Waterproof member, electronic apparatus, and member provision assembly

Abstract

A waterproof member 10 is disposed so as to block an opening 51 in an object 50 that has an opening surface 51s in which the opening 51 is formed. The waterproof member 10 comprises: a first waterproof film 11 that has a first principal surface 11a facing the opening 51 and a second principal surface 11b on the reverse side from the first principal surface 11a when disposed so as to close the opening 51; a second waterproof film 12 that is disposed so as to be separated from the first waterproof film 11 and has a first principal surface 12a facing the second principal surface 11b of the first waterproof film 11 and a second principal surface 12b on the reverse side from the first principal surface 12a; and an inner pressure-sensitive adhesive layer 21 joined to the second principal surface 11b of the first waterproof film 11 and the first principal surface 12a of the second waterproof film 12. The storage elastic modulus G' of the inner pressure-sensitive adhesive layer 21 at 25°C is 0.27 MPa or less.

Description

Waterproofing components, electronic equipment, and component supply assemblies

[0001] The present invention relates to waterproofing members, electronic equipment, and member supply assemblies.

[0002] Electronic devices equipped with sound-producing parts such as speakers and buzzers, and sound-receiving parts such as microphones (acoustic components), include many portable devices used outdoors, such as smartwatches and other wearable devices, smartphones, mobile phones, and digital cameras. In recent years, there has been a demand for electronic devices equipped with such acoustic components to have waterproof functionality while ensuring sound transmission characteristics. Waterproof smartwatches and waterproof smartphones are already widespread, and filters with waterproof sound transmission functionality (waterproof sound-transmitting members) are used to protect the acoustic parts (acoustic components) of these devices.

[0003] Conventionally, microporous membranes made of polytetrafluoroethylene (PTFE) or the like have been proposed as waterproof materials with sound-permeable properties (see, for example, Patent Document 1). In recent years, waterproof protective cover members (waterproof materials) have been proposed for placement over openings in micro-products such as micro-electro-mechanical systems (MEMS) (see, for example, Patent Document 2).

[0004] Special table 2003-503991 publication Special table 2018-501972 publication

[0005] However, there is a trade-off between waterproofing and sound permeability. Until now, achieving both has been difficult. Waterproofing materials, as described above, deserve re-examination from the perspective of achieving both waterproofing and sound permeability.

[0006] Therefore, the present invention aims to provide a waterproof member suitable for achieving both waterproofness and sound transmission characteristics, an electronic device equipped therewith, and a member supply assembly.

[0007] The present invention provides a waterproof member that is disposed to close an opening in an object having an opening surface, comprising: a first waterproof membrane having a first main surface facing the opening and a second main surface opposite to the first main surface when disposed to close the opening; a second waterproof membrane disposed spaced apart from the first waterproof membrane and having a first main surface facing the second main surface of the first waterproof membrane and a second main surface opposite to the first main surface; and an inner adhesive layer bonded to the second main surface of the first waterproof membrane and the first main surface of the second waterproof membrane, wherein the storage modulus G' of the inner adhesive layer at 25°C is 0.27 MPa or less.

[0008] In another aspect, the present invention provides an electronic device comprising a housing having an opening formed therein, and a waterproof member of the present invention disposed on the housing so as to close the opening.

[0009] In yet another aspect, the present invention provides a component supply assembly comprising: a waterproof member disposed to close an opening in an object having an opening surface in which an opening is formed; and a base sheet on which the waterproof member is disposed, wherein the waterproof member is the waterproof member of the present invention.

[0010] According to the present invention, it is possible to provide a waterproof member suitable for achieving both waterproofness and sound transmission characteristics, an electronic device equipped with the same, and a member supply assembly.

[0011] Figure 1A is a schematic cross-sectional view showing an example of a waterproof member according to the first embodiment of the present invention. Figure 1B is a schematic perspective view showing the waterproof member of Figure 1A. Figure 1C is a cross-sectional view showing an example of the waterproof member of Figure 1A being arranged to cover an opening in an object. Figure 2A is a schematic cross-sectional view showing a modification 1 of the waterproof member according to the first embodiment of the present invention. Figure 2B is a schematic perspective view showing the waterproof member of Figure 2A. Figure 2C is a cross-sectional view showing an example of the waterproof member of Figure 2A being arranged to cover an opening in an object. Figure 3A is a schematic cross-sectional view showing a modification 2 of the waterproof member according to the first embodiment of the present invention. Figure 3B is a schematic perspective view showing the waterproof member of Figure 3A. Figure 3C is a cross-sectional view showing an example of the waterproof member of Figure 3A being arranged to cover an opening in an object. Figure 4 is a schematic front view showing an example of an electronic device according to the second embodiment of the present invention. Figure 5 is a schematic cross-sectional view showing an example of a component supply assembly according to the third embodiment of the present invention. Figure 6 is a schematic cross-sectional view showing a modification of the component supply assembly according to the third embodiment of the present invention. Figure 7 is a cross-sectional view showing the configuration of the waterproofing members of Examples 1 to 13 and Comparative Examples 3 to 6. Figure 8 is a cross-sectional view showing the configuration of the waterproofing members of Comparative Examples 1 to 2. Figure 9 is a schematic diagram illustrating a method for evaluating the insertion loss of the waterproofing member. Figure 10 is a diagram showing the relationship between the insertion loss and frequency of the waterproofing members of Examples 1 to 13. Figure 11 is a diagram showing the relationship between the insertion loss and frequency of the waterproofing members of Examples 14 to 15. Figure 12 is a diagram showing the relationship between the insertion loss and frequency of the waterproofing members of Comparative Examples 1 to 6.

[0012] A waterproof member according to a first aspect of the present invention is a waterproof member disposed to close an opening in an object having an opening surface, comprising: a first waterproof membrane having a first main surface facing the opening and a second main surface opposite to the first main surface when disposed to close the opening; a second waterproof membrane disposed spaced apart from the first waterproof membrane and having a first main surface facing the second main surface of the first waterproof membrane and a second main surface opposite to the first main surface; and an inner adhesive layer bonded to the second main surface of the first waterproof membrane and the first main surface of the second waterproof membrane, wherein the storage modulus G' of the inner adhesive layer at 25°C is 0.27 MPa or less.

[0013] In a second aspect of the present invention, for example, the waterproof member according to the first aspect further comprises a first outer adhesive layer bonded to the first main surface of the first waterproof membrane, wherein the storage modulus G' of the first outer adhesive layer at 25°C is equal to or greater than the storage modulus G' of the inner adhesive layer at 25°C.

[0014] In a third aspect of the present invention, for example, the waterproofing member according to the second aspect further comprises a second outer adhesive layer bonded to the second main surface of the second waterproofing membrane, wherein the storage modulus G' of the second outer adhesive layer at 25°C is greater than the storage modulus G' of the inner adhesive layer at 25°C.

[0015] In a fourth aspect of the present invention, for example, in the waterproof member according to the third aspect, the storage modulus G' of the first outer adhesive layer at 25°C and the storage modulus G' of the second outer adhesive layer at 25°C are 0.20 MPa or more.

[0016] In a fifth embodiment of the present invention, for example, in a waterproof member according to the third or fourth embodiment, at least one selected from the group consisting of the thickness of the first outer adhesive layer and the thickness of the second outer adhesive layer is equal to or greater than the thickness of the inner adhesive layer.

[0017] In a sixth embodiment of the present invention, for example, in the waterproof member according to the fifth embodiment, the thickness of the inner adhesive layer is 30 μm or more and 150 μm or less.

[0018] In a seventh aspect of the present invention, for example, a waterproof member according to any one of the first to sixth aspects has an insertion loss of 7.5 dB or less in the frequency range of 1000 to 10000 Hz.

[0019] In the eighth aspect of the present invention, for example, a waterproof member according to any one of the first to seventh aspects has water retention resistance capable of withstanding a water pressure retention test in which it is exposed to pure water at a water pressure of 1.0 MPa for 30 minutes when a circular water pressure application surface with a diameter of 1.6 mm is set.

[0020] In the ninth aspect of the present invention, for example, a waterproof member according to any one of the first to eighth aspects has water retention resistance capable of withstanding a water pressure retention test in which a circular water pressure application surface with a diameter of 1.6 mm is set and the member is exposed to soapy water (soap concentration of 0.5 wt%) at a water pressure of 0.5 MPa for 10 minutes.

[0021] In the tenth embodiment of the present invention, for example, in a waterproof member according to any one of the first to ninth embodiments, the first waterproof membrane and the second waterproof membrane each include at least one selected from the group consisting of polytetrafluoroethylene, polyolefin, polyimide, silicone, polyurethane, and polyethylene terephthalate.

[0022] In the eleventh aspect of the present invention, for example, in a waterproofing member according to any one of the first to tenth aspects, the first waterproofing membrane and the second waterproofing membrane are porous membranes or non-porous membranes.

[0023] An electronic device according to a twelfth aspect of the present invention comprises a housing having an opening formed therein, and a waterproof member according to any one of the first to eleventh aspects, disposed on the housing so as to close the opening.

[0024] A member supply assembly according to a thirteenth aspect of the present invention is a member supply assembly comprising a waterproof member disposed to close an opening in an object having an opening surface, and a base sheet on which the waterproof member is disposed, wherein the waterproof member is a waterproof member according to any one of the first to eleventh aspects.

[0025] Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the following embodiments.

[0026] (First Embodiment) [Waterproof Member] An example of a waterproof member 10 according to the first embodiment is shown in Figures 1A to 1B. The waterproof member 10A shown in Figures 1A to 1B comprises a first waterproof membrane 11, a second waterproof membrane 12, and an inner adhesive layer 21 that joins the first waterproof membrane 11 and the second waterproof membrane 12. Figure 1C is a cross-sectional view showing an example of a state in which the waterproof member 10A is arranged to close an opening 51 of an object 50. As shown in Figure 1C, the waterproof member 10A is used by being arranged to close an opening 51 of an object 50 having an opening surface 51s in which the opening 51 is formed. The waterproof member 10A is fixed to the object 50 by, for example, an adhesive layer 30. In this specification, "opening surface" means a surface in which an opening is formed, and means a surface having an opening. The opening 51 provided in the object 50 is, for example, provided at a position corresponding to an acoustic component for the purpose of transmitting sound. The object 50 includes, for example, audio equipment such as microphones and speakers, and products such as micro-electromechanical systems (MEMS).

[0027] The first waterproof membrane 11 and the second waterproof membrane 12 are membranes that prevent water from entering while allowing sound to pass through. The first waterproof membrane 11 has a shape that closes the opening 51. When positioned to close the opening 51, the first waterproof membrane 11 has a first main surface 11a facing the opening 51 and a second main surface 11b opposite to the first main surface 11a. The second waterproof membrane 12 is positioned spaced apart from the first waterproof membrane 11. The second waterproof membrane 12 has a first main surface 12a facing the second main surface 11b of the first waterproof membrane 11 and a second main surface 12b opposite to the first main surface 12a. In this specification, "facing the opening" means facing the opening and is not limited to cases where two members face each other, but also includes cases where another member exists between the two members. In this specification, "main surface" means the surface of the sheet-like member that has the largest area.

[0028] The inner adhesive layer 21 is bonded to the second main surface 11b of the first waterproof membrane 11 and the first main surface 12a of the second waterproof membrane 12. In this embodiment, the inner adhesive layer 21 is positioned on the peripheral edge of the second main surface 11b of the first waterproof membrane 11 and on the first main surface 12a of the second waterproof membrane 12. In Figure 1A, reference numeral 40 indicates the region through which sound is transmitted when the waterproof member 10A is installed in equipment, i.e., the sound transmission region (sound-transmitting region).

[0029] In this embodiment, the storage modulus G' of the inner adhesive layer 21 at 25°C is 0.27 MPa or less.

[0030] The inventors of the present invention discovered a new problem: while a two-layer structure for a waterproof membrane can improve the water resistance of the waterproof member, it can also reduce the sound transmission characteristics of the waterproof member. Therefore, the inventors investigated this problem and focused on the bonding material between the first and second waterproof membranes. The vibration velocity of the waterproof membrane affects its sound transmission characteristics. Specifically, as the vibration velocity of the waterproof membrane increases, the insertion loss decreases, and the sound transmission characteristics of the waterproof membrane improve. Based on these findings, the inventors conceived of using a viscous adhesive layer having a storage modulus G' within a specific range as the bonding material between the first and second waterproof membranes in order to suppress the decrease in the vibration velocity of the waterproof membrane. Furthermore, we have found that a waterproof member 10A comprising a first waterproof membrane 11, a second waterproof membrane 12, and an inner adhesive layer 21 that joins the first waterproof membrane 11 and the second waterproof membrane 12, wherein the storage modulus G' of the inner adhesive layer 21 at 25°C is adjusted to 0.27 MPa or less, can improve water resistance due to the two-layer structure of the waterproof membrane, and can reduce the insertion loss of the first waterproof membrane 11 and the second waterproof membrane 12 by the inner adhesive layer 21 having a predetermined storage modulus G', thus completing the present invention. As a result, the waterproof member 10A is suitable for achieving both waterproofness and sound permeability.

[0031] Since the waterproofing member 10A is suitable for achieving both waterproofing and sound-permeable properties, it can function as, for example, a waterproof and sound-permeable member. In other words, the waterproofing member 10A can be a waterproof and sound-permeable member.

[0032] In this specification, "adhesion" means "adhesion" or "bonding." For example, "adhesive layer" means "adhesive layer" or "adhesive layer."

[0033] In this specification, "pressure-sensitive adhesive" refers to a type of adhesion as defined in JIS (Japanese Industrial Standards), specifically a temporary adhesive that can bond with only slight pressure. It also possesses cohesive force and elasticity, meaning it can bond strongly while also being able to be peeled from hard, smooth surfaces. The adhesive is a soft solid and does not change state like a conventional adhesive. Because the adhesive wets the substrate and resists peeling, it can instantly exert practical adhesive strength when substrates are joined together. In other words, the adhesive combines the properties of a liquid (fluidity) to wet the substrate and the properties of a solid (cohesive force) to resist peeling. Since the adhesive is a soft solid, applying pressure or allowing time to pass gradually increases the contact area with the substrate. Because it can maintain this softness for a long time, it has the property of being removable when desired.

[0034] In this specification, "adhesive" refers to the property of bonding and integrating surfaces of the same or different types of solids, as defined in JIS (Japanese Industrial Standards). When bonding adherends together, adhesives are fluid substances that wet and conform to the adherends. Subsequently, they change into a solid through heating or chemical reactions, forming a strong bond at the interface between the adherends and exhibiting resistance to peeling. In other words, adhesives wet with a fluid substance and bond as a solid.

[0035] In the waterproof member 10A, the upper limit of the storage modulus G' of the inner adhesive layer 21 at 25°C may be 0.26 MPa or less, 0.25 MPa or less, 0.25 MPa or less, or even 0.24 MPa or less. The lower limit of the storage modulus G' of the inner adhesive layer 21 at 25°C is, for example, 0.05 MPa or more. The lower limit of the storage modulus G' of the inner adhesive layer 21 at 25°C may be 0.06 MPa or more, 0.07 MPa or more, 0.08 MPa or more, or even 0.09 MPa or more.

[0036] (Method for Measuring Storage Elastic Modulus G') The storage elastic modulus G' of the inner adhesive layer 21 at 25°C can be measured by dynamic viscoelasticity measurement. Specifically, a plurality of inner adhesive layers 21 to be measured are stacked to produce a laminate with a thickness of about 2 mm. A sample obtained by punching out this laminate into a disc shape with a diameter of 7.9 mm is sandwiched and fixed between parallel plates, and dynamic viscoelasticity measurement is performed in an environment of 25°C using a viscoelasticity tester (for example, ARES manufactured by TA Instruments or its equivalent). From the results of the dynamic viscoelasticity measurement, the storage elastic modulus G' of the inner adhesive layer 21 at 25°C can be measured.

[0037] The conditions for the dynamic viscoelasticity measurement are as follows. - Measurement condition frequency: 1 Hz Deformation mode: Shear mode Measurement temperature: -70°C to 150°C Heating rate: 5°C / min

[0038] As long as the storage elastic modulus G' at 25°C is 0.27 MPa or less, the adhesive constituting the inner adhesive layer 21 is not particularly limited. The adhesive constituting the inner adhesive layer 21 can be appropriately selected so that the first waterproof film 11 and the second waterproof film 12 can be joined. As the inner adhesive layer 21, for example, a general-purpose double-sided tape with a base material, a double-sided tape without a base material (that is, a tape composed only of an adhesive), etc. can be appropriately adopted. The adhesive constituting the inner adhesive layer 21 will be described later.

[0039] In the example shown in FIGS. 1A to 1B, when viewed from a direction perpendicular to the main surfaces of the first waterproof film 11 and the second waterproof film 12, the waterproof member 10A is circular. However, the shape of the waterproof member 10A is not limited to the example shown in FIGS. 1A to 1B. The shape of the waterproof member 10A may be a circle (including a substantially circle), an ellipse (including a substantially ellipse), and a polygon including a rectangle and a square. The corners of the polygon may be rounded.

[0040] In the example shown in FIGS. 1A to 1B, when viewed from a direction perpendicular to the main surfaces of the first waterproof film 11 and the second waterproof film 12, the inner adhesive layer 21 is annular. However, the shape of the inner adhesive layer 21 is not limited to the example shown in FIGS. 1A to 1B.

[0041] The waterproof member 10A has an insertion loss of 7.5 dB or less, for example, in the frequency range of 1000 to 10000 Hz.

[0042] The lower limit of the insertion loss of the waterproof member 10A is not particularly limited. The lower limit of the insertion loss is, for example, 0.5 dB.

[0043] The method for evaluating the insertion loss of the waterproof member 10A for sounds in the frequency range of 1000 to 10000 Hz will be described in the examples.

[0044] The first waterproof film 11 and the second waterproof film 12 may contain a fluororesin as a main component. The fluororesin may be PTFE. When the fluororesin is PTFE, it is easy to obtain the first waterproof film 11 and the second waterproof film 12 suitable for achieving both waterproofness and sound transmission characteristics. Also, since PTFE is particularly excellent in heat resistance, the heat resistance of the first waterproof film 11 and the second waterproof film 12 can be improved. In this specification, "containing as a main component" means that the content ratio (mass%) is the largest.

[0045] The first waterproof film 11 and the second waterproof film 12 may be a stretched porous film containing a fluororesin as a main component, particularly a PTFE stretched porous film. The PTFE stretched porous film is composed of fine fibrils of PTFE and may have nodes in which PTFE is aggregated compared to the fibrils. According to the PTFE stretched porous film, it is possible to achieve both waterproofness and sound transmission characteristics at a high level.

[0046] The first waterproof film 11 and the second waterproof film 12 may contain a thermoplastic resin不含氟 as a main component. The thermoplastic resin不含氟 may be a polyolefin. When the thermoplastic resin is a polyolefin, it is easy to obtain the first waterproof film 11 and the second waterproof film 12 suitable for achieving both waterproofness and sound transmission characteristics.

[0047] The polyolefin includes polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP).

[0048] Polyolefins may also be PMPs. PMPs are homopolymers or copolymers of poly(4-methylpentene-1), poly(3-methylpentene-1), etc. Copolymers include random copolymers and block copolymers. From the viewpoint of heat resistance and moldability, homopolymers of poly(4-methylpentene-1) are preferred.

[0049] The polyolefin may also be poly(4-methylpentene-1). Poly(4-methylpentene-1) means a homopolymer of 4-methylpentene-1, or a copolymer of 4-methylpentene-1 and at least one type of α-olefin. The composition ratio of 4-methylpentene-1 to α-olefin contained in the copolymer can be adjusted within a range of melting points of 180°C or higher.

[0050] The thermoplastic resin that does not contain fluorine may be a thermoplastic resin having a melting point of 180°C or higher and 300°C or lower. If the melting point of the thermoplastic resin is 180°C or higher, sufficient heat resistance can be ensured in the first waterproof film 11 and the second waterproof film 12. If the melting point of the thermoplastic resin is 300°C or lower, for example, the first waterproof film 11 and the second waterproof film 12 can be manufactured by melt molding.

[0051] The melting point of the thermoplastic resin may be 200°C or higher and 280°C or lower, and may be 220°C or higher and 260°C or lower.

[0052] The first waterproof membrane 11 and the second waterproof membrane 12 may be composed of a single raw material or a mixture of different raw materials.

[0053] The first waterproof membrane 11 and the second waterproof membrane 12 may each independently contain at least one selected from the group consisting of polytetrafluoroethylene (PTFE), polyolefin, polyimide (PI), silicone, polyurethane (PU), and polyethylene terephthalate (PET). The polyurethane (PU) may be thermoplastic polyurethane (TPU).

[0054] The first waterproof membrane 11 and the second waterproof membrane 12 can each be independently a porous membrane or a non-porous membrane.

[0055] The first waterproof membrane 11 and the second waterproof membrane 12 may be porous membranes. When the first waterproof membrane 11 and the second waterproof membrane 12 are porous membranes, the waterproof member 10A can, for example, easily exhibit breathability. In this case, the waterproof member 10A can also function as a breathable member.

[0056] The first waterproof membrane 11 and the second waterproof membrane 12 may be non-porous membranes. When the first waterproof membrane 11 and the second waterproof membrane 12 are non-porous membranes, the waterproof member 10A is particularly suitable for improving waterproof performance. In this specification, "non-porous" means that there are no pores connecting one main surface of the membrane to the other main surface, or that the number of pores is extremely small. For example, a membrane with an air permeability expressed in Gurley number greater than 10,000 seconds / 100 mL can be determined to be a non-porous membrane. Here, the Gurley number is a value obtained by measurement in accordance with JIS P8117:2009.

[0057] For example, polytetrafluoroethylene (PTFE), polyolefins, and polyimides (PI) are suitable for porous membranes. For example, silicone, polyurethane (PU), and polyethylene terephthalate (PET) are suitable for non-porous membranes.

[0058] The thickness of the first waterproof membrane 11 and the second waterproof membrane 12 is, for example, 5 μm or more and 40 μm or less. By having the thickness of the first waterproof membrane 11 and the second waterproof membrane 12 within the above range, sufficient waterproofness and strength can be ensured in the waterproof member 10A. The upper limit of the thickness of the first waterproof membrane 11 and the second waterproof membrane 12 may be 35 μm or 30 μm. The lower limit of the thickness of the first waterproof membrane 11 and the second waterproof membrane 12 is, for example, 7 μm. The thickness of the first waterproof membrane 11 and the thickness of the second waterproof membrane 12 may be the same or different, but it is preferable that they be the same.

[0059] (Method for measuring thickness) The thickness of the first waterproof membrane 11 can be determined by measuring the thickness at any five points on the first waterproof membrane 11 and taking the average of these measurements. The thickness of the second waterproof membrane 12 can be determined in the same manner.

[0060] The thickness of the inner adhesive layer 21 is, for example, 30 μm or more and 150 μm or less. By having the thickness of the inner adhesive layer 21 within the above range, the deterioration of the sound transmission characteristics of the waterproof member 10A can be further suppressed.

[0061] The thickness of the inner adhesive layer 21 can be determined by the same method as described above for determining the thickness of the first waterproof membrane 11.

[0062] For example, when the waterproof component 10A is applied to a smartwatch, the waterproof performance measured in accordance with ISO 22810:2010 is 2 meters or more. The lower limit of the above waterproof performance may be 10 meters or more, 20 meters or more, 30 meters or more, 40 meters or more, and even 50 meters or more. The upper limit of the above waterproof performance is, for example, 125 meters or less.

[0063] Another indicator of waterproofing performance for the waterproofing member 10A is its water retention resistance. Having water retention resistance against a predetermined water pressure and water pressure application time can be evaluated by ensuring that the first waterproofing membrane 11 does not rupture or leak even when a predetermined water pressure is continuously applied to the waterproofing member 10A for a predetermined period of time.

[0064] (Water pressure holding test) The water pressure holding test can be performed using a measuring jig and a water resistance testing device as exemplified in JIS L1092:2020. The water pressure application surface is the fixing surface of the first waterproof membrane 11 in the measuring jig. The diameter of the through hole in the measuring jig shall be 1.6 mm. The fact that the diameter of the through hole is X mm means that a circular water pressure application surface with a diameter of X mm is set for the first waterproof membrane 11 in the water pressure holding test.

[0065] The waterproof member 10A has water-holding resistance that can withstand a water pressure holding test in which it is exposed to pure water at a water pressure of 1.0 MPa for 30 minutes when, for example, a circular water pressure application surface with a diameter of 1.6 mm is set.

[0066] The waterproof member 10A has water-holding resistance capable of withstanding a water pressure holding test in which it is exposed to soapy water (soap concentration 0.5 wt%) at a water pressure of 0.5 MPa for 10 minutes when a circular water pressure application surface with a diameter of 1.6 mm is set. The waterproof member 10A can exhibit excellent resistance to soapy water.

[0067] At least one main surface of the first waterproof membrane 11 and / or at least one main surface of the second waterproof membrane 12 may be treated with a liquid-repellent coating. A waterproof member 10A having such a configuration has higher waterproofing performance. Furthermore, for example, the resistance of the waterproof member 10A to soapy water can be improved.

[0068] The main surfaces of both of the first waterproof membrane 11 and / or the main surfaces of both of the second waterproof membrane 12 may be treated with a liquid-repellent coating.

[0069] The liquid-repellent treatment can be performed by applying a liquid-repellent solution to at least one main surface of the first waterproof film 11 and / or at least one main surface of the second waterproof film 12, and then drying it. The method of applying the liquid-repellent solution is not particularly limited, and for example, a spray method, spin coating method, dipping method, roll coater method, etc., can be used. The concentration of the liquid-repellent agent in the liquid-repellent solution is preferably 0.1 to 10% by weight, and more preferably 0.5 to 5.0% by weight.

[0070] The liquid repellent is not particularly limited, but a fluorine-based liquid repellent is preferred. The fluorine-based liquid repellent is preferably one or more selected from the group consisting of acrylic polymers having fluorine-containing side chains, urethane polymers having fluorine-containing side chains, and silicone polymers having fluorine-containing side chains. For example, a mixture of a liquid repellent a, which includes a polymer with the compound shown in the following chemical formula (a) as a monomer, and a solvent can be used as the liquid repellent.

[0071] CH2=C(CH3)COOCH2CH2C5F 10 CH2C4F9...(a)

[0072] As a solvent, a mixed solution of 1,1,2,2-tetrafluoroethoxy-1-(2,2,2-trifluoro)ethane (hereinafter referred to as HFE-347pc-f) (manufactured by AGC, AE-3000) and metaxylene hexafluoride (hereinafter referred to as MX-HF) can be used. The mixing ratio, expressed as a volume ratio, is preferably HFE-347pc-f:MX-HF = 3:1.

[0073] Furthermore, commercially available fluorine-based liquid repellents can be used as described above. For example, Daikin's "Unidyne®" series; Shin-Etsu Chemical's X-70-029C; and AGC Seimi Chemical's "SF Coat®" series (e.g., SIF-200) can be used. Additionally, as a silicone-based polymer fluorine-based liquid repellent, Shin-Etsu Chemical's KP-801M is an example.

[0074] For the solvent used in the liquid-repellent solution, a fluorine-based solvent with high affinity for fluorine-based side chains is preferred. Commercially available fluorine-based solvents with high affinity for fluorine-based side chains may be used. Examples of commercially available products include FS Thinner manufactured by Shin-Etsu Chemical Co., Ltd. and Fluorinert manufactured by Sumitomo 3M Co., Ltd. These may be used individually or in mixtures of two or more.

[0075] The drying process after application of the liquid-repellent solution is not particularly limited and may be natural drying (air drying) or heat drying. Heat drying at 40 to 120°C is preferred, and heat drying at 50 to 110°C is more preferred, as it provides excellent breathability after oil adhesion.

[0076] The first waterproof membrane 11 and the second waterproof membrane 12 may be colored. If the first waterproof membrane 11 and the second waterproof membrane 12 are transparent or white, they may be conspicuous when the waterproof member 10A is positioned to cover the opening 51 of the object 50. Therefore, by coloring the first waterproof membrane 11 and the second waterproof membrane 12 according to the color of the object 50 on which they are positioned, a waterproof member 10A that is less conspicuous when positioned on the object 50 can be realized. The first waterproof membrane 11 and the second waterproof membrane 12 may be colored, for example, black. Furthermore, when the design of the object 50 is important, positioning the waterproof member 10A to cover the opening 51 of the object 50 may impair the design. Therefore, by coloring the first waterproof membrane 11 and the second waterproof membrane 12 according to the design of the object 50, the design can be maintained.

[0077] The coloring of the first waterproof membrane 11 and the second waterproof membrane 12 can be achieved, for example, by incorporating a coloring agent into the raw materials contained in the first waterproof membrane 11 and the second waterproof membrane 12. When realizing equipment with a design aesthetic, it is desirable that the coloring agent used has light absorption ability for at least a portion of the wavelength range between 380 nm and 500 nm. In other words, it is desirable that the first waterproof membrane 11 and the second waterproof membrane 12 are colored black, gray, brown, green, yellow, or pink by this coloring agent. Methods for coloring the first waterproof membrane 11 and the second waterproof membrane 12 include a method of coloring by mixing a coloring agent such as pigment or carbon black into the raw materials, and a method of coloring the raw materials after they have been formed into sheets using dyeing or printing techniques. When carbon black is used as the coloring agent, it is possible to improve the strength of the first waterproof membrane 11 and the second waterproof membrane 12, and further improve their waterproofness.

[0078] The adhesive constituting the inner adhesive layer 21 can be any suitable adhesive, as long as it does not impair the effects of the present invention. Such an adhesive is preferably at least one selected from the group consisting of acrylic adhesives, urethane adhesives, and silicone adhesives, and is preferably an acrylic adhesive. The adhesive constituting the inner adhesive layer 21 may also be an acrylic adhesive.

[0079] Below, we will describe acrylic adhesives as a typical example of adhesives that constitute the inner adhesive layer 21.

[0080] Acrylic adhesives are formed from acrylic adhesive compositions. Acrylic adhesives can thus be defined as being formed from acrylic adhesive compositions. This is because acrylic adhesives are formed when acrylic adhesive compositions undergo crosslinking reactions such as heating or ultraviolet irradiation, making it impossible and impractical to directly identify acrylic adhesives by their structure. Therefore, the definition "formed from acrylic adhesive compositions" appropriately identifies acrylic adhesives as a "substance."

[0081] The acrylic adhesive composition preferably comprises an acrylic polymer and a crosslinking agent. The acrylic polymer may be referred to as a so-called base polymer in the field of acrylic adhesives. There may be only one type of acrylic polymer or two or more types.

[0082] The content of acrylic polymer in the acrylic adhesive composition is preferably 60% to 99.9% by weight, more preferably 65% ​​to 99.9% by weight, even more preferably 70% to 99.9% by weight, particularly preferably 75% to 99.9% by weight, and most preferably 80% to 99.9% by weight, based on solid content.

[0083] The weight-average molecular weight of the acrylic polymer is preferably 100,000 to 2,500,000, more preferably 200,000 to 2,000,000, even more preferably 300,000 to 1,800,000, and particularly preferably 400,000 to 1,500,000, in order to better exhibit the effects of the present invention.

[0084] As the acrylic polymer, any suitable acrylic polymer can be used as long as it does not impair the effects of the present invention. Preferably, such an acrylic polymer is formed by polymerization from a composition (M) comprising an alkyl (meth)acrylate (component a) having 4 to 12 carbon atoms in the alkyl group of the alkyl ester portion, and at least one (component b) selected from the group consisting of (meth)acrylate esters and (meth)acrylic acid having an OH group. Component a and component b may each be independent of one type or two or more types.

[0085] Examples of alkyl (meth)acrylate esters having 4 to 12 carbon atoms in the alkyl group of the alkyl ester portion include n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Among these, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate are preferred in terms of being able to better express the effects of the present invention, and more preferably n-butyl acrylate and 2-ethylhexyl acrylate.

[0086] Examples of (meth)acrylic acid esters having an OH group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. Among these, hydroxyethyl (meth)acrylate and hydroxybutyl (meth)acrylate are preferred, and hydroxyethyl acrylate is preferred, in terms of being able to better express the effects of the present invention.

[0087] As the (meth)acrylic acid, acrylic acid is preferred in that it can better exhibit the effects of the present invention.

[0088] Composition (M) may contain copolymerizable monomers other than components a and b. The copolymerizable monomer may be one type or two or more types. Examples of such copolymerizable monomers include carboxyl group-containing monomers such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and their acid anhydrides (e.g., acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride) (except (meth)acrylic acid); amide group-containing monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide; amino group-containing monomers such as (meth)acrylate aminoethyl, (meth)acrylate dimethylaminoethyl, and (meth)acrylate t-butylaminoethyl; epoxy group-containing monomers such as (meth)acrylate glycidyl and (meth)acrylate methylglycidyl; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N - Heterocyclic monomers such as vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole; sulfonic acid group-containing monomers such as sodium vinylsulfonate; phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; cyclopentyl (meth (meth)acrylic acid esters having alicyclic hydrocarbon groups such as acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; aromatic ring-containing (meth)acrylates such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxybenzyl (meth)acrylate (e.g., m-phenoxybenzyl (meth)acrylate), thiophenoxybenzyl (meth)acrylate, and benzylbenzyl (meth)acrylate;Examples include (meth)acrylate alkoxyalkyl esters such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins and dienes such as ethylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

[0089] Polyfunctional monomers can also be used as copolymerizable monomers. A polyfunctional monomer is a monomer having two or more ethylenically unsaturated groups in one molecule. Any suitable ethylenically unsaturated group can be used as the ethylenically unsaturated group, as long as it does not impair the effects of the present invention. Examples of such ethylenically unsaturated groups include radical polymerizable functional groups such as vinyl groups, propenyl groups, isopropenyl groups, vinyl ether groups (vinyloxy groups), and allyl ether groups (allyloxy groups). Examples of polyfunctional monomers include hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, vinyl(meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate. Such polyfunctional monomers may be present in single-component form or in two or more forms.

[0090] The content of the alkyl (meth)acrylate (component a) in which the alkyl group of the alkyl ester portion has 4 to 12 carbon atoms is preferably 30% by weight or more, more preferably 35% to 99% by weight, even more preferably 40% to 98% by weight, and particularly preferably 50% to 95% by weight, relative to the total amount (100% by weight) of the monomer components constituting the acrylic polymer, in order to better express the effects of the present invention.

[0091] The content of at least one (component b) selected from the group consisting of (meth)acrylic acid esters having an OH group and (meth)acrylic acid is preferably 1% by weight or more, more preferably 1% to 30% by weight, even more preferably 2% to 20% by weight, and particularly preferably 3% to 10% by weight, relative to the total amount of monomer components constituting the acrylic polymer (100% by weight), in order to better express the effects of the present invention.

[0092] Composition (M) may contain any other suitable components, as long as they do not impair the effects of the present invention. Examples of such other components include polymerization initiators, chain transfer agents, and solvents. The content of these other components may be any suitable amount, as long as they do not impair the effects of the present invention.

[0093] Depending on the type of polymerization reaction, the polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator (photoinitiator). There may be only one polymerization initiator or two or more.

[0094] Thermal polymerization initiators can preferably be used when obtaining acrylic polymers by solution polymerization. Examples of such thermal polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid)dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, and 2,2'-azobis[2-(5-methyl-2-imidazoline-2-yl)pro Azo initiators such as pan-dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethylene isobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl) peroxydicarbonate, Examples include peroxide initiators such as di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butylhydroperoxide, and hydrogen peroxide; redox initiators combining peroxides with reducing agents, such as combinations of persulfates and sodium bisulfite, and combinations of peroxides and sodium ascorbate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0095] Photopolymerization initiators can preferably be used when obtaining acrylic polymers by active energy ray polymerization. Examples of photopolymerization initiators include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators.

[0096] Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Examples of photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzyl-based photopolymerization initiators include benzyl. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of ketal-based photopolymerization initiators include benzyldimethylketal. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0097] The amount of polymerization initiator used can be set to any appropriate amount, as long as it does not impair the effects of the present invention.

[0098] The acrylic adhesive composition may contain a crosslinking agent. By using a crosslinking agent, the cohesive force of the acrylic adhesive can be improved, and the effects of the present invention can be further exhibited. There may be only one type of crosslinking agent, or there may be two or more types.

[0099] Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, and peroxides. Preferably, the crosslinking agent is at least one selected from the group consisting of isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and peroxides (component c).

[0100] The isocyanate crosslinking agent can be a compound having two or more isocyanate groups (including isocyanate-regenerating polar groups in which the isocyanate groups are temporarily protected by a blocking agent or quantification, etc.) in one molecule. Examples of isocyanate crosslinking agents include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0101] Examples of isocyanate crosslinking agents include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl isocyanate; isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate derivatives of hexamethylene diisocyanate (e.g., manufactured by Tosoh Corporation, trade name: Coronate HX); xyl Examples include trimethylolpropane adducts of reylene diisocyanate (e.g., Mitsui Chemicals, trade name: Takenate D110N), trimethylolpropane adducts of xylylene diisocyanate (e.g., Mitsui Chemicals, trade name: Takenate D120N), trimethylolpropane adducts of isophorone diisocyanate (e.g., Mitsui Chemicals, trade name: Takenate D140N), trimethylolpropane adducts of hexamethylene diisocyanate (e.g., Mitsui Chemicals, trade name: Takenate D160N), trimethylolpropane adducts of tolylene diisocyanate (e.g., Mitsui Chemicals, trade name: Takenate D101E); polyether polyisocyanates, polyester polyisocyanates, and adducts thereof with various polyols; and polyfunctionalized polyisocyanates with isocyanurate bonds, biuret bonds, allophanate bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferred because they can achieve a good balance between deformability and cohesiveness.

[0102] As epoxy crosslinking agents, polyfunctional epoxy compounds having two or more epoxy groups in one molecule can be used. Examples of epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-m-xylenediline, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polyglycidyl ether. Examples of epoxy crosslinking agents include tel, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate ester, diglycidyl o-phthalate ester, triglycidyl-tris(2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Examples of commercially available epoxy crosslinking agents include the trade names "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company.

[0103] Examples of peroxides include dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butyl peroxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy Examples include neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexyl peroxy)cyclohexane, 1,1-di(t-butyl peroxy)cyclohexane, t-butyl peroxy-2-ethylhexyl carbonate, t-amyl peroxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxy-2-hexanoate, t-butyl peroxypivalate, and t-hexyl peroxypivalate. Examples of commercially available peroxides include the "Nipper BMT" series and the "Nipper BW" series manufactured by Nippon Oil & Fats Co., Ltd.

[0104] The amount of crosslinking agent in the acrylic adhesive composition can be any appropriate amount, as long as it does not impair the effects of the present invention. For example, in order to better express the effects of the present invention, the amount is preferably 0.01 to 20 parts by weight, more preferably 0.01 to 18 parts by weight, even more preferably 0.01 to 15 parts by weight, and particularly preferably 0.05 to 10 parts by weight, relative to the solid content (100 parts by weight) of the acrylic polymer.

[0105] The acrylic adhesive composition may contain any other suitable components as long as they do not impair the effects of the present invention. Examples of such other components include polymer components other than acrylic polymers, crosslinking accelerators, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), anti-aging agents, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foils, UV absorbers, antioxidants, light stabilizers, nucleating agents, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts, and the like.

[0106] In this embodiment, the adhesive constituting the inner adhesive layer 21 includes a tackifier. Examples of tackifiers include terpene-based tackifiers, acrylic oligomers, and hydrocarbon-based tackifiers. The tackifier may include at least one selected from the group consisting of terpene-based tackifiers and acrylic oligomers. Such tackifiers can be used individually or in combination of two or more.

[0107] Examples of terpene-based tackifiers include terpene resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers; and modified terpene resins obtained by modifying these terpene resins (phenol modification, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.). An example of the above-mentioned modified terpene resin is terpene phenol resin.

[0108] Terpene phenol resins refer to polymers containing terpene and phenol residues, and the concept encompasses both copolymers of terpenes and phenol compounds (terpene-phenol copolymer resins) and homopolymers or copolymers of terpenes modified with phenol (phenol-modified terpene resins). Specific examples of terpenes that constitute such terpene phenol resins include monoterpenes such as α-pinene, β-pinene, and limonene (including d-isomers, l-isomers, and d / l-isomers (dipentene)). Hydrogenated terpene phenol resins refer to hydrogenated terpene phenol resins having a structure obtained by hydrogenating such terpene phenol resins. They are sometimes also called hydrogenated terpene phenol resins.

[0109] Examples of hydrocarbon-based tackifying resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, hydrogenated versions thereof (e.g., alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins), various modified versions thereof (e.g., maleic anhydride modified versions), coumarone resins, coumarone indene resins, and other hydrocarbon-based resins.

[0110] The acrylic oligomer preferably has a Tg of about 0°C to about 300°C, more preferably about 20°C to about 300°C, and more preferably about 40°C to about 300°C. By having a Tg within the above range, the adhesive strength can be suitably improved. In some preferred embodiments, from the viewpoint of adhesive cohesiveness, the Tg of the acrylic oligomer is about 30°C or higher, more preferably about 50°C or higher (for example, about 60°C or higher), and from the viewpoint of adhesion, it is preferably about 200°C or lower, more preferably about 150°C or lower, and even more preferably about 100°C or lower (for example, approximately 80°C or lower).

[0111] In this specification, Tg of an acrylic oligomer refers to the Tg determined by Fox's formula based on the composition of the monomer components. Fox's formula is a relationship between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below: 1 / Tg = Σ(Wi / Tgi) In Fox's formula above, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (weight-based copolymerization ratio), and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K). The Tg of the homopolymer used to calculate Tg is the same as described for the homopolymer Tg of the monomers of the acrylic polymer.

[0112] The weight-average molecular weight (Mw) of the acrylic oligomer is typically about 1,000 or more and less than 30,000, preferably about 1,500 or more and less than 20,000, and more preferably about 2,000 or more and less than 10,000. Having Mw within this range is preferable because it provides good adhesion. In some preferred embodiments, the Mw of the acrylic oligomer is about 2,500 or more (e.g., about 3,000 or more), and from the viewpoint of adhesion, it is preferably about 7,000 or less, more preferably about 5,000 or less (e.g., about 4,500 or less, typically about 4,000 or less). The Mw of the acrylic oligomer can be measured by gel permeation chromatography (GPC) and determined as a value equivalent to standard polystyrene. Specifically, it is measured using a Tosoh HPLC-8020 with two TSKgelGMH-H(20) columns at a flow rate of about 0.5 mL / min in tetrahydrofuran solvent.

[0113] Examples of monomers that make up acrylic oligomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate. Examples of (meth)acrylates include alkyl (meth)acrylates such as acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate; esters of (meth)acrylic acid with alicyclic alcohols (alicyclic hydrocarbon group-containing (meth)acrylates) such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate; and (meth)acrylates obtained from terpene compound derivative alcohols. Such (meth)acrylates can be used individually or in combination of two or more.

[0114] As acrylic oligomers, it is preferable from the viewpoint of further improving the adhesion of the inner adhesive layer 21 that the monomer units include acrylic monomers having a relatively bulky structure, such as alkyl(meth)acrylates having a branched alkyl group structure, like isobutyl(meth)acrylate and t-butyl(meth)acrylate; esters of (meth)acrylic acid and alicyclic alcohols (alicyclic hydrocarbon group-containing (meth)acrylates), like cyclohexyl(meth)acrylate, isobornyl(meth)acrylate, and dicyclopentanyl(meth)acrylate; aryl(meth)acrylates having a cyclic structure, like phenyl(meth)acrylate and benzyl(meth)acrylate. Furthermore, when ultraviolet light is used during the synthesis of acrylic oligomers or during the preparation of the inner adhesive layer 21, saturated bonds are preferred in that they are less likely to inhibit polymerization. Alkyl (meth)acrylates with branched alkyl groups, or esters with alicyclic alcohols (alicyclic hydrocarbon group-containing (meth)acrylates) can be suitably used as monomers constituting the acrylic oligomers. Note that the above-mentioned branched alkyl (meth)acrylates, alicyclic hydrocarbon group (meth)acrylates, and aryl (meth)acrylates all correspond to (meth)acrylate monomers in the technology disclosed herein. The alicyclic hydrocarbon group may be saturated or unsaturated.

[0115] The proportion of (meth)acrylate monomers (e.g., alicyclic hydrocarbon group-containing (meth)acrylates) in the total monomer components constituting the acrylic oligomer is typically greater than 50% by weight, preferably 60% by weight or more, and more preferably 70% by weight or more (e.g., 80% by weight or more, and even more than 90% by weight or more). In some preferred embodiments, the acrylic oligomer has a monomer composition consisting substantially only of (meth)acrylate monomers.

[0116] In addition to the (meth)acrylate monomers mentioned above, functional group-containing monomers can be used as constituent monomer components of acrylic oligomers. Preferred examples of the functional group-containing monomers include monomers having nitrogen atom-containing rings (typically nitrogen atom-containing heterocycles) such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; amino group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylate; amide group-containing monomers such as N,N-diethyl (meth)acrylamide; carboxyl group-containing monomers such as AA and MAA; and hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate. These functional group-containing monomers can be used individually or in combination of two or more. Among these, carboxyl group-containing monomers are preferred, and AA is particularly preferred.

[0117] When all monomer components constituting an acrylic oligomer include functional group-containing monomers, the proportion of functional group-containing monomers (for example, carboxyl group-containing monomers such as AA) in the total monomer components is appropriately approximately 1% by weight or more, preferably 2% by weight or more, more preferably 3% by weight or more, and appropriately approximately 15% by weight or less, preferably 10% by weight or less, and more preferably 7% by weight or less.

[0118] Acrylic oligomers can be formed by polymerizing their constituent monomer components. The polymerization method and polymerization mode are not particularly limited, and various conventionally known polymerization methods (e.g., solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, radiation polymerization, etc.) can be employed in appropriate manner. The types of polymerization initiators that can be used as needed (e.g., azo polymerization initiators such as AIBN) are generally as exemplified in the synthesis of acrylic polymers, and the amount of polymerization initiator and the amount of chain transfer agent such as n-dodecyl mercaptan used optionally are appropriately set based on common technical knowledge to achieve the desired molecular weight, so a detailed explanation is omitted here.

[0119] From the above viewpoint, suitable acrylic oligomers include, for example, homopolymers of dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclopentanyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), and 1-adamantyl acrylate (ADA), as well as copolymers of CHMA and isobutyl methacrylate (IBMA), copolymers of CHMA and IBXMA, copolymers of CHMA and acryloylmorpholine (ACMO), copolymers of CHMA and diethylacrylamide (DEAA), copolymers of CHMA and AA, copolymers of ADA and methyl methacrylate (MMA), copolymers of DCPMA and IBXMA, copolymers of DCPMA and MMA, and the like.

[0120] When the inner adhesive layer 21 contains an acrylic oligomer, the amount is not particularly limited, but it is appropriate to have at least 0.1 parts by weight (for example, 1 part by weight or more) per 100 parts by weight of the acrylic polymer. From the viewpoint of better exhibiting the effects of the acrylic oligomer, in some embodiments, the amount of the acrylic oligomer is approximately 3 parts by weight or more, may be approximately 5 parts by weight or more, may be approximately 10 parts by weight or more, or may be approximately 12 parts by weight or more. Furthermore, from the viewpoint of compatibility with the acrylic polymer, it is appropriate to have an amount of the acrylic oligomer less than 50 parts by weight (for example, less than 40 parts by weight) per 100 parts by weight of the acrylic polymer, preferably less than 30 parts by weight, more preferably approximately 25 parts by weight or less, and even more preferably approximately 20 parts by weight or less. In some embodiments, the amount of the acrylic oligomer may be 10 parts by weight or less, may be 5 parts by weight or less, or may be 1 part by weight or less (for example, less than 1 part by weight) per 100 parts by weight of the acrylic polymer. The inner adhesive layer 21 may be substantially free of acrylic oligomers.

[0121] In some embodiments, the inner adhesive layer 21 may contain one or more of the above-mentioned tackifier resins and one or more of acrylic oligomers. The content ratio C of the acrylic oligomer in the inner adhesive layer 21 O with respect to the content ratio C of the tackifier resin in [wt%] T [wt%] of the ratio (C T / C O ) is not particularly limited. In some embodiments, the above (C T / C O ) is preferably, for example, 0.1 or more on a weight basis, preferably 0.5 or more, and may be 1 or more (e.g., more than 1), 2 or more, 3 or more, or 4 or more. The larger the above ratio (C T / C O ), the easier it is to obtain the effect of using the tackifier resin. Also, in some embodiments, the above (C T / C O ) is preferably, for example, 10 or less on a weight basis, preferably 8 or less, and may be 6 or less, or 5 or less. Thereby, the effect of using the acrylic oligomer can be preferably exhibited.

[0122] The total amount (total) of the acrylic polymer and the tackifier in the inner adhesive layer 21 is appropriately set so that the effects of the technology disclosed herein are exhibited, and is not limited to a specific range. In some preferred embodiments, the total amount (total) of the acrylic polymer and the tackifier in the inner adhesive layer 21 preferably occupies more than 50 wt% of the inner adhesive layer 21 from the viewpoint of preferably exhibiting the effects of the technology disclosed herein, preferably approximately 70 wt% or more, more preferably approximately 90 wt% or more, still more preferably 95 wt% or more (e.g., 95 wt% or more and 100 wt% or less or less than 100 wt%), and may be 98 wt% or more.

[0123] The method for manufacturing the first waterproof film 11 and the second waterproof film 12 is not particularly limited and can be appropriately selected according to the purpose.

[0124] For example, if the first waterproof membrane 11 and the second waterproof membrane 12 are PTFE stretched porous membranes, the PTFE stretched porous membrane is usually manufactured by stretching a paste extruded or cast membrane containing PTFE particles.

[0125] For example, if the first waterproof membrane 11 and the second waterproof membrane 12 are silicone non-porous membranes, the silicone non-porous membrane can be manufactured by, for example, extruding a raw material solution into a thin layer onto a releaseable substrate using an extrusion means such as a die, or by pouring the raw material solution onto a releaseable substrate and then forming a thin film with an applicator, wire bar, or knife coater.

[0126] The configuration of the waterproofing member 10 according to the first embodiment is not limited to the examples shown in Figures 1A to 1B. Hereinafter, modifications of the waterproofing member 10 according to the first embodiment will be described.

[0127] (Modification 1) A modification 1 of the waterproof member 10 according to the first embodiment is shown in Figures 2A to 2B. The waterproof member 10B of Modification 1 shown in Figures 2A to 2B further comprises a first outer adhesive layer 31 bonded to the first main surface 11a of the first waterproof membrane 11. As shown in Figure 2C, the waterproof member 10B is used by being fixed to an object 50 by the first outer adhesive layer 31 so as to close the opening 51 of the object 50 having an opening surface 51s in which the opening 51 is formed. In the following, elements of the waterproof member 10B that are common to the waterproof member 10A will be given the same reference numerals and their descriptions may be omitted.

[0128] In the waterproof member 10B, the storage modulus G' of the first outer adhesive layer 31 at 25°C is equal to or greater than the storage modulus G' of the inner adhesive layer 21 at 25°C. With this configuration, the first outer adhesive layer 31 bonded to the first main surface 11a of the first waterproof membrane 11 can suppress the occurrence of wrinkles and creases in the first waterproof membrane 11. Wrinkles and creases not only degrade the appearance of the waterproof membrane, but can also reduce the sound permeability of the waterproof membrane over time.

[0129] The storage modulus G' of the first outer adhesive layer 31 at 25°C may be greater than the storage modulus G' of the inner adhesive layer 21 at 25°C. With this configuration, the occurrence of wrinkles and creases in the first waterproof film 11 is further suppressed.

[0130] In the waterproof member 10B, the storage modulus G' of the first outer adhesive layer 31 at 25°C is, for example, 0.20 MPa or more.

[0131] In the waterproof member 10B, the lower limit of the storage modulus G' of the first outer adhesive layer 31 at 25°C may be 0.21 MPa or more, 0.22 MPa or more, 0.23 MPa or more, or even 0.24 MPa or more. The upper limit of the storage modulus G' of the first outer adhesive layer 31 at 25°C is, for example, 0.32 MPa or less. The upper limit of the storage modulus G' of the first outer adhesive layer 31 at 25°C may be 0.31 MPa or less, 0.30 MPa or less, 0.29 MPa or less, or even 0.28 MPa or less.

[0132] The storage modulus G' of the first outer adhesive layer 31 at 25°C can be measured by the same method as described above for the storage modulus G' of the inner adhesive layer 21 at 25°C.

[0133] In the waterproof member 10B, the thickness of the first outer adhesive layer 31 may be equal to or greater than the thickness of the inner adhesive layer 21. With such a configuration, the effect of suppressing the deterioration of sound transmission characteristics is easily achieved.

[0134] In the waterproof member 10B, the thickness of the first outer adhesive layer 31 may be greater than the thickness of the inner adhesive layer 21.

[0135] In the waterproof member 10B, the thickness of the first outer adhesive layer 31 is, for example, 50 μm or more and 150 μm or less. By having the thickness of the first outer adhesive layer 31 within the above range, the effect of suppressing the deterioration of sound transmission characteristics is easily achieved.

[0136] The thickness of the first outer adhesive layer 31 can be measured by the same method as described above for the thickness of the first waterproof membrane 11.

[0137] As the adhesive constituting the first outer adhesive layer 31, the adhesive described above for the adhesive constituting the inner adhesive layer 21 can be used.

[0138] (Modification 2) A modification 2 of the waterproof member 10 according to the first embodiment is shown in Figures 3A to 3B. The waterproof member 10C of modification 2 shown in Figures 3A to 3B further comprises a second outer adhesive layer 32 bonded to the second main surface 12b of the second waterproof membrane 12. As shown in Figure 3C, the waterproof member 10C is used by being fixed to an object 60 by the first outer adhesive layer 31 so as to close an opening 56 of an object 60 having an opening surface 61s in which an opening 61 is formed. The waterproof member 10C is fixed to a substrate 63 on which a microphone element 62 is arranged by the second outer adhesive layer 32. In the following, elements of the waterproof member 10C that are common with waterproof members 10A and 10B will be given the same reference numerals and their descriptions may be omitted.

[0139] In the waterproof member 10C, the storage modulus G' of the first outer adhesive layer 31 at 25°C and the storage modulus G' of the second outer adhesive layer 32 at 25°C are greater than the storage modulus G' of the inner adhesive layer 21 at 25°C. With this configuration, the first outer adhesive layer 31 bonded to the first main surface 11a of the first waterproof membrane 11 makes it easier to prevent wrinkles and creases from forming in the first waterproof membrane 11, and the second outer adhesive layer 32 bonded to the second main surface 12b of the second waterproof membrane 12 makes it easier to prevent wrinkles and creases from forming in the second waterproof membrane 12. As a result, in addition to preventing deterioration of the appearance of the first waterproof membrane 11 and the second waterproof membrane 12, the deterioration of the sound transmission characteristics of the first waterproof membrane 11 and the second waterproof membrane 12 over time can be suppressed.

[0140] In the waterproof member 10C, the storage modulus G' of the first outer adhesive layer 31 at 25°C and the storage modulus G' of the second outer adhesive layer 32 at 25°C may be the same or different.

[0141] In the waterproof member 10C, the storage modulus G' of the first outer adhesive layer 31 at 25°C and the storage modulus G' of the second outer adhesive layer 32 at 25°C are, for example, 0.20 MPa or higher.

[0142] In the waterproof member 10C, the lower limit of the storage modulus G' of the first outer adhesive layer 31 at 25°C may be 0.21 MPa or more, 0.22 MPa or more, 0.23 MPa or more, or even 0.24 MPa or more. The upper limit of the storage modulus G' of the first outer adhesive layer 31 at 25°C is, for example, 0.32 MPa or less. The upper limit of the storage modulus G' of the first outer adhesive layer 31 at 25°C may be 0.31 MPa or less, 0.30 MPa or less, 0.29 MPa or less, or even 0.28 MPa or less.

[0143] In the waterproof member 10C, the lower limit of the storage modulus G' of the second outer adhesive layer 32 at 25°C may be 0.21 MPa or more, 0.22 MPa or more, 0.23 MPa or more, or even 0.24 MPa or more. The upper limit of the storage modulus G' of the second outer adhesive layer 32 at 25°C is, for example, 0.32 MPa or less. The upper limit of the storage modulus G' of the second outer adhesive layer 32 at 25°C may be 0.31 MPa or less, 0.30 MPa or less, 0.29 MPa or less, or even 0.28 MPa or less.

[0144] The storage modulus G' of the first outer adhesive layer 31 at 25°C and the storage modulus G' of the second outer adhesive layer 32 at 25°C can be measured by the same method as described above for the storage modulus G' of the inner adhesive layer 21 at 25°C.

[0145] In the waterproof member 10C, at least one selected from the group consisting of the thickness of the first outer adhesive layer 31 and the thickness of the second outer adhesive layer 32 may be equal to or greater than the thickness of the inner adhesive layer 21. With such a configuration, the effect of suppressing the deterioration of sound transmission characteristics is easily achieved.

[0146] In the waterproof member 10C, at least one selected from the group consisting of the thickness of the first outer adhesive layer 31 and the thickness of the second outer adhesive layer 32 may be greater than the thickness of the inner adhesive layer 21.

[0147] In the waterproof member 10C, the thickness of the first outer adhesive layer 31 and the thickness of the second outer adhesive layer 32 may be the same or different.

[0148] In the waterproof member 10C, the thickness of the first outer adhesive layer 31 and the thickness of the second outer adhesive layer 32 are, for example, 50 μm or more and 150 μm or less. By having the thickness of the first outer adhesive layer 31 and the thickness of the second outer adhesive layer 32 within the above range, the effect of suppressing the deterioration of sound transmission characteristics is easily achieved.

[0149] The thickness of the first outer adhesive layer 31 and the thickness of the second outer adhesive layer 32 can be measured by the same method as described above for the thickness of the first waterproof membrane 11.

[0150] As the adhesive constituting the second outer adhesive layer 32, the adhesive described above for the adhesive constituting the inner adhesive layer 21 can be used.

[0151] (Second Embodiment) [Electronic Device] The waterproof member 10 according to the first embodiment can also be applied to electronic devices having an audio function. Embodiments of electronic devices in which the waterproof member 10 is used will be described below.

[0152] An example of the electronic device 300 according to the second embodiment is shown in Figure 4. The electronic device 300 shown in Figure 4 is a smartphone 300A. The smartphone 300A includes the waterproof member 10 and housing 301 described above.

[0153] Inside the housing 301 of the smartphone 300A, there is an audio converter that converts electrical signals into sound. The audio converter (audio conversion unit) is, for example, a speaker or a microphone. The audio converter may also be a microphone. The housing 301 is provided with openings 302a and 302b, which are external sound vents.

[0154] In the smartphone 300A, a first waterproof member 10 is positioned on the housing 301 so as to cover the opening 302a. A second waterproof member 10 is also positioned on the housing 301 so as to cover the opening 302b. For both waterproof members 10, the first main surface 11a of the first waterproof membrane 11 faces the outside through the opening 302a or 302b.

[0155] Furthermore, the first and second waterproof members 10 are each fixed to an audio converter housed inside the housing 301 (not shown). The other main surface of both waterproof members 10 is in contact with the audio converter.

[0156] The electronic device 300 equipped with the waterproof member 10 is not limited to a smartphone 300A. Examples of electronic devices 300 include wearable devices such as smartwatches and wristbands; various cameras including action cameras and security cameras; communication devices such as mobile phones and smartphones; virtual reality (VR) devices; augmented reality (AR) devices; sensor devices, etc. The electronic device may also be a miniature product such as a MEMS.

[0157] (Third Embodiment) [Component Supply Assembly] The waterproof member 10 can be supplied, for example, by a component supply assembly. An example of a component supply assembly, which is a method of supplying the waterproof member 10, is shown in Figure 5. The component supply assembly 400 (400A) in Figure 5 comprises a waterproof member 10 (10B) that is arranged to close the opening of an object having an opening surface in which an opening is formed, and a base sheet 401 on which the waterproof member 10 (10B) is placed. The component supply assembly 400A comprises the waterproof member 10B shown in Figures 2A to 2B as the waterproof member 10.

[0158] The waterproof member 10 (10B) is placed on the base sheet 401 via the first outer adhesive layer 31. The member supply assembly 400 (400A) allows for efficient supply of the waterproof member 10 for, for example, the process of placing it on the surface of an object.

[0159] The waterproof member 10 may be placed on the base sheet 401 via an adhesive layer provided on the placement surface of the waterproof member 10 on the base sheet 401. The adhesive layer on the placement surface is preferably weakly tacky.

[0160] Although not shown in the diagram, a plurality of waterproofing members 10 may be arranged on the surface of the base sheet 401.

[0161] Examples of materials constituting the base sheet 401 include paper, metal, resin, and composite materials thereof. Examples of metals include stainless steel and aluminum. Examples of resins include polyester such as PET, and polyolefins such as PE and PP. However, the materials constituting the base sheet 401 are not limited to the above examples. The base sheet 401 may be in the form of a single sheet or a strip. If the base sheet 401 is in the form of a strip, the component supply assembly 400 may be wound to form a wound body.

[0162] Examples of objects on which the waterproof member 10 is placed include the housings of electronic devices and the housings of vehicle electrical components. The waterproof member 10 can be placed on the outer and / or inner surfaces of the housing. In this case, the opening may be a ventilation opening and / or sound vent provided in the housing. Examples of electronic devices include wearable devices such as smartwatches and wristbands; various cameras including action cameras and security cameras; information and communication devices such as mobile phones, smartphones and tablets; virtual reality (VR) devices; augmented reality (AR) devices; and sensor devices. Examples of vehicle electrical components include lamps and ECUs. However, the objects are not limited to the above examples.

[0163] A modified example of the component supply assembly 400 of this embodiment is shown in Figure 6. The component supply assembly 400 (400B) in Figure 6 includes the waterproof member 10C shown in Figures 3A to 3B as the waterproof member 10. The component supply assembly 400B further includes a release liner 402, and the waterproof member 10C and the release liner 402 are joined via a second outer adhesive layer 32. Except for these, the component supply assembly 400B has the same configuration as the component supply assembly 400A in Figure 5.

[0164] The peel-off liner 402 has tabs that protrude outward from the outer circumference of the first waterproof membrane 11 and the second waterproof membrane 12 when viewed perpendicular to the main surfaces of the first waterproof membrane 11 and the second waterproof membrane 12. The waterproof member 10C can be handled and placed on the surface of an object by gripping the tabs. The peel-off liner 402 is usually removed when the waterproof member 10C is used. Examples of materials constituting the peel-off liner 402 include polyolefins such as PE and PP, polyesters such as PET, silicone resins, polycarbonates, polyimides, polyamide-imides, polyphenylene sulfide, polyetheretherketone (PEEK), polyvinyl chloride, fluororesins, and metals such as aluminum and stainless steel. Examples of fluororesins include PTFE, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE). However, the materials constituting the peel-off liner 402 are not limited to the above examples.

[0165] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the examples shown below.

[0166] [Preparation of Waterproof Membrane] (Waterproof Membrane α) A PTFE dispersion (PTFE powder concentration of 40% by mass, average particle size of PTFE powder of 0.2 μm, containing 6 parts by mass of nonionic surfactant per 100 parts by mass of PTFE) was prepared by adding 1 part by mass of fluorine-based surfactant (DIC Corporation, Megafac F-142D) per 100 parts by mass of PTFE. Next, a long polyimide film (thickness 125 μm) was immersed in the PTFE dispersion and then removed to form a coating film of PTFE dispersion on the film. At this time, the thickness of the coating film was set to 20 μm using a measuring bar. Next, the coating film was heated at 100°C for 1 minute, followed by 390°C for 1 minute to evaporate and remove the water contained in the dispersion, and to bind the remaining PTFE particles together to obtain a PTFE film. After repeating the above immersion and heating process two more times, the PTFE film (25 μm thick) was peeled off the polyimide film. Next, the PTFE film was rolled in the MD direction at a rolling ratio of 2.5 times. The rolled PTFE film was stretched in the TD direction at a stretching ratio of 2.0 times using a tenter. The roll setting temperature in the roll rolling machine was 170°C. The stretching temperature was 170°C. In this way, a stretched porous PTFE film was obtained.

[0167] Next, the obtained PTFE stretched porous membrane was subjected to an oil-repellent treatment. The oil-repellent treatment was carried out by spraying an oil-repellent agent solution onto the PTFE stretched porous membrane and drying it. As the oil-repellent agent, the "Unidyne®" series manufactured by Daikin Corporation, which is a fluorine-based oil-repellent agent, was used. The PTFE stretched porous membrane with the oil-repellent treatment obtained in this way was designated as waterproof membrane α.

[0168] (Waterproof membrane β) A PTFE stretched porous membrane was obtained using the same method as waterproof membrane α, except that the stretching ratio in the TD direction was changed to 2.5 times. The obtained PTFE stretched porous membrane was designated as waterproof membrane β. Waterproof membrane β was not treated with an oil-repellent finish.

[0169] (Waterproof membrane γ) As waterproof membrane γ, we used a porous membrane made of ultra-high molecular weight polyethylene (PE) manufactured by Teijin Corporation (Milime®, pore size: 60 nm, thickness: 10 μm).

[0170] (Waterproof membrane δ) A polyester (PET) film (MYLAR CS02, thickness: 1.95 μm) manufactured by DuPont was used as the waterproof membrane δ.

[0171] [Preparation of Adhesive Sheet] (Adhesive Sheet A1) As an adhesive composition, an acrylic adhesive composition described in paragraph

[0158] of Japanese Patent Application Publication No. 2018-87334 was prepared. Specifically, 70 parts by weight of n-butyl acrylate (BA), 30 parts by weight of 2-ethylhexyl acrylate (2-EHA), 3 parts by weight of acrylic acid (AA), 0.05 parts by weight of 4-hydroxybutyl acrylate (4-HBA), and 0.08 parts by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator were added to toluene solvent. Then, solution polymerization was carried out at 68°C for 8 hours to obtain an acrylic polymer solution. The weight-average molecular weight of the acrylic polymer was 440,000. The acrylic polymer solution obtained in this way was referred to as "Acrylic Polymer Solution (A)". To the acrylic polymer solution (A), polymerized rosin pentaerythritol ester resin (Arakawa Chemical Industries, Ltd., Pencel D125, softening point: 125°C) was added in an amount of 30 parts by weight per 100 parts by weight of the acrylic polymer in the solution. Furthermore, an isocyanate crosslinking agent (Nippon Polyurethane Industries, Ltd., Coronate L) was added in an amount of 2 parts by weight per 100 parts by weight of the acrylic polymer in the solution. In this way, an acrylic adhesive composition was prepared.

[0172] The above acrylic adhesive composition was applied to both main surfaces of a 12 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 50 μm thick double-sided tape with a substrate having a 19 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as adhesive sheet A1.

[0173] (Adhesive Sheet A2) As the adhesive composition, the acrylic adhesive composition (A) prepared in the production of adhesive sheet A1 was used. The acrylic adhesive composition (A) was applied to both main surfaces of a 25 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 100 μm thick double-sided tape with a substrate having an adhesive layer of 37.5 μm thickness on both sides. The obtained double-sided tape with a substrate was designated as adhesive sheet A2.

[0174] (Adhesive Sheet B) As an adhesive composition, an acrylic adhesive composition according to Example 4 described in paragraph

[0109] of Japanese Patent Application Publication No. 2015-163690 was prepared. Specifically, 100 parts of n-butyl acrylate (BA), 5 parts of vinyl acetate (VAc), 3 parts of acrylic acid (AA), 0.1 parts of 2-hydroxyethyl acrylate (HEA), 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and toluene as a polymerization solvent were charged into a reaction vessel equipped with a stirrer, thermometer, nitrogen gas introduction tube, reflux condenser, and dropping funnel, and solution polymerization was carried out at 60°C for 6 hours to obtain a toluene solution of acrylic polymer A. The Mw of this acrylic polymer A is 55 × 10 4 The following was done: To 100 parts of acrylic polymer A, 10 parts of rosin resin A (Harima Chemicals, Haritack PCJ, softening point 118-128°C), 10 parts of rosin resin B (Harima Chemicals, Haritack SE10, softening point 75-85°C), 5 parts of rosin resin C (Guangxi Wuzhou Rissei Forestry Chemical Co., Ltd., M-HDR), and 15 parts of terpene phenol resin A (Sumitomo Bakelite, Sumilite Resin PR-12603N) were added as tackifying resins, and 2 parts of isocyanate crosslinking agent (Nippon Polyurethane Industry Co., Ltd., Coronate L) were added as a crosslinking agent to prepare an acrylic adhesive composition.

[0175] The above acrylic adhesive composition was applied to both main surfaces of a 12 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 100 μm thick double-sided tape with a substrate, having a 44 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as adhesive sheet B.

[0176] (Adhesive Sheet C1) As an adhesive composition, an adhesive composition according to Example 2 described in paragraph

[0102] of Japanese Patent No. 6113889 was prepared. Specifically, 95 parts of n-butyl acrylate (BA) and 5 parts of acrylic acid (AA) as monomer components, and 233 parts of ethyl acetate as a polymerization solvent were charged into a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, reflux condenser, and dropping funnel, and the mixture was stirred for 2 hours while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, 0.2 parts of 2,2'-azobisisobutyronitrile was added as a polymerization initiator, and solution polymerization was carried out at 60°C for 8 hours to obtain a solution of acrylic polymer. The Mw of this acrylic polymer was approximately 70 × 10⁻⁶ 4 The above acrylic polymer solution was prepared by adding 30 parts of terpene phenol resin (Yasuhara Chemical Co., Ltd., YS Polystar T-115, softening point: approximately 115°C, hydroxyl value: 30-60 mg KOH / g) as a tackifying resin, 2 parts of isocyanate crosslinking agent (Nippon Polyurethane Industry Co., Ltd., Coronate L, a 75% ethyl acetate solution of trimethylolpropane / tolylene diisocyanate trimer adduct) and 0.01 parts of epoxy crosslinking agent (Mitsubishi Gas Chemical Co., Ltd., TETRAD-C, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) as crosslinking agents to 100 parts of the acrylic polymer contained in the solution, and stirring to mix.

[0177] The above adhesive composition was applied to both main surfaces of a 12 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 50 μm thick double-sided tape with a substrate having a 19 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as adhesive sheet C1.

[0178] (Adhesive Sheet C2) The adhesive composition used was the same as that prepared in the production of Adhesive Sheet C1. The adhesive composition was applied to both main surfaces of a 25 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 100 μm thick double-sided tape with a substrate having a 37.5 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as Adhesive Sheet C2.

[0179] (Adhesive Sheet C3) The adhesive composition used was the same as that prepared in the production of Adhesive Sheet C1. The adhesive composition was applied to both main surfaces of a 75 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 150 μm thick double-sided tape with a substrate, having a 37.5 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as Adhesive Sheet C3.

[0180] (Adhesive Sheet D1) As an adhesive composition, an adhesive composition according to Example 6 described in paragraph

[0150] of Japanese Patent Publication No. 2022-47704 was prepared. Specifically, 95 parts of n-butyl acrylate (BA) and 5 parts of acrylic acid (AA) as monomer components, and 233 parts of ethyl acetate as a polymerization solvent were charged into a reaction vessel equipped with a stirrer, thermometer, nitrogen gas introduction tube, reflux condenser, and dropping funnel, and the mixture was stirred for 2 hours while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and solution polymerization was carried out at 60°C for 8 hours to obtain a solution of acrylic polymer (A1). The Mw of this acrylic polymer (A1) is approximately 70 × 10 4The above acrylic polymer solution was prepared by adding 25 parts of acrylic oligomer, 1 part of an isocyanate-based crosslinking agent, and 0.075 parts of an epoxy-based crosslinking agent to 100 parts of the acrylic polymer (A1) contained in the solution, and stirring and mixing to prepare an adhesive composition. The acrylic oligomer used was prepared by the following method. Specifically, 95 parts of cyclohexyl methacrylate (CHMA), 5 parts of acrylic acid (AA), 10 parts of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and toluene as a polymerization solvent were charged into a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, reflux condenser, and dropping funnel. The mixture was stirred in a nitrogen stream for 1 hour to remove oxygen from the polymerization system, then the temperature was raised to 85°C and the mixture was reacted for 5 hours to obtain an acrylic oligomer with a solid content of 50%. The Mw of the obtained acrylic oligomer was 3600. As the isocyanate-based crosslinking agent, Coronate L (manufactured by Tosoh Corporation, a 75% ethyl acetate solution of trimethylolpropane / tolylene diisocyanate trimer adduct) was used. As the epoxy-based crosslinking agent, TETRAD-C (manufactured by Mitsubishi Gas Chemical Company, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was used.

[0181] The above adhesive composition was applied to both main surfaces of a 12 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 50 μm thick double-sided tape with a substrate having a 19 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as adhesive sheet D1.

[0182] (Adhesive Sheet D2) The adhesive composition used was the same as that prepared in the production of Adhesive Sheet D1. The adhesive composition was applied to both main surfaces of a 25 μm thick PET film (manufactured by Toray Industries, Ltd., Lumirror) and dried. This resulted in a 100 μm thick double-sided tape with a substrate, having a 37.5 μm thick adhesive layer on both sides. The obtained double-sided tape with a substrate was designated as Adhesive Sheet D2.

[0183] [Configuration of Waterproofing Member] (Examples 1-15 and Comparative Examples 3-6) The configuration of the waterproofing member 100 used in Examples 1-15 and Comparative Examples 3-6 will be described below. Figure 7 is a cross-sectional view showing the configuration of the waterproofing member 100 in Examples 1-15 and Comparative Examples 3-6. As shown in Figure 7, the waterproofing member 100 comprises a first waterproofing membrane 111, a second waterproofing membrane 112, an annular inner adhesive layer 121 joined to the second main surface 111b of the first waterproofing membrane 111 and the first main surface 112a of the second waterproofing membrane 112, an annular first outer adhesive layer 131 joined to the first main surface 111a of the first waterproofing membrane 111, and an annular second outer adhesive layer 132 joined to the second main surface 112b of the second waterproofing membrane 112. The first waterproofing membrane 111 and the second waterproofing membrane 112 were spaced apart. The outer diameter R100 of the waterproofing member 100 was 5.8 mm, and the inner diameter r100 corresponding to the sound transmission region 140 was 1.6 mm.

[0184] (Comparative Examples 1-2) The configuration of the waterproof member 200 used in Comparative Examples 1-2 will be described. Figure 8 is a cross-sectional view showing the configuration of the waterproof member 200 of Comparative Examples 1-2. As shown in Figure 8, the waterproof member 200 comprises a first waterproof membrane 211, an annular first outer adhesive layer 231 joined to the first main surface 211a of the first waterproof membrane 211, and an annular second outer adhesive layer 232 joined to the second main surface 211b of the first waterproof membrane 211. The waterproof member 200 had a single-layer structure without a second waterproof membrane. The outer diameter R200 of the waterproof member 200 was 5.8 mm, and the inner diameter r200 corresponding to the sound-permeable region 240 was 1.6 mm.

[0185] [Example 1] A waterproof member 100 having the configuration shown in Figure 7 was manufactured. Waterproof membrane α was used as the first waterproof membrane 111. Waterproof membrane β was used as the second waterproof membrane 112. Adhesive sheet A1 was used as the inner adhesive sheet for forming the inner adhesive layer 121. Adhesive sheet D2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131 and the second outer adhesive sheet for forming the second outer adhesive layer 132. Circular holes with an inner diameter r100 of 1.6 mm corresponding to the sound-permeable region 140 were pre-formed in each adhesive sheet. The first outer adhesive sheet, the first waterproof membrane 111, the inner adhesive sheet, the second waterproof membrane 112, and the second outer adhesive sheet were bonded together in this order to achieve the configuration shown in Figure 7, and then punched out into a circular shape with an outer diameter R100 of 5.8 mm. In this way, the waterproof member 100 of Example 1 was obtained.

[0186] [Example 2] Waterproof membrane α was used as the second waterproof membrane 112. The waterproof member 100 of Example 2 was manufactured in the same manner as in Example 1, except for this difference.

[0187] [Example 3] For forming the inner adhesive layer 121, an adhesive sheet C1 was used. The waterproof member 100 of Example 3 was manufactured in the same manner as in Example 1.

[0188] [Example 4] Adhesive sheet B was used as the inner adhesive sheet for forming the inner adhesive layer 121. The waterproof member 100 of Example 4 was manufactured in the same manner as in Example 1.

[0189] [Example 5] Adhesive sheet C2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131 and the second outer adhesive sheet for forming the second outer adhesive layer 132. The waterproof member 100 of Example 5 was manufactured in the same manner as in Example 1.

[0190] [Example 6] Adhesive sheet C1 was used as the inner adhesive sheet for forming the inner adhesive layer 121. Adhesive sheet A2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131 and the second outer adhesive sheet for forming the second outer adhesive layer 132. The waterproof member 100 of Example 6 was manufactured in the same manner as in Example 1, except for these differences.

[0191] [Example 7] Adhesive sheet B was used as the inner adhesive sheet for forming the inner adhesive layer 121. The waterproof member 100 of Example 7 was manufactured in the same manner as in Example 6.

[0192] [Example 8] Waterproof membrane α was used as the second waterproof membrane 112. The waterproof member 100 of Example 8 was manufactured in the same manner as in Example 7, except for this difference.

[0193] [Example 9] For forming the first outer adhesive layer 131, adhesive sheet C3 was used. For forming the second outer adhesive layer 132, adhesive sheet D1 was used. Except for these, the waterproof member 100 of Example 9 was manufactured in the same manner as in Example 1.

[0194] [Example 10] Waterproof membrane α was used as the second waterproof membrane 112. The waterproof member 100 of Example 10 was manufactured in the same manner as in Example 9, except for this difference.

[0195] [Example 11] Adhesive sheet C3 was used as the inner adhesive sheet for forming the inner adhesive layer 121. Adhesive sheet A2 was used as the second outer adhesive sheet for forming the second outer adhesive layer 132. The waterproof member 100 of Example 11 was manufactured in the same manner as in Example 9, except for these differences.

[0196] [Example 12] Waterproof membrane α was used as the second waterproof membrane 112. The waterproof member 100 of Example 12 was manufactured in the same manner as in Example 11, except for this difference.

[0197] [Example 13] Adhesive sheet A2 was used as the inner adhesive sheet for forming the inner adhesive layer 121. The waterproof member 100 of Example 13 was manufactured in the same manner as in Example 1.

[0198] [Example 14] Waterproof membrane γ was used as the first waterproof membrane 111 and the second waterproof membrane 112. Adhesive sheet C2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131 and the second outer adhesive sheet for forming the second outer adhesive layer 132. The waterproof member 100 of Example 14 was manufactured in the same manner as in Example 1, except for these differences.

[0199] [Example 15] Waterproof membrane δ was used as the first waterproof membrane 111 and the second waterproof membrane 112. The waterproof member 100 of Example 15 was manufactured in the same manner as in Example 14.

[0200] [Comparative Example 1] A waterproof member 200 having the configuration shown in Figure 8 was fabricated. Waterproof membrane β was used as the first waterproof membrane 211. Adhesive sheet C2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131. Adhesive sheet D2 was used as the second outer adhesive sheet for forming the second outer adhesive layer 132. Circular holes with an inner diameter r200 of 1.6 mm corresponding to the sound-permeable region 240 were pre-formed in each adhesive sheet. The first outer adhesive sheet, the first waterproof membrane 211, and the second outer adhesive sheet were bonded together in this order to achieve the configuration shown in Figure 8, and then punched out into a circular shape with an outer diameter R200 of 5.8 mm. In this way, the waterproof member 200 of Comparative Example 1 was obtained.

[0201] [Comparative Example 2] Waterproof membrane α was used as the first waterproof membrane 211. The waterproof member 200 of Comparative Example 2 was manufactured in the same manner as in Comparative Example 1.

[0202] [Comparative Example 3] A waterproof member 100 having the configuration shown in Figure 7 was manufactured. Adhesive sheet D1 was used as the inner adhesive sheet for forming the inner adhesive layer 121. Adhesive sheet A2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131 and the second outer adhesive sheet for forming the second outer adhesive layer 132. The waterproof member 100 of Comparative Example 3 was manufactured in the same manner as in Example 1, except for these differences.

[0203] [Comparative Example 4] Waterproof membrane α was used as the second waterproof membrane 112. The waterproof member 100 of Comparative Example 4 was manufactured in the same manner as in Comparative Example 3.

[0204] [Comparative Example 5] Adhesive sheet D1 was used as the inner adhesive sheet for forming the inner adhesive layer 121. Adhesive sheet C2 was used as the first outer adhesive sheet for forming the first outer adhesive layer 131. The waterproof member 100 of Comparative Example 5 was manufactured in the same manner as in Example 1, except for these differences.

[0205] [Comparative Example 6] Waterproof membrane α was used as the second waterproof membrane 112. The waterproof member 100 of Comparative Example 6 was manufactured in the same manner as in Comparative Example 5, except for this difference.

[0206] (Evaluation of Storage Modulus G') For the waterproof members of Examples 1 to 15 and Comparative Examples 1 to 6, the storage modulus G' at 25°C of the inner adhesive layer, the storage modulus G' at 25°C of the first outer adhesive layer, and the storage modulus G' at 25°C of the second outer adhesive layer were measured using the method described above. The results are shown in Table 1.

[0207] (Evaluation of Thickness) For the waterproofing members of Examples 1 to 15 and Comparative Examples 1 to 6, the thickness of the first waterproofing membrane, the thickness of the second waterproofing membrane, the thickness of the inner adhesive layer, the thickness of the first outer adhesive layer, and the thickness of the second outer adhesive layer were determined using the method described above. The results are shown in Table 1.

[0208]

[0209] (Evaluation of Insertion Loss) The method for measuring the insertion loss of waterproofing material for sounds in the frequency range of 1000 to 10000 Hz will be explained using Figure 9. The insertion loss was measured using a simulated housing modeled after the casing of a mobile phone, as shown in Figure 9, by the following method.

[0210] As shown in Figures 9(A) and (B), a speaker unit 155 to be housed inside a simulated enclosure was fabricated. Specifically, it was as follows: A speaker 160 (SCC-16A, manufactured by Star Micronics), which is the sound source, and fillers 150a, 150b, and 150c made of urethane sponge were prepared to house the speaker 160 and to prevent unnecessary diffusion of sound from the speaker (to minimize the generation of sound that is input to the evaluation microphone without passing through the waterproof material sample being evaluated). Filler 150a has a sound-conducting opening 152 with a circular cross-section of 5.0 mm in diameter provided in the thickness direction. Filler 150b has a notch with a shape corresponding to the shape of the speaker 160 and a notch for housing the speaker cable 162 and for leading the speaker cable 162 out of the speaker unit 155. Next, the filler materials 150c and 150b were stacked, and the speaker 160 and speaker cable 162 were housed in the notch of the filler material 150b (Figure 9(A)). Then, the filler material 150a was stacked on top so that sound could be transmitted from the speaker 160 to the outside of the speaker unit 155 through the sound transmission opening 152, thereby obtaining the speaker unit 155 (Figure 9(B)).

[0211] Next, as shown in Figure 9(C), the speaker unit 155 prepared above was housed inside a simulated housing 170 (made of polystyrene, with external dimensions of 60 mm x 50 mm x 28 mm) that mimicked the casing of a mobile phone. Specifically, it was as follows: The prepared simulated housing 170 consisted of two parts 170a and 170b, which could be fitted together. Part 170a was provided with a sound vent 172 (having a circular cross-section with a diameter of 1.0 mm) that transmitted sound emitted from the speaker unit 155 housed inside to the outside of the simulated housing 170, and a passage hole 174 that led the speaker cable 162 to the outside of the simulated housing 170. By fitting parts 170a and 170b together, a space was formed inside the simulated housing 170 with no openings other than the sound vent 172 and the passage hole 174. After placing the fabricated speaker unit 155 on section 170b, sections 170a and 170b were fitted together to house the speaker unit 155 inside the simulated housing 170. At this time, the sound vent 152 of the speaker unit 155 and the sound vent 172 of section 170a were overlapped so that sound could be transmitted from the speaker 160 to the outside of the simulated housing 170 through both sound vents 152 and 172. The speaker cable 162 was routed to the outside of the simulated housing 170 through the conduction hole 174, and the conduction hole 174 was sealed with putty.

[0212] Next, as shown in Figure 9(D), a sample S (outer diameter 5.8 mm) of the waterproofing member to be evaluated was fixed to the sound-conducting opening 172 of the simulated housing 170 using the first outer adhesive layer. The sample S was fixed so that, when viewed from a direction perpendicular to the main surface of the first waterproofing membrane, the entire sound-conducting area of ​​the sample S was located within the opening of the sound-conducting opening 172.

[0213] Next, as shown in Figure 9(E), a microphone 180 (SPU0410LR5H, manufactured by Knowles Acoustics) was fixed to the sample S so as to cover the sound transmission area of ​​the sample S. The microphone 180 was fixed by the second outer adhesive layer of the sample S. The distance between the speaker 160 and the microphone 180 when the microphone 180 was fixed varied by up to about 2 mm depending on the thickness of the waterproof material being evaluated, but was in the range of approximately 22 to 24 mm. Next, speaker 160 and microphone 180 were connected to an acoustic evaluation device (B&K Multi-analyzer System 3560-B-030), and the SSR (Solid State Response) mode (test signal 20 Hz to 20 kHz, sweep up) was selected as the evaluation method and executed to evaluate the insertion loss of sample S for sounds in the frequency range of 1000 to 10000 Hz. The insertion loss is automatically determined from the test signal input to speaker 160 from the acoustic evaluation device and the signal received by microphone 180. In evaluating the insertion loss of sample S, the value of the insertion loss when sample S is removed (blank value) was determined in advance. The blank value was -37 dB at a frequency of 1 kHz. The insertion loss of sample S is the value obtained by subtracting this blank value from the measurement value obtained by the acoustic evaluation device. The smaller the insertion loss value, the better the level (volume) of the sound output from speaker 160 is maintained.

[0214] For the waterproofing members of Examples 1 to 15 and Comparative Examples 1 to 6, the insertion loss for sound in the frequency range of 1000 to 10000 Hz of sample S was measured using the method described above, and the measured value was considered to be the insertion loss of the waterproofing member for sound in the frequency range of 1000 to 10000 Hz. Figure 10 shows the relationship between the insertion loss and frequency of the waterproofing members of Examples 1 to 13. Figure 11 shows the relationship between the insertion loss and frequency of the waterproofing members of Examples 14 to 15. Figure 12 shows the relationship between the insertion loss and frequency of the waterproofing members of Comparative Examples 1 to 6. In Figures 10 to 12, the vertical axis represents insertion loss (dB), and the horizontal axis represents frequency (Hz). If the insertion loss for sound in the entire frequency range of 300 to 10000 Hz was 7.5 dB or less, it was evaluated as "YES," and all others as "NO." The results are shown in Table 2.

[0215] (Evaluation of Water Resistance) For the waterproofing members of Examples 1 to 15 and Comparative Examples 1 to 6, a water pressure holding test was conducted using the method described above. When a circular water pressure application surface with a diameter of 1.6 mm was set up, it was evaluated whether the waterproofing members had the water resistance to withstand a water pressure holding test in which they were exposed to pure water at a water pressure of 1.0 MPa for 30 minutes. Those that possessed the above water resistance were evaluated as "YES," and all others were evaluated as "NO." The results are shown in Table 2.

[0216] For the waterproofing members of Examples 1 to 15 and Comparative Examples 1 to 6, we evaluated whether they possessed sufficient water retention resistance to withstand a water pressure retention test in which they were exposed to soapy water (soap concentration 0.5 wt%) at a water pressure of 0.5 MPa for 10 minutes, when a circular water pressure application surface with a diameter of 1.6 mm was set up using the method described above. Those that possessed the above water retention resistance were evaluated as "YES," and all others as "NO." The results are shown in Table 2.

[0217] (Evaluation of Appearance) The appearance of the first and second waterproof membranes of the waterproofing members of Examples 1 to 15 and Comparative Examples 1 to 6 was evaluated visually. Those in which there were no wrinkles or creases at all were evaluated as "YES," and those in which wrinkles or creases were clearly present were evaluated as "NO." Those in which wrinkles or creases were slightly present were evaluated as "NEUTRAL." The results are shown in Table 2.

[0218]

[0219] As can be seen from the comparison of the results of Examples 1 to 15 and Comparative Examples 3 to 6 in Table 2 with the results of Comparative Examples 1 to 2, the waterproof members with a two-layer waterproof membrane structure had superior water retention resistance compared to the waterproof members with a single-layer waterproof membrane structure. Furthermore, for the waterproof members with a two-layer waterproof membrane structure, as can be seen from the comparison of the results of Examples 1 to 15 and Comparative Examples 3 to 6 in Table 2 and Figures 10 to 12, the waterproof members satisfying the requirement that the storage modulus G' of the inner adhesive layer at 25°C be 0.27 MPa or less had an insertion loss of 7.5 dB or less for sounds in the frequency range of 1000 to 10000 Hz, showing superior sound transmission characteristics compared to waterproof members that did not satisfy the above requirement. From these results, it can be concluded that the waterproof members of Examples 1 to 15 are suitable for achieving both waterproofness and sound transmission characteristics.

[0220] Furthermore, as can be seen from the comparison of the results of Examples 1-5 and 9-15 in Table 2 with the results of Examples 6-8, waterproof members in which the storage modulus G' of the first outer adhesive layer at 25°C is equal to or greater than the storage modulus G' of the inner adhesive layer at 25°C showed no wrinkles or creases at all in the first and second waterproof membranes (YES) and had an excellent appearance. From these results, it is considered that the deterioration of sound transmission characteristics over time is also suppressed in the waterproof members of Examples 1-5 and 9-15.

[0221] The waterproofing member of Example 1 and the waterproofing member of Example 13 had the same configuration except for the difference in the thickness of the inner adhesive layer. As can be seen from the comparison of the results of Example 1 and Example 13 in Table 2 and Figure 10, the waterproofing member of Example 1, in which the thickness of the first outer adhesive layer and the thickness of the second outer adhesive layer were greater than the thickness of the inner adhesive layer, showed superior sound transmission characteristics compared to the waterproofing member of Example 13, which did not satisfy this condition. From these results, it can be concluded that when the thickness of the first outer adhesive layer and the thickness of the second outer adhesive layer are greater than the thickness of the inner adhesive layer, there is a tendency for sound transmission characteristics to improve.

[0222] In the above embodiment, PTFE stretched porous membrane, PE porous membrane, and PET film were used as the first and second waterproof membranes. However, it is presumed that similar effects can be expected even if other materials, such as a silicone non-porous membrane, are used. This is because the present invention achieves the above effects by controlling the storage modulus G' at 25°C within a specific range for the inner adhesive layer bonded between the first and second waterproof membranes.

[0223] The technology of the present invention can be applied to various electronic devices such as wearable devices like smartwatches; various cameras; communication devices such as mobile phones and smartphones; and sensor devices.

Claims

1. A waterproof member disposed to close an opening in an object having an opening surface, comprising: a first waterproof membrane having a first main surface facing the opening and a second main surface opposite to the first main surface when disposed to close the opening; a second waterproof membrane disposed spaced apart from the first waterproof membrane and having a first main surface facing the second main surface of the first waterproof membrane and a second main surface opposite to the first main surface; and an inner adhesive layer bonded to the second main surface of the first waterproof membrane and the first main surface of the second waterproof membrane, wherein the storage modulus G' of the inner adhesive layer at 25°C is 0.27 MPa or less.

2. The waterproof member according to claim 1, further comprising a first outer adhesive layer bonded to the first main surface of the first waterproof membrane, wherein the storage modulus G' of the first outer adhesive layer at 25°C is equal to or greater than the storage modulus G' of the inner adhesive layer at 25°C.

3. The waterproof member according to claim 2, further comprising a second outer adhesive layer bonded to the second main surface of the second waterproof membrane, wherein the storage modulus G' of the second outer adhesive layer at 25°C is greater than the storage modulus G' of the inner adhesive layer at 25°C.

4. The waterproof member according to claim 3, wherein the storage modulus G' of the first outer adhesive layer at 25°C and the storage modulus G' of the second outer adhesive layer at 25°C are 0.20 MPa or more.

5. The waterproof member according to claim 3, wherein at least one selected from the group consisting of the thickness of the first outer adhesive layer and the thickness of the second outer adhesive layer is equal to or greater than the thickness of the inner adhesive layer.

6. The waterproof member according to claim 5, wherein the thickness of the inner adhesive layer is 30 μm or more and 150 μm or less.

7. The waterproof member according to claim 1, wherein the insertion loss in the frequency range of 1000 to 10000 Hz is 7.5 dB or less.

8. The waterproof member according to claim 1, which has water-holding resistance capable of withstanding a water pressure holding test in which a circular water pressure application surface with a diameter of 1.6 mm is set and the member is exposed to pure water at a water pressure of 1.0 MPa for 30 minutes.

9. The waterproof member according to claim 1, which has water-holding resistance capable of withstanding a water pressure holding test in which a circular water pressure application surface with a diameter of 1.6 mm is set and the member is exposed to soapy water (soap concentration 0.5 wt%) at a water pressure of 0.5 MPa for 10 minutes.

10. The waterproof member according to claim 1, wherein the first waterproof membrane and the second waterproof membrane each contain at least one selected from the group consisting of polytetrafluoroethylene, polyolefin, polyimide, silicone, polyurethane, and polyethylene terephthalate.

11. The waterproofing member according to claim 1, wherein the first waterproofing membrane and the second waterproofing membrane are porous membranes or non-porous membranes.

12. An electronic device comprising a housing having an opening formed therein, and a waterproof member according to any one of claims 1 to 11, disposed on the housing so as to close the opening.

13. A component supply assembly comprising: a waterproof member disposed to close the opening of an object having an opening surface in which an opening is formed; and a base sheet on which the waterproof member is disposed, wherein the waterproof member is the waterproof member described in any one of claims 1 to 11.

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