WO2005023601A1 - Material for a part of a protective bag - Google Patents

Material for a part of a protective bag Download PDF

Info

Publication number
WO2005023601A1
WO2005023601A1 PCT/GB2004/003776 GB2004003776W WO2005023601A1 WO 2005023601 A1 WO2005023601 A1 WO 2005023601A1 GB 2004003776 W GB2004003776 W GB 2004003776W WO 2005023601 A1 WO2005023601 A1 WO 2005023601A1
Authority
WO
WIPO (PCT)
Prior art keywords
adhesive
material according
patch
air bag
bag
Prior art date
Application number
PCT/GB2004/003776
Other languages
French (fr)
Inventor
Christopher Peter Willcock
Original Assignee
Atc Manufacturing Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Atc Manufacturing Limited filed Critical Atc Manufacturing Limited
Publication of WO2005023601A1 publication Critical patent/WO2005023601A1/en

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Classifications

    • 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
    • B60R21/235—Inflatable members characterised by their material
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/21—Paper; Textile fabrics
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/35—Heat-activated
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2483/00—Presence of polysiloxane

Definitions

  • the present invention relates to a material for a part (and especially for patches) of a protective bag for use within a vehicle, patches for applying to articles, a method of producing a material for a part (and especially for patches) of a protective bag for use within a vehicle, a method of forming a material for a part (and especially a patch) of a protective bag for use within a vehicle, a material for a vehicle air bag application and a conduit for use in a vehicle air bag.
  • Air bags for vehicles comprise patches in order to reinforce the bags in particular areas or to provide a heat shield to protect and reinforce the bag at specific locations.
  • patches are secured to the material of the air bag by initially applying a wet adhesive to the air bag, for example by using a screen printing method.
  • the patch is then placed on to a machine to apply pressure and heat to the patch to provide a secure attachment of the patch and the air bag. Accordingly, applying the patches can be messy and is time consuming.
  • Air bags include gas generators which distribute gases into a distribution system within the air bag. Such systems generally comprise substantially rigid lances which can be expensive and/or require a considerable volume especially whilst the air bag is in a packed configuration. It is understood that the air bag may be filled with any suitable gas mixture and the term air bag relates to any gas filled protective bag for a vehicle.
  • a material for a part of a protective bag for use within a vehicle comprising a support material and an adhesive, wherein the adhesive is actuated by actuating means.
  • the part of the protective bag is arranged, in use, to be secured to a second part of the protective bag by the adhesive, once actuated.
  • the protective bag comprises a vehicle air bag.
  • the material may form a patch for a vehicle air bag.
  • the patch may form a strip for a part of vehicle air bag and may form a part of a conduit.
  • the adhesive comprises a cross-linkable system.
  • the adhesive comprise a one part system.
  • the adhesive may comprise a two part system.
  • the actuating means comprises heat.
  • the adhesive is actuated at a temperature greater than room temperature.
  • the adhesive is actuated at a temperature greater than 40 °C and more preferably greater than 50 °C.
  • the actuating means causes the adhesive to cure .
  • the material or patch is arranged, in use, to be secured to an inflatable article.
  • the material or patch is arranged, in use, to be secured to a vehicle air bag.
  • the material may form at least a part of a vehicle air bag.
  • the support material comprises a textile.
  • the support material comprises a synthetic material.
  • the support material comprises a woven material.
  • the support material comprises a synthetic polymer.
  • the synthetic polymer is capable of being drawn into filaments which may be used to produce a yarn which may be capable of being woven and preferably to form a fabric.
  • the support material may be woven with greater than 5 yarns per cm and preferably greater than 10 yarns per cm and more preferably greater than 12 yarns per cm.
  • the support material may be woven with less than 50 yarns per cm and preferably less than 40 yarns per cm and more preferably less than 30 yarns per cm.
  • the support material may be coated with a coating material.
  • the coating material may comprise silicone and preferably comprises a liquid silicone rubber.
  • the coating material may comprise an addition curing system.
  • the addition curing system may be catalysed by a platinum complex.
  • the coating may be applied to the support material using a knife coating method.
  • the weight of the coating may be greater than 5 g/m 2 and preferably is greater than 8 g/m 2 and more preferably is greater than 10 g/m 2 .
  • the support material comprises a polyamide.
  • the support material comprises polyamide 6.6.
  • the adhesive comprises a dry adhesive.
  • the adhesive comprises a silicone adhesive.
  • the adhesive comprises an addition cure silicone adhesive.
  • the adhesive comprises a silicone rubber.
  • the adhesive may initially comprise a high viscosity paste.
  • the adhesive may be dissolved into a solvent for application to the support material.
  • the adhesive may be extruded for application to the support material.
  • the solvent may comprise a hydrocarbon solvent.
  • the solvent may comprise an alkane hydrocarbon.
  • the solvent may comprise heptane.
  • the solvent may comprise hexane.
  • the solvent may comprise may comprise a C 5 - C ⁇ alkane hydrocarbon.
  • the solvent may comprise a C 6 - C alkane hydrocarbon.
  • the solvent may comprise toluene.
  • the solid content of the silicone in the solvent may be greater than 20% and preferably is greater than 30%.
  • the solid content of the silicone in the solvent may be greater than 40% and preferably is greater than 50%.
  • the solid content of the silicone in the solvent may be substantially in the region of 40% to 50%.
  • the solid content of the silicone in the solvent may be less than 80% and preferably is less than 70%.
  • the weight of the adhesive in the material may be greater than 10 g/m and preferably is greater than 20 g/m 2 and more preferably is greater than 30 g/m 2 .
  • the material or patch is arranged to be secured to an article whilst under pressure.
  • the material or patch is arranged to be secured to an article in a hot press.
  • the material may comprise a sealing material.
  • the sealing material prevents or inhibits the adhesive being absorbed by the support material.
  • the sealing material is applied to the support material before the adhesive is applied.
  • the sealing material may comprise silicone and preferably comprises a liquid silicone rubber.
  • the sealing material may comprise greater than 95% silicone and preferably greater than 99% silicone and more preferably comprises 100% silicone.
  • the sealing material is only applied to one side of the material and preferably to the side of the material on which the adhesive surface will eventually locate.
  • the sealing material may be applied by a knife coating method.
  • the weight of the sealing material may be greater than 5 g/m 2 and preferably is greater than 15 g/m 2 and more preferably is greater than 20 g/m 2 .
  • the weight of the sealing material may be less than 70 g/m 2 and preferably is less than 50 g/m 2 and more preferably is less than 40 g/m 2
  • the sealing material comprise an addition curing system.
  • the addition curing system may be catalysed by a platinum complex.
  • the material may comprise a protective carrier layer.
  • the protective carrier layer is removable from the material to expose the adhesive surface.
  • the protective carrier layer may comprise a flexible substrate.
  • the protective carrier layer may comprise paper.
  • the protective carrier layer may comprise a polymer film.
  • the protective carrier layer may comprise a polyethylene film and preferably comprise a low density polyethylene film.
  • the - protective carrier layer has low surface energy.
  • the material may be rolled up and may be rolled on to carrier means, for example on to a tube.
  • the article may comprise an air bag for a vehicle.
  • the patch may comprise a protective patch for an air bag for a vehicle.
  • the protective patch may comprise a reinforcement patch and/or a thermal shield patch.
  • the material may form a conduit for fluid flow and preferably forms a part of a tube for gas distribution within a vehicle air bag.
  • the conduit may have apertures defined therein.
  • the article may comprise a balloon and may comprise a hot air balloon.
  • the adhesive may be reactivatable.
  • a patch for applying to an article comprising a material in accordance with the first aspect of the present invention.
  • the patch may comprise a strip of the material.
  • the patch may form part of a conduit.
  • the patch may form part of a gas distribution conduit which preferably is used within a vehicle protective bag.
  • the adhesive comprises a cross-linkable system.
  • the adhesive comprise a one part system.
  • the adhesive may comprise a two part system.
  • the patch is preferably a self adhesive patch.
  • the patch is a patch for a vehicle air bag.
  • the patch may be a protective patch.
  • the patch may be a reinforcement patch and/or a heat shield patch.
  • a method of producing a material for a part of a protective bag for use within a vehicle comprising locating an adhesive on a support material wherein the adhesive is actuated by actuating means.
  • the method may comprise a method of producing a material for a patch.
  • the adhesive comprises a cross-linkable system.
  • the adhesive comprise a one part system.
  • the adhesive may comprise a two part system.
  • the method may comprise applying a coating to the support material.
  • the method may comprise applying a coating to both sides of the support material.
  • the material may comprise applying a sealing material on the material.
  • the method may comprise applying a sealing material on one side of the material and preferably on the side to which an adhesive surface will be subsequently located.
  • the method may comprise applying the adhesive on the sealing material.
  • the method may comprise applying a protective layer on the material and preferably locating a protective layer over the exposed adhesive surface of the material.
  • the method may comprise rolling up the material.
  • the method may comprise cutting the material into patches.
  • a method of forming a part of a protective bag for use within a vehicle comprising cutting a material wherein the material is in accordance with the first aspect of the present invention.
  • the method may comprise cutting a patch from the material.
  • the method may comprise adhering the material to a part of a vehicle air bag.
  • the adhesive comprises a cross-linkable system.
  • the adhesive comprise a one part system.
  • the adhesive may comprise a two part system.
  • a material for a patch to be secured to an article comprising a support material and an adhesive, wherein the adhesive is actuated by actuating means .
  • the patch may comprise a strip of material.
  • the article may comprise a vehicle air bag.
  • Figure 1 is schematic cross section of a preferred embodiment of the present invention.
  • Figure 2 is a front view of a vehicle air bag with preferred embodiments of patches of the present invention.
  • Figure 3 is a front view of a vehicle air bag prior to assembly with preferred embodiments of patches of the present invention.
  • Figure 4 is a front view of another embodiment of a vehicle air bag with preferred embodiments of patches of the present invention.
  • Figure 5 is a rear view of another embodiment of a vehicle air bag with preferred embodiments of patches of the present invention.
  • Figure 6 is a plan view of a further embodiment of a first part of a vehicle air bag.
  • Figure 7 is a schematic cross-section of a further embodiment of a first part of a vehicle air bag.
  • Figure 8 is a plan view of a further embodiment of a second part of a vehicle air bag.
  • Figure 9 is a schematic cross-section of a further embodiment of a second part of a vehicle air bag.
  • Figure 10 is a perspective view of a further embodiment of a part of a vehicle air bag.
  • Figure 11 is a perspective view of a further embodiment.
  • the present invention provides a material 10 for producing patches or other parts which comprise an adhesive 14 provided on a support material 14, as shown in Figure 1.
  • the material 10 can be produced in bulk in roll form, and cut to any desired shape by the end-user or intermediate processor, and then applied using hot press equipment to the end product or article, in particular to a vehicle air bag.
  • the support material 12 comprises a textile.
  • the textile comprises a web of a polyamide and preferably polyamide 6.6.
  • the support material 12 has a sealing layer 18 provided on at least one surface thereof.
  • the sealing layer 18 prevents or inhibits the adhesive 14 being absorbed by the textile layer 12.
  • the sealing layer 18 comprises silicone and preferably 100% silicone.
  • the textile 12 preferably is coated with a coating 16 material on both sides thereof and is coated by immersing the textile 12 in liquid silicone. The coating strengthens the textile and also prevents or inhibits fluids (for example gases) from passing through the material .
  • the material 10 has an adhesive 14 applied to one surface thereof.
  • the material 10 has an adhesive layer 14 on one surface thereof.
  • the adhesive comprises a silicone adhesive and specifically a silicone adhesive with a one part system and is only actuated (or activated) to cure by actuating means (or activating means) , for example, heat. The adhesive does not cure until heated to a temperature greater than 50 °C.
  • the adhesive layer 14 is tacky at room temperature but would not form a secure bond until heated. Accordingly, the material 10 is provided with a protective layer 20 comprising a film which protects the adhesive layer, for example from grease, dirt, contaminants etc.
  • the film comprises a low density polyethylene.
  • the material 10 comprises a self adhesive material in which the adhesive will not cure until heated.
  • the material in order to provide a secure adhesive between the material and the article to which it is to be secured to, the material is simultaneously heated whilst pressure is applied between the material and the article.
  • the use of heat and pressure ensures a secure bond is formed between the material 10 and the article.
  • the heat and pressure is provided by a standard heat press as used in prior art vehicle air bag applications using wet adhesives.
  • the present invention is suitable for creating self adhesive patches 24, 26, 32 for vehicle air bags 22, 30 as shown in Figure 2 to 5.
  • the patches 24, 26, 32 may be reinforcing patches 24, 32 to strengthen the air bag 22, 30 at particular locations, for example in or around apertures 25, 33 and in particular adjacent to the entry aperture 25 or generator aperture and adjacent to vent apertures 32.
  • These patches 24, 32 prevent and inhibit the material of the air bag 22, 30 tearing as a result of the explosive force which the air bag 22, 30 is subjected to during inflation.
  • the reinforcing patches 24, 32 also protect the air bag material from the temperature of the gas (for example nitrogen) during the explosive inflation of the air bag 22, 30.
  • the patches 24, 26, 32 may either provide protection against tearing or protection against heat or protection against both tearing and heat.
  • the heat protection patches may be placed at locations in the air bag that will be the subject to the greatest temperature .
  • the material 10 is provided on a roll with the adhesive surface 14 (or protective layer 20) being on the inner surface.
  • the protective film 20 prevents the material 10 from sticking to itself. Manufacturers can then use their own standard cutting machines and apparatus to cut the patches 24, 26, 32 to the individual shapes required. Accordingly, the manufacturers do not have to produce patches of a particular shape or produce any new cutting apparatus or machines.
  • the patches 24, 26, 32 are placed on the surface of the air bag.
  • the air bag is turned inside out or are secured prior to stitching the air bag (as shown in Figure 3) such that the patches will eventually be on the internal surface.
  • the patches may be on the external surface of the air bag.
  • Figure 2 and Figure 3 illustrate an air bag 22 and in particular a thorax bag in which the edges of the template are stitched to form a seam 27 to complete the air bag
  • Figure 4 form the vehicle occupants side
  • Figure 5 illustrate a one piece woven air bag 30 which is turned inside out in order for the patch to locate inside the air bag 30.
  • the tacky surface of the adhesive 14 enables the patch 24, 26, 32 to be lightly adhered to the surface such that once the patch is in the correct location, the patch will not easily be accidentally moved out of alignment. Accordingly, the patch 24, 26, 32 does not require the use of a wet adhesive which is normally required and thereby does not require this normal step and/or the screen printing process and apparatus.
  • the air bag is located in a hot press which applies both pressure and heat to the patch. This causes the adhesive to cure and for the patch to be securely attached to the air bag 22, 30.
  • the patch could be used in other situations other than vehicle air bags 22, 30.
  • patches may be used to create decorative patterns or to display other information on hot air balloons and advertising balloons.
  • the adhesive 14 is integral with the support material 12 and, therefore, only a single bond is formed between the support material 12 and the material of the article.
  • Wet adhesive and other non-impregnated adhesives effectively form two bonds, one between the adhesive and the material of the article and one between the adhesive and the support material. Accordingly, such securement has an increased risk of failure due to double the number of bonds and also due to the adhesive possibly forming a firm band with one material to the detriment of the other.
  • the adhesive is usually comprised of a liquid silicone rubber (LSR), which is either addition or peroxide curing.
  • LSR liquid silicone rubber
  • the LSR cures quickly to form good adhesion between the patch and the bag.
  • pressure is used to bond the patch but a few days standing time may be required before full adhesion strength is attained.
  • the present invention does away with the necessity for the adhesive application and metering stages.
  • the patches are cut out as standard and are applied immediately prior to the pressing stage. Heat and pressure are used to bond the patches to the air bag and with full adhesion strength obtained immediately on cooling.
  • the patch comprises a woven synthetic material coated on both sides with silicone rubber.
  • the patches may comprise natural woven fabric materials and in one embodiment may comprise a material incorporating nanotechnology .
  • the support material is polyamide 6.6 but may be any synthetic polymer capable of being drawn into yarn and woven into fabric.
  • the yarn type can be of, but not limited to, 235-, 350-, 470-, 580- or 700-dtex (as these tend to be the standard yarn types offered for airbag applications) , with typical fabric setts ranging from, but not limited to, 12 yarns per cm to 30 yarns per cm.
  • the support layer should be capable of withstanding the elevated temperatures found during the deployment of an airbag (but this is dependent on the end use for the patch) .
  • the patch may be made up in a three- stage process, which comprises : (a) Application of a silicone coating to the face(s) or surface (s) of the support material. This provides protection to the patch support material. However in some cases, this face coating may be omitted dependent on the use and position of the patch within the air bag. Also, if the patch is intended for a non-airbag application e.g. balloon patch, then this face coating may be unnecessary.
  • the silicone coating can be applied using spreading techniques such as knife coating, but the end technique is very dependent on the mass of coating required and the coater's equipment. Any suitable coating equipment may be used. Typical weights for the protective face coating can range from 10g/m 2 upwards .
  • the silicone coating on the face usually comprises a liquid silicone rubber that uses addition-curing systems primarily of the type catalysed by platinum complexes.
  • Typical examples could be the systems offered by Wacker-Chemie GmbH, Dow Corning Corporation or Rhodia Silicones, examples of which could be Elastosil LR6251F (Wacker) , DC3625 (Dow Corning) and Rhodorsil TCS7534 (Rhodia) .
  • the adhesive may penetrate into the interstices of the weave which has the effect of leaving less adhesive available for chemical and mechanical adhesion to the surface being bonded to. This pre-coating of the fabric prevents this penetration and tests have found that adhesion is much improved when a base coat is used.
  • silicone coating can be applied using spreading techniques such as knife coating, but the end technique is very dependent on the mass of coating required and the coater's equipment. Any suitable coating equipment may be used. In order to get effective sealing of the surface, typical weights for the base coating can range from 20-
  • the silicone base coating usually comprises of an LSR (Liquid Silicone Rubber) that uses addition-curing systems primarily of the type catalysed by platinum complexes.
  • LSR Liquid Silicone Rubber
  • Typical examples could be the systems offered by Wacker-Chemie GmbH, Dow Corning Corporation or Rhodia Silicones, examples of which could be Elastosil LR6251F (Wacker) , DC3625 (Dow Corning) and Rhodorsil TCS7534 (Rhodia) .
  • (c) Application of the adhesive coating onto the base coating The silicone coating can be applied using spreading techniques such as knife coating, but the end technique is very dependent on the mass of coating required and the coater's equipment. Any suitable coating equipment may be used.
  • Typical weights for the adhesive coating can range from 30g/m 2 upwards, but this is very dependent on the weave and construction of both the support material of the patch and the material being bonded to. For example, a patch constructed of a 700-dtex support material of 15 x 15 yarns/cm being bonded to a fabric of similar type would require significantly more adhesive than a patch constructed of a 235-dtex material of 28 yarns/cm as the 235-dtex material is much flatter.
  • the silicone that has been used for the adhesive layer is an addition curing system that has been specially modified to be a one-pack system rather than the standard two-pack systems.
  • the curing system has been inhibited so that the cross- linking mechanism only occurs when the temperature of the system is raised for example by actuating means.
  • This system is Elastosil R Plus 4001/40MH produced by Wacker, dispersed in a suitable hydrocarbon solvent.
  • a dispersion of this rubber in solvent is commercially available as SLM45578 or SLM45579 (also from Wacker) .
  • This layer can be any flexible substrate e.g. paper, polymer film, which is either treated (or has existing inherent properties that allow it) to provide a surface of surface energy low enough to provide a clean release of the adhesive layer from it when the user requires.
  • the preferred material is a low-density polyethylene film seems to provide such properties at a relatively low cost.
  • the protective carrier layer must be introduced before the material is reeled up into a roll form.
  • FIG. 1 A cross sectional view of a preferred embodiment of the invention is shown in Figure 1.
  • Both the face coat silicone (coating material) and the base coat (sealing material) on the adhesive layer side are, as previously discussed, standard addition cure liquid silicone rubbers of the type used currently to produce coated materials for airbag applications. These are provided by the likes of Dow Corning, Wacker-Chemie, Rhodia and GE-Bayer Silicones. These are two-part systems in which the cross-linking agent (H-siloxane) is contained in one component, and the catalyst (the platinum complex) is contained in the other. Both components are stable until mixed, at which point cross-linking occurs. The cross-linking reaction is accelerated by the addition of energy (usually in the form of heat) , which is why these systems are usually cured at elevated temperatures. The catalyst is usually inhibited to some degree to prevent fast cure at lower temperatures (hence extending the pot life) but even so, the reaction will proceed slowly at room temperature and mixed systems will cure albeit over days rather than minutes or seconds.
  • the adhesive used in the present invention is a one-part system, with all the necessary components required for curing contained in this one part. However the system is inhibited so the catalyst will not become effective until a certain temperature is reached. This renders the silicone rubber stable until required, enabling it to be coated onto substrates without setting off the curing reaction. However, the temperature during the processing in the adhesive coating stage must be kept below 50°C. Above this the curing reaction will start, possibly rendering the adhesive useless for further processing .
  • the silicone is manufactured as an extremely high viscosity paste, which can be extruded or dissolved in solvent to produce a coating compound of manageable viscosity and in one embodiment the base polymer is calendered.
  • the solvent is usually (but not limited to) hydrocarbon solvents - the selection of which must take into account the low processing temperatures needed to prevent initiation of the cross-linking reaction during processing. Consequently, the flash points and evaporation criteria of these solvents must be taken into account when selecting a suitable one or combination.
  • the adhesive system of the preferred embodiment has the solid silicone rubber dispersed in a low boiling point hydrocarbon blend (for example, heptane/hexane) to a solids content of approximately 35%.
  • a low boiling point hydrocarbon blend for example, heptane/hexane
  • the coating is processed to remove the solvent, leaving the uncured rubber adhered to the base coating of standard LSR.
  • a release layer of low density polyethylene (LDPE) film of approximately 50 microns in thickness is applied to protect the adhesive during storage. This film is removed and discarded when the patches have been cut out, exposing the active adhesive layer.
  • LDPE low density polyethylene
  • a patch of the present invention remains fundamentally the same.
  • the patches are designed to either protect or strengthen the bag at those points where stresses may cause that bag to fail.
  • Heat shield patches These protect the bag from the hot gases and particles ejected from the generator during the bag deployment. Heat shield patches are generally found in the bag directly adjacent to the generator outlet, and immediately around the vicinity of the generator anchorage point.
  • Reinforcement patches are found at points in the bag where excessive physical stresses could cause the bag to fail, for example, around those areas where cutouts have been placed in the bag e.g. vent holes (to allow gas egress) and generator inlet holes. These cutouts or apertures are essentially fail points and must be strengthened by addition of extra reinforcing material. Other examples are anchorage points where the bag is attached to the steering wheel or other suitable base. The stresses here are large and extra reinforcement must be provided to prevent the bag tearing away during deployment.
  • the material and/or patches may be suitable for other applications and especially for inflatable articles or pressurised articles.
  • the material 10, in one embodiment, may be for use in a gas distribution tube 62 for use in a vehicle air bag.
  • the material 10 forms a gas distribution tube 62 which facilitates the inflation of the air bag by channelling, directing and distributing the inflation gases in order to influence the speed and manner in which the air bag inflates.
  • the air bag may be any vehicle air bag, for example, a driver bag, passenger bag, side impact bag, inflatable curtain or any other inflatable structure designed to protect and/or restrain the occupant (s) of a vehicle in the event of an impact, collision, roll over situation etc.
  • the material may be used for any suitable part of an air bag.
  • the material is used to form a reinforcing tape which may eliminate the need for sewn seams in cut and sewn air bags.
  • the gas distribution system with an air bag provides a method of distributing the gases of an airbag deployment evenly throughout the bag to ensure uniform inflation. At present, this is achieved using a lance made from either plastic or metal that channels the inflation gases to optimum points along the length thereof.
  • the lance has small holes or slits placed at predetermined points along the length thereof. These predetermined points are usually directly opposite to each inflation chamber contained within the air bag. These chambers expand when the gas from the pyrotechnic (or other) generator fills them. This gas then fills the chambers to provide the cushioning protection for the vehicle occupants in the event of an impact.
  • the material 10 of the present invention is used to created a reinforced fabric tube 62 which thereby reduces the packed volume and also reduces the associated costs.
  • the inflation gases expand the flexible packed tube 62 and apertures 60 (holes or slits) to enable the gases to be directed to the selected optimum areas within the air bag.
  • the tube 62 is constructed from two lengths of silicone rubber coated woven polyamide 6.6 material 50, 56, one of which is the material 10 in accordance with the present invention.
  • the length of the strips 40, 42 are selected by the size and shapes of the respective air bag.
  • a strip 40, 42 is coated on one side with a standard liquid silicone rubber 48, 54 to act as a primer to provide good adhesion for the reactivatable adhesive 46 of the strip comprising the material 10 in accordance with the present invention.
  • the weight and type of the coating may be selected to accommodate higher gas temperatures adjacent to the generator exits as compared to a patch, for example.
  • the material 10 may be primed on one or both sides 48, 52 depending on the end use application and requirements but preferably the weight of the primer 43 on the adhesive side is approximately 25g/m 2 since it one serves to seal the material to prevent over-penetration of the adhesive 46 and to improve the adhesion of the adhesive.
  • the weight of the liquid silicone rubber 52 on the non- adhesive side is determined by the end use requirements.
  • the weight of the adhesive layer 56 is also determined by the end use requirements by may be in excess of 100g/m 2 .
  • the first strip 40 comprises a polyethylene (or other suitable) carrier media, a reactivatable adhesive layer 46, a layer of liquid silicone rubber primer/base coating 48, a layer of a textile 50 and an optional (but preferable) liquid silicone rubber coating 52.
  • the second strip 42 comprises a liquid silicone rubber coating 54, a layer of a textile 56 and an optional (but preferable) liquid silicone rubber coating 58.
  • the two strips 40, 42 of material are joined together by peeling the protective carrier 44 away from the adhesive layer 46 on the material 10 of the strip 42 and then applying the adhesive side of the strip to the primed surface 54 of the second strip 44.
  • This uncured tube is then placed under a hot press (for example, a specially design jig may be used to maintain the tubular cross- section) and heated as necessary to ensure adequate adhesive and cure of the adhesive layer 46 to the primed layer 54.
  • the tube 62 is then removed from the press and allowed to cool.
  • the two strips 40, 42 are cut out as required.
  • the base material strip 42 is twice the width of the adhesive coated material strip 40 but have the same length.
  • the protective carrier film 44 is removed from the adhesive coated strip 40 and this strip 40 is folded over the base material strip 42 to form a conduit or a tubular shape. There is sufficient tack or adhesion to hold the tube in shape whilst the tube is placed under a hot press. The tube is heated and pressed until the adhesive is cured. The tube is removed and allowed to cool after which the gas aggress holes 64 are punched or cut out as required by the end use.
  • the tube 62 has apertures 60 or more specifically gas egress holes 60 punched through the double fabric layer of the tube at those points or locations determined to give the required inflation characteristics for the air bag.
  • the punching of these holes 60 through the double layer gives extra reinforcement to them as provided by the relatively thick layer of silicone adhesive and the two plies of woven material. This prevents the holes 60 from being widened and distorted under stress which may affect the inflation characteristics of the air bag.
  • the first strip 40 locates partially around the outer surface of the second strip 42 in order to form the tube 62.
  • the gap 64 between the inner walls of the tube 62 may be in the region of l-2mm.
  • the holes 60 are punched or cut through both strips 40, 42 forcing the tube 62 at intervals along the length to provide points for gas eggress. These holes 64 provide for uniform inflation of the air bag.
  • the holes 64 are punched through the double layer of material for example through the area that has been laminated, in order to provide for extra reinforcement. This extra reinforcement minimizes the widening or tearing of the holes during inflation whilst the high weight of silicone provides extra thermal protection during inflation.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Air Bags (AREA)

Abstract

The present invention provides a material particularly for use with protective bags for use in vehicles. The material (10) can be produced in bulk in roll form, and cut to any desired shape by the end user and then applied using hot press equipment to the end product or article and, in particular, to a vehicle air bag. The material comprises a silicone adhesive layer (14) applied to one surface thereof. The adhesive has a one part system and is only actuated to cure by actuating means and, specifically heat. Once heated sufficiently (e.g. above 50 °C) the adhesive will cure to secure the material at a desired location.

Description

MATERIAL FOR A PART OF A PROTECTIVE BAG
Field of the Invention
The present invention relates to a material for a part (and especially for patches) of a protective bag for use within a vehicle, patches for applying to articles, a method of producing a material for a part (and especially for patches) of a protective bag for use within a vehicle, a method of forming a material for a part (and especially a patch) of a protective bag for use within a vehicle, a material for a vehicle air bag application and a conduit for use in a vehicle air bag.
Background to the Invention
Air bags for vehicles comprise patches in order to reinforce the bags in particular areas or to provide a heat shield to protect and reinforce the bag at specific locations. Such patches are secured to the material of the air bag by initially applying a wet adhesive to the air bag, for example by using a screen printing method. The patch is then placed on to a machine to apply pressure and heat to the patch to provide a secure attachment of the patch and the air bag. Accordingly, applying the patches can be messy and is time consuming.
Air bags include gas generators which distribute gases into a distribution system within the air bag. Such systems generally comprise substantially rigid lances which can be expensive and/or require a considerable volume especially whilst the air bag is in a packed configuration. It is understood that the air bag may be filled with any suitable gas mixture and the term air bag relates to any gas filled protective bag for a vehicle.
It is an aim of the present invention to overcome at least one problem associated with the prior art whether referred to herein or otherwise.
Summary of the Invention
According to a first aspect of the present invention there is provided a material for a part of a protective bag for use within a vehicle, the material comprising a support material and an adhesive, wherein the adhesive is actuated by actuating means.
Preferably the part of the protective bag is arranged, in use, to be secured to a second part of the protective bag by the adhesive, once actuated.
Preferably the protective bag comprises a vehicle air bag.
The material may form a patch for a vehicle air bag.
The patch may form a strip for a part of vehicle air bag and may form a part of a conduit.
Preferably the adhesive comprises a cross-linkable system.
Preferably the adhesive comprise a one part system.
The adhesive may comprise a two part system. Preferably the actuating means comprises heat.
Preferably the adhesive is actuated at a temperature greater than room temperature.
Preferably the adhesive is actuated at a temperature greater than 40 °C and more preferably greater than 50 °C.
Preferably the actuating means causes the adhesive to cure .
Preferably the material or patch is arranged, in use, to be secured to an inflatable article.
Preferably the material or patch is arranged, in use, to be secured to a vehicle air bag. The material may form at least a part of a vehicle air bag.
Preferably the support material comprises a textile.
Preferably the support material comprises a synthetic material. Preferably the support material comprises a woven material.
Preferably the support material comprises a synthetic polymer. Preferably the synthetic polymer is capable of being drawn into filaments which may be used to produce a yarn which may be capable of being woven and preferably to form a fabric. The support material may be woven with greater than 5 yarns per cm and preferably greater than 10 yarns per cm and more preferably greater than 12 yarns per cm.
The support material may be woven with less than 50 yarns per cm and preferably less than 40 yarns per cm and more preferably less than 30 yarns per cm.
The support material may be coated with a coating material. The coating material may comprise silicone and preferably comprises a liquid silicone rubber. The coating material may comprise an addition curing system.
The addition curing system may be catalysed by a platinum complex.
The coating may be applied to the support material using a knife coating method.
The weight of the coating may be greater than 5 g/m2 and preferably is greater than 8 g/m2 and more preferably is greater than 10 g/m2.
Preferably the support material comprises a polyamide. Preferably the support material comprises polyamide 6.6.
Preferably the adhesive comprises a dry adhesive.
Preferably the adhesive comprises a silicone adhesive.
Preferably the adhesive comprises an addition cure silicone adhesive. Preferably the adhesive comprises a silicone rubber. The adhesive may initially comprise a high viscosity paste.
The adhesive may be dissolved into a solvent for application to the support material.
The adhesive may be extruded for application to the support material.
The solvent may comprise a hydrocarbon solvent. The solvent may comprise an alkane hydrocarbon. The solvent may comprise heptane. The solvent may comprise hexane. The solvent may comprise may comprise a C5 - Cβ alkane hydrocarbon. The solvent may comprise a C6 - C alkane hydrocarbon.
The solvent may comprise toluene.
The solid content of the silicone in the solvent may be greater than 20% and preferably is greater than 30%. The solid content of the silicone in the solvent may be greater than 40% and preferably is greater than 50%. The solid content of the silicone in the solvent may be substantially in the region of 40% to 50%.
The solid content of the silicone in the solvent may be less than 80% and preferably is less than 70%.
The weight of the adhesive in the material may be greater than 10 g/m and preferably is greater than 20 g/m2 and more preferably is greater than 30 g/m2. Preferably the material or patch is arranged to be secured to an article whilst under pressure.
Preferably the material or patch is arranged to be secured to an article in a hot press.
The material may comprise a sealing material. Preferably the sealing material prevents or inhibits the adhesive being absorbed by the support material. Preferably, the sealing material is applied to the support material before the adhesive is applied. The sealing material may comprise silicone and preferably comprises a liquid silicone rubber. The sealing material may comprise greater than 95% silicone and preferably greater than 99% silicone and more preferably comprises 100% silicone.
Preferably the sealing material is only applied to one side of the material and preferably to the side of the material on which the adhesive surface will eventually locate.
The sealing material may be applied by a knife coating method.
The weight of the sealing material may be greater than 5 g/m2 and preferably is greater than 15 g/m2 and more preferably is greater than 20 g/m2.
The weight of the sealing material may be less than 70 g/m2 and preferably is less than 50 g/m2 and more preferably is less than 40 g/m2 Preferably the sealing material comprise an addition curing system. The addition curing system may be catalysed by a platinum complex.
The material may comprise a protective carrier layer. Preferably the protective carrier layer is removable from the material to expose the adhesive surface.
The protective carrier layer may comprise a flexible substrate. The protective carrier layer may comprise paper. The protective carrier layer may comprise a polymer film. The protective carrier layer may comprise a polyethylene film and preferably comprise a low density polyethylene film.
Preferably the - protective carrier layer has low surface energy.
The material may be rolled up and may be rolled on to carrier means, for example on to a tube.
The article may comprise an air bag for a vehicle. The patch may comprise a protective patch for an air bag for a vehicle. The protective patch may comprise a reinforcement patch and/or a thermal shield patch.
The material may form a conduit for fluid flow and preferably forms a part of a tube for gas distribution within a vehicle air bag. The conduit may have apertures defined therein.
The article may comprise a balloon and may comprise a hot air balloon. The adhesive may be reactivatable.
According to a second aspect of the present invention there is provided a patch for applying to an article the patch comprising a material in accordance with the first aspect of the present invention.
The patch may comprise a strip of the material.
The patch may form part of a conduit.
The patch may form part of a gas distribution conduit which preferably is used within a vehicle protective bag.
Preferably the adhesive comprises a cross-linkable system.
Preferably the adhesive comprise a one part system.
The adhesive may comprise a two part system.
The patch is preferably a self adhesive patch.
Preferably the patch is a patch for a vehicle air bag. The patch may be a protective patch. The patch may be a reinforcement patch and/or a heat shield patch.
According to a third aspect of the present invention there is provided a method of producing a material for a part of a protective bag for use within a vehicle comprising locating an adhesive on a support material wherein the adhesive is actuated by actuating means. The method may comprise a method of producing a material for a patch.
Preferably the adhesive comprises a cross-linkable system.
Preferably the adhesive comprise a one part system.
The adhesive may comprise a two part system.
The method may comprise applying a coating to the support material. The method may comprise applying a coating to both sides of the support material.
The material may comprise applying a sealing material on the material. The method may comprise applying a sealing material on one side of the material and preferably on the side to which an adhesive surface will be subsequently located.
The method may comprise applying the adhesive on the sealing material.
The method may comprise applying a protective layer on the material and preferably locating a protective layer over the exposed adhesive surface of the material.
The method may comprise rolling up the material.
The method may comprise cutting the material into patches.
According to a fourth aspect of the present invention there is provided a method of forming a part of a protective bag for use within a vehicle comprising cutting a material wherein the material is in accordance with the first aspect of the present invention.
The method may comprise cutting a patch from the material.
The method may comprise adhering the material to a part of a vehicle air bag.
Preferably the adhesive comprises a cross-linkable system.
Preferably the adhesive comprise a one part system.
The adhesive may comprise a two part system.
According to a fifth aspect of the present invention there is provided a material for a patch to be secured to an article, the material comprising a support material and an adhesive, wherein the adhesive is actuated by actuating means .
The patch may comprise a strip of material.
The article may comprise a vehicle air bag.
Brief Description of the Drawings
The present invention will now be described, by way of example only, with reference to the drawings that follow, in which:
Figure 1 is schematic cross section of a preferred embodiment of the present invention. Figure 2 is a front view of a vehicle air bag with preferred embodiments of patches of the present invention.
Figure 3 is a front view of a vehicle air bag prior to assembly with preferred embodiments of patches of the present invention.
Figure 4 is a front view of another embodiment of a vehicle air bag with preferred embodiments of patches of the present invention.
Figure 5 is a rear view of another embodiment of a vehicle air bag with preferred embodiments of patches of the present invention.
Figure 6 is a plan view of a further embodiment of a first part of a vehicle air bag.
Figure 7 is a schematic cross-section of a further embodiment of a first part of a vehicle air bag.
Figure 8 is a plan view of a further embodiment of a second part of a vehicle air bag.
Figure 9 is a schematic cross-section of a further embodiment of a second part of a vehicle air bag.
Figure 10 is a perspective view of a further embodiment of a part of a vehicle air bag.
Figure 11 is a perspective view of a further embodiment.
Description of the Preferred Embodiments The present invention provides a material 10 for producing patches or other parts which comprise an adhesive 14 provided on a support material 14, as shown in Figure 1. The material 10 can be produced in bulk in roll form, and cut to any desired shape by the end-user or intermediate processor, and then applied using hot press equipment to the end product or article, in particular to a vehicle air bag. The support material 12 comprises a textile. The textile comprises a web of a polyamide and preferably polyamide 6.6. As shown in Figure 1, the support material 12 has a sealing layer 18 provided on at least one surface thereof. The sealing layer 18 prevents or inhibits the adhesive 14 being absorbed by the textile layer 12. The sealing layer 18 comprises silicone and preferably 100% silicone. The textile 12 preferably is coated with a coating 16 material on both sides thereof and is coated by immersing the textile 12 in liquid silicone. The coating strengthens the textile and also prevents or inhibits fluids (for example gases) from passing through the material .
The material 10 has an adhesive 14 applied to one surface thereof. In particular, the material 10 has an adhesive layer 14 on one surface thereof. The adhesive comprises a silicone adhesive and specifically a silicone adhesive with a one part system and is only actuated (or activated) to cure by actuating means (or activating means) , for example, heat. The adhesive does not cure until heated to a temperature greater than 50 °C.
The adhesive layer 14 is tacky at room temperature but would not form a secure bond until heated. Accordingly, the material 10 is provided with a protective layer 20 comprising a film which protects the adhesive layer, for example from grease, dirt, contaminants etc. The film comprises a low density polyethylene.
Accordingly, the material 10 comprises a self adhesive material in which the adhesive will not cure until heated. In addition, in order to provide a secure adhesive between the material and the article to which it is to be secured to, the material is simultaneously heated whilst pressure is applied between the material and the article. The use of heat and pressure ensures a secure bond is formed between the material 10 and the article. The heat and pressure is provided by a standard heat press as used in prior art vehicle air bag applications using wet adhesives.
As previously stated, the present invention is suitable for creating self adhesive patches 24, 26, 32 for vehicle air bags 22, 30 as shown in Figure 2 to 5. In particular, the patches 24, 26, 32 may be reinforcing patches 24, 32 to strengthen the air bag 22, 30 at particular locations, for example in or around apertures 25, 33 and in particular adjacent to the entry aperture 25 or generator aperture and adjacent to vent apertures 32. These patches 24, 32 prevent and inhibit the material of the air bag 22, 30 tearing as a result of the explosive force which the air bag 22, 30 is subjected to during inflation. In addition, the reinforcing patches 24, 32 also protect the air bag material from the temperature of the gas (for example nitrogen) during the explosive inflation of the air bag 22, 30. The patches 24, 26, 32 may either provide protection against tearing or protection against heat or protection against both tearing and heat.
The heat protection patches may be placed at locations in the air bag that will be the subject to the greatest temperature .
In use, the material 10 is provided on a roll with the adhesive surface 14 (or protective layer 20) being on the inner surface. The protective film 20 prevents the material 10 from sticking to itself. Manufacturers can then use their own standard cutting machines and apparatus to cut the patches 24, 26, 32 to the individual shapes required. Accordingly, the manufacturers do not have to produce patches of a particular shape or produce any new cutting apparatus or machines.
Once the patches 24, 26, 32 have been cut into the required shape the patches 24, 26 32 are placed on the surface of the air bag. For this the air bag is turned inside out or are secured prior to stitching the air bag (as shown in Figure 3) such that the patches will eventually be on the internal surface. In alternative embodiments the patches may be on the external surface of the air bag. Figure 2 and Figure 3 illustrate an air bag 22 and in particular a thorax bag in which the edges of the template are stitched to form a seam 27 to complete the air bag whereas Figure 4 (form the vehicle occupants side) and Figure 5 (from the generator/steering wheel side) illustrate a one piece woven air bag 30 which is turned inside out in order for the patch to locate inside the air bag 30. The tacky surface of the adhesive 14 enables the patch 24, 26, 32 to be lightly adhered to the surface such that once the patch is in the correct location, the patch will not easily be accidentally moved out of alignment. Accordingly, the patch 24, 26, 32 does not require the use of a wet adhesive which is normally required and thereby does not require this normal step and/or the screen printing process and apparatus.
Once the patch 24, 26, 32 is loosely adhered to the air bag 22, 30, the air bag is located in a hot press which applies both pressure and heat to the patch. This causes the adhesive to cure and for the patch to be securely attached to the air bag 22, 30.
The patch could be used in other situations other than vehicle air bags 22, 30. For example, patches may be used to create decorative patterns or to display other information on hot air balloons and advertising balloons.
The adhesive 14 is integral with the support material 12 and, therefore, only a single bond is formed between the support material 12 and the material of the article. Wet adhesive and other non-impregnated adhesives effectively form two bonds, one between the adhesive and the material of the article and one between the adhesive and the support material. Accordingly, such securement has an increased risk of failure due to double the number of bonds and also due to the adhesive possibly forming a firm band with one material to the detriment of the other.
Current methods of patch manufacture usually use coated fabric that has been specially produced or has been salvaged from the excess material left over after the airbag cutting stage. Current methods of patch application require the use of a screen-printing method to apply a wet adhesive to the bag, to which the patch is then applied. Heat and pressure are used to bond the patch material to the surface.
The adhesive is usually comprised of a liquid silicone rubber (LSR), which is either addition or peroxide curing. In the case of the former the LSR cures quickly to form good adhesion between the patch and the bag. In the case of the latter, pressure is used to bond the patch but a few days standing time may be required before full adhesion strength is attained.
The present invention does away with the necessity for the adhesive application and metering stages. The patches are cut out as standard and are applied immediately prior to the pressing stage. Heat and pressure are used to bond the patches to the air bag and with full adhesion strength obtained immediately on cooling.
The present invention will now be described in more detail with a description of a preferred arrangement.
The patch comprises a woven synthetic material coated on both sides with silicone rubber. In alternative embodiments, the patches may comprise natural woven fabric materials and in one embodiment may comprise a material incorporating nanotechnology . The support material is polyamide 6.6 but may be any synthetic polymer capable of being drawn into yarn and woven into fabric. The yarn type can be of, but not limited to, 235-, 350-, 470-, 580- or 700-dtex (as these tend to be the standard yarn types offered for airbag applications) , with typical fabric setts ranging from, but not limited to, 12 yarns per cm to 30 yarns per cm. The support layer should be capable of withstanding the elevated temperatures found during the deployment of an airbag (but this is dependent on the end use for the patch) . The patch may be made up in a three- stage process, which comprises : (a) Application of a silicone coating to the face(s) or surface (s) of the support material. This provides protection to the patch support material. However in some cases, this face coating may be omitted dependent on the use and position of the patch within the air bag. Also, if the patch is intended for a non-airbag application e.g. balloon patch, then this face coating may be unnecessary. The silicone coating can be applied using spreading techniques such as knife coating, but the end technique is very dependent on the mass of coating required and the coater's equipment. Any suitable coating equipment may be used. Typical weights for the protective face coating can range from 10g/m2 upwards .
The silicone coating on the face usually comprises a liquid silicone rubber that uses addition-curing systems primarily of the type catalysed by platinum complexes. Typical examples could be the systems offered by Wacker-Chemie GmbH, Dow Corning Corporation or Rhodia Silicones, examples of which could be Elastosil LR6251F (Wacker) , DC3625 (Dow Corning) and Rhodorsil TCS7534 (Rhodia) .
(b) Application of a base coating or sealing layer on the adhesive side of the patch. This helps seal the surface of the fabric, potentially allowing a lower weight of adhesive to be applied. The application of a base coat is particularly effective on woven fabrics that have a more open construction, or that use a higher decitex yarn.
Here the adhesive may penetrate into the interstices of the weave which has the effect of leaving less adhesive available for chemical and mechanical adhesion to the surface being bonded to. This pre-coating of the fabric prevents this penetration and tests have found that adhesion is much improved when a base coat is used.
Again, the silicone coating can be applied using spreading techniques such as knife coating, but the end technique is very dependent on the mass of coating required and the coater's equipment. Any suitable coating equipment may be used. In order to get effective sealing of the surface, typical weights for the base coating can range from 20-
40g/m2.
Again, the silicone base coating usually comprises of an LSR (Liquid Silicone Rubber) that uses addition-curing systems primarily of the type catalysed by platinum complexes. Typical examples could be the systems offered by Wacker-Chemie GmbH, Dow Corning Corporation or Rhodia Silicones, examples of which could be Elastosil LR6251F (Wacker) , DC3625 (Dow Corning) and Rhodorsil TCS7534 (Rhodia) . (c) Application of the adhesive coating onto the base coating. The silicone coating can be applied using spreading techniques such as knife coating, but the end technique is very dependent on the mass of coating required and the coater's equipment. Any suitable coating equipment may be used. Typical weights for the adhesive coating can range from 30g/m2 upwards, but this is very dependent on the weave and construction of both the support material of the patch and the material being bonded to. For example, a patch constructed of a 700-dtex support material of 15 x 15 yarns/cm being bonded to a fabric of similar type would require significantly more adhesive than a patch constructed of a 235-dtex material of 28 yarns/cm as the 235-dtex material is much flatter.
The silicone that has been used for the adhesive layer is an addition curing system that has been specially modified to be a one-pack system rather than the standard two-pack systems. The curing system has been inhibited so that the cross- linking mechanism only occurs when the temperature of the system is raised for example by actuating means. One example of this system is Elastosil R Plus 4001/40MH produced by Wacker, dispersed in a suitable hydrocarbon solvent. One example of a dispersion of this rubber in solvent is commercially available as SLM45578 or SLM45579 (also from Wacker) .
(d) Application of a protective carrier layer to the adhesive layer to protect it from damage and also to prevent transfer of the adhesive when the patch material is in roll form or during further processing e.g. cutting patches out at the production stage.
This layer can be any flexible substrate e.g. paper, polymer film, which is either treated (or has existing inherent properties that allow it) to provide a surface of surface energy low enough to provide a clean release of the adhesive layer from it when the user requires. The preferred material is a low-density polyethylene film seems to provide such properties at a relatively low cost. The protective carrier layer must be introduced before the material is reeled up into a roll form.
A cross sectional view of a preferred embodiment of the invention is shown in Figure 1.
Both the face coat silicone (coating material) and the base coat (sealing material) on the adhesive layer side are, as previously discussed, standard addition cure liquid silicone rubbers of the type used currently to produce coated materials for airbag applications. These are provided by the likes of Dow Corning, Wacker-Chemie, Rhodia and GE-Bayer Silicones. These are two-part systems in which the cross-linking agent (H-siloxane) is contained in one component, and the catalyst (the platinum complex) is contained in the other. Both components are stable until mixed, at which point cross-linking occurs. The cross-linking reaction is accelerated by the addition of energy (usually in the form of heat) , which is why these systems are usually cured at elevated temperatures. The catalyst is usually inhibited to some degree to prevent fast cure at lower temperatures (hence extending the pot life) but even so, the reaction will proceed slowly at room temperature and mixed systems will cure albeit over days rather than minutes or seconds.
The adhesive used in the present invention however is a one-part system, with all the necessary components required for curing contained in this one part. However the system is inhibited so the catalyst will not become effective until a certain temperature is reached. This renders the silicone rubber stable until required, enabling it to be coated onto substrates without setting off the curing reaction. However, the temperature during the processing in the adhesive coating stage must be kept below 50°C. Above this the curing reaction will start, possibly rendering the adhesive useless for further processing .
The silicone is manufactured as an extremely high viscosity paste, which can be extruded or dissolved in solvent to produce a coating compound of manageable viscosity and in one embodiment the base polymer is calendered. The solvent is usually (but not limited to) hydrocarbon solvents - the selection of which must take into account the low processing temperatures needed to prevent initiation of the cross-linking reaction during processing. Consequently, the flash points and evaporation criteria of these solvents must be taken into account when selecting a suitable one or combination.
The adhesive system of the preferred embodiment has the solid silicone rubber dispersed in a low boiling point hydrocarbon blend (for example, heptane/hexane) to a solids content of approximately 35%. The coating is processed to remove the solvent, leaving the uncured rubber adhered to the base coating of standard LSR. A release layer of low density polyethylene (LDPE) film of approximately 50 microns in thickness is applied to protect the adhesive during storage. This film is removed and discarded when the patches have been cut out, exposing the active adhesive layer.
Different air bags for different applications in the vehicle require individually designed and placed patches. However, a patch of the present invention remains fundamentally the same. The patches are designed to either protect or strengthen the bag at those points where stresses may cause that bag to fail. These could be for any number of reasons but basic examples are:
(a) Heat shield patches These protect the bag from the hot gases and particles ejected from the generator during the bag deployment. Heat shield patches are generally found in the bag directly adjacent to the generator outlet, and immediately around the vicinity of the generator anchorage point.
(b) Reinforcement patches are found at points in the bag where excessive physical stresses could cause the bag to fail, for example, around those areas where cutouts have been placed in the bag e.g. vent holes (to allow gas egress) and generator inlet holes. These cutouts or apertures are essentially fail points and must be strengthened by addition of extra reinforcing material. Other examples are anchorage points where the bag is attached to the steering wheel or other suitable base. The stresses here are large and extra reinforcement must be provided to prevent the bag tearing away during deployment. The material and/or patches may be suitable for other applications and especially for inflatable articles or pressurised articles.
As shown in Figures 6 to 11, the material 10, in one embodiment, may be for use in a gas distribution tube 62 for use in a vehicle air bag. In particular, the material 10 forms a gas distribution tube 62 which facilitates the inflation of the air bag by channelling, directing and distributing the inflation gases in order to influence the speed and manner in which the air bag inflates. The air bag may be any vehicle air bag, for example, a driver bag, passenger bag, side impact bag, inflatable curtain or any other inflatable structure designed to protect and/or restrain the occupant (s) of a vehicle in the event of an impact, collision, roll over situation etc.
The material may be used for any suitable part of an air bag.
In one further embodiment, the material is used to form a reinforcing tape which may eliminate the need for sewn seams in cut and sewn air bags.
The gas distribution system with an air bag provides a method of distributing the gases of an airbag deployment evenly throughout the bag to ensure uniform inflation. At present, this is achieved using a lance made from either plastic or metal that channels the inflation gases to optimum points along the length thereof. The lance has small holes or slits placed at predetermined points along the length thereof. These predetermined points are usually directly opposite to each inflation chamber contained within the air bag. These chambers expand when the gas from the pyrotechnic (or other) generator fills them. This gas then fills the chambers to provide the cushioning protection for the vehicle occupants in the event of an impact.
Current lances are relatively expensive and also increase the packed volume of the bag. The material 10 of the present invention is used to created a reinforced fabric tube 62 which thereby reduces the packed volume and also reduces the associated costs. The inflation gases expand the flexible packed tube 62 and apertures 60 (holes or slits) to enable the gases to be directed to the selected optimum areas within the air bag. The tube 62 is constructed from two lengths of silicone rubber coated woven polyamide 6.6 material 50, 56, one of which is the material 10 in accordance with the present invention. The length of the strips 40, 42 are selected by the size and shapes of the respective air bag.
A strip 40, 42 is coated on one side with a standard liquid silicone rubber 48, 54 to act as a primer to provide good adhesion for the reactivatable adhesive 46 of the strip comprising the material 10 in accordance with the present invention. The weight and type of the coating may be selected to accommodate higher gas temperatures adjacent to the generator exits as compared to a patch, for example.
The material 10 may be primed on one or both sides 48, 52 depending on the end use application and requirements but preferably the weight of the primer 43 on the adhesive side is approximately 25g/m2 since it one serves to seal the material to prevent over-penetration of the adhesive 46 and to improve the adhesion of the adhesive. The weight of the liquid silicone rubber 52 on the non- adhesive side is determined by the end use requirements.
The weight of the adhesive layer 56 is also determined by the end use requirements by may be in excess of 100g/m2.
Briefly, the first strip 40, comprises a polyethylene (or other suitable) carrier media, a reactivatable adhesive layer 46, a layer of liquid silicone rubber primer/base coating 48, a layer of a textile 50 and an optional (but preferable) liquid silicone rubber coating 52. The second strip 42 comprises a liquid silicone rubber coating 54, a layer of a textile 56 and an optional (but preferable) liquid silicone rubber coating 58.
The two strips 40, 42 of material are joined together by peeling the protective carrier 44 away from the adhesive layer 46 on the material 10 of the strip 42 and then applying the adhesive side of the strip to the primed surface 54 of the second strip 44. This uncured tube is then placed under a hot press (for example, a specially design jig may be used to maintain the tubular cross- section) and heated as necessary to ensure adequate adhesive and cure of the adhesive layer 46 to the primed layer 54. The tube 62 is then removed from the press and allowed to cool.
The two strips 40, 42 are cut out as required. In this embodiment, the base material strip 42 is twice the width of the adhesive coated material strip 40 but have the same length. The protective carrier film 44 is removed from the adhesive coated strip 40 and this strip 40 is folded over the base material strip 42 to form a conduit or a tubular shape. There is sufficient tack or adhesion to hold the tube in shape whilst the tube is placed under a hot press. The tube is heated and pressed until the adhesive is cured. The tube is removed and allowed to cool after which the gas aggress holes 64 are punched or cut out as required by the end use.
The tube 62 has apertures 60 or more specifically gas egress holes 60 punched through the double fabric layer of the tube at those points or locations determined to give the required inflation characteristics for the air bag. The punching of these holes 60 through the double layer gives extra reinforcement to them as provided by the relatively thick layer of silicone adhesive and the two plies of woven material. This prevents the holes 60 from being widened and distorted under stress which may affect the inflation characteristics of the air bag.
The first strip 40 locates partially around the outer surface of the second strip 42 in order to form the tube 62. The gap 64 between the inner walls of the tube 62 may be in the region of l-2mm. The holes 60 are punched or cut through both strips 40, 42 forcing the tube 62 at intervals along the length to provide points for gas eggress. These holes 64 provide for uniform inflation of the air bag. The holes 64 are punched through the double layer of material for example through the area that has been laminated, in order to provide for extra reinforcement. This extra reinforcement minimizes the widening or tearing of the holes during inflation whilst the high weight of silicone provides extra thermal protection during inflation.
Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification
(including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A material for a part of a protective bag for use within a vehicle, the material comprising a support material and an adhesive, wherein the adhesive is actuated by actuating means.
2. A material according to claim 1 in which the protective bag comprises a vehicle air bag.
3. A material according to claim 2 in which the material forms a patch for a vehicle air bag. . A material according to any preceding claim in which the patch forms a strip for a part of a conduit.
5. A material according to any preceding claim in which the adhesive comprises a cross-linkable system.
6. A material according to any preceding claim in which the adhesive comprise a one part system.
7. A material according to any one of claims 1 to 5 in which the adhesive comprises a two part system.
8. A material according to any preceding claim in which the actuating means comprises heat.
9. A material according to claim 8 in which the adhesive is actuated at a temperature greater than room temperature .
10. A material according to claim 9 in which the adhesive is actuated at a temperature greater than 40 °C.
11. A material according to any preceding claim in which the actuating means causes the adhesive to cure.
12. A material according to any preceding claim in which the material forms at least a part of a vehicle air bag.
13. A material according to any preceding claim in which the support material comprises a textile.
14. A material according to any preceding claim in which the support material comprises a synthetic polymer.
15. A material according to any preceding claim in which the support material is woven with greater than 12 yarns per cm.
16. A material according to any preceding claim in which the support material is coated with a coating material.
17. A material according to claim 16 in which the coating material comprises a liquid silicone rubber.
18. A material according to claim 16 or claim 17 in which the coating material comprises an addition curing system.
19. A material according to claim 18 in which the addition curing system is catalysed by a platinum complex.
20. A material according to any preceding claim in which the support material comprises a polyamide.
21. A material according to any preceding claim in which the adhesive comprises a dry adhesive.
22. A material according to any preceding claim in which the adhesive comprises an addition cure silicone adhesive.
23. A material according to any preceding claim in which the adhesive is dissolved into a solvent for application to the support material.
24. A material according to claim 23 in which the solvent comprises a hydrocarbon solvent.
25. A material according to claim 23 or claim 24 in which the solvent comprises toluene.
26. A material according to any one of claims 22 to 24 in which the solid content of the silicone in the solvent is substantially in the region of 40% to 50%.
27. A material according to any preceding claim in which the material is arranged to be secured to an article whilst under pressure.
28. A material according to any preceding claim in which the material or patch is arranged to be secured to an article in a hot press.
29. A material according to any preceding claim in which the material comprises a sealing material.
30. A material according to claim 29 in which the sealing, material prevents or inhibits the adhesive being absorbed by the support material.
31. A material according to claim 29 or claim 30 in which the sealing material comprises 100% silicone.
32. A material according to any preceding claim in which the material comprises a protective carrier layer.
33. A material according to claim 32 in which the protective carrier layer is removable from the material to expose the adhesive surface.
34. A material according to any preceding claim in which the material forms a conduit for fluid flow.
35. A patch for applying, to an article the patch comprising a material in accordance with any preceding claim.
36. A patch according to claim 35 in which the patch is a self adhesive patch.
37. A patch according to claim 35 or claim 36 in which the patch is a patch for a vehicle air bag.
38. A method of producing a material for a part of a protective bag for use within a vehicle comprising locating an adhesive on a support material wherein the adhesive is actuated by actuating means.
39. A method of forming a part of a protective bag for use within a vehicle comprising cutting a material wherein the material is in accordance with any one of claims 1 to 34.
40. An air bag for use within a vehicle including at least a part bej.ng formed of a material wherein the material is in accordance with any one of claims 1 to 34.
41. A material for a patch to be secured to an article, the material comprising a support material and an adhesive, wherein the adhesive is actuated by actuating means .
42. A material substantially as herein described, with reference to, and as shown in any of the accompanying drawings .
43. A part of an air bag substantially as herein described, with reference to, and as shown in any of the accompanying drawings.
44. An air bag substantially as herein described, with reference to, and as shown in any of the accompanying drawings .
PCT/GB2004/003776 2003-09-05 2004-09-03 Material for a part of a protective bag WO2005023601A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB0320836.0A GB0320836D0 (en) 2003-09-05 2003-09-05 Material
GB0320836.0 2003-09-05

Publications (1)

Publication Number Publication Date
WO2005023601A1 true WO2005023601A1 (en) 2005-03-17

Family

ID=29226569

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2004/003776 WO2005023601A1 (en) 2003-09-05 2004-09-03 Material for a part of a protective bag

Country Status (2)

Country Link
GB (1) GB0320836D0 (en)
WO (1) WO2005023601A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8287685B2 (en) 2006-12-06 2012-10-16 Dow Corning Corporation Airbag and process for its assembly
WO2012168237A1 (en) * 2011-06-08 2012-12-13 Takata AG Airbag for a vehicle occupant restraint system and method for producing an airbag

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0347748A (en) * 1989-07-14 1991-02-28 Nitto Denko Corp Sealing tape for waterproof cloth
WO1998012075A1 (en) * 1996-09-18 1998-03-26 Minnessota Mining And Manufacturing Company Adhesively-bonded inflatable restraint and method of making

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0347748A (en) * 1989-07-14 1991-02-28 Nitto Denko Corp Sealing tape for waterproof cloth
WO1998012075A1 (en) * 1996-09-18 1998-03-26 Minnessota Mining And Manufacturing Company Adhesively-bonded inflatable restraint and method of making

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 199115, Derwent World Patents Index; Class A14, AN 1991-105884, XP002310401 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8287685B2 (en) 2006-12-06 2012-10-16 Dow Corning Corporation Airbag and process for its assembly
WO2012168237A1 (en) * 2011-06-08 2012-12-13 Takata AG Airbag for a vehicle occupant restraint system and method for producing an airbag
CN103476639A (en) * 2011-06-08 2013-12-25 高田股份公司 Airbag for a vehicle occupant restraint system and method for producing an airbag
CN103476639B (en) * 2011-06-08 2016-05-25 高田股份公司 Be used for the air bag of vehicle occupant restraint system and the method for the manufacture of air bag

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