In building energy conservation, HVAC, and industrial piping systems, rubber and plastic insulation materials are a mature and widely used flexible insulation material. They exhibit stable performance in hot and cold water pipes, air conditioning ducts, and equipment insulation. Understanding the insulation effect of rubber and plastic materials hinges on their thermal insulation principle. This article will systematically explain the thermal insulation principle of rubber and plastic insulation materials from the perspectives of material structure and heat conduction mechanisms.

I. Basic Properties of Rubber and Plastic Insulation Materials

Rubber and plastic insulation materials are typically based on rubber and polymer materials, manufactured through a foaming process. They are closed-cell flexible insulation materials. Their internal structure forms a large number of independent, closed micropores, which is the core basis for their thermal insulation performance.

From a material properties perspective, rubber and plastic insulation materials possess the following characteristics:

Soft and flexible structure

High closed-cell ratio

Stable thermal conductivity

Low water absorption

Strong construction adaptability

II. Core Insulation Objectives of Rubber and Plastic Insulation Materials

In practical applications, the insulation of rubber and plastic insulation materials is mainly used to achieve the following objectives:

1. Reduce heat loss between hot and cold media

2. Prevent condensation on pipe and equipment surfaces

3. Improve system operating efficiency

4. Maintain stable temperature of the transported medium

The insulation principle revolves around these objectives.

III. Overview of the Insulation Principle of Rubber and Plastic Insulation Materials

The insulation principle of rubber and plastic insulation materials mainly stems from the following aspects:

Suppression of air convection by the closed-cell structure

Blocking of heat conduction by the low thermal conductivity gas layer

Dispersion of heat flow paths by the solid skeleton

Reduction of thermal bridges by the flexible structure

These factors together constitute a stable insulation system for rubber and plastic materials.

IV. The Inhibiting Effect of Closed-Cell Structure on Heat Conduction

1. Independent Closed Bubbles Restrict Air Flow

The interior of rubber and plastic insulation materials consists of numerous non-interconnected closed-cell bubbles. Each bubble contains stationary gas, which prevents:

Air convection from occurring.

Heat transfer primarily relies on molecular conduction.

Due to the low thermal conductivity of gases, this structure is highly advantageous for insulation.

2. Reduces Heat Loss Due to Gas Convection

Compared to open-cell materials, the closed-cell structure effectively avoids heat exchange caused by airflow, improving the stability of insulation performance from a structural perspective.

V. The Influence of Solid Skeleton on Heat Flow Path

The solid portion of rubber and plastic materials exhibits a continuous but not dense skeletal structure. During heat conduction:

It must bypass the bubble structure.

The heat flow path is lengthened.

Heat transfer efficiency decreases accordingly.

This "tortuous heat transfer path" is one of the important reasons for the low thermal conductivity of rubber and plastic materials.

VI. Flexible Structures for Ensuring Insulation Continuity

1. Reducing Thermal Bridges During Construction

Rubber-plastic insulation materials are flexible, cuttable, and can be tightly fitted to pipe and equipment surfaces, enabling them to:

Reduce joint gaps

Reduce the probability of thermal bridge formation

Maintain the integrity of the insulation layer

2. Adapt to Thermal Expansion and Contraction

Under cyclical heating and cooling conditions, the flexible structure can absorb deformation stress, preventing a decrease in insulation performance due to material cracking.

VII. The Auxiliary Role of Moisture-Proof Performance in Insulation

Rubber-plastic insulation materials have a high closed-cell rate, making it difficult for moisture to penetrate the internal structure:

Low water absorption rate

The thermal conductivity is not easily diminished by moisture.

This is crucial for maintaining long-term stable insulation performance, especially suitable for cold water pipes and refrigeration systems.

In summary, the insulation principle of rubber-plastic insulation materials mainly relies on a composite insulation system formed by its highly closed-cell structure, static gas insulation layer, and flexible continuous structure. By effectively suppressing heat conduction and air convection, rubber and plastic materials achieve stable and reliable thermal insulation effects in building and HVAC systems.