Selectively applied adhesive particulate on nonmetallic substrates
The manufacturing of articles relies on the bonding of two or more components to form some forms of the articles, such as a shoe sole bonded with a shoe upper. The bonding may be achieved with an adhesive particulate that is applied to a surface of a substrate. The adhesive particulate is selectively fused to the substrate with a controlled energy source, such as a laser. The selective application of laser energy allows for specific geometric structures of adhesive particulate to be formed on the substrate. The substrate having the fused adhesive particulate is mated with another component allowing the fused adhesive particulate to bond the first substrate and the second component.
1. A method of applying an adhesive particulate to a nonmetallic substrate, wherein the substrate is a sole portion of an article of footwear, the method comprising:
applying an adhesive particulate to a portion of the substrate;
selectively applying laser energy to the applied adhesive particulate and the substrate at a foot-facing surface to fuse the adhesive particulate and the substrate selectively, forming a fused adhesive particulate portion, wherein selectively applying laser energy comprises:
applying laser energy that is sufficient to form the fused adhesive particulate portion at a first location, and
applying laser energy that is insufficient to form the fused adhesive particulate portion at a second location;
after selectively applying the laser energy, removing an unfused portion of the applied adhesive particulate from the substrate; and
subsequent to removing the unfused portion of the applied adhesive particulate, applying thermal energy to the fused adhesive particulate for bonding the substrate with a second substrate.
2. The method of claim 1 , wherein prior to applying the adhesive particulate, applying a primer to the substrate.
3. The method of claim 1 , wherein applying the adhesive particulate uses an electrostatic applicator that electrostatically charges the adhesive particulate.
4. The method of claim 3 , wherein a conducting agent is not applied to the substrate to achieve an electrostatic application of the adhesive particulate.
5. The method of claim 1 , wherein the adhesive particulate is comprised of a powdered adhesive.
6. The method of claim 5 , wherein the powdered adhesive is comprised of at least one selected from the following:
a thermoplastic polyurethane (“TPU”);
ethylene vinyl acetate (“EVA”); and
polyolefins.
7. The method of claim 1 , wherein a melting point of the adhesive particulate is within the range of 50 degrees Celsius to 130 degrees Celsius.
8. The method of claim 1 , wherein the adhesive particulate is comprised of an infrared doping agent.
9. The method of claim 1 , wherein selectively applying the laser energy comprises applying the laser energy to a first portion of the adhesive particulate in a location relative to the substrate where an adhesive is desired and not applying the laser energy to a second portion of the adhesive particulate in a location relative to the substrate where an adhesive is not desired.
10. The method of claim 1 , wherein selectively applying the laser energy comprises varying a positive level of energy applied from a laser at a first location of the substrate relative to a second location of the substrate.
11. The method of claim 1 , wherein selectively applying the laser energy further comprises directing the laser energy at the first location of the substrate and intentionally avoiding application of laser energy at a third location of the substrate.
12. The method of claim 1 , wherein the selectively applying laser energy produces a fused adhesive particulate perimeter enclosing a non-fused adhesive particulate area.
13. The method of claim 1 , wherein the laser energy is produced by a diode laser in at least the near infrared spectrum range.
14. The method of claim 1 , wherein subsequent to removing the unfused adhesive particulate, applying a crosslinking material to the fused adhesive particulate.
15. The method of claim 14 , wherein the crosslinking material is an encapsulated isocyanate hardener.
16. The method of claim 14 , wherein the applying the crosslinking material is comprised of applying the crosslinking material as a water-based dispersion.
17. The method of claim 14 , wherein the application of thermal energy elevates the fused adhesive particulate having the crosslinking material to a temperature range between 60 degrees Celsius and 80 degrees Celsius.
18. The method of claim 1 , wherein the application of thermal energy is, at least in part:
produced from an infrared energy source; or
conducted through the substrate to the fused adhesive particulate.
19. The method of claim 1 , wherein subsequent to applying thermal energy to the fused adhesive particulate, bonding an article of footwear component with the second substrate.
20. The method of claim 19 , wherein the second substrate is comprised of a fused adhesive particulate portion.
21. The method of claim 1 , wherein the substrate is a component for use in an article of footwear.