Abstract: Thread locking compositions and analogous sealant materials having limited cured strength, and a preferred method for their compounding and application, are disclosed. These are based primarily on alpha cyanoacrylates, i.e. acrylate esters in monomer or low polymeric form, or of very low molecular weight, which are rapidly polymerizable to form solid and bonding films. The materials, in liquid form, are modified by inclusion of coloring agents and other film strength and reaction rate modifiers, to impart optimum properties of bonding strength, curing rate, moderate resistance in torque to separation of the bonded parts, low residual torque, along with good stability in storage, or good shelf life. Combinations of polymerization promoters and stabilizers are included, along with small quantities of specially selected coloring agents which not only impart effective color to thin films of the composition but serve to limit curing below high cured strength.
Type:
Grant
Filed:
July 16, 1979
Date of Patent:
October 27, 1981
Assignees:
Pacer Technology and Resources, Inc., Sumitomo Chemical Company, Ltd.
Inventors:
Senji Kusayama, Eijiro Nishi, Hugh J. Stock
Abstract: Adhesive bonds between materials, such as woods having porous surfaces, formed by polymerizing in situ alphacyanoacrylate monomers, are accelerated in curing and strengthened by precoating the surfaces to be joined with a solid mixture of alkaline or basic accelerator, such as sodium or potassium hydroxide or sodium borosilicate spheres of micro-size, combined in a chalkable calcareous binder to form a light but adhesive permeable coating, before the monomeric adhesive is applied. The latter permeates in part through the light precoating to bond into the wood and is accelerated in its polymerization so that it is not excessively absorbed into the porous substrate, resulting in a bond of superior strength.