TWI669571B - Photocurable adhesive composition, polarizing plate and manufacturing method thereof, optical member and liquid crystal display device - Google Patents

Abstract

The present invention provides a low-viscosity photocurable adhesive, and a polarizing plate obtained by bonding a protective film to a polarizer using the adhesive. The light-curable adhesive is manufactured by using a resin film with low moisture permeability as a material. In the case of a polarizing plate for a protective film, it has excellent hardening properties even in high humidity in the coating environment. The adhesion force after a certain period of time is good against various forces, and it does not cause problems after the endurance test. good.

A photocurable adhesive composition is an adhesive composition for a polarizer containing a polyvinyl alcohol-based resin film, and a protective film comprising a transparent resin film selected from a specific four types, which is contained in a specific ratio (A) poly (meth) acrylate of a polyhydric alcohol having 2 to 15 carbon atoms, (B) polyglycidyl ether of a polyhydric alcohol having 2 to 10 carbon atoms, and (C) having 1 molecule Two or more oxocyclobutane compounds having a molecular weight of 500 or less, (D) a polymer having an epoxy group, and (E) a photocationic polymerization initiator.

Description

Photocurable adhesive composition, polarizing plate and manufacturing method thereof, optical member and liquid crystal display device

The present invention relates to a photocurable adhesive composition for bonding a polarizer and a protective film in a polarizer, a polarizer obtained by bonding a protective film to a polarizer using the adhesive composition, and the polarizer Manufacturing method. The present invention also relates to an optical member and a liquid crystal display device using the polarizing plate.

A polarizing plate can be used as one of the optical components constituting a liquid crystal display device. A polarizing plate is usually incorporated in a liquid crystal display device in a state where protective films are laminated on both sides of a polarizer, and is used. Although it is also known that a protective film is provided only on one side of the polarizer, in many cases, on the other side, not only the protective film, but other layers with optical functions also serve as protective films. Instead, fit. In addition, as a method for producing a polarizer, a method of subjecting a uniaxially stretched polyvinyl alcohol resin film dyed with a dichroic dye to boric acid treatment, washing with water, and then drying is widely known.

Usually, immediately after the above-mentioned water washing and drying, a protective film is attached to the polarizer. This is because the physical strength of the polarizer after drying is very weak, and when it is wound up, problems such as cracking in the processing direction occur. Therefore, the polarizer after drying is usually immediately coated with water The adhesive is then bonded to the protective film simultaneously on both sides via the adhesive. Generally, as the protective film, a triethylammonium cellulose film having a thickness of 30 to 120 μm is used.

In order to attach a polarizer and a protective film, especially a polarizer to a protective film containing a triethyl cellulose film, a polyvinyl alcohol-based adhesive is often used, but attempts have been made to use a urethane-based adhesive instead. Then agent. For example, Japanese Unexamined Patent Publication No. 7-20617 (Patent Document 1) describes that a urethane prepolymer is used as an adhesive, and a polarizer having a high water content and a cellulose acetate-based protective film such as three Acetyl cellulose film followed.

On the other hand, due to the high moisture permeability of triethyl cellulose, the polarizing plate obtained by laminating the resin film as a protective film has the following problems: under humid and hot conditions, such as at a temperature of 70 ° C and a relative humidity of 90% Causes deterioration under conditions. Therefore, a method has also been proposed in which a resin film having a lower moisture permeability than a triethylammonium cellulose film is used as a protective film to solve the related problems. For example, it is known to use an amorphous polyolefin resin as a protective film. Protective film. Specifically, a thermoplastic saturated norbornene-based resin sheet layer is laminated on at least one surface of the polarizer as a protective film, which is described in Japanese Patent Application Laid-Open No. 6-51117 (Patent Document 2).

When pasting such a protective film with low moisture permeability using a conventional device, an adhesive using water as a main solvent, for example, an aqueous solution of polyvinyl alcohol, is used to attach the protective film to the polarized light of polyvinyl alcohol. In the case of a sheet, and then the solvent is dried, that is, in the case of so-called wet lamination, there is a failure to obtain sufficient adhesion strength, or the appearance It becomes a problem such as bad. The reason for this is that films with low moisture permeability are generally more hydrophobic than triethyl cellulose cellulose films, and because the moisture permeability is low, water as a solvent cannot be sufficiently dried.

Therefore, in Japanese Patent Application Laid-Open No. 2000-321432 (Patent Document 3), it is proposed that a polyvinyl alcohol-based polarizer and a protective film containing a thermoplastic saturated norbornene-based resin are bonded using a polyurethane-based adhesive. Go on. However, the polyurethane adhesive has a problem that it takes a long time to harden, and the adhesive force may not be said to be sufficient.

On the other hand, it is also known that different types of protective films are bonded to both sides of a polarizer. For example, Japanese Patent Application Laid-Open No. 2002-174729 (Patent Document 4) proposes the following: On one side of the polarizer, a protective film containing an amorphous polyolefin-based resin is bonded, and on the other side, a protective film containing a resin different from the amorphous polyolefin-based resin, for example, triethylammonium cellulose, is bonded. ; Japanese Patent Application Laid-Open No. 2005-208456 (Patent Document 5) proposes that, on one side of a polarizing film containing a polyvinyl alcohol resin, an aqueous first containing a specific urethane resin is used. A cycloolefin-based resin film is laminated with an adhesive, and a cellulose acetate-based resin film is laminated on the other side with a second water-based adhesive different from the first adhesive, for example, an aqueous solution of a polyvinyl alcohol-based resin.

The resin referred to as an amorphous polyolefin-based resin in the above-mentioned Patent Document 4 and the cycloolefin-based resin in the above-mentioned Patent Document 5 is a resin containing norbornene, a derivative thereof, and dimethyl bridge octahydrogen. Monomer units of polycyclic cycloolefins such as naphthalene, and When a double bond remains, a thermoplastic resin obtained by hydrogenating it is preferred.

In addition, Japanese Patent Application Laid-Open No. 2004-245925 (Patent Document 6) discloses an adhesive containing an epoxy resin that does not contain an aromatic ring as a main component, and it is proposed that the adhesive is irradiated with active energy rays and cation polymerization is performed. Follow the method of polarizer and protective film. It is clear that the epoxy-based adhesive disclosed here is particularly effective for bonding various transparent resin films typified by amorphous polyolefin resins and cellulose resins to polarizers. When an acrylic resin is used as a protective film, the adhesive force may not be sufficient.

Therefore, the present inventors have developed a low-viscosity photocurable adhesive, which is selected from acrylic resins, polyester resins, polycarbonate resins, and amorphous polyolefin resins. When a low-permeability resin film is used as a protective film of a polarizer, a good adhesion is exhibited in a short time step. As a result, it was found that a composition containing a glycidyl ether type epoxy resin having an aromatic ring and an oxycyclobutane compound exhibits good adhesion, and is particularly effective when containing 5 to 25% by weight of a In the case of acrylate-based monomers, high adhesion and durability are shown (Patent Document 7). However, as for this adhesive, although the production step itself may be a short time step of light irradiation, there is a problem that sufficient adhesive force does not appear unless the film is wound up after a certain period of time. Therefore, there is a problem that it is difficult to perform thin film processing after light irradiation in a production step.

The present inventors have made various As a result of investigation, it was found that a photocurable adhesive composition containing an alicyclic epoxy compound, a specific poly (meth) acrylate, a photocationic polymerization initiator, and oxycyclobutanol is effective (Patent Document 8).

This adhesive composition is a photocurable adhesive for polarizing plates which is excellent not only in adhesion and durability but also in productivity.

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Unexamined Patent Publication No. 7-20617

Patent Document 2: Japanese Patent Application Laid-Open No. 6-51117

Patent Document 3: Japanese Patent Application Laid-Open No. 2000-321432

Patent Document 4: Japanese Patent Application Laid-Open No. 2002-174729

Patent Document 5: Japanese Patent Application Laid-Open No. 2005-208456

Patent Document 6: Japanese Patent Application Laid-Open No. 2004-245925

Patent Document 7: Japanese Patent Application Laid-Open No. 2010-209126

Patent Document 8: Japanese Patent Application Publication No. 2012-140610

However, in the adhesive of the aforementioned Patent Document 8, it was found that when a protective film made of an acrylic resin and a polarizer were adhered, a humidity and heat resistance test was performed in a high-temperature and high-humidity environment (for example, 60 ° C 90%). After that, the peel adhesion force immediately after returning to the normal environment (for example, 23 ° C and 50%) is quite low.

Regarding the reduction of the adhesive force, when the protective film made of acrylic resin is peeled when left in a normal environment for 15 hours, the adhesive force is peeled off. The force is restored to the extent that the protective film has material damage. In addition, even after the end of the moist heat resistance test, the protective film was not peeled by the force (force in the shearing direction or the vertical direction) applied in the form of a product in which a polarizing plate was attached to glass. However, when a worst case such as exposure to a high-temperature, high-humidity environment during transportation of a polarizing plate, and immediately entering a processing step is envisaged, it is expected that the peel strength immediately after the end of the moist-heat resistance test is also improved.

When the acrylic resin protective film and the polarizer are adhered, the acrylic resin film is subjected to a peeling test when the polarizer is attached to a plate such as glass, or both films are bent. In the T-type peeling test, a good adhesive force was shown. However, in the peeling test in which an acrylic resin film was attached to a plate such as glass and the polarizer was bent, there was a problem that the adhesive force was significantly reduced. Therefore, peeling may occur in the processing steps of the polarizing plate and the like when a strong force for bending the polarizer is applied to the end portion. In order to prevent such problems, it is required to develop an adhesive which shows a good adhesive force even in a peeling test in which an acrylic resin film is fixed to a plate and a polarizer is bent.

The problem to be solved by the present invention is to provide a photocurable adhesive, which is suitable for resin films with low moisture permeability selected from polyester resins, polycarbonate resins, acrylic resins, and amorphous polyolefin resins. In the case of a protective film, the hardening property is also excellent, the final adhesion after a certain period of time is also good, and no problems such as poor appearance are caused after the durability test. The adhesion after the moist heat resistance test is also good. Low viscosity. Further, an adhesive is provided which adheres a protective film and a polarizer made of acrylic resin, A resin-like protective film is attached to the board to apply a force to bend the polarizer, and also exhibits excellent adhesion.

Here, the subject of this invention is providing the adhesive agent which solves the said subject matter even if the humidity at the time of apply | coating an adhesive agent is high.

Another object of the present invention is to provide an optical member capable of forming a liquid crystal display device with excellent reliability by using a polarizing plate using the adhesive, and further to apply the same to a liquid crystal display device.

That is, the present invention provides a photocurable adhesive composition for use on a polarizer including a polyvinyl alcohol-based resin film, and further comprising a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin. The protective film of the transparent resin film selected from the group consisting of resin-like resins is characterized by containing the following components: (A) a poly (meth) acrylate of a polyhydric alcohol having 2 to 15 carbon atoms, and (B) a carbon atom Polyglycidyl ether of a polyhydric alcohol having a number of 2 to 10, (C) a compound having a molecular weight of 500 or less having two or more oxocyclobutane groups in one molecule, and (D) a polymer comprising ( d1) a compound having an epoxy group and an ethylenically unsaturated group [hereinafter referred to as "monomer (d1)"], (d2) a compound having a hydrocarbon group having 1 to 10 carbon atoms and one methacryl group [hereinafter "Monomer (d2)"] and (d3) monomers (d1) and (d2), if necessary, compounds having one ethylenically unsaturated group [hereinafter referred to as "monomer (d3)"] As a constituent monomer unit, a polymer produced by polymerizing these monomers at high temperature, among which glass Temperature shift (hereinafter, referred to as "Tg") less than 20 ℃, weight average molecular weight (hereinafter referred to as " Mw ") is 1,000 to 30,000, (E) a photocationic polymerization initiator, and the content ratio of the aforementioned components (A) to (E) in the composition is:

(A) Ingredient: 5 ~ 50% by weight

(B) Ingredient: 5 ~ 45% by weight

(C) Composition: 5 ~ 45% by weight

(D) Ingredient: 1 ~ 25% by weight

(E) Ingredient: 0.5 to 10% by weight.

The component (A) is preferably a di (meth) acrylate of a diol having 2 to 10 carbon atoms. The (meth) acrylate is more preferably an acrylate.

The component (B) is preferably a diglycidyl ether of a diol having 2 to 10 carbon atoms (except for a polyether diol having an alkylene oxide unit repeating number of 3 or more).

The component (C) is preferably an oxetane compound represented by the following formula (1).

The preferable content ratios of (A) component, (B) component, (C) component, (D) component, and (E) component are 10 to 45 weight% and 5 to 35 weight% in the composition, respectively. , 5 to 35% by weight, 2 to 20% by weight, and 2 to 6% by weight.

As (D) component, it is preferable that 5 to 95 weight% of monomers (d1) and 5 to 95 weight% of monomers (d2) are contained in all the constituent monomer units. And a polymer of 0 to 80% by weight of the monomer (d3).

As component (D), it is preferable that all constituent monomer units include 0 to 60% by weight of styrene or 0 to 40% by weight of a hydrocarbon group having 1 to 10 carbon atoms and one acrylamido group. A polymer (hereinafter referred to as "monofunctional acrylate") as a monomer (d3).

The component (D) preferably contains 10 to 60% by weight of glycidyl methacrylate as a monomer (d1) and 10 to 80% by weight of methyl in all constituent monomer units. A polymer obtained by using methyl acrylate as a monomer (d2) and containing 1 to 50% by weight of styrene as a monomer (d3) and polymerizing at a temperature of 160 ° C. or higher.

In addition, as another preferred example, the component (D) preferably contains 10 to 60% by weight of glycidyl methacrylate as the monomer (d1) in the entire constituent monomer units, and contains 10 to 80% by weight. % Methyl methacrylate as monomer (d2), and monofunctional acrylate containing 1 to 30% by weight of a hydrocarbon group having 1 to 10 carbon atoms as monomer (d3), performed at a temperature of 160 ° C or higher Polymer obtained by high temperature polymerization.

Regarding the radically polymerizable components such as the (A) component contained in these photocurable adhesive composition, the (E) component can be hardened by the radical generated when the component is decomposed by light, but in order to reduce the A sufficient reaction rate is obtained by the irradiation amount, and it is preferable to contain a photoradical polymerization initiator as a (F) component in the ratio of 10 weight% or less.

Moreover, in these photocurable adhesive composition, in order to obtain the coating surface excellent in smoothness, it is preferable that the composition contains a leveling agent as a (G) component in 0.01 to 0.5 weight%.

In addition, according to the present invention, a polarizing plate is provided. A protective film containing a transparent resin film selected from polyester resins, polycarbonate resins, acrylic resins, and amorphous polyolefin resins is bonded to a polarizer containing a polyvinyl alcohol resin film with an adhesive. The resulting polarizing plate, wherein the adhesive contains any one of the photocurable adhesive compositions described above.

The polarizing plate can be manufactured by the following method. The method includes the following steps: an adhesive coating step, applying at least one of the bonding surfaces between the polarizer and the protective film, and applying any one of the photocurable adhesives described above. Composition; bonding step, bonding a polarizer and a protective film through the obtained adhesive layer; hardening step, bonding the photohardenability in a state where the polarizer and a protective film are bonded through the adhesive layer The agent composition is hardened. Specifically, a method can be adopted in which the above-mentioned photocurable adhesive composition that is not cured is applied to a polarizer, a protective film is adhered to the application surface of the adhesive composition, and then the adhesive composition is cured to Method for forming an adhesive layer; coating the uncured photocurable adhesive composition on a protective film, attaching a polarizer to the surface of the adhesive composition coating surface, and curing the adhesive composition Method for adhering an adhesive layer; casting the above-mentioned light-curable adhesive composition that is not cured between a polarizer and a protective film, and sandwiching the adhesive composition of the polarizer and the protective film with a roller or the like to hold the adhesive composition A method of uniformly pressing and spreading, pressing while pressing, and then curing the adhesive composition to form an adhesive layer, and the like.

According to the present invention, there is further provided an optical member comprising the above-mentioned polarizing plate and other optical layers displaying optical functions. The other optical layer in this case preferably includes a retardation plate. Also provide one A liquid crystal display device is obtained by disposing the optical member on one or both sides of a liquid crystal cell.

The photocurable adhesive composition of the present invention is used for the production of polarized light of a resin film having a low moisture permeability selected from polyester resins, polycarbonate resins, acrylic resins, and amorphous polyolefin resins as a protective film. In the case of a board, even if the humidity of the coating environment is high, the hardening is excellent, the final adhesion after a certain period of time is good, and the appearance does not cause problems such as appearance after the durability test. Furthermore, the adhesion after the end of the moist heat resistance test Excellent.

The adhesive composition of the present invention is particularly useful when the protective film is made of an acrylic resin. In addition, regarding the adhesive composition of the present invention, when the acrylic resin and the polarizer are adhered, the peel strength is reduced in a peel test, that is, the polarizer is bent by fixing the acrylic resin on a smooth plate. In the case of peeling test, it also showed good adhesion. Therefore, it is also excellent in that it is difficult to peel off in a processing step.

In addition, since the adhesive composition of the present invention has a very low viscosity, it is easy to apply thinly and adhere without defects. Regarding a polarizing plate obtained by bonding a polarizer and a protective film with the adhesive composition, not only the adhesive composition is hardened by a short time step such as light irradiation, but also a certain intensity can be obtained immediately after light irradiation. This makes it possible to manufacture with high productivity.

Furthermore, an optical member obtained by combining this polarizing plate with another optical layer can form a liquid crystal display device having excellent reliability.

Hereinafter, the present invention will be described in detail. In the present invention, when a protective film containing a transparent resin film is attached to a polarizer containing a polyvinyl alcohol-based resin film, a photocurable adhesive composition having a specific composition is used. A polarizing plate can be obtained by bonding a polarizer and a protective film through a photocurable adhesive composition like this. An optical member can be manufactured by laminating this polarizing plate with another optical layer which has an optical function. In addition, by disposing the optical member on at least one side of the liquid crystal cell, a liquid crystal display device can be manufactured. Hereinafter, the photocurable adhesive composition, the polarizing plate, the manufacturing method of a polarizing plate, an optical member, and a liquid crystal display device are demonstrated in order.

[Photocurable adhesive composition]

In the present invention, in order to attach a polarizer and a protective film, a photocurable adhesive composition having a specific composition is used. Hereinafter, this photocurable adhesive composition may be simply referred to as "photocurable adhesive" or "composition". The photocurable adhesive of the present invention is a photocurable adhesive that must contain the following five components (A), (B), (C), (D), and (E).

(A) Poly (meth) acrylate of a polyhydric alcohol having 2 to 15 carbon atoms

(B) Polyglycidyl ether of a polyhydric alcohol having 2 to 10 carbon atoms

(C) A compound having a molecular weight of 500 or less having two or more oxocyclobutane groups in one molecule

(D) a polymer comprising a monomer (d1), a monomer (d2), and The monomer (d3) as a polymer constituting the monomer units is a polymer produced by polymerizing these monomers at a high temperature, and the Tg is 20 ° C or higher and the Mw is 1,000 to 30,000.

(E) Photocationic polymerization initiator

In the present specification, (meth) acrylate means acrylate or methacrylate, and (meth) acrylfluorenyl means acrylfluorenyl or methacrylfluorenyl.

In this specification, the poly (meth) acrylate of (A) is also referred to as "(A) component" or "poly (meth) acrylate (A)", and the epoxy of (B) is also referred to The compound is referred to as "(B) component" or "epoxy compound (B)", and the oxycyclobutane compound (C) is also referred to as "(C) component" or "oxycyclobutane compound (C)" The polymer having an epoxy group in (D) is also referred to as "(D) component", and the photocationic polymerization initiator in (E) is also referred to as "(E) component" or "photocationic polymerization initiation" Agent (E) ".

Regarding the content ratio in the composition of the components (A) to (E), based on the entire composition, (A) component is 5 to 50% by weight, (B) component is 5 to 45% by weight, and (C) component It is 5 to 45% by weight, (D) component is 1 to 25% by weight, and (E) component is 0.5 to 10% by weight.

The photocurable adhesive may optionally contain a photoradical polymerization initiator as the (F) component, and is preferably set to a content ratio of 10% by weight or less. A leveling agent may be contained as the (G) component.

In this specification, the photo-radical polymerization initiator of (F) is also called "(F) component" or "photo-radical polymerization initiator (F)", and the leveling agent of (G) is also called "(G) component" or "leveling agent (G)".

<Poly (meth) acrylate (A)>

In the photocurable adhesive of the present invention, the poly (meth) acrylate which is the component (A) is a poly (meth) acrylate which is a polyhydric alcohol having 2 to 15 carbon atoms.

The durability of the (meth) acrylic acid ester having a number of (meth) acrylfluorene groups in the molecule of 1 is likely to be insufficient, such as resistance to cold and heat cycles.

By using the component (A), the viscosity of the composition is reduced, and the adhesion to the protective film and the durability are excellent. Here, as (A) component, the di (meth) acrylate of the diol with 2-10 carbon atoms is more preferable from a viewpoint of low viscosity, adhesive force, and durability. The (meth) acrylate is preferably an acrylate from the viewpoint of curability.

Specific examples of the component (A) include neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 3-methyl-1,5-pentanediol. Di (meth) acrylate, dimethylolcyclohexane di (meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, 1,9- Nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, diethylene glycol di (Meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, dimethylol tricyclodecane bis (methyl) Acrylate), trimethylolpropane tri (meth) acrylate, bis (trimethylolpropane) tetra (meth) acrylate, pentaerythritol tri or tetra (meth) acrylate, dipentaerythritol five or six (Meth) acrylates, di (meth) acrylates of hydrogenated bisphenol A, and the like.

The component (A) may have an ester skeleton and an isocyanurate skeleton. As Specific examples of the compound having an ester skeleton include an esterification reaction product of neopentyl glycol, hydroxytrimethylacetic acid, and (meth) acrylic acid. Examples of the compound having an isocyanurate skeleton include Diisotricyanic acid alkylene oxide adducts of di or tri (meth) acrylates and the like.

Among these, 1,6-hexanediol di (meth) acrylate, neopentyl glycol, and hydroxytrimethyl are particularly preferable from the viewpoints of low viscosity, excellent adhesion and durability, and low odor. Esterification reaction product of acetic acid and (meth) acrylic acid.

The content ratio of (A) component is the range of 5-50 weight% based on the whole composition. By setting it as this ratio, hardenability, final adhesive force, and durability can be made favorable. In addition, by setting the content ratio of the (A) component to a range of 10 to 45% by weight, the adhesive force can be made better.

<Epoxy Compound (B)>

In the photocurable adhesive of the present invention, the epoxy compound to be the component (B) is a polyglycidyl ether of a polyhydric alcohol having 2 to 10 carbon atoms.

The epoxy compound having the number of glycidyl ether groups in the molecule of 1 is likely to be insufficient in durability such as adhesive force and cold-heat cycle resistance.

By using the component (B), the viscosity of the composition is reduced, and the adhesion to the polarizer is excellent. Here, as the component (B), a diol having 2 to 10 carbon atoms (but an alkylene oxide unit) is more preferable from the viewpoint that the composition can be made low in viscosity and excellent in adhesion. (Except for polyether glycols having a repeat number of 3 or more).

Specific examples of the component (B) include ethylene glycol dicondensation Hydroglyceryl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, dihydroxyl Methylcyclohexane diglycidyl ether, 1,9-nonanediol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, hydroquinone diglycidyl ether, Resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tri- or tetraglycidyl ether, and di- or triglycidyl groups of ethylene isocyanate adducts Ether, etc.

Among these, alkanediol diglycidyl ether having 2 to 10 carbon atoms is particularly preferred from the viewpoint of low viscosity and adhesion.

The content ratio of (B) component is the range of 5 to 45 weight% based on the whole composition. By setting this ratio, the hardenability, the final adhesive force, and the adhesive force after a moist heat resistance test can be made favorable. From this viewpoint, the content ratio of the component (B) is preferably 5 to 35% by weight, more preferably 10 to 35% by weight, and still more preferably 15 to 35% by weight.

<Oxycyclobutane compound (C)>

In the photocurable adhesive of the present invention, the oxocyclobutane compound serving as the component (C) is a compound having a molecular weight of 500 or less in two molecules in one molecule.

Specific examples of the component (C) include bis [(3-ethyloxycyclobutane-3-yl) methyl] ether and bis [(3-methyloxycyclobutane-3-yl) methyl ] Ether, bis [(oxycyclobutane-3-yl) methyl] ether, 1,4-bis {[(3-ethyloxycyclobutane-3-yl) methoxy] methyl} benzene, 1,4-bis [(3-ethyloxycyclobutane-3-yl) methoxy] benzene, 1,3-bis [(3-ethyloxycyclobutane-3-yl) methoxy] Benzene, 1,2- Bis [(3-ethyloxycyclobutane-3-yl) methoxy] benzene, 4,4'-bis [(3-ethyloxycyclobutane-3-yl) methoxy] biphenyl, 2,2'-bis [(3-ethyloxycyclobutane-3-yl) methoxy] biphenyl, 1,1,1-reference [(3-ethyloxycyclobutane-3-yl) Methoxymethyl] propane, 1,2-bis [(3-ethyloxycyclobutane-3-yl) methoxy] ethane, 2,2-bis {[(3-ethyloxycyclobutane Alk-3-yl) methoxy] methyl} propane, 1,2-bis [(3-ethyloxycyclobutane-3-yl) methoxy] propane, 1,4-bis [(3- Ethyloxycyclobutane-3-yl) methoxy] butane and 1,6-bis [(3-ethyloxycyclobutane-3-yl) methoxy] hexane and the like.

The component (C) is more preferably a molecular weight of 150 to 400 having two oxocyclobutane groups in one molecule from the viewpoint that the obtained composition has a low viscosity and the viewpoint of excellent adhesion of the cured product. The compound has a more preferable molecular weight in the range of 150 to 300.

The component (C) is particularly preferably bis [(3-ethyloxycyclobutane-3-yl) methyl] ether, that is, an oxycyclobutane compound represented by the following formula (1).

The content ratio of (C) component is the range of 5 to 45 weight% based on the whole composition. By setting this ratio, the hardenability, the final adhesive force, the adhesive force after a moist heat resistance test, and durability can be made favorable. Regarding the component (C), by admixing in an appropriate amount, it contributes to the improvement of the adhesion to various substrates, and in particular, greatly improves the adhesion to the acrylic resin protective film.

When the content ratio of the component (C) is less than 5% by weight, the adhesive force shortly after the light irradiation and the final adhesive force are insufficient. In addition, more than At 45% by weight, the adhesion to the polarizer is reduced.

The content ratio of the component (C) is preferably from 5 to 35% by weight, and more preferably from 10 to 30% by weight, from the viewpoint that the adhesive force becomes more excellent.

<Polymer (D) having an epoxy group>

In the photocurable adhesive of the present invention, by including the component (D), even if the humidity at the time of applying the adhesive is high, the curability and the adhesive force can be made good.

(D) As long as it is a polymer containing the monomer (d1), the monomer (d2), and the monomer (d3) as a monomer unit as needed, and these monomers are polymerized at high temperature, Polymers with a Tg of 20 ° C or higher and a Mw of 1,000 to 30,000, various polymers can be used.

The Tg of the component (D) is 20 ° C or higher, preferably 30 ° C or higher, and more preferably 40 to 100 ° C. The adhesive force of the polymer having a Tg of less than 20 ° C becomes insufficient.

In addition, in this invention, Tg means the value measured using the differential scanning calorimeter (DSC) at the temperature rise rate of 10 degree-C / min.

The Mw of the component (D) is 1,000 to 30,000, preferably 3,000 to 20,000, and more preferably 5,000 to 15,000. When the Mw of the component (D) is less than 1,000, the adhesion between the polarizer and the polarizer protective film is reduced. When the Mw of the component (D) exceeds 30,000, the coatability decreases.

In the present invention, Mw means a weight average molecular weight obtained by converting a molecular weight measured by GPC into a polystyrene conversion.

The component (D) is a polymer obtained by high-temperature polymerization.

(D) The component is a polymer with a low Mw. When manufacturing such a polymer with a low Mw method, it is usually necessary to increase a chain transfer agent and a polymerization initiator. When a polymer using a large amount of a chain transfer agent is used, the cation hardenability and adhesive force of the composition are easily reduced. When a polymer using a large amount of a polymerization initiator is used, the storage stability of the composition is easily reduced. . Therefore, a polymer produced by high-temperature polymerization that does not require a large amount of a chain transfer agent or a polymerization initiator is required.

The high-temperature polymerization temperature is preferably 160 ° C or higher, more preferably 160-350 ° C, and particularly preferably 180-300 ° C.

Among the high-temperature polymerizations, continuous high-temperature polymerization is preferred. Regarding continuous polymerization at high temperature, not only is it excellent in productivity, but it is also difficult to form a composition distribution in a copolymer product, so it has advantages such as excellent compatibility.

The high-temperature continuous polymerization can be carried out by a known method (for example, Japanese Patent Application Publication No. 57-502171, Japanese Patent Application Publication No. 59-6207, and Japanese Patent Application Publication No. 60-215007).

Specifically, a method is described in which a pressurizable reactor is filled with a solvent, the temperature is set to a predetermined temperature under pressure, and then a monomer containing the polymerization solvent or a polymerization solvent or polymerization initiation as required is supplied at a constant supply rate. The monomer mixture of the agent was supplied to the reactor, and the reaction solution was withdrawn in an amount commensurate with the supply amount of the monomer mixture.

The component (D) is a polymer in which the monomer (d1) and the monomer (d2) are essential constituent monomer units, and is a polymer having an epoxy group, and is compatible with the component (B) as a cation hardening compound and (C) The components are copolymerized.

The monomer (d1) is a compound having an epoxy group and an ethylenically unsaturated group.

Examples of the ethylenically unsaturated group in the monomer (d1) include a vinyl group and a (meth) acrylfluorenyl group.

Specific examples of the monomer (d1) include glycidyl (meth) acrylate and 3,4-epoxycyclohexyl methyl (meth) acrylate.

(D1) Particularly preferred is glycidyl methacrylate.

The monomer (d2) is a compound having a hydrocarbon group having 1 to 10 carbon atoms, and is a compound having one methacrylfluorenyl group (hereinafter, referred to as "monofunctional methacrylate").

Specific examples of the monomer (d2) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, and secondary butyl methacrylate. Tertiary butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate Esters, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate, benzyl methacrylate, and the like.

As the monomer (d2), among these compounds, monofunctional methacrylates having a hydrocarbon group of 1 to 6 carbon atoms are more preferred, and methyl methacrylate, ethyl methacrylate, and methyl methacrylate are more preferred. Cyclohexyl acrylate and benzyl methacrylate, particularly preferably methyl methacrylate.

As the constituent monomer unit, the weight ratio of the monomer (d1) to the monomer (d2) contained in the component (D) is preferably 5 to 95% by weight and 5 to 95% of the total constituent monomer units, respectively. 95% by weight. By setting it as this range, even if an adhesive composition is apply | coated under high humidity, an adhesive force is excellent.

As the constituting monomer unit, a better weight ratio of the monomer (d1) and the monomer (d2) contained in the component (D) is 10 to 60% by weight and 10 in the entire constituting monomer unit, respectively. ~ 80% by weight, more preferably 20 ~ 50% by weight and 20 ~ 70% by weight, respectively. In addition, when the total of the monomers (d1) and (d2) is less than 100% by weight, it means a polymer containing the monomer (d3) as a constituent monomer.

As the component (D), a monomer (d3) other than the monomer (d1) and the monomer (d2) as a compound having one ethylenically unsaturated group may be included as a constituent monomer unit as necessary.

The weight ratio of the monomer (d3) contained in the component (D) is preferably 0 to 80% by weight, and more preferably 0 to 60% by weight in the entire constituent monomer units.

Examples of the ethylenically unsaturated group in the monomer (d3) include a vinyl group and a (meth) acrylfluorenyl group.

As the monomer (d3), as long as it is a monomer other than the monomer (d1) and the monomer (d2), various compounds can be used, and examples thereof include aromatic groups-containing ethylene such as styrene and α-methylstyrene. Compounds (e.g., "monofunctional acrylate"), (meth) acrylonitrile, (meth) acrylamido, and the like, other than a base compound, a monomer (d1) other than a monomer (d1).

As the monomer (d3), among these compounds, styrene or / and a monofunctional acrylate having a hydrocarbon group having 1 to 10 carbon atoms is more preferred.

When the monomer (d3) contains styrene, the content of the styrene contained in the component (D) is preferably 60% by weight or less (0 to 60% by weight) in all the constituent monomer units, It is more preferably 1 to 50% by weight, even more preferably 5 to 45% by weight, and particularly preferably 10 to 40% by weight. By setting With this content ratio, the adhesive force when the adhesive composition is applied under high humidity becomes more excellent.

When the monomer (d3) contains a monofunctional acrylate having a hydrocarbon group having 1 to 10 carbon atoms, specific examples of the monofunctional acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, and acrylic acid. Isopropyl ester, butyl acrylate, secondary butyl acrylate, tertiary butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isooctyl acrylate , Nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate, and benzyl acrylate.

Among these compounds, methyl acrylate, ethyl acrylate, cyclohexyl acrylate, and benzyl acrylate are preferred, and methyl acrylate is more preferred.

When the monomer (d3) contains a monofunctional acrylate having a hydrocarbon group having 1 to 10 carbon atoms, the content of the monofunctional acrylate having a hydrocarbon group having 1 to 10 carbon atoms contained in the component (D) is contained. The proportion is preferably 40% by weight or less (0 to 40% by weight), more preferably 1 to 30% by weight, and still more preferably 5 to 25% by weight in all constituent monomer units. By setting this content ratio, the adhesive force at the time of apply | coating an adhesive composition under high humidity becomes more excellent.

As a more preferable example of the component (D), it is preferable to include 10 to 60% by weight of glycidyl methacrylate as the monomer (d1), and 10 to 80% by weight of all the constituent monomer units. A polymer obtained by using methyl methacrylate as a monomer (d2), and containing 1 to 50% by weight of styrene as a monomer (d3), and polymerizing at a temperature of 160 ° C. or higher.

In addition, as another preferred example, the component (D) preferably contains 10 to 60% by weight of glycidyl methacrylate as the monomer (d1) in the entire constituent monomer units, and contains 10 to 80% by weight. % Methyl methacrylate as monomer (d2), and monofunctional acrylate containing 1 to 30% by weight of a hydrocarbon group having 1 to 10 carbon atoms as monomer (d3), performed at a temperature of 160 ° C or higher Polymer obtained by high temperature polymerization.

Regarding the content ratio of the (D) component contained in the adhesive composition of the present invention, it is required to be 1 to 25% by weight, preferably 2 to 20% by weight, and more preferably 5 to 15 based on the entire composition. weight%. By containing the (D) component in a ratio of 1 to 25% by weight, the adhesive force after the light irradiation, the final adhesive force, and the adhesive force after the moist heat resistance test can be made good.

<Photocationic polymerization initiator (E)>

The photocurable adhesive of the present invention contains the epoxy compound (B), the oxocyclobutane compound (C), the polymer (D) having an epoxy group, and a ring described later as necessary, as described above. An oxygen compound and an oxycyclobutane compound are used as a cation-hardening component, and a photocationic polymerization initiator is blended as a component (E). This photocationic polymerization initiator irradiates active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams to generate a cationic species or a Lewis acid, and initiates a polymerization reaction of an epoxy group and an oxycyclobutane group.

By blending a photocationic polymerization initiator as the (E) component, hardening at room temperature can be achieved, the necessity of considering the heat resistance of the polarizer, and the strain due to expansion or contraction can be reduced, and the protective film can be adhered well . In addition, photo-cationic polymerization initiators use active energy It acts as a catalyst when it is irradiated with light, so even if it is mixed with epoxy compound (B), oxocyclobutane compound (C), epoxy group-containing polymer (D), epoxy compound and oxygen Butane compounds are also excellent in storage stability and workability. Examples of the compound that generates a cationic species or a Lewis acid by irradiating active energy rays include, for example, an aromatic diazonium salt, an aromatic iodonium salt, an onium salt of an aromatic sulfonium salt, and an iron-propadiene complex Wait.

Examples of the aromatic diazonium salt include the following compounds.

Phenyldiazonium hexafluoroantimonate, phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroborate and the like.

Examples of the aromatic iodonium salt include the following compounds.

Diphenyliodonium (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, bis (4-nonylphenyl) iodonium hexafluoro Phosphate, etc.

Examples of the aromatic sulfonium salts include the following compounds.

Triphenylphosphonium hexafluorophosphate, triphenylphosphonium hexafluoroantimonate, triphenylphosphonium (pentafluorophenyl) borate, 4,4'-bis (diphenylsulfonium) diphenylsulfide Ether bishexafluorophosphate, 4,4'-bis [bis (β-hydroxyethoxy) phenylsulfonium] diphenylsulfide dihexafluoroantimonate, 4,4'-bis [bis (β-hydroxyethoxy) phenylsulfonium] diphenylsulfide dihexafluorophosphate, 7- [bis (p-tolylmethyl) sulfonium] -2-isopropyl Thioxanthone hexafluoroantimonate, 7- [bis (p-tolylmethyl) sulfonium] -2-isopropylthioxanthone (pentafluorophenyl) borate, 4-phenylcarbonyl- 4'-diphenylsulfonium-diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonium-diphenylsulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4'-bis (p-tolylmethyl) sulfonium-diphenylsulfide (pentafluorophenyl) borate and the like.

Examples of the iron-propadiene complex include the following compounds.

Xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) -ginseng ( Trifluoromethylsulfonyl) methylate and the like.

These photocationic polymerization initiators may be used alone or in combination of two or more. Among them, the aromatic sulfonium salt is particularly preferably used because it has ultraviolet absorption characteristics in a wavelength range of 300 nm or more, so that a hardened product having excellent hardenability, good mechanical strength, and adhesive strength can be produced.

As for the (E) component, commercially available products can be easily obtained. For example, they can be listed according to their product names: "Kayarad PCI-220", "Kayarad PCI-620" (above, manufactured by Nippon Kayaku Co., Ltd.), and "UVI- 6992 '' (The (Dow Chemical Company), "Adekaoptomer SP-150", "Adekaoptomer SP-160" (above, (made by ADEKA)), "CI-5102", "CIT-1370", "CIT-1682", "CIP- 1866S "," CIP-2048S "," CIP-2064S "(above, Japan's Soda Co., Ltd.)," DPI-101 "," DPI-102 "," DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI-102 "," BBI-103 "," BBI-105 "," TPS-101 "," TPS-102 "," TPS- 103 "," TPS-105 "," MDS-103 "," MDS-105 "," DTS-102 "," DTS-103 "(above, manufactured by Midori Kagaku Co., Ltd.)," PI-2074 " (Manufactured by Rhodia), "Irgacure 250", "Irgacure PAG103", "Irgacure PAG108", "Irgacure PAG121", "Irgacure PAG203" (above, made by BASF), "CPI-100P", "CPI-101A", "CPI-210S", "CPI-110P" (above, manufactured by San-Apro Ltd.), etc.

Among these products, propylene carbonate which does not contain a solvent often used as the component (E) is more preferable because it has excellent adhesion to a protective film such as an acrylic resin.

The content ratio of the (E) component is in the range of 0.5 to 10% by weight based on the entire composition. When the proportion is less than 0.5% by weight, the curing of the adhesive becomes insufficient, and the mechanical strength and the bonding strength decrease. On the other hand, when the proportion exceeds 10% by weight, the ionic substance in the cured product may increase. As a result, the hygroscopicity of the hardened material is increased, and the durability is reduced, which is not good. The content ratio of the (E) component is more preferably 2 to 6% by weight. By containing (E) component of 2% by weight or more , So that the adhesive force when the adhesive composition is applied under high humidity becomes more excellent. In addition, by containing the (E) component in an amount of 6% by weight or less, optical properties such as transparency and durability can be made better.

<Photo radical polymerization initiator (F)>

Regarding the radically curable components such as the component (A) contained in the photocurable adhesive of the present invention, the radicals generated when the component (E) is decomposed under the action of light can be used for curing. In order to obtain a sufficient reaction rate, it is preferable to blend a photoradical polymerization initiator as the (F) component. The blending ratio of the (F) component is preferably 10% by weight or less, more preferably 0.1 to 10% by weight, and still more preferably 0.1 to 5% by weight based on the entire composition. When the blending amount exceeds 10% by weight, the durability may be lowered, which is not preferable.

Specific examples of the (F) component include the following compounds.

Like 4'-phenoxy-2,2-dichloroacetophenone, 4'-tertiary butyl-2,2-dichloroacetophenone, 2,2-dimethoxy-2-phenylbenzene Ethyl ketone, 2-methyl-1- (4-methylphenylthio) -2-morpholinylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, α, α-diethoxyphenethyl Ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4 -Dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methylpropan- 1-keto and 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) butane-1-one acetophenone-based photopolymerization initiators; like benzoin, Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin ether photopolymerization initiators of benzoin isobutyl ether; Like benzophenone, methyl benzophenylate, 4-phenylbenzophenone, 4-benzophenydryl-4'-methyldiphenyl sulfide, and 2,4,6-tris Benzophenone-based photopolymerization initiators of methylbenzophenone; like 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1 Thioxanthone-based photopolymerization initiator of -chloro-4-propoxythioxanthone; like 2,4,6-trimethylbenzylidene diphenylphosphine oxide, bis (2,6-dimethoxy Benzyl amidino) -2,4,4-trimethylpentylphosphine oxide and fluorenyl phosphine oxide based on bis (2,4,6-trimethylbenzyl) phenyl phosphine oxide Initiator; like 1- [4- (phenylthio) phenyl] -1,2-octanedione 2- (O-benzidine oxime) oxime. Ester type photopolymerization initiator; camphorquinone and the like.

(F) A component may be used individually by 1 type, and may be used in combination of 2 or more types depending on the desired performance.

In the case of a photoradical polymerization initiator blended with the (F) component, the content ratio is based on the entire composition, preferably 10% by weight or less, more preferably 0.1 to 10% by weight, and even more preferably It is 0.1 to 5% by weight. When the content ratio of the photo radical polymerization initiator (F) is in the above range, sufficient adhesive strength can be obtained, and the hardenability is also excellent.

<Leveling agent (G)>

In the photocurable adhesive of the present invention, a leveling agent containing the (G) component is preferred for the purpose of obtaining a coated surface having excellent smoothness.

Examples of the component (G) include a polysiloxane-based leveling agent and a fluorine-based leveling agent. Various commercially available leveling agents can be used.

A preferable content ratio of the (G) component is 0.01 to 0.5% by weight based on the entire composition. By setting it as the said range, the addition effect of a leveling agent can fully be acquired and it is excellent in adhesiveness.

<Other hardening ingredients>

The photocurable adhesive of the present invention may contain other cation-curable components and radical-curable components in addition to the components (A) to (G) described above.

Examples of the cation-curable component other than the component (B), the component (C), and the component (D) include various epoxy compounds, oxetane compounds, and vinyl ether compounds.

Specific examples of the epoxy compound other than the component (B) and the component (D) include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3, 4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl-3,4-epoxylactone modified products of caprolactone, polycarboxylic acids and 3 1,4-Epoxycyclohexylmethanol esterification or its caprolactone modification, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl group of bisphenol A Ether, phenol novolac epoxy resin, cresol novolac epoxy resin, biphenyl epoxy resin, diglycidyl terephthalate, diglycidyl phthalate, polybutadiene carboxylic acid terminal Addition reaction product of olefin and bisphenol A epoxy resin, dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, polyethylene glycol (repeated number is 6 or more) ) Glycidyl ether, polypropylene glycol (repeated number of 4 or more) diglycidyl ether, polytetramethylene glycol (repeated number of 3 or more) diglycidyl ether, hydrogenated bisphenol A diglycidyl Ether, ring Vegetable oils, 2- (3,4-epoxycyclohexyl) Ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl Methyldimethoxysilane, polybutadiene diglycidyl ether at both terminal hydroxyl groups, internal epoxide of polybutadiene, and epoxidation of a part of double bonds of styrene-butadiene copolymer Compound [for example, "Epoflend" manufactured by Daicel Chemical Industries, Ltd], and a compound obtained by epoxidizing a part of isoprene units of a block copolymer of an ethylene-butene copolymer and polyisoprene (For example, "L-207" manufactured by KRATON).

Specific examples of the oxycyclobutane compound other than the component (C) include alkoxyalkyl-containing compounds such as 3-ethyl-3- (2-ethylhexyloxymethyl) oxycyclobutane. Monofunctional oxycyclobutane, aromatic functional monofunctional oxycyclobutane like 3-ethyl-3-phenoxymethyloxycyclobutane, like 3-ethyl-3-hydroxymethyloxy Hydroxyl-containing monofunctional oxygen cyclobutane of cyclobutane, 3-chloromethyl-3-ethyloxycyclobutane etherified modification of novolac-type phenol resin, 3-[(3-ethyl Oxycyclobutane-3-yl) methoxy] propyltrimethoxysilane, 3-[(3-ethyloxycyclobutane-3-yl) methoxy] propyltriethoxysilane, 3 -[(3-ethyloxycyclobutane-3-yl) methoxy] propyltrialkoxysilane hydrolyzed condensate, 3-ethyloxycyclobutane-3-ylmethanol and silanoltetraol polycondensation Products of condensation reaction of substances.

Specific examples of the vinyl ether compound include cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl. Ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, and the like.

Regarding cations other than (B) component, (C) component, and (D) component The content ratio of the ion-hardening component is preferably less than 30% by weight, and more preferably less than 15% by weight based on the entire composition.

Examples of the radical-curable component other than the component (A) include various compounds, and examples thereof include (meth) acrylates, (meth) acrylamidones, maleimides, and (meth) acrylic acids. , Maleic acid, itaconic acid, (meth) acryl, N-vinyl-2-pyrrolidone, triallyl isotricyanate, divinyl adipate, vinyltrimethoxysilane Wait.

Specific examples of (meth) acrylates having one (meth) acrylfluorenyl group in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate Ester, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, (formyl) Base) isooctyl acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) 4-hydroxybutyl acrylate, cyclohexyl (meth) acrylate, isoamyl (meth) acrylate, dimethylol 1,4-cyclohexane mono (meth) acrylate, (meth) acrylate di Cyclopentane, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, benzyl (meth) acrylate, (meth) alkylene oxide adduct Acrylate, (meth) acrylate of p-cumylphenol alkylene oxide adduct, (meth) acrylate of o-phenylphenol alkylene oxide adduct, nonylphenol alkylene oxide adduct ( (Meth) acrylate, (meth) acrylic acid 2- (Methoxy), ethoxyethoxyethyl (meth) acrylate, (meth) acrylates of alkylene oxide adducts of 2-ethylhexanol, pentanediol mono (meth) acrylic acid Ester, hexanediol mono (meth) propylene Acid ester, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (methyl) Group) acrylate, mono (meth) acrylate of dipropylene glycol, mono (meth) acrylate of tripropylene glycol, mono (meth) acrylate of polypropylene glycol, 2-hydroxy-3-benzene (meth) acrylate Oxypropyl ester, 2-hydroxy-3-butoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl (meth) acrylate, (methyl ) (2-ethyl-2-methyl-1,3-dioxolane-4-yl) methyl acrylate, (2-isobutyl-2-methyl-1,3-methyl methacrylate) Dioxolane-4-yl) methyl ester, (1,4-dioxaspiro [4.5] decane-2-yl) methyl (meth) acrylate, glycidyl (meth) acrylate, (formyl) 3,4-epoxycyclohexyl methyl acrylate, (3-ethyloxycyclobutane-3-yl) methyl (meth) acrylate, 2- (meth) acryloxyethyl isocyanate, Allyl (meth) acrylate, N- (meth) acryloxyethylhexahydroxylylenediamine, N- (meth) acryloxyethyl tetrahydroxylylenediamine , 2- (A ) Acrylic ethoxyethyl hexahydrophthalic acid, 2- (meth) acrylic ethoxyethyl succinic acid, ω-carboxy-polycaprolactone mono (meth) acrylate, 2- (methyl) Acrylic ethoxyethyl acid phosphate, 3- (meth) acrylic ethoxypropyltrimethoxysilane, 3- (meth) acrylic ethoxypropyldimethoxymethylsilane, 3- (Meth) acryloxypropyltriethoxysilane and the like.

As specific examples of (meth) acrylates other than the (A) component having two or more (meth) acrylfluorene groups in the molecule [hereinafter, referred to as "multifunctional (meth) acrylate"], Diethylene glycol (repeated number of 8 or more) di (meth) acrylate, polypropylene glycol (repeated number of 6 or more) di (meth) acrylate, and bis (methyl methacrylate) adduct base ) Acrylate, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and the like. Examples of the polyester (meth) acrylate having three or more (meth) acrylfluorenyl groups include a dendrimer-type (meth) acrylate.

Specific examples of (meth) acrylamide include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and N, N-diethyl (meth) acryl Ammonium amine, N-hydroxymethyl (meth) acrylamide, N- (3-N, N-dimethylaminopropyl) (meth) acrylamide, methylenebis (meth) acryl Fluorenamine, ethylene bis (meth) acrylamide, N, N-diallyl (meth) acrylamide, (meth) acrylfluorenylmorpholine, and the like.

Specific examples of maleimidines include N-methylmaleimide, N-hydroxyethylmaleimide, N-hydroxyethylcitrateimine, and N-hydroxyethyl Carbamate reaction products of citraconimine and isophorone diisocyanate, etc.

The content ratio of the radically curable component other than the component (A) is preferably less than 20% by weight based on the entire composition.

<Other ingredients without hardening properties>

Furthermore, in the photocurable adhesive of the present invention, other components having no hardenability may be arbitrarily blended in a range that does not impair the effects of the present invention. Specific examples include a photosensitizer, a thermal cationic polymerization initiator, and (D ) Polymers other than components, polyol compounds, water, and the like.

Specific examples of the photosensitizer include benzophenone, methyl benzophenylidenebenzoate, 2-isopropylthioxanthone, 9,10-dibutoxyanthracene, and the like. Among these, although there are compounds corresponding to the photoradical polymerization initiator of the component (F), the photosensitizers referred to herein It is a substance which functions as a sensitizer with respect to the photocationic polymerization initiator of (E) component. These can be used individually or in combination of 2 or more types.

The content ratio of the photosensitizer is preferably less than 3% by weight based on the entire composition.

Specific examples of the thermal cationic polymerization initiator include benzylsulfonium salt, thienylium salt, tetrahydrothienylium salt, benzylammonium salt, pyridinium salt, hydrazine salt, carboxylic acid ester, sulfonic acid ester, and amidine Amine, etc. These initiators can be easily obtained from commercial products. For example, "Adekaoputon CP77" and "Adekaoputon CP66" (above, (manufactured by ADEKA)), "CI-2639", and "CI-2624" are all represented by trade names. "(Above, manufactured by Soda Co., Ltd.)," San-Aid SI-60L "," San-Aid SI-80L ", and" San-Aid SI-100L "(above, manufactured by Sanxin Chemical Industry Co., Ltd.) Wait.

The content ratio of the thermal cationic polymerization initiator is preferably less than 3% by weight based on the entire composition.

In the photocurable adhesive of the present invention, a polymer other than the component (D) may be blended for the purpose of improving the adhesive force in a test method for inserting a blade of a cutter [hereinafter, referred to as " (D) 'ingredients "].

Various polymers can be used as the (D) 'component, but for reasons of excellent final adhesion to the polarizer, 60% by weight or more of an acrylic alkane containing an alkyl group having 1 to 10 carbon atoms is preferred. A polymer [hereinafter, referred to as "(D1) 'component"] as a constituent monomer unit with a Mw of 1,000 to 200,000.

As a specific example of an alkyl acrylate containing an alkyl group having 1 to 10 carbon atoms, an alkyl group in a monofunctional acrylate having a hydrocarbon group having 1 to 10 carbon atoms in the monomer (d3) is mentioned. Compounds.

As component (D1) ', if an alkyl acrylate containing an alkyl group having 1 to 10 carbon atoms is used as a constituent monomer unit and 60% by weight or more is contained, the component may be an alkyl methacrylate or other monomer. Copolymer.

The component (D1) 'is preferably a polymer having a Tg of 10 ° C or lower, and more preferably a polymer having a Tg of -80 to 0 ° C. This is due to a change in adhesive force in a test method for inserting a blade of a cutting blade. It is better for high reasons.

(D1) 'component may be a block copolymer of alkyl acrylate, alkyl methacrylate, and other monomers containing an alkyl group having 1 to 10 carbon atoms [hereinafter, referred to as "(D1-1)' ingredient"].

Preferred combinations of the monomers in the (D1-1) 'component include a block polymer having a polyacrylate block unit and a polymethacrylate block unit, and a polyacrylate block Block polymer of block polymer of unit and other monomer, etc.

Among these, a block polymer having a polyacrylate-based block unit and a polymethacrylate-based block unit is preferable, and polybutylacrylate and polymethylmethacrylate are further more preferable as the block polymer. Block polymer of block units.

As the (D1-1) 'component, a component produced by polymerization in accordance with a conventional method using the aforementioned monomer can be used, and examples thereof include a radical polymerization method, a living anion polymerization method, a living radical polymerization method, and the like. Examples of the form of polymerization include a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a block polymerization method.

(D1-1) 'component is commercially available, and Clarity (LA1114, LA2140e, LA2330, LA2250) and the like manufactured by Kuraray Co., Ltd. are listed.

The proportion in the case where the (D) 'component is blended is preferably 1 to 15% by weight, and more preferably 1 to 8% by weight in the composition.

Specific examples of the polyol compound include ethylene glycol, propylene glycol, polyether polyol compounds, polyester polyol compounds, polycaprolactone polyol compounds, polycarbonate polyol compounds, and the like.

The blending ratio of the polyol compound is preferably less than 10% by weight based on the entire composition.

Regarding the viscosity of the photocurable adhesive of the present invention, in order to obtain coatability that can be used in the manufacturing process of a polarizing plate, that is, to obtain a coated surface excellent in smoothness even with a thin film, the viscosity at 25 ° C. is preferably 150mPa. Below s, more preferably 100mPa. s or less. It is more preferably 50 mPa. s or less.

In the photocurable adhesive of the present invention, a small amount of water may be added in order to improve the adhesion to a polarizer having high dryness. In this case, the amount of water to be added is preferably less than 3% by weight, and more preferably less than 1% by weight based on the entire composition.

In addition to these, as long as the effect of the present invention is not impaired, an ion trapping agent, an antioxidant, a light stabilizer, a chain transfer agent, a tackifier, a thermoplastic resin, metal oxide fine particles, an antifoaming agent, and a pigment may be blended. , Organic solvents, etc.

[Polarizer]

The photocurable adhesive described above is used to adhere a protective film to a polarizer containing a polyvinyl alcohol-based resin film, and is preferably used to include A protective film is attached to the polarizer of the polyvinyl alcohol-based resin film that is uniaxially stretched and the dichroic dye is adsorbed and aligned. In this way, the protective film is bonded to the polarizer to form a polarizing plate. That is, the polarizing plate of the present invention is a polarizing plate obtained by laminating a protective film on a polarizer including a polyvinyl alcohol-based resin film that is uniaxially stretched and dichroic dye is adsorbed and aligned. The protective film may be attached to only one side of the polarizer, or may be attached to both sides of the polarizer. When a protective film is bonded to both surfaces of a polarizer, each protective film may be a protective film containing the same kind of resin, or a protective film containing different kinds of resin.

<Polarizer>

The polyvinyl alcohol-based resin constituting the polarizer is obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include, in addition to polyvinyl acetate, a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol resin is preferably in the range of 85 to 100 mol%, and more preferably in the range of 98 to 100 mol%. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal, polyvinyl acetal, etc. obtained by modification with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is preferably in the range of 1,000 to 10,000, and more preferably in the range of 1,500 to 10,000.

The polarizing plate is produced through the following steps: a step of uniaxially stretching such a polyvinyl alcohol-based resin film; a step of dyeing the polyvinyl alcohol-based resin film with a dichroic pigment to adsorb the dichroic pigment; Polyvinyl alcohols to which dichroic pigments are adsorbed by boric acid aqueous solution A step of processing a resin film; a step of washing with water after a treatment with a boric acid aqueous solution; and a uniaxially stretched polyvinyl alcohol-based resin film in which a dichroic dye is subjected to adsorption alignment by performing these steps Membrane steps.

Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, or may be performed after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before or during the boric acid treatment. In addition, it is needless to say that uniaxial stretching may be performed in these multiple stages. For uniaxial stretching, uniaxial stretching may be performed between rolls having different peripheral speeds, or uniaxial stretching may be performed using a hot roll. In addition, it may be dry stretching performed in the air, or wet stretching performed in a state of swelling with a solvent. The stretching ratio is preferably about 4 to 8 times.

In order to dye a polyvinyl alcohol-based resin film with a dichroic dye, for example, the polyvinyl alcohol-based resin film may be immersed in an aqueous solution containing a dichroic dye. As the dichroic dye, specifically, iodine or a dichroic dye can be used.

When using iodine as a dichroic dye, it is preferable to use a method of dyeing by immersing a polyvinyl alcohol resin film in an aqueous solution containing iodine and potassium iodide. The content of iodine in the aqueous solution is preferably about 0.01 to 0.5 parts by weight per 100 parts by weight of water, and the content of potassium iodide is preferably about 0.5 to 10 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution is preferably about 20 to 40 ° C, and the time of immersion in the aqueous solution is preferably about 30 to 300 seconds.

On the other hand, when using a dichroic dye as a dichroic dye, it is preferable to employ the method of dyeing by immersing a polyvinyl alcohol-type resin film in the aqueous solution containing a water-soluble dichroic dye. The content of the dichroic dye in the aqueous solution is preferably about 1 × 10 ^-3 to 1 × 10 ^-2 parts by weight per 100 parts by weight of water. The aqueous solution may contain inorganic salts such as sodium sulfate. The temperature of the aqueous solution is preferably about 20 to 80 ° C, and the time of immersion in the aqueous solution is preferably about 30 to 300 seconds.

The boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. The content of boric acid in the boric acid aqueous solution is preferably about 2 to 15 parts by weight, more preferably about 5 to 12 parts by weight, per 100 parts by weight of water. When using iodine as a dichroic dye, it is preferable that this boric-acid aqueous solution contains potassium iodide. The content of potassium iodide in the boric acid aqueous solution is preferably about 2 to 20 parts by weight, more preferably 5 to 15 parts by weight, per 100 parts by weight of water. The immersion time in the boric acid aqueous solution is preferably about 100 to 1,200 seconds, more preferably about 150 to 600 seconds, and even more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is preferably 50 ° C or higher, and more preferably 50 to 85 ° C.

The polyvinyl alcohol-based resin film after the boric acid treatment is subjected to a water washing treatment. The water washing treatment is suitably performed, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. A polarizing plate can be obtained by performing a drying process after washing with water. The temperature of the water in the water washing treatment is preferably about 5 to 40 ° C, and the immersion time is preferably about 2 to 120 seconds. The subsequent drying process is preferably performed by using a hot-air dryer and a far-infrared heater. The drying temperature is preferably 40 to 100 ° C. The processing time in the drying process is preferably about 120 to 600 seconds.

In this way, a polarizer including a polyvinyl alcohol-based resin film in which iodine or a dichroic dye of a dichroic dye is adsorbed and aligned can be obtained.

<Protective film>

Next, as for this polarizer, the photocurable adhesive agent mentioned above was used, and the protective film was bonded to the single side or both sides. The triethyl cellulose cellulose film, which has been widely used as a protective film for polarizers, has a moisture permeability of approximately 400 g / m ² / 24hr. However, in the present invention, as a protective film attached to at least one surface of a polarizer, A resin exhibiting a lower moisture permeability than the triethyl cellulose is used, that is, a polyester resin, a polycarbonate resin, an acrylic resin, or an amorphous polyolefin-based resin.

The type of the polyester resin used for the protective film is not particularly limited, but in terms of mechanical properties, solvent resistance, abrasion resistance, and cost, polyethylene terephthalate is particularly preferred. Polyethylene terephthalate refers to a resin composed of 80% by mole or more of repeating units, and may include a structural unit derived from another copolymerization component. Examples of other copolymerization components include isophthalic acid, p-β-hydroxyethoxybenzoic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxybenzophenone, and bis (4- (Carboxyphenyl) ethane, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, and 1,4-dicarboxycyclohexane dicarboxylic acid components; such as propylene glycol, butanediol, neopentyl Diol, diethylene glycol, cyclohexanediol, ethylene oxide adducts of bisphenol A, diol components of polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These dicarboxylic acid components and diol components may be used in combination of two or more of them, if necessary. Moreover, you may use the hydroxycarboxylic acid like p-hydroxybenzoic acid together with the said dicarboxylic acid component and a diol component. As other copolymerization components, it can also be used in small amounts. A dicarboxylic acid component and / or a diol component, such as a amine bond, a urethane bond, an ether bond, and a carbonate bond, are present.

As a method for producing a polyester resin, a so-called direct polymerization method in which terephthalic acid and ethylene glycol (other dicarboxylic acids and / or other diols as necessary) are directly reacted can be employed; Any method, such as a so-called transesterification reaction method, in which a dimethyl ester of a dicarboxylic acid is subjected to a transesterification reaction with ethylene glycol (the dimethyl ester of another dicarboxylic acid and / or another diol as necessary) is further performed. Moreover, a polyester resin may contain a well-known additive as needed. Examples of the additives that can be contained include slip agents, anti-blocking agents, thermal stabilizers, antioxidants, antistatic agents, light resistance agents, and impact resistance improvers. However, since transparency is required as a protective film laminated on a polarizing film, it is preferable to limit the amount of these additives to a minimum beforehand.

The protective resin containing a stretched polyester resin can be produced by molding the raw resin into a film shape and performing uniaxial stretching or biaxial stretching treatment. By performing the stretching treatment, a film having high mechanical strength can be obtained. The method for producing the stretched polyester resin film is arbitrary and is not particularly limited, but examples thereof include a non-alignment film obtained by melting and extruding the raw material resin into a sheet shape at a temperature higher than the glass transition temperature, A method of performing transverse stretching with a tenter and then performing a heat fixing treatment.

In the case of using a polyester resin as a protective film, in order to obtain good adhesion, it is preferable to perform a corona treatment before applying the adhesive, or to use a polyester resin film having a surface that is easily adhered to the surface.

The polycarbonate resin used for the protective film is preferably made of carbonic acid and Polyesters formed from diols or bisphenols. Among these, an aromatic polycarbonate having diphenylalkane in its molecular chain is preferably used because of its excellent heat resistance, weather resistance, and acid resistance. Examples of such polycarbonates include 2,2-bis (4-hydroxyphenyl) propane (alias bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, 1,1 -Bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) isobutane, or 1,1-bis (4-hydroxyphenyl) ethane derived from bisphenols Polycarbonate.

As a method for producing a polycarbonate resin film, any method such as a casting film forming method and a melt extrusion method can be used. As an example of a specific manufacturing method, a method of dissolving a polycarbonate resin in an appropriate organic solvent to prepare a polycarbonate resin solution, casting the polycarbonate resin solution on a metal support to form a web, and the like can be cited. The web was peeled from the aforementioned metal support, and the peeled web was then dried by hot air to obtain a film.

The acrylic resin used for the protective film is not particularly limited, but is preferably a polymer containing methacrylate as a main monomer, and more preferably obtained by copolymerizing with a small amount of other comonomer components. Copolymer. It is preferable to use alkyl methacrylate as a methacrylate which is a main component of an acrylic resin, and it is particularly preferable to use methyl methacrylate. Moreover, as a comonomer component, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc. are generally used. In addition, an aromatic vinyl compound such as styrene, a vinyl cyanide compound such as acrylonitrile, or the like may be used as a comonomer component in some cases.

As a method for producing the acrylic resin, any method such as ordinary block polymerization, suspension polymerization, and emulsion polymerization can be adopted. These Among them, it is particularly preferable to adopt block polymerization in which no water-soluble component exists in the polymerization system. In addition, in order to obtain a suitable glass transition temperature or to obtain a viscosity that shows moldability for forming a suitable film, it is preferred to use a chain transfer agent during polymerization. The amount of the chain transfer agent may be appropriately determined depending on the type and composition of the monomer. Moreover, the acrylic resin may contain a well-known additive as needed. Examples of well-known additives include slip agents, anti-blocking agents, thermal stabilizers, antioxidants, antistatic agents, light stabilizers, impact resistance improvers, and surfactants. However, since transparency is required as a protective film laminated on a polarizing film, it is preferable to limit the amount of these additives to a minimum beforehand.

As a method for producing the acrylic resin film, any method such as a melt casting method, a T-die method, a melt extrusion method of a blow molding method, and a curtain method can be used. Among them, from the viewpoint of obtaining a film with good surface properties, a method is preferred in which a raw resin is melt-extruded from a T-die, for example, and at least one side of the obtained film-like material is brought into contact with a roller or a belt, Thereby, a film is formed.

The acrylic resin may contain acrylic rubber particles containing an impact modifier from the viewpoints of film-forming properties of the film and impact resistance of the film. The acrylic rubber particles referred to here are particles in which an elastic polymer mainly composed of acrylate is used as an essential component, and examples include those having a single-layer structure substantially including the elastic polymer, and For a multi-layer structure. Examples of the elastic polymer include a crosslinked elastic copolymer obtained by copolymerizing other vinyl monomers and crosslinkable monomers which are copolymerized with an alkyl acrylate as a main component. As elastic aggregation Alkyl acrylates whose main component is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc. It is particularly preferable to use an acrylate having an alkyl group having 4 or more carbon atoms. Examples of other vinyl monomers copolymerizable with the alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid such as methyl methacrylate Esters, aromatic vinyl compounds like styrene, vinyl cyanide compounds like acrylonitrile, and the like. Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, examples thereof include ethylene glycol di (meth) acrylate and The (meth) acrylic esters of polyhydric alcohols of butanediol di (meth) acrylate are the same as the alkenyl (meth) acrylic acid of allyl (meth) acrylate, divinylbenzene, and the like.

Further, a protective film may be made of a laminate of a film made of an acrylic resin not containing rubber particles and a film made of an acrylic resin containing rubber particles.

When an acrylic resin is used as the protective film, when the composition of the present invention is used, good adhesion can be obtained even without corona treatment, but it is because the coating property of the adhesive is good or the adhesion is made more For good purpose, corona treatment may be performed before applying the adhesive.

Regarding the amorphous polyolefin-based resin used for a protective film, it is usually an alicyclic polyolefin-based resin, that is, a polycyclic cyclic resin having, for example, norbornene, a derivative thereof, and dimethyl bridge The olefin-derived polymerized unit resin is preferably oriented to a ring-opened polymer with a residual double bond. Among them, a thermoplastic resin obtained by hydrogenation. The amorphous polyolefin-based resin may be a copolymer of a cyclic olefin and a chain olefin, or a polar group may be introduced. Among them, thermoplastic saturated norbornene-based resins are representative. Examples of commercially available amorphous polyolefin resins include "ARTON" by JSR Corporation, "ZEONEX" and "ZEONOR" by ZEON Corporation, "APO" and "APEL" by Mitsui Chemicals Co., Ltd., and the like. When the amorphous polyolefin resin is formed into a thin film, a known method such as a solvent casting method and a melt extrusion method can be suitably used for the film formation.

When an amorphous polyolefin-based resin is used as the protective film, in order to obtain good adhesiveness, it is preferable to perform a corona treatment before applying the adhesive.

Regarding the polarizing plate used on the visual side of the liquid crystal display device, a protective film disposed on the visual side, that is, the side opposite to the liquid crystal cell, can impart anti-glare properties. In this case, an anti-glare layer having surface unevenness is generally provided on the surface of the protective film that is the visual side, that is, the surface opposite to the side bonded to the polarizer. The anti-glare layer is generally formed by imparting irregularities to an active energy ray-curable resin by an emboss method, or by blending the active energy ray-curable resin with a refractive index different therefrom. The fine particles are hardened to impart unevenness. In the case where the protective film is made of an acrylic resin, a light-scattering layer having fine particles having a refractive index different from that of the acrylic resin serving as a binder is mixed with a light scattering layer containing an acrylic resin not containing the fine particles. It is also effective to laminate the transparent layers and constitute a protective film using the obtained laminated film. In this case, the following form can be adopted: A two-layer laminated film including the light-scattering layer and the transparent layer described above, in a form in which the light-scattering layer side is bonded to a polarizer; a three-layer structure in which both sides of the light-scattering layer are sandwiched by the transparent layer. Laminated film in the form of a transparent layer bonded to a polarizer, and the like. Furthermore, even when an acrylic resin laminated film provided with anti-glare properties by including such a light-scattering layer is used as a protective film, the surface to be the visual side thereof, that is, the surface opposite to the surface to be bonded to the polarizer is used. It is also effective to provide an anti-glare layer on the side surface to further improve the anti-glare performance.

As described above, particularly when an acrylic resin film is used as a protective film, the adhesiveness of an epoxy resin monomer that does not contain an aromatic ring as shown in the aforementioned Patent Document 6 (Japanese Patent Application Laid-Open No. 2004-245925) is not necessarily required. It is sufficient that the composition of the present invention produces good adhesion even when the acrylic resin film is used as a protective film. Therefore, this invention is especially useful when an acrylic resin film is used as a protective film.

In the present invention, a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin based on the above-mentioned photocurable adhesive are bonded to at least one surface of the polarizer with a photocurable adhesive as described above. Protective film of transparent resin film selected from resin. Only when the protective film is laminated on one side of the polarizer, for example, a form in which an adhesive layer or the like for directly adhering to another member such as a liquid crystal cell is directly provided on the other side of the polarizer may be adopted.

On the other hand, when a protective film is bonded to both surfaces of a polarizer, each protective film may be the same kind of protective film, or may be a different kind of protective film. Specifically, for example, the following form can be adopted : A form in which a polyester resin film is bonded on both sides of a polarizer as a protective film; a form in which a polycarbonate resin is bonded on both sides of a polarizer as a protective film; and a form in which an acrylic resin is bonded on both sides of a polarizer as a protective film ; The form of laminating amorphous polyolefin resin as a protective film on both sides of the polarizer; laminating polyester resin, polycarbonate resin, acrylic resin, and amorphous polyolefin resin on one side of the polarizer Any of the transparent resin films selected from the above is used as a protective film, and any one selected from polyester resins, polycarbonate resins, acrylic resins, and amorphous polyolefin-based resins is bonded to the other side of the polarizer. The form of the transparent resin film different from the above-mentioned one-sided protective film as the protective film. Further, a transparent resin film selected from polyester resin, polycarbonate resin, acrylic resin, and amorphous polyolefin resin can be laminated on one side of the polarizer as a protective film, and On the other hand, a transparent resin film different from any one selected from polyester resins, polycarbonate resins, acrylic resins, and amorphous polyolefin-based resins is laminated as a protective film. When the protective film is bonded to both sides of the polarizer, the two protective films may be bonded one by one on one side in stages, or the two sides may be bonded on one stage.

When a protective film is bonded to both sides of a polarizer, one of these is a resin film different from polyester resin, polycarbonate resin, acrylic resin, and amorphous polyolefin resin. In this case, as a preferable example of this other resin, a cellulose resin is mentioned. In addition, the protective film including a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin-based resin bonded to one surface of the polarizer is according to the present invention. The hardening adhesive is adhered, but the protective film attached to the other surface of the polarizer may be adhered by another adhesive. For example, when a protective film such as a resin film having a relatively high moisture permeability is provided on one surface of the polarizer, polyvinyl alcohol may be used on the bonding surface of the resin film having a high moisture permeability. Adhesives other than epoxy, such as adhesives. However, the photocurable adhesive of the present invention generates high adhesion even to the cellulose-based resin film exemplified here. Therefore, the same adhesive is used on both sides of the polarizer because the operation is simplified and advantageous. .

The cellulose-based resin that can be used as one of the protective films is a partially or fully esterified cellulose, and examples thereof include cellulose acetate, propionate, butyrate, and mixed esters thereof. Specific examples include triethyl cellulose, diethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like. Examples of commercially available films containing such cellulose ester resins include "Fujitac TD80", "Fujitac TD80UF" and "Fujitac TD80UZ" manufactured by Fujifilm Corporation, manufactured by Konica Minolta Opto Co., Ltd. "KC8UX2M" and "KC8UY". Alternatively, a cellulose-based resin film provided with an optical compensation function may be used. Examples of the optical compensation film include a film containing a compound having a retardation adjusting function in a cellulose-based resin, a coating of a compound having a retardation adjusting function on a surface of the cellulose-based resin film, and a cellulose-based resin. Film obtained by uniaxially or biaxially stretching a film. Examples of commercially available cellulose-based optical compensation films include "Wide View Film WV BZ 438" and " Wide View Film WV EA "," KC4FR-1 "and" KC4HR-1 "made by Konica Minolta Opto Co., Ltd., etc.

Examples of other resins different from polyester resins, polycarbonate resins, acrylic resins, and amorphous polyolefin-based resins and transparent resins having low moisture permeability that can be used as the other protective film include polyfluorinated resins. , Alicyclic polyfluorene imine resin, etc.

Regarding the protective film, prior to laminating to the polarizer, the laminating surface may be subjected to easy adhesion treatment such as saponification treatment, corona treatment, primer treatment, and anchor coating treatment. In addition, the protective film may be provided with various treatment layers such as a hard coat layer, an anti-reflection layer, and an anti-glare layer on the surface on the opposite side of the bonding surface to which the polarizer is bonded. The thickness of the protective film is preferably in the range of about 5 to 200 μm, more preferably 10 to 120 μm, and even more preferably 10 to 85 μm.

[Manufacturing method of polarizing plate]

The polarizing plate of the present invention can be produced by a method including the following steps: an adhesive coating step, the polarizer described above, and a resin including a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin-based resin. At least one of the bonding surfaces of the protective film of the selected transparent resin film is coated with the photocurable adhesive described above; the bonding step includes bonding the polarizer through the obtained adhesive layer. And a protective film; in a curing step, the photocurable adhesive is cured in a state where the polarizer and the protective film are bonded together via the adhesive layer.

<Adhesive coating step>

In the adhesive application step, the photocurable adhesive described above is applied to at least one of the adhesive surfaces of the polarizer and the protective film. Apply photocuring directly on the surface of the polarizer or protective film In the case of an agent, the coating method is not particularly limited. For example, various coating methods such as doctor blades, wire rods, die coaters, comma coaters, and gravure coaters can be used. Alternatively, a method may be used in which a photo-curing adhesive as described above is cast between a polarizer and a protective film, and then pressed with a roller or the like to uniformly press and spread.

The ambient temperature of the adhesive coating step is preferably 15 to 30 ° C, and particularly preferably 20 to 25 ° C. In addition, the relative humidity of the coating environment is preferably 90% or less, more preferably 80% or less, and still more preferably 30 to 80%. By adjusting the ambient temperature and humidity in the adhesive coating step to the above-mentioned ranges, the hardenability and the adhesive force can be made good.

<Laminating step>

After the photocurable adhesive is applied in this manner, it is supplied to the bonding step. In this bonding step, for example, when a photocurable adhesive is applied to the surface of the polarizer by the previous coating step, a protective film is laminated thereon; and the surface of the protective film is applied by the previous coating step. In the case of a photocurable adhesive, a polarizer is laminated thereon. When a photocurable adhesive is cast between the polarizer and the protective film, the polarizer and the protective film are laminated in this state. When a protective film is bonded to both surfaces of a polarizer, and when the photocurable adhesive of this invention is used on both surfaces, a photocurable adhesive is laminated | stacked on both surfaces of a polarizer, respectively. Protective film. Moreover, in this state, it usually becomes the polarizer side and the protective film side when the protective film is laminated on one side of the polarizer, and when the protective film is laminated on both sides of the polarizer in this state. Both sides of the protective film side) are sandwiched by a roller or the like and pressurized. Here, the material of the roller can be metal, rubber, or the like. The rollers arranged on both sides can be phased The same material can also be different materials.

<Hardening step>

An object in a state where the polarizer and the protective film are bonded together via the uncured photocurable adhesive as described above is then supplied to the curing step. In this hardening step, the photocurable adhesive is irradiated with active energy rays to harden an adhesive layer containing an epoxy compound, a (meth) acrylate, an oxetane compound, and the like, so that the polarizer and The protective film is then attached. When a protective film is bonded to one surface of a polarizer, an active energy ray can be irradiated from either a polarizer side or a protective film side. When a protective film is attached to both sides of the polarizer, the active energy rays are irradiated from either side of the protective film in a state where the protective film is attached to both sides of the polarizer through a photocurable adhesive. It is advantageous to harden both sides of the photocurable adhesive at the same time. However, when any one of the protective films is incorporated with an ultraviolet absorber (for example, when the cellulose-based resin film to which the ultraviolet absorber is incorporated is one of the protective films), the active energy ray is ultraviolet. In the case of ultraviolet rays, the ultraviolet rays are usually irradiated from the side of another protective film which is not doped with an ultraviolet absorber.

As the active energy ray, visible light, ultraviolet rays, X-rays, electron beams, and the like can be used. Generally, ultraviolet rays are preferably used because they are easy to handle and have a sufficient curing rate. The light source of the active energy ray is not particularly limited, and those with a light emission distribution below 400 nm can be used, for example, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, chemical lamp, black light lamp, microwave-excited mercury lamp , Metal halide lamps (metal halide lamps), LED lights, etc.

The light irradiation intensity of the photocurable adhesive is determined for each target composition and is not particularly limited. However, the irradiation intensity in the wavelength range effective for activation of the polymerization initiator is preferably It is set so that UV-B (medium-wavelength region ultraviolet of 280 to 320 nm) becomes 1 to 3,000 mW / cm ² . When the irradiation intensity is in the above range, the reaction time is moderate, and the yellowing of the photocurable adhesive and the polarizer caused by the heat radiated from the lamp and the heat generated during the polymerization of the photocurable adhesive can be suppressed. Degradation.

Regarding the light irradiation time of the photo-curable adhesive, it is controlled for each hardened composition and is not particularly limited, but the cumulative light amount expressed by the product of the irradiation intensity and the irradiation time is preferably UV-B. The language is set to 10 ~ 5,000mJ / cm ² . When the total amount of light is within the above range, active species derived from the polymerization initiator are sufficiently generated, the adhesive layer is sufficiently hardened, and the irradiation time is short, and the productivity is excellent.

When the photo-curable adhesive is hardened by irradiating active energy rays, it is preferred that the functions of the polarizing plate such as the polarization degree, transmittance and color phase of the polarizer, and the transparency of the protective film are not reduced. Harden under conditions.

In the polarizing plate thus obtained, the thickness of the adhesive layer is preferably 50 μm or less, more preferably 20 μm or less, even more preferably 10 μm or less, and particularly preferably 5 μm or less.

As a preferred method for increasing the adhesion between the adhesive and the protective film of the present invention, after the polarizer and the protective film are bonded using the adhesive, before the active energy rays are irradiated, the optical properties of the polarizer may not be damaged. A heating step is added within the range of characteristics. As this time plus The thermal conditions are preferably within a range in which no shrinkage of the polarizer or deterioration of optical characteristics occurs. Suitable heating conditions vary depending on the molecular weight of the acrylic resin and the like, but examples include 60 ° C for 1 to 10 seconds, and 40 ° C for 5 to 30 seconds. After heating, until the active energy ray is irradiated, even if the temperature of the adhesive is cooled to 40 ° C or lower, the effect of improving the adhesive force is not impaired.

In addition, as another preferable method for improving the adhesive force between the adhesive and the protective film of the present invention, the following method can be cited: the polarizer and the protective film are bonded together without heating, that is, even at 20 to 25 ° C. The length of the production line after the film is irradiated with the active energy ray is increased, so that the time after the adhesive is brought into contact with the acrylic resin is extended to about 60 seconds.

However, the adhesive of the present invention has the advantage that even if the time after the adhesive is in contact with the acrylic resin protective film is about 20 to 25 ° C. for about 20 to 30 seconds, a good adhesive strength is exhibited.

[Optical member]

When a polarizing plate is used, it may be an optical member in which an optical layer showing an optical function other than a polarizing function is laminated on one side. Optical layers laminated on a polarizing plate for the purpose of forming an optical member include, for example, a reflective layer, a transflective reflective layer, a light scattering layer, a retardation plate, a light collecting plate, and a brightness-improving film for forming a liquid crystal display device. Of various optical layers. The aforementioned reflective layer, semi-transmissive reflective layer, and light-scattering layer are used in the case of forming an optical member including a reflective type or a semi-transmissive type, a scattering type, or a dual-purpose type of polarizing plate.

Reflective polarizers are used to visually A liquid crystal display device of a type that displays incident light on the side and displays it can omit a light source such as a backlight, and thus it is easy to reduce the thickness of the liquid crystal display device. In addition, the transflective polarizer is a type of liquid crystal display device that is used to display a reflective display in a bright place and a light source such as a backlight in a dark place. An optical member as a reflective polarizing plate is, for example, a foil or a vapor-deposited film containing a metal such as aluminum is attached to a protective film on a polarizer, so that a reflective layer can be formed. Regarding the optical member that is a transflective polarizing plate, the aforementioned reflective layer may be a half mirror, or a reflecting plate containing pearl pigment or the like may be used to display a light transmitting plate followed by polarized light. Plate, thus forming. On the other hand, as an optical member as a scattering-type polarizing plate, for example, a method of applying a matte treatment to a protective film on a polarizing plate, a method of applying a resin containing fine particles, and a thin film containing fine particles are used. And other methods to form a fine uneven structure on the surface.

The formation of the optical member as a polarizing plate for both reflection and scattering can be performed by, for example, providing a reflective layer reflecting the uneven structure on the fine uneven structure surface of the scattering-type polarizing plate. The reflective layer having a fine uneven structure has the advantages of scattering incident light by diffuse reflection, preventing directivity and flicker, and suppressing unevenness in brightness and darkness. In addition, with respect to the resin layer and film containing fine particles, incident light and reflected light are scattered when transmitting through the layer containing fine particles, and thus have advantages such that unevenness in light and darkness can be further suppressed. The reflective layer reflecting the fine uneven structure on the surface can be formed by directly attaching a metal to the surface of the fine uneven structure by using a method such as vacuum evaporation, ion plating, sputtering, and other methods such as evaporation and plating. As to form a table The fine particles mixed with a fine uneven structure on the surface can be, for example, inorganic fine particles including silicon dioxide, aluminum oxide, titanium oxide, zirconia, tin oxide, indium oxide, and the like having an average particle diameter of 0.1 to 30 μm. Crosslinked polymers and other organic fine particles.

On the other hand, the retardation plate as the optical layer is used for the purpose of compensating the retardation of the liquid crystal cell and the like. Examples thereof include birefringent films including stretch films of various plastics, films in which discotic liquid crystals and nematic liquid crystals are aligned and fixed, and the above-mentioned liquid crystal layer is formed on a film substrate. In this case, as a film substrate that supports the alignment liquid crystal layer, a cellulose-based film such as triethylammonium cellulose is preferably used.

Examples of the plastic that forms a birefringent film include polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, polypropylene, polyarylate, polyamine, Amorphous polyolefin resin and the like. The stretched film may be a stretched film processed in a suitable manner such as uniaxial or biaxial. In addition, it may be a birefringent film in which the refractive index in the thickness direction of the film is controlled by applying a shrinkage force and / or a stretching force to the heat shrinkable film. The retardation plate may be used in combination of two or more plates for the purpose of controlling optical characteristics such as widening.

The light collecting plate is a plate used for the purpose of light path control and the like, and can be formed as a cymbal array sheet, a lens array sheet, or a dot attachment sheet.

The brightness-improving film is a film used for the purpose of improving the brightness in a liquid crystal display device and the like, and as examples thereof, the following are listed: Reflective linear polarized light separation sheet designed by laminating multiple films with mutually different refractive index anisotropy to produce anisotropy in reflectance; a cholesteric liquid crystal polymer Alignment film, a circularly polarized light separation sheet obtained by supporting an alignment liquid crystal layer on a film substrate.

As for the optical member, one or two or more layers can be selected from a polarizing plate and a reflective layer, a transflective reflective layer, a light scattering layer, a retardation plate, a light collecting plate, a brightness enhancement film, and the like depending on the purpose of use. The optical layers are combined to form a laminate of two or more layers. In this case, two or more optical layers, such as a light-scattering layer, a retardation plate, a light-condensing plate, and a brightness-improving film, may be arranged. The arrangement of each optical layer is not particularly limited.

Various optical layers forming the optical member are integrated with the polarizing plate by using an adhesive. However, the adhesive used for this purpose is not particularly limited as long as it is an adhesive that forms the adhesive layer well. From the viewpoints of simplicity of the publishing industry and prevention of optical distortion, an adhesive (also referred to as a pressure-sensitive adhesive) is preferably used. As the adhesive, an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyether, or the like can be used as a matrix polymer. Among them, it is preferable to select, for example, an acrylic adhesive, which is excellent in optical transparency, maintains moderate wettability, cohesive force, and adhesion to a substrate, and further has weather resistance, heat resistance, and the like. 2. Use an adhesive that does not cause peeling or peeling problems under humidified conditions. As for the acrylic adhesive, an alkyl ester of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as methyl, ethyl, or butyl, and (meth) Functional group-containing acrylic monomers including acrylic acid, hydroxyethyl (meth) acrylate, and the like are polymerized by blending such that the glass transition temperature is preferably 25 ° C. or lower, and more preferably 0 ° C. or lower. An acrylic copolymer having a weight average molecular weight of 100,000 or more obtained by polymerization can be used as a base polymer.

The formation of the adhesive layer to the polarizing plate can be performed, for example, by dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a liquid having a solid concentration of 10 to 40% by weight. It is a method of directly coating the polarizing plate to form an adhesive layer; a method of forming an adhesive layer on the isolation film in advance, and transferring it to the polarizing plate to form an adhesive layer. The thickness of the adhesive layer is determined depending on its adhesion, etc., but a range of about 1 to 50 μm is appropriate.

In addition, the adhesive layer may be blended as necessary: fillers containing glass fibers, glass beads, resin beads, metal powder, other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, and the like. As for the ultraviolet absorber, there are a salicylate-based compound, a benzophenone-based compound, a benzotriazole-based compound, a cyanoacrylate-based compound, a nickel complex salt-based compound, and the like.

[Liquid crystal display device]

By disposing the above-mentioned optical member on one or both sides of the liquid crystal cell, a liquid crystal display device can be manufactured. The liquid crystal cell used is arbitrary, and for example, a liquid crystal display device can be formed by using various liquid crystal cells such as an active matrix driving type represented by a thin film transistor type and a simple matrix driving type represented by a super twisted nematic type. The optical components provided on both sides of the liquid crystal cell may be the same optical component or different lights. 学 Widget.

[Example]

Hereinafter, the present invention will be described in more detail by showing examples and comparative examples, but the present invention is not limited to these examples. In the example,% indicating the usage amount to the content ratio is a weight basis unless otherwise specified. In addition,% of humidity indicates a relative humidity at 23 ° C. In addition, "part" means "weight part" unless there is particular notice in advance.

In Examples and Comparative Examples, the components used in the preparation of the photocurable adhesive composition are shown below, and are hereinafter represented by the compound name or each symbol (trade name itself or a part thereof).

(A) Component: Poly (meth) acrylate compound

HDDA: 1,6-hexanediol diacrylate, "Light Acrylate 1,6HX-A" manufactured by Kyoeisha Chemical Co., Ltd.

DCPA: Dimethylol tricyclodecane diacrylate, "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd.

(B) Ingredient: Polyglycidyl ether compound

HDDGE: 1,6-hexanediol diglycidyl ether, distilled refined product, total chlorine content 0.08%.

(C) Component: Oxycyclobutane compound

OXT221: bis [(3-ethyloxycyclobutane-3-yl) methyl] ether, "Aron Oxetane OXT-221" manufactured by Toa Kosei Co., Ltd.

(D) component: The polymer which has an epoxy group

Polymer D1: A polymer obtained in Production Example 1 described later.

Polymer D2: A polymer obtained in Production Example 2 described later.

(E) Component: Photocationic polymerization initiator

CPI110P: Triarylphosphonium hexafluorophosphate (100% active ingredient), "CPI-110P" manufactured by San-Apro Ltd.

(F) Ingredient: Photo radical polymerization initiator

Irg184: 1-hydroxy-cyclohexyl-phenyl-one, "Irgacure 184" manufactured by BASF Corporation.

(G) Ingredient: Leveling agent

SH28: Toray. "DOW CORNING TORAY SH 28 PAINT ADDITIVE", a silicone leveling agent made by Dow Corning.

(B) 'component: epoxy compound other than (B) component

JER828: Bisphenol A epoxy resin, "jER-828US" manufactured by Mitsubishi Chemical Corporation.

(D) 'component: Polymer other than (D) component

BR87: a polymer of methyl methacrylate (Mw 25,000, acid value 10.5 mgKOH / g) having no epoxy group, and "DIANAL BR-87" manufactured by Mitsubishi Rayon Corporation.

LA2250: a block copolymer (Mw80,000) of butyl acrylate and methyl methacrylate without epoxy groups, "Clarity LA2250" manufactured by Kuraray Co., Ltd.

Polymer D'1: A polymer obtained in Production Example 3 described later.

Polymer D'2: The polymer obtained in Production Example 4 described later.

Polymer D'3: A polymer obtained in Production Example 5 described later.

[Manufacturing example 1]

The jacket temperature of a 1000-mL pressure stirred tank reactor equipped with an oil jacket was maintained at 190 ° C.

Next, while keeping the pressure of the reactor constant, methyl methacrylate (hereinafter, referred to as "MMA") (45 parts), glycidyl methacrylate (hereinafter, referred to as "GMA") ( 30 parts), styrene (hereinafter, referred to as "St") (25 parts), methyl ethyl ketone (hereinafter, referred to as "MEK") (18 parts) as a polymerization solvent, and tertiary butyl peroxide as a polymerization initiator Oxide (hereinafter, referred to as "DBP") (0.25 parts) monomer mixture was continuously supplied from the raw material tank to the reactor at a constant supply rate (48 g / min, residence time: 12 minutes), and The reaction liquid having a sufficient supply amount of the bulk mixture is continuously drawn from the outlet. Immediately after the start of the reaction, the reaction temperature was temporarily lowered, and it was confirmed that the temperature was increased due to the heat of polymerization. However, by controlling the temperature of the oil jacket, the internal temperature of the reactor was maintained at 192 to 194 ° C.

The time point after the internal temperature of the reactor stabilized 36 minutes was set as the starting point for taking the reaction liquid, and the reaction was continued for 25 minutes thereafter. As a result, 1.2 kg of the monomer mixed liquid was supplied and 1.2 kg of the reaction liquid was recovered.

Thereafter, the reaction solution was introduced into a thin-film evaporator to separate volatile components such as unreacted monomers, thereby removing volatile components such as unreacted monomers, to obtain a polymer "Polymer D1".

GPC was measured for the obtained polymer D1. As a result, the polystyrene-equivalent number average molecular weight (hereinafter, referred to as "Mn") was 3,500, Mw (weight average molecular weight) was 9,900, and Tg (DSC measurement, heating rate 10 ° C / minute) ) Is 65 ° C.

[Manufacturing example 2]

The jacket temperature of the same reactor as in Production Example 1 was maintained at 180 ° C.

Next, while keeping the pressure of the reactor constant, A monomer mixture containing MMA (60 parts), GMA (30 parts), methyl acrylate (10 parts), MEK (18 parts) as a polymerization solvent, and DBP (0.25 parts) as a polymerization initiator. The same constant supply rate as in Example 1 was continuously supplied from the raw material tank to the reactor, and the reaction liquid corresponding to the supply amount of the monomer mixture was continuously extracted from the outlet. Immediately after the start of the reaction, the reaction temperature was temporarily lowered, and it was confirmed that the temperature was increased due to the heat of polymerization. However, by controlling the temperature of the oil jacket, the internal temperature of the reactor was maintained at 182 to 184 ° C.

The time point after the internal temperature of the reactor stabilized 36 minutes was set as the starting point for taking the reaction liquid, and the reaction was continued for 25 minutes thereafter. As a result, 1.2 kg of the monomer mixed liquid was supplied and 1.2 kg of the reaction liquid was recovered.

Thereafter, the reaction solution was introduced into a thin-film evaporator, and volatile components such as unreacted monomers were separated to remove volatile components such as unreacted monomers, thereby obtaining a polymer "Polymer D2".

The obtained polymer D2 was evaluated by the same method as in Production Example 1. As a result, Mn was 3,200, Mw was 8,500, and Tg was 53 ° C.

[Comparative Manufacturing Example 1]

The jacket temperature of the same reactor as in Production Example 1 was maintained at 181 ° C.

Next, while keeping the pressure of the reactor constant, butyl acrylate (hereinafter, referred to as "BA") (45 parts), 2-ethylhexyl acrylate (45 parts), MMA (10 parts), A monomer mixture of isopropanol (9 parts), MEK (9 parts) as a polymerization solvent, and DBP (0.25 parts) as a polymerization initiator was continuously supplied from a raw material tank at a constant supply rate as in Production Example 1. In the reactor, a reaction liquid corresponding to the supply amount of the monomer mixture was continuously extracted from the outlet. Immediately after the reaction, the reaction temperature The temperature was temporarily lowered, and it was confirmed that the temperature was increased due to the heat of polymerization. However, by controlling the temperature of the oil jacket, the internal temperature of the reactor was maintained at 183 to 185 ° C.

The time point after the internal temperature of the reactor stabilized 36 minutes was set as the starting point for taking the reaction liquid, and the reaction was continued for 25 minutes thereafter. As a result, 1.2 kg of the monomer mixed liquid was supplied and 1.2 kg of the reaction liquid was recovered. Thereafter, the reaction solution was introduced into a thin-film evaporator to separate volatile components such as unreacted monomers, thereby removing volatile components such as unreacted monomers, to obtain a polymer "Polymer D'1".

The obtained polymer D'1 was evaluated by the same method as in Production Example 1. As a result, Mn was 2,500, Mw was 7,500, Tg was -55 ° C, and viscosity was 20,000 mPa at 25 ° C. s.

[Comparative Manufacturing Example 2]

The jacket temperature of the same reactor as in Production Example 1 was maintained at 187 ° C.

Next, while keeping the pressure of the reactor constant, a monomer including BA (50 parts), GMA (50 parts), MEK (18 parts) as a polymerization solvent, and DBP (0.25 parts) as a polymerization initiator was charged. The mixture was continuously supplied to the reactor from the raw material tank at a constant supply rate similar to that in Production Example 1, and the reaction solution corresponding to the supply amount of the monomer mixture was continuously extracted from the outlet. Immediately after the start of the reaction, the reaction temperature was temporarily lowered, and it was confirmed that the temperature was increased due to the heat of polymerization. However, by controlling the temperature of the oil jacket, the internal temperature of the reactor was maintained at 189 to 191 ° C.

The time point after the internal temperature of the reactor stabilized 36 minutes was set as the starting point for taking the reaction liquid, and the reaction was continued for 25 minutes thereafter. As a result, 1.2 kg of the monomer mixed liquid was supplied and 1.2 kg of the reaction liquid was recovered.

Thereafter, the reaction solution was introduced into a thin-film evaporator, and volatile components such as unreacted monomers were separated to remove volatile components such as unreacted monomers, thereby obtaining a polymer "Polymer D'2".

The obtained polymer D'2 was evaluated by the same method as in Production Example 1. As a result, Mn was 3,460, Mw was 9,700, Tg was -10 ° C, and viscosity was 12,200 mPa at 80 ° C. s.

[Comparative Manufacturing Example 3]

The jacket temperature of the same reactor as in Production Example 1 was maintained at 180 ° C.

Next, while keeping the reactor pressure constant, a monomer containing St (70 parts), GMA (30 parts), MEK (18 parts) as a polymerization solvent, and DBP (0.25 parts) as a polymerization initiator was charged. The mixture was continuously supplied to the reactor from the raw material tank at a constant supply rate similar to that in Production Example 1, and the reaction solution corresponding to the supply amount of the monomer mixture was continuously extracted from the outlet. Immediately after the start of the reaction, the reaction temperature was temporarily lowered, and it was confirmed that the temperature was increased due to the heat of polymerization. However, by controlling the temperature of the oil jacket, the internal temperature of the reactor was maintained at 182 to 184 ° C.

The time point after the internal temperature of the reactor stabilized 36 minutes was set as the starting point for taking the reaction liquid, and the reaction was continued for 25 minutes thereafter. As a result, 1.2 kg of the monomer mixed liquid was supplied and 1.2 kg of the reaction liquid was recovered.

Thereafter, the reaction solution was introduced into a thin-film evaporator to separate volatile components such as unreacted monomers, thereby removing volatile components such as unreacted monomers, to obtain a polymer "Polymer D'3".

The obtained polymer D'3 was evaluated by the same method as in Production Example 1. As a result, Mn was 3,700, Mw was 11,000, and Tg was 65 ° C.

○ Example 1 to Example 8, Comparative Example 1 to Comparative Example 8

[Preparation of Photocurable Adhesive Composition]

The respective components shown in Tables 1 to 4 were blended at respective ratios, and stirred and mixed according to a conventional method to prepare a photocurable adhesive composition.

The viscosity of the obtained composition at 25 ° C. was measured using an E-type viscometer manufactured by Toki Sangyo Co., Ltd.

[Production of polarizing plate]

Here, the following two films are used as the protective film.

Stretched norbornene-based resin film: 70 μm thick, trade name “ZEONOR film”, manufactured by ZEON Corporation. This film is subjected to a corona discharge treatment, and is then supplied to a lamination with a polarizer.

Acrylic resin film: 80 μm thick, trade name "Technolloy S001", manufactured by Sumitomo Chemical Co., Ltd. This film was also subjected to a corona discharge treatment, and was then supplied to a lamination with a polarizer.

On the corona discharge-treated surface of the stretched norbornene-based resin film, the composition prepared above was coated with a bar coater to a thickness of 3 μm. This coated surface was bonded to a polarizer having iodine adsorbed and aligned with polyvinyl alcohol using a hand roller.

Next, on the corona discharge-treated surface of the acrylic resin film, the composition prepared as described above was applied with a bar coater to a thickness of 3 μm. Thereafter, a polarizing plate integrated with the norbornene-based resin film using a liquid composition was bonded to the coating surface of the acrylic resin film using a manual pressure roller.

For polarizers in which a protective film is bonded to both sides in this manner, an ultraviolet irradiation device with a belt conveyer (a high-pressure mercury lamp manufactured by EYE Graphics, Co., Ltd. is used for the lamp), and a norbornene-based resin is used. The surface of the film was irradiated with ultraviolet rays at a cumulative light amount of 250 mJ / cm ² (UV-B) to harden the adhesive composition.

The experiment was performed under the conditions of 23 ° C and 80% relative humidity.

In addition, after the adhesive composition is applied to the acrylic resin film, the time until the irradiation with ultraviolet rays is unified into a range of 20 to 25 seconds.

[Evaluation test]

About the polarizing plate after ultraviolet irradiation, the following methods were used to evaluate the hardenability, the blade insertion adhesion force, the bending and peeling adhesion force of polarizers at room temperature (before the moist heat resistance test), the moist heat resistance test, and the polarized light after the moist heat resistance test. The bending and peeling adhesion force of the sheet and the cold-heat cycle test are shown in Tables 1 to 4.

<Hardenability>

Fifteen seconds after the ultraviolet light was irradiated, the acrylic resin film and the polarizer were peeled off by hand, and according to the degree of hardening at this time, it was judged according to the following three levels.

(Circle): It is not liquid, and bubble does not generate | occur | produce in the film conveyance process during manufacture.

Δ: Half is liquid, and bubbles may be generated during the film transport step during production.

×: It is liquid, and air bubbles are generated in the film transporting step during production.

<Cutting blade insertion force>

Insert the blade of a cutter knife obliquely from the top of the acrylic resin film to polarized light that has passed for more than 2 days after the irradiation of ultraviolet rays The board is judged according to the situation at this time and the resistance according to the following four levels.

：: The blade does not enter, or the resistance is quite strong even when the blade enters, and the acrylic resin film immediately breaks.

○: The blade enters but the resistance is strong. When the peeling is intended to be expanded, the acrylic resin film is broken.

(Triangle | delta): Resistance is felt even if a blade enters, but peeling can be enlarged.

×: The blade enters, the resistance is very weak, and it is the extent that the blade travels with a little force at the interface.

<Flexible peeling adhesion force of polarizers at room temperature (before humidity and heat test)>

A polarizing plate having a width of 1 inch and a length of 15 cm was cut out after irradiating ultraviolet rays for more than 2 days, and an acrylic resin film side was attached to a glass plate using an adhesive tape. Next, the polarizer film on the upper side of the norbornene-based resin film was peeled off, a 180 ° peel test was performed at a tensile speed of 300 mm / minute, and the adhesive force (N / inch) is described in the table.

<Damp and heat resistance test>

The polarizing plate was cut into a width of 4 cm and a length of 6 cm after 2 days or more after being irradiated with ultraviolet rays, and left in a high-temperature and high-humidity environment at 60 ° C. and a relative humidity of 90% for 500 hours. The polarizing plate after the moisture and heat resistance test was judged by visual observation of peeling and discoloration according to the following three levels.

○: No peeling or discoloration was observed.

△: Slight peeling and discoloration were confirmed.

×: Peeling and discoloration were confirmed.

<Bending and Peel Adhesion of Polarizer After Moisture Resistance Test>

A polarizing plate having a width of 1 inch and a length of 15 cm was cut out after irradiating ultraviolet rays for more than 2 days, and an acrylic resin film side was attached to a glass plate using an adhesive tape. This was left in a high-temperature, high-humidity environment at 60 ° C and a relative humidity of 90% for 500 hours, and then taken out in an environment of 23 ° C and a relative humidity of 50%, and the adhesive force after 5 minutes after the removal was measured. The measurement was performed by peeling the polarizer film on the upper side of the norbornene-based resin film and peeling it at 180 ° at a stretching speed of 300 mm / min. The results (N / inch) are described in the table.

<Cold and hot cycle test>

The polarizing plate that had been irradiated with ultraviolet rays for more than 2 days was left at -35 ° C for 60 minutes, and then at + 70 ° C for 60 minutes. This cycle was repeated 300 times in a cold-heat shock cycle test. The polarizing plate after the cold-heat cycle test was visually observed and judged according to the following three levels.

○: No external appearance was confirmed.

(Triangle | delta): Slight appearance defect was confirmed.

×: The appearance was confirmed to be defective.

The unit of each numerical value of the formula composition in Tables 1 to 4 is% by weight.

Although this example is implemented under high humidity conditions (23 ° C and 80%) which are not conducive to cation hardening, the compositions of Examples 1 to 8 have properties of viscosity, hardenability, blade insertion adhesion, The results of the polarizing plate bending and peeling adhesion force, the moist heat resistance test, the polarizing plate bending and peeling adhesion force after the moist heat resistance test, and the cold-heat cycle test were all good.

Regarding Example 2 in which the blending amount of the polymer D1 was 10%, compared with Example 1 in which the blending amount of the polymer D1 was 4%, both the cutting force and the peeling force were excellent. In addition, Example 2 in which polymer D1 and polymer D'1 [a polymer containing no monomer (d1) and having a Tg lower than the lower limit of the (D) component] were used in combination, and implementation without polymer D'1 In comparison with Example 3, both the blade adhesion force and the peel adhesion force were excellent.

In Example 4 in which the (A) component of Example 3 was slightly reduced and the (B) and (C) components were slightly increased, the peeling adhesion was more excellent. In addition, in Example 5 in which HDDA and DCPA were used as the component (A), both the blade insertion force and the peeling force were particularly excellent.

In Example 6 in which the polymer D1 of Example 2 was changed to the polymer D2, it was also low viscosity, hardenability, blade insertion adhesion force, bending peeling adhesion force of polarizers at room temperature storage products, moist heat resistance test, and moist heat resistance. The polarizing plate after the test was excellent in both the peeling adhesion force and the results of the cold-heat cycle test.

On the other hand, regarding Comparative Example 1 in which the polymer D1 of Example 1 was changed to BR87 [a polymer having no epoxy group], and the polymer D1 of Example 2 was changed to a polymer D'2 [does not include a monomer Body (d2), polymer having a Tg less than the lower limit of the (D) component], Comparative Example 2, the blade insertion adhesion force, and the peel adhesion force before and after the moist heat resistance test were insufficient. Further, in Comparative Example 3 in which the polymer D1 of Example 2 was changed to the polymer D'3 [a polymer not containing the monomer (d2)], the adhesion after the moist heat resistance test was insufficient.

In Comparative Example 4, which did not contain the component (A), the sclerosis was poor. In Comparative Example 5 in which the component (A) was excessively contained, the blade insertion force was poor.

Comparative Example 6 not containing the component (B) was defective in all the items, and Comparative Example 7 not including the component (B) excessively was also defective in almost all the items.

In Comparative Example 8 which contained the component (C) excessively, the peeling adhesive force was good, but the adhesive force by the blade insertion method was insufficient.

[Industrial availability]

The photocurable adhesive composition of the present invention has a low viscosity and Easy to apply into a thin film, even when applied under high humidity and light curing, it has excellent hardenability and adhesion, excellent adhesion after the end of the moist-heat resistance test, and the polarizer obtained is also excellent in durability, so it can be used better For manufacturing polarizing plates.

Claims (16)

A photocurable adhesive composition is a group consisting of a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin resin on a polarizer containing a polyvinyl alcohol resin film. The adhesive composition of the protective film of the transparent resin film selected in the group is characterized in that the content ratio of the following components (A) to (E) in the composition is (A) component: 5 to 50% by weight, (B ) Ingredients: 5 to 45% by weight, (C) Ingredients: 5 to 45% by weight, (D) Ingredients: 1 to 25% by weight, (E) Ingredients: 0.5 to 10% by weight, (A) The number of carbon atoms is 2 Poly (meth) acrylate of a polyhydric alcohol of ~ 15, (B) a polyglycidyl ether of a polyalcohol having 2 to 10 carbon atoms, and (C) having more than two oxocycloalkyl groups in one molecule A compound having a molecular weight of 500 or less, (D) a polymer containing (d1) a compound having an epoxy group and an ethylenically unsaturated group, (d2) a hydrocarbon group having 1 to 10 carbon atoms, and a methyl group Acryl fluorenyl compound and (d3) a compound having one ethylenically unsaturated group as constituent monomer units, and these monomers are polymerized at high temperature The polymer produced has a glass transition temperature of 20 ° C or higher and a weight average molecular weight of 1,000 to 30,000, but (d3) excludes (d1) and (d2) and (E) a photocationic polymerization initiator. The photocurable adhesive composition according to claim 1, wherein the component (A) is a di (meth) acrylate of a diol having 2 to 10 carbon atoms. For example, the photocurable adhesive composition of claim 1, wherein the component (B) is a diglycidyl glycol having a carbon number of 2 to 10 other than a polyether diol having an alkylene oxide unit repeating number of 3 or more. Based ether. The photocurable adhesive composition according to claim 1, wherein the component (C) is an oxetane compound represented by the following formula (1): For example, the photocurable adhesive composition of claim 1, wherein the content ratios of (A) component, (B) component, (C) component, (D) component, and (E) component in the composition are: 10 ~ 45 wt%, 5 ~ 35 wt%, 5 ~ 35 wt%, 2 ~ 20 wt%, and 2 ~ 6 wt%. The photocurable adhesive composition according to claim 1, wherein the (D) component contains 5 to 95% by weight (d1), 5 to 95% by weight (d2), and 0 in all constituent monomer units. ~ 80% by weight of (d3) polymer. The photocurable adhesive composition according to claim 1, wherein the component (D) is: 0 to 60% by weight of styrene or 0 to 40% by weight of carbon atoms having 1 in the total constituent monomer units. A ~ 10 hydrocarbon group and a propylene fluorene-based compound were used as a polymer of (d3). For example, the photocurable adhesive composition according to claim 7, wherein (D) component is: in all constituent monomer units, 10 to 60% by weight of glycidyl methacrylate is included as (d1), and 10 to 80% A polymer obtained by weight percent methyl methacrylate as (d2), and containing 1 to 50 weight percent styrene as (d3), and performing high temperature polymerization at a temperature of 160 ° C. or higher. For example, the photocurable adhesive composition according to claim 7, wherein (D) component is: in all constituent monomer units, 10 to 60% by weight of glycidyl methacrylate is included as (d1), and 10 to 80% (D2) by weight% of methyl methacrylate, and (d3) a compound containing 1 to 30% by weight of a hydrocarbon group having 1 to 10 carbon atoms and an acrylofluorenyl group. Polymer obtained by polymerization. The photocurable adhesive composition according to claim 1, further comprising (F) a photoradical polymerization initiator in the composition in a proportion of 10% by weight or less. The photocurable adhesive composition according to claim 1, further comprising a leveling agent in the composition as a component (G) in an amount of 0.01 to 0.5% by weight. A polarizing plate comprising a group consisting of a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin resin is bonded to a polarizer including a polyvinyl alcohol resin film with an adhesive. The polarizing plate formed from the protective film of the transparent resin film selected in the above is characterized in that the adhesive is formed of the photocurable adhesive composition according to any one of claims 1 to 11. A method for producing a polarizing plate, comprising laminating a polyester resin, a polycarbonate resin, an acrylic resin, and an amorphous polyolefin resin with an adhesive on a polarizer including a polyvinyl alcohol resin film with an adhesive. The method of manufacturing a polarizing plate by using a protective film of a transparent resin film selected from the group includes a step of applying an adhesive, and at least one of the bonding surfaces of the polarizer and the protective film. Apply the photocurable adhesive composition according to any one of claims 1 to 11; apply the bonding step, and attach the polarizer and the protective film through the obtained adhesive layer; This adhesive layer is hardened in the state which bonded the polarizer and the protective film. An optical member characterized in that another optical layer is laminated on a polarizing plate as in claim 12. The optical member as claimed in claim 14, wherein the other optical layer includes a retardation plate. A liquid crystal display device is characterized by arranging an optical member as claimed in claim 14 on one or both sides of a liquid crystal cell.