In the field of polymer foam materials, density serves as a core parameter determining the physical properties and application scenarios of the material. This article will focus on PVC foam board as the primary subject, systematically explaining its common density classification system and technical characteristics. According to international industry standards, the density grades of PVC foam boards are primarily divided into three major categories: low density, medium density, and high density. Each density specification corresponds to unique microstructural and macroscopic performance characteristics.Low-density PVC foam board typically refers to foam materials with a density range of 0.3–0.5 g/cm³. This type of board utilizes specialized foaming processes to form a honeycomb-like structure, achieving a closed-cell rate of over 85%. Due to an air volume ratio of 60%–70%, boards in this grade maintain fundamental mechanical properties while exhibiting exceptionally low thermal conductivity, often below 0.045 W/(m·K). As a result, they are particularly suitable for applications requiring thermal insulation. In the production of laminated PVC foam board, low-density cores are often combined with high-strength surface layers, creating composite structures that are both lightweight and rigid, meeting the demands of sectors such as advertising displays and lightweight partitioning.Medium-density PVC foam board, with a density range of 0.5–0.7 g/cm³, represents the most widely used category in the market. Through precise control of the foaming process, this type of board achieves an optimal balance between cellular structure and polymer matrix. Its flexural strength typically ranges from 12 to 18 MPa, while its impact resistance is 30%–50% higher than that of low-density boards. Notably, PVC Celuka foam sheet produced using the Celuka process falls within this density range. Its unique integral skin structure—featuring a high-density surface layer and a low-density core—provides exceptional surface flatness and machining performance, making it ideal for precision carving and thermal forming processes.High-density PVC foam board refers to materials with a density exceeding 0.7 g/cm³, with some specialized varieties even reaching 0.9–1.2 g/cm³. These boards feature a significantly reduced cellular diameter, typically controlled within 50–100 micrometers, resulting in a material structure that approaches that of solid polymers. The Rockwell hardness (R scale) of such boards can reach 85–95, with water absorption rates as low as 0.1%–0.3% after 24-hour immersion. In structural applications, high-density boards demonstrate compressive strengths of 25 MPa or higher. PVC co-extruded foam board often utilizes high-density surface layers combined with medium-density cores, creating a gradient density structure that offers both excellent surface wear resistance and overall lightweight properties.It is worth noting that the density classification of plastic foam board is not an isolated indicator but is closely interrelated with other performance parameters. For instance, as density increases, the material’s thermal insulation performance gradually decreases, while its load-bearing capacity and surface hardness correspondingly improve. In practical applications, the selection of density grade must be comprehensively considered alongside thickness specifications, surface treatment requirements,pvc foam board and environmental factors. For example, in humid environments, high-density boards exhibit significantly lower moisture absorption expansion rates, typically not exceeding 0.5%.From a technical development perspective, the innovation in density control technologies for PVC foam boards is ongoing. Advanced physical foaming agents and multi-layer co-extrusion technologies enable the production of foam boards with gradient density structures within a single sheet pvc foam board. These functionally graded materials can simultaneously possess the thermal insulation properties of low-density foams and the load-bearing capacity of high-density materials, showcasing the immense potential of PVC foam board in innovative applications.In conclusion, a deep understanding of the density classification system for PVC foam boards not only aids in the scientific selection of materials but also provides a technical foundation for innovative product design. With continuous advancements in material technology,pvc foam board more precise density control methods and novel composite structures will further expand the application boundaries of this versatile material.
