Magnesium Carbonate in PVC Foam Products: Enhancing Performance and Reducing Costs

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PVC foam products, known for their lightweight nature, sound insulation, thermal insulation, corrosion resistance, and ease of processing, are widely used in building boards, flooring, advertising panels, decorative materials, shoe soles, and other fields. In the formulations of these foam products, besides blowing agents, stabilizers, and lubricants, the selection of fillers is crucial. Magnesium carbonate, as an inorganic filler with mild properties, porous structure, and good thermal stability, plays a very important role in PVC foam products. It not only reduces costs but also regulates cell structure and improves product performance.

PVC foam products

I. Main Roles of Magnesium Carbonate in PVC Foaming

  1. Control Cell Structure: Magnesium carbonate has a microporous structure that can guide the generation and distribution of cells during the foaming process. This results in finer and more uniform cells, which is beneficial for improving the appearance quality and mechanical properties of the products.
  2. Improve Thermal Stability: In high-temperature foaming processing, magnesium carbonate can alleviate the thermal decomposition reaction of PVC. This helps to extend the processing window and avoid problems such as yellowing and cell collapse.
  3. Enhance Product Rigidity and Dimensional Stability: As an inorganic filler, magnesium carbonate enhances the structural strength of PVC foam. This makes foamed boards, shoe soles, and other products more pressure-resistant, wear-resistant, and less prone to deformation during use.
  4. Assist Foaming Reaction: Certain magnesium carbonate products exhibit weak reactivity with blowing agents (such as AC, ADC). At high temperatures, they can undergo a neutralization reaction with the generated gas, which helps to buffer gas pressure and make the cells more stable.
  5. Reduce Costs: Foam products typically use a large amount of filler. Magnesium carbonate, while ensuring performance, can significantly reduce unit cost, making it suitable for mass-produced, economical PVC foam products.

II. Typical Application Areas

  1. PVC Foam Boards (Celuka boards, advertising boards): These boards require high whiteness, rigidity, and flatness. Magnesium carbonate helps to improve cell fineness, enhancing surface smoothness and processing stability.
  2. PVC Foam Flooring (foamed underlayment, elastic layer): Magnesium carbonate can adjust the elasticity and hardness of the floor, improve compression resilience, and reduce shrinkage and deformation during foaming.
  3. Shoe Sole Foaming Materials (PVC micro-foam shoe soles): In PVC shoe sole foaming, magnesium carbonate can enhance foam support, improve resilience, prevent cracking, and enhance the comfort and durability of the products.
  4. Foam Pipes and Wall Panels for Construction: In foam profiles requiring properties such as thermal insulation, lightweight, and high strength, magnesium carbonate as a functional filler is beneficial for improving the overall performance and environmental grade of products.

III. Key Factors Affecting Performance

  1. Particle Size and Distribution: Finer magnesium carbonate can be more evenly dispersed in the PVC system, promoting the uniformity of cell formation. It is recommended to use micron-grade or nano-grade products.
  2. Surface Treatment: Untreated magnesium carbonate may have poor compatibility with the PVC matrix and easily agglomerate. Surface modification with fatty acids or silane coupling agents can significantly improve dispersibility and interfacial bonding strength.
  3. Control of Addition Amount: Excessive addition of magnesium carbonate can affect the plasticity of the melt and the activity of the blowing agent. Reasonable proportioning is necessary. Generally, the recommended dosage is 5%~20% of the total formulation, and the specific amount should be adjusted according to product requirements.
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