Cellulose acetate is also known as cellulose acetic ester. In the presence of a sulfuric acid catalyst, cellulose is acetylated with a mixture of acetic acid and ethanol, and then hydrolyzed with dilute acetic acid to the desired degree of esterification. Cellulose acetate can be used to prepare solvent - based adhesives for bonding plastic products such as glasses and toys. Compared with nitrocellulose, it has excellent tack resistance and durability, but is inferior in acid resistance, moisture resistance, and weather resistance.

Protein Adhesives
Protein adhesives are a type of natural adhesives that use protein - containing substances as the main raw materials. Both animal proteins and plant proteins can be used to make adhesives. According to the proteins used, they are divided into animal proteins (hide glue, gelatin, casein glue, albumin) and plant proteins (such as soybean glue). Generally, they have high bonding strength when dry and are used in furniture manufacturing and wood product production. However, their heat resistance and water resistance are poor, among which animal protein adhesives are more important.

Soybean Protein Adhesives
Plant proteins are not only important food raw materials but also have a wide range of applications in non - food fields. Regarding soybean protein adhesives, as early as 1923, Johnson applied for a patent for soybean protein adhesives. In 1930, the soybean protein - phenolic resin wood board adhesive (DuPont) was developed. Due to its weak bonding strength and high production cost, it could not be used in large quantities. In recent decades, due to the expansion of the adhesive market, the limited nature of global petroleum resources, and increasing concerns about acid pollution and environmental problems, the adhesive industry has re - considered new types of natural adhesives, making soybean protein adhesives a research hotspot again. Soybean adhesives are non - toxic, odorless, and easy to use, but have poor water resistance. Adding 0.1% - 1.0% (by mass) of cross - linkers such as thiourea, carbon disulfide, and tricarbomethylsulfide can improve water resistance, and the resulting adhesives can be used for wood bonding and the production of plywood.

Animal Protein Adhesives
Animal glues have been widely used in the furniture and wood processing industries. Common products include furniture such as chairs, tables, and cabinets, models, toys, sports equipment, and laminates. The relatively new liquid animal glues with a solid content of 50% - 60% include fast - curing and slow - curing types. They are used in the bonding of frame boards of cabinet hardboards, mobile home assembly, difficult - to - laminate materials, and other small - and medium - sized adhesive - demanding occasions where it is not suitable to use cheaper hot animal glue solutions.
Animal glue is a basic type of adhesive used in adhesive tapes. These tapes can be used for common light - duty retail packaging bags as well as heavy - duty tapes, such as the sealing or encapsulation of solid - fiber and corrugated cartons for shipping goods. In such cases, rapid mechanical operation and long - lasting high bonding strength are required. At this time, a large amount of bone glue is used, and hide glue is often used alone or in combination with bone glue. The adhesives used are generally formulated to have a solid content of about 50%, and 10% - 20% of dextrin (by the mass of dry glue) can be blended, along with a small amount of wetting agents, plasticizers, and gel inhibitors (if necessary). The adhesive (at 60 - 63 °C) is usually coated on the backing paper with a coating mixture, and the solid deposition amount is generally 25% of the mass of the paper base. The wet tape can be dried with a steam - heated roller under tension or with a direct heater with adjustable air.
In addition, the applications of animal glue also include the manufacture of sandpaper and abrasive cloth, the sizing and coating of textiles and paper, and the binding of books and magazines.

Tannin Adhesives
Tannin is an organic compound containing multiple phenolic groups and is widely present in the stems, barks, roots, leaves, and fruits of plants. It mainly comes from the bark waste in wood processing and plants with high tannin content. By mixing tannin, formaldehyde, and water, heating to obtain tannin resin, and then adding a curing agent and filler and stirring evenly, tannin adhesive is obtained. Tannin adhesive has good resistance to heat - humidity aging, and its wood - bonding performance is similar to that of phenolic adhesives. It is mainly used for bonding wood and other materials.

Lignin Adhesives
Lignin is one of the main components of wood, accounting for about 20 - 40% of the wood, second only to cellulose. Lignin is difficult to extract directly from wood, and its main source is pulp waste liquid, with extremely rich resources. Lignin is not used alone as an adhesive. Instead, phenolic resin - like polymers obtained by the reaction of the phenolic groups of lignin with formaldehyde are used as adhesives. To improve water resistance, it can be used in combination with compounds such as cycloalkyl isocyanate, phenol, and resorcinol. Lignin adhesives are mainly used for bonding plywood and particleboard. However, they have high viscosity and a deep color. After improvement, their application scope can be expanded.

Gum Arabic Adhesives
Gum Arabic, also known as acacia gum, is the exuded gum liquid from a wild acacia tree. It gets its name because it is mostly produced in Arab countries. Gum Arabic is mainly composed of polysaccharides with a relatively low molecular weight and gum arabic glycoprotein with a relatively high molecular weight. Due to its good water - solubility, preparation is very simple, neither heating nor accelerators are required. The gum Arabic solution dries extremely fast. It can be used for bonding optical lenses, gluing stamps, pasting trademark labels, bonding food packaging, and as a printing and dyeing auxiliary.