KR102531339B1 - Polarizing plate laminate and image display apparatus comprising same - Google Patents

Abstract

The present invention is a polarizing plate; And a hard coating layer provided on an uppermost surface of the polarizing plate, wherein the maximum value of the loss tangent coefficient tanδ of the hard coating layer is 0.5 or less, and relates to a polarizing plate laminate and an image display device including the same.

Description

A polarizing plate laminate and an image display device including the same {POLARIZING PLATE LAMINATE AND IMAGE DISPLAY APPARATUS COMPRISING SAME}

The present specification relates to a polarizing plate laminate and an image display device including the same.

The image display device may include a display panel and polarizers provided on both sides of the display panel. The polarizing plate is adhered to the display panel via the adhesive layer, and a protective substrate is provided on the adhesive layer side and the opposite side of the polarizing plate.

Since the protective substrate provided on the opposite side of the surface of the polarizing plate on which the adhesive layer is provided must function to protect the polarizing plate from harsh external conditions, high rigidity and low moisture permeability are required.

Korean Patent Publication No. 2016-0142546

The present invention relates to a polarizing plate laminate and an image display device including the same.

The present invention is a polarizing plate; and a hard coating layer provided on an uppermost surface of the polarizing plate, wherein a maximum value of a loss tangent coefficient tanδ of the hard coating layer is 0.5 or less.

In addition, the present invention is an image display panel; And it provides an image display device comprising the above-described polarizing plate laminate provided on one side or both sides of the image display panel.

As the image display device of the present invention includes the hard coating layer provided on the top surface, it is possible to improve durability at high temperatures by protecting the image display device from external factors.

In addition, the image display device of the present invention can provide a thin image display device by including a hard coating layer having excellent durability without requiring a separate protective film.

In addition, as the image display device of the present invention includes a hard coating layer having improved rigidity and low moisture permeability, it is possible to protect the image display device from external factors and improve durability at high temperatures or high humidity.

1 and 2 show the polarizing plate laminate structure of the present invention.
3 shows the structure of an image display device including the polarizing plate laminate of the present invention.
4 and 5 show the results of Experimental Example 2.

Hereinafter, this specification will be described in more detail.

In the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

In this specification, when a member is said to be located “on” another member, this includes not only the case where a member is in contact with another member, but also the case where another member exists between the two members.

In the present specification, “polarizing plate” means a laminate including “polarizer”, and the polarizing plate may include other components than the polarizer. However, when the polarizing plate does not include other components other than the polarizer, the polarizing plate and the polarizer may be interpreted the same.

*16 In this specification, "upper surface" and "lower surface" are for specifying the location, and "upper surface" and "lower surface" of any member may include any member therebetween. In addition, "top surface" is intended to describe the outermost member among the members provided on the "upper surface", and "B provided on the top surface of A" means that the opposite side of the surface of B facing A means not included.

Conventionally, the polarizing plate was protected from harsh external environments by laminating a protective film on the uppermost surface of the polarizing plate included in the display panel. However, since the thickness of the protective film is thick, it is difficult to thin the image display device, and the adhesive used when laminating the protective film has reduced adhesive strength in a high temperature and high humidity environment, resulting in peeling of the protective film.

In the present invention, by providing a hard coating layer on the top surface of the polarizing plate instead of the conventional protective film, peeling of the hard coating layer was prevented even if a separate adhesive layer was not provided. In addition, high-temperature durability could be improved by adjusting the maximum value of the loss tangent coefficient tanδ of the hard coating layer to be 0.5 or less.

Specifically, the present invention is a polarizing plate; and a hard coating layer provided on an uppermost surface of the polarizing plate, wherein a maximum value of a loss tangent coefficient tanδ of the hard coating layer is 0.5 or less.

The polarizing plate laminate may be attached to an image display panel to configure an image display device.

Referring to FIG. 1, the structure of the polarizing plate laminate of the present invention will be described. 1 is a schematic cross-sectional view of a polarizing plate laminate of the present invention.

Referring to Figure 1, the polarizing plate laminate 100 of the present invention includes a polarizing plate 20, a hard coating layer 30 provided on the top surface of the polarizing plate 20; and an adhesive layer 10 provided on a lower surface of the polarizing plate. In this case, the adhesive layer 10 may be omitted.

Referring to FIG. 2 , the polarizer 20 includes a polarizer 21 and a protective film 23 . An adhesive layer 22 may be provided between the polarizer 21 and the protective film 23 to bond the polarizer and the protective film.

Referring to FIG. 3 , the polarizer stack 100 may be adhered to the display panel 40 through the adhesive layer 10 .

The polarizer 20 may emit light incident from the display panel 40 .

The adhesive layer may use a conventional adhesive.

The adhesive layer may use a conventional adhesive, and may be formed from a composition for an adhesive layer containing an adhesive resin such as a (meth)acrylic resin, an epoxy resin, a silicone resin, and a curing agent or a coupling agent.

The display panel 40 may be a liquid crystal panel of a twisted nematic (TN) mode, an in-plane switching (IPS) mode, a fringe field switch (FFS) mode, or a vertical alignment (VA) mode. The liquid crystal panel may include an upper substrate, a lower substrate, and a liquid crystal layer sealed between the upper and lower substrates.

The upper substrate and the lower substrate may be the same or different, and each may be a glass substrate or a plastic substrate. The plastic substrate may include polyethyleneterephthalate (PET), polycarbonate (PC), polyimide (PI), polyethylenenaphthalate (PEN), polyethersulfone (PES), polyarylate (PAR), and cycloolefin copolymer (COC), which may be used in a flexible display. It may be a plastic substrate, but the present invention is not limited thereto.

The liquid crystal layer may include liquid crystal having a positive or negative dielectric constant anisotropy. The dielectric constant anisotropy of the liquid crystal layer may be appropriately selected according to a desired mode of the liquid crystal panel. In one example, the in-plane retardation value of the liquid crystal layer may be 270 nm to 330 nm, and the retardation value in the thickness direction may be 0 nm to -40 nm.

The upper and lower substrates of the liquid crystal panel may further include alignment layers toward the liquid crystal layer. The alignment direction of the liquid crystal may be determined by the alignment layer. The alignment layer may be a horizontal alignment layer. A rubbing alignment layer or an optical alignment layer may be used as the alignment layer.

hard coating layer

The hard coating layer 30 is provided on the uppermost surface of the polarizing plate 20 and serves to effectively protect the internal components of the image display device, particularly the polarizing plate 20 .

The hard coating layer 30 has excellent physical durability and/or chemical durability, and has excellent optical characteristics.

The hard coating layer 30 may be directly provided on one side or both sides of the polarizer. The “directly provided” means that no other layer is provided between the hard coating layer and the polarizer.

That is, the polarizer 20 may include a polarizer 21 , and the hard coating layer 30 may be directly provided on an uppermost surface of the polarizer 21 . At this time, it means that no other layer is provided between the hard coat layer 30 and the polarizer 21 .

The maximum value of the loss tangent coefficient tanδ of the hard coating layer 30 may be 0.5 or less, or 0.4 or less, preferably 0.35 or less, and more preferably 0.33 or less. When the above range is satisfied, heat resistance and durability of the hard coating layer may be excellently maintained.

The tan δ (tan Delta) means the ratio of the storage modulus and the loss modulus. Specifically, the tan δ (tan Delta) can be represented by the following formula.

tanδ(tan Delta) = storage modulus / loss modulus

In order to measure the tanδ (tan Delta), first, the same composition as the hard coating layer composition was coated on the release film, and a cured film was prepared by irradiating a light amount of 1,000 mJ / cm ² at a temperature of 23 ° C and a relative humidity of 55%. do. At this time, the thickness of the cured film is 30 μm to 50 μm, and may be, for example, 30 μm. After removing the release film, a specimen manufactured in the size of width x length x thickness (5.3mm x 10mm x 30㎛) was subjected to a temperature sweep test (Amplitude 10㎛, Preload force 0.01N, Force Track 125%, Frequency 1Hz), measure the storage modulus while raising the temperature from -10 ℃ to 160 ℃ at 5 ℃ / min. Record the measured storage modulus divided by the measured loss modulus, and calculate tan Delta (tanδ) at the maximum value.

The maximum value of the loss tangent coefficient tanδ of the hard coating layer 30 appears in the temperature range of 90 ° C to 120 ° C, preferably in the temperature range of 95 ° C to 120 ° C, more preferably in the temperature range of 100 ° C to 120 ° C can A temperature at which the maximum value of the loss tangent coefficient tanδ appears may be defined as Tmax.

Since the hard coating layer 30 serves to protect other components, the protection function improves as the thickness increases, but the optical properties may deteriorate. Therefore, it is important to adjust the thickness within a certain range to secure a protective function and prevent optical properties from deteriorating. Specifically, the hard coating layer may have a thickness of 5 μm to 15 μm, preferably 5 μm to 10 μm, and more preferably 6 μm to 9 μm. When the thickness exceeds 15 μm, there is a problem in that the optical properties of the hard coating layer are impaired, and when the thickness of the hard coating layer is less than 5 μm, the protective function is deteriorated, resulting in a decrease in high temperature or high humidity durability.

In addition, the thickness of the hard coating layer 30 can be measured using FESEM SU-8020 SYSTEM equipment for the cross section of the image display device (measurement conditions: acceleration voltage 2 kV, emission current: 10uA, working distance: 8mm, detector :SE).

The hard coating layer 30 has a low moisture permeability characteristic. Specifically, the water vapor transmission rate (WVTR) of the hard coating layer is 200 g/m ² *day or less, preferably 150 g/m ² *day or less, more preferably 120 g/m ² *day or less at a temperature of 38 °C. can

The moisture permeability means the amount of moisture passing per unit time and unit area in a constant external environment, and can be measured in an environment where the difference between the inside and outside of the film is 90%. name: WVTR TSY-T3). The equipment has a structure in which a scale is placed in a sealed chamber, and the environment in the chamber is maintained at 38° C. and 10% humidity. In addition, after pouring water into the moisture permeable cup, a specimen having the same composition as the hard coating layer is covered and fixed thereon. Since the humidity inside the moisture permeable cup is 100% because it is full of water, the difference between the humidity inside and outside the moisture permeable cup is 90%. After 24 hours, the weight of the moisture permeable cup can be measured and the amount of evaporated water can be calculated through the difference from the initial weight.

The hard coating layer 30 has a low absolute value of the photoelastic coefficient. Specifically, the hard coating layer 30 has an absolute value of photoelastic coefficient of 12 x 10 ^-12 m ² /N or less, preferably 11 x 10 ^-12 m ² /N or less, more preferably 10.8 x 10 ^-12 m ² /N or less. If the above range is exceeded, there is a problem in that optical distortion occurs due to stress under high temperature and high humidity conditions, resulting in light leakage.

The photoelastic coefficient is defined as the degree of expression of birefringence (Δn) with respect to stress (ΔF) applied to an isotropic solid (relational expression: c=Δn/ΔF). As a measurement method, a specimen having the same composition as the hard coating layer is cut into a size of 40 to 50 μm thick and 15 mm wide X 100 mm long, and then using a polarization spectrophotometer at a temperature of 25 ° C and a relative humidity of 50%. can be measured by After fixing both end surfaces of the specimen to a support, birefringence according to a change in load (stress) is measured, and the photoelastic coefficient is measured from the slope.

The hard coating layer 30 has excellent strength against external impact. Specifically, the hard coating layer may have a pencil hardness of HB or more and 9H or less, preferably 1H or more and 9H or less. The pencil hardness of the hard coating layer can be measured by the test method of JIS K 5600 5-4. After preparing a specimen having the same composition as the hard coating layer, a pencil lead having the hardness to be measured is fixed on a pencil hardness tester. Thereafter, the tip of the pencil lead of the hardness to be measured is trimmed flat, and the pencil lead is placed on the specimen so that the end surface of the pencil lead and the surface of the specimen form an angle of 45 degrees. After installing a weight so that a load of 500g is applied to the tip of the pencil lead, inspect the surface with the naked eye while moving the pencil at a speed of 5mm/sec.

The storage modulus of the hard coating layer 30 at 80° C. is preferably 800 Mpa to 10,000 Mpa, more preferably 1,000 Mpa to 5,000 Mpa, and most preferably 1,500 Mpa to 3,500 Mpa. When the storage modulus of the hard coating layer satisfies the above numerical range, there is an effect that can effectively suppress cracking of the polarizer due to contraction or expansion of the polarizer in a high temperature or high humidity environment. In addition, adhesion to the polarizing plate can be improved. Therefore, by suppressing contraction and expansion of the polarizing plate at high temperature, it is possible to prevent light leakage as well as excellent adhesive strength.

The hard coating layer 30 may have a refractive index of 1.4 or more and 1.5 or less at the D-line wavelength. In this case, the light source of the D-line wavelength may be an LED lamp.

The hard coating layer 30 may be formed by coating and curing a photocurable composition on the upper surface of the polarizing plate 20 . That is, the hard coating layer 30 may include a cured product of the photocurable composition. The photocurable composition means a composition that is cured by irradiation of light.

Meanwhile, the coating method is not particularly limited, and may be formed by a method well known in the art. For example, the photocurable composition is applied to at least one surface of the polarizer by a coating method well known in the art, such as spin coating, bar coating, roll coating, gravure coating, blade coating, etc. to form a hard coating layer Next, it may be formed by a method of irradiating ultraviolet light, which is irradiation light, using an ultraviolet irradiation device.

The wavelength of the ultraviolet rays is preferably 100 nm to 400 nm, more preferably 320 nm to 400 nm. In addition, the amount of irradiation light is preferably 100 mJ/cm ² to 1,000 mJ/cm ² , and more preferably 500 mJ/cm ² to 1,000 mJ/cm ² .

The irradiation time of the irradiation light is preferably 1 second to 10 minutes, more preferably 2 seconds to 30 seconds. When the irradiation time range is satisfied, there is an advantage in that it is possible to prevent excessive heat transfer from the light source, thereby minimizing the occurrence of traveling wrinkles in the polarizer.

The hard coating layer includes a polysiloxane compound. That is, the hard coating layer may include a photocurable composition including a polysiloxane compound. The polysiloxane compound lowers the surface energy of the hard coating layer, and has an effect of suppressing a blocking phenomenon in which the hard coating layer and the processing film adhere to each other when a process film is laminated on the hard coating layer. In addition, since the polysiloxane compound has high binding energy, it has excellent heat resistance.

The hard coating layer may include a polysiloxane compound having a cyclic polysiloxane structure. That is, the polysiloxane compound may have a cyclic polysiloxane structure. In the present specification, "cyclic polysiloxane structure" means a structure having two or more siloxane units (Si-O-Si) in a ring component. When the polysiloxane compound includes a cyclic polysiloxane structure, it has excellent heat resistance compared to the case where the polysiloxane compound includes a linear polysiloxane structure. Specifically, by including the ring structure in the molecular structure, the crosslinking density of the cured product may be increased to improve high-temperature durability. In addition, due to the water repellency inherent in siloxane, it is possible to improve the protective function of the hard coating layer in a high humidity environment. That is, the polysiloxane compound may improve durability in a high temperature and high humidity environment by including a cyclic polysiloxane structure.

The polysiloxane compound may include a cyclic polysiloxane structure in a main chain or a side chain, preferably in a main chain. In this case, it has the advantage of excellent heat resistance.

The polysiloxane compound may include two or more cationically polymerizable functional groups. In this case, the cationically polymerizable functional groups may be the same as or different from each other.

The cationically polymerizable functional group may be an epoxy group, a vinyl ether group, an oxetane group or an alkoxysilyl group, and an epoxy group is preferable. The epoxy group may be an alicyclic epoxy group.

The above polysiloxane compound is commercially available "KR-470" [tetrafunctional epoxycyclic siloxane compound: manufactured by Shin-Etsu Chemical Co., Ltd.] and "X-40-2678" [bifunctional epoxycyclic siloxane compound: manufactured by Shin-Etsu Chemical Co., Ltd.] etc. can be mentioned.

The content of the polysiloxane compound may be 6 parts by weight or more and 50 parts by weight based on 100 parts by weight of the hard coating layer. The lower limit may be 8 parts by weight or more, more preferably 10 parts by weight or more. In addition, the upper limit may be 50 parts by weight or less, preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and most preferably 10 parts by weight or more and 20 parts by weight or less. 100 parts by weight of the hard coating layer may be based on 100 parts by weight of the solid content of the photocurable composition for forming the hard coating layer. When the above range is satisfied, there is an effect of improving the heat resistance of the hard coating layer.

The photocurable composition for forming the polarizing plate hard coat layer may be a cationic photocurable composition. That is, the hard coating layer may include a cured product of a cationic photocurable composition.

The hard coating layer may include a cured product of a photocurable composition including an epoxy compound and an oxetane compound. That is, the photocurable composition may include an epoxy compound and an oxetane compound.

The epoxy compound is for lowering the thermal expansion coefficient after curing of the composition, and includes an alicyclic epoxy compound, an aliphatic epoxy compound, an aromatic epoxy compound, a hydrogenated epoxy compound, or an epoxy group-containing (meth)acrylic compound. These can be used individually or in mixture of 2 or more.

The alicyclic epoxy compound includes one or more alicyclic epoxy rings, and refers to a compound in which an epoxy group is formed between two adjacent carbon atoms constituting an aliphatic ring. For example, dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 2,4-epoxycyclohexylmethyl, 3,4-epoxycyclohexanecarboxylate, dicyclopentadiene dioxide, bis(3, 4-epoxycyclohexylmethyl) adipate and the like, but is not limited thereto. In addition, 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexane carboxylate is preferred for lowering the thermal expansion coefficient after curing of the composition and imparting hardness to the adhesive layer formed from the composition. do.

Examples of the aliphatic epoxy compound include novolak epoxy, bisphenol A epoxy, bisphenol F epoxy, 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexane Diol diglycidyl ether, neopentyl diglycidyl ether, resorcinol diglycidyl ether, diethylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, n -Butyl glycidyl ether, 2-ethylhexyl glycidyl ether, etc. are mentioned.

The aromatic epoxy compound refers to an epoxy compound containing at least one aromatic hydrocarbon ring in a molecule, but is not limited thereto, for example, diglycidyl ether of bisphenol A, 4,4'-methylenediphenol diglyceride bisphenol-type epoxy resins such as cydyl ether, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; novolak-type epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, and hydroxybenzaldehyde phenol novolac epoxy resins; and polyfunctional epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, and epoxidized polyvinylphenol.

The hydrogenated epoxy compound refers to an epoxy compound obtained by selectively hydrogenating the aromatic epoxy compound under pressure in the presence of a catalyst, but is not limited thereto, and among these, diglycidyl ether of hydrogenated bisphenol A It is preferable to use

The epoxy group-containing (meth)acrylic compound refers to a compound containing both an epoxy group and a (meth)acryloyloxy group in a molecule, but is not limited thereto, for example, glycidyl acrylate, 2-methylglycine Dill acrylate, 3,4-epoxybutyl acrylate, 6,7-epoxyheptyl acrylate, 3,4-epoxycyclohexyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, 3 , 4-epoxybutyl methacrylate, 6,7-epoxyheptyl methacrylate, 3,4-epoxycyclohexyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, and the like.

The epoxy compound may be an epoxy compound containing one or more alicyclic epoxy groups.

The epoxy compound including one or more alicyclic epoxy groups has two or more epoxy groups in a molecule, and at least one of the epoxy groups may be an alicyclic epoxy group. The epoxy compound containing one or more alicyclic epoxy groups may improve adhesive strength to other members of the composition. In addition, the glass transition temperature of the composition is increased to ensure sufficient durability of the adhesive layer, and cracking of the polarizer can be prevented even under heat resistance or thermal shock conditions.

The epoxy compound including one or more alicyclic epoxy groups may have substantially no aromatic ring. In this case, photocuring efficiency can be improved, and optical properties after curing such as weather resistance and refractive index can be improved.

The epoxy compound including one or more alicyclic epoxy groups may have two or more epoxy groups in a molecule, and all of the epoxy groups may be alicyclic epoxy groups. In this case, the adhesive strength of the adhesive composition to other members can be further improved.

The number of carbon atoms in the alicyclic ring of the epoxy compound including one or more alicyclic epoxy groups may be 4 to 10, preferably 6.

The alicyclic ring of the epoxy compound including one or more alicyclic epoxy groups may be substituted or unsubstituted, and examples of the substituent include an alkyl group having 1 to 20 carbon atoms. In the carbon number range, the curing rate and adhesive strength after curing may be improved. Unless otherwise specified, the alkyl group may mean a straight-chain, branched-chain or cyclic alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, and , The alkyl group may be optionally substituted by one or more substituents, or may be unsubstituted.

The epoxy compound containing one or more alicyclic epoxy groups includes one or more alicyclic epoxy rings, means a compound in which an epoxy group is formed between two adjacent carbon atoms constituting an aliphatic ring, and an alicyclic epoxy compound. It may be named, and as shown in Formula (a1) below, it may be a compound having at least one epoxy group bonded to an alicyclic ring in a molecule.

[Formula a1]

In Formula (a1), m is an integer of 2 to 5, and in Formula (a1), a compound obtained by removing one or a plurality of hydrogen atoms in (CH ₂ )m bonded to another chemical structure without an aromatic ring is an alicyclic epoxy compound. can That is, it may mean a compound containing one or more epoxidized aliphatic ring groups.

Examples of the epoxy compound containing one or more alicyclic epoxy groups may be represented by the following chemical formula, but are not limited thereto.

As the epoxy compound containing at least one alicyclic epoxy group, an epoxycyclohexylmethyl epoxycyclohexanecarboxylate-based compound represented by Formula 1 below may be exemplified.

[Formula 1]

In Formula 1, R ₁ and R ₂ each independently represent hydrogen or an alkyl group.

As another example of the epoxy compound containing at least one alicyclic epoxy group, an epoxycyclohexane carboxylate-based compound of an alkanediol represented by the following Chemical Formula 2 may be mentioned.

[Formula 2]

In Formula 2, R ₃ and R ₄ each independently represent hydrogen or an alkyl group, and n represents an integer of 2 to 20.

As another example of the epoxy compound containing at least one alicyclic epoxy group, an epoxy cyclohexylmethyl ester-based compound of dicarboxylic acid represented by Formula 3 below may be mentioned.

[Formula 3]

In Formula 3, R ₅ and R ₆ each independently represent hydrogen or an alkyl group, and p represents an integer of 2 to 20.

As another example of the epoxy compound containing at least one alicyclic epoxy group, an epoxycyclohexylmethyl ether-based compound of polyethylene glycol represented by the following Chemical Formula 4 may be mentioned.

[Formula 4]

In Formula 4, R ₇ and R ₈ each independently represent hydrogen or an alkyl group, and q represents an integer of 2 to 20.

As another example of the epoxy compound containing at least one alicyclic epoxy group, an epoxycyclohexylmethyl ether-based compound of alkanediol represented by the following Chemical Formula 5 may be mentioned.

[Formula 5]

In Formula 5, R ₉ and R ₁₀ each independently represent hydrogen or an alkyl group, and r represents an integer of 2 to 20.

As another example of the epoxy compound containing at least one alicyclic epoxy group, a diepoxytrispiro-based compound represented by the following Chemical Formula 6 may be mentioned.

[Formula 6]

In Formula 6, R ₁₁ and R ₁₂ each independently represent hydrogen or an alkyl group.

As another example of the epoxy compound containing at least one alicyclic epoxy group, a diepoxymonospiro-based compound represented by the following Chemical Formula 7 may be mentioned.

[Formula 7]

In Formula 7, R ₁₃ and R ₁₄ each independently represent hydrogen or an alkyl group.

As another example of the epoxy compound containing at least one alicyclic epoxy group, a vinylcyclohexene diepoxide compound represented by the following Chemical Formula 8 may be mentioned.

[Formula 8]

In Formula 8, R ₁₅ represents hydrogen or an alkyl group.

As another example of the epoxy compound containing at least one alicyclic epoxy group, an epoxycyclopentyl ether compound represented by the following Chemical Formula 9 may be mentioned.

[Formula 9]

In Formula 9, R ₁₆ and R ₁₇ each independently represent hydrogen or an alkyl group.

As another example of the epoxy compound containing at least one alicyclic epoxy group, a diepoxy tricyclodecane compound represented by the following Chemical Formula 10 may be mentioned.

[Formula 10]

In Formula 10, R ₁₈ represents hydrogen or an alkyl group.

Other examples of the epoxy compound containing at least one alicyclic epoxy group include, more specifically, an epoxycyclohexylmethyl epoxycyclohexane carboxylate compound, an alkanediol epoxycyclohexane carboxylate compound, and a dicarboxylic acid epoxycyclohexylmethyl ester compound. or an epoxycyclohexylmethyl ether compound of an alkanediol is preferably used, and 7-oxabicyclo[4,1,0]heptane-3-carboxylic acid and (7-oxa-bicyclo[4,1,0]hepto -3-yl) esterified with methanol (a compound in which R ₁ and R ₂ are hydrogen in Formula 1 above); Esters of 4-methyl-7-oxabicyclo[4,1,0]heptane-3-carboxylic acid with (4-methyl-7-oxa-bicyclo[4,1,0]hepto-3-yl)methanol Cargo (a compound in Formula 1, wherein R ₁ is 4-CH ₃ and R ₂ is 4-CH ₃ ); an esterified product of 7-oxabicyclo[4,1,0]heptane-3-carboxylic acid and 1,2-ethanediol (a compound in which R ₃ and R ₄ are hydrogen and n is 2 in Formula 2); (7-oxabicyclo[4,1,0]hepto-3-yl)an ester of methanol and adipic acid (a compound in Formula 3 wherein R ₅ and R ₆ are hydrogen and p is 2); (4-methyl-7-oxabicyclo[4,1,0]hepto-3-yl) an ester of methanol and adipic acid (in Formula 3, R ₅ and R ₆ are 4-CH ₃ , and p is 2 compounds); and (7-oxabicyclo[4,1,0]hepto-3-yl)methanol and 1,2-ethanediol etherified compounds (in Formula 5, R ₉ and R ₁₀ are hydrogen and r is 2). ) One or more selected from the group consisting of may be preferably used, but is not limited thereto.

The epoxy compound containing one or more alicyclic epoxy groups increases the glass transition temperature (Tg) of the composition and imparts strength to the adhesive layer formed from the composition, 3,4-epoxycyclohexylmethyl- 3,4'-epoxycyclohexanecarboxylate is preferred.

The oxetane compound is not particularly limited as long as it has at least one oxetanyl group in its molecule, and various oxetane compounds well known in the art may be used. For example, as the oxetane compound of the present invention, 3-ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane, 1,4-bis[(3-ethyloxetane) Cetan-3-yl) methoxymethyl] benzene, 1,4-bis [(3-ethyloxetan-3-yl) methoxy] benzene, 1,3-bis [(3-ethyloxetan-3-yl) ) methoxy] benzene, 1,2-bis [(3-ethyloxetan-3-yl) methoxy] benzene, 4,4'-bis [(3-ethyloxetan-3-yl) methoxy] b Phenyl, 2,2'-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 3,3',5,5'-tetramethyl-4,4'-bis[(3-ethyl Oxetan-3-yl) methoxy] biphenyl, 2,7-bis [(3-ethyloxetan-3-yl) methoxy] naphthalene, bis [4-{(3-ethyloxetan-3-yl )methoxy}phenyl]methane, bis[2-{(3-ethyloxetan-3-yl)methoxy}phenyl]methane, 2,2-bis[4-{(3-ethyloxetan-3-yl ) methoxy} phenyl] propane, 3-chloromethyl-3-ethyloxetane etherification modified product of novolak-type phenol-formaldehyde resin, 3(4),8(9)-bis[(3-ethyl Oxetan-3-yl) methoxymethyl] -tricyclo [5.2.1.0 2,6 ] decane, 2,3-bis [(3-ethyloxetan-3-yl) methoxymethyl] norbornane, 1 ,1,1-tris[(3-ethyloxetan-3-yl)methoxymethyl]propane, 1-butoxy-2,2-bis[(3-ethyloxetan-3-yl)methoxymethyl] Butane, 1,2-bis[{2-(3-ethyloxetan-3-yl)methoxy}ethylthio]ethane, bis[{4-(3-ethyloxetan-3-yl)methylthio}phenyl ] sulfide, 1,6-bis [(3-ethyloxetan-3-yl) methoxy] -2,2,3,3,4,4,5,5-octafluorohexane, etc., but this It is not limited.

The photocurable composition may further include a photoinitiator, a photosensitizer, or a photosensitizer.

The photoinitiator may be an iodine-based compound that absorbs a wavelength of 310 nm or less. Specifically, the photoinitiator refers to an iodine-based compound that is activated by absorbing a wavelength of 310 nm or less and produces a cation or a Lewis acid by irradiation of active energy. For example, diphenyliodonium hexafluorophosphate (Iod-PF ₆ ), diphenyliodonium triflate (Iod-OSO ₂ CF ₃ ), diphenyliodonium p-toluenesulfonate (Iod-OSO ₂ PhCH ₃ ), diphenyliodonium chloride (Iod-Cl), [4-methylphenyl-(4-(2-methylpropyl)phenyl)]iodonium hexafluorophosphate (Irgacure 250), and the like, [4- Methylphenyl-(4-(2-methylpropyl)phenyl)]iodonium hexafluorophosphate (Irgacure 250) is preferred, but not limited thereto.

The amount of the photoinitiator is preferably 2 to 5 parts by weight, more preferably 2.5 to 3.5 parts by weight, based on 100 parts by weight of the total photocurable composition. When the photoinitiator is included in an amount within the above numerical range, UV rays can effectively reach the inside of the hard coating layer, the polymerization rate is excellent, and the molecular weight of the resulting polymer can be prevented from being reduced. Therefore, there is an advantage in that the cohesive strength of the formed hard coating layer and the adhesive strength to the polarizer are excellent.

The photocurable composition includes a photosensitizer. The photosensitizer may be a thioxanthone-based photosensitizer.

Examples of the thioxanthone-based photosensitizer include an alkylthioxanthone-based, alkoxythioxanthone-based, or halothioxanthone-based photosensitizer. The specific structure is shown in Formula B below.

[Formula B]

In Formula B, R ₁ 'to R ₈ ' are the same or different, and each independently hydrogen; halogen group; A substituted or unsubstituted alkyl group; Or it may be a substituted or unsubstituted alkoxy group.

In Formula B, R ₁ 'to R ₈ ' are the same or different, and each independently hydrogen; halogen group; A substituted or unsubstituted alkyl group having 1 to 8 carbon atoms; Or it may be a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms.

More specific examples of the thioxanthone-based photosensitizer are 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1 -Chloro-4-propoxythioxanthone etc. are mentioned.

The amount of the photosensitizer may be 0.01 to 0.4 parts by weight, preferably 0.1 to 0.3 parts by weight, based on 100 parts by weight of the total photocurable composition. When the photosensitizer is included in the above numerical range, it receives ultraviolet rays of 380 nm or more to help the photoinitiator of 310 nm or less to initiate efficiently, and is effectively cured to the inside of the hard coating layer to have excellent polymerization rate, and the resulting polymer It is possible to prevent a decrease in the molecular weight of

The photocurable composition further includes a photosensitizing agent. Specifically, the photosensitizing agent may be a naphthalene-based compound.

The photosensitizing agent may be a compound represented by Formula C below.

[Formula C]

In the above formula C,

R ₁₁ ' and R ₁₂ ' are the same as or different from each other, and are each independently an alkyl group having 1 to 6 carbon atoms.

Types of the photosensitizer include 1,4-dimethoxy naphthalene, 1-ethoxy-4-methoxy naphthalene, 1,4-diethoxy naphthalene, 1,4-dipropoxy naphthalene, 1,4-dibutoxy naphthalene, etc.

The amount of the photosensitizing aid is preferably 1 to 3 parts by weight, more preferably 1 to 2 parts by weight, based on 100 parts by weight of the total photocurable composition. When the photosensitizer is included in an amount within the above numerical range, the photosensitizer is excited to help initiate the photoinitiator. Specifically, the anthracene-based photosensitizer excited by receiving ultraviolet rays of 380 nm or more immediately transfers energy to the photosensitizer, and the excited photosensitizer transfers energy so that the photoinitiator can be efficiently initiated. Due to this, it can effectively reach the inside of the hard coating layer, has an excellent polymerization rate, and can prevent the molecular weight of the resulting polymer from decreasing. Therefore, there is an advantage in that the cohesive strength of the formed hard coating layer and the adhesive strength to the polarizer are excellent.

The photocurable composition may further include at least one of a dye, a pigment, a UV stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, and a plasticizer, if necessary.

The photocurable composition preferably has a glass transition temperature of 90°C or more and 130°C or less after curing, and may be 100°C to 130°C. When having a glass transition temperature in the numerical range as described above, it is possible to implement a hard coating layer having excellent durability even under a high temperature environment.

In the present specification, the glass transition temperature is applied to a release film (eg, polyethylene terephthalate film) with a thickness of 50 μm, cured by irradiation with ultraviolet rays under conditions of a light amount of 1000 mJ / cm ² or more, and then removing the release film, After laser cutting the specimen to a certain size, it is measured through DMA (dynamic mechanical analysis). At this time, the measured temperature is raised from the starting temperature of -10 ° C to 160 ° C at a heating rate of 5 ° C / min, and the glass transition temperature is confirmed through the inflection of the storage modulus when constantly tensile with a strain of 10%.

The viscosity of the photocurable composition at 25°C is preferably 50 cps or more and 200 cps or less, more preferably 50 cps or more and 130 cps. When the viscosity of the photocurable composition satisfies the above numerical range, it is possible to form a thin hard coating layer and has excellent workability. The viscosity can be measured at room temperature using a Brookfield viscometer using a No. 18 spindle. At this time, the appropriate amount of the composition is 6.5 to 10 mL, and the stabilized value is measured within 5 minutes to avoid exposure to light for a long time.

The polarizer may use a polarizer well known in the art, for example, a film made of polyvinyl alcohol (PVA) containing iodine or a dichroic dye. The polarizer may be manufactured by dyeing a polyvinyl alcohol-based film with iodine or a dichroic dye, but a manufacturing method thereof is not particularly limited. In this specification, the polarizer means a state that does not include a hard coating layer (or protective film), and the polarizer means a state that includes a polarizer and a hard coating layer (or protective film).

The polarizing plate includes a step of uniaxially stretching a polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, and a polyvinyl alcohol-based resin film adsorbed with the dichroic dye. It is manufactured through a process of treating with an aqueous solution of boric acid, a process of washing with water after treatment with an aqueous solution of boric acid, and a process of bonding a hard coating layer to a uniaxially stretched polyvinyl alcohol-based resin film in which dichroic dyes are adsorbed and oriented through these processes.

The uniaxial stretching may be performed before dyeing with the dichroic dye, simultaneously with dyeing with the dichroic dye, or after dyeing with the dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, this uniaxial stretching may be performed before boric acid treatment or may be performed during boric acid treatment. Moreover, it is also possible to perform uniaxial stretching in these several steps. In order to perform uniaxial stretching, uniaxial stretching may be performed between rolls having different circumferential speeds, or uniaxial stretching may be performed using a hot roll. Further, dry stretching performed in air may be used, or wet stretching performed in a state swollen with a solvent may be used. The stretching ratio is not particularly limited, but is usually 4 to 8 times.

On the other hand, the polarizer preferably has a thickness of 5 μm to 40 μm, more preferably 5 μm to 25 μm. If the thickness of the polarizer is thinner than the above numerical range, the optical properties may be deteriorated, and if the thickness of the polarizer is thicker than the above numerical range, the amount of polarizer shrinkage at low temperature (eg, -30 ° C.) increases, thereby weakening the heat-related durability of the polarizer as a whole. .

In addition, when the polarizer is a polyvinyl alcohol-based film, the polyvinyl alcohol-based film can be used without particular limitation as long as it includes a polyvinyl alcohol resin or a derivative thereof. In this case, as the derivative of the polyvinyl alcohol resin, there are polyvinyl formal resin, polyvinyl acetal resin, etc., but are not limited thereto. In addition, commercially available polyvinyl alcohol-based films such as P30, PE30, and PE60 from Kuraray and M2000, M3000, and M6000 from Nihon Synthetic Co. may be used, but are not limited thereto.

The polyvinyl alcohol-based film preferably has a polymerization degree of 1,000 to 10,000, more preferably 1,500 to 5,000. When the degree of polymerization satisfies the above numerical range, the molecules are free to move and can be flexibly mixed with iodine or dichroic dyes.

The polarizing plate laminate may further include an adhesive layer provided on a lower surface of the polarizing plate.

The polarizing plate laminate may further include a protective film provided between the polarizing plate and the adhesive layer.

The protective film 23 may be a retardation film. That is, the polarizing plate laminate may further include a retardation film provided between the polarizing plate and the adhesive layer.

An in-plane retardation value and a thickness direction retardation value of the protective film 23 may be 0.1 to 150 nm, respectively.

Each of the protective films 23 may be a polymer film. As the polymer film, for example, a polyolefin film such as a polyethylene film or a polypropylene film, a cycloolefin polymer (COP) film such as a polynorbornene film, a polyvinyl chloride film, a polyacrylonitrile film, a poly A cellulose ester-based polymer film such as a sulfone film, a polyacrylate film, a polyvinyl alcohol film, or a triacetyl cellulose (TAC) film, or a copolymer film of two or more types of monomers forming the polymer may be exemplified.

The polymer film may use a resin containing a substituted or unsubstituted styrene group in the main chain and/or a blend containing the resin. More specifically, the resin containing the substituted or unsubstituted styrene group includes styrene-acrylonitrile copolymer (SAN), methyl methacrylate-styrene (MS), styrene-maleic anhydride (SMA), styrene-maleic anhydride- A resin containing a methyl methacrylate copolymer can be used. More specifically, the polymer film may include an acrylic resin including a resin containing a substituted or unsubstituted styrene group. As the acrylic resin, an acrylic resin composed of methacrylic acid ester and acrylic acid ester may be used. The acrylic resin may include an acrylic copolymer resin having a ring structure such as N-substituted maleimide, lactone ring, glutalimide, or maleic anhydride. The glass transition temperature of the resin included in the polymer film may be 100°C or higher, preferably 110°C or higher. The polymer film may have a thickness of 80 μm or less. The polymer film may be produced through extrusion or casting, followed by biaxial stretching (simultaneous or sequential).

The present invention is an image display panel; And it provides an image display device comprising the above-described polarizing plate laminate on one side or both sides of the image display panel. In this case, the polarizing plate laminate may further include an adhesive layer provided on a lower surface of the polarizing plate, and the adhesive layer of the polarizing plate laminate may be adhered to the image display panel.

In the present specification, the image display device may be a liquid crystal display (LCD), a plasma display (PDP), and an organic light emitting display (OLED).

The image display panel may be a liquid crystal panel. At this time, the type of the liquid crystal panel is not particularly limited. For example, a passive matrix type panel such as a twisted nematic (TN) type, a super twisted nematic (STN) type, a ferroelectic (F) type, or a polymer dispersed (PD) type; an active matrix type panel such as a two terminal type or a three terminal type; In-Plane Switching (IPS) panels and Vertical Alignment (VA) panels, but are not limited thereto. In addition, other components constituting the liquid crystal display, for example, upper and lower substrates (eg, color filter substrates or array substrates), etc. are not particularly limited.

Hereinafter, examples will be described in detail in order to specifically describe the present specification. However, the embodiments according to the present specification may be modified in many different forms, and the scope of the present invention is not construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present specification to those skilled in the art.

<Experimental example>

A photocurable composition having the composition shown in Table 1 below was prepared. Photocurable compositions 1 and 2 contain a polysiloxane compound, but photocurable composition 3 does not contain a polysiloxane compound.

Furtherance Photocurable Composition 1 Photocurable Composition 2 Photocurable composition 3 1st epoxy compound 40 50 65 Second Epoxy Compound 0 0 20 oxetane compound 20 20 15 Cyclic polysiloxane compound 40 (KR-470) 0 0 linear polysiloxane compound 0 30 (KR-517) 0 Photoinitiator (Irgacure 250) 2-3 2-3 2-3 Photoinitiator (ITX) 1~2 1~2 1~2

선형 폴리실록산 화합물: (KR-517, Shin-Etsu사 제조)

상기 수치값은 각 성분의 중량비를 나타냄.
광개시제의 수치값은 에폭시 화합물, 옥세탄 화합물 및 폴리실록산 화합물의 총 중량에 대한 각 성분의 중량비를 의미함.First epoxy compound: (3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, trade name: CEL-2021P, manufactured by Daicel Corporation)
Second epoxy compound: (1,4-cyclohexanedimethanol diglycidyl ether, trade name: LD-204)
Oxetane compound: (3-ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane, trade name: OXT-221, manufactured by Toagosei Co., Ltd.)
Cyclic polysiloxane compound: (trade name: KR-470, manufactured by Shin-Etsu)
KR-470 structure

Linear polysiloxane compound: (KR-517, manufactured by Shin-Etsu)

The numerical value represents the weight ratio of each component.
The numerical value of the photoinitiator means the weight ratio of each component to the total weight of the epoxy compound, oxetane compound and polysiloxane compound.

<Manufacture of polarizing plate laminate>

<Example 1>

A hard coating layer (thickness: 6 μm) was formed on the top surface of the polarizer by applying and curing the photocurable composition 1 on the upper surface of the polyvinyl alcohol-based film polarizer (PVA). Thereafter, a retardation film (TAC, thickness: 40 μm) was bonded to the lower surface of the polarizer using UV adhesive, and an adhesive was applied to the opposite side of the retardation film facing the polarizer to prepare a polarizing plate laminate.

<Example 2>

A polarizing plate laminate was prepared in the same manner as in Example 1 except for using photocurable composition 2 instead of photocurable composition 1.

<Comparative Example 1>

A polarizing plate laminate was prepared in the same manner as in Example 1, except that photocurable composition 3 was used instead of photocurable composition 1.

<Comparative Example 2>

Instead of forming a hard coating layer on the top surface of the polarizer, a protective film (TAC, 60㎛) is laminated using UV adhesive, and the photocurable composition 1 is applied instead of the retardation film on the lower surface of the polarizer to form a protective layer (thickness: 12㎛). ) was formed, and a polarizing plate laminate was prepared by applying an adhesive to the opposite side of the protective layer facing the polarizer.

<Comparative Example 3>

Instead of forming a hard coating layer on the top surface of the polarizer, a protective film (TAC, 60㎛) is laminated using UV adhesive, and the photocurable composition 3 is applied instead of the retardation film on the lower surface of the polarizer to form a protective layer (thickness: 12㎛). ) was formed, and a polarizing plate laminate was prepared by applying an adhesive to the opposite side of the protective layer facing the polarizer.

<Comparative Example 4>

Instead of forming a hard coating layer on the top surface of the polarizer, a protective film (PET, 60㎛) is laminated using UV adhesive, and the photocurable composition 3 is applied instead of the retardation film on the lower surface of the polarizer to form a protective layer (thickness: 12㎛). ) was formed, and a polarizing plate laminate was prepared by applying an adhesive to the opposite side of the protective layer facing the polarizer.

<Experimental example>

1. Measurement of dynamic thermal properties of hard coating layer

Specimens having the same composition as the hard coating layer of the polarizing plate laminate were prepared and the dynamic thermal characteristics of the hard coating layer were analyzed. At this time, a dynamic mechanical analysis (DMA) from TA Instruments was used, and the storage modulus (Mpa) and loss modulus (Loss Modulus, Mpa) were measured while increasing the temperature.

The value obtained by dividing the storage modulus by the loss modulus was defined as the loss tangent coefficient tanδ, and the temperature when the loss tangent coefficient tanδ was the maximum value was measured and recorded as Tmax.

In addition, the temperature at the point where the slope of the storage modulus rapidly changes was recorded as the glass transition temperature (Tg), and the storage modulus at 80 ° C was measured.

2. Evaluation of high temperature water resistance of hard coating layer

After immersing the polarizing plate laminates of Examples and Comparative Examples in water at 60° C. for 24 hours, it was observed whether color loss of the polarizer or occurrence of blisters occurred through a backlight. As a result, the polarizing plate laminates of Examples 1 and 2 did not have color loss and surface blisters (marked as O), but the polarizer laminates of Comparative Examples 1 to 3 did not lose color of the polarizer or It was confirmed that blisters occurred (marked with an X). This is shown in Figures 4 and 5.

3. Heat resistance test of hard coating layer

A polarizer crack growth inhibition test was performed by the hard coating layer. In the manufacture of the polarizing plate laminates of Examples and Comparative Examples, artificial cracks were induced in the polarizer and then left at a high temperature to observe whether the cracks grew. Specifically, in the manufacture of the polarizers of the Examples and Comparative Examples, the polarizer was scratched with a load of 100g before the retardation film was laminated on the polarizer to induce artificial cracks in the polarizer, and the rest of the manufacturing conditions were the same to prepare a polarizer laminate. .

After cutting the manufactured polarizer laminate into a width of 120 mm and a length of 100 mm, after leaving it at 80 ° C for 100 to 300 hours or more, it was observed whether cracks opened due to polarizer shrinkage and light leaked, and the number of initial total cracks (C1 ) by calculating the number of cracks (C2) through which light is leaking, the rate of occurrence of cracks in the polarizer was derived. Specifically, 200 initial cracks were generated, and the number of light leaking cracks among the initial cracks was calculated.

*Crack occurrence rate: number of light leaking cracks/number of initial total cracks x 100 (%)

As a result, the polarizing plate laminate of Example 1 had a crack generation rate of less than 3%, but the polarizing plate laminates of Comparative Examples 2 and 3 had a crack generation rate of greater than 3%. Through this, it was confirmed that the hard coating layer of the present invention has excellent heat resistance even if the thickness is thinner than that of the conventional protective film.

4. Peel force (adhesive force) test of hard coating layer

On the hard coating layer, use a cross cutter to place a cutting guide or an appropriate ruler on the sample, and draw horizontally and vertically in a grid pattern at 1 mm intervals in the shape of a banana eye. After that, after washing the surface of the protective layer with a brush or dust-free cloth, Ichiban tape (cello tape manufactured by Nichiban Co., Ltd.) was attached, and after peeling off rapidly at a peeling angle of 180 degrees, visually observed how much the hard coating layer had fallen off. do. The degree of adhesion is classified from 0B to 5B according to the cross-cut classification standard (ASTM). It can also be measured according to measurement criterion D3359-87.

5. Water permeability test of hard coating layer

The water vapor transmission rate of the hard coating layer was tested by the method described above.

6. Measurement of the photoelastic coefficient of the hard coating layer

The photoelastic coefficient of the hard coating layer was measured by the method described above.

7. Measurement of pencil hardness of hard coating layer

Pencil hardness of the hard coating layer was measured by the method described above.

Experimental example division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 One maximum value of tanδ 0.30 0.33 0.56 unmeasured unmeasured unmeasured Tmax 108℃ 141℃ 127℃ unmeasured unmeasured unmeasured E'(@80℃) 1,073 MPa 1,079℃ 2,025℃ unmeasured unmeasured unmeasured Tg 77℃ 82℃ 107℃ unmeasured unmeasured unmeasured 2 evaluation O O X X X unmeasured 3 Crack occurrence rate (%) less than 3% 20% 12% 3% 30% unmeasured 4 Peel force 5B 5B 5B unmeasured unmeasured unmeasured 5 g/m ² *day 107 unmeasured unmeasured 300 unmeasured 10 6 10 ^-12 m ² /N 10.64 unmeasured unmeasured 11 (MD direction), 12.9 (TD direction) unmeasured unmeasured 7 unit H unmeasured unmeasured 2H unmeasured B

<Effect on polarizing plate laminate structure>

The polarizing plate laminate structure of the present invention has an effect of excellent physical properties without a separate protective film by having a hard coating layer on the uppermost surface of the polarizer.

The polarizer laminate structures of Comparative Examples 2 and 3 include a thick protective film on the top surface of the laminate but have a high crack incidence rate, whereas the polarizer laminates of Examples 1 and 2 crack even if they include a thin hard coating layer. results in a low incidence.

This is because the hard coating layer has excellent adhesion to the polarizer even in a high-temperature or high-humidity environment, thereby effectively protecting the polarizer. On the other hand, since the protective films of Comparative Example 2 and Comparative Example 3 are bonded to the polarizer through an adhesive, there is a problem in that the bonding strength of the adhesive is lowered in a high temperature or high humidity environment.

On the other hand, the protective films of Comparative Example 2 and Comparative Example 3 have a high water permeability of the TAC film, so moisture permeates in a high temperature or high humidity environment, causing color loss of the polarizer, and thus the polarization degree changes in reliability at high temperature and high humidity.

<Effect on presence or absence of polysiloxane compound>

From the results of Experimental Example 1, when the hard coating layer composition includes a polysiloxane compound (Examples 1 and 2), it was confirmed that the maximum value of tanδ is kept low. The maximum value of tanδ is a factor representing chain mobility, and can be explained by a behavior in which crosslinkability decreases as the value increases and elasticity increases as the value decreases. When the composition of the hard coating layer includes a polysiloxane compound, the elasticity of the hard coating layer is increased.

In addition, when the polysiloxane compound was a cyclic polysiloxane compound (Example 1), it was confirmed that the maximum value of tanδ was lower than that when the polysiloxane compound was a linear polysiloxane compound (Example 1). This can be explained as being due to the ring structure inside the cyclic polysiloxane compound.

It was confirmed that high-temperature water resistance and heat resistance increased when the composition of the hard coating layer included the polysiloxane compound.

Claims (15)

polarizer; and
Including a hard coating layer provided on the top surface of the polarizing plate,
The maximum value of the loss tangent coefficient tanδ of the hard coating layer is 0.5 or less,
The hard coating layer is a polarizing plate laminate comprising a polysiloxane compound having a cyclic polysiloxane structure. The method of claim 1,
The maximum value of the loss tangent coefficient tanδ of the hard coating layer is a polarizing plate laminate that appears in the temperature range of 90 ℃ to 120 ℃. The method of claim 1,
A polarizing plate laminate having a thickness of the hard coating layer of 5 μm to 15 μm. The method of claim 1,
A polarizing plate laminate having a water vapor transmission rate (WVTR) of the hard coating layer of 200 g/m ² *day or less at a temperature of 38°C. The method of claim 1,
The absolute value of the photoelastic coefficient of the hard coating layer is 12 x 10 ^-12 m ² / N or less of the polarizing plate laminate. The method of claim 1,
A polarizing plate laminate in which the pencil hardness of the hard coating layer is greater than or equal to HB and less than or equal to 9H. delete delete The method of claim 1,
The content of the polysiloxane compound is 6 parts by weight or more and 50 parts by weight based on 100 parts by weight of the hard coating layer. The method of claim 1,
The hard coating layer is a polarizing plate laminate comprising a cured product of a cationic photocurable composition. The method of claim 1,
The hard coating layer is a polarizing plate laminate comprising a cured product of a photocurable composition containing an epoxy compound and an oxetane compound. The method of claim 1,
The polarizing plate laminate further comprising an adhesive layer provided on the lower surface of the polarizing plate. The method of claim 12,
The polarizing plate laminate further comprising a protective film provided between the polarizing plate and the adhesive layer. The method of claim 12,
The polarizing plate laminate further comprising a retardation film provided between the polarizing plate and the adhesive layer. an image display panel; and
An image display device comprising a polarizing plate laminate according to any one of claims 1 to 6 and 9 to 14 provided on one side or both sides of the image display panel.

Images