Siloxane-based optically clear adhesive with corrosion resistant properties

Abstract

The siloxane-based corrosion resistant adhesive is prepared from a reaction mixture such that after curing in the form of a layer, the formed siloxane-based adhesive has a stable modulus and a shear storage modulus at a frequency of 1 Hz of no more than 0.2 MPa as measured by DMA (Dynamic Mechanical Analysis). In addition, the cured siloxane-based adhesive layer is optically transparent, and after lamination to a silver nanowire film, the silver nanowire film has a change in resistance of less than 10% after aging for 500 hours at a relative humidity of 65 DEG C / 90%. The reaction mixture forming the siloxane-based adhesive includes at least one vinyl-functionalized siloxane, at least one hydrogen-functionalized siloxane, at least one hydrosilylation catalyst, at least one siloxane tackifying resin, and at least one anticorrosive agent.

Description

Summary of the Invention

[0001] This article discloses corrosion-resistant adhesive compositions, laminated articles prepared using these corrosion-resistant adhesive compositions, and methods for preparing these laminated articles.

[0002] In some embodiments, the corrosion-resistant adhesive composition comprises a siloxane adhesive prepared from the reaction mixture, such that, after curing in layer form, the siloxane adhesive exhibits a stable modulus over a temperature range between approximately -30°C and 70°C, as measured by DMA (Dynamic Mechanical Analysis), and the cured adhesive layer has a shear storage modulus of no more than 0.2 MPa at a frequency of 1 Hz. Furthermore, the cured siloxane adhesive layer is optically transparent, and after laminating the cured siloxane adhesive layer onto a silver nanowire film, the change in resistivity of the silver nanowire film after aging at 65°C / 90% relative humidity for 500 hours is less than 10%. The reaction mixture forming the siloxane adhesive comprises at least one vinyl-functionalized siloxane, at least one hydrogen-functionalized siloxane, at least one hydrogenated silanization catalyst, at least one siloxane tackifying resin, and at least one corrosion inhibitor.

[0003] This document also discloses laminated articles. In some embodiments, the laminated article includes a first substrate having a first main surface and a second main surface, an adhesive layer disposed on at least a portion of the second main surface of the first substrate, and a second substrate having a first main surface and a second main surface, wherein the first main surface of the second substrate is disposed on the adhesive layer. The adhesive layer comprises a layer of cured silicone-based adhesive as described above.

[0004] A method for preparing a laminated article is also disclosed. In some embodiments, the method for preparing a laminated article includes providing a first substrate having a first main surface and a second main surface; providing a reaction mixture for preparing a siloxane adhesive or providing a siloxane adhesive layer; disposing the reaction mixture or the siloxane adhesive layer on at least a portion of the second main surface of the first substrate; if a reaction mixture is used, curing the reaction mixture to form the siloxane adhesive layer; providing a second substrate having a first main surface and a second main surface; and disposing the first main surface of the second substrate on the siloxane adhesive layer. If a reaction mixture is used, the reaction comprises at least one vinyl-functionalized siloxane, at least one hydrogen-functionalized siloxane, at least one hydrogenation silanization catalyst, at least one siloxane tackifying resin, and at least one corrosion inhibitor. If a siloxane adhesive layer is used, the siloxane adhesive layer is a cured layer of the reaction mixture. Attached Figure Description

[0005] This application can be more fully understood by referring to the following detailed description of various embodiments of this disclosure in conjunction with the accompanying drawings.

[0006] Figure 1 This is a cross-sectional view of the article disclosed herein. Detailed Implementation

[0007] Many optical products have multiple layers. These layers are typically bonded together with adhesive layers. These adhesive layers have a variety of desired or required properties. Achieving some of these properties is a very complex process. Adhesive layers are designed to bond two films or substrates together, but additional properties are often required for the adhesive layers. Many of these properties are difficult to achieve because imparting new properties to the adhesive layers must be done without sacrificing the adhesive properties.

[0008] A range of optically transparent adhesives have been developed for use in optical articles. These adhesives possess both adhesive properties and optical transparency. This combination of properties makes them well-suited for a variety of applications. In some applications, additional properties are desired in optically transparent adhesives. However, these new properties cannot be achieved by sacrificing either adhesive or optical properties.

[0009] Foldable articles require optically transparent adhesives. Examples include flexible OLED displays in foldable phones, tablets, and laptops. Furthermore, the trend in such devices is towards reduced thickness and smaller folding radii. This imposes numerous design constraints on the display materials. For instance, a thin adhesive layer is expected to reduce stress generated during folding while still providing high adhesion to a variety of substrates. Additionally, OLED displays need to operate over a wide temperature range without cracking or temporary deformation due to material creep when the device is folded, rolled up, bent, or flexed. However, peel adhesion is often observed to be reduced by materials with these properties. Weaker peel adhesion can further increase the risk of delamination during dynamic folding. Therefore, an adhesive film that provides adequate adhesion to the mechanical deformation associated with folding and to suitable device substrates is crucial for overall device performance.

[0010] Among the pressure-sensitive adhesives developed for optical applications are siloxane-based pressure-sensitive adhesives, commonly referred to as "organosilicone PSAs." However, these siloxane-based PSAs often present problems when laminated onto nanowire layers. Typically, siloxane-based PSAs are incompatible with nanowire layers and cause an increase in the resistance of the nanowire layers after aging. The nanowire layers are usually metal nanowire films.

[0011] Metal nanowire films are films on which metal nanowires are deposited. As the name suggests, nanowires are lines with diameters in the nanometer range (typically 10 to 200 nanometers). These films are typically less than 100 micrometers thick and are frequently used in flexible electronics due to their combination of high conductivity, the ability to bend to narrow radii with limited variation in conductivity, and high optical transparency. Nanowire films can be used in applications such as capacitive touch sensors, chemical sensors, optical sensors, and antennas, where they can also be optically transparent. A variety of metals can be used to fabricate nanowire films. Typically, highly conductive metals, such as copper and silver, are used. Silver nanowire films are commonly used in many applications.

[0012] There is a need for adhesive films that possess a desired balance of peel adhesion, low haze, low Tg, and low modulus, and are compatible with nanowire layers. This disclosure describes corrosion-resistant adhesive films comprising a siloxane polymer matrix prepared by a catalytic reaction of vinyl-functionalized and hydroxyl-functionalized siloxanes, a siloxane tackifying resin, and a corrosion inhibitor. These adhesives exhibit this desired balance of properties.

[0013] As used herein, the term "adhesive" refers to a polymer composition that can be used to adhere two adhesives together. An example of an adhesive is a pressure-sensitive adhesive.

[0014] Those skilled in the art are well aware that pressure-sensitive adhesive compositions possess properties including (1) strong and durable adhesion, (2) adhesion with no more than finger pressure, (3) sufficient ability to hold onto the adhesive, and (4) sufficient cohesive strength to allow for clean removal from the adhesive. Materials found to be well-suited for use as pressure-sensitive adhesives are polymers designed and formulated to exhibit the desired viscoelastic properties, thereby achieving a desired balance between tack, peel adhesion, and shear retention. Achieving this proper balance of properties is not a simple process.

[0015] As used in this article, the term "OCA" refers to optically transparent adhesives.

[0016] Many widely used and popular pressure-sensitive adhesives are based on (meth)acrylates. The term "(meth)acrylate" refers to the monomeric acrylate or methacrylate of an alcohol. Acrylates and methacrylate monomers or oligomers are collectively referred to herein as "(meth)acrylates". Materials referred to as "(meth)acrylate functionalized" are materials containing one or more (meth)acrylate groups.

[0017] Although pressure-sensitive adhesives based on siloxane chemistry, especially optically transparent adhesives (organosilicon OCA or SiOCA), are not very common, siloxane OCAs do exhibit a class of materials with unique properties, such as relatively low refractive index and stability after environmental aging. As used herein, the terms "siloxane" and "siloxane-alkyl" refer to polymers or polymer units containing siloxane units. The terms organosilicon or siloxane are used interchangeably and refer to units having repeating dialkyl or diarylsiloxane (-SiR2O-) units.

[0018] The terms “room temperature” and “ambient temperature” are used interchangeably, referring to temperatures in the range of 20°C to 25°C.

[0019] The terms "Tg" and "glass transition temperature" are used interchangeably. If measured, unless otherwise specified, the Tg value is determined by differential scanning calorimetry (DSC) at a scan rate of 10 °C / min. Typically, the Tg value of the copolymer is not measured, but rather calculated using the well-known Fox formula, using the monomer Tg values ​​provided by the monomer supplier, as understood by those skilled in the art.

[0020] As used in this article, the term "adjacent" in the context of two floors means that the two floors are adjacent to each other and there is no intervening opening space between them. They may be in direct contact with each other (e.g., laminated together) or there may be an intervening floor.

[0021] As used herein, the terms “polymer” and “macromolecule” are consistent with their common usage in chemistry. Polymers and macromolecules are composed of many repeating subunits. As used herein, the term “macromolecule” is used to describe a group having multiple repeating units attached to a monomer. The term “polymer” is used to describe the material obtained by a polymerization reaction.

[0022] The term "alkyl" refers to a monovalent group that is an alkane group, where the alkane is a saturated hydrocarbon. Alkyl groups can be straight-chain, branched, cyclic, or combinations thereof, and typically have 1 to 20 carbon atoms. In some embodiments, the alkyl group contains 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, and ethylhexyl.

[0023] The term "aryl" refers to a monovalent group consisting of an aromatic ring and a carbocyclic ring. An aryl group can have one to five rings attached to or fused with an aromatic ring. Other ring structures can be aromatic, non-aromatic, or combinations thereof. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, anthryl, naphthyl, acenaphthenic, anthraquinone, phenanthryl, anthracenyl, pyrene, peryl, and fluorenyl.

[0024] Unless otherwise specified, the terms "optically transparent" and "visible light transmittance" are used interchangeably and refer to articles, films, or adhesives having high transmittance over at least a portion of the visible light spectrum (about 400 nm to about 700 nm). Typically, optically transparent articles have at least 90% visible light transmittance and less than 10% haze.

[0025] Unless otherwise specified, "optically transparent" means an adhesive or article that has high transmittance and exhibits low haze (typically less than about 5%, or even less than about 2%) over at least a portion of the visible light spectrum (about 400 nm to about 700 nm). In some embodiments, the optically transparent article exhibits haze of less than 1% or even 0.5% at a thickness of 50 micrometers. Typically, the optically transparent article has a visible light transmittance of at least 95%, typically higher, such as 97%, 98%, or even 99% or higher.

[0026] As used herein, the terms “flexible” and “rigid” are used according to their common understanding. A flexible substrate is capable of bending without breaking or fracturing, while a rigid substrate is not capable of bending without breaking or fracturing. Generally, a flexible substrate is one that can bend from an angle of 0° to at least 45° or even 90° or greater, and then bend back to an angle of 0° without being damaged by breaking or fracturing.

[0027] This document discloses siloxane-based corrosion-resistant adhesive compositions. The corrosion-resistant adhesive compositions are cured to form corrosion-resistant adhesives. Typically, the corrosion-resistant adhesives are pressure-sensitive adhesives. In some embodiments, the corrosion-resistant adhesive composition forming the corrosion-resistant adhesive after curing comprises a reaction mixture containing at least one vinyl-functionalized siloxane, at least one hydrogen-functionalized siloxane, at least one hydrogenated silanization catalyst, at least one siloxane tackifying resin, and at least one corrosion inhibitor. Each of these components is described in more detail below.

[0028] After curing in layer form, the siloxane adhesive exhibited a stable modulus over a temperature range of approximately -30°C to 70°C, as measured by DMA (Dynamic Dynamics Analysis). The cured adhesive layer also possessed a shear storage modulus not exceeding 0.2 MPa at a frequency of 1 Hz. The cured siloxane adhesive layer was optically transparent and corrosion-resistant after lamination. Corrosion resistance was defined as a change in electrical resistance of less than 10% after the silver nanowire film was aged at 65°C / 90% relative humidity for 500 hours following lamination of the cured siloxane adhesive layer.

[0029] The reaction mixture forming the corrosion-resistant adhesive comprises at least one vinyl-functionalized siloxane. A variety of vinyl-functionalized siloxanes are suitable. In some embodiments, at least one vinyl-functionalized siloxane is shown in Formula 1:

[0030] R1, R2, R3, and R4 are each independently selected from the group consisting of alkyl groups, aryl groups, and olefinic unsaturated groups; each R5 is an alkyl group; each X is an olefinic unsaturated group or an alkyl group; and n and m are integers, and at least one of m or n is not 0. If the X group is not an olefinic unsaturated group, then at least one of R1 and R3 is an olefinic unsaturated group.

[0031] Vinyl functionalized siloxanes of Formula I in which the X group is olefinically unsaturated are referred to as "terminal functionalized" siloxanes, and those vinyl functionalized siloxanes in which the X group is not olefinically unsaturated and at least one of R1 and R3 is olefinically unsaturated are referred to as "side-group functionalized" siloxanes. Alternatively, the vinyl functionalized siloxanes may be of Formula I, in which the X group is olefinically unsaturated and at least one of R1 and R3 is olefinically unsaturated.

[0032] In some embodiments, the vinyl-functionalized siloxane forming the reaction mixture of the corrosion-resistant pressure-sensitive adhesive is a side-functionalized vinyl-functionalized siloxane. It may be desirable that only one of groups R1 and R3 is olefinically unsaturated.

[0033] In some particularly suitable embodiments, at least one vinyl-functionalized siloxane is represented by formula 1A:

[0034] R1, R2, R3, and R4 are each independently selected from the group consisting of alkyl or aryl groups; each R5 is an alkyl group; each X is an olefinic unsaturated group; and n and m are integers, and at least m is not 0.

[0035] A variety of vinyl-functionalized siloxanes are commercially available. Of particular suitability is DEHESIVE 948, which is available from Wacker.

[0036] The reaction mixture forming the corrosion-resistant adhesive contains at least one hydrogen-functionalized siloxane. A variety of hydrogen-functionalized siloxanes are suitable. In some embodiments, at least one hydrogen-functionalized siloxane is shown by Formula 2:

[0037] R1, R2, R3, and R4 are independently selected from the group consisting of alkyl groups, aryl groups, and hydrogen groups; each R5 is an alkyl group; and n and m are integers, and at least one of m or n is not 0.

[0038] In some particularly suitable embodiments, at least one hydrogen-functionalized siloxane is represented by formula 2A:

[0039] Where R1 is a hydrogen group, R2, R3 and R4 are independently selected from the group consisting of alkyl groups or aryl groups; each R5 is an alkyl group; and n and m are integers, and at least m is not 0.

[0040] A variety of hydrogen-functionalized siloxanes are commercially available. HMS-151 is particularly suitable and is available from Gelest Inc., Morrisville, PA.

[0041] The reaction mixture forming the corrosion-resistant binder contains at least one hydrosilylation catalyst. The catalyst promotes the hydrosilylation reaction, i.e., the reaction between a vinyl-functionalized siloxane and a hydrogen-functionalized siloxane. Various catalysts are suitable, but platinum-based (Pt-based) catalysts are particularly suitable. Pt-based catalysts catalyze the reaction between the vinyl groups on the vinyl-functionalized siloxane and the hydride groups on the hydrogen-functionalized siloxane. Examples of commercially available platinum catalysts include, but are not limited to, SIP 6831.2 from Gelest, a platinum-divinyltetramethyldisiloxane complex in xylene. Typical platinum catalyst concentrations are between about 50 ppm and about 150 ppm platinum.

[0042] The reaction mixture forming the corrosion-resistant adhesive comprises at least one siloxane tackifying resin. The siloxane tackifying resin is added to the reaction mixture. Various tackifying resins are suitable. MQ resins are particularly suitable. Available MQ tackifying resins include, for example, MQ silicone resins, MQD silicone resins, and MQT silicone resins. These tackifying resins typically have a number average molecular weight of about 100 to about 50,000, or about 500 to about 20,000, and generally have methyl substituents. MQ silicone resins include nonfunctional resins and functional resins, the functional resins having one or more functional groups, including, for example, silicon-bonded hydrogen, silicon-bonded alkenyl groups, and silanols.

[0043] MQ silicone resin is a type of silicone resin containing R'3SiO 1 / 2 Unit (M unit) and SiO 4 / 2Copolymer silicone resins of the Q unit (Q unit). Such resins are described, for example, in the following patents and documents: Encyclopedia of Polymer Science and Engineering, vol. 15, John Wiley & Sons, New York, (1989), pp. 265 to 270, and U.S. Patent Nos. 2,676,182 (Daudt et al.), 3,627,851 (Brady), 3,772,247 (Flannigan), and 5,248,739 (Schmidt et al.). Functional MQ silicone resins are described in the following patents: U.S. Patent 4,774,310 (Butler) describing silyl hydride groups, U.S. Patent 5,262,558 (Kobayashi et al.) describing vinyl and trifluoropropyl groups, and U.S. Patent 4,707,531 (Shirahata) describing silyl hydride and vinyl groups. The resins described above are typically prepared in solvents. Descriptions of the preparation of dried or solvent-free MQ silicone resins are found in U.S. Patent Nos. 5,319,040 (Wengrovius et al.), 5,302,685 (Tsumura), and 4,935,484 (Wolfgruber).

[0044] MQD silicone resin is a type of silicone resin containing R'3SiO 1 / 2 Unit (M unit), SiO 4 / 2 Unit (Q unit) and R'2SiO 2 / 2 Terpolymers of units (D units), such as those described in U.S. Patent 5,110,890 (Butler).

[0045] MQT silicone resin is a type of silicone resin containing R3SiO 1 / 2 Unit (M unit), SiO 4 / 2 Unit (Q unit) and RSiO 3 / 2 Terpolymers of unit (T unit) (MQT resin).

[0046] MQ silicone resins are typically supplied in organic solvents. Examples of commercially available suitable MQ resins (also known as tackifiers) include 2-7066 supplied by Dow Corning in 60% toluene solution and SR545 supplied by Momentive. In one embodiment, the MQ silicone resin may also comprise a blend of two or more silicone resins.

[0047] The reaction mixture forming the corrosion-resistant adhesive contains at least one corrosion inhibitor. The corrosion inhibitor is typically added to the reaction mixture. A variety of corrosion inhibitors can be used, including benzothiazole or substituted benzothiazoles, pantoprazole sodium, benzotriazole (BTA), 2-mercaptobenzimidazole (2-MBI), sodium dodecylbenzenesulfonate (SDBS), SDBS and 2-MBI, 5-phenyl-2-amino-1,3,4-thiadiazole (APT), 5-(4-methoxyphenyl)-2-amino-1,3,4-thiadiazole (AMPT), 1-(p-tolyl)-4 1-Methylimidazole, 1-phenyl-4-methylimidazole, 4-methyl-5-hydroxymethylimidazole, 2-mercaptobenzimidazole (MBI) and KI, 5-methyl-2,4-dihydropyrazole-3-one (MHPO), 5-methyl-2-phenyl-2,4-dihydropyrazole-3-one (MPPO), cycloazolol, 1-phenyl-3-hydroxy-1,2,4-triazole, nitroxytetrazolium chloride (NTBC), thiols, amino acids, and Schiff bases. In some embodiments, at least one corrosion inhibitor comprises benzothiazole or a substituted benzothiazole.

[0048] In addition to the components listed above, the reaction mixture may include a variety of optional materials. A particularly suitable material is the solvent. Using a solvent in the reaction mixture helps to mix the components, thereby promoting the reaction. Examples of suitable solvents include hydrocarbon solvents, such as alkane-based solvents and aromatic solvents. Suitable alkane-based solvents include hexane, heptane, and petroleum ether. Examples of suitable aromatic solvents include toluene and xylene. If a solvent is used, it is typically removed during or before the solidification reaction is complete.

[0049] Various formulations of the reaction mixture are suitable. In some embodiments, the reaction mixture includes a siloxane tackifying resin, a corrosion inhibitor, and a solvent. Exemplary formulations include: At least one vinyl-functionalized siloxane, ranging from 60% to 70% by weight; 0.5% to 2% by weight of at least one hydrogen-functionalized siloxane; At least one hydrogenation silylation catalyst, ranging from 0.005 wt% to 0.012 wt%. At least one siloxane tackifying resin, comprising 30% to 38% by weight; and At least one corrosion inhibitor, ranging from 0.1% to 1.5% by weight; The percentage by weight (%) refers to the dry weight of 100 parts by weight of the total reaction mixture. The reaction mixture may also contain at least one solvent. One or more components of the composition may be provided by dissolving in a solvent and / or additional solvents may be added.

[0050] As described above, the corrosion-resistant adhesive composition of this disclosure possesses a variety of desirable properties. The components described above are mixed to form a reaction mixture, and the reaction mixture is cured to form a corrosion-resistant siloxane pressure-sensitive adhesive. After curing in layer form, the siloxane adhesive exhibits a stable modulus over a temperature range between approximately -30°C and 70°C, as measured by DMA (Dynamic Mechanical Analysis), and the cured adhesive layer has a shear storage modulus not exceeding 0.2 MPa at a frequency of 1 Hz. The cured siloxane adhesive layer is optically transparent and corrosion-resistant after lamination. Corrosion resistance is defined as a change in resistance of less than 10% after the cured siloxane adhesive layer is laminated onto a silver nanowire film and aged at 65°C / 90% relative humidity for 500 hours. In some embodiments, the cured siloxane adhesive layer is even more corrosion-resistant, such that after lamination of the cured siloxane adhesive layer onto a silver nanowire film, the change in resistance of the silver nanowire film is less than 10% after aging at 85°C / 85% relative humidity for 500 hours.

[0051] In addition to these properties, the cured siloxane adhesive also exhibits desirable dielectric constant characteristics. In some embodiments, the cured siloxane adhesive layer has a dielectric constant of less than or equal to 2.70 when measured at 100 kHz, and the dielectric constant is consistent, meaning that the dielectric constant measured at different frequencies is within 0.1 of the value measured at 100 kHz. Not only is the dielectric constant consistent, but it is also stable, meaning that when the adhesive is aged at 65°C / 90% relative humidity for 500 hours, the change in dielectric constant relative to the original value is less than 0.1.

[0052] This document also discloses laminated articles. In some embodiments, the laminated article includes a first substrate having a first main surface and a second main surface, an adhesive layer disposed on at least a portion of the second main surface of the first substrate, and a second substrate having a first main surface and a second main surface, wherein the first main surface of the second substrate is disposed on the adhesive layer. The adhesive layer is a corrosion-resistant siloxane pressure-sensitive adhesive as described above. The adhesive layer comprises a siloxane adhesive prepared from a reaction mixture, the reaction mixture comprising: At least one vinyl-functionalized siloxane; At least one hydrogen-functionalized siloxane; At least one hydrogenation silylation catalyst; At least one siloxane tackifying resin; and At least one corrosion inhibitor.

[0053] After the reaction mixture was cured in layer form, the siloxane binder exhibited a stable modulus in a temperature range between approximately -30°C and 70°C, as measured by DMA (Dynamic Mechanical Analysis). The cured binder layer had a shear storage modulus not exceeding 0.2 MPa at a frequency of 1 Hz. Furthermore, after laminating the cured siloxane binder layer onto a silver nanowire film, the silver nanowire film showed a resistance change of less than 10% after aging at 65°C / 90% relative humidity for 500 hours. The cured siloxane binder layer was also optically transparent. The reaction mixture and the binder layer prepared therefrom are described in detail above.

[0054] This document discloses a variety of laminated articles. In some embodiments, the laminated article is a transfer tape, other laminated articles are intermediate articles, and still other laminated articles are optical structures. Each of these laminated articles is described below.

[0055] The laminated article includes a first substrate and a second substrate. Depending on the type of laminated article, various substrates are suitable. In some embodiments, the laminated article is a transfer tape. In these articles, the first substrate and the second substrate are release liner. The transfer tape is well understood in the art to be a self-supporting adhesive layer that can be laminated to a substrate surface to prepare an additional laminated article.

[0056] Release liner is well known in the adhesives industry. Exemplary release liner includes those made of paper (e.g., kraft paper) or polymeric materials (e.g., polyolefins such as polyethylene or polypropylene, ethylene vinyl acetate, polyurethane, polyesters such as polyethylene terephthalate, etc., and combinations thereof). At least some release liner is coated with a release agent layer, such as silicone, hydrocarbon polymer, fluorinated silicone material, or fluorocarbon material. Particularly suitable release liner includes the FSD5 and SS1A release liner available from NIPPA Corporation.

[0057] In other embodiments, the laminated article is an intermediate article. Intermediate articles are those used to form the final article. In intermediate articles, the first substrate is the outer layer of the flexible display. Various flexible displays are suitable, such as OLEDs (organic light-emitting diodes), computer monitors, TVs, mobile phones, and small displays (in automobiles, appliances, wearable devices, electronic devices, etc.). A flexible electronic display is a display in which the display can be freely bent without breaking or fracturing. The outer layer of a flexible display is typically a polymer layer.

[0058] In intermediate product embodiments, the adhesive layer can be laminated to the surface of a first substrate, or the reaction mixture for forming the adhesive layer can be disposed on the surface of the first substrate, and the adhesive layer can be formed on the first substrate surface. In these embodiments, the second substrate is a release liner. The release liner is removed from the adhesive layer, and the substrate is laminated to the exposed adhesive surface to form the final article. An advantage of forming intermediate products is that they can be formed in one location or at a time, and the final article can be prepared in different locations or at different times.

[0059] In other embodiments, the laminated article has an optical structure. In these articles, the first substrate and the second substrate are optical substrates. The optical substrates can be flexible or rigid, and typically at least one optical substrate is flexible. The optical substrate is a substrate that produces optical effects. These optical effects include visible light transmission, visible light absorption, visible light reflection, or refraction, etc. Typically, the optical substrate is optically transparent.

[0060] Examples of flexible substrates include polymer films and copolymer films. Polymer films or copolymer films can be prepared from polyolefins, polyesters, polyurethanes, PENs, polyimides, or blends of these materials. Examples of rigid substrates include glass plates or other optically transparent materials, such as polycarbonate (PC) or polymethyl methacrylate (PMMA).

[0061] To utilize the corrosion-resistant properties of the adhesive disclosed herein, typically at least one of the first and second substrates comprises a silver nanowire film. Typically, the silver nanowire film comprises a network of interconnected nanowires on a polymer film or copolymer film substrate. The film substrate may be prepared from polyolefins, polyesters, polyurethanes, PENs, polyimides, or blends of these materials. The nanowires may be partially or completely encapsulated within an additional polymeric adhesive or resin layer.

[0062] exist Figure 1 An embodiment of the article of manufacture disclosed herein is shown. Figure 1 In this embodiment, article 100 includes a base layer 110 having sublayers 111 and 112. Sublayer 111 is a film layer, and sublayer 112 is a layer of silver nanowires dispersed in an adhesive. An adhesive layer 120 is disposed on sublayer 112 and includes a cured siloxane pressure-sensitive adhesive as described in detail above. A second base layer (not shown) may be disposed on adhesive layer 120.

[0063] This document also discloses a method for preparing a laminated article. In some embodiments, the method for preparing a laminated article includes providing a first substrate having a first main surface and a second main surface; providing a reaction mixture for preparing a siloxane adhesive or providing a siloxane adhesive layer; disposing the reaction mixture or the siloxane adhesive layer on at least a portion of the second main surface of the first substrate; if the reaction mixture is disposed on the second main surface of the first substrate, curing the reaction mixture to form the siloxane adhesive layer; providing a second substrate having a first main surface and a second main surface; and disposing the first main surface of the second substrate on the siloxane adhesive layer.

[0064] As described in detail above, the reaction mixture for preparing siloxane adhesives comprises: At least one vinyl-functionalized siloxane; At least one hydrogen-functionalized siloxane; At least one hydrogenation silylation catalyst; At least one siloxane tackifying resin; and At least one corrosion inhibitor.

[0065] The reaction mixture may further contain at least one solvent. If a solvent is present, the method further includes a drying step to remove the solvent. Typically, the solvent is removed simultaneously with the curing step or before the curing step. Depending on the nature of the solvent, drying may include heating to a high temperature, such as by placing the article in an oven. In some embodiments, drying is carried out at a temperature between about 60°C and 160°C. The drying time may also vary depending on the nature of the solvent used and the drying temperature. Typically, the drying time is less than 10 minutes.

[0066] In some embodiments, the first substrate is a release liner and the second substrate is also a release liner. In these embodiments, the laminated article is a transfer tape as described above.

[0067] In other embodiments, the laminated article is an intermediate article. In these intermediate articles, the first substrate is the outer layer of the flexible display. Various flexible displays are suitable, such as OLEDs (organic light-emitting diodes), computer monitors, TVs, mobile phones, and small displays (in automobiles, appliances, wearable devices, electronic devices, etc.). A flexible electronic display is a display in which the display can be freely bent without breaking or fracturing. The outer layer of the flexible display is typically a polymer layer. In the intermediate laminated article, the second substrate is a release liner.

[0068] In some embodiments of the intermediate product, the reaction mixture is disposed on the outer layer of the flexible display, and the reaction mixture is cured to form a siloxane adhesive layer. In other embodiments of the intermediate product, a transfer tape as described above is laminated to the outer layer of the flexible display.

[0069] In other embodiments, the laminated article has an optical structure. In the optical structure, a first substrate and a second substrate are both optical substrates. In some embodiments, the second main surface of the first substrate is the outer layer of a flexible display. The second substrate can be a flexible or rigid optical substrate as described above. Typically, both the first and second substrates are optically transparent. The optical structure can be formed directly by placing a reaction mixture on the second main surface of the first substrate, curing the reaction mixture to form a siloxane adhesive layer, and placing the second substrate on the formed siloxane adhesive layer.

[0070] Alternatively, the optical structure can be formed by forming a transfer tape article as described above, laminating the transfer tape to a second main surface of the first substrate, removing a release liner from the transfer tape to expose a siloxane adhesive layer, and placing the second substrate on the exposed siloxane adhesive layer.

[0071] Example

[0072] These examples are for illustrative purposes only and are not intended to limit the scope of the appended claims. Unless otherwise specified, all parts, percentages, ratios, etc., in the examples and the remainder of the specification are by weight. Unless otherwise specified, all solvents and other reagents used were obtained from Sigma-Aldrich Chemical, Milwaukee, Wisconsin. The following abbreviations are used: cm = centimeter; mm = millimeter; g = gram; kg = kilogram; min = minute; h = hour. The terms "weight%", "by weight%", and "wt%" are used interchangeably.

[0073]

[0074] Test methods

[0075] Test Method 1: Dynamic Mechanical Analysis

[0076] Dynamic mechanical analysis (DMA) was performed using a DHR3 parallel plate rheometer (TA Instruments) to characterize the physical properties of each sample as a function of temperature. For each SiOCA, approximately 0.5 g of binder material (after removing the peelable and close-fitting side release liner) was centered between the 8 mm diameter parallel plates of the rheometer and compressed until the edges of the sample were uniform with the edges of the top and bottom plates. Tests were performed at a frequency of 1 Hz and 20% of the maximum strain using a temperature scan rate of 3 °C / min. Scans were performed from -60 °C to 120 °C. Although many physical parameters of the material are recorded during temperature decrease, the storage modulus (G'), loss modulus (G''), and loss tangent are of primary importance in the characterization of the homopolymers disclosed herein.

[0077] Test Method 2: SNW Compatibility Test

[0078] First, a 3-inch x 4-inch (8cm x 10cm) portion of each SiOCA (after removing the easily peelable side release liner) was laminated onto the SNW film, and then the back side of the SiOCA (after removing the adhering side release liner) was laminated onto the LCD glass. The laminated portions were placed in an autoclave oven set at 50°C / 5kg pressure for 20 minutes. The conductivity of the SNW was measured in non-contact mode using a Delcom 20J3 thin-film resistance meter. The initial surface resistance was recorded in ohms / square. The laminated samples were then placed in an oven at 65°C and 90% humidity for 120 hours, 240 hours, and 500 hours, and the conductivity measurements were recorded. The %R change was used to determine the compatibility level. After 500 hours, if the R% change was less than 10% compared to the initial value, good compatibility was considered.

[0079] Test method 3: Dielectric constant

[0080] Each SiOCA strip was cut into 2.5-inch x 7-inch (6 cm x 18 cm) pieces and equilibrated for 24 hours in a controlled environment (CTH) chamber at 23°C and 55% relative humidity. They were then laminated to a thickness of at least 300 micrometers and the close-fitting side release liner was replaced with an easy-peel liner for transfer to a dielectric measurement instrument.

[0081] Three repeating disks, each 40 mm in diameter, were cut from each OCA strip. Two brass disk electrodes were cleaned, and their thicknesses were measured to a resolution of 0.001 mm. One release liner was removed from the OCA disk, and the disk was laminated to the mirror-finished side of the electrode. A second release liner was removed, and the mirror side of the second electrode was placed on the exposed adhesive, thus pressing them firmly together. The total thickness of the brass / adhesive / brass interlayer was measured at five locations around the disk. Based on the electrode thickness and the average thickness of the interlayer, the OCA thickness was calculated, and this value was used to calculate the dielectric constant.

[0082] For measurement, each repeating disk with electrodes was placed in the sample holder of an LCR meter (Keysight E4980A) using 16048A test leads. Using a measurement signal level of 1V scan frequency within the range of interest, the LCR meter measured the capacitance (Cp) and dissipation factor (D) for each repeating disk. The dielectric constant was calculated from Cp and geometric parameters.

[0083] To measure the dielectric constant after accelerated aging, 2.5-inch x 7-inch (6 cm x 18 cm) SiOCA strips were cut after removing the easily peelable side release liner and placed in an oven at 65°C and 90% relative humidity for 500 hours. They were then removed and equilibrated in a CTH chamber at 23°C and 55% relative humidity for 24 hours. At this point, the strips were stacked to a thickness >300 micrometers, and the dielectric constant was measured using the same procedure as described above.

[0084] Test Method 4: Water Vapor Transport Rate (WVTR)

[0085] SiOCA samples were cut into 3.50-inch x 8-inch (9 cm x 20 cm) strips and laminated between two CELGARD membranes. Excess OCA was cut from the edges of each sample. A 1.5-inch (4 cm) wide strip was cut from the middle of the CELGARD stack and laminated to the viscous side of a PERMATRAN (W-type 1 / 50 G water vapor permeability, Mocon) instrument mask.

[0086] Wet the sponge in the instrument's bottom tray with deionized water. Spread the grease on the base plate and the flat area around the sponge indentation. Place the mask and laminated sample face down on the greased plate, with the non-sticky side of the mask facing the grease. Align the two plates and place them back into the PERMATRAN. Run the instrument at 40°C and near 100% relative humidity for at least 2 hours to ensure a steady-state WVTR value.

[0087] Examples Ex1-Ex3 and Comparative Examples CE-1 and CE-2

[0088] Organosilicon OCA preparations

[0089] All organosilicon OCA (SiOCA) formulations were prepared by mixing the materials listed in Table 2. HS, ACA, and Pt Cat were diluted in solvents listed in Table 1 before being mixed with other materials. All quantities listed in Table 2 are in grams. To prepare the SiOCA formulation, all components (except Pt Cat) were mixed in a 500 mL wide-mouth glass flask, and then the Pt catalyst was added and mixed into the solution. The flask was rolled for 10 to 20 minutes to ensure proper mixing of all components.

[0090] Coating and curing

[0091] Using a doctor blade coater, apply the SiOCA formulation described above to release liner-1 to a wet thickness of 16 mils (400 micrometers). Cur the coating in a solvent-rated oven at 120°C for 2 minutes. After curing the SiOCA, laminate release liner-2 onto the open side of the SiOCA using a soft rubber roller and light pressure. Liner-2 serves as the easy-peel side release liner, while liner-1 serves as the close-fitting side release liner.

[0092]

[0093] test

[0094] The rheological properties and silver nanowire compatibility of the cured OCA composition were tested according to the test methods described above. The data are shown in Tables 3 and 4 below.

[0095]

[0096] Comparing CE-1 with EX-1 and EX-2, it is clear that the addition of corrosion inhibitors significantly improves SNW compatibility. Acrylic adhesive-1 has been shown to have good compatibility with SNW. Surprisingly, SiOCAs such as EX-1 also achieve SNW compatibility, even though their WVTR is more than 7 times that of acrylate adhesive-1.

Claims

1. A corrosion-resistant adhesive composition, said corrosion-resistant adhesive composition comprising: A siloxane-based adhesive prepared from a reaction mixture, the reaction mixture comprising: At least one vinyl-functionalized siloxane; At least one hydrogen-functionalized siloxane; At least one hydrogenation silylation catalyst; At least one siloxane tackifying resin; and At least one corrosion inhibitor, After curing in the form of a layer, the siloxane adhesive, as measured by DMA (Dynamic Mechanical Analysis), has a stable modulus in a temperature range between approximately -30°C and 70°C. The cured adhesive layer has a shear storage modulus of no more than 0.2 MPa at a frequency of 1 Hz. Furthermore, after laminating the cured siloxane adhesive layer onto a silver nanowire film, the silver nanowire film exhibits a resistance change of less than 10% after aging at 65°C / 90% relative humidity for 500 hours. The cured siloxane adhesive layer is also optically transparent.

2. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one vinyl-functionalized siloxane is represented by formula 1: R1, R2, R3, and R4 are each independently selected from the group consisting of alkyl groups, aryl groups, and olefinic unsaturated groups; Each R5 is an alkyl group; Each X is an olefinic unsaturated group or an alkyl group; and n and m are integers, and at least one of m or n is not 0.

3. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one vinyl-functionalized siloxane is represented by formula 1: R1 is an olefinic unsaturated group; R2, R3, and R4 are each independently selected from the group consisting of alkyl or aryl groups; Each R5 group is an alkyl group; Each X is an alkyl group; and n and m are integers, and at least m is not 0.

4. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one hydrogen-functionalized siloxane is represented by formula 2: R1, R2, R3, and R4 are independently selected from the group consisting of alkyl groups, aryl groups, and hydrogen groups; Each R5 is an alkyl group; and n and m are integers, and at least one of m or n is not 0.

5. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one hydrogen-functionalized siloxane is represented by formula 2: R1 is a hydrogen group. R2, R3, and R4 are independently selected from the group consisting of alkyl or aryl groups; Each R5 is an alkyl group; and n and m are integers, and at least m is not 0.

6. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one hydrogenation silanization catalyst comprises a platinum catalyst.

7. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one siloxane tackifying resin is an MQ resin.

8. The corrosion-resistant adhesive composition according to claim 1, wherein the at least one corrosion inhibitor comprises benzothiazole or a substituted benzothiazole.

9. The corrosion-resistant adhesive composition according to claim 1, wherein after the cured siloxane adhesive layer is laminated onto the silver nanowire film, the change in resistance of the silver nanowire film is less than 10% after aging at 85°C / 85% relative humidity for 500 hours.

10. The corrosion-resistant adhesive composition of claim 1, wherein the cured siloxane adhesive layer has a dielectric constant of less than or equal to 2.70 when measured at 100 kHz, and wherein the dielectric constant is consistent, meaning that the dielectric constant measured at different frequencies is within 0.1 of the value measured at 100 kHz, and wherein the dielectric constant is stable, meaning that when the adhesive is aged at 65°C / 90% relative humidity for 500 hours, the change in the dielectric constant relative to the original value is less than 0.

1.

11. A laminated article, the laminated article comprising: A first substrate, the first substrate having a first main surface and a second main surface; An adhesive layer is disposed on at least a portion of the second main surface of the first substrate; as well as A second substrate having a first main surface and a second main surface, wherein the first main surface of the second substrate is disposed on the adhesive layer, wherein the adhesive layer comprises a siloxane adhesive prepared by a reaction mixture, the reaction mixture comprising: At least one vinyl-functionalized siloxane; At least one hydrogen-functionalized siloxane; At least one hydrogenation silylation catalyst; At least one siloxane tackifying resin; and At least one corrosion inhibitor, After curing in the form of a layer, the siloxane adhesive, as measured by DMA (Dynamic Mechanical Analysis), has a stable modulus in a temperature range between approximately -30°C and 70°C. The cured adhesive layer has a shear storage modulus of no more than 0.2 MPa at a frequency of 1 Hz. Furthermore, after laminating the cured siloxane adhesive layer onto a silver nanowire film, the silver nanowire film exhibits a resistance change of less than 10% after aging at 65°C / 90% relative humidity for 500 hours. The cured siloxane adhesive layer is also optically transparent.

12. The laminated article of claim 11, wherein the first substrate and the second substrate are release liner, and the laminated article is a transfer tape.

13. The laminated article of claim 11, wherein at least one of the first substrate and the second substrate is flexible, and at least one of the first substrate and the second substrate comprises silver nanowires in contact with the adhesive layer.

14. The laminated article according to claim 11, wherein the at least one vinyl-functionalized siloxane is represented by formula 1: R1 is an olefinic unsaturated group; R2, R3, and R4 are each independently selected from the group consisting of alkyl or aryl groups; Each R5 group is an alkyl group; Each X is an alkyl group; and n and m are integers, and at least m is not 0.

15. The laminated article according to claim 11, wherein the at least one hydrogen-functionalized siloxane is represented by formula 2: R1 is a hydrogen group. R2, R3, and R4 are independently selected from the group consisting of alkyl or aryl groups; Each R5 is an alkyl group; and n and m are integers, and at least m is not 0.

16. The laminated article of claim 11, wherein the at least one corrosion inhibitor comprises benzothiazole or a substituted benzothiazole.

17. The laminated article of claim 11, wherein the first substrate comprises the outer surface of an optical device, the second substrate comprises an optical substrate, and at least one of the first substrate or the second substrate comprises silver nanowires in contact with the adhesive layer.

18. A method for preparing a laminated article, the method comprising: A first substrate having a first main surface and a second main surface is provided; A reaction mixture for preparing a siloxane adhesive is provided, the reaction mixture comprising: At least one vinyl-functionalized siloxane; At least one hydrogen-functionalized siloxane; At least one hydrogenation silylation catalyst; At least one siloxane tackifying resin; and At least one corrosion inhibitor; Alternatively, a siloxane-based adhesive layer may be provided; The reaction mixture or the siloxane adhesive layer is disposed on at least a portion of the second main surface of the first substrate; If a reaction mixture is used, the reaction mixture is cured to form a siloxane-based adhesive layer; A second substrate having a first main surface and a second main surface is provided, and the first main surface of the second substrate is disposed on the siloxane adhesive layer.

19. The method of claim 18, further comprising a drying step during or after the curing of the reaction mixture.

20. The method of claim 18, wherein disposing the siloxane adhesive layer on at least a portion of the second main surface of the first substrate comprises a laminated adhesive layer.

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