Discoloration and embrittlement of the product after ultraviolet irradiation

In the extrusion '2079851475616104457 production process, the product exhibits the quality defect of "Discoloration and embrittlement of the product after ultraviolet irradiation".The specific manifestation is The product yellows and becomes brittle after outdoor use.This defect is more common when processing materials such as HDPE, PP, PVC and PC, and its occurrence is usually related to unreasonable settings of melt temperature, extrusion speed, blowing pressure and mold temperature.When the Discoloration and embrittlement of the product after ultraviolet irradiation situation is severe, it will cause a series of chain quality defects in the product's appearance, dimensional accuracy, mechanical properties and other aspects, which not only reduces the product's functionality and safety in use, but also directly increases the scrap rate and production cost.Therefore, this problem requires systematic diagnosis and optimization from multiple dimensions such as material selection, the status of the extruder, head, die, mold clamping mechanism and blowing system, and melt temperature, extrusion speed, blowing pressure and mold temperature.

1. Poor ultraviolet resistance of the resin.Material selection and handling are the foundation of forming quality.The 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 moisture content of raw materials, mixed impurities and improper regrind ratios will all cause various defects during processing. 2. No light stabilizer added.This factor causing the problem reflects that certain process conditions or material properties in extrusion '2079851475616104457 do not meet the optimal forming requirements.Such problems are often cumulative and concealed, and should be investigated and verified as key focus items during process debugging and finalization to ensure hidden dangers are eliminated at the source. In addition, the insufficient overall coordination of parison wall thickness control and parison temperature uniformity is also a factor that cannot be ignored; there are complex interactions and coupling relationships among the process parameters, and the deviation of any parameter may aggravate the degree of Discoloration and embrittlement of the product after ultraviolet irradiation through chain effects. In terms of equipment maintenance, the regular overhaul and accuracy confirmation of the extruder, head, die, mold clamping mechanism and blowing system 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 Discoloration and embrittlement of the product after ultraviolet irradiation problem.

1. Add UV absorber and light stabilizer.Formula and ratio adjustments should be determined on the basis of laboratory small-scale tests, and then verified by on-line pilot tests.Any change to the formula should be recorded and its impact on all aspects of product performance evaluated.Automatic metering and batching devices can effectively reduce manual batching errors and batch-to-batch fluctuations. 2. Select a weather-resistant resin grade.Before introducing new tools, new materials or new methods, sufficient applicability evaluation and small-batch verification should be carried out.It is recommended to first conduct offline tests or simulation analyses outside production conditions, and introduce them into the formal production line only after confirming effectiveness and safety.Keep proper change management records to facilitate subsequent traceability and experience accumulation. It is recommended to formulate a preventive checklist for the Discoloration and embrittlement of the product after ultraviolet irradiation problem, incorporate parison wall thickness control and parison temperature uniformity into the daily inspection scope, and conduct online monitoring of key parameters through the SPC statistical process control method to achieve early warning and rapid response to problems. In terms of material management, incoming inspection of raw materials and in-process testing of work-in-progress should be strengthened, and key performance indicators of HDPE, PP, PVC and PC should be strictly controlled to ensure the stability of forming quality from the source.

In summary, the causes of the "Discoloration and embrittlement of the product after ultraviolet irradiation" problem can be attributed to the combined action of multiple factors such as Poor ultraviolet resistance of the resin, No light stabilizer added.To solve this problem, it is necessary to start from aspects such as Add UV absorber and light stabilizer, Select a weather-resistant resin grade and take systematic governance measures.In actual production, it is recommended to establish a prevention and rapid response mechanism for this problem, achieving stable production and continuous improvement through parison wall thickness control and parison temperature uniformity.