Why do plastic pallets become brittle?

Views: 13     Author: Site Editor     Publish Time: 2022-04-20      Origin: Site

Why do plastic pallets become brittle?

The brittleness of the plastic pallet is a manifestation of the aging of the pallet. The aging of the plastic pallet will show the appearance of plastic discoloration, brittleness, simple cracking, etc. The aging of the pallet means that the macromolecular chain in the plastic is cracked, and the plastic will be dissolved. There are different components, some components of additives will react chemically or evaporate due to the effect of light, especially ultraviolet rays, some substances in the plastic pallet are changed, so that the original characteristics are lost, which constitutes the aging of the blue plastic and pallet become brittle.

Anti-Slip Heavy Duty Plastic Pallet

1. Plastic pallet mold

(1) If the gate is too small, you should consider adjusting the size of the gate or adding an auxiliary gate.

(2) If the shunt channel is too small or improperly equipped, it should be arranged as balanced and reasonable as possible or the size of the shunt channel should be added.

(3) Poor mold structure causes an abnormal injection cycle.

2. Plastic pallet equipment

(1) There are dead corners or obstacles in the barrel, which simply promotes the degradation of the melt.

(2) The plasticizing capacity of the machine is too small, and the plastic is not sufficiently plasticized in the barrel; the plasticizing capacity of the machine is too large, the time for the plastic to be heated and sheared in the barrel is too long, and the plastic is simply aged, making the finished product change crisp.

(3) The ejector equipment is skewed or unbalanced, and the top stem has a small cross-sectional area or improper distribution.

Anti-Slip Heavy Duty Plastic Pallet

3. Material aspects of plastic pallets

(1) When the material is mixed with other impurities or doped with inappropriate or excessive solvent or other additives.

(2) Some plastics such as ABS, etc., will react with water vapor when heated under damp conditions, which will cause large strain on the parts.

(3) Too many times of plastic regeneration or too high content of recycled materials, or too long heating time in the barrel, will cause the parts to be brittle.

(4) The quality of the plastic itself is not good, for example, the molecular weight distribution is large, and the proportion of components with uneven structures such as rigid molecular chains is too large; or it is contaminated by other plastics, bad additives, dust, and impurities. reason.

4. Technical aspects of plastic pallets

(1) The temperature of the barrel and nozzle is too low, increase it. If the material is easily degraded, the temperature of the barrel and nozzle should be increased.

(2) Decrease the pre-plastic backpressure and rotation speed of the screw to make the material slightly loose and reduce the degradation of plastic due to shear overheating.

(3) If the mold temperature is too high, demolding is difficult; if the mold temperature is too low, the plastic cools prematurely, the fusion seam is poorly blended, and it is easy to crack, especially for high melting point plastics such as polycarbonate.

(4) The cavity core must have an appropriate draft slope. When the core is difficult to demould, the cavity temperature should be increased and the cooling time should be shortened; when the cavity is difficult to demould, the cavity temperature should be lowered and the cooling time should be extended.

(5) Minimize the use of metal inserts, such as brittle plastics with a large specific volume of cold and heat, such as polystyrene, and can not be added to insert injection molding.

    

 

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