Лако-красочные материалы — производство

Adhesives derived from cellulose are used in a wide variety of applications that require an economical means for bonding porous substrates. Specific uses and formulations of var­ious cellulose ester and ether adhesives are discussed in the following sections. 1. Cellulose Nitrate Cellulose nitrates with DS values of 1.8-2.3 are used in plastics, lacquers, coatings, and […]

Cellulose ethers are prepared by replacing the hydrogen on the cellulose hydroxyl groups with an alkyl group. The substitution reaction first involves the removal of the hydrogen by sodium hydroxide to make sodium cellulose (Fig. 2d). The sodium cellulose is then reacted with the appropriate alkyl halide or epoxide. Reaction with an alkyl halide yields […]

Esterification of cellulose to give cellulose trinitrate was discovered by Schonbein in 1846 using a mixture of sulfuric and nitric acids. The resultant compound was so flammable that its first use was as smokeless gunpowder. By the end of the ninteenth century, cellulose nitrates had been prepared with a lower DS, and they could safely […]

Each glucose unit in a molecule of cellulose has three hydroxyl groups that can be used to derivatize the cellulose by reactions common to all alcohols. It is uncommon, and for some derivatives impossible, to achieve a degree of substitution (DS) of three. Most important derivatives of cellulose have a DS that is somewhat below […]

Cellulose is the principal structural material in the cell wall of all plants and is also found in algae, bacteria, and animals (tunicates). Approximately 1011 tons of cellulose is formed each year; this puts cellulose among the most important renewable resources in the world [1]. A. Cellulose Structure Cellulose is a homopolymer of р-D-anhydroglucopyranose monomeric […]

Melissa G. D. Baumann and Anthony H. Conner Forest Products Laboratory, USDA-Forest Service, Madison, Wisconsin, U. S.A. I. INTRODUCTION Carbohydrates in the form of polysaccharides are readily available from all plants, the exoskeletons of various marine animals, and some microorganisms. Because up to three — fourth of the dry weight of plants consists of polysaccharides, […]

Animal glues are used in leather manufacturing as a component of fat liquoring com­pounds which are used to impart softness to the leather, and as a filling agent to give added body to the leather. They are also used in finishing. Low-grade animal glues are employed as a component with whiting, linseed oil, and rosin […]

An unusual application for animal glues is in glass chipping, recently the subject of revived interest. Chipped glass is used for decorative panels in such items as doors, windows, and lampshades. The frost or fernlike design is produced by pouring an animal glue solution of about 30 to 35% solids on a clean, sandblasted glass […]

Animal glue-impregnated gasket materials are used as seals between two joined surfaces. They are water, oil, and solvent resistant, flexible, compressible, economical, and do not bond to the sealed surface. In the production of fiber or paper gaskets, the saturating procedure is carried out by drawing the fiber or paper stock through a shallow tank […]

Animal glues are used in rubber compounding to modify the physical properties of the rubber. In particular applications such as textile rollers, cots, and aprons used in weaving cloth, the glue prevents static buildup during weaving, which causes fiber lapping or winding of fibers around rollers. The static electricity is discharged through the rollers, due […]