JP5760571B2 - Colored adhesive tape for fixing polarizing film - Google Patents

Description

  The present invention relates to a polarizing film comprising a support having a colored layer made of colored ink and a pressure-sensitive adhesive layer made of a water-dispersed acrylic pressure-sensitive adhesive composition in which acrylic copolymer emulsion particles are dispersed in an aqueous medium. The present invention relates to a colored adhesive tape for fixing.

  Colored adhesive tapes are used in various industrial fields for purposes such as decoration, display, concealment, reflection, and shading. In particular, in the image display device of a small electronic terminal such as a mobile phone, which is highly demanded to be light, thin and small, when fixing an image display panel having a polarizing film on the surface or a backlight module, simultaneously with the performance of fixing these components. Colored adhesive tapes that have a light-shielding effect due to black coloring, an improvement in luminance due to white coloring, and a reduction in power consumption due to efficient use of light are used (see, for example, Patent Documents 1 and 2).

  The colored adhesive tape used for fixing the image display panel and backlight module of the image display device is a part that is pasted together at the time of defective manufacturing or repair, in addition to good adhesion that does not cause the panel to drop off during use. It is necessary to have good reworkability that can be peeled off when removing and repairing. In response to such a demand, a colored pressure-sensitive adhesive tape that realizes good adhesiveness and reworkability has been realized (see, for example, Patent Documents 3 to 4).

  On the other hand, in consideration of the environment, in recent years, it has been desired that the peripheral materials of these image display devices are shifted to materials having reduced VOC (volatile organic compounds). However, conversion from solvent-based adhesives to water-based adhesives is expected. However, when converting to a water-based pressure-sensitive adhesive, suitable anchoring to a support having a colored layer composed of a colored ink layer is not possible when suitable adhesion to an image display panel or a backlight module is not obtained. In some cases, it was difficult to obtain both the adhesiveness to the peripheral members of the image display device and the reworkability.

JP 2004-156015 A JP 2006-259495 A Japanese Patent Application Laid-Open No. 2005-200498 JP 2005-275053 A

  The problem to be solved by the present invention is that, even when a water-based pressure-sensitive adhesive with reduced VOC is used, it has suitable adhesion to a polarizing film and is suitable for a support having a colored ink layer. An object of the present invention is to provide a colored pressure-sensitive adhesive tape for fixing a polarizing film, which has a rework property that is more suitable for its ring property.

  In the present invention, a polarizing film fixing colored adhesive tape for fixing a polarizing film of an image display device, the adhesive layer on the colored layer surface of the support provided with a colored layer made of colored ink, The pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed from a water-dispersed acrylic pressure-sensitive adhesive composition in which acrylic copolymer emulsion particles are dispersed in an aqueous medium, and an acrylic that forms the acrylic copolymer emulsion particles. The system copolymer contains a (meth) acrylate having a C 4-8 alkyl group, a carboxyl group-containing monomer, and a nitrogen-containing vinyl monomer as monomer components, and has the C 4-8 alkyl group. Carbon number in the monomer component which contains 2-ethylhexyl acrylate as (meth) acrylate and forms the acrylic copolymer The content of (meth) acrylate having 8 to 8 alkyl groups is 50 to 98% by mass, the content of carboxyl group-containing monomers is 1 to 10% by mass, and the content of nitrogen-containing vinyl monomers having amide groups is 0.1. The said subject can be solved with the coloring adhesive tape for polarizing film fixation which is -5 mass%.

  According to the colored pressure-sensitive adhesive tape for fixing a polarizing film of the present invention, while using a water-based pressure-sensitive adhesive layer with reduced VOC, the anti-polarizing film adhesive property equal to or higher than that of a pressure-sensitive adhesive tape using a conventional solvent-based pressure-sensitive adhesive is used. Reworkability can be realized. For this reason, polarizing film fixing applications for image display devices that require excellent environmental compatibility and high functionality, especially for liquid crystal display devices and organic EL display devices used in small electronic terminals such as mobile phones. It can be suitably applied to film fixing applications.

  The colored adhesive tape for fixing a polarizing film of the present invention is a colored adhesive tape used for fixing a polarizing film of an image display device, and an adhesive layer is provided on a colored layer surface of a support having a colored layer made of colored ink. Colored adhesive tape. The pressure-sensitive adhesive layer provided on the colored layer surface is a pressure-sensitive adhesive layer formed from a water-dispersed acrylic pressure-sensitive adhesive composition in which acrylic copolymer emulsion particles are dispersed in an aqueous medium. The acrylic copolymer forming the combined emulsion particles contains a predetermined amount of (meth) acrylate having a C 4-8 alkyl group, a carboxyl group-containing monomer, and a nitrogen-containing vinyl monomer as monomer components, and has a carbon number. 2-ethylhexyl acrylate is contained as a (meth) acrylate having 4 to 8 alkyl groups.

[Support]
The support used in the present invention is a support having a colored layer, and the colored layer is a colored layer made of colored ink. As the colored ink used for the colored layer, a colored ink used for a colored tape such as a light-shielding tape or a light reflecting tape used for fixing the peripheral member of the image display device can be appropriately used. Especially, the halogen content of a colored layer is 0.3 mass% or less, Preferably it is 0.05 mass% or less, and the thing which does not contain a halogen substantially is especially preferable. Such a colored layer with a reduced halogen content uses colored ink that does not use halogen- or sulfur-containing resins such as vinyl chloride resin as the binder resin, and therefore, anchoring of the adhesive layer is particularly obtained. However, when the adhesive force of the pressure-sensitive adhesive layer is increased, it is difficult to obtain reworkability. However, in the present invention, suitable adhesion and reworkability can be realized even with a colored layer having a low halogen content. Here, the halogen content is a detection amount when analyzed by fluorescent X-rays. For example, as a fluorescent X-ray analyzer, “ZSX Primus”, “ZSX Primus II”, etc. manufactured by Rigaku are listed.

  As the colored layer, an ink layer made of a colored ink that 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 a 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, and a polyester urethane resin can be particularly preferably used from the viewpoint of the adhesiveness with the pressure-sensitive adhesive layer and the adhesiveness with the resin film on which the colored layer is laminated.

  When a polyester urethane resin is used as the binder resin, the polyester urethane resin preferably has a glass transition temperature of -30 ° C to 30 ° C, more preferably -20 ° C to 30 ° C, and -15 ° C. More preferably, it is -25 degreeC, and it is especially preferable that it is -10 degreeC-25 degreeC. When the tan δ peak temperature of the polyester urethane resin is within this range, the colored layer has suitable flexibility and hardness, so that it is particularly difficult to cause cracks in the colored layer during rework, and the ink flow at high temperatures. It is difficult for peeling to occur.

The glass transition temperature of the polyester urethane resin is defined as the glass transition temperature, which is the tan δ peak temperature of the dynamic viscoelastic spectrum at a frequency of 1 Hz measured as follows.
Polyester urethane resin is formed to a thickness of 50 μm with a bar coater. Next, from a specimen cut to a sample length of 20 mm (sample length of 20 mm, film thickness of 50 μm) using a viscoelasticity tester from −150 ° C. to 250 ° C. at a frequency of 1 Hz and a temperature increase time of 3 ° C./1 minute. The storage elastic modulus (G ′) and the loss elastic modulus (G ″) are measured. The loss tangent tan δ is calculated by the following calculation formula.
Loss tangent tan δ = G ″ / G ′
Examples of the viscoelasticity tester include DMS210, DMS220, and DMS6100 manufactured by Seiko Instruments Inc.

  The colored ink used in the colored layer contains a curing agent used in ordinary inks, but it is also preferable to contain an aliphatic or alicyclic isocyanate curing agent as the curing agent. By cross-linking polyester urethane having a glass transition temperature of −30 ° C. to 30 ° C. and aliphatic or alicyclic isocyanate forming a relatively flexible cross-linked structure, it is easy to control the elastic modulus, and the flow of ink at high temperature It becomes easy to suppress peeling of the ink interface and the pressure-sensitive adhesive interface caused by. Further, since it is easy to obtain a suitable elastic modulus, it is difficult to crack the ink layer at the time of reworking, and it is easy to obtain an effect that the occurrence of tape tearing hardly occurs.

  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, 1,8-diisocyanate-4. -Isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate are used. Further, trimers of these isocyanates can be preferably used, and among them, diisocyanate adducts, biurets, and nurates are preferable. Among these, hexamethylene diisocyanate or isophorone diisocyanate adduct, biuret, or nurate is preferable because the elastic modulus is easily controlled, and biuret or nurate is particularly preferable. A hardening | curing agent may be added independently and may add 2 or more types.

  As the colorant for coloring the color ink, known and conventional pigments and dyes not containing halogen can be used. When black, carbon black, when white, titanium oxide, calcium carbonate, barium sulfate, yellow In the case of yellow iron oxide, red is red pepper, cyan is blue, blue is aluminum powder, and pearl is mica titanium powder from the viewpoint of weather resistance, heat resistance, and dispersibility in ink resins. When the colored layer is a light shielding layer, those capable of forming a black ink layer are preferred, and carbon black is preferred because of its excellent light shielding properties. Moreover, when making a colored layer into a light reflection layer, what can form a white ink layer is preferable, and a titanium oxide can be used preferably.

  What is necessary is just to adjust suitably according to a use etc. as addition amount of a coloring agent, and 10 to 70% in the ink solid content containing a coloring agent is preferable. More preferably, it is 40 to 50%. If it is 10% or more, it preferably shows light shielding properties, and if it is 70% or less, the dispersion is good.

  When making a colored layer into a light shielding layer, it is preferable to contain an antiblocking agent in the colored ink to be used. Generation | occurrence | production of the pinhole by blocking can be suppressed by containing an antiblocking agent. Antiblocking agents such as silica, calcium carbonate, calcium phosphate, talc, etc., and organic compound antiblocking agents such as polyethylene wax (PE wax), fatty acid amide, fatty acid ester, higher fatty acid should be used. Is preferred. The particle-based anti-blocking agent prevents the blocking by forming irregularities on the surface of the ink layer and reducing the contact area between the ink surface and the back surface. On the other hand, the organic compound-based antiblocking agent prevents blocking by bleeding out on the surface of the ink layer. Therefore, it is preferable to use a particle-based anti-blocking agent and an organic compound-based anti-blocking agent in combination. In particular, silica that improves the adhesion to the pressure-sensitive adhesive is preferred as the particle-based antiblocking agent. Further, as the organic compound-based anti-blocking agent, PE wax that does not significantly reduce the adhesion with the pressure-sensitive adhesive is particularly preferable.

  The addition amount of the particle size blocking inhibitor is preferably 0.5 to 10% by mass with respect to the ink solid content. Among these, 1-5 mass% is more preferable. If it is 0.5 mass% or more, the effect of blocking prevention is exhibited suitably, and if it is 10 mass% or less, the ink film becomes brittle, and the tape is likely to be scratched during rework. On the other hand, the addition amount of the organic blocking inhibitor is preferably 0.5 to 10% by mass with respect to the ink solid content. Among these, 2-7 mass% is more preferable. If it is 0.5 mass% or more, the effect of blocking prevention is acquired suitably, and the adhesiveness and rework property with an adhesive will become favorable in it being 10 mass% or less. Moreover, you may contain other various additives as needed.

  What is necessary is just to adjust the thickness of a colored layer suitably according to a desired characteristic. For example, when the colored layer is a light-shielding layer, 1 to 10 μm is preferable and 3 to 7 μm is more preferable from the viewpoint of light-shielding properties and workability at the time of tape punching. In addition, it is preferable to make an ink layer into a low elasticity modulus from a viewpoint of rework property, so that the thickness of ink is thick.

  The colored layer may be a single layer, but two or more layers may be laminated depending on the desired concealability, light reflectivity, and light shielding property. In particular, when the colored layer is a light shielding layer, it is preferable to provide two or more colored layers in order to improve the light shielding property and prevent light leakage due to pinholes.

  The support used in the present invention is a support having the above colored layer, and a support having a colored layer laminated on at least one surface of a substrate such as a resin film can be preferably used. As a base material on which the colored layer is laminated, known and commonly used resin films used for pressure-sensitive adhesive sheets can be used, and examples thereof include cellophane, polyethylene, polypropylene, nylon, polystyrene, polyimide, and polyester. Among these, polyester is preferably used because it is excellent in strength and insulation. Polyethylene terephthalate can be preferably used because it has good adhesion to an ink layer using a polyurethane resin.

  As thickness of the resin film used as a support body, 6-100 micrometers is preferable. When the thickness is 6 μm or more, the film is hardly cracked at the time of peeling, and when it is 100 μm or less, peeling is hardly generated at the time of application to the adherend. More preferably, it is 12-50 micrometers.

  The resin film on which the colored layer is laminated may be colored white or black, and the resin film is a white resin film having light reflectivity when used for an image display unit such as an LCD module. In addition, the brightness of the image display device can be increased, which is preferable. Of these, white polyethylene terephthalate having insulating properties and light diffuse reflection properties is most preferred. Moreover, it is preferable in order to raise the contrast of an image display apparatus that a resin film is a black resin film which has light-shielding property. Among them, black polyethylene terephthalate is preferable because it can provide excellent light shielding properties.

  The support used in the present invention is not particularly limited as long as the colored layer is provided on at least one surface of the surface layer. Even if the colored film is provided only on one surface of the resin film, both surfaces of the resin film are used. The structure which has a colored layer may be selected suitably according to the intended purpose. As an example of a preferred embodiment, when the colored adhesive tape for fixing a polarizing film of the present invention is used as a light-shielding reflective tape, a light-reflective white resin film is used as the resin film, and black ink is used on the white resin film. A configuration provided with a light-shielding layer made of a black colored layer is preferable because it easily combines excellent light reflectivity and light-shielding properties.

  Commercially available light-reflective resin films include Reiko 37W01, 3M ESR, Toray E20 # 38, Mitsubishi Chemical Polyester Film W400 # 38, Teijin DuPont Teflex FW2 # 13, etc. However, it is preferable because the thickness is thin and the reflectivity is high.

  Lamination of the colored layer on the resin film can be performed by printing by a known and commonly used printing method. For example, letterpress printing, flexographic printing, dry offset printing, gravure printing, gravure offset printing, offset printing, screen printing, and the like can be employed. Among them, the gravure printing is suitable for the repeated coating. The film surface to be ink-coated is preferably subjected to a known and commonly used easy adhesion treatment. Of these, easy adhesion treatment selected from corona treatment, plasma treatment, and primer treatment is preferred.

When the colored tape shielding tape or shielding reflective tape of the present invention preferably has a light transmission amount of when irradiated with light of 10000 cd / ^{m 2} on the support is 1 cd / ^{m 2} or less, 0.1 cd / M ² or less is more preferable.

[Adhesive layer]
The pressure-sensitive adhesive layer used in the present invention is a pressure-sensitive adhesive layer formed by crosslinking a water-dispersed acrylic pressure-sensitive adhesive composition in which acrylic copolymer emulsion particles are dispersed in an aqueous medium. The acrylic copolymer forming the acrylic copolymer emulsion particles is a monomer component comprising a (meth) acrylate having a C 4-8 alkyl group, a carboxyl group-containing monomer, and a nitrogen-containing vinyl monomer. Quantitatively contained, 2-ethylhexyl acrylate is contained as the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms. In the present invention, the pressure-sensitive adhesive layer is used as a pressure-sensitive adhesive layer to be laminated with the surface of the colored layer of the support, so that it is suitable as a polarizing film even when the pressure-sensitive adhesive layer is an aqueous pressure-sensitive adhesive layer. In addition to achieving good adhesion, the anchoring between the support and the pressure-sensitive adhesive layer becomes good, and suitable reworkability can be realized.

  In the present invention, (meth) acrylate having an alkyl group having 4 to 8 carbon atoms is used as a monomer component of the acrylic copolymer, and 2 as a (meth) acrylate having an alkyl group having 4 to 8 carbon atoms. -Contains ethylhexyl acrylate. By using 2-ethylhexyl acrylate as a monomer component, it is possible to realize suitable adhesiveness with the colored layer, and therefore, suitable reworkability can be imparted to the resulting adhesive tape. In addition, by using 2-ethylhexyl acrylate, when a tackifying resin is used in the pressure-sensitive adhesive composition, compatibility with the tackifying resin is easily improved, and adhesion with a substrate or an adherend is facilitated. It becomes easy to improve the property.

  In addition, in combination with 2-ethylhexyl acrylate, by using a (meth) acrylate having an alkyl group having 4 to 8 carbon atoms other than 2-ethylhexyl acrylate, the strong adhesiveness is improved while maintaining reworkability. Can do. Examples of (meth) acrylates having an alkyl group having 4 to 8 carbon atoms other than 2-ethylhexyl acrylate include n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and isooctyl (meth) acrylate. (Meth) acrylates such as n-octyl (meth) acrylate can be used, among which acrylate monomers having an alkyl group having 4 to 8 carbon atoms are preferable, and n-butyl acrylate is particularly preferable.

  In the present invention, the 2-ethylhexyl acrylate and the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms can be expressed more suitably in the monomer component forming the acrylic copolymer. The content of the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms including ethylhexyl acrylate is preferably 50 to 98 mass% in the monomer component forming the acrylic copolymer, and is preferably 80 to 98 mass%. % Is particularly preferable. Further, among (meth) acrylates having an alkyl group having 4 to 8 carbon atoms, content of (meth) acrylate having 2-ethylhexyl acrylate and other alkyl groups having 4 to 8 carbon atoms other than 2-ethylhexyl acrylate Is preferably 9/1 to 2/8 in mass ratio represented by (2-ethylhexyl acrylate / other (meth) acrylate having an alkyl group having 4 to 8 carbon atoms), 75/25 It is particularly preferred that it is ˜25 / 75. By keeping the content of these monomer components in this range, it is easy to suppress the adhesion between the pressure-sensitive adhesive and the adherend over time while maintaining suitable co-adhesiveness, and the adhesive force is not likely to increase excessively. , Suitable reworkability can be maintained over time.

  In the present invention, (meth) acrylate monomers other than those described above may be used in combination as the (meth) acrylate monomer that forms the acrylic copolymer. Examples of other (meth) acrylate monomers include (meth) acrylate monomers such as methyl (meth) acrylate and ethyl (meth) acrylate, and one or more of these may be used in combination. . Especially, it is preferable to use together (meth) acrylate which has a C2-C2 alkyl group, such as methyl (meth) acrylate and ethyl (meth) acrylate, and it is preferable that it is 1-10 mass% as usage-amount. .

  In the present invention, a carboxyl group-containing monomer is used in order to increase the cohesive force within and between the acrylic copolymer emulsion particles. As the carboxyl group-containing monomer, one or more selected from carboxyl group-containing vinyl monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, phthalic acid, phthalic anhydride, and crotonic acid are used. it can. Among them, acrylic acid and methacrylic acid are easy to ensure cohesive force by interaction between carboxyl groups, and there are many means for increasing cohesive force with many reactive crosslinking agents, and can express interaction with nitrogen-containing vinyl monomer described later. And the like. Furthermore, in the present invention, acrylic acid tends to be oriented in the vicinity of the particle surface and methacrylic acid is oriented inside the particle by using acrylic acid having relatively high hydrophilicity and methacrylic acid that is more hydrophobic than acrylic acid. The acid groups can be arranged in a well-balanced manner on the surface and inside of the acrylic copolymer emulsion particles. The presence of acid groups in the vicinity of the particle surface can ensure cohesion between emulsion particles, and the presence of acid groups present in the particles can improve cohesion within emulsion particles. Thereby, the obtained pressure-sensitive adhesive layer can reduce a portion having a low cohesive force and can suitably suppress deterioration of reworkability with time. .

  The content of the carboxyl group-containing monomer is 0.5 to 10% by mass, preferably 0.5 to 5% by mass, more preferably 1.5 to 3.5% by mass in the monomer component forming the acrylic copolymer. %. By setting it within this range, the crosslinking reaction with the crosslinking agent easily proceeds well. Furthermore, when the pressure-sensitive adhesive layer is formed, a cohesive force suitable for the pressure-sensitive adhesive layer is ensured, and it is easy to achieve both reworkability and strong adhesiveness.

  When acrylic acid and methacrylic acid are used in combination as the carboxyl group-containing monomer, the combined ratio is preferably a methacrylic acid / acrylic acid molar equivalent ratio of 1 or more, more preferably 1.3 or more. Preferably, it is 2 or more. By setting the combined ratio within the above range, the amount of surface acid groups and the amount of internal acid groups in the acrylic copolymer emulsion particles can be suitably controlled, and it becomes easier to realize better reworkability.

  In the present invention, a nitrogen-containing vinyl monomer is further used as the monomer component of the acrylic copolymer. The nitrogen-containing vinyl monomer is presumed to produce an effect of drawing a carboxyl group that is easily oriented on the particle surface into the particle by interacting with an acid group, particularly a carboxyl group, in the acrylic copolymer emulsion particles. The content of the nitrogen-containing vinyl monomer is 0.1 to 4.5% by mass, preferably 0.5 to 4% by mass, more preferably 0.5 to 3.5% by mass. The effects of the invention can be suitably expressed. On the other hand, when the content is increased, the reactivity with the crosslinking agent described later tends to decrease, but by setting the content to the upper limit or less, necessary reactivity can be ensured. When the content is within this range, the acid group distribution in the acrylic copolymer emulsion particles can be easily converged to a suitable distribution range.

  As the nitrogen-containing vinyl monomer, a nitrogen-containing monomer having an amide group can be preferably used. Compared with amine-based nitrogen-containing monomer groups, nitrogen-containing monomers having an amide group do not have too strong interaction with acid groups, and can suitably maintain cohesive force in emulsion particles and interaction between particles, Since cohesive force as a pressure-sensitive adhesive is easily obtained, suitable adhesiveness and reworkability are easily obtained. As the nitrogen-containing monomer having an amide group, for example, one or more selected from N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylonitrile, acrylamide, and N, N-dimethylacrylamide can be used.

  The ratio of the nitrogen-containing vinyl monomer and the vinyl monomer having a carboxyl group in the acrylic copolymer is not particularly limited, but the number of moles of the nitrogen-containing vinyl monomer in the monomer component constituting the acrylic copolymer. Is X, and the molar ratio X / Y is preferably from 1/1 to 1/20, more preferably from 1/1 to 1/5, where Y is the number of moles of the vinyl monomer having a carboxyl group. 1-1 / 3 is more preferable. If it is in the said range, reaction with the vinyl monomer which has a carboxyl group, and the crosslinking agent mentioned later will advance easily. Furthermore, it becomes easy to converge the distribution of carboxyl groups in the acrylic copolymer emulsion to a range described later.

  In the acrylic copolymer used in the present invention, monomers other than those described above can be used as necessary. Examples of such monomers include a hydroxyl group-containing monomer, (meth) acrylic acid 2-hydroxy Alcoholic hydroxyl group-containing monomers such as ethyl, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like can be used as appropriate. As keto group or aldehyde group-containing monomer, diacetone acrylamide, diacetone methacrylamide, acrolein, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, 2-hydroxypropyl Examples include acrylate acetoacetate and butanediol acrylate acetate. As the silane monomer, 3-methacryloxypropylmethyldimethoxysilane [for example, KBM-502 manufactured by Shin-Etsu Chemical Co., Ltd.], 3-methacryloxypropyltrimethoxysilane [for example, KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.], 3 -Methacryloxypropylmethyldiethoxysilane [for example, KBE-502 manufactured by Shin-Etsu Chemical Co., Ltd.], 3-methacryloxypropyltriethoxysilane [for example, KBE-503 manufactured by Shin-Etsu Chemical Co., Ltd.], 3-acryloxypropyltri And methoxysilane [for example, KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.]. Moreover, N methylol acrylamide etc. are mentioned as a methylol group containing monomer. Examples of the phosphoric acid group-containing monomer include Sipomer PAM-100, PAM-200, and PAM-300 manufactured by Rhodia Nikka Co., Ltd., and 20% by mass or less in the monomer component forming the acrylic copolymer. It can be used at a ratio of 1 type or 2 types or more.

  The weight average molecular weight of the acrylic copolymer used in the present invention is preferably 500 to 1,200,000, more preferably 60 to 1,000,000. By setting it as the said range, the softness | flexibility at the time of an adhesive impregnating a nonwoven fabric and cohesion force required for rework property can be reconciled in balance. The said weight average molecular weight is standard polystyrene conversion by a gel permeation chromatography (GPC). As measurement conditions, TSKgel GMHXL [manufactured by Tosoh] is used as the column, the column temperature is 40 ° C., 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 in the polymerization. Examples of the chain transfer agent include known chain transfer agents such as lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimethylcapto-1-propanol. Can be used.

(Type of tackifying resin)
In the water-dispersed acrylic pressure-sensitive adhesive composition used in the present invention, it is preferable to use a tackifying resin in order to adjust the strong adhesiveness of the resulting pressure-sensitive adhesive layer. 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 tackifying resin include rosin, polymerized rosin, polymerized rosin ester, rosin phenol, stabilized rosin ester, disproportionated rosin ester, terpene, terpene phenol, petroleum resin, etc. Can be illustrated.

  Among these, a polymerized rosin ester-based tackifier resin and a rosin phenol-based tackifier resin are preferable, and it is particularly preferable to blend these in combination. Specifically, polymerized rosin ester-based tackifier resins are Superester E-650 [Arakawa Chemical Industries, Ltd.], Superester E-788 [Arakawa Chemical Industries, Ltd.], Superester E-786. 60 [Arakawa Chemical Industries, Ltd.], Super Ester E-865 [Arakawa Chemical Industries, Ltd.], Super Ester E-865NT [Arakawa Chemical Industries, Ltd.], Harrier Star SK-508 [Harima Chemicals ( Co., Ltd.] Harrier Star SK-508H [Harima Kasei Co., Ltd.], Harrier Star SK-816E [Harima Kasei Co., Ltd.], Harrier Star SK-822E [Harima Kasei Co., Ltd.], Harrier Star SK- 323NS [manufactured by Harima Chemicals Co., Ltd.] and the like, and rosin phenolic tackifying resins are Tamanoru E-100 [manufactured by Arakawa Chemical Industries, Ltd.], Tamanoru E 200 [(manufactured by Arakawa Chemical Industry Ltd.), Tamanol E-200NT Arakawa Chemical Industries, Ltd.], and the like.

  When these are used in combination, the ratio of the polymerized rosin ester-based tackifier resin (A) to the rosin phenol-based tackifier resin (B) is 5 / in a mass ratio represented by (A) / (B). It is preferably 1 to 1/5, more preferably 3/1 to 1/3, and still more preferably 1/1 to 1/3. If it is in the said range, rework property and strong adhesiveness can be improved with good balance.

  The softening point of the tackifying resin is preferably 120 to 180 ° C, more preferably 140 to 180 ° C. By adding a tackifying resin having a high softening point, strong adhesiveness is improved.

  In the blend ratio of the acrylic copolymer / tackifying resin, the acrylic copolymer / tackifying resin = 100/10 to 100/40 is preferable, and the acrylic copolymer / tackifying resin = 100 is more preferable. / 15 to 100/35. If it is in the said range, rework property and strong adhesiveness can be improved with good balance.

(Crosslinking agent)
In the water-dispersed acrylic pressure-sensitive adhesive composition used in the present invention, it is preferable to use a crosslinking agent for the purpose of improving the cohesive strength of the resulting pressure-sensitive adhesive layer. Examples of the crosslinking agent include known isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, polyvalent metal salt crosslinking agents, metal chelate crosslinking agents, keto-hydrazide crosslinking agents, oxazoline crosslinking agents, and carbodiimide crosslinking agents. A crosslinking agent, a silane crosslinking agent, a glycidyl (alkoxy) epoxysilane crosslinking agent, or the like can be used. Among them, a type of crosslinking agent that is added after the completion of polymerization and causes the crosslinking reaction to proceed is preferable. Examples thereof include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, a carbodiimide-based crosslinking agent, and a glycidyl (alkoxy) epoxysilane-based crosslinking agent. Specifically, in the isocyanate-based cross-linking agent, Bernock DNW-5000 [manufactured by DIC Corporation], Bernock DNW-5010 [manufactured by DIC Corporation], Bernock DNW-5100 [manufactured by DIC Corporation], Bernock DNW- 5500 [manufactured by DIC Corporation], Aquanate 100 [manufactured by Nippon Polyurethane Industry Co., Ltd.], Aquanate 105 [manufactured by Nippon Polyurethane Industry Co., Ltd.], Aquanate 110 [manufactured by Nippon Polyurethane Industry Co., Ltd.], Aquanate 120 [manufactured by Nippon Polyurethane Industry Co., Ltd.], Aquanate 130 [manufactured by Nippon Polyurethane Industry Co., Ltd.], Aquanate 200 [manufactured by Nippon Polyurethane Industry Co., Ltd.], Aquanate 210 [manufactured by Nippon Polyurethane Industry Co., Ltd.], LS2319 [manufactured by Sumika Bayer Urethane Co., Ltd.], LS2336 [Sumika Bayer Ure Tanhydr Co., Ltd.], Bayhydur 3100 [manufactured by Sumika Bayer Urethane Co., Ltd.] and the like, and epoxy crosslinking agents include Denacol EX-832 [Nagase Kasei Kogyo Co., Ltd.], Denacol EX-841 [Nagase Kasei] Kogyo Co., Ltd.], Tetrad C [Mitsubishi Gas Chemical Co., Ltd.], Tetrad X [Mitsubishi Gas Chemical Co., Ltd.], etc. Catalyst manufactured], Epocross WS-700 [manufactured by Nippon Shokubai Co., Ltd.], Epocross K-2010E [manufactured by Nippon Shokubai Co., Ltd.], Epocross K-2020E [manufactured by Nippon Shokubai Co., Ltd.], Epocross K-2030E [(stock) ) Manufactured by Nippon Shokubai Co., Ltd., and carbodiimide-based crosslinking agents include Carbodilite SV-02 [Nisshinbo Co., Ltd.], Carbodilite V-02 [Nisshinbo ( )], Carbodilite V-02-L2 [Nisshinbo Co., Ltd.], Carbodilite V-04 [Nisshinbo Co., Ltd.], Carbodilite E-01 [Nisshinbo Co., Ltd.], Carbodilite E-02 [Nisshinbo Co., Ltd.] )], Carbodilite E-03A [Nisshinbo Co., Ltd.], Carbodilite E-04 [Nisshinbo Co., Ltd.], and glycidyl (alkoxy) epoxysilane crosslinking agents, 2- (3,4-epoxycyclohexylethyltrimethoxy) Silane [KBM-303; Shin-Etsu Silicone Co., Ltd.], γ-glycidoxypropyltrimethoxysilane [KBM-403; Shin-Etsu Silicone Co., Ltd.], γ-glycidoxypropylmethyldiethoxysilane [KBE-402 Manufactured by Shin-Etsu Silicone Co., Ltd.], γ-glycidoxypropyltriethoxysilane [KBE-403; Manufactured by Co., Ltd.] and the like.

  Especially, it is preferable to use the crosslinking agent which reacts with the vinyl monomer which has an acid group, and the above-mentioned isocyanate type crosslinking agent, an epoxy compound, an oxazoline compound, a carbodiimide type crosslinking agent, a glycidyl (alkoxy) epoxysilane compound, etc. are preferable. The present invention is a technique characterized by ensuring the cohesive force of the acrylic copolymer over the whole by orienting an appropriate amount of acid groups both on the emulsion particle surface and inside the particle. By using a cross-linking agent that reacts with an acid group, an improvement in cohesion can be suitably achieved.

  The content of the cross-linking agent may be adjusted as appropriate, and the degree of cross-linking can be adjusted using the value of the gel fraction for measuring the insoluble content after the pressure-sensitive adhesive layer is immersed in toluene for 24 hours as an index of the degree of cross-linking. The gel fraction is preferably 80% by mass or less. More preferably in the range of 3 to 75% by mass, and still more preferably in the range of 15 to 50% by mass, reworkability and strong adhesiveness can be secured in a balanced manner.

(Additive)
In the water-dispersed acrylic pressure-sensitive adhesive composition used in the present invention, as an additive, a base (such as aqueous ammonia) for adjusting the pH within a range that does not impair the desired effect of the present invention, if necessary, Acids, plasticizers, softeners, antioxidants, fillers such as glass and plastic fibers, balloons, beads, and metal powders, colorants such as pigments and dyes, pH adjusters, film formation aids, leveling agents, Known agents such as thickeners, water repellents and antifoaming agents can be optionally added to the adhesive composition.

  As for the thickness of an adhesive layer, 5-50 micrometers is preferable, More preferably, it is 10-30 micrometers. If it is 5 μm or more, sufficient adhesiveness can be obtained, and if it is 50 μm or less, it can be suitably applied to a display device and the like that are becoming lighter and thinner.

[Colored adhesive tape for fixing polarizing film]
The colored pressure-sensitive adhesive tape for fixing a polarizing film of the present invention is a colored pressure-sensitive adhesive for fixing a polarizing film, in which a pressure-sensitive adhesive layer comprising the water-dispersed acrylic pressure-sensitive adhesive composition is provided on the surface of the colored layer of the support having the colored layer. It is a tape. With this configuration, even when a water-based pressure-sensitive adhesive layer is applied to the halogen-free colored layer, suitable adhesive force and reworkability can be realized.

  The colored adhesive tape for fixing the polarizing film of the present invention preferably has a halogen (chlorine / bromine / fluorine / iodine) content of 0.3% by mass or less, and 0.05% by mass or less, as the whole colored adhesive tape. Are more preferable, and those substantially not containing halogen are particularly preferable.

  Moreover, even if it is an adhesive tape which has an adhesive layer only on the single side | surface of a support body, a double-sided adhesive tape which has an adhesive layer on both surfaces may be sufficient, but when fixing two or more parts, it shall be a double-sided adhesive tape. Is preferred. The pressure-sensitive adhesive layer may be a single-layer pressure-sensitive adhesive layer or a plurality of pressure-sensitive adhesive layers laminated, or a plurality of pressure-sensitive adhesive tapes may be laminated.

  The pressure-sensitive adhesive layer can be formed on a resin film or a light shielding layer by a method generally used for application of a pressure-sensitive adhesive sheet. Specifically, for example, the composition for forming the pressure-sensitive adhesive layer can be directly applied to the support and dried, or it can be applied on the separator, dried, and then bonded to the support.

  The thickness of the colored adhesive tape for fixing a polarizing film of the present invention is preferably 20 to 100 μm, and more preferably 30 to 75 μm. Especially, it is especially preferable that it is 40-65 micrometers. Those having a thickness in this range can be suitably used for fixing components of an image display device, particularly for an image display device of a small electronic device.

  7-15 N / 20mm is preferable and, as for the 180 degree | times peel adhesive force with respect to the polarizing film of the colored adhesive tape for polarizing film fixation of this invention, 8-13 N / 20mm is more preferable. When the adhesive force is within the above range, the components can be suitably fixed when fixing the components of the image display device.

  As an embodiment of the colored pressure-sensitive adhesive tape for fixing a polarizing film of the present invention, any structure may be used as long as it has a pressure-sensitive adhesive layer attached to a polarizing film on the colored layer surface of a support having a colored layer. As a preferred specific example, a form having an adhesive layer on a colored layer of a support having a colored layer only on one side of the resin film, an adhesive layer on both sides of the support having a colored layer on one side of the resin film Examples include 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. In these forms, if the colored layer is a light shielding layer made of black ink, it can be used as a light shielding tape, and if it is a light reflection layer made of white ink, it can be used as a light reflecting tape. In addition, use a combination of the two, or use a light-reflective white film or a light-shielding black film as the resin film to be used, in combination with a light-shielding layer made of black ink or a light-reflective layer made of white ink. Also, a light-shielding reflective tape can be used.

[Usage]
Since the colored pressure-sensitive adhesive tape for fixing a polarizing film of the present invention has a suitable adhesive force to the polarizing film and good reworkability, it can be suitably used for fixing a polarizing film of various image display devices. In particular, a light-shielding tape, a light-reflecting tape, which is used for fixing a polarizing film of a thin image display device, which requires space-saving, component fixing and suitable light-shielding reflection performance, and requires reworkability at the time of failure or repair, It can be suitably used as a light-shielding reflective tape.

  As a suitable application example, a touch panel of an image display device having a touch panel in which a polarizing film is provided on the surface layer in the form of a colored double-sided adhesive tape punched into a frame shape, and an image display module such as an LCD module or an organic EL module Further, in the LCD module provided in the housing of the image display device, the LCD panel provided with the polarizing film on the surface layer and the backlight module can be exemplified.

  In an LCD module of an image display device using an LCD module, a suitable example of bonding an LCD panel having a polarizing film on the surface and a backlight module is application to a backlight LCD module. it can. As a general configuration of a backlight type LCD module, a reflective plate, a light guide plate, a diffusion sheet, a prism sheet (to increase brightness), etc., which are used as necessary, are laminated in a LCD module housing, and are guided. The structure which the surface layer of the backlight module by which the light source is arrange | positioned to the side and back of an optical board, and the LCD panel which has a polarizing film in the surface layer was bonded together by the colored double-sided adhesive tape can be illustrated. In addition, the backlight module is housed inside the LCD module housing, and the housing and the LCD panel having the polarizing film on the surface are bonded with a colored double-sided adhesive tape, or one side of the colored double-sided adhesive tape However, the structure which affixed over the surface layer of the said housing | casing and a backlight module, and the other surface was affixed with the LCD panel which has a polarizing film in a surface layer can also be illustrated suitably. As described above, in the image display device using the LCD module, the colored adhesive tape of the present invention preferably has a mode in which it is punched and sandwiched between the LCD panel having the polarizing film on the surface layer and the backlight module. It can be illustrated as an aspect.

  It can also be suitably applied to touch panel fixing in which a polarizing film is provided on at least one of the surface layers. The surface of the image display module such as an LCD module or an organic EL module housed in the housing of the image display device, and the polarizing film on the surface layer A configuration in which the polarizing film surface of the touch panel provided with is bonded with the colored double-sided adhesive tape of the present invention can be exemplified. Also in the said structure, the aspect pinched | interposed between the touchscreen and the image display module can be illustrated as a preferable aspect in the form by which the colored adhesive tape of this invention was pierce | punched like the frame shape.

  Since the image display device using the colored adhesive tape for fixing a polarizing film of the present invention has a low halogen content, the cause of malfunction and malfunction is reduced, and the reliability is high. Further, an image display device attached as a light-shielding reflective tape so that the light-shielding layer side faces the polarizing film side and the light-reflecting layer side faces the casing having the backlight or the image display module side can achieve excellent luminance.

  The colored adhesive tape for fixing the polarizing film of the present invention can suppress malfunction of peripheral devices and provides a highly reliable product. Therefore, various electronic devices, particularly electronic notebooks, mobile phones, smartphones (high function mobile phones) ), Can be suitably used for fixing a polarizing film of a display device of a miniaturized portable electronic device such as a PHS, a game device, an electronic book, a multi-function data terminal, and a mobile personal computer.

[Production example of polyester urethane]
(Polyester urethane resin (A))
A number average molecular weight obtained from an acid component of adipic acid / terephthalic acid = 50/50 and 3-methyl-1,5-pentanediol (hereinafter referred to as “four-flask” equipped with a stirrer, thermometer, reflux condenser and nitrogen gas introduction tube) 256.3 parts of 2,000 polyester diol (referred to as Mn) and 36.5 parts of isophorone diisocyanate were charged and reacted at 90 ° C. for 15 hours under a nitrogen stream. Next, 5.0 parts of isophoronediamine, 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 under a stirring frame at 40 ° C. for 3 hours to obtain a resin solid content. A polyester urethane resin (A) having a concentration of 30.0%, a Gardner viscosity UV (25 ° C.), an amine value of 0, and a mass average molecular weight (hereinafter referred to as Mw) of 67,000 was obtained. The obtained resin had a tan δ peak temperature of -8 ° C.

(Polyester urethane resin (B))
A four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube was charged with 223.1 parts of polyester diol of Mn = 1,000 obtained from adipic acid and neopentyl glycol and 64.4 parts of isophorone diisocyanate. The mixture was reacted at 90 ° C. for 15 hours under a nitrogen stream. Next, 11.3 parts of isophorone diamine, 1.2 parts of di-n-butylamine, 175 parts of toluene, 315 parts of ethyl acetate, and 210 parts of isopropylene alcohol were added and reacted at 40 ° C. for 3 hours under a stirring frame. A polyester urethane resin (B) having a partial concentration of 30.0%, a Gardner viscosity ST (25 ° C), an amine value of 0.5, and Mw of 100,000 was obtained. The peak temperature of tan δ of the obtained resin was −20 ° C.

[Black ink production example]
(Black ink production example 1)
4 parts of “Carbon Degussa Special 4A” manufactured by Degussa, 6 parts of “Carbon Special 250P” manufactured by Degussa, 40 parts of polyester urethane resin (A) (tan δ peak temperature = −8 ° C.), 23 parts of methyl ethyl ketone, toluene 13 parts, 6 parts of ethyl acetate, 3 parts of N-propyl acetate, and 3 parts of isopropyl alcohol were added, and the mixture was wet-dispersed with a sand mill for about 1 hour, and then a curing agent “KR90” (hexamethylene didiisocyanate of DIC) was added. A black ink (A) was prepared by adding 4 parts of biuret body) and 35 parts of DIC Corporation diluent “Direducer V No. 20”. In addition, resin represents solid content ratio.

(Black ink production example 2)
In place of the polyester urethane resin (A) of Production Example 1, polyester urethane resin (B) (polyester urethane resin, tan δ peak temperature = −20 ° C.) is used, and black ink (B )created.

[Production of support]
(Ink coat film (A))
A Terajin DuPont Films Co., Ltd. Teflex FW2 # 13 (thickness: 13 μm, tensile strength 23 N / 20 mm) is subjected to corona treatment so that the surface state becomes 50 dynes or more, and then the black ink (A) is dried to a thickness. Was twice gravure coated so that the thickness of the film became 4 μm. The drying was left at room temperature for 2 minutes. Thereafter, the film was cured at 40 ° C. for 2 days to obtain an ink coat film (A).

(Ink coat film (B))
An ink coat film (B) was obtained in the same manner as the ink coat film (A) except that the black ink (B) was used.

[Preparation method of acrylic copolymer emulsion]
(Preparation Example 1)
<Preparation of emulsion>
In a container, 75.0 g of ion-exchanged water and surfactant Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25%] 20.0 g and surfactant Latemul PD-104 [manufactured by Kao Corp .; effective Ingredient 20%] 37.5 g was added and dissolved uniformly. There, 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, 0.20 g of lauryl mercaptan were added and emulsified, Emulsion (1) 632.7 g was obtained.

<Preparation of emulsion of acrylic copolymer (1)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 340 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part [3.2 g] of the emulsion (1), 5.0 g ammonium persulfate aqueous solution [3% active ingredient], 5.0 g sodium hydrogen sulfite aqueous solution [3% active ingredient] were added, While maintaining, polymerization was carried out in 1 hour. Subsequently, the remaining emulsion (1) 629.5 g and ammonium persulfate aqueous solution 40 g [active ingredient 1.25%] were dropped and polymerized using a separate funnel over 8 hours while maintaining the reaction vessel at 60 ° C. . After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 ° C., and then the contents were cooled, and subsequently prepared with ammonia water (active ingredient 10%) so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain 1013.5 g of an acrylic copolymer (1) emulsion. Here, the emulsion of the obtained acrylic copolymer (1) had a solid content concentration of 50% and an average particle size of 338 nm.

(Preparation Example 2)
<Preparation of emulsion (2)>
In a container, 75.0 g of ion-exchanged water and surfactant Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25%] 20.0 g and surfactant Latemul PD-104 [manufactured by Kao Corp .; effective Ingredient 20%] 37.5 g was added and dissolved uniformly. There, 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, 0.2 g of lauryl mercaptan Was added and emulsified to obtain 632.7 g of an emulsified liquid (2).

<Preparation of emulsion of acrylic copolymer (2)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 340 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part [3.2 g] of emulsion (2), 5.0 g ammonium persulfate aqueous solution [3% active ingredient] and 5.0 g sodium hydrogen sulfite aqueous solution [3% active ingredient] were added, While maintaining, polymerization was carried out in 1 hour. Subsequently, 629.5 g of the remaining emulsion (2) and 40 g of an aqueous ammonium persulfate solution (active ingredient 1.25%) were dropped and polymerized using a separate funnel over 8 hours while maintaining the reaction vessel at 60 ° C. . After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 ° C., and then the contents were cooled, and subsequently prepared with ammonia water (active ingredient 10%) so that the pH was 7.5. This was filtered with a 200-mesh wire mesh to obtain 1013.5 g of an acrylic copolymer (2) emulsion. Here, the emulsion of the obtained acrylic copolymer (2) had a solid content concentration of 50% and an average particle size of 341 nm.

(Preparation Example 3)
<Preparation of emulsion (3)>
In a container, 75.0 g of ion-exchanged water and surfactant Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25%] 20.0 g and surfactant Latemul PD-104 [manufactured by Kao Corp .; effective Ingredient 20%] 37.5 g was added and dissolved uniformly. 457 g of n-butyl acrylate, 25.0 g of methyl methacrylate, 17.5 g of acrylic acid, 0.5 g of 2-hydroxyethyl acrylate, and 0.2 g of lauryl mercaptan were added and emulsified to obtain 632.7 g of the emulsion (3). Obtained.

<Manufacture of emulsion of acrylic copolymer (3)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 340 g of ion-exchanged water was added, and the temperature was raised to 65 ° C. while blowing nitrogen. While stirring, a part [3.2 g] of emulsion (3), 5.0 g of ammonium persulfate aqueous solution [3% active ingredient] and 5.0 g of sodium hydrogen sulfite aqueous solution [3% active ingredient] were added, While maintaining, polymerization was carried out in 1 hour. Subsequently, 629.5 g of the remaining emulsion (3) and 40 g of an aqueous ammonium persulfate solution (active ingredient 1.25%) were dropped and polymerized over 8 hours using a separate funnel while keeping the reaction vessel at 60 ° C. . After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 ° C., and then the contents were cooled, and subsequently prepared with ammonia water (active ingredient 10%) so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain 1013.5 g of an acrylic copolymer (3) emulsion. Here, the emulsion of the obtained acrylic copolymer (3) had a solid content concentration of 50% and an average particle size of 311 nm.

(Preparation Example 4)
<Preparation of emulsion (4)>
In a container, 75.0 g of ion-exchanged water and surfactant Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25%] 20.0 g and surfactant Latemul PD-104 [manufactured by Kao Corp .; effective Ingredient 20%] 37.5 g was added and dissolved uniformly. 457 g of n-butyl acrylate, 25.0 g of vinyl acetate, 17.5 g of acrylic acid, 0.5 g of 2-hydroxyethyl acrylate and 0.2 g of lauryl mercaptan were added and emulsified to obtain 632.7 g of the emulsion (4). Obtained.

<Manufacture of emulsion of acrylic copolymer (4)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 340 g of ion-exchanged water was added, and the temperature was raised to 65 ° C. while blowing nitrogen. While stirring, a part [3.2 g] of emulsion (4), 5.0 g ammonium persulfate aqueous solution [3% active ingredient], 5.0 g sodium hydrogen sulfite aqueous solution [3% active ingredient] were added, While maintaining, polymerization was carried out in 1 hour. Subsequently, the remaining emulsion (4) 629.5 g and ammonium persulfate aqueous solution 40 g [active ingredient 1.25%] were dropped and polymerized over 8 hours while keeping the reaction vessel at 60 ° C. using a separate funnel. . After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 ° C., and then the contents were cooled, and subsequently prepared with ammonia water (active ingredient 10%) so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain 1013.5 g of an acrylic copolymer (4) emulsion. Here, the emulsion of the obtained acrylic copolymer (4) had a solid content concentration of 50% and an average particle size of 308 nm.

(Preparation Example 5)
<Preparation of emulsion (5)>
In a container, 75.0 g of ion-exchanged water and surfactant Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25%] 20.0 g and surfactant Latemul PD-104 [manufactured by Kao Corp .; effective Ingredient 20%] 37.5 g was added and dissolved uniformly. 457 g of n-butyl acrylate, 25.0 g of methyl methacrylate, 17.5 g of acrylic acid, 0.5 g of 2-hydroxyethyl acrylate and 0.2 g of lauryl mercaptan were added and emulsified to obtain 632.7 g of the emulsion (5). Obtained.

<Manufacture of emulsion of acrylic copolymer (5)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 340 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part [3.2 g] of the emulsion (5), 5.0 g ammonium persulfate aqueous solution [3% active ingredient], 5.0 g sodium hydrogen sulfite aqueous solution [3% active ingredient] were added, While maintaining, polymerization was carried out in 1 hour. Subsequently, the remaining emulsion (5) 629.5 g and ammonium persulfate aqueous solution 40 g [active ingredient 1.25%] were dropped and polymerized over 8 hours using a separate funnel while keeping the reaction vessel at 60 ° C. . After completion of the dropwise addition, the reaction vessel was stirred for 2 hours while maintaining the temperature at 60 ° C., and then the contents were cooled, and subsequently prepared with ammonia water (active ingredient 10%) so that the pH was 7.5. This was filtered through a 200 mesh wire net to obtain 1013.5 g of an acrylic copolymer (5) emulsion. Here, the emulsion of the obtained acrylic copolymer (5) had a solid content concentration of 50% and an average particle size of 324 nm.

[Production of water-dispersed acrylic pressure-sensitive adhesive composition]
(Production Example 1)
To 1000 g [dry; 500 g] of the acrylic copolymer (1), Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as a leveling agent, defoaming Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as an agent, emulsion type polymerized rosin ester-based tackifier resin super ester E-865NT [Arakawa Chemical Industries ( Co., Ltd .; softening point 160 ° C.] solid content 62.5 g, emulsion type rosin phenol-based tackifying resin Tamanol E-200NT [Arakawa Chemical Industries, Ltd .; softening point 150 ° C.] solid content 62.5 g, cross-linked Epoxy compound tetrad C [Mitsubishi Gas Chemical Co., Ltd.] 0.05 g (0.01 mass) ) Was added, and filtered through a 200 mesh screen to obtain aqueous acrylic PSA composition (1).

(Production Example 2)
In Production Example 1, a water-dispersed acrylic is the same as Production Example 1 except that 0.15 g (0.03 parts by mass) of an epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] is added as a crosslinking agent. Type | system | group adhesive composition (2) was manufactured.

(Production Example 3)
In Production Example 1, a water-dispersed acrylic is the same as Production Example 1 except that 0.25 g (0.05 parts by mass) of an epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] is added as a crosslinking agent. Type | system | group adhesive composition (3) was manufactured.

(Production Example 4)
In Production Example 1, emulsion type polymerized rosin ester type tackifying resin superester E-865NT [manufactured by Arakawa Chemical Industries, Ltd .; softening point 160 ° C.] 50 g solid content, emulsion type rosin phenol type tackifying resin as tackifying resin TAMANOL E-200NT (manufactured by Arakawa Chemical Industry Co., Ltd .; softening point 150 ° C.) 50 g in solid content, epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] 0.15 g (0.03 parts by mass) as a crosslinking agent A water-dispersed acrylic pressure-sensitive adhesive composition (4) was produced in the same manner as in Production Example 2 except that it was used.

(Production Example 5)
To 1000 g [dry; 500 g] of the acrylic copolymer (2) emulsion, Surfynol PSA-336 [manufactured by Air Products Japan, Inc .; active ingredient 100%] 2.5 g as a leveling agent, defoaming Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as an agent, emulsion type polymerized rosin ester-based tackifier resin super ester E-865NT [Arakawa Chemical Industries ( Co., Ltd .; softening point 160 ° C.] solid content 62.5 g, emulsion type rosin phenol-based tackifying resin Tamanol E-200NT [Arakawa Chemical Industries, Ltd .; softening point 150 ° C.] solid content 62.5 g, cross-linked Epoxy compound tetrad C [Mitsubishi Gas Chemical Co., Ltd.] 0.05 g (0.01 mass) ) Was added, and filtered through a 200 mesh screen to obtain aqueous acrylic PSA composition (5).

(Production Example 6)
In Production Example 5, water-dispersed acrylic is the same as Production Example 5 except that 0.15 g (0.03 parts by mass) of an epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] is added as a crosslinking agent. Type | system | group adhesive composition (6) was manufactured.

(Production Example 7)
In Production Example 5, a water-dispersed acrylic is the same as Production Example 5 except that 0.25 g (0.05 parts by mass) of an epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] is added as a crosslinking agent. A pressure-sensitive adhesive composition (7) was produced.

(Production Example 8)
In Production Example 5, a water-dispersed acrylic resin was prepared in the same manner as in Production Example 5 except that 0.5 g (0.1 part by mass) of an epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] was added as a crosslinking agent. Type | system | group adhesive composition (8) was manufactured.

(Comparative Production Example 1)
To 1000 g [dry; 500 g] of the acrylic copolymer (3) emulsion, Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as a leveling agent, defoaming Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as an agent, emulsion type polymerized rosin ester-based tackifier resin super ester E-865NT [Arakawa Chemical Industries ( Co., Ltd .; softening point 160 ° C.] solid content 62.5 g, emulsion type rosin phenol-based tackifying resin Tamanol E-200NT [Arakawa Chemical Industries, Ltd .; softening point 150 ° C.] solid content 62.5 g, cross-linked 0.15 g (0.03 mass) of epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] as an agent ) Was added, and filtered through a 200 mesh screen to obtain aqueous acrylic PSA composition (H1).

(Comparative Production Example 2)
In Comparative Production Example 1, water dispersion was carried out in the same manner as in Comparative Production Example 1, except that 0.25 g (0.05 parts by mass) of the epoxy compound Tetrad C [Mitsubishi Gas Chemical Co., Ltd.] was added as a crosslinking agent. Type acrylic pressure-sensitive adhesive composition (H2) was produced.

(Comparative Production Example 3)
To 1000 g [dry; 500 g] of the acrylic copolymer (4) emulsion, Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as a leveling agent, antifoaming Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as an agent, emulsion type polymerized rosin ester-based tackifier resin super ester E-865NT [Arakawa Chemical Industries ( Co., Ltd .; softening point 160 ° C.] solid content 62.5 g, emulsion type rosin phenol-based tackifying resin Tamanol E-200NT [Arakawa Chemical Industries, Ltd .; softening point 150 ° C.] solid content 62.5 g, cross-linked Epoxy compound tetrad C [Mitsubishi Gas Chemical Co., Ltd.] 0.05 g (0.01 mass) ) Was added, and filtered through a 200 mesh screen to obtain aqueous acrylic PSA composition (H3).

(Comparative Production Example 4)
In Comparative Production Example 3, water dispersion was performed in the same manner as in Comparative Production Example 3, except that 0.15 g (0.03 parts by mass) of an epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] was added as a crosslinking agent. Type acrylic pressure-sensitive adhesive composition (H4) was produced.

(Comparative Production Example 5)
To 1000 g [dry; 500 g] of the above acrylic copolymer (5), Surfynol PSA-336 [manufactured by Air Products Japan Ltd .; active ingredient 100%] 2.5 g as a leveling agent, defoaming Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd .; active ingredient 100%] 2.5 g as an agent, emulsion type polymerized rosin ester-based tackifier resin super ester E-865NT [Arakawa Chemical Industries ( Co., Ltd .; softening point 160 ° C.] solid content 62.5 g, emulsion type rosin phenol-based tackifying resin Tamanol E-200NT [Arakawa Chemical Industries, Ltd .; softening point 150 ° C.] solid content 62.5 g, cross-linked 0.15 g (0.03 mass) of epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] as an agent ) Was added, and filtered through a 200 mesh screen to obtain aqueous acrylic PSA composition (H5).

(Comparative Production Example 6)
In Comparative Production Example 5, water dispersion was carried out in the same manner as Comparative Production Example 5 except that 0.25 g (0.05 parts by mass) of the epoxy compound Tetrad C [Mitsubishi Gas Chemical Co., Ltd.] was added as a crosslinking agent. Type acrylic pressure-sensitive adhesive composition was produced.

[Production of solvent-based acrylic pressure-sensitive adhesive composition]
(Reference Production Example 1)
In a reaction vessel equipped with a condenser, stirrer, thermometer, and dropping funnel, 93 parts of n-butyl acrylate, 3.4 parts of vinyl acetate, 3.5 parts of acrylic acid, 0.1 part of β-hydroxy-ethyl acrylate, polymerization As an initiator, 0.2 part of 2,2′-azobisisobutylnitrile is dissolved in 100 parts of ethyl acetate, substituted with nitrogen, polymerized at 80 ° C. for 8 hours, and an acrylic copolymer having a mass average molecular weight of 800,000 ( S1) was obtained. 100 parts of the acrylic copolymer (S1), 10 parts of “Superester A100” manufactured by Arakawa Chemical Co., Ltd., and 10 parts by weight of “Pencel D135” manufactured by Arakawa Chemical Industries are diluted with toluene to a solid content of 40%. A solvent-based acrylic pressure-sensitive adhesive composition (S1) was obtained.

[Production of adhesive tape]
Example 1
The water-dispersed acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was coated on a 75 μm-thick polyester film subjected to a release treatment so that the thickness after drying was 20 μm, and 85 ° C. And dried for 2 minutes to obtain an adhesive layer. The obtained pressure-sensitive adhesive layer was transferred to both sides of the ink coat film (A), laminated with a hot roll at 80 ° C. at a pressure of 4 kgf / cm, and further cured at 40 ° C. for 2 days. Obtained.

(Examples 2 to 8)
Double-sided pressure-sensitive adhesive tapes of Examples 2 to 8 were obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive compositions (2) to (8) obtained in Production Examples 2 to 8 were used. .

Example 9
The water-dispersed acrylic pressure-sensitive adhesive composition (2) obtained in Production Example 2 was applied on a 75 μm-thick polyester film subjected to release treatment so that the thickness after drying was 20 μm, and 85 ° C. And dried for 2 minutes to obtain an adhesive layer. The obtained pressure-sensitive adhesive layer was transferred to both sides of the ink coat film (B), laminated with a heat roll of 80 ° C. at a pressure of 4 kgf / cm, and further cured at 40 ° C. for 2 days. A double-sided adhesive tape was obtained.

(Example 10)
A double-sided pressure-sensitive adhesive tape of Example 10 was obtained in the same manner as in Example 9 except that the water-dispersed acrylic pressure-sensitive adhesive composition (7) obtained in Production Example 7 was used.

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

(Reference Example 1)
After 1.2 parts of “Coronate L-45” (isocyanate-based cross-linking agent) manufactured by Nippon Polyurethane Industry Co., Ltd. was blended in the solvent-based acrylic pressure-sensitive adhesive composition (S1) obtained in Reference Production Example 1, and sufficiently stirred Then, it was coated on a 75 μm-thick polyester film subjected to a release treatment so that the thickness after drying was 20 μm, and dried at 85 ° C. for 2 minutes to obtain an adhesive layer. This was transferred to both sides of the ink coat film (b), laminated with a heat roll at 80 ° C. at a pressure of 4 kgf / cm, and further cured at 40 ° C. for 2 days to obtain a double-sided pressure-sensitive adhesive tape of Reference Example 1. .

  Table 1 shows the monomer composition of the acrylic copolymer used in each composition obtained above. Moreover, about the adhesive layer and double-sided adhesive tape obtained by the said ink coat film, the Example, the comparative example, and the reference example, the following items were evaluated and the obtained result was shown to Tables 2-5.

[Measurement of elastic modulus, elongation, breaking strength, breaking elongation]
The black ink used for the ink coat film is processed into an ink coating with a width of 10 mm and a length of 150 mm, and under the conditions of an environmental temperature of 23 ° C. and a humidity of 50%, Tensilon Universal Tensile Tester (Orientec, RTA100) Was used to measure the elastic modulus, tensile strength, breaking strength, and breaking elongation when pulled at 300 mm / min when the chuck spacing was 100 mm.

[Adhesive strength]
The adhesive strength was determined by the following procedure in accordance with the JIS-Z0237 (2000) 180-degree peeling adhesive strength test method.
Stainless steel (SUS) plate and polarizing plate (iodine-type polarizing film: LCD panel with high luminance SR grade manufactured by Sumitomo Chemical Co., Ltd.) provided with a polarizing film on the surface layer, 20 mm wide backed with a polyester film 25 μm The pressure-sensitive adhesive tapes of Examples and Comparative Examples were subjected to one-way reciprocating pressure application with a 2 kg roller under the conditions of an environmental temperature of 23 ° C. and a humidity of 50%, and allowed to stand for 1 hour. Was pulled at a speed of 300 mm / min under the same temperature and humidity conditions, and peeled 180 degrees to measure the adhesive force.
In addition, the thing with the adhesive force with respect to glass of 8 N / 20mm or more was judged to be favorable.

[Reworkability]
The adhesive tapes of Examples and Comparative Examples with a white surface lined on a stainless steel plate with a polyester film of 25 μm and a comparative example were pressure-applied once with a 2 kg roller under the conditions of an environmental temperature of 23 ° C. and a humidity of 50% RH. Leave in an environmental tester at 60 ° C. for 24 hours. Then, after leaving at 23 ° C. for 1 hour, it was peeled off at a speed of 300 mm / min in an oblique direction of 135 °, and it was evaluated whether or not the adhesive could be peeled off without leaving any adhesive.
(Double-circle): It was able to peel without any adhesive residue.
○: A slight adhesive residue was generated, but it was peelable without any practical problem.
X: Adhesive residue is generated.

[Light shielding]
The light box “Flat Illuminator HF-SL-A48LCG” manufactured by Dentsu Sangyo Co., Ltd. is adjusted to 10000 cd / m ² , and a light-shielding adhesive tape is placed on the light box. ) Measure with an eye system luminance meter “eye scale 3”.

  As is clear from Tables 3 to 5, the colored adhesive tapes for fixing the polarizing films of Examples 1 to 10 of the present invention use a water-based adhesive with reduced VOC, and have suitable adhesiveness to the polarizing film. And having a suitable rework property due to a suitable anchoring property with respect to a support having a colored ink layer. On the other hand, the pressure-sensitive adhesive tape of the comparative example was inferior in adhesion to glass and reworkability.

Claims (9)

A colored pressure-sensitive adhesive tape for fixing a polarizing film for fixing a polarizing film of an image display device, having a pressure-sensitive adhesive layer on a colored layer surface of a support provided with a colored layer made of colored ink, the pressure-sensitive adhesive layer, A pressure-sensitive adhesive layer comprising a water-dispersed acrylic pressure-sensitive adhesive composition in which acrylic copolymer emulsion particles are dispersed in an aqueous medium, and the water-dispersed acrylic pressure-sensitive adhesive composition contains an epoxy compound as a crosslinking agent Is,
The acrylic copolymer forming the acrylic copolymer emulsion particles contains (meth) acrylate having a C 4-8 alkyl group, a carboxyl group-containing monomer, and a nitrogen-containing vinyl monomer as monomer components. ,
Containing 2-ethylhexyl acrylate as the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms,
The content of the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms in the monomer component forming the acrylic copolymer is 50 to 98% by mass, and the content of the carboxyl group-containing monomer is 1 to 10% by mass. A colored adhesive tape for fixing a polarizing film, wherein the content of the nitrogen-containing vinyl monomer is 0.1 to 5% by mass. The colored adhesive tape for fixing a polarizing film according to claim 1, wherein the colored layer is made of a colored ink having a polyurethane-based resin as a binder resin. The colored adhesive tape for fixing a polarizing film according to claim 2, wherein the polyurethane resin is a polyester polyurethane resin having a glass transition temperature of -30 to 30 ° C. The colored adhesive tape for fixing a polarizing film according to claim 1, wherein the colored ink contains an antiblocking agent. Content of the said 2-ethylhexyl acrylate is 20-90 mass% in the (meth) acrylate which has the said C4-C8 alkyl group, For polarizing film fixation in any one of Claims 1-4 Colored adhesive tape. Examples of the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms include n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isooctyl (meth) acrylate and n-octyl (meta The colored adhesive tape for fixing a polarizing film according to any one of claims 1 to 5, which contains at least one selected from acrylate). The polarizing film according to claim 1, wherein the nitrogen-containing vinyl monomer is at least one selected from N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylonitrile, acrylamide, and N, N-dimethylacrylamide. Colored adhesive tape for fixing. As the carboxyl group-containing monomer, acrylic acid and methacrylic acid are contained, and the content ratio of acrylic acid and methacrylic acid is 1.3 or more in terms of molar equivalent ratio represented by (methacrylic acid / acrylic acid). The colored adhesive tape for polarizing film fixation in any one of Claims 1-7. The colored adhesive tape for fixing a polarizing film according to any one of claims 1 to 8 , wherein the colored layer made of colored ink is a light-shielding layer made of black colored ink.