WO2024117135A1 - 内圧保持性能を高めたエアバッグ及びその製法 - Google Patents

内圧保持性能を高めたエアバッグ及びその製法 Download PDF

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Publication number
WO2024117135A1
WO2024117135A1 PCT/JP2023/042581 JP2023042581W WO2024117135A1 WO 2024117135 A1 WO2024117135 A1 WO 2024117135A1 JP 2023042581 W JP2023042581 W JP 2023042581W WO 2024117135 A1 WO2024117135 A1 WO 2024117135A1
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WIPO (PCT)
Prior art keywords
airbag
base fabric
film
protective material
surface layer
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Ceased
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PCT/JP2023/042581
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English (en)
French (fr)
Japanese (ja)
Inventor
拓海 壁谷
達夫 田中
己行 伊東
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Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Application filed by Asahi Kasei Corp, Asahi Chemical Industry Co Ltd filed Critical Asahi Kasei Corp
Priority to JP2024561514A priority Critical patent/JP7846250B2/ja
Publication of WO2024117135A1 publication Critical patent/WO2024117135A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/02—Occupant safety arrangements or fittings, e.g. crash pads
    • B60R21/16—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags
    • B60R21/23—Inflatable members
    • B60R21/231—Inflatable members characterised by their shape, construction or spatial configuration

Definitions

  • the present invention relates to an airbag used in an airbag device mounted on a vehicle. More specifically, the present invention relates to an airbag having improved internal pressure retention performance, in which the outer edges of a pair of base fabric panels are sewn together, and to a method for manufacturing the same.
  • airbags used in airbag devices mounted on vehicles are made by sewing (stitching) the outer edges of a pair of base fabric panels together to form a bag-like shape, into which gas is instantly injected to inflate and deploy.
  • sewing is usually done using sewing thread, gas leakage between the pair of base fabric panels and through the holes in the sewing needle is unavoidable.
  • Airbags absorb impacts on the human body by retaining injected gas.
  • DABs meet performance requirements if they can handle instantaneous impacts (first impacts).
  • CABs must maintain the inflated state of the airbag even while the vehicle is rolling over after the first impact, and are required to maintain a constant pressure (e.g., 30 kPa) or higher (i.e., internal pressure maintenance) within the airbag for a long period of time (e.g., six seconds).
  • a constant pressure e.g. 30 kPa
  • internal pressure maintenance i.e., internal pressure maintenance
  • pedestrian airbags require internal pressure maintenance for a longer period of time than DABs, because the timing at which a pedestrian lands on the bonnet and hits the vehicle body (e.g., the pillar section) varies.
  • One method is to bond the outer edges of a pair of base fabric panels with only an adhesive instead of sewing. Although this method can prevent gas leakage, there is a risk that the adhesive will not be able to withstand the strength required for the airbag to deploy because there is no sewing.
  • Another method is to manufacture a pair of base fabric panels using the One Piece Woven method and then coat the outside of the base fabric. With this method, there are no stitching and the coating means there is no problem with airtightness, and there is no problem with strength either, but it is difficult to create complex shapes, the coating needs to be applied relatively thickly, and the airbag tends to be heavy and expensive.
  • Another method is to bond the outer edges of a pair of base fabric panels with a silicone adhesive and then sew the bonded portion.
  • This method can ensure strength while suppressing gas leakage, but it has problems such as low productivity, thick bonded portions, and poor folding and storage properties of the airbag.
  • the weight of the silicone adhesive increases the weight of the airbag. As illustrated in FIG. 2, in this method, the silicone adhesive stretches during airbag deployment, preventing gas from accessing the stitching.
  • silicone adhesives are suitable for such applications because of their high adhesive strength with base fabric panels, but the adhesive takes half a day to about a day to harden, resulting in low productivity, and for example, under certain conditions, the folded thickness of a pair of base fabric panels is 2.2 mm at the location where there is no adhesive (location where internal pressure does not need to be maintained), whereas the folded thickness at the location where there is adhesive and stitching is 5.2 mm, resulting in a lack of compactness (foldability, storability). Furthermore, silicone adhesives must be separated from the airbag fabric when recycled, and they emit a relatively large amount of GHG (Green House Gas) during production, so they are not environmentally friendly in the manufacture and disposal of airbags.
  • GHG Green House Gas
  • Patent Document 1 describes an airbag device having a protective cloth sewn along a seam where a pair of opposing portions of a base fabric are sewn together, at a position away from the seam so as to cover the seam from the inside where gas from the inflator is introduced (see Figures 2 and 7 of the same document).
  • Patent Document 1 discloses a protective material for the seam, but this protective material is fixed to the base fabric by sewing, not by adhesion. The purpose of this protective material is to prevent the seam from being directly exposed to the high-pressure gas from the inflator and being destroyed, and to distribute tension in the protective material's seam to prevent damage to the seam of the pair of base fabrics, but is not intended to maintain internal pressure without damaging the seam.
  • Patent Document 2 discloses an airbag having walls including a laminate material, the laminate material including a backing layer having a breathable sheet-like structure made of a woven or knitted fabric, at least two layers of coextruded polymer film, a first polymer layer having a predetermined glass transition temperature on the backing layer side, and a second polymer layer having a predetermined storage modulus on the opposite side to the backing layer, the airbag having walls bonded together such that the second polymer layer is bonded at the edge of the airbag, and a manufacturing method for bonding the first polymer layer and the second polymer layer by applying different thermal energies to them.
  • 5,399,633 is to provide an airbag which can be produced at low cost and which is easy and reliable to seal (see Figs. 1-3 of the same document).
  • Patent Document 2 does not disclose any protective material for the seams of the airbag, and the manufacturing method therefor is primarily intended to increase productivity, not to maintain internal pressure.
  • Patent Document 3 describes an airbag in which panels are joined together at joints, the panels having a woven fabric and a synthetic resin film bonded to the woven fabric via an adhesive, the panels are joined together by pressurizing and heating with a hot melt adhesive sheet interposed between the panels, and the synthetic resin film is disposed on the outside of the airbag.
  • the object of the invention described in Patent Document 3 is to provide an airbag in which the strength of the seams between the panels is high, the durability is excellent, gas leakage is prevented, and handling is easy (see Figures 3 and 4).
  • Patent Document 3 does not describe a method for preventing gas leakage from stitching holes due to stress being applied to the joints between the panels when the adhesive surface around the outer periphery of the airbag is stressed during deployment, which may cause the adhesive to break.Furthermore, there is no mention of the technical idea of adhering a protective material for the stitching to the base fabric at a location separate from the stitching, and maintaining the adhesion between the protective material and the base fabric to maintain the internal pressure.
  • the problem that the present invention aims to solve under such conventional technology is to provide an airbag having excellent compactness while improving internal pressure retention by forming an airtight structure in an airbag in which a pair of base fabric panels are sewn together at their outer periphery to form a bag body, and by bonding the outer surfaces of both ends of a strip-shaped non-breathable protective material to the inner surface of each of the pair of base fabric panels in a bonding region of a predetermined width along the stitching from near the stitching toward the inside of the bag body, and by maintaining this structure even when the airbag is deployed, the airbag has excellent compactness while improving internal pressure retention performance, and a method for manufacturing the same.
  • the present invention is as follows.
  • An airbag comprising at least one pair of base fabric panels sewn together at their outer periphery, an airbag in which both end outer surfaces of a folded, band-like non-breathable film-like protective material are bonded to the inner surface of each of the pair of base fabric panels in a straight or curved line in an adhesive region along the seam of a predetermined width having a proximal end and a distal end from near the seam toward the inside of the bag body, the folded, band-like non-breathable film-like protective material being a laminated resin film of two or more layers including a first surface layer and a second surface layer, the first surface layer being welded to the base fabric panel, but the second surface layers being not bonded to each other, or being bonded to each other but causing the second surface layer to peel off when a tensile force is applied to the pair of base fabric panels when the airbag is deployed.
  • a method for manufacturing an airbag in which at least a pair of base fabric panels are sewn together at their outer periphery comprising the steps of: a step of sandwiching a non-breathable film-like protective material having a predetermined width and made of a laminated resin film having two or more layers including a first surface layer and a second surface layer, between the inner surfaces of the pair of base fabric panels along the outer periphery of the pair of base fabric panels, the non-breathable film-like protective material having a shape conforming to the shape of the base fabric panels and being in a half-folded strip shape; a welding step of applying heat or ultrasonic waves from the outside of the pair of base fabric panels to weld the first surface layer to the inner surface of the base fabric panels, wherein the second surface layers are not welded to each other or are welded to each other but peel off when a tensile force is applied to the pair of base fabric panels when the airbag is deployed; a sewing step of sewing the pair of fabric panels together adjacent the area
  • the airbag and manufacturing method of the present invention have both end outer surfaces of a strip-shaped non-breathable protective material bonded to the inner surface of each of at least a pair of base fabric panels in bonding areas of a predetermined width along the seams, having proximal and distal ends from near the seams toward the inside of the bag, and when a tensile force is applied to the pair of base fabric panels when the airbag is deployed, substantially no tensile force is applied to the bonded areas, thereby maintaining an airtight structure.
  • the airbag has high internal pressure retention performance and excellent compactness, and the manufacturing method for the airbag is highly productive. Therefore, the airbag and the manufacturing method thereof according to the present invention can be suitably used for automobile airbags, CABs and pedestrian airbags which particularly require high internal pressure retention performance.
  • FIG. 1 is a plan view of an airbag according to an embodiment of the present invention in which a pair of base fabric panels are sewn together at their outer periphery to form a bag body.
  • 2 is an explanatory diagram of a state of an airbag when deployed, in a location corresponding to the cross section AA in FIG. 1, in which a portion bonded with a silicone adhesive is sewn.
  • FIG. 4 is an explanatory diagram of a state of a non-breathable protective material in the airbag of the present embodiment when the airbag is deployed.
  • FIG. 4(a) is a first pattern
  • 4(b) is a second pattern (loop outside, film folded back for storage) showing a state in which, when a tensile force is applied between the pair of fabric panels in the airbag of the present embodiment during deployment of the airbag, the length between the distal ends of the folded non-breathable protective material is greater than or equal to the length between the distal ends of the pair of fabric panels, thereby maintaining an airtight structure in the adhesive region.
  • FIG. 2 is an explanatory diagram showing the relationship between a resin constituting a first surface layer and a resin constituting a second surface layer of a laminated resin film which is a band-shaped non-breathable film-like protective material.
  • FIG. 1 is an explanatory diagram of a method for winding a multi-layer film in a two-ply state around a 3-inch paper tube by an inflation method using a multi-layer circular die.
  • FIG. 1 is an explanatory diagram of a method for producing a laminated (base) fabric by using a laminator to bond a multilayer film to a silicone rubber roll so that the multilayer film is in contact with the silicone rubber roll.
  • This is an explanatory diagram of a case where a non-breathable protective material is produced and bonded by laminating two protective materials cut into the base fabric panel shape (horseshoe shape) shown in Figure 1.
  • FIG. 1 is an explanatory diagram of an example of an airbag (cushion) including an isolated sewn portion (in the center) of a closed space.
  • 10 is an explanatory diagram of one method of adhering a folded film to an isolated sewn portion of a closed space.
  • FIG. FIG. 13 is an explanatory diagram of the sealing state according to the method 1 shown in FIG. 12 .
  • 13A and 13B are explanatory diagrams of another method for adhering a folded film to an isolated sewn portion of a closed space and a sealed state.
  • FIG. 2 is an explanatory diagram of an example of a method for producing a half-folded non-breathable film-like protective material (winding up a half-folded film).
  • FIG. 13 is an explanatory diagram of a state in which a wound, half-folded non-breathable film-like protective material is supplied to a heat welding location.
  • FIG. 2 is an explanatory diagram of the layer structure of a folded film in terms of the melting point difference (left side) and the interlayer SP value difference (right side).
  • One embodiment of the present invention is an airbag comprising at least one pair of base fabric panels sewn together at their outer periphery,
  • the airbag has two outer surfaces, both ends of a folded, band-like, non-breathable film-like protective material, bonded in a straight or curved line to the inner surface of each of the pair of base fabric panels in an adhesive region along the seam of a predetermined width having a proximal end and a distal end from near the seam toward the inside of the bag body, and the folded, band-like, non-breathable film-like protective material is a laminated resin film of two or more layers including a first surface layer and a second surface layer, and the first surface layer is welded to the base fabric panel, but the second surface layers are not bonded to each other, or are bonded to each other, but the second surface layer peels off when a tensile force is applied to the pair of base fabric panels when the airbag is deployed.
  • the pair of base fabric panels is not particularly limited and may be a plain weave fabric of polyamide or polyester that is normally used as a base fabric for airbags.
  • the fineness of the fibers constituting the base fabric used in this embodiment is preferably 150 to 900 dtex.
  • a fineness of 150 dtex or more can provide the strength required for an airbag, and a fineness of 900 dtex or less can provide a soft base fabric for an airbag.
  • the fiber When the fiber is in this range, it is flexible when used as a base fabric for an airbag and has a high deployment speed.
  • the weaving density of the base fabric used in the present invention is preferably 30 to 90 threads/inch in both warp and weft directions, and the cover factor is preferably 1500 to 2500.
  • the base fabric panel is coated with a resin on one or both sides thereof or laminated with a single-layer or multi-layer film.
  • the resin used for the resin coating may be a silicone-based or polyurethane-based coating, or a method of thermal lamination using a flame-retardant thermoplastic resin film, etc. may be adopted.
  • the coating amount is preferably 5 to 50 g/m 2.
  • the thickness of the film is preferably 0.001 mm or more and 0.5 mm or less.
  • the airbag according to this embodiment may be one in which a pair of base fabric panels are sewn together at their outer peripheries to form a bag, as shown in Fig. 1.
  • reference numeral 2 indicates the sewn (stitched) portion of the main panel
  • reference numeral 4' indicates the position of the inner edge (top of the loop) of a semi-folded non-breathable protective material, which is on the back side of the front base fabric panel and will be described below.
  • an inner tube reference numeral 23
  • reference numeral 23 which is usually made of base panels of the same material and is cylindrical, can be inserted into the opening, and when the airbag is inflated and deployed, gas is instantly injected into the airbag from inside the inner tube.
  • the stitching is not particularly limited as long as it is not broken when the airbag is inflated and deployed, but it is preferably machine-sewn with sewing thread made of multifilament fiber of the same material as the base fabric panel. As described above, in order to maintain the internal pressure, it is required that the stitching does not break when the airbag is deployed and that there is substantially no gas leakage.
  • the sewing thread may be a single twisted fiber or a multiple twisted fiber having two or more single twisted fibers twisted together, and the total fineness of the twisted fibers is preferably 700 to 2000 dtex.
  • the sewing method may be a lock stitch, a chain stitch, etc.
  • the number of stitches (stitch pitch) is preferably 30 to 60 stitches/10 cm.
  • FIG. 2 is an enlarged view of the area corresponding to the A-A cross section in Fig. 1 to prevent gas leakage at the seams, and explains the state of an airbag when it is deployed if it is sewn to the area bonded with silicone adhesive in the conventional technology.
  • silicone adhesive When silicone adhesive is used, the silicone adhesive deforms and stretches during deployment to seal in the gas, improving the internal pressure retention, but the thickness of the silicone adhesive after curing increases the thickness of the airbag after folding (when stored), making it difficult to store, and it takes a long time, from half a day to about a day, to cure, reducing the productivity of the airbag.
  • the outer surfaces of both ends of a strip-shaped non-breathable film-like protective material are bonded in a straight or curved line to the inner surface of each of a pair of base fabric panels in an adhesive region of a predetermined width along the seam from near the seam toward the inside of the bag body, the non-breathable film-like protective material being a laminated resin film of two or more layers including a first surface layer and a second surface layer, the first surface layer being welded to the base fabric panel, but the second surface layers being not bonded together, or being bonded together but the second surface layer peeling off when a tensile force is applied to the pair of base fabric panels when the airbag is deployed.
  • the structure having such a feature may be used in the entire outer periphery of the airbag, or in a part of the airbag.
  • a part means, for example, 50% or more.
  • a silicone adhesive may be used in the stitching part of the airbag where other gas leakage may occur, in order to obtain airtightness of the entire airbag.
  • the structure having such a feature may be applied in the vicinity of the stitching of any two (a pair) of the base fabric panels of the airbag composed of at least two or more base fabric panels.
  • the pair of base fabric panels do not necessarily have to have the same shape, and may be three-dimensionally sewn in which the shapes of the stitching lines between the pair of base fabric panels are different, as long as the airtightness of the adhesive region is not impaired.
  • an airbag formed by sewing at least one pair of fabric panels together at their outer periphery refers to an airbag in which the fabric panels are sewn together to form an inflation chamber of the airbag, and in which two or more fabric panels are sewn together at the outer periphery of the chamber. Therefore, the airbag is not limited to an airbag composed of only two fabric panels, which are made by overlapping two fabric panels of the same shape, as shown in Figures 1 and 15, and there is no limit to the number of fabric panels that make up the airbag or the overall structure of the airbag, as long as there is a portion where two or more fabric panels are joined together at the outer periphery of the chamber.
  • this broadly includes a single, line-symmetrical base fabric panel that is folded along the line of symmetry and the overlapping portions sewn together, a single, strip-shaped base fabric panel that is rolled into a tube and the overlapping portions sewn together, and three or more base fabric panels that are sewn together, that is, as long as the partial structure has a non-breathable protective material covering the sewn portions of the base fabric panels.
  • non-breathable refers to the surface property of a protective material that suppresses ventilation to a degree that does not significantly impair the airtightness of the airbag.
  • the amount of gas passing through the surface is preferably 0.5 L/ dm2 /min or less, more preferably 0.1 L/ dm2 /min or less, and even more preferably 0.05 L/ dm2 /min or less.
  • Figure 3 illustrates the state of the half-folded non-breathable film protective material when the airbag is deployed.
  • the half-folded non-breathable film protective material forms a loop shape toward the inside of the airbag and forms an airtight structure in the adhesive area with the base fabric panel, thereby maintaining internal pressure.
  • the length between the distal ends along the folded film-like non-breathable protective material is greater than or equal to the length between the distal ends along a pair of base fabric panels when the airbag is deployed, thereby maintaining an airtight structure in the adhesive region. That is, as shown in Figures 4(a) and 4(b), since the loop-shaped protective material has a sufficient length, when the airbag is deployed and pulled horizontally from the seam, substantially no force is applied to the adhesive region between the protective material and the base fabric panel, and there is no peeling or destruction in the adhesive region, so that airtightness is maintained.
  • the non-breathable protective material has high extensibility, even if the length of the loop of the protective material before the airbag is deployed (when the airbag is housed) is approximately the same as or shorter than the adhesive distance along the base fabric panels, the non-breathable protective material is stretched by the tensile force applied when the airbag is deployed, and the seam is destroyed first, substantially no force is applied to the adhesive region, resulting in the same result.
  • the state of the airbag when it is deployed can be simulated by, for example, using the following method. First, the stored airbag is taken out, a part of the protective material and the base fabric panel are cut, and the pair of base fabric panels are spread 180° as shown in the deployed state in Figures 4(a) and (b).
  • Figure 4(a) is the first pattern
  • Figure 4(b) is the second pattern (loop outside, film folded back and stored).
  • the length between the distal ends along the half-folded film-like non-breathable protective material is greater than or equal to the length between the distal ends along the pair of base fabric panels, thereby maintaining an airtight structure in the adhesive region.
  • half-folded (film-like) non-breathable protective material refers not only to a material that is in a half-folded state when stored in an airbag, as shown in the upper part of Figures 4(a) and (b), i.e., a strip-shaped single-layer or multi-layer resin film that is half-folded, but also to a material that is folded multiple times, such as into an accordion-like shape, and to a material in which two strip-shaped (including curved) single-layer or multi-layer resin films are layered together and one end is bonded or welded with an adhesive (i.e., a material produced by laminating two sheets together).
  • an adhesive i.e., a material produced by laminating two sheets together.
  • Such a belt-like semi-folded non-breathable film-like protective material may be adhered to the base fabric in a straight or curved line along the seam, or may be prepared by using two pieces of resin film cut into a desired shape, overlapping the outer layers of one end (inner edge side) of the multilayer film together (for example, in the case of a PE (second surface layer)-PA6/12 (first surface layer) multilayer film, a part of the second surface layer is peeled off and the first surface layers are overlapped together), and welding the pieces together along the inner edge so that the length from the outer edge is a predetermined length, for example, a width of 5 mm, or by bonding them together with, for example, a cyanoacrylate-based instant adhesive (manufactured by Konishi Co., Ltd.), and thoroughly drying (i.e., not in a belt shape, but for example, by bonding two pieces of protective material cut into the base fabric panel shape (horseshoe shape) shown in FIG.
  • the non-breathable film-like protective material there are no particular limitations on the non-breathable film-like protective material, so long as it is not destroyed when the airbag is inflated and deployed, and single-layer or multi-layer resin films can be used. From the viewpoint of reducing the weight and compactness (ease of folding and storage) of the airbag, it is preferable to use single-layer or multi-layer resin films as the non-breathable protective material.
  • the adhesive strength can be increased and the internal pressure retention of the airbag can be improved by bonding the same type of single-layer or multi-layer resin film to a laminated base fabric panel.
  • recyclability can be improved by using the same type of single-layer or multi-layer resin film (and substrate) used in the non-breathable film-like protective material and the base fabric panel.
  • the term “bonding” includes bonding with an adhesive and welding with ultrasonic waves or heat.
  • the base fabric panel and the protective material can be bonded together by welding using heat or ultrasonic waves to form a bonded area that will not peel off even when the airbag is deployed and can maintain airtightness. Welding without using adhesives is preferable from the standpoint of thickness after folding, productivity, recycling, etc.
  • the term "bonded regions (5, 5')" have proximal ends (6, 6') and distal ends (7, 7') with respect to the seam (2), respectively.
  • the proximal ends (6, 6') may be located on the inside of the airbag from the seam (2) or on the outside of the airbag (not shown). In the latter case, the bonded regions will extend to the seam allowance.
  • the loop structure of the half-folded non-breathable protective material in the adhesive region may be arranged to face the outer edge of the airbag (the outside of the airbag).
  • the half-folded non-breathable protective material assumes a loop shape toward the inside of the airbag, and the length between the distal ends along the half-folded non-breathable protective material becomes larger than the length between the distal ends along a pair of base fabric panels, so that an airtight structure can be formed in the adhesive region with the base fabric panels.
  • the "adhesive region" only needs to be adhered in a manner that will not break or peel off when the airbag inflates and deploys, and will maintain airtightness and internal pressure retention. Adhesion can be improved by adjusting the material of the protective material and the welding conditions.
  • the thickness of the non-breathable film-like protective material is preferably 0.001 mm or more and 0.5 mm or less, more preferably 0.001 mm or more and 0.1 mm or less, and even more preferably 0.005 mm or more and 0.05 mm or less, from the viewpoint of the folded thickness.
  • the adhesive strength (peel strength) in the adhesive region between the base fabric panel and the non-breathable film-like protective material is preferably 1 N/cm or more, and more preferably 3 N/cm or more, from the viewpoint of airtightness. If the adhesive strength is 3 N/cm or more, the occurrence of leaks caused by the film peeling off from the base fabric panel due to the wind pressure of the gas when the airbag is deployed is significantly reduced.
  • the tensile modulus of the semi-folded band-shaped non-breathable protective material is preferably 100 to 800 MPa in both MD (machine direction) and TD (transverse direction), more preferably 150 to 600 MPa, and even more preferably 200 to 500 MPa.
  • the tensile modulus of the film referred to here is the measurement result when the band-shaped non-breathable film-like protective material is opened from the half-folded state and pulled.
  • the above tensile modulus (flexibility) makes it easy to form a curved structure to follow the curved parts (including R parts and reverse R parts) that are usually used in the main fabric of an airbag.
  • the film By setting the tensile modulus to 100 to 800 MPa, the film has good handleability (balance between ease of deformation at curved parts and handling of the film) due to moderate flexibility.
  • the tensile breaking strength of the film is preferably 10 to 100 MPa in both MD and TD, more preferably 15 to 80 MPa, and even more preferably 20 to 60 MPa. By setting the tensile breaking strength to 100 MPa or less, the film will have low rigidity and good handleability.
  • the airbag of this embodiment may have an R portion with a radius of curvature of 300 mm or less and/or an inverse R portion with a radius of curvature of 300 mm or less in the adhesive region, as shown in Figs. 1 and 11.
  • the R portion is a portion of the seam line along the outer periphery of the base fabric panel that has a curved shape that is convex toward the side other than the inflatable portion (chamber) of the airbag.
  • the X portion in Fig. 1 corresponds to this.
  • the inverse R portion is a portion of the seam line along the outer periphery of the base fabric panel that has a curved shape that is convex toward the inflatable portion (chamber) of the airbag.
  • the Y portion in Fig. 1 corresponds to this.
  • wrinkles are more likely to occur when the non-breathable protective material is adhered along the seam line than in straight seams, and tension is more likely to be applied to the sewn portion when the airbag is deployed.
  • the degree of wrinkles when the non-breathable protective material is adhered can be confirmed by measuring the step (peak-valley difference) between the wrinkled portion and the normal portion.
  • the step (peak-valley difference) between the wrinkled portion and the normal portion of the R portion is preferably 400 ⁇ m or less, more preferably 300 ⁇ m or less, even more preferably 200 ⁇ m or less, and even more preferably 100 ⁇ m or less.
  • the step between the wrinkled portion and the normal portion can be reduced to prevent stress concentration, gas leakage from the adhesive portion can be suppressed, and an airbag with excellent storage capacity can be obtained.
  • the ratio (R portion/straight portion) of the step (peak-valley difference) between the wrinkled portion and the normal portion of the R portion to the step (peak-valley difference) between the wrinkled portion and the normal portion of the approximately straight portion excluding the R portion is preferably 0.6 to 2.0, and more preferably 0.8 to 1.5.
  • the wrinkle step measurement was performed using a surface roughness measuring instrument (SURFTEST EXTREME SV-3000CNC) manufactured by Mitutoyo Corporation, and the wrinkled area and the surrounding normal area were measured in three-dimensional mode under the following measurement conditions.
  • An arbitrary cross-section extraction function was used in the obtained three-dimensional image to extract a cross-section that included the largest step area, and a baseline was drawn on the extracted cross-section (two-dimensional) connecting the start point and end point of the wrinkled area (step), and the maximum height from the baseline was determined.
  • the adhesive strength (peel strength) in the adhesive region between the base fabric panel and the non-breathable protective material in the R portion is preferably 1 N/cm or more, more preferably 2 N/cm or more, and even more preferably 3 N/cm or more. If the adhesive strength is 3 N/cm or more, the occurrence of leakage caused by the film peeling off from the panel base fabric due to the wind pressure of the gas when the airbag is deployed is significantly reduced.
  • the adhesive strength (peel strength) in the adhesive region between the base fabric panel and the non-breathable protective material in the R portion referred to here is calculated based on the tensile strength of a test piece obtained by cutting the airbag into a 100 x 30 strip shape perpendicular to the line connecting the two points, as described below in the measurement method of the adhesive strength (peel strength) (N/cm) between the protective material and the panel fabric in the R portion, and the sample is taken from the R portion with a curvature radius of 300 mm or less.
  • the ratio of the adhesive strength at the R portion to the adhesive strength of the substantially straight portion excluding the R portion is preferably 0.5 to 2.5, more preferably 0.7 to 2.0, and even more preferably 0.8 to 1.5.
  • Another embodiment of the present invention is a method for manufacturing an airbag in which a pair of base fabric panels are sewn together at their outer periphery to form a bag, the method comprising the steps of: a step of sandwiching a non-breathable film-like protective material having a predetermined width and made of a laminated resin film having two or more layers including a first surface layer and a second surface layer, between the inner surfaces of the pair of base fabric panels along the outer periphery of the pair of base fabric panels, the non-breathable film-like protective material having a shape conforming to the shape of the base fabric panels and being in a half-folded strip shape; a welding step of applying heat or ultrasonic waves from the outside of the pair of base fabric panels to weld the first surface layer to the inner surface of the base fabric panels, wherein the second surface layers are not welded to each other or are welded to each other but peel off when a tensile force is applied to the pair of base fabric panels when the airbag is deployed;
  • the release paper does not remain in the airbag, so that the weight of the airbag does not increase and the storability does not deteriorate, and the release paper can be prevented from affecting the deployment speed and deployment behavior of the airbag.
  • Such a configuration can be achieved, for example, by setting the melting point of the resin constituting the first surface layer of the laminated resin film, which is a non-breathable film-like protective material folded in half, to be 50°C to 160°C, preferably 60°C to 160°C, lower than the melting point of the resin constituting the second surface layer, so that the second surface layers on the inside of the loop are not welded to each other, or by setting the difference in SP values of the resin constituting the first surface layer, the resin constituting the second surface layer, and the resin constituting the other layers of the laminated resin film, which is a non-breathable film-like protective material folded in half, to be 2.0 [cal/ cm3 ) 1/2 ] or more between adjacent layers, so that delamination occurs between any of the layers, or the second surface layer delaminates from an adjacent layer.
  • the difference in SP value between any adjacent layers is preferably 2.0 [cal/ cm3 ) 1/2 ] or more, more preferably 2.5 [cal/ cm3 ) 1/2 ] or more, even more preferably 3.0 [cal/ cm3 ) 1/2 ] or more, and even more preferably 4.0 [cal/ cm3 ) 1/2 ] or more.
  • the melting point of PA6/12 is 128°C
  • that of TPEE is 216°C
  • that of PA6/66 is 194°C
  • that of PA12 elastomer is 176°C
  • that of PO acid-modified polyethylene
  • that of PE LDPE
  • the difference between the melting points of the resins constituting the first surface layer and the resins constituting the second surface layer can be made 50°C or more.
  • the preferred range of the melting point difference is 50° C. to 160° C., more preferably 60° C. to 160° C., and even more preferably 80° C. to 160° C.
  • the melting point difference 50° C. or more the adhesive strength with the base fabric panel can be increased and fusion between the second surfaces can be made difficult.
  • the melting point of the resin constituting the protective material is preferably 90° C. or higher, more preferably 100° C. or higher, and even more preferably 110° C. or higher. By making the melting point 90° C. or higher, sufficient adhesive strength can be maintained even when the temperature inside the vehicle becomes high.
  • the SP value of PE is 8.1 [cal/cm 3 ) 1/2
  • the SP value of PA6/66 is 13.6 [cal/cm 3 ) 1/2
  • the SP value of PA6/12 is 13.6 [cal/cm 3 ) 1/2
  • the SP value of PET is 10.7 [cal/cm 3 ) 1/2 ]
  • PE (second surface layer)-PA6/66 release layer side of the first surface layer, which is a multilayer film)
  • PE (second surface layer, release layer)-PET (first surface layer) is used as the protective material
  • the difference in SP value with the PA base fabric or PET base fabric, respectively can be made 2.0 [cal/cm 3 ) 1/2 ] or more.
  • the first surface layer (fabric panel side) can be considered to be composed of an adhesive layer (PA6/12), while the second surface layer (inside the loop) can be considered to be composed of four layers including a release layer (PE), an intermediate layer (acid-modified PE), and a high melting point layer (PA6/66).
  • PA6/12 adhesive layer
  • PA6/12 adhesive layer
  • PA6/66 high melting point layer
  • the release effect is achieved not only when the SP value difference between the high melting point layer (PA6/66) and the release layer (PE) is greater than or equal to 2.0 [cal/cm3)1/2, but also when the SP value difference between adjacent layers of the adhesive layer (PA6/12), X layer (e.g., the intermediate layer (acid-modified PE), and the high melting point layer (PA6/66) constituting the first surface layer is greater than or equal to 2.0 [cal/ cm3 ) 1/2 .
  • the above-mentioned configuration based on the SP value difference is preferable to the above-mentioned configuration based on the melting point difference.
  • the reason for this is that the fusion (processing) temperature can be raised above the melting point of the film, making it possible to strengthen the adhesion between the base fabric panel and the film, and by increasing the processing speed, productivity can be improved.
  • the SP value (Hildebrand solubility parameter) is a physical property defined as the square root of the cohesive energy density, and indicates the solubility behavior of a solvent. Therefore, the inventors of this application used combinations with large differences in SP value as an index for selecting the release layer.
  • the SP values of various resins are listed, for example, in "Guide to Various Standards and Usage: Plastic Material Test Methods, Comparisons, Evaluations, and Results” p. 32 (2nd edition, May 10, 2011) by Sangyo Gijutsu Center Co., Ltd., and a reference for calculating the SP value is "Practical Polymers for Engineers" by Kodansha, August 1, 1989.
  • HSP Hansen solubility parameter
  • the HSP value is also shown in the examples, but the peeling effect is achieved by making the HSP value difference 1.0 (cal/ cm3 ) 1/2 ) or more.
  • the HSP value difference is more preferably 2.0 (cal/ cm3 ) 1/2 ) or more, and even more preferably 3.0 (cal/ cm3 ) 1/2 ) or more.
  • HSP is a predicted value by Winmostar (V9.3.0) manufactured by CrossAbility Co., Ltd., and is calculated by the dispersion term ( ⁇ D), polarization term ( ⁇ P), and hydrogen bond term ( ⁇ H) between certain substances.
  • the HSP calculation for the copolymer composition is a value obtained by calculating the HSP of each homopolymer and multiplying it by the composition ratio (volume ratio) to obtain a total value.
  • the glass transition temperature (Tg) of the second surface layer (inside of the loop) is preferably 0°C or higher, more preferably 20°C or higher, and even more preferably 30°C or higher.
  • the upper limit of the glass transition temperature is 80°C or lower, more preferably 70°C or lower, and even more preferably 60°C or lower.
  • An airbag in which at least one pair of base fabric panels are sewn together at their outer periphery, An airbag can be provided with high productivity, in which both end outer surfaces of a folded, band-shaped non-breathable protective material are bonded to the inner surface of each of the pair of base fabric panels in an adhesive region of a predetermined width along the seam from near the seam toward the inside of the bag body, the outer surfaces being bonded in a straight or curved line, the folded non-breathable protective material being a laminated resin film of two or more layers including a first surface layer and a second surface layer, the first surface layer being welded to the base fabric panel, and the second surface layers being not bonded to each other, or being bonded to each other, when a tensile force is applied to the pair of base fabric panels when the airbag is deployed.
  • the airbag of the present embodiment can also be manufactured (provided) with high productivity by using the manufacturing method described below.
  • a method for manufacturing an airbag having at least a pair of base fabric panels sewn together at their outer periphery comprising the steps of: a welding step of continuously sandwiching a semi-folded band-shaped non-breathable film-like protective material made of a laminated resin film of two or more layers including a first surface layer and a second surface layer between the inner surfaces of the pair of base fabric panels while applying tension to the material along the straight or curved outer periphery of the pair of base fabric panels, and welding the surface or the first surface layer of the single-layer resin film to the inner surface of the base fabric panels by applying heat or ultrasonic waves from the outside of the pair of base fabric panels, in which the second surface layers of the laminated resin film are not bonded to each other or are bonded to each other, but the second surface layers peel off when a tensile force is applied to the pair of base fabric panels when the
  • the tensile modulus of the film is preferably 100 to 800 MPa in both MD (machine direction) and TD (transverse direction), more preferably 150 to 600 MPa, and even more preferably 200 to 500 MPa.
  • the tensile modulus of the film referred to here is the measurement result when the band-shaped non-permeable and breathable film-like protective material is opened from a half-folded state and pulled.
  • the above tensile modulus (flexibility) makes it easy to form a curved structure that fits the curved part that is usually used in the main fabric of an airbag.
  • the tensile modulus By setting the tensile modulus to 100 to 800 MPa, the film has moderate flexibility and good handleability (balance between ease of deformation at curved parts and handling of the film).
  • the tensile breaking strength of the film is preferably 10 to 100 MPa in both MD and TD from the viewpoint of durability, more preferably 15 to 80 MPa, and even more preferably 20 to 60 MPa.
  • the tensile breaking strength is 100 MPa or less, the rigidity is suppressed and the film has good handling properties. Furthermore, when the band-shaped non-permeable and breathable film-like protective material is deformed to follow the curved outer peripheral edge by applying tension, it is preferable to use a thermoplastic resin film, since the film can be easily stretched by applying heat.
  • examples of the method of sandwiching a strip-shaped non-breathable film-like protective material along the straight or curved outer peripheral edges of a pair of base fabric panels include a method of preparing a roll of wound up semi-folded film in advance and sending the strip-shaped non-breathable film-like protective material from the wound roll to the welding point by heat welding or ultrasonic welding, as exemplified in Figures 15 to 17, a method of preparing a roll of wound up the strip-shaped non-breathable film-like protective material in an unfolded state in advance and folding the strip-shaped non-breathable film-like protective material in half during the process of sending it from the wound roll to the welding point by heat welding or ultrasonic welding, and then sending it to the welding point, and a method of folding a strip-shaped non-breathable film-like protective material that has been cut in advance to the length of the straight or curved outer peripheral edges of a pair of base fabric panels in half and sending it to the welding point by heat welding or ultrasonic welding, with the first method being
  • the pleats in the folded portion can be firmly fixed, and by continuously feeding the film from the wound roll, the folded portion of the film is less likely to shift, and warping of the folded film is suppressed (as the film structure is symmetrical between the top and bottom), which is expected to have the further effect of suppressing the occurrence of wrinkles (improving quality).
  • the method of applying tension to the half-folded film is not particularly limited, but for example, a method can be used in which the tape is pulled while adjusting the tension applied to the tape so as to conform to the shape of the outer periphery of the airbag while holding the tape with one hand and the base fabric with the other hand, as shown in Fig. 17.
  • a roll of the half-folded film may be prepared in advance, and a tension control mechanism may be provided in the process of feeding the band-shaped non-breathable film-like protective material from the roll to the welding location by thermal welding or ultrasonic welding.
  • a tension control mechanism may be provided in the process of feeding the band-shaped non-breathable film-like protective material from the roll to the welding location by thermal welding or ultrasonic welding.
  • the base fabric is sandwiched between upper and lower conveyor belts at the welding location, and while the base fabric is transported by the conveyor belt, it is sandwiched between upper and lower hot plates and heat is applied, so that continuous welding can be performed.
  • the tape (sandwiched between the base fabrics) is in a heated state, and the tape is stretched to fit the shape of the outer periphery of the airbag by tension, so that the non-air-permeable and breathable film-like protective material can be bonded without wrinkles even in curved parts including R parts and reverse R parts.
  • a part or the whole of the non-air-permeable and breathable film-like protective material can be preheated by a method such as a hot plate or hot air, so that the tape can be easily stretched to fit the shape of the outer periphery of the airbag.
  • a cooling section using a cooling plate may be provided immediately after welding.
  • the adhesiveness of the non-permeable, breathable film-like protective material is improved.
  • the welding workability of the curved section can be improved.
  • the method of continuously sandwiching the half-folded film (tape) along the straight or curved outer periphery of the pair of base fabric panels while applying tension to the film and applying heat or ultrasonic waves from the outside of the pair of base fabric panels to bond the panels together may lead to misalignment of the base fabrics, as the upper and lower base fabrics are bonded together continuously and simultaneously. Also, in the final stages of bonding or depending on the sewing shape of the airbag, there may be a small space, which may make it difficult to insert the tape under the upper base fabric.
  • the following two-step method may be used, in which, rather than clamping the tape between a pair of base fabric panels, one side of the tape is adhered to the first piece of base fabric (1st step), and then a second piece of base fabric is placed on top of the tape and compressed (2nd step).
  • the tape is fed onto one base fabric panel while applying tension, and then the tape is welded onto the first base fabric by heating from below, fixing the tape onto the one base fabric panel without wrinkles (1st step).
  • a second base fabric is then placed on top of the tape, and pressure is applied by heating using thermal welding or ultrasonic welding (2nd step). This eliminates the need to simultaneously operate the upper and lower base fabrics as described above, and only one base fabric is operated, and because the tape is not sandwiched between the base fabrics, there is no problem with the space becoming narrow at the final stage of bonding, etc.
  • the method of applying tension to the tape is not particularly limited, and a method of pulling the tape while adjusting the tension applied to it so that it conforms to the shape of the outer periphery of the airbag can be used, similar to the above-mentioned tension application and clamping method, while holding the tape with one hand and the base fabric with the other hand.
  • a roll of half-folded film may be prepared in advance, and a tension control mechanism may be provided in the process of sending the band-shaped non-breathable film-like protective material from the roll to the welding point by thermal welding or ultrasonic welding.
  • the tape can be welded onto the first base fabric by a hot plate from below the belt heat pressing machine, while the tape is heated by the upper hot plate to assist in stretching the tape in the R and reverse R sections.
  • the method for placing a second base fabric on the tape and heating it by thermal welding or ultrasonic welding is not particularly limited, and it may be continuously welded using a belt heat pressing machine as in the first step, or it may be welded all at once using a heat press machine that can heat the welded parts simultaneously, but from the viewpoint of productivity, it is preferable to use a heat press machine that can heat the welded parts simultaneously.
  • a secondary effect of improving the processing speed in the first step can be expected by temporarily fixing the welded parts.
  • This structure can be used as a method for intentionally providing a joint portion of a band-shaped non-breathable protective material folded in half when welding a band-shaped non-breathable protective material folded in half near a sewing shape having a branch point or a bent sewing shape, when the airbag size is large and the process is divided from the viewpoint of workability, etc. Moreover, regardless of the tension application or clamping method, it can be widely applied to the 2-step method, the two-sheet bonding method, etc.
  • the multilayer film had a layer structure of "adhesive layer/middle layer/outer layer", and was made of PA6/12 for the adhesive layer, m-PE for the middle layer, and PA6/66 for the outer layer.
  • the film was extruded from a multilayer circular die and an inflation method was used to obtain a 20 ⁇ m thick three-layer film.
  • the adhesive layer was the surface to be laminated to the plain weave base fabric.
  • the laminated PA base fabric used as the base fabric panel was a plain weave fabric woven using nylon 66 multifilament fibers as the warp and weft.
  • the multilayer film and the above-mentioned base fabric were overlapped and bonded using a laminator (see FIG. 9) so that the multilayer film was in contact with the silicone rubber roll side.
  • the lamination conditions were as follows: Temperature: 160°C Roll speed: 0.3 m/min Linear pressure: 2.3 kg/cm.
  • the total fineness of the weaving yarn constituting the obtained base fabric was 470 dtex, the number of filaments was 136, and the weaving density of the base fabric was 49 threads/inch (2.54 cm).
  • Si-coated (base) fabric, non-laminated PA or PET base fabric used in the examples The Si-coated fabric used as the base fabric panel and/or protective material was a plain weave fabric woven using nylon 66 or polyester multifilament fibers as the warp and weft, with one side coated with silicone resin.
  • the total fineness of the weaving yarn constituting the base fabric was 470 dtex, the number of filaments was 136, the weaving density of the coated fabric was 49/inch (2.54 cm), and the amount of silicone resin coated was 25 g/ m2 .
  • a film to be used as a protective material was prepared as follows. As shown in Fig. 8, a multilayer circular die was used to wind a desired multilayer film in a two-ply state around a 3-inch paper tube by the inflation method. At this time, the film was formed so that the inner surface side 1b of the tubular film was the adhesive layer and the outer surface side 1a was the outer layer.
  • the film formation conditions were as follows.
  • the tensile modulus of the film was measured using an Autograph AG-IS (manufactured by Shimadzu Corporation) in an atmosphere of 23°C and 50% RH.
  • the tensile modulus of the film referred to here is the measurement result when a strip-shaped non-permeable and breathable film-like protective material is opened from a half-folded state and pulled, and if the length of the measurement sample is short and the chuck distance cannot be satisfied, the chuck distance may be narrowed. In this case, a tensile speed at which the strain rate is 5%/min is selected.
  • the adhesive used for bonding the sewn portion between the protective material and the main panel was TCS 7770XL/C manufactured by Elkem Japan Co., Ltd.
  • the cartridge was a Mixpack with a capacity of 200cc:200cc. It was loaded into a manual gun DM400-01 manufactured by Tomita Engineering Co., Ltd., and was made to be capable of being injected using a static mixer MC13-12.
  • the internal pressure of the airbag 6 seconds after the solenoid valve was opened was divided by the maximum internal pressure of the airbag after the solenoid valve was opened, and the value was recorded.
  • the test was performed once for each of the three airbags, and the average of the three measurements was calculated as the internal pressure retention rate after six seconds, expressed as a percentage.
  • the change in the internal pressure of the airbags over time was measured.
  • the test was performed once for each of three airbags, and the average of the three measurement results was calculated as the internal pressure retention rate 6 seconds after aging, expressed as a percentage.
  • the main panel used was a PA base fabric that was not laminated.
  • the protective material used was a two-kind two-layer multilayer film with a layer structure of "adhesive layer/outer layer", in which PA6/12 was used for the adhesive layer and PE (LDPE) was used for the outer layer, as exemplified in FIG. 8, and a two-kind two-layer film with a thickness of 20, 30, or 40 ⁇ m was obtained by extrusion from a multilayer circular die and inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the uncoated side on the inside, and a protective material was inserted between them.
  • the protective material and the main panel were welded by the heat welding method 1.
  • the outer periphery was sewn with a sewing thread according to the method for producing the main (base fabric) panel described above.
  • the evaluation results of the airbag using this film are shown in Table 1 below.
  • Example 4 An airbag was produced in the same manner as in Example 2, except that ultrasonic welding was performed instead of heat welding 1. The evaluation results of the obtained airbag are shown in Table 1 below.
  • Example 5 A non-laminated PET base fabric was used as the main panel.
  • the protective material used was a two-kind, two-layer multilayer film with a layer structure of "adhesive layer/outer layer", with PE (LDPE) used for the outer layer and PET used for the adhesive layer.
  • PE (LDPE) was extruded from a multilayer circular die, and a single-layer film with a thickness of 7 ⁇ m was obtained by the inflation method.
  • a two-kind, two-layer multilayer film was produced by thermally laminating the 7 ⁇ m PE single-layer film on a commercially available PET film 38 ⁇ m (Toray Industries, Inc., Lumirror #38-S10).
  • Example 6 A laminated PA base fabric was used as the main panel.
  • the protective material used was a four-kind, four-layer multilayer film with a layer structure of "adhesive layer/intermediate layer 1/intermediate layer 2/outer layer".
  • PA6/12 was used for the adhesive layer
  • PO for the intermediate layer 1
  • PA6/66 for the intermediate layer 2
  • PE PE
  • the film was extruded from a multilayer circular die and a four-kind, four-layer film with a thickness of 30 ⁇ m was obtained by an inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG.
  • the main panel used was a laminated PA base fabric.
  • the protective material used was a three-kind, three-layer multilayer film with a layer structure of "adhesive layer/intermediate layer/outer layer", in which PA6/12 was used for the adhesive layer, PO for the intermediate layer, and PA6 for the outer layer, and extruded from a multilayer circular die to obtain a three-kind, three-layer film with a thickness of 20 ⁇ m by an inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the laminated surface on the inside, and a protective material was inserted between them.
  • the protective material and the main panel were welded by the heat welding method 1.
  • the outer periphery was sewn with a sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 2 The evaluation results of the airbag using this film are shown in Table 2 below.
  • the main panel used was a PA base fabric that was not laminated.
  • the protective material used was a two-kind two-layer multilayer film with a layer structure of "adhesive layer/outer layer", in which PA6/12 was used for the adhesive layer and TPEE-1 was used for the outer layer, and the two-kind two-layer film with a thickness of 20 ⁇ m was obtained by extrusion from a multilayer circular die and inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the uncoated side on the inside, and the protective material was inserted between them.
  • the protective material and the main panel were welded by the method of heat welding 1.
  • the outer periphery was sewn with sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 2 The evaluation results of the airbag using this film are shown in Table 2 below.
  • the main panel used was a laminated PA base fabric.
  • the protective material used was a three-kind, three-layer multilayer film with a layer structure of "adhesive layer/middle/outer layer", in which PA6/12 was used for the adhesive layer, PO for the middle layer, and TPEE-1 for the outer layer, and the film was extruded from a multilayer circular die and a three-kind, three-layer film with a thickness of 30 ⁇ m was obtained by an inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the laminated surface on the inside, and the protective material was inserted between them. The protective material and the main panel were welded by the heat welding method 1.
  • the outer periphery was sewn with a sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 2 The evaluation results of the airbag using this film are shown in Table 2 below.
  • the main panel used was a laminated PA base fabric.
  • the protective material used was a three-kind three-layer multilayer film with a layer structure of "adhesive layer/intermediate/outer layer", in which PA6/12 was used for the adhesive layer, PO for the intermediate layer, and PA6/66 for the outer layer, and extruded from a multilayer circular die to obtain a three-kind three-layer film with a thickness of 30 ⁇ m by the inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked together, and the protective material was inserted between them. The protective material and the main panel were welded by the heat welding method 2.
  • the outer periphery was sewn with a sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 2 The evaluation results of the airbag using this film are shown in Table 2 below.
  • the main panel used was a PET base fabric that was not laminated.
  • the protective material used was a two-kind two-layer multilayer film with a layer structure of "adhesive layer/outer layer", in which TPEE-2 was used for the adhesive layer and TPEE-3 was used for the outer layer, and the two-kind two-layer film with a thickness of 20 ⁇ m was obtained by extrusion from a multilayer circular die and inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the uncoated side on the inside, and the protective material was inserted between them.
  • the protective material and the main panel were welded by the method of heat welding 1.
  • the outer periphery was sewn with sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 2 The evaluation results of the airbag using this film are shown in Table 2 below.
  • the main panel used was a PA base fabric that was not laminated.
  • the protective material used was a single-layer film with a layer structure, and was extruded from a multi-layer circular die using PA6/12, and a single-layer film with a thickness of 30 ⁇ m was obtained by an inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two pieces of base fabric cut into the shape shown in FIG. 1 were stacked together, and the protective material was inserted inside with the uncoated side facing inward.
  • the protective material and the main panel were welded by the heat welding method 1.
  • the outer periphery was sewn with a sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 1 The evaluation results of the airbag using this film are shown in Table 1 below.
  • the main panel used was a PA base fabric that was not laminated.
  • the protective material used was a two-layered multilayer film with a layer structure of "adhesive layer/outer layer", with PA6/66 for the adhesive layer and PA6 for the outer layer, extruded from a multilayer circular die and a multilayer film with a thickness of 30 ⁇ m was obtained by an inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked together, and the protective material was inserted inside with the uncoated side facing inside.
  • the protective material and the main panel were welded by ultrasonic welding.
  • the outer periphery was sewn with sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 1 The evaluation results of the airbag using this film are shown in Table 1 below.
  • the main panel used was a non-laminated PA base fabric.
  • the base fabric was cut into the shape shown in Figure 1 and two sheets were stacked together with the coated side facing inward to form the bag-shaped inflatable portion (main panel) of the airbag. No protective material was inserted. The outer periphery was then sewn with sewing thread.
  • Table 1 The evaluation results of this airbag are shown in Table 1 below.
  • the main panel used was a non-laminated PA base fabric.
  • the base fabric was cut into the shape shown in Figure 1 to form the bag-shaped inflatable part (main panel) of the airbag.
  • Silicone adhesive was applied to the sewn part, and two pieces were stacked together with the coated side on the inside. No protective material was inserted. The outer periphery was then sewn with sewing thread.
  • Table 1 The evaluation results of this airbag are shown in Table 1 below.
  • the main panel used was a laminated PA base fabric.
  • the protective material used was a three-kind, three-layer multilayer film with a layer structure of "adhesive layer/middle/outer layer", in which PA6/12 was used for the adhesive layer, PO for the middle layer, and PA12 elastomer for the outer layer were used, and the film was extruded from a multilayer circular die to obtain a three-kind, three-layer film with a thickness of 40 ⁇ m by an inflation method.
  • As the bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the uncoated side facing inward, and a protective material was inserted between them.
  • the protective material and the main panel were welded by the heat welding method 2.
  • the outer periphery was sewn with a sewing thread by the method of producing the main (base fabric) panel described above.
  • Table 2 The evaluation results of the airbag using this film are shown in Table 2 below
  • the main panel used was a laminated PA base fabric.
  • a protective material was welded to the laminated surface.
  • the protective material used was a single-layer film with a layer structure, and was extruded from a multi-layer circular die using PA6/12, and a single-layer film with a thickness of 40 ⁇ m was obtained by an inflation method.
  • As a bag-shaped inflatable part (main panel) of the airbag two sheets of the base fabric cut into the shape shown in FIG. 1 were stacked with the uncoated side on the inside, and a protective material was inserted between them.
  • the protective material and the main panel were welded by the heat welding method 2.
  • the outer periphery was sewn with a sewing thread by the method of producing the main (base fabric) panel described above.
  • the evaluation results of the airbag using this film are shown in Table 2 below.
  • a laminated resin film was used as the half-folded non-breathable film-like protective material, and the difference in SP value between the resin constituting the first surface layer and the resin constituting the second surface layer was set to 2.0 [cal/ cm3 ) 1/2 ] or more, or the melting point difference was set to 50°C or more.
  • the second surface layer peeled off when the airbag was deployed, and there was no welding of the loops, so the airbag internal pressure retention was high, and compactness was also good because silicone adhesive was not used in the sewn parts.
  • Comparative Example 1 since a single layer film was used, the loops were welded together, and the internal pressure retention rate of the airbag was deteriorated. In Comparative Example 2, the difference in SP value was less than 2.0, so the loops were welded together, and the internal pressure retention rate of the airbag was deteriorated. In Comparative Example 3, the internal pressure retention rate of the airbag was deteriorated because the half-folded non-breathable film-like protective material was not used. In Comparative Example 4, a silicone adhesive was used instead of the half-folded non-breathable film-like protective material, resulting in poor compactness.
  • Comparative Example 5 Although a multilayer film was used, the difference in melting points was less than 50° C., so that the loops were welded together, and the airbag's internal pressure retention was deteriorated. In Comparative Example 6, since a single layer film was used, the loops were welded together, and the internal pressure retention rate of the airbag was deteriorated.
  • the airbag and manufacturing method of the present invention have at least one pair of base fabric panels having bonded to each of the inner surfaces of both ends of a half-folded, strip-shaped, non-breathable protective material in bonding areas of a predetermined width along the seam from near the seam toward the inside of the bag, the bonding areas having proximal and distal ends, resulting in an airbag with high internal pressure retention performance and excellent compactness, and a manufacturing method for the airbag with high productivity. Therefore, the airbag and the manufacturing method thereof according to the present invention can be suitably used for automobile airbags, in particular, CAB and pedestrian airbags which are particularly required to have high internal pressure retention performance.
  • Base fabric panel (panel fabric, main panel) 1' Base fabric panel (panel fabric, main panel) Reference Signs List 2: Sewn (stitched) portion 2': Isolated sewn (stitched) portion 3: Silicone adhesive 4: Non-breathable (film-like) protective material 4': Inner edge of non-breathable (film-like) protective material 4": Half-folded strip-shaped non-breathable (film-like) protective material 5: Adhesive area 5': Adhesive area 6: Proximal end of adhesive area 6': Proximal end of adhesive area 7: Distal end of adhesive area 7': Distal end of adhesive area 8: End (sealed) portion of non-breathable (film-like) protective material 8': End (sealed) portion of non-breathable (film-like) protective material 10: Bag-shaped airbag with outer edge sewn A-A: Cross section 11: Multilayer film 11a: Multilayer film (outer layer) 11b Multilayer film (adhesive layer) 12 Multi-layer

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Air Bags (AREA)
PCT/JP2023/042581 2022-11-29 2023-11-28 内圧保持性能を高めたエアバッグ及びその製法 Ceased WO2024117135A1 (ja)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6435553B1 (en) * 2000-03-20 2002-08-20 Breed Automotive Technology, Inc. Air bag and method of seam assembly for minimizing gas leakage
JP2003514144A (ja) * 1999-11-17 2003-04-15 ミリケン・アンド・カンパニー 剥離継目を有する膨張式織物
JP2007223373A (ja) * 2006-02-21 2007-09-06 Nippon Plast Co Ltd エアバッグ及びエアバッグの製造方法
WO2010122852A1 (ja) * 2009-04-23 2010-10-28 芦森工業株式会社 エアバッグ装置
JP2015515942A (ja) * 2012-05-03 2015-06-04 ティーケー ホールディングス インク．Ｔｋ Ｈｏｌｄｉｎｇｓ Ｉｎｃ． 軽量エアバッグクッションを有するエアバッグモジュール

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003514144A (ja) * 1999-11-17 2003-04-15 ミリケン・アンド・カンパニー 剥離継目を有する膨張式織物
US6435553B1 (en) * 2000-03-20 2002-08-20 Breed Automotive Technology, Inc. Air bag and method of seam assembly for minimizing gas leakage
JP2007223373A (ja) * 2006-02-21 2007-09-06 Nippon Plast Co Ltd エアバッグ及びエアバッグの製造方法
WO2010122852A1 (ja) * 2009-04-23 2010-10-28 芦森工業株式会社 エアバッグ装置
JP2015515942A (ja) * 2012-05-03 2015-06-04 ティーケー ホールディングス インク．Ｔｋ Ｈｏｌｄｉｎｇｓ Ｉｎｃ． 軽量エアバッグクッションを有するエアバッグモジュール

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