Melt-processable adhesives for bonding pervious fluoropolymeric layers in multilayer composites

A multilayer composite, comprising:

• a.) a first layer comprising pervious fluoropolymer selected from the group consisting of fluoroelastomeric thermoplastic vulcanizate, etched polytetrafluoroethylene, and combinations thereof;
• and
• b.) a second layer melt-bonded to the first layer, the second layer comprising homogenous fluoropolymer selected from the group consisting of fluoroelastomer, fluoroplastic, and combinations thereof;
• c.) wherein the homogenous fluoropolymer of the second layer is compositionally different from the pervious fluoropolymer of the first layer;
• and
• d.) the etched polytetrafluoroethylene of the first layer is derived from polytetrafluoroethylene in a first layer precursor component etched such that etched polytetrafluoroethylene in the precursor component has a carbon to fluorine weight ratio from about 0.35 to about 10.

A precured multilayer composite, comprising:

• a.) a first layer comprising pervious fluoropolymer selected from the group consisting of fluoroelastomeric thermoplastic, polytetrafluoroethylene etched such that etched polytetrafluoroethylene in the first layer has a carbon to fluorine weight ratio from about 0.35 to about 10, and combinations thereof;
• and
• b.) a second layer comprising a homogenous fluoropolymer selected from the group consisting of fluoroplastic, uncured fluoroelastomer, and combinations thereof;
• c.) wherein the uncured fluoroelastomer is liquid at room temperature and the homogenous fluoropolymer has
• i.) fluorinated molecules derived from at least one monomer unit stoichiometrically identical to a monomer unit of the fluorinated molecules of the pervious fluoropolymer,
• ii.) a liquefaction range supra-point temperature not greater than the liquefaction range supra-point temperature of the pervious fluoropolymer,
• iii.) a liquefaction range supra-point temperature not less than the liquefaction range sub-point temperature of the pervious fluoropolymer, and
• iv.) a viscosity at the liquefaction range supra-point temperature of the homogenous fluoropolymer that is less than the viscosity of the pervious fluoropolymer at the liquefaction range supra-point temperature of the pervious fluoropolymer.