The free foaming process involves extruding a PVC compound mixed with a foaming agent through a die into atmospheric pressure. Upon exiting, the material expands freely in all directions—hence the name “free foaming.” This uncontrolled expansion creates a foam structure with a relatively uniform cell distribution throughout the cross-section. The surface of a free foamed PVC foam board is typically porous and requires lamination or coating to achieve a smooth, durable finish for many end uses. This process tends to produce boards with lower density compared to skin-foamed products, making them lighter and often more cost-effective. However, the open surface can be more susceptible to moisture ingress if not properly sealed.The Skin Foaming (Celuka) ProcessIn contrast, the Celuka process, or skin foaming, employs a specialized die with a calibrated mandrel. The extrudate exits the die into a cooled and shaped calibration unit. The outer surface of the material cools and solidifies almost instantly against the calibrator, forming a hard, integral, and non-porous skin. Meanwhile, the core of the material continues to expand inward, filling the space within this solid shell. This results in a PVC Celuka foam sheet with a unique structure: a high-density, smooth, and durable solid skin encapsulating a lower-density foamed core. The laminated PVC foam board produced via free foaming is an alternative to achieve a good surface, but the Celuka process creates the smooth skin intrinsically during extrusion, eliminating the need for an additional lamination step for many applications. The term Celuka PVC has become synonymous with this integral-skinned, fine-celled foam product pvc celuka foam sheet.Comparative Product PropertiesThe divergent manufacturing processes lead to markedly different product properties:
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Surface Quality & Integrity: Celuka PVC products boast a high-gloss, extremely smooth, and non-porous solid skin directly from extrusion. This skin provides excellent resistance to moisture, chemicals, and physical abrasion. A free foamed PVC foam board, with its porous surface, generally requires post-production lamination (becoming a laminated PVC foam board) to achieve comparable surface protection and aesthetics. The integral skin of a Celuka sheet is inherently waterproof, whereas the core of a free-foamed board can be vulnerable if the protective layer is compromised pvc celuka foam sheet.2.
Density & Weight: Free foamed boards usually have a lower overall density, making them lighter. Celuka boards have a higher average density due to the solid skin,pvc celuka foam sheet resulting in a heavier, more rigid feel pvc celuka foam sheet.3.
Mechanical Strength: The solid skin of the PVC Celuka foam sheet gives it superior bending strength, stiffness, and impact resistance compared to a free-foamed board of similar thickness. It is less prone to surface denting and offers better screw-holding power.4.
Machinability & Applications: Both types machine well, but their optimal uses differ. The homogeneous, porous structure of free foamed boards makes them ideal for thermoforming, routing, and applications where weight is critical, pvc celuka foam sheet provided the surface is coated pvc celuka foam sheet. The robust, pvc celuka foam sheet ready-to-use surface of Celuka foam makes it the preferred choice for direct painting,pvc celuka foam sheet printing, and for applications demanding high structural integrity and moisture resistance without additional finishing, such as in signage, displays, and construction panels pvc celuka foam sheet.
In summary, the choice between a free-foamed and a skin-foamed (Celuka) polyvinyl chloride foam board hinges on the application's requirements for surface quality, structural strength, weight, and environmental exposure. The free foaming process offers a lightweight, economical core material often used with lamination, while the Celuka process delivers a premium, self-skinned product with outstanding inherent durability and a ready-to-finish surface.
