Rubber
is used as both liquid (latex rubber) and solid form (dry rubber) for
processing. It was described in previous rubber processing post. Latex products
are made from latex concentrate of 60% dry rubber content. Dry rubber products
are made from raw rubber prepared by coagulation of rubber latex. When we
compare latex rubber and dry rubber main drawback is the high water content in
latex rubber. But it has many advantages like it need simple machinery, so law
energy consumption, simple methods for compound preparation, law environmental pollution
etc.
Latex
rubber products are classified as follows,
Thin wall products
- Dipped products
Eg: gloves, balloons, swimming caps
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- Cast products
Eg: Masks, toys
Cellular products
Eg: Foam mattresses
Threads
Eg: textile products, embroidery, shoes,
elastic bands
Coatings
Eg: rubber paints
Both
natural rubber latex and synthetic lattices are used for manufacturing
products. Natural rubber (NR) latex is serum of Hevea Brazilienzis tree. Synthetic
rubber (SR) lattices are developed because of high demand and law availability
of NR latex. They are largely produced by emulsion polymerization.
When
we compare NR latex and SR lattices, SR particles are smaller so high
interfacial area per unit volume, law distribution of particle size and less
spherical in shape. It has high mechanical
stability, but sensitive to coacervating effect of mechanical pressure. Because
of they are synthetic has law tendency of undergoing micro-organic attacks. Wet-gel
strength (the ability of maintaining the structure without collapsing under vulcanization
at higher temperature) is also low in synthetic rubber lattices.
NR
latex will be discussed in future.
