Rosin is a very interesting substance

Rosin is an amorphous, brittle substance that has a glassy structure and color from light yellow to dark red. It is obtained after distilling the volatile component from the resin of coniferous trees. Chemical properties of rosin (up to 90% of resin acids, including basic - abietic) make it insoluble in water, but dissolving in esters, alcohol, chloroform and benzene. When heated to 50-120 C (for different grades) the rosin bars soften.

Where did the word "rosin" come from? This is most likely the distorted name of the ancient Greek city of Colophon, around which grew trees that give such a substance. In ancient times (more than three thousand years ago) turpentine was obtained from resins by heating, and the dry residue was just a primitive rosin substance.

Rosin is an accessory, without which you can not play, for example, on a violin, viola, double bass, cello. When rubbing a bow with a piece of this substance, free molecules are formed that give a certain grip to the string, which helps to extract sound. Such rosin is often produced in a non-industrial way from resins, collected exclusively in the fall with the addition of "secret" ingredients, which are their own for each company (metal, silver and even gold dust can be added, etc.). In addition, rosin used to rub the soles before sports, for example, wrestlers, as well as the saddle of jockeys before the jumps.

Rosin is a substance that has been widely used and used in industry. In former times, it was in demand in soap making, the production of plasters, sealing wax. Today, compositions with rosin are used for fastening glass components of lamps to socles, for the production of varnishes, for printing, for soldering, and for the paper industry. And everywhere its main property is used - the ability to create sticky joints when heated.

Production of rosin in general has not changed over the millennia. The raw material (tarred stumps, collected resin - gum) is placed in cubes, where it is steamed or heated on fire. About a kilogram of turpentine produces about 12 kg of turpentine (distilled) and 70 kg of rosin, which is boiled to remove liquid and placed in containers. If the substance is extracted from the stumps, they are pre-ground, and then the mixture of chips and water is subjected to the extraction process. From one cubic meter of tarred wood it is possible to receive about forty kilograms of rosin.

What are the main normative acts used by enterprises that produce rosin? GOST 19113 - 84, in particular, contains the basic requirements for products and a number of production parameters. From it we can find out what kind of appearance should be in rosin, what is the permissible density, water content, softening temperature, acid number, etc. The document also specifies the requirements for the safety of the production process (rosin is a moderately hazardous substance, t. Its aerosol can cause irritation), acceptance rules, finished product analysis methods, storage rules and guarantees.