JP7175083B2 - Manufacturing method for package of optical members - Google Patents

Description

The present invention relates to a method for manufacturing a package of optical members. The optical member can form an image display device such as a liquid crystal display (LCD) or an organic EL display.

A liquid crystal display device or the like requires polarizing elements to be arranged on both sides of a liquid crystal cell because of its image forming method, and generally a polarizing film is attached. When sticking the polarizing film to the liquid crystal cell, an adhesive is usually used. Moreover, the polarizing film and the liquid crystal cell are usually adhered to each other using an adhesive to reduce light loss. In such a case, since it has the advantage of not requiring a drying process for fixing the polarizing film, the adhesive is a polarizing film with an adhesive layer provided in advance as an adhesive layer on one side of the polarizing film. Films are commonly used. A release film is usually attached to the adhesive layer of the polarizing film with an adhesive layer.

In addition, in order to protect the polarizing film side surface of the polarizing film with an adhesive layer from scratches and stains that occur during processing and transportation, a surface protective film is usually adhered to the polarizing film side surface of the polarizing film with an adhesive layer. Affixed with an adhesive.

An optical member comprising a polarizing film provided with the pressure-sensitive adhesive layer, the surface protection film, etc. is usually cut into a predetermined size and packed in a laminated state, or in a rolled state and packed. Shipped to the panel maker.

Panel manufacturers attach optical members to cell substrates such as liquid crystal cells in an atmosphere in which temperature and humidity are controlled at a constant level. Curl (Curl refers to a phenomenon of warping, for example, a phenomenon in which a plate-shaped object is entirely warped to one side, or a phenomenon in which a flat plate-shaped object is warped in a wave-like manner.) If this is the case, problems such as poor handleability of the optical member and air bubbles entrapping between the optical member and the cell substrate arise.

In order to suppress the occurrence of curling of the polarizing film (polarizing plate), for example, in Patent Document 1, a first transparent protective film having a moisture permeability of 200 g/m ² /24 h or less is attached to one surface of the polarizer. After forming a laminated body together, a step of bonding a second transparent protective film having a higher moisture permeability than the first transparent protective film to the other surface of the polarizer without winding the laminated body. A method for manufacturing a polarizing plate has been proposed, comprising:

Further, Patent Document 2 discloses a method for manufacturing a polarizing plate in which a transparent protective film (A) is attached to one side of a polarizer and a transparent protective film (B) is attached to the other side of the polarizer with an adhesive,
The polarizer has a moisture content of 15 to 30% by weight,
The transparent protective film (A) and the transparent protective film (B) are made of the same material, the transparent protective film (A) is thicker than the transparent protective film (B), and the transparent protective film (A) is higher than that of the transparent protective film (B).

JP 2005-309394 A Japanese Patent Application Laid-Open No. 2008-122790

However, even if an optical member manufacturer produces an optical member that does not curl, there is a problem that the optical member may curl unnecessarily or unintentionally when the optical member is attached to a cell substrate by a panel manufacturer. there were.

The present invention has been made in view of the above-mentioned problems, and provides a method for manufacturing a package of optical members in which the optical members are less likely to curl when the optical members are attached to a cell substrate such as a liquid crystal cell by a panel manufacturer. intended to provide

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by the following method for manufacturing a package of optical members, and have completed the present invention.

That is, the present invention includes a step A of forming a polarizing film by providing a protective film on one or both sides of a polarizer via an adhesive layer, and forming an optical member by providing at least an adhesive layer and a surface protective film on the polarizing film. and a step C of packing the optical member, wherein
When the equilibrium moisture content of the polarizing film in the optical member from the time when the package is unpacked to the time when the optical member is attached to the cell substrate is X wt%,
In the step C, the moisture content Y weight % of the polarizing film in the optical member is adjusted so that the moisture content Y weight % is not less than the equilibrium moisture content X weight %. It relates to a method of manufacturing an object.

The inventors of the present invention have investigated the cause of the curling of the optical member when the optical member is attached to the cell substrate by a panel manufacturer. They have found that the cause is that the moisture content of the polarizing film in the optical member is lower than the equilibrium moisture content of the polarizing film in the optical member under the atmosphere when the optical member is attached to the cell substrate. Then, the equilibrium moisture content of the polarizing film in the optical member in the atmosphere when the optical member is attached to the cell substrate is known in advance by the panel manufacturer, and when the optical member is packed, the moisture content in the optical member is determined. It has been found that by adjusting the moisture content of the polarizing film so as not to be less than the equilibrium moisture content, curling of the optical member is less likely to occur when the optical member is attached to the cell substrate.

When the moisture content of the polarizing film in the produced optical member is lower than the equilibrium moisture content of the polarizing film in the optical member under the atmosphere when the optical member is attached to the cell substrate, the optical member curls. The reason for this is not clear, but it is thought that when the optical member is attached to the cell substrate, the polarizing film swells due to an increase in the moisture content of the polarizing film, causing wavy curling at the edges.

The equilibrium moisture content means the weight fraction of moisture when left in an atmosphere of constant temperature and constant humidity until the change in moisture content substantially disappears.

In the step C, it is preferable to adjust the moisture content Y so that the difference between the moisture content Y and the equilibrium moisture content X is 0 to 1% by weight.

Moreover, in the step C, it is preferable to adjust the moisture content Y by humidifying the optical member.

Further, between the step B and the step C, a step D of adjusting the moisture content Z so that the moisture content Z of the polarizing film in the optical member does not become less than the equilibrium moisture content X may be included. preferable.

Further, in the step D, it is preferable to adjust the moisture content Z so that the difference between the moisture content Z and the equilibrium moisture content X is 0 to 1% by weight.

Moreover, in the step D, it is preferable to adjust the moisture content Z by humidifying the optical member.

Moreover, it is preferable that the work from unpacking the package to bonding the optical member to the cell substrate is performed in a clean room.

Further, it is preferable that the clean room is adjusted to a constant temperature within the temperature range of 15 to 25° C. and a constant humidity within the relative humidity range of 45 to 65% Rh.

According to the method for producing a package of optical members according to the present invention, curling hardly occurs when the optical member is attached to a cell substrate such as a liquid crystal cell by a panel maker. There is no problem of lamination such as entrapment of air bubbles between the substrate and the cell substrate.

The method for producing a package of optical members of the present invention includes a step A of forming a polarizing film by providing a protective film on one or both sides of a polarizer with an adhesive layer interposed therebetween, and at least an adhesive layer and a surface protection layer on the polarizing film. including a step B of providing a film to produce an optical member, and a step C of packing the optical member,
When the equilibrium moisture content of the polarizing film in the optical member from the time when the package is unpacked to the time when the optical member is attached to the cell substrate is X wt%,
In the step C, the moisture content Y weight % is adjusted so that the moisture content Y weight % of the polarizing film in the optical member is not less than the equilibrium moisture content X weight %.

(Step A)
Step A is a step of forming a polarizing film by providing a protective film on one or both sides of a polarizer with an adhesive layer interposed therebetween, and a known method can be employed.

There are no particular restrictions on the polarizer, and a polarizer using a polyvinyl alcohol-based resin is usually used. As a polarizer, for example, hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films are coated with dichroic dyes such as iodine and dichroic dyes. Polyene-based oriented films such as those obtained by adsorbing a substance and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like can be mentioned. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic substance such as iodine is suitable. The thickness of the polarizer is not particularly limited, and is usually 5-300 μm, preferably 10-200 μm, more preferably 20-100 μm.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by dyeing a polyvinyl alcohol-based film by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. can. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or it may be immersed in an aqueous solution of potassium iodide or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol film with water, dirt and anti-blocking agents on the surface of the polyvinyl alcohol film can be washed away, and by swelling the polyvinyl alcohol film, uneven dyeing and other unevenness can be prevented. be. Stretching may be performed after dyeing with iodine, stretching may be performed while dyeing, or dyeing with iodine may be performed after stretching. It can also be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

As a material for forming the protective film, a material excellent in transparency, mechanical strength, thermal stability, water barrier property, isotropy, etc. is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrenes such as polystyrene and acrylonitrile-styrene copolymer (AS resin). type polymer, polycarbonate type polymer, and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene/propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, imide-based polymers, and sulfone-based polymers , polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or the above Blends of polymers are also examples of polymers that form the protective film.

In addition, one or more types of arbitrary appropriate additives may be contained in the protective film. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the protective film is preferably 50-100% by weight, more preferably 50-99% by weight, still more preferably 60-98% by weight, and particularly preferably 70-97% by weight. If the content of the thermoplastic resin in the protective film is 50% by weight or less, there is a possibility that the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film, or the like can be used. Examples of the retardation film include those having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more. The front retardation is usually controlled in the range of 40-200 nm, and the thickness direction retardation is usually controlled in the range of 80-300 nm. When a retardation film is used as the protective film, the retardation film also functions as a polarizer protective film, so that thickness reduction can be achieved.

The retardation film includes a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching ratio, and the like are appropriately set according to the retardation value, film material, and thickness.

Although the thickness of the protective film can be determined as appropriate, it is generally about 1 to 500 μm from the viewpoints of strength, workability such as handleability, and thinness. In particular, the thickness is preferably 1 to 300 μm, more preferably 5 to 200 μm, further preferably 5 to 150 μm, especially 20 to 100 μm, especially in the case of a thin film.

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

The protective film and the polarizer are laminated via an adhesive layer.

The adhesive layer is formed with an adhesive. The type of adhesive is not particularly limited, and various types can be used. The adhesive layer is not particularly limited as long as it is optically transparent. As the adhesive, various forms such as water-based, solvent-based, hot-melt, and active energy ray-curable types are used. Alternatively, an active energy ray-curable adhesive is suitable.

Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. A water-based adhesive is usually used as an adhesive consisting of an aqueous solution, and usually contains 0.5 to 60% by weight of solids.

Active energy ray-curable adhesives are adhesives that are cured by active energy rays such as electron beams and ultraviolet rays (radical curing type, cationic curing type). can be used. For the active energy ray-curable adhesive, for example, a photoradical-curable adhesive can be used. When a photoradical-curable active energy ray-curable adhesive is used as an ultraviolet-curable adhesive, the adhesive contains a radically polymerizable compound and a photopolymerization initiator.

The method of applying the adhesive is appropriately selected depending on the viscosity of the adhesive and the desired thickness. Examples of coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters and rod coaters. In addition, a method such as a dipping method can be appropriately used for coating.

When a water-based adhesive or the like is used, the adhesive is preferably applied so that the thickness of the finally formed adhesive layer is 30 to 300 nm. The thickness of the adhesive layer is more preferably 60-250 nm. On the other hand, when using an active energy ray-curable adhesive, the thickness of the adhesive layer is preferably 0.1 to 200 μm. More preferably, it is 0.5 to 50 μm, still more preferably 0.5 to 10 μm.

In laminating the polarizer and the protective film, an easy-adhesion layer can be provided between the protective film and the adhesive layer. The easy-adhesion layer can be formed of various resins having, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone system, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, or the like. These polymer resins can be used singly or in combination of two or more. Other additives may be added to form the easy-adhesion layer. More specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat stabilizers may be used.

The easy-adhesion layer is usually provided in advance on the protective film, and the easy-adhesion layer side of the protective film and the polarizer are laminated by an adhesive layer. Formation of the easy-adhesion layer is carried out by applying a material for forming the easy-adhesion layer onto the protective film by a known technique, followed by drying. The easily adhesive layer-forming material is usually prepared as a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of coating, and the like. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, still more preferably 0.05 to 1 μm. A plurality of easy-adhesion layers can be provided, and in this case also, the total thickness of the easy-adhesion layers is preferably within the above range.

(Step B)
Step B is a step of forming an optical member by providing at least an adhesive layer and a surface protective film on the polarizing film, and a known method can be employed.

In the case of both protective polarizing films in which protective films are provided on both sides of the polarizer, a surface protective film is provided directly on one surface of both protective polarizing films or via another layer, and the other surface of both protective polarizing films is directly provided. Alternatively, an adhesive layer is provided via another layer.

In the case of a one-sided protective polarizing film in which a protective film is provided only on one side of a polarizer, a surface protective film is provided directly or via another layer on the protective film side of the one-sided protective polarizing film, and a surface protective film is provided on the one-sided protective polarizing film on the polarizer side. A pressure-sensitive adhesive layer is provided directly or via another layer.

The other layers are not particularly limited, and include known functional layers and optical layers provided on the polarizing film. Examples of optical layers include reflectors, transflective plates, retardation plates (including 1/2 and 1/4 wavelength plates), viewing angle compensation films, and brightness enhancement films. One layer may be provided as the other layer, or two or more layers may be provided.

The pressure-sensitive adhesive layer is provided on one side of the polarizing film in order to bond the polarizing film to a cell substrate such as a liquid crystal cell.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm, preferably 2 to 50 μm, more preferably 2 to 40 μm, still more preferably 5 to 35 μm.

An appropriate adhesive can be used for forming the adhesive layer, and the type thereof is not particularly limited. Examples of adhesives include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, Cellulose-based pressure-sensitive adhesives and the like can be mentioned.

Among these pressure-sensitive adhesives, those having excellent optical transparency, appropriate wettability, cohesiveness, and adhesion properties, and excellent weather resistance and heat resistance are preferably used. Acrylic pressure-sensitive adhesives are preferably used as those exhibiting such characteristics.

As a method for forming an adhesive layer, for example, the adhesive is applied to a release-treated separator or the like, and the polymerization solvent or the like is dried and removed to form an adhesive layer, and then transferred to a polarizing film, or the above method. Examples include a method of applying an adhesive and removing the polymerization solvent by drying to form an adhesive layer on the polarizing film. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

A silicone release liner is preferably used as the release-treated separator. In the step of applying the adhesive on such a liner and drying it to form an adhesive layer, as a method for drying the adhesive, an appropriate method can be appropriately adopted depending on the purpose. Preferably, a method of drying the coating film by heating is used. The drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. A pressure-sensitive adhesive having excellent adhesive properties can be obtained by setting the heating temperature within the above range.

An appropriate drying time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, particularly preferably 10 seconds to 5 minutes.

Various methods are used as a method for forming the pressure-sensitive adhesive layer. Specifically, for example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coating, etc. A method such as an extrusion coating method can be mentioned.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a release-treated sheet (separator) until practical use.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and laminates thereof. Although thin sheets can be used, plastic films are preferably used because of their excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. Examples include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride Examples include polymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films, and the like.

The thickness of the separator is usually about 5-200 μm, preferably about 5-100 μm. If necessary, the separator may be subjected to release and antifouling treatment using a silicone, fluorine, long-chain alkyl or fatty acid amide release agent, silica powder, etc.; It is also possible to perform antistatic treatment such as. In particular, by appropriately subjecting the surface of the separator to release treatment such as silicone treatment, long-chain alkyl treatment, fluorine treatment, etc., the releasability from the pressure-sensitive adhesive layer can be further enhanced.

The surface protection film usually has a base film and an adhesive layer, and protects the polarizing film via the adhesive layer.

As the base film of the surface protection film, a film material having or near isotropy is selected from the viewpoint of inspection property and management property. Examples of film materials include polyester resins such as polyethylene terephthalate film, cellulose resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, acrylic resins, and the like. Examples include transparent polymers such as resins. Among these, polyester-based resins are preferred. The base film may be used as a laminate of one or more film materials, or may be a stretched product of the film. The thickness of the base film is generally 500 μm or less, preferably 10-200 μm.

The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer of the surface protection film includes (meth)acrylic polymers, silicone-based polymers, polyesters, polyurethanes, polyamides, polyethers, and pressure-sensitive adhesives based on polymers such as fluorine-based and rubber-based polymers. An agent can be appropriately selected and used. From the viewpoint of transparency, weather resistance, heat resistance, etc., an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferable. The thickness (dry film thickness) of the adhesive layer is determined according to the required adhesive strength. It is usually about 1 to 100 μm, preferably 5 to 50 μm.

In addition, the surface protective film can be provided with a release treatment layer on the opposite surface of the base film provided with the pressure-sensitive adhesive layer by using a low-adhesion material such as silicone treatment, long-chain alkyl treatment, or fluorine treatment. .

In step B, the order of providing the pressure-sensitive adhesive layer and the surface protection film on the polarizing film is not particularly limited, and the surface protection film may be provided after providing the pressure-sensitive adhesive layer, or the surface protection film may be provided. The pressure-sensitive adhesive layer may be provided after the coating.

The produced optical member may be cut into a predetermined size.

(Process D)
In the present invention, the water content Z (% by weight) of the polarizing film in the produced optical member is not less than the equilibrium water content X (% by weight) between the step B and the step C below. It is preferable to include a step D of adjusting the moisture content Z (% by weight).

The method of adjusting the moisture content Z (% by weight) is not particularly limited, but it is preferable to perform a humidification treatment. (2) winding the produced optical member around a roll in a humidified atmosphere; (3) blowing humidified air onto the cut optical member; (4) humidifying the cut optical member. A method of preserving in an atmosphere can be mentioned. When the moisture content Z is too large compared to the equilibrium moisture content X, dehumidification treatment may be performed to reduce the difference between the moisture content Z and the equilibrium moisture content X.

In the step D, it is preferable to adjust the moisture content Z so that the difference between the moisture content Z and the equilibrium moisture content X is 0 to 1% by weight. It is more preferable to adjust the moisture content Z so that the difference between the two is 0 to 0.5% by weight.

The temperature and relative humidity during the humidification treatment must be appropriately adjusted based on the equilibrium moisture content X, but usually the temperature is about 15 to 25° C. and the relative humidity is about 45 to 65% Rh. Incidentally, the conveying speed of the optical member is usually about 1 to 40 m/min.

(Process C)
Step C is a step of packing the optical member. In the step C, the moisture content Y (% by weight) is adjusted so that the moisture content Y (% by weight) of the polarizing film in the optical member is not less than the equilibrium moisture content X (% by weight). As a method for adjusting the moisture content Y (% by weight), there is a method of packing the optical member in a humidified atmosphere.

The optical member is preferably packed in a temperature-controlled and humidity-controlled atmosphere so that the difference between the moisture content Y and the equilibrium moisture content X is 0 to 1% by weight. It is more preferable that the temperature and humidity are controlled so that the difference from the equilibrium moisture content X is 0 to 0.5% by weight.

The temperature and relative humidity at the time of packing need to be appropriately adjusted based on the equilibrium moisture content X, but usually the temperature is about 15 to 25° C. and the relative humidity is about 45 to 65% Rh.

In the panel maker, the optical member is taken out from the package, and the optical member is attached to the cell substrate in an atmosphere in which the temperature and humidity are controlled to be constant. The work from unpacking the package to bonding the optical member to the cell substrate is preferably performed in a clean room. Further, it is preferable that the clean room is adjusted to a constant temperature within the temperature range of 15 to 25° C. and a constant humidity within the relative humidity range of 45 to 65% Rh.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples shown below. All parts and percentages in each example are based on weight.

(Preparation of UV curable adhesive)
40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO) and 3 parts by weight of a photoinitiator "IRGACURE 819" (manufactured by BASF) were mixed to prepare an ultraviolet curing adhesive.

Example 1
<Preparation of polarizing film for measuring equilibrium moisture content>
On the bonding surface of a protective film and a retardation film (manufactured by Zeon, trade name: ZB12-50135, thickness: 52 μm), which is an acrylic resin film with a thickness of 40 μm and has a lactone ring structure and has been corona-treated for easy adhesion, The above UV curable adhesive was applied to a thickness of 0.7 μm after curing, and laminated on both sides of a polarizer (trade name: PS4500, thickness: 45 μm, manufactured by Kuraray Co., Ltd.) using a roll machine. After that, the adhesive was cured by irradiating ultraviolet rays to produce a polarizing film. When the equilibrium moisture content of the produced polarizing film was measured by the following method, the equilibrium moisture content X in an atmosphere with a temperature of 20° C. and a relative humidity of 55% Rh was 2.5% by weight.

(Measurement of equilibrium moisture content X of polarizing film)
Three samples each having a size of 10 cm×10 cm were cut from the produced polarizing film (TD width 1200 mm) from the central portion in the TD width direction and both ends (6.5 cm inside from the end). The sample was left in an atmosphere of 20° C. and 55% Rh relative humidity for 24 hours, and then the weight W1 of the sample was measured. Next, the sample was dried at 120° C. for 5 hours, and the weight W0 of the dried sample was measured. The equilibrium moisture content of the sample (polarizing film) in an atmosphere of 20° C. and 55% Rh relative humidity was calculated by the following formula. The average value of the equilibrium moisture content of the three samples (polarizing films) was defined as the equilibrium moisture content X.
Equilibrium moisture content X (% by weight) of the polarizing film = {(W1-W0)/W1} × 100

<Preparation of polarizing film>
A polarizing film was produced in the same manner as described above. The moisture content P of the produced polarizing film was measured by the following method and found to be 2.9% by weight.

(Measurement of moisture content P of polarizing film)
Three samples each having a size of 10 cm×10 cm were cut from the produced polarizing film (TD width 1200 mm) from the central portion in the TD width direction and both ends (6.5 cm inside from the end). A weight W2 of the sample before drying was measured. Also, the sample was dried at 120° C. for 5 hours, and the weight W0 of the dried sample was measured. The moisture content of the produced sample (polarizing film) was calculated by the following formula. The average moisture content of the three samples (polarizing films) was defined as the moisture content P.
Moisture content of the polarizing film P (% by weight) = {(W2-W0) / W2} × 100

<Preparation of polarizing film with adhesive layer>
(Preparation of adhesive composition)
A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was added to 100 parts of the monomer mixture (solid content) together with ethyl acetate, and nitrogen gas was introduced while gently stirring. After purging with nitrogen, the temperature of the liquid in the flask was maintained at around 60° C., and the polymerization reaction was carried out for 7 hours. Thereafter, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic polymer having a weight-average molecular weight of 1,400,000, adjusted to a solid content concentration of 30%.
Per 100 parts of the solid content of the acrylic polymer solution, 0.2 parts of ethylmethylpyrrolidinium-bis(trifluoromethanesulfonyl)imide (manufactured by Tokyo Chemical Industry Co., Ltd.) and lithium bis(trifluoromethanesulfonyl)imide (Mitsubishi Materials Electronics Kasei Co., Ltd.) 1 part, and further, 0.1 part of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals: Takenate D110N), 0.3 parts of dibenzoyl peroxide, and γ-glycidoxypropyl methoxy 0.075 parts of silane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403) was blended to prepare an acrylic adhesive solution.

(Formation of adhesive layer)
The acrylic pressure-sensitive adhesive solution is evenly coated with a fountain coater on the surface of a polyethylene terephthalate film (separator film) treated with a silicone release agent, dried in an air circulation constant temperature oven at 155 ° C. for 2 minutes, A pressure-sensitive adhesive layer having a thickness of 20 μm was formed on the surface of the separator film.

(Preparation of polarizing film with adhesive layer)
While sending out the polarizing film from a roll, the pressure-sensitive adhesive layer formed on the release-treated surface of the separator film was attached to the retardation film of the polarizing film to prepare a polarizing film with an adhesive layer. Three film pieces each having a size of 10 cm×10 cm were cut from the produced polarizing film with an adhesive layer (TD width 1200 mm) from the central portion and both ends (6.5 cm inside from the end) in the TD width direction. A sample (polarizing film) for measuring the moisture content Q was obtained by removing the pressure-sensitive adhesive layer and the separator film from the film piece. The moisture content Q of the sample (polarizing film) was measured by the following method and found to be 2.6% by weight.

(Measurement of moisture content Q of polarizing film)
A weight W3 of the sample (polarizing film) before drying was measured. Also, the sample (polarizing film) was dried at 120° C. for 5 hours, and the weight W0 of the dried sample (polarizing film) was measured. The moisture content Q of the sample (polarizing film) was calculated by the following formula. In addition, the average value of the moisture contents of the three samples (polarizing films) was defined as the moisture content Q.
Moisture content Q (% by weight) of the polarizing film = {(W3-W0) / W3} × 100

<Production of polarizing film (optical member) with adhesive layer and surface protective film, and adjustment of moisture content Z1 of polarizing film>
(Production of surface protection film)
An acrylic adhesive layer (thickness: 23 μm) was formed on a PET film (thickness: 38 μm) to prepare a surface protection film.
(Preparation of polarizing film with adhesive layer and surface protective film)
While sending out the polarizing film with an adhesive layer from a roll, the adhesive layer of the surface protective film is attached to the protective film of the polarizing film with an adhesive layer to produce a polarizing film with an adhesive layer and a surface protective film. did.
(Adjustment of moisture content Z1 of polarizing film)
When winding the prepared polarizing film with an adhesive layer and a surface protective film on a roll, while spraying humidified air at a temperature of 23 ° C. and a relative humidity of 65% Rh on the adhesive layer and the polarizing film with a surface protective film at 500 mL / h. Wound on a roll. After 24 hours, the polarizing film with the adhesive layer and the surface protective film was unwound from the roll, and the central part and both ends (edges) in the TD width direction of the polarizing film with the adhesive layer and the surface protective film (TD width 1200 mm) Three pieces of film measuring 10 cm x 10 cm were cut from the inside (6.5 cm from the inside). A sample (polarizing film) for measuring the moisture content Z1 was obtained by removing the pressure-sensitive adhesive layer, the separator film, and the surface protective film from the film piece. The moisture content Z1 of the sample (polarizing film) was measured by the following method and found to be 2.5% by weight.

(Measurement of moisture content Z1 of polarizing film)
A weight W4 of the sample (polarizing film) before drying was measured. Also, the sample (polarizing film) was dried at 120° C. for 5 hours, and the weight W0 of the dried sample (polarizing film) was measured. The moisture content Z1 of the sample (polarizing film) was calculated by the following formula. The average moisture content of the three samples (polarizing films) was taken as the moisture content Z1.
Moisture content Z1 (% by weight) of the polarizing film = {(W4-W0) / W4} × 100

<Cut process of polarizing film with pressure-sensitive adhesive layer and surface protective film, and adjustment of moisture content Z2 of polarizing film>
(cutting process)
While feeding the pressure-sensitive adhesive layer and the polarizing film with a surface protective film from the roll, it was cut into a size of 400 mm in MD length×1200 mm in TD width to obtain an optical member.
(Adjustment of moisture content Z2 of polarizing film)
While transporting the optical member obtained by cutting, humidified air having a temperature of 23° C. and a relative humidity of 65% Rh was blown onto the optical member at 500 mL/h. After that, three pieces of film having a size of 10 cm×10 cm were cut from the central portion and both ends (6.5 cm inside from the end) of the optical member (TD width 1200 mm) in the TD width direction. A sample (polarizing film) for measuring the moisture content Z2 was obtained by removing the pressure-sensitive adhesive layer, the separator film, and the surface protective film from the film piece. The moisture content Z2 of the sample (polarizing film) was measured by the following method and found to be 2.5% by weight.

(Measurement of moisture content Z2 of polarizing film)
A weight W5 of the sample (polarizing film) before drying was measured. Also, the sample (polarizing film) was dried at 120° C. for 5 hours, and the weight W0 of the dried sample (polarizing film) was measured. The moisture content Z2 of the sample (polarizing film) was calculated by the following formula. The average moisture content of the three samples (polarizing films) was taken as the moisture content Z2.
Moisture content Z2 (% by weight) of the polarizing film = {(W5-W0) / W5} × 100

<Packaging of optical components>
The optical member was packaged together with humidified air in a humidified atmosphere at a temperature of 23° C. and a relative humidity of 65% Rh. After that, the optical member was taken out of the packing bag, and three pieces of film having a size of 10 cm × 10 cm were taken from the center and both ends (6.5 cm from the end) in the TD width direction of the optical member (TD width 1200 mm). cut out. A sample (polarizing film) for measuring the moisture content Y was obtained by removing the pressure-sensitive adhesive layer, the separator film, and the surface protective film from the film piece. The moisture content Y of the sample (polarizing film) was measured in the same manner as described above and found to be 2.5% by weight. In addition, the average value of the moisture content of the three samples (polarizing film) was made into the moisture content Y. FIG. The moisture content Y of the polarizing film in the packed optical member was the same as the equilibrium moisture content X described above.

Examples 2-5, Comparative Examples 1-2
An optical member was produced in the same manner as in Example 1, except that the type and thickness of the protective film, the type and thickness of the retardation film, and the presence or absence of humidification treatment were changed as shown in Table 1. and packed. Also, in the same manner as in Example 1, the moisture content of each polarizing film was measured.

In addition, the coating layer of Example 2 was formed by the following method.
Ultraviolet curable urethane acrylate resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "UV1700B", solid content 100%) 50 parts by weight, and polyfunctional acrylate (Osaka organic chemical industry Co., Ltd., trade name "Viscoat #300", solid content 100%) 50 parts by weight was prepared. Per 100 parts by weight of the resin solid content of the resin, copolymer particles of acrylic and styrene as particles (manufactured by Sekisui Plastics Co., Ltd., trade name "Techpolymer", weight average particle size: 3.0 μm, refractive index: 1 .520), 1.5 parts by weight of synthetic smectite (manufactured by Co-op Chemical Co., Ltd., trade name "Lucentite SAN"), which is an organic clay as a thixotropy-imparting agent, and a photopolymerization initiator (manufactured by BASF, 3 parts by weight of "Irgacure 907" (trade name) and 0.2 part of a leveling agent (trade name "PC4100" manufactured by DIC Corporation, solid content 10%) were mixed. The organic clay was used after being diluted with toluene so that the solid content was 6.0%. This mixture was diluted with a toluene/MIBK (methyl isobutyl ketone) mixed solvent (weight ratio 80/20) so that the solid content concentration was 40% by weight to prepare a coating liquid. The coating liquid was applied onto the protective film of the polarizing film using a comma coater to form a coating film. Then, the film on which this coating film was formed was conveyed to a drying process while being tilted at an angle of about 30°. In the drying step, the coating film was dried by heating at 100° C. for 2 minutes. Thereafter, the coating film was cured by irradiating ultraviolet light with an accumulated light quantity of 300 mJ/cm ² from a high-pressure mercury lamp to form a coating layer having a thickness of 7.5 μm.

The optical members obtained in the above Examples and Comparative Examples were evaluated as follows. Table 1 shows the results.
(Method for evaluating curl amount)
A square sample of 150 mm on a side was cut out from the fabricated optical member at three locations: both ends (from 6.5 cm inside from the edge) and the center, with one corner leading in the MD direction as shown in the figure below. Place the sample on a horizontal measuring table so that it becomes convex downward due to curling, measure the height from the measuring table at each corner (4 points) in the MD and TD directions, and take the maximum value as the amount of curl. (mm). In addition, the case of curling toward the separator side (convex state toward the surface protection film side) was taken as negative, and the opposite case was taken as positive.

The films in Table 1 are as follows.
Acrylic resin film: Acrylic resin film TG60UL used in Example 1: Fuji Film Co., Ltd. Cosmo Function: Toyobo Co., Ltd. ZB12-50135: Zeon Co., Ltd. KC4DR-1: Konica Co., Ltd.

The optical member of the present invention is used alone or in the form of an optical film in which it is laminated for use in image display devices such as liquid crystal display devices (LCD) and organic EL display devices.

Claims (7)

A step A of providing a protective film on one or both sides of a polarizer via an adhesive layer to prepare a polarizing film, a step B of providing at least an adhesive layer and a surface protective film on the polarizing film to prepare an optical member, and A method for manufacturing a package of optical members, including a step C of packing the optical member,
The package is to be unpacked after manufacturing,
When the equilibrium moisture content of the polarizing film in the optical member from the time when the package is unpacked to the time when the optical member is attached to the cell substrate is X wt%,
including a step D of adjusting the moisture content Z so that the moisture content Z of the polarizing film in the optical member does not become less than the equilibrium moisture content X between the steps B and C;
In the step C, the moisture content Y weight % of the polarizing film in the optical member is adjusted so that the moisture content Y weight % is not less than the equilibrium moisture content X weight %. A method of making things. 2. The method for manufacturing a package of optical members according to claim 1, wherein in the step C, the moisture content Y is adjusted so that the difference between the moisture content Y and the equilibrium moisture content X is 0 to 1% by weight. . 3. The method for manufacturing a package of optical members according to claim 1, wherein in the step C, the moisture content Y is adjusted by humidifying the optical members. The optical member according to any one of claims 1 to 3 , wherein in the step D, the moisture content Z is adjusted so that the difference between the moisture content Z and the equilibrium moisture content X is 0 to 1% by weight. The method of manufacturing the package. 5. The method for producing a package of optical members according to claim 1 , wherein in said step D, said moisture content Z is adjusted by humidifying said optical member. 6. The method for manufacturing a package of optical members according to claim 1 , wherein operations from unpacking the package to bonding the optical member to the cell substrate are performed in a clean room. 7. The method for manufacturing a package of optical members according to claim 6 , wherein the clean room is adjusted to a constant temperature within a temperature range of 15 to 25° C. and a constant humidity within a relative humidity of 45 to 65% Rh. .