The "leak-proof technology" of the drainage bag: How does the double-layer sealing structure eliminate the risk of side leakage

In the "leakage prevention technology" of the drainage bag, the double-layer sealing structure effectively eliminates the risk of side leakage through multiple physical barriers, material property optimization and process design. The following is an analysis from four dimensions: structural principle, material selection, process guarantee and actual effect:

1. Principle of double-layer sealing structure

1. Double physical barrier

The double-layer structure consists of an inner bag body (directly in contact with liquid) and an outer protective layer (reinforcement and redundant protection).

Inner layer: Use highly flexible and puncture-resistant medical-grade plastics (such as PE/EVA composite film) to ensure safe liquid storage.

Outer layer: Use high-strength materials (such as nylon composite film) to provide mechanical support to prevent external force extrusion or puncture from causing damage to the inner layer.

Interlayer bonding: Through hot melt or high-frequency welding technology, the two layers of material are tightly fitted to eliminate the gap between layers and avoid liquid penetration.

2. Side leakage risk blocking mechanism

Transverse seal reinforcement: A double-layer heat sealing process is used on the side of the drainage bag (stress-prone part) to form two independent sealing lines. Even if the outer seal is slightly damaged due to external force, the inner seal can still independently block the liquid. Edge redundancy design: The double-layer structure forms a "buffer zone" at the edge. Even if the single-layer material cracks due to stress concentration, the other layer can continue to assume the sealing function.

II. Material selection and leakproof performance

1. Inner layer material characteristics

Puncture resistance: High-strength polyethylene (PE) or ethylene-vinyl acetate copolymer (EVA) is used, which can withstand slight contact with sharp objects such as needles and hard objects without breaking.

Low friction coefficient: Reduce liquid residue and reduce the risk of side leakage caused by wall hanging. Chemical stability: Resistant to corrosion by body fluids such as urine and blood, and avoid leakage caused by material aging.

2. Outer layer material characteristics

High toughness: Nylon (PA) or polyester (PET) composite film provides tear and puncture resistance, protecting the inner layer from external damage.

Heat sealing compatibility: It has a similar melting point range with the inner layer material to ensure the reliability of the double-layer heat sealing process.

III. Process assurance and quality control

1. Double-layer heat sealing technology

Heat sealing parameter optimization: By controlling temperature, pressure and time, ensure that the two layers of material are completely fused in the heat sealing area to form a uniform and continuous sealing line.
Sealing strength test: Use bursting pressure test (such as ≥50kPa) and peel strength test (such as ≥15N/15mm) to verify the reliability of double-layer sealing.

2. Edge reinforcement process

Rounded corner design: The edge of the drainage bag adopts a large radius rounded corner to reduce stress concentration and reduce the risk of cracking of the sealing line.
Reinforced patch: Attach high-strength patches to stress-prone parts (such as hanging holes and joints) to enhance local structural strength.