JP2009113123A - Cutting method of laminated optical film - Google Patents

Abstract

The present invention provides a method for cutting a laminated optical film capable of preventing the occurrence of cracks and delamination and ensuring the quality of a cut surface.
A method for cutting a laminated optical film laminated with an adhesive or an adhesive, wherein the laminated optical film (polarizing plate 1) is cut into a predetermined size by drawing with a cutting blade 3. Thereby, the cutting blade 3 can be slid and cut so that the laminated optical film (polarizing plate 1) is not crushed but is torn. It is possible to relieve the cutting stress acting on the cut surface, prevent the occurrence of cracks and delamination, and ensure the quality of the cut surface.
[Selection] Figure 1

Description

  The present invention relates to a cutting method for cutting a laminated optical film laminated via a pressure-sensitive adhesive or an adhesive.

  A polarizing plate is mentioned as an example of such a laminated optical film. The polarizing plate is used in many scenes as a constituent member of a liquid crystal display device (hereinafter, abbreviated as LCD), and in recent years, the demand for the polarizing plate is rapidly increasing. In addition, the use of high-value-added polarizing plates having an optical compensation function and a brightness enhancement function is increasing, and the demand for display quality tends to increase further.

  In general, the polarizing plate is cut from a long sheet-shaped raw material into a predetermined shape and size and mounted on an LCD panel. Conventionally, a vertical cutting method as shown in FIGS. 11 and 12 has been adopted for cutting the polarizing plate (see Patent Document 1 below). In this method, the angle of entry of the cutting blade 6 with respect to the surface of the polarizing plate 5 is used. Is 90 °. As the cutting blade 6, a Thomson blade having a predetermined frame shape can be used in addition to the single blade as illustrated.

  However, in the conventional cutting process, since the cutting edge 6 is pressed vertically against the surface of the polarizing plate 5 and the polarizing plate is crushed while being crushed, the cutting stress acting at the time of cutting causes cracks and delamination. There was a problem that the quality of the cut surface deteriorated. Here, delamination refers to a phenomenon in which an optical film laminated via a pressure-sensitive adhesive or adhesive partially peels off at the cut surface.

The following Patent Documents 2 to 4 describe a cutting method and a cutting device for paper, ceramic green sheets, etc., but suggest a solution for the cutting of laminated optical films such as polarizing plates. Not what you want.
JP 2002-219686 A Japanese Utility Model Publication No. 2-117893 Japanese Utility Model Publication No. 3-79428 JP-A-9-129502

  This invention is made | formed in view of the said situation, The objective is preventing the generation | occurrence | production of a crack and delamination, and providing the cutting method of the laminated optical film which can ensure the quality of a cut surface. .

  The above object can be achieved by the present invention as described below. That is, the method for cutting a laminated optical film according to the present invention is a method for cutting a laminated optical film laminated via an adhesive or an adhesive, and the laminated optical film is cut into a predetermined size by cutting with a cutting blade. It is characterized by cutting.

  According to the method for cutting a laminated optical film according to the present invention, since the laminated optical film is cut into a predetermined size by cutting with a cutting blade, the cutting blade is cut so as to cut the laminated optical film instead of crushing it. Can be slid and cut. Therefore, the cutting stress acting on the cut surface can be relaxed, the generation of cracks and delamination can be prevented, and the quality of the cut surface can be ensured.

  In the present invention, it is preferable that the angle of entry of the cutting blade with respect to the surface of the laminated optical film is greater than 0 ° and less than 90 ° during the cutting with the cutting blade. Thereby, the cutting stress which acts on a cut surface as mentioned above can be relieved, generation | occurrence | production of a crack and delamination can be prevented, and the quality of a cut surface can be ensured.

  Moreover, in this invention, it is more preferable that the approach angle of the said cutting blade with respect to the surface of the said laminated optical film exceeds 0 degree and becomes 40 degrees or less in the case of the drawing by the said cutting blade. As a result, the cutting stress acting on the cut surface can be more effectively relaxed, and in particular, the occurrence of delamination can be reliably prevented, and the quality of the cut surface can be sufficiently ensured.

  In the above, it is preferable that the cutting blade is constituted by a single blade and has a blade edge parallel to the surface of the laminated optical film. Since the cutting blade is composed of a single blade, the cutting can be performed easily and appropriately, and the sticking out of the cut surface of the adhesive or the adhesive can be suppressed. Further, since the cutting blade has a blade edge parallel to the surface of the laminated optical film, it is possible to avoid the cutting edge of the cutting blade from interfering with the pedestal on which the laminated optical film is placed in the cutting process.

  The present invention is also useful when the laminated optical film includes a polarizing plate in which a protective film is laminated on both sides of a polarizer via an adhesive. Here, “including a polarizing plate” means that the laminated optical film is a polarizing plate itself.

  When the protective film is an acrylic protective film, the occurrence of delamination due to cutting stress becomes significant, and the present invention having the above-described effects is particularly useful.

  In the case where a hard coat layer having a pencil hardness of 4H or more is formed on at least one surface of the polarizing plate, cracks due to cutting stress become prominent, and the present invention having the above-described effects is particularly useful. .

  Embodiments of the present invention will be described below. In this embodiment, an example of cutting a polarizing plate as a laminated optical film is shown. FIG. 1 is a perspective view schematically showing how a polarizing plate is cut by the cutting method of the present invention, and FIG. 2 is a side view thereof. In both figures, (a) shows the state before cutting, and (b) shows the state after cutting. FIG. 3 is a longitudinal sectional view of the polarizing plate.

  As shown in FIG. 3, the polarizing plate 1 is a laminated optical film in which a protective film 13 is laminated on both surfaces of a polarizer 11 via an adhesive. In this embodiment, a hard coat layer 14 is formed on the upper surface. . A detailed configuration of the polarizing plate 1 will be described later.

  As shown in FIGS. 1A and 2A, the polarizing plate 1 is placed on a pedestal 2 having a flat upper surface, and is transported to a predetermined cutting position and disposed below the cutting blade 3. Is done. The cutting blade 3 is constituted by a single blade extending linearly and has a cutting edge parallel to the surface of the polarizing plate 1. The cutting blade 3 is supported by a cutting device (not shown) in a state where the blade edge is directed to the surface of the polarizing plate 1.

  In the present embodiment, the polarizing plate 1 is directly placed on the pedestal 2, but a lower plate is interposed between the polarizing plate 1 and the pedestal 2 so as to prevent the cutting blade 3 from being worn or scratched. It may be. An example of the lower plate is a polystyrene sheet having a thickness of about 0.1 to 5 mm.

  When performing a cutting process on the polarizing plate 1, the polarizing plate 1 is transported to a predetermined cutting position by an operator or by a transport device provided around the base 2, and the cutting blade 3 is operated by operating the cutting device. Lower. At this time, as shown in FIGS. 1B and 2B, the polarizing plate 1 is cut into a predetermined size by the cutting blade 3. In the cutting process, the cutting blade 3 may be moved along the extending direction of the cutting edge in the process of lowering the cutting blade 3, and the function of moving the cutting blade 3 as such can be provided in the cutting device.

  According to the present invention, by cutting the polarizing plate 1 by cutting, the cutting blade 3 can be slid and cut so that the polarizing plate 1 is not crushed but is torn. Therefore, the cutting stress acting on the cut surface can be relaxed, the generation of cracks and delamination can be prevented, and the quality of the cut surface can be ensured.

  The entrance angle θ of the cutting blade 3 with respect to the surface of the polarizing plate 1 is preferably more than 0 ° and less than 90 °. Thereby, the cutting stress which acts on a cut surface is relieved, generation | occurrence | production of a crack and delamination can be prevented, and the quality of a cut surface can be ensured. Furthermore, in this invention, it is preferable that approach angle (theta) exceeds 0 degree and is 40 degrees or less. As a result, the cutting stress acting on the cut surface can be more effectively relaxed, and in particular, the occurrence of delamination can be reliably prevented, and the quality of the cut surface can be sufficiently ensured. In the present invention, the cutting blade 3 may be a round blade or the like, and the entry angle θ may be 0 °.

  In this embodiment, since the cutting blade 3 is constituted by a single blade, the cutting can be performed easily and appropriately, and from the cut surface of the adhesive or adhesive as compared with the case where a round blade is used. Can be suppressed. Further, since the cutting blade 3 has a cutting edge parallel to the surface of the polarizing plate 1, it is possible to avoid the cutting edge of the cutting blade 3 from interfering with the base 2 in the cutting process.

  As described above, the polarizing plate 1 of the present embodiment has a configuration in which the protective film 13 is laminated on both surfaces of the polarizer 11 via the adhesive, and the hard coat layer 14 is further provided.

  Although the thickness in particular of the polarizer 11 is not restrict | limited, About 5-80 micrometers is common. The polarizer 11 is manufactured by appropriately performing treatments such as swelling, dyeing, stretching, and crosslinking on a hydrophilic polymer. As the hydrophilic polymer, polyvinyl alcohol is generally used because of the good orientation of iodine or dichroic dye in the dyeing process, but is not particularly limited in the present invention. Specifically, for example, a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, a polyethylene terephthalate film, an ethylene vinyl acetate copolymer film, a polymer film such as a partially saponified film, a cellulose film, etc. Examples thereof include polyethylene-oriented films such as a dehydrated product of alcohol and a dehydrochlorination treatment of polyvinyl chloride.

  When the hydrophilic polymer is stretched, the total stretching ratio is preferably set in the range of 3 to 7 times, more preferably in the range of 4 to 6 times. This is because when the total draw ratio is less than 3 times, it is difficult to obtain a polarizing plate having a high degree of polarization, and when it exceeds 7 times, the film tends to be easily broken. Here, the hydrophilic polymer may be stretched gradually from 3 to 7 times in all steps such as swelling, dyeing, stretching, and crosslinking, and stretched only in any one step. Alternatively, it may be stretched a plurality of times in the same process.

  As a material for forming the protective film 13, a polymer film excellent in transparency, mechanical strength, thermal stability, isotropy, and the like is preferably used. Specifically, for example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), cellulose polymers such as diacetyl cellulose and triacetyl cellulose, and polyethers. Examples include sulfone polymers, polycarbonate polymers, polyamide polymers, polyimide polymers, polyolefin polymers, and acrylic polymers such as polymethyl methacrylate. 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 include polymer blends. Other examples include acrylic, urethane-based, acrylic-urethane-based, epoxy-based, and silicone-based thermosetting or ultraviolet curable resins.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing a non-substituted phenyl and a thermoplastic resin having a nitrile group. A specific example is 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 the protective film 13 can be determined as appropriate, it is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable. The transparent protective film is particularly suitable when the thickness is 5 to 150 μm.

  As the protective film 13 provided on both sides of the polarizer 11, a protective film made of the same polymer material may be used on the front and back sides, or a protective film made of a different polymer material or the like may be used.

  In the case where the protective film 13 is an acrylic protective film, the occurrence of delamination due to cutting stress becomes significant, so that the present invention having the above-described effects is particularly useful. Such an acrylic protective film contains an acrylic resin having a structural unit of an unsaturated carboxylic acid alkyl ester represented by the following general formula (1) and a structural unit of glutaric anhydride represented by the general formula (2) To do.

In general formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ² represents a hydrogen atom, an aliphatic group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon group.

In General Formula (2), R ³ and R ⁴ represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

  Examples of the acrylic resin include Japanese Patent Application Laid-Open Nos. 2004-70290, 2004-70296, 2004-163924, 2004-292812, 2005-314534, and 2006. No. 131898, JP 2006-206881 A, JP 2006-265532 A, JP 2006-283013 A, JP 2006-299005 A, JP 2006-335902 A, and the like. It is done.

  The content ratio of the structural unit represented by the general formula (1) in the acrylic resin is preferably 50 to 95 mol%, more preferably 55 to 90 mol%, still more preferably 60 to 85 mol%, particularly preferably. It is 65-80 mol%, Most preferably, it is 65-75 mol%. When the said content rate is less than 50 mol%, there exists a possibility that the effect expressed from the structural unit represented by General formula (1), for example, high heat resistance, and high transparency may not fully be exhibited. If the content is more than 95 mol%, the resin is brittle and easily cracked, and high mechanical strength cannot be fully exhibited, which may result in poor productivity.

  The content ratio of the structural unit represented by the general formula (2) in the acrylic resin is preferably 5 to 50 mol%, more preferably 10 to 45 mol%, still more preferably 15 to 40 mol%, particularly preferably. It is 20-35 mol%, Most preferably, it is 25-35 mol%. When the content is less than 5 mol%, the effects expressed from the structural unit represented by the general formula (2), for example, high optical properties, high mechanical strength, and excellent adhesion to the polarizer There is a possibility that the property and thickness reduction may not be sufficiently exhibited. When the said content rate is more than 50 mol%, there exists a possibility that high heat resistance and high transparency may not fully be exhibited, for example.

  The structural unit represented by the general formula (2) in the acrylic resin is preferably contained in the structural unit represented by the following general formula (3).

In General Formula (3), R ³ and R ⁴ represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

In general formulas (2) and (3), R ³ and R ⁴ are preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

  An acrylic resin having a structural unit of an unsaturated carboxylic acid alkyl ester represented by the general formula (1) and a structural unit of a glutaric anhydride represented by the general formula (2) is basically obtained by the following method. Can be manufactured.

  That is, the acrylic resin is obtained by copolymerizing an unsaturated carboxylic acid alkyl ester monomer corresponding to the structural unit represented by the general formula (1) and an unsaturated carboxylic acid monomer. After obtaining a), by heating the copolymer (a), the structural unit of the unsaturated carboxylic acid alkyl ester monomer in the copolymer (a) and the unsaturated carboxylic acid monomer It can be obtained by carrying out an intramolecular cyclization reaction of the structural unit and introducing the structural unit of glutaric anhydride represented by the general formula (2) into the copolymer.

Examples of the unsaturated carboxylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and t- (meth) acrylic acid. Butyl, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid Examples thereof include 3-hydroxypropyl, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate. Only 1 type may be used for these and 2 or more types may be used together. Among these, methyl (meth) acrylate is more preferable, and methyl methacrylate is particularly preferable in terms of excellent thermal stability. That is, in the general formula (1), it is particularly preferable that R ¹ is a methyl group and R ² is a methyl group.

  Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid, and the like. You may use the above together. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.

  Preferred examples of the intramolecular cyclization reaction include dealcoholization reaction and / or intramolecular cyclization reaction by dehydration. There are no particular restrictions on the method of heating and carrying out the intramolecular cyclization reaction, but the method of manufacturing by passing through a heated extruder having a vent, or in an apparatus that can be heated and degassed in a nitrogen stream or under vacuum. The method is preferred.

  In the production of the copolymer (a), the blending ratio of the monomers is preferably 15 to 45% by weight of the unsaturated carboxylic acid monomer, with the sum of the blended monomers being 100% by weight. Preferably it is 20-40 weight part. The unsaturated carboxylic acid alkyl ester monomer is preferably 55 to 85% by weight, more preferably 60 to 80% by weight. The content of the glutaric anhydride unit represented by the above general formula (3) when the copolymer (a) is heated by setting the content of the unsaturated carboxylic acid monomer to 15 to 45% by weight. Is within a preferable range of 20 to 40% by weight, and an acrylic resin excellent in heat resistance, colorless transparency, and retention stability can be obtained.

  In the said acrylic resin, other structural units other than the structural unit represented by General formula (1) and the structural unit represented by General formula (2) may be included.

  The acrylic resin can contain, for example, 0 to 10% by weight of a structural unit derived from an unsaturated carboxylic acid monomer that is not involved in the intramolecular cyclization reaction. As for the ratio of the structural unit derived from unsaturated carboxylic acid, 0 to 5 weight% is more preferable, and it is still more preferable that it is 0 to 1 weight%. By making the structural unit derived from the unsaturated carboxylic monomer in the acrylic resin 10% by weight or less, colorless transparency, retention stability, and moisture resistance can be maintained.

  The acrylic resin can contain other copolymerizable monomer units other than those described above. Examples of other vinyl monomers include acrylonitrile, methacrylonitrile, ethacrylonitrile, allyl glycidyl ether, maleic anhydride, itaconic anhydride, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, and acrylamide. , Methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate, N- Vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine, 2-isopropenyl-oxazoline, 2-vinyl Oxazoline, 2-acryloyl - oxazoline, N- phenylmaleimide, phenylaminoethyl methacrylate, styrene, alpha-methyl styrene, p- glycidyl styrene, p- aminostyrene, 2-styryl - and oxazoline and the like. These may be used alone or in combination of two or more.

  Among the other vinyl monomers, the content of styrene structural units such as styrene and α-methylstyrene is preferably 0 to 1% by weight, more preferably 0 to 0.1% by weight. . By setting the content concentration of the styrenic structural unit to 0 to 1% by weight, it is possible to prevent deterioration of retardation and deterioration of transparency.

  The acrylic resin preferably has a weight average molecular weight of 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, particularly preferably 50,000 to 500,000, and most preferably 60000 to 150,000. If the weight average molecular weight is out of the above range, the effects of the present invention may not be sufficiently exhibited.

  The acrylic resin has a Tg (glass transition temperature) of preferably 110 ° C. or higher, more preferably 115 ° C. or higher, still more preferably 120 ° C. or higher, particularly preferably 125 ° C. or higher, and most preferably 130 ° C. or higher. When Tg is 110 ° C. or higher, for example, when it is finally incorporated into a polarizing plate, it tends to be excellent in durability. The upper limit value of Tg of the acrylic resin is not particularly limited, but is preferably 300 ° C. or lower, more preferably 290 ° C. or lower, further preferably 285 ° C. or lower, particularly preferably 200 ° C. or lower, most preferably, from the viewpoint of moldability and the like. Is 160 ° C. or lower.

  The acrylic resin has a higher total light transmittance as measured by a method according to ASTM-D-1003 of a molded product obtained by injection molding, and is preferably higher, preferably 85% or more, more preferably 88%. More preferably, it is 90% or more. If the total light transmittance is less than 85%, the transparency is lowered, and there is a possibility that it cannot be used for the intended purpose.

  The content of the acrylic resin in the protective film 13 is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, still more preferably 70 to 100% by weight, and particularly preferably 80 to 100% by weight. When the content of the acrylic resin in the protective film is less than 50% by weight, the high heat resistance and high transparency inherent in the acrylic resin may not be sufficiently reflected.

  In the protective film 13, in addition to the acrylic resin, for example, acrylic elastic particles can be contained. As the acrylic elastic particles are dispersed in the protective film 13, excellent toughness as the protective film 13 can be obtained.

  The acrylic elastic particles preferably include a rubbery polymer. The rubbery polymer has, as a raw material monomer, an acrylic component such as ethyl acrylate and butyl acrylate as an essential component, and other components preferably contained as a silicone component such as dimethylsiloxane and phenylmethylsiloxane, styrene and α-methyl. Examples thereof include styrene components such as styrene, nitrile components such as acrylonitrile and methacrylonitrile, conjugated diene components such as butadiene and isoprene, urethane components, ethylene components, propylene components, and isobutene components. Among these, it is preferable to include at least one selected from an acrylic component, a silicone component, a styrene component, a nitrile component, and a conjugated diene component. The rubber polymer may contain a homopolymer of raw material monomers (preferably each of the above components), may contain a copolymer of two or more raw material monomers, or both of them. You can leave. More preferably, it is a rubbery polymer in which two or more of the above components are combined. For example, a rubbery polymer containing an acrylic component and a silicone component, a rubbery polymer containing an acrylic component and a styrene component, an acrylic component and a conjugate Examples thereof include a rubbery polymer containing a diene component, a rubbery polymer containing an acrylic component, a silicone component and a styrene component.

  The rubbery polymer preferably contains a crosslinkable component such as divinylbenzene, allyl acrylate, butylene glycol diacrylate in addition to the above components.

  The rubbery polymer preferably includes a polymer having a combination of an alkyl acrylate unit and an aromatic vinyl unit. Alkyl acrylate units, especially butyl acrylate, are extremely effective in improving toughness, and the refractive index of acrylic elastic particles can be adjusted by copolymerizing aromatic vinyl units such as styrene. Can do.

  The refractive index difference between the acrylic elastic particles and the acrylic resin is preferably 0.01 or less. This is because high transparency can be obtained in the protective film. As described above, any appropriate method can be adopted as a method for setting the difference in refractive index between the acrylic elastic particles and the acrylic resin to 0.01 or less. Examples thereof include a method for adjusting the composition ratio of each monomer unit constituting the acrylic resin, a method for adjusting the composition ratio of the rubbery polymer and each monomer contained in the acrylic elastic particles, and the like. In particular, an acrylic elastic particle having a small refractive index difference with an acrylic resin is obtained by copolymerizing an aromatic vinyl-based unit such as styrene with an alkyl acrylate such as butyl acrylate and adjusting the copolymerization ratio. be able to.

  The average particle diameter of the acrylic elastic particles is preferably 70 to 300 nm, more preferably 100 to 200 nm. If it is less than 70 nm, the effect of improving toughness may not be sufficient, and if it is more than 300 nm, the heat resistance may decrease.

  The content of the acrylic elastic particles in the protective film 13 is 40% by weight or less, preferably 7 to 40% by weight, more preferably 12% to 20% by weight. If the amount is less than 7% by weight, the toughness may not be sufficiently improved. If the amount exceeds 40% by weight, the heat resistance may be lowered.

  In the protective film 13, other heats such as polyethylene, polypropylene, polyamide, polyphenylene sulfide, polyether ether ketone, polyester, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyetherimide, etc. can be used together with the acrylic resin. Thermosetting resins such as plastic resins, phenol resins, melamine resins, polyester resins, silicone resins, and epoxy resins can be used. These are mix | blended in the range which does not impair the objective of this invention.

  Others, UV absorbers or antioxidants such as hindered phenols, benzotriazoles, benzophenones, benzoates, and cyanoacrylates, lubricants or plasticizers such as higher fatty acids, acid esters, acid amides, higher alcohols, Release agents such as montanic acid, its salts, its esters, its half esters, stearyl alcohol, stearamide and ethylene wax, anti-coloring agents such as phosphites and hypophosphites, halogen-based, phosphorus-based and silicone-based It may contain additives such as non-halogen flame retardants, nucleating agents, amine-based, sulfonic acid-based, polyether-based antistatic agents, pigments and other colorants. However, in light of the characteristics required by the application to be applied, it is preferable to add the protective film within a range where the transparency of the protective film does not deteriorate. The total content of these additives is preferably 10% by weight or less with respect to the protective film.

  In addition, the said acrylic elastic body particle | grains, other resin, and the said additive may be mix | blended with the raw material for forming the said acrylic resin, and may be mix | blended when manufacturing an acrylic resin, and after manufacturing an acrylic resin You may mix | blend.

  Examples of the acrylic resin used for the protective film 13 other than the above include (meth) acrylic resins having a lactone ring structure. Examples of the (meth) acrylic resin having a lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. Examples thereof include those described in Japanese Patent No. 146084 and Japanese Patent Application Laid-Open No. 2006-171464.

  Examples of the acrylic resin include JP 2006-309033 A, JP 2006-317560 A, JP 2006-328329 A, JP 2006-328334 A, JP 2006-337491 A, and JP 2006. -337374, JP-A-2006-337493, JP-A-2006-337569, and the like.

  The protective film 13 is laminated on both surfaces of the polarizer 11 via an adhesive, and an adhesive layer 12 is formed on both surfaces of the polarizer 11. Examples of the adhesive used for forming the adhesive layer 12 include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, and water-based polyesters. The said adhesive agent is normally used as an adhesive agent which consists of aqueous solution, and contains 0.5 to 60 weight% of solid content normally. In addition to the above, examples of the adhesive between the polarizer 11 and the transparent protective film 13 include an ultraviolet curable adhesive and an electron beam curable adhesive. The electron beam curable polarizing plate adhesive exhibits suitable adhesion to the various transparent protective films. In particular, it exhibits good adhesion even with respect to acrylic resins for which it was difficult to satisfy the adhesion. The adhesive used in the present invention can contain a metal compound filler.

  The protective film 13 may be subjected to a surface modification treatment before applying the adhesive. Specific examples of the treatment include corona treatment, plasma treatment, saponification treatment, and primer treatment. As the primer treatment, it is preferable to perform an undercoat treatment on the surface of the protective film 13 facing the adhesive layer 12 to form an easy-adhesion layer 15 (anchor layer) to improve the adhesion with the polarizer 11. Such undercoating is described in, for example, Japanese Patent Application Laid-Open No. 2007-140092.

  Examples of the easy adhesion layer 15 include a silicone layer having a reactive functional group. The material of the silicone layer having a reactive functional group is not particularly limited. For example, an isocyanate group-containing alkoxysilanol, an amino group-containing alkoxysilanol, a mercapto group-containing alkoxysilanol, a carboxy-containing alkoxysilanol, an epoxy group-containing Examples thereof include alkoxysilanols, vinyl-type unsaturated group-containing alkoxysilanols, halogen group-containing alkoxylanols, and isocyanate group-containing alkoxysilanols, and amino silanols are preferred. Furthermore, the adhesive force can be strengthened by adding a titanium-based catalyst or a tin-based catalyst for efficiently reacting the silanol. Moreover, you may add another additive to the silicone which has the said reactive functional group. Specifically, terpene resins, phenol resins, terpene-phenol resins, rosin resins, xylene resins and other tackifiers, UV absorbers, antioxidants, heat stabilizers and other stabilizers may be used.

  The silicone layer having the reactive functional group is formed by coating and drying by a known technique. The thickness of the silicone layer is preferably 1 to 100 nm, more preferably 10 to 80 nm after drying. During coating, silicone having a reactive functional group may be diluted with a solvent. The dilution solvent is not particularly limited, and examples thereof include alcohols. The dilution concentration is not particularly limited, but is preferably 1 to 5% by weight, more preferably 1 to 3% by weight.

  The surface of the protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, antisticking, diffusion or antiglare. In the present embodiment, an example in which the hard coat layer 14 is formed on the upper surface of the polarizing plate 1 is shown.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. In addition, the sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer (for example, a backlight-side diffusion plate).

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 20 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. When forming the surface fine uneven structure, the amount of fine particles used is generally about 2 to 70 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  In the case where the pencil hardness of the hard coat layer 14 is 4H or more, the occurrence of cracks due to cutting stress becomes significant, so that the present invention having the above-described effects is particularly useful. This pencil hardness is measured on the surface of the hard coat layer 14 in accordance with a pencil hardness test described in JIS K-5400 under a load of 500 g.

The hard coat layer 14 having a pencil hardness of 4H or more contains fine particles having a thickness in the range of 15 to 30 μm and a weight average particle size in the range of 30 to 75% of the thickness of the hard coat layer, and the surface is The average inclination angle θa of the concavo-convex shape is in the range of 0.4 to 1.5 degrees, and is formed using a hard coat layer forming resin containing the following components (A), (B), and (C). Can be mentioned.
(A) component: at least one of urethane acrylate and urethane methacrylate (B) component: at least one of polyol acrylate and polyol methacrylate (C) component: a polymer or copolymer formed from at least one of the following (C1) and (C2) Or mixed polymer (C1) of the above polymer and copolymer: alkyl acrylate having an alkyl group having at least one of hydroxyl group and acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one group of hydroxyl group and acryloyl group

  The component (B) preferably contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. This is because the hardness of the hard coat layer is further improved, the flexibility is maintained, and curling can be effectively prevented.

  An aspect in which an antireflection layer is formed on the hard coat layer may be employed. The antireflection layer preferably contains hollow and spherical silicon oxide ultrafine particles. Moreover, it is preferable that the glossiness by JISK7105 is the range of 50-95. The glossiness means the 60-degree specular glossiness of JISK7105 (1981 edition).

  The hard coat layer as described above is obtained by applying a hard coat layer forming material containing the hard coat layer forming resin, the fine particles, and a solvent to at least one surface of a substrate such as a protective film. Can be produced by forming a coating film and making the coating film effective. The solvent preferably includes ethyl acetate. This is because the adhesion between the hard coat layer and the substrate is improved and delamination can be prevented. The content ratio of ethyl acetate is preferably 20% by weight or more based on the entire solvent.

  The above hard coat layer is described in Japanese Patent Application No. 2007-078354 (not disclosed at the time of the present application) by the present applicant.

  In the above description, the most preferred embodiment of the present invention has been described. However, the present invention is not limited to this embodiment, and various modifications can be made within the scope substantially the same as the technical idea described in the claims of the present invention.

  The laminated optical film cut by the present invention is not limited to the polarizing plate as described above, and examples thereof include an optical film obtained by laminating the above polarizing plate 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. For example, a reflective polarizing plate or semi-transmissive polarizing plate obtained by further laminating a reflecting plate or a semi-transmissive reflecting plate on the polarizing plate of the present invention, or an elliptical polarizing plate or circularly polarizing plate obtained by further laminating a retardation plate on the polarizing plate. Examples thereof include a wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on a plate and a polarizing plate, and a polarizing plate in which a brightness enhancement film is further laminated on a polarizing plate.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbornene resin), or any of these binary, ternary copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystal polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. . Specific examples of the main chain type liquid crystal polymer include a nematic alignment polyester liquid crystal polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded at a spacer portion that imparts flexibility. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment-providing para-substitution through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogenic part composed of a cyclic compound unit. These liquid crystal polymers can be prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of liquid crystal layers and compensation of viewing angle, etc. It may be one in which retardation plates are stacked and optical characteristics such as retardation are controlled.

  Moreover, the laminated optical film cut | disconnected by this invention mentions what laminated | stacked the separator via the adhesion layer on one side of optical films, such as the said polarizing plate and retardation film, or these laminated bodies. In addition to being used for laminating the optical film, the adhesive layer is provided as an adhesive layer for adhering to other members such as a liquid crystal cell. 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.

  In addition to the above, in terms of prevention of foaming and peeling phenomena due to moisture absorption, deterioration of optical properties and liquid crystal cell warpage due to differences in thermal expansion, etc., as well as formability of liquid crystal display devices with high quality and excellent durability An adhesive layer having a low moisture absorption rate and excellent heat resistance is preferred.

  The adhesive layer is, for example, natural or synthetic resins, in particular, tackifier resins, fillers or pigments made of glass fibers, glass beads, metal powders, other inorganic powders, colorants, antioxidants, etc. It may contain an additive to be added to the adhesive layer. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient.

  The attachment of the adhesive layer to one side or both sides of an optical film such as a polarizing plate can be performed by an appropriate method. For example, a pressure sensitive adhesive solution of about 10 to 40% by weight in which a base polymer or a composition thereof is dissolved or dispersed in a solvent composed of a suitable solvent alone or a mixture such as toluene and ethyl acetate is prepared. A method in which it is directly attached on an optical film such as a polarizing plate by an appropriate development method such as a casting method or a coating method, or an adhesive layer is formed on a separator in accordance with the above, and this is applied to a polarizing plate or an optical film. The method of moving up is mentioned.

  The pressure-sensitive adhesive layer can also be provided on one side or both sides of an optical film such as a polarizing plate as a superposed layer of different compositions or types. Moreover, when providing in both surfaces, it can also be set as the adhesion layers of a different composition, a kind, thickness, etc. 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 40 μm, preferably 5 to 30 μm, particularly preferably 10 to 25 μm. If it is thinner than 1 μm, the durability will be poor, and if it is thicker than 40 μm, it will be liable to float or peel off due to foaming, resulting in poor appearance.

  On the exposed surface of the adhesive layer, a separator is temporarily attached and covered for the purpose of preventing contamination until it is put to 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, a suitable thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foam sheet, metal foil, laminate thereof, and the like, silicone type or Appropriate conventional ones such as those coated with an appropriate release agent such as long-chain alkyl, fluorine-based, or molybdenum sulfide can be used.

  In order to improve the adhesion between the optical film such as a polarizing plate and the pressure-sensitive adhesive layer, an anchor layer may be provided between the layers.

  As the material for forming the anchor layer, an anchor agent selected from polyurethane, polyester, and polymers containing an amino group in the molecule is preferably used, and polymers containing an amino group in the molecule are particularly preferred. . Polymers containing an amino group in the molecule ensure good adhesion because the amino group in the molecule exhibits an interaction such as a reaction or ionic interaction with the carboxyl group in the pressure-sensitive adhesive.

  In the present invention, the optical film such as the polarizing plate described above, and each layer such as the adhesive layer include, for example, salicylic acid ester compounds, benzophenol compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, etc. It may be one having a UV absorbing ability by a method such as a method of treating with a UV absorber.

  In order to specifically show the effect of the present invention, the polarizing plate cut by the method shown in FIGS. 11 and 12 (comparative example) and the polarizing plate cut by the method shown in FIGS. We compared the occurrence of delamination. As the polarizing plate, a polymethyl methacrylate (PMMA) film was used as a protective film, and a hard coat layer having a pencil hardness of 4H or more was formed on the upper surface of the protective film, and a thickness of 20 μm was adopted.

  In the comparative example, the approach angle of the cutting blade was 90 °, and the polarizing plate was cut while being crushed. Therefore, a crack with a length of 0.3 to 0.5 mm and a delamination with a width of 0.5 to 1 mm were formed on the cut surface. confirmed. FIG. 4 is a plan view photograph of the polarizing plate cut by the comparative example, and corresponds to the polarizing plate seen from above in FIG. The horizontal line confirmed at the location indicated by the arrow is the boundary between the polarizing plate and the pedestal on which the polarizing plate is placed. In a region D1 having a width of 0.5 to 1 mm from the cut surface, the layers are separated and air is infiltrated, and the occurrence of delamination can be confirmed.

  On the other hand, in the embodiment, the cutting blade has an approach angle of 1 °, and the cutting blade is slid and cut so that the polarizing plate is not crushed, but is cut. Only ~ 0.1 mm wide delamination was observed. FIG. 5 is a plan view photograph of the polarizing plate cut according to the example, and corresponds to the polarizing plate seen from above in FIG. In the examples, almost no delamination as in the comparative example was confirmed.

  6 to 10 are plan view photographs when the approach angle of the cutting blade is changed to 45 °, 40 °, 30 °, 20 °, and 10 °, respectively, in the examples. In the case of the approach angle of 45 ° shown in FIG. 6, occurrence of delamination is confirmed in the region D2 having a width of 0.3 mm from the cut surface. In the case of the approach angle of 40 ° shown in FIG. The occurrence of delamination was confirmed in the region D3 having a width of 0.17 mm from the above, but the occurrence of delamination was significantly suppressed as compared with the above comparative example. Moreover, generation | occurrence | production of delamination was not confirmed in the case of the approach angles 30 degrees, 20 degrees, and 10 degrees shown in FIGS. From this, in the present invention, it is understood that the angle of approach of the cutting blade is preferably 40 ° or less, and more preferably less than 40 °.

The perspective view which shows a mode that a polarizing plate is cut | disconnected by the cutting method of this invention roughly The side view which shows a mode that a polarizing plate is cut | disconnected by the cutting method of this invention roughly Vertical section of polarizing plate Plan view photograph of polarizing plate cut by comparative example Plan view photograph of polarizing plate cut according to Example Planar view of the polarizing plate when the angle of entry of the cutting blade is 45 ° Planar view of the polarizing plate when the angle of entry of the cutting blade is 40 ° Planar view of the polarizing plate when the angle of entry of the cutting blade is 30 ° Planar view of the polarizing plate when the angle of entry of the cutting blade is 20 ° Planar view of the polarizing plate when the angle of entry of the cutting blade is 10 ° The perspective view which shows a mode that a polarizing plate is cut | disconnected by the conventional cutting method roughly Side view schematically showing how a polarizing plate is cut by a conventional cutting method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polarizing plate 2 Base 3 Cutting blade 11 Polarizer 12 Adhesive layer 13 Protective film 14 Hard-coat layer 15 Easy-adhesion layer (theta) Approach angle of a cutting blade

Claims (7)

  A method for cutting a laminated optical film laminated via an adhesive or an adhesive, wherein the laminated optical film is cut into a predetermined size by drawing with a cutting blade.   2. The method for cutting a laminated optical film according to claim 1, wherein an angle of entry of the cutting blade with respect to the surface of the laminated optical film is more than 0 ° and less than 90 ° during the cutting with the cutting blade.   2. The method for cutting a laminated optical film according to claim 1, wherein an angle of approach of the cutting blade with respect to the surface of the laminated optical film is greater than 0 ° and equal to or less than 40 ° during the cutting with the cutting blade.   The method for cutting a laminated optical film according to any one of claims 1 to 3, wherein the cutting blade is constituted by a single blade and has a cutting edge parallel to the surface of the laminated optical film.   The method for cutting a laminated optical film according to claim 1, wherein the laminated optical film includes a polarizing plate in which a protective film is laminated on both surfaces of a polarizer via an adhesive.   The method for cutting a laminated optical film according to claim 5, wherein the protective film is an acrylic protective film.   The method for cutting a laminated optical film according to claim 5 or 6, wherein a hard coat layer having a pencil hardness of 4H or more is formed on at least one surface of the polarizing plate.

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