What Is Natural Resin?

Natural resins are mainly derived from amorphous semi-solid or solid organic matter from plant exudates. The characteristic is that it becomes soft when heated, can be melted, and has a tendency to flow under the action of stress. It is generally insoluble in water, but soluble in alcohol, ether, ketone and other organic solvents.

Natural resin

Natural resin

There are many types of these substances, which are derived from plants, mainly

Natural resins are mainly used as coatings (see

Rosin tincture is refined from the viscous liquid secreted by pine trees. It is a transparent and brittle solid substance with a color from yellowish to brownish red. From its collection method can be divided into gum rosin and wood rosin. Gum rosin is also called gum rosin. The viscous juice collected from the rosin trunk was cut directly, called wool rosin; after the turpentine was steamed out, the refined gum rosin was obtained, which was characterized by light color, high acid value and high softening point. Wood rosin is prepared from residual rosin piles or tree roots by solvent extraction and distillation to separate volatile oil, which is not as good as gum rosin. The quality of rosin is classified according to the color, acid value, softening point, etc. More than 90% of rosin is various isomeric rosin acids, and the rest are esters of these acids and some unsaponifiables. Abietic acid is a weak acid that can undergo reactions such as esterification and saponification. It is sensitive to the action of oxygen. After oxidation, the color of rosin becomes darker and it can polymerize into dimers. It can be decomposed by heat at 250 ~ 260 ° C. Rosin is mainly used in soap, papermaking and other industries. It is made into various processed products such as rosin soap, rosin ester, etc. and used in coating industry. Rosin production in China is very large, mainly produced in Southwest and South China.

A kind of fossil resin obtained by long-term burial of resin secreted from the amber pine tree, mostly used in jewelry and other crafts.

Coba resins and mastics are resins derived from woody plant secretions in Africa and New Zealand. There are many names according to the origin and plant source. Congo Coba, Madagascar Coba, etc. are produced in Africa, Colico Coba, etc. are produced in New Zealand, and Manila Coba are produced in the Philippines. Directly taken from plants is soft coba, such as Manila coba; tree secretions are buried in the ground for a long time and transformed into fossil resins. Hard coba or fossil coba, such as Congo Coba The crude resin is refined to obtain various Cobar resins. Their softening point is about 100 ~ 300 ° C, and most of them are about 150 ° C. Coba resin is mainly composed of resin acid, while mastic resin is the secretion of Bornaceae plants. Mar resins and Coba resins were used as raw materials for coatings in the 19th century, and they are almost no longer used.

Shellac Also known as shellac, shellac is a kind of animal resin that accumulates on the branches of lac insects in India, Malaysia and Yunnan, China. The secretion peeled from the branch is refined into shellac. Shellac is soluble in ethanol. There are still a few applications in the coatings industry.