Page 503 - Handbook of Adhesives and Sealants

Selection of Adhesives 435

more difficult to bond. However, recently developed adhesive primers
improve the bond of these elastomers to metal substrates. Surface
treatment of the substrate before priming should be according to good
standards. Figure 11.2 illustrates a bondability index of common elas-
tomers and plastics.

11.4.4 Adhesive bonding of other common
substrates
11.4.4.1 Wood. Wood adhesives are probably the oldest adhesives
known to man. Adhesives used for wood include animal or hide glues,
starch, casein, soybean, blood glues, and fish glues as well as modern
synthetic resins.
Resorcinol and resorcinol-formaldehyde resins are cold setting
adhesives for wood structures. They have been shown to be at least
as durable as wood itself under all conditions. Urea-formaldehyde
adhesives, commonly modified with melamine formaldehyde, are
less durable. They are used in the production of plywood and in
wood veneering for interior applications. Phenol-formaldehyde and
resorcinol-formaldehyde adhesive systems have the best heat and
weather resistance. Polyvinyl acetates are quick drying, water based
4
adhesives commonly used for the assembly of furniture. This adhesive

Figure 11.2 Bondability index for plastics and elastomers; 10 best; 1 worst.