Vulcanization open cures

Autoclave curing Open steam curing Hot water curing Self-vulcanizing Cold bond lining and... 

Open steam cure - A method of vulcanization in which the steam is in direct contact with the product being vulcanized at atmospheric pressure. 

Steam cure (open) - A method of vulcanizing rubber parts by exposing them directly to steam. 

Compression set is one of the most widely measured properties of rubber, featuring in a range of material and product specifications and finding use as a sensitive measure of the state of cure in both conventional thermoset rubbers and newer dynamically vulcanized thermoplastic rubbers. Comparative ease of determination has made compression set a popular test for sealing applications, although it is increasingly accepted that the property should not be used in place of the often more relevant stress relaxation. However, it can be relevant to seals where sufficient bodily movement occurs to open up a leakage channel before recovery of shape can take place. 

Practical application of the vulcanization of silicone rubbers using UV light is opening up new areas of application for silicone elastomers, since UV vulcanization enables extremely rapid curing to take place at low temperatures. This process makes it possible to combine silicone elastomers with heat-sensitive plastics, components, chemicals or medicinal products, which would previously have led to the destruction of the material or product because of the high curing temperatures [128]. 

Vulcanization may be by moulding in a press, hot-air or open-steam methods, although the open-steam cured rubbers are often softer than the others. Low-temperature vulcanization (140-160°C) gives vulcanizates with better physical strength than do higher temperatures (> 160°C). 

An excess amount of uncured compound is placed in mold cavity mold is closed and heat and pressure applied, forcing compound to fill mold cavity heat cures (vulcanizes) compound and mold is opened to remove hardened parts... 

Sample preparation. All ingredients were mixed in an open two-roll laboratory mill at room temperature. The rotors operated at a speed ratio of 1 1.4. Rubber compounds were vulcanized in an electrically heated hydraulic press. The compounds were cured into 0.25 mm thick films at 150 °C for 15 min according to the optimum cure time ( 90) derived from the curing curves previously determined by means of a Rubber Process Analyzer (RPA2000 Alpha Technologies). Rectangularshaped specimens were mechanically cut out from the film samples. 

Transmission Oil Cooler Hose compounds are shown in Table 5.24 in which two non-post-cure systems are given. Both the NPC-25 and Zeonet system provides low compression set without post-cure. The temperature of the NPC-25 compound during processing must NOT exceed 85°C, as measured in the stock. During vulcanization, a moisture barrier such as Mylar film should be wrapped on under the nylon tape. The Zeonet cure mechanism also does not require a post-cure and it has the added advantage that it may be used in open steam without a moisture barrier. 

---