JP2018120119A - Optical laminate and image display device - Google Patents

Abstract

An optical layered body and an optical layered body in which traces are prevented from remaining on a polarizing plate when fixed to an adsorption table are provided. An optical laminate includes a surface protective film, a first pressure-sensitive adhesive layer, a polarizing plate, a second pressure-sensitive adhesive layer, and a release film in this order, and the tensile elasticity of the surface protective film. When the product of the rate and thickness is A, the product of the tensile modulus and thickness of the polarizing plate is B, and the product of the tensile modulus and thickness of the release film is C, A> B + C is satisfied. [Selection] Figure 1

Description

  The present invention relates to an optical laminate and an image display device.

  The polarizing plate is bonded to an optical member such as a liquid crystal cell, and is widely used for image display devices such as a liquid crystal display device. In the step of bonding the polarizing plate to an optical member such as a liquid crystal cell, for example, an optical laminate having a surface protective film, a polarizing plate and a release film in this order is fixed on an adsorption table having an adsorption pad, and the release film And the polarizing plate is bonded to the optical member.

  2. Description of the Related Art In recent years, a technique for obtaining a thin polarizing plate including a thin (for example, 12 μm or less) polarizer is known along with a demand for thinning an optical member used in an image display device. However, a thin polarizing plate is not stiff and has problems such as curling or poor bonding in a process of bonding to an optical member such as a liquid crystal cell. Patent Document 1 has a surface protective film, a thin polarizing plate, and a release film, and the ratio (T2 / T1) of the thickness (T2) of the surface protective film to the thickness (T1) of the polarizing plate is 0.8 to The polarizing plate with a surface protective film in the range of 4 is described. The polarizing plate with a surface protective film of Patent Document 1 can solve the above-described problem caused by the thinning of the polarizing plate by including the surface protective film having a thickness and stiffness.

JP, 2006-118771, A

  However, the conventional optical layered body described in Patent Document 1 and the like has a problem in that a mark of the suction pad remains on the polarizing plate when it is fixed on the suction table in the step of peeling the release film.

  The present invention has been made in order to solve the above-described conventional problems, and a main object thereof is an optical layered body in which traces remain on the polarizing plate when fixed to an adsorption table, and a polarizing plate of the optical layered body It is providing an image display apparatus provided with.

The optical layered body of the present invention includes a surface protective film, a first pressure-sensitive adhesive layer, a polarizing plate, a second pressure-sensitive adhesive layer, and a release film in this order, and the tensile elasticity of the surface protective film. A> B + C is satisfied, where A is the product of rate and thickness, B is the product of tensile modulus and thickness of the polarizing plate, and C is the product of tensile modulus and thickness of the release film. .
In one embodiment, when the trigger peel force of the surface protective film is X (N / 50 mm) and the trigger peel force of the release film is Y (N / 50 mm), Y <X is satisfied, and Preferably, XY> 0.1 is satisfied.
In one embodiment, the sum total of the thickness of the surface protection film and the thickness of the first pressure-sensitive adhesive layer is 75 μm or more, and the thickness of the release film is 38 μm or less.
In one embodiment, the polarizing plate has a polarizer and a protective layer laminated on the surface protective film side of the polarizer, and the thickness of the polarizer is 12 μm or less.
According to another aspect of the present invention, an image display device is provided. The image display device includes the polarizing plate of the optical laminate and an optical member on which the polarizing plate is bonded via the second pressure-sensitive adhesive layer.

  ADVANTAGE OF THE INVENTION According to this invention, an image display apparatus provided with the polarizing plate of an optical laminated body and the optical laminated body which suppressed that a trace remains in a polarizing plate when it fixes to an adsorption stand can be provided.

It is a schematic sectional drawing of the optical laminated body which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows a mode that a peeling film peels from an optical laminated body. It is a schematic sectional drawing which shows a mode that a surface protection film peels from an optical laminated body. It is a schematic sectional drawing of the optical laminated body which concerns on another embodiment of this invention.

  Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

A. 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminated body 100 has the surface protective film 10, the 1st adhesive layer 20, the polarizing plate 30, the 2nd adhesive layer 40, and the peeling film 50 in this order. In one embodiment, the polarizing plate 30 includes a polarizer 31 and a first protective layer 32 stacked on the surface protective film 10 side of the polarizer 31. The thickness of the polarizer 31 is typically 12 μm or less. The total of the thickness of the surface protective film 10 and the thickness of the first pressure-sensitive adhesive layer 20 is preferably 75 μm or more, and the thickness of the release film 50 is preferably 38 μm or less. FIG. 2 is a schematic cross-sectional view of an optical layered body according to another embodiment of the present invention. In this embodiment, the polarizing plate 30 includes a polarizer 31, a first protective layer 32 laminated on the surface protective film 10 side of the polarizer 31, and a second laminated on the release film 50 side of the polarizer 31. And a protective layer 33. Like the optical laminated body 101 of this embodiment, the polarizing plate 30 may have a protective layer on both sides of the polarizer 31. In the optical laminated body 100 and the optical laminated body 101, the product of the tensile elastic modulus and thickness of the surface protective film 10 is A, the product of the tensile elastic modulus and thickness of the polarizing plate 30 is B, and the tensile elasticity of the release film 50. When the product of the rate and the thickness is C, A> B + C is satisfied. Such an optical layered body can be restrained from leaving marks on the polarizing plate when it is fixed to the adsorption table. The product B of the tensile elastic modulus and thickness of the polarizing plate 30 is the product B1 of the tensile elastic modulus and thickness of the polarizer 31, the product B2 of the tensile elastic modulus and thickness of the first protective layer 32, and It is calculated by the sum of the product B3 (when the second protective layer is present) of the tensile elastic modulus and the thickness of the second protective layer 33.

  As a result of intensive studies, the inventors of the present invention are able to prevent the optical laminate as described above from leaving traces on the polarizing plate, while the release film is peeled off from the end when the peeling film is about to be peeled off. Discovered a new problem of peeling from the interface of the surface protective film. In order to solve the above-described problem, in one embodiment, the optical laminate 100 and the optical laminate 101 have the trigger peel force of the surface protective film 10 as X (N / 50 mm), and the trigger peel force of the release film 50. Is Y (N / 50 mm), preferably Y <X, and more preferably XY> 0.1. Generally, when the film is peeled from the edge at a constant peeling speed, the peeling force of the film increases according to the peeling length immediately after the start of peeling, decreases toward a peak, and remains constant after a predetermined time. Stabilize by value. In the present specification, the trigger peeling force of the film means a peak value (maximum value) of the peeling force immediately after the start of peeling, and the normal peeling force of the film means a stable peeling force after a predetermined time has elapsed from the start of peeling. Shall mean. The optical laminated body 100 (and the optical laminated body 101) peels the peeling film 50 as shown in FIG. 3, and makes the polarizing plate 30 another optical member (for example, liquid crystal cell) through the second pressure-sensitive adhesive layer 40. It can be used when bonding to. For example, when an optical laminate having a surface protective film having a high tensile elastic modulus or an optical laminate in which the trigger peel force of the release film is larger than the trigger peel force of the surface protective film, the release film 50 is peeled off from the end. In addition, as shown in FIG. 4, the surface protective film 10 and the first pressure-sensitive adhesive layer 20 are peeled off from the polarizing plate 30 without the peeling film 50 being peeled off (the peeling film 50 is first together with the polarizing plate 30. And may be peeled off. In contrast, in the optical laminate 100 according to one embodiment, the trigger peel force (Y) of the release film 50 is smaller than the trigger peel force (X) of the surface protective film 10 as described above. Thereby, as shown in FIG. 3, the release film 50 can be peeled from the second pressure-sensitive adhesive layer 40 without peeling the surface protective film 10 and the first pressure-sensitive adhesive layer 20 from the polarizing plate 30.

  The optical laminated body 100 and the optical laminated body 101 may be a single wafer or may be long.

B. Surface protective film A surface protective film is laminated | stacked on the one surface of a polarizing plate through the 1st adhesive layer, and can function as a protective film of a polarizing plate. The surface protective film is typically a transparent film having isotropic properties. The surface protective film can be peeled and removed at any appropriate time after the polarizing plate is bonded to another optical member via the second pressure-sensitive adhesive layer.

  The thickness of the surface protective film is preferably 25 μm to 250 μm, more preferably 50 μm to 200 μm, and particularly preferably 70 μm to 150 μm. By using a surface protective film having sufficient thickness and rigidity, it is possible to suppress the occurrence of curling in the step of bonding the polarizing plate to an optical member such as a liquid crystal cell, and further, to convey each layer constituting the optical laminate. However, when laminating, the transportability of the laminate can be improved, and as a result, the production efficiency of the optical laminate can be improved.

  The tensile elastic modulus of the surface protective film is preferably 2000 MPa to 5000 MPa, more preferably 2500 MPa to 4500 MPa, and particularly preferably 3000 MPa to 4000 MPa.

  Examples of the material constituting the surface protective film include polyester resins such as polyethylene terephthalate film, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, and polyolefin resins. Resin and acrylic resin are mentioned. Of these, polyester resins are preferred.

C. Polarizing plate The polarizing plate contains at least a polarizer. Preferably, the polarizing plate has a protective layer on at least one side of the polarizer.

C-1. Polarizer The thickness of the polarizer is preferably 12 μm or less, more preferably 1 μm to 10 μm, and even more preferably 3 μm to 8 μm, as described above. The tensile elastic modulus of the polarizer is preferably 300 MPa to 1000 MPa, more preferably 400 MPa to 900 MPa, and particularly preferably 500 MPa to 800 MPa.

The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. In one embodiment, the transmittance of the polarizer at a wavelength of 589 nm (also referred to as single transmittance) is preferably 42.0% to 46.0%, more preferably 44.5% to 46.0%. It is. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more. In another embodiment, the polarizer preferably has a degree of polarization P greater than − (10 ^0.929T-42.4 −1) × 100% and transmission when the transmittance T is less than 42.3%. When the rate T is 42.3% or more, the polarization degree P is 99.9% or more.

  Any appropriate polarizer can be adopted as the polarizer. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

  Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.

  The dyeing with iodine is performed, for example, by immersing a PVA film in an iodine aqueous solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing a PVA film in water and washing it with water before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.

  As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Further, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the boric acid aqueous solution. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a polarizer protective layer).

C-2. Protective layer The protective layer (the first protective layer and the second protective layer) is formed of any suitable film that can be used as a protective layer for the polarizer. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain For example, a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition. The constituent material of the first protective layer and the constituent material of the second protective layer may be the same or different from each other.

  The protective layer may be subjected to surface treatment such as hard coat treatment, antireflection treatment, antisticking treatment, and antiglare treatment as necessary.

  The thickness of the protective layer is typically 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, and still more preferably 5 μm to 150 μm. In addition, when the surface treatment is performed, the thickness of the protective layer is a thickness including the thickness of the surface treatment layer. The thickness of the first protective layer and the thickness of the second protective layer may be the same as or different from each other. The tensile elastic modulus of the protective film constituting the protective layer is preferably 1500 MPa to 3800 MPa, more preferably 2000 MPa to 3300 MPa, and particularly preferably 2300 MPa to 3000 MPa.

D. Release film The release film is laminated on the side opposite to the surface protective film of the polarizing plate via the second pressure-sensitive adhesive layer, and when the polarizing plate is bonded to another optical member via the second pressure-sensitive adhesive layer. Stripped and removed.

  The thickness of the release film is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and still more preferably 20 to 50 μm. The tensile elastic modulus of the release film is preferably 2000 MPa to 5000 MPa, more preferably 2500 MPa to 4500 MPa, and particularly preferably 3000 MPa to 4000 MPa.

  The release film is typically composed of a plastic film and a release imparting layer provided on one side of the plastic film. Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyester film such as polyethylene terephthalate film, polybutylene terephthalate film, polyurethane, etc. Examples thereof include a film and an ethylene-vinyl acetate copolymer film. Among these, a polyester film is preferable. The release imparting layer may be a layer coated with any appropriate release agent such as silicone, long chain alkyl, or fluorine.

  The release film is bonded to the polarizing plate after applying and drying the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer on the release imparting layer.

E. Adhesive layer Any appropriate adhesive can be used as the adhesive constituting the adhesive layer. Such adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives. An adhesive, a cellulose adhesive, etc. are mentioned. Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics.

  The thickness of the pressure-sensitive adhesive layer is preferably 7 μm to 30 μm, more preferably 10 μm to 25 μm. The thickness of the first pressure-sensitive adhesive layer and the thickness of the second pressure-sensitive adhesive layer may be the same or different from each other.

F. Image Display Device The optical layered body described in items A to E can be used when a polarizing plate is bonded to an optical member included in an image display device such as a liquid crystal display device and an organic EL display device. Therefore, the optical layered body of the present invention includes an image display device using the polarizing plate. The image display device of the present invention includes the polarizing plate of the optical laminate of the present invention and an optical member having the polarizing plate bonded via a second pressure-sensitive adhesive layer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the measuring method and evaluation method of each characteristic are as follows.

(1) Thickness The thickness was measured using a digital micrometer (KC-351C manufactured by Anritsu Corporation).
(2) Tensile modulus The film or polarizing plate to be measured is formed into a tensile test dumbbell having a parallel part width of 10 mm and a length of 40 mm based on JIS K6734: 2000, and a tensile test is performed in accordance with JIS K7161: 1994. Tensile modulus was determined.
(3) Normal peeling force of the surface protective film The end of the long side of the long optical laminate is 50 mm × 100 mm in size so that the long side of the optical laminate corresponds to the short side of the measurement sample. A sample for measurement was cut. The release film was peeled from the measurement sample, and the pressure-sensitive adhesive layer on the peeled surface was bonded to a flat plate-like peeling jig.
Next, the polarizing plate interface and the first pressure-sensitive adhesive layer are peeled off from the short side of the measurement sample, the surface protective film and the first pressure-sensitive adhesive layer are chucked, pulled using a tensile tester, and peel strength (N / 50 mm). (Tensile direction: 180 ° with respect to the surface of the optical laminate, tensile speed: 300 mm / min). The peel force was measured for five measurement samples, and the average value of the measured values in each measurement sample was adopted as the normal peel force of the surface protective film.
(4) Trigger peeling force of surface protective film The length of the long side of the long optical laminate is 50 mm × 100 mm so that the long side of the optical laminate corresponds to the short side of the measurement sample. A sample for measurement was cut. The release film was peeled from the measurement sample, and the pressure-sensitive adhesive layer on the peeled surface was bonded to a flat plate-like peeling jig.
Next, a 19 mm width polyester adhesive tape (manufactured by Nitto Denko Corporation, product name “No. 31B”) corresponds to the short side of the measurement sample (the long side of the optical laminate) so as not to contact the peeling jig. It was bonded to the surface protective film at the edge on the side) side, and further, a polyester base adhesive tape (manufactured by Nitto Denko Corporation, product name “No. 343B”) was bonded to the polyester adhesive tape.
Next, the polyester base adhesive tape is chucked, pulled using a tensile tester, and peel strength (N / 50 mm) is measured (tensile direction: 90 ° with respect to the surface of the optical laminate, tensile speed: 300 mm). / Min, tensile distance: 60 mm), and the peak value (maximum value) of the peel force was defined as the “trigger peel force (N / 50 mm)” of the surface protective film. The trigger peel force was measured for five measurement samples, and the average value of the measurement values in each measurement sample was adopted as the trigger peel force of the surface protective film. In the measurement of the trigger peeling force of the surface protective film, the surface protective film is peeled off with the peeling interface between the first pressure-sensitive adhesive layer and the polarizing plate (the surface protective film and the first pressure-sensitive adhesive layer are polarizing plates). Peel from).
(5) Normal peeling force of the release film The end of the long side of the long optical laminate is 50 mm × 100 mm in size so that the long side of the optical laminate corresponds to the short side of the measurement sample. A sample for measurement was cut. The measurement sample was bonded to a flat plate-shaped peeling jig with an acrylic adhesive with the surface protective film side down.
Next, the peeling film interface and the second pressure-sensitive adhesive layer were peeled off from the short side of the measurement sample, the peeling film was chucked, pulled using a tensile tester, and the peeling force (N / 50 mm) was measured (tensile) Direction: 180 ° with respect to the surface of the optical laminate, tensile speed: 300 mm / min). The peel force was measured for five measurement samples, and the average value of the measured values in each measurement sample was adopted as the normal peel force of the release film.
(6) Trigger peeling force of release film The length of the long side of the long optical laminate is 50 mm × 100 mm so that the long side of the optical laminate corresponds to the short side of the measurement sample. A sample for measurement was cut. The measurement sample was bonded to a flat plate-shaped peeling jig with an acrylic adhesive with the surface protective film side down.
Next, a 19 mm width polyester adhesive tape (manufactured by Nitto Denko Corporation, product name “No. 31B”) corresponds to the short side of the measurement sample (the long side of the optical laminate) so as not to contact the peeling jig. The polyester adhesive tape (product name “No. 343B” manufactured by Nitto Denko Corporation) was further bonded to the polyester adhesive tape.
Next, the polyester base adhesive tape is chucked, pulled using a tensile tester, and peel strength (N / 50 mm) is measured (tensile direction: 90 ° with respect to the surface of the optical laminate, tensile speed: 300 mm). / Min, tensile distance: 60 mm), and the peak value (maximum value) of the peel force was defined as the “trigger peel force (N / 50 mm)” of the peel film. The trigger peel force was measured for five measurement samples, and the average value of the measured values in each measurement sample was adopted as the trigger peel force of the release film.
(7) Peel test of peel film A long optical laminate was cut into a size of 1215 mm x 684 mm to obtain a sample for a peel test. The sample for peeling test was placed and fixed on a suction table having a suction pad with the surface protective film side facing down. Next, a peeling roll having a diameter of 20 mm was applied to the apex portion of the sample for peeling test, and the peeling film was peeled by rotating the peeling roll (peeling direction: 180 ° with respect to the surface of the optical laminate, and the measurement sample) 45 ° with respect to the long side and the short side, peeling rate: 300 mm / min).
When peeling the release film, the polarizing plate does not peel from the surface protective film, and only the release film can be peeled off, and when the peeling film is peeled off, the polarizing plate peels off from the surface protective film. It was considered as a peeling failure.
The peel film was peeled off for 10 peel test samples, and the peelability of the peel film was evaluated according to the following criteria.
A ... 90% or more of peeling test samples were successful peeling.
○: Peeling success was achieved for samples for a peel test of 60% or more and less than 90%.
Δ: Peeling was successful for samples for a peel test of 30% or more and less than 60%.
X: Peeling was successful with respect to a peel test sample of less than 30%.
Furthermore, the optical laminated body after peeling a peeling film was bonded to the liquid crystal cell through the 2nd adhesive layer using the bonding roll. Next, the surface protective film was peeled off, and the appearance of the polarizing plate was inspected. Ten samples were visually inspected and the quality of the appearance was evaluated according to the following criteria.
○ ・ ・ ・ There is no adsorption mark due to the suction pad on the polarizing plate.

<Production Example 1>
A polyethylene terephthalate film (MRF38CK manufactured by Mitsubishi Plastics, Inc.) having a thickness of about 550 μm is stretched 3.7 times in the longitudinal direction at 85 ° C., stretched 3.9 times in the transverse direction at 100 ° C., and heat-treated at 210 ° C., A biaxially stretched polyester film having a thickness of 38 μm was obtained.
On the surface of the above-mentioned biaxially stretched polyester film, a release agent comprising the release agent composition A shown below is applied and dried by a reverse gravure coating method so that the coating amount (after drying) is 0.12 g / m ^2. By doing this, a normal release film A (thickness 38 μm, tensile elastic modulus 3500 MPa) peel-treated with a silicone release agent was obtained.
(Releasing agent composition A)
A1: 24 parts by weight of a curable silicone resin (molecular weight 200000) of the general formula (I) in which the ratio of methyl group, hexenyl group and phenyl group is 100: 1: 0.1

A2: 33 parts by weight of a curable silicone resin (molecular weight 200000) of the general formula (II) in which the ratio of methyl group to vinyl group is 100: 0.2

A3: 8 parts by weight of a curable silicone resin (molecular weight 200000) of the general formula (III) in which the ratio of methyl group to hydrosilyl group is 100: 1.5

A4: 33 parts by weight of the curable silicone resin (molecular weight 200000) of the above general formula (III) in which the ratio of methyl group to hydrosilyl group is 100: 0.4 b1: unreactive silicone of the general formula (IV) 1 part by weight of resin (molecular weight 80000)

C1: 1 part by weight of MEK / toluene mixed solvent (mixing ratio is 1: 1) of addition type platinum catalyst (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.)

<Production Example 2>
A normal type release film B that has been subjected to release treatment with a silicone release agent in the same manner as in Production Example 1 except that the draw ratio of the polyethylene terephthalate film is 5.1 times in the vertical direction and 5.3 times in the horizontal direction. (Thickness 25 μm, tensile modulus 3500 MPa) was obtained.

<Production Example 3>
Except that a release agent composed of the release agent composition B shown below was used as a release agent, a release film C (thickness 38 μm) which was peeled with a silicone release agent in the same manner as in Production Example 1. , Tensile modulus of elasticity 3500 MPa).
(Releasing agent composition B)
A1: 32 parts by weight of the curable silicone resin (molecular weight 200000) of the above general formula (I) in which the ratio of methyl group, hexenyl group and phenyl group is 100: 1: 0.1 a2: methyl group and vinyl group 66 parts by weight of the curable silicone resin (molecular weight 200000) of the above general formula (II) having a ratio of 100: 0.2 is 1 to 1 of the unreactive silicone resin (molecular weight 80000) of the above general formula (IV). Part by weight · c1: 1 part by weight MEK / toluene mixed solvent (mixing ratio is 1: 1) of addition type platinum catalyst (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.)

<Production Example 4>
A heavy release type release film that was released with a silicone release agent in the same manner as in Production Example 3 except that the draw ratio of the polyethylene terephthalate film was 5.1 times in the vertical direction and 5.3 times in the horizontal direction. D (thickness 25 μm, tensile modulus 3500 MPa) was obtained.

<Production Example 5>
A light release type release film E (thickness: 38 μm) which was peeled with a silicone release agent in the same manner as in Production Example 1 except that a release agent comprising the release agent composition C shown below was used as the release agent. , Tensile modulus of elasticity 3500 MPa).
(Releasing agent composition C)
A1: 16 parts by weight of the curable silicone resin (molecular weight 200000) of the above general formula (I) in which the ratio of methyl group, hexenyl group and phenyl group is 100: 1: 0.1 a2: methyl group and vinyl group 33 parts by weight of the curable silicone resin (molecular weight 200000) of the above general formula (II) having a ratio of 100: 0.2 and the above general formula having a ratio of a3: methyl group and hydrosilyl group of 100: 1.5 16 parts by weight of curable silicone resin (molecular weight 200000) of (III) a4: curable silicone resin of general formula (III) (molecular weight 200000) in which the ratio of methyl group to hydrosilyl group is 100: 0.4 33 parts by weight · b1: 1 part by weight of the unreactive silicone resin (molecular weight 80000) of the above general formula (IV) · c1: 1 part by weight of an addition type platinum catalyst (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.) MEK / toluene mixed solvent (mixing ratio 1: 1)

<Production Example 6>
A light release type release film that has been subjected to a release treatment with a silicone release agent in the same manner as in Production Example 5 except that the draw ratio of the polyethylene terephthalate film is 5.1 times in the vertical direction and 5.3 times in the horizontal direction. F (thickness 25 μm, tensile elastic modulus 3500 MPa) was obtained.

<Example 1>
1. Preparation of Polarizing Plate A long amorphous polyethylene terephthalate (A-PET) film (manufactured by Mitsubishi Plastics, trade name “Novaclear”, thickness: 100 μm) is prepared as a base material. An aqueous solution of alcohol (PVA) resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “GOHSENOL (registered trademark) NH-26”) was applied at 60 ° C. and dried to form a PVA resin layer having a thickness of 7 μm. The laminated body thus obtained was immersed in an insolubilizing bath having a liquid temperature of 30 ° C. for 30 seconds (insolubilizing step). Subsequently, it was immersed in a dyeing bath having a liquid temperature of 30 ° C. for 60 seconds (dyeing process). Next, it was immersed in a crosslinking bath at a liquid temperature of 30 ° C. for 30 seconds (crosslinking step). Thereafter, the laminate was uniaxially stretched in the machine direction (longitudinal direction) between rolls having different peripheral speeds while being immersed in a boric acid aqueous solution having a liquid temperature of 60 ° C. The immersion time in the boric acid aqueous solution was 120 seconds, and the laminate was stretched until just before breaking. Thereafter, the laminate was immersed in a cleaning bath and then dried with warm air of 60 ° C. (cleaning / drying step). In this way, a long polarizer laminate in which a polarizer having a thickness of 5 μm was formed on the substrate was obtained.
Next, a (meth) acrylic resin film having a lactone ring structure with a thickness of 40 μm is prepared as a protective film constituting the protective layer, and the easy-adhesion treated surface of the protective film is subjected to corona treatment, so that the polarizer side of the polarizer laminate is provided. A protective layer (thickness: 40 μm, tensile elastic modulus: 2650 MPa) / polarizer (thickness: 5 μm, tensile elastic modulus) is obtained by laminating the above-mentioned protective film subjected to corona treatment on the surface and peeling the substrate from the polarizer. : 650 MPa) was obtained as a long polarizing plate.
2. Bonding of Release Film A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Furthermore, 0.1 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged with ethyl acetate to 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring. Then, the temperature of the liquid in the flask was kept at around 60 ° C., and a polymerization reaction was carried out for 7 hours. Then, ethyl acetate was added to the obtained reaction liquid, and the solution of the acrylic polymer (A-1) with a weight average molecular weight of 1.4 million adjusted to solid content concentration 30% was prepared.
0.095 part of trimethylolpropane xylylene diisocyanate (trade name: Takenate D110N, manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent with respect to 100 parts of the solid content of the resulting acrylic polymer (A-1) solution, , Dibenzoyl peroxide (trade name: Niper BMT40SV, manufactured by Nippon Oil & Fats Co., Ltd.) 0.3 parts, thiol-based silane coupling agent (C1), methyl group and mercapto group-containing alkoxysilyl resin (trade name: X- 41-1810, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.2 parts, acetoacetyl group-containing silane coupling agent (C2), acetoacetyl group-containing silane coupling agent (trade name: A-100, Soken Chemical Co., Ltd.) ) Made) Acrylic adhesive solution A was prepared by blending 0.2 parts.
Next, the acrylic pressure-sensitive adhesive solution A is uniformly applied to the surface of the release film A with a fountain coater, dried in an air circulation type thermostatic oven at 155 ° C. for 2 minutes, and the surface of the release film A has a thickness of 20 μm. An adhesive layer was formed. Next, a release film-attached polarizing plate was produced by bonding the release film A to the polarizer side of the polarizing plate via an adhesive layer.
Next, the release film is peeled off from the polarizing plate on which the release film is bonded (peeling step), and the peeled film peeled off on the polarizer side surface of the polarizing plate is bonded again (rebonding step). Then, a long polarizing plate with a release film was prepared.
3. Bonding of surface protective film In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube and a condenser, 94 parts by mass of 2-ethylhexyl acrylate (2EHA), 1 part by mass of N, N-diethylacrylamide (DEAA) Parts, ethoxydiethylene glycol acrylate (EDE) 1 part by weight, 4-hydroxybutyl acrylate (HBA) 4 parts by weight, 2,2′-azobisisobutyronitrile 0.2 part by weight as a polymerization initiator, ethyl acetate 150 parts by weight , And nitrogen gas was introduced while gently stirring, and the polymerization temperature was kept at around 60 ° C. for 5 hours to prepare a solution of acrylic polymer (A-2) (40% by mass). did. The weight average molecular weight of the acrylic polymer (A-2) was 570,000, and the glass transition temperature (Tg) was −68 ° C.
The acrylic polymer (A-2) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and isocyanurate of hexamethylene diisocyanate (Nippon Polyurethane Industry Co., Ltd.) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. Co., Ltd., Coronate HX: C / HX) 2 parts by mass (solid content 2 parts by mass) and 2 parts by mass of dibutyltin dilaurate (1% by mass ethyl acetate solution) (solid content 0.02 parts by mass) as a crosslinking catalyst were added. Then, mixing and stirring were performed to prepare an acrylic pressure-sensitive adhesive solution B.
A transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 75 μm was prepared as a surface protective film. The acrylic adhesive solution B was applied to the PET film and heated at 130 ° C. for 1 minute to form an adhesive layer having a thickness of 15 μm. Next, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a separator with a silicone treatment on one side, was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet (surface protective film with a separator).
The separator is peeled from the pressure-sensitive adhesive sheet, and the surface protective film (thickness: 75 μm, tensile elastic modulus: 3500 MPa) is bonded to the surface of the polarizing plate with the release film opposite to the release film, thereby forming a long shape. An optical laminate 1 was prepared. The optical laminate 1 has a layer structure of surface protective film / first pressure-sensitive adhesive layer / polarizing plate / second pressure-sensitive adhesive layer / release film.
The obtained optical laminated body 1 was used for evaluation of peeling force and a peeling test. Moreover, the stiffness index (X) represented by the following formula (1) was calculated. The results are shown in Tables 1 and 2.
X = A-B-C (1)
A: Tensile modulus (MPa) of surface protective film × Thickness (μm) of surface protective film
B: Tensile elastic modulus (MPa) of polarizing plate × Thickness of polarizing plate (μm)
C: Tensile elastic modulus (MPa) of release film x thickness of release film (μm)
In addition, when a polarizing plate has a 1st protective layer and a 2nd protective layer, the value of B in said Formula (1) shall be calculated based on the following formula | equation (2).
B = B1 + B2 + B3 (2)
B1: Tensile elastic modulus (MPa) of polarizer × Thickness of polarizer (μm)
B2: Tensile elastic modulus (MPa) of the first protective layer × Thickness of the first protective layer (μm)
B3: Tensile elastic modulus (MPa) of the second protective layer × thickness (μm) of the second protective layer

<Example 2>
A long optical laminate 2 was produced in the same manner as in Example 1 except that the release film B was used as the release film. The optical laminate 2 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 3>
A long optical laminate 3 was produced in the same manner as in Example 1 except that the release film C was used as the release film. The optical laminate 3 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 4>
A long optical laminate 4 was produced in the same manner as in Example 1 except that the release film D was used as the release film. The optical laminate 4 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 5>
Except that the release film E was used as the release film and that the peeling step and the re-bonding step were not performed when the long polarizing plate with the release film was prepared, the length was the same as in Example 1. The optical laminated body 5 was produced. The optical laminate 5 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 6>
Except that the release film F was used as the release film and the peeling step and the re-bonding step were not performed when the long polarizing plate with the release film was produced, the length was the same as in Example 1. The optical laminated body 6 was produced. The optical laminate 6 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 7>
A long optical laminate 7 was produced in the same manner as in Example 1 except that the release film E was used as the release film. The optical laminate 7 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 8>
A long optical laminate 8 was produced in the same manner as in Example 1 except that the release film F was used as the release film. The optical laminate 8 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 9>
A long optical laminate 9 was prepared in the same manner as in Example 1 except that the peeling step and the rebonding step were not performed when the long polarizing plate with a release film was prepared. The optical laminate 9 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 10>
A long optical laminate 10 was prepared in the same manner as in Example 2 except that the peeling step and the re-bonding step were not performed when the long polarizing plate with a release film was prepared. The optical laminate 10 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 11>
A long optical laminate 11 was prepared in the same manner as in Example 3 except that the peeling step and the re-bonding step were not performed when the long polarizing plate with a release film was prepared. The optical laminate 11 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 12>
A long optical laminate 12 was prepared in the same manner as in Example 4 except that the peeling step and the rebonding step were not performed when the long polarizing plate with a release film was prepared. The optical laminate 12 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 13>
Using a (meth) acrylic resin film having a lactone ring structure with a thickness of 20 μm as a protective film constituting the protective layer (first protective layer), subjecting the easy-adhesion treated surface of the protective film to corona treatment, The protective film subjected to corona treatment was bonded to the surface of the polarizer, and the substrate was peeled from the polarizer. Subsequently, a (meth) acrylic resin film having a lactone ring structure having a thickness of 20 μm is used as a protective film constituting the protective layer (second protective layer), and the easy-adhesion treated surface of the protective film is subjected to corona treatment, whereby a polarizer A first protective layer (thickness: 20 μm, tensile elastic modulus: 2650 MPa) / polarizer (thickness: 5 μm, tensile elastic modulus: 650 MPa) / A polarizing plate having a layer structure of a second protective layer (thickness: 20 μm, tensile elastic modulus: 2650 MPa) was obtained.
A long optical laminate 13 was produced in the same manner as in Example 1 except that the polarizing plate was used. The optical laminate 13 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 14>
The use of a (meth) acrylic resin film having a lactone ring structure with a thickness of 25 μm as the protective film constituting the protective layer (first protective layer), and the protective film constituting the protective layer (second protective layer) A long optical laminate 14 was produced in the same manner as in Example 13 except that a (meth) acrylic resin film having a lactone ring structure having a thickness of 13 μm was used. The optical laminate 14 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 15>
Using a (meth) acrylic resin film having a lactone ring structure with a thickness of 20 μm as a protective film constituting the protective layer (first protective layer), subjecting the easy-adhesion treated surface of the protective film to corona treatment, The protective film subjected to corona treatment was bonded to the surface of the polarizer, and the substrate was peeled from the polarizer. Subsequently, a (meth) acrylic resin film having a lactone ring structure having a thickness of 20 μm is used as a protective film constituting the protective layer (second protective layer), and the easy-adhesion treated surface of the protective film is subjected to corona treatment, whereby a polarizer A first protective layer (thickness: 20 μm, tensile elastic modulus: 2650 MPa) / polarizer (thickness: 5 μm, tensile elastic modulus: 650 MPa) / A polarizing plate having a layer structure of a second protective layer (thickness: 20 μm, tensile elastic modulus: 2650 MPa) was obtained.
A long optical laminate 15 was produced in the same manner as in Example 9 except that the polarizing plate was used. The optical laminate 15 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Example 16>
The use of a (meth) acrylic resin film having a lactone ring structure with a thickness of 25 μm as the protective film constituting the protective layer (first protective layer), and the protective film constituting the protective layer (second protective layer) A long optical laminate 16 was prepared in the same manner as in Example 15 except that a (meth) acrylic resin film having a lactone ring structure having a thickness of 13 μm was used. The optical laminate 16 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Comparative Example 1>
A long optical laminate 17 was produced in the same manner as in Example 5 except that a polyethylene terephthalate (PET) film (thickness: 38 μm, tensile elastic modulus: 3500 MPa) was used as the surface protective film. The optical laminate 17 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Comparative example 2>
A long optical laminate 18 was produced in the same manner as in Example 5 except that a polyethylene terephthalate (PET) film (thickness: 50 μm, tensile modulus: 3500 MPa) was used as the surface protective film. The optical laminate 18 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Comparative Example 3>
A long optical laminate 19 was produced in the same manner as in Example 9 except that a polyethylene terephthalate (PET) film (thickness: 38 μm, tensile elastic modulus: 3500 MPa) was used as the surface protective film. The optical laminate 19 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Comparative example 4>
A long optical laminate 20 was produced in the same manner as in Example 9 except that a polyethylene terephthalate (PET) film (thickness: 50 μm, tensile modulus: 3500 MPa) was used as the surface protective film. The optical laminate 20 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Comparative Example 5>
A long optical laminate 21 was produced in the same manner as in Example 11 except that a polyethylene terephthalate (PET) film (thickness: 38 μm, tensile elastic modulus: 3500 MPa) was used as the surface protective film. The optical laminate 21 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

<Comparative Example 6>
A long optical laminate 22 was produced in the same manner as in Example 11 except that a polyethylene terephthalate (PET) film (thickness: 50 μm, tensile elastic modulus: 3500 MPa) was used as the surface protective film. The optical laminate 22 was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

  As is clear from Tables 1 and 2, the optical laminates of Examples 1 to 16 having a positive stiffness index did not leave any adsorption marks on the polarizing plate. The optical laminate of the example in which the trigger peel force (Y) of the release film is smaller than the trigger peel force (X) of the surface protective film is high in the peelability of the release film and XY is greater than 0.1. The optical laminate has particularly high peelability of the release film.

  The optical layered body of the present invention is suitably used for image display devices such as liquid crystal display devices and organic EL display devices.

DESCRIPTION OF SYMBOLS 10 Surface protective film 20 1st adhesive layer 30 Polarizing plate 31 Polarizer 32 1st protective layer 33 2nd protective layer 40 2nd adhesive layer 50 Release film 100 Optical laminated body 101 Optical laminated body

Claims (6)

It has a surface protective film, a first pressure-sensitive adhesive layer, a polarizing plate, a second pressure-sensitive adhesive layer, and a release film in this order,
When the product of the tensile modulus and thickness of the surface protective film is A, the product of the tensile modulus and thickness of the polarizing plate is B, and the product of the tensile modulus and thickness of the release film is C ,
A> B + C
An optical laminate that satisfies the requirements. When the trigger peel force of the surface protective film is X (N / 50 mm) and the trigger peel force of the release film is Y (N / 50 mm),
Y <X
The optical laminate according to claim 1, wherein XY> 0.1
The optical laminate according to claim 2, wherein the optical laminate is satisfied. The sum of the thickness of the surface protective film and the thickness of the first pressure-sensitive adhesive layer is 75 μm or more,
The optical laminated body in any one of Claims 1-3 whose thickness of the said peeling film is 38 micrometers or less. The polarizing plate has a polarizer and a protective layer laminated on the surface protective film side of the polarizer,
The optical laminated body in any one of Claims 1-4 whose thickness of the said polarizer is 12 micrometers or less. An image display device comprising: the polarizing plate of the optical laminate according to claim 1; and an optical member on which the polarizing plate is bonded via the second pressure-sensitive adhesive layer.