How does the uniformity of foaming in rubber-plastic insulation products affect their insulation performance?

1. Uniform Foaming: Ensures Optimal Insulation Performance

When foaming is uniform, tiny, densely distributed, and enclosed bubbles of uniform size form within the product. These bubbles effectively block heat transfer:

• The air flow within these tiny, enclosed bubbles is extremely low, significantly reducing convection heat transfer.
• The uniform bubble structure prevents heat from penetrating through weak points, forming a continuous, stable insulation barrier.

This maintains a low overall thermal conductivity (typically, the thermal conductivity of qualified rubber-plastic insulation materials is ≤0.034 W/(m·K)), thus achieving optimal insulation.

2. Uneven Foaming: Significantly Reduces Insulation Performance

Uneven foaming (such as large variations in bubble size, areas without bubbles, or broken/connected bubbles) can directly damage the insulation structure, leading to reduced insulation performance. Specific issues include:

• Locally Dense Areas (No/Low Bubbles): Dense areas lack bubble insulation. The thermal conductivity of the rubber-plastic matrix itself is much higher than that of air, creating “heat channels” that rapidly transfer heat and create “insulation dead zones.”
• Large/Connected Bubbles: Excessively large bubbles are prone to rupture, or multiple bubbles connect to form “air convection channels.” Air flow within these channels accelerates heat exchange and significantly increases overall thermal conductivity.
• Overall Performance Unstable: Even if foaming is acceptable in some areas, an uneven structure can cause fluctuations in the overall insulation performance of the product, making it unable to meet stable insulation requirements. Over time, the uneven bubble structure can accelerate aging, further exacerbating insulation degradation.