Adhesive precursor composition and method for producing adhesive tape and sheet

Abstract

To provide an adhesive tape capable of smoothly performing an assembling operation even under low temperatures during winter and having heat resistance and to provide an adhesive precursor composition for producing such an adhesive tape.SOLUTION: There is prepared an adhesive precursor composition comprising 100 pts.mass of a copolymerization polymer of an acrylic acid alkyl ester and acrylic acid, 1 to 50 pts.mass of a curable polymer and a crosslinking agent. Here, the curable polymer has a hydrolyzable silyl group in which the main chain is a polyoxyalkylene ether and both terminals of the main chain are represented by -Si(Rn)X3-n [in which, R represents an alkyl group having 1 to 6 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, n represents 0, 1 or 2] and has a urethane bond and / or a urea bond between the main chain and the terminals. A solution is obtained by adding an organic solvent to the adhesive precursor composition, followed by mixing. The solution is applied to a tape base material, followed by forming an adhesive layer by evaporating the organic solvent to obtain an adhesive tape.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive precursor composition used in producing an adhesive tape or sheet (hereinafter, both are collectively referred to as "adhesive tape"). [Background technology]

[0002] Adhesive tapes have traditionally been used when assembling house doors, truck beds, and the like. House doors and the like are exposed to high temperatures in the summer, so heat-resistant adhesive tapes are used. A heat-resistant adhesive tape is one that has high holding power even at high temperatures. The present applicant has proposed the adhesive tape described in Patent Document 1 as a heat-resistant adhesive tape. This adhesive tape is obtained using the following adhesive precursor composition: That is, a copolymer of an alkyl acrylate and acrylic acid of 0.5 to 50 parts by mass, a polyoxyalkylene ether main chain having -Si(R n )X 3-n [wherein R represents an alkyl group having 1 to 6 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, and n represents 0, 1, or 2.], and the curable polymer has a urethane bond and / or a urea bond between the main chain and the terminal, and 5 to 150 parts by mass of a tackifying resin, and the adhesive precursor composition is obtained using a composition that is substantially free of a curing catalyst.

[0003] The present applicant used the heat-resistant adhesive tape described in Patent Document 1 to assemble doors and other items for residential buildings. However, while the assembly work went smoothly in the summer, it sometimes did not go smoothly in the winter. For example, when attempting to bond components of a residential door or other item together, the components sometimes did not adhere well to each other and were prone to peeling during handling. This is because assembly work for residential doors and other items is often carried out outdoors or in factories without air conditioning, and in winter, assembly work is carried out at low temperatures of around 0°C.

[0004] [Patent Document 1] Patent No. 5890737 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a pressure-sensitive adhesive tape that exhibits good adhesion between its constituent members even at low winter temperatures and that is heat-resistant, and to provide a pressure-sensitive adhesive precursor composition for producing such a pressure-sensitive adhesive tape. [Means for solving the problem]

[0006] The present invention solves the above-mentioned problem by reversing the mass ratio of the copolymer and the curable polymer described in Patent Document 1. That is, the present invention provides a copolymer of 100 parts by mass of an acrylic acid alkyl ester and acrylic acid, a main chain of which is a polyoxyalkylene ether and which has -Si(R n )X 3-n [wherein R represents an alkyl group having 1 to 6 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, and n represents 0, 1, or 2.], and the curable polymer has a urethane bond and / or a urea bond between the main chain and the terminal, and a crosslinking agent. The present invention also relates to a method for producing a pressure-sensitive adhesive tape using the pressure-sensitive adhesive precursor composition.

[0007] [About copolymers] The copolymer used in the present invention is a copolymer of a (meth)acrylic acid alkyl ester and (meth)acrylic acid. The term "(meth)acrylic acid" collectively refers to both acrylic acid and methacrylic acid, and may refer to either acrylic acid, methacrylic acid, or a mixture of the two. The same applies to the term "(meth)acrylate." The copolymerization ratio of the (meth)acrylic acid alkyl ester and (meth)acrylic acid is arbitrary, but generally, it is preferable that the ratio of the (meth)acrylic acid alkyl ester to the (meth)acrylic acid is 100 parts by mass: 0.5 to 25 parts by mass, and particularly preferably the ratio of the (meth)acrylic acid alkyl ester to the (meth)acrylic acid is 100 parts by mass: 1 to 15 parts by mass.

[0008] As the (meth)acrylic acid alkyl ester, 2-ethylhexyl (meth)acrylate, 4-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, ethyl (meth)acrylate, or methyl (meth)acrylate can be used alone or in combination. As the (meth)acrylic acid, acrylic acid or methacrylic acid can be used alone or in combination. The copolymer may contain other monomers copolymerized with the (meth)acrylic acid alkyl ester and (meth)acrylic acid. For example, cohesive strength-improving components such as sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, vinyl esters, and aromatic vinyl compounds, as well as components having functional groups that improve adhesive strength or act as crosslinking base points, such as carboxyl group-containing monomers, acid anhydride group-containing monomers, hydroxyl group-containing monomers such as 4-hydroxyethyl acrylate and 2-hydroxyethyl acrylate, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine, and vinyl ethers, can be used as appropriate. The other components can be used alone or in combination of two or more.

[0009] The copolymer is produced by a conventional solution polymerization method or emulsion polymerization method. The weight-average molecular weight of the copolymer is optional, but is generally adjusted to 100,000 to 1,000,000. If the weight-average molecular weight is outside this range, the adhesiveness of the pressure-sensitive adhesive layer tends to decrease or the pressure-sensitive adhesive layer tends to become hard. The weight-average molecular weight of the copolymer is preferably 200,000 to 900,000. The weight-average molecular weight is measured by the GPC method. Specifically, a GPC measurement device "Gel Permeation Chromatography HLC-8220" manufactured by Tosoh Corporation, a developing solvent of THF (tetrahydrofuran), a column "TSKgel Super HZM-H" manufactured by Tosoh Corporation, and polystyrene as a standard substance were used.

[0010] [About curable polymers] The curable polymer used in the present invention has a polyoxyalkylene ether main chain, has hydrolyzable silyl groups represented by the following general formula (1) at both ends of the main chain, and has a urethane bond and / or urea bond between the main chain and the ends. General formula (1); -Si(R n )X 3-n (wherein R represents an alkyl group having 1 to 6 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, and n represents 0, 1, or 2.)

[0011] Such curable polymers are obtained by introducing hydrolyzable silyl groups to the terminals of compounds primarily composed of polyoxyalkylene ethers such as polyoxypropylene glycol, polyoxyethylene glycol, polyoxypropylene triol, polyoxyethylene triol, polyoxyethylene polyoxypropylene glycol, or polyoxyethylene polyoxypropylene triol via urethane and / or urea bonds. The molecular weight of the polyoxyalkylene ether is preferably 3,000 to 100,000, more preferably 5,000 to 90,000, and most preferably 8,000 to 80,000. Curable polymers can be obtained, for example, by bonding a compound having a hydrolyzable silyl group to a polyoxyalkylene ether in which a diisocyanate compound has been partially introduced. Alternatively, they can be obtained by bonding a compound having a hydrolyzable silyl group at one terminal and an isocyanate group at the other terminal to a polyoxyalkylene ether. The curable polymer may be a single type or a mixture of two or more types.

[0012] Representative examples of the curable polymer include polymers having the following structural formulae 1 to 4. [ka] [ka] [ka] [ka] (In Chemical Formulas 1 to 4, Z represents a polyoxyalkylene ether residue, R 2 and R 3 represents an alkyl group having 1 to 20 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, R represents an alkyl group having 1 to 6 carbon atoms, n represents 0, 1 or 2, and m represents a positive number of 2 or more.

[0013] The hydrolyzable silyl groups at both ends of the curable polymer are represented by the general formula (1); -Si(R n )X 3-n (wherein R represents an alkyl group having 1 to 6 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, and n represents 0, 1, or 2.) n is preferably 1. Those in which n is 0 have three hydrolyzable groups at the terminals, but such polymeric compounds tend to have a denser three-dimensional network structure after curing than those in which n is 1, resulting in a harder adhesive layer and poorer ability to conform to bending of the tape or sheet substrate. Those in which n is 2 have only one hydrolyzable group at the terminal, resulting in an insufficient three-dimensional network structure after curing and a tendency for the adhesive layer to be too soft. Furthermore, as can be seen from this, in order to achieve the desired hardness or softness in the adhesive layer, it is sufficient to mix and adjust those in which n is 0, 1, or 2 in a predetermined ratio.

[0014] [About crosslinking agents] As the crosslinking agent, a conventionally known agent can be used, for example, an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent. The isocyanate-based crosslinking agent is not particularly limited as long as it contains two or more isocyanate groups in the molecule, and a conventionally known isocyanate compound can be used. The epoxy-based crosslinking agent is not particularly limited as long as it contains two or more epoxy groups in the molecule, and a conventionally known epoxy compound can be used. These crosslinking agents function as crosslinking aids, auxiliary to promote crosslinking of the copolymer polymer and / or curable polymer, thereby improving the heat resistance and adhesion of the pressure-sensitive adhesive layer.

[0015] [Mixing ratio of copolymer and curable polymer] The blending ratio of the copolymer and the curable polymer is 1 to 50 parts by mass of the curable polymer per 100 parts by mass of the copolymer. If the blending ratio of the curable polymer is less than 1 part by mass, the heat resistance of the pressure-sensitive adhesive layer decreases, which is not preferred. If the blending ratio of the curable polymer exceeds 50 parts by mass, the adhesion of the pressure-sensitive adhesive layer to the adherend at low temperatures decreases, which is not preferred. The blending ratio of the crosslinking agent is preferably 1 to 5 parts by mass per 100 parts by mass of the copolymer. If the blending ratio of the crosslinking agent is less than 1 part by mass, the heat resistance of the pressure-sensitive adhesive layer decreases, which is not preferred. If the blending ratio of the crosslinking agent exceeds 5 parts by mass, the heat resistance of the pressure-sensitive adhesive layer becomes saturated.

[0016] [Other ingredients] A tackifying resin may be blended into the pressure-sensitive adhesive precursor composition as desired. Examples of the tackifying resin include known tackifying resins used in producing pressure-sensitive adhesives. Examples include rosin-based resins such as rosin, polymerized rosin, hydrogenated rosin, and rosin ester; terpene-based resins such as terpene phenolic resins, aromatic-modified terpene resins, hydrogenated terpene resins, and rosin phenolic resins; aliphatic petroleum resins; aromatic petroleum resins; various hydrogenated petroleum resins such as aromatic hydrogenated petroleum resins, dicyclopentadiene hydrogenated petroleum resins, and aliphatic hydrogenated petroleum resins; coumarone-indene resins; styrene-based resins; maleic acid-based resins; alkylphenol resins; and xylene resins. In particular, in the present invention, terpene-based resins such as terpene phenolic resins and styrene-based resins are preferably used. The blending ratio of the tackifying resin may be any; for example, about 1 to 20 parts by mass may be blended per 100 parts by mass of the copolymer. Furthermore, the following compounds or substances may be added and mixed. For example, an antioxidant, a dehydrating agent, a filler, a plasticizer, a diluent, a flame retardant, a pigment, etc. may be added and mixed in. In the pressure-sensitive adhesive precursor composition according to the present invention, the curable polymer is cured by moisture in the atmosphere to form a pressure-sensitive adhesive layer, so there is no need to blend a curing catalyst for curing the curable polymer.

[0017] [Adhesive precursor composition] The pressure-sensitive adhesive precursor composition is prepared by uniformly mixing a copolymer, a curable polymer, and a crosslinking agent. If necessary, a tackifying resin and the like are also mixed at this time. Because mixing the components promotes curing and crosslinking reactions, they are mixed immediately before the production of the pressure-sensitive adhesive tape. Therefore, when providing the pressure-sensitive adhesive precursor composition of the present invention to pressure-sensitive adhesive tape manufacturers, it is provided as a kit consisting of two or three parts. Specifically, it is provided as two parts: one part mainly composed of a copolymer and including a crosslinking agent, and another part including a curable polymer. Alternatively, it is provided as a three-part kit, optionally with the crosslinking agent as a separate part. When uniformly mixing the copolymer, curable polymer, and crosslinking agent, an organic solvent is generally added to adjust the viscosity. Examples of organic solvents that can be used include alcohols such as ethanol, ethyl acetate, toluene, and methylcyclohexane. The amount of organic solvent added is generally 50 to 100 parts by mass per 100 parts by mass of the pressure-sensitive adhesive precursor composition.

[0018] [About the manufacturing method of adhesive tape] A pressure-sensitive adhesive tape can be obtained by applying a pressure-sensitive adhesive precursor composition to a tape substrate and curing the composition to form a pressure-sensitive adhesive layer. In the present invention, the pressure-sensitive adhesive tape is preferably obtained by the following method. First, as described above, an organic solvent is added to the pressure-sensitive adhesive precursor composition to prepare a uniformly mixed solution. The organic solvent is added to adjust the viscosity to facilitate application to the tape substrate. Examples of tape substrates that can be used include metal foils such as aluminum foil, synthetic resin films such as polyester, various foams such as polyether foams such as polypropylene glycol, acrylic foams, polyethylene foams, and polyurethane foams, and various nonwoven fabrics. In the present invention, aluminum foil, heat-resistant polyester film, polyether foams, or acrylic foams (acrylic foams) with excellent heat resistance are preferably used. The solution containing the pressure-sensitive adhesive precursor composition can be applied to one surface or both surfaces of the tape substrate. In the latter case, a double-sided pressure-sensitive adhesive tape is obtained. Furthermore, the solution containing the pressure-sensitive adhesive precursor composition can be applied by a conventionally known method, such as a knife coater method or a roll coater method. Furthermore, the thickness of the applied solution containing the pressure-sensitive adhesive precursor composition is the same as that of the conventional one, that is, about 5 to 200 μm.

[0019] After application, the solution is heated in the atmosphere. The heating temperature is preferably 40 to 150°C, and more preferably 80 to 150°C. This heating evaporates the organic solvent in the solution. Furthermore, the hydrolyzable silyl groups of the curable polymer are partially condensed by the moisture in the atmosphere, forming a three-dimensional network structure and partially curing the solution. Then, by curing at room temperature, the curing proceeds and a pressure-sensitive adhesive layer is formed. The curing of this curable polymer is accelerated by the carboxylic acid groups introduced into the copolymer. That is, although the pressure-sensitive adhesive precursor composition according to the present invention does not contain a curing catalyst, the copolymer functions as a conventional curing catalyst. Furthermore, by mixing a crosslinking agent, the copolymer crosslinks, forming a tighter three-dimensional network structure and curing the solution to form a pressure-sensitive adhesive layer. In this manner, a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on one or both sides of a tape substrate can be produced.

[0020] The pressure-sensitive adhesive tape obtained by the above method can be used for various conventional applications. In particular, it has excellent low-temperature adhesion and heat resistance, and can be used as a fixing pressure-sensitive adhesive tape for assembling house doors, truck beds, etc. in winter. [Effects of the Invention]

[0021] The pressure-sensitive adhesive precursor composition according to the present invention contains 100 parts by mass of a copolymer, 1 to 50 parts by mass of a curable polymer, and a crosslinking agent, and the curable polymer is cured by atmospheric moisture. The pressure-sensitive adhesive layer obtained by curing contains a larger amount of copolymer than curable polymer, and therefore has excellent adhesion to an adherend even at low winter temperatures. Furthermore, since the curable polymer is cured, it also has excellent heat resistance. In other words, a pressure-sensitive adhesive tape obtained using the pressure-sensitive adhesive precursor composition according to the present invention exhibits the effect of possessing both heat resistance and adhesion to an adherend at low temperatures. [Example]

[0022] [Copolymer Synthesis Example 1] A reactor equipped with a stirrer was charged with 95 parts by weight of 2-ethylhexyl acrylate (2-EHA), 5 parts by weight of acrylic acid (AA), and 0.5 parts by weight of 4-hydroxybutyl acrylate (4-HBA) in 100 parts by weight of ethyl acetate as a polymerization solvent. The mixture was heated to 80°C under a nitrogen atmosphere and refluxed for 1 hour. A solution of 0.1 parts by weight of azobisisobutyronitrile (AIBN) dissolved in 20 parts by weight of ethyl acetate was then added dropwise over 1 hour. The reaction was continued for another 6 hours at 80°C under a nitrogen atmosphere, yielding a transparent, uniform copolymer (1) with a solids concentration of 45%. The weight-average molecular weight (Mw) of this copolymer (1) was 253,000, the ratio of Mw to number-average molecular weight (Mn) (Mw / Mn) was 3.0, and the acid value was 17.6.

[0023] [Copolymer Synthesis Example 2] A reactor equipped with a stirrer was charged with 45 parts by weight of 2-ethylhexyl acrylate (2-EHA), 50 parts by weight of n-butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), and 0.5 parts by weight of 4-hydroxybutyl acrylate (4-HBA) in 100 parts by weight of ethyl acetate as a polymerization solvent. The mixture was heated to 80°C under a nitrogen atmosphere and refluxed for 1 hour. A solution of 0.1 parts by weight of azobisisobutyronitrile (AIBN) dissolved in 20 parts by weight of ethyl acetate was then added dropwise over 1 hour. The reaction was continued for another 6 hours at 80°C under a nitrogen atmosphere, yielding a transparent, uniform copolymer (2) with a solids concentration of 45%. The weight-average molecular weight (Mw) of this copolymer (2) was 485,000, the ratio of Mw to number-average molecular weight (Mn) (Mw / Mn) was 4.4, and the acid value was 17.6.

[0024] [Copolymer Synthesis Example 3] A reactor equipped with a stirrer was charged with 90 parts by weight of 2-ethylhexyl acrylate (2-EHA), 10 parts by weight of acrylic acid (AA), and 0.5 parts by weight of 4-hydroxybutyl acrylate (4-HBA) in 100 parts by weight of ethyl acetate as a polymerization solvent. The mixture was heated to 80°C under a nitrogen atmosphere and refluxed for 1 hour. A solution of 0.1 parts by weight of azobisisobutyronitrile (AIBN) dissolved in 20 parts by weight of ethyl acetate was then added dropwise over 1 hour. The reaction was continued for another 6 hours at 80°C under a nitrogen atmosphere, yielding a transparent, uniform copolymer (3) with a solids concentration of 45%. The weight-average molecular weight (Mw) of this copolymer (3) was 350,000, the ratio of Mw to number-average molecular weight (Mn) (Mw / Mn) was 1.6, and the acid value was 35.0.

[0025] [Synthesis Example 4 of Comparative Copolymer] Comparative copolymer (4) was obtained in the same manner as in Copolymer Synthesis Example 2, except that acrylic acid (AA) was not used. The weight-average molecular weight (Mw) of this comparative copolymer (4) was 382,000, the ratio (Mw / Mn) of the weight-average molecular weight to the number-average molecular weight (Mn) was 5.8, and the acid value was 0.0.

[0026] [Curable Polymer Synthesis Example 1] First, a silylating agent was obtained by the following method. A reaction vessel was charged with 222 parts by mass of N-aminoethyl-3-aminopropyldimethoxysilane and 172 parts by mass of methyl acrylate, and the mixture was reacted at 80°C for 10 hours while stirring under a nitrogen atmosphere to obtain a silylating agent. In this silylating agent, the hydrolyzable silyl group and the nitrogen atom of the nitrogen-containing bond are bonded via a propylene group, and the nitrogen atom is further bonded via an ethylene group to a nitrogen atom constituting the nitrogen-containing bond in a different environment. Meanwhile, 1,000 parts by mass of Preminol S4015 (polyoxypropylene diol, molecular weight 15,000: manufactured by AGC Inc.), 26.6 parts by mass of isophorone diisocyanate (NCO / OH ratio = 1.7), and 0.05 parts by mass of dioctyltin dilaurate were charged into a reaction vessel, and the mixture was reacted at 85°C for 5 hours while stirring and mixing under a nitrogen atmosphere, to obtain a urethane prepolymer whose main chain was mainly polyoxypropylene and in which urethane bonds had been introduced into the main chain. 38.9 parts by mass of the silylating agent was added to 1000 parts by mass of this urethane prepolymer, and the mixture was stirred and mixed under a nitrogen atmosphere at 80°C for 1 hour to give a curable polymer (1). -1 The progress of the reaction was confirmed by the disappearance of . This curable polymer (1) is represented by Chemical Formula 1 and / or Chemical Formula 2, has a hydrolyzable silyl group (X=methoxy group, n=1), and Z is a residue of polyoxypropylene with some urethane bonds introduced.

[0027] [Curable Polymer Synthesis Example 2] Except for using N-aminoethyl-3-aminopropyltrimethoxysilane instead of N-aminoethyl-3-aminopropyldimethoxysilane, a curable polymer (2) was obtained in the same manner as in Curable Polymer Synthesis Example 1. This curable polymer (2) is represented by Chemical Formula 1 and / or Chemical Formula 2, has a hydrolyzable silyl group (X = methoxy group, n = 0), and Z is a residue of polyoxypropylene with some urethane bonds introduced.

[0028] [Preparation of Pressure-Sensitive Adhesive Precursor Composition and Production of Pressure-Sensitive Adhesive Sheet] Example 1 A solution containing a pressure-sensitive adhesive precursor composition was obtained by uniformly mixing 100 parts by mass of copolymer (1), 15.6 parts by mass of curable polymer (1), and 2 parts by mass of an isocyanate compound (Takenate D101E (45EA) manufactured by Mitsui Chemicals, Inc., solids concentration 45%) in a stirring vessel. This solution containing the pressure-sensitive adhesive precursor composition was applied to one surface of a 25 μm-thick polyester film using a knife coater so that the coating thickness after drying would be approximately 50 μm. The solution was then heated at 100°C for 3 minutes to evaporate the solvent and partially cure the curable polymer (1), yielding a film having a pressure-sensitive adhesive layer on one side. To ensure complete curing of the pressure-sensitive adhesive layer, the solution was further aged at 40°C for 3 days to obtain a pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer was laminated on one side of a polyester film.

[0029] Example 2 An adhesive tape was obtained in the same manner as in Example 1, except that the amount of curable polymer (1) was changed to 46.7 parts by mass to obtain a solution containing an adhesive precursor composition.

[0030] Example 3 An adhesive tape was obtained in the same manner as in Example 1, except that 5 parts by mass of rosin ester ("Pensel D135" manufactured by Arakawa Chemical Industries, Ltd.) was added as a tackifier resin to obtain a solution containing an adhesive precursor composition.

[0031] Example 4 A solution containing a pressure-sensitive adhesive precursor composition was obtained in the same manner as in Example 1, except that 0.09 parts by mass of an epoxy compound (Tetrad C manufactured by Mitsubishi Gas Chemical Company, Inc.) was blended in place of 2 parts by mass of an isocyanate compound (Takenate D101E (45EA) manufactured by Mitsui Chemicals, Inc., solid content concentration 45%). Thereafter, a pressure-sensitive adhesive tape was obtained in the same manner as in Example 1.

[0032] Example 5 An adhesive tape was obtained in the same manner as in Example 1, except that copolymer (2) was used instead of copolymer (1) and the blending ratio of the isocyanate compound ("Takenate D101E (45EA)" manufactured by Mitsui Chemicals, Inc., solid content concentration 45%) was changed to 1 part by mass to obtain a solution containing an adhesive precursor composition.

[0033] Example 6 An adhesive tape was obtained in the same manner as in Example 1, except that the copolymer (3) was used instead of the copolymer (1) to obtain a solution containing an adhesive precursor composition.

[0034] Example 7 An adhesive tape was obtained in the same manner as in Example 1, except that the amount of the curable polymer (1) was changed to 1.6 parts by mass to obtain a solution containing an adhesive precursor composition.

[0035] Example 8 An adhesive tape was obtained in the same manner as in Example 1, except that the solution containing the adhesive precursor composition was obtained by using the curable polymer (2) instead of the curable polymer (1).

[0036] Example 9 An adhesive tape was obtained in the same manner as in Example 1, except that a tape substrate made of a polyether foam obtained by the manufacturing method described below was used instead of the 25 μm thick polyester film, and a solution containing an adhesive precursor composition was applied to both sides of the tape substrate. [Method of manufacturing tape substrate] First, the following raw materials were uniformly mixed to prepare a mixture. 100 parts by mass of vinyl group-containing polymer with a polypropylene glycol skeleton (Kaneka Corporation "ACS009A") Hydrophobic silica 2 parts by mass (Aerosil R974 manufactured by Nippon Aerosil Co., Ltd.) Plastic balloons 10 parts by mass ("EMC-40(B)" manufactured by Nippon Phillite Co., Ltd.) 20 parts by weight of calcium carbonate ("NS2300" manufactured by Nitto Funka Kogyo Co., Ltd.) Hydrosilyl group-containing compound 5.6 parts by mass (Kaneka Corporation "CR500") Dimethyl maleate (Tokyo Chemical Industry Co., Ltd.) 0.01 parts by mass This mixture was applied to a release paper using an applicator to a thickness of 0.4 mm, and then cured by heat treatment in an oven at 120°C for 10 minutes to obtain a tape substrate with a thickness of 0.4 mm.

[0037] Comparative Example 1 A solution containing a pressure-sensitive adhesive precursor composition was obtained in the same manner as in Example 1, except that the curable polymer (1) was not blended. Thereafter, a pressure-sensitive adhesive tape was obtained in the same manner as in Example 1.

[0038] Comparative Example 2 A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that a solution containing a pressure-sensitive adhesive precursor composition was obtained by using comparative copolymer (4) instead of copolymer (1). However, the pressure-sensitive adhesive layer of this pressure-sensitive adhesive tape was not sufficiently cured, and it was not suitable for testing.

[0039] Comparative Example 3 An adhesive tape was obtained in the same manner as in Example 1, except that the amount of the curable polymer (1) was changed to 60 parts by mass to obtain a solution containing an adhesive precursor composition.

[0040] [Adhesion test at low temperatures] The 180° peel adhesive strength (N / 25 mm) of each of the pressure-sensitive adhesive tapes obtained in Examples 1 to 9 and Comparative Examples 1 to 3 at 0°C was measured by the following method. First, a 30 mm wide, 150 mm long stainless steel plate (SUS304) polished with #280 waterproof abrasive paper was prepared as an adherend. Separately, a 25 mm wide, 150 mm long strip-shaped test piece (sample tape) was taken from each pressure-sensitive adhesive tape. Each sample tape was attached to a surface-polished adherend in a 0°C environment, and after aging for 1 minute, the adhesive strength (N / 25 mm) was measured when the tape was peeled off in a 180° direction from the adherend using a tensile tester. The pulling speed was 300 mm / min. The results of the 180° peel adhesive strength (N / 25 mm) are shown in Table 1.

[0041] [Heat resistance test] The holding power at 80°C of each of the pressure-sensitive adhesive tapes obtained in Examples 1 to 9 and Comparative Examples 1 to 3 was measured by the following method. First, a 30 mm wide, 100 mm long stainless steel plate (SUS304) polished with #280 waterproof abrasive paper was prepared as an adherend. Separately, a 25 mm wide, 100 mm long strip-shaped test piece (sample tape) was taken from each pressure-sensitive adhesive tape, and the pressure-sensitive adhesive layer surface of a 25 mm area (25 mm × 25 mm) from the edge was attached to the adherend. Immediately after attachment, the test piece was left in an 80°C oven, with the adhesive tape-attached side facing downward. A 1 kg weight was hung in the shear direction, and the adhesive tape was observed every hour for peeling from the adherend. Peeling after 1 hour was evaluated as 1 hour or less, peeling after 2 hours was evaluated as 2 hours or less, and peeling after 24 hours or more was evaluated as 24 hours or more. The results are shown in Table 1.

[0042] [Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Adhesion test at low temperatures Heat resistance test ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 11.3 More than 24 hours Example 2 8.3 More than 24 hours Example 3 10.5 24 hours or more Example 4 12.5 24 hours or more Example 5 9.0 More than 24 hours Example 6 10.3 More than 24 hours Example 7 5.3 More than 24 hours Example 8 4.5 More than 24 hours Example 9 11.5 More than 24 hours Comparative Example 1 8.8 1 hour or less Comparative example 2 Uncured Uncured Comparative Example 3 2.0 24 hours or more ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0043] As can be seen from the results in Table 1, the pressure-sensitive adhesive tapes obtained in Examples 1 to 9 showed good results in both the adhesion test at low temperatures and the heat resistance test. On the other hand, the pressure-sensitive adhesive tape obtained in Comparative Example 1 had poor heat resistance because the pressure-sensitive adhesive layer was obtained without blending a curable polymer. The pressure-sensitive adhesive tape obtained in Comparative Example 2 did not contain acrylic acid as a structural unit in the copolymer, so the pressure-sensitive adhesive layer was not cured and could not be used. Furthermore, the pressure-sensitive adhesive tape obtained in Comparative Example 3 had a low blend ratio of the copolymer, so it had poor adhesion at low temperatures and was difficult to use for assembling doors and the like for houses in winter.

Claims

1. 100 parts by mass of a copolymer of an alkyl (meth)acrylate and (meth)acrylic acid, 1 to 50 parts by mass of a curable polymer whose main chain is a polyoxyalkylene ether, which has hydrolyzable silyl groups represented by the following general formula (1) at both ends of the main chain, and which has a urethane bond and / or a urea bond between the main chain and the ends, A pressure-sensitive adhesive precursor composition containing a crosslinking agent. General formula (1); -Si(R n )X 3-n (wherein R represents an alkyl group having 1 to 6 carbon atoms, X represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, and n represents 0, 1, or 2.)

2. 2. The pressure-sensitive adhesive precursor composition according to claim 1, wherein the copolymerization ratio of the (meth)acrylic acid alkyl ester to the (meth)acrylic acid is (meth)acrylic acid alkyl ester:(meth)acrylic acid=100 parts by mass:1 to 15 parts by mass.

3. The pressure-sensitive adhesive precursor composition according to claim 1, further comprising a tackifier resin.

4. 2. The pressure-sensitive adhesive precursor composition according to claim 1, wherein the crosslinking agent is an isocyanate compound and / or an epoxy compound.

5. A method for producing an adhesive tape or sheet, comprising: adding an organic solvent to the adhesive precursor composition according to claim 1 and uniformly mixing the resulting solution; applying the resulting solution to a tape or sheet substrate; heating the resulting solution in the atmosphere to evaporate the organic solvent; and curing the curable polymer to form an adhesive layer.

6. The method for producing an adhesive tape or sheet according to claim 5, wherein the curable polymer is cured by curing at room temperature or under heat.

7. 10. A pressure-sensitive adhesive tape or sheet comprising a tape or sheet substrate and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive precursor composition according to claim 1 on one or both sides of the substrate.

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