Page 84 - Handbook of Adhesion Promoters

5

Typical Primer Formulations

and Applications to

Different Substrates

A primer is a chemical composition used as a preparatory coat which is applied on any
substrate to increase adhesion, prevent excessive penetration of substrate by coating, or
smooth a surface of the substrate. Many products require the application of primer to
increase adhesion or to improve adhesive properties of products performing under harsh
conditions. The following groups of products frequently use primers: adhesives and seal-
ants, coatings, coil coatings, cosmetics, dental materials, leather, metals, optical materials,
paper, polymers and plastics, printing inks, and wood. A selection of proposed formula-
tions for these groups of products is presented below to illustrate typical compositions,
differences in various applications, and the range of raw materials involved.

5.1 ADHESIVES AND SEALANTS
Water-based primer for polyurethane sealant 1
5.09 parts isopropyl-tri(N-ethylenediamino)ethyltitanate
1.33 parts γ-glycidoxypropyltrimethoxysilane
1.01 parts γ-glycidoxypropylmethyldiethoxysilane
92.57 parts water

Primer for pressure-sensitive acrylic foam tape 2
10 wt% polyamide (Macromelt 6238)
45 wt% isopropyl alcohol
45 wt% toluene

Primer for polyurethane sealants 3
3.99 wt% acrylic resin (Paraloid A-21)
3.99 wt% polyester resin (Vitel 2300 BU)
13.63 wt% methylene diphenyl isocyanate (PAPI 2020)
6.15 wt% tris(p-isocyanatophenyl)-thiophosphate (Desmodur RFE)
0.30 wt% catalyst (Dabco T-30)