Typical Formulation Ingredients
Phase
Ingredient
Parts by weight
A
Polybutadiene resin (Poly bd R45HTLO, Cray Valley)
A
Chain extender (2-ethyl-1,3-hexanediol)
A
Asphalt (120-150 penetration)
A
Filler (calcium carbonate)
A
Molecular sieve (Siliporite SA1720, Atofina)
A
Process oil (naphthenic or phthalate based)
B
Polyfunctional MDI liquid
Typical Properties
Viscosity of Part A @ 55° C
Viscosity of Part A @ 85° C
Tensile strength of adhesive film, psi
Elongation of adhesive film, %
Tear (ASTM D1004 Die C), pli
Resulting Properties
The formulation above is for a general purpose two component polyurethane adhesive based on polybutadiene polyol. Using polybutadiene polyol will provide much better hydrolytic stability than other conventional polyols (e.g., polyester or polyether).
Often additives are not required to provide flexibility or toughness as in the case of epoxy formulations. Polyurethanes have the capability of providing these properties through manipulation of the resulting molecule by proper choice of isocyanate and polyol. However, additives are used mainly to stabilize the adhesive relative to moisture, oxidation, UV, etc.
The source of Polybutadiene Polyol Based Polyurethane Sealant formulation is Cray Valley.