Multi-shot injection molded method and product

A reinforcing structure comprising:

• (a) a carrier formed by pultrusion and having a predetermined shape prior to installation and adapted to fit in a cavity of a vehicle, the carrier including:
• (i) at least one portion with a longitudinal axis and having an outer surface with a first end and a second end, and (ii) a plurality of ribs having a width of from about 0.1 mm to about 5 mm;
• (b) a first expandable material, which is epoxy-based and capable of being activated to expand under a first activation condition, come into contact with, and adhere to a wall defining the cavity in order to at least partially fill the cavity;
• wherein the first expandable material is capable of expanding from about 25% to about 400% as compared to its green state;
• and
• (c) a second expandable material, which is an acoustic material that is ethylene-based and capable of being activated to expand under a second activation condition, to come into contact with, and adhere to a wall defining the cavity in order to at least partially fill the cavity, the second expandable material being capable of expanding from about 200% to about 5000% as compared to its green state;
• wherein the first expandable material, the second expandable material, or a combination thereof, alone, or in combination with the carrier expands to form a complete seal of the cavity following activation;
• and
• wherein the carrier is comprised of a first carrier layer and a second carrier layer, the second carrier layer being a fiber reinforcement.