Abstract:
An airbag. The airbag includes a heat shield made of a thermal resistant material that prevents a pyrotechnic inflator&#39;s clinkers and hot gas from damaging the airbag or injuring the vehicle occupant. The thermal resistant material is a base fabric web with an elastomeric coating that includes a high aspect ratio additive such as vitreous fibers of alumina silicates. The resulting thermal resistant material exhibits exceptionally good thermal resistance times while, at the same time, uses relatively low coating weights.

Description:
BACKGROUND 
     (1) Field 
     The present invention relates generally to vehicle airbags and, more particularly, to a coating that imparts high thermal resistance to an airbag&#39;s heat shield. 
     (2) Related Art 
     Airbags are used in the automotive industry to protect vehicle occupants in the event of an accident. An airbag system typically includes a sensor, inflator, airbag and cover. When the sensor is set off, for example in the event of an accident, the inflator is activated, and fills the airbag with gas. The airbag comes from behind (or through) the cover when inflated, thereby placing a cushion between the occupant and the potentially harmful vehicle surface. These events must occur within milliseconds to effectively protect the occupant. 
     Inflators are generally classified as cold-gas types, which release compressed gas, or pyrotechnic types, which burn a generant such as sodium azide or alkali metal azide. Combustion types are desirable because the generants&#39; burn rates are controllable and reproducible, and therefore the devices are quite reliable. Combustion types also tend to be smaller, weigh less and be less expensive than compressed gas inflators. 
     Combustion inflators propel not only hot gas but also “clinkers,” which are by-product particulates such as sulfur metals and sodium azide. These clinkers are propelled at approximately 90 meters per second, at 450-1000° C. These projectiles can burn holes in the airbag, which is typically made of nylon or a similar fabric, and can lead to decreased airbag efficacy or burn injuries to the occupant. So called “filtered combustion inflators” attempt to prevent clinker-related problems by introducing a filter into the gas stream which inhibits clinkers from entering the airbag itself. However, filters are an imperfect solution given they slow the inflation rate, introduce another part into the system that could lead to failure, add weight and volume to the system, and cost more. 
     “Unfiltered combustion inflators” or “hot unfiltered inflators” are very desirable in the industry because they are reliable, small, light and relatively inexpensive. However, since they do not have filters, the clinkers spew out of the inflator with the inflating gas. Hot clinkers can compromise the integrity of an airbag by melting or burning through the airbag material, thereby causing under inflation or premature deflation. 
     Accordingly, various treatments and devices have been tried to lessen the negative impact of clinkers in airbags used with hot unfiltered inflators. Specifically, airbags have been treated with inside coatings of heat resistant material such as neoprene, silicone resin, silicone rubber, fluororesin such as PFA, various poly-resins, expanded graphite and intumescent material. Alternatively, liners have been employed using materials such as aluminized silica cloth and expandable fiberglass. Also, independent heat shields have been introduced made of materials such as stamped steel, aromatic polyamide fiber such as Kevlar®, as well as nylon, polyester and fiberglass coated with neoprene, silicone or poly-vinyl chloride. Finally, deflectors have also been made of the same material as the airbag. 
     While the aforementioned improvements are useful, they remain less than ideal. Specifically, airbags with a treated inside surface are still susceptible to burn-through by projectile clinkers because known coatings provide limited protection when applied thinly but a thickly applied coating defeats the safety system&#39;s overall goal of being lightweight and occupying a small volume. Liners are also problematic because they introduce more bulk and weight to the airbag. The independent shields and deflectors are likewise limited in that they are either unacceptably bulky or not bulky but provide only limited protection. 
     Thus, there remains a need for a new and improved vehicle safety device, airbag, heat shield and coating that exhibit improved thermal resistance values while, at the same time, is both low volume and low weight. 
     SUMMARY OF THE INVENTIONS 
     The present inventions are directed to a vehicle safety device with significantly improved thermal resistance, yet is economical, efficacious, low volume and low weight. In use, the inventions protect the airbag and vehicle occupant from clinkers. 
     This is accomplished by providing a vehicle safety device including an airbag and heat shield, with the heat shield having a thermal resistance value of greater than 120 seconds at 450° C., when using a coating weight less than other known coatings. 
     Another aspect of the inventions is to provide a heat shield for an air bag including a base fabric web with a coating that includes a high aspect ratio thermally resistant additive. 
     Yet another aspect of the inventions is to provide an airbag including a heat shield, with the heat shield having a base fabric web and a coating, with the coating including a high aspect ratio thermally resistant additive that imparts onto the heat shield a thermal resistance value of greater than 120 seconds at 450° C. and including an inflator in communication with the airbag and heat shield. 
     Still another aspect of the inventions is to provide a method of producing a thermally resistant material wherein a high aspect ratio additive is added to both Component A and Component B, then Component A and Component B are combined to make a coating, which is applied to a base fabric web. 
     These and other functions of the present inventions will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  depicts a top perspective view of a heat shield inside an airbag constructed according to the present inventions; 
         FIG. 2  schematically represents the path of air and clinkers from an inflator to an airbag and heat shield, shown in perspective; 
         FIG. 3  is perspective side view of a heat shield with a connected attachment plate; 
         FIG. 4  is a cross sectional perspective view taken along lines  4 - 4  of  FIG. 1  showing orientation of an airbag, heat shield and attachment plate; 
         FIG. 5  is a cross sectional view generally taken along lines  5 - 5  of  FIG. 4 , except showing an entire cross section of an airbag and heat shield; 
         FIG. 6  is a depiction of a vehicle safety device in use; 
         FIG. 7  is a schematic top view of a base fabric and coating with additive; 
         FIG. 8  is a cross sectional view of a base fabric and coating with additive, taken along line  8 - 8  of  FIG. 7 ; 
         FIG. 9  diagrams some major steps of making a thermal resistant material; 
         FIG. 10  graphically represents the thermal resistance profiles of various coatings tested at 450° C.; 
         FIG. 11  graphically represents the thermal resistance profiles of various coatings tested at 550° C.; 
         FIG. 12  graphically represents the thermal resistance profiles of various coatings tested at 650° C.; 
         FIG. 13  graphically represents the thermal resistance profiles of various coatings tested at 750° C.; and 
         FIG. 14  graphically represents the thermal resistance profiles of one embodiment at 1000° C. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description, like reference characters designate like or corresponding parts throughout the several views. 
     Referring now to the drawings, it will be understood that the illustrations are for the purpose of describing a preferred embodiment of the inventions and are not intended to limit the inventions thereto. The major components of vehicle safety device  10  are shown in  FIG. 1 , and include airbag  20 , heat shield  30  (shown in phantom lines) and attachment plate  34  (shown in phantom). Vehicle safety device  10  protects vehicle passengers by providing a cushioning airbag  20 , which is inflated through inlet  42 . Heat shield  30  protects airbag  20  by deflecting gas  60  and clinkers (particulates)  61  coming from inflator  15 . 
       FIG. 2  schematically represents the journey of gas  60  and clinkers  61  from inflator  15  into vehicle safety device  10 . Specifically, gas  60  and clinkers  61  are expelled from inflator  15 , pass through inlet  42 , and enter heat shield  30 . Gas  60  travels through ducts  44  to inflate airbag  20 . Inflator  15  is in fluid communication with inlet  42 , heat shield  30 , and airbag  20 . 
       FIG. 3  further depicts heat shield  30 , which defines inlet  42 , through which gas  60  and clinkers  61  enter, and ducts  44 , through which gas  60  exits. Upon inflation, clinkers  61  are substantially retained within heat shield  30 , with a substantial number of clinkers  61  bouncing off deflecting surface  46 , which includes coating  58 , and coming to rest within heat shield  30 . Even when clinkers  61  do not come to rest within heat shield  30 , they are delayed in reaching airbag  20 , and therefore are cooler when they arrive. This orientation lessens the risk that clinkers  61  or hot gas  60  will damage airbag  20  or injure occupant. 
       FIG. 4  shows the orientation of layers with airbag  20  on top, heat shield  30  underneath, and attachment plate  34  underneath that. These three layers individually and collectively define inlet  42 . 
     As best shown in  FIG. 5 , airbag  20  and heat shield  30  are preferably separate pieces, with heat shield  30  fitting within airbag  20  and connecting to each other by attachment plate  34 . Preferably, attachment plate  34  includes fasteners  36 , which protrude through shield fastener openings  32  and bag fastener openings  22  for connecting air bag  20  and heat shield  30 . 
     In the event of an accident, inflator  15  is activated and combustion occurs. As shown in  FIG. 6 , inflated airbag  20  “breaks through” cover  12 . Airbag  20  integrity is maintained because heat shield  30  has effectively protected it. 
     Heat shield  30  has a thermal resistance value of greater than 120 seconds at 450° C. Thermal resistance value, also known as the “burn-through rate” or “thermal resistivity” is the time it takes for a slug at a given temperature to burn through a given material. Thermal resistance values reported herein were determined using the “Hot Rod Thermal Resistance Tester.” Specifically, a type 304 stainless the cylindrical rod (the “penetrator”) with a diameter and length of ½ and 2 inches respectively is heated to a given temperature, typically 450, 550, 650 and 750° C. 
     In one test, a heated penetrator is positioned 5.25 inches above a test sample of fabric that is held taut in a “penetration unit”, then the penetrator is allowed to drop so the end of the cylinder contacts the fabric sample. Sensors start a timer when the cylinder contacts the fabric and stop the timer when the cylinder passes through the fabric. The amount of time the heated cylinder is resting on the fabric is the measurement of the “thermal resistance” of the fabric to clinkers. A thermal resistance time of greater than 120 seconds is widely considered the best possible rating since the penetrator (or clinkers) will have sufficiently cooled after 120 seconds, thereby making it highly unlikely it would burn through the test material in greater than 120 seconds. 
     While the thermal resistance time is crucial, it has to also be viewed within the context of the weight of coating required to achieve a given thermal resistance time. Specifically, a low coating weight and a high thermal resistance time are most desirable. 
     As shown in  FIG. 5 , heat shield  30  includes base fabric web  52  and coating  58  applied, at least, in a thin layer to the inward facing surface of heat shield  30 . Fabric web  52  is preferably formed from synthetic fibers  57  ( FIG. 7 ) between about 300 denier and about 900 denier. Unless otherwise noted, “about” as used herein, means within 5%. Preferably, fibers  57  are nylon, polyester, acrylic or a combination of some or all of those. Most preferably, the fibers are high tenacity nylon 66 available from Invista of Kingston, Ontario, Canada. Base fabric web  52  preferably weighs between about 4 and 8 ounces per square yard (osy). Preferably, about 1 to about 6 ounces of coating  58  are applied per square yard of fabric web  52 , with about 2 ounces per square yard being most preferred. The orientation of coating  58  including additive  56  to fabric web  52  is generally shown in  FIGS. 7 and 8 . 
     Coating  58  is preferably elastomeric, with a polymeric silicone elastomer being more preferred, and a room temperature vulcanizing polymeric silicone elastomer, such as X832-394 available from Shin Etsu being most preferred. 
     Coating  58  imparts the best thermal resistance to base fabric, at the lowest coating weight, when compared to no coating or conventional coatings. This superior performance occurred at all tested temperatures. This data is reported in Table 1, and graphically represented at various temperatures in  FIGS. 10-14 . 
     
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 THERMAL RESISTANCE OF VARIOUS COATINGS AT 
               
               
                 VARIOUS AMOUNTS AT VARIOUS TEMPERATURES 
               
             
          
           
               
                   
                 TOTAL 
                 GRIEGE OF 
                 TYPE OF 
                 TEST 
                 COATING 
                 THERMAL 
               
               
                 SAMPLE 
                 WEIGHT 
                 FABRIC 
                 COATING + 
                 TEMP 
                 WEIGHT 
                 RESISTANCE 
               
               
                 ID 
                 (osy) 
                 (osy) 
                 ADDITIVE 
                 (Celsius) 
                 (osy) 
                 (seconds) 
               
               
                   
               
             
          
           
               
                 1 
                 6.76 
                 5.44 
                 SbO5 
                 450 
                 1.32 
                 3.18 
               
               
                 2 
                 7.95 
                 5.44 
                 SbO5 
                 450 
                 2.51 
                 8.90 
               
               
                 3 
                 9.27 
                 5.44 
                 SbO5 
                 450 
                 3.83 
                 120.00 
               
               
                 4 
                 10.52 
                 5.44 
                 SbO5 
                 450 
                 5.08 
                 120.00 
               
               
                 5 
                 6.91 
                 5.44 
                 Expandable 
                 450 
                 1.47 
                 5.09 
               
               
                   
                   
                   
                 graphite 
               
               
                 6 
                 7.75 
                 5.44 
                 Expandable 
                 450 
                 2.31 
                 15.00 
               
               
                   
                   
                   
                 graphite 
               
               
                 7 
                 8.74 
                 5.44 
                 Expandable 
                 450 
                 3.30 
                 120.00 
               
               
                   
                   
                   
                 graphite 
               
               
                 8 
                 10.08 
                 5.44 
                 Expandable 
                 450 
                 4.64 
                 120.00 
               
               
                   
                   
                   
                 graphite 
               
               
                 9 
                 7.19 
                 5.44 
                 LSR ONLY 
                 450 
                 1.75 
                 6.22 
               
               
                 10 
                 7.43 
                 5.44 
                 LSR ONLY 
                 450 
                 1.98 
                 7.08 
               
               
                 11 
                 7.92 
                 5.44 
                 LSR ONLY 
                 450 
                 2.47 
                 120.00 
               
               
                 12 
                 8.36 
                 5.44 
                 LSR ONLY 
                 450 
                 2.90 
                 120.00 
               
               
                 13 
                 8.80 
                 5.44 
                 LSR ONLY 
                 450 
                 3.34 
                 120.00 
               
               
                 14 
                 9.52 
                 5.44 
                 LSR ONLY 
                 450 
                 4.07 
                 120.00 
               
               
                 15 
                 6.83 
                 5.44 
                 20% SLAG 
                 450 
                 1.39 
                 4.63 
               
               
                 16 
                 7.13 
                 5.44 
                 20% SLAG 
                 450 
                 1.69 
                 7.77 
               
               
                 17 
                 7.43 
                 5.44 
                 20% SLAG 
                 450 
                 1.99 
                 54.97 
               
               
                 18 
                 7.70 
                 5.44 
                 20% SLAG 
                 450 
                 2.26 
                 120.00 
               
               
                 19 
                 8.13 
                 5.44 
                 20% SLAG 
                 450 
                 2.69 
                 120.00 
               
               
                 20 
                 8.77 
                 5.44 
                 20% SLAG 
                 450 
                 3.33 
                 120.00 
               
               
                 21 
                 9.67 
                 5.44 
                 20% SLAG 
                 450 
                 4.23 
                 120.00 
               
               
                 22 
                 6.73 
                 5.44 
                 SbO5 
                 550 
                 1.29 
                 1.14 
               
               
                 23 
                 8.18 
                 5.44 
                 SbO5 
                 550 
                 2.74 
                 5.13 
               
               
                 24 
                 9.19 
                 5.44 
                 SbO5 
                 550 
                 3.75 
                 8.13 
               
               
                 25 
                 10.40 
                 5.44 
                 SbO5 
                 550 
                 4.96 
                 6.28 
               
               
                 26 
                 6.86 
                 5.44 
                 Expandable 
                 550 
                 1.42 
                 3.06 
               
               
                   
                   
                   
                 graphite 
               
               
                 27 
                 7.66 
                 5.44 
                 Expandable 
                 550 
                 2.26 
                 6.09 
               
               
                   
                   
                   
                 graphite 
               
               
                 28 
                 8.73 
                 5.44 
                 Expandable 
                 550 
                 3.29 
                 10.63 
               
               
                   
                   
                   
                 graphite 
               
               
                 29 
                 9.99 
                 5.44 
                 Expandable 
                 550 
                 4.55 
                 22.60 
               
               
                   
                   
                   
                 graphite 
               
               
                 30 
                 6.91 
                 5.44 
                 LSR ONLY 
                 550 
                 1.47 
                 2.30 
               
               
                 31 
                 7.19 
                 5.44 
                 LSR ONLY 
                 550 
                 1.75 
                 2.81 
               
               
                 32 
                 7.43 
                 5.44 
                 LSR ONLY 
                 550 
                 1.99 
                 3.08 
               
               
                 33 
                 7.92 
                 5.44 
                 LSR ONLY 
                 550 
                 2.48 
                 4.95 
               
               
                 34 
                 8.36 
                 5.44 
                 LSR ONLY 
                 550 
                 2.92 
                 8.57 
               
               
                 35 
                 8.80 
                 5.44 
                 LSR ONLY 
                 550 
                 3.36 
                 28.83 
               
               
                 36 
                 9.52 
                 5.44 
                 LSR ONLY 
                 550 
                 4.08 
                 108.03 
               
               
                 37 
                 6.83 
                 5.44 
                 20% SLAG 
                 550 
                 1.39 
                 2.21 
               
               
                 38 
                 7.17 
                 5.44 
                 20% SLAG 
                 550 
                 1.73 
                 2.71 
               
               
                 39 
                 7.50 
                 5.44 
                 20% SLAG 
                 550 
                 2.06 
                 4.48 
               
               
                 40 
                 7.73 
                 5.44 
                 20% SLAG 
                 550 
                 2.29 
                 4.97 
               
               
                 41 
                 8.20 
                 5.44 
                 20% SLAG 
                 550 
                 2.76 
                 47.77 
               
               
                 42 
                 8.80 
                 5.44 
                 20% SLAG 
                 550 
                 3.36 
                 120.00 
               
               
                 43 
                 9.77 
                 5.44 
                 20% SLAG 
                 550 
                 4.33 
                 120.00 
               
               
                 44 
                 6.77 
                 5.44 
                 SbO5 
                 650 
                 1.33 
                 1.41 
               
               
                 45 
                 8.15 
                 5.44 
                 SbO5 
                 650 
                 2.71 
                 2.69 
               
               
                 46 
                 9.06 
                 5.44 
                 SbO5 
                 650 
                 3.62 
                 3.89 
               
               
                 47 
                 10.50 
                 5.44 
                 SbO5 
                 650 
                 5.06 
                 6.78 
               
               
                 48 
                 6.47 
                 5.44 
                 Expandable 
                 650 
                 1.03 
                 1.58 
               
               
                   
                   
                   
                 graphite 
               
               
                 49 
                 7.66 
                 5.44 
                 Expandable 
                 650 
                 2.22 
                 3.30 
               
               
                   
                   
                   
                 graphite 
               
               
                 50 
                 8.59 
                 5.44 
                 Expandable 
                 650 
                 3.15 
                 4.51 
               
               
                   
                   
                   
                 graphite 
               
               
                 51 
                 10.03 
                 5.44 
                 Expandable 
                 650 
                 4.59 
                 7.41 
               
               
                   
                   
                   
                 graphite 
               
               
                 52 
                 6.91 
                 5.44 
                 LSR ONLY 
                 650 
                 1.47 
                 1.39 
               
               
                 53 
                 7.19 
                 5.44 
                 LSR ONLY 
                 650 
                 1.75 
                 3.12 
               
               
                 54 
                 7.43 
                 5.44 
                 LSR ONLY 
                 650 
                 1.99 
                 2.03 
               
               
                 55 
                 7.92 
                 5.44 
                 LSR ONLY 
                 650 
                 2.48 
                 2.73 
               
               
                 56 
                 8.36 
                 5.44 
                 LSR ONLY 
                 650 
                 2.92 
                 4.26 
               
               
                 57 
                 8.80 
                 5.44 
                 LSR ONLY 
                 650 
                 3.36 
                 3.82 
               
               
                 58 
                 9.52 
                 5.44 
                 LSR ONLY 
                 650 
                 4.08 
                 5.32 
               
               
                 59 
                 6.93 
                 5.44 
                 20% SLAG 
                 650 
                 1.49 
                 1.41 
               
               
                 60 
                 7.17 
                 5.44 
                 20% SLAG 
                 650 
                 1.73 
                 1.30 
               
               
                 61 
                 7.50 
                 5.44 
                 20% SLAG 
                 650 
                 2.06 
                 2.16 
               
               
                 62 
                 7.73 
                 5.44 
                 20% SLAG 
                 650 
                 2.29 
                 2.44 
               
               
                 63 
                 8.13 
                 5.44 
                 20% SLAG 
                 650 
                 2.69 
                 4.83 
               
               
                 64 
                 8.63 
                 5.44 
                 20% SLAG 
                 650 
                 3.19 
                 52.70 
               
               
                 65 
                 9.77 
                 5.44 
                 20% SLAG 
                 650 
                 4.33 
                 120.00 
               
               
                 66 
                 6.91 
                 5.44 
                 LSR ONLY 
                 750 
                 1.47 
                 1.42 
               
               
                 67 
                 6.77 
                 5.44 
                 SbO5 
                 750 
                 1.33 
                 1.41 
               
               
                 68 
                 7.40 
                 5.44 
                 SbO5 
                 750 
                 1.96 
                 1.30 
               
               
                 69 
                 9.19 
                 5.44 
                 SbO5 
                 750 
                 3.75 
                 2.18 
               
               
                 70 
                 10.40 
                 5.44 
                 SbO5 
                 750 
                 4.96 
                 3.12 
               
               
                 71 
                 6.47 
                 5.44 
                 Expandable 
                 750 
                 1.03 
                 1.58 
               
               
                   
                   
                   
                 graphite 
               
               
                 72 
                 6.59 
                 5.44 
                 Expandable 
                 750 
                 1.15 
                 2.26 
               
               
                   
                   
                   
                 graphite 
               
               
                 73 
                 8.73 
                 5.44 
                 Expandable 
                 750 
                 3.29 
                 4.05 
               
               
                   
                   
                   
                 graphite 
               
               
                 74 
                 9.99 
                 5.44 
                 Expandable 
                 750 
                 4.55 
                 4.50 
               
               
                   
                   
                   
                 graphite 
               
               
                 75 
                 7.19 
                 5.44 
                 LSR ONLY 
                 750 
                 1.75 
                 1.49 
               
               
                 76 
                 7.43 
                 5.44 
                 LSR ONLY 
                 750 
                 1.99 
                 1.85 
               
               
                 77 
                 7.92 
                 5.44 
                 LSR ONLY 
                 750 
                 2.48 
                 2.08 
               
               
                 78 
                 8.36 
                 5.44 
                 LSR ONLY 
                 750 
                 2.92 
                 2.27 
               
               
                 79 
                 8.80 
                 5.44 
                 LSR ONLY 
                 750 
                 3.36 
                 2.75 
               
               
                 80 
                 9.52 
                 5.44 
                 LSR ONLY 
                 750 
                 4.08 
                 4.79 
               
               
                 81 
                 6.87 
                 5.44 
                 20% SLAG 
                 750 
                 1.43 
                 1.27 
               
               
                 82 
                 7.10 
                 5.44 
                 20% SLAG 
                 750 
                 1.66 
                 1.41 
               
               
                 83 
                 7.40 
                 5.44 
                 20% SLAG 
                 750 
                 1.96 
                 2.31 
               
               
                 84 
                 7.70 
                 5.44 
                 20% SLAG 
                 750 
                 2.26 
                 1.96 
               
               
                 85 
                 8.07 
                 5.44 
                 20% SLAG 
                 750 
                 2.63 
                 2.65 
               
               
                 86 
                 8.73 
                 5.44 
                 20% SLAG 
                 750 
                 3.29 
                 15.25 
               
               
                 87 
                 9.77 
                 5.44 
                 20% SLAG 
                 750 
                 4.33 
                 83.33 
               
               
                 88 
                 9.28 
                 5.80 
                 LSR ONLY 
                 1000 
                 3.48 
                 1.88 
               
               
                 89 
                 7.00 
                 5.80 
                 20% SLAG 
                 1000 
                 1.20 
                 1.00 
               
               
                 90 
                 7.90 
                 5.80 
                 20% SLAG 
                 1000 
                 2.10 
                 1.30 
               
               
                 91 
                 8.60 
                 5.80 
                 20% SLAG 
                 1000 
                 2.80 
                 1.80 
               
               
                 92 
                 10.00 
                 5.80 
                 20% SLAG 
                 1000 
                 4.20 
                 60.00 
               
               
                   
               
             
          
         
       
     
     Some of the data in Table 1 (and  FIGS. 10-14 ) represent the average of several measurements, but are presented as one sample for simplicity. 
     Referring now to  FIG. 10 , it is clear that “20% Slag” samples provide superior performance (higher thermal resistance at a lower coating weight) to the other samples tested at 450° C. “20% Slag” samples are an embodiment of the present inventions, which are specifically 420 denier, 46×46 ends per inch, high tenacity nylon fabric coated with liquid silicon rubber that contain 20% by weight of the vitreous-slag fiber. All samples were tested using standard production airbag fabric style 3209803 fabric available from Highland Industries. Likewise,  FIG. 11  indicates superior performance of “20% Slag” samples versus other samples at 550° C. While the superior performance at 450 and 550° C. is remarkable, it was very unexpected that the coating would also impart thermal resistance at 650, 750 and 1000° C. As indicated in  FIGS. 12-14 , only the 20% slag sample provides meaningful thermal resistance time. 
     Thermal resistance at 450° C. is important because within a driver&#39;s side airbag, the sodium azide propellant upon detonation will decompose at 300° C. to produce the inflation (nitrogen) gas. Adding in an additional safety factor, 450 C is a suitable minimal operating temperature requirement, and a minimal temperature for which clinkers could develop. Thermal resistance at 650° C. and higher is important because faster deploying airbags are necessary to accommodate shorter inflation times. This necessitates the need for higher output reactions and as such higher temperature clinkers will exist. 
     Coating  58  includes between about 10% to 20% high aspect ratio additive  56  by weight, with about 20% by weight being most preferred. Used herein, “high aspect ratio” shall refer to:
         W A /H A ≧40, where W A  is the average of the longer dimension, and H A  is the average of the shorter dimension of the particles.       

     Preferably, additive  56  includes a plurality of particulates of inorganic materials, and preferably those particulates are vitreous fibers, rods, flakes, ovals or combinations of some or all of those. Preferably, particulates include silicon oxides, hydrated alumina, and metallic oxides. It is also preferred that particles of additive  56  have an average surface area of between about 0.5 and about 1.0 meters squared per gram, an average length of between about 160 and about 240 microns, and an average width of between about 1 and 20 microns. The most preferred additive  56  is PFM® Fiber  204  available from Sloss Industries Corporation of Birmingham, Ala. 
     Based on the data, it is believed that the marked improvement in burn through rate is attributable to using a high aspect ratio thermally resistant additive, such as additive  56 , as opposed to merely the thermal resistance of the additive itself. See Table 2 below: 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 THERMAL RESISTANCE AS A FUNCTION OF ASPECT RATIO 
               
             
          
           
               
                   
                   
                   
                 Specific 
                 THERMAL RESISTANCE (seconds) USING 
               
               
                 SAMPLE 
                   
                 ASPECT 
                 surface 
                 ADDITIVE IN COATING AT 3.00 OSY 
               
             
          
           
               
                 ID 
                 ADDITIVE 
                 RATIO 
                 Area (SSA) 
                 @450 C. 
                 @550 C. 
                 @650 C. 
                 @750 C. 
               
               
                   
               
             
          
           
               
                 20, 42, 64, 86  
                 PMF204 
                 40 
                 .73 
                 120 
                 120 
                 52.7 
                 15.25 
               
               
                 3, 24, 46, 69 
                 SbO5 
                 8 
                 .01 
                 120 
                 8.13 
                 3.89 
                 2.18 
               
               
                 7, 28, 50, 73 
                 Expandable 
                 1 
                 4.27 
                 120 
                 10.63 
                 4.51 
                 4.05 
               
               
                   
                 graphite 
               
               
                 13, 35, 57, 79  
                 LSR only 
                 N/A 
                 N/A 
                 120 
                 28.83 
                 3.82 
                 2.75 
               
               
                   
               
             
          
         
       
     
     As one skilled in the art would appreciate, combining an additive with a coating is a problematic endeavor considering the propensity of additive-containing formulations to become overly viscous, and therefore not be usable in a coating machine. Here, the coating viscosity problem was overcome by first splitting additive  56  between the individual components of the coating and then combining those components to make the coating. Specifically, referring to  FIG. 9 , additive ( 56 ) is combined with Component A, and additive ( 56 ) is separately combined with Component B, the Components A and B, each containing additive  56 , are combined to form coating  58 . Coating  58  is applied to base fabric web  52  to form thermal resistant material ( 50 ). 
     Preferably, the step of combining additive  56  includes the step of adding a vitreous fiber, most preferably contain silicon oxides, aluminum hydrate, and metallic oxides. Preferably, additive  56  is added to Components A and B at approximately 10% to approximately 20% by weight total. Preferably, Component A is either silicone fluid or reactant. Preferably, the step of applying coating  58  to base fabric web  52  includes the step of applying coating  58  whose viscosity is between approximately 15,000 and 70,000 centipoises. Preferably, base fabric web  52  is nylon, polyester, acrylic, or combinations including some or all of those, with high tenacity nylon 66 being the most preferred. Preferably, 4 ounces of coating  58  are applied per square yard of base fabric web  52 . Preferably, the step of applying coating includes the step of applying a polymeric silicone elastomer, with room temperature vulcanizing polymeric silicone elastomer being most preferred. Coating can be accomplished by blade coating, knife over air coating, slot die coating, knife over belt coating, reverse roll coating or another method known in the art. 
     Samples set forth in this application contain the following components (ingredients), obtained from the following sources: 
     
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 COMPONENTS AND SOURCES 
               
             
          
           
               
                   
                   
                 MANUFACTURER&#39;S 
                   
               
               
                   
                 COMPONENT 
                 DESIGNATION 
                 SOURCE 
               
               
                   
                   
               
               
                   
                 Fabric 
                 3209803 
                 Highland Industries 
               
               
                   
                 LSR 
                 X832-394 
                 Shin Etsu 
               
               
                   
                 Slag 
                 PMF 204 
                 Sloss Industries 
               
               
                   
                 SbO5 
                 Burnex A1582 
                 Nyacol Nano 
               
               
                   
                   
                   
                 Technologies 
               
               
                   
                 Expandable 
                 Nyagraph 35S 
                 Nyacol Nano 
               
               
                   
                 Graphite 
                   
                 Technologies 
               
               
                   
                   
               
             
          
         
       
     
     In use, thermal resistant material  50  is formed by coating base fabric web  52  with coating  58  including additive  56 . The thermal resistant material  50  is then formed into heat shield  30 , and attachment plates  34  with fasteners  36  are connected. Heat shield  30  is placed within air bag  20  so inlets  42  of heat shield  30  and airbag  20  are aligned, then fasteners  36  of attachment plates  34  are put through shield fastener openings  32  and bag fastener openings  22 , and then secured with, for example, a conventional nut. Inflator  15  is connected to inlet  42 , and the airbag/heat shield/attachment plate/inflator assembly is put behind cover  12 . 
     The relationship between aspect ratio of the additive and thermal resistivity was not expected. Rather, it was expected that the thermal properties alone of the additive would control the burn-through rate of the resulting coating and that the physical properties of the additive would have little effect or interaction with the thermal properties of the additive. 
     It was also unexpected that slag would be a suitable additive in a textile coating given slag&#39;s sand-like physical properties, which would be expected to create an abrasive product and likely erode durability of the end product. 
     Another unexpected result of the present inventions is that it is even possible to combine the additive in such a high concentration amount without creating an undesirably viscous coating. Specifically, the effect of combining particulates with a liquid is well known to increase viscosity, and those skilled in the art know that overly viscous coatings do not lend themselves to use in standard equipment and applications. 
     Yet another unexpected result was that long thin rods would be amenable to use in a coating given their affinity for a birefringent orientation in standard coating machines, which would be expected to make uniform distribution difficult to achieve. 
     However, in spite of the aforementioned hurdles, the present inventions were able to employ nonconventional components with particular characteristics while, at the same time, overcome the viscosity problems to formulate a coating with exceptionally good thermal resistance times. 
     Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. By way of example, thermal resistant material  50  may be used to form both airbag  20  and heat shield  30 . Also, thermal resistant material  50  could be used in a variety of other items, including personal thermal protection garments. Moreover, items like, welding blankets, spatter shields, fires sleeves, automotive firewall, wildland fire shelter, turnout gear, cargo covers, structurally reinforced and thermally resistant thermoplastic coatings, could be manufactured in similar detail. Additionally, higher levels of protection can be achieved through coating both the face and back of a substrate. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.