Epoxy adhesives often come in a two-part arrangement, typically a resin and a hardener. Loctite has a product suited for a vinyl fence called Plastics Bonding System, which sells on Amazon for $27.38.

Vicpricme epoxy glue: is a clear two part epoxy glue in a 1.76fl.oz syringe package that cures quickly and provides a strong and long lasting bond on metal, wood, most plastics, rubber ...

Plasticbonder: Is A Quick-Set, 2 Part, Urethane Adhesive System That ... Versatile And Dependable: Perfect For Indoor Or Outdoor Use, Epoxy & Adhesives, Plastic, Composite, Pvc, And More.