Adhesive structure and method for manufacturing the adhesive structure

Abstract

The present invention provides an adhesive structure that can suppress the aging degradation phenomenon of adhesive performance (specifically, the decrease in adhesive strength of structural adhesives over time). [Solution] The adhesive structure comprises, in order, a first adherend, a first plasma polymer layer, an adhesive layer, a second plasma polymer layer, and a second adherend, wherein the components constituting the first plasma polymer layer and the second plasma polymer layer each mainly contain organopolysiloxane, and the thicknesses of the first plasma polymer layer and the second plasma polymer layer are in the range of 10 to 100 nm.

Description

Technical Field

[0001] The present invention relates to an adhesive structure, a method for manufacturing the adhesive structure, and particularly, an adhesive structure having an adhesive layer formed on an adherend and a method for manufacturing the adhesive structure.

Background Art

[0002] For the purpose of improving the performance of automotive vehicles (handling stability, NVH performance, collision safety, fatigue durability, rust prevention) and reducing vehicle weight, structural adhesives are used in the joining of structural members that require strength and durability (for example, the joining of structural members in a vehicle body and a battery case).

[0003] As such a structural adhesive, for example, Patent Document 1 discloses an epoxy-based structural adhesive for joining metal members and the like in the field of automobiles and the like.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in structural adhesives such as the epoxy-based structural adhesive, acrylic adhesive, and urethane adhesive disclosed in Patent Document 1, there may occur an aging deterioration phenomenon of adhesive performance (particularly, a decrease in the adhesive strength of the structural adhesive over time). Furthermore, due to this aging deterioration phenomenon of adhesive performance, there is a risk that the vehicle performance may deteriorate.

[0006] As a measure to suppress the aging degradation phenomenon of structural adhesives, some automobiles have focused on the fact that this aging degradation phenomenon occurs due to a decrease in adhesive strength at the adhesive interface between the structural adhesive and the adherend, and have implemented a method of applying an organic film between the structural adhesive and the adherend to prevent this decrease in adhesive strength.

[0007] However, with existing methods of suppressing degradation using organic coatings, it is necessary to introduce a treatment bath into the manufacturing process to immerse the adherend in a surface treatment solution in order to form the organic coating on the adherend. In particular, when forming an organic coating on an adherend after press processing, a larger processing facility is required compared to forming an organic coating on an adherend before press processing, resulting in significant introduction costs. On the other hand, when forming an organic coating on an adherend before press processing, the organic coating cannot withstand high temperatures, making it impossible to perform hot stamping (press processing at high temperatures) on the adherend, thus limiting the material and shape of the adherend. Thus, even adhesive structures with organic coatings have shortcomings as a measure to suppress the degradation of adhesive performance over time, and it is necessary to adopt suppression measures different from existing technologies.

[0008] The object of the present invention is to provide an adhesive structure that can suppress the aging degradation phenomenon of adhesive performance (in particular, the decrease in adhesive strength of structural adhesives over time) by an inhibitory measure different from existing inhibitory measures using organic films, without having the above-mentioned drawbacks of existing inhibitory measures using organic films. [Means for solving the problem]

[0009] The inventors of this invention conducted diligent studies to achieve the above objectives, and as a result, discovered that the above problems can be solved by providing a plasma polymer layer having a specific component as its main component between the adherend and the adhesive layer, and further setting the thickness of the plasma polymer layer within a specific range, thereby completing the present invention.

[0010] To achieve the above objective, the adhesive structure of the invention described in claim 1 comprises, in order, a first adherend, a first plasma polymer layer, an adhesive layer, a second plasma polymer layer, and a second adherend. The components constituting the first plasma polymer layer and the second plasma polymer layer each contain organopolysiloxane as the main component, The first plasma polymer layer and the second plasma polymer layer are characterized in that their thicknesses are in the range of 10 to 100 nm, respectively.

[0011] According to this invention, it is possible to suppress the deterioration of adhesive performance over time (in particular, the decrease in adhesive strength of structural adhesives over time).

[0012] The invention described in claim 2 is characterized in that, in the invention described in claim 1, a covalent bond is formed at each of the interfaces between the first adherend and the first plasma polymer layer, the interface between the first plasma polymer layer and the adhesive layer, the interface between the adhesive layer and the second plasma polymer layer, and the interface between the second plasma polymer layer and the second adherend.

[0013] According to this invention, since covalent bonds exist at the interface between the adherend and the plasma polymer layer, and at the interface between the plasma polymer layer and the adhesive layer, water molecules are not adsorbed and the bonding strength does not decrease, thus suppressing the deterioration of adhesive performance over time (in particular, the decrease in adhesive strength of structural adhesives over time under the usage environment).

[0014] The invention described in claim 3 is the invention described in claim 2, wherein the first adherend and the second adherend are made of metal. At the interface between the first adherend and the first plasma polymer layer, the metal atoms of the first adherend and the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the first plasma polymer layer are covalently bonded. At the interface between the first plasma polymer layer and the adhesive layer, substituents bonded to silicon atoms of siloxane bonds in the organopolysiloxane contained in the first plasma polymer layer are covalently bonded to molecular chains of components constituting the adhesive layer. At the interface between the adhesive layer and the second plasma polymer layer, the molecular chains of the components constituting the adhesive layer and the substituents bonded to the silicon atoms of the siloxane bonds in the organopolysiloxane contained in the second plasma polymer layer are covalently bonded. The interface between the second plasma polymer layer and the second adherend is characterized in that the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the second plasma polymer layer are covalently bonded to the metal atoms of the second adherend.

[0015] According to this invention, since covalent bonds exist at the interface between the adherend and the plasma polymer layer, and at the interface between the plasma polymer layer and the adhesive layer, in addition to suppressing the deterioration of adhesive performance over time (particularly the decrease in adhesive strength of structural adhesives over time), water molecules are not adsorbed and the bonding strength does not decrease, thus suppressing the decrease in adhesive strength under usage conditions.

[0016] The invention described in claim 4 is characterized in that, in the invention described in any one of claims 1 to 3, the organopolysiloxane includes structural units derived from a precursor.

[0017] According to this invention, it is possible to further suppress the deterioration of adhesive performance over time (in particular, the decrease in adhesive strength of structural adhesives over time).

[0018] The method for manufacturing an adhesive structure according to claim 5 is the method for manufacturing an adhesive structure according to claim 1, A step of forming a first plasma polymer layer on a first adherend using a plasma polymer coating apparatus, A process of forming a second plasma polymer layer on a second substrate using a plasma polymer coating apparatus. A step of applying an adhesive to the first plasma polymer layer and / or the second plasma polymer layer, A step of joining the first adherend having the first plasma polymer layer formed thereon and the second adherend having the second plasma polymer layer formed thereon via the adhesive, and A step of curing the adhesive to obtain an adhesive layer characterized by including.

[0019] According to this invention, since an adhesive structure is manufactured by a plasma polymer coating apparatus, it is not necessary to spend a great deal of cost as compared with the cost of introducing a treatment bath for forming an organic film into the manufacturing process, and an adhesive structure can be manufactured without being affected by the processing conditions of press working (particularly, processing conditions at a high temperature state).

Effects of the Invention

[0020] According to the present invention, it is possible to suppress the phenomenon of secular deterioration of adhesive performance (particularly, the decrease in adhesive strength of a structural adhesive with the passage of time). Further, according to the present invention, since the adhesive structure of the present invention can be obtained by a plasma polymer coating apparatus, the cost of introducing the plasma polymer coating apparatus into the manufacturing process does not need to be a great deal of cost as compared with the cost of introducing a treatment bath for forming an organic film into the manufacturing process. According to the present invention, since the plasma polymer coating apparatus can be introduced in a post-process of the press working process of the adherend to obtain the adhesive structure of the present invention, it is not affected by the processing conditions of press working (particularly, processing conditions at a high temperature state).

Brief Description of the Drawings

[0021] [Figure 1] It is a diagram showing the configuration of the adhesive structure of the present invention. [Figure 2] It is a diagram showing the results regarding the influence of the thickness of the plasma polymer layer on the initial adhesive strength and the strength retention rate after wetting deterioration. [Figure 3] It is a diagram showing a state where fracture occurred within the plasma polymer layer when the thickness of the plasma polymer layer exceeded 100 nm. [Figure 4] This figure shows the results regarding the rate of change in strength of adhesive structures under constant temperature and humidity conditions. [Modes for carrying out the invention]

[0022] <Composition of adhesive structure> The adhesive structure of the present invention comprises, in order, a first adherend, a first plasma polymer layer, an adhesive layer, a second plasma polymer layer, and a second adherend, or is an adhesive structure consisting of these layers. The relationship between the adherend, the plasma polymer layer, and the adhesive layer is shown in Figure 1.

[0023] [Adherend] Examples of the first and second adherends include metal adherends (e.g., steel adherends and aluminum adherends). Examples of steel adherends include unplated steel adherends, galvanized steel adherends, and Al-Si plated steel adherends. Examples of aluminum adherends include wrought materials, extruded materials, and die-cast materials. The first and second adherends may be made of the same material or different materials. The thicknesses of the first and second adherends are the thicknesses typically assumed in the art (e.g., the automotive art).

[0024] [Plasma polymer layer] The components constituting the first plasma polymer layer and the second plasma polymer layer mainly consist of organopolysiloxane or consist of organopolysiloxane. Specifically, the first plasma polymer layer and the second plasma polymer layer are polymer coatings mainly consisting of a network of organopolysiloxane formed by depositing a precursor, which has been fragmented by being introduced into a plasma region, onto a substrate.

[0025] It is preferable that the structural units of the organopolysiloxane include (preferably mainly include) structural units derived from the precursor, or consist of structural units of the precursor.

[0026] As a precursor, it is preferable to have a precursor containing a functional group that is reactive with the reactive group of the adhesive used in the adhesive layer. For example, when epoxy adhesives are used, the precursor preferably contains an amino group and / or an epoxy group; when urethane adhesives are used, it preferably contains an isocyanate group and / or a hydroxyl group; and when acrylic adhesives are used, it preferably contains an amino group and / or a thiol group.

[0027] When considering epoxy adhesives, a precursor such as 3-(trimethoxysilyl)propylglycidyl ether can be used. In this case, the organopolysiloxane formed has an epoxy group as a substituent (symbol R in Figure 1) bonded to the silicon atom of the siloxane bond in the organopolysiloxane.

[0028] The components constituting the first plasma polymer layer and the second plasma polymer layer may consist of either a component primarily composed of organopolysiloxane, or a component consisting solely of organopolysiloxane. Alternatively, one of the layers may consist of a component primarily composed of organopolysiloxane, while the other layer consists solely of organopolysiloxane.

[0029] The thickness of the first plasma polymer layer and the second plasma polymer layer has a lower limit of 10 nm or more, preferably 20 nm or more, and more preferably 30 nm or more, and an upper limit of 100 nm or less, preferably 90 nm or less, and more preferably 80 nm or less. These lower and upper limits can be combined in any way.

[0030] If the plasma polymer layer thickness is less than 10 nm, sufficient corrosion resistance cannot be obtained in the adhesive layer, and the effect of suppressing aging degradation in the adhesive layer cannot be obtained. If the plasma polymer layer thickness exceeds 100 nm, the plasma polymer layer is brittle, and if it is excessively thick, fracture will occur within the plasma polymer layer, and the expected adhesive performance of the structural adhesive cannot be achieved.

[0031] The thickness of the plasma polymer layer can be measured using a known transmission electron microscope.

[0032] The first plasma polymer layer and the second plasma polymer layer can each consist of one or more layers.

[0033] Since the substrate surface has a plasma polymer layer, corrosion resistance can be improved and the decrease in adhesive strength under usage conditions can be suppressed. If a plasma polymer layer is not provided between the substrate and the adhesive layer, water molecules and corrosive factors (such as Cl) may penetrate the adhesive interface between the substrate (especially metal substrates) and the adhesive layer under usage conditions, potentially causing deterioration of the substrate surface (oxidation film growth and formation of corrosion products) and leading to a decrease in adhesive strength (aging deterioration).

[0034] [Adhesive layer] Examples of adhesive components that make up the adhesive layer include one-component thermosetting, one-component moisture-curing, and two-component room-temperature curing epoxy, urethane, and acrylic adhesives.

[0035] Examples of one-component thermosetting epoxy adhesives include a mixture of bisphenol A type epoxy and dicyandiamide. Examples of two-component room-temperature curing epoxy adhesives include a mixture of bisphenol A type epoxy resin and polyamidoamine.

[0036] A two-component, room-temperature curing urethane adhesive is a mixture of polyoxypropylene triol and diphenylmethane diisocyanate.

[0037] Cyanoacrylate is an example of a one-component moisture-curing acrylic adhesive. A two-component room-temperature curing acrylic adhesive is a mixture of a mixture containing a polymerization inhibitor and an oxidizing agent mainly composed of methyl methacrylate, and a mixture containing a reducing agent mainly composed of methyl methacrylate.

[0038] The adhesive layer may consist of one or more layers. The thickness of the adhesive layer is the thickness typically expected in this art (e.g., the automotive art field).

[0039] [Interface between the adherend and the plasma polymer layer, and interface between the plasma polymer layer and the adhesive layer] (Interface between the adherend and the plasma polymer layer) At the interface between the adherend and the plasma polymer layer, for example, if the adherend is a metal adherend, a covalent bond can be established between the metal atoms of the metal adherend (symbol M in Figure 1) and the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the plasma polymer layer, as shown in Figure 1.

[0040] Specifically, at the interface between the first adherend and the first plasma polymer layer, the metal atoms of the first adherend can be covalently bonded to the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the first plasma polymer layer, and at the interface between the second plasma polymer layer and the second adherend, the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the second plasma polymer layer can be covalently bonded to the metal atoms of the second adherend.

[0041] Furthermore, covalent bonds can be established between oxygen atoms (symbol O in Figure 1) in the oxide film present on the surface of the metal substrate and silicon atoms contained in the plasma polymer layer.

[0042] (Interface between the plasma polymer layer and the adhesive layer) At the interface between the plasma polymer layer and the adhesive layer, for example, as shown in Figure 1, a covalent bond can be established between a substituent (symbol R in Figure 1) bonded to the silicon atom of the siloxane bond in the organopolysiloxane contained in the plasma polymer layer and the molecular chain (symbol A in Figure 1) of the component constituting the adhesive layer.

[0043] Specifically, at the interface between the first plasma polymer layer and the adhesive layer, substituents bonded to the silicon atoms of the siloxane bonds in the organopolysiloxane contained in the first plasma polymer layer can be covalently bonded to the molecular chains of the components constituting the adhesive layer, and at the interface between the adhesive layer and the second plasma polymer layer, molecular chains of the components constituting the adhesive layer can be covalently bonded to the substituents bonded to the silicon atoms of the siloxane bonds in the organopolysiloxane contained in the second plasma polymer layer.

[0044] When the adherend and the adhesive layer are bonded by hydrogen bonds, water molecules may be adsorbed under the usage environment, reducing the bonding strength of the hydrogen bonds and potentially leading to a decrease in adhesive strength (deterioration over time). On the other hand, in the case of the adhesive structure of the present invention, unlike hydrogen bonds whose bonding strength is reduced by water molecules, covalent bonds exist at the interface between the adherend and the plasma polymer layer and at the interface between the plasma polymer layer and the adhesive layer. Therefore, water molecules are not adsorbed, preventing a decrease in bonding strength, and thus suppressing a decrease in adhesive strength under the usage environment.

[0045] <Method for manufacturing adhesive structures> The adhesive structure of the present invention can be obtained by a manufacturing method comprising the steps of: forming a first plasma polymer layer on a first adherend; forming a second plasma polymer layer on a second adherend; applying an adhesive to the first plasma polymer layer and / or the second plasma polymer layer; joining the first adherend on which the first plasma polymer layer is formed and the second adherend on which the second plasma polymer layer is formed via the adhesive; and curing the adhesive to obtain an adhesive layer.

[0046] (Steps to form a first plasma polymer layer on a first adherend, and steps to form a second plasma polymer layer on a second adherend) The steps of forming a first plasma polymer layer on a first adherend and forming a second plasma polymer layer on a second adherend in atmospheric pressure plasma can be carried out, for example, using a known plasma polymer coating apparatus, within the scope of common technical knowledge of those skilled in the art, with reference to International Publication No. 2018 / 141802.

[0047] (Step of applying an adhesive to the first plasma polymer layer and / or the second plasma polymer layer) The application of an adhesive to the first plasma polymer layer and / or the second plasma polymer layer can be carried out using a known adhesive coating machine.

[0048] It is preferable to set the range of the adhesive layer and / or the plasma polymer layer so that the plasma polymer layer is covered by the adhesive layer. By covering the plasma polymer layer with the adhesive layer, it is possible to prevent the plasma polymer layer from interfering with the chemical conversion treatment and / or electrodeposition coating of the adherend.

[0049] (A process of joining a first adherend on which a first plasma polymer layer is formed and a second adherend on which the second plasma polymer layer is formed via an adhesive.) The bonding of a first adherend on which a first plasma polymer layer is formed and a second adherend on which a second plasma polymer layer is formed can be achieved via an adhesive, for example, by fixing and / or assembling them by welding or mechanical fastening.

[0050] (A process of curing the adhesive to obtain an adhesive layer) The adhesive can be cured by natural drying or heat drying. For example, if the adhesive component constituting the adhesive layer is a thermosetting adhesive, the vehicle body containing the adherend, the plasma polymer layer, and the adhesive can be placed in a paint drying oven to cure the adhesive.

[0051] (Other processes) Before forming the first and second plasma polymer layers on the adherend, a step may be included in which the surface of the adherend is cleaned by degreasing and / or plasma treatment. This step maximizes the effect of suppressing the aging degradation of the plasma polymer layer.

[0052] The method for manufacturing the adhesive structure of the present invention can be carried out in a pre- and / or post-pressing process of the adherend.

[0053] The adhesive structure of the present invention can suppress the deterioration of adhesive performance over time in, for example, a vehicle body and a battery case. [Examples]

[0054] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0055] [Fabrication of adhesive structures] An adhesive structure consisting of a first adherend, a first plasma polymer layer, an adhesive layer, a second plasma polymer layer, and a second adherend was fabricated by the following method.

[0056] First, a first plasma polymer layer was formed on one surface of a cold-rolled automotive steel sheet (material: cold-rolled steel sheet SPCC; length 100 mm x width 25 mm x thickness 1.6 mm) as the first adherend, using a plasma polymer coating apparatus (Plasmatreat GmbH, PTU1616 (trade name)) by atmospheric pressure plasma treatment. Specifically, this first plasma polymer layer was formed by spraying and mixing 3-(trimethoxysilyl)propyl glycidyl ether as a monomer liquid for organopolysiloxane into a carrier gas (atmosphere), introducing the mixture into the tip of a coating gun, fragmenting the organopolysiloxane monomer with plasma, and then laminating the fragmented monomer onto the cold-rolled automotive steel sheet.

[0057] The thickness of the first plasma polymer layer was selected from the range of plasma polymer layer thicknesses shown in Figure 2 below. The formation of the first plasma polymer layer was carried out with reference to International Publication No. 2018 / 141802.

[0058] Next, a second plasma polymer layer was formed on one surface of a second adherend, a cold-rolled steel sheet for automobiles (material: cold-rolled steel sheet SPCC; length 100 mm × width 25 mm × thickness 1.6 mm), using the same method as for forming the first plasma polymer layer on the first adherend. The thickness of the second plasma polymer layer was made approximately the same as the thickness of the first plasma polymer layer.

[0059] Next, an adhesive layer was applied to the surface of the first plasma polymer layer opposite to the first adherend. The adhesive layer used was a one-component epoxy-based thermosetting adhesive (specifically, a mixture of bisphenol A epoxy and dicyandiamide). The thickness of the adhesive layer was 0.2 mm.

[0060] Furthermore, the adhesive layer on the first adherend and the first plasma polymer layer was bonded to the second plasma polymer layer on the second adherend. After this, the bonded structure was placed in a paint drying oven to cure the adhesive and obtain an adhesive structure.

[0061] [Effect of plasma polymer layer (coating) thickness on initial adhesive strength and strength retention rate after wet degradation] The tensile shear strength (adhesive strength) of the adhesive structure obtained in the above [Fabrication of Adhesive Structure] was measured in accordance with JIS K6850. As tensile shear strength (adhesive strength), the initial adhesive strength and the strength retention rate after wet degradation were measured. The strength retention rate after wet degradation is the tensile shear strength (adhesive strength) of the adhesive structure after being left for 1,000 hours at 80°C and 95% relative humidity.

[0062] The thickness of the plasma polymer layer (coating) was measured using a transmission electron microscope (Talos F200X (product name)), manufactured by FE-I Japan.

[0063] Figure 2 shows the results regarding the effect of plasma polymer layer thickness on initial adhesive strength and strength retention rate after wet degradation. In Figure 2, the circles and error bars represent the initial adhesive strength (left vertical axis) against the plasma polymer layer thickness (horizontal axis), and the diamond symbols and error bars represent the strength retention rate after wet degradation (right vertical axis) against a given plasma polymer layer thickness (horizontal axis). Note that the plasma polymer layer thickness on the horizontal axis does not represent the sum of the thickness of the first plasma polymer layer and the second plasma polymer layer. For example, if the plasma polymer layer thickness on the horizontal axis is 20 nm, it means that the thickness of the first plasma polymer layer is 20 nm and the thickness of the second plasma polymer layer is also 20 nm.

[0064] When the thickness of the plasma polymer layer was in the range of 10 nm to 100 nm, good results were obtained for both the initial adhesive strength and the strength retention rate after wet degradation.

[0065] On the other hand, when the thickness of the plasma polymer layer exceeded 100 nm, fracture occurred within the formed film, resulting in a decrease in initial strength. Figure 3 shows the state of this fracture. This fracture is thought to be caused by the film becoming excessively thick.

[0066] Furthermore, when the thickness of the plasma polymer layer was less than 10 nm, the strength retention rate after wet degradation decreased (i.e., the effect of suppressing aging degradation was not obtained).

[0067] [Rate of change in strength of adhesive structures under constant temperature and humidity conditions] The strength change rate of the adhesive structures obtained in the above [Fabrication of Adhesive Structures] (Example) and the adhesive structure obtained in the Example without the first and second plasma polymer layers (Comparative Example) was compared under constant temperature and humidity degradation conditions (under degradation test conditions simulating the usage environment). The degradation conditions were 80°C and 95% relative humidity. The thickness of the first plasma polymer layer and the second plasma polymer layer in the adhesive structure were approximately 20 nm for the experiment.

[0068] The tensile shear strength (adhesive strength) of the adhesive structures of the examples and comparative examples was measured in accordance with JIS K6850 after a predetermined degradation test period.

[0069] Figure 4 shows the results regarding the rate of change in strength of adhesive structures under constant temperature and humidity conditions. In Figure 4, the horizontal axis represents the degradation test time (in hours), and the vertical axis represents the strength retention rate [%]. The strength retention rate [%] was calculated as: bond strength after degradation test [MPa] / initial bond strength [MPa] × 100.

[0070] The adhesive structure in the example exhibits a suppressed decrease in strength retention (strength reduction) as the degradation test time increases, compared to the adhesive structure in the comparative example. For example, the degradation test time until the strength retention rate decreased from 100% to 70% was approximately 200 hours for the adhesive structure in the comparative example, but approximately 700 hours for the adhesive structure in the example. In other words, the degradation test time (durability time) of the adhesive structure in the example was approximately three times longer.

Claims

1. It comprises, in order, a first adherend, a first plasma polymer layer, an adhesive layer, a second plasma polymer layer, and a second adherend. The components constituting the first plasma polymer layer and the second plasma polymer layer each contain organopolysiloxane as the main component, An adhesive structure characterized in that the thickness of the first plasma polymer layer and the second plasma polymer layer are in the range of 10 to 100 nm, respectively.

2. The adhesive structure according to claim 1, characterized in that it has covalent bonds at each of the interfaces between the first adherend and the first plasma polymer layer, the interface between the first plasma polymer layer and the adhesive layer, the interface between the adhesive layer and the second plasma polymer layer, and the interface between the second plasma polymer layer and the second adherend.

3. The first adherend and the second adherend are made of metal. At the interface between the first adherend and the first plasma polymer layer, the metal atoms of the first adherend and the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the first plasma polymer layer are covalently bonded. At the interface between the first plasma polymer layer and the adhesive layer, substituents bonded to silicon atoms of siloxane bonds in the organopolysiloxane contained in the first plasma polymer layer are covalently bonded to molecular chains of components constituting the adhesive layer. At the interface between the adhesive layer and the second plasma polymer layer, the molecular chains of the components constituting the adhesive layer and the substituents bonded to the silicon atoms of the siloxane bonds in the organopolysiloxane contained in the second plasma polymer layer are covalently bonded. The adhesive structure according to claim 2, characterized in that at the interface between the second plasma polymer layer and the second adherend, the oxygen atoms of the siloxane bonds in the organopolysiloxane contained in the second plasma polymer layer are covalently bonded to the metal atoms of the second adherend.

4. The adhesive structure according to any one of claims 1 to 3, characterized in that the structural units of the organopolysiloxane include structural units derived from a precursor.

5. A method for manufacturing an adhesive structure according to claim 1, A process of forming a first plasma polymer layer on a first adherend using a plasma polymer coating apparatus, A process of forming a second plasma polymer layer on a second adherend using a plasma polymer coating apparatus. A step of applying an adhesive to the first plasma polymer layer and / or the second plasma polymer layer, A step of joining the first adherend on which the first plasma polymer layer is formed and the second adherend on which the second plasma polymer layer is formed via the adhesive, and The process of curing the adhesive to obtain an adhesive layer. A method for manufacturing an adhesive structure, characterized by including the following:

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