Product Chalking After Outdoor Use

In the rotational molding production process, the product exhibits the quality defect of 「Product Chalking After Outdoor Use」. The specific manifestation is that the product surface chalks after outdoor use. This defect is relatively common when processing powder materials such as LLDPE, HDPE, PVC, and PA, and its occurrence conditions are usually related to unreasonable settings of heating temperature and time, rotation speed ratio, cooling rate, and mold wall thickness. When the Product Chalking After Outdoor Use situation is severe, it will cause a series of chain quality defects in the product in terms of appearance, dimensional accuracy, and mechanical properties, which not only reduces the product's use functionality and safety, but also directly increases the scrap rate and production cost. Therefore, this problem needs to be systematically diagnosed and optimized from multiple dimensions such as material selection, the rotational molding machine, the heating oven, the rotating arm, the cooling station status, and heating temperature and time, rotation speed ratio, cooling rate, and mold wall thickness.

1. Poor weather resistance of the resin. Material selection and handling are the foundation of molding quality. Intrinsic properties of the resin such as molecular weight, molecular weight distribution, and melt index determine its processing window and final performance. Factors such as excessive raw material moisture content, impurity mixing, and improper proportion of recycled material will all cause various defects during processing. 2. No UV stabilizer added. This factor leading to the problem reflects that certain process conditions or material properties in rotational '2079851475616104453ing have not met the optimal molding requirements. Such problems are often cumulative and hidden, and should be investigated and verified as key focus items during process debugging and finalization to ensure that hidden dangers are eliminated from the source. 3. Resin degradation. Material selection and handling are the foundation of molding quality. Intrinsic properties of the resin such as molecular weight, molecular weight distribution, and melt index determine its processing window and final performance. Factors such as excessive raw material moisture content, impurity mixing, and improper proportion of recycled material will all cause various defects during processing. In terms of equipment maintenance, the regular overhaul and accuracy confirmation of the rotational molding machine, heating oven, rotating arm, and cooling station are not in place, causing the actual operating parameters of the equipment to deviate from process requirements, which will also become a potential inducement of the Product Chalking After Outdoor Use problem.

1. Add UV stabilizers and antioxidants. Formula and ratio adjustments should be determined on the basis of laboratory small-scale tests, and then verified in online pilot tests. Any change in the formula should be recorded and evaluated for its comprehensive impact on product performance. Automatic metering and batching devices can effectively reduce manual batching errors and batch-to-batch fluctuations. 2. Select a weather-resistant resin. Before introducing new tools, new materials, or new methods, adequate applicability evaluation and small-batch verification should be carried out. It is recommended to first conduct offline tests or simulation analysis outside production conditions, and introduce them into the formal production line only after confirming effectiveness and safety. Make good change management records to facilitate subsequent traceability and experience accumulation. 3. Surface coating protection. Protective treatment of equipment and molds can effectively extend service life and maintain accuracy. Exposed precision surfaces should be coated with anti-rust oil, and molds not used for a long time should be stored sealed. Anti-rust and anti-corrosion agents should be added to the cooling water, and filters should be installed on pipelines. Good protective habits can reduce unplanned downtime and lower maintenance costs. In terms of material management, incoming inspection of raw materials and in-process inspection of work-in-progress products should be strengthened, and the key performance indicators of powder materials such as LLDPE, HDPE, PVC, and PA should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the 「Product Chalking After Outdoor Use」 problem can be attributed to the combined effects of multiple factors such as poor weather resistance of the resin and no UV stabilizer added. To solve this problem, it is necessary to start from aspects such as adding UV stabilizers and antioxidants and selecting a weather-resistant resin and take systematic treatment measures. In actual production, it is recommended to establish a prevention and rapid response mechanism for this problem, and achieve stable production and continuous improvement through powder melting uniformity and product wall thickness control.