Abstract:
Fault-responsive indicator beads ( 10 ) are provided for integration into the system of a substrate such as a coating structure, a vehicle, a garment, or a package part. Each bead ( 10 ) comprises a shell ( 11 ) designed to fracture when the system encounters a fault condition. A core ( 12 ), within the shell ( 11 ), contains a material which is dormant when the shell ( 11 ) is intact and functional when the shell ( 11 ) is fractured.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority under 35 USC §119(e) to U.S. Provisional Patent Application No. 61/591,256 filed on Jan. 26, 2012. The entire disclosure of this provisional patent application is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Structures, vehicles, garments, packaging, and other substrates are often vulnerable to integrity-compromising conditions. These conditions can be caused by, for example, unexpected impact, internal or external pressure, deliberate tampering, unacceptable temperature, stress, strain, dislocation, deformation, and/or distortion. 
       SUMMARY 
       [0003]    A fault-responsive bead is provided which contains a material that is dormant in pre-fault condition and functional in a post-fault condition. The material can be an indicator signifying that a fault has occurred and/or the material can be a remedy helping to mitigate the consequences of the fault. 
     
    
     
       DRAWINGS 
         [0004]      FIGS. 1A-1B  each show a fault-responsive bead. 
           [0005]      FIGS. 2A-2B ,  FIGS. 3A-3B , and  FIGS. 4A-4B  each show a substrate incorporating a plurality of the fault-responsive beads. 
       
    
    
     DESCRIPTION 
       [0006]    Referring now to the drawings, and initially to  FIGS. 1A-1B , a fault-responsive bead  10  comprises an exterior shell  11  and an interior core  12 . When the shell  11  is intact, the core  12  is completely enclosed and, when the shell  11  is fractured, the core  12  is exposed. The fault-responsive bead  10  can be made by encasing a core-forming droplet in a heated polymer which when cooled forms the shell  11 . 
         [0007]    Referring now to  FIGS. 2A-2B , the fault-responsive beads  10  are shown integrated into a substrate  20 . The substrate  20  can comprise, for example, a structure (e.g., pipelines, process equipment, storage tanks, cables, etc.), a vehicle (e.g., aircraft, watercraft, trains, automobiles,) a garment (e.g., sterilization suits, protective gloves, etc.), and/or a package part (e.g., containers, labels, tapes, etc.). In  FIG. 2A , the substrate  20  is shown in an intact condition wherein the beads&#39; shells  11  are intact and the core  12  is completely enclosed. In the post-fault condition shown in  FIG. 2B , the shells  11  in the affected region are fractured to expose the core  12 . 
         [0008]    As shown in  FIGS. 3A-3B , the fault-responsive beads  10  can be integrated into the substrate  20  via incorporation directly into the main substrate body  30 . In this case, for example, the beads  10  can be dispersed within the substrate-making material during initial formation. 
         [0009]    As shown in  FIGS. 4A-4B , the fault-responsive beads  10  can be integrated into the substrate  20  via a coating layer  40  situated on the main substrate body  30 . In this case, for example, the beads  10  can be dispersed within a coating fluid and/or resin  41  which is applied to a surface of the substrate body  30 . 
         [0010]    In the illustrated embodiments, the bead  10 , the shell  11 , and the core  12  are all substantially spherical in shape. The shell&#39;s diameter D11 defines the bead&#39;s diameter D10, and the shell&#39;s thickness T11 is defined by the difference between its diameter D11 and that core&#39;s diameter D12. 
         [0011]    The beads  10 , the shells  11 , and/or the cores  12  can be any suitable size to optimize performance and fault-indicating purposes. Larger diameters (e.g., 1 to 8 mm) may be best suited when the beads  10  are incorporated into the substrate body  30 . Smaller bead sizes (e.g., 1 to 100 microns) may be best suited when the beads  10  reside in a thin film coating layer  40 . And intermediate bead sizes (e.g., 100 microns to 3 mm) might be the best candidates when the beads  10  are occupants of a thick adhesive or paste coating. 
         [0012]    The shell&#39;s thickness T11 (i.e., the difference between its diameter D11 and the core diameter D12) and/or the shell material composition can be tailored to provide the appropriate rupture trigger, fracture mechanism, and/or fracture strength. 
         [0013]    The beads&#39; shells  11  can also be adapted to be essentially unnoticeable in the pre-fault condition. Specifically, for example, the shells  40  can be an opaque color blending with the color of the substrate body  30  (if incorporated therein) or the coating layer  40  if incorporated therein. Thermoplastic and/or thermoset resins (e.g., poly oxy methylene urea (pmu), urea formaldehyde, phenolic, epoxy, polyester, polyethylene, polypropylene, polyamide, etc.) can be considered suitable candidates for shell materials. 
         [0014]    The core  12  can comprise an indicating material such as a pigment mixture adapted to be incompatible (e.g., insoluble) with the surrounding medium so as to flow in a fault-indicating manner. The pigment color can be contrasting with that of the substrate body  30  and/or the coating fluid  41 . Additionally or alternatively, the indicator  12  can be activated and/or detected by heat, light, radiation, infrared, electrical fields, orientation, oxidation or other effect mechanisms. 
         [0015]    The indicator core  12  could instead comprise a substance such as reactive chemicals, charged or conductive particles, metallic particles, charge-inhibiting particles, thermochromic pigments, or other marker materials. 
         [0016]    The indicator core  12  can additionally or alternatively include a remedial substance (e.g., a self-sealing resin, disinfectant, neutralizing agent, chemical additive, etc.). 
         [0017]    Although the beads  10 , the substrate  20 , the substrate body  30 , and/or the coating layer  40 , have been have been shown and described as having certain forms and fabrications, such portrayals are not quintessential and represent only some of the possible adaptations of the claimed characteristics. Other obvious, equivalent, and/or otherwise akin embodiments could instead be created using the same or analogous attributes.