Tuesday, August 31, 2010

Processing Duroplastics

Phenoplasts are made up of phenol (C6.H5.OH – derived from coal tar) and formaldehyde (HCHO). These plastics smell faintly of carbolic acid. Aminoplasts are made up of urea and formaldehyde. Urea is produced from ammonia (NH3) and carbon dioxide (CO2). Because this plastic are brittle, they are mixed with filler (rock flour, asbestos fibre, sawdust, paper scraps). This make the plastic stronger, more elastic and less brittle.

Duroplastic molding material is processed by compression molding. A measured quantity of the preheated molding material is poured into the open mold. The mold is heated continuously, when the compression mold is shut, the plastic mass fills it completely. The mold is heated to between 140oC and 170oC, and the molding pressure is about 100 bar. After it has hardened, the molded part is ejected from the opened mold.

The natural color of phenoplasts is yellowish – brown; finished goods are; radio cases, light switches, socket, plates and tubes. Aminoplast are odourless, tasteless, and colorless. Finished goods are housing and parts for household appliances, telephones and electrical goods. Samples smell of burnt hair when incenerated.

Laminated plastics are stronger then compression moldings. They consist of layer upon layer of paper of textile webs (filler) impregnated with phenolic resins. Heated metal process are use to press the plates of formed layers on to each other. When it is in the form of plates, laminating material is often known as hard paper or hard tissue. Gear wheels, bearing bushes, cable pulleys, sheathing and insulation material are very strong malleable and easily machined. Trade name are; Durcoton, Linex, Novotex and Resistex for hard tissue; Pertinax and Trolitax for hard paper.

Densified Laminated Wood is produced by bonding thin layers of wood with synthetic resins. Finished goods are: furniture, gear wheels, plywood panels. Trade name: Lignotol.

2 comments:

kevin smith said...

scrape it off as much as you can then burn it off ONLY with proper ventillation
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Jayce Deangelo said...

I would pour some nail polish remover and it should come up with a butter knife and rag
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