The main components of the rubber hot water bag are based on natural rubber, combined with vulcanization system, protective system, filling system and other additives. The specific composition is as follows:
Ⅰ. Main substrate
- Natural rubber (NR)
The core raw material, typically accounting for 45% to 60%, provides high elasticity, tensile strength and softness, and is the basic material for hot water bags.
- Some low-cost products may incorporate recycled rubber to reduce costs, but this will affect the elasticity and durability.
II. Vulcanization System (Determining Crosslinking and Formation)
- Sulfur: The main vulcanizing agent, which causes the rubber molecules to form a network structure.
- Accelerators: They accelerate the vulcanization process and are commonly composed of thiazole and xanthate types.
- Active agents: Zinc oxide, stearic acid, which enhance the vulcanization efficiency and crosslink density.
III. Protection System (Anti-Aging)
- Antioxidant: Prevents rubber from cracking and hardening after being heated and oxidized, thereby extending its service life.
- Stabilizer: Enhances heat resistance and water resistance.
IV. Filling and Processing System
- Carbon black / White carbon black: Enhances strength, wear resistance, and improves processing performance.
- Calcium carbonate, clay: Commonly used fillers, reduces costs, and regulates hardness.
- Softeners / Plasticizers: Such as operation oil, paraffin, improve the plasticity of rubber, facilitating molding.
V. Other Additives
- Coloring agent: Pigments or color pastes, used to produce common colors such as red, pink, and blue.
- Demoulding agent: Facilitates the removal of the product from the mold after vulcanization.
