Electronic article having an interlayer adhesive layer with damping / shock absorption function

Abstract

An electronic article having an interlayer adhesive layer having a tanδ peak temperature of less than 35°C and a peak tanδ value of greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system. In the electronic article of the present invention, the interlayer adhesive layer provides impact resistance to the electronic article as a damping / shock absorbing layer and is disposed between two functional layers to bond or assemble the two functional layers. Preferably, the electronic article of the present invention is a display device.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) none.

[0002] FIELD OF THE INVENTION The present invention relates to an electronic article having an interlayer adhesive layer that bonds / assembles a functional layer having a damping / shock absorbing function. In particular, the present invention relates to an electronic article (including an electronic device, equipment, component / module, and unit) having an interlayer adhesive layer that exhibits specific viscoelastic properties in tan δ curve measurement and a damping / buffering functional layer with a bonding / assembly function. This electronic article provides impact resistance to the electronic article via the interlayer adhesive layer as a damping / shock absorbing layer, and is useful in display device applications having a structure in which a transparent display unit is directly bonded to or assembled with another functional unit. Preferably, the interlayer adhesive layer is a silicone-based pressure-sensitive adhesive layer. [Background technology]

[0003] Recent electronic articles (electronic devices, equipment, components / modules, and units; typically, LED or OLED display devices and their modules) are composed of multiple functional layers, with a structure in which a film composed of multiple layers, including electrode layers and display layers, is sandwiched between substrates. To construct / assemble such electronic articles, interlayer adhesive layers (or layers) are disposed between the functional layers as "assembly layers" for bonding / assembling the functional layers in the electronic article. In particular, silicone-based pressure-sensitive adhesive layers (PSA) have superior electrical insulation, heat resistance, cold resistance, and adhesion to various substrates compared to acrylic- or rubber-based pressure-sensitive adhesive compositions. Taking advantage of the above-mentioned characteristics of polysiloxane pressure-sensitive adhesives, as well as their ability to achieve high transparency as needed, their application in the fields of advanced electronic materials and display elements such as smart devices has been explored in recent years. Furthermore, although Patent Documents 1 to 4 disclose the characteristics of the tan δ curves of silicone-based PSAs, they do not disclose or suggest the use of a single silicone-based PSA layer as an interlayer assembly layer with damping / shock absorption functions in electronic articles such as display devices.

[0004] Meanwhile, to provide electronic articles with impact resistance and improve their mechanical and electrical reliability, conventional designs of electronic articles (e.g., LED or OLED display devices used in automotive displays, foldable displays, etc.) typically employ a foam tape (e.g., PU foam, PE foam, or acrylic foam) or other interlayer damping or shock-absorbing layer sandwiched between two adhesive layers to bond other functional layers (e.g., a display layer and an electrode layer) as follows: [display layer / first adhesive layer / damping or shock-absorbing layer / second adhesive layer / electrode layer]. Display electronic devices, particularly smartphones with OLED displays, are becoming increasingly thinner, making interlayer damping or shock absorption increasingly important for protecting the screen from cracks during drop tests. For example, Patent Documents 5 and 6 propose the use of foam sheets with silicone-based PSA layers or damping laminates using silicone-based PSA layers, but the market demands better damping or shock-absorbing layers. In addition, because foam layers or other such damping or shock-absorbing layers require adhesive layers on both sides to bond / assemble to other functional layers, multiple lamination processes are required to build electronic articles (e.g., LED or OLED type display devices), and the electronic articles tend to be thick and heavy due to the internal multi-layer damping or shock-absorbing layers. Therefore, there is a need in the market for better and improved assembly layers to achieve thinner and lighter electronic articles with better reliability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018149720(A1) [Patent Document 2] International Publication No. 2018149718(A1) [Patent Document 3] International Publication No. 2018149717(A1) [Patent Document 4] JP 2003313515(A) [Patent Document 5] JP 2019167484(A) [Patent Document 6] JP-A No. 04-214341(A) Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been devised to solve the above-mentioned problems, and its object is to provide an electronic article having a thinner damping or shock-absorbing layer that provides the electronic article with impact resistance and improves mechanical and electrical reliability, and in which a functional layer is firmly bonded or assembled within the electronic article. Another object of the present invention is to provide a simplified manufacturing process for the electronic article that does not require multiple lamination processes to build the interlayer damping or shock-absorbing layer. A further object of the present invention is to provide the use of an interlayer adhesive layer in the electronic article as the damping / shock-absorbing layer, and the electronic article does not have any additional foam layer or damping / shock-absorbing layer. [Means for solving the problem]

[0007] The present inventors have arrived at the present invention as a result of extensive research into the above-mentioned problems. Specifically, one object of the present invention is achieved by an electronic article having an interlayer adhesive layer in which the temperature at the tan δ peak is less than 35°C and the tan δ value at the peak is greater than 1.0. When measuring the tan δ curve for the interlayer adhesive layer, if the tan δ value is defined as the absolute value of the temperature range in which it exceeds 0.5, the width of the tan δ peak of the interlayer adhesive layer is preferably narrower than 90°C. In the present invention, the interlayer adhesive layer is preferably a pressure-sensitive silicone adhesive layer obtained by curing a silicone-based pressure-sensitive adhesive-forming composition containing the following components (A) to (D): (A) a linear organopolysiloxane having an average of more than one alkenyl group per molecule; (B) an organopolysiloxane resin having a total content of hydroxyl groups and hydrolyzable groups of 9 mol % or less relative to all silicon atoms in the molecule; (C) an organohydrogenpolysiloxane having at least two Si-H bonds in one molecule, and (D) Hydrosilylation reaction catalyst.

[0008] The electronic article of the present invention includes an interlayer adhesive layer that acts as a damping / shock absorbing layer to provide impact resistance to the electronic article and is disposed between the two functional layers to bond or assemble the two functional layers. Preferably, the electronic article of the present invention is a display device.

[0009] The present invention also provides a process for manufacturing an electronic article of the present invention, comprising assembling or bonding at least two functional layers with an interlayer adhesive layer having a tan δ peak temperature of less than 35°C and a tan δ peak value of greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system.

[0010] The present invention also provides the use of an interlayer adhesive layer as a damping / shock absorbing layer in an electronic article, wherein the interlayer adhesive layer has a temperature at tan δ peak of less than 35°C and a tan δ value at the peak of greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system. [Effects of the Invention]

[0011] The interlayer adhesive layer has sufficient adhesiveness for practical use to bond or assemble functional layers in the electronic article of the present invention, and also serves as a damping / impact-absorbing layer to provide impact resistance to the electronic article, allowing the construction of electronic articles with thinner and lighter laminate structures without using a separate damping or impact-absorbing layer other than the interlayer adhesive layer of the present invention. The electronic article of the present invention exhibits a better damping or impact-absorbing layer that provides impact resistance to the electronic article and improves its mechanical and electrical reliability. In addition, because the interlayer adhesive layer in the electronic article of the present invention can be a single coating layer that has both the assembly / joining layer function and the damping / impact-absorbing layer function, the manufacturing process for the electronic article of the present invention can be a simplified process that does not require a multi-step lamination / coating process to construct the interlayer damping or impact-absorbing layer. [Brief explanation of the drawings]

[0012] [Figure 1] The results of a ball drop test for a laminate using the interlayer adhesive layer obtained in Example 7 are shown below, and no cracks were observed at the ball contact points. [Figure 2] The results of a ball drop test for a laminate using the interlayer adhesive layer obtained in Comparative Example 1 are shown, and clear cracks were observed at the ball contact points. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Definition of viscoelastic properties for measured tan δ curves of adhesive layers] As used herein, the temperature at the tan δ peak, the temperature range (including the absolute value between two points of temperature on the measured tan δ curve), the tan δ value, and other viscoelastic properties associated with the measured tan δ curve for an interlayer adhesive layer refer to those measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system.

[0014] [Structure of electronic items] As used herein, the term "electronic article" includes electronic devices, electronic equipment, and electronic components / modules / units. First, the structure of the electronic article of the present invention will be described. The electronic article is characterized by having at least one interlayer adhesive layer whose tan δ peak temperature is less than 35°C and whose tan δ value at the peak is greater than 1.0. In the electronic article, the interlayer adhesive layer is disposed between the two functional layers to bond or assemble them. Preferably, the electronic article is an LED or OLED display device or module thereof, which is composed of multiple functional layers, and has a structure in which a laminate of multiple functional layers, including electrode layers and display layers, is sandwiched between substrates, and the functional layers are bonded or assembled by the interlayer adhesive layer. In a preferred embodiment of the electronic article of the present invention, the interlayer adhesive layer is disposed between two functional layers, at least one of which may be substantially transparent. Furthermore, since the interlayer adhesive layer has both the function of an assembly / joining layer and the function of a damping / shock absorbing layer, the electronic article of the present invention does not require an additional interlayer damping / shock absorbing layer disposed between the two functional layers. Due to this bifunctional feature of the interlayer adhesive layer, electronic articles can be constructed through the present invention without using any additional interlayer damping / shock absorbing layer other than the interlayer adhesive layer between the two functional layers.

[0015] Most preferably, the electronic article of the present invention is an LED or OLED display device and module thereof, having a structure in which a display unit is directly bonded or assembled to other functional units using an interlayer adhesive layer, which is a single adhesive / assembly layer sandwiched between the units in the display device. The display device of the present invention can be designed to be substantially free of interlayer damping / shock absorbing layers except for the interlayer adhesive layer (i.e., omitting thick, multi-layer damping / shock absorbing layers from the device), so that the overall thickness of the display can be thinner and lighter than conventional devices.

[0016] The surface shape of such display devices may be curved or bent rather than flat. Examples include various flat panel displays (FPDs), as well as curved displays and curved transmission screens used in automobiles (including electric vehicles) and aircraft. Furthermore, these display devices can display icons for executing functions or programs, notification indicators for emails and programs, and operation buttons for various devices such as car navigation devices, speaker membranes, audio devices, and air conditioner devices on their screens or displays. They also have touch panel functionality that allows input operations to be added by touching these icons, notification indicators, or operation buttons with a finger. Display devices such as CRT displays, liquid crystal displays, plasma displays, organic electroluminescence (EL) displays, inorganic electroluminescence (EL) displays, LED displays, surface-emitting field displays (SEDs), and field-emission displays (FEDs), as well as devices such as touch panels using these display devices.

[0017] [Function, thickness, and viscoelastic properties of the interlayer adhesive layer] In the electronic article of the present invention, the interlayer adhesive layer, as a single layer with dual functional properties, functions as both an assembly / joining layer and a damping / shock absorbing layer. That is, the interlayer adhesive layer has sufficient adhesion to bond or assemble two functional layers within the electronic article, and also functions as a damping / shock absorbing layer to provide impact resistance to the electronic article, improving its mechanical and electrical reliability. The thickness of the interlayer adhesive layer is not limited and can be optimized by those skilled in the art according to the requirements, structure, and size of the electronic article. However, the preferred thickness of the interlayer adhesive layer is in the range of 1 to 1000 μm, more preferably 10 to 500 μm, and most preferably 50 to 300 μm. If the thickness is below the lower limit, the adhesive strength and damping / shock absorption may be insufficient to achieve the objectives of the present invention. On the other hand, if the thickness exceeds the upper limit, the electronic article having a thick interlayer adhesive layer cannot be made thinner and lighter.

[0018] To achieve the bifunctional characteristics in the interlayer adhesive layer for the electronic article of the present invention, the interlayer adhesive layer satisfies the temperature at tan δ peak of less than 35°C, less than 30°C, less than 25°C, less than 20°C, or less than 15°C, and the tan δ value at the peak is greater than 1.0, greater than 1.2, greater than 1.5, or greater than 1.7. Preferably, the tan δ value at the peak is in the range of 1.00 to 4.00, 1.00 to 2.00, or 1.00 to 1.50, and the temperature at tan δ peak is located at -70°C to 25°C, -60°C to 20°C, -50°C to 15°C, -40°C to 10°C, or -20°C to 5°C. Furthermore, to achieve better damping / shock absorption properties in the interlayer adhesive layer, when the tan δ value is defined as the absolute value of the temperature range over which tan δ exceeds 0.5, the width of the tan δ peak in the interlayer adhesive layer is narrower than 90°C, 80°C, 70°C, 60°C, or 50°C. For example, when measured at 1 Hz using a dynamic mechanical analysis rheometer using a parallel plate measurement system, when the tan δ value exceeds 0.5 in a temperature range of -60°C to 25°C and the tan δ peak is located within that temperature range, the width of the tan δ peak in the interlayer adhesive layer is defined as 85°C as the absolute value of that temperature range. Similarly, when the tan δ value exceeds 0.5 in a temperature range of -50°C to 15°C and the tan δ peak is located within that temperature range, the width of the tan δ peak in the interlayer adhesive layer is defined as 65°C as the absolute value of that temperature range. Preferably, the width of the tan δ peak in the interlayer adhesive layer is in the range of 50 to less than 90°C to achieve better damping / shock absorption properties in the interlayer adhesive layer. On the other hand, if the width of the tan δ peak in the interlayer adhesive layer is 90°C or more, the shape of the tan δ peak is too broad to achieve sufficient damping / shock absorption properties with sufficient adhesive strength to bond / assemble functional layers in electronic articles. Most preferably, in the present invention, the tan δ curve of the interlayer adhesive layer satisfies the following condition when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system: i) the temperature at the tan δ peak (preferably, the tan δ value at the peak in the range of 1.00 to 2.50) is located at -70°C to 25°C; ii) The width of the tan δ peak, as defined by the absolute value of the temperature range in which the value of tan δ exceeds 0.5, is in the range of 50°C to less than 90°C.

[0019] In the present invention, the material of the interlayer adhesive layer is not particularly limited, and any type of adhesive material can be used in the present invention as long as the interlayer adhesive layer satisfies the viscoelastic properties in a tan δ curve measurement. For example, at least one selected from a silicone-based pressure-sensitive adhesive (PSA), an acrylic or rubber-based adhesive, and a polyurethane-based adhesive can be used as an interlayer adhesive layer having both an assembly / bonding layer function and a damping / impact-absorbing layer function in the electronic article of the present invention. Silicone-based pressure-sensitive adhesive (PSA) layers have excellent electrical insulation, heat resistance, cold resistance, and adhesion to various adherends in electronic articles, so silicone-based PSA layers are preferably exemplified as the interlayer adhesive layer in the electronic article of the present invention.

[0020] [Silicone-based PSA-forming composition] In one embodiment of the present invention, the interlayer adhesive layer used in the electronic article of the present invention can be obtained by curing a silicone-based pressure-sensitive adhesive-forming composition. This composition rapidly cures via a curing reaction that includes a hydrosilylation reaction to form a pressure-sensitive adhesive layer having sufficient adhesion for practical use and the above-mentioned viscoelastic properties related to the measured tan δ curve of the adhesive layer. The components of the composition, the range of organopolysiloxane resins, the mass ratio of organopolysiloxane resin to linear organopolysiloxane, and the characteristics of the pressure-sensitive adhesive layer are described below.

[0021] As described above, the organopolysiloxane composition of the present invention cures via a hydrosilylation reaction to form a pressure-sensitive adhesive layer (having a certain adhesive strength). This composition uses an organopolysiloxane resin in which the total content of hydroxyl groups and hydrolyzable groups relative to all silicon atoms in the molecule is 9 mol % or less, and the blending range of the organopolysiloxane resin relative to the linear organopolysiloxane (containing alkenyl groups) that functions as the base component is within a specific range.

[0022] In one embodiment of the present invention, the organopolysiloxane composition for obtaining the silicone-based PSA layer applied to the present invention comprises components (A) to (E). (A) a linear organopolysiloxane having an average of more than one alkenyl group per molecule; (B) an organopolysiloxane resin having a total content of hydroxyl groups and hydrolyzable groups of 9 mol % or less relative to all silicon atoms in the molecule; (C) an organohydrogenpolysiloxane having at least two Si-H bonds in the molecule, and (D) Hydrosilylation reaction catalyst.

[0023] Furthermore, in a further embodiment of the present invention, the silicone-based PSA-forming composition may further contain (A') a linear organopolysiloxane that does not contain a carbon-carbon double bond-containing reactive group in the molecule.

[0024] Since the composition contains a hydrosilylation reaction catalyst, it may further contain a cure retarder (E) from the viewpoint of ease of handling, and may further contain other additives within the scope of the present invention. If necessary, at least one tetraalkoxysilane or tetraalkoxysilane prepolymer may be blended as a fixing additive to improve the adhesive strength without affecting the rheological / viscoelastic properties.

[0025] In the present invention, component (A) is a linear (i.e., chain) organopolysiloxane having an average of more than one alkenyl group per molecule, preferably 1.5 or more alkenyl groups per molecule, and more preferably 2.0 or more alkenyl groups per molecule. In some embodiments according to the present invention, the average number of alkenyl groups per molecule may be in the range of 1.01 to 5.0, 1.01 to 4.0, 1.01 to 3.0, 1.01 to 2.0, 1.01 to 1.5, 1.5 to 5.0, 1.5 to 4.0, 1.5 to 3.0, 1.5 to 2.0, 2.0 to 5.0, 2.0 to 4.0, 2.0 to 3.0, 3.0 to 5.0, 3.0 to 4.0, or 4.0 to 5.0. Examples of the alkenyl group in the organopolysiloxane of component (A) include alkenyl groups having 2 to 10 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl, with vinyl and hexenyl being particularly preferred. The bonding positions of the alkenyl groups in component (A) include the molecular chain terminals and / or molecular side chains. Component (A) may be a single component or a mixture of two or more different components.

[0026] Examples of silicon-bonded organic groups other than alkenyl groups in the organopolysiloxane of component (A) include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl, with methyl and phenyl groups being particularly preferred.

[0027] In the present invention, component (A) has a linear organopolysiloxane molecular structure, unlike component (B). For example, component (A) is preferably linear or partially branched linear, and may also contain a partially cyclic three-dimensional network. Preferably, the main chain of the organopolysiloxane is composed of repeating diorganosiloxane units (i.e., -SiO 2 / 2Preferably, the diorganopolysiloxane is a linear or branched diorganopolysiloxane consisting of a triorganosiloxy unit (T or D unit) and both molecular chain terminals are blocked with triorganosiloxy groups. The siloxane units that provide the branched organopolysiloxane are T units or Q units, which will be described later.

[0028] Component (A) may be in the form of an oil or a crude rubber-like substance at room temperature, and preferably has a viscosity of 50 mPa·s or greater, particularly 100 mPa·s or greater, at 25° C. In particular, when the linear organopolysiloxane composition according to the present invention is a solvent-based composition, at least a portion of component (A) is (A1) a crude rubber-like alkenyl group-containing organopolysiloxane having a viscosity of 100,000 mPa·s or greater at 25° C. or a plasticity, measured in accordance with the method specified in JIS K6249 (the value obtained by applying a load of 1 kgf to a 4.2 g spherical sample at 25° C. for 3 minutes, reading the thickness to the nearest 1 / 100 mm, and multiplying the result by 100), in the range of 50 to 200, preferably 80 to 200, and more preferably 100 to 200.

[0029] To prevent poor contact, it is preferable to reduce or remove volatile or low-molecular-weight siloxane oligomers (e.g., octamethyltetracyclosiloxane (D4), decamethylpentacyclosiloxane (D5), etc.) in the organopolysiloxane alkenyl groups. The amount can be designed as desired, but must be less than 1% by mass of the total component (A), less than 0.1% by mass for each siloxane oligomer, and, if necessary, reduced to near the detection limit.

[0030] There are no particular restrictions on the content of alkenyl groups in component (A1), but the content of vinyl (CH2=CH) moieties in the alkenyl groups in component (A1) (hereinafter referred to as the "vinyl content") is preferably within the range of 0.005 to 0.400 mass%, more preferably within the range of 0.005 to 0.300 mass%, and in some cases particularly preferably within the range of 0.005 to 0.200 mass%.

[0031] In some embodiments of the present invention, a component (A) having a lower viscosity than component (A1) can also be used as component (A) of the present invention. Specifically, an alkenyl group-containing organopolysiloxane (A2) having a viscosity of less than 100,000 mPa s at 25°C can be used. Note that, apart from the viscosity, examples of component (A2) are the same as those of component (A1).

[0032] In the present invention, it is preferred that 50 mass % or more of component (A) is component (A1), a high-degree-of-polymerization alkenyl-containing organopolysiloxane, and it is particularly preferred that 75 to 100 mass % is component (A1). That is, when component (A) of the present invention is a combination of component (A1) (= a high-degree-of-polymerization alkenyl-containing organopolysiloxane) and component (A2) (= a low-degree-of-polymerization alkenyl-containing organopolysiloxane), the mass ratio of component (A1) to component (A2) is 50:50 to 100:0, preferably 75:25 to 100:0, and more preferably 75:25 to 90:10.

[0033] In the present invention, the organopolysiloxane resin of component (B) is an adhesion-imparting component that imparts adhesion to a substrate, and a low-temperature storage modulus and a practical range of adhesive strength are simultaneously achieved by using a mixture of organopolysiloxane resins in a specific ratio relative to component (A). More specifically, component (B) is an organopolysiloxane resin with a low average molecular weight, and the content of hydroxyl groups and hydrolyzable groups is reduced, making it less likely for hydrolysis and polymerization reactions to occur between components (B). By selectively using an organopolysiloxane resin with a low average molecular weight, the pressure-sensitive adhesive layer, which is the cured product, can achieve a desired storage modulus and a practical range of adhesive strength.

[0034] Specifically, component (B) is an organopolysiloxane resin in which the total content of hydroxyl groups and hydrolyzable groups relative to the total number of silicon atoms in the molecule is 9 mol% or less, 8 mass% or less, or 6 mass% or less. Component (B) according to the present invention has a total content of hydroxyl groups and hydrolyzable groups in the molecule that is 9 mol% or less, relative to the total number of silicon atoms in the organopolysiloxane resin molecule, and preferably 7 mol% or less, relative to the total number of silicon atoms in the molecule. The content of hydroxyl groups and hydrolyzable groups in component (B) can be expressed by converting all of these functional groups into hydroxyl groups. In this case, when the mass % is calculated assuming that all hydrolyzable groups other than hydroxyl groups in the organopolysiloxane resin molecule are hydroxyl groups (OH), the total content of the hydroxyl groups and hydrolyzable groups can be expressed so that the content of hydroxyl groups and these hydrolyzable groups converted to hydroxyl groups in the organopolysiloxane resin molecule is 2.0 mass % or less, 1.6 mass % or less, 1.5 mass % or less, or 1.2 mass % or less. Hydroxyl groups or hydrolyzable groups are groups directly bonded to silicon atoms, such as T units or Q units, among the siloxane units in the resin structure described below, and are groups obtained by hydrolyzing silane or silane derivatives. Therefore, the content of hydroxyl groups or hydrolyzable groups can be reduced by hydrolyzing the synthesized organopolysiloxane resin with a silylating agent such as trimethylsilane.

[0035] In component (B), if the amount of hydroxyl groups or hydrolyzable groups exceeds the upper limit, a condensation reaction between organopolysiloxane resin molecules proceeds, and a high-molecular-weight organopolysiloxane resin structure is likely to form in the cured product. Such high-molecular-weight organopolysiloxane resins tend to impair the curability of the entire composition, which may result in insufficient curing of the composition at low temperatures, and the resulting pressure-sensitive adhesive layer may not have a storage modulus sufficient for practical use.

[0036] In the present invention, component (B) is an organopolysiloxane resin having a three-dimensional structure. For example, RSiO 2 / 2 Units (D units) and RSiO 3 / 2units (T units) (wherein each R independently represents a monovalent organic group) and the content of hydroxyl groups or hydrolyzable groups is within the above range; a resin consisting only of T units and the content of hydroxyl groups or hydrolyzable groups is within the above range; RSiO 1 / 2 Units (M units) and SiO 4 / 2 The resins include those consisting of units (Q units) and having a hydroxyl group or hydrolyzable group content within the above range. 1 / 2 Units (M units) and SiO 4 / 2 A resin (also called an MQ resin) consisting of units (Q units) and having a total content of hydroxyl groups and hydrolyzable groups of 0 to 7 mol % relative to all silicon atoms in the molecule (when all of these functional groups have been converted to hydroxyl groups, the total content is preferably in the range of 0.0 to 1.6 mass %) is preferably used.

[0037] The monovalent organic group for R is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a cycloalkyl group having 6 to 10 carbon atoms, a benzyl group, a phenylethyl group, a phenylpropyl group, etc. In particular, it is preferable that 90 mol % or more of R are alkyl groups having 1 to 6 carbon atoms or phenyl groups, and it is particularly preferable that 95 to 100 mol % of R are methyl groups or phenyl groups.

[0038] Preferably, component (B) is (B1)RSiO 1 / 2 Units and SiO 4 / 2 The organopolysiloxane resin or mixture thereof is essentially composed of RSiO units, in which R is a monovalent organic group and 90 mol % or more of the R are alkyl groups having 1 to 6 carbon atoms or phenyl groups. 1 / 2 Units (M units) and SiO 4 / 2In the case of a resin composed of M units and Q units, the molar ratio of M units to Q units is preferably 0.5 to 2.0. This is because a molar ratio of less than 0.5 may result in a decrease in adhesive strength to the substrate, while a molar ratio of more than 2.0 may result in a decrease in cohesive strength of the material constituting the adhesive layer. Component (B) may also contain D units and / or T units to the extent that the properties of the present invention are not impaired. Furthermore, to prevent poor contact and the like, the amount of low-molecular-weight siloxane oligomers in these organopolysiloxane resins may be reduced or removed.

[0039] In the present invention, the weight-average molecular weight (Mw) of the organopolysiloxane resin that functions as component (B) is not limited, and at least one organopolysiloxane resin having a specific Mw or a mixture of two or more organopolysiloxane resins having different Mws can be used as component (B). From a practical standpoint, the Mw of component (B) determined by gel permeation chromatography (GPC) relative to standard polystyrene is 500 to 20,000 (g / mol), preferably 1,000 to 17,500 (g / mol), and most preferably 2,000 to 16,500 (g / mol).

[0040] [Mass ratio of component (B) to component (A)] The pressure-sensitive adhesive layer-forming organopolysiloxane composition according to the present invention is characterized in that the mass ratio of component (B) (organopolysiloxane resin) to component (A) (linear reactive siloxane component) is within a specific range. The mass ratio of component (B) to component (A), in combination with component (D) as a fixed additive, is within the range of 0.5 to 3.5, 0.5 to 2.5, 0.5 to 1.5, 0.5 to 0.75, 0.75 to 3.5, 0.75 to 3.0, 0.75 to 2.5, 0.75 to 1.5, 1.5 to 3.5, 1.5 to 2.5, or 2.5 to 3.5. Specifically, when the chain organopolysiloxane (A') that does not contain a carbon-carbon double bond-containing reactive group in the molecule is optional, the mass ratio of component (B) to component (A) is within the range of 0.9 to 1.8, 0.9 to 1.6, 0.9 to 1.4, 0.9 to 1.2, 1.2 to 1.8, 1.2 to 1.6, 1.2 to 1.4, 1.4 to 1.8, 1.4 to 1.6, or 1.6 to 1.8. On the other hand, when this composition contains component (A') and the mass ratio of component (A) to component (A') is within the range of 95:5 to 60:40, 90:10 to 60:40, 80:20 to 60:40, 70:30 to 60:40, 90:10 to 70:30, or 80:20 to 70:30, the mass ratio of component (B) to component (A) is within the range of 0.9 to 2.4, 0.9 to 2.0, 0.9 to 1.6, or 0.9 to 1.2. In other words, as long as components (A) and (A') are used in the above mass ratio, the technical effects of the present invention can be achieved even if the mass ratio of component (B) to component (A) is within the range of more than 1.8 but less than 2.4.

[0041] When component (A') is not an essential component in the composition of the present invention, the mass ratio of component (B) to the total of components (A) and (A') is within the range of 0.9 to 1.8, and may also be within the range of 1.0 to 1.77, 1.2 to 1.6, or 1.4 to 1.5 to achieve the desired adhesive strength and storage modulus. Note that in the case of the mass ratio of component (B) to component (A), the additional use of component (A') is one of the preferred embodiments of the present invention, without impairing the technical effect of the present invention.

[0042] In contrast, when component (A') is an essential component in the composition of the present invention and the mass ratio of component (A) to component (A') is within the range of 95:5 to 40:60, the mass ratio of component (B) to the sum of components (A) and (A') is within the range of 0.9 to 2.4, 0.9 to 2.0, 0.9 to 1.6, or 0.9 to 1.2, and may also be within the range of 0.9 to 2.3 or within the range of 1.0 to 2.3.

[0043] In the present invention, component (C) is an organohydrogenpolysiloxane having two or more Si-H bonds per molecule, and serves as a crosslinking agent in the organopolysiloxane composition of the present invention. The molecular structure of component (C) is not particularly limited, and examples include linear, partially branched linear, branched, cyclic, and organopolysiloxane resin structures, with linear, partially branched linear, and organopolysiloxane resin structures being preferred. The bonding positions of the silicon-bonded hydrogen atoms are not particularly limited, and examples include molecular terminals, side chains, or both molecular terminals and side chains. The content of silicon-bonded hydrogen atoms is 0.1 to 2.0 mass%, preferably 0.5 to 1.7 mass%, and more preferably 0.8 to 1.5 mass%.

[0044] Exemplary silicon-bonded organic groups in component (C) include alkyl groups having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, and octyl; aryl groups, such as phenyl and tolyl; aralkyl groups, such as benzyl and phenethyl; and halogenated alkyl groups, such as 3-chloropropyl and 3,3,3-trifluoropropyl. Preferably, at least 50 mol% of the total group are alkyl groups having 1 to 8 carbon atoms or phenyl groups. From the standpoints of ease of production and compatibility with the above-mentioned preferred components (A) and (B), the other organic groups are preferably methyl or phenyl groups.

[0045] When component (C) of the present invention is an organopolysiloxane resin, such as an organohydrogenpolysiloxane, examples of which include organopolysiloxanes having the general formula: R'SiO 1 / 2 Siloxane units represented by the general formula: R'HSiO 1 / 2 and siloxane units represented by the formula: SiO 4 / 2Organopolysiloxane copolymers comprising siloxane units represented by the general formula: R'HSiO 1 / 2 and siloxane units represented by the formula: SiO 4 / 2 Organopolysiloxane copolymers consisting of siloxane units represented by the general formula: R'HSiO 1 / 2 and siloxane units represented by the formula: R'SiO 3 / 2 Organopolysiloxane copolymers comprising siloxane units represented by the general formula: R'HSiO 2 / 2 Siloxane units represented by the general formula: R'SiO 3 / 2 Siloxane units represented by the general formula: HSiO 3 / 2 and mixtures of two or more of these organopolysiloxanes. In the formula, R' is an alkyl group, aryl group, aralkyl group or halogenated alkyl group having 1 to 8 carbon atoms, and examples thereof are the same as those mentioned above.

[0046] Examples of component (C) include tris(dimethylhydrogensiloxy)methylsilane, tetra(dimethylhydrogensiloxy)silane, methylhydrogenpolysiloxane terminated at both ends with trimethylsiloxy groups, dimethylsiloxane / methylhydrogensiloxane copolymer terminated at both ends with trimethylsiloxy groups, dimethylpolysiloxane / methylhydrogensiloxane copolymer terminated at both ends with dimethylhydrogensiloxy groups, cyclic methylhydrogenoligosiloxane, cyclic methylhydrogensiloxane / dimethylsiloxane copolymer, methylhydrogensiloxane / diphenylsiloxane copolymer terminated at both ends with trimethylsiloxy groups, methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymer terminated at both ends with trimethylsiloxy groups, hydrolysis condensate of trimethylsilane, (CH3)2HSiO 1 / 2 Units and SiO 4 / 2 Copolymer consisting of units, (CH3)2HSiO 1 / 2 Units, SiO 4 / 2 Units, and (C6H5)SiO 3 / 2Copolymer consisting of units, (CH3)2HSiO 1 / 2 Units and CH3SiO 3 / 2 Copolymers of units, as well as mixtures of two or more of these.

[0047] In the case of a linear structure, the molecular structure: T Me2SiO(Me2SiO) q (HMeSiO) r SiMe2R T Methylhydrogenpolysiloxanes represented by the following formula are preferred. (wherein Me is a methyl group, R T is a methyl group or a hydrogen atom, and q and r are numbers that satisfy the conditions 0.3≦r / (q+r)≦1 and 5≦(q+r)≦200.) Two or more types of component (C) may be used in combination.

[0048] Similarly, the following organosiloxanes can be given as examples: In the formula, Me and Ph represent a methyl group and a phenyl group, respectively, m is an integer from 1 to 100, n is an integer from 1 to 50, b, c, d, and e are each positive numbers, and the sum of b, c, d, and e in one molecule is 1. HMe2SiO(Ph2SiO) m SiMe2H HMePhSiO(PhSiO) m SiMePhH HMePhSiO(PhSiO) m (MePhSiO) n SiMePhH HMePhSiO(PhSiO) m (Me2SiO) n SiMePhH (HMe2SiO 1 / 2 ) b (PhSiO 3 / 2 ) c (HMePhSiO 1 / 2 ) b (PhSiO 3 / 2 ) c (HMePhSiO 1 / 2 ) b(HMe2SiO 1 / 2 ) c (PhSiO 3 / 2 ) d (HMe2SiO 1 / 2 ) b (Ph2SiO 2 / 2 ) c (PhSiO 3 / 2 ) d (HMePhSiO 1 / 2 ) b (Ph2SiO 2 / 2 ) c (PhSiO 3 / 2 ) d (HMePhSiO 1 / 2 ) b (HMe2SiO 1 / 2 ) c (Ph2SiO 2 / 2 ) d (PhSiO 3 / 2 ) e .

[0049] [SiH / Vi ratio] The composition of the present invention is hydrosilylation-curable, and the amount of component (C) used is not particularly limited as long as the composition can be sufficiently cured by the hydrosilylation reaction. However, the molar ratio (i.e., the amount of silicon-bonded hydrogen (SiH) groups in component (C) relative to the sum of the amount (substance amount) of alkenyl groups in component (A) and the amount (substance amount) of alkenyl groups in component (B) in the composition is preferably within the range of 1.0 to 100, and may also be within the range of 5.0 to 60, 10 to 50, or 20 to 50.

[0050] On the other hand, to improve adhesion to substrates such as glass, the number of SiH groups per molecule can be 3 to 5 or more, preferably more than 10, and more preferably 20 or more. For example, the ratio of the amount of silicon-bonded hydrogen (SiH) groups in component (C) to the sum of the amount (amount) of alkenyl groups in component (A) and the amount (amount) of alkenyl groups in component (B) in the composition can be designed to be in the range of 10 to 60 or 10 to 50. If the amount of SiH groups is below the above-mentioned lower limit, the technical effect of improving adhesion to the substrate may not be achieved. On the other hand, if the amount of SiH groups exceeds the above-mentioned upper limit, the amount of unreacted curing agent remaining increases, which may adversely affect cured physical properties such as brittleness of the cured product or cause problems such as gas generation. However, even if the SiH / Vi ratio of the composition is outside the above-mentioned range, a pressure-sensitive adhesive layer sufficient for practical use can be formed.

[0051] [Hydrosilylation reaction catalyst] Component (D) The organopolysiloxane composition of the present invention contains a hydrosilylation catalyst. Examples of hydrosilylation catalysts include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts. Platinum-based catalysts are preferred because they significantly accelerate the curing of the composition. Examples of platinum-based catalysts include platinum fine powder, chloroplatinic acid, alcohol solutions of chloroplatinic acid, platinum-alkenylsiloxane complexes, platinum-olefin complexes, and platinum-carbonyl complexes. Platinum-alkenylsiloxane complexes are particularly preferred. Examples of alkenylsiloxanes include 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, alkenylsiloxanes in which some of the methyl groups of these alkenylsiloxanes have been substituted with groups selected from the group consisting of nitrile, amide, dioxolane, sulfolane, ethyl, and phenyl, and alkenylsiloxanes in which the vinyl groups of these alkenylsiloxanes have been substituted with allyl, hexenyl, or the like. 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is particularly preferred because of the good stability of the platinum-alkenylsiloxane complex. Non-platinum metal catalysts such as iron, ruthenium, and iron / cobalt can be used as catalysts to promote the hydrosilylation reaction.

[0052] In the present invention, the content of the hydrosilylation catalyst is not particularly limited, but the amount of platinum-based metal relative to the total solid content of the composition is within the range of 0.1 to 200 ppm, or may be within the range of 0.1 to 150 ppm, 0.1 to 100 ppm, or 0.1 to 60 ppm. Here, platinum-based metals refer to Group VIII metal elements consisting of platinum, rhodium, palladium, ruthenium, and iridium. However, for practical purposes, it is preferable that the content of platinum metal excluding the ligands of the hydrosilylation catalyst be within the above range. The solid content refers to the components that form a cured layer when the organopolysiloxane composition of the present invention is cured (mainly the base resin, adhesion-imparting component, crosslinking agent, catalyst, and other non-volatile components), but does not include volatile components such as solvents that volatilize during heat curing.

[0053] When the platinum-based metal content in the organopolysiloxane composition of the present invention is 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 25 ppm or less, or 20 ppm or less, discoloration or coloring of the transparent pressure-sensitive adhesive layer can be suppressed, particularly after curing, when heated, or when exposed to high-energy rays such as ultraviolet rays. On the other hand, from the viewpoint of the curability of the organopolysiloxane composition, the platinum-based metal content should be 0.1 ppm or more; if it is less than this lower limit, it may cause poor curing.

[0054] In the present invention, component (E) is a cure retarder (=cure inhibitor) that is incorporated to inhibit the crosslinking reaction between the alkenyl groups in the composition and the SiH groups in component (C), thereby extending the usable life at room temperature and improving storage stability. Therefore, in practice, component (E) may be added to the pressure-sensitive adhesive layer-forming organopolysiloxane composition of the present invention.

[0055] Specific examples of component (E) include acetylene compounds, ene-yne ​​compounds, organic nitrogen compounds, organic phosphorus compounds, and oxime compounds.Specific examples include alkyne alcohols such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 1-ethynyl-1-cyclohexanol, and phenylbutanol; ene-yne ​​compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-1-hexen-3-yne; methylalkenylcyclosiloxanes such as 2-ethynyl-4-methyl-2-pentene, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane; and benzotriazole.

[0056] From the viewpoint of the curing behavior of the composition, the pressure-sensitive adhesive layer-forming organopolysiloxane composition of the present invention is curable at 80 to 200°C, and preferably exhibits a viscosity increase of no more than 1.5 times after 8 hours at room temperature following the composition's preparation. Suppressing viscosity increase is important from the viewpoints of ease of handling, pot life, and post-curing properties. Even if a large amount of excess component (C) is contained and the platinum-based metal content is optionally low, curability can be ensured by curing at a high temperature of at least a certain temperature (80 to 200°C). Such a composition can be achieved by selecting an appropriate combination and amounts of the above-mentioned components, hydrosilylation catalyst, and component (E).

[0057] In addition to the preferred components (A) and (B), the organopolysiloxane composition of the present invention may contain an organic solvent as a solvent. The type and amount of organic solvent can be adjusted taking into account factors such as coating workability. Exemplary organic solvents include aromatic hydrocarbon solvents such as toluene, xylene, and benzene; aliphatic hydrocarbon solvents such as heptane, hexane, octane, and isoparaffin; ester solvents such as ethyl acetate and isobutyl acetate; ether solvents such as diisopropyl ether and 1,4-dioxane; chlorinated aliphatic hydrocarbon solvents such as trichloroethylene, perchloroethylene, and methylene chloride; and volatile oil solvents. Two or more types can be combined depending on the wettability of the sheet-like substrate. The amount of organic solvent is preferably an amount that allows the mixture of components (A) to (C) to be uniformly applied to the surface of the sheet-like substrate. For example, the amount may be 5 to 3,000 parts by mass per 100 parts by mass of the total amount of components (A), (B), and (C).

[0058] The organopolysiloxane composition of the present invention may optionally contain components other than those described above, provided that the effects of the present invention are not impaired. For example, the composition may contain an adhesion promoter; a non-reactive organopolysiloxane such as polydimethylsiloxane or polydimethyldiphenylsiloxane; an antioxidant such as a phenol-type, quinone-type, amine-type, phosphorus-type, phosphite-type, sulfur-type, or thioether-type antioxidant; a flame retardant such as a phosphate ester-type, halogen-type, phosphorus-type, or antimony-type; and one or more antistatic agents such as cationic surfactants, anionic surfactants, or nonionic surfactants. In addition to these components, pigments, dyes, inorganic fine particles (e.g., reinforcing fillers, dielectric fillers, conductive fillers, or thermally conductive fillers), etc., may also be optionally mixed.

[0059] [(A') Linear / chain organopolysiloxane that does not contain a carbon-carbon double bond-containing reactive group in the molecule] The organopolysiloxane composition of the present invention can contain a non-reactive organopolysiloxane, such as polydimethylsiloxane or polydimethyldiphenylsiloxane, that does not contain a carbon-carbon double bond-containing reactive group, such as an alkenyl group, an acrylic group, or a methacrylic group. As a result, the loss factor (tan δ), storage modulus (G'), loss modulus (G"), and adhesive properties of the pressure-sensitive adhesive layer can be improved. For example, the loss factor of the pressure-sensitive adhesive layer can be increased by using a hydroxyl-terminated polydimethylsiloxane, or a trimethylsiloxy-terminated polydimethylsiloxane or polydimethyldiphenylsiloxane, and such compositions are within the scope of the present invention.

[0060] Specifically, when the mass ratio of component (B) to the sum of components (A) and (A') is within the range of 0.9 to 2.4, the mass ratio of component (A) to component (A') must be within the range of 95:5 to 40:60, and it is preferable that the mass ratio of component (A) to component (A') is within the range of 90:10 to 40:60.

[0061] Optional Tetraalkoxysilane or Tetraalkoxysilane Prepolymer as a Fixing Additive In order to increase or improve adhesion, the present invention can incorporate tetraalkoxysilane or tetraalkoxysilane prepolymer as a fixing additive in at least one silicone-based PSA composition.The rheological / viscoelastic properties of a cured silicone PSA layer are generally determined by its crosslinked polymer structure (including polymer chain length), resin structure (including silicone resin unit and Mw), and the molar ratio therein, resulting in a trade-off between low Tg or elastic modulus and high adhesion.However, by using tetraalkoxysilane or tetraalkoxysilane prepolymer as a fixing additive, it can increase only adhesion without affecting the low Tg or elastic modulus properties of the cured silicone PSA layer.

[0062] In a preferred embodiment of the present invention, the adhesive strength of a 50 μm thick pressure-sensitive adhesive layer obtained by curing the composition is greater than 20%, preferably 30% to 80%, than the adhesive strength of a pressure-sensitive adhesive layer obtained from the same composition but not containing tetraalkoxysilane as a fixing additive, when measured on a glass substrate or the like using a 180° peel test method in accordance with JIS Z 0237 at a tensile speed of 300 mm / min.

[0063] To achieve this technical benefit, the tetraalkoxysilane is exemplified by tetramethoxysilane, tetraethoxysilane, or a mixture thereof. Substituting other silanes, such as glycidoxypropyltrimethoxysilane or vinyltrimethoxysilane, for the tetraalkoxysilane does not improve or enhance adhesive strength without affecting the rheological / viscoelastic properties of the silicone-based pressure-sensitive adhesive layer. Furthermore, to sufficiently improve adhesive strength, the amount of tetraalkoxysilane relative to the total mass of components (A) to (C) is in the range of 0.1 to 9.0 mass%, preferably 0.2 to 7.0 mass%, and more preferably 0.5 to 5.0 mass%, assuming a mass ratio of component (B) to component (A) of 0.5 to 3.5. If the tetraalkoxysilane content is below the lower limit, the technical effect of improving adhesion to the substrate may not be fully achieved. In contrast, if the amount of tetraalkoxysilane exceeds the upper limit, an excess of tetraalkoxysilane or tetraalkoxysilane prepolymer may adversely affect cured properties.

[0064] The silicone-based PSA-forming composition can be prepared by any method, including uniformly mixing the components together, adding a solvent if necessary, and mixing at a temperature of 0 to 200°C using a known mixer or kneader.

[0065] [Formation of adhesive layer using the silicone-based PSA-forming composition] The silicone-based PSA-forming composition forms a cured adhesive layer when applied to a substrate, and forms a cured product by heating at a temperature of 80 to 200° C., preferably 90 to 190° C. Coating methods include, for example, gravure coating, offset coating, offset gravure, roll coating, reverse roll coating, air knife coating, curtain coating, and comma coating.

[0066] Cured adhesive layers from the silicone-based PSA-forming compositions are disposed between functional layers to bond / assemble the layers in the electronic articles of the present invention.

[0067] [Transparency, color tone, or coloring and discoloration properties of the pressure-sensitive adhesive layer] The interlayer adhesive layer used in the present invention is preferably the aforementioned silicone-based PSA layer and can be a transparent or opaque assembly layer. That is, transparency is an optional property of the interlayer adhesive layer of the present invention and depends on where the interlayer adhesive layer is located within the electronic device. If the interlayer adhesive layer is placed on top of a panel unit adjacent to its cover glass or other transparent cover unit, it should be a "transparent" interlayer adhesive layer. On the other hand, if the interlayer adhesive layer is located at the bottom of a panel unit, transparency is not required. Nevertheless, the interlayer adhesive layer of the present invention may be substantially transparent, translucent, or opaque, and its transparency can be designed according to the intended use of the interlayer adhesive layer. For example, for the interlayer pressure-sensitive adhesive layer used in the display device of the present invention, the film-like cured product having a thickness of 1 to 1,000 μm obtained by curing the silicone-based PSA-forming composition is preferably visually transparent and preferably does not contain coloring additives such as carbon black. Furthermore, when the pressure-sensitive adhesive layer for display devices formed from a 100 μm-thick cured layer is visually transparent, the transmittance of light with a wavelength of 450 nm is 80% or more, preferably 90% or more, and may be designed to be 95% or more, more objectively, when the value for air is taken as 100%. On the other hand, for bonding electrical or electronic components that do not require light transmittance, a translucent to opaque pressure-sensitive adhesive layer may be used, and filler components or additives that impair colorability or light transmittance may be used depending on required characteristics other than light transmittance.

[0068] In addition to the transparency, the interlayer adhesive layer can be designed to prevent coloration of the cured product by optionally reducing the content of platinum-based metals in the cured layer. Specifically, the L defined in JIS Z 8729 immediately after curing of a 100 μm-thick cured layer obtained by curing the organopolysiloxane composition of the present invention is * a * b * b measured in the color system * The value of b can be set to 0.15 or less to 0.10 or less. * Having a value of 0.1 means that the cured layer is substantially transparent and not yellow in color.

[0069] The cured layer of the present invention can be designed so that its color tone does not change significantly, and in particular, does not cause the problem of yellowing, even when exposed to high temperatures or high-energy rays such as ultraviolet rays for a long period of time. Specifically, in any of the following evaluations, a 100 μm-thick cured layer obtained by curing the organopolysiloxane composition of the present invention has a color tone that does not change significantly, and does not cause the problem of yellowing. * a * b * b measured in the color system * The change in value (Δb * ) can be designed to be 0.20 or less, preferably 0.15 or less. * is the absolute value of the change in value. (1) Heat aging evaluation: The cured layer was aged at 105°C for 300 hours. (2) High-energy ray irradiation: The hardened layer sample is irradiated with high-energy ray with an intensity of 12 mW / cm at 365 nm. 2 and the intensity at 254 nm is 3.5 mW / cm 2 The sample is irradiated with ultraviolet light at room temperature for 75 hours using a mercury lamp (for example, Optical Module X manufactured by Ushio Electric Co., Ltd.).

[0070] Use as an interlayer pressure-sensitive adhesive layer applied to electronic articles To improve adhesion to the adherend, the surface of the adhesive layer or substrate may be subjected to surface treatment such as primer treatment, corona treatment, etching treatment, plasma treatment, etc. However, because the adhesive layer obtained by curing the silicone-based PSA-forming composition has excellent adhesion to substrates such as display devices, as described above, these steps can be added as necessary to further improve adhesion to the adherend, and omitting these steps can achieve higher production efficiency.

[0071] The silicone-based PSA-forming composition can be applied to a release liner, heated under the temperature conditions described above, and then peeled off the release liner and applied to a film-like, tape-like, or sheet-like substrate (hereinafter referred to as a "film-like substrate"), or applied to a film-like substrate, followed by heat curing under the temperature conditions described above to form a pressure-sensitive adhesive layer on the substrate surface. The cured layer obtained by curing the silicone-based PSA-forming composition on these film-like substrates, particularly a laminate having a film-like pressure-sensitive adhesive layer, is used to bond or assemble functional layers in the construction of electronic articles and the use of laminated touchscreens or flat panel displays. As described above, the adhesive layer is applied as a single coating layer having both the assembly / bonding layer function and the damping / shock-absorbing layer function, and the manufacturing process for the electronic article of the present invention can be a simplified process that does not require a multi-step lamination / coating process to construct the interlayer damping or shock-absorbing layer.

[0072] The coating amount of the silicone-based PSA-forming composition can be designed to a desired thickness depending on the application, such as a display device, and the thickness of the pressure-sensitive adhesive layer after curing may be, but is not limited to, 1 to 1000 μm, 5 to 900 μm, or 10 to 800 μm, for example.

[0073] The pressure-sensitive adhesive layer according to the present invention may be a single layer or a multilayer structure in which two or more pressure-sensitive adhesive layers are laminated, depending on the required properties. Multiple pressure-sensitive adhesive layers may be formed by bonding pressure-sensitive adhesive films (formed for each film), or the step of applying a silicone-based PSA-forming composition onto a film substrate (including a release layer) or the like and curing it may be carried out multiple times.

[0074] In addition to the function of bonding or adhering between components and the function of a damping / shock absorbing layer, the pressure-sensitive adhesive layer may also serve as another functional layer selected from a dielectric layer, a conductive layer, a heat dissipation layer, an insulating layer, a reinforcing layer, etc.

[0075] When the adhesive layer obtained by curing the silicone-based PSA-forming composition is a pressure-sensitive adhesive layer, particularly a pressure-sensitive adhesive layer, the cured layer is preferably treated as a laminate film releasably adhered to a film substrate equipped with a release layer having release coating capability. The release layer is also called a release liner, separator, release layer, or release coating layer, and is preferably a release layer having release coating capability using a silicone-based release agent, a fluorine-based release agent, an alkyd-based release agent, or a fluorosilicone-based release agent. By physically forming fine irregularities on the surface of the substrate, the substrate itself may be formed to be less adhesive to the resin sheet for a pressure-sensitive adhesive layer of the present invention. In particular, in the laminate of the present invention, a release layer obtained by curing a fluorosilicone-based release agent is preferably used as the release layer.

[0076] The interlayer adhesive layer, which is preferably a silicone-based PSA layer, has the viscoelastic properties and adhesive strength in the tan δ curve measurement described above, making it useful as an elastic adhesive member for various electronic devices and electrical devices. In particular, the interlayer adhesive layer is useful as an electronic material, a display device member, or a transducer (including a sensor, speaker, actuator, or generator) member, and the cured product is preferably used as a member for electronic components or a display device. The cured product according to the present invention may be transparent or opaque. However, a film-like cured product, particularly a substantially transparent pressure-sensitive adhesive film, is particularly suitable as a display panel or display member, and is particularly useful for so-called touch panel applications, where devices, particularly electronic devices, can be operated by touching the screen with a fingertip or the like. Furthermore, since an opaque elastic adhesive layer does not require transparency, it is particularly useful for film- or sheet-like members used in sensors, speakers, actuators, etc., where a certain degree of elasticity and flexibility is required for the adhesive layer itself.

[0077] Furthermore, the interlayer adhesive layer of the present invention can achieve pressure-sensitive adhesive properties equivalent to those of conventional silicone pressure-sensitive adhesive layers, can improve adhesion to substrates such as display devices, and can also provide impact resistance to electronic articles as a damping / impact absorbing layer in the electronic articles of the present invention. [Example]

[0078] These examples are intended to illustrate the present invention to one of ordinary skill in the art and should not be construed as limiting the scope of the invention as defined in the claims. The materials listed in Table 1 were used in these examples. The viscosity and plasticity of each component in the present invention were measured at room temperature using the following methods.

[0079] (viscosity) Viscosity (mPa.s) is a value measured using a rotational viscometer conforming to JIS K7117-1, and kinematic viscosity (mm 2 / s) is a value measured using an Ubbelohde viscometer in accordance with JIS Z8803.

[0080] (Plasticity) The plasticity was expressed as a value measured in accordance with the method specified in JIS K 6249 (the thickness when a 1 kgf load was applied to a 4.2 g spherical sample at 25°C for 3 minutes was read to the nearest 1 / 100 mm, and this value was multiplied by 100).

[0081] [Table 1]

[0082] [Preparation of Curable Organopolysiloxane Composition] The curable organopolysiloxane compositions described in each of the Examples and Comparative Examples were prepared using the components shown in Table 1. The formulations of the Examples and Comparative Examples are also summarized in Table 2.

[0083] [Measurement of molecular weight of organopolysiloxane component] The weight average molecular weight (Mw) and number average molecular weight (Mn) of organopolysiloxane components such as organopolysiloxane resins were determined in terms of standard polystyrene using a Waters gel permeation chromatography (GPC) with tetrahydrofuran (THF) as the solvent.

[0084] [Viscoelasticity: Dynamic Mechanical Analysis: tanδ] Each composition was applied to a release liner coated with a fluorosilicone release coating to a cured thickness of approximately 120 μm, followed by curing at 70°C for 10 minutes and then at 150°C for 10 minutes. Five or more pressure-sensitive adhesive films were laminated together to obtain film samples with thicknesses ranging from 500 μm to 1200 μm, sandwiched between release liners on both sides. The films were cut into 8 mm diameter circles and subjected to dynamic mechanical analysis using a parallel plate measurement system on a TA Model DHR-2 rheometer equipped with a mechanical chiller system. Measurement conditions were a frequency of 1 Hz, a heating rate of 3°C / min, and a temperature range of -70°C to 200°C. The storage modulus (G'), loss modulus (G"), and tangent point (tanδ) were determined, and the temperature at which tanδ peaked (Tg), the tangent point (tanδ) value at the peak, and the temperature range over which tanδ exceeded 0.5 were recorded.

[0085] Example 1 21.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 3.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 53.5 parts by weight of MQ silicone resin B-3, 47.0 parts by weight of toluene, 0.44 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-capped with trimethylsiloxy groups, 0.05 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.12 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 0.97 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio (SiH / Vi ratio) of the SiH groups in components C-1 and C-2 to the amount of alkenyl groups in components A-1 and A-2 was 36.2, and the platinum metal content relative to the solid content was 80.0 ppm.

[0086] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0087] Example 2 21.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 53.5 parts by weight of MQ silicone resin B-3, 40.0 parts by weight of toluene, 0.44 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-capped with trimethylsiloxy groups, and 0.10 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 0.92 parts by weight of platinum-based hydrosilylation reaction catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-1 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 33.1, and the platinum metal content relative to the solids content was 80.1 ppm.

[0088] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0089] Example 3 21.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 71.5 parts by weight of MQ silicone resin B-3, 45.4 parts by weight of toluene, 0.44 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-capped with trimethylsiloxy groups, and 0.10 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 1.12 parts by weight of platinum-based hydrosilylation reaction catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-1 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 33.1, and the platinum metal content relative to the solids content was 79.9 ppm.

[0090] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0091] Example 4 25.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 45.7 parts by weight of MQ silicone resin B-2, 2.4 parts by weight of MQ silicone resin B-3, 49.1 parts by weight of toluene, 0.28 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, 0.01 parts by weight of cure inhibitor E-1, and 0.21 parts by weight of cure inhibitor E-2 were thoroughly mixed at room temperature, and then 0.91 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in component A-2 (SiH / Vi ratio) was 40.2, and the platinum metal content relative to the solids content was 81.7 ppm.

[0092] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0093] Example 5 27.4 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 45.7 parts by weight of MQ silicone resin B-2, 2.4 parts by weight of MQ silicone resin B-3, 54.7 parts by weight of toluene, 0.33 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, 0.02 parts by weight of cure inhibitor E-1, and 0.21 parts by weight of cure inhibitor E-2 were thoroughly mixed at room temperature, and then 0.95 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in component A-2 (SiH / Vi ratio) was 43.3, and the platinum metal content relative to the solids content was 81.5 ppm.

[0094] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0095] Example 6 A curable organopolysiloxane composition was formed by thoroughly mixing 16.3 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 7.0 parts by weight of non-functional (trimethylsilyl-blocked) polydimethylsiloxane gum A', 45.0 parts by weight of MQ silicone resin B-3, 36.8 parts by weight of toluene, 0.40 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-blocked with trimethylsiloxy groups, and 0.20 parts by weight of cure inhibitor E-1 at room temperature. Then, 0.36 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-1 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 38.7, and the platinum metal content relative to the solids content was 33.6 ppm.

[0096] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0097] Example 7 A curable organopolysiloxane composition was formed by thoroughly mixing 14.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 9.3 parts by weight of non-functional (trimethylsilyl-blocked) polydimethylsiloxane gum A', 45.0 parts by weight of MQ silicone resin B-3, 36.8 parts by weight of toluene, 0.40 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-blocked with trimethylsiloxy groups, and 0.20 parts by weight of cure inhibitor E-1 at room temperature. Then, 0.36 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-1 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 45.2, and the platinum metal content relative to the solids content was 33.6 ppm.

[0098] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0099] [For example, results of a ball drop test on a laminate using the interlayer adhesive layer obtained in Example 7] A 120 μm thick pressure-sensitive adhesive film measuring 149 mm x 69.5 mm was laminated between a 449 mm x 430 mm x 20 mm stainless steel sheet and a 149 mm x 69.5 mm x 0.342 mm glass sheet using a plastic hand roller. The laminate was placed horizontally with the stainless steel plate underneath and the glass plate facing up, and a 5.6 g stainless steel ball with a diameter of 11.11 mm was dropped onto the glass surface from a height of 300 mm. The impact resistance of the pressure-sensitive adhesive film on the laminate was observed by determining whether the glass sheet broke. The results are shown in Figure 1.

[0100] Example 8 11.7 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 11.7 parts by weight of non-functional (trimethylsilyl-blocked) polydimethylsiloxane gum A', 45.0 parts by weight of MQ silicone resin B-3, 36.8 parts by weight of toluene, 0.40 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-blocked with trimethylsiloxy groups, and 0.20 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 0.36 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-1 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 54.2, and the platinum metal content relative to the solids content was 33.6 ppm.

[0101] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0102] Comparative Example 1 23.3 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 56.8 parts by weight of MQ silicone resin B-1, 2.9 parts by weight of MQ silicone resin B-3, 30.0 parts by weight of toluene, 0.25 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.15 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 1.08 parts by weight of platinum-based hydrosilylation reaction catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 35.6, and the platinum metal content relative to the solids content was 78.7 ppm.

[0103] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0104] [For example, results of a ball drop test on a laminate using the interlayer adhesive layer obtained in Comparative Example 1] A 120 μm thick pressure-sensitive adhesive film measuring 149 mm x 69.5 mm was laminated between a 449 mm x 430 mm x 20 mm stainless steel sheet and a 149 mm x 69.5 mm x 0.342 mm glass sheet using a plastic hand roller. The laminate was placed horizontally with the stainless steel plate underneath and the glass plate facing up, and a 5.6 g stainless steel ball with a diameter of 11.11 mm was dropped onto the glass surface from a height of 300 mm. The impact resistance of the pressure-sensitive adhesive film on the laminate was observed by determining whether the glass sheet broke. The results are shown in Figure 2.

[0105] Comparative Example 2 23.3 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 6.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 56.8 parts by weight of MQ silicone resin B-1, 2.9 parts by weight of MQ silicone resin B-3, 44.0 parts by weight of toluene, 0.32 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.18 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 1.17 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in components A-1 and A-2 (SiH / Vi ratio) was 36.8, and the platinum metal content relative to the solids content was 78.6 ppm.

[0106] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0107] Comparative Example 3 23.3 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 13.5 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 56.8 parts by weight of MQ silicone resin B-1, 2.9 parts by weight of MQ silicone resin B-3, 61.4 parts by weight of toluene, 0.42 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.22 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 1.28 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in components A-1 and A-2 (SiH / Vi ratio) was 39.0, and the platinum metal content relative to the solids content was 78.5 ppm.

[0108] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0109] Comparative Example 4 23.3 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 19.5 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 56.8 parts by weight of MQ silicone resin B-1, 2.9 parts by weight of MQ silicone resin B-3, 75.4 parts by weight of toluene, 0.44 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.25 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 1.38 parts by weight of platinum-based hydrosilylation catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in components A-1 and A-2 (SiH / Vi ratio) was 35.4, and the platinum metal content relative to the solids content was 78.5 ppm.

[0110] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0111] Comparative Example 5 21.0 parts by weight of vinyl-functional polydimethylsiloxane gum A-1, 91.5 parts by weight of MQ silicone resin B-3, 51.4 parts by weight of toluene, 0.44 parts by weight of dimethylsiloxane / methylhydrogensiloxane copolymer C-1 end-capped with trimethylsiloxy groups, and 0.10 parts by weight of cure inhibitor E-1 were thoroughly mixed at room temperature, and then 1.33 parts by weight of platinum-based hydrosilylation reaction catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-1 to the amount of alkenyl groups in component A-1 (SiH / Vi ratio) was 33.1, and the platinum metal content relative to the solids content was 79.7 ppm.

[0112] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0113] Comparative Example 6 22.6 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 70.7 parts by weight of MQ silicone resin B-2, 2.4 parts by weight of MQ silicone resin B-3, 52.0 parts by weight of toluene, 0.23 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.21 parts by weight of cure inhibitor E-2 were thoroughly mixed at room temperature, and then 1.13 parts by weight of platinum-based hydrosilylation reaction catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in component A-2 (SiH / Vi ratio) was 36.5, and the platinum metal content relative to the solids content was 81.2 ppm.

[0114] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0115] Comparative Example 7 22.6 parts by weight of vinyl-functional polydimethylsiloxane gum A-2, 55.7 parts by weight of MQ silicone resin B-2, 2.4 parts by weight of MQ silicone resin B-3, 46.9 parts by weight of toluene, 0.23 parts by weight of methylhydrogensiloxane polymer C-2 end-capped with trimethylsiloxy groups, and 0.21 parts by weight of cure inhibitor E-2 were thoroughly mixed at room temperature, and then 0.98 parts by weight of platinum-based hydrosilylation reaction catalyst D was added to the mixture and thoroughly mixed to form a curable organopolysiloxane composition. The molar ratio of SiH groups in component C-2 to the amount of alkenyl groups in component A-2 (SiH / Vi ratio) was 36.5, and the platinum metal content relative to the solids content was 81.6 ppm.

[0116] After this composition was cured by the above method, the viscoelasticity was measured by the above method. The evaluation results are shown in Table 3.

[0117] [Table 2]

[0118] [Table 3]

[0119] As shown in Table 3, the silicone-based PSA layer-forming compositions of Examples 1 to 8 provided interlayer adhesive layers having a tan δ peak temperature of less than 35°C and a tan δ peak value of greater than 1.0. Electronic articles using interlayer adhesive layers obtained with the compositions of Examples 1 to 8 in their construction were expected to be sufficiently bonded / assembled between functional layers so as to achieve better damping / shock absorption properties in the interlayer adhesive layer. That is, as shown in Figure 1 of the ball drop test on the laminate using Example 7, no cracks or damage were observed in the laminate having the interlayer adhesive layer according to the present invention.

[0120] In contrast, Comparative Examples 1 to 8 did not provide interlayer adhesive layers that satisfied the required properties of the present invention. Electronic articles constructed using interlayer adhesive layers obtained from the compositions of Comparative Examples 1 to 7 were expected to have insufficient damping / impact absorption in the interlayer adhesive layers. As shown in Figure 2 of a ball drop test on a laminate using Comparative Example 1, the ball drop resulted in large and significant cracks being observed in the laminate.

Claims

1. An electronic article having an interlayer adhesive layer having a tan δ peak temperature of less than 35°C and a tan δ value at the peak of greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system.

2. 2. The electronic article of claim 1, wherein the width of the tan δ peak of the interlayer adhesive layer is less than 90° C. when the tan δ value is defined by the absolute value of the temperature range over which it is greater than 0.

5.

3. The tan δ curve of the interlayer adhesive layer, when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system, satisfies the following condition: i) the temperature at the tan δ peak is located between −50° C. and 25° C.; and ii) The electronic article of claim 1, wherein the width of the tan δ peak, defined by the absolute value of the temperature range over which the tan δ value exceeds 0.5, is in the range of 50°C to less than 90°C.

4. The interlayer adhesive layer comprises components (A) to (D), (A) a linear organopolysiloxane having an average of more than one alkenyl group per molecule; (B) an organopolysiloxane resin in which the total content of hydroxyl groups and hydrolyzable groups relative to all silicon atoms in the molecule is 9 mol % or less; (C) an organohydrogenpolysiloxane having at least two Si—H bonds in one molecule, and (D) a hydrosilylation reaction catalyst; 4. The electronic article according to claim 1, wherein the adhesive layer is a pressure-sensitive silicone adhesive layer obtained by curing a silicone-based pressure-sensitive adhesive-forming composition comprising:

5. At least a part of the component (A) has a viscosity of 100,000 mPa.s or more at 25°C when measured by the method described in JIS K6249, or a plasticity in the range of 50 to 200, and the alkenyl group is vinyl (CH ２ a crude rubber-like alkenyl group-containing organopolysiloxane having a content of (═CH—) moieties in the range of 0.005 to 0.400 mass %, The component (B) is (B1)R ３ SiO １／２ Units and SiO ４／２ an organopolysiloxane resin or mixture thereof consisting essentially of units, wherein R is a monovalent organic group, and 90 mol % or more of the R are alkyl groups having 1 to 6 carbon atoms or phenyl groups; component (C) is present in an amount such that the molar ratio of the amount of SiH groups in component (C) to the total amount of alkenyl groups in components (A) and (B) is 1 to 100; 5. The electronic article of claim 4, wherein component (D) is a platinum-based catalyst and is present in an amount such that the content of platinum-based metal in the solids of the composition is within the range of 0.1 to 200 ppm in the silicone-based pressure-sensitive adhesive-forming composition excluding the solvent.

6. 5. The electronic article of claim 4, wherein component (C) is present in an amount such that the molar ratio of the amount of SiH groups in component (C) to the total amount of alkenyl groups in components (A) and (B) is 10 to 60.

7. 5. The electronic article according to claim 4, wherein the silicone-based pressure-sensitive adhesive-forming composition further comprises (A') a linear organopolysiloxane that does not contain a carbon-carbon double bond-containing reactive group in the molecule.

8. The electronic article of any one of claims 1 to 3, wherein the interlayer adhesive layer provides impact resistance to the electronic article as a damping / shock absorbing layer and is disposed between two functional layers to bond or assemble the two functional layers.

9. The electronic article of any one of claims 1 to 3, wherein the interlayer adhesive layer is substantially transparent and is disposed between two functional layers, at least one of which is substantially transparent, to provide impact resistance to the electronic article as a damping / shock absorbing layer and to bond or assemble the two functional layers.

10. The electronic article according to any one of claims 1 to 3, wherein the electronic article is a display device having a structure in which a display unit is directly bonded to or assembled with another functional unit via the interlayer adhesive layer, thereby providing the electronic article with impact resistance as a damping / impact absorbing layer.

11. 4. The electronic article according to claim 1, wherein the thickness of the interlayer adhesive layer is in the range of 10 to 1000 μm, and the interlayer adhesive layer is disposed between two functional layers to bond or assemble the two functional layers as a single adhesive layer, and serves as a damping / shock absorbing layer in the electronic article to provide impact resistance to the electronic article.

12. 4. The electronic article according to claim 1, wherein the electronic article is substantially free of any additional interlayer damping / shock absorbing layer disposed between two functional layers other than the interlayer adhesive layer, the temperature at the tan δ peak being less than 35° C. and the tan δ value at the peak being greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system.

13. 13. A process for manufacturing an electronic article according to any one of claims 1 to 12, comprising assembling or bonding at least two functional layers with an interlayer adhesive layer having a tan δ peak temperature of less than 35°C and a tan δ peak value of greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system.

14. 1. Use of an interlayer adhesive layer as a damping / shock absorbing layer in an electronic article, wherein the interlayer adhesive layer has a temperature at tan δ peak of less than 35° C. and a tan δ value at the peak of greater than 1.0 when measured at 1 Hz by a dynamic mechanical analysis rheometer using a parallel plate measurement system.

15. 15. The use of claim 14, wherein there is a single interlayer adhesive layer between two functional layers in the electronic article, and no additional interlayer foam layer or damping / shock absorbing layer is present.

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