KR101102159B1 - Method for manufacturing polarizing plate - Google Patents

Abstract

A method of manufacturing a polarizing plate comprising both a laser light high absorptivity film and a low absorptivity film, which cuts the polarizing plate leaving only the release film layer of the surface bonded to the substrate, comprising a laser light low absorptivity film from an upper surface of the surface protection film layer. According to the manufacturing method of the polarizing plate which cut | disconnects the layer just before a layer with a laser, and then cut | disconnects the layer which consists of this laser beam low absorption rate film, and an adhesive layer with a cutter, The polarizer protective film layer which comprises a polarizing plate, There is no floating between the surface protection film layers, there is no contamination due to the sticking out of the pressure-sensitive adhesive on the cut surface, and a polarizing plate excellent in adhesion bonding to the substrate can be obtained.

Description

Manufacturing method of polarizing plate {METHOD FOR MANUFACTURING POLARIZING PLATE}

This invention relates to the manufacturing method of the polarizing plate used for image display apparatuses, such as a liquid crystal display device, and the polarizing plate cut | disconnected by the said method. Specifically, it relates to a manufacturing method of a polarizing plate including both a layer made of a laser light high absorption film and a layer made of a low absorption film and a polarizing plate cut by the method.

BACKGROUND ART Liquid crystal displays have been conventionally used in desk calculators, electronic clocks, and the like, but their applications are rapidly expanding in recent years. That is, liquid crystal displays have been used regardless of screen size from mobile devices such as mobile phones to large TVs. In addition to liquid crystal displays, organic electroluminescent (organic EL) displays also tend to increase, especially in mobile applications. For this reason, the polarizing plates used for these image display apparatuses are also increasing in demand, and performance suitable for each use is demanded.

The polarizing plate widely used in the above image display device is represented by a triacetyl cellulose film through a liquid adhesive layer on both sides of the polarizer layer 1 in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. It is manufactured by the structure which laminated | stacked the polarizer protective film layer. In this state or, if necessary, a liquid crystal cell or an organic EL in a form in which a function such as a circle / ellipse polarizing plate or a retardation plate having an optical characteristic, a surface reflection prevention / deflection, a light diffusing plate, a reflecting plate, or the like is added. It is bonded to image display elements, such as a display element, and becomes an image display apparatus. In addition, the polarizing plate has a polarizer protective film layer surface or a function-added film on the side of the bonding surface with the image display element for the purpose of preventing wound adhesion or contamination on the surface of the polarizer protective film layer or the surface of the function-added film layer until bonding to the image display element. The surface of the layer has a structure in which a surface protective film layer is bonded to the release film layer through the pressure-sensitive adhesive layer and the surface of the other polarizer protective film layer through the pressure-sensitive adhesive layer.

The layer structure of the above-mentioned polarizing plate used conventionally is shown as FIG. That is, as for the polarizing plate 12 shown in FIG. 4, the surface protection film layer 4, the adhesive layer 3, the polarizer protective film layer 2, the polarizer layer 1, the polarizer protective film layer 2a, a function addition film It consists of the layer 5, the adhesive layer 6, and the peeling film layer 7. In such a configuration, the function-added film layer is a film layer used arbitrarily and is not essential.

Moreover, in the image display apparatus for mobile uses, such as a mobile telephone, in recent years, thinning and thinning the whole module from the surface of a design or portability is advancing. Therefore, since further thin weight reduction is desired also about the polarizing plate which is an image display apparatus material, as shown in FIG. 1, the function addition film layer which also has the function of a polarizer protective film layer among the structures of the conventional polarizing plate shown in FIG. The use of the polarizing plate without the polarizer protective film layer 2a is also proposed by using.

That is, the strip-shaped polarizing plate shown in FIG. 1 has a surface protective film layer 4, an adhesive layer 3, a polarizer protective film layer 2, a polarizer layer 1, a function addition film layer 5, and an adhesive layer 6 ) And the release film layer 7. Cycloolefin type film is known as a film which adds such a function.

The polarizing plate is usually provided in the form of a roll of a strip-shaped film stretched in the long direction, and as a method of attaching the polarizing plate to the image display device or the like, the band-shaped polarizing plate is cut in advance in accordance with the size of the image display device such as a liquid crystal substrate. The polarizing plate pieces are bonded to one by one image display element. In such a method, when bonding a polarizing plate piece to an image display element, since it is necessary to transfer one piece of a polarizing plate piece immediately before bonding and peeling a peeling film from a polarizing plate piece, there is a limit also in shortening process time. have. Moreover, since a polarizing plate piece is normally punched out from a roll-shaped polarizing film, a dried wall is easy to generate | occur | produce, and workability | operativity at the time of transferring or conveying a polarizing plate piece is bad. Furthermore, in the case of using LCD as an image display device, the polarizing plate has a roll-shaped band-shaped polarizing plate in a 45 ° direction in advance with respect to the roll length direction in order to arrange the transmission axis of the polarizing plate by 45 ° with respect to the vertical or horizontal direction of the LCD screen. It needs to be punched out, and many parts which cannot be used near the end of a roll generate | occur | produce. In particular, when a large polarizing plate is used along with the large screen of the LCD, there is a problem that the gain is reduced. In addition, the cut end of the polarizing plate that has not been used for bonding has a problem that it is difficult to reuse because a plurality of materials are used in combination, resulting in increased waste.

As a means to solve this problem, when the stripped film in which the strip | belt-shaped film which the peeling film layer adhered on the strip | belt-shaped polarizing plate adhere | attached on the strip | belt-shaped polarizing plate orthogonally to the long direction progressed to the length corresponding to a board | substrate, Cutting means for cutting the strip-shaped film at least in the direction orthogonal to the longitudinal direction, leaving the release film layer, and separating the release film layer from the film piece cut by the cutting. A bonding means for bonding the release film separating means and the bonding surface of the film piece from which the release film layer has been separated to a corresponding position of the substrate so that the end face on the traveling direction side of the substrate that has been conveyed and the cut surface of the film piece become parallel. The polarizing plate bonding apparatus which bonds a polarizing plate to the board | substrate with which is equipped is disclosed (for example, JP2005-37416-A).

According to this method or the like, the polarizing plate can be automatically bonded to the image display element continuously, there is no need of the cut polarizing plate transfer material, and since the release film layer is not cut, it can be bonded at high speed and becomes unnecessary. This is how the cut piece does not come out. And in this method, making a strip | belt-shaped polarizing plate cut | disconnects only a peeling film layer, and cut | disconnects a polarizing plate (henceforth a half cut) makes it an essential requirement. As a cutting means, a cutter cutter, a cylinder for driving the cutter blade, and a bottom dead center position adjusting member for adjusting the bottom dead center position of the cutter blade are provided by using a crush cutter and a dicing cutter. It is known to carry out. However, when cutting by cutter blade, the cutting edge is beautiful when the cutting edge angle is sharp, but when the cutting edge of the cutter is short and the angle of cutting edge is obtuse, the adhesive or adhesive sticks out from the cutting edge, Problems such as staining, and the degree of the difference is caused by the angle of the cutter blade to be used, but when the cutter is used, the surface protection film layer on the polarizer protective film layer constituting the polarizing plate on the cutting surface of the polarizing plate is excited. This deterioration has a drawback of adversely affecting the physical properties of the polarizing plate.

In the conventional method of cutting a strip | belt-shaped polarizing plate in accordance with the magnitude | size of an image display element, such as a liquid crystal substrate previously, and bonding a polarizing plate piece to a piece of image display element, the problem which arises by the cutting method by said cutter blade, That is, for the protruding of the adhesive or the adhesive, and further, the peeling of the surface protective film layer on the polarizer protective film layer, after cutting the polarizer layer cut end surface in advance, the defect portion can be removed and then bonded to the image display element. . However, in the said half cut system, since it is difficult to process a cut surface beforehand in a continuous process, the cutting method without such a fault is needed.

On the other hand, the method of cutting | disconnecting a strip | belt-shaped polarizing plate using a laser is also known. For example, JP2008-284572-A describes that a band-shaped polarizing plate can be cut by irradiating a laser beam. Specifically, a pair of triacetyl cellulose (TAC) film layers are bonded to both sides of the polyvinyl alcohol (PVA) film layer, and on one side of the TAC film layer as a polyethylene terephthalate (PET) film through an acrylic pressure-sensitive adhesive layer. The formed separator is provided, and the strip-shaped polarizing plate provided with the surface protection film layer which consists of PET films on the other TAC film layer side is cut | disconnected by irradiating a laser beam.

The strip-shaped polarizing plate to be cut in JP2008-284572-A is a film having a high average absorption of laser light in the oscillation wavelength range of irradiated laser light such as PVA film, TAC film and PET film (hereinafter referred to as `` laser light high absorption rate film ''). For example), for example, a film having a higher average absorptivity than 2% is laminated. The laminated polarizing plate made of such a laser light high absorptivity film can be satisfactorily cut without deforming the cut surface of the polarizing plate by a conventional method as shown in JP2008-284572-A.

However, in the method shown in JP2008-284572-A, in addition to the laser light high absorption rate film, the average absorption rate of the laser light in the oscillation wavelength range of the laser light irradiated, such as a cycloolefin polymer film, a polypropylene film, and a polymethyl methacrylate film, When cutting a strip-shaped polarizing plate including a low film (hereinafter sometimes referred to as a "laser light low absorptivity film"), for example, a film having an average absorptivity of 2% or less, the output of the laser light is small. Although the layer which consists of a laser beam high absorptivity film of a strip | belt-shaped polarizing plate can be cut | disconnected, the layer which consists of a laser beam low absorptivity film cannot be cut | disconnected. On the other hand, when the output of a laser beam is enlarged, it is possible to cut not only the layer which consists of a laser beam high absorptivity film of a strip-shaped polarizing plate, but also the layer which consists of a laser beam low absorptivity film. However, in this case, since excessive heat is applied to the layer made of the laser light high absorptivity film, the end of the cut polarizing plate melts and the cut end deforms (see FIG. 6). The cross-sectional quality of a polarizing plate whose shape of the cut surface is deformed is deteriorated. Furthermore, various problems may arise by the fall of the said cross-sectional quality. For example, when adhesiveness is bonded to a glass substrate, high adhesiveness is calculated | required. However, there arises a problem such as bubbles getting into the bonding surface with the glass substrate due to the unevenness of the cut surface of the polarizing plate.

In addition, in the band-shaped polarizing plate comprising a layer made of a laser light low absorptivity film, when cutting the layer made of a laser light low absorptivity film by increasing the output of the laser light, Since the release film layer is usually composed of a laser light high absorption rate film, the release film layer is cut before the laser light low absorption rate film is melt-cut. For this reason, the application of the laser method is considered extremely difficult in the so-called half-cut type cutting method in which it is necessary to cut all the film layers constituting the other polarizing plate leaving only the release film layer.

For this reason, the present inventors have provided both the layer which consists of a laser beam high absorptivity film, and the layer which consists of a laser beam low absorptivity film, and the strip | belt-shaped polarizing plate which consists of a peeling film layer which consists of a laser beam high absorptivity film, and only the peeling film layer In the manufacturing method of the polarizing plate which cut | disconnects the film layer and adhesive layer which comprise the other polarizing plate left behind, there is no substantial lifting between the polarizer protective film layer and surface protective film layer which comprise a polarizing plate after cutting | disconnection, In order to complete the present invention, as a result of studying the method of cutting the film layer and the pressure-sensitive adhesive layer constituting the other polarizing plate without leaving out the cutting edge and the long life of the cutter blade and leaving only the peeling film accurately, Reached.

The present invention includes the following.

[1] A polarizer protective film layer made of a laser light super absorbency film is laminated on one side of a polarizer layer made of a polyvinyl alcohol-based resin film, and a laser beam is formed on the surface opposite to the polarizer layer of the polarizer protective film through an adhesive layer. A surface protective film layer made of a high absorptivity film is laminated, and on the other side of the polarizer layer on the opposite side to the polarizer layer of the layer made of the laser light low absorptivity film and the layer made of the laser light low absorptivity film through an adhesive layer. A method for producing a polarizing plate comprising cutting a layer of a strip-shaped polarizing plate in which a release film layer made of a laser light high absorption film is laminated via an adhesive layer, leaving only the release film, and cutting the layers constituting another polarizing plate, from a surface protective film layer. Laser cutting up to the layer immediately preceding the layer made of the laser light low absorption rate film And then cutting the layer and the pressure-sensitive adhesive layer made of the laser light low absorption rate film with a cutter.

[2] The method according to [1], wherein the laser light low absorptivity film is a film having an average absorptivity of laser light of 2% or less, and the laser light high absorptivity film is a film having an average absorptivity of laser light of more than 2%.

[3] The method according to [2], wherein the laser light low absorptivity film is a film having an average absorptivity of laser light of 1% or less.

[4] The method according to any one of [1] to [3], having a polarizer protective film layer made of a laser light high absorptivity film between the layer made of the polarizer layer and the laser light low absorptivity film.

[5] The method according to any one of [1] to [4], wherein the laser light low absorption rate film is a cycloolefin polymer film, a polypropylene film, or a polymethyl methacrylate film.

[6] The method according to any one of [1] to [5], wherein the laser is a carbon dioxide gas laser.

[7] A polarizing plate produced by the method according to any one of [1] to [6].

According to the manufacturing method of the polarizing plate of this invention, when a band-shaped polarizing plate is employ | adopted the so-called half-cut system which cut | maintains only a peeling film, and cut | disconnects a band-shaped polarizing plate in the case where both a laser beam high absorption rate film and a low absorption rate film are included in a polarizing plate, The surface protection film layer on the polarizer protective film layer constituting the polarizing plate at the cut surface of the polarizing plate after the treatment is substantially free of the lifting, there is no bleeding of the adhesive on the cutting surface, and the surface protective film layer and the polarizer layer leaving the release film layer accurately. Since the layer which consists of a laser beam low absorption rate film can be cut | disconnected, and it uses together with a laser, it has the effect that the lifetime of the cutter blade used for cutting also becomes long.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of the laminated constitution of the lightweight strip | belt-shaped polarizing plate applied to this invention.
It is a cross-sectional schematic diagram which shows an example of the laminated constitution of the strip | belt-shaped polarizing plate applied to this invention.
3 is a schematic cross-sectional view by two-stage cutting of the present invention.
It is a cross-sectional schematic diagram which shows an example of the laminated constitution of the polarizing plate applied by the conventional method.
5 is a micrograph of a cut surface of a polarizing plate cut by the method of the present invention obtained in Example 1. FIG.
6 is a micrograph of a cut surface of a polarizing plate cut using only a fixed ring phosphorus.
7 is a micrograph of the fixed ring phosphorus after cutting of the polarizing plate used in Comparative Example 1. FIG.
8 is a micrograph of a fixed ring phosphorus after cutting of a polarizing plate used in Comparative Example 1. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail, referring an accompanying drawing suitably. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows the example of the laminated constitution of the strip | belt-shaped polarizing plate used for the manufacturing method of the polarizing plate of this invention. In FIG. 1, the strip-shaped polarizing plate is formed on one side of the polarizer layer 1 on an opposite side (upper surface) of the polarizer protective film layer 2 and the polarizer layer of the polarizer protective film layer 2 through an adhesive layer (not shown). The layer of the surface protection film layer 4 which consists of the laser beam low absorptivity film which also has a polarizer protection function and phase difference function through the adhesive bond layer (not shown) on the other surface of the polarizer layer 1 via the adhesive layer 3 (5), the adhesive layer 6 and the peeling film layer 7 are laminated | stacked in this order. It is a cross-sectional schematic diagram which shows the example of the laminated constitution of the other strip | belt-shaped polarizing plate used for the manufacturing method of the polarizing plate of this invention. In FIG. 2, the band-shaped polarizing plate is provided on one side of the polarizer layer 1 on an opposite side (upper surface) of the polarizer protective film layer 2 and the polarizer layer of the polarizer protective film layer 2 through an adhesive layer (not shown). The surface protective film layer 4 via the adhesive layer 3 has a polarizer protective film layer 2a and an adhesive layer (not shown) on the other side of the polarizer layer 1 through an adhesive layer (not shown). The layer (5), the pressure-sensitive adhesive layer (6), and the release film layer (7) made of a laser light low absorptivity film having a phase difference capability are laminated in this order.

In the practice of the present invention, the strip-shaped polarizing plate is provided in the form of a roll-shaped film usually stretched in a long direction, and after cutting the strip-shaped polarizing plate leaving only the release film layer 7 in accordance with the size of the image display element in advance. The peeling film layer is peeled off from the polarizing plate, and a polarizing plate piece is laminated | stacked on one by one image display element, and is used. However, as a means for cutting a polarizing plate to the size of a desired image display element leaving only a peeling film layer from a strip | belt-shaped film, in the case of the strip | belt-shaped polarizing plate shown in FIG. 1, the surface protection film layer 4 of the uppermost surface, and the adhesive layer 3 ), The polarizer protective film layer 2, the polarizer layer 1, the adhesive layer (not shown), or the band-shaped polarizing plate shown in FIG. 2, the surface protective film layer 4 and the adhesive layer 3 of the uppermost surface. , The polarizer protective film layer 2, the polarizer layer 1, the polarizer protective film layer 2a, and the adhesive layer (not shown) were cut by a laser, and then the layer 5 made of a laser light low absorption rate film and an adhesive The layer 6 is cut with a cutter.

The polarizer layer 1 used by this invention is a film which has a function which takes out linearly polarized light from incident natural light, and can use the polarizing film by which the dichroic dye was adsorption-oriented to the polyvinyl alcohol-type resin film. The average absorption of the laser beam of the film is greater than 2%, for example, about 6%. Polyvinyl alcohol-type resin which comprises the polarizer layer 1 can be obtained by saponifying polyvinyl acetate type resin. As polyvinyl acetate type resin, the copolymer etc. of vinyl acetate and the other monomer copolymerizable with this besides the polyvinyl acetate which is a homopolymer of vinyl acetate are illustrated. As another monomer copolymerized with vinyl acetate, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamide which has an ammonium group, etc. are mentioned, for example. Saponification degree of polyvinyl alcohol-type resin is about 85-100 mol% normally, Preferably it is 98 mol% or more. The polyvinyl alcohol-based resin may be further modified. For example, polyvinyl formal and polyvinyl acetal modified with aldehydes can also be used. Moreover, the polymerization degree of polyvinyl alcohol-type resin is about 1,000-10,000 normally, Preferably it is about 1,500-5,000.

What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of the polarizer layer 1. The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, It can form into a film by a well-known method. Although the film thickness of the raw film which consists of polyvinyl alcohol-type resin is not specifically limited, For example, it is about 1-150 micrometers. In consideration of ease of stretching and the like, the film thickness is preferably 10 µm or more.

The polarizer layer 1 is a step of uniaxially stretching such a polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, and a polychromatic adsorbed dichroic dye. It is manufactured through the process of processing a vinyl alcohol-type resin film with the boric acid aqueous solution, and the process of washing | cleaning after the process by this boric acid aqueous solution. As a dichroic dye, iodine or a dichroic organic dye is used.

The polarizer protective film layers 2 and 2a used in this invention consist of a laser beam high absorption rate film, and the average absorption of a laser beam is usually larger than 2%, and can be comprised with a suitable transparent film. Especially, the film which consists of resin which is excellent in transparency, the uniformity of an optical characteristic, mechanical strength, thermal stability, etc. is used preferably. For example, a cellulose resin film such as triacetyl cellulose or diacetyl cellulose, a polyester resin film such as polyethylene terephthalate or polyethylene isophthalate, polybutylene terephthalate, a polycarbonate resin film, a polyether sulfone resin A film, a polysulfone resin film, a polyimide resin film, etc. are mentioned. Lamination of the transparent protective film layers 2 and 2a to the polarizer layer 1 is carried out through an adhesive layer, and an adhesive known in the art may be used, which is known in the oscillation wavelength range of the irradiated laser light. The average absorption of laser light is high and is usually larger than 2%.

Examples of such an adhesive include an aqueous solvent adhesive, an organic solvent adhesive, a hot melt adhesive, a solvent-free adhesive, and the like. More specifically, examples of the aqueous solvent adhesive include a polyvinyl alcohol-based resin solution, an aqueous two-component urethane emulsion adhesive, and the organic solvent adhesive, for example, a two-component urethane adhesive. Examples thereof include one-component urethane adhesives and the like. When using the acetyl cellulose type film hydrophilized by the saponification process etc. for the adhesive surface with a polarizer as a polarizer protective film, the polyvinyl alcohol-type resin aqueous solution is used suitably as an adhesive agent. The polyvinyl alcohol-based resin used as an adhesive includes a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate which is a homopolymer of vinyl acetate, and a vinyl alcohol copolymer obtained by saponifying a copolymer of vinyl acetate and other monomers copolymerizable therewith, Furthermore, there exist a modified polyvinyl alcohol polymer etc. which partially modified | denatured these hydroxyl groups. You may use a polyhydric aldehyde, a water-soluble epoxy compound, a melamine type compound, etc. as an additive for this adhesive agent.

The polarizing plate in this invention uses a laser beam low absorption rate film as a constituent layer material of this polarizing plate. The average absorption of the laser beam in the oscillation wavelength range of the irradiated laser beam is usually 2% or less, preferably 1% or less. In this specification, "the average absorption rate (%) of the laser beam in the oscillation wavelength range of the irradiated laser beam" can be measured using the conventionally well-known ATR (Attenuated total reflection) method. The said "ATR method" is a method of obtaining the absorption spectrum in the surface of a measurement object by irradiating light (laser light) which has arbitrary wavelength with respect to a measurement object, and measuring the light totally reflected on the surface of a measurement object. The average absorption rate of the laser light in the oscillation wavelength range of the irradiated laser light is measured by measuring the absorbance of light having an arbitrary wavelength within the oscillation wavelength range of the irradiated laser light by using the ATR method and calculating the average value of the obtained absorption rate. Can be obtained.

As such a laser light low absorption rate film, an cyclic olefin resin film containing an acrylic resin film such as polymethyl (meth) acrylate or polyethyl (meth) acrylate, a polyolefin resin film, or a cyclic olefin such as norbornene as a monomer More specifically, a cycloolefin polymer (COP) film, a polypropylene (PP) film, a polymethyl methacrylate (PMMA) film, etc. are mentioned. Since these films have not only the retardation film function required for a polarizing plate but also the outstanding water absorption prevention function and moisture resistance prevention function, it can also be used by switching to polarizer protective films, such as TAC, like the strip-shaped polarizing plate shown in FIG.

Moreover, the polarizing plate in this invention is a surface protection film layer and a laser beam low absorption rate according to the objective for the functional additional film layers, such as a phase difference film layer, a viewing angle expansion film layer, an antireflection film layer, an antiglare film layer, and a reflection film layer. You may further have it in any one of the layers which consist of films, and this function addition film layer is comprised from the laser beam high absorption rate film. Moreover, you may use these as one layer or multiple layers.

In the present invention, a pressure-sensitive adhesive known in the art may be used for the pressure-sensitive adhesive used for the pressure-sensitive adhesive layers 3 and 6 forming the polarizing plates. The known adhesive has a high average absorption of the laser light in the oscillation wavelength range of the laser light to be irradiated, and is usually larger than 2%. For example, those having a base polymer such as acrylic, rubber, urethane, silicone, or polyvinyl ether are used. Moreover, an energy ray hardening type, a thermosetting type, etc. may be sufficient. Among these, the adhesive which used acrylic resin excellent in transparency, weather resistance, heat resistance, etc. as a base polymer is suitable.

Although it does not specifically limit as an acrylic adhesive, (meth) acrylic-ester base polymers, such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, or these ( The copolymer base polymer which used two or more types of meta) acrylic acid ester etc. is used suitably. In addition, polar monomers are copolymerized in these base polymers. As a polar monomer, for example, (meth) acrylic acid, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 2-hydroxyethyl, (meth) acrylamide, 2-N, N-dimethylaminoethyl (meth) The monomer which has a carboxy group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc. like acrylate and glycidyl (meth) acrylate is mentioned.

These acrylic adhesives can of course be used alone, but a crosslinking agent is usually used in combination. As a crosslinking agent, forming a carboxylic acid metal salt between a carboxyl group as a divalent or polyvalent metal ion, forming an amide bond between a carboxyl group as a polyamine compound, ester between a carboxyl group as a polyepoxy compound or a polyol compound Forming a bond, forming an amide bond between a carboxyl group as a polyisocyanate compound, etc. are illustrated. Especially, a polyisocyanate compound is used widely as an organic type crosslinking agent.

The energy ray-curable pressure-sensitive adhesive has a property of being cured by irradiation with energy rays such as ultraviolet rays or electron beams, has adhesiveness even before energy ray irradiation, adheres to adherends such as films, and cures by energy ray irradiation to adjust the adhesion. It is an adhesive which has the property to be able to do it. In addition, in this invention, when a curable adhesive is used for an adhesive layer, an adhesive layer means the layer which consists of hardened | cured material of a curable adhesive. It is particularly preferable to use an ultraviolet curable pressure sensitive adhesive as the energy ray curable pressure sensitive adhesive. An energy radiation curable pressure sensitive adhesive generally consists of an acrylic pressure sensitive adhesive and an energy radiation polymerizable compound as main components. Usually, a crosslinking agent is further mix | blended, and also a photoinitiator, a photosensitizer, etc. can also be mix | blended as needed.

In addition to the base polymer and the crosslinking agent, in order to adjust the adhesive force, cohesion force, viscosity, elastic modulus, glass transition temperature and the like of the pressure-sensitive adhesive, the pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer is, for example, resins that are natural or synthetic materials, and adhesiveness. Appropriate additives, such as a provision resin, antioxidant, dye, a pigment, an antifoamer, a caustic agent, a photoinitiator, can also be mix | blended. Moreover, it can also be set as the adhesive layer which contains microparticles | fine-particles and shows light-scattering property. Moreover, antioxidant, a ultraviolet absorber, etc. may be mix | blended with an adhesive layer. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex salt compounds and the like.

The peeling film layer 7 which comprises a polarizing plate in this invention is a peeling material which consists of a laser beam high absorptivity film, Comprising: The average absorptivity of the laser beam in the oscillation wavelength range of a laser beam irradiated consists of a film which is usually larger than 2%. The usual release material used for an optical film, for example, a polyethylene terephthalate film, a polyester film, etc. are used.

Moreover, the board | substrate 8 of the display apparatus which bonds a polarizing plate after peeling the peeling film layer 7 is used for flat upper materials, such as glass substrates and synthetic resin substrates used for display apparatuses, such as a liquid crystal display device and a plasma display device. It may be a substrate on which a component part such as a liquid crystal cell and an electrode is formed in advance. As the shape of the substrate, shapes such as square and rectangle are generally used.

As the laser device used for cutting the band-shaped polarizing plate in the present invention, it is possible to use a conventionally known infrared laser, for example, a carbon dioxide laser, a YAG laser, a UV laser, etc., but there is little cleavage and unevenness of the cutting surface, Application of the carbon dioxide gas laser is recommended from the point of view.

Although the cutting speed by a laser depends on the thickness of the strip | belt-shaped polarizing plate to cut, if it is the range of 70-500 micrometers in thickness, it is 1 m / min or more, Preferably it is 5-60 m / min. If the cutting speed is less than 1 m / min, the productivity tends to be inferior. Moreover, although the output of an infrared laser is based also on thickness of a polarizer, desired cutting speed, etc., it is normally used within the range of 10W-400W. The laser wavelength used in this invention is a laser wavelength of 9.4 micrometers in the cutting process of the polarizing plate which consists of a layer which consists of a laser beam low absorptivity film irradiated only to one surface of the polarizer which this invention targets, especially a thin band-shaped polarizing plate. It is recommended to use one. In the case of cutting using such a laser wavelength, for example, the cut section is beautiful as compared with cutting using a laser wavelength of 10.6 µm.

Cutting with such a laser is performed from the surface protection film layer which comprises a strip | belt-shaped polarizing plate as shown in FIG. 3 to the layer immediately before the layer 5 which consists of a laser beam low absorption rate film. When this cutting is cut to the layer 5 made of the laser light low absorptivity film and the pressure-sensitive adhesive layer 6, leaving only the release film layer 7, the layer 5 made of the laser light low absorptivity film has low light absorption capability. Therefore, cutting (adjustment of depth of cut) with good dimensional accuracy with a laser is difficult, and in most cases, a release film is also cut and a desired half cut is difficult. Moreover, even if it could be half-cut, since the resin melted and became agglomerated state, even if the peeling film layer 7 was peeled off from the polarizing plate after cutting and bonded to the substrate 8, the bonding part of the substrate and the polarizing plate was raised and uniformly adhered evenly. Can not.

This invention cuts the strip | belt-shaped polarizing plate which cut | disconnected the layer just before the layer 5 which consists of such a laser beam low absorptivity film with a laser, leaving the peeling film layer 7 next using a cutter. By adopting such a method, it is possible to improve the production cost resulting from the lifting of the surface protection film 4 and the sticking out of the adhesive, which are generated when cutting all the strip-shaped polarizing plates with the cutter, and furthermore, resulting in a significantly short cutter life. When the strip-shaped polarizing plate is cut only with a laser, a complicated and high-tech work that requires cutting only the release film layer from a polarizing plate laminated with a protective film layer or a peeling film layer that differs significantly in light absorption capability, This is solved by employing an extremely simple method of performing the cutting operation in two stages.

The cutter for cutting the layer 5 and the pressure-sensitive adhesive layer made of the laser light low absorption rate film may be a cutter commonly used in the field of optical films, for example, a piezoelectric cutter, a dicing cutter, a fixed ring seal, a rotary ring seal, or the like. Can be mentioned. The use of these cutter blades provided with the bottom dead center position adjustment member which adjusts the bottom dead center position of the cylinder which drives a cutter blade, or a cutter blade is recommended. In this case, by adjusting the bottom dead center position to 0.5 times or less of the thickness of the release film layer 7, only the layer 5 and the pressure-sensitive adhesive layer made of the laser light low absorptivity film are left in the film long direction, leaving the release film 7 accurately. It can cut in the direction orthogonal to the.

Moreover, although the average absorption of the typical film applied to the polarizing plate in the range (9.2 micrometers-10.8 micrometers) of the emission wavelength of a carbon dioxide laser was measured, the triacetyl cellulose film (TAC film): 13%, polyvinyl alcohol (PVA film) ): 6%, polyethylene terephthalate film (PET film): 8%, cycloolefin polymer film (COP film): 0.3%, polymethyl methacrylate film (PMMA film): 0.8%, polypropylene film (PP film) : 0.7%.

The polarizing plate cut | disconnected to the desired shape by the above-mentioned this invention method is bonded together on board | substrates 8, such as a liquid crystal display, after the peeling film layer 7 peels off. These operations recommend the strip-shaped film laminated | stacked on the structure shown in FIG. 1 or 2 in roll shape, pull out this roll-shaped film in the long direction, and orthogonal to the long direction. Cutting process of cutting the said strip | belt-shaped film in the direction orthogonal to a longitudinal direction at least the said strip | belt-shaped film, leaving the said peeling film layer, when this cutting surface advanced to the length corresponding to a board | substrate, by this cutting As a polarizing plate bonding apparatus which continuously bonds a polarizing plate to the board | substrate provided with the separation process which isolate | separates the said peeling film layer from the cut film piece, and the bonding process which bonds the adhesive surface of the said film piece from which the peeling film layer was isolate | separated to the conveyed board | substrate. It is recommended to apply.

Example

EMBODIMENT OF THE INVENTION Hereinafter, the method of this invention is demonstrated in detail based on an Example.

[Production of Polarizing Plate]

In the present Example, the strip | belt-shaped polarizing plate used the thing of the structure shown substantially in FIG. That is, the polarizer protective film layer 2 made of a triacetyl cellulose film having a thickness of 80 μm is formed on both surfaces of the polarizer layer 1 made of a film having a thickness of 25 μm with iodine adsorbed onto polyvinyl alcohol. An acrylic pressure-sensitive adhesive having a thickness of 20 μm for the purpose of bonding through an adhesive layer made of an aqueous solution containing a resin and further protecting from scratches and dirt during handling on the upper surface of the polarizer protective film layer 2 made of a triacetyl cellulose film. Bonding the surface protection film layer 4 which consists of a polyethylene terephthalate film with a thickness of 40 micrometers through the layer 3, and the adhesive which consists of an aqueous solution containing polyvinyl alcohol and a water-soluble epoxy resin on the other side of the polarizer layer 1 Through the layer 5 made of a cycloolefin resin having a thickness of 70 μm (hereinafter referred to as a functional addition layer 5 (Brand name: Zeonoa, Japan Xeon Co., Ltd.), the release film which consists of an acrylic pressure-sensitive adhesive layer 6 having a thickness of 25 µm on one side thereof and a polyethylene terephthalate film having a thickness of 38 µm thereon. A strip-shaped polarizing plate (size: 1 m × 1 m) formed by bonding the layer 7 was prepared.

[ Example  One]

The band-shaped polarizing plate was used as a carbon dioxide laser (laser light irradiation apparatus: Coherent Co., Ltd.) having a laser wavelength of 9.4 µm from the surface protective film layer of the polarizing plate to the layer immediately before the functional addition layer 5 at right angles to the polarizing plate absorption axis ( The surface protection film layer, the pressure-sensitive adhesive layer, the polarizer protective film layer, the polarizer layer, and the adhesive layer) are cut and processed (cutting conditions: frequency 20 kHz, output: 59 W, speed: 60 m / min), and then fixed ring (110φ, cutting edge) The function addition layer 5 and the adhesive layer 6 were cut | disconnected leaving only the peeling film layer 7 using the angle 20 degrees and 0.3 mm thickness manufactured by Hagihara Industrial Co., Ltd.). The photomicrograph of the polarizing plate cut cross section obtained in this way is shown in FIG. Moreover, although the edge of the fixed ring phosphorus after cutting | disconnecting 150 polarizing plates by this laser (Laser wavelength 9.4 micrometers) and the two-stage cutting method with the fixed ring phosphorus was observed, there was no blade breakage and the remarkable degradation of cutting performance was not seen. .

[ Comparative example  One]

The same band-shaped polarizing plate used in Example 1 was cut | disconnected, leaving only the peeling film layer 7 of the surface bonded together with a board | substrate using only the fixed ring phosphorus used in Example 1. The micrograph of the cut surface of the polarizing plate cut | disconnected 10th from implementation is shown as FIG.

As is apparent from FIG. 6, in the case where the band-shaped polarizing plate is cut using only the fixed ring phosphorus, lifting is observed between the polarizer protective film layer and the surface protective film layer at the tenth cut section. In addition, the fixed ring phosphorus was hardly lifted at the tenth, and as shown in Figs. 7 and 8, defects were seen on the blade tip of the ring phosphorus, and further use was difficult.

One… … Polarizer layer
2… … Polarizer protective film layer
2a ... … Polarizer protective film layer
3 ... … Adhesive layer
4… … Surface protective film layer
5... … Layer made of laser light low absorption rate film
6... … Adhesive layer
7 ... … Release film layer
8… … Board

Claims (7)

On one side of the polarizer layer made of a polyvinyl alcohol-based resin film, a polarizer protective film layer made of a laser light high absorptivity film having an average absorptivity of laser light exceeding 2% is laminated, and on the opposite side to the polarizer layer of the polarizer protective film. The pressure-sensitive adhesive layer is laminated with a surface protection film layer made of a laser light high absorptivity film, and on the other side of the polarizer layer a layer made of a laser light low absorptivity film having an average absorptivity of 2% or less through an adhesive layer and the laser light. A strip-shaped polarizing plate in which a release film layer made of a laser light high absorptivity film is laminated through an adhesive layer on an opposite side to the polarizer layer of the low absorption film layer comprises cutting a layer constituting another polarizing plate leaving only the release film. As a manufacturing method of the polarizing plate to
The manufacturing method of the polarizing plate which cuts from the surface protection film layer to the layer immediately before the layer which consists of a laser beam low absorptivity film, and then cut | disconnects the layer which consists of a laser beam low absorptivity film with a cutter. delete The method according to claim 1,
The laser beam low absorption factor film manufacturing method of the polarizing plate whose average absorption rate of a laser beam is 1% or less. The method according to claim 1,
The manufacturing method of the polarizing plate which has a polarizer protective film which consists of a laser beam high absorptivity film between a polarizer layer and the layer which consists of a laser beam low absorptivity film. The method according to claim 1,
The manufacturing method of the polarizing plate whose laser beam low water absorption film is a cycloolefin polymer film, a polypropylene film, or a polymethyl methacrylate film. The method according to claim 1,
The manufacturing method of the polarizing plate whose laser is a carbon dioxide gas laser. The polarizing plate manufactured by the manufacturing method of the polarizing plate of Claim 1.

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