1What is rubber band made of?
Main material is "rubber", usually natural rubber, but some types of synthetic rubber are also used to obtain certain specific quality depending on the application. Besides, fillers such as calcium carbonate, carbon black, clay and additives like sulfur, stearic acid, zinc oxide, wax, oil, accelerators are mixed into rubber as ingredients.
2What is natural rubber?
Natural rubber used for making rubber band is in block form made from latex emulsion collected from rubber tree called Hevea Brasiliensis planted in very large scale in tropical countries such as Thailand, Indonesia and Malaysia.
3Why rubber has to be vulcanized?
Natural rubber itself is soft, less resilient, broken down easily when over stretched and not able to return to the original shape after being stretched. Moreover, it is easily damaged by heat, sunlight, oil, oxygen and solvent. During a process called vulcanization, the sulphur molecule becomes a bridge between rubber molecules and forms a three dimensional network with help of other ingredients (just like fishing net made of many lines of thread). This network improves the above weaknesses of natural rubber for practical use. Generally, the higher the rubber content, the higher the resilience and elasticity.
4What is happening inside rubber during vulcanization?
At the vulcanizing temperature (practically, 140-200°C)., a complex chemical reaction starts to occur and leads to the formation of sulphur crosslink as shown schematically below,
5How should rubber band be stored?
Products made of natural rubber are, in general, aged faster by exposure to heat, air and sun light. Therefore, rubber bands should be packed, preferably in air tight bag or container, and stored in cool and dark place for securing longer life.
6What is CEC's "Latex Free Rubber Band"?
CEC's Latex Free rubber band is made of a type of solid synthetic rubber which does not contain natural rubber just as gloves made from liquid synthetic rubber (called "Synthetic Latex") such as nitrile latex.
Word "Latex Free" is often used to mean "Not made from natural rubber latex" or "Not contain natural rubber" in order to indicate indirectly "No risk of latex protein allergy".
Natural rubber contains a series of water soluble or extractable proteins (called "EP") which were reported to be a cause of allergy to the human body when contacted over a long period.
Particular attention was bought up over the use of surgical and examination gloves. As these thin rubber gloves are commonly manufactured using liquid natural rubber (called "Latex") collected from rubber trees, they are called "Latex Gloves".
7Can CEC natural rubber band be used for human contact?
Yes, CEC rubber bands are considered safe in term of protein allergy for non-medical application because they are made of solid (dry) natural rubber and are further washed in steam and fresh water at the final stage of rubber band production in CEC.
8What is the allowable extractable protein (EP) content level for safety against latex allergy?
Although no definite figure has been officially announced by any international organization yet, it is generally known that EP content lower than about 100 mg/g does not cause allergy except for hypersensitive person.
9What is the allowable extractable protein (EP) content level for safety against latex allergy?
Although no definite figure has been officially announced by any international organization yet, it is generally known that EP content lower than about 100 mg/g does not cause allergy except for hypersensitive person.
