In plain language: Un-sulfured rubber is just soft clay; it becomes an elastic, non-rusting, non-leaking, durable finished hot water bag after being sulfured.
I. Basic Principle
The molecules of raw rubber (raw rubber) are scattered and linear, like a bunch of tangled ropes;
Sulfurization is adding sulfur and applying high temperature and high pressure to cross-link the linear molecules into a network structure, transforming from "raw rubber" to "cooked rubber".
II. What will happen if it is not sulfured (contrast)
Soft and collapsed, unable to form the shape of a hot water bag
When exposed to hot water, it becomes sticky, soft, and deformed
It is prone to cracking, leaking
It is easily aging, shedding debris, having an unpleasant smell
It breaks when stretched, failing to meet safety standards
III. The core function of sulfuring after the process (essential for making hot water bags)
Shape fixation and molding
Making the two rubber sheets adhere and form a fixed shape, ensuring that the bag body does not deform or collapse.
Enhancing elasticity and toughness
When pulled, it can return to its original shape, and when pressed, it does not deform. It is not likely to break during daily rubbing, bending, or folding.
Resistant to high temperatures and hot water
It does not soften, melt, or become sticky when filled with 80-90℃ hot water.
Sealing and preventing leakage
The seams and sealing areas are solidified through sulfuring, making the sealing stronger and less prone to water leakage.
Anti-aging and extending lifespan
Resistant to oxidation and alternating temperatures, usable for 2-3 years; without sulfuring, it will age and crack after a few months.
Physical strength meets standards
The tensile strength and elongation rate reach national standards, with no burst when under pressure, and no breakage when squeezed.
Removing rubber odor and stabilizing the material
Reducing the pungent smell of raw rubber, the material performance is stable, and no harmful substances are released.
IV. Summary in one sentence
Un-sulfured rubber for hot water bags is just semi-finished rubber sheet. Once filled with hot water, it sticks, cracks, and leaks;
Sulfuring is the necessary process to transform raw rubber into a safe, elastic, hot water-resistant, durable finished product, and it is also a mandatory requirement for meeting national standards upon leaving the factory.
