 41% was obtained. The weight average molecular weight of the polymer was 440,000.

<Polymer synthesis example 6>
Polymer synthesis was carried out by solution polymerization using 94 parts of butyl acrylate, 6 parts of 2-hydroxyethyl methacrylate, 0.1 part of azobisisobutyronitrile, and 185 parts of ethyl acetate, and heating in an oxygen atmosphere. As a result, a polymer (A) solution having a hydroxyl group with a nonvolatile content of 35% was obtained. The weight average molecular weight of the polymer was 400,000.

<Creation of adhesive sheet>
Using a comma coater, apply the pressure-sensitive adhesive composition, which is stirred and mixed in the composition shown in the upper part of Table 1, to a 100 μm-thick easy-adhesion-treated PET film (U426 Toray) so that the dry film thickness is 20 μm. Then, after passing through a hot air drying oven, the release treatment surfaces of the release sheets shown in the lower part of Table 1 were bonded together to obtain adhesive tapes of Examples 1 to 7 and Comparative Examples 1 to 3 .

  About the adhesive tape obtained by the Example and the comparative example, the physical property measurement of the following item was performed. The measurement results are shown in Table 2.

[Adhesive force]
After applying the adhesive tape and polyimide film (Kapton 100H Toray DuPont) peeled from the release sheet with a hand roller, laminating under conditions of 80 ° C-0.4MPa-1m / min, a tensile tester (manufactured by Tester Sangyo) The following measurements were performed in a T-type peel test (width 25 mm, peel speed 300 mm / min) in accordance with JIS K6854 using “TE-503”).
Adhesive strength 20 minutes after application: Measured 20 minutes after application (unit: N / 25 mm).
Permanent adhesion: measured 24 hours after application.
Adhesive strength after irradiation: Using a high-pressure mercury lamp within 2 hours of application, active energy rays were irradiated until the integrated illuminance reached 500 mJ / cm ² , and the adhesive strength was measured 24 hours after irradiation.

[Pasteability]
The adhesive tape cut to B5 size and peeled off the release sheet was applied to the polyimide film cut to A4 size with a hand roller, and the adhesive tape was peeled off immediately after that, and the peelability was evaluated in 5 stages.
1: There is adhesive residue.
2: There is a dotted adhesive residue.
3: There is peeling sound.
4: No peeling sound.
5: Easy to peel.

[Chemical resistance test]
Since the plating step is performed with an acidic or alkaline aqueous solution, a pH 2 dilute sulfuric acid solution is used on the acidic side and a caustic soda solution pH 11 is used as the evaluation solution.
The test conditions were as follows. Adhesive tape cut to 4 cm in length and 4 cm in width was applied to a polyimide film cut in 6 cm in length and 6 cm in width with a hand roller, and then laminated under the condition of 80 ° C.−0.4 MPa−1 m / min. After immersing in an acidic solution or alkaline solution at 1 ° C. for 1 hour and washing with water, the presence / absence of floating off was visually evaluated in five stages.
1: The adhesive tape was peeled off.
2: A part of the adhesive tape floated.
3: The outer periphery of the adhesive tape swelled.
4: The outer periphery of the adhesive tape slightly swelled.
5: No abnormality.

[Adhesive residue evaluation]
The sample used in the chemical resistance test was irradiated with active energy rays until the integrated illuminance reached 500 mJ / cm ² using a high-pressure mercury lamp after drying. The adhesive tape was peeled off within 1 hour of irradiation, and the adhesive residue on the polyimide surface was visually evaluated in five stages.
1: There is a dotted glue residue.
2: There is adhesive residue on the outer periphery of the adhesive tape.
3: There is adhesive residue on a part of the outer periphery of the adhesive tape.
4: Although peripheral cloudiness is confirmed, there is no adhesive residue.
5: No adhesive residue or contamination.

[Comprehensive evaluation]
From the physical property results of the above four items, it was determined by the XX method whether the adhesive tape can be used in the printed circuit board manufacturing process.
○: Available.
×: Unusable.

  As shown in the physical property results in Table 2, as in Examples 1 to 7, the adhesive tape of the present invention had good re-stickability and chemical resistance and no adhesive residue, whereas Comparative Examples 1 to 4 were attached. There was nothing that satisfied all of the repairability, chemical resistance, and adhesive residue evaluation. It can be said that the adhesive tape coated with the active energy ray adhesive strength-reducing adhesive composition of the present invention is particularly useful as a reinforcing adhesive tape in the production process of electronic circuits, printed circuit boards and the like.

Claims (3)

Polymer (A) having a hydroxyl group obtained by copolymerizing 0.01 to 5 parts by weight of a hydroxyl group-containing monomer and other copolymerizable monomers , an active energy ray-curable compound (B), a photopolymerization initiator (C) and A polymer comprising an isocyanate-based curing agent (D), wherein the equivalent ratio of isocyanate groups in (D) is more than 1 and not more than 30 with respect to the total number of hydroxyl groups of (A) to (C) ( A) 30 to 150 parts by weight of the active energy ray-curable compound (B) is contained with respect to 100 parts by weight of the active energy ray adhesive disappearing pressure-sensitive adhesive composition for producing a printed circuit board . The polymer (A) having a hydroxyl group is a polymer (A-1) further having a carboxyl group, and (A-1), the active energy ray-curable compound (B), and the photopolymerization initiator (C) are 2. The printed circuit board production according to claim 1, wherein an equivalent ratio of the isocyanate group in the isocyanate curing agent (D) to the total of the hydroxyl groups and carboxyl groups is 0.05 to 0.35 . Active energy ray adhesive strength disappearing pressure-sensitive adhesive composition. 3. For printed circuit board production , comprising a base material, an adhesive layer (I) formed from the active energy ray-adhesive adhesive composition for printed circuit board production according to claim 1 or 2, and a release sheet, which are sequentially laminated . An active energy ray adhesive tape for producing a printed circuit board , wherein the adhesive sheet is an active energy ray adhesive strength disappearing type adhesive tape, wherein the release sheet has an arithmetic average roughness (Ra) of 0.10 to 2 μm. Power loss type adhesive tape.