Patent ID: 7011315

Claim:
An expandable, pre-formed plug suitable for sealing or structurally reinforcing surfaces defining a space therebetween, said plug comprising: an expandable core including a blowing agent, and being provided in an initial unexpanded state adapted, upon activation, for expanding to at least 1000% the volume of the unexpanded core in the initial unexpanded state; and an outer skin that is about 1% to about 30% by weight of the plug, and that has been mono-sandwich injection molded about the core while the core is in its initial unexpanded state, the outer skin being generally dry to the touch and including an adhesion-promoting material; wherein, upon application of an external stimulus, the core expands to at least 1000% of the volume of the unexpanded core in the initial unexpanded state and facilitates the displacement of the outer skin in a coordinated manner until at least a portion of the outer skin contacts a portion of the surfaces defining the space.