Hot Melt Adhesive

The hot melt was prepared by a typical prepolymer procedure. A higher reaction temperature of between 90-100C can be used. The final melt is poured into containers and kept under a nitrogen blanket at room temperature.
For testing the hot melt adhesive is molten at 90C and applied to one side of the substrate. The substrate is then reheated and the second substrate under minimal pressure. The system is cured at 90C for 1 hour.
The mechanical properties of the adhesive will decrease if polyether with a higher degree of unsaturation are used. It is possible to improve the mechanical properties of such polyols by using a small amount of a tri-functional polyol or with diethanolamine.
Formulation Hot Melt Adhesive using a low unsaturation Polyether diol

Polyether propylene oxide, ethylene oxide capped, MW 2500 OH # 49 low unsaturation (CAS # 9003-11-6)

50 35
Propylene glycol MW 400 OH # 280  (CAS # 25322-69-4) 50 50
Polyester MW 2000 15
1,4-butanediol (CAS # 110-63-4) 1 1
4,4-MDI purified NCO % 33   (CAS #  101-68-8) 43 43
Isocyanate index NCO/OH 1.15 1.15
Isocyanate, % 1.3 1.3

Hard segments, %

30 30
Wood to Wood tensile adhesion, ASTM D897, PSI (kPa) 85(585) 90(620)
Leather Peel Strength, ASTM D1876, PSI  (kPa) 20(138) 15(103)
Vinyl Peel Strength, ASTM D1876, PSI  (kPa) 5(34) 16(110)

Last edited on:

November 16, 2006

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