A releaseable laminate containing a multilayer silicone adhesive layer, a method of using the same, and a method of manufacturing the same.

Abstract

The present invention provides a peelable laminate, etc., that exhibits easy peelability while the adhesive layer after peeling shows sufficient adhesive strength for practical use. [Solution] A substrate having a release layer is provided with a first silicone adhesive layer and a second silicone adhesive layer laminated on the same layer, wherein the second silicone adhesive layer is of formula:R3SiO 1 / 2 Siloxane units represented by the formula: SiO (wherein R is the same or different monovalent organic group with 1 to 12 carbon atoms) 4 / 2 A releaseable laminate containing a multilayer silicone adhesive layer, characterized in that it contains a silicone resin containing siloxane units represented by , the content of which is higher than the content of silicone resin in the first silicone adhesive layer, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer; a method for using and manufacturing the same; a method for designing the same; and a use of the laminate and curing reactive silicone composition for the purpose of manufacturing the same.

Description

[Technical Field]

[0001] The present invention relates to a release laminate containing a multilayer silicone adhesive layer, a method of using the same, and a method of manufacturing the same. Similarly, the present invention relates to a method of manufacturing an electronic component or a display, which includes a method of using the release laminate in at least part of its manufacturing process; a laminate used in the manufacture of the release laminate; a method of designing the release laminate; and the use of a curing reactive silicone composition for the purpose of manufacturing the release laminate.

[0002] Silicone-based adhesives are used in a variety of applications due to their excellent tackiness and cohesiveness, as well as their superior heat resistance, electrical properties, low-temperature properties, and water resistance. Furthermore, it has been proposed to create multilayer structures by laminating a silicone-based adhesive layer with a silicone rubber layer or other elastomer layer to suppress changes in release properties over time, achieve high adhesive strength at high temperatures, and bond silicone rubber sheets to other components at low cost (Patent Documents 1-3). In addition, the applicant of this invention has proposed a method for manufacturing a silicone-based adhesive that has low modulus but low peel resistance to a release substrate, which involves forming a silicone layer (I) containing 50% by mass or more of silicone resin on one side of a release substrate, and then forming a silicone-based cured layer that does not contain silicone resin or contains less silicone resin than layer (I) (Patent Document 4).

[0003] However, laminates containing these silicone-based adhesive layers, especially when the silicone-based adhesive layer is used as an adhesive without a support, exhibit high peel resistance to the release substrate. This can lead to damage to the adhesive layer during peeling, or result in uneven peeling and noises such as zipping, making it difficult to achieve sufficient easy peelability. In particular, with the increasing regulation of organic fluorine compounds such as PFAS and fluororesins (including fluorosilicone-based release resins) in recent years, easy peelability is required even for release layers that do not contain fluorine. However, adhesive layers in laminates containing these silicone-based adhesive layers may not be able to achieve sufficient easy peelability. Furthermore, there is often a trade-off between the easy peelability of an adhesive layer relative to the release layer and its adhesive strength / bonding strength to the component. When using an easily peelable silicone-based adhesive layer for bonding or assembling electronic components or flexible displays, sufficient adhesive strength or bonding strength may not be achieved. Therefore, there is a strong industrial need for a releaseable laminate containing a silicone-based adhesive layer that exhibits sufficiently low peel resistance to the release layer (especially a fluorine-free release layer) and has sufficient adhesive strength for the manufacture of electronic components, flexible displays, etc. In particular, a releaseable laminate that provides a silicone-based adhesive without a support that is easily peelable to the release layer and has sufficient adhesive strength.

[0004] Furthermore, none of the above-mentioned Patent Documents 1 to 4 specifically describe the aforementioned problems, nor do they describe or suggest using a cured layer with a relatively high silicone resin content (mass%) relative to the silicone adhesive layer on the releaseable substrate side, and the technical effects that can be achieved by such a configuration. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Special Publication No. 2010-526931 [Patent Document 2] Special Publication No. 2019-510851

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made to solve the above problems, and has low peeling resistance to a release substrate, particularly a fluorine-free release layer, and is lightly peelable. On the other hand, the adhesive layer after peeling exhibits practically sufficient adhesive force and adhesive strength in applications such as electronic components and flexible displays. An object of the present invention is to provide a release laminate, a method for using the same, and a method for manufacturing the same.

Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that on a substrate provided with a release layer, (LA1) a first silicone-based adhesive layer, and (LA2) a second silicone-based adhesive layer laminated on the same layer, The second silicone-based adhesive layer contains a silicone resin containing a siloxane unit (M unit) represented by the formula: R3SiO 1 / 2 (wherein R is the same or different monovalent organic groups having 1 to 12 carbon atoms) and a siloxane unit (Q unit) represented by the formula: SiO 4 / 2 and the content of the silicone resin is higher than the content of the silicone resin in the first silicone-based adhesive layer, and the thickness of the first silicone-based adhesive layer is thinner than that of the second silicone-based adhesive layer. The present inventors have found that the above problems can be solved by a release laminate including a multilayer silicone-based adhesive layer, and have completed the present invention.

[0008] It is preferable that the above-mentioned first silicone-based adhesive layer and the second silicone-based adhesive layer are integrated. Specifically, it is preferable that the two layers in the present invention are closely adhered and integrated substantially without a gap. In particular, since the silicone resin efficiently migrates from the second silicone-based adhesive layer to the first silicone-based adhesive layer, and the adhesive strength of the surface can be increased over time, when trying to peel the two layers, it is particularly preferable that the two layers are integrated to such an extent that the peeling mode between the two layers is cohesive failure rather than interfacial peeling. Such integration can be preferably achieved by forming the second silicone-based adhesive layer on the same layer after or simultaneously with the formation of the first silicone-based adhesive layer, as described later.

[0009] In practical use, the multi-layer silicone-based adhesive layer according to the present invention is not limited in terms of its thickness and silicone resin content, and it may be used as a thin-layer silicone-based pressure-sensitive adhesive (PSA), or it may be a thick adhesive layer having a stress relaxation and damping prevention function. Further, the content of the silicone resin may be adjusted according to the desired adhesive strength. Specifically, the thickness during coating of the above-mentioned first silicone-based adhesive layer is in the range of 0.3 to 20 μm, the thickness during coating of the above-mentioned second silicone-based adhesive layer is in the range of 3 to 2000 μm, the thickness of the first silicone-based adhesive layer is 1 / 2 or less of the thickness of the second silicone-based adhesive layer, and the content of the silicone resin in the second silicone-based adhesive layer is 20% by mass or more, and the content of the silicone resin in the first silicone-based adhesive layer is preferably in the range of 0 to less than 20% by mass.

[0010] In the releasable laminate according to the present invention, when the multi-layer silicone-based adhesive layer including the first silicone-based adhesive layer is peeled from the above-mentioned release layer and the first silicone-based adhesive layer is adhered to the substrate, it is preferable that the adhesive force of the multi-layer silicone-based adhesive layer to the substrate increases over time.

[0011] The releasable laminate according to the present invention is such that the above-mentioned release layer is a release layer不含fluorine, Preferably, the first silicone-based adhesive layer and the second silicone-based adhesive layer are silicone-based adhesive layers obtained by curing a curable reactive silicone composition that includes at least a hydrosilylation reaction or a peroxide curing reaction.

[0012] In particular, the release laminate according to the present invention comprises the first silicone-based adhesive layer and the second silicone-based adhesive layer, (a) R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 Silicone resin containing siloxane units (Q units) represented by (b) an organopolysiloxane having at least two alkenyl atoms in one molecule, (c) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and (d) a catalyst for hydrosilylation reactions. A silicone adhesive layer obtained by curing a curing-reactive silicone composition containing the following: In the curing reactive silicone composition used to obtain the first silicone adhesive layer, the mass ratio of component (a) / component (b) is in the range of 0 to 0.25, and the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles for every 1 mole of alkenyl groups in component (b). Preferably, the curable reactive silicone composition used to obtain the second silicone adhesive layer has a mass ratio of component (a) / component (b) in the range of 0.25 to 5.0, and the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles for every 1 mole of alkenyl groups in component (b), and contains 30% or more of component (a) when the solid content of the composition is 100% by mass.

[0013] Furthermore, the peelable laminate according to the present invention has the following on the second silicone adhesive layer: (L3) One or more functional layers different from the second silicone adhesive layer. The structure may further consist of multiple layers. Such functional layers may be adhesive layers, release layers, elastic layers such as rubber / elastomer, other non-elastic support layers, optical functional layers, or two or more functional layers consisting of a combination of these.

[0014] The peelable laminate according to the present invention has excellent initial peelability and possesses the property that the adhesive strength of the multilayer silicone adhesive layer to the substrate increases over time after peeling, Step A1: A step of removing the release layer of the releaseable laminate containing the multilayer silicone adhesive layer to expose the first silicone adhesive layer. Step A2: A step of adhering the first silicone adhesive layer exposed in Step A1 to the substrate, and Step A3: A step to increase the adhesive strength between the multilayer silicone adhesive layer and the substrate by leaving the first silicone adhesive layer and the substrate at room temperature to 200°C until the desired adhesive strength is achieved, or by pressurizing them in an atmosphere of approximately 1 to 20 atmospheres. A method of use including this is possible and preferable.

[0015] Furthermore, the object of the present invention can be achieved by a method for manufacturing an electronic component or a display, which includes at least a part of the manufacturing process of the method for using the peelable laminate described above.

[0016] The method for manufacturing a releaseable laminate according to the present invention is not particularly limited, but considering the constraints of the process, timing and flow in the manufacturing process, on a substrate equipped with a release layer, (LA1) First silicone adhesive layer, and (PR1) Substrate having a release layer laminated on the same layer A laminate having the above characteristics may be used in its manufacture. in particular, Step 1': A step of removing the substrate having a release layer laminated on the first silicone adhesive layer from the laminate, thereby exposing the first silicone adhesive layer; Step 2: To form a second silicone adhesive layer on the surface of the first silicone adhesive layer, use the formula: R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 A curable reactive silicone composition (II) containing a silicone resin containing siloxane units (Q units) represented by is applied, and a second silicone adhesive layer is laminated on the first silicone adhesive layer by curing or drying of the composition. A manufacturing method may be provided, characterized in that the content of silicone resin in the second silicone adhesive layer formed in step 2 is higher than the content of silicone resin in the first silicone adhesive layer, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer.

[0017] Similarly, the method for manufacturing a peelable laminate according to the present invention is Step 1: A step of applying a curable reactive silicone composition (I) for forming a first silicone-based adhesive layer onto a substrate having a release layer, and forming the first silicone-based adhesive layer by curing or drying the composition; Step 2: To form a second silicone adhesive layer on the surface of the first silicone adhesive layer, use the formula: R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 A curable reactive silicone composition (II) containing a silicone resin containing siloxane units (Q units) represented by is applied, and a second silicone adhesive layer is laminated on the first silicone adhesive layer by curing or drying of the composition. Comprising, with respect to the content of the silicone resin in the first silicone-based adhesive layer formed in the above-mentioned step 1, the content of the silicone resin in the second silicone-based adhesive layer formed in the above-mentioned step 2 is high, and the thickness of the first silicone-based adhesive layer is thinner than that of the second silicone-based adhesive layer, the coating of each curable reactive silicone composition may be carried out, which may be a manufacturing method characterized by this.

[0018] Regarding the peelable laminate according to the present invention, with respect to the curable reactive silicone composition (I) for forming the first silicone-based adhesive layer, in the curable reactive silicone composition (II) for forming the second silicone-based adhesive layer, the formula: R3SiO 1 / 2 (In the formula, R is the same or different monovalent organic groups having 1 to 12 carbon atoms.) The content of the siloxane unit (M unit) represented by and the siloxane unit (Q unit) represented by the formula: SiO 4 / 2 is selected to be high with respect to the content of the silicone resin in the composition (I), and the coating amount of the curable reactive silicone composition (II) is selected so that the thickness of the first silicone-based adhesive layer is thinner than that of the second silicone-based adhesive layer. It can be preferably manufactured by a design method characterized by this. In particular, the peelable laminate according to the present invention selects a fluorine-free release layer as the release layer, and as the curable reactive silicone composition (I) and the curable reactive silicone composition (II), a curable reactive silicone composition containing a hydrosilylation reaction is selected. It can be preferably manufactured by a design method characterized by this.

[0019] For the production of the peelable laminate according to the present invention, at least (a) R3SiO 1 / 2 (In the formula, R is the same or different monovalent organic groups having 1 to 12 carbon atoms.) The siloxane unit (M unit) represented by and the siloxane unit (Q unit) represented by the formula: SiO 4 / 2 A silicone resin containing (b) an organopolysiloxane having at least two alkenyl atoms in one molecule, (c) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and (d) a catalyst for hydrosilylation reactions. including, and, In a curable reactive silicone composition (I) used to obtain a first silicone-based adhesive layer, the mass ratio of component (a) / component (b) is in the range of 0 to 0.25, and the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles for every 1 mole of alkenyl groups in component (b). In the curable reactive silicone composition (II) used to obtain a second silicone adhesive layer, the mass ratio of component (a) to component (b) is in the range of 0.25 to 5.0, the number of silicon atom-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles per 1 mole of total alkenyl groups in component (b), and the composition contains 30% by mass or more of component (a) when the solid content in the composition is 100% by mass. [Effects of the Invention]

[0020] The present invention provides a release-compatible laminate that exhibits low peel resistance to a release substrate, particularly a fluorine-free release layer, and is easily peelable upon release, while the multilayer silicone adhesive layer increases in adhesive strength and tackiness over time after peeling, resulting in practically sufficient tackiness and adhesive strength for applications such as electronic components and flexible displays. Furthermore, the present invention provides a method for using the release-compatible laminate, and a method for manufacturing an electronic component or display including the method of use. Similarly, the present invention provides a method for manufacturing a release-compatible laminate containing a multilayer silicone adhesive layer, a method for designing the same, and the use of a laminate and a curing reactive silicone composition for the purpose of manufacturing the laminate. [Modes for carrying out the invention]

[0021] [Structure of a releaseable laminate containing a multilayer silicone adhesive layer] The peelable laminate according to the present invention is provided on a substrate having a release layer, (LA1) First silicone adhesive layer, and (LA2) comprises a second silicone adhesive layer laminated on the same layer, The second silicone adhesive layer is formula:R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 The adhesive contains a silicone resin containing siloxane units (Q units) represented by , wherein the content of the silicone resin is higher than the content of the silicone resin in the first silicone adhesive layer, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer, and the first silicone adhesive layer and the second silicone adhesive layer are in close contact without any gaps, preferably having a structure in which both layers are integrated. Furthermore, on the second silicone adhesive layer, (L3) One or more functional layers different from the second silicone adhesive layer. It may also have a further layered structure.

[0022] The release-able laminate of the present invention has a multilayer silicone adhesive layer comprising (LA1) a first silicone adhesive layer and (LA2) a second silicone adhesive layer laminated on the same layer. Here, since the two laminated layers differ in their thickness and silicone resin content, the (LA1) first silicone adhesive layer facing the release-able substrate is easily releaseable, has low peeling resistance during peeling, and allows for smooth separation of the multilayer silicone adhesive layer without causing abnormal noise or damage to the adhesive layer. Furthermore, when the multilayer silicone adhesive layer is brought into close contact with the substrate with the first silicone adhesive layer as the adhesive surface, the silicone resin, which is the adhesion-imparting component, migrates over time from the (LA2) second silicone adhesive layer, which has a large amount of silicone resin and is thick, to the first silicone adhesive layer, which has a small amount of silicone resin and is thinner, due to the concentration gradient between the two layers, and the adhesive strength to the substrate increases over time. This achieves both easy peelability during removal and high adhesive strength when used as an adhesive layer, which were difficult to achieve simultaneously with conventional technologies.

[0023] The multilayer silicone adhesive layer according to the present invention particularly contains the formula: R3SiO in the second silicone adhesive layer. 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 The material contains a silicone resin containing siloxane units (Q units) represented by [formula], and this silicone resin functions as an adhesion-enhancing component, increasing adhesive strength. In this specification, the silicone resin containing these M units and Q units may be simply referred to as "silicone resin".

[0024] In the formula, R is the same or different monovalent organic group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms. Examples of such R include C1 to C12 alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and heptyl groups; C2 to C12 alkenyl groups such as vinyl, allyl, butenyl, and pentenyl groups; C6 to C12 aryl groups such as phenyl, tolyl, and xyl groups; C7 to C12 aralkyl groups such as benzyl and phenethyl groups; and halogen-substituted C1 to C12 alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups, with methyl, vinyl, and phenyl groups being preferred.

[0025] The silicone resin in this invention is of the formula: R3SiO 1 / 2 Siloxane units and formula represented by: SiO 4 / 2 It is a silicone resin consisting of at least one type of siloxane unit represented by the formula SiO, or a mixture of two or more silicone resins. In this silicone resin, the formula is SiO 4 / 2 Formula for siloxane units represented by: R3SiO 1 / 2 The molar ratio of siloxane units represented by is not limited, but is preferably in the range of 0.6 to 2.0, 0.6 to 1.5, 0.6 to 1.1, or 0.7 to 1.0. This is because if this molar ratio is above the lower limit of the above range, the adhesive strength at the adhesive surface to which the silicone resin has migrated increases, and good adhesive properties are imparted.

[0026] This silicone resin, to the extent that it does not impair the purpose of the present invention, is of the formula: R2SiO 2 / 2 Siloxane units and formulas represented by: RSiO 3 / 2 The silicone resin may contain siloxane units represented by the formula. In the formula, R is the same or different monovalent hydrocarbon group having 1 to 12 carbon atoms, and the same groups as described above are examples. Furthermore, the silicone resin may have hydrogen atoms, alkoxy groups such as methoxy groups and ethoxy groups, and hydroxyl groups bonded to the silicon atoms in the molecule, to the extent that it does not impair the purpose of the present invention.

[0027] In the multilayer silicone adhesive layer of the present invention, the silicone resin content is low, and immediately after manufacturing and in the initial stages, the first silicone adhesive layer, which has low peel resistance to the release layer, functions as an easily peelable adhesive surface. On the other hand, as time passes, the silicone resin migrates from the second silicone adhesive layer, increasing the adhesive strength to the substrate over time and achieving practically sufficient adhesive strength. For this reason, it is preferable that the interface between the two layers is tightly in contact without any gaps for the silicone resin to migrate, and it is particularly preferable that the two layers are integrated. Here, "integration" means that the two layers form a strong adhesive state at their interface and do not easily separate. It is particularly preferable that when an attempt is made to peel the first silicone adhesive layer and the second silicone adhesive layer apart at their interface, the two layers do not separate due to interfacial peeling, but rather cohesive failure occurs at the interface between the two layers, and the two layers exhibit peeling behavior as an integrated adhesive layer. In particular, when the two layers adhere tightly together without gaps at their interface, and preferably when the two layers are integrated, the silicone resin efficiently migrates from the second silicone adhesive layer to the first silicone adhesive layer due to the concentration gradient of the silicone resin in the two layers, and the adhesive strength to the substrate tends to increase over time. The integrated layers can be obtained by sequentially coating and curing the curable reactive silicone compositions that form the first and second silicone adhesive layers, or by bonding the first and second silicone adhesive layers, which have been pre-cured from the curable reactive silicone composition, together without creating any gaps.

[0028] Furthermore, if the first silicone-based adhesive layer and the second silicone-based adhesive layer are not laminated, or if a gap or an intermediate layer with a function to hinder the migration of silicone resin is provided between the two layers, the migration of silicone resin to the first silicone-based adhesive layer may be hindered, and the adhesive strength of the adhesive surface, which is the surface of the first silicone-based adhesive layer, to the substrate may not increase sufficiently, making it impossible to achieve the objective of the present invention. Here, the first silicone-based adhesive layer can be formed by applying the same or different curable reactive silicone composition with a low silicone resin content, as described later, once or more times. If desired, two or more curable reactive silicone compositions with a low silicone resin content and different compositions may be applied and cured two or more times to form the first silicone-based adhesive layer. In this case, the adhesive layer formed by the application and curing of two or more curable reactive silicone compositions functions as the first silicone-based adhesive layer as a whole.

[0029] To achieve the technical effects of the present invention, namely easy peelability and increased adhesive strength over time, the first silicone-based adhesive layer must be thinner than the second silicone-based adhesive layer. If the first silicone-based adhesive layer is too thick, the increase in adhesive strength due to the silicone resin migrated from the second silicone-based adhesive layer may be insufficient. Specifically, the thickness of the curing reactive silicone composition used to form the first silicone-based adhesive layer during coating is preferably in the range of 0.3 to 20 μm, and more preferably 0.5 to 15 μm. Furthermore, the thickness of the first silicone-based adhesive layer during coating is preferably 1 / 2 or less of the thickness of the second silicone-based adhesive layer, and particularly preferably 1 / 3 or less, 1 / 4 or less, or 1 / 5 or less.

[0030] The first silicone-based adhesive layer needs to function as an easily peelable adhesive surface with low peel resistance to the release layer, and is characterized by having a lower silicone resin content than the second silicone-based adhesive layer. Specifically, the silicone resin content in the first silicone-based adhesive layer is 0 to less than 20% by mass, and the silicone resin content in the second silicone-based adhesive layer is 20% by mass or more, preferably 30% by mass or more.

[0031] The second silicone adhesive layer has a higher silicone resin content and is thicker than the first silicone adhesive layer, and therefore functions as a source of silicone resin migration in the multilayer silicone adhesive layer. Specifically, due to the concentration gradient of silicone resin between the two layers, silicone resin migrates from the second silicone adhesive layer to the first silicone adhesive layer over time via its interface, increasing the adhesive strength on the surface of the first silicone adhesive layer, which is the bonding surface. This migration of silicone resin proceeds by leaving the surface of the first silicone adhesive layer in close contact with any substrate to be bonded at a temperature of room temperature to 200°C, increasing the adhesive strength and bonding force. In particular, leaving it at a temperature above room temperature may accelerate the migration of silicone resin, resulting in a rapid increase in adhesive strength and bonding force. In practice, it is preferable to leave the first silicone adhesive layer in close contact with the substrate until the bonding strength on the surface of the first silicone adhesive layer, which is the bonding surface, has increased sufficiently.

[0032] Furthermore, the second silicone-based adhesive layer is thicker than the first silicone-based adhesive layer, and if the silicone resin content is high, its thickness can be designed with greater flexibility. It may be an inner layer of a thin-layer pressure-sensitive adhesive (PSA), or it may be a thick functional layer intended for stress relief or damping prevention.

[0033] Specifically, the thickness of the curing reactive silicone composition used to form the second silicone adhesive layer may be in the range of 3 to 2000 μm, and may be a thin layer with a thickness of 3 to 100 μm, or a functional layer with a thickness of 100 to 2000 μm for the purpose of preventing damping or stress relaxation. However, as mentioned above, even when the second silicone adhesive layer is designed to be a thin layer, the thickness of the first silicone adhesive layer during coating is preferably 1 / 2 or less of the thickness of the second silicone adhesive layer. For example, if the thickness of the second silicone adhesive layer during coating is designed to be 3 μm, the thickness of the first silicone adhesive layer during coating is preferably even thinner, in the range of 0.3 to 1.5 μm.

[0034] The release-able laminate according to the present invention has the (LA1) first silicone-based adhesive layer on a substrate equipped with a release layer. Here, the type of release layer is not particularly limited, but the present invention achieves sufficient light release even when conventional release layers containing fluorine are replaced with fluorine-free release layers due to the recent regulations on organofluorine compounds such as PFAS and fluororesins (including fluorosilicone-based release resins), and it is desirable not to use release agents containing fluorine, such as fluorosilicone-based release resins. For example, in Patent Document 4, a polyethylene terephthalate film surface-treated with fluorosilicone is exemplified as a substrate equipped with a suitable release layer, but in the present invention, light release of the multilayer silicone-based adhesive layer can be achieved even with a fluorine-free release layer.

[0035] In the present invention, the substrate having a release layer may be a film substrate having a release layer having release coating ability such as a silicone-based release agent or an alkyd-based release agent. Similarly, the film substrate may have fine physical irregularities formed on its surface, or it may be a film substrate itself that does not easily adhere to the (LA1) first silicone-based adhesive layer of the present invention. From the standpoint of being fluorine-free, it is preferable not to use fluorine-based release agents and fluorosilicone-based release agents.

[0036] The type of film substrate is not particularly limited, and examples include thermoplastic resin films such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polycarbonate, polyethylene terephthalate (PET), nylon, and thermoplastic polyurethane. However, from the standpoint of being fluorine-free, it is preferable not to use fluorine-based resin films such as polytetrafluoroethylene.

[0037] A substrate having such a fluorine-free release layer may be used by applying a release coating agent such as a silicone-based release agent or an alkyd-based release agent to the thermoplastic resin film and curing it to create a thermoplastic resin film with a release coating layer.

[0038] Similarly, thermoplastic resin films that do not contain fluorine and have a release layer on their surface are commercially available in various grades. Examples include, but are not limited to, release PET films from Higashiyama Film Co., Ltd. (Clean Sepa® series), Toray Industries, Inc. (Therapeuil® series), and Daicel Corporation. Commercially available products can be selected and used as the substrate with a release layer in the present invention as desired.

[0039] [(L3) Functional layers of 1 or more layers] As described above, the laminate according to the present invention "Release layer / (LA1) First silicone-based adhesive layer / (LA2) Second silicone-based adhesive layer" The structure is represented by the following: Here, " / " means that the layer on the right is formed on the layer on the left. On the other hand, the laminate according to the present invention may have a structure in which one or more functional layers, different from the second silicone adhesive layer (L3), are further laminated on the second silicone adhesive layer.

[0040] Here, the functional layer (L3) is not particularly limited in terms of its function and type, as long as it is not identical to (LA2). It may be an adhesive layer, a release layer, an elastic layer such as rubber / elastomer, another non-elastic support layer (reinforcement layer), an optical functional layer, a dielectric layer, a conductive layer, a heat dissipation layer, or two or more functional layers consisting of a combination thereof. Furthermore, the functional layer may be made of a silicone-based material or a non-silicone-based material. Examples of silicone-based materials include a silicone release coating layer, a silicone elastomer layer, and a silicone-based adhesive layer (excluding those identical to LA2) obtained by curing a curing reactive silicone composition. Examples of non-silicone-based materials include synthetic resin films / sheets, such as the thermoplastic resin film mentioned above, synthetic rubber, polyethylene laminate paper, natural fiber fabric, synthetic fiber fabric, artificial leather fabric, metal foil, etc. Note that synthetic resin films / sheets, etc., may have a silicone-based release coating layer or other release layer, or an adhesive layer, on any of their surfaces. Furthermore, the functional layer L3 may be an independent article, a part thereof, or a precursor. For example, the functional layer L3 may be part or all of a semiconductor wafer, electronic component, display, or their precursor. When using a film-like substrate as L3, which may optionally have a release layer or an adhesive layer, the film-like substrate (L3), which is the functional layer, can be bonded to the second silicone-based adhesive layer (LA2) using known means such as a roller.

[0041] In the present invention, one or more functional layers (L3) may be provided, so the peelable laminate according to the present invention may have the following configuration represented by the " / " above, and is included in the embodiments of the present invention. However, the configuration of the laminate according to the present invention is not limited to these. Configuration Example 1: Delamination layer / LA1 / LA2 / L3 (Delamination layer) Configuration Example 2: Release layer / LA1 / LA2 / L3-1 (adhesive layer) / L3-2 (release layer) Configuration Example 3: Release layer / LA1 / LA2 / L3 (one or more selected from optical functional layer, elastic layer, and support layer) Configuration Example 4: Release layer / LA1 / LA2 / L3-1 (one or more selected from optical functional layer, elastic layer, and support layer) / L3-2 (adhesive layer) / L3-3 (release layer)

[0042] In the configuration examples 1, 2, and 4 described above, by removing the release layers on both sides of the release laminate according to the present invention, it can be used as a substrate-less double-sided adhesive material that includes a multilayer silicone adhesive layer as part of its composition. Furthermore, in the case of configuration example 3 described above, by removing the release layer on one side of the release laminate according to the present invention, a laminate having a functional layer L3 on its outer surface can be attached to any substrate by L1 (the first silicone adhesive layer).

[0043] As described above, the functional layer (L3) may, if desired, have a low resin content and be a thin silicone adhesive layer, similar to LA1 (the first silicone adhesive layer). If the functional layer (L3) is an adhesive layer similar to LA1 (the first silicone adhesive layer), the functional layer (L3) will also have a low peel resistance initially and be easily peelable, while the silicone resin will migrate from the second silicone adhesive layer (LA2) over time, causing the adhesive force to the substrate to increase over time in the functional layer (L3) as well. In other words, it is possible to design a double-sided adhesive multilayer silicone adhesive layer that has excellent initial peelability and increases in adhesive force to the substrate over time on both sides of the LA2 layer, with low silicone resin content on both sides of the LA1 and L3 surfaces. A typical configuration is as follows. Configuration Example 2': Release layer / LA1 / LA2 / L3-1 (= Adhesive layer similar to LA1) / L3-2 (Release layer)

[0044] The peelable laminate according to the present invention has excellent initial peelability and possesses the property that the adhesive strength of the multilayer silicone adhesive layer to the substrate increases over time after peeling, Step A1: A step of removing the release layer of the releaseable laminate containing the multilayer silicone adhesive layer to expose the first silicone adhesive layer (L1). Step A2: A step of adhering the first silicone adhesive layer (L1) exposed in Step A1 to the substrate, and Step A3: A process to increase the adhesive strength between the multilayer silicone adhesive layer and the substrate by leaving the first silicone adhesive layer (L1) and the substrate at a temperature of room temperature to 200°C until the desired adhesive strength is achieved. A method of use including this is possible and preferable.

[0045] Step A1 refers to the process of peeling off the release layer, which is typically made of a thermoplastic resin film having a release layer, to expose the first silicone-based adhesive layer (L1). Since the first silicone-based adhesive layer (L1) has a low silicone resin content, it exhibits easy peeling, which has the advantage of minimizing noise during initial peeling and reducing the likelihood of damage to the adhesive layer.

[0046] Step A2 is the step of adhering the first silicone adhesive layer (LA1) to the substrate, and means the step of bonding the substrate and the multilayer silicone adhesive layer. Here, the type of substrate is not particularly limited, but examples include some or all of glass, semiconductor wafers, electronic components, displays, and their precursors. In particular, it is preferable to adhere it to a substrate for constructing electronic components or displays.

[0047] Step A3 is a process in which the adhesion between the first silicone adhesive layer (LA1) and the substrate is left at a temperature of room temperature to 200°C until the desired adhesive strength is achieved, thereby increasing the adhesive strength between the multilayer silicone adhesive layer and the substrate. As described above, since the LA1 layer and the LA2 layer have different silicone resin content and thickness, the migration of silicone resin from the LA2 layer to the LA1 layer causes the adhesive strength of the multilayer silicone adhesive layer to the substrate to increase over time after peeling. In particular, leaving it at a temperature above room temperature promotes the migration of silicone resin, and in some cases the adhesive strength and bonding strength to the substrate increase rapidly. As an example, in the multilayer silicone adhesive layer of the present invention, initially the LA1 layer is easily peelable and its peel resistance value is significantly lower than that of the LA2 layer alone. However, by leaving it in contact with the substrate at a temperature of about 70°C for about a day, the migration of silicone resin to the LA1 layer increases the adhesive strength to about 50-90% of the adhesive strength when the LA2 layer alone is in contact with the substrate.

[0048] The method of using the release laminate described above can be widely used in the manufacture of articles involving the bonding of a multilayer silicone adhesive layer and a substrate according to the present invention, and is particularly suitable for use in the manufacture of electronic components or displays, which include this method of use in at least part of the manufacturing process. This is because the method of manufacturing articles including this method of use makes it easy to remove the release layer, and after the bonding of the components / substrates, the adhesive strength and bonding strength of the multilayer silicone adhesive layer can be increased over time, achieving a strong bond. Similarly, the multilayer silicone adhesive layer according to the present invention may be used in the assembly of automotive parts, toys, electronic circuits, or keyboards, and in the construction and use of laminated touchscreens or flat panel displays.

[0049] [Curing reactive silicone composition] The first silicone adhesive layer and the second silicone adhesive layer according to the present invention are obtained by applying a curing-reactive silicone composition, such as hydrosilylation-curable, peroxide-curable, or photocurable, to a substrate having the aforementioned release layer and curing it. Preferably, the use of a curing-reactive silicone composition containing at least a hydrosilylation reaction or a peroxide curing reaction is preferred, and the use of a curing-reactive silicone composition containing a hydrosilylation reaction is preferred.

[0050] Specifically, the first silicone-based adhesive layer and the second silicone-based adhesive layer according to the present invention are provided on a substrate having the release layer, (a) R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 Silicone resin containing siloxane units (Q units) represented by (b) organopolysiloxane having at least two alkenyls in one molecule, (c) organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and (d) Catalyst for hydrosilylation reaction Preferably, the result is obtained by applying and curing a hydrosilylation-curable reactive silicone composition containing [the specified ingredient].

[0051] Component (a) is a silicone resin as described above, and functions as an adhesion-imparting component in the curable reactive silicone composition according to the present invention. A key feature of the present invention is that the content of component (a) differs in the curable reactive silicone composition used to form the first silicone-based adhesive layer and the second silicone-based adhesive layer.

[0052] Component (b) is an organopolysiloxane having at least two alkenyl groups in one molecule. The molecular structure of the component is not limited and includes, for example, linear, partially branched linear, branched, cyclic, and resinous structures, with linear being preferred. (c) Examples of alkenyl groups in component (c) include C2-C12 alkenyl groups such as vinyl groups, allyl groups, butenyl groups, and pentenyl groups, with vinyl groups or hexenyl groups being preferred.

[0053] The bonding position of the alkenyl group in component (b) is not limited and may, for example, be bonded to the silicon atom at the end of the molecular chain and / or within the molecular chain. Examples of groups that bond to silicon atoms other than the alkenyl group in component (b) include C1-C12 alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and heptyl groups; C6-C12 aryl groups such as phenyl, tolyl, and xylyl groups; C7-C12 aralkyl groups such as benzyl and phenethyl groups; and halogen-substituted C1-C12 alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups, with methyl and phenyl groups being preferred.

[0054] Component (c) is an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule. The molecular structure of component (c) is not limited and includes, for example, linear, branched, cyclic, reticular, and partially branched linear structures, with linear being preferred. The bonding positions of the silicon-bonded hydrogen atoms in component (c) are not limited and may, for example, be bonded to silicon atoms at the ends of the molecular chain and / or within the molecular chain. Groups that bond to silicon atoms other than hydrogen atoms in component (c) include, for example, C1-C12 alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups; C6-C12 aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; C7-C12 aralkyl groups such as benzyl and phenethyl groups; and halogen-substituted C1-C12 alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups, with methyl and phenyl groups being preferred. The viscosity of component (c) at 25°C is not limited, but is preferably in the range of 0.1 to 500,000 mPa·s or 1 to 100,000 mPa·s.

[0055] Examples of such component (c) organohydrogenpolysiloxanes include: methylhydrogenpolysiloxane with trimethylsiloxy groups sealed at both ends of the molecular chain; dimethylsiloxane-methylhydrogensiloxane copolymer with trimethylsiloxy groups sealed at both ends of the molecular chain; dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer with trimethylsiloxy groups sealed at both ends of the molecular chain; dimethylpolysiloxane with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain; dimethylsiloxane-methylphenylsiloxane copolymer with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain; methylphenylpolysiloxane with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain; Formula: R 1 3SiO 1 / 2 Siloxane units and formulas represented by; R 1 HSiO 2 / 2 Siloxane units and formula represented by: SiO 4 / 2Organopolysiloxane resin consisting of siloxane units represented by formula: R 1 2HSiO 1 / 2 Siloxane units and formula represented by: SiO 4 / 2 Organopolysiloxane resin consisting of siloxane units represented by formula: R 1 HSiO 2 / 2 Siloxane units and formulas represented by: R 1 SiO 3 / 2 Siloxane units or formulas represented by: HSiO 3 / 2 Examples include organopolysiloxane resins consisting of siloxane units represented by , and mixtures of two or more organohydrogenpolysiloxanes. In the formula, R 1 This refers to a monovalent hydrocarbon group excluding an alkenyl group, and examples of monovalent hydrocarbon groups similar to those described above are given.

[0056] The content of component (c) is not limited, but preferably, in the curable reactive silicone composition, the amount of silicon-bonded hydrogen atoms in component (c) per mole of total alkenyl groups in component (b) (sometimes referred to as the "SiH / Vi ratio" herein) is in the range of 0.5 to 50 moles, 0.6 to 30 moles, or 0.7 to 20 moles. This is because if the content of component (c) is above the lower limit of the above range, the curing of the curable reactive silicone composition proceeds sufficiently, while if it is below the upper limit of the above range, the peel resistance of the silicone adhesive layer obtained from curing the composition tends to be low. On the other hand, if the amount of silicon-bonded hydrogen atoms (SiH groups) in component (c) exceeds the upper limit, the amount of curing agent remaining unreacted increases, which may lead to adverse effects on the cured material's properties, such as brittleness, and problems such as gas generation. However, even if the SiH / Vi ratio of the composition is outside the above range, a practically sufficient silicone adhesive layer can be formed.

[0057] Component (d) is a catalyst for the hydrosilylation reaction to promote the crosslinking reaction of the curing reactive silicone composition. Examples of hydrosilylation catalysts include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts, with platinum-based catalysts being preferred because they can significantly accelerate the curing of the composition. Examples of platinum-based catalysts include platinum fine powder, chloroplatinic acid, an alcoholic solution of chloroplatinic acid, platinum-alkenylsiloxane complexes, platinum-olefin complexes, and platinum-carbonyl complexes, with platinum-alkenylsiloxane complexes being particularly preferred. Examples of this alkenylsiloxane 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 are substituted with groups selected from the group consisting of nitriles, amides, dioxolanes, and sulfolanes, as well as ethyl groups, phenyl groups, etc., and alkenylsiloxanes in which the vinyl groups of these alkenylsiloxanes are substituted with allyl groups, hexenyl groups, etc. In particular, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is preferred because of the good stability of this platinum-alkenylsiloxane complex. As a catalyst to promote the hydrosilylation reaction, non-platinum metal catalysts such as iron, ruthenium, and iron / cobalt may be used.

[0058] The content of component (d) is not limited as long as it is an amount that can carry out the curing reaction of the curing reactive silicone composition, but preferably, the amount of platinum-based metal is in the range of 0.1 to 200 ppm relative to the total amount of solids in the composition, and may be in the range of 0.1 to 150 ppm, 0.1 to 100 ppm, or 0.1 to 50 ppm. This is because if the content of component (d) is above the lower limit of the above range, the curing of the resulting silicone composition (iii) will proceed sufficiently, while if it is below the upper limit of the above range, problems such as discoloration will not occur in the resulting silicone adhesive layer. The solids refer to the components that form the cured layer when the above composition is cured (mainly the main agent, adhesion-enhancing components, crosslinking agents, catalysts, and other non-volatile components), and do not include volatile components such as solvents that volatilize during heat curing.

[0059] [Curing retarder and other optional components] In practice, a curing retarder can be added to the aforementioned curing-reactive silicone composition. The curing retarder is added to suppress the crosslinking reaction between alkenyl groups and SiH groups in the composition, thereby extending the pot life at room temperature and improving storage stability.

[0060] Examples of specific curing retarders include acetylene compounds, enyne compounds, organic nitrogen compounds, organophosphorus compounds, and oxime compounds. Specifically, examples include alkyne alcohols such as 3-methyl-1-butyne-3-ol, 3,5-dimethyl-1-hexyne-3-ol, 3-methyl-1-pentin-3-ol, 1-ethynyl-1-cyclohexanol, and phenylbutynol; enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-1-hexyne-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. Two or more of these curing retarders may be used in combination. The content is not limited, but for practical purposes, it is preferably 5 parts by mass or less per 100 parts by mass of component (b).

[0061] Similarly, the first silicone adhesive layer and the second silicone adhesive layer according to the present invention are provided on a substrate having the release layer, (a) R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 Silicone resin containing siloxane units (Q units) represented by (b) organopolysiloxanes having at least two alkenyls in one molecule, and (e) Organic peroxide It can be obtained by applying and curing a peroxide-curing reactive silicone composition containing [the specified ingredient].

[0062] The silicone resin, which is component (a), and the organopolysiloxane, which is component (b) and the main component, are as described above. The organic peroxide, which is component (e), is a thermal radical initiator that acts as a catalyst to accelerate the curing reaction by heating, and by decomposing and generating oxygen radicals, the peroxide curing reaction of the curing reactive silicone composition containing component (e) proceeds. Specifically, component (e) may be alkyl peroxides, diacyl peroxides, peroxide esters, and peroxide carbonates, and examples include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-bis(2,5-t-butylperoxy)hexane, di-t-butyl peroxide, and t-butyl perbenzoate. These may be used individually or in combination of two or more.

[0063] The content of component (e) is not limited as long as it is in an amount that can carry out the curing reaction of the curing reactive silicone composition. However, in practical terms, when the main component (b) is 100 parts by mass, it is preferably in the range of 0.05 to 10 parts by mass, more preferably in the range of 0.10 to 5.0 parts by mass, and even more preferably in the range of 0.50 to 2.5 parts by mass.

[0064] [organic solvent] The aforementioned curing reactive silicone composition may contain an organic solvent as a solvent. The type and amount of the organic solvent are adjusted considering factors such as coating workability. Examples of 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 Novec, a product of 3M Corporation in the United States. TM Examples of fluorine solvents such as 7200, solvent volatile oils, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and other alkoxysilane compounds are used, and two or more types may be combined depending on the wettability to the sheet-like substrate. The amount of organic solvent should be such that the composition can be uniformly coated onto the surface of the sheet-like substrate, for example, 5 to 3000 parts by mass per 100 parts by mass of the total of components (a) to (c) or components (a) and (b).

[0065] [Optional ingredients] The curing reactive silicone composition described above may optionally contain components other than those listed above, as long as they do not impair the technical effects of the present invention. For example, it may contain: adhesion promoters; non-reactive organopolysiloxanes such as polydimethylsiloxane or polydimethyldiphenylsiloxane; antioxidants such as phenolic, quinone, amine, phosphorus, phosphite, sulfur, or thioether-based antioxidants; light stabilizers such as triazole or benzophenone-based light stabilizers; flame retardants such as phosphate esters, halogens, phosphorus, or antimony-based flame retardants; and one or more antistatic agents such as cationic surfactants, anionic surfactants, or nonionic surfactants. In addition to these components, carbon particles, pigments, dyes, inorganic fine particles (reinforcing fillers, dielectric fillers, conductive fillers, thermally conductive fillers), foaming particles, etc. may also be optionally added.

[0066] Among the aforementioned components, non-reactive organopolysiloxanes refer to polydimethylsiloxanes or polydimethyldiphenylsiloxanes that do not contain reactive groups containing carbon-carbon double bonds such as alkenyl groups, acrylic groups, or methacrylic groups. By incorporating these components into the composition, it may be possible to improve the loss coefficient (tanδ), storage modulus (G'), and loss modulus (G'') of the silicone adhesive layer obtained by curing the curing reactive silicone composition.

[0067] The method for preparing the curing reactive silicone composition for obtaining the silicone adhesive layer according to the present invention is not particularly limited and is carried out by homogeneously mixing each component. A solvent may be added as needed, and the composition may be prepared by mixing at a temperature of 0 to 200°C using a known stirrer or kneader.

[0068] The curing reactive silicone composition forms a coating film when applied to a substrate. In the case of hydrosilylation curing type or peroxide curing type, it can be cured by heating at a temperature of 80 to 200°C, preferably 90 to 190°C, to form a silicone-based adhesive layer. Examples of coating methods include gravure coating, offset coating, offset gravure, roll coating, reverse roll coating, air knife coating, curtain coating, and comma coating. The preferred thickness range for each silicone-based adhesive layer during coating is as described above.

[0069] [Curing reactive silicone composition (I) used to obtain the first silicone-based adhesive layer] A curable reactive silicone composition (I) for forming a first silicone-based adhesive layer, characterized by containing no silicone resin, having a low silicone resin content, and being a thin layer, contains the above-mentioned components (b) to (d), and the mass ratio of component (a) to component (b) is preferably in the range of 0 to 0.25, and may be in the range of 0 to 0.20, 0 to 0.10, or 0 to 0.05. Furthermore, if composition (I) contains component (a), the content of component (a) is preferably in the range of 0 to 20% by mass, 0 to 15% by mass, or 0 to 10% by mass, when the solid content in the composition is 100% by mass. Aside from the silicone resin content, the types of each component, the SiH / Vi ratio, and the temperature conditions for curing in composition (I) are as described above. Furthermore, the first silicone-based adhesive layer obtained by curing composition (I) is a thin layer, and the suitable range of thickness during coating is as described for the thickness of the first silicone-based adhesive layer, including the thickness of composition (I) during coating being in the range of 0.3 to 20 μm.

[0070] [Curing reactive silicone composition (II) used to obtain a second silicone-based adhesive layer] The curable reactive silicone composition (II) (hereinafter sometimes simply referred to as "composition (II)") used to obtain a second silicone-based adhesive layer with a low silicone resin content and thickness contains the above-mentioned components (a) to (d), and the mass ratio of component (a) to component (b) is preferably in the range of 0.25 to 5.0, and this mass ratio may be in the range of 0.5 to 5.0, 0.5 to 4.5, or 0.5 to 4.0. Furthermore, when the solid content in the composition is 100% by mass, the content of component (a) is 30% by mass or more, and is preferably in the range of 30 to 75% by mass or 30 to 65% by mass. Aside from the silicone resin content, the types of each component, the SiH / Vi ratio, and the temperature conditions for curing in composition (II) are as described above. Furthermore, the second silicone-based adhesive layer obtained by curing composition (II) preferably has sufficient thickness, and the suitable range of thickness during coating is as described for the thickness of the second silicone-based adhesive layer, including the thickness of composition (II) during coating being in the range of 3 to 2000 μm.

[0071] [Design method for peelable laminates] The release-able laminate according to the present invention can be suitably manufactured by a design method characterized by selecting a curable reactive silicone composition (II) for forming a second silicone-based adhesive layer in relation to a curable reactive silicone composition (I) for forming a first silicone-based adhesive layer, wherein the silicone resin content in the curable reactive silicone composition (II) for forming a second silicone-based adhesive layer is higher than that in composition (I), and selecting the amount of curable reactive silicone composition (II) applied so that the thickness of the first silicone-based adhesive layer is thinner than that of the second silicone-based adhesive layer. In designing the release-able laminate, it is preferable to select a curable reactive silicone composition that includes a hydrosilylation reaction as the curable reactive silicone composition, and a composition having the above-mentioned silicone resin content may be selected, or a commercially available product capable of forming a silicone-based adhesive layer with a high or low silicone resin content may be selected, and the amount of application may be selected.

[0072] In designing a release-type laminate according to the present invention, it is preferable to select a release layer that does not contain fluorine. Specifically, a thermoplastic resin film that does not contain fluorine and has a release layer on its surface, particularly a commercially available product thereof, can be selected.

[0073] [Method for manufacturing a peelable laminate] The method for manufacturing the peelable laminate according to the present invention is not particularly limited, and the manufacturing process may be carried out in a single manufacturing facility, or it may be carried out in multiple stages or multiple manufacturing facilities, taking into consideration the commercial flow of the product.

[0074] [Manufacturing method A] The peelable laminate according to the present invention is Step 1: A step of applying a curable reactive silicone composition (I) for forming a first silicone-based adhesive layer onto a substrate having a release layer, and forming the first silicone-based adhesive layer by curing or drying the composition; Step 2: To form a second silicone adhesive layer on the surface of the first silicone adhesive layer, use the formula: R3SiO 1 / 2 Siloxane units (M units) represented by the formula: SiO 4 / 2 A curable reactive silicone composition (II) containing a silicone resin containing siloxane units (Q units) represented by is applied, and a second silicone adhesive layer is laminated on the first silicone adhesive layer by curing or drying of the composition. The present invention can be obtained by a manufacturing method characterized by coating each curable reactive silicone composition such that the content of silicone resin in the second silicone adhesive layer formed in step 2 is higher than the content of silicone resin in the first silicone adhesive layer formed in step 1, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer. This manufacturing method is particularly suitable for manufacturing the releaseable laminate according to the present invention in a laboratory or a single manufacturing facility.

[0075] Step 1 is a step of forming a first silicone-based adhesive layer on the release layer, and the substrate equipped with the release layer, the curing reactive silicone composition (I), its coating, and curing method in this step are as described above. Furthermore, the relationship between the coating thickness of the first silicone-based adhesive layer formed in Step 1 and the coating thickness of the second silicone-based adhesive layer formed in Step 2 is as described above.

[0076] Step 2 is a step in which a curable reactive silicone composition (II) with a high silicone resin content is applied to the surface of the first silicone adhesive layer to a thickness greater than that of the first silicone adhesive layer, and a second silicone adhesive layer is laminated by curing the composition. The curable reactive silicone composition (II) in this step, its application, and curing method are as described above. Furthermore, in this manufacturing method, the thickness of the second silicone adhesive layer during application can be designed with a high degree of freedom in relation to its function, and the range of suitable thicknesses is as described for the thickness of the second silicone adhesive layer.

[0077] [Method of using and manufacturing laminates B] The peelable laminate according to the present invention may be manufactured in stages at multiple manufacturing facilities, in which case the adhesive layer is protected while transporting it between manufacturing facilities. On a substrate equipped with a release layer, (LA1) First silicone adhesive layer, and (PR1) Substrate having a release layer laminated on the same layer A laminate having the above characteristics can be used. The use of the precursor (laminated material) for the purpose of manufacturing a releaseable laminate according to the present invention is included in the scope of the present invention. By providing a releaseable substrate (PR1) on the first silicone adhesive layer, damage to the adhesive layer and surface contamination by dust can be prevented during transportation between manufacturing facilities, and by removing the releaseable substrate (PR1), the first silicone adhesive layer can be exposed and used in the subsequent lamination process of the second silicone adhesive layer. As mentioned above, the first silicone adhesive layer has a small amount of silicone resin and is easily releaseable, so it has the advantage of being less likely to cause damage to the adhesive surface or abnormal noise when the releaseable substrate (PR1) is removed, and also has a small release resistance value.

[0078] The substrate (PR1) having a release layer laminated on the first silicone adhesive layer is not particularly limited, and examples include a thermoplastic resin film (including commercially available products) having a release layer on its surface.

[0079] Such a laminate can be obtained by applying a curable reactive silicone composition (I) for forming a first silicone adhesive layer onto a substrate having a release layer, similar to step 1 of [Manufacturing Method A], forming the first silicone adhesive layer by curing or drying the composition, and then laminating a substrate (PR1) having a release layer onto the surface of the first silicone adhesive layer. This laminate can be commercially traded as a precursor to the release laminate according to the present invention and can be used by shipping or transporting it to a manufacturing facility different from the manufacturer.

[0080] The peelable laminate according to the present invention can be used in the following manufacturing methods using the laminate. Specifically, Step 1': A step of removing the substrate having a release layer laminated on the first silicone adhesive layer from the laminate, thereby exposing the first silicone adhesive layer; Step 2: To form a second silicone adhesive layer on the surface of the first silicone adhesive layer, use the formula: R3SiO 1 / 2Siloxane units (M units) represented by the formula: SiO 4 / 2 A curable reactive silicone composition (II) containing a silicone resin containing siloxane units (Q units) represented by is applied, and a second silicone adhesive layer is laminated on the first silicone adhesive layer by curing or drying of the composition. The manufacturing method is characterized by coating a curable reactive silicone composition (II) such that the content of silicone resin in the second silicone-based adhesive layer formed in step 2 is higher than the content of silicone resin in the first silicone-based adhesive layer, and the thickness of the first silicone-based adhesive layer is thinner than that of the second silicone-based adhesive layer.

[0081] Step 1' is the step of removing from the laminate a substrate (PR1) having a release layer laminated on the first silicone adhesive layer, thereby exposing the first silicone adhesive layer. The subsequent step 2 is the step of forming a second silicone adhesive layer on the surface of the first silicone adhesive layer, and is the same as step 2 above.

[0082] [Additional process] After forming a release laminate including a multilayer silicone adhesive layer represented by “release layer / first silicone adhesive layer / second silicone adhesive layer” by either of the above manufacturing methods (A or B), the method may further include a step of laminating one or more functional layers different from the second silicone adhesive layer onto the second silicone adhesive layer (L3). For example, a substrate with a release layer may be attached to the second silicone adhesive layer and laminated, or a curable reactive composition that forms an adhesive layer or elastic layer by curing may be applied to the second silicone adhesive layer and cured to form an adhesive layer or elastic layer. When forming the adhesive layer, known methods, including the coating and curing method of the curable reactive silicone composition in the present invention, may be appropriately selected. Furthermore, a film or sheet which is an optical functional layer may be laminated onto the second silicone adhesive layer or onto the functional layer formed thereon, or some or all of semiconductor wafers, electronic components, displays, or their precursors may be laminated.

[0083] [Uses as adhesive layers, pressure-sensitive adhesive layers, and elastic adhesive members] As described above, the release-able laminate according to the present invention allows the first silicone-based adhesive layer, which has low peel resistance to the release layer immediately after manufacturing and in the initial stages, to function as an easily peelable adhesive surface. At the same time, as the silicone resin migrates from the second silicone-based adhesive layer over time, the adhesive strength to the substrate increases over time, achieving practically sufficient adhesive strength. Therefore, it can be used to replace known adhesive layers and pressure-sensitive adhesive layers. Furthermore, depending on the configuration of the multilayer silicone-based adhesive layer, it is possible to design an adhesive layer having a desired adhesive strength, shear storage modulus (G') at room temperature or low temperature (-20°C), glass transition temperature (Tg) measured by differential calorimeter (DSC), and in particular, the glass transition temperature (Tg) as the peak value of the loss tangent (tanδ) obtained by [shear loss modulus / shear storage modulus].

[0084] The multilayer silicone adhesive layer described above can be designed to be substantially transparent, translucent, or opaque, depending on the compositional selection of the first silicone adhesive layer, the second silicone adhesive layer, and other functional layers, and their applications. For example, when used as a pressure-sensitive adhesive layer for display devices, a multilayer silicone adhesive layer with a thickness of 10 to 1000 μm is preferably transparent to the naked eye and preferably does not contain coloring additives such as carbon black. More objectively, if it is transparent to the naked eye, the light transmittance of a multilayer silicone adhesive layer for display devices consisting of a 100 μm thick cured layer at a wavelength of 450 nm should be 80% or more, preferably 90% or more, and may be designed to be 95% or more, with the value of air being 100%. On the other hand, for bonding electrical and electronic components where light transmittance is not required, a translucent to opaque multilayer silicone adhesive layer may be used, and coloring or filler components or additives that impair light transmittance may be used depending on the required characteristics other than light transmittance. Furthermore, the above-mentioned multilayer silicone adhesive layer can also be designed to be colorless in addition to transparent, by reducing the content of platinum-based metals used for curing.

[0085] The multilayer silicone adhesive layer described above may also be assigned the role of other functional layers selected from among optical functional layers, dielectric layers, conductive layers, heat dissipation layers, insulating layers, support layers (reinforcement layers), etc., in addition to providing adhesive or bonding functions between components.

[0086] The multilayer silicone adhesive layer described above is easily peelable initially, and its adhesive strength increases after it adheres to the substrate. Furthermore, its configuration allows for practically sufficient viscoelasticity, making it suitable for use in the construction and use of laminated touchscreens or flat panel displays. Its specific use is not limited to known uses of pressure-sensitive adhesive layers (especially silicone PSA). Similarly, the multilayer silicone adhesive layer is useful as an elastic adhesive member for various electronic or electrical devices. In particular, it is useful as an electronic material, a display device component, or a transducer component (including those for sensors, speakers, actuators, and generators), and a preferred application for this multilayer silicone adhesive layer is as a component of electronic components or display devices. The multilayer silicone adhesive layer according to the present invention may be transparent or opaque, but a cured film, especially a substantially transparent pressure-sensitive adhesive film, is suitable as a component for display panels or displays, and is particularly useful for so-called touch panel applications where devices, especially electronic devices, can be operated by touching the screen with a fingertip or the like. Furthermore, the opaque multilayer silicone adhesive layer can also be used in applications such as sensors, speakers, actuators, and other film-like or sheet-like components where transparency is not required and a certain degree of elasticity or flexibility in the adhesive layer itself is necessary.

[0087] The multilayer silicone adhesive layer according to the present invention may be used to replace part or all of the pressure-sensitive adhesive layers disclosed in the international publication brochures proposed by the applicant (WO / 2020 / 032285, WO / 2020 / 032286, WO / 2020 / 032287), and the applications of the pressure-sensitive adhesive layers disclosed in these documents are included in applications in which the multilayer silicone adhesive layer according to the present invention can be suitably used. [Examples]

[0088] The releaseable laminate containing the multilayer silicone adhesive layer of the present invention will be described in detail with reference to examples and comparative examples. In each example and comparative example, "cured" means that each composition has been completely cured under the respective curing conditions, and the viscosity is the value at 25°C. The plasticity is the value obtained when a 1 kgf load is applied to a 4.2 g spherical sample at 25°C for 3 minutes, in accordance with the method specified in JIS K 6249.

[0089] [Substrate with a release layer: commercially available release film] In the examples and comparative examples of the present invention, commercially available release films that do not contain fluorine atoms were used as substrates equipped with a release layer. In the examples, these release substrates are indicated by abbreviations. Abbreviation "NS-35": Release PET film, Model number: HY-NS35 (Manufactured by Higashiyama Film Co., Ltd.) Abbreviation "PJ271": Release PET film, Model number: Therapyle(R) PJ271 (manufactured by Toray Industries, Inc.) Abbreviation "T0157": Release PET film, Model number: T0157 (Manufactured by Daicel Corporation) Note: In the creation of the peelable laminate in the example, a PET film (manufactured by Toray Industries, Inc., product name Lumirror® S10, thickness 50 μm) is laminated at the end, but this is not a substrate with a release layer and is not the surface on which peel resistance testing is performed.

[0090] [Peel Resistance Test] After preparing the peelable laminates (test specimens) shown in the Examples / Comparative Examples, they were cut into strips 2.5 cm wide. These specimens were subjected to a peel resistance test using a tensile testing machine [Tensilon universal testing machine manufactured by A&D Co., Ltd.] (hereinafter referred to as "Tensilon") at 25°C, a peeling speed of 0.3 m / min, and 180 degrees Celsius by peeling off the peelable substrate. The results are shown in Table 1.

[0091] [Adhesion Test] <70℃-1 day later> Next, the silicone adhesive layer exposed by peeling off the release substrate from the test specimen used in the peel resistance test described above was attached to a 2 mm thick glass plate, and pressed down by passing a 2 kg rubber roller back and forth twice. The specimen with the adhesive layer attached to the glass plate was stored at 70°C for one day, and then the test specimen was peeled off from the glass plate using a Tensilon at 25°C and a peeling speed of 0.3 m / min, and an adhesion strength test was performed at 180°C. The results are shown in Table 1. <25℃ - 1 hour later (initial adhesive strength)> Using the same method as above, the silicone adhesive layer exposed by peeling off the release substrate was pressed onto a glass plate, stored at 25℃ for 1 hour (i.e., without waiting for the adhesive strength to change over time), and this test specimen was peeled off the glass plate with a Tensilon at 25℃ and a peeling speed of 0.3 m / min, and an adhesive strength test was performed at 180 degrees.

[0092] [Preparation of curing reactive silicone composition (P-Ia) (hereinafter referred to as "coating solution (P-Ia)")] 99 parts by mass of dimethylpolysiloxane having vinyl groups at the terminals (vinyl group content 0.013% by mass), 0.2 parts by mass of 1-ethynyl-1-cyclohexanol (ETCH), and 1.0 part by mass of dimethylmethylhydrogenpolysiloxane having silicon-bonded hydrogen atoms in the side chains and part of the terminals (Si-H content 0.43% by mass) (the amount such that the molar ratio of silicon-bonded hydrogen atoms in this component to vinyl groups in the dimethylpolysiloxane is 9) were mixed in a toluene:heptane mass ratio of 1:1 to adjust the solid content to 17.5% by mass, and a platinum-based catalyst (SRX 212 CATALYST manufactured by Toray Dow Corning Co., Ltd.) was added in an amount equivalent to a platinum metal content of 260 ppm to obtain coating solution (P-Ia). The coating liquid (P-Ia) has a SiH / Vi ratio of 9, and upon curing, it forms a silicone-based adhesive layer (cured layer) that does not contain silicone resin.

[0093] [Preparation of curing reactive silicone composition (P-Ib) (hereinafter referred to as "coating solution (P-Ib)")] In coating solution (P-Ia), the amount of dimethylhydrogenpolysiloxane (Si-H content 0.43% by mass), which has silicon-bonded hydrogen atoms in its side chains and some of its terminals, was changed to an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component to vinyl groups in the dimethylpolysiloxane is 11. Otherwise, coating solution (P-Ib) was obtained in the same manner as coating solution (P-Ia). This coating solution (P-Ib) has a SiH / Vi ratio of 11 and, upon curing, forms a silicone-based adhesive layer (cured layer) that does not contain silicone resin.

[0094] [Preparation of curing reactive silicone composition (P-Ic) (hereinafter referred to as "coating liquid (P-Ic)")] In coating solution (P-Ia), 1.0 part by mass of dimethylhydrogenpolysiloxane (Si-H content 0.43% by mass) having silicon-bonded hydrogen atoms in part of the side chains and terminals is replaced with dimethylmethylhydrogenpolysiloxane (Si-H content 1.03% by mass) having silicon-bonded hydrogen atoms in part of the side chains and terminals. Coating solution (P-Ic) was obtained in the same manner as coating solution (P-Ia), except that 0.93 parts by mass (an amount such that the molar ratio of silicon atom-bonded hydrogen atoms in this component to vinyl groups in the dimethylpolysiloxane above is 20) was added. This coating solution (P-Ic) has a SiH / Vi ratio of 20 and, upon curing, forms a silicone-based adhesive layer (cured layer) that does not contain silicone resin.

[0095] [Preparation of curing reactive silicone composition (P-II) (hereinafter referred to as "coating liquid (P-II)")] 33 parts by mass of dimethylpolysiloxane with dimethyl vinylsiloxy groups sealed at both ends of the molecular chain, with a plasticity of 135, formula: (CH3)3SiO 1 / 2 Siloxane units and formula represented by: SiO 4 / 2 It consists of siloxane units represented by the formula: SiO 4 / 2 Formula for the siloxane unit represented by: (CH3)3SiO 1 / 2A coating solution (P-II) was prepared by mixing 72 parts by mass of a xylene solution (solid content = 64% by mass) of a silicone resin containing 1% by mass of silicon atom-bonded hydroxyl groups, with a molar ratio of siloxane units represented by 0.9, 0.3 parts by mass of methylhydrogenpolysiloxane with trimethylsiloxy groups sealed at both ends of the molecular chain and a viscosity of 20 mPa·s (an amount such that the molar ratio of silicon atom-bonded hydrogen atoms in this component to vinyl groups in the above dimethylpolysiloxane is 22), 0.3 parts by mass of a mixture of 3,5-dimethyl-3-hexen-1-yne and 2-isobutyl-1-buten-3-yne, 92 parts by mass of toluene, and 0.9 parts by mass of a platinum-based catalyst (SRX 212 CATALYST manufactured by Toray Dow Corning Co., Ltd.) (an amount such that the platinum metal content is approximately 50 ppm) at room temperature. The silicone resin content in the silicone composition of this coating solution was 58% by mass. The coating liquid (P-II) hardens to form a silicone-based adhesive layer (cured layer) with a high silicone resin content.

[0096] [Example 1: Preparation of a peelable laminate P1] Step 1: On the release film NS-35, coating liquid P-1a was applied using OSP A BAR#52 so that the coating thickness after curing would be 5 μm. It was then dried and cured in an oven at 130°C for 2 minutes to form a silicone adhesive layer (LA-p1) on the NS-35. Step 2: On the silicone adhesive layer (LA-p1) obtained in Step 1, coating liquid P-2 was applied using a Baker-type film applicator so that the coating thickness after curing would be 50 μm. The mixture was then dried and cured in an oven at 130°C for 2 minutes to form a silicone adhesive layer (LA-p2). Step 3: A PET film (L3) (manufactured by Toray Industries, Inc., product name Lumirror® S10, thickness 50 μm) was laminated onto the silicone adhesive layer (LA-p2) obtained in Step 2 using a roller to create a peelable laminate P1.

[0097] [Example 2: Preparation of a peelable laminate P2] In Example 1, a peelable laminate P2 was prepared in the same manner as before, except that coating solution P-1b with a SiH / Vi ratio of 11 was used instead of coating solution P-1a (SiH / Vi ratio = 9).

[0098] [Comparative Example 1: Preparation of Peelable Laminate C1] Without forming a silicone adhesive layer (LA-p1), coating liquid P-2 was applied onto the release film NS-35 using a baker-type film applicator to a cured coating thickness of 50 μm. The coating was then dried and cured in a 130°C oven for 2 minutes to form a silicone adhesive layer (LA-p2). A PET film (L3) (manufactured by Toray Industries, Inc., product name Lumirror® S10, thickness 50 μm) was then laminated onto the silicone adhesive layer (LA-p2) using a roller to create a release laminate C1.

[0099] [Example 3: Preparation of a peelable laminate P3] In Example 1, step 1 was modified as follows. Step 1: On the release film PJ271, coating liquid P-1c was applied using OSP A BAR#15 so that the coating thickness after curing would be 1.5 μm. It was then dried and cured in an oven at 130°C for 2 minutes to form a silicone adhesive layer (LA-p1) on PJ271. The subsequent steps were carried out in the same manner as in Example 1 to create the peelable laminate P3.

[0100] [Comparative Example 2: Preparation of Peelable Laminate C2] In Comparative Example 1, a release film PJ271 was used instead of release film NS-35, and the same procedure was followed to create a release laminate C2.

[0101] [Example 4: Preparation of a peelable laminate P4] In Example 1, step 1 was modified as follows. Step 1: On the release film T0157, coating liquid P-1c was applied using OSP A BAR#25 so that the coating thickness after curing would be 2 μm. It was then dried and cured in an oven at 130°C for 2 minutes to form a silicone adhesive layer (LA-p1) on T0157. The subsequent steps were carried out in the same manner as in Example 1 to create the peelable laminate P4.

[0102] [Comparative Example 3: Preparation of Peelable Laminate C3] In Comparative Example 1, a release film T0157 was used instead of release film NS-35 to create a release laminate C3, in the same manner as in the previous example.

[0103] [Variations in the manufacturing process for each embodiment] In Example 1, after forming a silicone adhesive layer (LA-p1) on NS-35 (release film) in step 1, an arbitrary release film (PR1) can be bonded to the silicone adhesive layer (LA-p1) to form a laminate for manufacturing a release laminate according to the present invention. After transporting the laminate to a manufacturing location for the next step, the release film (PR1) is removed to expose the silicone adhesive layer (LA-p1), and the subsequent step 2, etc., can be performed to create the release laminate P1 according to Example 1. Similar variations of the manufacturing process are possible in other examples.

[0104] [Example: Preparation of a peelable laminate P4] As described below, it is possible to create a peelable laminate P4 having release film NS-35 on both sides, and it can be evaluated by peel resistance tests and adhesive strength tests similar to those described above. Step (1): In the same manner as in Steps 1 and 2 of Example 1, a laminate P4-1 having a silicone adhesive layer (LA-p1) on NS-35 and a laminated silicone adhesive layer (LA-p2) on top of it was formed by applying coating liquid P-II and curing it. Step (2): A silicone adhesive layer (LA-p1) was formed on NS-35 in the same manner as in Step 1 of Example 1, and laminate P4-L3 was created. Note that the silicone adhesive layer (LA-p1) is a cured layer. Step (3): The silicone adhesive layer (LA-p2) surface of laminate P4-1 and the silicone adhesive layer (LA-p1) of laminate P4-L3 were bonded together using a roller to create a release laminate P4. This release laminate is a double-sided release laminate because it has the following configuration. Here, (W) represents the coated surface in step (1), and (D) represents the bonded surface in step (3). “NS-35 / LA-p1(W) / LA-p2 / (D)LA-p1 / NS-35”

[0105] [Variations of the example] The release film in the reference example can be replaced with other release films containing NS-35 to T0157 or PJ271 on one or both sides. Furthermore, the coating liquid P-1a used to form the silicone adhesive layer LA-p1, which does not contain silicone resin, may be replaced with the aforementioned coating liquid P-1b or coating liquid P-1c, and its thickness can be freely designed within a range where the coated thickness after curing is thinner than the coated thickness of the silicone adhesive layer (LA-p2) (=50 μm).

[0106] [Table 1: Initial peelability and adhesive strength over time for Examples 1-4 and Comparative Examples 1-3] [Table 1] (*1) SiH / Vi ratio and cured coating thickness (μm) of the coating solution used to form a silicone-based adhesive layer without silicone resin on a release film. (*2) Comparative Examples 1-3: These do not have a silicone-based adhesive layer (LA-p1) that does not contain silicone resin on the release film. Therefore, a silicone-based adhesive layer (LA-p2) is directly formed on each release film.

[0107] [Example 5-1: Preparation and evaluation of peelable laminate P5] Step (1): In the same manner as in Steps 1 and 2 of Example 2 (SiH / Vi ratio = 11), a laminate P5-1 having a silicone adhesive layer (LA-p1) on a release film NS-35 and a laminated silicone adhesive layer (LA-p2) on top of that by applying and curing coating liquid P-II. Step (2): A release film PJ271 was bonded to the silicone adhesive layer (LA-p2) obtained in step (1) using a roller to create a double-sided peelable laminate P5. For reference, the configuration of laminate P5 is as follows: P5 configuration: [NS-35] / LA-p1 / LA-p2 / [PJ271]

[0108] After preparing the double-sided release laminate P5, it was left to stand at 70°C for one day and then cut into strips 2 cm wide. Using a Tensilon machine, a peel resistance test was performed on these specimens by peeling the release film PJ271 from the adhesive layer (LA-p2) corresponding to the heavy release surface at 25°C, a peeling speed of 1 m / min, and 180 degrees. The results are shown in Table 2.

[0109] Next, the exposed adhesive layer (LA-p2) was attached to a 2 mm thick glass plate and pressed down by rolling a 2 kg rubber roller back and forth twice. The adhesive layer was then stored at 23°C for one day. Subsequently, a peel resistance test was performed on this specimen by peeling off the release film NS-35 from the adhesive layer (LA-p1) corresponding to the easily peelable surface at 25°C, a peeling speed of 1 m / min, and 180 degrees. The results are shown in Table 2.

[0110] Two of the above test specimens were prepared, and for each, a PET film (manufactured by Toray Industries, Inc., product name Lumirror® S10, thickness 50 μm) was attached to the exposed silicone adhesive layer (LA-p1) using a roller to create two test specimens for adhesion strength measurement. One of the two test specimens was left to stand at 23°C for 1 hour, and the other at 70°C for 1 day. Then, they were peeled off the glass plate using a Tensilon at 25°C and a peeling speed of 0.3 m / min, and an adhesion strength test was performed at 180°C. The results are shown in Table 2.

[0111] [Example 5-2: Preparation and evaluation of peelable laminate P6] In the same procedure as in Example 5-1, except that a silicone adhesive layer (LA-p1) was applied to the release film NS-35 so that the cured coating thickness was 8 μm, a double-sided peelable laminate P6 was prepared, and peel resistance tests and adhesive strength tests were performed. The results are shown in Table 2. [Table 2] (*1) SiH / Vi ratio and cured coating thickness (μm) of the coating solution used to form a silicone-based adhesive layer without silicone resin on a release film.

[0112] [Summary] As shown in Table 1, the peelable laminate containing the multilayer silicone adhesive layer according to the example exhibited a significantly reduced peel resistance compared to the case where a silicone adhesive layer (LA-p2) containing a large amount of silicone resin was directly formed on the release film. Furthermore, no abnormal noise or damage to the adhesive layer occurred during peeling, and the surface of the multilayer silicone adhesive layer was easily peelable. Moreover, by pressing the multilayer silicone adhesive layer onto a glass plate and leaving it at 70°C for one day, it achieved practically comparable adhesive strength to the comparative example's silicone adhesive layer (LA-p2). This trend was consistent regardless of which release film was selected for the experiment. Therefore, it was confirmed that the configuration of the peelable laminate according to the present invention allows for both initial easy peeling and practically sufficient adhesive strength over time in the multilayer silicone adhesive layer.

[0113] As shown in Table 2, the release laminates containing the multilayer silicone adhesive layer according to the examples exhibit sufficiently low peel resistance and easy peelability, even when the silicone adhesive layer (LA-p1) without silicone resin has a thickness of 5 μm or 8 μm. On the other hand, when these multilayer silicone adhesive layers were bonded to a PET film on the silicone adhesive layer (LA-p1) side without silicone resin, it was confirmed that the adhesive strength increased significantly after 70°C for 1 day compared to 23°C for 1 hour. It was also confirmed that practical initial adhesive strength was achieved even after a relatively short time of 23°C for 1 hour. From this, it was confirmed that the multilayer silicone adhesive layer and the release laminate containing it according to the present invention exhibit excellent initial peelability, and that practically sufficient adhesive strength can be achieved not only to glass but also to resin substrates such as PET, both initially and over time.

Claims

1. On a substrate equipped with a release layer, (LA1) First silicone adhesive layer, and (LA2) comprising a second silicone-based adhesive layer laminated on the same layer, The second silicone adhesive layer is formula: R ３ SiO １／２ Siloxane units (M units) represented by the formula: SiO ４／２ A releaseable laminate containing a multilayer silicone adhesive layer, characterized in that it contains a silicone resin containing siloxane units (Q units) represented by , the content of the silicone resin is higher than the content of the silicone resin in the first silicone adhesive layer, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer.

2. A peelable laminate comprising a multilayer silicone adhesive layer according to claim 1, characterized in that the first silicone adhesive layer and the second silicone adhesive layer are integrated.

3. The thickness of the first silicone-based adhesive layer during coating is in the range of 0.3 to 20 μm. A peelable laminate comprising a multilayer silicone adhesive layer according to claim 1, wherein the thickness of the second silicone adhesive layer at the time of coating is in the range of 3 to 2000 μm, the thickness of the first silicone adhesive layer is 1 / 2 or less of the thickness of the second silicone adhesive layer, the silicone resin content in the second silicone adhesive layer is 20% by mass or more, and the silicone resin content in the first silicone adhesive layer is in the range of 0 to less than 20% by mass.

4. The peelable laminate containing a multilayer silicone adhesive layer according to claim 1, characterized in that when the multilayer silicone adhesive layer containing the first silicone adhesive layer is peeled from the aforementioned release layer and the first silicone adhesive layer is brought into close contact with the substrate, the adhesive force of the multilayer silicone adhesive layer to the substrate increases over time.

5. The aforementioned release layer is a release layer that does not contain fluorine. A peelable laminate comprising a multilayer silicone adhesive layer according to claim 1, wherein the first silicone adhesive layer and the second silicone adhesive layer are silicone adhesive layers obtained by curing a curable reactive silicone composition comprising at least a hydrosilylation reaction or a peroxide curing reaction.

6. The first silicone adhesive layer and the second silicone adhesive layer are at least (a) R ３ SiO １／２ Siloxane units (M units) represented by the formula: SiO ４／２ A silicone resin containing siloxane units (Q units) represented by (b) an organopolysiloxane having at least two alkenyl atoms in one molecule, (c) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and (d) a catalyst for hydrosilylation reactions. A silicone adhesive layer obtained by curing a curing-reactive silicone composition containing the following: In the curing reactive silicone composition used to obtain the first silicone adhesive layer, the mass ratio of component (a) to component (b) is in the range of 0 to 0.25, and the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles for every 1 mole of alkenyl groups in component (b). In a curable reactive silicone composition used to obtain a second silicone adhesive layer, the mass ratio of component (a) to component (b) is in the range of 0.25 to 5.0, the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles per mole of total alkenyl groups in component (b), and the composition contains 30% or more of component (a) when the solid content of the composition is 100% by mass. A peelable laminate comprising a multilayer silicone adhesive layer as described in claim 1.

7. On the aforementioned second silicone adhesive layer, (L3) One or more functional layers different from the second silicone-based adhesive layer. A peelable laminate containing a multilayer silicone adhesive layer having a further layered structure.

8. Step A1: A step of removing the release layer of a releaseable laminate containing a multilayer silicone adhesive layer according to any one of claims 1 to 7, to expose the first silicone adhesive layer. Step A2: A step of adhering the first silicone adhesive layer exposed in Step A1 to the substrate, and Step A3: A step to increase the adhesive strength between the multilayer silicone adhesive layer and the substrate by leaving the first silicone adhesive layer and the substrate at a temperature of room temperature to 200°C until the desired adhesive strength is achieved. A method for using a release laminate containing a multilayer silicone adhesive layer having the following properties.

9. A method for manufacturing an electronic component or a display, comprising at least a method for using a releaseable laminate containing a multilayer silicone adhesive layer as described in claim 8, as part of its manufacturing process.

10. A laminate used for manufacturing a releaseable laminate comprising a multilayer silicone adhesive layer according to any one of claims 1 to 7, wherein a substrate having a release layer is provided, (LA1) First silicone adhesive layer, and (PR1) Substrate having a release layer laminated on the same layer A laminate having the following characteristics.

11. Step 1: A step of applying a curable reactive silicone composition (I) for forming a first silicone-based adhesive layer onto a substrate having a release layer, and forming the first silicone-based adhesive layer by curing or drying the composition; Step 2: In order to form a second silicone-based adhesive layer on the surface of the first silicone-based adhesive layer, a curable reactive silicone composition (II) containing a silicone resin containing a siloxane unit (M unit) represented by the formula: R ３ SiO １／２ (wherein R is the same or different monovalent organic groups having 1 to 12 carbon atoms) and a siloxane unit (Q unit) represented by the formula: SiO ４／２ is applied, and a second silicone-based adhesive layer is laminated on the first silicone-based adhesive layer by curing or drying the composition A method for producing a peelable laminate containing a multilayer silicone adhesive layer according to any one of claims 1 to 7, characterized in that the content of silicone resin in the second silicone adhesive layer formed in step 2 is higher than the content of silicone resin in the first silicone adhesive layer formed in step 1, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer.

12. Step 1': A step of removing a substrate having a release layer laminated on the first silicone adhesive layer from the laminate according to claim 10, thereby exposing the first silicone adhesive layer; Step 2: To form a second silicone adhesive layer on the surface of the first silicone adhesive layer, use formula: R ３ SiO １／２ Siloxane units (M units) represented by the formula: SiO ４／２ A curable reactive silicone composition (II) containing a silicone resin containing siloxane units (Q units) represented by is applied, and a second silicone adhesive layer is laminated on the first silicone adhesive layer by curing or drying of the composition. A method for producing a releaseable laminate containing a multilayer silicone adhesive layer according to any one of claims 1 to 7, characterized in that the content of silicone resin in the second silicone adhesive layer formed in step 2 is higher than the content of silicone resin in the first silicone adhesive layer, and the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer.

13. A curable reactive silicone composition (I) for forming a first silicone-based adhesive layer, and a curable reactive silicone composition (II) for forming a second silicone-based adhesive layer, containing formula R ３ SiO １／２ Siloxane units (M units) represented by the formula: SiO ４／２ A method for designing a peelable laminate containing a multilayer silicone adhesive layer according to any one of claims 1 to 7, characterized in that the content of the silicone resin containing siloxane units (Q units) represented by is selected to be higher than the content of the silicone resin in the composition (I), and the amount of curing reactive silicone composition (II) applied is selected such that the thickness of the first silicone adhesive layer is thinner than that of the second silicone adhesive layer.

14. Furthermore, the release layer is selected to be a fluorine-free release layer, and the curing reactive silicone composition (I) and curing reactive silicone composition (II) are selected to be curing reactive silicone compositions that include a hydrosilylation reaction. A method for designing a peelable laminate containing a multilayer silicone adhesive layer as described in claim 13.

15. Use of a curable reactive silicone composition for the purpose of producing a releaseable laminate containing a multilayer silicone adhesive layer according to any one of claims 1 to 7, wherein the curable reactive silicone composition is (a) R ３ SiO １／２ Siloxane units (M units) represented by the formula: SiO ４／２ A silicone resin containing siloxane units (Q units) represented by (b) an organopolysiloxane having at least two alkenyl atoms in one molecule, (c) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and (d) a catalyst for hydrosilylation reactions. including, and, In a curable reactive silicone composition (I) used to obtain a first silicone adhesive layer, the mass ratio of component (a) / component (b) is in the range of 0 to 0.25, and the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles per mole of total alkenyl groups in component (b). In a curable reactive silicone composition (II) used to obtain a second silicone adhesive layer, the mass ratio of component (a) to component (b) is in the range of 0.25 to 5.0, the number of silicon-bonded hydrogen atoms in component (c) is in the range of 0.5 to 50 moles per mole of total alkenyl groups in component (b), and the composition contains 30% by mass or more of component (a) when the solid content of the composition is 100% by mass. The use of a curing reactive silicone composition characterized by the above.

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