KR101917906B1 - Adhesive tape - Google Patents

Abstract

A pressure-sensitive adhesive tape for use in fixing an optical film, wherein the pressure-sensitive adhesive layer in contact with the optical film is a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive composition in an aqueous dispersion, the pressure-sensitive adhesive layer has a glass transition temperature of -5 DEG C or less, A pressure-sensitive adhesive tape capable of appropriately fixing a member even when an aqueous pressure-sensitive adhesive in which VOC is reduced by an adhesive tape having a thickness of 45 to 45% is used, and deformation of the optical film, which is prone to deformation, can be suppressed. INDUSTRIAL APPLICABILITY The adhesive tape of the present invention has excellent environmental responsiveness and can suppress peeling of the adhesive tape due to deformation such as twisting of the case and decrease in visibility due to deformation of the optical film even when the optical film is to be adhered to , It is suitable for fixation between components of an image display apparatus to which an optical film is to be adhered, particularly for fixing an optical film and a transparent panel.

Description

Adhesive Tape {ADHESIVE TAPE}

The present invention relates to an adhesive tape for fixing an optical film used in an image display apparatus such as a liquid crystal display or an organic EL (Electro Luminescence) display.

2. Description of the Related Art Image display devices such as a liquid crystal display are used in a wide range of fields including a word processor and a personal computer. Particularly in an electronic notebook, a mobile phone, a PHS, a smart phone, a game device, Have been used. In these image display devices, a configuration in which a backlight module and a display panel such as an LCD panel mounted on the surface thereof are fixed by an adhesive tape in an image display module such as an LCD module is widely used, An optical film such as a prism sheet is often provided.

For example, in a sidelight type backlight type liquid crystal display, a reflection plate, a light guide plate, a diffusion sheet and the like are generally laminated, an optical film such as a prism sheet is provided on the surface layer, and an LED A back light module in which a light source such as a light emitting diode (LED) and a cold cathode tube are disposed, and an LCD panel are stacked. Between the LCD panel and the backlight module, a double-sided pressure-sensitive adhesive tape (normally punched in a frame, whose width is usually about 0.5 mm to about 10 mm) is inserted. The double-sided adhesive tape may be in contact with only the prism sheet on the surface layer of the backlight module, or may be in contact with the prism sheet on the surface layer of the backlight module and the light body containing the backlight module. And also has a role of fixing the seat and the like, preventing the penetration of dust and cushioning, and also preventing the cracks of the respective parts due to the impact.

In addition, in the adhesive tape, it is strongly demanded to block the leakage light from the light source or effectively use the light, so that the light shielding property and the light reflection property are combined. Such adhesive tapes have been conventionally studied for the purpose of improving properties, and disclose an adhesive tape for an LCD module that has a light-shielding property and a light reflectivity in a thin shape (see Patent Document 1).

In recent years, however, with the adhesive tape used in the area, problems that have not been posed in the related art are rising due to high performance of the electronic devices to be used, in particular, thinning and versatility of mobile phones. One of them is the thinning of the inner member according to the thinning of the multifunctional cellular phone. However, when the optical film fixing the periphery with the double-sided adhesive tape by the thinning of the optical film is left at high temperature in the reliability test, deformation of the optical film occurs There is a problem that When the light passes through the deformed portion, the image in the LCD panel becomes lacking in sharpness. Such a problem occurs particularly remarkably in accordance with the increase in the size of a portable electronic terminal such as a smart phone or a tablet-type terminal. On the other hand, an adhesive tape for suppressing deformation of an optical film has been proposed, and an attempt has been made to fix deformation of an optical film while fixing the parts between them well (see Patent Documents 2 to 3).

On the other hand, from the viewpoint of the environment, in recent years, the peripheral materials of these image display devices have also been required to be changed to a material in which VOC (Volatile Organic Compound) is reduced. In particular, It has been expected that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is also changed from a solvent-based pressure-sensitive adhesive to an aqueous pressure-sensitive adhesive. For this reason, it has been desired to realize an adhesive tape using an aqueous adhesive which is capable of satisfactorily securing the parts between the components and capable of suppressing deformation of the optical film preferably. In addition, in order to suppress peeling of the adhesive tape due to distortion of the terminal due to the large-sized surface of the portable electronic terminal, it is also desired to improve the fixability of components, particularly the resistance to repulsion.

Japanese Patent Laid-Open No. 2004-156015 Japanese Patent Laid-Open No. 2008-248226 Japanese Patent Application Laid-Open No. 2010-168437

Disclosure of the Invention An object of the present invention is to provide a pressure-sensitive adhesive tape for fixing an optical film which tends to be deformed, which can fix a member preferably even when an aqueous pressure- Tape. ≪ / RTI >

In the present invention, it is preferable that the pressure-sensitive adhesive layer used for fixing the optical film is a pressure-sensitive adhesive layer in contact with the optical film, the pressure-sensitive adhesive layer comprising an aqueous dispersion type acrylic pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer has a glass transition temperature of -5 DEG C or less, The above problem can be solved by the adhesive tape having a thickness of 25 to 45%.

The pressure-sensitive adhesive tape of the present invention uses a pressure-sensitive adhesive layer having a glass transition temperature of -5 占 폚 or less and a gel fraction of 25 to 45% as a pressure-sensitive adhesive layer on the side to be attached to the optical film, It is possible to securely fix the parts therebetween, to have good anti-repulsion property, and to suppress the deformation of the optical film appropriately. Therefore, it is possible to suppress detachment of the adhesive tape due to deformation such as twist of the case, or the like due to reduction in visibility due to deformation of the optical film, even when the optical film is to be adhered, , And is suitable for fixation between components of an image display device to which an optical film is to be adhered, particularly for fixing an optical film and a transparent panel.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a conceptual diagram showing a method for measuring the deformation preventing property of an optical film in an embodiment. Fig.
2 is a conceptual diagram showing a method of measuring the resistance to repulsion in the embodiment.

The pressure-sensitive adhesive tape according to the present invention is an adhesive tape used for fixing an optical film, wherein the pressure-sensitive adhesive layer in contact with the optical film is a pressure-sensitive adhesive layer containing an aqueous acrylic pressure-sensitive adhesive composition, The fraction is 25 to 45%.

[Pressure sensitive adhesive layer]

In the pressure-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive layer applied to the optical film is a pressure-sensitive adhesive layer formed from an aqueous acrylic pressure-sensitive adhesive composition in which acrylic copolymer emulsion particles are dispersed in an aqueous medium. In the present invention, the flexibility of the pressure-sensitive adhesive is sufficiently secured by setting the glass transition temperature (Tg) of the pressure-sensitive adhesive layer to -5 deg. C or lower, preferably -10 deg. C or lower, more preferably -15 deg. Thus, even when deformation occurs in the optical film, deformation can be suppressed while appropriately following the deformation. Further, the pressure sensitive adhesive is sufficiently wetted on the adherend to ensure adhesion between the adherend and the pressure sensitive adhesive, and appropriate anti-repulsion property can be realized.

The glass transition temperature of the pressure-sensitive adhesive layer constituting the adhesive tape of the present invention is the peak temperature of the loss tangent (tan?) Of the dynamic viscoelastic spectrum. The measurement of the dynamic viscoelasticity can be carried out, for example, by using a viscoelasticity tester (Ares 2KFRTN1, manufactured by Rheometrics Co., Ltd.) and sandwiching a test piece between parallel discs, The storage elastic modulus (G ') and the loss elastic modulus (G' ') at temperatures ranging from 0 to 150 ° C are measured.

tan? = G? / G?

The pressure sensitive adhesive having a thickness of 0.5 to 2.5 mm may be sandwiched between the parallel discs, but the laminate of the substrate and the pressure sensitive adhesive may be repeatedly sandwiched between the parallel discs. In the latter case, the peak temperature of the loss tangent of the dynamic viscoelastic spectrum of the pressure-sensitive adhesive is not affected even when the substrate is sandwiched in between.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive layer having a gel fraction of 25 to 45%. By setting the gel fraction of the pressure-sensitive adhesive layer within the above range at the glass transition temperature, it is possible to secure flexibility to exhibit sufficient wettability and adhesion to the adherend, and to secure a cohesive force capable of withstanding stress, Can be satisfactorily restrained and an appropriate rebound resisting property can be realized. The gel fraction is a gel fraction expressed as mass ratio before and after immersion after measuring the insoluble matter after immersing the pressure-sensitive adhesive layer in toluene for 24 hours.

The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer having a glass transition temperature and a gel fraction. The glass transition temperature of the pressure-sensitive adhesive layer is determined by the glass transition temperature of the acrylic copolymer, the glass transition temperature, And the like. The gel fraction can be appropriately adjusted depending on the amount of the crosslinking agent or crosslinking agent to be added to the pressure-sensitive adhesive composition, and the amount of the functional group monomer or functional group monomer to be introduced into the acrylic copolymer reacting with the crosslinking agent.

(Acrylic copolymer)

As the aqueous dispersion type acrylic pressure-sensitive adhesive composition for use in the pressure-sensitive adhesive layer, a composition in which emulsion particles of an acrylic copolymer are dispersed in an aqueous medium can be used. The acrylic copolymer preferably has a glass transition temperature measured by a dynamic viscoelastic spectrum of -45 캜 to -25 캜, more preferably -40 캜 to -30 캜. By setting the glass transition temperature of the acrylic copolymer within the range, flexibility of the pressure-sensitive adhesive can be sufficiently ensured. Accordingly, even if deformation occurs in the optical film, deformation can be easily suppressed while appropriately following the deformation. Further, when the pressure-sensitive adhesive is sufficiently wetted on the adherend, adhesion between the adherend and the pressure-sensitive adhesive is easily ensured, and it is easy to realize adequate anti-repulsion property.

The glass transition temperature of the acrylic copolymer constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape of the present invention is the peak temperature of the loss tangent (tan?) Of the dynamic viscoelastic spectrum. In the measurement of the dynamic viscoelasticity, a sheet containing only an acrylic copolymer can be prepared and measured in the same manner as the pressure-sensitive adhesive layer.

As the (meth) acrylate monomer used in the acrylic copolymer, a (meth) acrylate monomer used in a pressure-sensitive adhesive can be appropriately used, and among these, a (meth) acrylate monomer having an alkyl group having 4 to 8 carbon atoms, Can be preferably used. Examples of the (meth) acrylate monomer having 4 to 8 carbon atoms include n-butyl (meth) acrylate, isobutyl (meth) acrylate, t- (Meth) acrylate such as isooctyl (meth) acrylate, n-octyl (meth) acrylate and the like can be used. Among them, n-butyl acrylate and / or 2-ethylhexyl acrylate can be preferably used, and 2-ethylhexyl acrylate is particularly preferable since it is easy to control the glass transition temperature of the resulting pressure-sensitive adhesive layer to a low level. Further, compatibility with the tackifier resin is apt to be improved, and improvement in adhesion with the substrate and the adherend can be easily obtained.

The content of the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms is preferably 50 to 98% by mass, particularly preferably 80 to 98% by mass, in the monomer components used in the acrylic copolymer. By setting the content of the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms within the range, the flexibility of the pressure-sensitive adhesive can be sufficiently secured. Accordingly, even if deformation occurs in the optical film, deformation can be easily suppressed while appropriately following the deformation. Further, when the pressure-sensitive adhesive is sufficiently wetted on the adherend, adhesion between the adherend and the pressure-sensitive adhesive is easily ensured, and it is easy to realize adequate anti-repulsion property.

When 2-ethylhexyl acrylate which can be particularly preferably used is used, it is preferably 40% by mass or more, more preferably 60% by mass or more, of the monomer components used in the acrylic copolymer, More preferably 80% by mass or more, and still more preferably 90% by mass or more. By setting it in the range, the flexibility of the pressure-sensitive adhesive can be sufficiently secured. Accordingly, even if deformation occurs in the optical film, deformation can be easily suppressed while appropriately following the deformation.

In the present invention, other (meth) acrylate monomers may be used in combination as the (meth) acrylate monomers for forming the acrylic copolymer. Examples of the (meth) acrylate monomer other than the above include (meth) acrylate monomers such as methyl (meth) acrylate and ethyl (meth) acrylate, Can be used together. Among them, (meth) acrylate having an alkyl group having 2 or less carbon atoms such as methyl (meth) acrylate and ethyl (meth) acrylate is preferably used in combination, and the amount thereof is preferably 1 to 10% by mass.

In the present invention, it is preferable to use a carboxyl group-containing monomer in order to increase the cohesive force within the acrylic copolymer emulsion particle or between the particles. As the carboxyl group-containing monomer, one or more kinds selected from carboxyl group-containing vinyl monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, phthalic acid, phthalic anhydride, crotonic acid and the like can be used. Among them, acrylic acid and methacrylic acid are advantageous in that cohesive force is easily ensured by interaction between carboxyl groups, a large number of crosslinking agents to be reacted and a high cohesive strength are provided, and interaction with nitrogen-containing vinyl monomers to be described later can be expressed .

The content of the carboxyl group-containing monomer is preferably 0.5 to 10% by mass, preferably 0.5 to 5% by mass, more preferably 1.5 to 3.5% by mass, based on the monomer component forming the acrylic copolymer. By making the ratio fall within the above range, the crosslinking reaction with the crosslinking agent tends to proceed well. Further, cohesive force capable of withstanding stress can be easily ensured, deformation of the optical film can be suppressed well, and an appropriate rebound resistance can be easily realized.

)하는 효과를 만들어 낸다고 추찰된다. 질소 함유 비닐 단량체의 함유량은 0.1 내지 4.5질량％, 바람직하게는 0.5 내지 4질량％, 보다 바람직하게는 0.5 내지 3.5질량％이다.In the present invention, it is preferable to use a nitrogen-containing vinyl monomer as the monomer component of the acrylic copolymer. The nitrogen-containing vinyl monomer interacts with an acid group, particularly a carboxyl group, in the acrylic copolymer emulsion particle, so that a carboxyl group, which is easily oriented on the particle surface,

). The content of the nitrogen-containing vinyl monomer is 0.1 to 4.5 mass%, preferably 0.5 to 4 mass%, and more preferably 0.5 to 3.5 mass%.

As the nitrogen-containing vinyl monomer, a nitrogen-containing monomer having an amide group can be preferably used. The nitrogen-containing monomer having an amide group is not excessively strong with respect to the acid group, as compared with the amine-based nitrogen-containing monomer group, can adequately maintain the cohesive force in the emulsion particle and the interaction between the particles, It becomes easy to get rid of, so that it becomes easy to obtain adequate adhesion and reworkability. Examples of the nitrogen-containing monomer having an amide group include at least one member selected from the group consisting of N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylonitrile, acrylamide and N, N- Two or more species can be used.

The ratio of the nitrogen-containing vinyl monomer to the carboxyl group-containing vinyl monomer in the acrylic copolymer is not particularly limited, but the mole number of the nitrogen-containing vinyl monomer in the monomer component constituting the acrylic copolymer is X, the mole number of the vinyl monomer having a carboxyl group is Y Is preferably from 1/1 to 1/20, more preferably from 1/1 to 1/5, and further preferably from 1/1 to 1/3. Within this range, the reaction between the vinyl monomer having a carboxyl group and a crosslinking agent described later tends to proceed.

In the acrylic copolymer used in the present invention, monomers other than the above may be used if necessary. Examples of such monomers include (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydro Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like can be appropriately used. Examples of the monomer having a keto group or an aldehyde group include diacetone acrylamide, diacetone methacrylamide, acrolein, formylstilhole, vinylmethylketone, vinylethylketone, vinylisobutylketone, diacetone acrylate, diacetone methacrylate, Nitrile acrylate, 2-hydroxypropyl acrylate acetoacetate, butanediol acrylate acetate, and the like. Examples of the silane-based monomer include 3-methacryloxypropylmethyldimethoxysilane (for example, KBM-502 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltrimethoxysilane (KBE-502 manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., (For example, KBE-503 manufactured by Shin-Etsu Chemical Co., Ltd.) and 3-acryloxypropyltrimethoxysilane (for example, KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.). As the methylol group-containing monomer, N-methylol acrylamide and the like can be given. Examples of the phosphoric acid group-containing monomer include Sipomer PAM-100, PAM-200 and PAM-300 manufactured by Rhodia K.K., and 20% by mass or more of a monomer component forming an acrylic copolymer, Or less, and they may be used alone or in combination of two or more.

The weight average molecular weight of the acrylic copolymer used in the present invention is preferably from 50 to 120,000, more preferably from 60 to 1,000,000. By making the ratio fall within the above range, the flexibility of exhibiting sufficient wettability and adhesiveness to the adherend is improved, and on the other hand, the cohesive force capable of enduring the stress is improved, whereby the deformation of the optical film can be satisfactorily suppressed, . The weight average molecular weight is a standard polystyrene conversion by gel permeation chromatography (GPC). As a measurement condition, the column is TSKgel GMHXL (manufactured by Tosoh Corporation), the column temperature is 40 占 폚, the eluent is tetrahydrofuran, the flow rate is 1.0 ml / min, and the standard polystyrene is TSK standard polystyrene.

In order to adjust the molecular weight, a chain transfer agent may be used for polymerization. Examples of the chain transfer agent include known chain transfer agents such as lauryl mercaptan, glycidylmercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3- 1-propanol and the like can be used.

(Tackifier resin)

In the acrylic-based pressure-sensitive adhesive composition for use in the present invention, it is preferable to use a tackifier resin in order to exhibit sufficient wettability and adhesiveness to an adherend and to improve cohesive force capable of withstanding stress. The glass transition temperature of the tackifier resin is preferably 30 to 120 캜, more preferably 40 to 100 캜, still more preferably 45 to 80 캜, still more preferably 50 to 60 캜. By blending a tackifying resin having a glass transition temperature higher than that of the acrylic copolymer, the tackiness is improved.

The glass transition temperature of the pressure-sensitive adhesive resin used in the pressure-sensitive adhesive constituting the pressure-sensitive adhesive tape of the present invention is preferably such that the glass transition temperature of the glass transition point of JIS K 7121 in the stepwise change portion of the glass transition of the DSC curve measured by the DSC measuring apparatus It is the temperature specified as the temperature. As a specific measuring method, for example, a DSC curve measured by using a DSC measuring apparatus (manufactured by Mettler-Toledo Co., Ltd., product name: DSC822) is analyzed by using the software attached to the apparatus. The sample is dried in a vacuum dryer at 60 ° C for 2 days or more under vacuum. The range of -50 ° C to 200 ° C is measured twice continuously at a heating rate of 2 ° C / min, and the second measurement data is analyzed to calculate the glass transition temperature.

As the tackifier resin used in the present invention, an emulsion-type tackifier resin can be preferably used from the viewpoint of use in an aqueous dispersion type pressure-sensitive adhesive composition. Examples of the emulsion-type tackifier resin include rosin, polymerized rosin, polymerized rosin ester, rosin phenol, stabilized rosin ester, disproportionated rosin ester, terpene, terpene phenol, petroleum resin and the like .

Among them, it is preferable to use a polymerized rosin ester-based tackifying resin and / or a rosin-phenol-based tackifying resin. Specifically, the polymerized rosin ester-based tackifying resin is a mixture of Super Ester E-650 (manufactured by Arakawa Chemical Industries Ltd.), Super Ester E-788 (manufactured by Arakawa Chemical Industries, Ltd.), Super Ester E-786 -60 (manufactured by Arakawa Chemical Industries, Ltd.), Superester E-865 (manufactured by Arakawa Chemical Industries, Ltd.), Superester E-865 NT (manufactured by Arakawa Chemical Industries, Ltd.) (Harima Kasei Co., Ltd.), Hariesta SK-508H (manufactured by Harima Kasei Corporation), Hariesta SK-816E (manufactured by Harima Kasei Corporation), Hariesta SK-822E (Manufactured by Arakawa Chemical Industries, Ltd.), Hariesta SK-323NS (manufactured by Harima Kasei K.K.), and the rosin ester-based tackifying resin is Super Stear NS-125A Ester NS-100H (manufactured by Arakawa Chemical Industries, Ltd.), Hariesta SK-90D-55 (manufactured by Harima Kasei Corporation) The modified rosin ester-based tackifying resin is Hariesta SK-501NS (manufactured by Harima Kasei Co., Ltd.), Hariesta SK-370N (manufactured by Harima Kasei Co., Ltd.) (Available from Arakawa Chemical Industries, Ltd.), Superester NS-100A (manufactured by Arakawa Chemical Industries, Ltd.), and the like can be cited as the rosin-based tackifier resin (Manufactured by Arakawa Chemical Industries, Ltd.), Tamanol E-200 (manufactured by Arakawa Chemical Industries, Ltd.), Tamanol E-200NT [manufactured by Arakawa Chemical Industries, Ltd.] Manufactured by Arakawa Chemical Industries, Ltd.] and the like.

The ratio of the acrylic copolymer / the tackifier resin to the acrylic copolymer / tackifier resin is preferably 100/10 to 100/40, more preferably 100/15 To 100/35. Within this range, sufficient wettability to the adherend, the appearance of the adhesion, and the cohesive force capable of withstanding stress can be balanced well.

(Crosslinking agent)

In the acrylic-based pressure-sensitive adhesive composition for use in the present invention, it is preferable to use a crosslinking agent for the purpose of improving the cohesive force of the obtained pressure-sensitive adhesive layer. As the crosslinking agent, known crosslinking agents such as isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, polyvalent metal salt crosslinking agents, metal chelating crosslinking agents, keto-hydrazide crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, Epoxysilane crosslinking agents, and the like can be used. Among them, a crosslinking agent of the type which is added after the polymerization is completed and the crosslinking reaction proceeds is preferable. Examples thereof include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, a carbodiimide crosslinking agent, and a glycidyl (alkoxy) epoxy silane crosslinking agent. Specific examples of the isocyanate crosslinking agent include BAROX DNW-5000 (manufactured by DIC Corporation), BAROX DNW-5010 (manufactured by DIC Corporation), BAROX DNW-5100 (Manufactured by Nippon Polyurethane Industry Co., Ltd.), Arcanate 105 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Arcanate 100 (manufactured by Nippon Polyurethane Industry Co., Ltd.) , Arcanate 120 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Arcanate 130 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Arcanate 200 (manufactured by Nippon Polyurethane Industry Co., Ltd.) (Manufactured by Sumitomo Bayer Urethane Co., Ltd.), LS2336 (manufactured by Sumitomo Bayer Urethane Co., Ltd.) and Bayhydur 3100 (manufactured by Sumitomo Bayer Urethane Co., Ltd.) Epoxy-based crosslinking agents include Denacol EX-832 (manufactured by Nagase Kasei Kogyo Co., Ltd.), Denacol EX-841 , Tetrad C (manufactured by Mitsubishi Gas Chemical Co., Ltd.), tetrad X (manufactured by Mitsubishi Gas Chemical Company), and the like. Examples of the oxazoline crosslinking agent include Epocross WS-500 (Manufactured by Nippon Shokubai Co., Ltd.), Epochros WS-700 (manufactured by Nippon Shokai Kabushiki Kaisha), Epochros K-2010E (manufactured by Nippon Shokubai Co., Ltd.), Epochros K-2020E (Manufactured by Nippon Shokubai Co., Ltd.), Carbodite SV-02 (manufactured by Nisshinbo Industries, Ltd.), Carbodite V- 02, manufactured by Nisshinbo Industries, Ltd., Carbodite V-02-L2 [manufactured by Nisshinbo Industries, Ltd.], Carbodite V- Carbodite E-02 (manufactured by Nisshinbo Industries, Ltd.), Carbodite E-03A (manufactured by Nisshinbo Industries, Ltd.), Carbodite E-04 ], Glycidyl (alkoxy) epoxy silane type Examples of the 2- (3,4-epoxycyclohexyl ethyl trimethoxy silane [KBM-303; Shin-Etsu Silicone Co., Ltd.),? -Glycidoxypropyltrimethoxysilane (KBM-403; Shin-Etsu Silicone Co., Ltd.),? -Glycidoxypropylmethyldiethoxysilane (KBE-402; Shin-Etsu Silicone Co., Ltd.),? -Glycidoxypropyltriethoxysilane (KBE-403; Manufactured by Shin-Etsu Silicone Co., Ltd.].

Among them, it is preferable to use a crosslinking agent which reacts with the vinyl monomer having an acid group, and the isocyanate crosslinking agent, the epoxy compound, the oxazoline compound, the carbodiimide crosslinking agent, the glycidyl (alkoxy) epoxy silane compound and the like are preferable Do. By using a cross-linking agent which reacts with these acid groups, it is possible to appropriately express the improvement of the cohesive force.

(additive)

In the aqueous dispersion type acrylic pressure-sensitive adhesive composition for use in the present invention, additives such as a base (ammonia water or the like) for adjusting the pH, a plasticizer, a softener, an antioxidant, Known ones such as fillers such as glass or plastic fibers, balloons, beads or metal powders, coloring agents such as pigments and dyes, pH adjusting agents, film forming auxiliaries, leveling agents, thickening agents, water repellents and defoaming agents may optionally be added to the pressure- have.

The thickness of the pressure-sensitive adhesive layer is preferably 5 to 50 占 퐉, more preferably 10 to 30 占 퐉. When the thickness is 5 mu m or more, sufficient adhesiveness can be obtained. When the thickness is 50 mu m or less, it can be suitably applied to a display device in which thinning and thinning are progressed.

[Support]

The support used in the present invention is not particularly limited, and various supports used for fixing members around the image display apparatus can be used. The support may be, for example, a support containing only a resin film or a support provided with a colored layer on a resin film. In order to achieve good light-shielding performance and light reflection performance, it is necessary to fix the optical film and other members, particularly, to fix the optical film and the transparent panel, Can be preferably used.

As the resin film used for the support, a known resin film can be used, and examples thereof include cellophane, polyethylene, polypropylene, nylon, polystyrene, polyimide and polyester. Among them, polyester can be preferably used because it has excellent strength and insulation. Also, polyethylene terephthalate can be preferably used because it has good adhesion with an ink layer using a polyurethane resin.

The thickness of the resin film as a support is preferably 6 to 100 mu m. When the thickness is 6 mu m or more, fragmentation of the film at the time of peeling is difficult to occur. When the thickness is 100 mu m or less, separation at the time of attaching to an adherend is difficult. More preferably 12 to 50 占 퐉.

Further, the resin film itself may be colored in white or black, and if the resin film is a white resin film having light reflectivity, it is preferable because the brightness of the image display can be increased when the resin film is used in the image display section of the image display apparatus. Among them, white polyethylene terephthalate having insulating property and light diffusing reflectivity is most preferable. Further, if the resin film is a black resin film having light shielding property, it is preferable to increase the contrast of the image display device. Among them, black polyethylene terephthalate is preferred because it can impart excellent light-shielding properties.

When a colored layer is provided on these resin films, it is preferable to use a colored ink. The colored ink used for the colored layer can be suitably used as a colored ink used for a coloring tape such as a light-shielding tape or a light reflection tape used for fixing members around an image display apparatus. Among them, it is particularly preferable that the halogen content of the colored layer is 0.3 mass% or less, preferably 0.05 mass% or less, and substantially contains no halogen. Such a colored layer in which the halogen content is reduced is difficult to obtain anchoring of the pressure-sensitive adhesive layer because a coloring ink which does not use halogen or sulfur-containing resin such as vinyl chloride-based resin is used as the binder resin, When the adhesive strength of the layer is high, it is difficult to obtain the reworkability. However, in the above-mentioned pressure-sensitive adhesive layer used in the present invention, appropriate adhesion and reworkability can be realized even in the colored layer having a low halogen content. Here, the halogen content is a detection amount when analyzed by fluorescent X-ray. For example, examples of analyzers for fluorescent X-rays include "ZSX Primus" and "ZSX Primus II" manufactured by Rigaku Corporation.

As the coloring ink having a reduced halogen content, a coloring ink which does not use a halogen- or sulfur-containing resin such as a vinyl chloride-based resin as a binder resin can be preferably used. As such binder resin, for example, polyurethane resin, polyester resin, polyamide resin, acrylic resin, nitrocellulose and the like can be used. Among them, a polyurethane resin can be preferably used from the viewpoint of adhesion with the pressure-sensitive adhesive layer and adhesion with the resin film laminated with the colored layer, and a polyester urethane resin can be particularly preferably used.

When a polyester urethane resin is used as the binder resin, the glass transition temperature of the polyester urethane resin is preferably -30 캜 to 30 캜, more preferably -20 캜 to 30 캜, More preferably 25 deg. C, and particularly preferably -10 deg. C to 25 deg. When the peak temperature of tan 隆 of the polyester urethane resin is within this range, since the colored layer has appropriate flexibility and hardness, it is difficult to cause fragmentation due to generation of cracks in the colored layer at the time of rewiring, The separation due to heat is less likely to occur.

The glass transition temperature of the polyester urethane resin is defined as the glass transition temperature of the peak tan δ of the dynamic viscoelastic spectrum at a frequency of 1 Hz measured below.

The polyester urethane resin is formed into a thickness of 50 탆 by a bar coater. Next, a test piece (sample length: 20 mm, film thickness: 50 탆) cut into a sample length of 20 mm was measured at a frequency of 1 Hz and a temperature rise time of 3 캜 for 1 minute using a viscoelasticity tester, ) And the loss elastic modulus (G ") are measured. The loss tangent tan delta is calculated from the following equation.

Loss tangent tan? = G '/ G "

Examples of the viscoelasticity tester include DMS210, DMS220 and DMS6100 manufactured by Seiko Instruments.

The coloring ink used for the coloring layer contains a curing agent used in ordinary ink, and it is also preferable that the curing agent contains an aliphatic or alicyclic isocyanate curing agent. By crosslinking a polyester urethane having a glass transition temperature of -30 占 폚 to 30 占 폚 and an aliphatic or alicyclic isocyanate forming a relatively flexible crosslinking structure, it is easy to control the modulus of elasticity, and the ink interface due to the flow of ink at high temperature and the pressure- The peeling of the interface can be suppressed easily. Moreover, since it is easy to obtain an appropriate modulus of elasticity, cracks of the ink layer are hard to enter at the time of rewiring, and the effect that the tape is hardly fragmented is easily obtained.

Examples of the aliphatic or alicyclic isocyanate include hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, trimethylhexamethylene isocyanate, 1,6,11-undecane triisocyanate, lysine diisocyanate, lysine ester triisocyanate, 8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate, and bicycloheptane triisocyanate. In addition, trimers of these isocyanates can be preferably used, and among them, adducts of diisocyanate, burette or nourate are preferred. Among them, an adduct of hexamethylene diisocyanate or isophorone diisocyanate, a burette or a nylate is preferable because it is easy to control the modulus of elasticity, and a burette or a nylate is particularly preferable. The curing agent may be added alone, or two or more kinds of curing agents may be added.

As the coloring agent for coloring the colored ink, known pigments or dyes containing no halogen may be used. In the case of black, carbon black, white, titanium oxide, calcium carbonate, barium sulfate, yellow iron oxide, Cyanine blue in the case of enemy, cyanine blue in the case of blue, aluminum powder in the case of silver, and titanium oxide powder in the case of pearl are preferable from the viewpoint of weatherability, heat resistance and dispersibility to the ink resin. When the colored layer is a light-shielding layer, it is preferable that a black ink layer can be formed, and carbon black is preferable because of its excellent light shielding property. When the colored layer is a light reflecting layer, it is preferable that a white ink layer can be formed, and titanium oxide can be preferably used.

The amount of the colorant to be added can be suitably adjusted in accordance with the application and the like, and is preferably 10 to 70% of the solid content of the ink containing the colorant. More preferably, it is 40 to 50%. If it is 10% or more, the light shielding property is suitably exhibited, and if it is 70% or less, dispersion is good.

The thickness of the colored layer can be appropriately adjusted in accordance with desired characteristics. For example, when the colored layer is used as the light-shielding layer, 1 to 10 mu m is preferable, and 3 to 7 mu m is more preferable from the viewpoints of light shading and workability at the time of tape punching. Further, the thicker the ink, the more preferable the ink layer has a low elastic modulus from the standpoint of reworkability.

The colored layer may be a single layer, but may be laminated in two or more layers depending on desired hiding properties, light reflectivity, and light shielding properties. Particularly, in the case of using the colored layer as the light shielding layer, it is preferable to provide two or more colored layers in order to improve the light shielding property and to prevent light leakage by the pinhole.

In the case where the colored tape of the present invention is a light-shielding tape or a light-shielding reflective tape, the light transmittance when the support is irradiated with light of 10000 cd / m 2 is preferably 1 cd / m 2 or less, and more preferably 0.1 cd / m 2 or less.

[Adhesive tape]

The adhesive tape of the present invention is an adhesive tape for fixing an optical film, and is a pressure-sensitive adhesive tape provided with the above-described pressure-sensitive adhesive layer to be attached to an optical film on at least one surface of a support. With this configuration, it is possible to appropriately fix the optical film which is likely to be deformed while having excellent environmental responsiveness due to the reduction of the VOC, to have good anti-repulsion property, and to suppress the deformation of the optical film appropriately .

The adhesive tape may be a one-sided adhesive tape provided with a pressure-sensitive adhesive layer on one side of a support or a double-sided pressure-sensitive adhesive tape provided with pressure-sensitive adhesive layers on both sides of a support. In fixing between the components, Sided adhesive tape. It is also preferable that the pressure-sensitive adhesive layer applied to the optical film has the same adhesiveness with respect to various adherends, particularly transparent panels such as glass panels. Each of the pressure-sensitive adhesive layers may be a single-layer pressure-sensitive adhesive layer, a plurality of pressure-sensitive adhesive layers laminated, or a plurality of pressure-sensitive adhesive tapes laminated. Further, when the one-sided adhesive tape is used for fixing between parts, it is also applicable to fixing between parts by a method of providing a separate double-sided adhesive tape on the surface having no adhesive layer or a method of applying an adhesive.

The pressure-sensitive adhesive layer can be formed on a resin film or a light-shielding layer by a method generally used for applying an adhesive tape. Specifically, it can be formed by, for example, directly applying a composition for forming a pressure-sensitive adhesive layer on a support followed by drying, or by once applying the composition on a separator, drying and bonding the support to the support.

The thickness of the adhesive tape of the present invention is preferably 20 to 100 占 퐉, more preferably 30 to 75 占 퐉. Of these, particularly preferably from 40 to 65 mu m. The thickness can be suitably used for fixing parts of an image display apparatus, particularly for an image display apparatus of a small electronic apparatus.

The 180-degree peel adhesion force of the adhesive tape of the present invention to the optical film and glass is preferably 7 to 15 N / 20 mm, more preferably 8 to 13 N / 20 mm. When the adhesive force is in the appropriate range, the parts can be fixed properly when the parts of the image display device are fixed.

The content of the halogen (chlorine, bromine, fluorine, iodine) in the adhesive tape of the present invention is preferably 0.3 mass% or less, more preferably 0.05 mass% or less, and particularly preferably substantially no halogen Do. The adhesive tape with reduced halogen is suitable for suppressing the malfunction of the image display device.

As an embodiment of the pressure-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive layer may be provided on the support at least as a pressure-sensitive adhesive layer to be pasted on the optical film. In particular, A structure having a pressure-sensitive adhesive layer can be preferably used. As a preferable specific example, a form having a pressure-sensitive adhesive layer on both sides of a support having a colored layer on one side of a resin film, a form having a pressure-sensitive adhesive layer on both sides of a support having a colored layer on both sides of the resin film, and the like. In these forms, when the colored layer is a light-shielding layer containing black ink, a light-reflecting tape including a white ink as a light-shielding tape can be used as a light-reflecting tape. Further, a resin film which is used in combination of two or a combination thereof is combined with a light-reflecting layer including a light-shielding layer containing a black ink or a white ink by using a light-reflecting white film or a light-blocking black film, You can also use tape.

[Usage]

The double-faced pressure-sensitive adhesive tape of the present invention is used for fixation of an optical film and fixation of an optical film and another member, and is used by affixing a pressure-sensitive adhesive layer formed from the water-dispersible acrylic pressure-sensitive adhesive composition to an optical film. The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having an appropriate adhesion to an adherend and capable of restraining the deformation of the optical film even after the optical film is deformed after the optical film is fixed to the other member. Is suitable for an image display apparatus which requires fixing of In addition, it has good adhesiveness and is particularly excellent in anti-repulsion property. Therefore, a thin image display device in which the optical film is easily deformed, the fixing of the optical film of the image display apparatus tends to cause peeling of the adhesive tape due to deformation such as twist of the case, It can be suitably used as a component fixing tape used for fixing an optical film of the present invention. It is also suitable to use as a light-shielding tape, a light-reflecting tape, and a light-shielding reflective tape for fixing an optical film and a transparent panel of a thin image display device requiring appropriate shading reflection performance and requiring reworkability at the time of failure or repair .

Examples of the optical film include a prism sheet, a diffusion film, a light shielding film, and a reflection film. Among them, a prism sheet in which a prism layer is provided on a film having a polarizing reflection function is particularly exemplified as an optical film susceptible to deformation. Examples of such an optical film include BEF-RP2RC and BEF-RP3 manufactured by 3M Company.

The double-sided pressure-sensitive adhesive tape of the present invention can appropriately suppress the deformation of the optical film, and particularly exhibits an appropriate deformation suppressing effect for an optical film having a size of about 2.5 to 7 inches (diagonal) .

As the change rate of the external shape of the optical film becomes larger, deformation tends to occur, and deformation increases when the behavior changes in the flow direction and the width direction. Especially in the case of a rate of change greater than + 0.05% in the direction of flow or width, especially a rate of change greater than + 0.06% in the direction of flow and greater than -0.06% in the direction of width. With the adhesive tape of the present invention, deformation of the optical film can be suppressed. The appearance change rate of the optical film is represented by the following equation before and after standing at 85 캜 for 5 minutes.

The ratio of appearance change = [(post-post-post-post-post-postal length) / (postal postal length)] x 100 (%

When the optical film has the prism layer and the ridgeline of the prism layer crosses obliquely with the flow direction of the adhesive tape, the optical film is easily deformed. However, the adhesive tape of the present invention can appropriately suppress deformation even in the above- .

The other member to be fixed to the optical film by the double-faced pressure-sensitive adhesive tape of the present invention may be various members that are fixed to the optical film in the image display apparatus. For example, a liquid crystal (LCD) panel, A light emitting panel, a plasma display panel, and an electronic paper display panel. These display panels may be used alone or in combination with a functional film such as a polarizing film. In the double-sided pressure-sensitive adhesive tape of the present invention, when both sides of the pressure-sensitive adhesive layer are made of the above-described acrylic pressure-sensitive adhesive composition of the present invention, adhesion to a glass panel or a polarizing film is particularly excellent.

The mode of fixing the optical film and the other member is not particularly limited as far as the image display region of the image display apparatus can be secured. Preferably, the optical film and the other member are fixed by a double- In which a region around the end of two or more sides of the rectangular optical film is fixed by a double-sided adhesive tape having a rectangular shape, or a double-sided adhesive tape of small pieces on an arbitrary gap in the region around the end of the rectangular optical film And the like can be exemplified.

As an example of an image display apparatus, there is a backlight type LCD. As a general structure thereof, a reflection plate, a light guide plate, a diffusion sheet, and the like are laminated, an optical film such as a prism sheet is provided on the surface layer, and a lamp reflector A backlight module in which light sources such as a LED (light emitting diode) and a cold cathode tube are arranged, and a display panel (LCD panel) are stacked in this order. The adhesive tape of the present invention can be exemplified as a preferred embodiment in which the display panel and the optical film on the surface layer of the backlight module are sandwiched and punched into a frame. The form in which the double-sided pressure-sensitive adhesive tape is applied may be a form in which the pressure-sensitive adhesive layer on the optical film side of the double-sided pressure-sensitive adhesive tape is in contact with only the optical film of the backlight module surface layer, It may be in the form of touching.

The double-sided adhesive tape for fixing a glass panel optical film of the present invention can be applied to various electronic apparatuses, in particular, electronic notebooks, mobile phones, smart phones ), A PHS, a game machine, an electronic book, a multifunctional data terminal, a mobile personal computer, and the like.

Example

[Production Example of Polyester Urethane]

(Polyester urethane resin (A))

A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introducing tube was charged with an acid component having adipic acid / terephthalic acid = 50/50 and a number average molecular weight ), And 36.5 parts of isophorone diisocyanate were charged, and the mixture was reacted at 90 DEG C for 15 hours in a stream of nitrogen. Subsequently, 5.0 parts of isophorone diamine, 2.2 parts of di-n-butylamine, 175 parts of toluene, 350 parts of methyl ethyl ketone and 175 parts of isopropylene alcohol were added and reacted at 40 DEG C for 3 hours under stirring to obtain a resin solid concentration of 30.0% (A) having a Gardner viscosity of UV (25 占 폚), an amine value of 0, and a mass average molecular weight (hereinafter referred to as Mw) of 67,000. The peak temperature of tan? Of the obtained resin was -8 占 폚.

[Production example of black ink]

(Production Example 1 of Black Ink)

40 parts of a polyester urethane resin (A) (tan δ peak temperature = -8 ° C), 4 parts of "Carbon Degussa Special 4A" manufactured by Degussa Corporation, 6 parts of "Carbon Special 250P" 23 parts of toluene, 6 parts of ethyl acetate, 3 parts of N-propyl acetate and 3 parts of isopropyl alcohol were added and wet dispersed in a sand mill for about 1 hour to prepare a curing agent " KR90 " 4 parts of burette of methylene diisocyanate) and 35 parts of a diluent " Dyereser V No. 20 " manufactured by DIC were added to prepare a black ink (A). Further, the resin shows a solid content ratio.

[Production of Support]

(Ink coating film (A))

Corona treatment was carried out on a Tefax FW2 # 13 (thickness: 13 탆, tensile strength 23 N / 20 mm) manufactured by DAIJIN DUPONT FILM CO., LTD. Such that the surface state was 50 dynes or more, 2 < / RTI > The drying was carried out at room temperature for 2 minutes. Thereafter, it was cured at 40 DEG C for 2 days to obtain an ink coating film (A).

[Production method of acrylic copolymer emulsion]

(Production Example 1)

≪ Preparation of emulsion (1) >

75.0 g of ion-exchanged water and 100 g of a surfactant Aquaron KH-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; Active ingredient 25%] and 20.0 g of surfactant Latte PD-104 [manufactured by Kao Corporation; 37.5 g of active ingredient 20%] were added and dissolved homogeneously. Thereto were added 227.5 g of n-butyl acrylate, 227.5 g of 2-ethylhexyl acrylate, 25.0 g of methyl methacrylate, 7.5 g of N-vinylpyrrolidone, 1.5 g of acrylic acid, 11.0 g of methacrylic acid, Was added and emulsified to obtain 632.7 g of the emulsion (1).

≪ Preparation of Emulsion of Acrylic Copolymer (1)

340 g of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel, and the temperature was raised to 60 DEG C while blowing nitrogen therein. 5.0 g of an aqueous solution of ammonium persulfate (active ingredient: 3%) and 5.0 g of an aqueous sodium hydrogen sulfite solution (active ingredient: 3%) were added to the emulsion (1) . Subsequently, 629.5 g of the remaining emulsion (1) and 40 g of ammonium persulfate aqueous solution (active ingredient: 1.25%) were dropwise added and polymerized in the respective funnels over 8 hours while maintaining the reaction vessel at 60 캜. After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 캜, and the contents were cooled. Subsequently, ammonia water (active ingredient 10%) was prepared so as to have a pH of 7.5. This was filtered through a 200-mesh wire netting to obtain 1013.5 g of an emulsion of the acrylic copolymer (1). The emulsion of the obtained acrylic copolymer (1) had a solid concentration of 50% and an average particle diameter of 341 nm.

(Production Example 2)

≪ Preparation of Emulsion (2) >

75.0 g of ion-exchanged water and 100 g of a surfactant Aquaron KH-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; Active ingredient 25%] and 20.0 g of surfactant Latte PD-104 [manufactured by Kao Corporation; 37.5 g of active ingredient 20%] were added and dissolved homogeneously. Thereafter, 227.5 g of n-butyl acrylate, 227.5 g of 2-ethylhexyl acrylate, 25.0 g of methyl methacrylate, 7.5 g of N-vinylpyrrolidone, 12.5 g of acrylic acid and 0.20 g of lauryl mercaptan were emulsified , And 632.7 g of the emulsion (2).

≪ Preparation of Emulsion of Acrylic Copolymer (2)

340 g of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel, and the temperature was raised to 60 DEG C while blowing nitrogen therein. 5.0 g of the aqueous solution of ammonium persulfate (active ingredient: 3%) and 5.0 g of sodium hydrogen sulfite aqueous solution (active ingredient: 3%) were added to the emulsion (2) . Subsequently, 629.5 g of the remaining emulsion (2) and 40 g of ammonium persulfate aqueous solution (active ingredient: 1.25%) were dropwise added and polymerized for 8 hours while maintaining the reaction vessel at 60 ° C using respective funnels. After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 캜, the contents were cooled, and then ammonia water (active ingredient 10%) was prepared so as to have a pH of 7.5. This was filtered through a 200-mesh wire netting to obtain 1013.5 g of an emulsion of the acrylic copolymer (2). The emulsion of the obtained acrylic copolymer (2) had a solid concentration of 50% and an average particle diameter of 338 nm.

(Production Example 3)

≪ Preparation of emulsion (3) >

The vessel was charged with 75.0 g of ion-exchanged water and 100 g of a surfactant AQUALON KH-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) Active ingredient 25%] and 20.0 g of surfactant Latte PD-104 [manufactured by Kao Corporation; 37.5 g of active ingredient 20%] were added and dissolved homogeneously. Thereafter, 50.0 g of n-butyl acrylate, 405.0 g of 2-ethylhexyl acrylate, 25.0 g of methyl methacrylate, 7.5 g of N-vinylpyrrolidone, 12.5 g of acrylic acid and 0.20 g of lauryl mercaptan were emulsified , And 632.7 g of the emulsion (3).

≪ Preparation of Emulsion of Acrylic Copolymer (3)

In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer and a dropping funnel, 340 g of ion-exchanged water was added and the temperature was raised to 60 캜 while nitrogen was blown. 5.0 g of an aqueous solution of ammonium persulfate (active ingredient: 3%) and 5.0 g of sodium hydrogen sulfite aqueous solution (active ingredient: 3%) were added to the emulsion (3) . Subsequently, 629.5 g of the remaining emulsion (1) and 40 g of an aqueous ammonium persulfate solution (active ingredient: 1.25%) were dropwise added and polymerized for 8 hours while maintaining the reaction vessel at 60 ° C using respective funnels. After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 캜, the contents were cooled, and then ammonia water (active ingredient 10%) was prepared so as to have a pH of 7.5. This was filtered through a 200 mesh wire netting to obtain 1013.5 g of an emulsion of the acrylic copolymer (3). The emulsion of the obtained acrylic copolymer (3) had a solid concentration of 50% and an average particle diameter of 330 nm.

(Adjustment example 4)

≪ Preparation of emulsion (4) >

75.0 g of ion-exchanged water and 100 g of a surfactant Aquaron KH-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; Active ingredient 25%] and 20.0 g of surfactant Latte PD-104 [manufactured by Kao Corporation; 37.5 g of active ingredient 20%] were added and dissolved homogeneously. Thereafter, 231.25 g of n-butyl acrylate, 231.25 g of 2-ethylhexyl acrylate, 25.0 g of methyl methacrylate, 1.5 g of acrylic acid, 11.0 g of methacrylic acid and 0.2 g of lauryl mercaptan were added and emulsified to obtain an emulsion 4).

≪ Preparation of Emulsion of Acrylic Copolymer (4)

340 g of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel, and the temperature was raised to 60 DEG C while blowing nitrogen therein. 5.0 g of an aqueous solution of ammonium persulfate (active ingredient: 3%) and 5.0 g of sodium hydrogen sulfite aqueous solution (active ingredient: 3%) were added to the emulsion (4) while stirring at room temperature for 1 hour . Subsequently, 629.5 g of the remaining emulsion (2) and 40 g of ammonium persulfate aqueous solution (active ingredient: 1.25%) were dropwise added and polymerized for 8 hours while maintaining the reaction vessel at 60 ° C using respective funnels. After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 캜, the contents were cooled, and then ammonia water (active ingredient 10%) was prepared so as to have a pH of 7.5. This was filtered through a 200 mesh wire netting to obtain 1013.5 g of an emulsion of the acrylic copolymer (4). The emulsion of the obtained acrylic copolymer (4) had a solid concentration of 50% and an average particle diameter of 345 nm.

(Adjustment example 5)

≪ Preparation of emulsion (5) >

75.0 g of ion-exchanged water and 100 g of a surfactant Aquaron KH-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; Active ingredient 25%] and 20.0 g of surfactant Latte PD-104 [manufactured by Kao Corporation; 37.5 g of active ingredient 20%] were added and dissolved homogeneously. Thereto were added 240 g of n-butyl acrylate, 240 g of 2-ethylhexyl acrylate, 7.5 g of N-vinylpyrrolidone, 1.5 g of acrylic acid, 11.0 g of methacrylic acid and 0.2 g of lauryl mercaptan to emulsify the emulsion 5).

≪ Preparation of Emulsion of Acrylic Copolymer (4)

340 g of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel, and the temperature was raised to 60 DEG C while blowing nitrogen therein. 5.0 g of an aqueous solution of ammonium persulfate (active ingredient: 3%) and 5.0 g of an aqueous sodium hydrogen sulfite solution (active ingredient: 3%) were added to the emulsion (5) . Subsequently, 629.5 g of the remaining emulsion (2) and 40 g of ammonium persulfate aqueous solution (active ingredient: 1.25%) were dropwise added and polymerized for 8 hours while maintaining the reaction vessel at 60 ° C using respective funnels. After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 캜, and the contents were cooled. Subsequently, ammonia water (active ingredient 10%) was prepared so as to have a pH of 7.5. This was filtered through a 200 mesh wire netting to obtain 1013.5 g of an emulsion of the acrylic copolymer (5). The emulsion of the obtained acrylic copolymer (5) had a solid concentration of 50% and an average particle diameter of 340 nm.

[Preparation of aqueous dispersion type acrylic pressure-sensitive adhesive composition]

(Production Example 1)

1000 g of the emulsion of the acrylic copolymer (1) [anhydrous; 500 g] as a leveling agent, Surfynol PSA-336 (manufactured by Air Products Japan Co., Ltd.; 2.5 g of the active ingredient], 10 g of Surfanol DF-110D (manufactured by Air Products Japan KK; 2.5 g of active ingredient 100%], Superester NS-100H (manufactured by Arakawa Chemical Industries, Ltd., trade name; 125 g as a solid content and 0.15 g (0.03 mass part) of an epoxy compound Tetral C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent were added, and the mixture was filtered through a 200 mesh wire netting to obtain an acrylic type pressure- To obtain a composition (1).

(Production Example 2)

Acrylic pressure-sensitive adhesive composition (2) was prepared in the same manner as in Production Example 1 except that 0.1 g (0.03 mass part) of the crosslinking agent in Production Example 1 was used in an amount of 0.2 g (0.04 mass part).

(Production Example 3)

Acrylic pressure-sensitive adhesive composition (3) was prepared in the same manner as in Preparation Example 1 except that the amount of the crosslinking agent in Production Example 1 was changed to 0.15 g (0.03 mass part) in an amount of 0.25 g (0.05 mass part).

(Production Example 4)

Superester E-865NT (manufactured by Arakawa Chemical Industries, Ltd.) was used in place of 125 g of the solid content of the tackifier resin Superester NS-100H used in Production Example 1; Glass transition temperature 100 占 폚] as solid content, 62.5 g of Super Ester E-200NT (manufactured by Arakawa Chemical Industries, Ltd.; Except that 62.5 g of a solid content of 62.5 g and a content of a cross-linking agent of 0.15 g (0.03 mass part) were used in an amount of 0.35 g (0.07 mass part) in the same manner as in Production Example 1. The acrylic pressure- 4).

(Production Example 5)

1000 g of the emulsion of the acrylic copolymer (1) used in Production Example 3 [anhydrous; Acrylic pressure-sensitive adhesive composition (5) was prepared in the same manner as in Production Example 3, except that the acrylic copolymer (2) was used instead of the acrylic copolymer (2).

(Production Example 6)

Acrylic pressure-sensitive adhesive composition (6) was prepared in the same manner as in Production Example 5, except that 0.4 g (0.08 parts by mass) of the crosslinking agent in Production Example 5 was added in an amount of 0.25 g (0.05 part by mass).

(Production Example 7)

1000 g of the emulsion of the acrylic copolymer (2) used in Production Example 6 [anhydrous; Acrylic pressure-sensitive adhesive composition (7) was prepared in the same manner as in Production Example 6, except that the acrylic copolymer (3) was used instead of the acrylic copolymer (3).

(Preparation Example 8)

Acrylic pressure-sensitive adhesive composition (8) was prepared in the same manner as in Preparation Example 7 except that 0.5 g (0.1 part by mass) of the crosslinking agent in Production Example 7 was added in an amount of 0.4 g (0.08 part by mass).

(Preparation Example 9)

Superester E-200NT (manufactured by Arakawa Chemical Industries, Ltd.) was used in place of 125 g of the solid content of the tackifier resin Superester NS-100H used in Production Example 1; Acrylic pressure-sensitive adhesive composition (9) was obtained in the same manner as in Production Example 1, except that 125 g of a solid component and a compounding amount of a crosslinking agent of 0.15 g (0.03 mass part) were used in an amount of 0.35 g (0.07 mass part) ).

(Preparation Example 10)

Superester E-865NT (manufactured by Arakawa Chemical Industries, Ltd.) was used in place of 125 g of the solid content of the tackifier resin Superester NS-100H used in Production Example 1; (10) was prepared in the same manner as in Preparation Example 1, except that 125 g of a solid content of 125 g and a content of a crosslinking agent of 0.15 g (0.03 mass part) were used in place of the acrylic pressure-sensitive adhesive composition ).

(Preparation Example 11)

The same procedure as in Production Example 1 was carried out except that 50 g was used instead of 125 g of the solid content of the tackifier resin Superester NS-100H used in Production Example 1, and 0.35 g (0.07 mass part) of the compounding amount of the crosslinking agent was changed to 0.35 g , Thereby preparing a water dispersible acrylic pressure-sensitive adhesive composition (11).

(Production Example 12)

Except that 200 g was used instead of 125 g of the solid content of the tackifier resin Superester NS-100H used in Production Example 1 and 0.1 g (0.03 mass part) of the crosslinking agent was used in an amount of 0.5 g (0.1 mass part) To prepare a water dispersible acrylic pressure-sensitive adhesive composition (12).

(Preparation Example 13)

1000 g of an emulsion of the acrylic copolymer (1) used in Production Example 4 [anhydrous; Acrylic pressure-sensitive adhesive composition (13) was prepared in the same manner as in Production Example 4, except that the acrylic copolymer (4) was used instead of the acrylic copolymer (4).

(Preparation Example 14)

1000 g of an emulsion of the acrylic copolymer (1) used in Production Example 4 [anhydrous; Acrylic pressure-sensitive adhesive composition (14) was prepared in the same manner as in Production Example 4, except that the acrylic copolymer (5) was used instead of the acrylic copolymer (5).

(Comparative Production Example 1)

Acrylic pressure-sensitive adhesive composition (H1) was prepared in the same manner as in Production Example 4 except that 0.15 g (0.03 parts by mass) of the crosslinking agent in Production Example 4 was added in an amount of 0.35 g (0.07 parts by mass).

(Comparative Production Example 2)

(H2) was prepared in the same manner as in Production Example 1, except that the amount of the crosslinking agent in Production Example 1 was changed to 0.1 g (0.03 mass part) of the crosslinking agent in an amount of 0.4 g (0.08 mass part).

(Comparative Production Example 3)

Acrylic pressure-sensitive adhesive composition (H3) was prepared in the same manner as in Production Example 5 except that the amount of the crosslinking agent in Production Example 5 was changed to 0.15 g (0.03 parts by mass) in an amount of 0.25 g (0.05 part by mass).

(Comparative Production Example 4)

Acrylic pressure-sensitive adhesive composition (H4) was prepared in the same manner as in Production Example 5 except that 0.2 g (0.05 mass part) of the crosslinking agent in Production Example 5 was used in an amount of 0.2 g (0.05 mass part).

(Comparative Production Example 5)

Acrylic pressure-sensitive adhesive composition (H5) was prepared in the same manner as in Production Example 5 except that 0.5 g (0.1 part by mass) of the crosslinking agent in Production Example 5 was added in an amount of 0.25 g (0.05 part by mass).

(Comparative Production Example 6)

Acrylic pressure-sensitive adhesive composition (H6) was prepared in the same manner as in Preparation Example 7 except that 0.6 g (0.03 part by mass) of the crosslinking agent in Production Example 7 was added in an amount of 0.4 g (0.08 part by mass).

[Production of adhesive tape]

(Example 1)

The aqueous dispersion type acrylic pressure-sensitive adhesive composition (1) obtained in Preparation Example 1 was coated on a polyester film having a thickness of 75 占 퐉 which had been subjected to release treatment so as to have a thickness after drying of 20 占 퐉 and dried at 85 占 폚 for 2 minutes to obtain a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer thus obtained was transferred to both surfaces of the ink coating film (A), laminated at a pressure of 4 kgf / cm with a heat roll at 80 캜, and cured at 40 캜 for 2 days to obtain a double-faced pressure sensitive adhesive tape of Example 1.

(Examples 2 to 14)

Sensitive adhesive tapes of Examples 2 to 14 were obtained in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive compositions (2) to (14) obtained in Production Examples 2 to 14 were used.

(Comparative Examples 1 to 6)

Sensitive adhesive tapes of Comparative Examples 1 to 6 were obtained in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive compositions (H1) to (H6) obtained in Comparative Production Examples 1 to 6 were used.

The pressure-sensitive adhesive compositions and pressure-sensitive adhesive tapes obtained in Examples 1 to 8 and Comparative Examples 1 to 6 were subjected to the following evaluations. The obtained results are shown in the table.

(Measurement of Glass Transition Temperature of Acrylic Copolymer)

Using the emulsion of the acrylic copolymer, a sheet was prepared in accordance with the production conditions of the adhesive tape, and the sheet was overlapped to a thickness of 5 mm to prepare a test piece. Using a viscoelasticity tester (product name: Ares 2KFRTN1, manufactured by Rheometrics Co.), a specimen was sandwiched between parallel discs which were the measuring part of the tester, and the storage elastic modulus at -50 ° C to 150 ° C at a frequency of 1 Hz and a temperature- (G ') and the loss elastic modulus (G ") were measured, and tan delta was calculated based on the following equation to obtain a glass transition temperature.

(Measurement of glass transition temperature of tackifier resin)

The tackifier resin was dried in a vacuum dryer at 60 DEG C for 2 days or more using a vacuum dryer to obtain a test sample having a dry weight of 10 mg. The test sample was subjected to continuous DSC curve twice at a heating rate of 2 캜 / min in a temperature range of -50 캜 to 200 캜 using a DSC measuring apparatus (DSC822, manufactured by Mettler-Toledo) And the glass transition temperature was measured from the second measurement data.

(Measurement of glass transition temperature of pressure-sensitive adhesive layer)

The pressure-sensitive adhesive layer prepared according to the production conditions of the pressure-sensitive adhesive tape was laminated up to a thickness of 5 mm to prepare a test piece. Using a viscoelasticity tester (product name: Ares 2KFRTN1, manufactured by Rheometrics Co.), a specimen was sandwiched between parallel discs which were the measuring part of the tester, and the storage elastic modulus at -50 ° C to 150 ° C at a frequency of 1 Hz and a temperature- (G ') and the loss elastic modulus (G ") were measured, and tan delta was calculated based on the following equation to obtain a glass transition temperature.

tan? = G? / G?

(Measurement of gel fraction of pressure-sensitive adhesive layer)

The test piece was prepared on a polyester film (peeled) so that the thickness after drying was 25 占 퐉 according to the production conditions of the adhesive tape. The test piece was cut into a size of 20 mm x 100 mm, and the polyester film was peeled off and the weight a before the toluene extraction was measured. Next, the same test piece was immersed in toluene for 24 hours, the gel was taken out, dried at 100 ° C for 2 hours, and the weight b after toluene extraction was measured. The gel fraction was calculated from the following equation.

Gel fraction (%) = (b / a) x 100

(Bending / deformation test of optical film)

The pressure-sensitive adhesive tape prepared above was attached to a glass plate with an adhesive tape (outer shape: 32 mm x 42 mm, width: 2 mm) punched in a frame shape as shown in Fig. 1 at 23 ° C, (Outer appearance: 30 mm x 40 mm, appearance change rate when standing for 5 minutes in a dryer at 85 DEG C / flow direction: +0.08%, width direction: -0.08%) of a thin optical film " BEFRP2RC " 1). The width at which the adhesive tape and the optical film were in contact with each other was 1 mm. The component was allowed to stand at 85 占 폚 for 72 hours and then left at 23 占 폚 for 1 hour to observe the appearance change at around 85 占 폚.

○: No deformation occurred in the optical film

?: Deformation occurred in the optical film

X: Large strain occurred in the optical film

(Resistance test)

As shown in Fig. 2, a 100 μm PET film (Emblem SA # 100 manufactured by Unica) and a 2 mm thick polycarbonate (PC) plate were stuck to a 3 mm wide tape. Thereafter, pressurization was performed under the condition of reciprocating one 2-kg roller, and the peel-off separation was observed after standing at 60 ° C and 90% RH for 72 hours. When lifting of 0.5 mm or more occurs, it is not suitable for a liquid crystal module fixing tape having a large thickness crossing.

O: Less than 0.5 mm in peeling off

X: More than 0.5 mm of peeling off

As apparent from Tables 1 to 3, the pressure-sensitive adhesive tape of Examples 1 to 14 of the present invention can appropriately suppress the bending and deformation of the optical film while using an aqueous pressure-sensitive adhesive in which VOC is reduced, . On the other hand, the pressure-sensitive adhesive tape of the comparative example was incapable of both suppressing bending and deformation of the optical film and resistance to bouncing.

10: Double-sided adhesive tape
11: Optical film
12: Glass
20: Adhesive tape
21: PC version
22: PET film
23: Double-sided tape

Claims (5)

As an adhesive tape used for fixing an optical film,
Sensitive adhesive composition comprising an acrylic copolymer having a glass transition temperature of -45 to -25 占 폚, a tackifier resin having a glass transition temperature of 30 占 폚 to 120 占 폚, and an acrylic pressure-sensitive adhesive composition containing a crosslinking agent, Sensitive adhesive composition according to claim 1, wherein the aqueous dispersion type acrylic pressure-sensitive adhesive composition is one in which emulsion particles of the acrylic copolymer are dispersed in an aqueous medium, and the acrylic copolymer is a 2-ethylhexyl Wherein the content of the tackifier resin relative to 100 parts by mass of the acrylic copolymer is 10 to 40 parts by mass,
Wherein the pressure-sensitive adhesive layer has a glass transition temperature of -5 DEG C or less and a gel fraction of 25 to 45%. The method according to claim 1, wherein the monomer component used in the production of the acrylic copolymer is (meth) acrylate having an alkyl group having 4 to 8 carbon atoms and containing 2-ethylhexyl acrylate, By mass to 98% by mass. delete The acrylic copolymer according to any one of claims 1 to 3, wherein the acrylic copolymer contains 40% by mass or more and 98% by mass or less of 2-ethylhexyl acrylate in the monomer component used for producing the acrylic copolymer, Wherein the pressure-sensitive adhesive tape is obtained by polymerizing a monomer component containing a nitrogen-containing monomer. The adhesive tape according to claim 1 or 2, wherein the optical film is a prism sheet.

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