JP6298248B2 - Active energy ray-curable adhesive composition, polarizing plate, optical film, and image display device - Google Patents

Description

  The present invention relates to an active energy ray-curable adhesive composition for forming an adhesive layer for adhering two or more members, particularly an active energy ray-curable adhesive for forming an adhesive layer between a polarizer and a transparent protective film. The present invention relates to a composition and a polarizing plate. The polarizing plate can form an image display device such as a liquid crystal display device (LCD), an organic EL display device, a CRT, or a PDP alone or as an optical film in which the polarizing plate is laminated.

  Liquid crystal display devices are rapidly expanding in watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, and the like. The liquid crystal display device visualizes the polarization state by switching of the liquid crystal, and a polarizer is used from the display principle. In particular, in applications such as TVs, higher brightness, higher contrast, and wider viewing angles are required, and polarizing plates are also required to have higher transmittance, higher degree of polarization, and higher color reproducibility.

  As the polarizer, since it has a high transmittance and a high degree of polarization, for example, an iodine-based polarizer having a stretched structure by adsorbing iodine to polyvinyl alcohol (hereinafter also simply referred to as “PVA”) is most widely used. It is used. In general, a polarizing plate is used in which a transparent protective film is bonded to both surfaces of a polarizer with a so-called aqueous adhesive in which a polyvinyl alcohol-based material is dissolved in water (Patent Document 1 and Patent Document 2 below). ). As the transparent protective film, triacetyl cellulose having a high moisture permeability is used.

  When manufacturing a polarizing plate, when a water-based adhesive such as a polyvinyl alcohol-based adhesive is used (so-called wet lamination), a drying step is required after the polarizer and the transparent protective film are bonded together. . In order to improve the productivity of the polarizing plate, it is desirable to shorten the drying process or adopt another bonding method that does not require the drying process.

  In addition, when using a water-based adhesive, in order to enhance the adhesion with the polarizer, the water content of the polarizer must be relatively high (usually the water content of the polarizer is about 30%). A polarizing plate with good adhesion cannot be obtained. However, the polarizing plate thus obtained has problems such as large dimensional change and poor optical characteristics under high temperature and high temperature and high humidity. On the other hand, in order to suppress a dimensional change, the moisture content of a polarizer can be reduced or a transparent protective film with low moisture permeability can be used. However, when such a polarizer and a transparent protective film are bonded together using a water-based adhesive, drying efficiency decreases, polarization characteristics decrease, or appearance defects occur, and a substantially useful polarizing plate is obtained. I can't.

  In addition, as represented by TVs in particular, as the screen size of image display devices has increased in recent years, it has become very important to increase the size of polarizing plates in terms of productivity and cost (yield and increase in number of products). Yes. However, in the polarizing plate using the water-based adhesive described above, the so-called light leakage (unevenness) that the polarizing plate causes a dimensional change due to the heat of the backlight and becomes uneven and the black display appears white in a part of the entire screen. ) Becomes prominent.

  In order to solve the above-described problems in wet lamination, an active energy ray-curable adhesive that does not contain water or an organic solvent has been proposed. For example, in the following Patent Document 3, (A) a radical polymerizable compound containing a polar group and having a molecular weight of 1,000 or less, and (B) a radical polymerizable compound containing no polar group and having a molecular weight of 1,000 or less, An active energy ray curable adhesive containing (D) a photopolymerization initiator is disclosed. However, the combination of radically polymerizable compounds (monomers) constituting such an adhesive is designed particularly for the purpose of improving the adhesion to norbornene-based resin films, and therefore tends to have poor adhesion to the polarizing film. It was.

  Patent Document 4 below discloses an active energy ray-curable adhesive having a photopolymerization initiator having a molar extinction coefficient of 400 or more at a wavelength of 360 to 450 nm and an ultraviolet curable compound as essential components. However, since the combination of monomers constituting such an adhesive is designed mainly for the purpose of preventing warpage and deformation when adhering an optical disk or the like, when used for a polarizing film, There was a tendency to be inferior in adhesiveness.

  In the following Patent Document 5, (a) a (meth) acrylic compound having two or more (meth) acryloyl groups in the molecule in a total amount of 100 parts by weight of the (meth) acrylic compound, and (b) a hydroxyl group in the molecule. And an active energy ray-curable adhesive containing (meth) acrylic compound having only one polymerizable double bond and (c) phenolethylene oxide-modified acrylate or nonylphenolethylene oxide-modified acrylate ing. However, there is a concern that the combination of monomers constituting such an adhesive has relatively low compatibility between the monomers, phase separation proceeds accordingly, and transparency of the adhesive layer decreases. Further, such an adhesive is intended to improve adhesion by softening a cured product (adhesive layer) (lowering Tg), and there is a concern that durability such as crack resistance is deteriorated. The crack resistance can be evaluated by a thermal shock test (heat shock test).

  The present inventors have developed a radical polymerization type active energy ray-curable adhesive using an N-substituted amide monomer as a curable component (Patent Document 6 and Patent Document 7 below). Such an adhesive exhibits excellent durability under harsh environments under high humidity and high temperature. However, in the market, there is a demand for an adhesive that can further improve adhesiveness and / or water resistance. There was a real situation.

JP 2006-220732 A JP 2001-296427 A JP 2008-009329 A JP 09-31416 A JP 2008-174667 A JP 2008-287207 A JP 2010-78700 A

  The present invention has been made in view of the above circumstances, and its purpose is to improve adhesion between two or more members, particularly a polarizer and a transparent protective film layer, and to improve durability and water resistance. An active energy ray-curable adhesive composition capable of forming an agent layer, a polarizing plate, an optical film, and an image display device are provided.

  In order to solve the above-mentioned problems, the present inventors paid attention to the SP value (solubility parameter) of the curable component in the active energy ray-curable adhesive composition. In general, it can be said that substances having close SP values have high affinity. Therefore, for example, when the SP values of the radical polymerizable compounds are close to each other, the compatibility thereof increases, and when the SP values of the radical polymerizable compound and the polarizer in the active energy ray-curable adhesive composition are close, Adhesiveness between the adhesive layer and the polarizer is enhanced. Similarly, when the SP value of the radical polymerizable compound in the active energy ray-curable adhesive composition and the protective film (triacetyl cellulose film (TAC), acrylic film, cycloolefin film) is close, the adhesive layer and the protective layer are protected. Adhesion with the film increases. Based on these trends, as a result of intensive studies by the present inventors, in the active energy ray-curable adhesive composition, each SP value of at least three types of radical polymerizable compounds is designed within a specific range, And it discovered that the said subject could be solved by setting it as the optimal composition ratio. The present invention has been made as a result of the above-described studies, and achieves the above-described object with the following configuration.

That is, the active energy ray-curable adhesive composition according to the present invention is an active energy ray-curable adhesive composition containing radically polymerizable compounds (A), (B) and (C) as curable components. In addition, when the total amount of the composition is 100% by weight, the SP value is 29.0 ( M J / m ³ ) ^1/2 or more and 32.0 ( M J / m ³ ) ^1/2 or less. Radical polymerizable compound (B) having 20 to 60% by weight of compound (A) and SP value of 18.0 ( M J / m ³ ) ^1/2 or more and less than 21.0 ( M J / m ³ ) ^1/2 10) to 30% by weight, and a radically polymerizable compound (C) having an SP value of 21.0 ( M J / m ³ ) ^1/2 or more and 23.0 ( M J / m ³ ) ^1/2 or less 20 to 60% by weight, the radical polymerizable compounds (A), (B) and (C) Wherein the glass transition temperature of the respective homopolymer (Tg) of at both 60 ° C. or higher.

In the active energy ray-curable adhesive composition according to the present invention, the SP value of the radical polymerizable compound (A) is 29.0 ( M J / m ³ ) ^1/2 or more and 32.0 ( M J / m ³ ). ^{When the} total amount of the composition is 100% by weight, the composition ratio is 20 to 60% by weight. Such a radical polymerizable compound (A) has a high SP value, for example, a PVA polarizer (for example, SP value 32.8), a saponified triacetyl cellulose (for example, SP value 32.7) as a transparent protective film, and an adhesive. This greatly contributes to improving the adhesion with the layer. On the other hand, since the radically polymerizable compound (A) has an SP value relatively close to water (SP value 47.9), if the composition ratio of the radically polymerizable compound (A) in the composition is too large, There is concern about deterioration of the water resistance of the agent layer. Therefore, considering the adhesiveness with a polarizer, saponified triacetyl cellulose, and water resistance, it is important that the composition ratio of the radical polymerizable compound (A) is 20 to 60% by weight. In consideration of adhesiveness, the composition ratio of the radical polymerizable compound (A) is preferably 25% by weight or more, and more preferably 30% by weight or more. In consideration of water resistance, the composition ratio of the radical polymerizable compound (A) is preferably 55% by weight or less, and more preferably 50% by weight or less.

The SP value of the radical polymerizable compound (B) is 18.0 ( M J / m ³ ) ^1/2 or more and less than 21.0 ( M J / m ³ ) ^1/2 , and the composition ratio is 10 to 30 weights. %. Such radically polymerizable compound (B) has a low SP value, and is far away from water (SP value 47.9), which greatly contributes to improving the water resistance of the adhesive layer. The SP value of the radical polymerizable compound (B) is, for example, the SP value (for example, SP value 18.6) of a cyclic polyolefin resin (for example, trade name “ZEONOR” manufactured by Nippon Zeon Co., Ltd.) as a transparent protective film. Since it is near, it contributes also to the adhesive improvement with this transparent protective film. In order to further improve the water resistance of the adhesive layer, the SP value of the radical polymerizable compound (B) is preferably less than 20.0 ( M J / m ³ ) ^1/2 . On the other hand, since the radically polymerizable compound (B) has a large SP value from the radically polymerizable compound (A), if the composition ratio is too large, the compatibility balance between the radically polymerizable compounds is lost. As the phase separation proceeds, there is a concern that the transparency of the adhesive layer may deteriorate. Therefore, when considering water resistance and transparency of the adhesive layer, it is important that the composition ratio of the radical polymerizable compound (B) is 10 to 30% by weight. In consideration of water resistance, the composition ratio of the radical polymerizable compound (B) is preferably 10% by weight or more, and more preferably 15% by weight or more. In consideration of the transparency of the adhesive layer, the composition ratio of the radical polymerizable compound (B) is preferably 25% by weight or less, more preferably 20% by weight or less, and its SP value is 19 0.0 ( M J / m ³ ) ^1/2 or more is preferable.

The SP value of the radical polymerizable compound (C) is 21.0 ( M J / m ³ ) ^1/2 or more and less than 23.0 ( M J / m ³ ) ^1/2 , and the composition ratio is 20 to 60 weights. %. As described above, the radically polymerizable compound (A) and the radically polymerizable compound (B) have a large SP value and are not compatible with each other. However, since the SP value of the radical polymerizable compound (C) is located between the SP value of the radical polymerizable compound (A) and the SP value of the radical polymerizable compound (B), the radical polymerizable compound (A) In addition to the radically polymerizable compound (B) and the radically polymerizable compound (C), the compatibility of the composition as a whole is improved in a well-balanced manner. Furthermore, the SP value of the radical polymerizable compound (C) is close to the SP value (for example, 23.3) of unsaponified triacetyl cellulose as a transparent protective film and the SP value (for example, 22.2) of an acrylic film, for example. It also contributes to the improvement of adhesion with these transparent protective films. Therefore, in order to improve water resistance and adhesiveness in a well-balanced manner, it is important that the composition ratio of the radical polymerizable compound (C) is 20 to 60% by weight. When considering the compatibility of the composition as a whole and the adhesion to the transparent protective film, the composition ratio of the radical polymerizable compound (C) is preferably 25% by weight or more, and more preferably 29% by weight or more. In consideration of water resistance, the composition ratio of the radical polymerizable compound (C) is preferably 55% by weight or less, and more preferably 50% by weight or less.

  Further, since the glass transition temperature (Tg) of each of the radical polymerizable compounds (A), (B) and (C) is 60 ° C. or more, the durability is particularly excellent, and heat shock cracks Can be prevented. Here, “heat shock crack” means, for example, a phenomenon in which when a polarizer contracts, it tears in the stretching direction, and in order to prevent this, it is polarized in a heat shock temperature range (−40 ° C. to 60 ° C.). It is important to suppress the expansion / contraction of the child. As described above, since the glass transition temperature (Tg) of each of the radical polymerizable compounds (A), (B), and (C) is 60 ° C. or higher, when the adhesive layer is formed, the Tg is Get higher. As a result, a rapid change in elastic modulus of the adhesive layer in the heat shock temperature range can be suppressed, and the expansion / contraction force acting on the polarizer can be reduced, so that the occurrence of heat shock cracks can be prevented. .

  Here, the calculation method of SP value (solubility parameter) in this invention is demonstrated below.

(Calculation method of solubility parameter (SP value))
In the present invention, the solubility parameter (SP value) of a radically polymerizable compound, a polarizer, various transparent protective films and the like is calculated by the Fedors calculation method ["Polymer Engineering &Sci." 14, Vol. 2 (1974), pages 148-154]

（ただしΔｅｉは原子または基に帰属する２５℃における蒸発エネルギー、Δｖｉは２５℃におけるモル体積である）にて計算して求めることができる。

(Where Δei is the evaporation energy at 25 ° C. belonging to the atom or group, and Δvi is the molar volume at 25 ° C.).

  In the above formula, Δei and Δvi indicate constant numerical values given to i atoms and groups in the main molecule. Also, representative examples of numerical values of Δe and Δv given to atoms or groups are shown in Table 1 below.

In the active energy ray-curable adhesive composition, when the total amount of the radical polymerizable compound in the active energy ray-curable adhesive composition is 100 parts by weight, the radical polymerizable compounds (A), (B) and (C) is contained in a total of 85 to 100 parts by weight, and the SP value is more than 23.0 ( M J / m ³ ) ^1/2 and less than 29.0 ( M J / m ³ ) ^1/2 It is preferable to contain 0-15 weight part of radically polymerizable compounds (D). According to such a configuration, since the ratio of the radical polymerizable compounds (A), (B) and (C) in the adhesive composition can be sufficiently ensured, the adhesiveness of the adhesive layer is improved, and the durability and Water resistance can be further improved. In order to further improve the adhesion, durability and water resistance in a well-balanced manner, the radically polymerizable compounds (A), (B) and (C) are preferably contained in a total of 90 to 100 parts by weight, It is more preferable to contain parts by weight.

  In the active energy ray-curable adhesive composition, the radical polymerizable compound (A) is preferably hydroxyethyl acrylamide and / or N-methylol acrylamide. In the active energy ray-curable adhesive composition, the radical polymerizable compound (B) is preferably tripropylene glycol diacrylate. Furthermore, in the active energy ray-curable adhesive composition, the radical polymerizable compound (C) is preferably acryloylmorpholine and / or N-methoxymethylacrylamide. According to these structures, the adhesiveness, durability, and water resistance of the adhesive layer can be improved in a balanced manner.

（式中、Ｒ^１およびＲ^２は−Ｈ、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^１およびＲ^２は同一または異なっても良い）を含有することが好ましい。 In the active energy ray-curable adhesive composition, as a photopolymerization initiator, a compound represented by the following general formula (1);

(Wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different).

  Since the photopolymerization initiator of the general formula (1) can initiate polymerization by light having a long wavelength that passes through a transparent protective film having UV absorption ability, the adhesive can be cured even through a UV absorbing film. Specifically, for example, even when laminating a transparent protective film having UV absorbing ability on both sides like triacetylcellulose-polarizer-triacetylcellulose, when containing the photopolymerization initiator of the general formula (1), Curing of the adhesive composition is possible.

（式中、Ｒ^３、Ｒ^４およびＲ^５は−Ｈ、−ＣＨ_３、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^３、Ｒ^４およびＲ^５は同一または異なっても良い）を含有することが好ましい。上記一般式（１）および一般式（２）の光重合開始剤を併用することで、これらの光増感反応により反応が高効率化し、接着剤層の接着性が特に向上する。 Moreover, in the said active energy ray hardening-type adhesive composition, in addition to the photoinitiator of General formula (1) as a photoinitiator, the compound represented by following General formula (2);

Wherein R ³ , R ⁴ and R ⁵ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different. It is preferable to contain. By using together the photoinitiator of the said General formula (1) and General formula (2), reaction becomes highly efficient by these photosensitization reaction, and the adhesiveness of an adhesive bond layer improves especially.

  The polarizing plate according to the present invention is a polarizing plate in which a transparent protective film having a light transmittance of a wavelength of 365 nm of less than 5% is provided on at least one surface of a polarizer via an adhesive layer. The adhesive layer is formed of a cured product layer formed by irradiating the active energy ray-curable adhesive composition according to any one of the above with active energy rays.

  As described above, the polarizer has a high SP value (the SP value of the PVA polarizer is 32.8, for example), while the transparent protective film generally has a low SP value (the SP value is about 18 to 24). The polarizing plate according to the present invention includes a radically polymerizable compound (A) in an active energy ray-curable adhesive composition that forms an adhesive layer that adheres a polarizer having a high SP value and a transparent protective film having a low SP value. ), (B) and (C) are designed to optimize the SP value and blending amount. As a result, in such a polarizing plate, the polarizer and the transparent protective film are firmly bonded via the adhesive layer, and the durability and water resistance of the adhesive layer are excellent. In particular, when the Tg of the adhesive layer is 60 ° C. or higher, more preferably 70 ° C. or higher, particularly preferably 90 ° C. or higher, the durability is particularly excellent, and the occurrence of heat shock cracks can be prevented.

  The optical film according to the present invention is characterized in that at least one polarizing plate described above is laminated.

In the polarizing plate, the transparent protective film preferably has an SP value of 29.0 ( M J / m ³ ) ^1/2 or more and less than 33.0 ( M J / m ³ ) ^1/2 . When the SP value of the transparent protective film is within the above range, it is very close to the SP value of the radical polymerizable compound (A) in the active energy ray-curable adhesive composition. Adhesion is greatly improved. Examples of the transparent protective film having an SP value of 29.0 ( M J / m ³ ) ^1/2 or more and less than 33.0 ( M J / m ³ ) ^1/2 include, for example, saponified triacetyl cellulose (for example, SP value 32). .7).

In the polarizing plate, the transparent protective film preferably has an SP value of 18.0 ( M J / m ³ ) ^1/2 or more and less than 24.0 ( M J / m ³ ) ^1/2 . If the SP value of the transparent protective film is within the above range, it is very close to the SP value of the radical polymerizable compound (B) and the radical polymerizable compound (C) in the active energy ray-curable adhesive composition. The adhesion between the protective film and the adhesive layer is greatly improved. The transparent protective film having an SP value of 18.0 ( M J / m ³ ) ^1/2 or more and less than 24.0 ( M J / m ³ ) ^1/2 is, for example, unsaponified triacetyl cellulose (for example, SP value) 23.3).

  Furthermore, the image display device according to the present invention is characterized by using the polarizing plate and / or the optical film described above. In such an optical film and image display device, the polarizer of the polarizing plate and the transparent protective film are firmly bonded via the adhesive layer, and the durability and water resistance of the adhesive layer are excellent.

  When the adhesive layer is formed from the cured product of the active energy ray-curable adhesive composition according to the present invention, the adhesion between two or more members, particularly the polarizer and the transparent protective film layer, is improved and the durability is improved. In addition, an adhesive layer with improved water resistance can be formed.

  When the adhesive layer according to the present invention is provided, a polarizing plate with a small dimensional change can be produced, so that it is possible to easily cope with an increase in the size of the polarizing plate, and it is possible to suppress the production cost from the viewpoint of yield and number of production. Further, since the polarizing plate according to the present invention has good dimensional stability, it is possible to suppress the occurrence of unevenness in the image display device due to the external heat of the backlight.

The active energy ray-curable adhesive composition according to the present invention has an SP value of 29.0 ( M J / m ³ ) ^1/2 or more when the total amount of the composition is 100% by weight as a curable component. 20 to 60% by weight of the radically polymerizable compound (A) which is 0 ( M J / m ³ ) ^1/2 or less, and the SP value is 18.0 ( M J / m ³ ) ^1/2 or more and 21.0 ( M J / m ³ ) 10 to 30% by weight of the radical polymerizable compound (B) which is less than ^1/2 , and the SP value is 21.0 ( M J / m ³ ) ^1/2 or more and 23.0 ( M J / m ³ ) 20 to 60% by weight of the radically polymerizable compound (C) which is ^1/2 or less. In the present invention, the “composition total amount” means the total amount including various initiators and additives in addition to the radical polymerizable compound.

The radical polymerizable compound (A) has a radical polymerizable group such as a (meth) acrylate group, and has an SP value of 29.0 ( M J / m ³ ) ^1/2 or more and 32.0 ( M J / m ³ ) ^Any compound that is ^½ or less can be used without limitation. Specific examples of the radical polymerizable compound (A) include hydroxyethyl acrylamide (SP value 29.6), N-methylol acrylamide (SP value 31.5) and the like. In the present invention, the (meth) acrylate group means an acrylate group and / or a methacrylate group.

The radically polymerizable compound (B) has a radically polymerizable group such as a (meth) acrylate group and has an SP value of 18.0 ( M J / m ³ ) ^1/2 or more and 21.0 ( M J / m ³ ) ^Any compound that is less than ^½ can be used without limitation. Specific examples of the radically polymerizable compound (B) include, for example, tripropylene glycol diacrylate (SP value 19.0), 1,9-nonanediol diacrylate (SP value 19.2), and tricyclodecane dimethanol dimer. Acrylate (SP value 20.3), cyclic trimethylolpropane formal acrylate (SP value 19.1), dioxane glycol diacrylate (SP value 19.4), EO-modified diglycerin tetraacrylate (SP value 20.9), etc. Is mentioned. In addition, as a radically polymerizable compound (B), a commercial item can also be used conveniently, for example, Aronix M-220 (made by Toagosei Co., Ltd., SP value 19.0), light acrylate 1,9ND-A (Kyoeisha Chemical Co., Ltd.). Manufactured, SP value 19.2), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., SP value 20.9), light acrylate DCP-A (manufactured by Kyoeisha Chemical Co., SP value 20.3), SR-531 (Sartomer) And SP-value 19.1), CD-536 (Sartomer, SP value 19.4), and the like.

The radical polymerizable compound (C) has a radical polymerizable group such as a (meth) acrylate group and has an SP value of 21.0 ( M J / m ³ ) ^1/2 or more and 23.0 ( M J / m ³ ) ^Any compound that is ^½ or less can be used without limitation. Specific examples of the radical polymerizable compound (C) include, for example, acryloylmorpholine (SP value 22.9), N-methoxymethylacrylamide (SP value 22.9), N-ethoxymethylacrylamide (SP value 22.3). Etc. In addition, as a radically polymerizable compound (C), a commercial item can also be used suitably, for example, ACMO (the Kojin company make, SP value 22.9), Wasmer 2MA (the Kasano Kosan company make, SP value 22.9). , Wasmer EMA (manufactured by Kasano Kosan Co., Ltd., SP value 22.3), Wasmer 3MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.4), and the like.

  When the glass transition temperature (Tg) of each of the radical polymerizable compounds (A), (B), and (C) is 60 ° C. or higher, the Tg of the adhesive layer is increased and the durability is particularly excellent. It will be. As a result, for example, when an adhesive layer of a polarizer and a transparent protective film is used, occurrence of heat shock cracks in the polarizer can be prevented. Here, the Tg of the homopolymer of the radical polymerizable compound means Tg when the radical polymerizable compound is cured (polymerized) alone. A method for measuring Tg will be described later.

The active energy ray-curable adhesive composition according to the present invention contains 85 to 100 parts by weight of radically polymerizable compounds (A), (B) and (C) in total, and further has an SP value of 23.0 ( M J ^/ m ^{3) 1/2} beyond 29.0 (M ^J / ^{m 3)} radically polymerizable compound is less than ^1/2 the (D) may contain 0 to 15 parts by weight. Specific examples of the radical polymerizable compound (D) include, for example, 4-hydroxybutyl acrylate (SP value 23.8), 2-hydroxyethyl acrylate (SP value 25.5), N-vinylcaprolactam (trade name V- CAP, manufactured by ISP, SP value 23.4), 2-hydroxypropyl acrylate (SP value 24.5), and the like.

  When the active energy ray curable adhesive composition according to the present invention is used in an electron beam curable type, it is not particularly necessary to include a photopolymerization initiator in the composition, but when used in an ultraviolet curable type, It is preferable to use a photopolymerization initiator, and it is particularly preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more. A photopolymerization initiator that is highly sensitive to light of 380 nm or more will be described later.

（式中、Ｒ^１およびＲ^２は−Ｈ、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^１およびＲ^２は同一または異なっても良い）を単独で使用するか、あるいは一般式（１）で表される化合物と後述する３８０ｎｍ以上の光に対して高感度な光重合開始剤とを併用することが好ましい。一般式（１）で表される化合物を使用した場合、３８０ｎｍ以上の光に対して高感度な光重合開始剤を単独で使用した場合に比べて接着性に優れる。一般式（１）で表される化合物の中でも、Ｒ^１およびＲ^２が−ＣＨ_２ＣＨ_３であるジエチルチオキサントンが特に好ましい。組成物中の一般式（１）で表される化合物の組成比率は、組成物全量を１００重量％としたとき、０．１〜５．０重量％であることが好ましく、０．５〜４．０重量％であることがより好ましく、０．９〜３．０重量％であることがさらに好ましい。 In the active energy ray-curable adhesive composition according to the present invention, as a photopolymerization initiator, a compound represented by the following general formula (1);

(Wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different), respectively, or a general formula ( It is preferable to use together the compound represented by 1) and a photopolymerization initiator that is highly sensitive to light of 380 nm or more, which will be described later. When the compound represented by the general formula (1) is used, the adhesiveness is excellent as compared with a case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are —CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound represented by the general formula (1) in the composition is preferably 0.1 to 5.0% by weight when the total amount of the composition is 100% by weight, and preferably 0.5 to 4%. It is more preferably 0.0% by weight, and even more preferably 0.9 to 3.0% by weight.

  Moreover, it is preferable to add a polymerization initiation assistant as required. Examples of polymerization initiators include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and the like. Among them, ethyl 4-dimethylaminobenzoate is particularly preferable. When a polymerization initiation assistant is used, the addition amount is usually 0 to 5% by weight, preferably 0 to 4% by weight, most preferably 0 to 3% by weight when the total amount of the composition is 100% by weight. .

  Moreover, a well-known photoinitiator can be used together as needed. Since the transparent protective film having UV absorbing ability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more as the photopolymerization initiator. Specifically, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 2- (Dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine Oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole) 1-yl) -phenyl) titanium and the like.

（式中、Ｒ^３、Ｒ^４およびＲ^５は−Ｈ、−ＣＨ_３、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^３、Ｒ^４およびＲ^５は同一または異なっても良い）を使用することが好ましい。一般式（２）で表される化合物としては、市販品でもある２−メチル−１−（４−メチルチオフェニル）−２−モルフォリノプロパン−１−オン（商品名：ＩＲＧＡＣＵＲＥ９０７ メーカー：ＢＡＳＦ）が好適に使用可能である。その他、２−ベンジル−２−ジメチルアミノ−１−（４−モルフォリノフェニル）−ブタノン−１（商品名：ＩＲＧＡＣＵＲＥ３６９ メーカー：ＢＡＳＦ）、２−（ジメチルアミノ）−２−［（４−メチルフェニル）メチル］−１−［４−（４−モルホリニル）フェニル］−１−ブタノン（商品名：ＩＲＧＡＣＵＲＥ３７９ メーカー：ＢＡＳＦ）が感度が高いため好ましい。 In particular, as a photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (1), a compound represented by the following general formula (2);

Wherein R ³ , R ⁴ and R ⁵ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different. It is preferable to use it. As the compound represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907 manufacturer: BASF) which is also a commercially available product is suitable. Can be used. In addition, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: IRGACURE369 manufacturer: BASF), 2- (dimethylamino) -2-[(4-methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (trade name: IRGACURE379 manufacturer: BASF) is preferable because of its high sensitivity.

  Moreover, the active energy ray hardening-type adhesive composition which concerns on this invention can mix | blend various additives as another arbitrary component in the range which does not impair the objective and effect of this invention. Such additives include epoxy resin, polyamide, polyamideimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene-butadiene block copolymer, petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based oligomer, Polymers or oligomers such as silicone oligomers and polysulfide oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiation aids; leveling agents; wettability improvers; Plasticizer; UV absorber; Silane coupling agent; Inorganic filler; Pigment;

  Among the above additives, the silane coupling agent acts on the polarizer surface and can impart further water resistance. When a silane coupling agent is used, the amount added is usually 0 to 10% by weight, preferably 0 to 5% by weight, most preferably 0 to 3% by weight when the total amount of the composition is 100% by weight. .

  As the silane coupling agent, an active energy ray-curable compound is preferably used, but the same water resistance can be imparted even if it is not active energy ray-curable.

  Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, and 3-glycid as active energy ray-curable compounds. Xylpropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxy Examples thereof include silane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

  Specific examples of silane coupling agents that are not active energy ray curable include N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2. (Aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N -Phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3 -Mercaptopropylmethyldimethoxysilane, - mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanate propyltriethoxysilane, etc. imidazole silane.

  Preferable are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

  The active energy ray-curable adhesive composition according to the present invention can be used in an electron beam curable type or an ultraviolet curable type.

  In the electron beam curable type, any appropriate condition can be adopted as the irradiation condition of the electron beam as long as the active energy ray curable adhesive composition can be cured. For example, in the electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive and may be insufficiently cured. If the acceleration voltage exceeds 300 kV, the penetration force through the sample is too strong and damages the transparent protective film and the polarizer. There is a risk of giving. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive becomes insufficiently cured, and when it exceeds 100 kGy, the transparent protective film and the polarizer are damaged, resulting in a decrease in mechanical strength and yellowing, thereby obtaining predetermined optical characteristics. I can't.

  Electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or under a condition in which a small amount of oxygen is introduced. Depending on the material of the transparent protective film, by appropriately introducing oxygen, the transparent protective film surface where the electron beam first hits can be obstructed to prevent oxygen damage and prevent damage to the transparent protective film. An electron beam can be irradiated efficiently.

  On the other hand, in the case of using a transparent protective film imparted with ultraviolet absorbing ability in the ultraviolet curable type, light having a wavelength shorter than about 380 nm is absorbed. Therefore, light having a wavelength shorter than 380 nm is applied to the active energy ray curable adhesive composition. Since it does not reach, it does not contribute to the polymerization reaction. Further, light having a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curling and wrinkling of the polarizing plate. Therefore, when the ultraviolet curable type is adopted in the present invention, it is preferable to use an apparatus that does not emit light having a wavelength shorter than 380 nm as the ultraviolet ray generating apparatus, and more specifically, the integrated illuminance and wavelength in the wavelength range of 380 to 440 nm. The ratio with the integrated illuminance in the range of 250 to 370 nm is preferably 100: 0 to 100: 50, and more preferably 100: 0 to 100: 40. As the ultraviolet ray satisfying such a relationship of integrated illuminance, a gallium-filled metal halide lamp and an LED light source that emits light in the wavelength range of 380 to 440 nm are preferable. Alternatively, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or sunlight as the light source, It is also possible to use a light having a wavelength shorter than 380 nm by using a band pass filter.

  In the ultraviolet curable type, it is preferable to warm the active energy ray-curable adhesive composition before irradiation with ultraviolet rays (heating before irradiation), in which case it is preferable to warm to 40 ° C. or higher, and 50 ° C. or higher. It is more preferable to heat the sample. In addition, it is also preferable to heat the active energy ray-curable adhesive composition after irradiation with ultraviolet rays (heating after irradiation), in which case it is preferable to heat to 40 ° C. or higher, and to warm to 50 ° C. or higher. Is more preferable.

  The active energy ray-curable adhesive composition according to the present invention can be suitably used particularly when forming an adhesive layer that bonds a polarizer and a transparent protective film having a light transmittance of less than 5% at a wavelength of 365 nm. It is. Here, the active energy ray-curable adhesive composition according to the present invention irradiates ultraviolet rays through the transparent protective film having UV absorption ability by containing the photopolymerization initiator of the general formula (1) described above. Thus, the adhesive layer can be cured and formed. Therefore, an adhesive bond layer can be hardened also in the polarizing plate which laminated the transparent protective film which has UV absorption ability on both sides of a polarizer. However, as a matter of course, the adhesive layer can be cured also in a polarizing plate on which a transparent protective film having no UV absorbing ability is laminated. In addition, the transparent protective film which has UV absorption ability means the transparent protective film whose transmittance | permeability with respect to light of 380 nm is less than 10%.

  Examples of the method for imparting UV absorbing ability to the transparent protective film include a method of containing an ultraviolet absorber in the transparent protective film and a method of laminating a surface treatment layer containing an ultraviolet absorber on the surface of the transparent protective film.

  Specific examples of the ultraviolet absorber include conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, triazine compounds, and the like. .

  The adhesive layer formed by the active energy ray-curable adhesive composition has higher durability than the aqueous adhesive layer. In the present invention, it is preferable to use an adhesive layer having a Tg of 60 ° C. or higher. Moreover, it is preferable to control so that the thickness of an adhesive bond layer may be set to 0.01-7 micrometers. Thus, in the polarizing plate of the present invention, when using the active energy ray-curable adhesive composition in which the adhesive layer has a high Tg of 60 ° C. or higher and the thickness of the adhesive layer is controlled within the above range, Durability in harsh environments under high humidity and high temperature can be satisfied. In consideration of the durability of the polarizing plate, in the present invention, in particular, when Tg (° C.) of the adhesive layer is defined as A and the thickness (μm) of the adhesive layer is defined as B, Formula (1): A− It is preferable that 12 × B> 58 is satisfied.

  As described above, the active energy ray-curable adhesive composition is preferably selected so that the Tg of the adhesive layer formed thereby is 60 ° C. or higher, and more preferably 70 ° C. or higher. Further, it is preferably 75 ° C. or higher, more preferably 100 ° C. or higher, and further preferably 120 ° C. or higher. On the other hand, if the Tg of the adhesive layer becomes too high, the flexibility of the polarizing plate is lowered. Therefore, the Tg of the adhesive layer is preferably 300 ° C. or lower, more preferably 240 ° C. or lower, and further preferably 180 ° C. or lower.

  Moreover, as above-mentioned, the thickness of an adhesive bond layer becomes like this. Preferably it is 0.01-7 micrometers, More preferably, it is 0.01-5 micrometers, More preferably, it is 0.01-2 micrometers, Most preferably, it is 0.01-1 micrometer. When the thickness of the adhesive layer is thinner than 0.01 μm, the cohesive force of the adhesive layer itself cannot be obtained, and the adhesive strength may not be obtained. On the other hand, if the thickness of the adhesive layer exceeds 7 μm, the polarizing plate cannot satisfy the durability.

In the method for producing a polarizing plate according to the present invention, the active energy ray-curable adhesive composition is applied on the surface on which the adhesive layer of the polarizer is formed and / or on the surface on which the adhesive layer of the transparent protective film is formed. And a step of bonding the polarizer and the transparent protective film, and then a step of curing the active energy ray-curable adhesive composition by active energy ray irradiation to form an adhesive layer.

  The polarizer and the transparent protective film may be subjected to a surface modification treatment before applying the active energy ray-curable adhesive composition. Specific examples of the treatment include corona treatment, plasma treatment, and saponification treatment.

  The coating method of the active energy ray-curable adhesive composition is appropriately selected depending on the viscosity of the composition and the target thickness. Examples of coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters, rod coaters and the like. In addition, for coating, a method such as a dapping method can be appropriately used.

  A polarizer and a transparent protective film are bonded together through the adhesive applied as described above. Bonding of the polarizer and the transparent protective film can be performed with a roll laminator or the like.

  After bonding a polarizer and a transparent protective film, an active energy ray (an electron beam, ultraviolet rays, etc.) is irradiated, an active energy ray hardening-type adhesive composition is hardened, and an adhesive bond layer is formed. The irradiation direction of active energy rays (electron beam, ultraviolet ray, etc.) can be irradiated from any appropriate direction. Preferably, it irradiates from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beams, ultraviolet rays, etc.).

  When the polarizing plate according to the present invention is produced in a continuous line, the line speed depends on the curing time of the adhesive, but is preferably 1 to 500 m / min, more preferably 5 to 300 m / min, and still more preferably 10 to 100 m / min. min. When the line speed is too low, productivity is poor, or damage to the transparent protective film is too great, and a polarizing plate that can withstand a durability test or the like cannot be produced. When the line speed is too high, the adhesive is not sufficiently cured, and the target adhesiveness may not be obtained.

  In the polarizing plate of the present invention, a polarizer and a transparent protective film are bonded together via an adhesive layer formed of a cured product layer of the active energy ray-curable adhesive composition. An easily adhesive layer can be provided between the adhesive layer and the adhesive layer. The easy adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Moreover, you may add another additive for formation of an easily bonding layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat resistance stabilizer may be used.

  The easy adhesion layer is usually provided in advance on a transparent protective film, and the easy adhesion layer side of the transparent protective film and the polarizer are bonded together with an adhesive layer. The easy-adhesion layer is formed by coating and drying the material for forming the easy-adhesion layer on the transparent protective film by a known technique. The material for forming the easy-adhesion layer is usually adjusted as a solution diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating. The thickness of the easy adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and still more preferably 0.05 to 1 μm. Note that a plurality of easy-adhesion layers can be provided, but also in this case, the total thickness of the easy-adhesion layers is preferably in the above range.

  In the polarizing plate of the present invention, a transparent protective film is bonded to at least one surface of a polarizer via an adhesive layer formed by a cured product layer of the active energy ray-curable adhesive composition.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. And polyene-based oriented films such as those obtained by adsorbing a functional material and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared by, for example, dying a polyvinyl alcohol film in an aqueous solution of iodine and stretching it 3 to 7 times the original length. it can. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As the polarizer, a thin polarizer having a thickness of 10 μm or less can be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizer is preferable in that the thickness unevenness is small, the visibility is excellent, the dimensional change is small, the durability is excellent, and the thickness of the polarizing plate can be reduced.

  As the thin polarizer, representatively, JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, PCT / JP2010 / 001460 specification, or Japanese Patent Application 2010- The thin polarizing film described in 269002 specification and Japanese Patent Application No. 2010-263692 specification can be mentioned. These thin polarizing films can be obtained by a production method including a step of stretching and dyeing a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a stretching resin substrate in the state of a laminate. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching by being supported by the stretching resin substrate.

  As the thin polarizing film, among the production methods including the step of stretching in the state of a laminate and the step of dyeing, WO2010 / 100917 pamphlet, PCT / PCT / PCT / JP 2010/001460 specification, or Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 as described in the manufacturing method including a step of stretching in a boric acid aqueous solution is preferable. What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary | assistant before extending | stretching in the boric acid aqueous solution as described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 is preferable.

  The thin high-performance polarizing film described in the specification of PCT / JP2010 / 001460 is a thin film having a thickness of 7 μm or less made of a PVA-based resin oriented with a dichroic material, which is integrally formed on a resin base material. It is a high-functional polarizing film, and has optical properties such as a single transmittance of 42.0% or more and a degree of polarization of 99.95% or more.

  The thin high-performance polarizing film generates a PVA-based resin layer by applying and drying a PVA-based resin on a resin substrate having a thickness of at least 20 μm, and the generated PVA-based resin layer is used as a dichroic dyeing solution. So that the dichroic substance is adsorbed on the PVA resin layer, and the PVA resin layer on which the dichroic substance is adsorbed is integrated with the resin base material in the boric acid aqueous solution so that the total draw ratio is the original length. It can manufacture by extending | stretching so that it may become 5 times or more.

  Moreover, it is a method for producing a laminate film including a thin high-performance polarizing film in which a dichroic substance is oriented, and includes a resin base material having a thickness of at least 20 μm and a PVA resin on one side of the resin base material. The said laminated body containing the process of producing | generating the laminated body film containing the PVA-type resin layer formed by apply | coating and drying aqueous solution, and the PVA-type resin layer formed in the single side | surface of the resin base material A step of adsorbing the dichroic substance to the PVA resin layer contained in the laminate film by immersing the film in a dye solution containing the dichroic substance, and a PVA resin adsorbing the dichroic substance A step of stretching the laminate film including a layer in a boric acid aqueous solution so that the total stretching ratio is 5 times or more of the original length, and a PVA resin layer on which a dichroic substance is adsorbed Stretched together with As a result, a thickness of 7 μm or less, a single transmittance of 42.0% or more, and a degree of polarization of 99.95% or more are formed of a PVA resin layer in which a dichroic material is oriented on one side of a resin base material. The thin high-performance polarizing film can be manufactured by including a step of manufacturing a laminate film on which a thin high-performance polarizing film having the above optical characteristics is formed.

  The thin polarizing film described in Japanese Patent Application Nos. 2010-269002 and 2010-263692 is a continuous web polarizing film made of a PVA-based resin in which a dichroic material is oriented, A laminate including a PVA resin layer formed on a crystalline ester thermoplastic resin substrate is stretched in a two-stage stretching process consisting of air-assisted stretching and boric acid-water stretching to a thickness of 10 μm or less. It has been done. Such a thin polarizing film has P> − (100.929T-42.4-1) × 100 (where T <42.3) and P ≧ 99, where T is the single transmittance and P is the polarization degree. .9 (where T ≧ 42.3) is preferable.

  Specifically, the thin polarizing film is a stretch intermediate formed of an oriented PVA resin layer by high-temperature stretching in the air with respect to the PVA resin layer formed on the amorphous ester thermoplastic resin substrate of the continuous web. A colored intermediate product comprising a PVA-based resin layer in which a dichroic material (preferably iodine or a mixture of iodine and an organic dye) is oriented by adsorption of the dichroic material to the stretched intermediate product and a step of generating the product. A thin polarizing film comprising a step of forming a product, and a step of generating a polarizing film having a thickness of 10 μm or less comprising a PVA-based resin layer in which a dichroic material is oriented by stretching in a boric acid solution with respect to a colored intermediate product It can be manufactured by a manufacturing method.

In this production method, the total draw ratio of the PVA resin layer formed on the amorphous ester thermoplastic resin base material by high-temperature drawing in air and drawing in boric acid solution should be 5 times or more. desirable. The liquid temperature of the boric acid aqueous solution for boric-acid water extending | stretching can be 60 degreeC or more. Before stretching the colored intermediate product in the aqueous boric acid solution, it is desirable to insolubilize the colored intermediate product. In this case, the colored intermediate product is added to the aqueous boric acid solution whose liquid temperature does not exceed 40 ° C. It is desirable to do so by dipping. The amorphous ester-based thermoplastic resin base material is amorphous polyethylene containing copolymerized polyethylene terephthalate copolymerized with isophthalic acid, copolymerized polyethylene terephthalate copolymerized with cyclohexanedimethanol, or other copolymerized polyethylene terephthalate. It can be terephthalate and is preferably made of a transparent resin, and the thickness thereof can be 7 times or more the thickness of the PVA resin layer to be formed. Moreover, the draw ratio of the high temperature stretching in the air is preferably 3.5 times or less, and the stretching temperature of the high temperature stretching in the air is preferably not less than the glass transition temperature of the PVA resin, specifically in the range of 95 ° C to 150 ° C. When performing high temperature stretching in the air by free end uniaxial stretching, the total stretching ratio of the PVA resin layer formed on the amorphous ester thermoplastic resin base material is preferably 5 to 7.5 times . In addition, when performing high-temperature stretching in the air by uniaxial stretching at the fixed end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material is 5 times or more and 8.5 times or less. Is preferred.
More specifically, a thin polarizing film can be produced by the following method.

  A base material of a continuous web of isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) in which 6 mol% of isophthalic acid is copolymerized is prepared. The glass transition temperature of amorphous PET is 75 ° C. A laminate comprising a continuous web of amorphous PET substrate and a polyvinyl alcohol (PVA) layer is prepared as follows. Incidentally, the glass transition temperature of PVA is 80 ° C.

  A 200 μm-thick amorphous PET base material and a 4-5% concentration PVA aqueous solution in which PVA powder having a polymerization degree of 1000 or more and a saponification degree of 99% or more are dissolved in water are prepared. Next, a PVA aqueous solution is applied to a 200 μm thick amorphous PET substrate and dried at a temperature of 50 to 60 ° C. to obtain a laminate in which a 7 μm thick PVA layer is formed on the amorphous PET substrate. .

  A laminated body including a PVA layer having a thickness of 7 μm is subjected to the following steps including a two-step stretching process of air-assisted stretching and boric acid water stretching to produce a 3 μm-thick thin high-performance polarizing film. In the first-stage aerial auxiliary stretching step, the laminate including the 7 μm-thick PVA layer is integrally stretched with the amorphous PET substrate to produce a stretched laminate including the 5 μm-thick PVA layer. Specifically, in this stretched laminate, a laminate including a 7 μm-thick PVA layer is subjected to a stretching apparatus disposed in an oven set to a stretching temperature environment of 130 ° C. so that the stretching ratio is 1.8 times. Are stretched uniaxially at the free end. By this stretching treatment, the PVA layer contained in the stretched laminate is changed to a 5 μm thick PVA layer in which PVA molecules are oriented.

  Next, a colored laminate in which iodine is adsorbed on a PVA layer having a thickness of 5 μm in which PVA molecules are oriented is generated by a dyeing process. Specifically, this colored laminate has a single layer transmittance of the PVA layer constituting the high-functional polarizing film that is finally produced by using the stretched laminate in a staining solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. Iodine is adsorbed to the PVA layer contained in the stretched laminate by dipping for an arbitrary period of time so as to be 40 to 44%. In this step, the staining solution uses water as a solvent and an iodine concentration in the range of 0.12 to 0.30% by weight and a potassium iodide concentration in the range of 0.7 to 2.1% by weight. The concentration ratio of iodine and potassium iodide is 1 to 7. Incidentally, potassium iodide is required to dissolve iodine in water. More specifically, by immersing the stretched laminate in a dyeing solution having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight for 60 seconds, iodine is applied to a 5 μm-thick PVA layer in which PVA molecules are oriented. A colored laminate is adsorbed on the substrate.

  Further, the colored laminated body is further stretched integrally with the amorphous PET base material by the second stage boric acid underwater stretching step to produce an optical film laminate including a PVA layer constituting a highly functional polarizing film having a thickness of 3 μm. To do. Specifically, this optical film laminate is stretched by applying a colored laminate to a stretching apparatus provided in a treatment apparatus set to a boric acid aqueous solution having a liquid temperature range of 60 to 85 ° C. containing boric acid and potassium iodide. It is stretched uniaxially at the free end so that the magnification is 3.3 times. More specifically, the liquid temperature of the boric acid aqueous solution is 65 ° C. It also has a boric acid content of 4 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 5 parts by weight with respect to 100 parts by weight of water. In this step, the colored laminate with adjusted iodine adsorption amount is first immersed in a boric acid aqueous solution for 5 to 10 seconds. After that, the colored laminate is passed as it is between a plurality of sets of rolls having different peripheral speeds, which is a stretching apparatus provided in the processing apparatus, and the stretching ratio is freely increased to 3.3 times over 30 to 90 seconds. Stretch uniaxially. By this stretching treatment, the PVA layer contained in the colored laminate is changed into a PVA layer having a thickness of 3 μm in which the adsorbed iodine is oriented higher in one direction as a polyiodine ion complex. This PVA layer constitutes a highly functional polarizing film of the optical film laminate.

  Although not an indispensable step for the production of an optical film laminate, the optical film laminate was removed from the boric acid aqueous solution and adhered to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate by the washing step. It is preferable to wash boric acid with an aqueous potassium iodide solution. Thereafter, the washed optical film laminate is dried by a drying process using hot air at 60 ° C. The cleaning process is a process for eliminating appearance defects such as boric acid precipitation.

  Similarly, it is not an indispensable process for producing an optical film laminate, but an adhesive is applied to the surface of a 3 μm-thick PVA layer formed on an amorphous PET substrate by a bonding and / or transfer process. However, after bonding the 80 μm thick triacetyl cellulose film, the amorphous PET substrate can be peeled off, and the 3 μm thick PVA layer can be transferred to the 80 μm thick triacetyl cellulose film.

[Other processes]
The manufacturing method of said thin-shaped polarizing film may include another process other than the said process. Examples of other steps include an insolubilization step, a crosslinking step, and a drying (adjustment of moisture content) step. The other steps can be performed at any appropriate timing.
The insolubilization step is typically performed by immersing the PVA resin layer in a boric acid aqueous solution. By performing the insolubilization treatment, water resistance can be imparted to the PVA resin layer. The concentration of the boric acid aqueous solution is preferably 1 to 4 parts by weight with respect to 100 parts by weight of water. The liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C. Preferably, the insolubilization step is performed after the laminate is manufactured and before the dyeing step and the underwater stretching step.
The crosslinking step is typically performed by immersing the PVA resin layer in an aqueous boric acid solution. By performing the crosslinking treatment, water resistance can be imparted to the PVA resin layer. The concentration of the boric acid aqueous solution is preferably 1 to 4 parts by weight with respect to 100 parts by weight of water. Moreover, when performing a bridge | crosslinking process after the said dyeing | staining process, it is preferable to mix | blend iodide further. By blending iodide, elution of iodine adsorbed on the PVA resin layer can be suppressed. The blending amount of iodide is preferably 1 part by weight to 5 parts by weight with respect to 100 parts by weight of water. Specific examples of the iodide are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C. Preferably, the crosslinking step is performed before the second boric acid aqueous drawing step. In a preferred embodiment, the dyeing step, the crosslinking step, and the second boric acid aqueous drawing step are performed in this order.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) And polymers based on polycarbonate and polycarbonate. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Examples of the polymer that forms the transparent protective film include polymer blends. One or more kinds of arbitrary appropriate additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

  Moreover, as a transparent protective film, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007), for example, (A) thermoplastic resin which has a substituted and / or unsubstituted imide group in a side chain, ( B) Resin compositions containing a thermoplastic resin having substituted and / or unsubstituted phenyl and nitrile groups in the side chain. Specific examples include a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, problems such as unevenness due to the distortion of the polarizing plate can be eliminated, and since the moisture permeability is small, the humidification durability is excellent.

  Although the thickness of a transparent protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and a handleability, and thin-layer property. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

  In addition, when providing a transparent protective film on both surfaces of a polarizer, the transparent protective film which consists of the same polymer material may be used by the front and back, and the transparent protective film which consists of a different polymer material etc. may be used.

  A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer can be provided on the surface of the transparent protective film to which the polarizer is not adhered. The functional layers such as the hard coat layer, antireflection layer, antisticking layer, diffusion layer and antiglare layer can be provided on the transparent protective film itself, and separately provided separately from the transparent protective film. You can also.

  The polarizing plate of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), and a viewing angle compensation film One or more optical layers that may be used can be used. In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate or a semi-transmissive reflecting plate is further laminated on the polarizing plate of the present invention, an elliptical polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on the polarizing plate. A wide viewing angle polarizing plate obtained by further laminating a viewing angle compensation film on a plate or a polarizing plate, or a polarizing plate obtained by further laminating a brightness enhancement film on the polarizing plate is preferable.

  The optical film in which the optical layer is laminated on the polarizing plate can be formed by a method of laminating separately in the manufacturing process of a liquid crystal display device or the like. It is excellent in stability and assembly work, and has the advantage of improving the manufacturing process of a liquid crystal display device and the like. Appropriate bonding means such as an adhesive layer can be used for lamination. When adhering the above polarizing plate and other optical films, their optical axes can be set at an appropriate arrangement angle in accordance with the target retardation characteristics.

  An adhesive layer for adhering to other members such as a liquid crystal cell can be provided on the polarizing plate or the optical film in which at least one polarizing plate is laminated. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited. For example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is appropriately selected. Can be used. In particular, those having excellent optical transparency such as an acrylic pressure-sensitive adhesive, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and being excellent in weather resistance, heat resistance and the like can be preferably used.

  The pressure-sensitive adhesive layer can be provided on one side or both sides of a polarizing plate or an optical film as an overlapping layer of different compositions or types. Moreover, when providing in both surfaces, it can also be set as adhesive layers, such as a different composition, a kind, and thickness, in the front and back of a polarizing plate or an optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the purpose of use and adhesive force, and is generally 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

  The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing contamination until it is put into practical use. Thereby, it can prevent contacting an adhesion layer in the usual handling state. As the separator, except for the above thickness conditions, for example, an appropriate thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foamed sheet, metal foil, or a laminate thereof, or a silicone-based or long sheet as necessary. Appropriate ones according to the prior art, such as those coated with an appropriate release agent such as a chain alkyl type, fluorine type or molybdenum sulfide, can be used.

  The polarizing plate or the optical film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing plate or an optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses the polarizing plate or optical film by invention, and it can apply conventionally. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing plate or an optical film is arranged on one side or both sides of a liquid crystal cell, or a backlight or a reflecting plate used in an illumination system can be formed. In that case, the polarizing plate or optical film by this invention can be installed in the one side or both sides of a liquid crystal cell. When providing a polarizing plate or an optical film on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, a single layer or a suitable layer such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

<Tg: Glass transition temperature>
Tg was measured under the following measurement conditions using a TA Instruments dynamic viscoelasticity measuring device RSAIII.
Sample size: width 10mm, length 30mm,
Clamp distance 20mm,
Measurement mode: Tensile, Frequency: 1 Hz, Temperature rising rate: 5 ° C./min Dynamic viscoelasticity was measured and adopted as the temperature Tg of tan δ peak top.

<Polarizer X>
A polyvinyl alcohol film having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% and a thickness of 75 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, the film was dyed while being immersed in an aqueous solution of 0.3% concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) and stretched to 3.5 times. Then, it extended | stretched so that the total draw ratio might be 6 times in 65 degreeC borate ester aqueous solution. After extending | stretching, it dried for 3 minutes in 40 degreeC oven, and obtained PVA-type polarizer X (SP value 32.8, thickness 23 micrometers).

<Transparent protective film>
As a transparent protective film, a triacetyl cellulose film (TAC) (SP value 23.3) having a thickness of 80 μm was used without saponification / corona treatment (hereinafter, TAC not subjected to saponification / corona treatment). Is also referred to as “unprocessed TAC”).

<Active energy rays>
As an active energy ray, ultraviolet rays (gallium filled metal halide lamp) Irradiation device: Fusion UV Systems, Inc. Light HAMMER10 bulb: V bulb Peak illuminance: 1600 mW / cm ² , integrated irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm) )It was used. In addition, the illumination intensity of the ultraviolet-ray was measured using the Sola-Check system by Solatell.

(Adjustment of active energy ray-curable adhesive composition)
Examples 1-7, Comparative Examples 1-5
In accordance with the recipe shown in Table 2, the components were mixed and stirred at 50 ° C. for 1 hour to obtain active energy ray-curable adhesive compositions according to Examples 1 to 7 and Comparative Examples 1 to 5. Each component used is as follows.

(1) Radical polymerizable compound (A)
HEAA (hydroxyethyl acrylamide), SP value 29.6, homopolymer Tg 123 ° C, Kojin N-MAM-PC (N-methylolacrylamide), SP value 31.5, homopolymer Tg 150 ° C, Kasano Kosan (2) Radical polymerizable compound (B)
Aronix M-220 (tripropylene glycol diacrylate), SP value 19.0, homopolymer Tg 69 ° C., Toagosei Co., Ltd. light acrylate DCP-A (tricyclodecane dimethanol diacrylate), SP value 20.3, homo Polymer Tg 134 ° C., Kyoeisha Chemical Co., Ltd. (3) radical polymerizable compound (C)
ACMO (acryloylmorpholine), SP value 22.9, Tg of homopolymer 150 ° C., manufactured by Kojin Co., Ltd. Wasmer 2MA (N-methoxymethylacrylamide), SP value 22.9, Tg of homopolymer 99 ° C., manufactured by Kasano Kosan Co., Ltd. (4 ) Radical polymerizable compound (D)
4HBA (4-hydroxybutyl acrylate), SP value 23.8, homopolymer Tg-14 ° C., manufactured by Osaka Organic Chemical Industry Co., Ltd. (5) Photopolymerization initiator KAYACURE DETX-S (diethylthioxanthone), manufactured by Nippon Kayaku Co., Ltd. IRGACURE907 (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one), manufactured by BASF

  Next, the active energy ray-curable adhesive compositions according to Examples 1 to 7 and Comparative Examples 1 to 5 are coated on the transparent protective film with an MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, gravure roll). The number of lines was 1000 lines / inch, the rotation speed was 140% / vs line speed), and the thickness was 0.5 μm. Then, from the laminated transparent protective film side (both sides), it heated to 50 degreeC using IR heater, and irradiated the said ultraviolet-ray on both surfaces, and the active energy ray which concerns on Examples 1-7 and Comparative Examples 1-6 After the curable adhesive composition was cured, it was dried with hot air at 70 ° C. for 3 minutes to obtain a polarizing plate having transparent protective films on both sides of the polarizer. The line speed of bonding was 25 m / min. The adhesive strength (vs. TAC), water resistance (warm water immersion test), and durability (heat shock test) of each obtained polarizing plate were evaluated based on the following conditions.

Example 8
(Production of thin polarizing film Y and production of polarizing plate using it)
In order to produce the thin polarizing film Y, first, a laminated body in which a PVA layer having a thickness of 24 μm is formed on an amorphous PET base material is produced by air-assisted stretching at a stretching temperature of 130 ° C., and then, A colored laminate is produced by dyeing the stretched laminate, and the colored laminate is stretched integrally with the amorphous PET substrate so that the total stretch ratio is 5.94 times by stretching in boric acid water at a stretching temperature of 65 degrees. An optical film laminate comprising a 10 μm thick PVA layer was produced. The PVA molecules in the PVA layer formed on the amorphous PET substrate by such two-stage stretching are oriented in the higher order, and the iodine adsorbed by the dyeing is oriented in the one direction as the polyiodine ion complex. In addition, an optical film laminate including a PVA layer having a thickness of 10 μm constituting the high-functional polarizing film Y could be produced. Furthermore, the active energy ray-curable adhesive composition according to Example 1 was applied to the surface of the thin polarizing film Y of the optical film laminate, and the transparent protective film used in Example 1 was bonded from the adhesive application surface. Then, the amorphous PET base material was peeled off, and a polarizing plate using the thin polarizing film Y (polarizing plate according to Example 8) was produced.

<Adhesive strength>
The polarizing plate is cut into a size of 200 mm parallel to the stretching direction of the polarizer and 20 mm in the orthogonal direction, and between the transparent protective film (untreated TAC; SP value 23.3) and the polarizer (SP value 32.8). Was cut with a cutter knife, and the polarizing plate was bonded to a glass plate. With Tensilon, the protective film and the polarizer were peeled off at 90 ° direction at a peeling speed of 500 mm / min, and the peel strength was measured. Moreover, the infrared absorption spectrum of the peeling surface after peeling was measured by ATR method, and the peeling interface was evaluated based on the following reference | standard.
A: Cohesive fracture of protective film B: Interfacial delamination between protective film / adhesive layer C: Interfacial delamination between adhesive layer / polarizer D: Cohesive fracture of polarizer In the above criteria, A and D indicate that the adhesive strength is film This means that the adhesive strength is very excellent. On the other hand, B and C mean that the adhesive force at the interface of the protective film / adhesive layer (adhesive layer / polarizer) is insufficient (adhesive strength is poor). Taking these into consideration, the adhesive strength in the case of A or D is ○, A · B (“cohesive failure of protective film” and “interfacial peeling between protective film / adhesive layer” occur simultaneously) or A · C (Adhesive strength in the case of “cohesive failure of protective film” and “interfacial peeling between adhesive layer / polarizer” occur simultaneously) is Δ, and adhesive strength in the case of B or C is x.

<Water resistance (warm water immersion test)>
The polarizing plate was cut into a rectangle of 50 mm in the stretching direction of the polarizer and 25 mm in the vertical direction. After peeling this polarizing plate in 60 degreeC warm water for 6 hours, peeling between polarizer / transparent protective film was observed visually, and it evaluated based on the following reference | standard.
○: no peeling confirmed Δ: peeling occurred from the end portion, but no peeling of the central portion was confirmed ×: peeling occurred on the entire surface

<Durability (heat shock test)>
The pressure-sensitive adhesive layer was laminated on the acrylic film surface of the polarizing plate and cut into a rectangle of 200 mm in the stretching direction of the polarizer and 400 mm in the vertical direction. The polarizing plate was laminated on a glass plate, a heat cycle test at −40 ° C. to 85 ° C. was performed, the polarizing plate after 50 cycles was visually observed, and evaluated based on the following criteria.
○: No occurrence of cracks Δ: Cracks that do not penetrate in the stretching direction of the polarizer occurred (crack length 200 mm or less)
×: Cracks penetrating in the stretching direction of the polarizer occurred (crack length 200 mm)

  From the results shown in Table 3, the polarizing plate obtained by using the thin polarizing film Y having a thickness of 10 μm instead of the polarizer X having a thickness of 23 μm is good with respect to the TAC adhesive force, the hot water immersion test and the heat shock test. It can be seen that a good result is obtained.

Claims (6)

An active energy ray-curable adhesive composition containing a radical polymerizable compound on at least one surface of a polarizer (however, the glass transition temperature is from −80 ° C. to the main agent comprising a radical polymerizable compound and a cationic polymerizable compound) A transparent protective film was bonded via an adhesive layer formed by a cured layer of a radically polymerizable compound (a) that forms a homopolymer at 0 ° C. (excluding those containing 60 to 99.8% by mass) . A method of manufacturing a polarizing plate,
After applying the active energy ray-curable adhesive composition to the surface of the polarizer forming the adhesive layer and / or the surface of the transparent protective film forming the adhesive layer, the polarizer and the Bonding the transparent protective film, and then curing the active energy ray-curable adhesive composition by irradiation with active energy rays to form the adhesive layer,
The active energy ray has a ratio of the integrated illuminance in the wavelength range of 380 to 440 nm and the integrated illuminance in the wavelength range of 250 to 370 nm of 100: 0 to 100: 50.   The manufacturing method of the polarizing plate of Claim 1 which contains the said radically polymerizable compound 50weight% or more when it is set as 100 weight% of composition whole quantity.   The method for producing a polarizing plate according to claim 1, wherein the adhesive layer has a thickness of 0.01 to 7 μm.   The method for producing a polarizing plate according to any one of claims 1 to 3, wherein the active energy ray is obtained by blocking light having a short wavelength of 380 nm or less using a gallium lamp as a light source and using a band pass filter. The active energy ray-curable adhesive composition is a compound represented by the following general formula (1) as a photopolymerization initiator;

(Wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different). The manufacturing method of the polarizing plate of description. The active energy ray-curable adhesive composition is a compound represented by the following general formula (2) as a photopolymerization initiator;

Wherein R ³ , R ⁴ and R ⁵ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different. The manufacturing method of the polarizing plate in any one of Claims 1-5 to contain.