Curable optical adhesive composition

Abstract

To provide a curable optical adhesive composition in which the cured product exhibits excellent hardness and elongation with superior temperature stability, enabling the precise maintenance of the position of in-vehicle optical components under the operating temperature and motion conditions of an automobile. [Solution] A curable optical adhesive composition comprising a curable optical resin composition containing a (meth)acryloyloxy group-containing (meth)acrylic polymer (A), a high glass transition temperature vinyl monomer (B), a rigid filler (C), and a polymerization initiator (D), wherein the cured product of the curable optical resin composition is an optical resin having a glass transition temperature of 125°C or higher and an elongation of 3% or higher at room temperature.

Description

Technical Field

[0001] The present invention relates to a curable optical adhesive composition, and particularly to a curable optical adhesive composition for bonding in-vehicle optical components.

Background Art

[0002] Patent Document 1 describes an epoxy-based dual-curable adhesive composition useful for bonding optical components of camera modules mounted in automobiles, smartphones, etc. The dual-curable adhesive composition of Patent Document 1 uses a tetrakis(pentafluorophenyl)borate compound instead of a conventional antimony-containing compound as a thermal cationic polymerization initiator, resulting in an adhesive composition with low toxicity, capable of low-temperature curing, and having high heat resistance of the cured product.

[0003] On the other hand, in recent years, there has been an increasing demand for automobiles to mount large optical modules. For example, LiDAR is a technology that irradiates laser light and measures the distance and shape to an object based on the information of the reflected light. In-vehicle LiDAR is a system that accurately detects and measures the surrounding situation during the driving of an automobile, and requires a larger and higher-performance camera module compared to smartphones, etc.

[0004] When the in-vehicle optical module becomes larger, the components also become larger and heavier, and the load applied to each component due to vibration during automobile operation also increases. The curable optical adhesive composition is formulated to have high mechanical strength and hardness of the cured product in order to accurately maintain the installation position of the optical component over a wide range of automobile operating temperatures from below freezing to nearly 100°C. However, such a formulation means that, on the other hand, the cured product is inferior in flexibility, and there is a problem that it is likely to be damaged when a large load is applied to the component in a short time due to vibration.

[0005] Patent Document 2 describes a method for curing a photocurable rubber composition. The photocurable rubber composition is a composition comprising a (meth)acrylic polymer containing a (meth)acryloyloxy group having a predetermined chemical structure and a photoradical polymerization initiator. The method for curing it is irradiation with a UV-LED lamp. For the purpose of improving the properties of the cured product, monomers having radical polymerizable groups such as (meth)acrylic groups may be used in combination with the above composition.

[0006] Patent Document 2 lists a wide range of industrial components as applications for the cured product of the composition, and these are intended for components that utilize rubber properties and elasticity, such as sealing, shock absorption, impact, pressure distribution, vibration damping, sound absorption, sound insulation, and improving the feel of parts that come into contact with the human body. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-147584 [Patent Document 2] Japanese Patent Publication No. 2020-147616 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The present invention solves the aforementioned problems and aims to provide a curable optical adhesive composition in which the cured product exhibits excellent hardness and elongation with good temperature stability, and can accurately maintain the position of in-vehicle optical components under the temperature and motion conditions in which automobiles are operated. [Means for solving the problem]

[0009] The present invention provides the following embodiments. [1] A curable optical adhesive composition comprising a curable optical resin composition containing a (meth)acryloyloxy group-containing (meth)acrylic polymer (A), a high glass transition temperature vinyl monomer (B), a rigid filler (C), and a polymerization initiator (D), A curable optical adhesive composition wherein the cured product of the curable optical resin composition is an optical resin having a glass transition temperature of 125°C or higher and an elongation of 3% or higher at room temperature.

[0010] [2] A curable optical adhesive composition according to embodiment 1, wherein monomer (B) has a glass transition temperature of 80 to 260°C, preferably 100 to 250°C, more preferably 120 to 250°C.

[0011] [3] A curable optical adhesive composition according to embodiment 1 or 2, wherein the rigid filler (C) has a coefficient of linear expansion of 20 ppm / °C or less, preferably 12 ppm / °C or less, and more preferably 10 ppm / °C or less.

[0012] [4] A curable optical adhesive composition according to any of embodiments 1 to 3, wherein the mass ratio A / B of polymer (A) to monomer (B) is 0.3 to 3, preferably 0.5 to 2, more preferably 0.6 to 1.5, and even more preferably 0.8 to 1.25.

[0013] [5] A curable optical adhesive composition according to any of embodiments 1 to 4, wherein the mass ratio (C / (A+B)) of the hard filler (C) to the total resin (A+B) is 1 to 3, preferably 1.2 to 2.5, and more preferably 1.5 to 2.

[0014] [6] The polymerization initiator (D) is a curable optical adhesive composition according to any of embodiments 1 to 5, comprising a photopolymerization initiator (D1) and a thermal polymerization initiator (D2).

[0015] [7] A curable optical adhesive composition according to any of embodiments 1 to 6, wherein polymer (A) has a number average molecular weight of 3,000 to 100,000, preferably 10,000 to 90,000, and more preferably 30,000 to 80,000.

[0016] [8] The monomer (B) is at least one selected from the group consisting of isobornyl acrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, and combinations thereof, and is a curable optical adhesive composition according to any one of Aspects 1 to 7.

Advantages of the Invention

[0017] According to the present invention, there is provided a curable optical adhesive composition in which the cured product exhibits excellent hardness and excellent elongation in terms of temperature stability, and can accurately maintain the position of in-vehicle optical components under the temperature conditions and motion conditions under which an automobile is operated. Examples of in-vehicle optical components include components of large in-vehicle optical modules such as in-vehicle cameras for LiDAR.

Modes for Carrying Out the Invention

[0018] Hereinafter, an embodiment of the present invention will be described in detail. However, the scope of the present invention is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present invention. Also, when a plurality of upper limit values and lower limit values are described for specific parameters, any upper limit value and lower limit value can be combined to form a suitable numerical range.

[0019] <000资源标签专利文本光学树脂光学部件​​​​​​​​​(Meta)acryloyloxy group-containing (meth)acrylic polymers include polymers in which the main chain is a (meth)acrylate polymer and having a (meta)acryloyloxy group can be used. Such polymers are preferably produced by anionic polymerization or radical polymerization, and radical polymerization is more preferable because of the versatility of monomers or ease of control. Among radical polymerizations, it is preferably produced by living radical polymerization or radical polymerization using a chain transfer agent, living radical polymerization method is more preferable, and atom transfer radical polymerization method is particularly preferable. When using the living radical polymerization method, a polymer having a (meta)acryloyloxy group at the polymer chain end can be obtained.

[0022] (Meta)acryloyloxy group-containing (meth)acrylic polymer (A) has a number average molecular weight of 3,000 to 100,000, preferably 10,000 to 90,000, and more preferably 30,000 to 80,000. If the molecular weight is too low, the flexibility of the cured product is impaired and the elongation tends to decrease. On the other hand, if it is too high, the viscosity of the curable optical adhesive composition tends to be high and handling becomes difficult.

[0023] Examples of (meth)acryloyloxy group-containing (meth)acrylic polymers include, for example, poly(n-butyl acrylate / ethyl acrylate / methoxyethyl acrylate) having acryloyl groups at both ends as described in Synthesis Example 1 of Patent Document 2, poly(n-butyl acrylate / 2-ethylhexyl acrylate) having acryloyl groups at both ends as described in Synthesis Example 2, poly(n-butyl acrylate) having acryloyl groups at both ends as described in Synthesis Example 3; methacryloyl group-terminated poly(n-butyl acrylate) described in Example 3 of Japanese Patent Application Publication No. 2000-72816; methacryloyl group-terminated poly(n-butyl acrylate) described in Example 6; WO2012 / 0 The following can be used: n-butyl polyacrylate having acryloyl groups at both ends as described in Production Example 1 of Publication No. 08127; n-butyl polyacrylate having an acryloyl group at one end as described in Production Example 2; poly(n-butyl acrylate / ethyl acrylate / 2-methoxyethyl acrylate) having acryloyl groups at both ends as described in Production Example 1 of Publication No. WO2005 / 000927; poly(n-butyl acrylate / 2-ethylhexyl acrylate) having acryloyl groups at both ends as described in Production Example 2 of Publication No. WO2006 / 112420; poly(2-ethylhexyl acrylate) having acryloyl groups at both ends as described in Production Example 3; and so on.

[0024] Many polymers such as polymethyl methacrylate (MMA), polystyrene (St), poly(acrylonitrile (AN) / St), poly(2-hydroxyethyl methacrylate (HEMA) / MMA), and poly(HEMA / butyl methacrylate (BMA)) are commercially available as the backbone components of (meth)acrylic polymers containing (meth)acryloyloxy groups.

[0025] Examples of commercially available (meth)acrylic polymers containing (meth)acryloyloxy groups include macromonomers AA-6, AA-714, AB-6, AJ-7, AN-6, AS-6, AW-6, AZ-8, HA-6, HN-6, and HS-6 from Toagosei Co., Ltd., and XMAP RC-100C, RC-200C, and RC-300C from Kaneka Corporation (all are trade names).

[0026] <(B) High glass transition temperature vinyl monomers> The curable optical resin composition, by containing a high glass transition temperature (Tg) vinyl monomer, can provide a cured product that maintains high hardness over the operating temperature of an automobile.

[0027] As high-Tg vinyl monomers, for example, vinyl monomers having a Tg of 80 to 260°C, preferably 100 to 250°C, and more preferably 120 to 250°C can be used. The Tg of a high-Tg vinyl monomer refers to the Tg exhibited by its homopolymer. The Tg exhibited by the monomer homopolymer is generally known and adopted (e.g., "Collection of Selection and Usage Examples of Functional Monomers," Technical Information Association, 2017; Macromolecules 1996, 29, 8954-8959).

[0028] Specific examples of high-Tg vinyl monomers are shown below.

[0029] [Table 1]

[0030] Among these, it is preferable to use high-Tg vinyl monomers such as isobornyl acrylate, isobornyl methacrylate, and 3,3,5-trimethylcyclohexyl methacrylate, with isobornyl acrylate and isobornyl methacrylate being particularly preferred.

[0031] <(C) Hard filler> The curable optical adhesive composition of the present invention contains a rigid filler. By using a rigid filler, the coefficient of thermal expansion of the cured product of the curable optical adhesive composition can be controlled. The rigid filler is made of a material having a coefficient of thermal expansion of 20 ppm / °C or less, preferably 12 ppm / °C or less, and more preferably 10 ppm / °C or less.

[0032] Preferred hard fillers are transparent inorganic fillers. Specific examples of transparent inorganic fillers include silica fillers such as colloidal silica, hydrophobic silica, fine silica, and nanosilica, as well as silica beads, glass beads, and alumina beads.

[0033] The average particle size of the hard filler (or its average maximum diameter if it is not granular) is not particularly limited, but it is preferable if it is 0.01 μm or larger, as this results in a curable optical adhesive composition with excellent handling properties. Furthermore, it is preferable if the average particle size of the hard filler (or its average maximum diameter if it is not granular) is 50 μm or smaller, as this results in uniform dispersion within the curable optical adhesive composition. The average particle size of the hard filler is preferably 0.1 to 30 μm, more preferably 1 to 20 μm. In this invention, the average particle size of the hard filler is measured using a dynamic light scattering nanotrack particle size analyzer.

[0034] Commercially available hard fillers include glass beads (product name "EGB210C" (average particle size 18 μm), manufactured by Potters-Balotini), high-purity synthetic spherical silica (product name "SO-E5" (average particle size 2 μm), product name "SO-E2" (average particle size 0.6 μm), manufactured by Admatex), silica (product name "FB7SDX" (average particle size 10 μm), manufactured by Ryusen), and silica (product name "TS-10-034P" (average particle size 20 μm), manufactured by Micron). Hard fillers may be used individually or in combination of two or more types.

[0035] <Amounts of ingredients A, B, and C> The curable optical resin composition has a mass ratio A / B of polymer (A) to monomer (B) of 0.3 to 3. If the mass ratio is less than 0.3, the flexibility to absorb the load applied to the in-vehicle optical component may be insufficient. If the mass ratio exceeds 3, the hardness of the cured product may be insufficient at the operating temperature of the automobile. The mass ratio is preferably 0.5 to 2, more preferably 0.6 to 1.5, and even more preferably 0.8 to 1.25.

[0036] The curable optical resin composition has a mass ratio C / (A+B) of 1 to 3 between the hard filler (C) and the total resin components, i.e., the polymer (A) and monomer (B). If the mass ratio is less than 1, the coefficient of thermal expansion of the cured product may not be able to keep up with the thermal expansion behavior of the bonded optical component. If the mass ratio exceeds 3, the viscosity of the adhesive may be too high, impairing the coatability. The mass ratio is preferably 1.2 to 2.5, more preferably 1.5 to 2.

[0037] <(D) Polymerization initiator> The curable optical resin composition contains a photoradical polymerization initiator (D1). By using the photoradical polymerization initiator (D1), it can be easily cured in a temperature environment ranging from room temperature to slightly above room temperature. Preferably, the curable optical resin composition contains a thermal radical polymerization initiator (D2). By using a thermal radical initiator and curing it sufficiently in a high-temperature environment, the hardness of the cured product of the curable optical resin composition can be improved.

[0038] Examples of photoradical polymerization initiators include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxycyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 4-phenylbenzophenone, 4-phenoxybenzophenone, 4,4'-diphenylbenzophenone, and 4,4'-diphenoxybenzophenone. Among these, 2-hydroxy-2-methyl-1-phenyl-propan-1-one is preferred.

[0039] The content of the photoradical polymerization initiator can be appropriately selected depending on the amount of light irradiation and additional heating temperature.

[0040] Examples of thermal radical polymerization initiators include azobisobutylnitrile, benzoyl peroxide, tert-butyl peroxypivalate, tert-butyl peroxyneohexanoate, tert-hexyl peroxyneohexanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, cumyl peroxyneohexanoate, cumyl peroxyneodecanoate, and 1,1,3,3-tetramethylbutyl peroxy2-ethylhexanoate. Among these, 1,1,3,3-tetramethylbutyl peroxy2-ethylhexanoate is preferred.

[0041] The content of the thermal radical polymerization initiator can be appropriately selected depending on the heating temperature, the amount of oxygen present during radical polymerization, etc.

[0042] <Characteristics of hardened material> The cured product of the curable optical resin composition has a Tg of 125°C or higher. The Tg of the curable optical resin composition is determined from the peak value of the loss tangent measured using a dynamic viscoelasticity measuring instrument.

[0043] If the Tg of the cured product is less than 125°C, the cured product of the curable optical adhesive composition is prone to softening when the automobile reaches high temperatures, which can cause the position of the on-board optical components to shift. If the Tg of the cured product is too high, it becomes brittle. Generally, the upper limit of the Tg of the cured product is 200°C or less. The range of the Tg of the cured product is, for example, 125 to 200°C, preferably 140 to 190°C, and more preferably 150 to 180°C.

[0044] The cured product of the curable optical resin composition has an elongation of 3% or more at room temperature. The elongation of the curable optical resin composition is the elongation at break measured according to the sample and method in accordance with JIS K6251.

[0045] If the elongation rate of the cured product at room temperature is less than 3%, the cured product of the curable optical adhesive composition is brittle and prone to breakage when a large load is applied to the optical components in a short period of time due to vibrations of an automobile. The cured product has the problem of becoming more deformable as the elongation rate increases. Generally, the upper limit of the elongation rate of the cured product is 100% or less. The elongation rate of the cured product is preferably 5% or more, more preferably 7% or more. The range of the elongation rate of the cured product is, for example, 3 to 100%, preferably 5 to 80%, more preferably 7 to 73%, and even more preferably 10 to 61%.

[0046] 2.Optional ingredients The curable optical adhesive composition of the present invention may contain the following components in addition to the components of the curable optical resin composition.

[0047] <Polyfunctional monomers> The curable optical resin composition may also contain polyfunctional monomers. Using polyfunctional monomers can further improve the tensile strength of the cured product.

[0048] Polyfunctional monomers are monomers that have three or more polymerizable carbon-carbon double bonds in their molecule. Polymerizable carbon-carbon double bonds include vinyl groups, allyl groups, (meth)acrylic groups, (meth)acryloyl groups, etc.

[0049] Specific examples of polyfunctional monomers include trimethylolpropane triacrylate, neopentyl glycol polypropoxy diacrylate, neopentyl glycol diacrylate, trimethylolpropane polyethoxy triacrylate, bisphenol F polyethoxy diacrylate, bisphenol A polyethoxy diacrylate, and dipentaerythritol polyhexanolide hexaacrylate. Among these, it is preferable to use polyfunctional monomers such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate, with trimethylolpropane triacrylate being particularly preferred.

[0050] When the curable optical adhesive composition contains a polyfunctional monomer, its content is not particularly limited, but is, for example, 0 to 5% by mass, preferably 0 to 3% by mass, and more preferably 0 to 2% by mass, based on the entire curable optical resin composition.

[0051] <Thixotropic agent> The curable optical adhesive composition may contain a thixotropic agent such as fumed silica. Using a thixotropic agent can suppress stringing and spreading during application of the curable optical adhesive composition. Furthermore, fumed silica also functions as an inorganic filler, and its use can further improve the tensile strength of the cured product. Commercially available fumed silica products include "HDK H2000" manufactured by Asahi Kasei Wacker Silicone Co., Ltd.; "Cab-O-Sil TS-720" and "TS-530" manufactured by Cabot Corporation; and "Aerosil R974" manufactured by Nippon Aerosil Co., Ltd.

[0052] When the curable optical adhesive composition contains fumed silica, the amount is not particularly limited, but is preferably 0.5 to 10% by mass, more preferably 1 to 7% by mass, and more preferably 2 to 5% by mass, based on the entire curable optical resin composition.

[0053] 3. Curable optical adhesive composition The curable optical adhesive composition of the present invention is a composition that is applied to a substrate and cured, and comprises the above-mentioned curable optical resin composition and optionally the above-mentioned additive components.

[0054] <Manufacturing method> The curable optical adhesive composition may be prepared by any method that allows for the dispersion and mixing of the curable optical resin composition and the above-mentioned components. As a general method, the components are weighed, mixed and kneaded using a mixing machine, mixing roll (such as a three-roll mill), planetary mixer, etc., and degassed as necessary to obtain the curable optical adhesive composition.

[0055] <Curing method> The method for curing the curable optical adhesive composition of the present invention preferably includes a photocuring step of curing the composition by light irradiation and a thermocuring step of further curing by heating. By curing by light irradiation and then applying heat treatment, the curable optical resin composition is sufficiently cured, and the hardness of the cured product is improved.

[0056] In the photocuring process, the irradiated light preferably includes light in the wavelength range of 300 nm to 500 nm, and more preferably includes ultraviolet light with a wavelength of 400 nm or less (preferably 350 to 380 nm). The light source is not particularly limited, but examples include ultraviolet LEDs, blue LEDs, white LEDs, lasers, metal halide lamps, xenon lamps, and high-pressure or medium-pressure mercury lamps. The amount of light irradiated is not particularly limited, but the intensity at a wavelength of 365 nm is preferably 10 to 1000 mW / cm². 2 A suitable range is 100-800 mW / cm². 2 A more moderate degree is preferable. The duration of light exposure is not particularly limited, but for example, it is between 2 seconds and 5 minutes.

[0057] In the thermosetting process, the heating temperature is preferably 60°C to 150°C, more preferably 80°C to 125°C. The heating time is not particularly limited, but is preferably, for example, 10 minutes to 4 hours.

[0058] <Application> The curable optical adhesive composition of the present invention can be used in a variety of fields. In the field of optical equipment, it can be used as an adhesive for camera modules, LiDAR modules (light detection and ranging, detection and distance measurement using light (including lasers and infrared rays)), lens materials for still cameras, viewfinder prisms, target prisms, viewfinder covers, light receiving sensor parts, photographic lenses, projection lenses for projection televisions, etc. Examples of bonding locations in camera modules include between the image sensor (image sensor) such as CMOS or CCD and the substrate, between the cut filter and the substrate, between the substrate and the housing, between the housing and the cut filter, and between the housing and the lens unit. In other fields, it can be used in the automotive and transportation sector for bonding automotive switches, electrical components, etc.; in flat panel displays for sealing and bonding liquid crystal displays, organic electroluminescent displays, light-emitting diode displays, and field emission displays, as well as ink materials; in the recording sector for bonding video discs, CDs, DVDs, MDs, pickup lenses, hard disk peripherals (spindle motor components, magnetic head actuator components, etc.), Blu-ray discs, etc.; in the electronic materials sector for structural bonding and coating of electronic components; and in the optical components sector for sealing and bonding optical fiber materials around optical switches and optical connectors in optical communication systems, optical passive components, optical circuit components, and optoelectronic integrated circuits.

[0059] Examples of substrates to which the curable optical adhesive composition of the present invention can be used include glass, various metals, porous materials, resin films and plates, etc. Examples of the various metals include aluminum, nickel, iron, stainless steel, etc. Examples of the porous materials include ceramics. Examples of resins used as raw materials for the resin films and plates include polycarbonate, PPS, PBT, PA, LCP, FR4, FR5, etc.

[0060] In a preferred embodiment, the curable optical adhesive composition of the present invention is used for assembling a camera module. More specifically, the curable optical adhesive composition of the present invention is preferably used to bond a lens holder to a substrate on which an image sensor is fixed in the assembly of a camera module. In the above, the camera module is not particularly limited and is, for example, a small camera module used in smartphones, automotive cameras, etc. [Examples]

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0062] First, the following materials were prepared as raw materials.

[0063] [Table 2]

[0064] <Preparation of a curable optical adhesive composition> The materials in Table 1 were blended in the proportions shown in Table 3, and the mixture was kneaded and dispersed using a planetary mixer to prepare the curable optical adhesive compositions for each example and comparative example. The following evaluations were performed on each of the obtained curable optical adhesive compositions. The results are shown in Table 1.

[0065] <Elongation at break> A curable optical adhesive composition is applied to a release film, and a 365nm-UV-LED (500mW / cm²) is used to illuminate it. 2 After irradiating with ) for 5 seconds, the specimens were cured in a hot air circulating oven at 120°C for 60 minutes to prepare JIS Z1702 No.3 dumbbell test specimens (1 mm thick). The dumbbell test specimens were placed in an Instron "Autograph 5900R" (product name) and pulled at a speed of 10 mm / min at room temperature, and the elongation at fracture was recorded.

[0066] <Glass transition temperature (Tg)> A curable optical adhesive composition is applied to a release film, and a 365nm-UV-LED (500mW / cm²) is used to illuminate it. 2 After irradiating with ) for 5 seconds, a 1 mm thick test specimen was prepared by curing it in a hot air circulation oven at 120°C for 60 minutes. The test specimen was placed in a SII Nanotechnology 6100 dynamic viscoelasticity analyzer, and Tg was determined from the peak value of the loss tangent measured under the following conditions.

[0067] [Table 3]

[0068] [Table 4]

Claims

1. A curable optical adhesive composition comprising a curable optical resin composition containing a (meth)acryloyloxy group-containing (meth)acrylic polymer (A), a high glass transition temperature vinyl monomer (B), a rigid filler (C), and a polymerization initiator (D), A curable optical adhesive composition wherein the cured product of the curable optical resin composition is an optical resin having a glass transition temperature of 125°C or higher and an elongation of 3% or higher at room temperature.

2. The curable optical adhesive composition according to claim 1, wherein monomer (B) has a glass transition temperature of 80 to 260°C.

3. The curable optical adhesive composition according to claim 1, wherein the rigid filler (C) has a linear expansion coefficient of 20 ppm / °C or less.

4. The curable optical adhesive composition according to claim 1, wherein the mass ratio A / B of polymer (A) to monomer (B) is 0.3 to 3.

5. The curable optical adhesive composition according to claim 1, wherein the mass ratio (C / (A+B)) of the hard filler (C) to the total resin (A+B) is 1 to 3.

6. The curable optical adhesive composition according to claim 1, wherein the polymerization initiator (D) comprises a photopolymerization initiator (D1) and a thermal polymerization initiator (D2).

7. The curable optical adhesive composition according to claim 1, wherein polymer (A) has a number average molecular weight of 3,000 to 100,000.

8. The curable optical adhesive composition according to claim 1, wherein monomer (B) comprises at least one selected from the group consisting of isobornyl acrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, and combinations thereof.

Images