Increased acetaldehyde content of the bottle after long-term storage

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Increased acetaldehyde content of the bottle after long-term storage".The specific manifestation is The acetaldehyde content in the bottle exceeds the standard, affecting food safety.This defect is more common when processing materials such as PET, PP and PC, and its occurrence is usually related to unreasonable settings of stretching temperature, stretch ratio, blowing pressure and preform heating uniformity.When the Increased acetaldehyde content of the bottle after long-term storage 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 stretch '2079851475616104457 machine, heating oven, stretch rod and blow mold, and stretching temperature, stretch ratio, blowing pressure and preform heating uniformity.

1. PET thermal degradation produces acetaldehyde.Resin undergoes thermal degradation, oxidative degradation and mechanochemical degradation under high temperature and shear, leading to molecular chain scission, reduced molecular weight and deteriorated mechanical properties.Controlling processing temperature within the safe window, shortening melt heat history time and adding appropriate heat stabilizers and antioxidants are effective means to inhibit degradation. 2. Storage temperature too high.Temperature is the core factor affecting melt fluidity and viscosity.Excessively high temperature settings will cause decreased melt viscosity, insufficient melt strength and even thermal degradation; excessively low temperature results in poor melt fluidity and insufficient plasticization, making smooth filling or forming impossible.A reasonable temperature window should be optimally determined within the recommended range according to the melting characteristics and thermal stability of the material. In addition, the insufficient overall coordination of preform heating uniformity and biaxial stretch orientation control 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 Increased acetaldehyde content of the bottle after long-term storage through chain effects. In terms of equipment maintenance, the regular overhaul and accuracy confirmation of the stretch '2079851475616104457 machine, heating oven, stretch rod and blow mold 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 Increased acetaldehyde content of the bottle after long-term storage problem.

1. Lower the processing temperature to reduce acetaldehyde generation.Adjustments should follow the principle of gradual progress; each adjustment should not be too large, and a decrement of 5%~15% of the current value is recommended.After each adjustment, stably observe the product quality changes for at least 5~10 mold cycles, and continue adjusting only after confirming the improvement direction is correct; never make excessive one-step adjustments. 2. Store preforms at low temperature.The storage conditions of materials and products directly affect their processing adaptability and use performance.The temperature, humidity and lighting conditions of the storage environment should be controlled according to material characteristics, avoiding high-temperature high-humidity and direct sunlight areas.For hygroscopic materials, sealed moisture-proof packaging or dry environment storage should be adopted. It is recommended to formulate a preventive checklist for the Increased acetaldehyde content of the bottle after long-term storage problem, incorporate preform heating uniformity and biaxial stretch orientation control 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 PET, PP and PC should be strictly controlled to ensure the stability of forming quality from the source.

In summary, the causes of the "Increased acetaldehyde content of the bottle after long-term storage" problem can be attributed to the combined action of multiple factors such as PET thermal degradation produces acetaldehyde, Storage temperature too high.To solve this problem, it is necessary to start from aspects such as Lower the processing temperature to reduce acetaldehyde generation, Store preforms at low temperature 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 preform heating uniformity and biaxial stretch orientation control.