Problems With Plastic Bottles

(1) When designing extruded plastic bottles, if the material is high-density polyethylene or polypropylene, the cross-section of the plastic bottle should be rectangular or oval, and for low-density polyethylene or other flexible plastic bottles, its cross-section is round. This makes it easier for the contents to be squeezed out of the plastic bottle. The plastic parts used with the plastic bottle mouth are mainly the bottle cap and sealer. The design of the plastic bottle mouth should focus on how to make the plastic bottle mouth better fit with the cap and sealer. The bottom of the plastic bottle is the weak part of the mechanical properties of the plastic bottle. Therefore, the bottom of plastic bottles is generally designed to be concave; The corners and inner recesses of the plastic bottle are made of large arc excesses. In order to facilitate the stacking of plastic bottles and increase the stacking stability of plastic bottles, the bottom of plastic bottles should be designed with internal grooves.
(2) When the surface of the plastic bottle is labeled, the surface of the label should be flat. A "frame" can be designed on the surface of the plastic bottle so that the label is accurately positioned without moving. In blow molding, the part where the billet blows first touches always tends to harden first. Therefore, the wall thickness of this part is also larger. The edge and corner part is the last contact between the billet inflation, and the wall thickness of this part is small. Therefore, the edges and corners of plastic bottles should be designed with rounded corners. Change the surface shape of the plastic bottle, such as the middle of the plastic bottle is relatively thinner, increase the circumferential groove or convex rib on the surface of the plastic bottle, which can improve the rigidity and bending resistance of the plastic bottle. Longitudinal grooves or stiffeners eliminate shifting, sagging or deformation of plastic bottles under long-term loads.

(3) The printing side of plastic bottles is the part where consumers pay the most attention. The printing surface should be flat and continuous; If the plastic bottle contains handles, grooves, stiffeners and other structures, care should be taken not to cause inconvenience to the printing operation. Oval plastic bottles, rigidity is also higher, but the manufacturing cost of the mold is higher. Therefore, in order to ensure the rigidity of plastic bottles, in addition to selecting materials with high rigidity, it is also necessary to enhance the stiffness and load strength of plastic bottles through the shape design of plastic bottles.
(4) Since most plastics have notch sensitivity, plastic bottles are prone to cracks and cracks at sharp corners, roots of mouth threads, necks and other parts, so these parts should be designed with rounded corners. For the transfer of rectangular plastic bottles, it is necessary to support most of the load of plastic bottles, so increasing the wall thickness at this place is also conducive to improving the stiffness and load strength of plastic bottles.