JP6363344B2 - Method for producing a piece protective polarizing film with an adhesive layer - Google Patents

Description

  The present invention relates to a method for producing a piece protective polarizing film with a pressure-sensitive adhesive layer in which a transparent protective film is laminated only on one side of a polarizer and a pressure-sensitive adhesive layer is laminated directly on the other side. The single protective polarizing film with an adhesive layer obtained by the production method is used alone or as an optical film formed by laminating it, and forms an image display device such as a liquid crystal display device (LCD), an organic EL display device, a CRT, or a PDP. Yes.

  Liquid crystal display devices are rapidly expanding in watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, and the like. The liquid crystal display device visualizes the polarization state by switching of the liquid crystal, and a polarizer is used from the display principle.

  As the polarizer, since it has a high transmittance and a high degree of polarization, for example, an iodine-type polarizer having a stretched structure in which iodine is adsorbed on polyvinyl alcohol is most widely used. Such a polarizer has a disadvantage that the mechanical strength is extremely weak, and the polarizing function is remarkably lowered due to contraction due to heat and moisture. Therefore, the obtained polarizer is immediately bonded to the transparent protective film coated with the adhesive via the adhesive and used as a polarizing film.

  Moreover, when sticking a polarizing film to a liquid crystal cell, an adhesive is normally used. Moreover, since adhesion | attachment of a polarizing film and a liquid crystal cell reduces the loss of light normally, each material is closely_contact | adhered using the adhesive. In such a case, since the adhesive has the merit that a drying step is not required to fix 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. A film is generally used.

  On the other hand, image display devices such as liquid crystal display devices are becoming thinner, and the polarizing film with an adhesive layer is also required to be thinner. For example, by stretching and dyeing a laminate having a resin substrate and a polyvinyl alcohol-based resin layer formed on one side of the resin substrate, a polarizer composed of a thin polarizing film is formed on the resin substrate. Can be obtained (Patent Document 1). Moreover, the transparent protective film is provided only on one side of the polarizer, and the transparent protective film is not provided on the other side, and the adhesive protective layer-attached single protective polarizing film with the adhesive layer is provided on both sides of the polarizer. Compared with a normal polarizing film with a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive layer is provided on a polarizing film provided with a transparent protective film, the number of transparent protective films is less, so a thin type can be achieved.

JP 2000-338329 A

  Liquid crystal display devices are required to have durability that satisfies adhesiveness even under severe conditions such as high temperature or high temperature and high humidity, and does not cause poor appearance. The said durability is calculated | required also about the adhesive layer which concerns on said piece protection polarizing film with an adhesive layer.

  Moreover, when producing the piece protection polarizing film with an adhesive layer using the polarizer which consists of a thin polarizing film formed in the one side of said resin base material, first, a polarizer (polarizing film) is used. After laminating a transparent protective film via an adhesive, and then peeling off the resin base material, by laminating the pressure-sensitive adhesive layer on the other side of the polarizer subjected to the peeling operation, the pressure-sensitive adhesive layer is attached. A piece protective polarizing film is produced. However, in the piece protective polarizing film with the pressure-sensitive adhesive layer obtained by such a conventional production method, a film satisfying the durability has not been obtained.

  An object of this invention is to provide the manufacturing method of the piece protection polarizing film with an adhesive layer which can satisfy durability, even when it applies to a thin polarizer.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found the following method for producing a piece protective polarizing film with an adhesive layer, and have completed the present invention.

That is, the present invention provides a piece-protecting polarizing film with a resin substrate, which has a resin substrate and a polarizer formed on one side of the resin substrate, and a transparent protective film is laminated on the polarizer side. Step (1) to perform,
A step (2) of peeling the resin substrate from the piece protective polarizing film with the resin substrate;
A step (3) of subjecting the surface of the polarizer, from which the resin base material has been peeled off in the step (2), to an activation treatment under the condition that the integrated irradiation amount of activation energy is 0.01 to ² J / cm ² ;
It has the process (4) which laminates | stacks an adhesive layer directly on the surface of the polarizer in which the said process (3) was given, It is related with the manufacturing method of the piece protection polarizing film with an adhesive layer characterized by the above-mentioned.

  In the method for producing a piece protective polarizing film with an adhesive layer, corona treatment, plasma treatment or excimer treatment is suitably employed as the activation treatment in the step (2).

  In the manufacturing method of the said piece protective polarizing film with an adhesive layer, it is preferable that the thickness of the said polarizer is 10 micrometers or less.

  Further, in the method for producing a piece protective polarizing film with an adhesive layer, the polarizer is a continuous web polarizing film made of a polyvinyl alcohol resin in which a dichroic substance is oriented, and a thermoplastic resin substrate. It can be suitably applied to the case where the laminate including the polyvinyl alcohol-based resin layer formed on is obtained by stretching in a two-stage stretching process consisting of air-assisted stretching and boric acid-water stretching.

  In the manufacturing method of the said piece protective polarizing film with an adhesive layer, it is preferable that the said resin base material is an ester resin base material.

  In the method for producing the piece protective polarizing film with the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer laminated in the step (4) is preferably an acrylic pressure-sensitive adhesive layer.

In the method for producing a piece protective polarizing film with an adhesive layer,
Between the step (2) and the step (3),
It is possible to have a step (5) in which the resin base material is peeled off by the step (2) and then peeled after the surface protective film is bonded to the surface of the polarizer.

  In the conventional method for producing a piece protective polarizing film with a pressure-sensitive adhesive layer, after peeling a resin substrate from a piece protective polarizing film with a resin substrate, the surface of a polarizer (for example, a polyvinyl alcohol-based resin film) The pressure-sensitive adhesive layer was laminated. However, it was found that foreign substances such as the resin base material (oligomer and the like) remained on the surface of the polarizer with the peeling of the resin base material. And when the adhesive layer was affixed as it was on the surface of the polarizer in the state where the foreign matter remained, it was found that the foreign matter was mixed into the adhesive layer. The foreign matter is considered not only to impair the adhesiveness (throwing property) between the polarizer and the pressure-sensitive adhesive layer, but also to crystallize and precipitate in the pressure-sensitive adhesive layer to cause a poor appearance. Moreover, even if the said foreign material was not observed in the inspection at the time of the shipment of the piece protection polarizing film with an adhesive layer, it turned out that it may precipitate with time and may become a bright spot.

  In the present invention, after the resin substrate is peeled from the piece-protecting polarizing film with a resin substrate, the surface of the polarizer is subjected to an activation treatment, and then directly adhered to the surface of the activated polarizer. The agent layer is laminated. By such activation treatment, the foreign matter remaining on the surface of the polarizer can be reduced. As a result, it is possible to obtain a piece protective polarizing film with a pressure-sensitive adhesive layer that satisfies the durability related to adhesiveness and appearance defects.

  Further, in the present invention, it is preferable to control the activation energy in the activation process within a predetermined range so that the polarizer is not deteriorated or deteriorated with the activation process. The deterioration of the polarizer is likely to occur when a thin polarizer is used. The control of the activation energy is suitable when the polarizer used for the piece-protecting polarizing film with a resin substrate is a thin polarizer. Therefore, even if the thin protective film is used for the piece-protecting polarizing film with the pressure-sensitive adhesive layer obtained by the production method of the present invention, the optical property is not inferior to that of the polarizer without being activated. For example, the optical durability can be satisfied.

  In addition, in order to further improve the adhesive strength between the polarizer and the transparent protective film, the surface of the polarizer on which the adhesive layer is provided is subjected to an activation treatment, and then the polarizer and the transparent protective film are bonded to each other. Has been proposed (Japanese Patent Laid-Open No. 2009-008660). However, the gazette has a problem of improving the adhesive strength between the polarizer and the transparent protective film. Further, no foreign matter remains on the surface of the polarizer described in the publication.

It is a conceptual diagram which shows an example of embodiment which concerns on the manufacturing method of the piece protection polarizing film with an adhesive layer of this invention. It is a conceptual diagram which shows an example of embodiment which concerns on the manufacturing method of the piece protection polarizing film with an adhesive layer of this invention.

  Below, the manufacturing method of the piece protection polarizing film with an adhesive layer of this invention is demonstrated. In the piece protective polarizing film with an adhesive layer of the present invention, a transparent protective film is provided on one side of a polarizer, and an adhesive layer is directly laminated on the other side of the polarizer. Such a piece protective polarizing film with a pressure-sensitive adhesive layer of the present invention is obtained by sequentially performing the steps (1) to (4) on the piece protective polarizing film with a resin substrate. Hereinafter, steps (1) to (4) will be described with reference to FIG. Moreover, as shown in FIG. 2, a process (5) can be provided between the process (2) and the process (3).

<Step (1)>
In the step (1), the resin base 3 has a polarizer 1 formed on one side of the resin base 3 and a transparent protective film 2 is laminated on the polarizer 1 side. A piece-protected piece protective polarizing film A is prepared.

≪Resin base material≫
Various thermoplastic resins can be used as the material for forming the resin base material. Examples of the thermoplastic resin include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide rheo resins, polycarbonate resins, and copolymer resins thereof. Can be mentioned. Of these, ester resins are preferred from the viewpoint of ease of production and cost reduction. As the ester-based thermoplastic resin substrate, an amorphous ester-based thermoplastic resin substrate or a crystalline ester-based thermoplastic resin substrate can be used.

  Various polarizers can be used as the polarizer. As the polarizer, those obtained by various production methods can be used. Although the thickness of the polarizer can usually be 30 μm or less, the production method of the present invention is suitably applied even when a thin polarizer with a thickness of 10 μm or less is used. From the viewpoint of thinning, the thickness of the polarizer is preferably 1 to 7 μm. Such a thin polarizer is preferable in that the thickness unevenness is small, the visibility is excellent, the dimensional change is small, the durability is excellent, and the thickness of the polarizing film can be reduced.

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

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

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

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

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

  In the present invention, as a polarizer having a thickness of 10 μm or less, it is a continuous web polarizing film made of a PVA-based resin in which a dichroic material is oriented, and is formed on a thermoplastic resin substrate. What was obtained by extending | stretching the laminated body containing this by the two-stage extending | stretching process which consists of an air auxiliary | assistant extending | stretching and boric-acid-water extending | stretching can be used. The thermoplastic resin substrate is preferably an amorphous ester thermoplastic resin substrate or a crystalline ester thermoplastic resin substrate.

The thin polarizing film in the above-mentioned Japanese Patent Application Nos. 2010-269002 and 2010-263692 is a continuous web polarizing film made of a PVA resin in which a dichroic material is oriented, and is amorphous. The laminate including the PVA-based resin layer formed on the ester-based thermoplastic resin base material was stretched in a two-stage stretching process consisting of air-assisted stretching and boric acid-water stretching, so that the thickness was 10 μm or less. Is. Such a thin polarizing film has P> − (10 ^0.929 T ^−42.4 −1) × 100 (where T <42.3) and P ≧, where T is the single transmittance and P is the polarization degree. It is preferable that the optical properties satisfy 99.9 (where T ≧ 42.3).

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

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

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

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

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

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

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

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

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

≪Transparent protective film≫
The piece protective polarizing film A with a resin base material prepared in the step (1) is applied to the polarizer 1 of a laminate (for example, the optical laminate obtained above) having the polarizer 1 on one side of the resin base material 3. The transparent protective film 2 is laminated. In addition, the polarizer 1 and the transparent protective film 2 are normally laminated | stacked through the adhesive bond layer. However, the adhesive layer is not shown in FIGS.

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

  The retardation film of the said resin film can be used for the polarizer protective film of this invention. Examples of the retardation film include those having a front retardation of 40 nm or more and / or a retardation having a thickness direction retardation of 80 nm or more. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a retardation film is used as the polarizer protective film, the retardation film functions also as a polarizer protective film, so that the thickness can be reduced.

  Examples of the retardation film include a birefringent film formed by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching ratio, and the like are appropriately set depending on the retardation value, film material, and thickness.

  The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

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

  An adhesive is used for the adhesion treatment between the polarizer and the transparent protective film. Examples of the adhesive include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, and water-based polyesters. The said adhesive agent is normally used as an adhesive agent which consists of aqueous solution, and contains 0.5 to 60 weight% of solid content normally. In addition to the above, examples of the adhesive between the polarizer and the transparent protective film include an ultraviolet curable adhesive and an electron beam curable adhesive. The electron beam curable polarizing film adhesive exhibits suitable adhesiveness to the various transparent protective films. The adhesive used in the present invention can contain a metal compound filler.

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

  Moreover, when using an aqueous adhesive etc., it is preferable to apply the adhesive 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 to 250 nm. On the other hand, when a curable adhesive is used, the thickness of the adhesive layer is preferably 0.1 to 200 μm. More preferably, it is 0.5-50 micrometers, More preferably, it is 0.5-10 micrometers.

  In addition, in bonding of a polarizer and a transparent protective film, an easily bonding layer can be provided between a transparent protective film and an adhesive bond layer. The easy adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Moreover, you may add another additive for formation of an easily bonding layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat resistance stabilizer may be used.

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

<Step (2)>
At a process (2), the said resin base material 3 is peeled from the said piece protective polarizing film A with a resin base material.

<Step (3)>
In the step (3), an activation treatment is performed on the surface of the polarizer 1 from which the resin substrate 3 has been peeled from the piece-protecting polarizing film A with a resin substrate in the step (2). In FIG. 1 and FIG. 2, the means for performing the activation process is shown as the activation means 4.

  Examples of the activation treatment include corona treatment, plasma treatment, excimer treatment, glow treatment, and ozone treatment. The corona treatment can be performed, for example, by a method in which discharge is performed in normal pressure air using a corona treatment machine manufactured by Kasuga Electric. The plasma treatment can be performed, for example, by a method in which discharge is performed in atmospheric pressure air or an inert gas atmosphere such as nitrogen or argon using a plasma discharger manufactured by Sekisui Chemical Co., Ltd. The excimer treatment can be performed by irradiating an excimer lamp. The excimer lamp is a UV lamp having a wavelength of 180 nm or less in which Xe is enclosed. Glow treatment and ozone treatment can also be performed according to a conventional method. Among these, corona treatment, plasma treatment, or excimer treatment is preferable in terms of equipment cost and processing cost. In particular, the corona treatment or the plasma treatment is preferable because the activation energy can be easily controlled.

The activation treatment is usually performed under the condition that the activation energy is 0.01 to ² J / cm ² . If the activation energy is less than 0.01 J / cm ² , the activation treatment is not sufficient, foreign matter on the surface of the polarizer cannot be sufficiently reduced, and durability (adhesiveness, appearance) is insufficient. On the other hand, when the activation energy exceeds ² J / cm ² , the damage given to the surface of the polarizer tends to increase, and the optical characteristics (optical durability) may not be satisfied. In addition, when the activation energy exceeds ² J / cm ² , the residual foreign matter accompanying the peeling of the resin base material on the surface of the polarizer can be reduced, but there is a possibility that the foreign matter due to the damage may be generated. Durability (adhesiveness, appearance) may be insufficient. In the activation process, it is preferred that the activation energy is 0.01~0.59J / cm ^2, preferably further is 0.4~0.59J / cm ^2.

For example, when the activation treatment is a corona treatment, the activation amount (discharge amount: W / m ² / min) condition is preferably ^{2 to} 83 W / m ² / min, and more preferably ^{2 to} 42 W / m. ² / min is preferable, and 34 to 42 W / m ² / min is more preferable. The gap between the electrode and the sample (polarizer) is usually preferably about 1 to 5 mm, and more preferably 1 to 2 mm.

<Process (4)>
In the step (4), the pressure-sensitive adhesive layer 5 is directly laminated on the surface of the polarizer 1 subjected to the step (3) to produce a piece protective polarizing film B with the pressure-sensitive adhesive layer. In FIG. 1, FIG. 2, the separator 6 is provided in the adhesive layer 5 of the piece protection polarizing film B with an adhesive layer.

  The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. Various pressure-sensitive adhesives can be used as the pressure-sensitive adhesive, such as rubber-based pressure-sensitive adhesive, acrylic pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, vinyl alkyl ether-based pressure-sensitive adhesive, polyvinyl alcohol-based pressure-sensitive adhesive, polyvinyl Examples include pyrrolidone adhesives, polyacrylamide adhesives, and cellulose adhesives. An adhesive base polymer is selected according to the type of the adhesive.

  Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance and heat resistance. The The acrylic pressure-sensitive adhesive contains a (meth) acrylic polymer as a base polymer. The (meth) acrylic polymer usually contains an alkyl (meth) acrylate as a main component as a monomer unit. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning.

  Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer include linear or branched alkyl groups having 1 to 18 carbon atoms. For example, the alkyl group includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, hexyl group, cyclohexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, nonyl group, decyl group. Group, isodecyl group, dodecyl group, isomyristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, and the like. These can be used alone or in combination. The average carbon number of these alkyl groups is preferably 3-9.

  In addition, alkyl (meth) acrylates containing aromatic rings such as phenoxyethyl (meth) acrylate and benzyl (meth) acrylate are used from the viewpoints of adhesive properties, durability, retardation adjustment, refractive index adjustment, and the like. be able to. The alkyl (meth) acrylate containing an aromatic ring can be used by mixing a polymer obtained by polymerizing it with the (meth) acrylic polymer exemplified above, but from the viewpoint of transparency, it contains an aromatic ring. The alkyl (meth) acrylate is preferably copolymerized with the alkyl (meth) acrylate.

  The ratio of the alkyl (meth) acrylate containing the aromatic ring in the (meth) acrylic polymer is 50% by weight or less in the weight ratio of all constituent monomers (100% by weight) of the (meth) acrylic polymer. Can be contained. Furthermore, the content of the alkyl (meth) acrylate containing an aromatic ring is preferably 1 to 35% by weight, more preferably 1 to 20% by weight, further preferably 7 to 18% by weight, and further 10 to 16%. % By weight is preferred.

  In the (meth) acrylic polymer, one or more having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group for the purpose of improving adhesiveness and heat resistance These copolymerizable monomers can be introduced by copolymerization. Specific examples of such copolymerization monomers include, for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid 6 Hydroxyl group-containing monomers such as hydroxyhexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate Carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; acid anhydrides such as maleic anhydride and itaconic anhydride Physical group-containing monomer; Caprolactone adduct of crylic acid; styrene sulfonic acid and allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene Examples thereof include sulfonic acid group-containing monomers such as sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate.

  In addition, (N-substituted) amides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, etc. Monomer; (meth) acrylic acid aminoethyl, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid t-butylaminoethyl and other (meth) acrylic acid alkylaminoalkyl monomers; (meth) acrylic (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl acid and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- ( (Meta) acryloyl- -Succinimide monomers such as oxyoctamethylene succinimide and N-acryloylmorpholine; Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; N-methylitaconimide, N-ethyl Itaconimide monomers such as itaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, and the like are listed as examples of monomers for modification purposes. It is done.

  Further, as modifying monomers, vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N- Vinyl monomers such as vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; (Meth) acrylic acid polyethylene glycol, (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol, (meth) acrylic acid meth Glycol acrylic ester monomers such as polypropylene glycol; acrylic acid ester monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate may also be used. it can. Furthermore, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

  Furthermore, examples of the copolymerizable monomer other than the above include silane-based monomers containing silicon atoms. Examples of the silane monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, and the like.

  Moreover, as a copolymerization monomer, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neodymium Pentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acryloyl such as esterified product of (meth) acrylic acid and polyhydric alcohol such as caprolactone-modified dipentaerythritol hexa (meth) acrylate , Polyfunctional monomers having two or more unsaturated double bonds such as vinyl groups, and unsaturated groups such as (meth) acryloyl groups and vinyl groups as functional groups similar to monomer components in the backbone of polyester, epoxy, urethane, etc. Polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate and the like to which two or more double bonds are added can also be used.

  The (meth) acrylic polymer has alkyl (meth) acrylate as a main component in the weight ratio of all constituent monomers, and the ratio of the copolymerizable monomer in the (meth) acrylic polymer is not particularly limited, but the copolymer The ratio of the monomer is preferably about 0 to 20%, about 0.1 to 15%, and more preferably about 0.1 to 10% in the weight ratio of all the constituent monomers.

  Among these copolymer monomers, a hydroxyl group-containing monomer is preferably used from the viewpoint of adhesiveness and durability. Since the hydroxyl group-containing monomer is rich in reactivity with the intermolecular crosslinking agent, it is preferably used for improving the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer. A hydroxyl group-containing monomer is preferable in terms of reworkability. When the hydroxyl group-containing monomer is contained as a copolymerization monomer, the proportion is preferably 0.01 to 15% by weight, more preferably 0.03 to 10% by weight, and further preferably 0.05 to 7% by weight. .

  A carboxyl group-containing monomer is preferable in terms of achieving both durability and reworkability. When a carboxyl group-containing monomer is contained as a copolymerization monomer, the ratio is preferably 0.05 to 10% by weight. Setting the ratio of the carboxyl group-containing monomer in the above range is preferable in order to prevent foreign matters remaining on the surface of the polarizer from moving to the pressure-sensitive adhesive layer as the resin substrate is peeled off. The proportion of the carboxyl group-containing monomer is particularly effective when it is 4% by weight or less. The proportion of the carboxyl group-containing monomer is preferably 0.05 to 4% by weight, more preferably 0.1 to 3% by weight, and further preferably 0.2 to 2% by weight.

  As the (meth) acrylic polymer of the present invention, those having a weight average molecular weight in the range of 500,000 to 3,000,000 are usually used. In view of durability, particularly heat resistance, it is preferable to use those having a weight average molecular weight of 700,000 to 2,700,000. Furthermore, it is preferable that it is 800,000-2.5 million. A weight average molecular weight of less than 500,000 is not preferable in terms of heat resistance. On the other hand, if the weight average molecular weight is more than 3 million, a large amount of a diluting solvent is required to adjust the viscosity for coating, which is not preferable. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  The production of such a (meth) acrylic polymer can be appropriately selected from known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations. Further, the (meth) acrylic polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  In solution polymerization, for example, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is performed under an inert gas stream such as nitrogen, and a polymerization initiator is added, and the reaction is usually performed at about 50 to 70 ° C. under reaction conditions of about 5 to 30 hours.

  The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. In addition, the weight average molecular weight of a (meth) acrylic-type polymer can be controlled by the usage-amount of a polymerization initiator and a chain transfer agent, and reaction conditions, and the usage-amount is suitably adjusted according to these kinds.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2). -Imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 2,2 '-Azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, VA-057) and other azo initiators, and persulfates such as potassium persulfate and ammonium persulfate , Di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butyl -Oxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3 , 3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) ) Peroxides such as cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, peroxides and sodium bisulfite, peroxides and sodium ascorbate Redox initiators combined with Not intended to be.

  The polymerization initiator may be used alone or in combination of two or more, but the total content is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer. Is preferably about 0.02 to 0.5 parts by weight.

  In order to produce the (meth) acrylic polymer having the weight average molecular weight using, for example, 2,2′-azobisisobutyronitrile as the polymerization initiator, the amount of the polymerization initiator used is a monomer. The amount is preferably about 0.06 to 0.2 part by weight, more preferably about 0.08 to 0.175 part by weight with respect to 100 parts by weight of the total amount of the components.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.1 parts by weight with respect to 100 parts by weight of the total amount of monomer components. Less than or equal to

  Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxy Nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer are exemplified. These emulsifiers may be used alone or in combination of two or more.

  Further, as reactive emulsifiers, as emulsifiers into which radical polymerizable functional groups such as propenyl groups and allyl ether groups are introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 BC-10, BC-20 (all of which are manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria soap SE10N (manufactured by Asahi Denka Kogyo Co., Ltd.), and the like. Reactive emulsifiers are preferable because they are incorporated into the polymer chain after polymerization and thus have improved water resistance. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight from the viewpoint of polymerization stability and mechanical stability with respect to 100 parts by weight of the total amount of monomer components.

  Furthermore, the pressure-sensitive adhesive of the present invention can contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate can be used. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imine crosslinking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. Can be mentioned. Examples of the atom in the organic compound that is covalently bonded or coordinated include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

  The amount of the crosslinking agent used is preferably 0.01 to 20 parts by weight, more preferably 0.03 to 10 parts by weight, with respect to 100 parts by weight of the base polymer (for example, (meth) acrylic polymer). If the crosslinking agent is less than 0.01 parts by weight, the cohesive force of the pressure-sensitive adhesive tends to be insufficient, and foaming may occur during heating. On the other hand, if it exceeds 20 parts by weight, the moisture resistance is not sufficient, Peeling easily occurs in reliability tests.

  Furthermore, the pressure-sensitive adhesive of the present invention can contain a silane coupling agent. The durability can be improved by using a silane coupling agent. Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3, Epoxy group-containing silane coupling agents such as 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N- (1,3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltri (Meth) a, such as ethoxysilane Lil group-containing silane coupling agents, such as isocyanate group-containing silane coupling agents such as 3-isocyanate propyl triethoxysilane and the like.

  The silane coupling agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer. The silane coupling agent is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, further preferably 0.02 to 1 part by weight, and further 0.05 to 0.6 part by weight. Is preferred. It is an amount that improves durability and appropriately maintains the adhesive force to an optical member such as a liquid crystal cell.

  Furthermore, the pressure-sensitive adhesive composition of the present invention may contain other known additives, for example, powders such as ionic compounds, colorants, and pigments, dyes, surfactants, plasticizers, and pressure-sensitive adhesives. Property imparting agent, surface lubricant, leveling agent, softener, antioxidant, anti-aging agent, light stabilizer, UV absorber, polymerization inhibitor, inorganic or organic filler, metal powder, particulate, foil Or the like can be added as appropriate according to the use for which the material is used. Moreover, you may employ | adopt the redox system which added a reducing agent within the controllable range.

  As a method for forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive is applied to a release-treated separator, the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to a polarizer, or polarized light. The pressure-sensitive adhesive is prepared by applying the pressure-sensitive adhesive to the child, drying and removing the polymerization solvent, and forming a pressure-sensitive adhesive layer on the polarizer. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

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

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

  Various methods are used as a method of forming the pressure-sensitive adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  The thickness in particular of an adhesive layer is not restrict | limited, For example, it is about 1-100 micrometers. Preferably, it is 2-50 micrometers, More preferably, it is 2-40 micrometers, More preferably, it is 5-35 micrometers.

  When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a sheet (separator) that has been subjected to a release treatment until practical use.

  Examples of the constituent material of the separator include, for example, 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. A thin film can be used, but a plastic film is preferably used because of its excellent surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as. In particular, the release property from the pressure-sensitive adhesive layer can be further improved by appropriately performing a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator.

  In addition, although the manufacturing method of the piece protection polarizing film with an adhesive layer of this invention has the said process (1) thru | or a process (4), as shown in FIG. 2, a process (5) can be included.

<Step (5)>
In the step (5), the surface protective film 7 is bonded to the surface of the polarizer 1 from which the resin base material 3 has been peeled off in the step (2) between the step (2) and the step (3). It relates to the process of peeling after. FIG. 2 shows a step of bonding the surface protective film 7 as the step (5) -1, and a step of peeling after bonding as the step (5) -2.

  The surface protective film 7 is usually used for temporarily protecting the surface of the polarizer 1 until the step (4) after the step (2). The surface protective film 7 temporarily protects the surface of the polarizer 1. On the other hand, after peeling from the surface of the polarizer 1, the adhesive or the like related to the surface protective film 7 remains on the surface of the polarizer 1 as a foreign substance. It is assumed that However, in the present invention, even when the surface of the polarizer 1 is temporarily protected by the surface protective film 7 in the step (5), the activation treatment is performed in the step (3). The problem of foreign matters remaining on the surface of the polarizer 1 due to the adhesive or the like can also be solved.

<Surface protection film>
The surface protective film usually has a base film and an adhesive layer, and protects the polarizer via the adhesive layer.

  As the base film of the surface protective film, a film material having isotropic property or close to isotropic property is selected from the viewpoints of inspection property and manageability. Examples of film materials include polyester resins such as polyethylene terephthalate film, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, acrylic resins, and the like. Examples thereof include transparent polymers such as resins. Of these, polyester resins are preferred. The base film can be used as a laminate of one kind or two or more kinds of film materials, and a stretched product of the film can also be used. The thickness of the base film is generally 500 μm or less, preferably 10 to 200 μm.

  The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer of the surface protective film includes a (meth) acrylic polymer, a silicone-based polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based or a rubber-based pressure-sensitive adhesive. Can be appropriately selected and used. From the viewpoints of transparency, weather resistance, heat resistance and the like, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferable. The thickness (dry film thickness) of the pressure-sensitive adhesive layer is determined according to the required adhesive force. Usually, it is about 1-100 micrometers, Preferably it is 5-50 micrometers.

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

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

  An optical film obtained by laminating the above optical layer on a single protective polarizing film with a pressure-sensitive adhesive layer can also be formed by a method of laminating separately separately in the manufacturing process of a liquid crystal display device, etc. The product is excellent in quality stability and assembly work, and has the advantage of improving the manufacturing process of a liquid crystal display device and the like. Appropriate bonding means such as an adhesive layer can be used for lamination. In adhering the above-mentioned piece protective polarizing film with an adhesive layer and other optical films, their optical axes can be arranged at an appropriate angle depending on the target retardation characteristics and the like.

  The piece protective polarizing film or optical film with an adhesive layer of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a piece protective polarizing film or an optical film with an adhesive layer, and an illumination system as necessary, and incorporating a drive circuit. In the present invention, there is no particular limitation except that the piece protective polarizing film with an adhesive layer or the optical film according to the present invention is used, and it can be based on the conventional one. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  Appropriate liquid crystal display devices such as a liquid crystal display device in which a single protective polarizing film with an adhesive layer or an optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or reflector used in an illumination system may be formed. it can. In that case, the piece protective polarizing film with a pressure-sensitive adhesive layer or the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When providing a piece protective polarizing film with an adhesive layer or an optical film on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight.
A protective polarizing film was produced.

<Optical film laminate: production of thin polarizing film with resin substrate>
In order to produce a thin polarizing film, first, a laminated body in which a PVA layer having a thickness of 9 μm is formed on an amorphous PET substrate is produced by air-assisted stretching at a stretching temperature of 130 ° C., and then stretched. A colored laminate is produced by dyeing the laminate, and the colored laminate is further stretched integrally with an amorphous PET substrate so that the total draw ratio is 5.94 times by stretching in boric acid in water at a stretching temperature of 65 degrees. Then, drying was performed at 50 ° C. for 4 minutes to produce an optical film laminate including a PVA layer having a thickness of 4 μm. The PVA molecules in the PVA layer formed on the amorphous PET substrate by such two-stage stretching are oriented in the higher order, and the iodine adsorbed by the dyeing is oriented in the one direction as the polyiodine ion complex. It was possible to produce an optical film laminate including a PVA layer having a thickness of 4 μm and constituting a highly functional polarizing film.

<Transparent protective film>
A (meth) acrylic resin film (product name: HX-40UC, manufactured by Toyo Kohan Co., Ltd.) having a thickness of 40 μm was used.

<Creation of pressure-sensitive adhesive layer with separator>
After applying the following pressure-sensitive adhesive (solution) 1 or 2 to the surface of a polyethylene terephthalate film (separator film) treated with a silicone release agent, it is dried for 60 seconds in a 150 ° C. air circulation thermostatic oven, A pressure-sensitive adhesive layer having a thickness of 20 μm was formed to obtain a pressure-sensitive adhesive layer with a separator.

≪Adhesive 1≫
<Preparation of acrylic polymer (A1)>
A monomer mixture containing 94.9 parts of butyl acrylate, 0.1 part of 2-hydroxyethyl acrylate and 5 parts of acrylic acid is charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser. It is. Furthermore, with respect to 100 parts of the monomer mixture (solid content), 0.1 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged with ethyl acetate, and nitrogen gas was introduced while gently stirring. Then, the temperature of the liquid in the flask was kept at around 60 ° C., and a polymerization reaction was carried out for 7 hours. Then, ethyl acetate was added to the obtained reaction liquid, and the solution of the acrylic polymer (A1) of the weight average molecular weight 2 million adjusted to solid content concentration 20% was prepared.

<Preparation of pressure-sensitive adhesive composition>
To 100 parts of the solid content of the acrylic polymer (A1) solution obtained above, 0.1 part of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals: Takenate D110N) and 0.3 part of dibenzoyl peroxide Then, 0.075 part of γ-glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403) was blended to prepare an acrylic pressure-sensitive adhesive solution.

≪Adhesive 2≫
<Preparation of acrylic polymer (A2)>
In Production Example 1, an acrylic polymer having a weight average molecular weight of 1.6 million was obtained in the same manner as in Production Example 1 except that a monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was used as the monomer mixture. A solution of (A2) was prepared.

<Preparation of pressure-sensitive adhesive composition>
0.1 part of trimethylolpropane tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd .: Coronate L) and 0.3 part of dibenzoyl peroxide with respect to 100 parts of the solid content of the acrylic polymer (A2) solution obtained above. Acrylic pressure-sensitive adhesive solution was prepared by blending 0.075 part of γ-glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403).

  Example 1

(Process 1)
While applying a polyvinyl alcohol-based adhesive to the surface of the polarizing film (polarizer) in the optical film laminate (thin polarizing film with a resin base material), the transparent protective film is bonded to the surface of the polarizing film (polarizer). A single protective polarizing film was prepared.

(Process 2)
Subsequently, the amorphous PET base material was peeled from the piece protective polarizing film with a resin base material.

(Process 3)
Next, the surface (single side) of the polarizing film (polarizer) from which the amorphous PET base material was peeled off by the step (2) was applied to a 0.5 J by a corona irradiator (Kasuga Denki Co., Ltd., CT-0212). Corona treatment was performed under the conditions of / cm ² .

(Process 4)
Next, the pressure-sensitive adhesive layer (using pressure-sensitive adhesive 1) formed in the production of the pressure-sensitive adhesive layer with a separator was bonded to the surface of the polarizing film (polarizer) subjected to the step (3), and the pressure-sensitive adhesive layer An attached piece protective polarizing film was obtained.

Examples 2-17, Comparative Examples 1-3
Example 1 and Example 1 except that the means of activation treatment used in step (3) or the integrated irradiation amount and the type of adhesive used in step (4) were changed as shown in Table 1. Similarly, the piece protection polarizing film with an adhesive layer was produced.

  In Examples 8 and 17, as shown in FIG. 2, between the step (2) and the step (3), a surface protective film is bonded to the surface of the polarizer and then peeled off (5). Was provided. As the surface protective film, Toraytec 7832C manufactured by Toray Industries, Inc. was used.

  As shown in Table 1, “plasma” (Kasuga Denki, APW-602f) was used, and “excimer” (USHIO Inc., SUS05) was used. Comparative Example 1 is a case where the activation process is not performed.

[Evaluation]
The following evaluation was performed about the piece protection polarizing film with an adhesive layer obtained by the Example and the comparative example. The results are shown in Table 1. As durability, “adhesive strength”, “peeling” after a predetermined test, and “appearance” were evaluated. As optical durability, “color loss” and “warm water test” after a predetermined test were evaluated.

<Measurement of oligomer amount in pressure-sensitive adhesive layer>
The piece protective polarizing film with an adhesive layer (with a separator) was allowed to stand at 60 ° C. and 90% RH for 500 hours, and then the separator was removed. About 0.025 g of the pressure-sensitive adhesive layer (sample) was collected from the piece protective polarizing film with the pressure-sensitive adhesive layer, added with 1 ml of chloroform, shaken at room temperature for 18 hours, extracted with 5 ml of acetonitrile, and shaken for 3 hours. did. The obtained solution was filtered through a 0.45 ml membrane filter to prepare a sample. A standard product of trimer PET oligomer was adjusted to a constant concentration, a calibration curve was prepared, and the amount of PET oligomer (ppm) contained in the adhesive was determined using the calibration curve. The calibration curve was prepared by measuring by HPLC using a sample whose PET oligomer concentration (ppm) was known.
HPLC system: Agilent Technologies 1200 Series Measurement conditions Column: Agilent Technologies ZORBAX SB-C18
Column temperature: 40 ° C
Column flow rate: 0.8 ml / min
Eluent composition: water / acetonitrile reverse phase gradient injection volume: 5 μl
Detector: PDA
Quantitative method: A standard sample of a PET oligomer trimer was dissolved in chloroform, diluted with acetonitrile, and a preparation was prepared at a constant concentration. A calibration curve was created from the HPLC area and the adjusted concentration, and the amount of PET oligomer in the sample was determined.
The amount of PET oligomer is preferably 50 ppm or less, more preferably 10 ppm or less, and further preferably 5 ppm or less.

<Adhesive strength>
An evaluation sample was prepared by cutting a piece protective polarizing film with an adhesive layer (with a separator) into a width of 25 mm and a length of about 100 mm. After removing the separator from the sample, the pressure-sensitive adhesive layer was pasted on a 0.5 mm-thick non-alkali glass plate (Corning Corp., 1737) with a 2 kg roll reciprocating and allowed to stand at room temperature (23 ° C.) for 1 hour. Then, the adhesive force (N / 25 mm) was measured at a peeling angle of 90 ° and a peeling speed of 300 mm / min.

<Exfoliation and appearance>
Two samples prepared by cutting a piece protective polarizing film with an adhesive layer (with a separator) into a 15-inch size were prepared. After peeling the separator from the sample, it was stuck on both surfaces of 0.5 mm-thick alkali-free glass (Corning Corp., 1737) using a laminator so that each sample was crossed Nicol. Subsequently, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the acrylic-free glass. The sample subjected to such treatment was treated for 500 hours in each atmosphere of 60 ° C./90% RH (humidified condition) and 80 ° C. (heated condition), and then the peeling and appearance were evaluated.

≪peeling≫
Samples treated under humidification conditions or heating conditions were visually evaluated according to the following criteria.
A: No peeling or foaming was observed.
○: Exfoliation or foaming to the extent that it cannot be visually confirmed was observed.
(Triangle | delta): The small peeling or foaming which can be confirmed visually was recognized.
X: Clear peeling or foaming was recognized.

≪Appearance≫
A polarizing film X in which the transparent protective film was adhered only to one side of a polarizer having a polarization degree of 99.98 was separately prepared. A laminate was prepared in which the polarizer side of the polarizing film X and the pressure-sensitive adhesive layer side of the sample treated under humidifying conditions or heating conditions were faced and arranged in crossed Nicols. The polarizing film X and the sample were arranged in a space of 300 mm or less. From the side of the polarizing film X of the laminate, whether or not the bright spot can be confirmed by foreign matter (PET oligomer, etc.) by applying light of 13000 cd / m ² or more is evaluated according to the following criteria with a microscope (200 times) did.
A: The bright spot cannot be confirmed.
X: A bright spot is generated, which affects the display.

<Color loss test>
An evaluation sample was prepared by cutting a piece protective polarizing film with an adhesive layer (with a separator) into 151 mm × 85 mm. After peeling the separator from the sample, it was attached to a non-alkali glass (Corning Corp., 1737) having a thickness of 0.5 mm using a laminator. Subsequently, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the acrylic-free glass. The sample subjected to such treatment was treated for 500 hours in an atmosphere of 60 ° C./95% RH, and then the amount of color loss was measured.
The amount of color loss (μm) was measured with a microscope. The color loss (μm) is preferably 500 μm or less, more preferably 50 μm or less, and further preferably 10 μm or less.

<Hot water test>
An evaluation sample was prepared by cutting a piece protective polarizing film with an adhesive layer (with a separator) into 25 mm × 50 mm. After peeling the separator from the sample, it was attached to a non-alkali glass (Corning Corp., 1737) having a thickness of 0.5 mm using a laminator. Subsequently, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the acrylic-free glass. The sample subjected to such treatment was immersed in warm water at 60 ° C. for 2 hours to perform a warm water test. Next, the sample subjected to the hot water test was taken out, placed in crossed Nicols and observed, and the area T (mm ² ) of the portion where light was not lost was measured with a ruler. From the result, the polarizer preservation ratio (%) was calculated by the following formula.
Polarizer conservation rate (%) = (T / 1250) × 100
The polarizer storage rate (%) is preferably 95% or more, more preferably 96% or more, and even more preferably 98% or more.

A Protective polarizing film with resin base material B Protective polarizing film with pressure sensitive adhesive layer 1 Polarizer 2 Transparent protective film 3 Resin base material 4 Activation means 5 Adhesive layer 6 Separator 7 Surface protective film

Claims (7)

A step (1) of preparing a piece protective polarizing film with a resin base material having a resin base material and a polarizer formed on one side of the resin base material, and having a transparent protective film laminated on the polarizer side When,
A step (2) of peeling the resin substrate from the piece protective polarizing film with the resin substrate;
A step (3) of subjecting the surface of the polarizer, from which the resin base material has been peeled off in the step (2), to an activation treatment under the condition that the integrated irradiation amount of activation energy is 0.01 to ² J / cm ² ;
A method for producing a piece protective polarizing film with a pressure-sensitive adhesive layer, comprising a step (4) of directly laminating a pressure-sensitive adhesive layer on the surface of the polarizer subjected to the step (3).   The method for producing a piece protective polarizing film with an adhesive layer according to claim 1, wherein the activation treatment in the step (2) is a corona treatment, a plasma treatment or an excimer treatment.   The thickness of the said polarizer is 10 micrometers or less, The manufacturing method of the piece protection polarizing film with an adhesive layer of Claim 1 or 2 characterized by the above-mentioned.   The polarizer is a continuous web polarizing film made of a polyvinyl alcohol resin in which a dichroic material is oriented, and a laminate including a polyvinyl alcohol resin layer formed on a thermoplastic resin substrate. The piece-protecting polarized light with a pressure-sensitive adhesive layer according to any one of claims 1 to 3, which is obtained by stretching in a two-stage stretching step comprising air-assisted stretching and boric acid-water stretching. A method for producing a film.   The said resin base material is an ester-type resin base material, The manufacturing method of the piece protection polarizing film with an adhesive layer in any one of Claims 1-4 characterized by the above-mentioned.   The said adhesive layer laminated | stacked at the said process (4) is an acrylic adhesive layer, The manufacturing method of the piece protection polarizing film with an adhesive layer in any one of Claims 1-5 characterized by the above-mentioned. Between the step (2) and the step (3),
The method according to any one of claims 1 to 6, further comprising a step (5) of exfoliating the surface of the polarizer after the resin base material has been exfoliated in the step (2), after the surface protective film is bonded. The manufacturing method of the piece protection polarizing film with an adhesive layer of description.

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