Laminate of resin body and gel body and method for manufacturing the same

Abstract

To provide a laminated body that has high adhesiveness between a resin body containing a fluorine-based resin and a silicone gel and that can be attached to and detached from an adherend for use.SOLUTION: A laminated body comprises: a resin body; and a gel body, wherein the resin body comprises a fluorine-based resin, and the gel body comprises a silicone gel and lipophilic silica particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate of a resin body and a gel body and a method for producing the same. [Background technology]

[0002] Advances in computer miniaturization technology have led to the incorporation of sensors, actuators, microcontrollers, and other components into IoT (Internet of Things) devices. IoT devices are found in, for example, home appliances such as speakers, lighting, and air conditioners, buildings such as tunnels, bridges, and skyscrapers, and wearable devices attached to helmets and living bodies, allowing for constant monitoring of the status of equipment and the human body.

[0003] In recent years, IoT devices have been required to send and receive larger volumes of data at higher speeds, and increasing the transmission capacity using high-frequency bands has attracted attention, with particular attention being paid to the use of high-frequency bands above 30 GHz, known as millimeter waves. However, while the use of high-frequency bands allows for a very large transmission capacity, transmission losses along the transmission path are likely to be large. Large transmission losses can lead to inconveniences such as loss of electrical signals and longer signal delay times.

[0004] For applications using high frequency bands, it is conceivable to use fluororesin, which has a low relative permittivity and a low dielectric loss tangent, in order to reduce transmission loss. Fluororesin is being used as the resin base material for printed wiring boards in IoT devices, and efforts are being made to accommodate high frequency bands as well.

[0005] For example, Patent Document 1 discloses a fluororesin substrate used in a biological information measuring device that outputs information about a living body or an artificial organ that constitutes a living body, and discloses that the fluororesin substrate has a fluororesin as its main component and has a modified layer on at least a partial region of its outer surface, and that the modified layer contains a siloxane bond and a hydrophilic organic functional group and has good adhesion to human cells.

[0006] Patent Document 2 discloses an electronic device comprising a housing and electronic components arranged inside the housing, and discloses that the electronic device is used by being attached to a person or an object, and the housing comprises a lower surface portion having a contact surface that comes into contact with the adherend, an upper surface portion that is separated vertically from the lower surface portion across a first space, and side surfaces that are arranged around the first space and connected to the upper surface portion and the lower surface portion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-122448 [Patent Document 2] Japanese Patent Application Publication No. 2020-161569 Summary of the Invention [Problem to be solved by the invention]

[0008] In recent years, it has become conceivable to not only install IoT devices at specific locations on adherends, but also to adhere and detach (attach and detach) IoT devices to adherends such as people and objects, and change the installation location of the IoT device depending on the purpose. However, while Patent Document 1 mentions adhering a fluororesin substrate, it does not anticipate detachment or attachment and detachment.

[0009] Although Patent Document 2 does not disclose detachment or attachment, it does disclose Teflon (registered trademark) as one of the materials for the upper surface, and silicone gel, urethane gel, and acrylic gel as materials for the lower surface that are attached to the adherend, so that such a housing (laminate) can be attached to the adherend. However, when a fluorine-based resin such as Teflon (polytetrafluoroethylene) is adhered to any of the gels, silicone gel, urethane gel, and acrylic gel, the adhesive strength is insufficient, and there is a risk that the laminate will separate or break when detached from the adherend.

[0010] An object of the present invention is to provide a laminate that has high adhesiveness between a resin body containing a fluorine-based resin and a silicone gel, and that can be attached to and detached from an adherend for use. [Means for solving the problem]

[0011] In view of the above problems, the inventors of the present invention have conducted extensive research and have found that the adhesive strength between a resin body and a gel body can be increased by adding lipophilic silica particles to a gel body, setting the oxygen concentration near the surface of the heat-cured gel body to 1% by volume or more, and then subjecting the surface of the gel body to plasma treatment, or by laminating an uncured gel body and a surface-modified resin body together and then heat-curing the gel body to form a gel body, thereby completing the present invention.

[0012] That is, the present invention comprises the following configurations. [1] A laminate of a resin body and a gel body, characterized in that the resin body contains a fluorine-based resin, and the gel body contains silicone gel and lipophilic silica particles. [2] The laminate according to [1], wherein the adhesive strength between the resin body and the gel body is 0.4 N / mm or more. [3] The laminate according to [1] or [2], wherein the surfaces of the lipophilic silica particles are silica particles whose surfaces have been surface-modified with at least one of dialkylsilane, trialkylsilane, polysiloxane, aminosilane, and polysilazane. [4] The laminate according to any one of [1] to [3], wherein the fluorine-based resin is a copolymer of at least one of hexafluoropropylene units, perfluoroalkyl vinyl ether units, methylene units, ethylene units, and perfluorodioxole units with difluoromethylene units, or polytetrafluoroethylene. [5] The laminate according to any one of [1] to [4], wherein the surface of the resin body is plasma-treated. [6] A method for producing a laminate of a resin body and a gel body, comprising the steps of: setting the oxygen concentration near the surface of the resin body to less than 0.5% by volume, performing plasma treatment on the surface of the resin body, and producing a surface-modified resin body; and either of the following steps (I) or (II), wherein the resin body contains a fluorine-based resin, and the gel body contains silicone gel and lipophilic silica particles. (I) A step of setting the oxygen concentration near the surface of the heat-cured gel body to 1% by volume or more, performing plasma treatment on the surface of the gel body to produce a surface-modified gel body, and then laminating the surface-modified gel body and the surface-modified resin body. (II) A step of laminating a gel-like material and the surface-modified resin body, and then heat-curing the gel-like material to form the gel body. [Effects of the Invention]

[0013] By adding lipophilic silica particles to the gel body, setting the oxygen concentration near the surface of the heat-cured gel body to 1% by volume or more, and then subjecting the surface of the gel body to plasma treatment, or by laminating an uncured gel body and a surface-modified resin body and then heat-curing the gel body to form a gel body, a laminate can be obtained that has high adhesion between the fluororesin-containing resin body and the silicone gel and can be attached and detached to an adherend for use. Because the laminate of the present invention is not damaged when detached from the adherend, it can be freely attached and detached to the adherend, and its installation location can be freely changed depending on the purpose. Furthermore, because the installation location can be freely changed, it can be used not only as a high-frequency IoT device, but also as a removable fluororesin sheet or mat to temporarily prevent chemical splashes or temporarily improve slip resistance. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B are conceptual diagrams of an atmospheric pressure plasma processing apparatus, in which (a) is an overall side view and (b) is a plan view showing the relationship between a rod-shaped electrode and a substrate. [Figure 2]FIG. 2 is a conceptual diagram of a plasma irradiation head in the plasma jet processing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0015] The laminate of the present invention is a laminate of a resin body and a gel body (hereinafter, sometimes simply referred to as "laminate"), in which the resin body contains a fluorine-based resin and the gel body contains a silicone gel and lipophilic silica particles. In this specification, the fluorine-based resin refers to a resin containing fluorine atoms in its molecules.

[0016] <Resin body> The fluororesin is preferably a copolymer of at least one of a hexafluoropropylene unit, a perfluoroalkyl vinyl ether unit, a methylene unit, an ethylene unit, and a perfluorodioxole unit with at least one of a difluoromethylene unit and a tetrafluoroethylene unit, or polytetrafluoroethylene. Among these, the fluororesin more preferably contains a tetrafluoroethylene unit. In 100 mol% of the total resin in the resin body, the tetrafluoroethylene unit is more preferably 30 mol% or more, even more preferably 50 mol% or more, particularly preferably 70 mol% or more, and most preferably 90 mol% or more. The tetrafluoroethylene unit refers to a structural unit derived from tetrafluoroethylene, and the same applies to other monomer units.

[0017] Examples of fluorine-based resins include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-perfluorodioxole copolymer (TFE / PDD), and chlorotrifluoroethylene-ethylene copolymer (ECTFE). Among these, at least one of PTFE, PFA, ETFE, and FEP is preferred, with PTFE being particularly preferred, from the viewpoint of the number of carbon-fluorine bonds in the monomer unit (the substitution ratio of fluorine atoms). The fluorine-based resin may be one type or may contain two or more types. Of 100 parts by mass of all resins in the resin body used in the present invention, the fluororesin is contained in an amount of more than 50 parts by mass, preferably 80 parts by mass or more, more preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, particularly preferably 99 parts by mass or more, and most preferably 100 parts by mass (containing only the fluororesin).

[0018] The resin body used in the present invention may contain a resin other than the above-mentioned fluorine-based resin. Examples of resins other than fluorine-based resins include olefin-based resins such as polyethylene resin, polypropylene resin, and cycloolefin resin; polyester-based resins such as polyethylene terephthalate resin; polyimide-based resins; styrene-based resins such as styrene resin and syndiotactic polystyrene resin; aromatic polyether ketone-based resins such as aromatic polyether ketone resin, polyether ether ketone resin, and polyphenylene ether resin; polyacetal-based resins; polyphenylene sulfide-based resins; and bismaleimide triazine-based resins. In 100 parts by mass of the total resin in the resin body used in the present invention, the amount of resin other than fluorine-based resin is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and most preferably 0 part by mass (the resin body does not contain any resin other than fluorine-based resin).

[0019] The form of the resin body that can be used in the present invention is not particularly limited as long as it is a shape that can be subjected to plasma irradiation, as described below, and can be applied to bodies having various shapes and structures. Examples include, but are not limited to, rectangular, spherical, thin-film shapes, etc., with surface shapes such as flat, curved, and bent surfaces. Furthermore, the resin body may be molded by various molding methods such as injection molding, melt extrusion molding, paste extrusion molding, compression molding, cutting molding, cast molding, and impregnation molding, depending on the properties of the fluororesin. Furthermore, the resin body may have, for example, a dense continuous structure of resin like a typical injection-molded body, a porous structure, a nonwoven fabric, or other structures.

[0020] The thickness of the resin body is preferably 1 μm or more, and from the viewpoint of insulation properties and reduction of transmission loss, more preferably 5 μm or more, and even more preferably 10 μm or more. There is no particular upper limit on the thickness of the resin body, but when used as a flexible printed wiring board, a thinner resin body is preferable, for example, 5 mm or less.

[0021] In the present invention, it is not necessary to roughen the surface of the resin body with sandpaper or the like, and the surface roughness Ra of the resin body is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. The surface roughness Ra can be determined by measurement in accordance with JIS B 0601, and the surface roughness Ra of the laminates described in the examples below is all 0.3 μm or less.

[0022] <Gel body> The gel body includes a silicone gel. The silicone gel is not particularly limited, and examples thereof include an addition-curing liquid silicone gel and a heat-vulcanizing millable silicone gel that uses peroxide for vulcanization, but an addition-curing liquid silicone gel is preferred.

[0023] A smaller penetration of the gel body is preferable because it results in a harder and stronger gel body. However, even a gel body with a relatively high penetration (for example, a gel body with a penetration of about 30 to 50) can be made harder and stronger by increasing the thickness of the gel body or by incorporating a relatively large amount of lipophilic silica particles, which will be described later. As a result, the gel body can be prevented from breaking when attempting to detach the laminate from the adherend. The penetration of the gel body is preferably 50 or less, more preferably 40 or less, and even more preferably 30 or less. There are no particular restrictions on the lower limit of the penetration of the gel body, but it is, for example, 0 or more, preferably 1 or more, and more preferably 3 or more. The method for measuring the penetration will be described later.

[0024] The gel body further contains lipophilic silica particles. The gel body preferably contains 5 to 27 parts by mass of lipophilic silica particles per 100 parts by mass of silicone gel, more preferably 10 to 25 parts by mass, and even more preferably 15 to 25 parts by mass. By including 5 or more parts by mass of lipophilic silica particles, the loss factor tan δ is reduced, i.e., the contribution of viscosity is reduced, resulting in a hard and strong gel body. As a result, the gel body is prevented from breaking when attempting to detach the laminate from the adherend. On the other hand, if the lipophilic silica particles are included in an amount greater than 27 parts by mass, a large number of air bubbles may be generated during preparation of the gel body, potentially preventing the gel body from adhering to the resin body.

[0025] The thickness of the gel body is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 3 mm or more. By making the thickness of the gel body 1 mm or more, the gel body can be prevented from being easily broken. There is no particular upper limit to the thickness of the gel body, but from the viewpoint of cost and appearance, it is, for example, 30 mm or less.

[0026] The loss factor tanδ of the gel body is preferably 0.580 or less, and more preferably 0.560 or less. By making the loss factor tanδ 0.580 or less, the contribution of viscosity is small, making it possible to make the gel body hard and strong, and preventing the gel body from breaking. The method for measuring the loss factor tanδ will be described later.

[0027] <Oleophilic silica particles> Silica particles are hydrophilic because they have silanol groups, but can be made into lipophilic silica particles by chemically changing the silanol groups present on the surface of silica particles.In the following, silica particles before chemical change are referred to as hydrophilic silica particles.The compound used for the change is not particularly limited as long as it can chemically react with the -OH of the silanol groups in the hydrophilic silica particles to introduce lipophilic groups (hydrophobic groups), and is preferably at least one of the following: dialkylsilanes such as dimethyldichlorosilane, diethyldichlorosilane, dimethyldibromosilane, and diethyldibromosilane; trialkylsilanes such as trimethylchlorosilane, triethylchlorosilane, trimethylbromosilane, and triethylbromosilane; polysiloxanes such as dimethylpolysiloxane; aminosilanes such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; and polysilazanes such as perhydropolysilazane, methylpolysilazane, dimethylpolysilazane, phenylpolysilazane, and vinylpolysilazane. The surface of hydrophilic silica particles can be modified with the above-mentioned compounds to introduce lipophilic groups such as alkyl groups (particularly methyl groups) and amino groups (particularly NH2 groups) into silanol groups, thereby making the silica particles lipophilic.

[0028] <Adhesive strength> In the laminate of the present invention, the adhesive strength between the resin body and the gel body (hereinafter sometimes simply referred to as "adhesive strength") is preferably 0.4 N / mm or more, more preferably 0.6 N / mm or more, even more preferably 0.8 N / mm or more, and particularly preferably 1.0 N / mm or more. If the adhesive strength is less than 0.4 N / mm, there is a risk that the gel body will be destroyed or the resin body and the gel body will peel off when the laminate is detached from the adherend. The method for measuring adhesive strength will be described later.

[0029] <Method of manufacturing laminate> The method for producing the laminate of the present invention will be described below.

[0030] The method for producing a laminate includes a step of producing a surface-modified resin body by subjecting the surface of the resin body to plasma treatment while setting the oxygen concentration near the surface of the resin body to less than 0.5% by volume, and either of the following steps (I) or (II). (I) A step of setting the oxygen concentration near the surface of the heat-cured gel body to 1% by volume or more, performing plasma treatment on the surface of the gel body to produce a surface-modified gel body, and then laminating the surface-modified gel body and the surface-modified resin body. (II) A step of laminating a gel-like material and the surface-modified resin body, and then heat-curing the gel-like material to form the gel body.

[0031] 1. Plasma treatment of the surface of the resin body The surface of the resin body can be modified by plasma treatment, and it is preferable to perform the plasma treatment on the surface of the resin body at a surface temperature of (the melting point of the fluororesin -150°C) or higher. By achieving such a surface temperature, the mobility of the polymers of the polymer compound on the surface of the resin body to be irradiated with plasma is increased. When a polymer compound in such a highly mobile state is irradiated with plasma, when bonds between carbon atoms of the polymer compound and carbon atoms or other atoms are broken, the carbon atoms whose bonds have been broken within each polymer undergo a crosslinking reaction, thereby sufficiently forming peroxide radicals on the surface of the resin body. In particular, when the fluororesin constituting the resin body is PTFE, the surface temperature of the resin body is preferably 180°C or higher, and more preferably 200°C or higher. The upper limit of the surface temperature of the resin body is not particularly limited, but it may be, for example, (melting point +20)°C or lower. The surface of the resin body is subjected to plasma treatment in a state where oxygen is minimized near the surface of the resin body, thereby forming sufficient peroxide radicals on the surface of the resin body, thereby surface-modifying the resin body. Specifically, the oxygen concentration near the surface of the resin body (plasma-irradiated area) is set to less than 0.5% by volume, and the surface of the resin body is subjected to plasma treatment to produce a surface-modified resin body. Regarding the plasma treatment, for example, the surface of the resin body may be modified by treating it with atmospheric pressure plasma while the surface temperature of the resin body is elevated. By performing atmospheric pressure plasma treatment, the radicals, electrons, ions, etc. contained in the plasma induce the formation of dangling bonds by defluorination of the surface of the resin body. Note that atmospheric pressure does not necessarily have to be 1013 hPa strictly, but may be in the range of 700 to 1300 hPa. After that, by exposing the resin body to the atmosphere for several minutes to 10 minutes, the dangling bonds react with the water components in the atmosphere, and hydrophilic functional groups such as peroxide radicals, hydroxyl groups, and carbonyl groups are spontaneously formed in the dangling bonds.

[0032] In the present invention, it is preferable to modify the surface of a resin body using atmospheric pressure plasma. The conditions for this atmospheric pressure plasma treatment are preferably such that the surface temperature of the resin body is within the above-mentioned predetermined range and the output power density is within the below-mentioned predetermined range. Conditions that can generate atmospheric pressure plasma and are used in the technical field of surface modification of resin bodies using plasma can be appropriately adopted. However, in the present invention, atmospheric pressure plasma treatment is performed while keeping the surface temperature of the resin body within a predetermined temperature range that can increase the mobility of the fluororesin polymer on the surface of the resin body. Therefore, when the surface temperature is increased solely by the heating effect of the atmospheric pressure plasma treatment, it is preferable to perform the atmospheric pressure plasma treatment under conditions that achieve the heating effect.

[0033] To generate atmospheric pressure plasma, for example, a high frequency power supply with an applied voltage frequency of 50 Hz to 2.45 GHz is used. Although it is difficult to generalize because it depends on the plasma generator and the constituent material of the resin body, for example, an output power density (output power per unit area) of 15 W / cm 2The upper limit is not particularly limited, but for example, 40 W / cm 2 It may be the following: Furthermore, when a pulse output is used, the pulse modulation frequency should be 1 to 50 kHz (preferably 5 to 30 kHz) and the pulse duty should be 5 to 99% (preferably 15 to 80%, more preferably 25 to 70%). The opposing electrodes can be made of cylindrical or flat metal with at least one side coated with a dielectric. From the viewpoint of plasma generation and heating, the distance between the opposing electrodes depends on other conditions, but is preferably 5 mm or less, more preferably 3 mm or less, even more preferably 2 mm or less, and particularly preferably 1 mm or less. There is no particular lower limit to the distance between the opposing electrodes, but it is, for example, 0.5 mm or more.

[0034] The gas used to generate the plasma may be, for example, a rare gas such as helium, argon, or neon, or a reactive gas such as oxygen, nitrogen, or hydrogen. That is, it is preferable to use only non-polymerizable gases as the gas used in the present invention. Furthermore, these gases may be one or more rare gases alone, or a mixed gas of one or more rare gases and an appropriate amount of one or more reactive gases may be used. The plasma may be generated under the conditions in which the gas atmosphere is controlled using a chamber, or may be generated under completely open atmosphere conditions, for example, by flowing a rare gas through the electrode portion.

[0035] In the present invention, the surface of the resin body opposite to the plasma-irradiated surface is hardly affected by the plasma treatment (the effect of improving hardness, etc. is smaller than that of the plasma-irradiated surface), so the various properties that fluororesin originally possesses (e.g., chemical resistance, weather resistance, heat resistance, electrical insulation, etc.) are not impaired and are fully exhibited.

[0036] An example of an embodiment of atmospheric pressure plasma treatment applicable to the method for producing a resin body used in the present invention will be described below with reference to FIG. 1, mainly taking as an example a case where the resin body is in the form of a PTFE sheet (thickness: 0.2 mm). However, the present invention is not limited to this example in any way, and can of course be embodied in various forms within the scope of the gist of the present invention.

[0037] FIG. 1 is a conceptual diagram of a capacitively coupled atmospheric plasma processing apparatus, an example of an atmospheric plasma processing apparatus that can be used in the present invention. The atmospheric plasma processing apparatus A shown in FIG. 1(a) comprises a high-frequency power supply 10, a matching unit 11, a chamber 12, a vacuum pumping system 13, an electrode 14, an electrode elevating mechanism 15, a grounded cylindrical rotary stage and sample holder 16, and a rotary stage control unit (not shown). The rotary stage 16 is positioned opposite the electrode 14. The cylindrical rotary stage and sample holder 16 can be made of, for example, an aluminum alloy. The electrode 14 can be rod-shaped, as shown in FIG. 1(b), and can have an inner tube 18 made of, for example, copper, covered with an outer tube 19 made of, for example, aluminum oxide (Al2O3).

[0038] The surface modification method for a resin body using the atmospheric pressure plasma processing apparatus A shown in Figure 1 is as follows. First, the resin body is washed with an organic solvent such as acetone or with water such as ultrapure water, as necessary. Then, as shown in Figure 1(a), a sheet-shaped sample (a resin body containing a fluororesin) 20 is placed on a sample holder 16 in a chamber 12. Then, using a suction device (not shown), the air in the chamber 12 is sucked through a vacuum exhaust system 13 to reduce the pressure, and a gas that generates plasma is supplied into the chamber 12 (see the arrow in Figure 1(a)), thereby bringing the pressure inside the chamber 12 to atmospheric pressure. Note that the sample 20 is not shown in Figure 1(a) but is shown only in Figure 1(b), which will be described later.

[0039] With an apparatus such as that shown in FIG. 1(a), plasma treatment can be performed with the oxygen concentration in the vicinity of the surface of the resin body (plasma irradiated region) set to less than 0.5% by volume.

[0040] Next, the height of the electrode lifting mechanism 15 (vertical direction in FIG. 1(a)) is adjusted to move the electrode 14 to the desired position. By adjusting the height of the electrode lifting mechanism 15, the distance between the electrode 14 and the surface (top surface) of the sample 20 can be adjusted. The distance between the electrode 14 and the surface of the sample 20 is preferably 5 mm or less, and more preferably 2 mm or less. In particular, when the surface temperature of the resin body is to be set within a specific range by natural temperature rise due to plasma treatment, it is particularly preferable that the distance be 1.0 mm or less. Note that, since the sample 20 is moved by the rotation of the rotary stage 16, it goes without saying that the electrode 14 and the sample 20 must not come into contact with each other. Furthermore, by rotating the rotary stage 16, the desired portion of the resin body surface can be irradiated with plasma. For example, the rotation speed of the rotary stage 16 is preferably 1 to 3 mm / sec, but the present invention is not limited to this example. The plasma irradiation time for the sample 20 can be adjusted, for example, by varying the rotation speed of the rotary stage 16 or by repeatedly rotating the rotary stage 16 a desired number of times.

[0041] While moving the rotating stage 16 to move the sample 20, the high-frequency power supply 10 is activated to generate plasma between the electrode 14 and the rotating stage 16, irradiating the desired area on the surface of the sample 20. In this case, a high-frequency power supply 10 with the applied voltage frequency and output power density described above can be used, and alumina-coated copper electrodes and an aluminum alloy sample holder can be used to achieve glow discharge under dielectric barrier discharge conditions. This allows stable generation of peroxide radicals on the resin surface. The peroxide radicals are introduced by radicals, electrons, ions, etc. contained in the plasma, which induce the formation of dangling bonds by defluorination of the PTFE sheet surface. These bonds then react with water and other components in the air remaining in the chamber or by exposing the PTFE sheet to clean air after plasma treatment. In addition to peroxide radicals, hydrophilic functional groups such as hydroxyl and carbonyl groups can also spontaneously form on the dangling bonds.

[0042] The intensity of the plasma irradiated onto the surface of the resin body can be adjusted appropriately by adjusting the various parameters of the high-frequency power supply, the distance between the electrode 14 and the surface of the resin body, etc. The above-mentioned preferred conditions for generating atmospheric plasma (applied voltage frequency, output power density, pulse modulation frequency, pulse duty, etc.) are particularly effective when the resin body is in the form of a PTFE sheet. Also, by adjusting the cumulative irradiation time onto the surface of the resin body according to the output power density, it is possible to set the surface of the resin body to a specific temperature range. For example, when the frequency of the applied voltage is 5 to 30 MHz, the distance between the electrode 14 and the surface of the resin body is 0.5 to 2.0 mm, and the output power density is 15 to 30 W / cm 2 In this case, the cumulative irradiation time for the resin body surface is preferably 50 to 3300 seconds, more preferably 250 to 3300 seconds, and particularly preferably 550 to 2400 seconds. In particular, it is preferable that the surface temperature of a PTFE sheet-shaped resin body is 210 to 327°C and the irradiation time is 600 to 1200 seconds. If the irradiation time is too long, the effects of heating tend to appear. Note that the plasma irradiation time refers to the cumulative time during which the resin body surface is irradiated with plasma. It is sufficient that the surface temperature of the resin body is (melting point - 150)°C or higher for at least a portion of the plasma irradiation time. For example, it is sufficient that the surface temperature of the resin body is (melting point - 150)°C or higher for at least half (preferably at least two-thirds) of the plasma irradiation time. In either embodiment, by setting the surface temperature of the resin body within the above range, the mobility of the PTFE molecules on the surface of the resin body is improved, and the probability that a carbon atom in a carbon-fluorine bond of a PTFE molecule cut by plasma will bond with a carbon atom of another PTFE molecule created in the same manner to form a carbon-carbon bond is significantly improved, thereby improving the surface hardness.

[0043] Alternatively, a heating means for heating the sample 20 may be provided separately. As shown in FIG. 1(b), a heat ray irradiation device such as a halogen heater 17 may be disposed near the electrode 14 to directly heat the surface of the resin body. Alternatively, to raise the ambient temperature within the chamber 12, a heating device for heating the gas within the chamber 12 and a circulation device equipped with a stirring blade or the like for circulating the heated gas within the chamber 12 may be disposed within the chamber 12. Alternatively, a heating means may be disposed on the rotating stage 16 to heat the sample 20 from below, or a combination of these may be used. The heating temperature provided by the heating means may be appropriately set and controlled taking into consideration the characteristics of the fluororesin constituting the resin body, the shape of the molded body, the heating effect of the plasma treatment, and other factors. It is also preferable to preheat the molded body before operating the high-frequency power supply 10 so that the desired temperature is reached during plasma irradiation.

[0044] The surface temperature of the molded body during the plasma treatment can be measured using a radiation thermometer 21 as shown in FIG. 1(b) or a temperature measurement sticker.

[0045] 2. Plasma treatment of the surface of the gel body While surface modification of the gel body may be considered to improve adhesion between the gel body and the resin body, atmospheric pressure plasma treatment using the apparatus shown in Figure 1, as with the resin body, failed to improve adhesion between the gel body and the resin body. However, it was found that plasma treatment with an oxygen concentration of 1% by volume or more near the surface of the gel body (plasma irradiation area) to produce a surface-modified gel body can improve adhesion between the gel body and the resin body. While the method for atmospheric pressure plasma treatment of the gel body surface is not particularly limited, plasma jet treatment is preferred. Note that Sections 2 and 3 below will explain the step of plasma treating the gel body surface (step (I) above), while a method for improving adhesion between the gel body and the resin body without plasma treatment of the gel body surface (step (II) above) will be explained in Section 4 below.

[0046] The oxygen concentration near the surface of the gel body is preferably 3% by volume or more, more preferably 5% by volume or more, even more preferably 7% by volume or more, and particularly preferably 10% by volume or more.

[0047] An example of an embodiment of the plasma jet treatment applicable to the gel body used in the present invention will be described below with reference to the drawings, but the present invention is not limited to this example in any way, and it is of course possible to carry out the invention in various forms within the scope of the gist of the present invention.

[0048] FIG. 2 shows a conceptual diagram of a plasma irradiation head in a plasma jet processing apparatus usable in the present invention. The plasma irradiation head 31 blows plasma generated in a reaction chamber 33 toward a processing target (sample 38) located outside the plasma irradiation head 31, making it a so-called remote-type plasma processing apparatus. The plasma irradiation head 31 has a pair of electrodes 32, 32 arranged opposite each other, one of which is connected to a power source and the other is electrically grounded (power source and ground are not shown). Plasma can be generated by supplying voltage from the power source while gas is flowing into the reaction chamber 33. In the plasma irradiation head 31, processing gas G is introduced from a gas supply device 34 into an inlet (gas inlet) 35 to generate plasma (i.e., processing gas converted into plasma). The plasma is then blown out from a gas outlet 37 formed in a body 36 and sprayed onto the surface of a sample (gel body) 38 located below the gas outlet 37. Because the area below gas outlet 37 is not sealed, atmospheric air flows in, and the oxygen concentration near sample 38 is higher than the oxygen concentration in gas G near inlet channel 35. At least one gas selected from the group consisting of nitrogen and air can be used as gas G. The distance between gas outlet 37 and the surface of sample 38 is preferably 50 mm or less, and more preferably 20 mm or less. By moving the stage 39 up, down, left, and right, the desired portion of the sample 38 can be irradiated with plasma. For example, the moving speed of the stage 39 is preferably 0.5 to 10 mm / sec, but the present invention is not limited to this example. The time for which the sample 38 is irradiated with plasma can be adjusted, for example, by varying the moving speed of the stage 39 or by moving the stage 39 back and forth a desired number of times.

[0049] 3. Contact and adhesion process between resin body and gel body When the modified surface of the surface-modified resin body and the modified surface of the surface-modified gel body are brought into contact with each other and subjected to thermocompression bonding (heating and pressure), the two bodies can be directly bonded. This results in a bonded body of a resin body and a gel body. The thermocompression bonding method is not particularly limited as long as the gel is not destroyed during thermocompression bonding. For example, heating and pressure treatment can be performed at a heating temperature of 120 to 200°C and a pressure of 0.3 to 10 MPa for approximately 5 to 40 minutes.

[0050] The mechanism by which the resin body and the gel body are bonded (adhered) and good adhesive strength is achieved is thought to be as follows, but is not limited to the following mechanism. By performing high-power plasma treatment on the surface of a resin body, more C-OH groups and COOH groups (carboxyl groups) are formed due to peroxide radicals introduced into the surface of the resin body than when plasma treatment is performed at low power. On the other hand, by performing plasma treatment on the surface of a gel body, C-OH groups and COOH groups (carboxyl groups) are formed on the surface of the gel body. By modifying the surfaces of the resin body and gel body in this way, the adhesion between the resin body and the gel body can be improved. Furthermore, when the gel body also contains lipophilic silica particles, as described above, it becomes a hard and strong gel body, thereby increasing the mechanical strength of the gel. As a result, the gel body is prevented from breaking when the laminate is detached from the adherend, resulting in a laminate that can be attached and detached to the adherend and used.

[0051] In the resin body, it is preferable that the surfaces of the resin body and the gel body are plasma-treated, and the plasma-treated surface of the resin body and the plasma-treated surface of the gel body are directly bonded together. By performing the plasma treatment, it is possible to obtain a laminate with excellent adhesive strength without the need for surface modification other than the plasma treatment. Furthermore, the resin body and the gel body can be directly bonded (laminated) together without laminating another layer between them.

[0052] 4. Method for producing the laminate of the present invention without performing plasma treatment on the surface of the gel body Instead of steps 2 and 3 above, the adhesive strength can also be increased by laminating an uncured gel-like material and a surface-modified resin body, then heat-curing the gel-like material to form a gel. For example, a laminate can be produced by placing a surface-modified resin body in a mold, filling a gel-like material containing silicone gel and lipophilic silica particles on top of the surface-modified resin body, and then heat-curing the material to form a gel. Alternatively, a laminate can be produced by filling a gel-like material containing silicone gel and lipophilic silica particles in a mold, laminating a surface-modified resin body on top of the gel-like material, and then heat-curing the material to form a gel. The heat-curing process generates silanol groups on the surface of the gel body, which interact (by chemical or hydrogen bonding) with oxygen-containing functional groups and COO* (peroxide radicals) present near the surface of the plasma-treated resin body. Therefore, it is estimated that adhesive strength of 0.4 N / mm or more can be achieved even if a laminate is produced using step (II) above instead of step (I) above (steps 2 and 3 above).

[0053] <Other> AFM-IR, a device that combines the surface morphology observation capabilities of atomic force microscopy (AFM) with the functional group identification capabilities of infrared spectroscopy (IR), has an extremely high spatial resolution of approximately 10 nm and can reveal not only information about surface morphology but also the distribution of functional groups present on the surface. Analysis of the cross section of a laminate of the present invention (e.g., a laminate of a PTFE sheet and a silicone gel sheet, as described in the Examples below) using AFM-IR not only identifies the materials constituting the laminate, but also the depth of surface modification (100 nm or less) and interfacial roughness (200 nm or less) due to plasma treatment, enabling reverse engineering. Therefore, by comprehensively assessing the multiple data obtained using the above device, it can be determined that no surface modification other than plasma treatment has been performed on the surface of the resin body on which the gel body is laminated. [Example]

[0054] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and can of course be practiced with appropriate modifications within the scope of the above and below-described aims, and all such modifications are within the technical scope of the present invention.

[0055] Example 1 A PTFE sheet and a silicone gel sheet were prepared as follows.

[0056] <PTFEシート> (A-1) Cleaning A PTFE sheet (Nitoflon No. 900UL) cut to a thickness of 0.2 mm by Nitto Denko Corporation was prepared and cut into pieces of a fixed size (width: 4.5 cm x length: 7 cm). This resin body was ultrasonically cleaned in acetone for 1 minute, and then ultrasonically cleaned in pure water for 1 minute. The pure water adhering to the PTFE sheet was then removed by spraying nitrogen gas (purity: 99% or higher) with an air gun.

[0057] (A-2) High-temperature plasma treatment Using a plasma generator (manufactured by Meisho Kiko Co., Ltd., product name K2X02L023) having the configuration shown in FIG. 1, the surface of the PTFE sheet that had been cleaned in (A-1) above was modified with plasma. The high-frequency power supply for the plasma generator had an applied voltage frequency of 13.56 MHz. The electrode consisted of a copper tube with an inner diameter of 1.8 mm, an outer diameter of 3 mm, and a length of 165 mm, covered with an alumina tube with an outer diameter of 5 mm, a thickness of 1 mm, and a length of 145 mm. The sample holder was a cylindrical aluminum alloy with a diameter of 50 mm and a width of 3.4 cm. A PTFE sheet was placed on the top of the sample holder, and the distance between the resin surface and the electrode was set to 1.0 mm. The chamber was sealed and the pressure was reduced to 10 Pa using a rotary pump, after which helium gas was introduced until the pressure reached atmospheric pressure (1013 hPa). After that, the output power density reached 19.1 W / cm 2 The high-frequency power supply was set to 0.05 V, and the scanning stage was set to move at a speed of 2 mm / sec, with the electrode passing 30 mm along the length of the resin body. The high-frequency power supply was then activated, and the scanning stage was moved to irradiate the resin body with plasma within a 1.0 cm wide x 3.4 cm long area. The plasma irradiation time was determined by 60 30 mm longitudinal movements of the scanning stage (60 round trips). The oxygen concentration near the surface of the PTFE sheet (plasma-irradiated area) was measured using a zirconia oxygen concentration meter (LC-300, manufactured by Toray Engineering Co., Ltd.) and found to be 25.7 ppm, well below 0.5% by volume. The surface temperature of the resin body during plasma treatment was measured using a radiation thermometer (FT-H40K and FT-50A, manufactured by Keyence Corporation) and found to be 203°C.

[0058] <Silicone gel sheet> (B-1) Preparation of silicone gel sheet Wacker's SILGEL 612, a two-component addition-cure thermosetting liquid silicone gel, and Tosoh Silica Corporation's Nipsil (registered trademark) SS-30P, lipophilic silica particles, were mixed and then heated and cured at 80°C for 60 minutes to produce a silicone gel sheet measuring 4.8 cm wide, 10 cm long, and 13 mm thick. The two-component system of SILGEL 612, components A and B, was formulated so that 100 parts by mass of component A was combined with 63.4 parts by mass of component B, and 100 g of SILGEL 612 and 15 g of SS-30P were added.

[0059] The penetration of the silicone gel was measured in accordance with JIS K2220 using a Rigo Co., Ltd. (Model: 840I-01) device. The liquid (pre-cured) gel was poured into a 48 mm inner diameter glass container to a height of 40 mm or more and heated at 80°C for 60 minutes to cure the gel. A 9.38 g quarter-circular cone was then used to align the tip of the cone's needle with the sample surface, allowing the cone to penetrate the sample by free fall. After 5 seconds, the penetration distance from the sample surface was measured. The penetration distance was measured three times and the average value was calculated in millimeters. The penetration value was calculated as 10 times the average value (0.1 mm was converted to a penetration value of 1). The penetration value of the silicone gel sheet prepared in the above "(B-1) Preparation of Silicone Gel Sheet" was 10. The penetration measurement was performed without adding silica particles.

[0060] (B-2) Plasma jet treatment Using an ultra-high density atmospheric pressure plasma unit (Tough Plasma FPE20 manufactured by FUJI CORPORATION) having the configuration shown in FIG. 2, the surface of the silicone gel sheet obtained in (B-1) above was modified by plasma jet treatment. The flow rate of nitrogen gas into the plasma irradiation area was 29.7 L / min, and the flow rate of air was 0.3 L / min, meaning that if the total flow rate of nitrogen gas and air was 100%, the proportion of air was 1.0% and the proportion of oxygen was 0.2%. However, since the device was not sealed and air flowed in near the silicone gel body, the oxygen concentration in the plasma irradiation area was measured using a zirconia oxygen concentration meter LC-300 manufactured by Toray Engineering Co., Ltd. and was found to be 11.3% by volume. The distance between the plasma nozzle and the silicone gel was 20 mm, the stage movement speed was 8 mm / sec, and the plasma jet treatment was performed only once without moving the stage back and forth.

[0061] (C) Fabrication of laminate The plasma-treated surface of the PTFE sheet was brought into contact with the plasma-treated surface of the silicone gel sheet, and heated and pressurized for 10 minutes at a temperature of 140°C and a pressure of 0.5 MPa so that the bonded area was 20 mm x 30 mm and the unbonded area (gripping area) was 10 mm x 30 mm, producing a laminate of the PTFE sheet and the silicone gel sheet.

[0062] Using a digital force gauge (ZP-200N, manufactured by Imada Manufacturing Co., Ltd.) in combination with an electric stand (MX-500N, manufactured by Imada Manufacturing Co., Ltd.), the gripping margin was clamped in a chuck, and the PTFE sheet and silicone gel sheet were pulled in a 180-degree direction to perform a T-peel test and measure the adhesive strength between the PTFE sheet and the silicone gel sheet. The load cell was 1 kN, and the pulling speed was 60 mm / min. The adhesive strength was 1.12 N / mm. Note that in all Examples and Comparative Examples except for Comparative Examples 3 and 4 described below, material failure occurred within the silicone gel sheet during adhesive strength measurement, and no failure (peel) occurred at the interface between the PTFE sheet and the silicone gel sheet.

[0063] Furthermore, the laminate of Example 1 was adhered to an aluminum substrate (A1050, manufactured by UACJ Corporation) and immediately detached, and this cycle was repeated 10 times in a row. However, even after 10 attachments and detachments, there was no peeling at the interface between the resin body and the gel body, and no material damage occurred within the silicone gel sheet, and the laminate remained unchanged after 10 attachments and detachments. In Examples 2 to 5 described below, attachments and detachments similar to those of Example 1 were performed, and similar results to those of Example 1 were obtained.

[0064] Example 2 A laminate was prepared in the same manner as in Example 1, except that the thickness of the silicone gel sheet was changed to 3.5 mm, and the adhesive strength was measured. The adhesive strength was 0.84 N / mm. Note that the adhesive strength measurement method described above was also used for Examples and Comparative Examples other than Example 1.

[0065] (Comparative Example 1) A laminate was produced in the same manner as in Example 1, except that no lipophilic silica particles were added, and the adhesive strength was measured. The adhesive strength was 0.34 N / mm.

[0066] (Comparative Example 2) A laminate was produced in the same manner as in Example 2, except that no lipophilic silica particles were added, and the adhesive strength was measured. The adhesive strength was 0.21 N / mm.

[0067] Example 3 A laminate was prepared in the same manner as in Example 1, except that "(B-1) Preparation of Silicone Gel Sheet" was changed to the manufacturing method described below in "(B-1') Preparation of Silicone Gel Sheet," and the adhesive strength was measured. The adhesive strength was 0.52 N / mm. The needle penetration of the silicone gel sheet prepared in "(B-1') Preparation of Silicone Gel Sheet," described below, was calculated using the above-mentioned method and was found to be 40.

[0068] (B-1') Preparation of silicone gel sheet 100 g of addition-curing thermosetting liquid silicone gel (KE-1062 manufactured by Shin-Etsu Chemical Co., Ltd., viscosity at 23°C: 700 mPa·s, containing a platinum catalyst) and 15 g of lipophilic silica particles (Nipsil® SS-30P manufactured by Tosoh Silica Corporation) were added to a mold and stirred for 1 minute. The mold filled with the silicone gel was then heated in an oven at 120°C for 30 minutes to produce a silicone gel sheet measuring 4.8 cm wide, 10 cm long, and 13 mm thick.

[0069] Example 4 A laminate was prepared in the same manner as in Example 3, except that 25 g of lipophilic silica particles were added to (B-1') above, and the lipophilic silica particles were added to the silicone gel sheet so that 25 parts by mass of the lipophilic silica particles were added per 100 parts by mass of silicone gel, and the adhesive strength was measured. The adhesive strength was 1.06 N / mm.

[0070] (Comparative Example 3) In the above (B-1'), an attempt was made to prepare a laminate in the same manner as in Example 3, except that 30 parts by mass of oil-soluble silica particles were added to 100 parts by mass of silicone gel. However, a large number of air bubbles were generated in the silicone gel sheet, and the silicone gel sheet could not be adhered to the PTFE sheet.

[0071] Comparative Example 4 A laminate was prepared in the same manner as in Example 4, except that the plasma jet treatment (B-2) above was not performed, and the adhesive strength was measured. The adhesive strength was 0.02 N / mm. In Comparative Example 4, when the adhesive strength was measured, damage (peeling) occurred at the interface between the PTFE sheet and the silicone gel sheet, but no material damage occurred in the silicone gel sheet.

[0072] (Comparative Example 5) A laminate was prepared in the same manner as in Example 4, except that hydrophilic silica particles, Nipsil® VN3 manufactured by Tosoh Silica Corporation, were used instead of the lipophilic silica particles. Because the silicone gel contained oil, the hydrophilic silica did not blend with the silicone gel. During the process of preparing the silicone gel sheet, air bubbles were generated when the hydrophilic silica and silicone gel were stirred, and the air bubbles did not disappear even after time had passed. Furthermore, due to the presence of air bubbles in the silicone gel sheet, the adhesive strength was low at 0.09 N / mm.

[0073] (Comparative Example 6) A laminate was produced in the same manner as in Example 4, except that no lipophilic silica particles were added, and the adhesive strength was measured. The adhesive strength was 0.06 N / mm.

[0074] (Comparative Example 7) A laminate was prepared in the same manner as in Comparative Example 6, except that the thickness of the silicone gel sheet was changed to 3.5 mm, and the adhesive strength was measured. The adhesive strength was 0.04 N / mm.

[0075] Example 5 A laminate was produced in the same manner as in Example 3, except that the steps "(B-1) Preparation of Silicone Gel Sheet" to "(C) Preparation of Laminate" were changed to the manufacturing method described below in "(D) Preparation of Silicone Gel Sheet and Laminate," and the adhesive strength was measured. The adhesive strength of Example 5 was 0.49 N / mm, which is approximately the same as that of Example 3, which differs from Example 5 only in the manufacturing method, and it was found that the same adhesive strength could be obtained even if the manufacturing method (I) above was changed to the manufacturing method (II) above.

[0076] (D) Preparation of silicone gel sheets and laminates 100 g of addition-curing thermosetting liquid silicone gel (KE-1062 manufactured by Shin-Etsu Chemical Co., Ltd., viscosity at 23°C: 700 mPa·s, containing a platinum catalyst) and 15 g of Nipsil® SS-30P lipophilic silica particles manufactured by Tosoh Silica Corporation were added and stirred for 1 minute. The plasma-treated PTFE sheet prepared by the manufacturing methods (A-1) and (A-2) above was placed in a mold and then filled with silicone gel. The mold containing the PTFE sheet and silicone gel was then heated in an oven at 120°C for 30 minutes to produce a laminate of the PTFE sheet and silicone gel measuring 4.8 cm wide, 10 cm long, and 13 mm thick.

[0077] The compositions and physical properties of the laminates of Examples 1 to 5 and Comparative Examples 1 to 7 are shown in Table 1. The numbers (I) and (II) listed in the production method column refer to the numbers used in the description of the production method for the laminate of the present invention.

[0078] [Table 1]

[0079] Furthermore, the loss factor tanδ was measured for Example 4, which contained 25% by mass of lipophilic silica particles; Example 3, which was the same as Example 4 except that 15% by mass of lipophilic silica particles was added; and Comparative Example 6, which was the same as Example 4 except that no lipophilic silica particles were added. The loss factor tanδ for Example 4 was 0.465, the loss factor tanδ for Example 3 was 0.549, and the loss factor tanδ for Comparative Example 6 was 0.592. This indicates that the greater the amount of lipophilic silica particles added, the smaller the contribution of viscosity, resulting in a harder and stronger gel. The loss factor tanδ was measured using a Rheogel-E4000 (manufactured by UBM Corporation) in compression measurement mode under conditions of a strain of 20 μm, a frequency of 10 Hz, and a measurement time of 5 minutes. [Explanation of symbols]

[0080] 10 High frequency power supply 11 Matching Unit 12 chambers 13 Vacuum exhaust system 14 electrodes 15 Electrode lifting mechanism 16 Cylindrical rotation stage and sample holder 17 Halogen heater 18 Inner tube 19 Outer tube 20 samples (resin body including fluororesin) 21 Radiation thermometer 31 Plasma irradiation head 32 electrodes 33 Reaction Chamber 34 Gas supply equipment 35 Inlet (gas inlet) 36 skeleton 37 Gas outlet 38 Sample (gel body) 39 Stages G Gas

Claims

1. A laminate of a resin body and a gel body, wherein the resin body contains a fluorine-based resin, the gel body contains silicone gel and lipophilic silica particles, the gel body contains 5 to 27 parts by mass of the lipophilic silica particles per 100 parts by mass of the silicone gel, and the adhesive strength between the resin body and the gel body is 0.4 N / mm or more.

2. 2. The laminate according to claim 1, wherein the surfaces of the lipophilic silica particles are modified with at least one of dialkylsilane, trialkylsilane, polysiloxane, aminosilane, and polysilazane.

3. 3. The laminate according to claim 1, wherein the fluororesin is a copolymer of at least one of a hexafluoropropylene unit, a perfluoroalkyl vinyl ether unit, a methylene unit, an ethylene unit, and a perfluorodioxole unit with at least one of a difluoromethylene unit and a tetrafluoroethylene unit, or polytetrafluoroethylene.

4. The laminate according to any one of claims 1 to 3, wherein the surface of the resin body is plasma-treated.

5. A method for producing a laminate of a resin body and a gel body, comprising: a step of making the oxygen concentration near the surface of the resin body less than 0.5% by volume and performing a plasma treatment on the surface of the resin body to produce a surface-modified resin body; and either step (I) or (II) below:

10. A method for manufacturing a laminate, wherein the resin body contains a fluorine-based resin, and the gel body contains a silicone gel and lipophilic silica particles. (I) A step of setting the oxygen concentration near the surface of the heat-cured gel body to 1% by volume or more, performing plasma treatment on the surface of the gel body to produce a surface-modified gel body, and then laminating the surface-modified gel body and the surface-modified resin body. (II) A step of laminating a gel-like material and the surface-modified resin body, and then heat-curing the gel-like material to form the gel body.

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