WO2018180999A1

WO2018180999A1 - One-side-protected polarizing film with pressure-sensitive adhesive layer, image display device, and continuous production method therefor

Info

Publication number: WO2018180999A1
Application number: PCT/JP2018/011726
Authority: WO
Inventors: 有森本; 雄祐外山; 藤田　雅人; 卓江原
Original assignee: 日東電工株式会社
Priority date: 2017-03-29
Filing date: 2018-03-23
Publication date: 2018-10-04
Also published as: CN110462473A; CN110462473B

Abstract

The purpose of the present invention is to provide a one-side-protected polarizing film having a pressure-sensitive adhesive layer, which exhibits excellent reworkability and is capable of suppressing defects resulting from nanoslits without having to provide a coating layer between a polarizer and a pressure-sensitive adhesive layer. This one-side-protected polarizing film with a pressure-sensitive adhesive layer has a one-side-protected polarizing film having a protective film that is disposed on only one surface of a polarizer, and a pressure-sensitive adhesive layer that is disposed, either directly or via a coating layer, on the polarizer side of the one-side-protected polarizing film, the polarizing film being characterized in that: the pressure-sensitive adhesive layer has a storage elastic modulus of at least 7.0×107 Pa at minus 40°C; the pressure-sensitive adhesive layer has a tack strength of at most 8 N/25 mm at a peel rate of 300 mm/min and a peel angle of 90° with respect to an alkali-free glass surface and also has a tack strength of at most 8 N/25 mm at a peel rate of 300 mm/min and a peel angle of 90° with respect to an ITO film surface of ITO film-coated glass.

Description

Single protective polarizing film with pressure-sensitive adhesive layer, image display device, and continuous production method thereof

The present invention relates to a piece protective polarizing film provided with a protective film only on one side of a polarizer and a piece protective polarizing film with a pressure sensitive adhesive layer having a pressure sensitive adhesive layer. The above-mentioned piece protective polarizing film with an adhesive layer can form an image display device such as a liquid crystal display device (LCD) or an organic EL display device alone or as an optical film obtained by laminating it.

In a liquid crystal display device, it is indispensable to dispose polarizing films on both sides of a glass substrate that forms the surface of a liquid crystal panel because of its image forming method. In general, a polarizing film in which a protective film is bonded to one or both sides of a polarizer made of a dichroic material such as a polyvinyl alcohol film and iodine with a polyvinyl alcohol adhesive or the like is used. .

When adhering the polarizing film to a liquid crystal cell or the like, an adhesive is usually used. In addition, since the polarizing film can be fixed instantaneously and has a merit such that a drying step is not required to fix the polarizing film, the adhesive is provided in advance as an adhesive layer on one side of the polarizing film. . That is, a piece protective polarizing film with an adhesive layer is generally used for attaching the polarizing film.

In addition, a polarizing film or a piece protective polarizing film with a pressure-sensitive adhesive layer is a polarizer in a harsh environment of a thermal shock (for example, a heat shock test in which a temperature condition of −30 ° C. and 80 ° C. is repeated or a test at a high temperature of 100 ° C.). There is a problem that cracks (through cracks) are likely to occur in the entire absorption axis direction of the polarizer due to the change in the shrinkage stress. That is, the piece protective polarizing film with an adhesive layer was not sufficiently durable due to thermal shock in the harsh environment. In particular, from the viewpoint of thinning, a single-protective polarizing film with a pressure-sensitive adhesive layer using a single-protective polarizing film provided with a protective film only on one side of a polarizer has insufficient durability due to the thermal shock. Moreover, the penetration crack produced by the said thermal shock was easy to generate | occur | produce when the size of a polarizing film became large.

For example, in order to provide high durability in a high temperature environment, the adhesive layer of the piece protective polarizing film with an adhesive layer has a storage elastic modulus at 23 ° C. of 0.2 to 10 MPa and a thickness of 2 μm to 25 μm. It has been proposed to use less than (Patent Document 1). In addition, in order to give good durability even in a high temperature environment, a polarizing layer in which a pressure-sensitive adhesive layer is provided on one side of the polarizer and a protective layer made of a transparent resin film is provided on the other side of the polarizer. In the plate, it has been proposed that the pressure-sensitive adhesive layer has a storage elastic modulus of 0.15 to 1 MPa in a temperature range of 23 to 80 ° C. (Patent Document 2). Further, in order to suppress the occurrence of the through cracks, as the pressure-sensitive adhesive layer of the piece protective polarizing film with the pressure-sensitive adhesive layer, the shrinkage force in the direction perpendicular to the absorption axis of the polarizer is controlled to be small, and the pressure-sensitive adhesive layer It has been proposed to use one having a storage elastic modulus at 23 ° C. of 0.20 MPa or more (Patent Document 3). Thinning is also performed for polarizers, and for example, a thin polarizer exhibiting high orientation in which optical characteristics of single transmittance and polarization degree are controlled has been proposed (Patent Document 4).

However, in Patent Document 1, although the durability is satisfied, since the thickness of the polarizer is as large as 25 μm, it is not possible to prevent the occurrence of through cracks due to the contraction stress of the polarizer. Further, since Patent Documents 1 to 3 have an object to improve the durability of the piece protective polarizing film with an adhesive layer, boric acid used for a polarizer is relatively large. When the amount of boric acid contained in the polarizer is greater than a specific value, crosslinking with boric acid is promoted during heating, and the contraction stress of the polarizer increases, which is not preferable from the viewpoint of suppressing the occurrence of through cracks. I also understood that. That is, in Patent Documents 1 to 3, although the through cracks can be prevented to some extent by controlling the storage elastic modulus of the pressure-sensitive adhesive layer, it cannot be said that the occurrence of the through cracks can be sufficiently suppressed.

On the other hand, thinning is also done for polarizers. When the polarizer used for the piece protective polarizing film with the pressure-sensitive adhesive layer is thinned, the change in the contraction stress of the polarizer becomes small. Therefore, it has been found that the thinned polarizer can suppress the occurrence of the through cracks.

However, in the piece protective polarizing film with the pressure-sensitive adhesive layer in which the generation of the through cracks is suppressed, when the optical properties are controlled and the polarizer is thin as in Patent Document 4 (for example, when the thickness is 12 μm or less). Includes a slit that is partially fine in the direction of the absorption axis of the polarizer when a mechanical impact is applied to the piece protective polarizing film with an adhesive layer (including a case where a load due to convex folding is applied to the polarizer side). Hereinafter, it was also found that nanoslits were generated. It was also found that the nano slits occur regardless of the size of the polarizing film. Furthermore, it was also found that the nano slit does not occur when both protective polarizing films having protective films on both sides of the polarizer are used. In addition, when a through crack occurs in the polarizer, the stress around the through crack is released, so the through crack does not occur adjacently. I found it to happen. Moreover, although the penetration crack has the progressive property extended in the absorption-axis direction of the polarizer in which the crack generate | occur | produced, it turned out that a nano slit does not have the said progressive property. As described above, the nano slit is a new problem that occurs when the polarizer is thin and the optical characteristics are controlled within a predetermined range in the single-protective polarizing film in which the generation of through cracks is suppressed. It has been found that this is a problem caused by a phenomenon different from the above-described through crack.

Moreover, since the nano slit is extremely thin, it cannot be detected under a normal environment. Therefore, even if nano-slits are generated in the polarizer, it is difficult at first glance to confirm defects due to light leakage in the adhesive protective layer-attached piece protective polarizing film. That is, usually, the piece-protecting polarizing film is produced in the form of a long film and automatically inspected for defects by optical inspection, but it is difficult to detect nanoslits as defects by this defect inspection. The defect due to the nano slit can be detected by spreading the nano slit in the width direction when the piece protective polarizing film with an adhesive layer is attached to the glass substrate of the image display panel and then placed in a heating environment. It was also found that (for example, the presence or absence of light leakage).

Therefore, in the piece protective polarizing film with a pressure-sensitive adhesive layer using a thin polarizer, it is desired to suppress not only through cracks but also defects due to nano slits. Furthermore, since the single protective polarizing film with an adhesive layer is thinner than a polarizing film having a protective film on both sides, the polarizing film is likely to be broken or broken during handling.

In order to suppress defects due to the nano slits, a technique of providing a transparent layer (coating layer) between the polarizer and the pressure-sensitive adhesive layer of the piece protective polarizing film with the pressure-sensitive adhesive layer has been proposed (Patent Document 5). Providing the transparent layer makes it difficult for the polarizing film to bend when an external stress is applied to the polarizing film, so that the generation of nano slits can be suppressed.

JP 2010-44211 A JP 2008-197309 A JP 2013-72951 A Japanese Patent No. 4751481 Japanese Patent No. 6077718

In addition, when a glass substrate that forms the surface of a liquid crystal panel or an ITO film provided on a glass substrate is bonded to a piece protective polarizing film with an adhesive layer, foreign matter or bubbles are mixed and a bonding error occurs. In this case, it is necessary to peel the polarizing film from the glass substrate or the ITO film. The piece protective polarizing film with a pressure-sensitive adhesive layer using a thin polarizer has a thin polarizer, and the protective film is provided only on one side of the polarizer, so the overall thickness is very thin. Therefore, the conventional protective film with a pressure-sensitive adhesive layer using a thin polarizer has a problem that it tends to break when it is peeled off from a glass substrate or an ITO film.

The present invention provides a piece-protecting polarizing film with a pressure-sensitive adhesive layer that can suppress defects due to nano-slits without providing a coating layer between the polarizer and the pressure-sensitive adhesive layer, and is excellent in reworkability. Objective.

Another object of the present invention is to provide an image display device having the above-mentioned piece protective polarizing film with an adhesive layer, and a continuous production method thereof.

As a result of intensive studies, the inventors of the present application have found that the above-described problems can be solved by the following piece protective polarizing film with an adhesive layer, and have reached the present invention.

That is, the present invention provides a single protective polarizing film having a protective film only on one side of a polarizer, and a single protective polarizing film with an adhesive layer having an adhesive layer directly or via a coating layer on the polarizer side of the single protective polarizing film. Because
The pressure-sensitive adhesive layer has a storage elastic modulus at −40 ° C. of 7.0 × 10 ⁷ Pa or more,
The pressure-sensitive adhesive layer has a peel rate of 300 N / min and a peel angle of 90 degrees with respect to the alkali-free glass surface of 8 N / 25 mm or less, and the pressure-sensitive adhesive layer has a peel rate with respect to the ITO film surface of the glass with ITO film. It is related with the piece protective polarizing film with an adhesive layer characterized by the adhesive force in 300 mm / min and peeling angle 90 degree | times being 8 N / 25mm or less.

As a result of intensive studies on the relationship between the physical properties of the pressure-sensitive adhesive layer provided on the polarizer side of the single-protective polarizing film and the number of nano-slits, the present inventors have determined that the storage modulus and nano It was found that there was a correlation with the number of slits. Specifically, in general, the storage elastic modulus of the pressure-sensitive adhesive layer when external stress is applied to the pressure-sensitive adhesive layer at a high speed is higher than that when external stress is applied at a low speed. Moreover, the storage elastic modulus in the low temperature area | region of an adhesive layer becomes high compared with the storage elastic modulus in a high temperature area | region. That is, the storage elastic modulus of the pressure-sensitive adhesive layer when external stress is applied to the pressure-sensitive adhesive layer at a high speed exhibits the same physical property tendency (the storage elastic modulus tends to increase) as the storage elastic modulus in the low-temperature region of the pressure-sensitive adhesive layer. . On the other hand, when manufacturing a liquid crystal panel or using a liquid crystal display device, most of the external stress is considered to be applied to the piece protective polarizing film with the adhesive layer at a high speed. It is thought that the case where it adds at high speed tends to generate | occur | produce rather than the case where it adds to the piece protection polarizing film with an agent layer. Therefore, it may be possible to examine the relationship between the storage modulus of the adhesive layer and the number of nanoslits when external stress is applied to the adhesive layer at high speed, but external stress is applied to the adhesive layer at high speed. It is difficult to measure the storage elastic modulus of the pressure-sensitive adhesive layer. Therefore, when the external stress is applied to the adhesive layer at a high speed, the storage elastic modulus in the low temperature region of the adhesive layer showing the same physical property tendency as the storage elastic modulus of the adhesive layer, and the external stress is attached to the adhesive layer at a high speed. When we examined the relationship between the number of nanoslits when applied to a piece of protective polarizing film, the storage modulus of the adhesive layer in the low-temperature region, especially -40 ° C, and the external stress were high, and the piece was protected with the adhesive layer. It has been found that there is a clear correlation with the number of nanoslits when added to the polarizing film. Further, by providing a pressure-sensitive adhesive layer having a storage elastic modulus at −40 ° C. of 7.0 × 10 ⁷ Pa or more on the polarizer side of the single protective polarizing film, it is possible to effectively generate nanoslits without providing a coating layer. It was found that it can be suppressed. Moreover, when a coating layer is provided between the polarizer and the pressure-sensitive adhesive layer, the generation of nano slits can be more effectively suppressed due to the synergistic effect of the pressure-sensitive adhesive layer and the coating layer.

Moreover, since the adhesive layer of the piece protection polarizing film with an adhesive layer of this invention is adjusted to the said adhesive force, even if it is a case where a thin polarizer is used, the said polarizing film is a glass substrate or glass. It can peel from the ITO film provided on the substrate without breaking.

In the piece protective polarizing film with the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer preferably has a loss elastic modulus peak of −45 ° C. or higher.

Moreover, in the piece protective polarizing film with an adhesive layer, the adhesive layer preferably has a storage elastic modulus at 85 ° C. of 5.5 × 10 ⁴ Pa or more and 1.4 × 10 ⁵ Pa or less.

Moreover, in the said piece protection polarizing film with an adhesive layer, the said adhesive layer contains a (meth) acrylic-type polymer as a base polymer, The said (meth) acrylic-type polymer is as a monomer unit,
Alkyl (meth) acrylate (A) having a glass transition temperature of less than 0 ° C. of homopolymer is 80 wt% or more, and Alkyl (meth) acrylate (b1) and homopolymer having a glass transition temperature of homopolymer of 0 ° C. or more 0.1 to 20 weight percent of at least one high Tg monomer (B) selected from the group consisting of (meth) acryloyl group-containing monomer (b2) having a glass transition temperature of 0 ° C. or higher and a heterocyclic ring % Content is preferable.

The (meth) acrylic polymer is at least one selected from the group consisting of a nitrogen-containing monomer, a carboxyl group-containing monomer, and a hydroxyl group-containing monomer as a monomer unit, and the (meth) acryloyl group It is preferable to contain polar monomers other than the containing monomer (b2).

The nitrogen-containing monomer is preferably a vinyl monomer having a lactam ring. The vinyl monomer having a lactam ring is preferably a vinyl pyrrolidone monomer. The vinyl pyrrolidone monomer is preferably N-vinyl pyrrolidone.

The (meth) acrylic polymer preferably contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit, and preferably contains 0.01 to 2% by weight of the carboxyl group-containing monomer. It is preferable to contain 0.01 to 1% by weight of the hydroxyl group-containing monomer.

It is preferable that the pressure-sensitive adhesive layer contains a rework improver.

The content of the rework improver in the pressure-sensitive adhesive layer is preferably 0.001 to 10 parts by weight with respect to 100 parts by weight of the base polymer that is a material for forming the pressure-sensitive adhesive layer.

In the above-mentioned piece protective polarizing film with an adhesive layer, the polarizer preferably has a thickness of 12 μm or less.

In the piece protective polarizing film with the pressure-sensitive adhesive layer, the polarizer contains a polyvinyl alcohol-based resin, and an optical characteristic represented by a single transmittance T and a polarization degree P is represented by the following formula P> − ( 10 ^0.929T-42.4 -1) x 100 (where T <42.3), or
It is preferable that the lens is configured to satisfy the condition of P ≧ 99.9 (however, T ≧ 42.3).

Moreover, in the piece protective polarizing film with an adhesive layer, the polarizer preferably contains boric acid in an amount of 25% by weight or less based on the total amount of the polarizer.

Moreover, a separator can be provided in the pressure-sensitive adhesive layer of the above-mentioned piece protective polarizing film with a pressure-sensitive adhesive layer. The piece protective polarizing film with an adhesive layer provided with the separator can be used as a wound body.

The present invention also relates to an image display device having the above-mentioned piece protective polarizing film with an adhesive layer.

Further, the present invention provides the adhesive protective layer-attached piece protective polarizing film fed out from the wound body of the adhesive protective layer-attached piece protective polarizing film and transported by the separator of the image display panel via the adhesive layer. The present invention relates to a continuous manufacturing method of an image display device including a step of continuously bonding to a surface.

In the piece protective polarizing film with the pressure-sensitive adhesive layer of the present invention, a pressure-sensitive adhesive layer having a storage elastic modulus at −40 ° C. of 7.0 × 10 ⁷ Pa or more is provided on the polarizer side of the piece protective polarizing film, The pressure-sensitive adhesive layer has a high elastic property when external stress is applied at a high speed (high storage elastic modulus in a low temperature region), so that the polarizing film is difficult to bend when a mechanical shock is applied to the polarizing film at a high speed. . As a result, the generation of nano slits can be effectively suppressed without providing a coating layer. Moreover, since the process which provides a coating layer can abbreviate | omit the process which provides a coating layer, the piece protection polarizing film with an adhesive layer of this invention can improve productivity compared with the conventional thing which provided the coating layer. In addition, the pressure-sensitive adhesive layer of the piece protective polarizing film with a pressure-sensitive adhesive layer of the present invention has a thin polarizer because the adhesive strength to the ITO film surface of the alkali-free glass surface and the glass with the ITO film is adjusted to 8 N / 25 mm or less. Even if it is a case, the said polarizing film can be peeled without fracture | rupture from the glass substrate or the ITO film | membrane provided on the glass substrate.

It is an example of the schematic sectional drawing of the piece protection polarizing film with an adhesive layer of this invention. It is an example of the conceptual diagram which contrasts the nano slit and penetrating crack which arise in a polarizer. It is the schematic explaining the evaluation item which concerns on the nano slit of an Example and a comparative example. It is an example of the photograph which shows the crack produced by the nano slit which concerns on an evaluation of an Example and a comparative example. It is an example of the schematic sectional drawing of the continuous manufacturing system of an image display apparatus.

Hereinafter, the piece protective polarizing film with an adhesive layer of the present invention will be described with reference to FIG. The piece protection polarizing film 11 with an adhesive layer of this invention has the piece protection polarizing film 10 and the adhesive layer 4, for example. The single protective polarizing film 10 has the protective film 2 only on one side of the polarizer 1 as shown in FIG. The polarizer 1 and the protective film 2 are laminated via an adhesive layer 3 (other intervening layers such as a pressure-sensitive adhesive layer and an undercoat layer (primer layer)). In addition, although not shown in figure, the piece protection polarizing film 10 can laminate | stack the said easily bonding layer and an adhesive bond layer by providing an easily bonding layer in the protective film 2, or performing an activation process. Although not shown, a plurality of protective films 2 can be provided. The plurality of protective films 2 can be laminated with an adhesive layer 3 (other intervening layers such as a pressure-sensitive adhesive layer and an undercoat layer (primer layer)).

Moreover, as shown in FIG. 1, the adhesive layer 4 in the piece protective polarizing film 11 with an adhesive layer of this invention is provided in the polarizer 1 side of the piece protective polarizing film 10. Although not shown, a coating layer may be provided between the polarizer 1 and the pressure-sensitive adhesive layer 4. The coating layer is not particularly limited, and for example, a known transparent layer described in Japanese Patent No. 6077618 can be applied. In addition, the separator 5 can be provided in the adhesive layer 4 of the piece protection polarizing film 11 with an adhesive layer of this invention, and the surface protection film 6 can be provided in the other side. In the piece protection polarizing film 11 with an adhesive layer of FIG. 1, the case where both the separator 5 and the surface protection film 6 are provided is shown. The pressure-sensitive adhesive layer-attached piece protective polarizing film 11 having at least the separator 5 (further, having the surface protective film 6) can be used as a wound body, and as described later, for example, is fed out from the wound body, A method (hereinafter also referred to as “roll-to-panel method”) in which the adhesive layer-attached piece protective polarizing film 11 conveyed by the separator 5 is bonded to the surface of the image display panel via the adhesive layer 4. Is advantageous for application to Japanese Patent No. 4406043. The piece protective polarizing film with a pressure-sensitive adhesive layer shown in FIG. 1 is preferably used from the viewpoints of suppressing warpage of the display panel after being bonded and suppressing generation of nanoslits.

FIG. 2 is a conceptual diagram comparing the nano slit a and the through crack b generated in the polarizer. 2A shows a nano slit a generated in the polarizer 1, and FIG. 2B shows a through crack b generated in the polarizer 1. FIG. The nano slit a is generated by mechanical impact and is partially generated in the absorption axis direction of the polarizer 1. The nano slit a cannot be confirmed at the beginning, but is in a thermal environment (for example, 80 ° C. or 60 ° C., 90% RH), it can be confirmed by the spread in the width direction. On the other hand, it is considered that the nano slit a does not have a progressive property extending in the absorption axis direction of the polarizer. Moreover, it is thought that the said nano slit a arises irrespective of the size of a polarizing film. The nano slits a may occur not only independently but also adjacent to each other. On the other hand, the through crack b is generated by a thermal shock (for example, a heat shock test). The through crack has a process of extending in the absorption axis direction of the polarizer where the crack has occurred. When the through crack b is generated, the peripheral stress is released, so that the through crack does not occur adjacently.

<Polarizer>
In the present invention, the thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, still more preferably 8 μm or less, even more preferably 7 μm or less, particularly preferably from the viewpoint of reducing the thickness and preventing the occurrence of through cracks. Is 6 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more. Such a thin polarizer has less thickness unevenness, excellent visibility, and less dimensional change, and therefore excellent durability against thermal shock.

A polarizer using a polyvinyl alcohol resin is used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable.

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

The polarizer preferably contains boric acid from the viewpoint of stretching stability and optical durability. Further, the content of boric acid contained in the polarizer is preferably 25% by weight or less, more preferably 20% by weight or less, based on the total amount of the polarizer, from the viewpoint of suppressing the generation of through cracks and nano slits and suppressing expansion. Preferably, it is 18% by weight or less, and more preferably 16% by weight or less. When the content of boric acid contained in the polarizer exceeds 25% by weight, even if the thickness of the polarizer is reduced (for example, 12 μm or less), the contraction stress of the polarizer is increased and through cracks are likely to occur. Therefore, it is not preferable. On the other hand, from the viewpoint of the stretching stability and optical durability of the polarizer, the boric acid content with respect to the total amount of the polarizer is preferably 10% by weight or more, and more preferably 12% by weight or more.

As a thin polarizer, typically,
Patent No. 4751486,
Japanese Patent No. 4751481,
Patent No. 4815544,
Patent No. 5048120,
Japanese Patent No. 5587517,
International Publication No. 2014/077599 pamphlet,
International Publication No. 2014/077636 Pamphlet,
And the thin polarizers obtained from the production methods described therein.

The polarizer has an optical characteristic expressed by a single transmittance T and a polarization degree P of the following formula P> − (10 ^0.929T-42.4 −1) × 100 (where T <42.3), Or
It is preferably configured to satisfy the condition of P ≧ 99.9 (however, T ≧ 42.3). A polarizer configured so as to satisfy the above-described conditions uniquely has performance required as a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum luminance is 500 cd / m ² or more. As other uses, for example, it is bonded to the viewing side of the organic EL display device.

On the other hand, a polarizer configured to satisfy the above conditions is coupled with a thin film (for example, a thickness of 12 μm or less) because a polymer (for example, a polyvinyl alcohol-based molecule) constituting the polarizer exhibits high orientation. The tensile breaking stress in the direction perpendicular to the absorption axis direction of the polarizer is significantly reduced. As a result, for example, when exposed to a mechanical impact exceeding the tensile breaking stress in the manufacturing process of the polarizing film, there is a very high possibility that nano slits will occur in the absorption axis direction of the polarizer. Therefore, this invention is especially suitable for the piece protection polarizing film (or the piece protection polarizing film with an adhesive layer using the same) which employ | adopted the said polarizer.

As the thin polarizer, among the production methods including the step of stretching in the state of a laminate and the step of dyeing, Patent No. 4751486, Patent, in that it can be stretched at a high magnification and the polarization performance can be improved. What is obtained by the manufacturing method including the process of extending | stretching in a boric-acid aqueous solution as described in the 4751481 specification and the patent 4815544 specification is preferable, and it describes especially in the patent 4751481 specification and the patent 4815544 specification. What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary before extending | stretching in the boric-acid aqueous solution which has this is preferable. These thin polarizers 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.

<Protective film>
As the material constituting the 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 Polymer blends and the like can also be mentioned as examples of the polymer forming the protective film.

In addition, 1 or more types of arbitrary appropriate additives may be contained in the protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a 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 protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When content of the said thermoplastic resin in a protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film, and the like can also be used. 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. In the case where a retardation film is used as the 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 obtained 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 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. In particular, it is preferably 1 to 300 μm, more preferably 5 to 200 μm, and further preferably 5 to 150 μm, particularly 5 to 80 μm.

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 where the polarizer is not adhered. In addition, the hard coat layer, the antireflection layer, the antisticking layer, the diffusion layer, the antiglare layer, and other functional layers can be provided on the protective film itself, or can be provided separately from the protective film. it can.

<Intervening layer>
The protective film and the polarizer are laminated via an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that the both are laminated without an air gap by an intervening layer. The protective film and the polarizer are preferably laminated via an adhesive layer.

The adhesive layer is formed with an adhesive. The type of the 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. Examples of the adhesive include water-based, solvent-based, hot-melt-based, active energy ray-curable types, and the like. Or an active energy ray hardening-type adhesive agent is suitable.

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

The active energy ray curable adhesive is an adhesive that cures by an active energy ray such as an electron beam or ultraviolet rays (radical curable type, cationic curable type), for example, in an electron beam curable type or an ultraviolet curable type. Can be used. As the active energy ray curable adhesive, for example, a photo radical curable adhesive can be used. When the photo radical curable active energy ray curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical polymerizable compound and a photo polymerization initiator.

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.

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

In addition, in laminating | stacking a polarizer and a protective film, an easily bonding layer can be provided between a 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 protective film, and the easy-adhesion layer side of the protective film and the polarizer are laminated with an adhesive layer. The easy-adhesion layer is formed by applying and drying a material for forming the easy-adhesion layer on a 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.

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 adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, Examples include acrylamide-based adhesives and cellulose-based 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 undercoat layer (primer layer) is formed to improve the adhesion between the polarizer and the protective film. The material constituting the primer layer is not particularly limited as long as the material exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin excellent in transparency, thermal stability, stretchability, etc. is used. Examples of the thermoplastic resin include an acrylic resin, a polyolefin resin, a polyester resin, a polyvinyl alcohol resin, or a mixture thereof.

<Adhesive layer>
As described above, the pressure-sensitive adhesive layer in the piece protective polarizing film with the pressure-sensitive adhesive layer of the present invention has a storage elastic modulus at −40 ° C. of 7.0 × 10 ⁷ Pa or more. The storage elastic modulus at −40 ° C. of the pressure-sensitive adhesive layer is preferably 8.0 × 10 ⁷ Pa or more, more preferably 1.0 × 10 ⁷ from the viewpoint of more effectively suppressing the generation of nanoslits. ⁸ Pa or more. On the other hand, the storage elastic modulus at −40 ° C. of the pressure-sensitive adhesive layer is preferably 1.0 × 10 ¹⁰ Pa or less from the viewpoint of preventing peeling that occurs when falling at a low temperature.

In addition, the pressure-sensitive adhesive layer imparts high elastic properties when external stress is applied at high speed, makes the polarizing film difficult to bend, and from the viewpoint of more effectively suppressing the generation of nanoslits, The peak is preferably −45 ° C. or higher, more preferably −40 ° C. or higher, and still more preferably −35 ° C. or higher. On the other hand, from the viewpoint of preventing tackiness from appearing as the pressure-sensitive adhesive layer and preventing it from being used as the pressure-sensitive adhesive layer, the peak of the loss elastic modulus of the pressure-sensitive adhesive layer is usually 0 ° C. or lower.

When manufacturing a liquid crystal panel or using a liquid crystal display device, external stress may be applied to the piece-protecting polarizing film with an adhesive layer at a low speed, and it is preferable to suppress nanoslits generated at that time. From the same viewpoint as the relationship between the storage elastic modulus in the low temperature region of the pressure-sensitive adhesive layer and the number of nanoslits described above, the present inventors have described the storage elastic modulus in the high temperature region of the pressure-sensitive adhesive layer and the nanoslit. As a result of examining the relationship with the number of occurrences, the storage elastic modulus at a high temperature region of the pressure-sensitive adhesive layer, particularly at 85 ° C., and the number of nano-slits when external stress is applied to the piece protective polarizing film with the pressure-sensitive adhesive layer at a low speed We found that there is a correlation. And if the storage elastic modulus in 85 degreeC of an adhesive layer is 5.5x10 < ⁴ > Pa or more, the nanoslit which generate | occur | produces when an external stress will be added to the piece protection polarizing film with an adhesive layer at a low speed will also be suppressed. I found that I can do it. From the viewpoint of further suppressing the nanoslit, the storage elastic modulus at 85 ° C. of the pressure-sensitive adhesive layer is preferably 6.0 × 10 ⁴ Pa or more, more preferably 7.0 × 10 ⁴ Pa or more. On the other hand, when the storage elastic modulus at 85 ° C. of the pressure-sensitive adhesive layer is too high, the pressure-sensitive adhesive layer tends to be peeled off from the polarizer when the size of the polarizer of the one-side protective polarizing film changes due to heat shrinkage. Therefore, the storage elastic modulus at 85 ° C. of the pressure-sensitive adhesive layer is preferably 1.4 × 10 ⁵ Pa or less, more preferably 1.3 × 10 ⁵ Pa or less.

Further, the pressure-sensitive adhesive layer of the piece protective polarizing film with the pressure-sensitive adhesive layer of the present invention has an adhesive force of 8 N / 25 mm or less at a peeling speed of 300 mm / min and a peeling angle of 90 degrees with respect to the alkali-free glass surface, and is a glass with an ITO film. The adhesive strength with respect to the ITO film surface at a peeling speed of 300 mm / min and a peeling angle of 90 degrees is adjusted to 8 N / 25 mm or less. Thereby, even if it is a case where a thin polarizer is used, the said polarizing film can be peeled without fracture | rupture from the ITO film | membrane provided on the glass substrate or the glass substrate. The adhesive strength of the pressure-sensitive adhesive layer to the alkali-free glass surface is preferably 7 N / 25 mm or less, more preferably 6 N / 25 mm or less, and further preferably 5 N / 25 mm or less. Moreover, it is preferable that the adhesive force with respect to the ITO film | membrane surface of the glass with an ITO film | membrane of the said adhesive layer is 7 N / 25mm or less, More preferably, it is 6 N / 25mm or less, More preferably, it is 5 N / 25mm or less.

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, and further preferably 5 to 35 μm.

For the formation of the pressure-sensitive adhesive layer, an appropriate pressure-sensitive adhesive can be used, and the type thereof is not particularly limited. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive adhesives.

Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive pressure characteristics, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics. Hereinafter, a case where an acrylic pressure-sensitive adhesive is used as a material for forming the pressure-sensitive adhesive layer will be described.

As the acrylic pressure-sensitive adhesive, those having a base polymer of a (meth) acrylic polymer having an alkyl (meth) acrylate monomer unit as a main skeleton can be used. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning.

The alkyl group of the alkyl (meth) acrylate composing the main skeleton of the (meth) acrylic polymer has about 1 to 18 carbon atoms. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (Meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, etc. Can, it may be used alone or in combination.

In order to obtain an adhesive layer having the storage elastic modulus, the peak of the loss elastic modulus, and the adhesive force, the (meth) acrylic polymer has a homopolymer glass transition temperature of less than 0 ° C. as a monomer unit (more The alkyl (meth) acrylate (A), which is preferably −20 ° C. or lower, more preferably −40 ° C. or lower) is 80% by weight or more (more preferably 85% by weight or more, more preferably 90% by weight or more), and homo Alkyl (meth) acrylate (b1) having a glass transition temperature of the polymer of 0 ° C. or higher (more preferably 20 ° C. or higher, more preferably 40 ° C. or higher) and a glass transition temperature of the homopolymer of 0 ° C. or higher (more preferably 20 Or higher, more preferably 40 ° C. or higher) and a (meth) acryloyl group-containing monomer (b2) having a heterocyclic ring. 0.1 to 20% by weight (more preferably 1 to 15% by weight, more preferably 2.5 to 10% by weight, and still more preferably 4%) of at least one high Tg monomer (B) selected from the group consisting of (% By weight or more and less than 10% by weight). In addition, when using together the said alkyl (meth) acrylate (b1) and the said (meth) acryloyl group containing monomer (b2), it is weight% in total.

Examples of the alkyl (meth) acrylate (A) include ethyl acrylate (Tg: −24 ° C.), n-butyl acrylate (Tg: −50 ° C.), n-pentyl methacrylate (Tg: −5 ° C.), n- Hexyl acrylate (Tg: -57 ° C), n-hexyl methacrylate (Tg: -5 ° C), n-octyl acrylate (Tg: -65 ° C), n-octyl methacrylate (Tg: -20 ° C), n-nonyl acrylate (Tg: −58 ° C.), n-lauryl acrylate (Tg: −3 ° C.), n-lauryl methacrylate (Tg: −65 ° C.), n-tetradecyl methacrylate (Tg: −72 ° C.), i-propyl acrylate ( Tg: −3 ° C.), i-butyl acrylate (Tg: −40 ° C.), i-octyl acrylate (Tg: −58 ° C.) i- octyl methacrylate (Tg: -45 ℃), 2- ethylhexyl acrylate (Tg: -70 ℃), 2- ethylhexyl methacrylate: include (Tg -10 ° C.) and the like. These can be used alone or in combination. Of these, at least one selected from ethyl acrylate, n-butyl acrylate, n-pentyl methacrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate is preferably used, and n-butyl acrylate is more preferably used. . In addition, Tg (glass transition temperature) in each said parenthesis is Tg of the homopolymer obtained by superposing | polymerizing each monomer. The following description is also the same.

Examples of the alkyl (meth) acrylate (b1) include methyl acrylate (Tg: 8 ° C.), methyl methacrylate (Tg: 105 ° C.), ethyl methacrylate (Tg: 65 ° C.), n-propyl acrylate (Tg: 3 ° C.). ), N-propyl methacrylate (Tg: 35 ° C.), n-pentyl acrylate (Tg: 22 ° C.), n-tetradecyl acrylate (Tg: 24 ° C.), n-hexadecyl acrylate (Tg: 35 ° C.), n- Linear alkyl (meth) acrylates such as hexadecyl methacrylate (Tg: 15 ° C.), n-stearyl acrylate (Tg: 30 ° C.), and n-stearyl methacrylate (Tg: 38 ° C.); t-butyl acrylate (Tg: 43 ° C), t-butyl methacrylate (Tg: 48 ° C), i-propyl methacrylate Branched chain alkyl (meth) acrylates such as acrylate (Tg: 81 ° C.) and i-butyl methacrylate (Tg: 48 ° C.); cyclohexyl acrylate (Tg: 19 ° C.), cyclohexyl methacrylate (Tg: 65 ° C.), isobornyl Examples thereof include cyclic alkyl (meth) acrylates such as acrylate (Tg: 94 ° C.) and isobornyl methacrylate (Tg: 180 ° C.). These can be used alone or in combination. Among these, it is preferable to use at least one selected from methyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl acrylate, and isobornyl methacrylate, and selected from methyl acrylate, methyl methacrylate, and isobornyl acrylate. It is more preferable to use at least one kind.

The (meth) acryloyl group-containing monomer (b2) has a heterocyclic ring. The heterocyclic ring is not particularly limited. And heteroaromatic rings such as thiazole ring, isothiazole ring, pyridine ring, pyrimidine ring, pyridazine ring, and pyrazine ring. The heterocyclic ring may be directly bonded to the (meth) acryloyl group, or may be bonded to the (meth) acryloyl group via a connecting group. Of these, a heteroaliphatic ring is preferable, and a morpholine ring is more preferable. Examples of the (meth) acryloyl group-containing monomer (b2) include N-acryloylmorpholine (Tg: 145 ° C.). These can be used alone or in combination. Of these, it is particularly preferable to use N-acryloylmorpholine.

In the (meth) acrylic polymer, one or more kinds of various monomers can be introduced by copolymerization for the purpose of improving adhesiveness and heat resistance. Specific examples of such copolymerizable monomers (excluding the (meth) acryloyl group-containing monomer (b2)) include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a nitrogen-containing monomer, and an aromatic group-containing monomer. Can be mentioned.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. These can be used alone or in combination.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl (meth) acrylate. Examples thereof include 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) -methyl acrylate. These can be used alone or in combination.

Examples of the nitrogen-containing monomer include vinyl monomers having a lactam ring (eg, vinyl pyrrolidone monomers such as N-vinyl pyrrolidone and methyl vinyl pyrrolidone, and β-lactam rings, δ-lactam rings, and ε-lactam rings). Vinyl lactam monomers having a lactam ring, etc.); maleimide monomers such as maleimide, N-cyclohexylmaleimide, N-phenylmaleimide; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N— Diethyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (Meta (N-substituted) amide monomers such as acrylamide; aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylamino (meth) acrylate (Meth) acrylate aminoalkyl monomers such as ethyl and 3- (3-pyridinyl) propyl (meth) acrylate; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, Succinimide monomers such as N- (meth) acryloyl-8-oxyoctamethylenesuccinimide; Cyano (meth) acrylate monomers such as acrylonitrile and methacrylonitrile; Vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpipe Jin, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, and the like N- vinylcarboxylic acid amides. These can be used alone or in combination.

Examples of the aromatic group-containing monomer include benzyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, and the like. These can be used alone or in combination.

In addition to the above monomers, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrene sulfonic acid and allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid And sulfonic acid group-containing monomers such as (meth) acrylamide propanesulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxynaphthalene sulfonic acid; and phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate. These can be used alone or in combination.

Furthermore, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinylcaprolactam; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; polyethylene glycol (meth) acrylate, ( Glycol acrylic ester monomers such as (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol, (meth) acrylic acid methoxypolypropylene glycol; (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meta ) Acrylic ester monomers such as acrylate and 2-methoxyethyl acrylate can also be used. These can be used alone or in combination.

From the viewpoint of improving the cohesive strength of the (meth) acrylic polymer and more effectively suppressing the generation of the nanoslit, the carboxyl group-containing monomer, the hydroxyl group-containing monomer, and the nitrogen-containing monomer are selected. It is preferable to introduce at least one polar monomer (excluding the (meth) acryloyl group-containing monomer (b2)) into the (meth) acrylic polymer by copolymerization, more preferably the carboxyl group-containing monomer, The hydroxyl group-containing monomer and the nitrogen-containing monomer are introduced into the (meth) acrylic polymer by copolymerization. As the carboxyl group-containing monomer, (meth) acrylic acid is preferable. The hydroxyl group-containing monomer is preferably one or more selected from 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. The nitrogen-containing monomer is preferably a vinyl monomer having a lactam ring, more preferably the vinyl pyrrolidone monomer, and still more preferably N-vinyl pyrrolidone. By introducing the nitrogen-containing monomer into the (meth) acrylic polymer by copolymerization, the generation of nanoslits can be more effectively suppressed and the durability of the pressure-sensitive adhesive layer at high temperatures and / or high humidity Property (peeling resistance) can be improved.

The (meth) acrylic polymer preferably contains 0.01 to 2% by weight of the carboxyl group-containing monomer as a monomer unit, more preferably 0.05 to 1% by weight, and still more preferably 0.0. 1 to 0.3% by weight. By adjusting the content of the carboxyl group-containing monomer within the above range, it is easy to adjust the adhesive strength of the pressure-sensitive adhesive layer to the alkali-free glass surface and the adhesive strength of the glass with ITO film to the ITO film surface to 8 N / 25 mm or less. Become.

The (meth) acrylic polymer preferably contains 0.01 to 1% by weight of the hydroxyl group-containing monomer as a monomer unit, more preferably 0.05 to 1% by weight, and even more preferably 0.1 to 1% by weight. 0.5% by weight. By adjusting the content of the hydroxyl group-containing monomer within the above range, it becomes easy to adjust the adhesive strength of the pressure-sensitive adhesive layer to the non-alkali glass surface and the adhesive strength of the ITO film-attached glass to the ITO film surface to 8 N / 25 mm or less. .

The (meth) acrylic polymer preferably contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit, more preferably 0.5 to 3% by weight, and even more preferably 1.5%. ~ 3% by weight. By adjusting the content of the nitrogen-containing monomer to the above range, it becomes easy to adjust the adhesive strength of the pressure-sensitive adhesive layer to the non-alkali glass surface and the adhesive strength of the ITO film-attached glass to the ITO film surface to 8 N / 25 mm or less. .

The average molecular weight of the (meth) acrylic polymer is not particularly limited, but the weight average molecular weight is preferably about 500,000 to 2.5 million. The (meth) acrylic polymer can be produced by various known methods. For example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo and peroxide initiators can be used. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is 1 to 8 hours. Among the above production methods, the solution polymerization method is preferable, and ethyl acetate, toluene and the like are generally used as the solvent for the (meth) acrylic polymer.

The crosslinking agent can be blended with the adhesive. Adhesion and durability can be improved by the crosslinking agent, and reliability at high temperatures and the shape of the adhesive itself can be maintained. As the cross-linking agent, isocyanate, epoxy, peroxide, metal chelate, oxazoline, and the like can be used as appropriate. These crosslinking agents can be used alone or in combination of two or more.

An isocyanate compound is used as the isocyanate-based crosslinking agent. Isocyanate compounds include isocyanate monomers such as tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and these isocyanates. Adduct isocyanate compounds in which monomers are added with trimethylolpropane, etc .; isocyanurates, burette type compounds, and urethane prepolymers obtained by addition reaction of known polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprene polyols, etc. Examples thereof include polymer type isocyanate.

The isocyanate-based crosslinking agent may be used alone or as a mixture of two or more, but the total content is based on 100 parts by weight of the base polymer. It is preferable to contain 0.01 to 2 parts by weight of a crosslinking agent, more preferably 0.02 to 2 parts by weight, and more preferably 0.05 to 1.5 parts by weight. preferable. It can be appropriately contained in consideration of cohesive force and prevention of peeling in a durability test.

Various peroxides are used as the peroxide-based crosslinking agent. Peroxides include di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate , T-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate, 1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, and the like. Of these, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide, which are particularly excellent in crosslinking reaction efficiency, are preferably used.

The peroxide may be used alone or as a mixture of two or more, but the total content is 100 parts by weight of the base polymer. 0.01 to 2 parts by weight, preferably 0.04 to 1.5 parts by weight, more preferably 0.05 to 1 part by weight. In order to adjust processability, reworkability, cross-linking stability, peelability, and the like, it is appropriately selected within this range.

Furthermore, the pressure-sensitive adhesive can contain a silane coupling agent. The durability can be improved by using a silane coupling agent. As the silane coupling agent, one having any appropriate functional group can be used. Specifically, examples of the functional group include a vinyl group, an epoxy group, an amino group, a mercapto group, a (meth) acryloxy group, an acetoacetyl group, an isocyanate group, a styryl group, and a polysulfide group. Specifically, for example, vinyl group-containing silane coupling agents such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycol Epoxy group-containing silane coupling agents such as sidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N- (1,3-dimethylbutylidene) Propylamine, N-phenyl-γ Amino group-containing silane coupling agents such as aminopropyltrimethoxysilane; γ-mercaptopropylmethyldimethoxysilane and other mercapto group-containing silane coupling agents; p-styryltrimethoxysilane and other styryl group-containing silane coupling agents; (Meth) acrylic group-containing silane coupling agents such as acryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxylane; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; bis (triethoxysilyl) And polysulfide group-containing silane coupling agents such as propyl) tetrasulfide.

The silane coupling agent may be used singly or as a mixture of two or more. However, the total content of the silane coupling agent is 100 parts by weight of the base polymer. The amount 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 preferably 0.05 to 0.6 part by weight.

Furthermore, the pressure-sensitive adhesive preferably contains a rework improver from the viewpoint of improving reworkability. The rework improver is a chemical substance having a polar group, easily interacting with the glass interface, and easily segregating at the glass interface. Examples of the rework improver include diols having an alkyleneoxy group such as EO and PO, oligomers having a perfluoroalkyl group, and polyether compounds having a reactive silyl group. As the polyether compound, for example, those disclosed in JP 2010-275522 A can be used.

Examples of the polyether compound having a reactive silyl group include MS polymer S203, S303, S810 manufactured by Kaneka; SILYLＹEST250, EST280; SAT10, SAT200, SAT220, SAT350, SAT400; Or S3430 etc. are mentioned.

The content of the rework improver is preferably 0.001 part by weight or more, more preferably 0.01 part by weight or more, further preferably 0.1 part by weight or more, with respect to 100 parts by weight of the base polymer. The amount is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, further preferably 2 parts by weight or less, and still more preferably 1 part by weight or less. When the content of the rework improver is less than 0.001 part by weight, the reworkability of the pressure-sensitive adhesive layer is difficult to improve, and when it exceeds 10 parts by weight, the pressure-sensitive adhesive property of the pressure-sensitive adhesive layer tends to deteriorate.

Furthermore, the pressure-sensitive adhesive preferably contains an antistatic agent. At the time of manufacturing the liquid crystal display device, when the piece protective polarizing film with the adhesive layer is attached to the liquid crystal panel, the release film is peeled off from the adhesive layer of the piece protective polarizing film with the adhesive layer. Static electricity is generated by peeling. In addition, when a bonding mistake occurs when the piece protective polarizing film with an adhesive layer is bonded to the liquid crystal panel, the polarizing film needs to be peeled off, but static electricity is generated by peeling off the polarizing film. . The generated static electricity affects the alignment of the liquid crystal inside the liquid crystal display device, leading to defects. Further, display unevenness due to static electricity may occur when the liquid crystal display device is used. By adding an antistatic agent to the pressure-sensitive adhesive, an antistatic function can be imparted to the pressure-sensitive adhesive layer of the piece protective polarizing film with a pressure-sensitive adhesive layer, and these problems can be prevented.

The antistatic agent is not particularly limited, and examples thereof include ionic compounds such as onium-anion salts and alkali metal salts. When an ionic compound is added, it is considered that the antistatic function is efficiently exhibited by bleeding out of the ionic compound on the surface of the pressure-sensitive adhesive layer. On the other hand, when the ionic compound is in contact with the polarizer, optical characteristics such as the degree of polarization may be deteriorated. From the viewpoint of suppressing the deterioration of the optical characteristics, it is particularly preferable to use an alkali metal salt.

As the alkali metal salt, an organic salt or inorganic salt of alkali metal can be used. One alkali metal salt may be used alone, or a plurality of alkali metal salts may be used in combination.

Examples of the alkali metal ions constituting the cation portion of the alkali metal salt include lithium, sodium, and potassium ions. Of these alkali metal ions, lithium ions are preferred.

The anion part of the alkali metal salt may be composed of an organic material or an inorganic material. Examples of the anion part constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , and (CF ₃ SO ₂ ). _{^{_{_{3 C -, C 4 F 9}}}} SO 3 -, (C 2 F 5 SO 2) 2 N -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N -, - O 3 S ( CF ₂ ) ₃ SO ₃ ⁻ , PF ₆ ⁻ , CO ₃ ²⁻ , etc. are used. In particular, an anion moiety containing a fluorine atom is preferably used because an ionic compound having good ion dissociation properties can be obtained. The anion part constituting the inorganic salt includes Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , SbF. ₆ ⁻ , NbF ₆ ⁻ , TaF ₆₋ , (CN) ₂ N ⁻ , and the like are used. The anion moiety is preferably (perfluoroalkylsulfonyl) imide such as (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , and particularly represented by (CF ₃ SO ₂ ) ₂ N ⁻ . (Trifluoromethanesulfonyl) imide is preferred.

Specific examples of the alkali metal organic salt include sodium acetate, sodium alginate, sodium lignin sulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C, KO ₃ S (CF ₂ ) ₃ SO ₃ K, _{_{_{LiO 3 S (CF 2) 3}}} SO 3 K , and the like, among these _{_{_{_{LiCF 3 SO 3, Li (CF}}}} 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 F ₉ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C and the like are preferable, and Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO ₂₎ ₂ Fluorine-containing lithium imide salt is more preferably equal, particularly (perfluoroalkyl sulfonyl) imide lithium salts are preferred.

Also, examples of the alkali metal inorganic salt include lithium perchlorate and lithium iodide.

The content of the alkali metal salt in the pressure-sensitive adhesive is preferably 0.001 to 5 parts by weight with respect to 100 parts by weight of the base polymer. When the alkali metal salt is less than 0.001 part by weight, the effect of improving the antistatic performance may not be sufficient. The alkali metal salt is preferably 0.01 parts by weight or more, and more preferably 0.1 parts by weight or more. On the other hand, if the amount of the alkali metal salt is more than 5 parts by weight, the durability may not be sufficient. The alkali metal salt is preferably 3 parts by weight or less, more preferably 1 part by weight or less.

As a method for forming the pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive is applied to a release-treated separator, and the polymerization solvent is dried and removed to form the pressure-sensitive adhesive layer. In the embodiment of FIG. 1, it is produced by a method of transferring to a polarizer) or a method of applying the pressure-sensitive adhesive and drying and removing the polymerization solvent to form a pressure-sensitive adhesive layer on the polarizer side. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

A silicone release liner is preferably used as the release-treated separator. 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 heating and 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.

Appropriate time can be adopted as the drying time. 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 for 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.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a peeled sheet (separator) 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 about 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.

<Surface protection film>
A surface protective film can be provided in the piece protective polarizing film with an adhesive layer. 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 to 100 μm, preferably 5 to 50 μm.

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. .

<Other optical layers>
The piece protective polarizing film with an 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, the reflective polarizing film or transflective polarizing film in which the reflective plate or the semi-transmissive reflective plate is further laminated on the single protective polarizing film with the pressure-sensitive adhesive layer of the present invention, and the additional retardation to the single-protective polarizing film with the adhesive layer. Brightness is added to the elliptical polarizing film or circular polarizing film in which the plates are laminated, the wide viewing angle polarizing film in which the viewing angle compensation film is further laminated on the piece protective polarizing film with the adhesive layer, or the piece protective polarizing film with the adhesive layer. A polarizing film obtained by laminating an improvement film is preferable.

An optical film obtained by laminating the above optical layer on a piece 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. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. When adhering the above-mentioned piece protective polarizing film with pressure-sensitive adhesive layer and other optical films, their optical axes can be arranged at an appropriate angle depending on the intended retardation characteristics and the like.

The piece protective polarizing film with an adhesive layer or an optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices and organic EL display devices. 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 with an adhesive layer or an optical film, and an illumination system as necessary, and incorporating a drive circuit. In the present invention, there is no particular limitation except that a piece protective polarizing film with an adhesive layer or an optical film according to the present invention is used. As the liquid crystal cell, an arbitrary type such as an IPS type or a VA type can be used, but is particularly suitable for the IPS type.

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.

<Continuous Manufacturing Method for Image Display Device>
Said image display apparatus is the pressure-sensitive adhesive layer with the pressure-sensitive adhesive layer-attached piece protective polarizing film fed out from the wound body (roll) of the pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention. It is preferably manufactured by a continuous manufacturing method (roll-to-panel method) including a step of continuously laminating to the surface of the image display panel via a film. Since the piece protective polarizing film with an adhesive layer of the present invention is a very thin film, it is cut into sheets (sheet-fed cutting) and then bonded to the image display panel one by one ("sheet-to-panel method" ”), It is difficult to handle the sheet when it is transported or bonded to the display panel, and the adhesive protective layer-attached piece protective polarizing film (sheet) has a large mechanical impact (for example, bending due to adsorption). Etc.) The risk of receiving is increased. In order to reduce such a risk, it is necessary to take another measure such as using a thick surface protective film having a thickness of 50 μm or more. On the other hand, according to the roll-to-panel method, the single protective polarizing film with an adhesive layer is not cut into sheets (sheet-fed cutting) and is stably conveyed from the roll to the image display panel by a continuous separator. And since it is affixed on an image display panel as it is, the said risk can be reduced significantly, without using a thick surface protection film. As a result, combined with the ability to relieve mechanical impact by the adhesive layer that is controlled so that the film thickness and storage elastic modulus satisfy a predetermined relational expression, the image display in which the generation of nano slits is effectively suppressed Panels can be produced continuously at high speed.

FIG. 5 is a schematic view showing an example of a continuous manufacturing system of a liquid crystal display device adopting a roll-to-panel method. As shown in FIG. 5, the liquid crystal display device continuous manufacturing system 100 includes a series of transport units X that transport the liquid crystal display panel P, a first polarizing film supply unit 101 a, a first bonding unit 201 a, and a second polarizing film supply. Part 101b and 2nd pasting part 201b are included. In addition, as the wound body (first roll) 20a of the first protective layer-attached piece protective polarizing film and the wound body (second roll) 20b of the second protective layer-attached piece protective polarizing film, it is absorbed in the longitudinal direction. An embodiment having an axis and the embodiment shown in FIG. 1 is used.

(Transport section)
The transport unit X transports the liquid crystal display panel P. The conveyance unit X is configured to include a plurality of conveyance rollers, a suction plate, and the like. The transport unit X is an arrangement in which the placement relationship between the long side and the short side of the liquid crystal display panel P is switched between the first bonding unit 201a and the second bonding unit 201b with respect to the transport direction of the liquid crystal display panel P. A replacement unit (for example, the liquid crystal display panel P is rotated 90 ° horizontally) 300 is included. Thereby, the 1st adhesive layer-attached piece protective polarizing film 21a and the 2nd adhesive layer-attached piece protective polarizing film 21b can be bonded to the liquid crystal display panel P in a crossed Nicols relationship.

(First polarizing film supply unit)
The 1st polarizing film supply part 101a is drawn | fed out from the 1st roll 20a, and the 1st adhesive layer-attached piece protection polarizing film (with surface protection film) 21a conveyed by the separator 5a is continuous to the 1st bonding part 201a. To supply. The first polarizing film supply unit 101a includes a first feeding unit 151a, a first cutting unit 152a, a first peeling unit 153a, a first winding unit 154a, and a plurality of conveying roller units, an accumulating unit such as a dancer roll, and the like. Have.

The first feeding portion 151a has a feeding shaft on which the first roll 20a is installed, and feeds the strip-shaped adhesive layer-attached piece protective polarizing film 21a provided with the separator 5a from the first roll 20a.

The first cutting unit 152a has cutting means and suction means such as a cutter and a laser device. The 1st cutting part 152a cut | disconnects the strip | belt-shaped 1st adhesive layer-attached piece protective polarizing film 21a in the width direction by predetermined length, leaving the separator 5a. However, as the first roll 20a, a strip-shaped adhesive polarizing film 21a with a pressure-sensitive adhesive layer in which a plurality of cut lines are formed in the width direction with a predetermined length is laminated on the separator 5a (optical with cuts) When the film roll is used, the first cutting unit 152a is not necessary (the same applies to the second cutting unit 152b described later).

The 1st peeling part 153a peels the piece protection polarizing film 21a with a 1st adhesive layer from the separator 5a by folding up with the separator 5a inside. Examples of the first peeling portion 153a include a wedge-shaped member and a roller.

The first winding unit 154a winds up the separator 5a from which the first pressure-sensitive adhesive layer-attached piece protective polarizing film 21a has been peeled off. The first winding unit 154a has a winding shaft on which a roll for winding the separator 5a is installed.

(1st bonding part)
The 1st bonding part 201a is the liquid crystal display panel P conveyed by the conveyance part X. The 1st adhesive layer-attached piece protective polarizing film 21a peeled off by the 1st peeling part 153a is the first adhesive layer-attached piece. It bonds together through the adhesive layer of the protective polarizing film 21a (1st bonding process). The 1st bonding part 81 has a pair of bonding rollers, and at least one of the bonding rollers is configured by a drive roller.

(Second polarizing film supply unit)
The 2nd polarizing film supply part 101b is drawn | fed out from the 2nd roll 20b, and the 2nd adhesive part layer-attached piece protection polarizing film (with surface protection film) 21b conveyed by the separator 5b is continuous to the 2nd bonding part 201b. To supply. The second polarizing film supply unit 101b includes a second feeding unit 151b, a second cutting unit 152b, a second peeling unit 153b, a second winding unit 154b, and a plurality of conveying roller units, an accumulating unit such as a dancer roll, and the like. Have. The second feeding portion 151b, the second cutting portion 152b, the second peeling portion 153b, and the second winding portion 154b are respectively the first feeding portion 151a, the first cutting portion 152a, the first peeling portion 153a, and the first winding. It has the same configuration and function as the taking part 154a.

(2nd bonding part)
The 2nd bonding part 201b is the liquid crystal display panel P conveyed by the conveyance part X. The 2nd adhesive layer-attached piece protective polarizing film 21b peeled by the 2nd peeling part 153b is the second adhesive layer-attached piece. It bonds together through the adhesive layer of the protective polarizing film 21b (2nd bonding process). The 2nd bonding part 201b has a pair of bonding rollers, and at least one of the bonding rollers is comprised with a drive roller.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In addition, all the parts and% in each example are based on weight. The room temperature standing conditions not specifically defined below are all 23 ° C. and 65% RH.

<Preparation of single protective polarizing film A>
(Production of polarizer)
One side of an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. is subjected to corona treatment. Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing 9: 1 ratio of the trade name “Gosefimer Z200”) was applied and dried at 25 ° C. to form a PVA-based resin layer having a thickness of 11 μm, thereby preparing a laminate.
The obtained laminate was uniaxially stretched in the longitudinal direction (longitudinal direction) 2.0 times between rolls having different peripheral speeds in an oven at 120 ° C. (air-assisted stretching process).
Next, the laminate was immersed in an insolubilization bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Subsequently, it was immersed in a dyeing bath having a liquid temperature of 30 ° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was blended with 100 parts by weight of water, and immersed in an aqueous iodine solution obtained by blending 1.0 part by weight of potassium iodide (dyeing treatment). .
Subsequently, it was immersed for 30 seconds in a crosslinking bath having a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water). (Crosslinking treatment).
Thereafter, the laminate was immersed in a boric acid aqueous solution (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C. However, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (in-water stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. (cleaning treatment).
Thus, an optical film laminate including a polarizer having a thickness of 5 μm and a boric acid content of 16% was obtained. The boric acid content in the polarizer was measured by the following method.

About the obtained polarizer, boric acid was measured by total reflection attenuation spectroscopy (ATR) measurement using polarized light as measurement light, using a Fourier transform infrared spectrophotometer (FTIR) (manufactured by Perkin Elmer, trade name “SPECTRUM2000”). The intensity of the peak (665 cm ⁻¹ ) and the intensity of the reference peak (2941 cm ⁻¹ ) were measured. The boric acid content index was calculated from the obtained boric acid peak intensity and the reference peak intensity by the following formula, and the boric acid content (% by weight) was determined from the calculated boric acid index by the following formula.
(Boric acid amount index) = (Intensity of boric acid peak 665 cm ⁻¹ ) / (Intensity of reference peak 2941 cm ⁻¹ )
(Boric acid content (% by weight)) = (Boric acid content index) × 5.54 + 4.1

(Preparation of transparent protective film)
Transparent protective film: A (meth) acrylic resin film having a lactone ring structure having a thickness of 40 μm was subjected to corona treatment on the easy adhesion treated surface.

(Preparation of adhesive to be applied to transparent protective film)
An ultraviolet curable adhesive was prepared by mixing 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).

(Preparation of single protective polarizing film A)
After applying the transparent protective film on the surface of the polarizer of the optical film laminate, while applying the UV curable adhesive so that the thickness of the adhesive layer after curing is 0.5 μm, As energy rays, ultraviolet rays were irradiated to cure the adhesive. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, an irradiation device: Fusion UV Systems, Inc. Light HAMMER 10, Inc., bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm) ), And the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Subsequently, the amorphous PET base material was peeled off to produce a piece protective polarizing film A using a thin polarizer. When the single-piece transmittance T and the polarization degree P of the polarizer were measured by the following method using the obtained piece protective polarizing film A, the single-piece transmittance T of the polarizer was 42.8%, and the polarization degree P of the polarizer. Was 99.99%.

The single transmittance T and the polarization degree P of the polarizer of the obtained piece-protecting polarizing film A were measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c, Murakami Color Research Laboratory).
In addition, the polarization degree P is the transmittance (parallel transmittance: Tp) when two identical piece protective polarizing films A are overlapped so that their transmission axes are parallel, and the transmission axes of the two are orthogonal to each other. Thus, the transmittance (orthogonal transmittance: Tc) in the case of superposition is obtained by applying to the following equation. Polarization degree P (%) = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100
Each transmittance is represented by a Y value obtained by correcting visibility with a two-degree field of view (C light source) of JIS Z8701, with 100% of the completely polarized light obtained through the Granteller prism polarizer.

<Preparation of single protective polarizing film B>
A polyvinyl alcohol film having a thickness of 80 μm was stretched up to 3 times while being dyed for 1 minute in an iodine solution of 0.3% concentration at 30 ° C. between rolls having different speed ratios. Thereafter, the film was stretched so that the total stretching ratio was 6 times while being immersed in an aqueous solution containing 60% at 4 ° C., 4% strength boric acid and 10% strength potassium iodide for 0.5 minutes. Next, the film was washed by immersing it in an aqueous solution containing 1.5% potassium iodide at 30 ° C. for 10 seconds, followed by drying at 50 ° C. for 4 minutes to obtain a polarizer having a thickness of 20 μm. It was. A saponified 40 μm acrylic resin film (transparent protective film) was bonded to one surface of the polarizer with an adhesive to produce a single protective polarizing film B.

<Formation of adhesive layer>
(Preparation of acrylic adhesive A)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 91.8 parts of n-butyl acrylate, 6 parts of methyl methacrylate, 1.5 parts of N-vinyl pyrrolidone, 0.2% of acrylic acid And a monomer mixture containing 0.5 parts of 4-hydroxybutyl acrylate. Further, 0.15 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged with ethyl acetate to 100 parts of the monomer mixture (solid content), 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. Thereafter, an acrylic polymer solution having a weight average molecular weight of 1.3 million was prepared by adding ethyl acetate to the obtained reaction solution to adjust the solid content concentration to 20%.

The weight average molecular weight (Mw) of the acrylic polymer was measured using a GPC apparatus (HLC-8220 GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.
Sample concentration: 0.2% by mass (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
Column: Sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1 piece)
Detector: Differential refractometer (RI)
The weight average molecular weight was determined in terms of polystyrene.

0.17 parts of an isocyanate-based cross-linking agent (trade name “Takenate D160N” manufactured by Mitsui Chemicals, Inc.) and a peroxide-based cross-linking agent (manufactured by NOF Corporation, products) with respect to 100 parts of the solid content of the prepared acrylic polymer solution Acrylic pressure-sensitive adhesive A was prepared by blending 0.25 parts of the name “Nyper BMT”) and 0.2 parts of an acetoacetyl group-containing silane coupling agent (manufactured by Soken Chemical Co., Ltd., trade name “A-100”). did.

(Preparation of acrylic adhesives BX)
In the preparation of the acrylic adhesive A, an acrylic polymer solution was prepared in the same manner except that the monomer composition was changed as shown in Table 1 and the polymerization conditions were adjusted. Was prepared. For acrylic adhesives F, G, and OU, a rework improver (trade name “SAT10” manufactured by Kaneka Corporation) is further added to 100 parts of the solid content (acrylic polymer) of the acrylic polymer solution. 0.25 part or 0.1 part was added.

(Formation of adhesive layers A to X)
Next, the prepared acrylic pressure-sensitive adhesives A to X were uniformly applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone-based release agent using a fountain coater, and the air circulation type thermostatic oven at 155 ° C. And dried for 1 minute to form adhesive layers A to X having a thickness of 20 μm on the surface of each separator film.

The compounds in Table 1 are as follows.
BA: n-butyl acrylate (Tg: -50 ° C)
MMA: Methyl methacrylate (Tg: 105 ° C)
MA: methyl acrylate (Tg: 8 ° C.)
IBXA: Isobornyl acrylate (Tg: 94 ° C.)
ACMO: N-acryloylmorpholine (Tg: 145 ° C.)
NVP: N-vinylpyrrolidone AA: acrylic acid 4HBA: 4-hydroxybutyl acrylate

Examples 1 to 22, Comparative Examples 1 to 4
<Preparation of a piece protective polarizing film with an adhesive layer>
The produced pressure-sensitive adhesive layers A to X were bonded to the polarizer side of the produced piece-protected polarizing film A or B, respectively, to produce a piece-protected polarizing film with a pressure-sensitive adhesive layer.

The following measurement and evaluation were performed on the pressure-sensitive adhesive layer and the piece protective polarizing film with the pressure-sensitive adhesive layer obtained above. The results are shown in Table 2.

<Measurement of storage elastic modulus and loss elastic modulus peak>
The storage elastic modulus and loss elastic modulus peaks of the produced pressure-sensitive adhesive layers A to X at −40 ° C. and 85 ° C. were measured using a rheometric viscoelastic spectrometer (trade name: RSA-II). It was. The measurement conditions were a frequency of 1 Hz, a sample thickness of 2 mm, a pressure bonding load of 100 g, a heating rate of 5 ° C./min, and a temperature range of −70 ° C. to 150 ° C.

<Inhibition of nano slit generation: Guitar pick test>
Sample 11 was prepared by cutting the piece protective polarizing film with pressure-sensitive adhesive layer obtained in Examples and Comparative Examples into a size of 50 mm × 150 mm (absorption axis direction was 50 mm). The sample 11 was used by bonding the surface protective film 6 produced by the following method to the protective film 2 side.

(Surface protection film for testing)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 94 parts by mass of 2-ethylhexyl acrylate (2EHA), 1 part by mass of N, N-diethylacrylamide (DEAA), ethoxydiethylene glycol acrylate ( EDE) 1 part by weight, 4-hydroxybutyl acrylate (HBA) 4 parts by weight, 2,2′-azobisisobutyronitrile 0.2 part by weight as a polymerization initiator, ethyl acetate 150 parts by weight, and gently stirring While introducing nitrogen gas, the temperature of the liquid in the flask was kept at around 60 ° C. to conduct a polymerization reaction for 5 hours to prepare an acrylic polymer solution (40% by mass). The acrylic polymer had a weight average molecular weight of 570,000 and a glass transition temperature (Tg) of −68 ° C.
The acrylic polymer solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate) is added to 500 parts by mass (100 parts by mass of solid content) of this solution. HX: C / HX) 2 parts by mass (solid content 2 parts by mass) and 2 parts by mass (solid content 0.02 parts by mass) of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst were added and mixed and stirred. Acrylic pressure-sensitive adhesive solution was prepared.
The acrylic pressure-sensitive adhesive solution is applied to a transparent polyethylene terephthalate (PET) film (polyester film) with a thickness of 38 μm and heated at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer with a thickness of 15 μm to protect the surface. A film was prepared.

Next, as shown in the conceptual diagram of FIG. 3A and the cross-sectional view of FIG. 3B, the release sheet (separator) is peeled from the sample 11, and the glass plate 20 is interposed through the exposed adhesive layer 4. Pasted on top. Next, a load of 200 g is applied to the central portion of the sample 11 (surface protective film 6 side) by a guitar pick (manufactured by HISTROY, model number “HP2H (HARD)”), and the absorption axis of the polarizer 1 in the sample 11 is applied. The load load of 50 reciprocations was repeated at a distance of 100 mm in the orthogonal direction. The load was applied at one place. The load was applied at high speed (5 m / min) and low speed (1 m / min).
Next, after the sample 11 was left in an environment of 80 ° C. for 1 hour, the presence or absence of light leakage cracks in the sample 11 was confirmed according to the following criteria.
(High speed)
◎: 0 to 10 ○: 11 to 15 △: 16 to 30 ×: 31 or more (in the case of low speed)
◎: 0 ○ ○: 1 to 3 △: 4 to 5 ×: 6 or more

FIG. 4 is an example of a photograph of a microscope on the surface of the polarizing film, which serves as the following index for confirming a crack in light leakage (nano slit a) in the guitar pick test of the piece protective polarizing film 11 with an adhesive layer. In FIG. 4A, no light leakage crack due to the nano slit a is confirmed. On the other hand, FIG. 4B shows a case in which three light cracks due to the nano slit a are generated in the absorption axis direction of the polarizer by heating. In FIG. 4, the sample in which the nano slit was generated was observed with a differential interference microscope. When the sample was photographed, the sample without nano slits was set to cross Nicole on the lower side (transmission light source side) of the sample where nano slits were generated and observed with transmitted light. .

<Evaluation of adhesive strength>
A sample obtained by cutting the produced polarizing film with an adhesive layer into a length of 120 mm and a width of 25 mm was used as a sample. After the sample was attached to a non-alkali glass plate with a thickness of 0.7 mm (EG-XG, manufactured by Corning) using a laminator, and then autoclaved at 50 ° C. and 5 atm for 15 minutes for complete adhesion. The adhesive strength of the sample was measured. The adhesive strength is measured by peeling the sample with a tensile tester (Autograph SHIMAZU AG-1 1OKN) at a peeling angle of 90 ° and a peeling speed of 300 mm / min (N / 25 mm, measuring length 80 mm). Was determined by The measurement was sampled 200 times at an interval of 1 time / 0.5 s, and the average value was taken as the measured value. The number of specimens was 3 specimens.
Similarly, the sample was attached to an ITO film of an ITO glass plate having a thickness of 0.7 mm using a laminator, and then autoclaved at 50 ° C. and 5 atm for 15 minutes to completely adhere the sample. The adhesive strength was measured by the same method as described above. The ITO glass plate used was obtained by forming an amorphous ITO film on the alkali-free glass plate used as an adherend in the measurement of the adhesive strength of the alkali-free glass. The amorphous ITO film was formed by sputtering. The composition of the amorphous ITO film was an Sn ratio of 3% by weight, and a heating step of 140 ° C. × 60 minutes was performed before bonding the samples. The Sn ratio of the amorphous ITO film was calculated from the weight of Sn atoms / (weight of Sn atoms + weight of In atoms). And it evaluated by the following reference | standard.
◎: 5N / 25mm or less ○: 5N / 25mm or more 7N / 25mm or less △: 7N / 25mm or more 8N / 25mm or less ×: 8N / 25mm or less

<Evaluation of reworkability>
The produced piece protective polarizing film with pressure-sensitive adhesive layer was cut into 32 inches and used as a sample. The sample is attached to each of the ITO film of the alkali-free glass plate and the ITO glass plate used in the measurement of the adhesive force using a laminator, and then autoclaved at 50 ° C. and 5 atm for 15 minutes to be completely adhered. It was. Then, using a rework apparatus, the success rate when reworking was performed under the conditions of a peeling angle of 90 ° and a peeling speed of 300 mm / min. The number of specimens was 4 specimens. And it evaluated by the following reference | standard.
A: Rework 100%
○: Rework 75% or more △: Rework 50% or more ×: Rework 25% or less

<Durability evaluation>
The separator film of the piece protective polarizing film with an adhesive layer (37 inches) was peeled off and attached to a non-alkali glass having a thickness of 0.7 mm (EG-XG, manufactured by Corning) using a laminator. Subsequently, an autoclave treatment was performed at 50 ° C. and 0.5 MPa for 15 minutes, and the polarizing film was completely adhered to the non-acrylic glass. Next, this was put in the conditions of a heating oven (heating) at 80 ° C. and a constant temperature and humidity machine (humidification) at 60 ° C./90% RH, respectively, and the presence or absence of peeling of the polarizing plate after 500 hours was determined as follows: Evaluated by criteria.
A: No peeling was observed.
○: Peeling that was not visually confirmed was observed.
(Triangle | delta): The small peeling which can be confirmed visually is recognized.
X: Clear peeling was recognized.

From Table 2, the piece protective polarizing films with pressure-sensitive adhesive layers of Examples 1 to 22 are less prone to cracking when loaded at high speed or loaded at low speed. It can be seen that the reworkability is good for both the ITO film surface and the ITO film surface, and the durability (peeling resistance) at high temperature and high humidity is excellent. On the other hand, it can be seen that in the piece protective polarizing films with pressure-sensitive adhesive layers of Comparative Examples 1, 2, and 4, many cracks are generated even when a load is applied at a high speed or when a load is applied at a low speed. Moreover, it turns out that the piece protection polarizing film with an adhesive layer of the comparative example 3 has bad rework property with respect to the ITO film | membrane surface. In addition, it can be seen that the reworkability is improved in the piece protective polarizing films with pressure-sensitive adhesive layers of Examples 6, 7, and 12 to 18 in which a rework improver is blended in the pressure-sensitive adhesive layer. Moreover, when the piece protective polarizing film with an adhesive layer of Example 7 and the piece protective polarizing film with an adhesive layer of Example 18 were compared, the adhesive was obtained using an acrylic polymer containing a nitrogen-containing monomer as a monomer unit. It can be seen that the piece-protective polarizing film with a pressure-sensitive adhesive layer of Example 7 in which the layer was formed is less susceptible to cracking and is more excellent in durability (peeling resistance) at high temperatures and high humidity. Moreover, from Example 15 and Example 22, the piece protective polarizing film with the pressure-sensitive adhesive layer of the present invention is less prone to cracks and has good reworkability regardless of whether the polarizer is thin or thick. I understand.

The piece protective polarizing film with a pressure-sensitive adhesive layer of the present invention is used for an image display device such as a liquid crystal display device (LCD) or an organic EL display device as a single or a laminated optical film.

DESCRIPTION OF SYMBOLS 1 Polarizer 2 Protective film 3 Adhesive layer etc. 4

Adhesive layers

5, 5a,

5b Separator

6, 6a, 6b Surface protective film 10 Single protective polarizing film 11 Single protective polarizing film with

adhesive layer

20a, 20b With adhesive layer Single protective polarizing film roll (roll)
21a, 21b Single protective polarizing film with adhesive layer (with surface protective film)
DESCRIPTION OF SYMBOLS 100 Continuous display system of

image display apparatus

101a, 101b Polarizing

film supply part

151a, 151b

Feeding part

152a,

152b Cutting part

153a, 153b

Peeling part

154a,

154b Winding part

201a, 201b Pasting part 300 Arrangement | positioning replacement part P Image display panel X Image display panel transport section

Claims

A piece protective polarizing film with a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer directly or through a coating layer on the polarizer side of the piece protective polarizing film, and a piece protective polarizing film having a protective film only on one side of the polarizer,
The pressure-sensitive adhesive layer has a storage elastic modulus at −40 ° C. of 7.0 × 10 7 Pa or more,
The pressure-sensitive adhesive layer has a peel rate of 300 N / min and a peel angle of 90 degrees with respect to the alkali-free glass surface of 8 N / 25 mm or less, and the pressure-sensitive adhesive layer has a peel rate with respect to the ITO film surface of the glass with ITO film. Adhesive strength at 300 mm / min and peel angle of 90 degrees is 8 N / 25 mm or less.
2. The piece protective polarizing film with an adhesive layer according to claim 1, wherein the adhesive layer has a peak loss elastic modulus of −45 ° C. or more.
The adhesive layer-attached piece protection according to claim 1, wherein the adhesive layer has a storage elastic modulus at 85 ° C. of 5.5 × 10 4 Pa or more and 1.4 × 10 5 Pa or less. Polarized film.
The pressure-sensitive adhesive layer contains a (meth) acrylic polymer as a base polymer, the (meth) acrylic polymer as a monomer unit,
Alkyl (meth) acrylate (A) having a glass transition temperature of less than 0 ° C. of homopolymer is 80 wt% or more, and Alkyl (meth) acrylate (b1) and homopolymer having a glass transition temperature of homopolymer of 0 ° C. or more 0.1 to 20 weight percent of at least one high Tg monomer (B) selected from the group consisting of (meth) acryloyl group-containing monomer (b2) having a glass transition temperature of 0 ° C. or higher and a heterocyclic ring The piece protective polarizing film with an adhesive layer according to any one of claims 1 to 3, wherein
The (meth) acrylic polymer is at least one selected from the group consisting of a nitrogen-containing monomer, a carboxyl group-containing monomer, and a hydroxyl group-containing monomer as a monomer unit, and the (meth) acryloyl group-containing monomer (b2 A polar monomer other than) is contained, and the piece protective polarizing film with an adhesive layer according to claim 4.
6. The piece protective polarizing film with an adhesive layer according to claim 5, wherein the nitrogen-containing monomer is a vinyl monomer having a lactam ring.
The piece protective polarizing film with an adhesive layer according to claim 6, wherein the vinyl monomer having a lactam ring is a vinyl pyrrolidone monomer.
The piece protective polarizing film with an adhesive layer according to claim 7, wherein the vinyl pyrrolidone monomer is N-vinyl pyrrolidone.
9. The piece protective polarizing plate with an adhesive layer according to claim 5, wherein the (meth) acrylic polymer contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit. the film.
10. The piece protection with an adhesive layer according to claim 5, wherein the (meth) acrylic polymer contains 0.01 to 2% by weight of the carboxyl group-containing monomer as a monomer unit. Polarized film.
11. The piece protective polarizing plate with an adhesive layer according to claim 5, wherein the (meth) acrylic polymer contains 0.01 to 1% by weight of the hydroxyl group-containing monomer as a monomer unit. the film.
The piece protective polarizing film with an adhesive layer according to any one of claims 1 to 11, wherein the adhesive layer contains a rework improver.
The content of the rework improver in the pressure-sensitive adhesive layer is 0.001 to 10 parts by weight with respect to 100 parts by weight of a base polymer that is a material for forming the pressure-sensitive adhesive layer. The piece protection polarizing film with an adhesive layer of description.
14. The piece protective polarizing film with an adhesive layer according to claim 1, wherein the polarizer has a thickness of 12 μm or less.
The polarizer contains a polyvinyl alcohol-based resin, and has an optical characteristic represented by a single transmittance T and a polarization degree P of the following formula: P> − (10 0.929T-42.4 −1) × 100 (Where T <42.3), or
15. The piece-protecting polarized light with pressure-sensitive adhesive layer according to claim 1, wherein the piece-protecting polarized light with an adhesive layer is configured to satisfy a condition of P ≧ 99.9 (where T ≧ 42.3). the film.
The piece protective polarizing film with an adhesive layer according to any one of claims 1 to 15, wherein the polarizer contains boric acid in an amount of 25% by weight or less based on the total amount of the polarizer.
The strip protective polarizing film with an adhesive layer according to any one of claims 1 to 16, wherein a separator is provided on the adhesive layer.
It is a wound body, The piece protective polarizing film with an adhesive layer of Claim 17 characterized by the above-mentioned.
An image display device comprising the piece protective polarizing film with an adhesive layer according to any one of claims 1 to 16.
An image display panel comprising the pressure-sensitive adhesive layer-attached piece protective polarizing film fed from the wound body of the pressure-sensitive adhesive layer-attached piece protective polarizing film according to claim 18 and conveyed by the separator. A method for continuously producing an image display device, comprising a step of continuously bonding the surface of the image display device.