The rubber used for hot water bags mainly comes from the latex of tropical rubber trees (natural rubber), and a portion is made from synthetic rubber derived from petroleum.
Ⅰ. Where do the raw materials come from? (Natural rubber)
1.Source plant
The Brazilian hevea rubber tree (Hevea brasiliensis)
Almost all the natural rubber available on the market comes from it.
2.Main production area
- Thailand, Indonesia, Vietnam (top three globally, accounting for 70%)
- China: Hainan, Yunnan, Guangdong (dominant production areas in China)
- Malaysia, India, Côte d'Ivoire, etc.
3. How to harvest (extract rubber)
(1). It can be harvested only after 5 to 7 years of growth.
(2). The cut is made on the bark in the early morning, with a shallow slanting incision (1 to 2 mm deep).
(3). White latex flows out and enters the bowl or cup.
4. Process into raw materials
- Add ammonia water for preservation → Add acid for coagulation → Press into tablets/dry → Form dry gel blocks
- The factory then remixes and sulfurs them, making them into hot water bags
Ⅱ. It could also be synthetic rubber.
- Synthesized from petroleum and natural gas chemical raw materials (such as styrene-butadiene rubber)
- Lower cost, more resistant to aging, but less elastic and having a different feel compared to natural rubber
Ⅲ. One-sentence Summary
Good hot water bag → Natural rubber from Thailand/Indonesia/Hainan;
Cheap version → Synthetic rubber (made from petroleum).
