Лако-красочные материалы — производство

Animal glues were the traditional adhesives for woodworking, finding acceptance for edge gluing, assembly, veneering, inlays, and finishing. They have been largely supplanted by ready-to-use, synthetic, water-based emulsion adhesives, and to a smaller degree by hot melts for some applications. Animal glues are still used in high-quality furniture and for critical applications such as pianos.

Edge gluing includes the joining of wood pieces for table and desk tops, chair bottoms, core stock construction, and posts and blocks for turning. Assembly gluing is the putting together of panels and parts in cases, cabinets, chairs, and drawer construction. For high-speed edge gluing, assembly gluing, post lamination, and operations with short assembly times, medium to higher testing grades are used. Low to medium grades are usually preferred for slower-speed assemblies, veneering, and edge banding operations. For medium to high test grades, water/glue ratios vary from 11 to 14:1 for rapid assembly times in the range 0 to 15s closed time, to 2 to 2^:1 for slow assembly times in the range of 1 min closed time until pressure is applied. For low to medium grades, water/glue ratios vary from 18 to 13:1 for rapid times to 1| to1|:1 for slow times.

In edge and assembly gluing, a thin uniform coat of glue is applied to the surface to be bonded. The surfaces are lined up, joined, and then clamped under adequate pressure (in the range 100 to 150 psi). The pieces are then removed for final air drying until the full strength of the bond is developed. Animal glues possess high tensile strength—greater than that of the wood—in addition to their tack and set properties. Also, the film does not creep. Liquid animal glues, usually 50 to 60% solids, find application in panel or frame assembly of hard board to wood for cabinets, drawer assembly, corner blocking, trailer assemblies, and other applications where a ready-to-use adhesive with a relatively long open time is desired.

As less commonly known use of animal glues is as a size for the finishing of high — quality furniture surfaces. In this procedure, a dilute, warm glue solution is applied to the surface of the wood and is allowed to dry. The compression grain of the wood is raised and the glue fills the exposed, porous wood surface. On sanding, a glasslike surface is obtained which takes a uniform, lasting stain at reduced levels of finish.