Plastic bottles are mainly made of materials such as polyethylene or polypropylene with the addition of various organic solvents. Plastic bottle is widely used polyester (PET), polyethylene (PE), polypropylene (PP) as raw materials, after adding the corresponding organic solvents, after high temperature heating, through the plastic mold after blow molding, extrusion, or injection molding of plastic containers.
Plastic bottles are mainly used for beverage, food, cosmetics and other liquid or solid disposable plastic packaging containers. Plastic bottles have the characteristics of not easy to break, low cost and high transparency.
Common problems and solutions about cosmetic plastic bottle
In the design of extruded plastic bottles, if the material is high-density polyethylene or polypropylene, the cross-section of the plastic bottle should be rectangular or oval, for the material is low-density polyethylene or other flexible plastic bottles, its cross-section is better to be round. This makes it easy for the contents to be extruded from the plastic bottle. With the plastic bottle mouth with the use of plastic parts mainly for the cap and sealer. The design of the plastic bottle mouth should focus on how to make the plastic bottle mouth can be better with the cap and sealer with the bottom of the plastic bottle, is the weak part of the mechanical properties of the plastic bottle. Therefore, the bottom of the plastic bottle is generally designed into a concave shape; the corners of the plastic bottle, and the inner concave, are made larger arc over. In order to facilitate the stacking of plastic bottles and increase the stability of the stacking of plastic bottles, the bottom of plastic bottles should be designed with inner concave groove.
When the surface of plastic bottles is labeled, the labeling surface should be flat. A "frame" can be designed on the surface of the plastic bottle to make the label accurately positioned and not move. In the blow molding, the first contact part of the blowing of the billet, always tends to be the first hardened part. Therefore, the wall thickness of this part is also larger. The edges and corners are the last parts of the blow molded part, and the wall thickness of this part is smaller. 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 thin, increase the circumferential groove or convex rib on the surface of the plastic bottle, can improve the rigidity and bending resistance of the plastic bottle. Longitudinal grooves or reinforcement bars can eliminate the deflection, sagging or deformation of plastic bottles under long-term load.
The printing surface of the plastic bottle is the part where the consumer's attention is most focused. The printing surface should be flat and continuous; if the plastic bottle contains handles, grooves, reinforcing bars and other structures, care should be taken when designing not to cause inconvenience to the printing operation. Oval plastic bottle, stiffness is also higher, but the manufacturing cost of the mold is higher. Therefore, in order to ensure the stiffness of plastic bottles, in addition to choosing materials with high stiffness, the stiffness and load resistance strength of plastic bottles should be enhanced through the shape design of plastic bottles.
Since most plastics have notch sensitivity, plastic bottles are easy to produce cracks and cracks at the sharp corners, the root of the mouth thread, the neck and other parts, so these parts should be designed with rounded corners. For the rectangular plastic bottle at the forward, it needs to support most of the load of the plastic bottle, so locally increasing the wall thickness of this area is also beneficial to improve the stiffness and load resistance strength of the plastic bottle