WO2024117134A1 - 内圧保持性能を高めたエアバッグ - Google Patents

内圧保持性能を高めたエアバッグ Download PDF

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Publication number
WO2024117134A1
WO2024117134A1 PCT/JP2023/042578 JP2023042578W WO2024117134A1 WO 2024117134 A1 WO2024117134 A1 WO 2024117134A1 JP 2023042578 W JP2023042578 W JP 2023042578W WO 2024117134 A1 WO2024117134 A1 WO 2024117134A1
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WIPO (PCT)
Prior art keywords
airbag
protective material
base fabric
folded
adhesive
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/042578
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English (en)
French (fr)
Japanese (ja)
Inventor
拓海 壁谷
祐介 佐藤
達夫 田中
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
Original Assignee
Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Publication date
Application filed by Asahi Kasei Corp, Asahi Chemical Industry Co Ltd filed Critical Asahi Kasei Corp
Priority to JP2024561513A priority Critical patent/JPWO2024117134A1/ja
Publication of WO2024117134A1 publication Critical patent/WO2024117134A1/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.
  • 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 need to 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 need to maintain internal pressure 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 at the location where there is no adhesive (location where internal pressure does not need to be maintained) is 2.2 mm, while the folded thickness at the location where there is adhesive and sewing is 5.2 mm (corresponding to Comparative Example 4 in the present specification), 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 at least one pair of base fabric panels sewn together at their outer periphery, in which an airtight structure is formed by bonding the outer surfaces of both ends of a half-folded, 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, the bonding region having a proximal end and a distal end, and which is maintained even when the airbag is deployed, thereby improving the internal pressure retention performance and providing an airbag that is also highly compact.
  • 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, strip-shaped non-breathable protective material are bonded to the inner surface of each of the pair of base fabric panels in bonding regions of a predetermined width along the seams from near the seams toward the inside of the bag, and when a tensile force is applied to the pair of base fabric panels during deployment of the airbag, the length between the distal ends along the folded, strip-shaped non-breathable protective material is greater than or equal to the length between the distal ends along the pair of base fabric panels.
  • the folded band-shaped non-breathable protective material is a single resin film folded in half.
  • the ratio w/b of 1/2 of the length between the distal ends along the pair of base fabric panels (inter-bonding distance b) to the predetermined width w of the bonded region satisfies the relationship 0.2 ⁇ w/b ⁇ 5.0.
  • the airbag of the present invention has both end outer surfaces of a folded, strip-shaped, non-breathable protective material adhered to the inner surface of each of at least a pair of base fabric panels in adhesive regions of a predetermined width along the seams, the adhesive regions 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 adhesive regions, resulting in an airbag with high internal pressure retention performance and excellent compactness. Therefore, the airbag according to the present invention can be suitably used for automobile airbags, in particular for CABs and pedestrian airbags, which 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 the 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.
  • This is an explanatory diagram of the relationship between the specified width of the adhesive region, the adhesive distance b (1/2 the length between the distal ends along the base fabric panel), the adhesive distance a (1/2 the length between the distal ends along the half-folded non-breathable film-like protective material), and the seam allowance s of the base fabric panel.
  • 1 is an explanatory diagram showing the relationship between the resin constituting the first surface layer and the resin constituting the second surface layer of a laminated resin film which is a non-breathable film-like protective material folded in half.
  • 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. 1 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.
  • Two pieces of resin film, coated fabric, or laminated base fabric cut into a desired shape are used, and the outer layers of one end (inner edge side) of a multilayer film (for example, in the case of a multilayer film, part of the second surface layer is peeled off and the first surface layers are laminated together) or the non-coated surfaces of the base fabrics are laminated together, and the length from the outer edge is a predetermined length, and the two are laminated together by welding or adhesive along the inner edge.
  • 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.
  • 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. 17 is an explanatory diagram of the sealing state according to the method 1 shown in FIG. 16 .
  • 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 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 both end outer surfaces of a folded, strip-shaped non-breathable protective material bonded to the inner surface of each of the pair of base fabric panels at bonding regions of a predetermined width along the seams from near the seams toward the inside of the bag, and when a tensile force is applied to the pair of base fabric panels during deployment of the airbag, the length between the distal ends along the folded, strip-shaped non-breathable protective material is greater than or equal to the length between the distal ends along the pair of base fabric panels.
  • 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 weaving density of the base fabric used in this embodiment is preferably 30 to 90 threads/inch for both warp and weft
  • 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. Within this range, a base fabric that is flexible and has excellent airtightness when used as a base fabric for an airbag can be obtained.
  • the airbag according to this embodiment can be one in which a pair of base fabric panels are sewn together at their outer periphery 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 half-folded non-breathable protective material, which is on the back side of the front base fabric panel and which will be described below.
  • an inner tube reference numeral 23
  • reference numeral 23 made into a cylindrical shape from base panels of the same material can be inserted into the opening, and when the airbag inflates and deploys, 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 folded, strip-shaped non-breathable protective material are bonded 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, the adhesive region having a proximal end and a distal end, and the length between the distal ends along the folded, strip-shaped non-breathable protective material is greater than or equal to the length between the distal ends along the pair of base fabric panels 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.
  • Fig. 3 illustrates the state of the semi-folded non-breathable protective material when the airbag is deployed.
  • the semi-folded non-breathable protective material presents a loop shape toward the inside of the airbag and forms an airtight structure in the bonded area with the base fabric panel, thereby exhibiting internal pressure retention.
  • the length between the distal ends along the folded non-breathable protective material is greater than or equal to the length between the distal ends along a pair of fabric panels when the airbag is deployed, thereby maintaining an airtight structure in the adhesive region.
  • the loop-shaped protective material has a sufficient length, so that 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 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 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.
  • each base fabric panel is grasped and pulled in a direction parallel to the base fabric panel, it is confirmed whether the seam is broken before the protective material. At this time, attention is paid to arranging the seam so that it is approximately perpendicular to the pulling direction.
  • 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 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 housed in an airbag, as shown in the upper part of Figures 4(a) and (b), i.e., a material in which a strip-shaped single-layer or multi-layer resin film or laminate base fabric is half-folded, but also to a material that is folded multiple times, such as into an accordion-like shape, or to a material in which two strip-shaped (including curved) single-layer or multi-layer resin films or laminate base fabrics are overlapped 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 band-shaped non-breathable 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, coated fabric, or laminated base fabric cut into a desired shape, and overlapping the outer layers of one end (inner edge side) of the multilayer film (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) or the non-coated surfaces of the base fabric, and welding them together along the inner edge so that the length from the outer edge is a predetermined length, for example, at 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 band shape, but for example, by bonding two pieces of protective material cut into the base fabric panel shape (horse
  • the protective material by continuously supplying a band-shaped resin film folded in half and heat welding it while applying tension as shown in Figs. 9 to 11, rather than by manufacturing it by the two-sheet lamination method.
  • the two-sheet lamination method requires cutting out the resin film along the sewing shape of the airbag, by using a band-shaped resin film folded in half, the utilization efficiency of the film can be maximized, and the productivity can be increased because there is no process of bonding the films together. That is, since the film is cut into strips, there is little loss when cutting out the film, and there is no process of bonding the films together, so the productivity is high.
  • an actual airbag since an actual airbag is deployed instantly from a folded state, a part of the airbag may be exposed to a very fast inflator gas flow velocity at the beginning of deployment, etc., but by using a single resin film, the adhesive space between the resin films is not required, and the adhesive space can be prevented from being exposed to the gas flow velocity and being destroyed. Furthermore, since there is no need to bond resin films together, there is little change in thickness or hardness of the loop-shaped resin film between the distal ends along the half-folded band-shaped resin film, and even if the airbag is exposed to a high gas flow rate when it is deployed, stress concentration occurs at the location where the thickness or hardness changes at the adhesive interface between the resin films, etc., and the loop structure is prevented from being destroyed.
  • the airbag can be made lighter and the storability of the airbag can be improved.
  • a resin film is used as the half-folded non-breathable protective material, by using a manufacturing method in which the resin film is continuously supplied and thermally welded while applying tension, as described below, even if the material is a single sheet of non-breathable protective material, it is possible to weld even curved portions (including R portions and reverse R portions) without wrinkles, and to produce an airbag with excellent airtightness.
  • the band-shaped non-breathable protective material folded in half is preferably "a single resin film folded in half," but in this specification, the term “a single resin film folded in half” means that the film is continuously manufactured as shown in Figures 13 and 14, folded in half to form a roll as shown in Figure 9, and integrated at the point where it can be unwound and supplied for bonding to the base fabric panel, making it a single piece, regardless of whether such a single piece is a multilayer resin film or whether it has been cut to a specified length.
  • the term "a single resin film folded in half” does not include those made by the two-sheet lamination method, as mentioned above.
  • non-breathable protective material there are no particular limitations on the non-breathable protective material as long as it is not destroyed when the airbag is inflated or deployed, and single-layer or multi-layer resin films, woven fabrics, knitted fabrics, nonwoven fabrics, etc. can be used.
  • a substrate such as woven fabric, knitted fabric, or nonwoven fabric
  • a single-layer or multi-layer resin film it is more preferable to use a single-layer or multi-layer resin film as the non-breathable protective material rather than a coated fabric or laminated base fabric.
  • the adhesive strength can be increased and the internal pressure retention of the airbag can be improved by bonding the substrate panel laminated with the same type of single-layer or multi-layer resin film. Furthermore, by using the same type of single-layer or multi-layer resin film (and substrate) used for the non-breathable protective material and the base fabric panel, recyclability can be improved.
  • 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 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 "bonding region (5, 5')" has a proximal end (6, 6') and a distal end (7, 7') with respect to the seam (2).
  • the proximal end (6, 6') may be located on the inside of the airbag from the seam (2) (see the upper part of Figures 4(a) and 4(b) and the lower part of Figure 5) or on the outside of the airbag (see the upper part of Figure 5). In the latter case, the bonding region will extend to the seam allowance s. Also, as shown in Fig.
  • 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 in the same manner as in the case of Fig. 4(a).
  • the "bonded region” need only be bonded in such a way that it will not be destroyed or peeled off when the airbag inflates and deploys, and that it maintains airtightness and internal pressure retention.
  • the distal end is the reference point for the bonded distance a from the seam to the distal end (1/2 the length between the distal ends along a pair of base fabric panels) and the bonded distance b (1/2 the length between the distal ends along the folded non-breathable protective material).
  • 1/2 of the length between the distal ends along the folded non-breathable protective material (adhesive distance a) and 1/2 of the length between the distal ends along the pair of base fabric panels (adhesive distance b) are preferably in the relationship of 0.5 ⁇ a/b ⁇ 10, more preferably 1.0 ⁇ a/b ⁇ 2.0, and even more preferably 1.1 ⁇ a/b ⁇ 1.8.
  • the adhesive region must not break and airtightness must be maintained, but the value of a/b can be appropriately adjusted taking into account the elasticity of the base fabric panel and the protective material.
  • the protective material has extensibility and stretchability.
  • half of the length between the distal ends along the folded non-breathable protective material is preferably 0.1 cm or more and 10.0 cm or less, and more preferably 0.5 cm or more and 4.0 cm or less, from the viewpoints of airtightness and folded thickness.
  • the predetermined width w of the adhesive region is preferably 0.1 cm or more and 5.0 cm or less, and more preferably 0.5 cm or more and 3.0 cm or less, from the viewpoints of airtightness and folded thickness.
  • the effective adhesive width which is the smaller of 1/2 the length between the distal ends along the pair of base fabric panels (adhesive distance b) and the specified width w of the adhesive region, is preferably 0.1 cm or more, and more preferably 0.5 cm or more, from the standpoint of airtightness and folded thickness.
  • the ratio w/b of 1/2 of the length between the distal ends along the pair of base fabric panels (bonding distance b) to the predetermined width w of the bonded area is preferably in the range of 0.2 ⁇ w/b ⁇ 5.0, and more preferably 0.5 ⁇ w/b ⁇ 2.0, from the standpoint of airtightness and folded thickness.
  • the thickness of the non-breathable protective material is preferably 0.001 mm or more and 0.5 mm or less, and more preferably 0.001 mm or more and 0.1 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 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 panel base fabric due to the wind pressure of the gas when the airbag is deployed is significantly reduced.
  • the airbag (cushion) of this embodiment may include an isolated sewn portion (in the center) of a closed space as shown in FIG. 15. A method for manufacturing an airbag having an isolated sewn portion of a closed space will be described later.
  • the tensile modulus of the half-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 fit the curved parts (including R parts and reverse R parts) that are usually used in the main fabric of an airbag.
  • 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 preferably 10 to 100 MPa or less, the rigidity is suppressed and the film has good handling properties.
  • a thermoplastic resin film since the film can be easily stretched by applying heat.
  • 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 15.
  • 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.
  • the method for manufacturing the airbag of the present embodiment is not particularly limited.
  • the method for manufacturing the airbag may include the following steps: 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 fabric panels to weld the first surface layer to the inner surface of the pair of fabric panels, wherein the second surface layers are not welded to each other by thermal welding or ultrasonic welding, or are welded to each other by thermal welding or ultrasonic welding, but the second surface layers peel off when a tensile force is applied to the pair of fabric panels when the airbag is
  • 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 that is folded in half, to be 50°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 value of the resin constituting the first surface layer and the resin constituting the second surface layer of the laminated resin film, which is a non-breathable film-like protective material that is folded in half, between adjacent layers to be 2.0 [cal/ cm3 ) 1/2 ] or more, so that delamination of the first surface layer occurs or the second surface layer peels off from the first surface 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
  • the melting point of TPEE is 216°C
  • the melting point of PA6/66 is 194°C
  • the melting point of PA12 elastomer is 176°C
  • the melting point of PO acid-modified polyethylene
  • the melting point of PE is 110°C.
  • the difference between the melting point of the resin constituting the first surface layer and the melting point of the resin 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 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 (first surface layer) or PE (second surface 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 can be 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 any of the adjacent layers constituting the first surface layer, the adhesive layer (PA6/12), the X layer (e.g., the intermediate layer (acid-modified PE)), and the high melting point layer (PA6/66), 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 can be achieved by making the HSP value difference 1.0 (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 a pair of base fabric panels are sewn together at their outer periphery to form a bag body, An airbag can be provided with high productivity 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 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 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, and 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.
  • the airbag of the present embodiment can also be manufactured (provided) with high productivity by using the manufacturing method described below.
  • a welding step of continuously sandwiching a semi-folded, band-shaped non-breathable film-like protective material, which is made of a single-layer resin film having a predetermined width and a release paper sandwiched therebetween or 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 straight or curved outer periphery of the pair of base fabric panels while applying tension thereto, and welding a surface of the single-layer resin film or the first surface layer to the inner surface of the base fabric panel by applying heat or ultrasonic waves from the outside of the pair of base fabric panels, wherein although the surfaces of the single-layer resin film on the release paper side
  • the tensile modulus of the film referred to here is a measurement result when the band-shaped non-permeable and breathable film-like protective material is opened from a half-folded state and pulled.
  • the band-shaped non-permeable and breathable film-like protective material is deformed to follow the curved outer periphery by applying tension
  • the above tensile modulus (flexibility) makes it easy to form a curved structure along 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 a good handleability (balance between ease of deformation at the curved part 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.
  • the tensile breaking strength is preferably 10 to 100 MPa or less, the rigidity is suppressed, resulting in a film with good handleability.
  • methods for sandwiching a strip-shaped non-air-permeable, 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 half-folded film in advance and sending the strip-shaped non-air-permeable film-like protective material from the roll to the welding point by heat welding or ultrasonic welding, as exemplified in Figures 9 to 11, a method of preparing a roll of the strip-shaped non-air-permeable film-like protective material in an unfolded state in advance and folding the strip-shaped non-air-permeable film-like protective material in half during the process of sending it from the 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-air-permeable 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
  • 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 peripheral edge of the airbag while holding the tape with one hand and the base fabric with the other hand, as shown in Fig. 11.
  • 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 applying 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 portion 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 first fed onto one base fabric panel while applying tension, and then the tape is welded onto the first base fabric by heating from below, thereby fixing the tape onto one base fabric panel without wrinkles (1st step). Then, a second base fabric is placed on top of the tape, and pressure-bonded by heating by 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. Also, since the tape is not sandwiched between the base fabrics, a situation in which the space becomes narrow at the final stage of bonding does not occur.
  • 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 as to follow the shape of the outer periphery of the airbag, while holding the tape with one hand and the base fabric with the other hand, can be used, similar to the above-mentioned tension application and sandwiching method.
  • a roll of a half-folded film may be prepared in advance, and a tension control mechanism may be provided in the process of feeding a strip-shaped non-breathable film-like protective material from the roll to a welding location by thermal welding or ultrasonic welding.
  • this manufacturing method like the above-mentioned tension application and clamping method, it is possible to preheat a part or the whole of the tape, provide a cooling section, and apply/release the pressure of the hot plate and the cold plate intermittently.
  • preheating the tape for example, while the tape is welded onto the first base fabric by the hot plate from below the belt thermocompression machine, the tape can be assisted in stretching the R and reverse R portions by heating with the upper hot plate.
  • the method for placing the second base fabric on the tape and heating by thermal welding or ultrasonic welding is not particularly limited, and may be continuously welded using a belt heat pressing machine as in the first step, or may be welded 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.
  • the first step is expected to have the secondary effect of improving the processing speed by temporarily fixing the welded parts.
  • the non-breathable protective material is "adhered to the overlapping manner" means that a plurality of the non-breathable protective materials are arranged in an overlapping manner, the non-breathable protective materials are adhered to each other, and the non-breathable protective material closest to the base fabric panel is adhered to the inner surface of each of the pair of base fabric panels.
  • the non-breathable protective materials may be overlapped at the same sewing portion and adhered to each other, or in a sewing shape having a branch point, a half-folded band-shaped non-breathable protective material arranged near one sewing line and a half-folded band-shaped non-breathable protective material arranged near the other sewing line may be partially overlapped and adhered near the sewing branch point.
  • the multiple non-breathable protective materials are united to form a loop-shaped structure bonded to the inner surface of each of the base fabric panels, and when a tensile force is applied between the pair of base fabric panels, a state can be formed in which the length between the distal ends along the folded non-breathable protective materials is greater than or equal to the length between the distal ends along the pair of base fabric panels.
  • the term "sealed end portions" of the non-breathable protective materials refers to a state in which the end portions of the plurality of non-breathable protective materials are not open to the inflatable portion (chamber) of the airbag.
  • the method for sealing the end portions of the non-breathable protective materials is not particularly limited, and may be adhesion with an adhesive, heat welding, ultrasonic welding, or folding the non-breathable protective materials. Also, as shown in FIG. 18, a structure in which the end portions are exposed to the outside of the inflatable portion (chamber) may be used.
  • This manufacturing method 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.
  • the tension application or clamping method it can be widely applied to the 2-step method, the two-sheet bonding method, etc.
  • Si-coated fabric used as the base fabric panel and/or protective material was a plain weave fabric woven using nylon 66 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 .
  • the multilayer film was laminated on one side of a plain weave fabric woven using nylon 66 multifilament fibers as the warp and weft.
  • the total fineness of the weaving yarn constituting the base fabric was 470 dtex, the number of filaments was 136, and the weaving density of the coated fabric was 49/inch (2.54 cm).
  • the multilayer film used was a three-kind, three-layer film with a layer structure of "adhesive layer/middle layer/outer layer".
  • PA6/12 was used 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 three-kind, three-layer film with a thickness of 20 ⁇ m.
  • the adhesive layer was used as the surface to be laminated to the plain weave base fabric.
  • the multilayer film and the nylon 66 base fabric were overlapped and bonded using a laminator (see FIG. 14) so that the multilayer film was in contact with the silicone rubber roll.
  • the lamination conditions were as follows: Temperature: 160°C Roll speed: 0.3 m/min Linear pressure: 2.3 kg/cm
  • the film used as the protective material was produced as follows. As shown in FIG. 13, a multi-layer circular die was used to wind the desired multi-layer 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 films used in Examples 1-3, 5, 7, 9-15, 17, 19-22 and Comparative Examples 2 and 5 were 4-type, 4-layer multilayer films with a thickness of 20 ⁇ m consisting of "adhesive layer/intermediate/resin layer 1/resin layer 2".
  • the adhesive layer was made of PA6/12
  • the intermediate layer was made of m-PE
  • the resin layer 1 was made of PA6/66
  • the resin layer 2 was made of PE (LDPE).
  • the films were extruded from a multilayer circular die and obtained by the inflation method.
  • the tensile modulus in the MD direction was 210 MPa, and the tensile modulus in the TD direction was 200 MPa.
  • the tensile elongation at break in the MD direction was 420%, and the tensile elongation at break in the TD direction was 350%.
  • the film (low modulus) used in Examples 8 and 18 was a 20 ⁇ m thick multilayer film of 5 types and 6 layers consisting of "adhesive layer/intermediate/resin layer 1/intermediate/resin layer 2/resin layer 3".
  • the adhesive layer was made of PA6/12
  • the intermediate layer was made of m-PE
  • the resin layer 1 was made of PO elastomer
  • the resin layer 2 was made of PA6/66
  • the resin layer 3 was made of PE (LDPE).
  • the film was extruded from a multilayer circular die and obtained by the inflation method.
  • the tensile modulus in the MD direction was 160 MPa, and the tensile modulus in the TD direction was 150 MPa.
  • the tensile elongation at break in the MD direction was 500%, and the tensile elongation at break in the TD direction was 440%.
  • 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.
  • ASTM-D-882 a sample cut from the film in the MD or TD direction was displaced from 0.05% to 0.25% under the conditions of a tensile speed of 5 mm/min (strain speed of 5%/min) and a chuck distance of 100 mm, and the tensile modulus was calculated from the stress when the sample was displaced from 0.05% to 0.25%.
  • the tensile modulus of the film is the measurement result when a band-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 tensile elongation at break of the film is the measurement result when a band-shaped non-permeable and breathable film-like protective material is opened from a half-folded state and pulled. 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 100%/min is selected.
  • Glass Transition Temperature (Tg) of Film A film prepared by the inflation method according to the above-mentioned "Film Preparation Method” was measured in accordance with JIS K 7121.
  • 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.
  • Adhesion strength peel strength between protective material and panel cloth (N/cm)
  • the airbag was cut into 100 ⁇ 10 strips perpendicular to the seam.
  • the protective material and the main panel extending from the proximal end of the adhesive region on one side were cut along the proximal end.
  • the main panels extending from the distal ends of the adhesive regions on both sides were cut along their distal ends, respectively.
  • test sample was prepared in which the (strip-shaped) main panel on one side and the (strip-shaped) protective material were bonded in the adhesive region on one side.
  • the main panel and protective material of the test sample were each held in the chuck (chuck width 25 mm) of a Tensilon universal material testing machine manufactured by A&D Co., Ltd., and pulled at an initial length of 100 mm and a pulling speed of 50 mm/min, and the maximum strength generated when the main panel and protective material were peeled off was recorded.
  • Three samples were prepared, and the average value of the three measurements was recorded as the adhesive strength (peel strength) between the protective material and the panel fabric.
  • the first break point was determined to be the protective material.
  • Three test samples were prepared, and the part where breakage was observed in a total of three measurements was determined to be the first break point of the panel part gripping tensile test. Although it is difficult to accurately measure the state of the airbag at the moment of deployment, this can be roughly substituted by observing the first breaking point in the panel grip tensile test.
  • 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 6 seconds, expressed as a percentage.
  • the straight stitched portion (part B in FIG. 1) of the main panel sewn according to each specification described below was cut to obtain a 60 mm x 30 mm sample piece for thickness evaluation.
  • the cut sample piece was folded in half perpendicular to the straight stitching to produce a folded sample of 30 mm x 30 mm.
  • a digital caliper ABS Digimatic Caliper CD-20APX
  • the measurement part of the caliper was used to pinch the stitched portion 10 mm from the fold and press it with a force of 300 gf, and the value was recorded.
  • the test was performed once for each of the three airbags, and the average value of the three measurements was taken as the thickness after folding.
  • a measurement sample of 2 cm x 2 cm was cut out so that the identified wrinkled portion or measurement point was approximately centered.
  • the measurement sample was placed on a glass plate with the protective material surface facing upward, and the four sides of the measurement sample were fixed with commercially available adhesive tape (product name: Cellotape/manufactured by Nichiban Co., Ltd.) so that the measurement sample did not generally float from the glass plate.
  • the measurement sample was set on the measurement table of a surface roughness measuring instrument (SURFTEST EXTREME SV-3000CNC) manufactured by Mitutoyo Corporation, and the specified wrinkled portion or measurement point was measured in three-dimensional mode according to the following measurement conditions.
  • the obtained three-dimensional measurement data was imported into image analysis software (FORMTRACEPAK PRO) to create a three-dimensional mapping image with "plane” correction processing added, and the largest step portion was extracted using an arbitrary cross-section extraction function, and a baseline connecting the start point and end point of the highest peak in the extracted cross-section (two dimensions) was drawn, and the maximum height from the baseline was determined.
  • FORMTRACEPAK PRO image analysis software
  • Adhesion strength peel strength
  • panel cloth N/cm
  • a test sample was prepared in which the (strip-shaped) main panel on one side and the (strip-shaped) protective material were bonded in the adhesive region on one side.
  • the radius of curvature of the sewn curved portion (R portion) of the obtained sample was 200 mm.
  • the main panel and protective material of the test sample were each held in the chuck (chuck width 25 mm) of a Tensilon universal material testing machine manufactured by A&D Co., Ltd., and pulled at an initial length of 100 mm and a pulling speed of 50 mm/min, and the maximum strength generated when the main panel and protective material were peeled off was recorded.
  • Three samples were prepared, and the average value of the three measurements was recorded as the adhesive strength (peel strength) between the protective material and the panel fabric in the R section.
  • Comparative Example 1 a silicon-coated fabric was used as the protective material, and the loop was formed on the inside of the airbag by sandwiching it between the stitches of the panel fabric, and no adhesive was used between the protective material and the panel fabric. Because there was no adhesive area, the internal pressure retention rate after 6 seconds was low.
  • Comparative Example 2 an airbag was produced in the same manner as in Comparative Example 1, except that the protective material was replaced with a film. As in Comparative Example 1, there was no adhesive area, so the internal pressure retention rate after 6 seconds was low.
  • Comparative Example 3 no protective material was used, and laminated fabric was used as the main panel. The laminated surfaces were bonded together by heat welding, and the main panels were not sewn together. Because there was no sewing, the airbag was unable to withstand the deployment pressure when it was deployed and was destroyed, and the internal pressure retention rate after 6 seconds was also low. Because there was no sewing, the first breaking point in the panel grip tensile test was the adhesive part.
  • Comparative Example 4 a Si-coated cloth was used as the panel cloth, and a silicone-based adhesive was applied to the sewing points with the Si-coated side facing inward so that the width was approximately 10 mm and the thickness was approximately 2 mm. Another piece of panel cloth was then attached from above with the Si-coated side facing inward, and allowed to dry thoroughly. At this time, the amount of silicone-based adhesive applied per 1 cm of the length of the sewn part of the airbag was 0.15 to 0.25 g. After drying, the part attached with the silicone-based adhesive was sewn. The obtained airbag was thick after folding, the weight of the standard bag was also large, and the manufacturing time per bag was long.
  • Comparative Example 5 a film was used as the protective material, and two panels of cloth were sandwiched together with their Si-coated surfaces facing outward so that a loop was formed on the inside of the airbag. The protective material and the panel cloth were then heat-sealed and then sewn together. Because the protective material had been cut in advance to the shape shown in Figure 12, the heat-sealing was performed without applying tension. Because the adhesive distance a of the protective material was shorter than the adhesive distance b of the panels, the heat-sealed portion was partially destroyed when the airbag was deployed, and the internal pressure retention rate after 6 seconds was also low.
  • Example 1 a Si-coated cloth was used as the panel cloth with the Si-coated side facing outward, a film was used as the protective material, and the two panels of cloth were sandwiched together so that a loop was formed on the inside of the airbag.
  • the protective material and the uncoated side of the panel cloth were then bonded by heat welding, and the panel cloths were then sewn together. Because the protective material had been cut in advance to the shape shown in Figure 12, the heat welding was performed without applying tension. The resulting airbag had good physical properties and effects.
  • Example 2 as shown in FIG. 4(b), an airbag was produced in the same manner as in Example 1, except that the loops of protective material were formed on the outside of the airbag.
  • the production time per bag was slightly longer.
  • Example 3 a Si-coated cloth was used as the panel cloth with the Si-coated surface facing inward, a film was used as the protective material, and the two panels were sandwiched together so that a loop was formed on the inside of the airbag.
  • the protective material and the Si-coated surface of the panel cloth were then bonded together with a silicone adhesive, and the panel cloths were then sewn together. Because the protective material had been cut in advance to the shape shown in Figure 12, the heat welding was performed without applying tension.
  • the resulting airbag was inferior in terms of thickness after folding, weight of the reference bag, and manufacturing time per bag.
  • Example 5 a laminated cloth was used as the panel cloth with the laminated surface facing inward, a film was used as the protective material, and the two panels of cloth were sandwiched together so that a loop was formed on the inside of the airbag.
  • the protective material and the laminated surface of the panel cloth were then heat-sealed, and the panel cloths were then sewn together.
  • the protective material was previously cut into the shape shown in Figure 12, so the adhesion was performed without applying tension.
  • the resulting airbag had good physical properties and effects.
  • Example 6 an airbag was produced in the same manner as in Example 5, except that a laminated fabric was used as the protective material.
  • the resulting airbag was inferior in terms of thickness after folding and weight compared to the reference bag.
  • Example 7 an airbag was produced in the same manner as in Example 1, except that the protective material and the Si-coated surface of the panel cloth were bonded by thermal welding. The resulting airbag had a reduced internal pressure retention rate after 6 seconds due to a decrease in the adhesive strength between the protective material and the panel cloth.
  • Example 8 an airbag was produced in the same manner as in Example 1, except that a thicker film (low modulus of elasticity) was used as the protective material and the a/b ratio was lowered.
  • the resulting airbag had a worsened thickness after folding and a lower internal pressure retention rate after 6 seconds.
  • Example 9 an airbag was produced in the same manner as in Example 1, except that the a/b ratio was lowered. The resulting airbag had a lower internal pressure retention rate after 6 seconds.
  • Example 10 an airbag was produced in the same manner as in Example 1, except that the a/b ratio was increased. The resulting airbag had a worsened thickness after folding.
  • Example 11 an airbag was produced in the same manner as in Example 1, except that the effective bonding width (the smaller of b or W) was increased. The resulting airbag had a worsened thickness after folding.
  • Example 12 an airbag was produced in the same manner as in Example 1, except that the effective bonding width (the smaller of b or W) was reduced. The internal pressure retention rate of the resulting airbag after 6 seconds was reduced.
  • the effective bonding width the smaller of b or W
  • Example 13 a Si-coated cloth was used as the panel cloth with the Si-coated surface facing outward, a film was used as the protective material, and the two panels were sandwiched together so that a loop was formed on the inside of the airbag.
  • the protective material and the uncoated surface of the panel cloth were then bonded by heat welding, and the panel cloths were then sewn together.
  • the protective material was continuously fed from a wound roll and was attached while applying tension by hand so that it would conform to the shape shown in Figure 12.
  • the obtained airbag had good physical properties and effects, and had an excellent internal pressure retention rate (high output) after 6 seconds.
  • Example 14 an airbag was produced in the same manner as in Example 13, except that the protective material loops were formed on the outside of the airbag. The production time per bag was slightly longer.
  • Example 15 a laminated cloth was used as the panel cloth with the laminated surface facing inward, a film was used as the protective material, and the two panels were sandwiched together so that a loop was formed on the inside of the airbag.
  • the protective material and the laminated surface of the panel cloth were heat-sealed, and the panel cloths were then sewn together.
  • the protective material was continuously fed from a wound roll and attached while applying tension by hand so that it would conform to the shape shown in Figure 12.
  • the obtained airbag had good physical properties and effects, and had an excellent internal pressure retention rate (high output) after 6 seconds.
  • Example 16 an airbag was produced in the same manner as in Example 15, except that a laminated fabric was used as the protective material.
  • the resulting airbag was inferior in thickness after folding and weight to the reference bag.
  • Example 17 an airbag was produced in the same manner as in Example 13, except that the protective material and the Si-coated surface of the panel cloth were bonded by thermal welding.
  • the resulting airbag had a reduced internal pressure retention rate after 6 seconds due to a decrease in the adhesive strength between the protective material and the panel cloth.
  • Example 18 an airbag was produced in the same manner as in Example 13, except that a thicker film (low modulus of elasticity) was used as the protective material and the a/b ratio was lowered.
  • the resulting airbag had a worsened thickness after folding and a lower internal pressure retention rate after 6 seconds.
  • Example 19 an airbag was produced in the same manner as in Example 13, except that the a/b ratio was lowered. The internal pressure retention rate of the resulting airbag after 6 seconds was reduced.
  • Example 20 an airbag was produced in the same manner as in Example 13, except that the a/b ratio was increased. The resulting airbag had a worsened thickness after folding.
  • Example 21 an airbag was produced in the same manner as in Example 13, except that the effective bonding width (the smaller of b or W) was increased. The resulting airbag had a worsened thickness after folding.
  • Example 22 an airbag was produced in the same manner as in Example 13, except that the effective bonding width (the smaller of b or W) was reduced. The internal pressure retention rate of the resulting airbag after 6 seconds was reduced.
  • Example 23 a Si-coated cloth was used as the panel cloth with the Si-coated surface facing inward, and a Si-coated cloth was used as the protective material.
  • the two panels were sandwiched together so that a loop was formed on the inside of the airbag, and the panel cloths were then sewn together.
  • the protective material and the Si-coated surface of the panel cloth were then bonded together on the inside of the stitching with a silicone adhesive.
  • the protective material was fixed in place by the stitching, so the bonding was performed without applying tension to the protective material.
  • Example 24 a laminated fabric was used as the panel fabric with the laminated surface facing inward, a film was used as the protective material, and the two panels were sandwiched together so that a loop was formed on the inside of the airbag.
  • the panel fabrics were then sewn together, and the protective material and the laminated surface of the panel fabric were heat welded on the inside of the stitching.
  • the protective material was fixed in place by the stitching, so the bonding was performed without applying tension to the protective material.
  • the airbag according to the present invention has both outer surfaces of a folded, band-like, non-breathable protective material bonded to the inner surface of each of a pair of base fabric panels in a bonding region of a predetermined width along the seam, with a proximal end and a distal end from near the seam toward the inside of the bag, resulting in an airbag with high internal pressure retention and excellent compactness. Therefore, the airbag according to the present invention can be suitably used for automobile airbags, particularly CAB and pedestrian airbags, which require high internal pressure retention.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Air Bags (AREA)
PCT/JP2023/042578 2022-11-29 2023-11-28 内圧保持性能を高めたエアバッグ Ceased WO2024117134A1 (ja)

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05301554A (ja) * 1992-04-27 1993-11-16 Toyo Tire & Rubber Co Ltd エアバッグ装置
JP2001518860A (ja) * 1997-03-26 2001-10-16 ティーアールダブリュー・オキュパント・リストレイント・システムズ・ゲーエムベーハー・ウント・コンパニー・カーゲー 側方衝撃保護装置
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
JP2020075573A (ja) * 2018-11-06 2020-05-21 トヨタ自動車株式会社 車両用カーテンエアバッグ装置
WO2021157725A1 (ja) * 2020-02-07 2021-08-12 旭化成株式会社 エアバッグ用基布及びそれを含むエアバッグ

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05301554A (ja) * 1992-04-27 1993-11-16 Toyo Tire & Rubber Co Ltd エアバッグ装置
JP2001518860A (ja) * 1997-03-26 2001-10-16 ティーアールダブリュー・オキュパント・リストレイント・システムズ・ゲーエムベーハー・ウント・コンパニー・カーゲー 側方衝撃保護装置
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
JP2020075573A (ja) * 2018-11-06 2020-05-21 トヨタ自動車株式会社 車両用カーテンエアバッグ装置
WO2021157725A1 (ja) * 2020-02-07 2021-08-12 旭化成株式会社 エアバッグ用基布及びそれを含むエアバッグ

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