KR20130040683A - Optical assembly having a display panel and methods of making and disassembling same - Google Patents

Abstract

The optically clear adhesive layer comprises a liquid optically clear adhesive and thixotropic agent having a viscosity at a shear rate of 1 sec ⁻¹ of less than about 20 Pa · s. The optically transparent layer has a displacement creep when the haze is about 2% or less, a viscosity at a shear rate of 10 sec ⁻¹ is about 2 to about 30 Pa.s and a stress of 10 Pa is applied for about 2 minutes. (displacement creep) is less than about 0.2 radians and reaches a delta of 35 degrees after 80 microN · m of torque is applied at a frequency of 1 kHz immediately after approximately 100 microNm of torque is applied for about 60 seconds at a frequency of 1 kHz. Recovery time is about 60 seconds or less. The adhesive layer can be used to bond the display panel to the substantially transparent substrate in the optical assembly. The adhesive layer provides a cleavage strength between about 15 N / mm or less between the glass substrates so that the optical assembly can be disassembled with little or no damage to the display panel or substrate. Also disclosed are optical assemblies and methods of making optical assemblies. Optical assemblies can be used in optical devices such as handheld devices, televisions, computer monitors, laptop displays, or digital signs.

Description

Optical assembly having a display panel and a method for manufacturing and disassembling the same {OPTICAL ASSEMBLY HAVING A DISPLAY PANE AND

An optically clear adhesive layer is disclosed that can be used in an optical assembly. The optical assembly includes a display panel optically bonded to other optical components and can be used in the display device.

Optical bonding can be used to attach two optical elements together using an optical grade adhesive. In a display application, the optical junction may include optical elements such as a display panel, a glass plate, a touch panel, a diffuser, a rigid compensator, a heater, and a flexible film such as a polarizer. And a retarder. ≪ / RTI > The optical performance of the display can be improved by minimizing the number of internal reflective surfaces, and therefore it may be desirable to eliminate or at least minimize the number of air gaps between optical elements in the display.

In one embodiment, the optically clear adhesive layer comprises a liquid optically clear adhesive and thixotropic agent having a viscosity at a shear rate of 1 sec ⁻¹ of less than about 20 Pa · s. The optically clear adhesive layer has a haze of about 2% or less, a viscosity at a shear rate of 10 sec ⁻¹ of about 2 to about 30 Pa.s, and a displacement when a stress of 10 Pa is applied for about 2 minutes. The displacement creep is about 0.2 radians or less, and after a torque of about 1000 microNm for about 60 seconds at a frequency of 1 kHz, 80 microN · m of torque at 1 kHz is applied followed by a delta of 35 degrees. The recovery time until reaching is about 60 seconds or less.

In another embodiment, disclosed herein is an optical assembly comprising a display panel. The optical assembly includes a display panel; A substantially transparent substrate; And an adhesive layer disposed between the display panel and the substantially transparent substrate.

The optical assemblies disclosed herein can be used in optical devices, including, for example, handheld devices including displays, televisions, computer monitors, laptop displays, or digital signs.

In another embodiment, a method of making an optical assembly is disclosed.

These and other aspects of the invention are described in the detailed description below. In no event shall the above summary be construed as limiting the claimed subject matter, which is limited only by the claims disclosed herein.

The optical material may be used to fill the gap between the optical components or substrates of the optical assembly. An optical assembly comprising a display panel bonded to an optical substrate may be beneficial if the gap between the two is filled with an optical material that matches or nearly matches the refractive indices of the panel and the substrate. For example, inherent solar and ambient light reflections between the display panel and the outer cover sheet can be reduced. The color gamut and color contrast of the display panel may be improved under ambient conditions. Optical assemblies with filled gaps can also exhibit improved impact resistance compared to the same assemblies with air gaps.

Optical materials used to fill the gaps between optical components or substrates typically include adhesives and various types of cured polymeric compositions. However, these optical materials are not useful for manufacturing optical assemblies when it is desired to disassemble or rework the optical assemblies with little or no damage to the components later. These components require this reworkability feature for optical assemblies because the components tend to break down and are expensive. For example, if a flaw is observed during or after assembly or the cover sheet is damaged after sale, the cover sheet often needs to be removed from the display panel. It is desirable to rework the assembly by removing the cover sheet from the display panel with little or no damage to the components. As the size or area of available display panels continues to increase, reworkability becomes increasingly important.

Optical assemblies having large sizes or areas may be difficult to manufacture, especially if efficiency and stringent optical quality are required. The gap between the optical components can be filled by pouring or injecting the curable composition into the gap and then curing the composition to bond the components together. However, these compositions, which are generally used, have a long flow-out time, which contributes to the inefficient manufacturing method for large optical assemblies.

The optical assembly disclosed herein includes an adhesive layer and optical components, in particular a display panel and a substrate that is substantially light transmissive. The adhesive layer allows the assembly to be reworked with little or no damage to the components. The adhesive layer has a cleavage strength between about 15 N / mm or less, 10 N / mm or less, or so that reworkability can be obtained with little or no damage to the components. 6 N / mm or less. The total energy for the cleavage may be less than about 25 kg * mm over an area of 1 ″ × 1 ″ (2.5 cm × 2.5 cm).

The adhesive layer is suitable for optical applications. For example, the adhesive layer may have a transmittance of over 85% over a range of 460 to 720 nm. The adhesive layer may have a permeability of more than about 85% at 460 nm, greater than about 90% at 530 nm, and greater than about 90% at 670 nm. These transmissive properties provide uniform transmission of light over the visible region of the electromagnetic spectrum that is critical to maintaining the color point in a full color display.

The color portion of the transparency characteristic of the adhesive layer is further defined by its color coordinates indicated by the CIE L * a * b * transformation. For example, the b * component of the color should be less than about 1, more preferably less than about 0.5. This property of b * provides a low yellowing index, which is important for maintaining color points in a full color display.

The turbidity portion of the transparency properties of the adhesive layer was measured by a turbidimeter such as HazeGard Plus or Hunter Labs, available from Byk Gardner. It is further defined by the% turbidity value of the adhesive layer. For example, the% turbidity of the adhesive layer should be less than about 2%, more preferably less than about 1%. This haze characteristic provides low light scattering, which is important for maintaining output quality in full color displays.

For the reasons mentioned above, the adhesive layer preferably has a refractive index that matches or closely matches the refractive index of the display panel and / or the substantially transparent substrate. The refractive index of the adhesive can be controlled by appropriately selecting the adhesive components. For example, the refractive index can be increased by incorporating oligomers, diluent monomers, or the like, which contain a higher content of aromatic structure or incorporate sulfur or a halogen such as bromine. Conversely, the refractive index can be adjusted to lower the value by incorporating oligomers, diluent monomers, and the like, which contain higher contents of aliphatic structures. For example, the adhesive layer may have a refractive index of from about 1.4 to about 1.7.

The adhesive can be kept transparent by appropriately selecting adhesive components, including oligomers, diluent monomers, fillers, plasticizers, tackifying resins, photoinitiators, and any other components that contribute to the overall properties of the adhesive. In particular, the adhesive components must be compatible with each other and, unless the turbidity is desired, such as for diffusion adhesive applications, the adhesive components can be cured before or after curing to such an extent that the domain size and refractive index difference manifests light scattering and turbidity It should not be phase separated. In addition, the adhesive component should be free of particles that will be dissolved in the adhesive formulation and sufficiently large to scatter light, thereby contributing to turbidity. If such turbidity is required, such as in diffusion adhesive applications, this can be tolerated. In addition, various fillers, such as thixotropic materials, must be well dispersed so that they do not contribute to phase separation or light scattering, which can contribute to loss of light transmission and turbidity increase. Again, this is acceptable if such turbidity is required, such as in diffusion adhesive applications. These adhesive components should also not deteriorate the color characteristics of transparency, for example, by imparting color or increasing the b * or yellowing index of the adhesive layer.

The adhesive layer may comprise a display panel; A substantially transparent substrate; And an adhesive layer disposed between the display panel and the substantially transparent substrate. The adhesive layer may have any thickness. The specific thickness employed in the optical assembly can be determined by many factors, for example the design of the optical device in which the optical assembly is used may require a certain gap between the display panel and the substantially transparent substrate. The adhesive layer typically has a thickness of about 1 μm to about 5 mm, about 50 μm to about 1 mm, or about 50 μm to about 0.2 mm.

The adhesive layer can be prepared using a liquid optically clear adhesive, or a liquid composition in combination with a thixotropic agent, wherein the liquid composition has a viscosity suitable for efficiently preparing large optical assemblies. The large optical assembly may have an area of about 15 cm 2 to about 5 m 2 or about 15 cm 2 to about 1 m 2. For example, the liquid composition may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp, about 200 to about 500 cp, Or from about 500 to about 4000 cp, wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. Liquid compositions are suitable for use in various manufacturing methods.

The adhesive layer has a viscosity of 30 Pa · s or less, about 2 to about 30 Pa · s, and in particular about 5 to about 20 Pa · when the adhesive layer has a shear rate of 1 to 10 sec ⁻¹ when combined with a thixotropic agent and any liquid, optically clear adhesive having a viscosity to be s. This range from 1 to 10 sec ⁻¹ governs the ability of the adhesive layer to flow under the squeegee used during stencil printing, for example, so that the adhesive layer does not adhere to the squeegee at higher squeegee speeds. do. In addition, this viscosity is low enough to fill the cavity of the stencil with the fluid without the flow of bubbles or insufficient flow to fill the cavity completely with the liquid adhesive fluid. The range of 1 to 10 sec ⁻¹ governs the ability of the adhesive layer to flow under the squeegee at lower rates. At 1 sec ⁻¹ , the adhesive layer had a viscosity of about 18 to about 140 Pa · s. At 0.01 sec ⁻¹ , the adhesive layer has a viscosity of at least 700 Pa · s, at least 2,000 Pa · s, and preferably at least 10,000 Pa · s. The range at 0.01 sec ⁻¹ defines when the adhesive layer has non-sag characteristics.

In one embodiment, the liquid optically clear adhesive used for the adhesive layer has a viscosity at a shear rate of 1 to 10 sec ⁻¹ or less about 20 Pa · s. In particular, liquid optically clear adhesives have a viscosity at shear rates of 1 to 10 sec ⁻¹ or less, and more particularly about 5 Pa · s or less. Within these ranges, the viscosity of the adhesive layer will be in the appropriate range when the thixotropic agent is added.

In one embodiment, the adhesive layer comprises a reaction product of a multifunctional (meth) acrylate oligomer and a reactive diluent comprising a monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. of about 4 to about 20 cp; And plasticizers. In general, (meth) acrylate refers to both acrylate and methacrylate functional groups.

The multifunctional (meth) acrylate oligomer may comprise any one or more of a multifunctional urethane (meth) acrylate oligomer, a multifunctional polyester (meth) acrylate oligomer, and a multifunctional polyether (meth) acrylate oligomer have. The multifunctional (meth) acrylate oligomer may comprise at least two (meth) acrylate groups, for example two to four (meth) acrylate groups, which participate in the polymerization during cure. The adhesive layer may comprise about 15 to about 50 weight percent, about 20 to about 60 weight percent, or about 20 to about 45 weight percent multifunctional (meth) acrylate oligomer. The amount used, as well as the specific multifunctional (meth) acrylate oligomer used, may depend on various factors. For example, certain oligomers and / or amounts thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp. , About 200 to about 500 cp, or about 500 to about 4000 cp, wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. In another example, the particular oligomer and / or amount thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp, and the resulting adhesive layer can be selected to have a Shore A hardness of less than about 30, less than about 20, or less than about 10, wherein the viscosity Is measured at 25 ° C. and 1 sec ⁻¹ for the composition. For another example, certain oligomers and / or amounts thereof have an adhesive composition having a viscosity at 25 ° C. and a shear rate of 1 sec ⁻¹ and 18,000 cp to 140,000 cp for the composition, at 25 ° C. and a shear rate of 0.01 sec ⁻¹ . Can be chosen to be a liquid composition having a viscosity of 700,000 cp to 4,200,000 cp relative to the composition.

(Meth) acrylate oligomer having at least two (meth) acrylate groups, for example, two to four (meth) acrylate groups, which participate in polymerization during curing. The polyfunctional (meth) Lt; / RTI > oligomers. Generally, these oligomers include reaction products that are produced by reacting a polyol with a polyfunctional isocyanate followed by termination with a hydroxy-functionalized (meth) acrylate. For example, the polyfunctional urethane (meth) acrylate oligomer may be an aliphatic poly (meth) acrylate oligomer prepared from the condensation of dicarboxylic acids such as adipic acid or maleic acid with aliphatic diols such as diethylene glycol or 1,6- Esters or polyether polyols. In one embodiment, the polyester polyol comprises adipic acid and diethylene glycol. The multifunctional isocyanate may include methylene dicyclohexyl isocyanate or 1,6-hexamethylene diisocyanate. Hydroxy-functionalized (meth) acrylates include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate , Or polyethylene glycol (meth) acrylate. In one embodiment, the multifunctional urethane (meth) acrylate oligomer comprises the reaction product of a polyester polyol, methylene dicyclohexylisocyanate, and hydroxyethyl acrylate.

Useful multifunctional urethane (meth) acrylate oligomers include commercially available products. For example, multifunctional aliphatic urethane (meth) acrylate oligomers are available from urethane diacrylates CN9018, CN3108 and CN3211, Aurora, Illinois, available from Sartomer, Co., Exton, Pa. GENOMER 4188 / EHA (a blend of Genomer 4188 and 2-ethylhexyl acrylate), Genomer 4188 / M22 (genomer 4188 and Genomer 1122 monomers available from Rahn USA Corp.) Blends), Genomer 4256 and Genomer 4269 / M22 (blend of Genomer 4269 and Genomer 1122 monomers), U-Pica 8966, available from Japan U-Pica Corp. 8967, 8967A, and combinations thereof, and polyether urethane diacrylates BR-3042, BR-3641AA, BR-3741AB available from Bomar Specialties Co., Torrington, Conn. And BR-344.

In general, the multifunctional urethane (meth) acrylate oligomer may be used in any amount depending on the desired properties of the adhesive layer as well as other components used to form the adhesive layer. The adhesive layer may comprise about 15 to about 50 weight percent, about 20 to about 60 weight percent, or about 20 to about 45 weight percent multifunctional urethane (meth) acrylate oligomer.

The multifunctional (meth) acrylate oligomer may comprise a multifunctional polyester (meth) acrylate oligomer. Useful multifunctional polyester acrylate oligomers include commercially available products. For example, the multifunctional polyester acrylate may include BE-211 available from Bomar Specialties Company and CN2255 available from Sartomer Company.

The multifunctional (meth) acrylate oligomer may comprise a multifunctional polyether (meth) acrylate oligomer. Useful multifunctional polyether acrylate oligomers include commercially available products. For example, the multifunctional polyether acrylate may comprise Genomer 3414 available from Lan USA Corporation.

The reaction product forming the adhesive layer is formed from the reaction diluent. The reaction diluent comprises a monofunctional (meth) acrylate monomer having a viscosity at 25 ° C. of about 4 to about 20 cp. The reactive diluent may comprise more than one monomer, for example 2 to 5 different monomers. Examples of these monomers include isobornyl acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, alkoxylated tetrahydrofurfuryl acrylate, alkoxylated methacrylate, Tetrahydrofurfuryl methacrylate, and mixtures thereof. For example, the reactive diluent may include tetrahydrofurfuryl (meth) acrylate and isobornyl (meth) acrylate. In another example, the reactive diluent may comprise alkoxylated tetrahydrofurfuryl acrylate and isobornyl acrylate.

In general, the reactive diluent may be used in any amount depending on the desired properties of the adhesive layer, as well as other components used to form the adhesive layer. The adhesive layer may comprise about 15 to about 50 weight percent, about 30 to about 60 weight percent, or about 40 to about 60 weight percent reactive diluent relative to the total weight of the adhesive layer.

The particular reactive diluent used and the amount (s) of monomer (s) used may depend on a variety of factors. For example, certain monomer (s) and amount (s) thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp, wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. In another example, the specific monomer (s) and amount (s) thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, Selected to have a liquid composition of about 200 to about 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp and the resulting adhesive layer to have a Shore A hardness of less than about 30, less than about 20, or less than about 10 Wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. As another example, the specific diluent and / or amount thereof may be such that the adhesive composition has a viscosity at 25 ° C. and a shear rate of 1 sec ⁻¹ for the composition from 18,000 cp to 140,000 cp, at 25 ° C. and a shear rate of 0.01 sec ⁻¹ Can be chosen to be a liquid composition having a viscosity of 700,000 cp to 4,200,000 cp relative to the composition.

The adhesive layer includes a plasticizer that increases its ductility and flexibility. Plasticizers are well known and typically do not participate in the polymerization of (meth) acrylate groups. The plasticizer may comprise more than one plasticizer material. The plasticizer may comprise an oil. Suitable oils include vegetable oils, mineral oils and soybean oil. The adhesive layer may comprise greater than 5 weight percent to about 20 weight percent, or greater than 5 weight percent to about 15 weight percent plasticizer. The amount used as well as the particular plasticizer used may depend on a variety of factors. For example, certain plasticizers and / or amounts thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp. , About 200 to about 500 cp, or about 500 to about 4000 cp, wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. In another example, certain plasticizers and / or amount (s) may be selected so that the adhesive composition has a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp, and the resulting adhesive layer is selected to have a Shore A hardness of less than about 30, less than about 20, or less than about 10. Wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. For another example, certain plasticizers and / or amounts thereof may have a viscosity of 18,000 cp to 140,000 cp for the composition at 25 ° C. and a shear rate of 1 sec ⁻¹ , at 25 ° C. and a shear rate of 0.01 sec ⁻¹ . Can be chosen to be a liquid composition having a viscosity of 700,000 cp to 4,200,000 cp relative to the composition.

The reaction product forming the adhesive layer may further comprise a monofunctional (meth) acrylate monomer having an alkylene oxide functional group. Such monofunctional (meth) acrylate monomers having an alkylene oxide functionality may comprise more than one monomer. Alkylene functional groups include ethylene glycol and propylene glycol. The glycol functionality is comprised of units where the monomers may anywhere from 1 to 10 alkylene oxide units, from 1 to 8 alkylene oxide units, or from 4 to 6 alkylene oxide units. Monofunctional (meth) acrylate monomers having alkylene oxide functional groups may include propylene glycol monoacrylates available as BISOMER PPA6 from Cognis Ltd. This monomer has 6 propylene glycol units. Monofunctional (meth) acrylate monomers having alkylene oxide functional groups can include ethylene glycol monomethacrylate, available as Bisomer MPEG350MA from Cognis Limited. This monomer has an average of 7.5 ethylene glycol units.

The adhesive layer may comprise about 5 to about 30 weight percent, or about 10 to about 20 weight percent monofunctional (meth) acrylate monomers having alkylene oxide functionality. The particular monomers used as well as the amount used can depend on a variety of factors. For example, certain monomers and / or amounts thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp. , About 200 to about 500 cp, or about 500 to about 4000 cp, wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. In another example, the specific monomers and / or amounts thereof may be such that the adhesive composition has a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp, and the resulting adhesive layer can be selected such that the Shore A hardness is less than about 30, less than about 20, or less than about 10. Viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. For another example, certain monomers and / or amounts thereof may have a viscosity of 18,000 cp to 140,000 cp relative to the composition at 25 ° C. and a shear rate of 1 sec ⁻¹ , at 25 ° C. and a shear rate of 0.01 sec ⁻¹ . Can be chosen to be a liquid composition having a viscosity of 700,000 cp to 4,200,000 cp relative to the composition.

The adhesive layer has little or no tackifier as described above. Tackifiers are typically used to increase the tackiness of the adhesive. The amount used as well as the particular tackifier used may depend on a variety of factors. The tackifier and / or amount thereof may be selected such that the adhesive layer has a cleavage strength between the glass substrates of about 15 N / mm or less, 10 N / mm or less, or 6 N / mm or less. For example, certain tackifiers and / or amounts thereof may have a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to about It may be selected to be a liquid composition that is 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp, wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. In another example, the specific tackifier and / or amount thereof may be determined such that the adhesive composition has a viscosity of about 100 to 140,000 cp, about 100 to about 10,000 cp, about 100 to about 5000 cp, about 100 to about 1000 cp, about 200 to Wherein the liquid composition is about 700 cp, about 200 to about 500 cp, or about 500 to about 4000 cp and the resulting adhesive layer is selected to have a Shore A hardness of less than about 30, less than about 20, or less than about 10. Wherein the viscosity is measured at 25 ° C. and 1 sec ⁻¹ for the composition. For another example, certain tackifiers and / or amounts thereof may have a viscosity at 25 ° C. and a shear rate of 1 sec ⁻¹ for the adhesive composition at 18,000 cp to 140,000 cp for the composition, 25 ° C. and a shear rate of 0.01 sec ⁻ The viscosity at ¹ can be selected to be a liquid composition with a composition between 700,000 cp and 4,200,000 cp.

The adhesive layer can comprise about 15 to about 50 weight percent of a multifunctional (meth) acrylate oligomer and about 15 to about 50 weight percent of a reactive diluent; And from greater than 5 weight percent to about 25 weight percent of a plasticizer. The reaction product may further comprise monofunctional (meth) acrylate monomers having about 10 to about 20 weight percent alkylene oxide functional groups. This adhesive layer may comprise a glass-to-glass cleavage force of less than about 15 N / mm, less than about 10 N / mm, or less than about 6 N / mm.

The adhesive layer may comprise a reaction product of about 20 to about 60 weight percent multifunctional (meth) acrylate oligomer with about 30 to about 60 weight percent reactive diluent; And from greater than 5 weight percent to about 25 weight percent of a plasticizer. The reaction product may further comprise monofunctional (meth) acrylate monomers having about 10 to about 20 weight percent alkylene oxide functional groups. This adhesive layer may comprise a glass-to-glass cleavage force of less than about 15 N / mm, less than about 10 N / mm, or less than about 6 N / mm.

The adhesive layer may comprise about 25 to about 45 weight percent of the multifunctional (meth) acrylate oligomer and about 40 to about 60 weight percent of the reactive diluent; And from greater than 5 weight percent to about 15 weight percent of a plasticizer. The reaction product may further comprise monofunctional (meth) acrylate monomers having about 10 to about 20 weight percent alkylene oxide functional groups. The adhesive layer may comprise about 20 to about 50 weight percent of a multifunctional urethane (meth) acrylate oligomer and about 30 to about 60 weight percent of a reactive diluent; And from greater than 5 weight percent to about 25 weight percent of a plasticizer. The reaction product may further comprise monofunctional (meth) acrylate monomers having about 10 to about 20 weight percent alkylene oxide functional groups. The adhesive layer may comprise about 25 to about 45 weight percent of a multifunctional urethane (meth) acrylate oligomer and about 40 to about 60 weight percent of a reactive diluent; And from greater than 5 weight percent to about 15 weight percent of a plasticizer. The reaction product may further comprise monofunctional (meth) acrylate monomers having about 10 to about 20 weight percent alkylene oxide functional groups. The adhesive layer may comprise about 30 to about 60 weight percent of a multifunctional urethane (meth) acrylate oligomer and about 20 to about 30 weight percent of a reactive diluent; And greater than 5 wt% to about 10 wt% plasticizer; Monofunctional (meth) acrylate monomers having about 5 to about 10 weight percent of alkylene oxide functionality; And from about 2 to about 10 weight percent of dry silica.

The optical assembly includes a display panel; A substantially transparent substrate; And an adhesive layer disposed between the display panel and the substantially transparent substrate, wherein the adhesive layer is a monofunctional (meth) having a polyfunctional rubber-based (meth) acrylate oligomer and pendant alkyl groups of 4 to 20 carbon atoms. Reaction products of acrylate monomers; And liquid rubbers.

The multifunctional rubber-based (meth) acrylate oligomer is a multifunctional (meth) comprising a multifunctional polybutadiene (meth) acrylate oligomer, a multifunctional isoprene (meth) acrylate oligomer, and a copolymer of butadiene and isoprene At least one of the acrylate oligomers. The multifunctional rubber-based (meth) acrylate oligomer may comprise a multifunctional polybutadiene (meth) acrylate oligomer. Monofunctional (meth) acrylates having pendant alkyl groups of 4 to 20 carbon atoms may include pendant groups having 8 to 20 carbon atoms. The liquid rubber may comprise liquid isoprene.

Useful multifunctional polybutadiene (meth) acrylate oligomers include difunctional polybutadiene (meth) acrylate oligomer CN307 available from Sartomer Company. Useful multifunctional polyisoprene (meth) acrylate oligomers include methacrylated isoprene oligomers UC-102 and UC-203 available from Kuraray America, Inc.

Useful monofunctional (meth) acrylate monomers having pendant alkyl groups of 4 to 20 carbon atoms include 2-ethylhexyl acrylate, lauryl acrylate, isodecyl acrylate, and stearyl acrylate.

Liquid rubbers include LIR-30 liquid isoprene rubber and LIR-390 liquid butadiene / isoprene copolymer rubbers available from Kuraray, Inc., and RICON 130 liquid polybutadiene rubbers, available from Sartomer Company, Inc. It may include.

The adhesive layer may further comprise a plasticizer as described above.

The adhesive layer comprises about 20 to about 60 weight percent multifunctional rubber-based (meth) acrylate oligomer and about 20 to about 60 weight percent monofunctional (meth) acrylate monomer having from 4 to 20 carbon atoms pendant alkyl groups. Reaction product; And greater than 5 wt% to about 25 wt% liquid rubber.

The adhesive layer comprises about 20 to about 50 weight percent multifunctional rubber-based (meth) acrylate oligomer and about 20 to about 50 weight percent monofunctional (meth) acrylate monomers having 4 to 20 carbon atoms pendant alkyl groups. Reaction product; And greater than 5 wt% to about 25 wt% liquid rubber.

The adhesive layer contains little or no tackifier as described above.

The adhesive layer may comprise a tackifier. Tackifiers are well known and are used to increase the tack or other properties of the adhesive. While there are many different types of tackifiers, almost all tackifiers include rosin resins derived from wood rosin, gum rosin or tall oil rosin; Hydrocarbon resins prepared from petroleum based feedstocks; Or certain may be classified as terpene resins derived from terpene feedstocks of fruit or wood. The adhesive layer can include, for example, 0.01 to about 20 weight percent, 0.01 to about 15 weight percent, or 0.01 to about 10 weight percent tackifier. The adhesive layer may be substantially free of tackifiers, for example, including from 0.01 to about 5% by weight or from about 0.01 to about 0.5% by weight relative to the total weight of the adhesive layer. The adhesive layer may be free of tackifiers.

The adhesive layer may be flexible, for example the adhesive layer may have a Shore A hardness of less than about 30, less than about 20, or less than about 10.

The adhesive layer may exhibit little or no shrinkage, whatever amounts are allowed, for example less than about 5%.

In other embodiments, the adhesive may be a silicone substrate. For example, the adhesive may use an addition curing chemistry between the hydrosilicon functional silicon and the vinyl or ally functional silicone. Addition cure silicones are well known in the art, and they often incorporate platinum based catalysts that can be activated by heat or UV irradiation. Likewise, a bicomponent silicone liquid adhesive or gel forming material can be used as the substrate for such thixotropic printable materials. These types of silicon may require heat to rely on condensation chemistry and accelerate the curing mechanism.

In general, the adhesive layer may include metal oxide particles (as described below), for example, to adjust the refractive index of the adhesive layer or the viscosity of the liquid adhesive composition. Virtually transparent metal oxide particles can be used. For example, a 1 mm thick disk of metal oxide particles in an adhesive layer can absorb less than about 15% of the light incident on the disk. Examples of metal oxide particles include clays, Al ₂ O _3, ZrO _2, TiO ₂ , V ₂ O ₅ , ZnO, SnO ₂ , ZnS, SiO ₂ , and mixtures thereof, as well as other sufficiently transparent non-oxide ceramic materials. . Metal oxide particles may be surface treated to improve dispersibility in the adhesive layer and in the composition coating the layer. Examples of surface treatment chemicals include silanes, siloxanes, carboxylic acids, phosphonic acids, zirconates, titanates, and the like. Techniques for applying such surface treatment chemicals are known. Organic fillers such as cellulose, castor oil wax and polyamide-containing fillers can also be used.

In some embodiments, the adhesive layer comprises dry silica. Suitable dry silicas include AEROSIL 200; And Aerosil R805 (both available from Evonik Industries); CAB-O-SIL TS 610; And Cap-O-Sil T 5720 (both available from Cabot Corp.), and HDK H2ORH (available from Wacker Chemie AG).

In some embodiments, the adhesive layer comprises dry aluminum oxide, such as AEROXIDE ALU 130 (available from Evonik, Parsippany, NJ).

In some embodiments, the adhesive layer comprises clay, for example GARAMITE 1958 (available from Southern Clay Products).

The metal oxide particles are in an amount necessary to produce the desired effect, for example about 2 to about 10 weight percent, about 3.5 to about 7 weight percent, about 10 to about 85 weight percent, or based on the total weight of the adhesive layer, or It may be used in an amount of about 40 to about 85% by weight. The metal oxide particles can only be added to such an extent that it does not add undesirable color, turbidity or transparency properties. Generally, the particles may have an average particle size of about 1 nm to about 100 nm.

In some embodiments, the liquid optically clear adhesive includes a non-reactive oligomeric rheology modifier. While not wishing to be bound by theory, non-reactive oligomeric rheology modulators form viscosity at low shear rates through hydrogen bonding or other self-association mechanisms. Examples of suitable non-reactive oligomeric rheology modifiers include polyhydroxycarboxylic acid amides (e.g., BYK 405 available from Beyk-Chemie GmbH, Bezel, Germany), polyhydroxycarbide Acid esters (e.g., BYK R-606 available from Beike-Kemi Gembeh, Bezel, Germany), modified urea (e.g., from King Industries, Norwalk, CT) DISPARLON 6100, DISPARLON 6200 or DISPARLON 6500 or BYK 410 from Bewaikei-Kemi Gembeh, Bezel, Germany, metal sulfonates (e.g., furnace, Connecticut, USA) K-STAY 501 from King Industries, Work Materials, or Lubrizol Advanced Materials, Cleveland, Ohio, USA. IRCOGEL 903), acrylated oligoamines (e.g., Genomer 5275 from Lan U. Corporation, Aurora, Illinois, USA), polyacrylic acid (e.g., Lubrizol Advanced, Cleveland, Ohio) CARBOPOL 1620 of Material Materials Rotor, modified urethanes (eg, K-stay 740 from King Industries, Norwalk, CT), or polyamides. In some embodiments, the non-reactive oligomeric rheology modifier is selected to be compatible and compatible with the optically clear adhesive to limit phase separation and minimize turbidity.

In some embodiments, the adhesive layer can be formed from a thixotropic liquid optically clear adhesive. As used herein, the composition is intended to mean that the composition is shear thin, i. E. When the composition is subjected to shear stress over a given period of time, the viscosity is reduced and then the shear stress is reduced or eliminated, Or partial recovery occurs, it is believed to be ubiquitous. Such adhesives exhibit little or no flow under zero or near zero stress conditions. The advantage of the thixotropic property is that the adhesive can be easily dispensed by processes such as needle dispensing due to the rapid decrease in viscosity under low shear rate conditions. The main advantage of the back flushing behavior over simply high viscosity is that the high viscosity adhesive is difficult to dispense and difficult to flow during application. The adhesive composition can render the particles thixotropic by adding them to the composition. In some embodiments, dry silica is added in an amount of about 2 to about 10 weight percent, or about 3.5 to about 7 weight percent to impart thixotropic properties to the liquid adhesive.

In some embodiments, any liquid, optically transparent, having a viscosity at 1 to 10 sec ⁻¹ shear rate of 30 Pa · s or less, about 2 to about 30 Pa · s, and especially about 5 to about 20 Pa · s The adhesive can be combined with a thixotropic agent to form a thixotropic liquid optically clear adhesive suitable for stencil printing or screen printing. The efficiency and optical properties of the thixotropic agent depend on the composition of the liquid optically clear adhesive and its interaction with the thixotropic agent. For example, in the case of associative thixotropic agents or hydrophilic silica, the presence of highly polar monomers such as acrylic acid, acid or hydroxyl containing monomers or oligomers may interfere with thixotropic or optical performance.

In some embodiments, the viscosity of the liquid optically clear adhesive can be controlled at two or more different shear rates. In one embodiment, the adhesive layer has a viscosity at 25 ° C. and a shear rate of 10 sec ⁻¹ of about 2 to about 30 Pa · s, and particularly about 5 to about 20 Pa · s. In one embodiment, the adhesive layer has a viscosity at about 25 ° C. and a shear rate of 0.01 sec ⁻¹⁰ of about 700 to about 10,000 Pa · s, and particularly about 1,000 to about 8,000 Pa · s. In one embodiment, the adhesive layer has a viscosity at 25 ° C. and a shear rate of 1 sec ⁻¹ of about 18 Pa · s to about 140 Pa · s, and in particular about 30 Pa · s to about 100 Pa · s.

In some embodiments, the adhesive layer has a displacement creep of about 0.2 radians or less when a stress of 10 Pa is applied to the adhesive for 2 minutes. In particular, liquid optically clear adhesives have a displacement creep of about 0.1 radians or less when a 10 Pa stress is applied to the adhesive for 2 minutes. Generally, displacement creep is measured by using an AR2000 Rheometer manufactured by TA Instruments and a 40 mm diameter x 1 ° cone at 25 ^{° C.} , the cone when a 10 Pa stress is applied to the adhesive. It is defined as the rotation angle of. Displacement creep is associated with the ability of the thixotropic adhesive layer to resist flow or sag under very low stress conditions such as gravity and surface tension.

In some embodiments, liquid optically clear adhesives have a delta of 45 degrees or less, particularly 42 degrees or less, especially 35 degrees or less, when torque of 80 microN · m is applied at a frequency of 1 Hz in conical and plate flow meters. And more particularly 30 degrees or less. Delta is the phase delay between stress and strain when the vibrational force (stress) is applied to the material and the resulting displacement (strain) is measured. The delta is set in degrees. Delta is associated with the "solid behavior or non-sag characteristics of the thixotropic adhesive layer at very low vibrational stresses.

The adhesive layer also has the ability to recover its non-sag structure within a short time after passing under equipment such as squeegee in stencil printing applications. In one embodiment, the adhesive layer immediately after applying about 1000 microN · m of torque for about 60 seconds at a frequency of 1 Hz until reaching 35 degrees delta after applying 80 microN · m of torque at a frequency of 1 Hz The recovery time of is less than about 60 seconds, in particular less than about 30 seconds, and more particularly less than about 10 seconds.

When cured with UV-radiation, photoinitiators can be used in the liquid composition. Photoinitiators for free radical curing include organic peroxides, azo compounds, quinines, nitro compounds, acyl halides, hydrazones, mercapto compounds, pyrylium compounds, imidazoles, chlorotriazines, benzoin, benzoin alkyl ethers, And the like. For example, the adhesive composition may be ethyl-2,4,6-trimethylbenzoylphenylphosphinate or Ciba Specialty Chemicals available as LUCIRIN TPO-L from BASF Corp. ) 1-hydroxycyclohexyl phenyl ketone available as IRGACURE 184. Photoinitiators are often used at a concentration of about 0.1 to 10 weight percent, or 0.1 to 5 weight percent, relative to the weight of oligomer and monomer material of the polymerizable composition.

The liquid composition and the adhesive layer may optionally include one or more additives such as chain transfer agents, antioxidants, stabilizers, flame retardants, viscosity modifiers, antifoams, antistatic agents and wetting agents. If color is required for the optical adhesive, colorants such as dyes and pigments, fluorescent dyes and pigments, phosphorescent dyes and pigments may be used.

The adhesive layer described above is formed by curing the adhesive composition or liquid composition. Any form of electromagnetic radiation can be used, for example the liquid composition can be cured using UV-radiation and / or heat. Electron beam radiation may also be used. The liquid composition described above is said to be cured using actinic radiation, ie radiation which leads to the generation of photochemical activity. For example, actinic radiation may comprise radiation of about 250 to about 700 nm. Sources of actinic radiation include tungsten halogen lamps, xenon and mercury arc lamps, incandescent lamps, germicidal lamps, fluorescent lamps, lasers and light emitting diodes. UV-radiation can be supplied using high intensity continuous light emission systems such as those available from Fusion UV Systems.

In some embodiments, actinic radiation may be applied to the layer of the liquid composition such that the liquid composition is partially polymerized. The liquid composition can be disposed between the display panel and the substantially transparent substrate and then partially polymerized. The liquid composition may be disposed on the display panel or substantially transparent substrate and partially polymerized, and then the other of the display panel and the substrate may be disposed on the partially polymerized layer.

In some embodiments, actinic radiation may be applied to the layer of the liquid composition such that the liquid composition is fully or nearly fully polymerized. The liquid composition can be disposed between the display panel and the substantially transparent substrate and then fully or nearly fully polymerized. The liquid composition may be disposed on a display panel or substantially transparent substrate and completely or almost completely polymerized, and then the other of the display panel and the substrate may be disposed on the polymerized layer.

In the assembly process, it is generally desirable to have a layer of a substantially uniform liquid composition. Keep the two components in place securely. If necessary, uniform pressure can be applied over the entire top of the assembly. If desired, the thickness of the layer can be controlled by gaskets, standoffs, shims and / or spacers used to keep the components at a fixed distance from each other. Masking may be required to protect the components from overflow. The captured pocket of air may be prevented or removed by vacuum or other means. Then, an adhesive layer can be formed by applying radiation.

The optical assembly may be manufactured by creating an air gap or cell between two components and then placing the liquid composition into the cell. One example of such a method is described in US Pat. No. 6,361,389 B1 (Hogue et al.) And includes attaching the components together at the peripheral edge such that the seal along the peripheral edge creates an air gap or cell. Attachment can be performed using any type of adhesive, for example, bonding tapes such as double-sided pressure sensitive adhesive tape, gaskets, RTV seals, and the like, so long as the adhesive does not interfere with the reworkability described above. The liquid composition is then poured into the cell through the opening at the peripheral edge. Alternatively, the liquid composition is injected into the cell, perhaps using some pressurized injection means, such as a syringe. As the cell is charged, another opening is required to allow air to escape. Exhaust means such as vacuum may be used to facilitate this process. Subsequently, actinic radiation or heat may be applied as described above to form the adhesive layer.

Optical assemblies can be made using assembly fixtures such as those described in US Pat. No. 5,867,241 (Sampica et al.). In this method, a fastener is provided that includes a flat plate into which the pins are pushed in. These pins are positioned in a predetermined shape to produce a pin field corresponding to the dimensions of the display panel and the dimensions of the components to be attached to the display panel. These pins are arranged such that each of the four corners of the display panel and other components is held in place by the pins as the display panel and other components fall into the pin area. This fixture aids in the assembly and alignment of the components of the optical assembly by proper control of the alignment tolerance. Further embodiments of this assembly method are described in Sampica et al. U. S. Patent No. 6,388, 724 B1 (Campbell et al.) Describes how standoffs, shims, and / or spacers can be used to keep components at a fixed distance from each other.

In another embodiment, thixotropic liquid optically clear adhesives may be applied to one or both of the components for assembly by stencil printing. Stencil printing is a method of transferring a pattern by brushing, spraying, or compressing an adhesive through an open area of a stencil cut or fabricated from thin metal, plastic or cardboard. Pressing is desirable to obtain an adhesive liquid coating of smooth and uniform thickness. The stencil preferably has only the outer boundary, or perimeter, formed by the metal, plastic or cardboard, leaving the interior of the stencil completely free of metal, plastic or cardboard. In order to reinforce the stencil or to prevent sagging of the squeegee in the interior portion of the stencil, optionally a rib, or narrow length metal, plastic or cardboard, may span the stencil interior from one side to the other. The stencil material is preferably metal.

The optical assembly disclosed herein may include additional components typically in the form of a layer. For example, a heating source comprising a layer of indium tin oxide or other suitable material may be disposed in one of the components. Further components are described, for example, in US Patent Application Publication No. 2008/0007675 A1 (Sanelle et al.).

The display panel may comprise any type of panel, for example a liquid crystal display panel. Liquid crystal display panels are well known and typically comprise a liquid crystal material disposed between two substantially transparent substrates, such as glass or polymer substrates. As used herein, “virtually transparent” refers to a substrate suitable for optical applications, for example, having a transmittance of at least 85% over the range of 460-720 nm. The optical substrate can have a transmittance per mm of thickness greater than about 85% at 460 nm, greater than about 90% at 530 nm, and greater than about 90% at 670 nm. On the inner surface of the substantially transparent substrate, there is a transparent electrically conductive material that functions as an electrode. In some cases, on the outer surface of the substantially transparent substrate there is a polarizing film that essentially passes only one polarization state of light. When a voltage is selectively applied across this electrode, the liquid crystal material is redirected to change the polarization state of the light to produce an image. The liquid crystal display panel may also include a liquid crystal material disposed between a thin film transistor array panel having a plurality of thin film transistors arranged in a matrix pattern and a common electrode panel having a common electrode.

The display panel may include a plasma display panel. Plasma display panels are well known and typically include an inert mixture of rare gases, such as neon and xenon, disposed in small cells located between two glass panels. Control circuit charge electrodes in the panel ionize these gases and form a plasma, which then excites phosphors to emit light.

The display panel may include an organic electroluminescent panel. These panels are essentially layers of organic material disposed between two glass panels. The organic material may include an organic light emitting diode (OLED) or a polymer light emitting diode (PLED). These panels are well known.

The display panel may include an electrophoretic display. Electrophoretic displays are well known and are used in display technologies, typically referred to as electronic paper or e-paper. The electrophoretic display comprises a liquid filled material disposed between two transparent electrode panels. The liquid filled material can include nanoparticles, dyes, and fillers suspended in non-polar hydrocarbons, or microcapsules filled with electrically charged particles suspended in a hydrocarbon material. The microcapsules may also be suspended in a layer of liquid polymer.

Substantially transparent substrates used in optical assemblies may include various types and materials. Virtually transparent substrates are suitable for optical applications and typically have a transmittance of at least 85% over the range of 460-720 nm. In fact, the transparent substrate may have a transmission per millimeter of thickness greater than about 85% at 460 nm, greater than about 90% at 530 nm, and greater than about 90% at 670 nm.

The substantially transparent substrate may comprise glass or a polymer. Useful glasses include borosilicates, soda lime, and other glasses suitable for use in display applications as protective covers. One particular glass that can be used includes EAGLE XG and JADE glass substrates available from Corning Inc. Useful polymers include polyester films such as polyethylene terephthalate, polycarbonate films or plates, acrylic films such as polymethylmethacrylate films, and cycloolefin polymer films such as Zeon Chemicals LP. ZEONOX and ZEONOR available from. The substantially transparent substrate preferably has a refractive index close to that of the display panel and / or the adhesive layer; For example, about 1.4 to about 1.7. Virtually transparent substrates are typically about 0.5 to about 5 mm thick.

The substantially transparent substrate may comprise a touch screen. Touch screens are well known and generally comprise a transparent conductive layer disposed between two substantially transparent substrates. For example, the touch screen may comprise indium tin oxide disposed between the glass substrate and the polymer substrate.

The optical assemblies disclosed herein may be used in a variety of optical devices, including, but not limited to, hand held devices such as telephones, televisions, computer monitors, projectors, and signage. The optical device may include a backlight.

Example

The materials used in the examples below are described in Table 1.

[Table 1]

Preparation of Liquid Optically Clear Adhesives

Compositions for Comparative Examples 1 and 2 (C1 and C2) and Examples 1 to 9 (Ex1 to Ex9) comprising a liquid optically clear adhesive (loca) were prepared according to Table 2. For a given composition, the Roca components are charged to Max 200 (about 100 cm 3), a black mixing vessel from FlackTek Inc., Landrum, SC, USA. Mixing was performed at 2200 rpm for 4 minutes using a Hauschild Speedmixer ™ DAC 600 FV from.

[Table 2]

Hardness measurement

Sample puck was prepared by filling four cavity molds with each of the aforementioned loca. The cavity size cut out from the aluminum plate was 2.54 cm diameter x 0.64 cm thickness (1 "diameter x 0.25" thickness). The mold included an aluminum plate with three components: a glass base, a polyethylene terephthalate release liner, and a cavity. Prior to filling with the loca, three elements of the mold were clamped together: the glass base, the release liner, and the aluminum cavity. UV by passing filled molds through Model F300S and Model LC-6 conveyor systems with H-shaped bulbs, each of which is available from Fusion UV Systems, Inc., Gaithersburg, Maryland, USA. Exposure to radiation. The mold was then passed through the system five times at a speed of 10.2 cm / s (4 ″ / sec). The mold was then inverted and five more passes through the optical system at a speed of 10.2 cm / s (4 ″ / sec). And partially cured loca through the glass plate to ensure complete curing of the loca. The total UVA energy received by each cotton was about 2,500 mJ / cm 2 as measured by UV Power Puck II available from EIT, Inc., Sterling, Virginia, USA.

The Rex Gauge Company, Rex Gauge Company, Buffalo Grove, Illinois, USA, immediately after cooling the puck to room temperature for all examples except Examples 4 and 7 that were allowed to cure at room temperature for at least 16 hours. The hardness was measured with a Shore A durometer from Inc., Inc.

Viscosity measurement

Viscosity measurements were made by using an AR2000 flowmeter with a 40 mm, 1 ° stainless steel cone and plate from TA Instruments, New Castle, Delaware, USA. Viscosity was measured using a steady state flow procedure at a frequency of 0.01-25 sec ^{−1 with} a gap of 28 μm between the cone and the plate at 25 ° C. The viscosity at 25 ° C. and shear rate 1 sec ⁻¹ was recorded for the composition.

Cleavage strength and total energy

Cleavage strength measurements were made using a modified ASTM D 1062-02 cleavage strength test method. The loca was placed between standard 2.54 cm x 7.62 cm (1 "x 3") microscope slides with an overlap area of 6.45 cm 2 (1 in ² ) and a thickness of 0.13 mm (5 mil), which was two 0.13 mm (5 mil) ceramic spacer beads placed on the adhesive were used before laminating the glass slides together. Lamination consisted of placing the second slide by hand on top of the first slide with loca and beads, and manually applying pressure. Loca between these slides was cured for 10 seconds using an Omnicure 2000 high pressure Hg spot curing source (UVA energy of about 2500 mJ / cm 2), Mississauga, Ontario, Canada. The bonded glass slides were then bonded using 3M ™ Scotch-Weld ™ epoxy adhesive DP100, available from 3M Company, St. Paul, Minn., To offset the aluminum blocks specified in ASTM D 1062-02 and Allow to cure overnight before testing. This also allowed the one-part silicone to cure (Ex 4 and Ex 7). The cleavage force was measured using an MTS Insight 30 EL electromechanical test system from Prairie, Minnesota, USA. The crosshead speed at 22 ° C. (72 ° F.) was 5.08 cm / min (2 inches / min). The results are reported as maximum tear strength, namely cleavage strength (N / mm) and total energy (kg * mm). The failure mode is recorded as adhesive or cohesive.

Shrinkage measurement

Percent volume shrinkage was measured using an Accupyc II 1340 Pycnometer from Micromeritics Instrument Corporation, Norcross, GA. An uncured Loca sample of known mass was placed in a silver vial of pycnometer. The vial was placed in a pycnometer to measure the volume of the sample and the density of the loca based on the volume and mass of the sample. Sample mass was about 3.5 grams. Following the same procedure as the density measurement of the uncured loca sample, the density of the cured loca sample was measured. Molds were made of Teflon plates and cured Loca samples were prepared according to a procedure similar to that described for hardness measurements, except that the cavity size was 3.27 mm thick and 13.07 mm diameter. The volumetric shrinkage was then calculated from the following equation:

{[(1 / average liquid density)-(1 / average cured density)] / (1 / average liquid density)} × 100%

Reworkability Measurement

The ability to dissociate the loca from the glass slides, ie qualitative measurement of reworkability, was made by the following procedure: Loca was placed on a 2 mm by 3 mm glass slide of 5.08 cm by 7.62 cm (1 mm thick). Let go. The loca thickness was maintained at 0.13 mm (5 mils) by using 0.13 mm (5 mils) ceramic spacer beads placed on the adhesive prior to laminating the two glass slides together. Lamination consisted of placing the second slide by hand on top of the first slide with loca and beads, and manually applying pressure. Curing of the loca was done following the procedure described above for hardness measurement. After curing, the sample was left overnight at ambient conditions. Reworkability is measured by sliding a blade between two glass slides on a 5.08 cm (2 ") side of the glass slide to take a blade edge of about 3.81 cm (1.5") in length and initiate cleavage of the cured loca. It was. The glass slide was unruly opened by manual force on the razor blade. The time until the two glass slides were completely separated while applying force was recorded. In addition, it was also recorded whether the glass slide was broken under the applied force. The lower time until dissociation of the two glass plates was generally believed to correlate with improved reworkability. If one glass slide was broken during this process, the remaining glass attached to the other slide was removed by a similar procedure. The total time until all glasses were separated was recorded. The lower time until the two glass plates are completely unbonded was generally considered to be correlated with improved reworkability. In addition, the dissociation mode was also monitored and recorded whether the glass was broken or not and to what extent.

[Table 3]

[Table 4]

Rework of assembly

In order to facilitate cleaning of partially cured and uncured loca remaining on the surface of the cover sheet and / or LCD panel, the separate components were fully cured using appropriate curing conditions. The cured loca can be removed by stretching release due to its elastic properties. The remaining cured loca can be removed by applying a pressure sensitive adhesive tape over the cover sheet and the LCD panel. Residual cured loca can also be removed by placing a cylindrical rod over the cured loca remaining on the cover sheet and LCD panel.

The fully cured assembly of the cover sheet and the LCD panel can be separated by inserting a tote wire of, for example, stainless steel, fiberglass or nylon, which is slightly smaller in diameter than the gap size between the two components. have. The tote wire can then be passed through the two components by pulling the tote wire taut up and to the side against one of the two components. This forcibly facilitates dissociation of the two components by forcing the wires to match and applying pressure on the surface of the cover sheet. After pulling the wire through, the two components can be manually twisted to separate.

Thixotropy Loca

Viscosity measurement of thixotropic liquid optically clear adhesive compositions.

Viscosity measurements were performed by using an AR2000 flow meter with a 40 mm, 1 ° stainless steel cone and plate from TA Instruments, New Castle, Delaware, USA. Viscosity was measured using a steady state flow procedure at a frequency of 0.001 to 100 sec ^{−1 with} a gap of 28 μm at 25 ° C. between the cone and the plate.

Rotational creep measurement of thixotropic liquid optically clear adhesive compositions.

Rotational creep measurements were performed using an AR2000 flowmeter with a 40 mm diameter, 1 ° cone at 25 ° C. and recorded as the angle of rotation of the cone in radians when a stress of 10 Pa was applied to the adhesive composition for 2 minutes.

Delta measurement of thixotropic liquid optically clear adhesive composition.

Delta measurements were made using an AR2000 flowmeter with a 40 mm diameter, 1 ° cone at 25 ° C. and recorded as degrees when torque of 80 microN · m was applied for 60 seconds at a frequency of 1 Hz.

Measurement of recovery time of thixotropic liquid optically clear adhesive composition.

Recovery time measurements were made using an oscillating procedure on an AR2000 flowmeter with a 40 mm diameter, 1 ° cone at 25 ° C., and a liquid optically clear adhesive with a torque of 1000 microN · m for approximately 60 seconds at a frequency of 1 kHz. After a torque of 80 microN · m was applied immediately after the addition, the time until the decrease from its maximum value to 35 degrees with respect to the delta was recorded as the time in seconds.

Compositions for Comparative Example 3 (C3) and Example 10 were prepared according to Table 5. Add ingredients to Max 300 (approximately 500 cm 3), a white mixing vessel from Flagtech Inc., Landrum, South Carolina, USA, and use the Hauschel Speed Mixer DAC 600 FV from Flagtech Inc. Mix by running at 2200 rpm for min. In the case of Example 10, the sides of the vessel were scraped to ensure that all dry silica was incorporated, and the vessel was then mixed for an additional 4 minutes.

[Table 5]

The mixture for Example 10 was sandwiched between 2 "x 3" microscope slides at a thickness of about 200 micrometers. % T and turbidity were measured using HazeGard Plus (BWK-Gardner USA, Columbia, MD). The new coating had a% T of 92.9 (not corrected for glass) and a turbidity of 1.49%. After 72 hours at 60 ° C./85% RH, the coating had 93.0% T (not corrected for glass) and a turbidity of 0.91%.

Comparative Example 3 and Example 10 on an AR2000 flowmeter (TA Instruments, New Castle, Delaware) with a 40 mm, 1 ° stainless steel cone and plate from TA Instruments, New Castle, Delaware, at 25 ° C. The viscosity for was measured. Shear rate was increased from 0.001 sec ⁻¹ to 100 sec ⁻¹ . The viscosities at various shear rates are shown in Table 6. When the beads of Example 10 were deposited on a glass slide from the syringe / needle assembly, it did not show visually recognizable sag after 1 minute (non-sag). Example 10 meets the criteria specified herein with a viscosity at a shear rate of 1 sec ⁻¹ of 18,000 cp to 140,000 cp and a viscosity at 0.01 sec ⁻¹ of 700,000 cp to 4,200,000 cp. However, the beads of C3 had a significant deflection for the naked eye after 1 minute, although the viscosity at 1 sec ⁻¹ was 19,000 cp. C3 satisfies the criteria herein for a viscosity at a shear rate of 1 sec ⁻¹ of 18,000 cp to 140,000 cp. However, C3 has only a viscosity of 20,400 cp at a shear rate of 0.01 sec ⁻¹ and does not meet the criteria specified herein for a viscosity at 0.01 sec ⁻¹ to 700,000 cp to 4,200,000 cp.

TABLE 6

Displacement creep values were measured for Comparative Example 3 and Example 10 using an AR2000 flowmeter and a 40 mm diameter, 1 ° cone at 25 ° C., the displacement creep values of the cone being measured when the stress of 10 Pa was applied to the adhesive for 2 minutes. It is defined as the rotation angle. Example 10 meets the criteria specified herein that the displacement creep after 2 minutes is 0.021 radians and is less than 0.1 radians. However, C3 does not meet this criterion with a displacement creep of 1.08 radians after 2 minutes.

A thixotropic liquid optically clear adhesive was prepared by adding the ingredients of Table 7 to Max 300 (about 500 cm 3), a white mixing vessel from Fleck Inc., Landrum, SC, USA. It was run and mixed at 2200 rpm using a Hauschel Speedmix ™ DAC 600 FV from. After 4 minutes of mixing, the sides of the container were scraped off to ensure that all dry silica was incorporated, and then the container was mixed for an additional 4 minutes.

[Table 7]

The viscosity of Comparative Example 4 and Example 11 and Example 12 was measured as described above for Comparative Example 3 and Example 10; The results are shown in Table 8. Thixotropy was considered to be excellent if the viscosity at the shear rate of 1 sec ^-1 was 18 Pa.s to 140 Pa.s and the viscosity at 0.01 sec ^-1 was 700 Pa.s to 4200 Pa.s.

Comparative Examples 4 and 11 and 12 were sandwiched between 5.0 "cm by 7.62 cm (2" by 3 ") microscope slides at a thickness of about 200 micrometers, respectively, and 118.1 W / cm (300 W / inch). Cured using UVA energy of 3000 mJ / cm 2 as measured by a Fusion H bulb and UV power puck (IIT, Inc., Sterling, VA). Hazeguard Plus (BWK-Gardner USA, Columbia, Md.) Was used to measure turbidity. The values for turbidity are reported in Table 8. If the turbidity was less than 1%, the cured adhesive was considered excellent.

Approximately 15 g of the thixotropic agent was placed in Max 300 (approximately 500 cm 3), a container from Flandtech Inc., Landrum, South Carolina, USA, and the vessel containing the thixotropic agent was vacuum at 2000 Pa for 2 minutes at 25 ° C. The weight loss was measured by keeping at. The% weight loss was calculated using the weight of the thixotropic agent before and after the vacuum treatment, which is reported in Table 8. Example 11 with a weight loss of 0.033% showed no foaming during vacuum lamination at a pressure of 2000 Pa, while C4 with a weight loss of 0.177% showed significant foaming during vacuum lamination at a pressure of 2000 Pa.

[Table 8]

Compositions for thixotropic loca were prepared according to Table 9. Unless otherwise noted below, the ingredients are added to a white mixing vessel (Max 100 cups from Flacktec Inc., Landrum, South Carolina, USA) and the Hauschel Speedmix ™ DAC 600 FV from Flacktec Inc. The mixture was operated at 4,200 rpm for 4 minutes.

For Comparative Examples C6 to C13, BYK additive was added to the loca in a white mixing vessel (100 cups of Max from Fractech Inc., Landrum, SC, USA) and Hauschelt from Fractech Inc. The mixer was operated by running at 2200 rpm for 4 minutes using a Speedmix ™ DAC 600 FV. A200 was added to the contents of the mixing cup and then mixed by running at 2200 rpm for 4 minutes using the Hauschel SpeedMix ™ DAC 600 FV from FLEXTECH INC.

For Comparative Examples C19-C21, the mixed contents were heated to 100 ° C. for 30 minutes to incorporate the thixotropic additive. After heating, the mixed contents were allowed to cool to room temperature and then mixed by running at 2200 rpm for 4 minutes using the Hauschel SpeedMix ™ DAC 600 FV from Fractech Inc.

Comparative Example C30 is unmodified Loca 2312.

TABLE 9

For Example 15, 0.26 g of A100 was added to 5 g of DBA1000 in a white mixing vessel (60 cups of Max from Fractech Inc., Landrum, South Carolina, USA) and from Howe from Fractech Inc. The mixture was operated by running at 2200 rpm for 4 minutes using Schilt SpeedMix ™ DAC 600 FV. Comparative Example C30 is an unmodified DBA1000.

Compositions for the comparative examples of thixotropic loca based on SVR1300 were prepared according to Table 10. Unless otherwise noted below, the ingredients are added to a white mixing vessel (Max 100 cups from Flacktec Inc., Landrum, South Carolina, USA) and the Hauschel Speedmix ™ DAC 600 FV from Flacktec Inc. The mixture was operated at 4,200 rpm for 4 minutes. Comparative Example C32 is an unmodified SVR1300.

[Table 10]

Rheological Measurement

Viscosity, displacement creep and delta measurements can be found in Table 11.

TABLE 11

Optical properties of thixotropic loca

Permeability,% T, and turbidity were measured using Haysguard Plus (BW-Gardner USA, Columbia, Md.). The results are compiled in Table 12 and had at least three measurements for each property.

[Table 12]

Stock solution 1 by mixing 85.45 parts of Yu-Pica 8967A, 30.86 parts of CD611, 42.73 parts of SR506A, 28.48 parts of KE311, 213.74 parts of bisomer PPA6, 23.74 parts of soybean oil and 2.50 parts of TPO-L, where parts are parts by weight. 1, SS1) was prepared.

Stock solution 2 (SS2) was prepared by mixing 93.2 parts CN9018, 80.4 parts CD611, 64.3 parts SRS506A, 48.2 parts bisomer PPA6, 32.2 parts soybean oil and 3.22 parts TPO-L.

Stock solution 3 (SS3) by mixing 185.3 parts of Yu-Pica 8967A, 73.4 parts of Yu-Pica 8967AX, 40.6 parts of CD611, 56.2 parts of SR506A, 67.8 parts of KE311, 31.2 parts of bisomer PPA6, 38 parts of soybean oil, and 7.5 parts of TPO-L. ) Was prepared.

The following comparative examples and examples were prepared according to Table 13.

[Table 13]

The viscosity, delta, rotary creep, and turbidity of C31 to C37 and E16 to E18 are shown in Table 14.

[Table 14]

The recovery times from delta reduction to 35 degrees from the delta maximum are listed in Table 15.

[Table 15]

Comparative Example C38 and Comparative Example C39 were prepared according to Table 16.

[Table 16]

Comparative Example C38 and Comparative Example C39 on an AR2000 flowmeter (Tay Instruments, New Castle, Delaware) with a 40 mm, 1 ° stainless steel cone and plate from TA Instruments, New Castle, Delaware, at 25 ° C. The viscosity for was measured. Shear rate was increased from 0.001 sec ⁻¹ to 100 sec ⁻¹ . The viscosities at various shear rates are shown in Table 17.

TABLE 17

The 150 micron thick coating of Example 19 was prepared between 1 mm thick microscopic glass slides and exposed to UVA energy of 3000 mJ / cm 2 as measured using an Eiti Power Puck II radiometer. Turbidity and% T measured using BWK Gardner HazeGuard Plus were 91.6% and 3.1%, respectively.

A number of embodiments of the invention have been described. It is understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (77)

Display panel;
A substantially transparent substrate; And
An adhesive layer disposed between the display panel and the substantially transparent substrate,
The adhesive layer is
Reaction products of a multifunctional (meth) acrylate oligomer and a reactive diluent comprising a monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. of about 4 to about 20 cp; And
An optical assembly comprising a plasticizer. The method of claim 1, wherein the multifunctional (meth) acrylate oligomer
Multifunctional urethane (meth) acrylate oligomers,
Multifunctional polyester (meth) acrylate oligomers, and
An optical assembly comprising any one or more of a multifunctional polyether (meth) acrylate oligomer. The optical assembly of claim 1, wherein the multifunctional (meth) acrylate oligomer comprises a multifunctional urethane (meth) acrylate oligomer. The monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. of about 4 to about 20 cps according to claim 1, wherein the monofunctional (meth) acrylate monomer comprises tetrahydrofurfuryl (meth) acrylate and isobornyl (meth) acrylate. Assembly. The optical assembly of claim 4 wherein the tetrahydrofurfuryl (meth) acrylate comprises alkoxylated tetrahydrofurfuryl acrylate. The optical assembly of claim 1 or 3, wherein the plasticizer comprises an oil. The optical assembly of claim 1 or 4, wherein the reaction product further comprises a monofunctional (meth) acrylate monomer having an alkylene oxide functional group. The method of claim 1 wherein the adhesive layer is
Reaction product of about 20 to about 60 weight percent multifunctional (meth) acrylate oligomer with about 30 to about 60 weight percent reactive diluent; And
Greater than 5 wt% to about 25 wt% plasticizer. Display panel;
A substantially transparent substrate; And
An adhesive layer disposed between the display panel and the substantially transparent substrate,
The adhesive layer is
Reactivity comprising a polyfunctional (meth) acrylate oligomer and a monofunctional (meth) acrylate monomer having an alkylene oxide functional group and a monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. of about 4 to about 20 cp. An optical assembly comprising the reaction product of a diluent. The method of claim 9, wherein the multifunctional (meth) acrylate oligomer is
Multifunctional urethane (meth) acrylate oligomers,
Multifunctional polyester (meth) acrylate oligomers, and
An optical assembly comprising any one or more of a multifunctional polyether (meth) acrylate oligomer. The monofunctional (meth) acrylate monomer of claim 9, wherein the monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. is from about 4 to about 20 cp, comprises tetrahydrofurfuryl (meth) acrylate and isobornyl (meth) acrylate, The monofunctional (meth) acrylate monomer having alkylene oxide functional groups has 1 to 10 alkylene oxide units. The optical assembly of claim 11, wherein the tetrahydrofurfuryl (meth) acrylate comprises alkoxylated tetrahydrofurfuryl acrylate. The optical assembly of claim 11, wherein the multifunctional (meth) acrylate oligomer comprises a multifunctional urethane (meth) acrylate oligomer. 10. The optical assembly of claim 9, wherein the adhesive layer comprises a reaction product of about 20 to about 60 weight percent multifunctional (meth) acrylate oligomer with about 40 to about 80 weight percent reactive diluent. Display panel;
A substantially transparent substrate; And
An adhesive layer disposed between the display panel and the substantially transparent substrate,
The adhesive layer is
Reaction products of multifunctional rubber-based (meth) acrylate oligomers with monofunctional (meth) acrylate monomers having pendant alkyl groups of 4 to 20 carbon atoms; And
An optical assembly comprising liquid rubber. The method of claim 15, wherein the multifunctional rubber-based (meth) acrylate oligomer is
Multifunctional polybutadiene (meth) acrylate oligomers,
Multifunctional isoprene (meth) acrylate oligomers, and
An optical assembly comprising any one or more of a multifunctional (meth) acrylate oligomer comprising a copolymer of butadiene and isoprene. The optical assembly of claim 15, wherein the multifunctional rubber-based (meth) acrylate oligomer comprises a multifunctional polybutadiene (meth) acrylate oligomer. The optical assembly of claim 15, wherein the pendant alkyl group comprises 8 to 20 carbon atoms. 19. The optical assembly of claim 15 or 18, wherein the liquid rubber comprises liquid isoprene. 19. The optical assembly of claim 15 or 18, further comprising a plasticizer. The optical assembly of claim 20, wherein the plasticizer comprises an oil. The method of claim 15, wherein the adhesive layer is
Reaction of about 20 to about 60 weight percent multifunctional rubber-based (meth) acrylate oligomer with monofunctional (meth) acrylate monomer having from about 20 to about 60 weight percent pendant alkyl groups of 4 to 20 carbon atoms product; And
An optical assembly comprising more than 5 wt% to about 25 wt% liquid rubber. The optical assembly of claim 1, 9, or 15, wherein the adhesive layer is substantially free of tackifiers. The optical assembly of claim 1, 9, or 15, wherein the adhesive layer further comprises silica. The optical assembly of claim 1, 9, or 15, wherein the adhesive layer has a cleavage strength between glass substrates of about 15 N / mm or less. The optical assembly of claim 1, 9, or 15, wherein the adhesive layer has a thickness of about 1 um to about 5 mm. The optical assembly of claim 1, 9, or 15, wherein the display panel comprises a liquid crystal display panel. The optical assembly of claim 1, 9, or 15, wherein the substantially transparent substrate comprises a touch screen. The optical assembly of claim 1, 9, or 15, wherein the area is from about 15 cm 2 to about 5 m 2. Display panel;
A substantially transparent substrate; And
A liquid composition disposed between the display panel and the substantially transparent substrate, the liquid composition having a viscosity at 25 ° C. and 1 sec ⁻¹ of about 100 to about 140,000 cp,
Multifunctional (meth) acrylate oligomers,
Monofunctional (meth) acrylate monomers having a viscosity at about 25 ° C. of from about 4 to about 20 cp,
An optical assembly comprising a plasticizer. The optical assembly of claim 30, wherein the viscosity of the liquid composition at 25 ° C. and 1 sec ⁻¹ is about 100 to 10,000 cp. The method of claim 30, wherein the multifunctional (meth) acrylate oligomer
Multifunctional urethane (meth) acrylate oligomers,
Multifunctional polyester (meth) acrylate oligomers, and
An optical assembly comprising any one or more of a multifunctional polyether (meth) acrylate oligomer. 31. The optical assembly of claim 30, wherein the multifunctional (meth) acrylate oligomer comprises a multifunctional urethane (meth) acrylate oligomer. 31. The monofunctional (meth) acrylate monomer having a viscosity at about 25 [deg.] C. of about 4 to about 20 cps according to claim 30, wherein the monofunctional (meth) acrylate monomer comprises tetrahydrofurfuryl (meth) acrylate and isobornyl (meth) acrylate. Assembly. 35. The optical assembly of claim 34, wherein the tetrahydrofurfuryl (meth) acrylate comprises alkoxylated tetrahydrofurfuryl acrylate. 35. The optical assembly of claim 30 or 34, wherein the plasticizer comprises an oil. 36. The optical assembly of claim 30 or 35, wherein the liquid composition further comprises a monofunctional (meth) acrylate monomer having an alkylene oxide functional group. 33. The liquid composition of claim 30, wherein the liquid composition is
About 20 to about 60 weight percent of a multifunctional (meth) acrylate oligomer,
About 30 to about 60 weight percent monofunctional (meth) acrylate monomer, and
Greater than 5 wt% to about 25 wt% plasticizer. Display panel;
A substantially transparent substrate; And
A liquid composition disposed between the display panel and the substantially transparent substrate, the liquid composition having a viscosity at 25 ° C. and 1 sec ⁻¹ of about 100 to about 140,000 cp,
Multifunctional (meth) acrylate oligomers,
Monofunctional (meth) acrylate monomers having a viscosity at about 25 ° C. of from about 4 to about 20 cp,
An optical assembly comprising a monofunctional (meth) acrylate monomer having an alkylene oxide functional group. The optical assembly of claim 39, wherein the viscosity of the liquid composition at 25 ° C. and 1 sec ⁻¹ is about 100 to 10,000 cp. 40. The method of claim 39, wherein the multifunctional (meth) acrylate oligomer is
Multifunctional urethane (meth) acrylate oligomers,
Multifunctional polyester (meth) acrylate oligomers, and
An optical assembly comprising any one or more of a multifunctional polyether (meth) acrylate oligomer. 41. The monofunctional (meth) acrylate monomer of claim 40, wherein the monofunctional (meth) acrylate monomer having a viscosity at about 25 [deg.] C. is from about 4 to about 20 cps, comprises tetrahydrofurfuryl (meth) acrylate and isobornyl (meth) acrylate, The monofunctional (meth) acrylate monomer having alkylene oxide functional groups has 1 to 10 alkylene oxide units. 43. The optical assembly of claim 42, wherein the tetrahydrofurfuryl (meth) acrylate comprises alkoxylated tetrahydrofurfuryl acrylate. The optical assembly of claim 43, wherein the multifunctional (meth) acrylate oligomer comprises a multifunctional urethane (meth) acrylate oligomer. 41. The liquid composition of claim 40, wherein the liquid composition is
About 20 to about 60 weight percent of a multifunctional (meth) acrylate oligomer,
About 40 to about 80 weight percent of a reactive diluent. Display panel;
A substantially transparent substrate; And
A liquid composition disposed between the display panel and the substantially transparent substrate,
The liquid composition has a viscosity at 25 ° C. and 1 sec ⁻¹ of about 100 to about 140,000 cp,
Multifunctional rubber-based (meth) acrylate oligomers,
Monofunctional (meth) acrylate monomers having pendant alkyl groups of 4 to 20 carbon atoms,
An optical assembly comprising liquid rubber. The optical assembly of claim 46, wherein the viscosity of the liquid composition at 25 ° C. and 1 sec ⁻¹ is about 100 to 10,000 cp. The method of claim 46, wherein the multifunctional rubber-based (meth) acrylate oligomer is
Multifunctional polybutadiene (meth) acrylate oligomers,
Multifunctional isoprene (meth) acrylate oligomers, and
An optical assembly comprising any one or more of a multifunctional (meth) acrylate oligomer comprising a copolymer of butadiene and isoprene. 47. The optical assembly of claim 46, wherein the multifunctional rubber-based (meth) acrylate oligomer comprises a multifunctional polybutadiene (meth) acrylate oligomer. The optical assembly of claim 46, wherein the pendant alkyl group comprises 8 to 20 carbon atoms. 51. The optical assembly of claim 46 or 50, wherein the liquid rubber comprises liquid isoprene. 51. The optical assembly of claim 46 or 50, further comprising a plasticizer. The optical assembly of claim 52, wherein the plasticizer comprises an oil. 47. The liquid composition of claim 46, wherein the liquid composition is
About 20 to about 60 weight percent of the multifunctional rubber-based (meth) acrylate oligomer,
Monofunctional (meth) acrylate monomer having from about 20 to about 60 weight percent of a pendant alkyl group of 4 to 20 carbon atoms, and
An optical assembly comprising more than 5 wt% to about 25 wt% liquid rubber. 47. The optical assembly of any one of claims 30, 39, and 46, wherein the liquid composition is substantially free of tackifiers. 47. The optical assembly of any of claims 30, 39 and 46, wherein the liquid composition has a thickness of about 1 um to about 5 mm. 47. The optical assembly of any of claims 30, 39 and 46, wherein the display panel comprises a liquid crystal display panel. 47. The optical assembly of any of claims 30, 39 and 46, wherein the substantially transparent substrate comprises a touch screen. 47. The optical assembly of any of claims 30, 39 and 46, wherein the area is from about 15 cm 2 to about 5 m 2. Providing a display panel;
Providing a substantially transparent substrate;
A liquid composition comprising a polyfunctional (meth) acrylate oligomer, a monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. of about 4 to about 20 cps, and a plasticizer, is prepared in a display panel and a substrate. Placing on one;
Disposing one of the display panel and the substrate on the liquid composition;
Curing the liquid composition by applying actinic radiation. Providing a display panel;
Providing a substantially transparent substrate;
Reactivity comprising a polyfunctional (meth) acrylate oligomer and a monofunctional (meth) acrylate monomer having an alkylene oxide functional group and a monofunctional (meth) acrylate monomer having a viscosity at about 25 ° C. of about 4 to about 20 cp. Disposing a liquid composition comprising a diluent on one of the display panel and the substrate;
Disposing one of the display panel and the substrate on the liquid composition;
Curing the liquid composition by applying actinic radiation. Providing a display panel;
Providing a substantially transparent substrate;
A liquid composition comprising a multifunctional rubber-based (meth) acrylate oligomer, a monofunctional (meth) acrylate monomer having pendant alkyl groups of 4 to 20 carbon atoms, and a liquid rubber is placed on one of the display panel and the substrate. And disposing the optical assembly. Providing a display panel;
Providing a substantially transparent substrate;
Disposing a polymerizable liquid composition having a viscosity of about 100 to about 10,000 cp on one of the display panel and the substrate;
Disposing one of the display panel and the substrate on the polymerizable liquid composition;
Polymerizing the polymerizable liquid composition by applying actinic radiation. 64. The method of any one of claims 60, 61, 62, and 63, wherein the optical assembly has an area of about 15 cm 2 to about 5 m 2. Providing an optical assembly comprising a display panel, a substantially transparent substrate, and an adhesive layer disposed between the display panel and the substrate and having a cleavage strength between the glass substrates of about 15 N / mm or less;
Separating the display panel and the substrate from each other. 66. The method of claim 65, wherein the optical assembly has an area of about 15 cm 2 to about 5 m 2. 47. The method of any of claims 1, 9, 15, 30, 39 and 46, including a handheld device, television, computer monitor, laptop display, or digital sign. An optical device comprising an optical assembly. 47. The optical assembly of any of claims 30, 39, and 46, wherein the liquid composition further comprises silica. Liquid optically clear adhesive having a viscosity at a shear rate of 1 sec ⁻¹ of less than about 20 Pa · s; And
Thixotropic agents;
Haze is about 2% or less;
The viscosity at a shear rate of 10 sec ⁻¹ is about 2 to about 30 Pa · s, and the viscosity at a shear rate of 0.01 sec ⁻¹ is about 700 to about 10,000 Pa · s;
The displacement creep is about 0.2 radians or less when a stress of 10 Pa is applied for about 2 minutes;
The recovery time is less than about 60 seconds after reaching approximately 1000 microNm for about 60 seconds at a frequency of 1 Hz and reaching a delta of 35 degrees after applying 80 microNm of torque at a frequency of 1 Hz. Optically transparent adhesive layer. The optically clear adhesive layer of claim 69, wherein the delta is less than or equal to about 42 degrees when a torque of 80 microN · m is applied at a frequency of 1 Hz. The optically clear of claim 69, wherein the viscosity at a shear rate of 10 sec ⁻¹ is about 5 to about 20 Pa · s and the viscosity at a shear rate of 0.01 sec ⁻¹⁰ is about 1,000 to about 8,000 Pa · s. Adhesive layer. The optically clear adhesive layer of claim 69, wherein the viscosity at a shear rate of 1 sec ⁻¹ is about 17 to about 140 Pa · s. 70. The optically clear adhesive layer of claim 69, wherein when the stress of 10 Pa is applied for about 2 minutes, the displacement creep is about 0.1 radians or less. The optically clear adhesive layer of claim 69, wherein the liquid optically clear adhesive has a viscosity at a shear rate of 1 sec ⁻¹ of less than about 10 Pa · s. 70. The method of claim 69, wherein the recovery to a delta of 35 degrees is achieved after 80 microN · m of torque is applied at a frequency of 1 Hz immediately after a torque of about 1000 microN · m is applied for about 60 seconds at a frequency of 1 Hz. An optically clear adhesive layer having a time of about 30 seconds or less. 70. The method of claim 69, wherein the recovery to a delta of 35 degrees is achieved after 80 microN · m of torque is applied at a frequency of 1 Hz immediately after a torque of about 1000 microN · m is applied for about 60 seconds at a frequency of 1 Hz. An optically clear adhesive layer having a time of about 10 seconds or less. 70. The thixotropic agent of claim 69 wherein the thixotropic agent is dry silica, dry aluminum oxide, polyhydroxycarboxylic acid amide, polyhydroxycarboxylic acid ester, modified urea, metal sulfonate, acrylated oligoamine, polyacrylic acid, and An optically clear adhesive layer selected from the group consisting of modified urethanes.