KR102444055B1 - Polarizing plate, liquid crystal display and organic electroluminescent display - Google Patents

Abstract

The present invention does not cause light leakage even when exposed to high temperature and high humidity conditions, and suppresses the occurrence of poor appearance such as cracks in the polarizer under an environment such as repeating high temperature and low temperature, and is thin, and It makes it a subject to provide the polarizing plate excellent in intensity|strength. The polarizing plate is a polarizing plate having a polarizer, a protective film, and an adhesive layer, and the dimensional change rate after 1 hour of the protective film in a direction parallel to the direction of the transmission axis of the polarizer under the condition of 85°C and 5% relative humidity. Let the dimensional change rate of the protective film (85 ° C.), and the dimensional change rate of the protective film in a direction parallel to the transmission axis direction of the polarizer, after 0.5 hours under the condition of 30 ° C. and 95% relative humidity of the protective film When it is set as dimensional change rate (30 degreeC), it is a polarizing plate whose absolute value of the difference of the dimensional change rate (85 degreeC) of the said protective film and the dimensional change rate (30 degreeC) of the said protective film is 0.02-0.50.

Description

Polarizing plate, liquid crystal display and organic electroluminescent display

The present invention relates to a polarizing plate that can be used for various optical applications. Further, the present invention relates to a liquid crystal display device and an organic electroluminescence display device having this polarizing plate.

DESCRIPTION OF RELATED ART A polarizing plate is widely used as a polarization|polarized-light supply element in display apparatuses, such as a liquid crystal display device, and also as a polarization|polarized-light detection element. The polarizer formed by extending|stretching and dyeing|dyeing a polyvinyl alcohol film is employ|adopted suitably for such a polarizing plate.

A polarizing plate with few cracks (cracks) of a polarizer is disclosed by patent document 1 (Unexamined-Japanese-Patent No. 2012-145645), so that the linear expansion of a protective film is smaller than the linear expansion of the transmission axis direction of a polarizer. According to patent document 1, evaluation regarding the crack (crack) of a polarizer is made|formed by the test (heat shock acceleration test) which repeats the process of simply heating and lowering a polarizing plate between -40 degreeC and 85 degreeC. Such evaluation by linear expansion described in Patent Document 1 is a parameter generally dependent on temperature.

Moreover, a thin polarizing plate is calculated|required in recent years, and there exists a request|requirement of making a polarizer thin.

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-145645

However, the polarizer manufactured by stretching has a problem that cracks (cracks) are likely to occur along the stretching axis direction. and optical problems such as light leakage. Since the crack of a polarizer is becoming more easy to generate|occur|produce with thinning of a polarizing plate in recent years, a solution is calculated|required.

Moreover, since the polarizer containing polyvinyl alcohol has low tolerance with respect to humidity, use in high humidity conditions is restrict|limited.

For example, in the invention described in Patent Document 1, evaluation by linear expansion is performed. However, in general, since the evaluation method by linear expansion is a parameter dependent on temperature, in Cited Document 1, the relationship between cracks (cracks) and humidity of the polarizer is not considered at all.

Moreover, in order to satisfy the request|requirement of making a polarizing plate thin, when a polarizer is made thin, for example, when a flaw generate|occur|produces on the surface of a protective film, a crack may generate|occur|produce also in a thin film type polarizer.

An object of the present invention is to provide a polarizing plate in which light leakage does not occur even when exposed to high temperature and high humidity conditions. Moreover, an object of this invention is to provide the polarizing plate by which generation|occurrence|production of the appearance defect, such as a crack generate|occur|produced in a polarizer, in an environment like high temperature and low temperature being repeated is suppressed.

The present invention includes the following.

[1] A polarizing plate having a polarizer, a protective film, and an adhesive layer, comprising:

The rate of dimensional change of the protective film in a direction parallel to the direction of the transmission axis of the polarizer after 1 hour has elapsed under the condition of 85 ° C. and 5% of relative humidity is defined as the rate of dimensional change of the protective film (85 ° C.);

When the rate of dimensional change of the protective film in a direction parallel to the direction of the transmission axis of the polarizer after 0.5 hours has elapsed under the conditions of 95% relative humidity at 30°C, the rate of dimensional change (30°C) of the protective film,

A polarizing plate having an absolute value of 0.02 to 0.50 of a difference between a dimensional change rate (85° C.) of the protective film and a dimensional change rate (30° C.) of the protective film.

[2] Let the rate of dimensional change of the polarizer after 1 hour in the transmission axis direction of the polarizer at 85°C under the condition of 5% relative humidity be the rate of dimensional change of the polarizer (85°C);

Let the rate of dimensional change of the polarizer in the transmission axis direction of the polarizer after 0.5 hours under the condition of 95% relative humidity at 30 °C be the rate of dimensional change of the polarizer (30 °C);

Let the absolute value of the difference between the dimensional change rate (85°C) of the polarizer and the dimensional change rate (30°C) of the polarizer be F _PZ ,

Let the absolute value of the difference between the dimensional change rate (85°C) of the protective film and the dimensional change rate (30°C) of the protective film be F _PF ,

A difference obtained by subtracting the F _PF from the F _PZ is ΔF _TD , and

The polarizing plate according to [1], wherein the ratio of ΔF _TD to F _PZ (ΔF _TD /F _PZ ) is in the range of 0.5 to 0.95.

[3] The polarizing plate according to [1] or [2], wherein the polarizer, the protective film, and the pressure-sensitive adhesive layer are disposed in this order.

[4] The polarizing plate according to [1] or [2], wherein the protective film, the polarizer, and the pressure-sensitive adhesive layer are disposed in this order.

[5] The protective film is a cellulose ester-based resin; polyester-based resin; polycarbonate-based resin; (meth)acrylic resin; Or the polarizing plate according to any one of [1] to [4], which is a transparent resin film composed of a mixture of at least two or more thereof.

[6] A liquid crystal display device in which the polarizing plate according to any one of [1] to [5] is laminated on a liquid crystal cell via the pressure-sensitive adhesive layer.

[7] An organic electroluminescent display device in which the polarizing plate according to any one of [1] to [5] is laminated on an organic electroluminescent display via the pressure-sensitive adhesive layer.

ADVANTAGE OF THE INVENTION According to this invention, even if it is a high temperature condition and a high humidity condition, the crack and the crack which generate|occur|produce in a polarizer are suppressed, and the polarizing plate excellent in durability is provided. In addition, even under an environment where high and low temperatures are repeated, and even under an environment where dew condensation occurs, the polarizing plate of the present invention can exhibit good polarization characteristics without causing light leakage or cracking of the polarizer. have. Therefore, the polarizing plate of this invention can be used without generating light leakage, cracks, etc. also under various conditions, such as a high temperature condition and a high humidity condition which could not be applied conventionally.

Moreover, according to this invention, even when a polarizer can be made thin and a flaw generate|occur|produces on the surface of a protective film, the crack of a polarizer can be suppressed. Therefore, the polarizing plate of this invention is thin, and is a polarizing plate excellent in intensity|strength and durability.

Fig. 1 (a) is a schematic cross-sectional view showing an example of the layer configuration of the polarizing plate according to the present invention, and Fig. 1 (b) is a schematic cross-sectional view showing another example of the layer configuration of the polarizing plate according to the present invention.
Fig. 2(a) is a schematic plan view showing an axial angle between a transmission axis and an absorption axis in a polarizing plate having a transmission axis (solid line) in the width direction, and Fig. 2(b) is a transmission axis in a long direction. It is a schematic plan view which shows the axial angle of the transmission axis and the absorption axis in the polarizing plate which has (solid line).
It is a schematic sectional drawing which shows an example of the layer structure of the polarizing plate which concerns on this invention, and a polarizing plate laminated glass substrate.

Hereinafter, although the polarizing plate which concerns on this invention is suitably demonstrated using drawings, this invention is not limited to these embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It shows the schematic sectional drawing of the example of the preferable layer structure in the polarizing plate which concerns on this invention. In FIG. 1( a ), the polarizing plate 100 is a laminate of a polarizer 11 , a protective film 12 , and an adhesive layer 13 . Similarly in FIG. Thus, in this invention, the lamination|stacking order of a polarizer, a protective film, and an adhesive layer is not specifically limited.

The polarizer in the present invention is a member having a function of converting light such as natural light into linearly polarized light, and the polarizer generally has a transmission axis and an absorption axis. The direction of the transmission axis of such a polarizer is understood as a vibration direction of transmitted light when natural light is transmitted through the polarizer. On the other hand, the absorption axis of the polarizer is orthogonal to the transmission axis of the polarizer. Further, the polarizer may be generally a stretched film, and the absorption axis direction of the polarizer coincides with the stretching direction.

In the present invention, the term "direction parallel to the transmission axis direction of the polarizer" indicates a direction parallel to or substantially parallel to the transmission axis direction of the polarizer described above (the forming angle is within ±7 degrees).

In the present invention, the rate of dimensional change after 1 hour has elapsed under the condition of 85°C relative humidity of 5% is measured according to the following formula. On the other hand, the dimensional change rate (85 degreeC) may describe the dimensional change rate after 1 hour pass under the conditions of 85 degreeC relative humidity 5%.

For example, in the present invention, the rate of dimensional change of the protective film in a direction parallel to the direction of the transmission axis of the polarizer at 85°C under the condition of 5% relative humidity for 1 hour is the dimensional change rate of the protective film (85°C). write it as

In addition, the dimensional change rate (85 degreeC) of a polarizer describes the dimensional change rate after 1 hour progress on the conditions of 85 degreeC relative humidity 5% in the transmission axis direction of a polarizer.

Hereinafter, for explanation, the dimensional change rate (85°C) of the protective film and the dimensional change rate (85°C) of the polarizer may be simply described as the dimensional change rate (85°C).

Dimensional change rate (85℃)=[(L0-L85)/L0]×100

[Wherein, L0 means the film dimension of the cut film in the direction parallel to the transmission axis direction of the polarizer (long direction or width direction),

L85 means the film dimension in the direction (long direction or width direction) parallel to the transmission axis direction of the polarizer after 1 hour has elapsed under the condition of 85°C and 5% relative humidity.]

For example, when the film is cut and the dimension (L0) in the width direction is measured, even after standing still for 1 hour under the condition of 85°C and 5% relative humidity, the dimension (L85) in the width direction of the film is measured , calculate the dimensional change rate. In addition, when the dimension (L0) of the direction parallel to the transmission axis direction of the polarizer in the protective film obtained by removing a polarizer etc. from a polarizing plate is measured after manufacturing a polarizing plate, under the conditions of 85 degreeC relative humidity of 5%, Also after leaving still for time, the dimension L85 of the direction parallel to the transmission axis direction of a polarizer is measured, and a dimensional change rate is computed.

The dimensional change rate (85°C) calculated in this way may represent either a positive value (ie, shrinkage) or a negative value (ie, expansion). The protective film whose dimensional change rate (85 degreeC) is a positive value includes, for example, polyolefin resin selected from chain polyolefin resin and cyclic polyolefin resin; Cellulose ester-based resin selected from cellulose triacetate and cellulose diacetate; It is composed of a (meth)acrylic resin selected from polymethyl methacrylate resin (PMMA resin) and the like.

Similarly to the above, in the present invention, the calculation of the dimensional change rate after 0.5 hours has elapsed under the conditions of 30°C relative humidity 95% is measured according to the following formula for the film after measuring the dimensional change rate (85°C) do. On the other hand, the dimensional change rate (30 degreeC) may describe the dimensional change rate after 0.5 hour pass under the conditions of 30 degreeC relative humidity 95%.

For example, in the present invention, the rate of dimensional change of the protective film in a direction parallel to the direction of the transmission axis of the polarizer after 0.5 hours has elapsed under the condition of 95% of relative humidity at 30°C is the rate of dimensional change of the protective film (30 °C) is sometimes described. On the other hand, the rate of dimensional change in a direction parallel to the direction of the transmission axis of the polarizer after 0.5 hours has elapsed under the condition of 95% relative humidity at 30°C is sometimes described as the rate of dimensional change of the polarizer (30°C).

Hereinafter, for explanation, the dimensional change rate (30°C) of the protective film and the dimensional change rate (30°C) of the polarizer may be simply described as the dimensional change rate (30°C).

Dimensional change rate (30℃)=[(L030-L30)/L0]×100

[wherein, L030 means the film dimension after measuring the dimensional change rate (85 ° C.) in the direction parallel to the transmission axis direction of the polarizer (long direction or width direction),

L30 means the film dimension in the direction parallel to the transmission axis direction of the polarizer (long direction or width direction) after 0.5 hours under the condition of 30°C and 95% relative humidity.]

For example, after measuring the dimensional change rate (85° C.), it is allowed to stand for 15 minutes at a temperature of 23° C. and a humidity of 55%, and then L030 can be measured.

The dimensional change rate (30°C) calculated in this way may represent either a positive value (ie, shrinkage) or a negative value (ie, expansion). The protective film whose dimensional change rate (30 degreeC) is a positive value, For example, Polyolefin resins, such as a chain|strand polyolefin resin and cyclic polyolefin resin; It is composed of a polyester-based resin, such as polyethylene terephthalate.

On the other hand, the protective film whose dimensional change rate (30°C) is a negative value (expands) is, for example, a cellulose ester-based resin such as cellulose triacetate and cellulose diacetate, and, for example, polymethyl methacrylate resin (PMMA resin). It is composed of (meth)acrylic resin.

The protective film in the present invention has the sign of the dimensional change rate (85°C) and the dimensional change rate (30°C) as long as the absolute value of the difference between the dimensional change rate (85°C) and the dimensional change rate (30°C) is within the range of the present invention. The signs of may all be the same sign (positive, negative, or zero), or different signs.

In this invention, as for a protective film, the absolute value of the difference of the dimensional change rate (85 degreeC) of a protective film, and the dimensional change rate (30 degreeC) of the said protective film is 0.02-0.50. Preferably, the absolute value of the difference of the dimensional change rate (85 degreeC) of a protective film and the dimensional change rate (30 degreeC) of the said protective film is 0.03-0.30, More preferably, it is 0.03-0.20.

Since the polarizing plate of the present invention has the absolute value of the difference in the dimensional change rate in such a range, cracks occurring in the polarizer under high-temperature conditions and high-humidity conditions can be suppressed and light leakage can be suppressed, so a polarizing plate with excellent durability is provided Moreover, also in the environment where high temperature and low temperature are repeated, the polarizing plate of this invention can show favorable polarization characteristic, without generating light leakage, a crack, etc.

Moreover, a polarizing plate having a protective film having such characteristics can make the polarizer thin, and can suppress cracking of the polarizer even when a scratch occurs on the surface of the protective film.

In a preferred embodiment, the polarizing plate according to the present invention comprises:

Let the dimensional change rate (85 °C) of the polarizer be the rate of dimensional change after 1 hour has elapsed under the condition of 85 °C relative humidity of 5% in the transmission axis direction of the polarizer,

Let the dimensional change rate of the polarizer (30 ° C) be the rate of dimensional change of the polarizer after 0.5 hours under the condition of 95% relative humidity at 30 ° C in the direction of the transmission axis of the polarizer,

Let the absolute value of the difference between the dimensional change rate (85 ° C.) of the polarizer and the dimensional change rate (30 ° C.) of the polarizer be F _PZ ,

Let F _PF be the absolute value of the difference between the dimensional change rate (85 ° C.) of the protective film and the dimensional change rate (30 ° C.) of the protective film,

When the difference obtained by subtracting the F _PF from the F _PZ is ΔF _TD ,

ΔF _TD =F _PZ -F _PF ,

The calculation method of the dimensional change rate can be calculated according to the above.

Preferably, the ratio ΔF _TD to F _PZ (ΔF _TD /F _PZ ) is in the range of 0.5 to 0.95. More preferably, ΔF _TD /F _PZ is 0.55 to 0.95, still more preferably 0.60 to 0.95.

When ΔF _TD /F _PZ exceeds 0.95, the shrinkage and/or expansion behavior of the protective film is smaller than the shrinkage/expansion behavior of the polyvinyl alcohol film, and due to deformation between the polyvinyl alcohol film and the protective film, the polyvinyl Alcohol film cracks may occur.

When a polarizer and a protective film have such a relationship, the crack which generate|occur|produces in a polarizer under high temperature conditions and high humidity conditions is suppressed, and the polarizing plate excellent in durability is provided. Moreover, also in the environment where high temperature and low temperature are repeated, the polarizing plate of this invention can show favorable polarization characteristic, without generating light leakage, a crack, etc. Moreover, the polarizing plate which has a protective film which has such a characteristic can make a polarizer thin, and can suppress the crack of a polarizer even when a wound generate|occur|produces on the surface of a protective film.

In a preferred embodiment, the polarizing plate of the present invention is a polarizing plate in which a polarizer, a protective film, and an adhesive layer are disposed in this order. In another preferred embodiment, the polarizing plate of the present invention is a polarizing plate in which a protective film, a polarizer, and an adhesive layer are disposed in this order. In a preferred embodiment, the polarizer and the protective film of the present invention are bonded through an adhesive layer. The thickness of the adhesive layer is, for example, 0.01 µm to 5 µm. As an adhesive bond layer, a well-known thing can be used in the said technical field.

For example, the polarizing plate of the present invention may have an absorption axis and a transmission axis of the polarizer, as shown in FIG. 2 .

For example, Fig. 2(a) shows the transmission axis 11a and the absorption axis ( It is a schematic plan view showing the axial angle of 11b). 2(b) shows the transmission axis 11a and the absorption axis 11b of the polarizing plate 100 having the transmission axis 11a of the polarizer in the long direction and the absorption axis 11b of the polarizer in the width direction. It is a schematic plan view showing the axis angle of .

In a preferred embodiment, as shown in FIG. 2A , the outer shape of the polarizing plate 100 may be, for example, a rectangular shape having a long side and a short side. In this case, the transmission axis 11a of the polarizing plate 100 (polarizer 11) and the short side of the polarizing plate 100 may be parallel or substantially parallel (the forming angle is within ±7 degrees). On the other hand, the absorption axis 11b is orthogonal to the transmission axis 11a.

Further, in another preferred embodiment, as shown in Fig. 2(b), the transmission axis 11a of the polarizing plate 100 (polarizer 11) and the long side of the polarizing plate 100 are parallel or substantially parallel ( The angle formed may be within ±7 degrees). On the other hand, the absorption axis 11b is orthogonal to the transmission axis 11a.

[Polarizer]

The polarizer may be one in which a dichroic dye is adsorbed and oriented in a uniaxially stretched polyvinyl alcohol-based resin layer. A polarizer can implement|achieve thin film formation of a polarizing plate as thickness is 20 micrometers or less normally. In the present invention, for example, a polarizer having a thickness of 10 µm or less, more preferably a polarizer having a thickness of 8 µm or less can be employed. Moreover, the polarizer in this invention has a thickness of 2 micrometers or more normally.

As polyvinyl alcohol-type resin, what saponified polyvinyl acetate-type resin can be used. As polyvinyl acetate-type resin, the copolymer of vinyl acetate and other monomer copolymerizable to this other than polyvinyl acetate which is a homopolymer of vinyl acetate is illustrated. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acid, olefin, vinyl ether, unsaturated sulfonic acid, and acrylamide having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin may be in the range of 80 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more. The polyvinyl alcohol-based resin may be a partially modified polyvinyl alcohol, and for example, the polyvinyl alcohol-based resin may be mixed with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; What modified|denatured with the alkylester of unsaturated carboxylic acid, acrylamide, etc. are mentioned. The average polymerization degree of polyvinyl alcohol-type resin becomes like this. Preferably it is 100-10000, More preferably, it is 1500-8000, More preferably, it is 2000-5000.

The polarizer is, for example, uniaxially stretching a raw film composed of a polyvinyl alcohol-based resin, dyeing with a dichroic dye (dyeing treatment), treating with an aqueous boric acid solution (boric acid treatment), washing with water ( washing treatment), and finally drying.

Uniaxial stretching of a polyvinyl alcohol-type resin film may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, and may be performed after dyeing with a dichroic dye. When performing uniaxial stretching after dyeing|staining with a dichroic dye, this uniaxial stretching may be performed before a boric-acid process, and may be performed during a boric-acid process. Moreover, of course, it is also possible to perform uniaxial stretching in these several steps. In order to perform uniaxial stretching, you may extend|stretch through between rolls from which circumferential speed differs, and you may extend|stretch by the method of pinching|interposing between hot rolls. Moreover, the dry type extending|stretching which extends|stretches in air|atmosphere may be sufficient, and wet extending|stretching which extends|stretches in the state swollen with the solvent may be sufficient. The final draw ratio of a polyvinyl alcohol-type resin film is about 4 to 8 times normally.

In a dyeing|staining process, a polyvinyl alcohol-type resin film is dye|stained with a dichroic dye, and a dichroic dye is made to adsorb|suck to a film. What is necessary is just to immerse a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye, for example for a dyeing process. As a dichroic dye, iodine or a dichroic dye is specifically used.

When using an iodine as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing normally iodine and potassium iodide is employ|adopted. Content of the iodine in this aqueous solution is about 0.01-0.5 weight part normally per 100 weight part of water, and content of potassium iodide is about 0.5-10 weight part normally per 100 weight part of water. The temperature of this aqueous solution is about 20-40 degreeC normally, and the immersion time to this aqueous solution is about 30 to 300 second normally.

On the other hand, when using a dichroic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing a water-soluble dichroic dye is usually employ|adopted. Content of the dichroic dye in this aqueous solution is about 1x10 ^-3 - 1x10 ^-2 weight part normally per 100 weight part of water. This aqueous solution may contain inorganic salts, such as sodium sulfate. The temperature of this aqueous solution is about 20-80 degreeC normally, Moreover, the immersion time to this aqueous solution is about 30-300 second normally.

The boric acid treatment is performed, for example, by immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. Content of boric acid in boric-acid aqueous solution is about 2-15 weight part normally per 100 weight part of water, Preferably it is 5-12 weight part. When using an iodine as a dichroic dye, it is preferable that this aqueous boric acid solution contains potassium iodide. Content of potassium iodide in boric-acid aqueous solution is about 2-20 weight part normally per 100 weight part of water, Preferably it is 5-15 weight part. The immersion time of the film in boric acid aqueous solution is usually about 100 to 1200 seconds, Preferably it is 150 second or more, More preferably, it is 200 second or more, More preferably, it is 600 second or less, More preferably, it is 400 second or less. . The temperature of boric acid aqueous solution is 50 degreeC or more normally, Preferably it is 50-85 degreeC. You may add sulfuric acid, hydrochloric acid, acetic acid, ascorbic acid, etc. to boric-acid aqueous solution as a pH adjuster.

A water washing process is normally performed to the polyvinyl alcohol-type resin film after a boric acid process. The water washing process is performed by immersing the polyvinyl alcohol-type resin film by which the boric acid process was carried out, for example in water. Drying is performed after water washing, and a polarizer is obtained. The temperature of the water in a water washing process is about 5-40 degreeC normally, and immersion time is about 2-120 second normally. Drying performed after that is normally performed using a hot-air dryer or a far-infrared heater. The drying temperature is normally 40-100 degreeC, and drying time is about 120-600 second normally.

[protective film]

As mentioned above, in the protective film in this invention, the absolute value of the difference of the dimensional change rate (85 degreeC) of a protective film, and the dimensional change rate (30 degreeC) of the said protective film is 0.02-0.50.

A protective film is laminated|stacked on at least single side|surface of a polarizer. In addition, you may laminate|stack a protective film (1st protective film) on the single side|surface of a polarizer, and you may laminate|stack another protective film (2nd protective film) on the other side. Preferably, a protective film (1st protective film) is laminated|stacked on the single side|surface of a polarizer. A single layer may be sufficient as a 1st protective film and a 2nd protective film, and what laminated|stacked a some film with an adhesive or an adhesive agent may be sufficient as it.

The protective film (first protective film) and the second protective film may be transparent resin films each made of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin-based resins such as chain polyolefin-based resins and cyclic polyolefin-based resins exemplified by polypropylene-based resins; cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; polyester-based resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate-based resin; (meth)acrylic resin selected from polymethyl methacrylate resin; or a mixture of at least two or more thereof. Moreover, you may use the copolymer of at least 2 or more types of monomers which comprise the said resin.

Cyclic polyolefin-based resin is a generic name for resins that are usually polymerized using a cyclic olefin as a polymerization unit, for example, in Japanese Patent Application Laid-Open No. 1-240517, Japanese Patent Application Laid-Open No. 3-14882, and Japanese Patent Application Laid-Open No. Heisei 3 -122137, etc. are mentioned resin described in it. When specific examples of the cyclic polyolefin resin are given, a ring-opened (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, a copolymer of a chain olefin such as ethylene and propylene and a cyclic olefin (typically a random copolymer) , and graft polymers modified with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers are preferably used as cyclic olefins.

As for cyclic polyolefin resin, various products are marketed. As examples of commercial products of cyclic polyolefin resins, all are trade names, "TOPAS" (registered trademark) sold by TOPAS ADVANCED POLYMERS GmbH and sold by Polyplastics Co., Ltd. in Japan, "Aton" sold by JSR Corporation "(registered trademark), "ZEONOA" (registered trademark) and "ZEONEX" (registered trademark) sold by Nippon Zeon Corporation, and "APPEL" (registered trademark) sold by Mitsui Chemicals Co., Ltd. etc.

Moreover, you may use the commercial item of the cyclic polyolefin resin film formed into a film as a protective film. Examples of commercially available products include "Aton Film" ("Aton" is a registered trademark of the company) sold by JSR Corporation, all under trade names, and "Sushina" (registered trademark) sold by Sekisui Chemical Co., Ltd. ) and "SCA40", "Zeonoa Film" sold by Nippon Zeon Corporation (registered trademark), and the like.

Cellulose ester-based resins are usually esters of cellulose and fatty acids. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, what copolymerized these and the thing by which a part of hydroxyl group was modified by other substituents can also be used. Among these, cellulose triacetate (triacetyl cellulose: TAC) is especially preferable. As for cellulose triacetate, many products are marketed and it is advantageous also at the point of availability and cost. Examples of commercial products of cellulose triacetate are "FUJITAC (registered trademark) TD80", "FUJITAC (registered trademark) TD80UF", "FUJITAC (registered trademark) trademarks) TD80UZ" and "Fujitak (registered trademark) TD40UZ", TAC films "KC8UX2M", "KC2UA" and "KC4UY" manufactured by Konica Minolta Co., Ltd., and the like.

Polymethacrylic acid ester and polyacrylic acid ester (Hereinafter, polymethacrylic acid ester and polyacrylic acid ester may be collectively called (meth)acrylic-type resin.), and can be obtained easily in the market.

As (meth)acrylic-type resin, the homopolymer of methacrylic acid alkylester or acrylic acid alkylester, the copolymer of methacrylic acid alkylester, and acrylic acid alkylester, etc. are mentioned, for example. Specifically as the methacrylic acid alkyl ester, methyl methacrylate, ethyl methacrylate, propyl methacrylate, etc., and specifically as the acrylic acid alkyl ester, methyl acrylate, ethyl acrylate, propyl acrylate, etc. can be heard What is marketed as a general-purpose (meth)acrylic-type resin can be used for such (meth)acrylic-type resin. As the (meth)acrylic resin, what is called an impact-resistant (meth)acrylic resin may be used.

(meth)acrylic resin is a polymer mainly having methacrylic acid ester normally. A homopolymer of one type of methacrylic acid ester may be sufficient as methacrylic resin, and the copolymer of a methacrylic acid ester and another methacrylic acid ester, an acrylic acid ester, etc. may be sufficient as it. As methacrylic acid ester, alkyl methacrylates, such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate, are mentioned, Carbon number of the alkyl group is about 1-4 normally. Further, cycloalkyl methacrylate, such as cyclopentyl methacrylate, cyclohexyl methacrylate, and methacrylic, aryl methacrylate such as phenyl methacrylate, cycloalkylalkyl methacrylate such as cyclohexylmethyl methacrylate; Aralkyl methacrylates, such as benzyl methacrylate, can also be used.

As said other polymerizable monomer which can comprise (meth)acrylic-type resin, polymerizable monomers other than acrylic acid ester, methacrylic acid ester, and acrylic acid ester are mentioned, for example. As the acrylic acid ester, an acrylic acid alkyl ester can be used, and specific examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, and 2-ethyl acrylate. and acrylic acid alkyl esters having 1 to 8 carbon atoms in the alkyl group such as hexyl, cyclohexyl acrylate, and 2-hydroxyethyl acrylate. Preferably carbon number of an alkyl group is 1-4. (meth)acrylic resin WHEREIN: Acrylic acid ester may be used individually by 1 type, and may use 2 or more types together.

Examples of the polymerizable monomer other than the methacrylic acid ester and the acrylic acid ester include a monofunctional monomer having one polymerizable carbon-carbon double bond in the molecule, and a polyfunctional monomer having at least two polymerizable carbon-carbon double bonds in the molecule. However, monofunctional monomers are preferably used. Specific examples of the monofunctional monomer include styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, halogenated styrene and hydroxystyrene; vinyl cyanide such as acrylonitrile and methacrylonitrile; unsaturated acids such as acrylic acid, methacrylic acid, maleic anhydride, and itaconic anhydride; maleimides such as N-methylmaleimide, N-cyclohexylmaleimide and N-phenylmaleimide; allyl alcohol such as methacryl alcohol and allyl alcohol; other monomers such as vinyl acetate, vinyl chloride, ethylene, propylene, 4-methyl-1-pentene, 2-hydroxymethyl-1-butene, methylvinyl ketone, N-vinylpyrrolidone, N-vinylcarbazole, etc. do.

Specific examples of the polyfunctional monomer include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, and trimethylolpropane triacrylate; alkenyl esters of unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, and allyl cinnamate; and aromatic polyalkenyl compounds such as polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate and triallyl isocyanurate, and divinylbenzene. Polymerizable monomers other than methacrylic acid ester and acrylic acid ester may be used individually by 1 type, and may use 2 or more types together.

A preferred monomer composition of the (meth)acrylic resin is 50-100 wt% of alkyl methacrylate, 0-50 wt% of acrylic acid alkylester, and 0-50 wt% of other polymerizable monomers based on the total amount of monomers. It is weight%, More preferably, 50 to 99.9 weight% of methacrylic acid alkylester, 0.1 to 50 weight% of acrylic acid alkylester, and 0 to 49.9 weight% of polymerizable monomers other than these.

Moreover, (meth)acrylic-type resin may have a ring structure in a polymer main chain at the point which can improve durability of a film. It is preferable that ring structures are heterocyclic structures, such as a cyclic acid anhydride structure, a cyclic imide structure, and a lactone ring structure. Specific examples include cyclic acid anhydride structures such as glutaric anhydride and succinic anhydride structures, cyclic imide structures such as glutarimide structures and succinimide structures, and lactone ring structures such as butyrolactone and valerolactone. can The glass transition temperature of (meth)acrylic-type resin can be made high, so that content of the ring structure in a principal chain is enlarged. The cyclic acid anhydride structure or the cyclic imide structure is introduced by copolymerizing a monomer having a cyclic structure such as maleic anhydride or maleimide; It can be introduced by, for example, a method in which an amino compound is reacted to introduce a cyclic imide structure. The resin (polymer) having a lactone ring structure is prepared by preparing a polymer having a hydroxyl group and an ester group in the polymer chain, and then heating the hydroxyl group and the ester group in the obtained polymer by heating, if necessary, such as an organophosphorus compound. It can obtain by the method of carrying out cyclization condensation in the presence of a catalyst and forming a lactone ring structure.

The polymer having a hydroxyl group and an ester group in the polymer chain is, for example, 2-(hydroxymethyl)methyl acrylate, 2-(hydroxymethyl)ethyl acrylate, 2-(hydroxymethyl) isopropyl acrylate, 2-(hydroxy It can be obtained by using (meth)acrylic acid ester having a hydroxyl group and an ester group, such as n-butyl methyl)acrylate and t-butyl 2-(hydroxymethyl)acrylate as a part of the monomer. A more specific preparation method of a polymer having a lactone ring structure is described in, for example, Japanese Patent Application Laid-Open No. 2007-254726.

(meth)acrylic resin can be prepared by radically polymerizing the monomer composition containing the above monomers. A monomer composition can contain a solvent and a polymerization initiator as needed.

(meth)acrylic-type resin may contain other resin other than the above-mentioned (meth)acrylic-type resin. The content rate of the said other resin becomes like this. Preferably it is 0 to 70 weight%, More preferably, it is 0 to 50 weight%, More preferably, it is 0 to 30 weight%. Examples of the resin include olefinic polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly(4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and vinyl chloride resin; styrenic polymers such as polystyrene, styrene-methyl methacrylate copolymer, and styrene-acrylonitrile copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyarylate comprising an aromatic diol and an aromatic dicarboxylic acid; biodegradable polyesters such as polylactic acid and polybutylene succinate; polycarbonate; polyamides such as nylon 6, nylon 66, and nylon 610; polyacetal; polyphenylene oxide; polyphenylene sulfide; polyether ether ketone; polyethernitrile; polysulfone; polyether sulfone; polyoxybenzylene; polyamideimide and the like.

(meth)acrylic resin may contain rubber particle|grains from a viewpoint of improving the impact resistance and film forming property of a film. The rubber particles may be particles composed of only a layer exhibiting rubber elasticity, or particles having a multilayer structure having another layer together with a layer exhibiting rubber elasticity. Examples of the rubber elastomer include an olefin elastomer, a diene elastomer, a styrene-diene elastomer, and an acrylic elastomer. Among them, an acrylic elastic polymer is preferably used from the viewpoint of light resistance and transparency.

The acrylic elastic polymer may be a polymer mainly composed of alkyl acrylate, ie, containing 50 wt% or more of structural units derived from alkyl acrylate based on the total amount of monomers. The acrylic elastic polymer may be a homopolymer of alkyl acrylate, or a copolymer containing 50% by weight or more of structural units derived from alkyl acrylate and 50% by weight or less of structural units derived from other polymerizable monomers.

As the alkyl acrylate constituting the acrylic elastomer, those having 4 to 8 carbon atoms in the alkyl group are usually used. When the example of the said other polymerizable monomer is given, For example, Alkyl methacrylate, such as methyl methacrylate and ethyl methacrylate; styrene-based monomers such as styrene and alkylstyrene; monofunctional monomers such as unsaturated nitriles such as acrylonitrile and methacrylonitrile, and furthermore, alkenyl esters of unsaturated carboxylic acids such as (meth) allyl acrylate and methacrylic (meth) acrylate; dialkenyl esters of dibasic acids such as diallyl maleate; It is a polyfunctional monomer, such as an unsaturated carboxylic acid diester of glycol, such as alkylene glycol di(meth)acrylate.

It is preferable that the rubber particle containing an acrylic elastic polymer is a particle|grains of the multilayer structure which has a layer of an acrylic elastic polymer. Specifically, it has a two-layer structure having a hard polymer layer mainly composed of alkyl methacrylate on the outside of the layer of the acrylic elastomer, and a hard polymer layer mainly composed of alkyl methacrylate inside the layer of the acrylic elastomer. The thing of a three-layer structure which has a polymer layer of

Examples of the monomer composition in the polymer mainly comprising alkyl methacrylate constituting the hard polymer layer formed outside or inside the layer of the acrylic elastomer are alkyl methacrylate given as an example of the (meth)acrylic resin. It is the same as the example of the monomer composition of the polymer which has as a main component, and especially the monomer composition which has methyl methacrylate as a main body is used preferably. The acrylic rubber elastic particles having such a multilayer structure can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

The rubber particles have an average particle diameter of 10 to 350 nm from the viewpoint of the film forming properties of the (meth)acrylic resin, the impact resistance of the film, and the slipperiness of the film surface to the rubber elastomer layer (layer of the acrylic elastomer) contained therein. It is preferable to be in the range of The said average particle diameter becomes like this. More preferably, it is 30 nm or more, Furthermore, it is 50 nm or more, More preferably, it is 300 nm or less, Furthermore, it is 280 nm or less.

The average particle diameter from the rubber particles to the elastic rubber layer (layer of the acrylic elastic polymer) is measured as follows. That is, when these rubber particles are mixed with a (meth)acrylic resin to form a film, and the cross section is dyed with an aqueous solution of ruthenium oxide, only the rubber elastic layer is colored and observed in a substantially circular shape, and the (meth)acrylic resin of the parent layer is not dyed Then, from the cross section of the film dyed in this way, a thin slice is prepared using a microtome etc., and this is observed with an electron microscope. Then, after randomly extracting 100 dyed rubber particles and calculating the respective particle diameters (diameters up to the rubber elastic body layer), the number average value is taken as the average particle diameter. Since it measures by this method, the said average particle diameter obtained is a number average particle diameter.

When the outermost layer is a hard polymer mainly composed of methyl methacrylate, and rubber particles in which an elastic rubber layer (a layer of an acrylic elastic polymer) is wrapped, it is mixed with the (meth)acrylic resin of the parent. The outermost layer of the particles is mixed with the (meth)acrylic resin of the parent. Therefore, when the cross section is dyed with ruthenium oxide and observed with an electron microscope, rubber particles are observed as particles in a state from which the outermost layer has been removed. Specifically, when the inner layer is an acrylic elastomer and the outer layer is rubber particles having a two-layer structure in which the outer layer is a hard polymer mainly composed of methyl methacrylate, the acrylic elastomer portion of the inner layer is dyed and observed as particles having a single layer structure. do. In the case of rubber particles having a three-layer structure, in which the innermost layer is a hard polymer mainly composed of methyl methacrylate, the middle layer is an acrylic elastomer, and the outermost layer is a hard polymer mainly composed of methyl methacrylate, The particle center portion of the innermost layer is not dyed, and only the acrylic elastomer portion of the intermediate layer is observed as the dyed two-layer structure particles.

From the viewpoint of the film forming property of the (meth)acrylic resin, the impact resistance of the film, and the slipperiness of the film surface, the rubber particles are 3 wt% based on the total amount with the (meth)acrylic resin constituting the (meth)acrylic resin film As mentioned above, it is preferable to mix|blend in the ratio of 60 weight% or less, More preferably, it is 45 weight% or less, More preferably, it is 35 weight% or less. When the rubber elastomer particles are more than 60% by weight, the dimensional change of the film is large, and the heat resistance is lowered. On the other hand, when the rubber elastic body particle|grains are less than 3 weight%, although the heat resistance of a film is favorable, the winding property at the time of film forming is bad, and productivity may fall. On the other hand, in the present invention, when particles of a multilayer structure having a layer exhibiting rubber elasticity and another layer are used as rubber elastic particles, the weight of a portion consisting of a layer exhibiting rubber elasticity and an inner layer is calculated as the rubber Let it be the weight of elastic body particle|grains. For example, when the acrylic rubber elastomer particles having the three-layer structure described above are used, the total weight of the acrylic rubber elastomer portion of the intermediate layer and the hard polymer portion mainly composed of methyl methacrylate in the innermost layer is the weight of the rubber elastomer particles do it with When the acrylic rubber elastomer particles having the three-layer structure described above are dissolved in acetone, the acrylic rubber elastomer portion of the intermediate layer and the hard polymer portion mainly composed of methyl methacrylate in the innermost layer remain as insoluble content, so the three-layer structure The weight ratio of the sum total of the intermediate|middle layer and innermost layer which occupies for the acrylic rubber elastic body particle|grains of can be calculated|required easily.

In the case where the (meth)acrylic resin film contains rubber particles, the (meth)acrylic resin composition containing the rubber particles used in the production of the film is mixed with the (meth)acrylic resin and rubber particles by melt kneading or the like. It can be obtained also by the method of preparing rubber particles first, and polymerizing the monomer composition used as a raw material of (meth)acrylic-type resin in the presence besides what can be obtained by carrying out.

The protective film may contain ordinary additives such as ultraviolet absorbers, organic dyes, pigments, inorganic dyes, antioxidants, antistatic agents, surfactants, and the like. Among them, the ultraviolet absorber is preferably used for improving weather resistance. Examples of the ultraviolet absorber include 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(5- Methyl-2-hydroxyphenyl)-2H-benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3, 5-di-tert-butyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)-5-chloro-2H-benzotriazole , 2- (3,5-di-tert-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole-based ultraviolet absorbers such as -2H-benzotriazole and 2-(2'-hydroxy-5'-tert-octylphenyl)-2H-benzotriazole; 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4'-chlorobenzophenone , 2-hydroxybenzophenone-based ultraviolet absorbers such as 2,2'-dihydroxy-4-methoxybenzophenone and 2,2'-dihydroxy-4, 4'-dimethoxybenzophenone; salicylic acid phenyl ester ultraviolet absorbers such as p-tert-butylphenyl salicylic acid ester and p-octylphenyl salicylic acid ester; 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxy Phenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2 -Hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine , 2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyl) Oxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4-di Phenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4 ,6-bis(4-phenylphenyl)-1,3,5-triazine, 4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1, 3,5-triazine, 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyloxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethyl Phenyl)-1,3,5-triazine, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-hydroxyphenyl, 2 -[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, 2-[2,6-di(2,4) -Xylyl)-1,3,5-triazin-2-yl]-5-octyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5 -[2-(2-ethylhexanoyl)ethoxy]phenol, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methoxyphenyl)-1,3,5-triazine and triazine-based ultraviolet absorbers such as these, and two or more of these may be used as needed.

As the ultraviolet absorber, a commercially available product may be used, for example, as a triazine-based ultraviolet absorber, "Kemisorb 102" (registered trademark) manufactured by Chemipro Chemical Co., Ltd. (registered trademark), and "ADEKA STAB (registered trademark) LA46" manufactured by ADEKA Corporation , "Adekastave (registered trademark) LAF70", "TINUVIN (registered trademark) 460", "TINUVIN (registered trademark) 405", "TINUVIN (registered trademark) 400" and "TINUVIN (registered trademark) 477" manufactured by BASF ", "CYASORB (registered trademark) UV-1164" manufactured by Sun Chemicals Co., Ltd. (above, both are brand names). As a benzotriazole type ultraviolet absorber, "ADEKA STAB LA31" and "ADEKA STAB LA36" manufactured by ADEKA, "SmiSorb (registered trademark) 200", "SmiSorb" manufactured by Sumika Chemtex Co., Ltd. (registered trademark) 250”, “Smisorb (registered trademark) 300”, “Smisorb (registered trademark) 340” and “Smisorb (registered trademark) 350”, “Kemisorb” manufactured by Kemipro Kasei Co., Ltd. 74" (registered trademark), "Kemisorb 79" (registered trademark) and "Kemisorb 279" (registered trademark), "TINUVIN (registered trademark) 99-2", "TINUVIN (registered trademark) 900" and " TINUVIN (registered trademark) 928" (above, all are brand names) etc. are mentioned. When the (meth)acrylic resin film contains the ultraviolet absorber, the amount is usually 0.1% by weight or more, preferably 0.3% by weight or more, and preferably 3% by weight based on 100% by weight of the (meth)acrylic resin. is below.

A conventionally well-known film forming method is employable for preparation of a (meth)acrylic-type resin film. The (meth)acrylic resin film may have a multilayer structure, and for the (meth)acrylic resin film of the multilayer structure, various commonly known methods such as a method using a feed block and a method using a multi-manifold die can be used. . Among them, for example, a method of laminating through a feed block, performing multilayer melt extrusion molding from a T-die, and contacting at least one side of a laminated film-like material obtained by contacting a roll or a belt to form a film from the viewpoint of obtaining a film with good surface properties desirable. In particular, from the viewpoint of improving the surface smoothness and surface glossiness of the (meth)acrylic resin film, a method in which both surfaces of the laminated film obtained by the multilayer melt extrusion molding are brought into contact with the roll surface or the belt surface to form a film is preferable. In the roll or belt used at this time, the surface of the roll or belt in contact with the (meth)acrylic resin is preferably a mirror surface for imparting smoothness to the surface of the (meth)acrylic resin film.

The (meth)acrylic-type resin film may extend|treat the extending|stretching process with respect to the film produced as mentioned above. In order to obtain a film which has desired optical properties or mechanical properties, stretching treatment may be required. Examples of the stretching treatment include uniaxial stretching and biaxial stretching. As an extending|stretching direction, the machine flow direction (MD) of an unstretched film, the direction (TD) orthogonal to this, the direction intersecting to the machine flow direction (MD), etc. are mentioned. The biaxial stretching may be simultaneous biaxial stretching in which two stretching directions are simultaneously stretched, or sequential biaxial stretching in which the stretching in the other directions is performed after stretching in a predetermined direction.

The protective film which has optical functions, such as retardation film and a brightness improvement film, may be sufficient as a 1st protective film and a 2nd protective film as long as it is included in the scope of the present invention. For example, by stretching (uniaxial stretching or biaxial stretching, etc.) a transparent resin film made of the above material, or forming a liquid crystal layer or the like on the film, a retardation film to which an arbitrary retardation value is imparted can be obtained.

The 1st protective film and the 2nd protective film can also form surface treatment layers (coating layer), such as a hard-coat layer, a glare-proof layer, an antireflection layer, an antistatic layer, and a stain|pollution|contamination prevention layer, on the surface on the opposite side to a polarizer. A well-known method can be used for the method of forming a surface treatment layer on the protective film surface.

The same protective film may be sufficient as a 1st protective film and a 2nd protective film, and different protective films may be sufficient as them. Examples of the case where the protective films are different include combinations in which the types of thermoplastic resins constituting the protective film are at least different; a combination at least different in the presence or absence or type of the optical function of the protective film; There are at least different combinations in the presence or absence or the type of the surface treatment layer formed on the surface.

Although it is preferable that the thickness of a 1st protective film and a 2nd protective film is thin from a viewpoint of thin film formation of a polarizing plate, when too thin, intensity|strength will fall and workability will be inferior. Therefore, as for the thickness of a 1st protective film and a 2nd protective film, 5-90 micrometers or less are preferable, More preferably, it is 60 micrometers or less, More preferably, it is 50 micrometers or less, Especially preferably, it is 30 micrometers or less.

If the protective film (1st protective film) has a moderate dimensional change by water absorption, the effect of this application will be easy to be acquired. Preferably, it is a transparent resin film composed of a cellulose ester-based resin, a polyester-based resin, a polycarbonate-based resin, a (meth)acrylic resin, or a mixture of at least two or more thereof, more preferably, a cellulose ester-based resin, A transparent resin film composed of a (meth)acrylic resin or a mixture of at least two or more thereof.

(adhesive)

As the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer, a conventionally known pressure-sensitive adhesive may be appropriately selected, and in a high-temperature environment to which a polarizing plate is exposed, a moist heat environment, or an environment where high temperature and low temperature are repeated, peeling or the like does not occur. What is necessary is just to have adhesiveness. Specifically, an acrylic adhesive, a silicone adhesive, a rubber adhesive etc. are mentioned, The point of transparency, weather resistance, heat resistance, and workability to an acrylic adhesive is especially preferable.

In the pressure-sensitive adhesive, if necessary, a tackifier, a plasticizer, a glass fiber, glass beads, a metal powder, a filler composed of other inorganic powder, a pigment, a colorant, a filler, an antioxidant, an ultraviolet absorber, an antistatic agent, a silane coupling agent, etc. , various additives may be appropriately blended.

An adhesive layer is normally formed by apply|coating an adhesive on a release sheet, and drying the solution of an adhesive. For application on the release sheet, for example, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, a spraying method, or the like can be employed. The release sheet in which the adhesive layer was formed is used by the method etc. which transcribe|transfer this. The thickness of an adhesive layer is about 3-100 micrometers normally, Preferably it is 5-50 micrometers.

Preferably, it is preferable that the storage elastic modulus in 23 degreeC of an adhesive layer is 0.01 Mpa - 1 Mpa. When the storage elastic modulus of an adhesive layer is less than 0.01 Mpa, the shrinkage|contraction of the polarizing plate at the time of a high temperature test cannot be suppressed, but there exists a tendency for appearance defects, such as peeling, to become easy to generate|occur|produce. In addition, when the storage elastic modulus of the pressure-sensitive adhesive layer is greater than 1 MPa, the pressure-sensitive adhesive cannot relieve the deformation that occurs between the glass and the polarizing plate during the cold-heat shock test, and cracks tend to occur in the polarizing plate.

Preferred embodiment WHEREIN: The storage elastic modulus in 80 degreeC of an adhesive layer is 0.01 Mpa - 1 Mpa.

A liquid crystal panel can be obtained by bonding a polarizing plate to a liquid crystal cell through an adhesive layer. Moreover, an organic electroluminescent display device can be obtained by bonding a polarizing plate to an organic electroluminescent display through an adhesive layer. For example, a liquid crystal panel and an organic electroluminescent display, as shown in FIG. 3 , a glass substrate 40 , a first pressure-sensitive adhesive layer 13 , a first protective film 12 , a polarizer 11 , and a second The pressure-sensitive adhesive layer 23 and the second protective film 22 may be configured.

ADVANTAGE OF THE INVENTION According to the polarizing plate of this invention, the polarizing plate which is thin and excellent in intensity|strength is provided.

Example

Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples, % and parts indicating the content or usage are based on weight unless otherwise noted.

[Manufacturing of polarizer]

A polyvinyl alcohol film (average degree of polymerization of about 2,400, degree of saponification of 99.9 mol% or more) having a thickness of 20 µm was uniaxially stretched to about 5 times by dry stretching, and while maintaining the tension state, pure water at 60°C After 1 minute immersion in the iodine / potassium iodide / water weight ratio of 0.05/5/100 in an aqueous solution was immersed at 28 ℃ 60 seconds. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100 at 72° C. for 300 seconds. Then, after washing|cleaning for 20 second with 26 degreeC pure water, it dried at 65 degreeC, and obtained the 7-micrometer-thick polarizer by which the iodine adsorption|suction orientation is carried out to the polyvinyl alcohol film.

[First Adhesive]

A commercially available pressure-sensitive adhesive sheet in which an acrylic pressure-sensitive adhesive layer having a thickness of 20 µm was laminated on the release-treated surface of a 38 µm-thick polyethylene terephthalate film (release film) subjected to the release treatment was used. The urethane acrylate oligomer is not mix|blended with the acrylic adhesive. The storage elastic modulus of the adhesive layer which removed the peeling film from the adhesive sheet was 0.05 Mpa at 23 degreeC, and 0.04 Mpa at 80 degreeC.

[Second pressure-sensitive adhesive layer]

An organic solvent solution obtained by adding a urethane acrylate oligomer and an isocyanate-based crosslinking agent to a copolymer of butyl acrylate and acrylic acid was placed on the release-treated surface of a 38 µm-thick polyethylene terephthalate film (release film) subjected to release treatment, and then in a die coater. It coated and dried so that the thickness after drying might be set to 5 micrometers by this, and the adhesive sheet on which the adhesive layer was laminated|stacked was obtained. The storage elastic modulus of the adhesive layer from which the peeling film was removed from the adhesive sheet was 0.40 Mpa at 23 degreeC, and 0.18 Mpa at 80 degreeC.

[First Protective Film-1]

A triacetyl cellulose film manufactured by Konica Minolta Corporation (thickness of 20 µm, in-plane retardation value at a wavelength of 590 nm = 1.2 nm, and thickness direction retardation value at a wavelength of 590 nm = 1.3 nm) was used.

[First Protective Film-2]

An unstretched TAC film having a product name of "KC2UA" manufactured by Konica Minolta Co., Ltd. and a thickness of 25 µm was used.

[First Protective Film-3]

A cycloolefin resin film (manufactured by Nippon Zeon Corporation) having a thickness of 13 µm was used. In-plane retardation at a wavelength of 590 nm (Re(590)) = 0.8 nm, retardation in the thickness direction at a wavelength of 590 nm (Rth(590)) = 3.4 nm, retardation in the thickness direction at a wavelength of 483 nm (Rth(483)) = The thickness direction retardation (Rth(755)) = 2.8 nm at 3.5 nm and a wavelength of 755 nm.

[First Protective Film-4]

A cyclic polyolefin-based resin film having a thickness of 23 µm and a trade name "Zeonoa Film (registered trademark) ZF14-023" manufactured by Nippon Zeon Corporation was used.

[First Protective Film-5]

A triacetyl cellulose film (manufactured by Toppan TOMOEGAWA Optical Film Co., Ltd., 25KCHC-TC with a thickness of 32 µm) having a surface treated with a hard coat (thickness of 7 µm) was used.

[First Protective Film-6]

The first protective film-1 was dissolved in 1,3-dioxolane to prepare 12 wt%, and after drying on a glass substrate with a bar coater (count: 60), it was coated to a thickness of 10 µm. After drying in 60 degreeC oven for 3 minutes, the coating film was peeled from glass, and 1st protective film-6 was obtained.

[Second Protective Film]

A brightness enhancement film (manufactured by 3M, trade name: Advanced Polarized Film, Version 3) having a thickness of 26 μm was used.

[Preparation of water-based adhesive]

With respect to 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (KL-318 manufactured by Kuraray Co., Ltd.) is dissolved, and in the aqueous solution, a polyamide epoxy compound which is a water-soluble epoxy compound (Sumika Chemtex Co., Ltd.) Sumirez Resin (registered trademark) 650 (30), an aqueous solution having a solid content concentration of 30%] was added to 1.5 parts to obtain a water-based adhesive.

[Production of polarizing plate precursor A]

A first protective film-1 was laminated on one side of the polarizer through a water-based adhesive. After lamination, the first protective film-1 and the polarizer were bonded by drying at 80°C for 5 minutes. The 2nd adhesive layer laminated|stacked on the peeling film was bonded by the surface on the opposite side to the bonding surface with 1st protective film-1 in a polarizer. The 1st adhesive layer laminated|stacked on the peeling film was bonded by the surface on the opposite side to the bonding surface with the polarizer in 1st protective film-1.

On the other hand, it bonded so that the transmission axis direction of a polarizer and the width direction of a protective film might become parallel.

In this way, the polarizing plate precursor A-1 in which the 1st adhesive layer, a protective film, a polarizer, and the 2nd adhesive layer were laminated|stacked in this order was produced.

Similarly, the polarizing plate precursor created using the 1st protective film -2 instead of the 1st protective film -1 was made into the polarizing plate precursor A-2. About other protective films, it carried out similarly, and created the polarizing plate precursor.

[Production of Polarizer A]

The peeling film on the 2nd adhesive layer in the said polarizing plate precursor was peeled. The second pressure-sensitive adhesive layer in the polarizing plate precursor A and the brightness improving film are bonded, and the first pressure-sensitive adhesive layer, the protective film (first protective film), the polarizer, the second pressure-sensitive adhesive layer, and the brightness enhancement film (the second protective film) are this The polarizing plate A laminated|stacked in order was obtained. For example, the polarizing plate created using the 1st protective film-1 was made into polarizing plate A1. Similarly, the polarizing plate which has such a structure created using 1st protective film-2 was made into polarizing plate A2.

[Production of Polarizer B]

Except having changed the lamination|stacking position of the polarizer in the said polarizing plate precursor A-1, and a protective film, it carried out similarly to the said polarizing plate A1, and produced the polarizing plate B1. Obtained polarizing plate B1 is a polarizing plate on which the 1st adhesive layer, a polarizer, a protective film (1st protective film), a 2nd adhesive layer, and the brightness improvement film (2nd protective film) were laminated|stacked in this order.

[Production of Polarizer C]

A first protective film-1 was laminated on one side of the polarizer through a water-based adhesive. After lamination, the 1st protective film and the polarizer were bonded together by drying at 80 degreeC for 5 minutes. The 1st adhesive layer laminated|stacked on the peeling film was bonded to the surface on the opposite side to the bonding surface with the 1st protective film in a polarizer, the peeling film was peeled after that, and the polarizing plate C was obtained. The obtained polarizing plate is a polarizing plate on which the 1st adhesive layer, a polarizer, and the protective film (1st protective film) were laminated|stacked in this order. On the other hand, also about the polarizing plate C, the polarizing plate using the 1st protective film-1 was made into the polarizing plate C1, for example, the polarizing plate using the 1st protective film-5 was made into the polarizing plate C5.

[Calculation of dimensional change rate]

About the said protective film, the dimensional change rate difference was measured by the following method.

On the other hand, in the protective film used by the Example and the comparative example, the width direction is a direction parallel to the transmission axis direction of a polarizer.

First, each elongate protective film was cut out into the square of 100 mm of elongate directions x 100 mm of width directions. After cutting of the protective film, the dimension (L0) of the width direction was measured using the two-dimensional measuring instrument "NEXIV VMR-12072" (made by Nikon Corporation). Similarly, the dimension in the long direction was also measured.

Then, the protective film was left still in an environment of 85 degreeC for 1 hour (humidity: 5%). After this process, the dimension (L85) of the width direction of a protective film and the dimension of a long picture were carried out similarly to the above, and were measured.

The dimensional change rate (%) was calculated|required from the following formula|equation, and the dimensional change rate (85 degreeC) of the width direction of a protective film, and the dimensional change rate of the elongate direction were computed.

Dimensional change rate (85℃)=[(L0-L85)/L0]×100

In addition, after calculating the dimensional change rate in an 85 degreeC environment, the same sample was left to stand for 15 minutes at a temperature of 23 degreeC, and 55% of humidity, Then, it left still under the conditions of 30 degreeC and 95% of relative humidity for 0.5 hour. After this process, the dimension (L30) of the width direction of a protective film and the dimension of the long direction were carried out similarly to the above, and it measured. The dimensional change rate (%) was calculated|required from the following formula|equation, and the dimensional change rate of the width direction of a protective film and the dimensional change rate of the elongate direction were computed. On the other hand, "L030" is after measuring the dimensional change rate (85 ° C.) in a direction parallel to the transmission axis direction (long direction or width direction) of the polarizer, and left at a temperature of 23 ° C. and a humidity of 55% for 15 minutes. It means the film dimension after.

Dimensional change rate (30℃)=[(L030-L30)/L0]×100

The absolute value of the difference between the calculated|required dimensional change rate (85 degreeC) and dimensional change rate (30 degreeC) was computed. These results are shown in Table 1. In addition, in a table|surface, "F _TD " is an abbreviation which shows the absolute value of the difference between a dimensional change rate (85 degreeC) and a dimensional change rate (30 degreeC). On the other hand, F _PZ of a polarizer was also measured by the method similar to the above.

Further, ΔF _TD (the difference between the absolute value F _PZ of the difference in the dimensional change rate of the polarizer and the absolute value F _PF of the difference in the dimensional change rate of the protective film) was calculated. In addition, the ratio of ΔF _TD to F _PZ (ΔF _TD /F _PZ ) was calculated. A result is shown in Table 1.

[Table 1]

[Cold and heat shock environment test and condensation cold and heat shock environment test]

The polarizing plate with an adhesive layer created as mentioned above was cut out to 100 mm x 60 mm, the peeling film was peeled from the 1st adhesive layer side, and it bonded to the glass plate through the exposed adhesive layer. The obtained sample for evaluation was subjected to a cold and thermal shock environmental test and a condensation cold shock environmental test to be described later.

[Cold heat shock environment test]

The cold and thermal shock environmental test was carried out under high temperature conditions (85° C.) using a cold and thermal shock test apparatus (product name "TSA-71L-A-3" sold by SPEC Co., Ltd.) in a state in which a polarizing plate was bonded to a glass plate. A holding time of 30 minutes and a low temperature condition (-40°C) holding time of 30 minutes were set as one cycle. On the other hand, the temperature transition time was made into 1 minute, and the conditions which do not introduce|transduce external air and do not generate|occur|produce dew condensation in the optical member were set in the temperature transition time 0 minute at the time of a temperature transition. This cycle was repeated 400 cycles to conduct the test.

[Condensation Cold Heat Shock Environment Test]

The dew condensation cold/heat shock environment test was performed under the conditions in which dew condensation was intentionally generated in the optical member by introducing external air into the apparatus for 5 minutes at the time of temperature transition in the above-mentioned cold/heat shock environment test. This cycle was repeated 400 cycles to conduct the test.

In this test, the temperature of the outside air was 23°C, and the relative humidity was 55%.

[Judgment]

After performing a cold and thermal shock environmental test (number of cycles: 400) and a dew condensation cold and thermal shock environmental test (number of cycles: 400), the presence or absence of cracks was visually confirmed. There was no change from before the test, and the thing in which light leakage did not generate|occur|produce under cross nicol after the test was made into "(circle)", and the thing which light leak generate|occur|produced under cross nicol after the test was made into "x".

In addition, about the sample which performed the dew condensation cold-heat shock environment test, the maximum length of the crack which generate|occur|produced in the sample was measured under cross nicol. Table 2 shows the results obtained in the cold and thermal shock environmental test and the dew condensation cold and thermal shock environmental test.

[Table 2]

It turns out that the polarizing plate of this invention has the outstanding effect also in any of a cold-heat shock environmental test and a dew condensation cold-and-heat shock environmental test from this result. That is, according to this invention, under high temperature conditions and high humidity conditions, light leakage does not generate|occur|produce in a polarizer, but the polarizing plate excellent in durability is provided. Moreover, also in the environment where high temperature and low temperature are repeated, the polarizing plate of this invention can show favorable polarization characteristic, without generating light leakage, a crack, etc.

Moreover, in the polarizing plate of this invention, the maximum length of the crack which generate|occur|produced by the dew condensation cold-heat shock environmental test is remarkably short compared with the polarizing plate of a comparative example. Therefore, the polarizing plate of this invention can suppress crack growth of a polarizer even if it is a high humidity condition in which dew condensation generate|occur|produces, and can maintain favorable polarization characteristic.

[Cold heat shock environment test after stabbing]

A crushed wound was formed on the surface of a polarizing plate, the cold-heat shock environmental test was done to this polarizing plate, and the presence or absence of the crack of a polarizer was confirmed. Specifically, it evaluated through the following processes.

The polarizing plate created as mentioned above was cut out to 100 mm x 60 mm. The peeling film on the 1st adhesive layer was peeled, and the polarizing plate was bonded to alkali-free glass (made by Corning, EAGLE XG (trademark)) through the 1st adhesive layer. A load of 3 N was applied to the surface of the polarizing plate by a scratch-type hardness tester (manufactured by Eriksen, Germany, Model 318, ball diameter 0.75 mm) at a position 1.0 mm from the end of the polarizing plate bonded to this glass, and a crushed wound was made. The depth of the pressed wound was 1 μm or less, and the size was 0.2 mm in diameter.

Moreover, 5 N, another polarizing plate WHEREIN: The sample which applied the load of 10 N to the surface by the scratch-type hardness tester at the place 1.0 mm from the edge part of the other polarizing plate bonded to glass was created.

Wounds caused by the operation of applying a load to the surface of the polarizing plate are usually when the protective film laminated on the polarizing plate is peeled off with a sharp instrument such as tweezers, when the backlight and the polarizing plate are bonded, Injuries occurring on the back are assumed.

By applying a load of 3 N, 5 N, or 10 N to a polarizing plate in which a pressed wound was formed on the surface, a cold/heat shock environment test (250 cycles) at a temperature of 85 ° C. and -40 ° C. (1 cycle for 30 minutes each) was carried out. Judgment was carried out as follows. A result is shown in Table 3.

[Judgment]

Even when any load was applied, the case where the light leakage of a polarizer did not generate|occur|produce under cross nicol was made into "(circle)" after a cold-thermal shock environmental test. When any one load was applied, the polarizer cracked after a cold-heat shock environment test, and the case where light leakage was confirmed under cross nicol or visually was made into "x".

[Table 3]

ADVANTAGE OF THE INVENTION According to this invention, light leakage is hard to generate|occur|produce under high temperature conditions and high humidity conditions, and the polarizing plate excellent in durability is provided. Moreover, also in the environment where high temperature and low temperature are repeated, the polarizing plate of this invention can show favorable polarization characteristic, without generating light leakage, a crack, etc. Moreover, according to this invention, even when a polarizer can be made thin and a flaw generate|occur|produces on the surface of a protective film, the crack of a polarizer can be suppressed.

This application claims priority on the basis of Japanese Patent Application No. 2015-223443, filed on November 13, 2015, and Japanese Patent Application No. 2016-079655, filed on April 12, 2016, All are incorporated herein by reference.

11: Polarizer
12: protective film (first protective film)
13: adhesive layer (first adhesive layer)
22: second protective film
23: second pressure-sensitive adhesive layer
40: glass substrate
100: polarizer

Claims (7)

A polarizing plate having a polarizer, a protective film, and an adhesive layer, the polarizing plate comprising:
The polarizer, the protective film, and the pressure-sensitive adhesive layer are arranged in this order,
The polarizer and the protective film are laminated only through an adhesive layer,
A second protective film is laminated through a second pressure-sensitive adhesive layer on the opposite side to the protective film of the polarizer, and
The second protective film is laminated on the polarizer only through the second pressure-sensitive adhesive layer,
The rate of dimensional change of the protective film in a direction parallel to the direction of the transmission axis of the polarizer after 1 hour has elapsed under the condition of 85 ° C. and 5% of relative humidity is defined as the rate of dimensional change of the protective film (85 ° C.);
When the rate of dimensional change of the protective film in a direction parallel to the direction of the transmission axis of the polarizer after 0.5 hours has elapsed under the conditions of 95% relative humidity at 30°C, the rate of dimensional change (30°C) of the protective film,
A polarizing plate having an absolute value of 0.02 to 0.50 of a difference between a dimensional change rate (85° C.) of the protective film and a dimensional change rate (30° C.) of the protective film. The dimensional change rate (85°C) of the polarizer according to claim 1, wherein the rate of dimensional change in the transmission axis direction of the polarizer after 1 hour has elapsed under the condition of 85°C and 5% relative humidity,
Let the rate of dimensional change of the polarizer in the transmission axis direction of the polarizer after 0.5 hours under the condition of 95% relative humidity at 30 °C be the rate of dimensional change of the polarizer (30 °C);
Let the absolute value of the difference between the dimensional change rate (85°C) of the polarizer and the dimensional change rate (30°C) of the polarizer be F _PZ ,
Let the absolute value of the difference between the dimensional change rate (85°C) of the protective film and the dimensional change rate (30°C) of the protective film be F _PF ,
A difference obtained by subtracting the F _PF from the F _PZ is ΔF _TD , and
A polarizing plate in which the ratio of ΔF _TD to F _PZ (ΔF _TD /F _PZ ) is in the range of 0.5 to 0.95. The polarizing plate according to claim 1, wherein the second protective film is a brightness enhancing film. The polarizing plate according to claim 1, wherein the polarizer has a thickness of 10 μm or less. According to claim 1, wherein the protective film and the second protective film is a cellulose ester-based resin; polyester-based resin; polycarbonate-based resin; (meth)acrylic resin; Or a polarizing plate that is a transparent resin film composed of a mixture of at least two or more thereof. The liquid crystal display device in which the polarizing plate in any one of Claims 1-5 was laminated|stacked on the liquid crystal cell via the said adhesive layer. The organic electroluminescent display device in which the polarizing plate in any one of Claims 1-5 was laminated|stacked on the organic electroluminescent display through the said adhesive layer.

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