Polarizing laminate and optical lens

Abstract

Provided is a polarizing laminate in which a first protective layer and a second protective layer are laminated onto the two surfaces of a polarizing layer with an adhesive layer therebetween, the polarizing laminate being characterized in that: if the peel strength of the polarizing laminate is measured under conditions in which the tensile speed is 100 mm / min, then the peel strength is 2.0-30.0 N / 10 mm; and the absolute value of the difference between the peel strength between the polarizing layer and the first protective layer and the peel strength between the polarizing layer and the second protective layer is 0.2-8.0 N / 10 mm.

Description

Polarizing laminate and optical lens

[0001] The present disclosure relates to a polarizing laminate and an optical lens.

[0002] Optical lenses are used as anti-glare glasses, sunglasses, goggles, corrective glasses, etc. for outdoor activities such as mountain climbing, fishing, and baseball, as well as for driving vehicles, with the aim of blocking light reflected from road surfaces, wall surfaces, snow surfaces, water surfaces, etc. These optical lenses have a laminated structure in which a lens body and a polarizing layer are laminated via an adhesive layer, and a protective layer is usually laminated on the surface of the polarizing layer.

[0003] Patent Document 1 discloses a polarizing laminate that can efficiently impart excellent properties despite its simple structure, the polarizing laminate being composed of a polarizing sheet layer in which protective layers are laminated on both sides of the polarizing layer via an adhesive, the adhesive being composed of an adhesive having an isocyanate group or a urethane group, and the protective layers being composed of a polyamide resin. Patent Document 1 also discloses a lens composed of a polarizing laminate that is composed of a polarizing sheet layer in which protective layers are laminated on both sides of the polarizing layer and a thermoformable resin layer thermally bonded to at least one of the protective layers, the thermoformable resin layer being composed of a polyamide resin.

[0004] Patent document 2 discloses a functional lens in which a lens body, an adhesive layer, and an optical function layer are laminated directly or indirectly in this order, and which is intended to be mounted in a mounting groove of a frame part, and in which the end face facing the mounting groove is formed in a shape such that the apex is located on the mounting side of the adhesive layer in the thickness direction.

[0005] Patent Document 1: JP 2006-227591 A, International Publication No. 2016 / 158680

[0006] In recent years, there has been a demand for product development that takes into account the Sustainable Development Goals (SDGs). From the perspective of the SDGs, product recyclability is one of the important characteristics. However, Patent Documents 1 and 2 do not consider the recyclability of lenses at all. For example, Patent Document 1 uses a polyamide resin as the thermoformable resin layer, and the polarizing laminate includes an adhesive having an isocyanate group or a urethane group, and a polarizing layer. Therefore, when recycling the thermoformable resin layer in the lens, it is necessary to remove only the thermoformable resin layer from the lens. However, the thermoformable resin layer and the polarizing laminate are usually firmly bonded together from the perspective of durability. Therefore, the present inventors have realized that it is not easy to remove only the thermoformable resin layer from the lens.

[0007] An object of the present disclosure is to provide an optical lens that is both recyclable and durable, and to provide a polarizing laminate that can provide such an optical lens.

[0008] The present disclosure relates to the following: [1] A polarizing laminate including a first protective layer and a second protective layer laminated on both sides of a polarizing layer via an adhesive layer, wherein the peel strength of the polarizing laminate measured at a tensile speed of 100 mm / min is 2.0 to 30.0 N / 10 mm, and the absolute value of the difference between the peel strength between the polarizing layer and the first protective layer and the peel strength between the polarizing layer and the second protective layer is 0.2 to 8.0 N / 10 mm. [2] The polarizing laminate according to [1], wherein the adhesive layer is a layer containing a cured product of a urethane adhesive. [3] The polarizing laminate according to [1] or [2], wherein the adhesive layer has a thickness of 1.0 to 100.0 μm. [4] The polarizing laminate according to any one of [1] to [3], wherein at least one layer selected from the group consisting of the first protective layer and the second protective layer contains a polyamide resin. [5] The polarizing laminate according to [4], wherein the polyamide resin has a structure represented by the following formula (4): (In formula (4), R １ and R ２ each independently represents an alkyl group having 1 to 4 carbon atoms; X ３represents an alkylene group having 1 to 6 carbon atoms, n represents an integer of 1 or more, and p and q each independently represent an integer of 0 to 4. [6] The polarizing laminate according to any one of [1] to [5], wherein at least one layer selected from the group consisting of the first protective layer and the second protective layer has a retardation value of 300 nm or more. [7] The polarizing laminate according to any one of [1] to [6], wherein the polarizing layer contains polyvinyl alcohol. [8] An optical lens comprising the polarizing laminate according to any one of [1] to [7] and a base layer. [9] The optical lens according to [8], wherein the base layer is on a surface of the polarizing laminate.

[10] The optical lens according to [9], wherein the base layer contains a polyamide resin having a structure represented by the following formula (4): (In formula (4), R １ and R ２ each independently represents an alkyl group having 1 to 4 carbon atoms; X ３ represents an alkylene group having 1 to 6 carbon atoms, n represents an integer of 1 or more, and p and q each independently represent an integer of 0 to 4.

[0009] According to the present disclosure, it is possible to provide an optical lens that is both recyclable and durable, and a polarizing laminate that provides the optical lens.

[0010] 1A and 1B are cross-sectional views of a polarizing laminate according to one embodiment of the present disclosure, and an optical lens according to one embodiment of the present disclosure.

[0011] The present disclosure will be described below based on specific embodiments. In this specification, when a numerical range is described with a lower limit and an upper limit separately, the numerical range can be a combination of any lower limit and any upper limit. In this disclosure, a numerical range expressed using "A to B" means a numerical range that includes the lower and upper limits, which are the endpoints.

[0012] <Polarizing Laminate> The polarizing laminate of the present disclosure is a polarizing laminate in which a first protective layer and a second protective layer are laminated on both sides of a polarizing layer via an adhesive layer, and the peel strength of the polarizing laminate measured at a tensile speed of 100 mm / min (hereinafter simply referred to as the peel strength of the polarizing laminate) is 2.0 to 30.0 N / 10 mm. Specifically, a 10 mm wide test piece is prepared from the polarizing laminate, and the peel strength between the polarizing layer and the first protective layer is measured at a tensile speed of 100 mm / min according to JIS K6854 T-peel test method. The peel strength between the polarizing layer and the second protective layer is measured at a tensile speed of 100 mm / min. The smaller of the first peel strength and the second peel strength is defined as the peel strength of the polarizing laminate. Setting the pulling speed to 100 mm / min makes it easy to reproduce a situation similar to the peel behavior observed when wearing a lens, and the strength of the peel strength is emphasized, making it easier to understand the stability of the adhesive behavior. The peel strength of the polarizing laminate is the peel strength in the layer thickness direction. If the peel strength of the polarizing laminate is less than 2.0 N / 10 mm, the strength of the polarizing laminate portion in an optical lens containing the polarizing laminate will be insufficient, resulting in a lens with poor durability. If the peel strength of the polarizing laminate exceeds 30.0 N / 10 mm, the strength of the polarizing laminate portion will be too high, resulting in a lens with poor recyclability. The peel strength of the polarizing laminate is preferably 5.0 to 25.0 N / 10 mm, and more preferably 8.0 to 20.0 N / 10 mm. The peel strength of the polarizing laminate can be adjusted by changing the amount and type of material used in the adhesive layer, or by changing the thickness of the adhesive layer. For example, if multiple materials are used in the adhesive layer, the peel strength can be adjusted by changing the blending ratio of the respective materials. The method for measuring the peel strength of the polarizing laminate will be described later.

[0013] Furthermore, in the polarizing laminate of the present disclosure, the absolute value of the difference between the peel strength (first peel strength) between the polarizing layer and the first protective layer and the peel strength (second peel strength) between the polarizing layer and the second protective layer is 0.2 to 8.0 N / 10 mm. If the absolute value of the difference between the first peel strength and the second peel strength is less than 0.2 N / 10 mm, when peeling the layers to recycle the polarizing sheet or polarized lens, the peel interface may be unstable, causing some of the polarizing layer material to adhere to the first protective layer or the second protective layer. In other words, the peelability is reduced, making it difficult to recover the protective layer. On the other hand, if the absolute value of the difference between the first peel strength and the second peel strength is more than 8.0 N / 10 mm, the peel position at the interface between the first protective layer and the polarizing layer, or the peel position at the interface between the second protective layer and the polarizing layer, cannot be controlled, and peeling can only occur from an interface with low peel strength. In other words, the peelability is reduced. The absolute value of the difference between the first peel strength and the second peel strength is preferably 0.5 to 8.0 N / 10 mm, more preferably 1.0 to 8.0 N / 10 mm, and may also be 2.0 to 7.0 N / 10 mm, or 3.0 to 7.0 N / 10 mm.

[0014] The absolute value of the difference between the first peel strength and the second peel strength can be changed by changing the type and thickness of the adhesive layer used at the interface between each protective layer and the polarizing layer, by performing corona treatment or plasma treatment on the surface of the protective layer facing the adhesive layer, and by changing the irradiation intensity of the corona treatment or plasma treatment. Corona treatment or plasma treatment increases the number of active groups that contribute to chemical reactions at the surface of the protective layer, thereby facilitating stronger adhesion between the protective layer and the adhesive layer and increasing the peel strength. The surface tension value is used as an indicator of the activation level of the protective layer. Specifically, increasing the irradiation intensity when treating the protective layer increases the activation level and the surface tension. As a result, the peel strength increases. On the other hand, decreasing the irradiation intensity reduces the improvement in surface tension and therefore the improvement in peel strength. The surface tension value of the surface of the protective layer facing the adhesive layer is preferably 35 dyne or more. There is no particular upper limit to the surface tension value, but the surface tension value may be 35 to 70 dyne. By reducing the difference in the surface tension between the first protective layer and the second protective layer through corona treatment or plasma treatment, the absolute value of the difference between the first peel strength and the second peel strength tends to be small. Of the surfaces of one or more protective layers selected from the group consisting of the first protective layer and the second protective layer, the surface facing the adhesive layer is preferably corona treated. It is also preferable that, of the surfaces of one of the first and second protective layers, the surface facing the adhesive layer is corona treated, and the surface of the other protective layer facing the adhesive layer is not corona treated. It is also effective not to simultaneously bond the first protective layer and the second protective layer to the polarizing layer. Specifically, in the first step, the first protective layer and the polarizing layer are bonded together using an adhesive layer, and then, in the second step, the second protective layer and the laminate produced in the first step are bonded together using an adhesive layer. In the second step, the second protective layer is bonded to the polarizing layer side of the laminate produced in the first step via the adhesive layer to produce the desired polarizing laminate. In this case, the absolute value of the difference between the first peel strength and the second peel strength can be increased by performing a step of winding up the laminate produced in the first step into a roll between the first step and the second step.This is thought to be because stress is generated inside the adhesive layer when the laminate is wound into a roll, and this stress reduces the adhesive strength.

[0015] As described above, the polarizing laminate (100) has a first protective layer and a second protective layer (101, 102) laminated on both sides of a polarizing layer (105) via adhesive layers (103, 104) ( FIG. 1 ). The polarizing laminate may also have other layers. That is, the polarizing laminate may have a polarizing layer 105, a first adhesive layer 103 provided on the first surface of the polarizing layer, a second adhesive layer 104 provided on the second surface of the polarizing layer, a first protective layer 101 provided on the side opposite the polarizing layer from the first adhesive layer, and a second protective layer 102 provided on the side opposite the polarizing layer from the second adhesive layer. Each layer that may constitute the polarizing laminate will be described below.

[0016] (Polarizing Layer) The polarizing layer is a layer containing a material having polarizing properties. The polarizing layer is not particularly limited, but for example, a stretched film containing a dichroic compound such as iodine or a dichroic dye, and a polarizing resin such as polyvinyl alcohol can be used. The stretched film can be prepared, for example, by subjecting a polyvinyl alcohol film obtained by stretching polyvinyl alcohol to dyeing with a dichroic compound, crosslinking, stretching (uniaxial stretching at a magnification of about 3 to 7 times), and other treatments. That is, the polarizing layer may contain a polarizing resin and may further contain a dichroic compound. The polarizing layer preferably contains polyvinyl alcohol, and more preferably further contains iodine.

[0017] The polyvinyl alcohol is not particularly limited, but examples thereof include saponified vinyl acetate polymers, saponified copolymers of vinyl acetate and copolymerizable monomers other than vinyl acetate (e.g., unsaturated carboxylic acids, unsaturated sulfonic acids, cationic monomers, etc.), and derivatives of these saponified products (e.g., formals, acetals, etc.). Derivatives include polyvinyl acetal and polyvinyl butyral. The number-average polymerization degree of polyvinyl alcohol is not particularly limited, but examples include 1,000 to 10,000 and 3,000 to 5,000. The saponification degree of polyvinyl alcohol is also not particularly limited, but is preferably 85 mol% or more, more preferably 90 mol% or more (e.g., 90 to 100 mol%), and even more preferably 95 mol% or more. Preferred examples include 90 to 100 mol%, 95 to 100 mol%, and 98 to 100 mol%.

[0018] The thickness of the polarizing layer is not particularly limited, but may be, for example, 5.0 to 100.0 μm, preferably 10.0 to 80.0 μm, and more preferably 20.0 to 60.0 μm.

[0019] (Protective Layer) The protective layers (first protective layer and second protective layer) are layers that protect the polarizing layer. The protective layer is not particularly limited as long as it can protect the polarizing layer, and examples thereof include a resin layer. The resin layer may contain one or more selected from the group consisting of thermoplastic resins and thermosetting resins, preferably a thermoplastic resin, and more preferably a thermoplastic resin. Examples of thermoplastic resins include acetyl cellulose resins such as triacetyl cellulose, polycarbonate resins, polyamide resins, polyester resins, olefin resins, acrylic resins, and urethane resins. Among these, polyamide resins are preferred. Examples of polyamide resins are not particularly limited, and examples include aliphatic polyamide resins and aromatic polyamide resins. The aliphatic polyamide resin may have a linear structure, a branched structure, or a cyclic structure. Among these, the aliphatic polyamide resin preferably has a cyclic structure. That is, the polyamide resin is preferably an alicyclic polyamide resin. The alicyclic polyamide resin has excellent transparency. Alicyclic polyamide resins are available as, for example, Trogamid (manufactured by Polypla-Evonik) and Grilamid (manufactured by EMS). The resin layer may contain one or more of these resins. Furthermore, the protective layers (first protective layer and second protective layer) may contain the same material or different materials. That is, one or more selected from the group consisting of the first protective layer and the second protective layer may contain the above-mentioned material.

[0020] The alicyclic polyamide resin can be obtained by combining suitable components selected from the group consisting of alicyclic diamines and alicyclic dicarboxylic acids, aliphatic diamines other than alicyclic diamines, aliphatic dicarboxylic acids other than alicyclic dicarboxylic acids, etc., and polymerizing them using a known method. Examples of alicyclic diamines include compounds represented by the following formula (1): (In formula (1), A １ and A ２ each independently represents a cycloalkylene group having 5 to 10 carbon atoms (preferably 6 to 8, more preferably 6), and X １represents an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4, more preferably 1 to 3).

[0021] The alicyclic dicarboxylic acid may, for example, be a compound represented by the following formula (2). (In formula (2), A ３ and A ４ each independently represents a cycloalkylene group having 5 to 10 carbon atoms (preferably 6 to 8, more preferably 6), and X ２ represents an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4, more preferably 1 to 3).

[0022] When an alicyclic diamine is used, it is preferable to use an aliphatic dicarboxylic acid other than an alicyclic dicarboxylic acid (hereinafter also referred to as aliphatic dicarboxylic acid A). Examples of the aliphatic dicarboxylic acid A include compounds represented by the following formula (3). (In formula (3), m is an integer of 1 or more, preferably 4 to 18, more preferably 6 to 16, and even more preferably 8 to 14.)

[0023] The alicyclic polyamide resin preferably has a structure represented by the following formula (4). (In formula (4), R １ and R ２ each independently represents an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2), and X ３ represents an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4, more preferably 1 to 3), n represents an integer of 1 or more (preferably 4 to 18, more preferably 6 to 16, even more preferably 8 to 14), and p and q each independently represent an integer of 0 to 4 (preferably 0 to 3, more preferably 0 to 2, even more preferably 0 to 1).

[0024] The number average molecular weight of the polyamide resin is not particularly limited, but is, for example, 0.6 × 10 ４ ~3.0 x 10 ５ may be 0.6×10 ４ ~2.0 x 10 ５ It is preferable that the ４ ~1.5 x 10 ５ More preferably, it is 2.0 × 10 ４~1.0 x 10 ５ The number average molecular weight of the polyamide resin can be measured by gel permeation chromatography (GPC) and can be calculated in terms of polystyrene.

[0025] The thickness of the protective layer is not particularly limited, but may be, for example, 20.0 to 2000.0 μm, preferably 50.0 to 800.0 μm, more preferably 80.0 to 600.0 μm, and even more preferably 100.0 to 500.0 μm. The thicknesses of the protective layers (first protective layer and second protective layer) may be the same or different.

[0026] The retardation value of the protective layer is not particularly limited, but it is preferable that one or more selected from the group consisting of the first protective layer and the second protective layer have a retardation value of 300 nm or more, and in particular, it is preferable that the retardation value of the first protective layer be 300 nm or more. By setting the retardation value of the first protective layer to 300 nm or more, the generation of white spots in the protective layer can be suppressed. The retardation value is preferably 300 to 20,000 nm, more preferably 350 to 15,000 nm, even more preferably 400 to 10,000 nm, even more preferably 450 to 7,000 nm, particularly preferably 500 to 3,000 nm, and especially preferably 550 to 2,000 nm. When the protective layer is formed by stretching, the retardation value is defined as Δn·d, where Δn is the difference in refractive index between the stretching direction and the refractive index in the direction perpendicular thereto, and d is the thickness of the protective layer. The retardation value can be controlled by the stretching ratio when producing the protective layer and the thickness of the protective layer. The retardation values ​​of the protective layers (first protective layer and second protective layer) may be the same or different.

[0027] (Adhesive Layer) The adhesive layer is not particularly limited as long as it can bond the protective layer and the polarizing layer, but is preferably a layer containing a cured adhesive. The adhesive may be a solution-based adhesive or a hot-melt adhesive. The method for curing the adhesive is not particularly limited, and known methods can be used. For example, in the case of a solution-based adhesive, the cured adhesive can be obtained by volatilizing the solvent contained in the adhesive solution. In the case of a two-component curing adhesive, the cured adhesive can be obtained by mixing a solution containing a base agent and a solution containing a curing agent. In the case of a hot-melt adhesive, the cured adhesive can be obtained by cooling and solidifying the molten adhesive. Examples of adhesives include vinyl acetate adhesives, acrylic adhesives, polyester adhesives, urethane adhesives, and epoxy adhesives. Among these, urethane adhesives are preferred. Urethane adhesives refer to adhesives containing polyurethane resins or adhesives containing an isocyanate component and a diol component. That is, the urethane adhesive may be a one-component adhesive containing polyurethane resin, or a two-component curing adhesive (i.e., a reactive curing adhesive) containing an isocyanate component and a diol component. As the isocyanate component and the diol component, a urethane prepolymer obtained by reacting an isocyanate component and a diol component can also be used.

[0028] The adhesive layer may contain one or more of these materials. The adhesive layers (first adhesive layer and second adhesive layer) may contain the same material or different materials. When the adhesive layer contains two or more materials, the blending ratio of the respective materials is not particularly limited. For example, when the urethane adhesive used in the adhesive contains a polyol component such as TM-593 (manufactured by Toyo-Morton) and an isocyanate component such as CAT-RT85 (manufactured by Toyo-Morton), the content of the isocyanate component is preferably 5 to 18 parts by mass, and more preferably 10 to 18 parts by mass, per 100 parts by mass of the polyol component contained in the adhesive. By setting the content within the above range, it becomes easier to adjust the peel strength of the polarizing laminate to the above range.

[0029] A vinyl acetate adhesive refers to an adhesive containing a vinyl acetate resin, an acrylic adhesive refers to an adhesive containing an acrylic resin, a polyester adhesive refers to an adhesive containing a polyester resin, and an epoxy adhesive refers to an adhesive containing an epoxy resin and a curing agent.

[0030] The thickness of the adhesive layer is not particularly limited, but may be, for example, 0.1 to 200.0 μm, preferably 1.0 to 100 μm, more preferably 1.5 to 80.0 μm, even more preferably 2.0 to 50.0 μm, even more preferably 3.0 to 25.0 μm, particularly preferably 5.0 to 20.0 μm, and especially preferably 5.0 to 15.0 μm. By setting the thickness of the adhesive layer within the above range, it becomes easier to adjust the peel strength of the polarizing laminate to within the above range. The thicknesses of the adhesive layers (first adhesive layer and second adhesive layer) may be the same or different.

[0031] The shape of the polarizing laminate is not particularly limited, and may be flat or curved. The method for forming the polarizing laminate into a curved shape is not particularly limited, and examples thereof include a method in which a flat polarizing laminate is formed and then subjected to bending processing. When the polarizing laminate has a curved shape, it may be more difficult to achieve both recyclability and durability. However, even in such cases, the polarizing laminate of the present disclosure can provide an optical lens that achieves both recyclability and durability.

[0032] <Optical Lens> The optical lens of the present disclosure includes the polarizing laminate of the present disclosure and a substrate layer. While the material used for the substrate layer is not particularly limited, it is preferable that the substrate layer contains a resin, and more preferably a polyamide resin. That is, it is more preferable that the substrate layer is a polyamide resin layer. By including a polyamide resin, an optical lens having high lightness, toughness, and chemical resistance can be formed. The resin may be a resin described in the protective layer section, and the polyamide resin may be a polyamide resin described in the protective layer section. The substrate layer may contain various additives, such as stabilizers (heat stabilizers, ultraviolet absorbers, antioxidants, etc.), plasticizers, lubricants, colorants, flame retardants, antistatic agents, etc.

[0033] The thickness of the substrate layer is not particularly limited, but may be, for example, 1 to 20 mm, preferably 1.2 to 10 mm, more preferably 1.4 to 8 mm, and even more preferably 1.5 to 5 mm.

[0034] The optical lens 200 preferably includes a substrate layer 201 on the surface of the polarizing laminate ( FIG. 2 ). FIG. 2 illustrates an embodiment in which the optical lens includes the substrate layer 201 on the surface of the second protective layer 102. That is, in FIG. 2 , the substrate layer 201 is provided on the surface of the second protective layer 102 opposite the side on which the polarizing layer 105 is located. The optical lens may also include a substrate layer on the surface of the first protective layer 101. That is, the substrate layer 201 may be provided on the surface of the first protective layer 101 opposite the side on which the polarizing layer 105 is located. This configuration makes it easier to control the adhesive strength between the polarizing laminate and the substrate layer, making it easier to achieve both recyclability and durability. In this configuration, the protective layer (first protective layer or second protective layer) can be used to bond to the substrate layer. The method for incorporating a base layer into the surface of the polarizing laminate is not particularly limited, but an example is a method in which a resin is injection molded onto the polarizing laminate and the polarizing laminate and the base layer are bonded by thermal welding.

[0035] The optical lens may have other layers, such as a hard coat layer, an anti-reflection layer, an anti-fogging layer, etc. The locations of these layers are not particularly limited as long as they can perform their functions, but they are preferably included on the surface of the optical lens.

[0036] The shape of the optical lens is not particularly limited, and may be flat or curved. Specifically, it may be a concave lens, a convex lens, or a concave-convex lens. The shape of the optical lens can be adjusted by a known method, for example, by injection molding a polyamide resin onto a curved polarizing laminate.

[0037] The methods for measuring and evaluating the physical properties of the polarizing laminate and the optical lens will be described below.

[0038] <Method for Measuring Peel Strength of Polarizing Laminate> The peel strength of the polarizing laminate is measured in accordance with JIS K6854 T-peel test method by preparing a 10 mm wide test piece from the polarizing laminate and performing a peel test on the test piece using an Autograph AG-X Plus manufactured by Shimadzu Corporation at a tensile speed of 100 mm / min. Specifically, the peel strengths are measured at two locations on both sides of the polarizing layer of the polarizing laminate, namely, the peel strength between the first protective layer and the polarizing layer (first peel strength) and the peel strength between the second protective layer and the polarizing layer (second peel strength), and the smaller of the first peel strength and the second peel strength is defined as the peel strength of the polarizing laminate. First, the polarizing laminate is punched out using a Thomson blade to prepare a test piece 10 mm wide and 200 mm long. When measuring the first peel strength, an incision is made in the first protective layer of the obtained test piece using a cutter or the like, and the polarizing laminate is curved so that the incised portion faces outward, thereby creating a peel initiation interface between the first protective layer and the polarizing layer. The side containing the first protective layer is then clamped between the upper chuck of the autograph, and the other portion of the polarizing laminate is clamped between the lower chuck of the autograph, and measurement is performed. The second peel strength is also measured in the same manner as the first peel strength. The peel strength is calculated by determining the average peel force in Newtons (N) required to peel the test piece from a curve recording the peel of at least 100 mm, excluding the first 25 mm and the last 25 mm. From the obtained peel strength, the absolute value of the difference between the first peel strength and the second peel strength is calculated.

[0039] <Method for measuring retardation value> The retardation value of the protective layer can be measured using a "KOBRA-WPR" (590 nm) manufactured by Otsuka Measuring Instruments Co., Ltd. In the case of a laminate, a sharp blade such as a cutter knife is inserted into the interface between the protective layer and the polarizing layer of the laminate to separate the two layers. If an adhesive layer is attached to the protective layer, the part of the protective layer that is not attached is measured, or the adhesive layer is scraped off with a cutter knife or the like and only the protective layer is measured.

[0040] <Method for Evaluating Recyclability> After removing the peelable polarizing laminate from the optical lens, the lens (substrate) is crushed or remelted to form pellets, and a JIS K7139 dumbbell-shaped tensile test piece Type A is prepared by injection molding using the sample. The tensile elongation at break of the prepared test piece is measured in accordance with JIS K7161 using an Autograph AG-X plus manufactured by Shimadzu Corporation at a pulling rate of 100 mm / min, and the recyclability is evaluated according to the following criteria. When the polarizing laminate cannot be peeled, a test piece is prepared and evaluated in the same manner as above, except that the optical lens is used without peeling. A: Tensile yield elongation of 30% or more B: Tensile break elongation of less than 30%

[0041] <Durability evaluation method> A lens is cut using a lens processing machine so that the cross section of the laminate is exposed on the peripheral edge of the lens. The obtained lens is immersed in hot water at 100°C for 3 hours. The lens is removed from the hot water and the water infiltration from the periphery of the lens is visually observed. If the water infiltration depth is 2 mm or less according to the following criteria, it is judged to have good durability. A: Water infiltration depth is 2 mm or less B: Water infiltration depth is more than 2 mm

[0042] <Method for evaluating peelability> A cut is made with a cutter knife at the interface between the polarizing layer and the first protective layer located on the convex surface of the lens, and a further cut is made with the cutter knife up to the interface between the polarizing layer and the second protective layer. Peeling is then performed at the intended interface, and it is visually confirmed whether peeling can be performed at the intended interface. A: Peeling is possible at the intended peeling interface, and no polarizing layer remains on the peeled protective layer. B: Peeling is possible at the intended peeling interface, but a small amount of polarizing layer remains on the peeled protective layer. C: Peeling is not possible at the intended peeling interface.

[0043] The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the spirit of the present invention. The present disclosure is not limited to the embodiments, but is limited only by the scope of the claims.

[0044] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to the aspects of the following examples.

[0045] Example 1: An alicyclic polyamide resin (TROGAMID (registered trademark) myCX) was heated and melted using a film extruder adjusted to 280-300°C. The sheet extruded from a T-die was then cooled using a cooling roll and then uniaxially stretched at a stretch ratio of 1.50 using rolls rotating at different speeds while reheating, yielding a polyamide sheet with a thickness of 200 μm. One side of the resulting polyamide sheet was corona-treated, and its surface tension was confirmed to be 54 dyne. For lamination, a polyurethane adhesive (a mixture of two-component adhesives "TM-593" and "CAT-RT85" manufactured by Toyo-Morton at a mass ratio of 100:15) was applied to the corona-treated surface of the polyamide sheet to a thickness of 10 μm. The adhesive-coated side of the polyamide sheet was bonded to one side of a polarizing film (manufactured by Nippon Kayaku Co., Ltd.) containing polyvinyl alcohol and having a thickness of approximately 40 μm (first step). The resulting laminate was then wrapped around a cylindrical 6-inch plastic core. Subsequently, in the second step, one side of the polyamide sheet was subjected to corona treatment in the same manner as in the first step, and a surface tension of 54 dyne was confirmed. The same adhesive as in the first step was applied to this surface in a thickness of 10 μm, and this was then bonded to the polarizing layer surface of the laminate obtained in the first step to form a polarizing laminate (polarizing plate). The resulting polarizing plate was cut into a predetermined shape (a roughly rectangular shape with a pair of opposing edges curved outward in a roughly arc-like shape) using a Thomson blade. The cut polarizing plate was preheated at approximately 100°C for 1-2 minutes and then placed on a concave mold with a curvature radius of 87 mm and temperature-controlled at approximately 100°C. It was then vacuum-suctioned through a suction hole in the bottom of the mold and bent to obtain a polarizing laminate (polarizing plate) with a curved shape. The curved polarizing laminate was then placed on the concave surface of a lens mold installed in an injection molding machine, and the mold was closed. Thereafter, an alicyclic polyamide resin (TROGAMID (registered trademark) myCX) melt-kneaded at 280°C was injected at a pressure of 200 MPa to mold a polarizing laminate (polarizing lens). The obtained polarizing lens was processed into the shape of a lens to be fitted using a lens processing machine, yielding an optical lens in which the processed lens edge surface had the structure of first protective layer 101 / first adhesive layer 103 / polarizing layer 105 / second adhesive layer 104 / second protective layer 102 / base layer 201.

[0046] Examples 2 to 17 Polarizing laminates and optical lenses were obtained in the same manner as in Example 1, except that the materials used, the thickness of each layer, whether or not stretching was performed, and whether or not corona treatment was performed were changed as shown in Table 1. The physical properties of the obtained polarizing laminates and optical lenses are shown in Table 1. The specific materials used were as follows. In the case of an unstretched film, a protective layer was obtained by heating and melting the resin using a film extruder, and then cooling the sheet extruded from a T-die with a cooling roll.

[0047] (Resin of protective layer) Polycarbonate (PC): "Iupilon E2000 FE5111" manufactured by Mitsubishi Gas Chemical Co., Ltd. Triacetyl cellulose (TAC): "TD80UL" manufactured by Fujifilm Corporation (Adhesive) Urethane adhesive: Two-component adhesive "TM-593" and "CAT-RT85" manufactured by Toyo-Morton, mixed at a mass ratio of 100:15 Acrylic adhesive: "Saibinol AT-250" manufactured by Saiden Chemical Co., Ltd.

[0048] [Comparative Examples 1 to 5] Polarizing laminates and optical lenses were obtained in the same manner as in Example 1, except that the materials used, the thickness of each layer, whether or not stretching was performed, and whether or not corona treatment was performed were changed as shown in Table 1. The physical properties of the obtained polarizing laminates and optical lenses are shown in Table 1.

[0049] Comparative Examples 6 and 7 Polarizing laminates and optical lenses were obtained in the same manner as in Example 1, except that the materials used, the thickness of each layer, whether or not stretching was performed, and whether or not corona treatment was performed were changed to those shown in Table 1, and the first protective layer and the second protective layer were simultaneously attached to the polarizing layer. The physical properties of the obtained polarizing laminates and optical lenses are shown in Table 1. In the table, R indicates the retardation value (nm), and the absolute value of the difference indicates the absolute value of the difference between the peel strength between the polarizing layer and the first protective layer and the peel strength between the polarizing layer and the second protective layer.

[0050] According to the present disclosure, it is possible to provide an optical lens that is both recyclable and durable, and a polarizing laminate that provides the optical lens. In other words, the polarizing laminate of the present disclosure can be used in the production of an optical lens.

[0051] REFERENCE SIGNS LIST 100 Polarizing laminate, 101 First protective layer, 102 Second protective layer, 103 First adhesive layer, 104 Second adhesive layer, 105 Polarizing layer 200 Optical lens, 201 Substrate layer

Claims

1. A polarizing laminate in which a first protective layer and a second protective layer are laminated on both sides of a polarizing layer via an adhesive layer, characterized in that the peel strength of the polarizing laminate measured at a tensile speed of 100 mm / min is 2.0 to 30.0 N / 10 mm, and the absolute value of the difference between the peel strength between the polarizing layer and the first protective layer and the peel strength between the polarizing layer and the second protective layer is 0.2 to 8.0 N / 10 mm.

2. The polarizing laminate according to claim 1, wherein the adhesive layer is a layer containing a cured product of a urethane adhesive.

3. The polarizing laminate according to claim 1 or 2, wherein the adhesive layer has a thickness of 1.0 to 100.0 μm.

4. The polarizing laminate according to any one of claims 1 to 3, wherein at least one selected from the group consisting of the first protective layer and the second protective layer contains a polyamide resin.

5. The polarizing laminate according to claim 4, wherein the polyamide resin has a structure represented by the following formula (4): (In formula (4), R １ and R ２ each independently represents an alkyl group having 1 to 4 carbon atoms; ３ represents an alkylene group having 1 to 6 carbon atoms, n represents an integer of 1 or more, and p and q each independently represent an integer of 0 to 4.

6. The polarizing laminate according to any one of claims 1 to 5, wherein the retardation value of one or more layers selected from the group consisting of the first protective layer and the second protective layer is 300 nm or more.

7. The polarizing laminate according to any one of claims 1 to 6, wherein the polarizing layer contains polyvinyl alcohol.

8. An optical lens comprising the polarizing laminate according to any one of claims 1 to 7 and a substrate layer.

9. The optical lens according to claim 8, further comprising a substrate layer on a surface of the polarizing laminate.

10. The optical lens according to claim 9, wherein the substrate layer contains a polyamide resin having a structure represented by the following formula (4): (In formula (4), R １ and R ２ each independently represents an alkyl group having 1 to 4 carbon atoms; ３ represents an alkylene group having 1 to 6 carbon atoms, n represents an integer of 1 or more, and p and q each independently represent an integer of 0 to 4.

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