The Hindu Business Line : Grading of rubber

THIRUVANANTHAPURAM: Natural Rubber (NR) in sheet forms is the oldest and the most popular type. Two types of sheet rubbers are produced and marketed in the international market, namely the Ribbed Smoked Sheets (RSS) and the Air Dried Sheets (ADS). Among these, RSS is the most popular and is available for volume consumption.

RSS is used as raw materials in industrial sectors such as tyre industry, which is the biggest consumer. The second biggest users are rubber elastics, rubber erasers, rubber tubes and shoes and rubber sole. RSS can be divided into following 6 categories.

Ribbed smoked sheet no.1 Extra (RSS 1 X). This category of rubber sheet must be wholly flawless and totally not mouldy. Ribbed smoked sheet no.1 (RSS 1). This category of rubber sheet can be a little mottled on the surface of the sheet and on the wrapper but must be totally flawless.

Ribbed smoked sheet no.2 (RSS 2). RSS 2 can sustain mottled and rust on the surface, in the sheet and on the package but mouldy condition must not exceed 5 per cent f the samples.

Ribbed smoked sheet no.3 (RSS 3). RSS 3 accounts for more than 80 per cent of all RSS production. Mouldy condition of this category is the same as that of RSS 2 but must not exceed 10 per cent of the samples.

Ribbed smoked sheet no.4 (RSS 4). Mouldy condition is the same as RSS 2 and RSS 3 but must not exceed 20 per cent of the samples.

Ribbed smoked sheet no.5 (RSS 5). Mouldy condition is the same as RSS 2, RSS 3 and RSS 4 but must not exceed 30 per cent of the samples.