The Quality Control and Testing of Plastic Bottles

The formulation and testing of the standard for the function of the bottle is the core of the whole bottle quality control. The direct reflection is whether the bottle meets the use requirements.

In general, the quality control and testing of injection blown and injection drawn blown bottles in terms of functionality may involve the following items according to the use requirements of their products:

1. Mating performance
Ensure the smooth cooperation between bottle and lid, to meet the machine and other use requirements, the general bottle and lid (or pump head) cooperation mode is mainly screw structure or buckle structure. There are specific requirements for bottle cap torsion with different diameter thread structure. Buckle structure in order to ensure that the lid meets the requirements of the use of the cap, the cap with the pressure, open the cap force and pull the cap force can be tested, which are related to the bottle structure and size.

2. sealing performance
Because the injection and injection pull blowing bottle mouth size precision is high and stable. It is widely used in food, medicine and cosmetic packaging with sealing requirements. In addition to the use of various forms of gaskets to ensure the sealing, for direct sealing design of the bottle, the sealing performance of the bottle should be controlled and tested.

There are two main ways of sealing test: vacuuming test or irrigation static test. There are standard requirements for pharmaceutical bottle testing, vacuumizing test is basically adopted, and there are clear requirements for vacuumizing methods, conditions and capping force, etc. For details, please refer to the national standards for drug bottle sealing test. Appropriate sealing performance monitoring methods are developed for food and cosmetic bottles considering contents characteristics, cap structure and use environment. High sealing requirements can be used to install content or water vacuuming test, general requirements can be used to install content or water standing, the time can be set according to the actual needs.

It should be emphasized that the sealing effect can be achieved by different bottle caps with different structures and materials, so it must be considered at the beginning of design. For general requirements, small diameter threaded structure can achieve sealing requirements. Higher requirements or installation of relatively strong diffused content, can consider the thread matching structure and gasket auxiliary seal. For low requirements, such as solid candy is not easy to absorb moisture, can use large diameter or buckle with the structure.

3. Impact resistance or drop resistance
In order to prevent the bottle from breaking or the cap from breaking due to the bottle drop during the product shelf, transportation and use, the impact resistance of the cap can be monitored and tested. The test can be set as required. Can be loaded with contents or water, at a certain height, free (or directional) drop on the hard ground or plane, check its integrity. For products with special requirements, such as the use of low temperature environment, especially PP material bottles, samples can be frozen after dropping, testing its performance. Drop performance and bottle material, thickness, tensile ratio, bottle structure are related to the drop requirements of the product. The design needs to consider the choice of materials in advance, the injection and blow bottle needs to design reasonable wall thickness, tensile ratio, bottle bottom structure and bottle body reinforcement and other problems.

4. Other functional tests
For bottles with special use requirements, test items can be designed according to needs. For example, in order to meet the requirements of storage and transportation or routing gland, the pressure resistance of bottles can be designed and tested.