Лако-красочные материалы — производство

Flexible and nonwarp glues are compounded animal glue-based products available in cake or dry blend form. Flexible cake glues are formulated to provide a permanent, flexible, resilient film. Glycerine is normally the primary plasticizer and may be modified with sorbitol and other glycols. Higher grades of animal glue are normally used to provide film strength and resiliency. The ratio of plasticizer to dry glue controls the film flexibility, and can be varied from a moderate degree of flexibility to a fully flexible film. These products are used in such applications as bookbinding, including hardcover books, direc­tories, and catalogs, notebook binders, and soft-sided luggage.

Nonwarp cake glues are designed to provide a ‘‘lay flat’’ or nonwarp film with little or no curling upon drying. The nonwarp property is obtained through the use of various sugars and corn syrup. Tack and speed of set can be varied by choice of glue grade and ratio of dry glue to the sugars and other modifiers. Glues supplied in cake form have the advantage of ease of melting and minimal water dilution by the user (normally up to 20%). Dry blends are basically simple, nonwarp formulations supplied by the manufac­turer in dry, fine mesh form, which the customer dissolves in hot water prior to use. These products have indefinite shelf life and lower shipping cost because of the absence of water.

Major areas of use for nonwarp glues are for set up boxes, casemaking for book covers, hard notebook binders, slipcases, looseleaf computer manuals, record covers, hard luggage, caskets, and laminating. Because of differences in equipment, application, and end-use requirements, compounded glues are formulated for each use and/or customer, and may be further modified to compensate for seasonal changes in humidity and tem­perature. Speed of set, for example, can vary from almost instantaneous to over 5 min. Properties of importance include viscosity at the recommended operating temperature, degree of tack and speed of set, and final bond characteristics.