Phenol formaldehyde resin is a synthetic resin having the properties of thermosets or thermosets. Such resins are oligomeric or liquid substances obtained by polycondensation of formaldehyde with phenol in an acidic or alkaline medium (resole, novolac resins or bakelites). This further affects the properties of the final product.
Properties of phenol-formaldehyde resins
Phenol formaldehyde resin (formula [-C6H3 (OH) -CH2-] n) has high electrical insulation, good corrosion and mechanical resistance. It is highly soluble in aromatic and aliphatic hydrocarbons, ketones and chlorine solvents. Also soluble in polar solutions and aqueous solutions of alkalis. After hardening, phenol-formaldehyde resins turn into densely cross-linked polymers of microheterogeneous amorphous structure.
Where is phenol-formaldehyde resin used?
- in the production of plastics: hardened resins are called resites, hardened in the presence of petroleum sulfonic acids - carbolites, in the presence of lactic acid - neoleukorites;
- in the production of varnishes, synthetic adhesives, bearings, brake linings, balls for billiards;
- from carbolite (hardened phenol-formaldehyde resin) multimer cases of some Soviet models were made;
- this substance is also used as a binder component for the production of filled press compositions with various fillers (wood flour, fiberglass, cellulose), wood-shaving and wood-fiber boards, casting and impregnating compositions (for fiber-filled and woven materials, for plywood), glues.
Phenol-formaldehyde resin: production and ecology
Both formaldehyde and phenol, used in the production of phenol-formaldehyde resins, are toxic and flammable. Phenol formaldehyde resin negatively affects the human body: causes eczema and dermatitis. Moreover, formaldehyde also has a carcinogenic effect.
Bakelite is a hardening product of phenol-formaldehyde resin in the presence of a catalyst. This substance is of great importance in various areas of human life. Bakelite does not conduct heat well, but shows good resistance to mechanical damage: shock, shock, friction, or pressure. It can be processed on a special lathe. It is a good insulator. Diluted alkalis, acids and water do not act on it, with the exception of concentrated sulfuric or nitric acids. It is steady up to +300 degrees, at a higher temperature of combustion does not occur.
It was originally created in order to become a substitute for shellac - a special resin produced in nature by tropical varnish worms.
Phenoplasts. Application
Phenoplasts are plastics that are obtained by hardening formaldehyde resins at elevated temperatures in combination with any filler. Currently, this material is unsurpassed in its properties. With the use of phenolic plastics are made:
- a substance intended for the manufacture of printed circuit boards - getinaks;
- a substance for creating a structural material - textolite;
- inexpensive items for board games - checkers, dominoes, chess;
- some elements of kitchen utensils: handles for gas stoves, teapots and knives, pots and pans;
- glue bakelito-phenolic;
- electrical products - sockets, plugs, electricity meters, switches, relays, electric motor housings, terminal boxes, magnetic starters, etc .;
- parts for mechanical engineering, for example, steps for escalators, various tips and handles;
- jewelry, souvenirs, stationery, some watch details.