Venting configurations and porous membranes

Abstract

The venting structure (100) includes a housing (20) having an opening (21) and a porous membrane (10) ultrasonically welded to the housing (20) to seal the opening (21). The porous membrane (10) has a first main surface (10a) facing the opening (21) and a second main surface (10b) facing the side opposite to the opening (21). When the maximum stress when the pressing pin is pressed from the first main surface (10a) side of the porous membrane (10) is defined as the weld strength of the porous membrane (10), the weld strength of the porous membrane (10) is in the range of 1.5N or more and 30N or less. The housing (20) includes, for example, the housing of an automotive component.

Description

Technical Field

[0001] This invention relates to ventilation structures and porous membranes. Background Technology

[0002] Previously, ventilated membranes were used in automotive components, electronic devices, and other applications to eliminate the pressure difference between the inside and outside of a housing. These ventilated membranes are installed on the housing by sealing the openings, ensuring ventilation while providing dust and water protection. Such ventilated membranes often utilize porous membranes with good air permeability.

[0003] The porous membrane, as a breathable membrane, is bonded to the housing of vehicle components, electronic devices, etc., by means of bonding with double-sided tape, adhesives, etc., or by welding with ultrasonic welding, thermal welding, laser welding, etc. While bonding is a simple method, it cannot be said to provide sufficient chemical resistance. In the case of housings for vehicle components, when engine oil, gasoline, etc., adhere to the double-sided tape, adhesives, etc., it may cause a decrease in bond strength. Therefore, it is preferable to bond the porous membrane to the housing of the vehicle component by welding, which is less affected by engine oil, gasoline, etc. For example, Patent Document 1 describes a technique for welding a breathable fluoropolymer porous membrane made of fluoropolymer onto the housing (resin component) for housing electrical components of an automobile.

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-205420 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] According to the technology described in Patent Document 1, while an improvement in the weld strength of the porous membrane relative to the shell can be expected, the protrusion on the working surface of the weld joint provided in the welding device is indispensable. A technology is desired that can utilize the inherent properties of the porous membrane to achieve excellent weld strength without relying on the structure of the welding device.

[0008] Therefore, the object of the present invention is to provide a ventilated structure that improves the weld strength of the porous membrane relative to the shell and a porous membrane that improves the weld strength relative to the shell.

[0009] Solution for solving the problem

[0010] This invention provides a ventilation structure comprising: The shell has an opening; and A porous membrane is ultrasonically welded to the housing in a manner that seals the openings. The aforementioned porous membrane has a first main surface facing the opening and a second main surface facing the side opposite to the opening. When the maximum stress when the pressing pin is pressed against the first main surface of the porous membrane is defined as the weld strength of the porous membrane, the weld strength of the porous membrane is in the range of 1.5N or more and 30N or less.

[0011] On the other hand, the present invention provides a porous membrane whose weld strength, as determined by the following weld strength measurement test, is in the range of 1.5N or more and 30N or less.

[0012] <Test for Determination of Weld Strength>

[0013] A sample body is fabricated by ultrasonically welding the porous membrane to a housing having an opening, thereby sealing the opening. In the sample body, the porous membrane has a first main surface facing the opening and a second main surface facing the side opposite to the opening. For the sample body, the maximum stress when a pressing pin is applied from the first main surface side of the porous membrane is measured. This measured value is set as the weld strength of the porous membrane.

[0014] Invention Effects

[0015] According to the present invention, it is possible to provide a ventilated structure that improves the weld strength of the porous membrane relative to the shell and a porous membrane that improves the weld strength relative to the shell. Attached Figure Description

[0016] Figure 1A This is a cross-sectional view schematically illustrating an example of the porous membrane of the present invention.

[0017] Figure 1B It is a schematic representation Figure 1A A top view of a porous membrane.

[0018] Figure 2A This is a cross-sectional view schematically illustrating an example of the ventilation structure of the present invention.

[0019] Figure 2B It is a schematic representation Figure 2A A top view of the ventilation structure.

[0020] Figure 3 This is a cross-sectional view schematically illustrating an example of a welding device.

[0021] Figure 4 This is a schematic diagram used to illustrate the test for determining weld strength.

[0022] Figure 5 This is a scanning electron microscope (SEM) image of the cross-section of the PTFE porous membrane of Example 3. Detailed Implementation

[0023] The ventilation structure of the first aspect of the present invention comprises: The shell has an opening; and A porous membrane is ultrasonically welded to the housing in a manner that seals the openings. The aforementioned porous membrane has a first main surface facing the opening and a second main surface facing the side opposite to the opening. When the maximum stress when the pressing pin is pressed against the first main surface of the porous membrane is defined as the weld strength of the porous membrane, the weld strength of the porous membrane is in the range of 1.5N or more and 30N or less.

[0024] In a second aspect of the present invention, for example, based on the ventilated structure of the first aspect, the porous membrane comprises fibrils and nodes connected to the fibrils, and the average node area of ​​the porous membrane is greater than 100 μm. 2 And 500μm 2 The following range.

[0025] In a third aspect of the present invention, for example, the ventilation structure of the first or second aspect has: a first region in which the shell and the porous membrane are present, including a welded portion formed between the shell and the porous membrane; and a second region in which the shell is absent and the porous membrane is exposed, wherein the average thickness of the porous membrane in the second region is in the range of 120 μm or more and 350 μm or less.

[0026] In the fourth aspect of the present invention, for example, based on the ventilation structure of any of the first to third aspects, the gravimetric permeability of the porous membrane is in the range of 3 seconds / 100 mL or more and 40 seconds / 100 mL or less.

[0027] In the fifth aspect of the invention, for example, based on the ventilation structure of any of the first to fourth aspects, the aforementioned shell is formed of thermoplastic resin.

[0028] In the sixth aspect of the present invention, for example, based on the ventilation structure of any of the first to fifth aspects, the aforementioned housing includes the housing of the vehicle-mounted component.

[0029] The porous membrane of the seventh embodiment of the present invention has a weld strength that is between 1.5 N and 30 N, as determined by the weld strength determination test described below.

[0030] <Test for Determination of Weld Strength>

[0031] A sample body is fabricated by ultrasonically welding the porous membrane to a housing having an opening, thereby sealing the opening. In the sample body, the porous membrane has a first main surface facing the opening and a second main surface facing the side opposite to the opening. For the sample body, the maximum stress when a pressing pin is applied from the first main surface side of the porous membrane is measured. This measured value is set as the weld strength of the porous membrane.

[0032] In the eighth aspect of the present invention, for example, the porous membrane of the seventh aspect comprises fibrils and nodes connected to the fibrils, wherein the average node area of ​​the porous membrane is greater than 100 μm. 2 And 500μm 2 The following range.

[0033] In the ninth aspect of the present invention, for example, the average thickness of the porous membrane in the seventh or eighth aspect is in the range of 120 μm or more and 350 μm or less.

[0034] In the tenth aspect of the present invention, for example, based on the porous membrane of any of the seventh to ninth aspects, the gravimetric permeability of the porous membrane is in the range of 3 seconds / 100 mL or more and 40 seconds / 100 mL or less.

[0035] In the eleventh aspect of the present invention, for example, the porous membrane of any of the seventh to tenth aspects is used as a ventilation membrane for vehicle components.

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments.

[0037] [Porous membrane]

[0038] Figure 1A This is a cross-sectional view schematically illustrating an example of the porous membrane 10 of the present invention. Figure 1B It is a schematic representation Figure 1A A top view of the porous membrane 10. (See figure) Figure 1B As shown, the porous membrane 10 has a circular shape when viewed from above. The weld strength S of the porous membrane 10 in this embodiment is in the range of 1.5 N or more and 30 N or less.

[0039] In the technology described in Patent Document 1, a protrusion on the working surface of the weld joint in the welding device is indispensable in order to improve the welding strength of the porous membrane relative to the shell. In contrast, the porous membrane 10 of this embodiment has a welding strength S in the range of 1.5N or more and 30N or less due to the inherent characteristics of the porous membrane itself, and has excellent welding strength S.

[0040] <Test for Determination of Weld Strength>

[0041] The weld strength S of the porous membrane 10 can be determined by the test described below. Figure 3 This is a cross-sectional view schematically showing an example of the welding device 50. Figure 4 This is a schematic diagram illustrating the test for determining weld strength S. First, as... Figure 3 As shown, a porous membrane 10 with a diameter d10 of 10 mm is concentrically arranged on a housing 20 having a circular opening 21 with a diameter d20 of 4.9 mm, with the opening 21 sealed. Next, using a welding device 50 and a welding joint 51, the porous membrane 10 is ultrasonically welded to the housing 20 to create a sample body 101. The welding joint 51 has an annular shape when viewed from above. The inner diameter d1 of the welding joint 51 is 6.6 mm, and the outer diameter d2 is 8.2 mm. The frequency used to create the sample body 101 is 35 kHz, the amplitude is 32.5 μm, the contact load (load on the welding joint 51 before ultrasonic application) is 25 N, the welding load (load on the welding joint 51 during ultrasonic application) is 50 N, and the welding energy is 30 J. The stop mode is set to "energy". Next, as... Figure 4 As shown, a sample body 101 is mounted on a tensile testing machine. In the sample body 101, the porous membrane 10 has a first main surface 10a facing the opening 21 and a second main surface 10b facing the side opposite to the opening 21. For the sample body 101, the maximum stress σ is measured when a pressing pin 600 with a diameter of 4 mm and a front end diameter of 2 mm is pressed from the first main surface 10a side of the porous membrane 10 at a rate of 1 mm / min. The measured maximum stress σ is set as the weld strength S of the porous membrane 10. The weld strength S can also be the average of the maximum stress σ measured on multiple (e.g., 5) sample bodies 101. Furthermore, in this invention, "main surface" refers to the surface with the largest area of ​​a sheet-like or film-like component.

[0042] In this embodiment, the porous membrane 10 is used without layering nonwoven fabric, mesh or other supporting materials.

[0043] The lower limit of the weld strength S of the porous membrane 10 can be 2.5N or more, 5N or more, 7.5N or more, or even 10N or more. The upper limit of the weld strength S of the porous membrane 10 can be 29N or less, 28N or less, or even 27N or less.

[0044] The porous membrane 10 can be a single-layer membrane. The porous membrane 10 can also be a multi-layered membrane.

[0045] The porous membrane 10 can be a fluoropolymer porous membrane. A fluoropolymer porous membrane is a porous membrane formed by stretching or similar processes to porousen a fluoropolymer membrane, typically through biaxial stretching. The fluoropolymer porous membrane may contain numerous fibrils formed during stretching and nodes connecting these fibrils. Nodes and fibrils are formed by stretching the fluoropolymer sheet. The composition of the nodes and fibrils varies, for example, depending on the stretching conditions of the fluoropolymer sheet.

[0046] Examples of fluoropolymers included in fluoropolymer porous membranes include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and tetrafluoroethylene-ethylene copolymer.

[0047] Fluoropolymers can be PTFE. That is, fluoropolymer porous membranes can be PTFE porous membranes. PTFE porous membranes have excellent water resistance and dustproof properties, thus effectively preventing water and dirt from penetrating the interior of the casing.

[0048] When the porous membrane 10 includes fibrils and nodes, the length L1 of the nodes in the longitudinal direction is preferably in the range of 5 μm or more and 80 μm or less, and the length L2 of the nodes in the width direction is preferably in the range of 1 μm or more and 30 μm or less. When the length L1 in the longitudinal direction and the length L2 in the width direction of the nodes included in the porous membrane 10 are within the above-mentioned value range, it is easy to satisfy the requirement that the weld strength S is in the range of 1.5 N or more and 30 N or less.

[0049] The lower limit of the node's length L1 in the longitudinal direction can be 10 μm or more. The upper limit of the node's length L1 in the longitudinal direction can be 70 μm or less. The lower limit of the node's length L2 in the width direction can be 5 μm or more. The upper limit of the node's length L2 in the width direction can be 20 μm or less.

[0050] When the porous membrane 10 includes fibrils and nodes, the average node area An of the porous membrane 10 is preferably greater than 100 μm. 2 And 500μm 2 The following range applies. When the average node area An of the porous membrane 10 is within the above-mentioned range, it is easy to satisfy the requirement that the weld strength S is above 1.5N and below 30N.

[0051] The lower limit of the average node area An of the porous membrane 10 can be 110 μm. 2 The above can also be 120μm. 2 The above can be further improved to 130μm. 2 The upper limit of the average node area An of the porous membrane 10 can be 450 μm. 2 Below that, it can be 400μm 2 Below that, 350μm is acceptable.2 Further, it can be 300μm. 2 the following.

[0052] When the porous membrane 10 includes fibrils and nodes, the porous membrane 10 preferably has a structure in which the nodes are connected in the elongation direction of the fibrils. With a porous membrane 10 having such a structure, it is easy to satisfy the requirement that the weld strength S is in the range of 4.5 N or more.

[0053] The lower limit of the average node area An of the porous membrane 10 can be 200 μm. 2 The above can be further improved to 250μm. 2 The above applies. When the lower limit of the average node area An of the porous membrane 10 is within the above-mentioned numerical range, the porous membrane 10 is likely to have a structure in which the nodes are connected in the elongation direction of the protofibrils.

[0054] <Methods for determining node length and node area>

[0055] The length L1 in the longitudinal direction, the length L2 in the width direction, and the average node area An of the nodes contained in the porous membrane 10 can be determined by the measurement method described below. First, observe the cross-section obtained by cutting the porous membrane 10 parallel to the thickness direction using a scanning electron microscope (SEM). Next, binarize the obtained SEM observation image (or a portion thereof) using image software (e.g., ImageJ). Remove fibrils from the obtained binarized image, creating an image of only the nodes. In the fibril removal process, fibrils can be removed by magnifying the binarized image and blackening the fibril areas. For the n nodes contained in the obtained image containing only nodes, calculate the length in the longitudinal direction, the length in the width direction, and the area. For example, the length in the longitudinal direction, the length in the width direction, and the area of ​​the nodes can be calculated using an observation image containing at least 10 (n=10) nodes. Set the average of the calculated lengths in the longitudinal direction as the length L1 of the node in the longitudinal direction. Set the average of the calculated lengths in the width direction as the length L2 of the node in the width direction. Set the average of the calculated areas as the average node area An. Furthermore, in obtaining the length, width, and area of ​​the nodes, a sufficiently large observation image should be used that can be judged to represent the entire cross-section obtained by cutting the porous membrane 10 parallel to the thickness direction. The observation image preferably includes a region of at least 120 μm × 90 μm.

[0056] When the porous membrane 10 includes fibrils and nodes, the length L3 of the fibrils in the longitudinal direction is preferably in the range of 8 μm or more and 30 μm or less. When the length L3 of the fibrils included in the porous membrane 10 in the longitudinal direction is within the above-mentioned range, it is easy to satisfy the requirement that the weld strength S is in the range of 1.5 N or more and 30 N or less.

[0057] The length L3 of the fibrils contained in the porous membrane 10 in the longitudinal direction can be determined by the measurement method described below. In the above-described method for measuring node length and node area, nodes are removed from the obtained binarized image to create an image containing only fibrils. For each of the N fibrils contained in the obtained image containing only fibrils, the length in the longitudinal direction is calculated. For example, an observation image containing at least 100 (N=100) fibrils can be used to calculate the length in the longitudinal direction of the fibrils. The average value of the calculated lengths in the longitudinal direction is set as the length L3 of the fibrils in the longitudinal direction.

[0058] The average thickness of the porous membrane 10 is preferably in the range of 120 μm or more and 350 μm or less. When the average thickness of the porous membrane 10 is within the above-mentioned range, it is easy to satisfy the requirement that the weld strength S is in the range of 1.5 N or more and 30 N or less.

[0059] The lower limit of the average thickness of the porous membrane 10 can be 125 μm or more, 135 μm or more, 150 μm or more, or even 175 μm or more. The upper limit of the average thickness of the porous membrane 10 can be 340 μm or less, 330 μm or less, or even 320 μm or less.

[0060] <Methods for measuring thickness>

[0061] The average thickness of the porous membrane 10 can be determined, for example, by measuring the thickness at any five points on the porous membrane 10 using a dial indicator and averaging these measurements. Alternatively, the average thickness of the porous membrane 10 can be determined by measuring the thickness at any five points in a SEM image of the cross-section of the porous membrane 10 and averaging these measurements.

[0062] More preferably, the average node area An of the porous membrane 10 is greater than 100 μm. 2 And 500μm 2 The average thickness is between 120 μm and 350 μm. When the average node area An of the porous membrane 10 is within the above-mentioned range and the average thickness of the porous membrane 10 is within the above-mentioned range, it is easier to satisfy the weld strength S being between 1.5 N and 30 N.

[0063] The preferred Glycol permeability of the porous membrane 10 is in the range of 3 seconds / 100 mL or more and 40 seconds / 100 mL or less.

[0064] The lower limit of the gravimetric permeability of the porous membrane 10 can be greater than 5 seconds / 100 mL, greater than 7.5 seconds / 100 mL, or even greater than 10 seconds / 100 mL.

[0065] <Method for determining Glycol air permeability>

[0066] The Glyphic permeability of the porous membrane 10 can be determined according to the Glyphic tester method specified in JISP 8117:2009.

[0067] As described above, it is preferable to join the porous membrane 10 to the housing 20 by welding on the housing of the vehicle component. The weld strength S of the porous membrane 10 is in the range of 1.5N or more and 30N or less, exhibiting excellent weld strength S, and is therefore particularly suitable for use as a venting membrane for vehicle components.

[0068] The porous membrane 10 can be supplied, for example, in the form of strip-shaped components of the porous membrane 10 being attached in rows along the length of the strip-shaped substrate sheet. The porous membrane 10 can also be supplied, for example, in the form of sheet-shaped components of the porous membrane 10 being attached at equal intervals to the entire surface of the monolithic substrate sheet.

[0069] [Methods for manufacturing porous membranes]

[0070] The manufacturing method of the porous membrane 10 will be described below. The porous membrane 10 can be manufactured, for example, by the method described below. The method described below is an example when the porous membrane 10 is a PTFE porous membrane.

[0071] First, a liquid lubricant is uniformly mixed with PTFE micropowder. The mixture is then compressed into a barrel and extruded using a plunger extruder. This yields a sheet-shaped body extending in a predetermined direction. The sheet-shaped body, still containing the liquid lubricant, is calendered between calendering rolls. After removing the liquid lubricant by heating the sheet-shaped body, it is dried. Next, the sheet-shaped body is stretched only once along its length. This yields a PTFE porous membrane. By adjusting the stretching conditions, the properties of the PTFE porous membrane, such as the average nodal area An and the average thickness, can be controlled.

[0072] [Ventilation Structure]

[0073] Next, the ventilation structure of the present invention will be described. Figure 2A This is a cross-sectional view schematically illustrating an example of the ventilation structure 100 of the present invention. Figure 2B It is a schematic representation Figure 2AA top view of the ventilation structure 100. The ventilation structure 100 includes a housing 20 and a porous membrane 10 having the above-described features. Figure 2B As shown, the opening 21 of the housing 20 has a circular shape when viewed from above. Hereinafter, the description of the porous membrane 10 described above will sometimes be omitted.

[0074] The ventilated structure 100 includes a shell 20 with an opening 21 and a porous membrane 10 ultrasonically welded to the shell 20 to seal the opening 21. The porous membrane 10 has a first main surface 10a facing the opening 21 and a second main surface 10b facing the side opposite to the opening 21. The maximum stress σ when the pressing pin 60 is pressed from the first main surface 10a side of the porous membrane 10 is defined as the weld strength S of the porous membrane 10. At this time, the weld strength S of the porous membrane 10 is in the range of 1.5N or more and 30N or less. The weld strength S of the porous membrane 10 can be determined by the weld strength measurement test described above.

[0075] In the ventilation structure 100, the weld strength S of the porous membrane 10 is in the range of 1.5N or more and 30N or less, which is higher than that of ventilation structures using conventional porous membranes.

[0076] The lower limit of the weld strength S of the porous membrane 10 in the ventilation structure 100 can be 2.5N or more, or 5N or more, or 7.5N or more, or even 10N or more. The upper limit of the weld strength S of the porous membrane 10 can be 29N or less, or 28N or less, or even 27N or less.

[0077] like Figure 2A and Figure 4 As shown, a welded portion 30 is formed between the shell 20 and the porous membrane 10. This welded portion 30 is formed by melting and solidifying the material forming the shell 20 using ultrasonic welding. The welded portion 30 has a ring shape when viewed from above. For ease of understanding, in Figure 2B In the middle, it is indicated through the fusion joint 30.

[0078] like Figure 2A As shown, the ventilated structure 100 has a first region 11 containing the housing 20 and the porous membrane 10 and including the welded portion 30, and a second region 12 where the housing 20 is absent and the porous membrane 10 is exposed. Figure 2B As shown, the first region 11 has an annular shape when viewed from above. The second region 12 has a circular shape when viewed from above. As long as the first region 11 includes the welded portion 30, the outer edge 11a of the first region 11 may or may not overlap with the outer edge 30a of the welded portion 30. The inner edge 11b of the first region 11 may or may not overlap with the inner edge 30b of the welded portion 30.

[0079] The width 30d (radial length) of the welded portion 30 can be appropriately set, for example, based on the width 11d (radial length) of the first region 11. Alternatively, it can be based on... Figure 3 The width (radial length: (d2-d1) / 2) of the working surface 51 of the welding joint 51 in the welding device 50 shown is appropriately set. The width 30d of the welding portion 30 can, for example, be in the range of 0.5 mm or more and 1.5 mm or less.

[0080] In the ventilation structure 100, the average thickness of the porous membrane 10 in the second region 12 is preferably in the range of 120 μm or more and 350 μm or less. In addition, the average thickness of the flat region 12 of the porous membrane 10 in the second region 12 is the same as the average thickness of the porous membrane 10 before ultrasonic welding to the housing 20.

[0081] The lower limit of the average thickness of the porous membrane 10 in the second region 12 can be 125 μm or more, or 135 μm or more, or 150 μm or more, or even 175 μm or more. The upper limit of the average thickness of the porous membrane 10 in the second region 12 can be 340 μm or less, or 330 μm or less, or even 320 μm or less.

[0082] <Method for measuring the thickness of the second region>

[0083] The average thickness of the porous membrane 10 in the second region 12 can be determined, for example, by measuring the thickness at any five points of the porous membrane 10 in the second region 12 using a dial indicator, and then calculating the average of these measurements. Alternatively, the average thickness of the porous membrane 10 in the second region 12 can be determined by measuring the thickness at any five points in a cross-sectional SEM image of the porous membrane 10 in the second region 12, and then calculating the average of these measurements.

[0084] The weld strength S of the porous membrane 10 can vary depending on the material forming the housing 20. The material forming the housing 20 is preferably a resin, and particularly preferably a thermoplastic resin. The housing 20 may also be formed from a thermoplastic resin. When the housing 20 is formed from a thermoplastic resin, during ultrasonic welding, a weld portion 30 is easily formed between the housing 20 and the porous membrane 10, which is formed by melting and curing the thermoplastic resin forming the housing 20.

[0085] Thermoplastic resins may also contain additives such as glass fibers. When thermoplastic resins contain additives, the content of the additives can be in the range of 15-45% by mass, or in the range of 20-40% by mass.

[0086] Examples of thermoplastic resins include polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), polyamide 6 (PA6), polyamide 66 (PA66), ABS, and ASA.

[0087] The shell 20 can be formed of PP or PBT. The shell 20 can also be formed of PP with glass fibers incorporated or PBT with glass fibers incorporated. For example, when the shell 20 is formed of PP with glass fibers incorporated, the weld strength S of the porous membrane 10 can be in the range of 2.5 N or more and 30 N or less. For example, when the shell 20 is formed of PBT with glass fibers incorporated, the weld strength S of the porous membrane 10 can be in the range of 1.5 N or more and 25 N or less.

[0088] The housing 20 includes the housing of the vehicle-mounted component. The housing 20 is preferably the housing of the vehicle-mounted component. As described above, it is preferable to join the porous membrane 10 to the housing 20 by welding on the housing of the vehicle-mounted component. According to the venting structure 100, the weld strength of the porous membrane 10 relative to the housing 20 of the vehicle-mounted component can be improved.

[0089] [Manufacturing method of ventilated structure]

[0090] The manufacturing method of the ventilation structure 100 will be described below. The ventilation structure 100 can be manufactured, for example, by the following method.

[0091] First, a circular porous membrane 10 is disposed on the housing 20 having a circular opening 21, such that the opening 21 is sealed. Next, using... Figure 3 The welding device 50 shown uses a welding joint 51 to ultrasonically weld the porous membrane 10 to the housing 20. As a result, a ventilated structure 100 can be obtained.

[0092] [Example]

[0093] The present invention will now be described in more detail through examples. The present invention is not limited to the examples shown below.

[0094] The average thickness, average node area, and Gryllium permeability of the porous membrane were determined using the methods described above.

[0095] [Fabrication of porous membranes]

[0096] (Example 1)

[0097] 20 parts by weight of liquid lubricant (n-dodecane, manufactured by Nippon Energy Corporation) were uniformly mixed with 100 parts by weight of PTFE micropowder (Polyflon F-104, manufactured by Daikin Industries, Ltd.). The mixture was compressed into a barrel and extruded using a plunger extruder. This yielded a sheet-shaped body extending in a predetermined direction. The sheet-shaped body, containing the liquid lubricant, was passed through metal calendering rolls and calendered to a thickness of 260 μm. The liquid lubricant was removed by heating the sheet-shaped body to 150°C, and then the sheet-shaped body was dried. Next, the sheet-shaped body was stretched at 380°C along its length at a ratio of 3.7. The stretching was performed only once along the length direction. This yielded the PTFE porous membrane of Example 1. The PTFE porous membrane of Example 1 has the average thickness, average nodal area, and Glycol permeability shown in Table 1.

[0098] [Example 2]

[0099] A sheet-shaped body with a thickness of 260 μm was calendered and stretched along its length at a ratio of 4.2 at 380°C. Otherwise, the PTFE porous membrane of Example 2 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 2 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0100] [Example 3]

[0101] A sheet-shaped body with a thickness of 200 μm was calendered and stretched at 380°C along its length at a ratio of 3.0. Otherwise, the PTFE porous membrane of Example 3 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 3 has the average thickness, average nodal area, and Gryllium permeability shown in Table 1. Figure 5 The image shows a cross-sectional SEM image (magnification: 1000x) of the PTFE porous membrane of Example 3. Figure 5 As shown, the PTFE porous membrane of Example 3 has a structure in which the nodes are connected in the elongation direction of the original fibers.

[0102] [Example 4]

[0103] A sheet-shaped body with a thickness of 240 μm was calendered and stretched at 380°C along its length at a ratio of 3.0. Otherwise, the PTFE porous membrane of Example 4 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 4 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0104] [Example 5]

[0105] A sheet-shaped body with a thickness of 240 μm was calendered and stretched at 380°C at a ratio of 4.0 along its length. Otherwise, the PTFE porous membrane of Example 5 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 5 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0106] [Example 6]

[0107] A sheet-shaped body with a thickness of 240 μm was calendered and stretched at 380°C at a ratio of 5.0 along its length. Otherwise, the PTFE porous membrane of Example 6 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 6 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0108] [Example 7]

[0109] A sheet-shaped body with a thickness of 240 μm was calendered and stretched at 380°C at a ratio of 6.0 along its length. Otherwise, the PTFE porous membrane of Example 7 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 7 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0110] [Example 8]

[0111] A sheet-shaped body with a thickness of 300 μm was calendered and stretched at 380°C along its length at a ratio of 3.0. Otherwise, the PTFE porous membrane of Example 8 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 8 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0112] [Example 9]

[0113] A sheet-shaped body with a thickness of 300 μm was calendered and stretched at 380°C along its length at a ratio of 6.0. Otherwise, the PTFE porous membrane of Example 9 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 9 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0114] [Example 10]

[0115] A sheet-shaped body with a thickness of 280 μm was calendered and stretched at 380°C at a ratio of 5.2 times along its length. Otherwise, the PTFE porous membrane of Example 10 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 10 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0116] [Example 11]

[0117] A sheet-shaped body with a thickness of 450 μm was calendered and stretched at 380°C at a ratio of 5.0 along its length. Otherwise, the PTFE porous membrane of Example 11 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 11 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0118] [Example 12]

[0119] A sheet-shaped body with a thickness of 400 μm was calendered and stretched along its length at a ratio of 4.2 at 380°C. Otherwise, the PTFE porous membrane of Example 12 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 12 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0120] [Example 13]

[0121] A sheet-shaped body with a thickness of 280 μm was calendered and stretched at 380°C along its length at a ratio of 3.2. Otherwise, the PTFE porous membrane of Example 13 was obtained by the same method as in Example 1. The PTFE porous membrane of Example 13 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0122] [Comparative Example 1]

[0123] A sheet-shaped body with a thickness of 200 μm was calendered and stretched at 380°C at a ratio of 10 times along its length. Otherwise, the PTFE porous membrane of Comparative Example 1 was obtained by the same method as in Example 1. The PTFE porous membrane of Comparative Example 1 has the average thickness, average nodal area, and Grylls permeability shown in Table 1.

[0124] Using the methods described above, the weld strength of shell A formed from PP incorporating 30% by mass glass fiber and shell B formed from PBT incorporating 30% by mass glass fiber were evaluated for the porous membranes of Examples 1-13 and Comparative Example 1. A Herrmann HiQ DILOG (frequency: 35 kHz) was used as the welding apparatus for ultrasonic welding. An Autograph AG-X plus (5 kN) manufactured by Shimadzu Corporation was used as the tensile testing machine for determining the weld strength. The evaluation results are shown in Table 1 below.

[0125] [Table 1]

[0126] As shown in Table 1, the porous membranes of Examples 1-13 exhibit high weld strength ranging from 1.5 N to 30 N. The weld strength of the porous membranes of Examples 1-13 relative to shell A is in the range of 2.5 N to 30 N. The weld strength of the porous membranes of Examples 1-13 relative to shell B is in the range of 1.5 N to 25 N. In contrast, the weld strength of the porous membrane of Comparative Example 1 is lower, at 0.8 N or less.

[0127] The average node area of ​​the porous membranes in Examples 1-13 exceeds 100 μm. 2 And 500μm 2 The following range, and the average thickness is in the range of 120 μm or more and 350 μm or less. Based on the comparison between the porous membranes of Examples 1-13 and the porous membrane of Comparative Example 1, it is inferred that the average node area is greater than 100 μm. 2 And it is 500μm 2 Within the following ranges, and with an average thickness between 120 μm and 350 μm, it is easy to achieve a weld strength S between 1.5 N and 30 N.

[0128] Industrial applicability

[0129] The technologies disclosed in this specification can be applied to various electronic devices such as ECUs (electronic control units), lights, motors, various sensors, pressure switches, actuators, etc.; wearable devices such as smartwatches; various cameras; communication devices such as mobile phones and smartphones; and sensor devices.

Claims

1. A ventilated structure, comprising: The shell has an opening; and A porous membrane is ultrasonically welded to the housing in a manner that seals the opening. The porous membrane has a first main surface facing the opening and a second main surface facing the side opposite to the opening. When the maximum stress when the pressing pin is pressed from the first main surface side of the porous membrane is defined as the weld strength of the porous membrane, the weld strength of the porous membrane is in the range of 1.5N or more and 30N or less.

2. The ventilation structure according to claim 1, wherein, The porous membrane comprises fibrils and nodes connected to the fibrils. The average node area of ​​the porous membrane is greater than 100 μm. 2 And 500μm 2 The following range.

3. The ventilation structure according to claim 1 or 2, wherein, The ventilated structure has: a first region containing the housing and the porous membrane, including a welded portion formed between the housing and the porous membrane; and a second region where the housing is absent and the porous membrane is exposed. The average thickness of the porous membrane in the second region is in the range of more than 120 μm and less than 350 μm.

4. The ventilation structure according to claim 1 or 2, wherein, The gravimetric permeability of the porous membrane is in the range of 3 seconds / 100 mL or more and 40 seconds / 100 mL or less.

5. The ventilation structure according to claim 1 or 2, wherein, The shell is formed of thermoplastic resin.

6. The ventilation structure according to claim 1 or 2, wherein, The housing includes the housing of vehicle-mounted components.

7. A porous membrane, wherein the weld strength determined by the following weld strength test is in the range of 1.5 N or more and 30 N or less. The test for determining the weld strength is as follows: A sample body is fabricated by ultrasonically fusing the porous membrane onto a shell with an opening to seal the opening. In the sample body, the porous membrane has a first main surface facing the opening and a second main surface facing the side opposite to the opening. For the sample body, the maximum stress when the pressing pin is pressed from the first main surface side of the porous membrane is measured, and the measured value is set as the weld strength of the porous membrane.

8. The porous membrane according to claim 7, wherein, The porous membrane comprises fibrils and nodes connected to the fibrils. The average node area of ​​the porous membrane is greater than 100 μm. 2 And 500μm 2 The following range.

9. The porous membrane according to claim 7 or 8, wherein, The average thickness of the porous membrane is in the range of more than 120 μm and less than 350 μm.

10. The porous membrane according to claim 7 or 8, wherein, The gravimetric permeability of the porous membrane is in the range of 3 seconds / 100 mL or more and 40 seconds / 100 mL or less.

11. The porous membrane according to claim 7 or 8, wherein, The porous membrane is used as a ventilation membrane for vehicle components.

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