Rubber Compound: Raw Rubber Washed, Dried and Mixed with Sulphur on Hot Rolls (Thorpe, 1913)

How a rubber works of 1913 turned raw rubber into a 'mixing' ready for shaping and curing: the rubber is washed between corrugated rolls under running water, dried on racks, broken down on hot smooth rolls until plastic, and then worked together with fillers and finally sulphur into an even dough. Very few goods were made of rubber and sulphur alone: pure mixings cost too much and are too soft for most uses. Unknown: which fillers, and how much of them and of sulphur. Thorpe names the kinds of materials but gives no mixing. Source: T. E. Thorpe, Dictionary of Applied Chemistry vol. IV (1913), pp. 586-587. Picture: Fig. 1, a washing machine.

中级

3-4 days drying

说明

Steep and wash the rubber

Cut the raw rubber into lumps or slabs and steep them for some hours in warm water. Pass them again and again through corrugated, diamond-cut or fluted rolls running at a speed difference of 6 : 4 down to one tooth, with a stream of water on the rubber, until the rough crepe-like sheet is clean and thin.

此步骤所需材料：

烟胶片1 raw rubber

水1 warm, then running

所需工具：

双辊开炼机

Dry on racks

Hang the sheet on racks in a drying room until it holds only about 0.25-0.5 per cent moisture: about 3-4 days at about 80°F with good ventilation. Cooler, drier air is better, as warm rubber turns soft and tacky.

所需工具：

晾干架

Break it down

Pass the dry rubber repeatedly through the steam-heated smooth rolls of the mixing machine, which run at different speeds, tightening the rolls gradually until the rubber is thoroughly plastic.

所需工具：

双辊开炼机

Mix in the fillers and sulphur

Add the other materials gradually: reclaimed rubber, ground waste, 'substitute' and other organic fillers first, then the minerals and the sulphur last. Work it into a thoroughly even dough without overworking ('tiring') the rubber.

此步骤所需材料：