Butyl Rubber Stopper Butyl Rubber Stopper, also called IIR Stopper, Plug & Bung, as a medicine glass bottle sealing plug or cover, which made from butyl rubber materials by compression tooling.
Common Medicine Rubber Butyl Stopper: Bromobutyl Rubber Stopper and Chlorobutyl Rubber Stoppers. Butyl rubber is also called IIR, “short for Isobutylene Isoprene Rubber”. Butyl rubber has good performance of chemical stability and thermal stability, the most prominent among which is the air tightness and watertightness. Its air permeability is only a 1/7 of natural rubber, and 1/5 of styrene butadiene rubber, while the vapor permeability is 1/200 of natural rubber, and 1/140 of styrene butadiene rubber 1/140. So it is mainly used for manufacturing various inner tubes, steam pipes, water tires, dam bottom and gaskets and other rubber products.
Common Medicine Rubber Butyl Stopper: Bromobutyl Rubber Stopper and Chlorobutyl Rubber Stoppers.
Chlorobutyl rubber and Bromobutyl rubber belong to butyl rubber derivatives by reacting butyl rubber, also known as halogenated butyl rubbers, which helps butyl rubbers to improve processing performance and expand a wider range of application.
1. Stabilizer Content:
Bromobutyl rubber contains active Bromine element, which result in lower storage stability and easy self-vulcanization. Therefore, Bromobutyl rubber usually need to be added stabilizer. However, chlorine element’s inertness in butyl rubber is stronger than Bromine element’s, so chlorobutyl rubber has a higher storage stability and then there’s usually no need to add stabilizer to butyl rubber, which makes inner contents higher purify.
2. Antioxidant Content:
Both of Chlorobutyl rubber and Bromobutyl rubber share the same proportion.
As industrial products, there is no essential difference in properties.
Bromobutyl rubber has high cure reactivity and it has a wide range of available curing systems. Common curing systems all are available for Bromobutyl rubber and the cure rate is faster.
Industrial products have a high requirement for physical properties, which usually adopt Brominated phenolic resin, stearic acid, zinc oxide, thiazole and thiuram accelerator as curing systems. In early period, Pharmaceutical Stoppers also adopted the these systems, but with a period of application, researchers found that these systems have certain influence on compatibility between medical Stoppers and Pharmaceutical. At present, domestic Bromobutyl rubber usually choose sulphur for curing for high efficiency and low cost.
However, Bromobutyl rubber has relatively low reactivity, which cause limitation of choosing curing systems. Besides, it still has strict requirement for manufacturing technique (relatively difficult). In the early days, phenolic resin, stearic acid and zinc oxide are usually used as curing system, contributing to good heat resistance. However, product’s extraction liquid is color-developing, which will affect Pharmaceutical clarity. Now, these curing systems are not used any more.