Flame Retardant Expandable Polystyrene (EPS)

Flame Retardant EPS Resin Bead

Flame retardant grade Expandable Polystyrene (EPS) is a specialized material known for its superior flame retardant capabilities. This product has earned UL laboratory accreditation, attesting to its safety and effectiveness. It features a high molding rate and rapid foaming ability. During processing, the resulting product exhibits a low shrinkage rate and offers a broad operating range, making it compatible with various manufacturing processes including different types of plates, automatic machines, and manual presses.

Model C-102 C-103 C-104 C-105 C-106 C-107 C-108
Bead Size (mm) 1.40-2.00 1.00-1.60 0.85-1.25 0.70-1.00 0.50-0.80 0.40-0.60 0.30-0.50
Foam Density (g/L) 14-20 10-12.5 11-14 12.5-13 13-18 25-33 18-50
Sieve Analysis Efficiency 95% 95% 95% 95% 95% 95% 95%
Pentane Content >6% >6% >6% >6% >6% >6% >6%
Residual Monomer ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3%
Moisture Content ≤1.0% ≤1.0% ≤1.0% ≤1.0% ≤1.0% ≤1.0% ≤1.0%

Flame retardant grade EPS is extensively utilized in a range of sectors. It is a key component in building insulation materials, serves as electrical structural parts, and is used as lightweight filling materials. Additionally, it is ideal for packaging precision electronic equipment, where enhanced protection against fire is crucial.

Flame Retardant EPS Process

The manufacturing process of Expanded Polystyrene (EPS) involves three main stages: pre-expansion, aging, and molding. Initially, raw polystyrene beads containing a blowing agent are heated in a pre-expander, where they expand significantly. Next, these expanded beads are transferred to aging silos to stabilize and allow air to replace some of the blowing agent, enhancing their strength and stability. Finally, the aged beads are placed into molds and subjected to steam, causing them to expand further and fuse together into the desired shape. This process utilizes equipment such as pre-expanders, aging silos, and various molding machines, ensuring the EPS products are lightweight, insulative, and maintain their form.

Pre Expending

EPS pre-expansion is a process used to manufacture polystyrene foam by heating polystyrene beads containing a blowing agent, causing them to expand. During this process, the beads soften at temperatures around 90℃, the blowing agent vaporizes and generates gas, which leads to the beads expanding several times their original volume.

Main steam pressure (Kg/cm²) 5-6
Steam pressure for pre-expanding (Kg/cm²) 1.0-1.2
Temperature in vessel (℃) 108-110
Feedstock (KG) 14-16
Heating time (s) 40-48
Density (g/L) 10.5-13.5

Aging

During the pre-expansion process, the blowing agent evaporates within the beads, and the incorporated blowing agent and water vapor condense into a liquid after exiting the expander. This liquid then dissolves into the styrene monomer, creating a vacuum inside the beads. Therefore, to achieve pressure balance inside and outside the beads, which grants EPS good flexibility and perfect shape, the beads should be stored in a well-ventilated silo for a certain period of time, allowing air to enter the beads.

Aging Time 3-4 Hours

Molding Processing

After aging, fill the EPS into a sealed mold. Inject steam directly into the mold through its holes for a very brief period. As the beads are heated, the blowing agent within them evaporates, causing the beads to soften and expand. These expanded beads fill the entire space of the mold and fuse together due to the confines of the mold. Subsequently, cool and shape the material. The molded products are completed once the mold is released.

Main steam pressure (Kg/cm²) 5-7
Air pressure (Kg/cm²) 5-7
Cooling water pressure (Kg/cm²) 3.5-5
Penetrating pressure (Kg/cm²) 0.5-0.65
Molding pressure (Kg/cm²) 0.5-0.63
Mold fixing pressure (Kg/cm²) 0.4-0.5
Mold moving pressure (Kg/cm²) 0.35-0.45
Penetrating heating time (s) 11-17
Molding heating time (s) 6-10
Heat preserving time (s) 5
water cooling time (s) 15-25
Draining time (s) 2-5
Sealed time (s) 10-15
Cycle time (s) 130-150

EPS Packing

EPS resin beads are available in two packaging options: 25 kilograms per bag and 850 kilograms per bag. A 20-foot container can accommodate up to 17 tons, while a 40-foot container can hold up to 25.2 tons.

EPS 25KG bag