The Novice Guide to Rubber Vulcanization
Charles Goodyear patented the vulcanized rubber product we’ve come to know today in 19th century, after many, MANY, years of trial and error. During this time rubber was largely considered to have no uses and was discarded en masse after the general public realized that the changing temperatures of the weather altered it’s state from solid in the winter, to sticky muck in the summers.
After stumbling upon the revolutionary compound (rubber and sulfur), he finally was able to determine that under steam and pressure applied for an extended period of time at 270+ degrees Fahrenheit, gave him the most uniform results in manufacturing vulcanized rubber. The stiff yet pliable gas impermeability we find in hoses, tires, conveyor belts, et al.
How it works involves “cross-linking”, a bond that links one polymer chain to another to promote a change in the polymers’ physical properties, in this case rubber. Cross-links can be formed by chemical reactions that are initiated by heat, pressure, change in pH, or radiation. For example, mixing of an unpolymerized or partially polymerized resin with specific chemicals called crosslinking reagents results in a chemical reaction that forms cross-links. In which in this article we refer to as rubber vulcanization.
The process in which industries across the planet cure rubber is via autoclave.
An autoclave is a pressure vessel that usually have embedded mechanics to apply various heating types and environmental manipulation in which to treat a product such as rubber.
Autoclaves come into various shapes and sizes and the curing process is likewise various and is application dependent. A product such as automobile radiator hoses require different properties such as increased flexibility, resistance to chemical abrasion, and degradation than that of vehicle tires. Various rubber compounds with differing cross-linking agents such as sulfur or other curing agents require different applications of heat and pressure. Because of this fact it is almost, if not entirely, essential to utilize an autoclave that can meet specific requirements and adjust accordingly to market conditions of your product. But not all autoclaves are the same.
The vulcanizing process in an autoclave is a function of temperature and time. Some autoclaves have somewhat of a limited flexibility in regards to variable modifications in heat, pressure and vacuum. However modern autoclaves, such as Bondtech’s, provide user-friendly PLC (Programmable Logic Controller) control systems that include variable temperatures, pressures, system alarms, cycle timing, recipes held in memory and selection, all of which now Bondtech provides online monitoring and modifications right from the office.
In keeping with the demands of ever changing rubber compounds and curing requirements, Bondtech offers custom tailored autoclaves to perfectly match the needs and the flexibility of the industry as well as providing modifications of your current autoclave as an upgrade.
Joshua McKenzie is a full stack web developer at Bondtech Corporation
