What is SBR Rubber Granules?

SBR rubber granules are most commonly produced through the recycling of end-of-life tires (ELTs). This process, known as tire recycling or crumb rubber production, involves several key steps:

Tire Collection and Sorting: Waste tires are collected from various sources, such as tire retailers, auto repair shops, and landfills. They are then sorted to remove any non-tire materials and to separate tires of different sizes and types.

Tire Shredding: The tires are fed into large shredders that reduce them into smaller pieces, typically 2-inch chips. This initial shredding helps to remove steel belts and other large components.

Steel and Fiber Removal: Powerful magnets are used to remove the steel belts and wires from the shredded rubber. Aspiration systems and screens are used to separate the fabric and fiber reinforcement from the rubber.

Granulation: The shredded, steel-free, and fiber-free rubber is then fed into granulators. These machines use rotating knives or hammers to further reduce the rubber into smaller granules. The granulators can be adjusted to produce granules of different sizes, typically ranging from 0.5mm to 6mm.

Screening and Classification: The granulated rubber is passed through a series of screens to separate the granules by size. This ensures that the final product meets the specific size requirements for different applications.

Cleaning (Optional): Depending on the intended use, the SBR granules may undergo additional cleaning processes to remove any remaining contaminants, such as dust or small metal particles.

Ambient or Cryogenic Grinding.
Ambient Grinding: Ambient grinding occurs at or near room temperature. It’s the more common method due to its lower energy requirements and cost-effectiveness. The rubber is shredded and granulated using mechanical processes. While efficient for producing larger granules, it can result in irregularly shaped particles and may generate more heat.

Cryogenic Grinding: Cryogenic grinding involves cooling the rubber to very low temperatures (typically using liquid nitrogen) before grinding. This makes the rubber brittle and easier to shatter into smaller, more uniformly shaped particles. Cryogenic grinding produces finer, more consistent granules, and it’s often used when a higher quality or specific particle size distribution is required. However, it’s more energy-intensive and expensive than ambient grinding.