Energy savings plus mechanical reinforcement and rheology control

2K Polyurethane Insulating Glass Sealant

Adhesives Formulation

Applicable Type

Reactive Adhesives

Applicable Base Polymer

Polyurethanes

Applicable Industrial Sectors

Buildings & constructions

Applicable Base Polymer Properties

Polyurethanes are extensively and successfully used as adhesives and sealants, and they have an excellent record of durability. Polyurethane-based adhesives form tough bonds with high peel strength. They have better low temperature strength than other adhesives. They have exceptionally high strength at cryogenic temperatures. They have good chemical resistance, although not generally as good as epoxies or acrylics. Urethanes do not have high temperature resistance. Maximum upper use limits are about 150°C, and most formulations are used below 100°C.

Typical Formulation Ingredients

Ingredient

Parts by weight

Part A:

Polybutadiene polyol (Liquiflex H, Petroflex)

xxxxxx

Plasticizer (Santicizer 261, Ferro)

xxxxx

Tackifier (Abitol, Eastman Chemical)

xxx

Catalyst (Thorcat 535, Thor)

xxx

Thickener (Lorol C-18, BASF)

xxx

Precipitated calcium carbonate (Calofort S, Mineral Technologies)

xxxxx

Calcium carbonate drying agent (Eskal 430, Glasstec)

xxxxx

Molecular sieve (Purmol, Zettachem)

xxx

Part B:

Isocyanate (M143L, Dow Chemical)

xxxxx

Plasticizer (Santicizer 261, Ferro)

xxxxx

Carbon black masterbatch

xxxxx

p-toluenesulfonyl isocyanate

xxx

Silane (A-187, Momentive)

xxxx

Fumed silica (Aerosil R972, Evonik)

xxxx

(Source: Amstock, J.S., Handbook of Adhesives and Sealants In Construction, McGraw-Hill, New York, 2000, p. 12.12)

Typical Properties

Properties

Mixing ratio (Part A:Part B) by weight

xxx

Working life, mins

xxxxx

Tack-free time, hrs

xxx

Sag, in

xxxx

Tensile strength, psi

xxx

Tear strength, pli

Elongation, %

xxx

Hardness, Shore A

100% Modulus, psi

xxx

Water vapor transmission, g/m2/24hr

xxxx

Lap shear glass-to-glass, psi

xxxx

Processing

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.

Tips and Tricks

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