Polarizing laminate and optical lens
By adding stearic acid, UV absorbers, and heat stabilizers within specified ranges, the polarizing laminate and optical lens are protected from discoloration, enhancing manufacturing yield and quality.
Patent Information
- Application Number
- JP2023195129
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-11-16
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2043-11-16
AI Technical Summary
Existing polarizing laminates and optical lenses suffer from discoloration due to resin deterioration during the manufacturing process, leading to low manufacturing yield and unsuitability for use as products.
Incorporating additives such as stearic acid, ultraviolet absorbers, and heat stabilizers into the polarizing laminate structure, with specific content ranges to suppress discoloration, including a base layer with compounds A at 10 to 5000 ppm, UV absorber at 10 to 50,000 ppm, and heat stabilizer at 10 to 5000 ppm, along with a polyamide resin structure for protective layers.
The solution effectively suppresses discoloration, ensuring high manufacturing yield and quality of polarizing laminates and optical lenses by reducing resin deterioration and maintaining color tone.
Smart Images

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Figure 0007763224000002
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to a polarizing laminate and an optical lens. [Background technology]
[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 its apex is located on the mounting side of the adhesive layer in the thickness direction. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-227591 [Patent Document 2] International Publication No. 2016 / 158680 Summary of the Invention [Problem to be solved by the invention]
[0006] However, the present inventors have realized that in both the polarizing laminate of Patent Document 1 and the functional lens of Patent Document 2, the resin deteriorates due to heating during the manufacturing process, resulting in discoloration to brown or black (so-called fading). Polarizing laminates and lenses that have fading in this way are unsuitable for use as products, resulting in a low manufacturing yield. Therefore, there is a demand for polarizing laminates and optical lenses that are less susceptible to fading.
[0007] An object of the present disclosure is to provide a polarizing laminate and an optical lens that are suppressed from discoloring. [Means for solving the problem]
[0008] The present disclosure relates to the following: [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, the polarizing laminate includes a base layer, the substrate layer contains an additive, A polarizing laminate, wherein the additive satisfies one or more requirements selected from the group consisting of the following requirements (1) to (3): Requirement (1): the additive contains one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of the compounds A is 10 to 5000 ppm by mass relative to the base layer; Requirement (2): the additive contains an ultraviolet absorber, and the content of the ultraviolet absorber is 10 to 50,000 ppm by mass relative to the base layer; Requirement (3): The additive contains a heat stabilizer, and the content of the heat stabilizer is 10 to 5000 ppm by mass relative to the base layer. [2] The additive satisfies the requirement (2), The polarizing laminate according to [1], wherein the ultraviolet absorber comprises at least one selected from the group consisting of a benzotriazole compound, a triazine compound, and a cyanoacrylate compound. [3] The additive satisfies the requirement (3), The polarizing laminate according to [1] or [2], wherein the heat resistance stabilizer includes at least one selected from the group consisting of a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. [4] The polarizing laminate according to any one of [1] to [3], wherein the adhesive layer is a layer containing a cured product of a urethane adhesive. [5] The polarizing laminate according to any one of [1] to [4], wherein the adhesive layer has a thickness of 1.0 to 100.0 μm. [6] The polarizing laminate according to any one of [1] to [5], wherein at least one selected from the group consisting of the first protective layer and the second protective layer contains a polyamide resin. [7] The polarizing laminate according to [6], wherein the polyamide resin has a structure represented by the following formula (4): TIFF0007763224000001.tif38170 (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. [8] The polarizing laminate according to any one of [1] to [7], wherein the retardation value of at least one layer selected from the group consisting of the first protective layer and the second protective layer is 300 nm or more. [9] The polarizing laminate according to any one of [1] to [8], wherein the polarizing layer contains polyvinyl alcohol.
[10] An optical lens comprising the polarizing laminate according to any one of [1] to [9].
[11] The optical lens according to
[10] , wherein the substrate layer contains a polyamide resin having a structure represented by the following formula (4): TIFF0007763224000002.tif38170 (In formula (4), R 1 and R2 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. [Effects of the Invention]
[0009] According to the present disclosure, it is possible to provide a polarizing laminate and an optical lens in which discoloration is suppressed. [Brief explanation of the drawings]
[0010] [Figure 1] 1 is a cross-sectional view of a polarizing laminate according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION
[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 of the lower limit and any of the 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 polarizing laminate includes a base layer, which includes an additive, and the additive satisfies one or more requirements selected from the group consisting of the following requirements (1) to (3): Requirement (1): The additive contains one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of the compounds A is 10 to 5000 ppm by mass relative to the base layer. Requirement (2): The additive contains an ultraviolet absorber, and the content of the ultraviolet absorber is 10 to 50,000 ppm by mass relative to the base layer. Requirement (3): The additive contains a heat stabilizer, and the content of the heat stabilizer is 10 to 5000 ppm by mass relative to the base layer. For example, the additive may satisfy requirement (1), may satisfy requirement (2), may satisfy requirement (3), may satisfy requirements (1) and (2), may satisfy requirements (1) and (3), may satisfy requirements (2) and (3), or may satisfy requirements (1) to (3). Of these, it is preferable that the additive satisfy requirements (1) and (2).
[0013] When the substrate layer contains an additive, and the additive satisfies one or more requirements selected from the group consisting of the above requirements (1) to (3), discoloration of the substrate layer in the polarizing laminate can be suppressed. Requirements (1) to (3) are described in detail below.
[0014] [Requirement (1)] The additive contains one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of compound A is 10 to 5000 ppm by mass relative to the base layer. The content of compound A relative to the base layer is preferably 10 to 3000 ppm by mass, more preferably 10 to 1000 ppm by mass, even more preferably 10 to 500 ppm by mass, particularly preferably 10 to 300 ppm by mass, and especially preferably 10 to 200 ppm by mass. Within the above range, the base layer is less likely to become discolored.
[0015] The reason why such an effect is obtained is not clear, but the present inventors speculate as follows: Discoloration of the polarizing laminate occurs when the resin deteriorates due to heating during the manufacturing process. Resin deterioration is particularly likely to occur in the base layer. Compound A can suppress resin deterioration due to heating. If the content of Compound A is less than 10 ppm by mass, it becomes difficult to suppress resin deterioration. In addition, the resin blocks during the manufacturing process. If the content of Compound A exceeds 5000 ppm by mass, it becomes difficult to suppress resin deterioration. However, deterioration of the compound A itself may cause discoloration of the base layer. That is, by ensuring that the content of compound A in the substrate layer is within the above range, it is possible to suppress discoloration of the substrate layer and also suppress blocking of the resin. The content of compound A in the substrate layer can be adjusted by the amount of compound A added when producing the substrate layer. The content of compound A in the substrate layer can be measured by a known analytical method such as ICP-spectroscopy (ICP-AES).
[0016] As will be described in detail later, the polarizing laminate has a first protective layer and a second protective layer laminated on both sides of the polarizing layer via an adhesive layer. The polarizing laminate may further include other layers. When focusing particularly on the suppression of discoloration in each layer of the polarizing laminate, the content (ppm by mass) of compound A in each layer other than the substrate layer in requirement (1) can be determined. For example, when focusing particularly on the suppression of discoloration in the first protective layer of the polarizing laminate, the first protective layer contains an additive, the additive containing one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of compound A in the first protective layer is preferably 10 to 5,000 ppm by mass, more preferably 10 to 3,000 ppm by mass, even more preferably 10 to 1,000 ppm by mass, even more preferably 10 to 500 ppm by mass, particularly preferably 10 to 100 ppm by mass, and especially preferably 10 to 50 ppm by mass. When focusing on the second protective layer, when focusing on the adhesive layer, and when focusing on other layers, the same can be applied as in the case of the first protective layer.
[0017] The additive preferably contains a stearate. The stearate is not particularly limited, but examples thereof include monovalent metal salts such as lithium stearate, sodium stearate, and potassium stearate, and divalent metal salts such as magnesium stearate and calcium stearate. Of these, calcium stearate is more preferred.
[0018] [Requirement (2)] The additive contains an ultraviolet absorber, and the content of the ultraviolet absorber is 10 to 50,000 ppm by mass relative to the substrate layer. The content of the ultraviolet absorber relative to the substrate layer is preferably 10 to 30,000 ppm by mass, more preferably 10 to 10,000 ppm by mass, even more preferably 10 to 5,000 ppm by mass, particularly preferably 10 to 1,000 ppm by mass, and especially preferably 10 to 500 ppm by mass. Within the above range, the substrate layer is less likely to discolor, and the color tone of the substrate layer is also good.
[0019] The reason why such an effect is obtained is unclear, but the inventors speculate as follows: As described above, discoloration of the polarizing laminate occurs when the resin deteriorates due to heating during the manufacturing process. Resin deterioration is particularly likely to occur in the base layer. It is thought that the UV absorber melts when heated during the manufacturing process of the polarizing laminate and acts as a lubricant. This shortens the residence time of the resin, which is the raw material for the polarizing laminate, in the manufacturing equipment, and reduces the heat applied to the resin. As a result, deterioration of the resin due to heating is suppressed, and discoloration is less likely to occur in the polarizing laminate. That is, if the content of the UV absorber is less than 10 ppm by mass, the UV absorber's lubricant function will be insufficient, making it difficult to suppress resin deterioration. On the other hand, if the content of the UV absorber exceeds 50,000 ppm by mass, too much UV absorber will melt upon heating, which is undesirable as it can cause gas generation due to poor dispersion of the UV absorber. In addition, the polarizing laminate may be colored due to the color of the UV absorber. The content of the ultraviolet absorber in the substrate layer can be adjusted by the amount of ultraviolet absorber added when producing the substrate layer, and can be measured by known analytical means such as liquid chromatography mass spectrometry (LC / MS).
[0020] As with requirement (1), when particular attention is paid to suppressing discoloration in each layer of the polarizing laminate other than the base layer, requirement (2) can also be based on the standard for the content (ppm by mass) of the UV absorber for each layer. For example, when particular attention is paid to suppressing discoloration in the first protective layer, the first protective layer contains an additive, which contains a UV absorber, and the content of the UV absorber relative to the first protective layer is preferably 10 to 50,000 ppm by mass, more preferably 10 to 10,000 ppm by mass, even more preferably 10 to 5,000 ppm by mass, particularly preferably 10 to 1,000 ppm by mass, and especially preferably 10 to 500 ppm by mass. The same can be said when focusing on the second protective layer, the adhesive layer, or other layers.
[0021] The ultraviolet absorber is not particularly limited as long as it is a compound that absorbs ultraviolet light, and known ultraviolet absorbers can be used. For example, the ultraviolet absorber includes one or more selected from the group consisting of benzoxazine compounds, benzophenone compounds, benzotriazole compounds, triazine compounds, salicylic acid compounds, and cyanoacrylate compounds. Here, for example, a benzoxazine compound refers to a compound having a benzoxazine skeleton. Among these, the ultraviolet absorber preferably includes one or more selected from the group consisting of benzotriazole compounds, triazine compounds, and cyanoacrylate compounds, and more preferably includes a benzotriazole compound. As the benzotriazole compound, for example, Tinuvin 326 manufactured by BASF Japan Ltd. can be used. The ultraviolet absorbers may be used alone or in combination of two or more.
[0022] [Requirement (3)] The additive includes a heat stabilizer, and the content of the heat stabilizer is 10 to 5000 ppm by mass relative to the base layer. The content of the heat stabilizer relative to the base layer is preferably 10 to 3000 ppm by mass, more preferably 10 to 1000 ppm by mass, even more preferably 10 to 500 ppm by mass, particularly preferably 10 to 100 ppm by mass, and especially preferably 10 to 50 ppm by mass. Within the above range, the base layer is less likely to become discolored.
[0023] The reason why such an effect is obtained is unclear, but the inventors speculate as follows. As described above, discoloration of the polarizing laminate occurs when the resin deteriorates due to heating during the manufacturing process. Resin deterioration is particularly likely to occur in the base layer. It is thought that the heat stabilizer melts when heated during the manufacturing process of the polarizing laminate and stabilizes the polymer by capturing excess radicals. This shortens the residence time of the resin, which is the raw material for the polarizing laminate, in the manufacturing equipment, and reduces the heat applied to the resin. As a result, deterioration of the resin due to heating is suppressed, and discoloration is less likely to occur in the polarizing laminate. That is, if the content of the heat resistance stabilizer is less than 10 ppm by mass, the heat resistance stabilizer will not function sufficiently as a lubricant, making it difficult to suppress resin deterioration.On the other hand, if the content of the heat resistance stabilizer is more than 50,000 ppm by mass, too much of the heat resistance stabilizer will melt when heated, and it will no longer function as a lubricant, making it difficult to suppress resin deterioration. The content of the heat stabilizer in the substrate layer can be adjusted by the amount of the heat stabilizer added when producing the substrate layer, and can be measured by known analytical means such as liquid chromatography mass spectrometry (LC / MS).
[0024] As with requirements (1) and (2), when attention is particularly focused on suppressing discoloration in each layer other than the base layer of the polarizing laminate, the standard for the content (ppm by mass) of the heat stabilizer in requirement (3) can be set for each layer. For example, when attention is particularly focused on suppressing discoloration in the first protective layer, the first protective layer contains an additive, the additive contains a heat stabilizer, and the content of the heat stabilizer is is preferably 10 to 5000 ppm by mass, more preferably 10 to 3000 ppm by mass, even more preferably 10 to 1000 ppm by mass, even more preferably 10 to 500 ppm by mass, particularly preferably 10 to 100 ppm by mass, and especially preferably 10 to 50 ppm by mass, relative to the first protective layer. The same can be said when focusing on the second protective layer, the adhesive layer, or other layers.
[0025] The heat stabilizer is not particularly limited as long as it functions as a radical scavenger, and known heat stabilizers can be used. For example, the heat stabilizer includes one or more selected from phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Here, the phenolic antioxidant is an antioxidant having a phenolic hydroxy group in the molecule. For example, Irganox 1010 manufactured by BASF Japan Ltd. can be used as the phenolic antioxidant. Furthermore, the phosphorus-based antioxidant is an antioxidant having a phosphorus atom in the molecule. Furthermore, the sulfur-based antioxidant is an antioxidant having a sulfur atom in the molecule. The heat resistance stabilizers may be used alone or in combination of two or more kinds.
[0026] As described above, the polarizing laminate (200) 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 (200) also includes a base layer (201). The polarizing laminate may also include other layers. That is, the polarizing laminate may include a polarizing layer (105), a first adhesive layer (103) provided on a first surface of the polarizing layer, a second adhesive layer (104) provided on a second surface of the polarizing layer, a first protective layer (101) provided on a surface opposite the first adhesive layer from the side on which the polarizing layer is located, and a second protective layer (102) provided on a surface opposite the second adhesive layer from the side on which the polarizing layer is located. The arrangement of the substrate layer (201) is not particularly limited. For example, the substrate layer (201) may be disposed on the surface of the first protective layer (101) opposite the polarizing layer (105), or on the surface of the second protective layer (102) opposite the polarizing layer (105). This configuration facilitates control of the adhesive strength between the polarizing laminate and the substrate layer. In this configuration, the protective layer (first protective layer or second protective layer) can be used for bonding to the substrate layer. The method for forming this configuration is not particularly limited. For example, a method may be used in which a resin is injection-molded onto a laminate in which the first protective layer and the second protective layer are laminated on both sides of the polarizing layer via an adhesive layer, and the laminate and the substrate layer are thermally welded together. In addition, another layer may be provided between the substrate layer (201) and the protective layer (first protective layer (101) and second protective layer (102)). Each layer that can constitute the polarizing laminate will be described below.
[0027] (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.
[0028] The polyvinyl alcohol is not particularly limited, but examples thereof include saponified vinyl acetate polymers, vinyl acetate and copolymerizable monomers other than vinyl acetate (for example, unsaturated carboxylic acids, unsaturated Examples of the saponifiable resins include saponified copolymers with hydroxypropyl methyl acrylate and hydroxypropyl methyl acrylate (e.g., hydroxypropyl methyl acrylate ... The number-average polymerization degree of polyvinyl alcohol is not particularly limited, but may be, for example, 1,000 to 10,000, or 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 (for example, 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%.
[0029] 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.
[0030] (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 contains a thermoplastic resin, and more preferably is made of 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. Of these, polyamide resins are preferred. The polyamide resin is not particularly limited, and examples thereof include aliphatic polyamide resins and aromatic polyamide resins. The aliphatic polyamide resin may have a linear structure, may have a branched structure, or may have a cyclic structure. Among them, it is preferable that the aliphatic polyamide resin has a cyclic structure. That is, the polyamide resin is preferably an alicyclic polyamide resin. The alicyclic polyamide resin has excellent transparency. The alicyclic polyamide resin is available, for example, as Trogamid (manufactured by Polypla-Evonik) and Grilamid (manufactured by EMS). The resin layer may contain one or more of these resins. The protective layers (first and second protective layers) may contain the same material or different materials. That is, one or more layers selected from the group consisting of the first and second protective layers may contain the above-mentioned material.
[0031] The alicyclic polyamide resin can be obtained by combining suitable components from among one or more components selected from the group consisting of alicyclic diamines and alicyclic dicarboxylic acids, aliphatic diamines other than alicyclic diamines, and aliphatic dicarboxylic acids other than alicyclic dicarboxylic acids, and polymerizing the combined components using a known method. The alicyclic diamine may, for example, be a compound represented by the following formula (1). [ka] (In formula (1), A 1 and A2 each independently represents a cycloalkylene group having 5 to 10 carbon atoms (preferably 6 to 8, more preferably 6), and X 1 represents an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4, more preferably 1 to 3).
[0032] The alicyclic dicarboxylic acid may, for example, be a compound represented by the following formula (2). [ka] (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).
[0033] 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 an aliphatic dicarboxylic acid A). Examples of the aliphatic dicarboxylic acid A include compounds represented by the following formula (3). [ka] (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.)
[0034] The alicyclic polyamide resin preferably has a structure represented by the following formula (4). [ka] (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 3represents 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, and 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, and even more preferably 0 to 1).
[0035] The number average molecular weight of the polyamide resin is not particularly limited, but is, for example, 0.6×10 4 ~3.0×10 5 may be 0.6 x 10 4 ~2.0×10 5 Preferably, it is 1.0 × 10 4 ~1.5×10 5 More preferably, it is 2.0 × 10 4 ~1.0×10 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.
[0036] The thickness of the protective layer is not particularly limited, and 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.
[0037] 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 it is particularly 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, it is possible to suppress the generation of white spots in the protective layer. 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, and even more preferably 450 to 5,000 nm. It is preferable that the wavelength is 500 to 4000 nm, and it is particularly preferable that the wavelength is 550 to 3000 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 direction perpendicular to that, and d is the thickness of the protective layer. The retardation value can be controlled by the stretching ratio when manufacturing the protective layer, the amount of resin discharged, and the thickness of the protective layer.
[0038] (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 any known method 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, with urethane adhesives being preferred. The term "urethane adhesive" refers to an adhesive containing a polyurethane resin or an adhesive containing an isocyanate component and a diol component. That is, the urethane adhesive may be a one-component adhesive containing a polyurethane resin, or a two-component curing adhesive (i.e., a reaction-curing adhesive) containing an isocyanate component and a diol component. As the isocyanate component and the diol component, a urethane prepolymer obtained by reacting the isocyanate component and the diol component can also be used.
[0039] The adhesive layer may contain one or more of these materials. Furthermore, the adhesive layers (first adhesive layer and second adhesive layer) may contain the same material or different materials. 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.
[0040] The thickness of the adhesive layer is not particularly limited, and 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. The thicknesses of the adhesive layers (first adhesive layer and second adhesive layer) may be the same or different.
[0041] (base material layer) The material used for the substrate layer is not particularly limited, but 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 layer, an optical lens having high lightness, toughness, and chemical resistance can be formed. As the resin, the resins described in the protective layer section can be used, and as the polyamide resin, the polyamide resins described in the protective layer section can be used. The substrate layer may also contain various additives other than the additives mentioned above, such as a plasticizer, a colorant, a flame retardant, an antistatic agent, and the like.
[0042] The thickness of the substrate layer is not particularly limited, but may be, for example, 1 to 20 mm, preferably 2 to 20 mm, more preferably 3 to 10 mm, and even more preferably 3 to 5 mm.
[0043] 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 an example of the method is to form a flat polarizing laminate and then subject the polarizing laminate to bending processing.
[0044] <Optical lenses> The optical lens preferably includes a polarizing laminate. 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.
[0045] 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.
[0046] The methods for measuring and evaluating the physical properties of the polarizing laminate and the optical lens will be described below.
[0047] <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, insert the sharp edge of a cutter knife or similar 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, measure the part of the protective layer that is not attached, or scrape off the adhesive layer with a cutter knife or similar and measure only the protective layer.
[0048] <Blocking evaluation method (Test 1)> The bulk density of the injection molding material is measured three times in accordance with JIS K-6720-2 (ISO 1060-2).The difference between the maximum and minimum bulk density values obtained is then divided by the arithmetic mean value of the three values, and the value is used to evaluate the material according to the following criteria.
[0049] [Evaluation criteria] A: The value of {(maximum value - minimum value) / arithmetic mean value} x 100 is less than 10. B: The value of {(maximum value - minimum value) / arithmetic mean value} x 100 is 10 or more.
[0050] <Evaluation method for ultraviolet transmittance (Test 2)> Measurement was carried out in accordance with JIS K7375 (ISO 13468-2) using a color difference meter (CM5 manufactured by Konica Minolta) using a polarizing laminate having a thickness of 2 mm.
[0051] [Evaluation criteria] A: Transmittance at 400 nm is less than 10%. B: Transmittance at 400 nm exceeds 10%.
[0052] <Evaluation method for discoloration (Test 3)> A 2 mm thick laminate that does not include an injection molding material or a polarizing layer is left in an environment at 200°C for 30 minutes, and the color difference is measured using reflected light with a spectrophotometer (CM5 manufactured by Konica Minolta).
[0053] [Evaluation criteria] A: The color difference ΔE is less than 3. B: The color difference ΔE is 3 or more.
[0054] <Evaluation method for discoloration (Test 4)> The evaluation of discoloration is carried out by using a microscope (Keyence, VHX-7000) to shine transmitted light onto the lens and observe the size of the discoloration (black or brown foreign matter).
[0055] [Evaluation criteria] A: Fewer than three burns with a diameter of more than 50 μm are observed. B: Three or more burns with a diameter of more than 50 μm are observed.
[0056] <Overall Judgment> The evaluation will be based on the following criteria: A: All evaluation results from the above evaluation methods were A. B: Includes one or more B ratings from the above evaluation methods.
[0057] 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. [Example]
[0058] 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.
[0059] [Example 1] Alicyclic polyamide resin (TROGAMID® 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 reheated while being uniaxially stretched at a stretch ratio of 1.50 using rolls rotating at different speeds to obtain a 200 μm thick polyamide sheet. One side of the resulting polyamide sheet was coated with a polyurethane adhesive (a 100:15 mixture of two-component adhesives "TM-593" and "CAT-RT30" manufactured by Toyo-Morton Co., Ltd.) to a thickness of 10 μm. The adhesive-coated side of the polyamide sheet was bonded to both sides of a 40 μm thick polarizing film containing polyvinyl alcohol (manufactured by Nippon Kayaku Co., Ltd.) to form a polarizing plate (laminate). The resulting polarizing plate was then cut into the desired shape (a pair of opposing edges of a roughly rectangular shape curved outward in a roughly arc shape) using a Thomson blade. The cut polarizing plate was preheated to about 100°C for 1 to 2 minutes, and then placed on a concave mold with a curvature radius of 87 mm, whose temperature was adjusted to about 100°C. It was then vacuum-sucked through a suction hole at the bottom of the mold and bent to obtain a polarizing plate (laminate) with a curved surface shape (curved shape). The injection molding material was prepared by sprinkling calcium stearate (manufactured by Shiraishi Calcium Co., Ltd.) as compound A onto an alicyclic polyamide resin (Trogamid (registered trademark) myCX) so that the concentration of the compound A was 200 ppm by mass relative to the injection molding material.
[0060] A curved polarizing plate was placed on the concave surface of a lens mold installed in an injection molding machine, and the mold was closed. The injection molding material prepared by the above method and melt-kneaded at 280°C was then injected at a pressure of 200 MPa to mold a polarizing laminate (polarizing lens). The obtained polarized lens was processed into the shape of a lens to be fitted using a lens processing machine, and an optical lens was obtained in which the end face of the processed lens had a structure of first protective layer 101 / first adhesive layer 103 / polarizing layer 105 / second adhesive layer 104 / second protective layer 102 / base material layer 201.
[0061] The polarizing laminate was evaluated according to the above-mentioned evaluation methods and criteria, and the evaluation results are shown in Table 1-1.
[0062] [Examples 2 to 60] A polarizing laminate was obtained in the same manner as in Example 1, except that the contents of Compound A, UV absorber, and heat stabilizer were changed to the values shown in Tables 1-1 and 1-2. The physical properties of the obtained polarizing laminate are shown in Tables 1-1 and 1-2. When adding an ultraviolet absorber or heat stabilizer to the injection molding resin, a material prepared by mixing an ultraviolet absorber (Tinuvin 326, manufactured by BASF Japan) and a heat stabilizer (Irganox 1010, manufactured by BASF Japan) or either one alone with an alicyclic polyamide resin (Trogamid (registered trademark) myCX) was melt-kneaded at 280°C using a twin-screw extruder to produce cylindrical resin pellets. Calcium stearate (manufactured by Shiraishi Calcium Co., Ltd.) was then sprinkled on the resin pellets as compound A to produce a material for injection molding.
[0063] [Comparative Examples 1 to 13] A polarizing laminate was obtained in the same manner as in Example 1, except that the contents of Compound A, UV absorber, and heat stabilizer were changed to the values shown in Tables 1-1 and 1-2. The physical properties of the obtained polarizing laminate are shown in Tables 1-1 and 1-2. When a UV absorber or heat stabilizer was added to the injection-molded resin, the same method as described in the above columns for Examples 2 to 60 was used. [Table 1-1] [Table 1-2] In Tables 1-1 and 1-2, Compound A indicates the content (ppm by mass) of stearic acid or a stearate salt in the injection molding material, UV absorber indicates the content (ppm by mass) of the UV absorber in the injection molding material, and heat stabilizer indicates the content (ppm by mass) of the heat stabilizer in the injection molding material. [Industrial Applicability]
[0064] According to the present disclosure, it is possible to provide a polarizing laminate and an optical lens in which discoloration is suppressed. [Explanation of symbols]
[0065] 200 Polarizing laminate, 101 First protective layer, 102 Second protective layer, 103 First adhesive layer, 104 Second adhesive layer, 105 Polarizing layer, 201 Base 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, the polarizing laminate includes a base layer, the substrate layer contains a polyamide resin and an additive, the polyamide resin is an alicyclic polyamide resin, A polarizing laminate, characterized in that the additive satisfies the following requirement (1): Requirement (1): The additive contains one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of the compounds A is 10 to 5000 ppm by mass relative to the base layer.
2. 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, the polarizing laminate includes a base layer, the substrate layer contains a polyamide resin and an additive, the polyamide resin is an alicyclic polyamide resin, A polarizing laminate, characterized in that the additive satisfies the following requirement (3): Requirement (3): The additive contains a heat stabilizer, and the content of the heat stabilizer is 10 to 5000 ppm by mass relative to the base layer (however, except when the content of the heat stabilizer is 908 ppm by mass relative to the base layer, this excludes cases where the heat stabilizer is a compound that has an aromatic ring, is composed only of carbon atoms, oxygen atoms, and hydrogen atoms, does not contain an ester group, and has 1 or 0 substituents selected from the group consisting of hydroxyl groups and ether groups bonded to the aromatic ring).
3. 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, the polarizing laminate includes a base layer, the substrate layer contains a polyamide resin and an additive, the polyamide resin is an alicyclic polyamide resin, A polarizing laminate, wherein the additive satisfies the following requirements (1), (2), and (3-1): Requirement (1): The additive contains one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of the compounds A is 10 to 5000 ppm by mass relative to the base layer; Requirement (2): the additive contains an ultraviolet absorber, and the content of the ultraviolet absorber is 10 to 5000 ppm by mass relative to the base layer (however, excluding the cases where the content of the ultraviolet absorber is 1000 ppm by mass or 4405 ppm by mass relative to the base layer, and where the ultraviolet absorber is at least one UV absorber having at least one substituted benzoyl group); Requirement (3-1): The additive contains a heat stabilizer, and the content of the heat stabilizer is 10 to 5000 ppm by mass relative to the base layer.
4. The polarizing laminate according to claim 1, wherein the additive satisfies one or more requirements selected from the group consisting of the following requirements (2-1) and (3-1): Requirement (2-1): The additive contains an ultraviolet absorber, and the content of the ultraviolet absorber is 10 to 5,000 ppm by mass relative to the base layer; Requirement (3-1): The additive contains a heat stabilizer, and the content of the heat stabilizer is 10 to 5000 ppm by mass relative to the base layer.
5. The polarizing laminate according to claim 2, wherein the additive satisfies one or more requirements selected from the group consisting of the following requirements (1) and (2-1): Requirement (1): The additive contains one or more compounds A selected from the group consisting of stearic acid and stearates, and the content of the compounds A is 10 to 5000 ppm by mass relative to the base layer; Requirement (2-1): The additive contains an ultraviolet absorber, and the content of the ultraviolet absorber is 10 to 5000 ppm by mass relative to the base layer.
6. The polarizing laminate according to claim 3 , wherein the ultraviolet absorber comprises at least one selected from the group consisting of a benzotriazole compound, a triazine compound, and a cyanoacrylate compound.
7. The polarizing laminate according to claim 2 , wherein the heat stabilizer comprises at least one selected from the group consisting of a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant.
8. 8. The polarizing laminate according to claim 7, wherein the heat resistance stabilizer is pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].
9. 7. The polarizing laminate according to claim 6, wherein the ultraviolet absorber is 2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol.
10. 10. The polarizing laminate according to claim 1, wherein the adhesive layer is a layer containing a cured product of a urethane adhesive.
11. 10. The polarizing laminate according to claim 1, wherein the adhesive layer has a thickness of 1.0 to 100.0 μm.
12. The polarizing laminate according to any one of claims 1 to 9, wherein at least one selected from the group consisting of the first protective layer and the second protective layer contains a polyamide resin.
13. The polarizing laminate according to claim 12 , wherein the polyamide resin has a structure represented by the following formula (4): 【Chemistry 1】 (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.
14. The polarizing laminate according to any one of claims 1 to 9, 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.
15. 10. The polarizing laminate according to claim 1, wherein the polarizing layer contains polyvinyl alcohol.
16. An optical lens comprising the polarizing laminate according to any one of claims 1 to 9.
17. The optical lens according to claim 16 , wherein the substrate layer contains an alicyclic polyamide resin having a structure represented by the following formula (4): 【Chemistry 2】 (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.
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