During the production of beverages or household chemicals, airtight sealing is an essential requirement. Only in this way can a long shelf life of the contents be ensured without quality loss. Twist-off screw caps for bottles can provide this condition. They can be used for bottles of any volume, offering reliable protection against leakage and air ingress while being easy to open.
Where screw caps are used
Plastic caps with threads are widely used in various industries involved in liquid production or bottling. In particular, they are used for:
- packaging sauces and vegetable oils;
- bottling mineral or sparkling water, juices, soft drinks, kvass, beer;
- production of dairy products;
- manufacturing household chemicals.
They are used for bottles and large containers as well as jars, since they are produced in different sizes. Their wide popularity is due to the practicality of twist-off systems. Today, PET screw caps have virtually no equal alternative in terms of versatility, convenience, reliability, and affordability.
How the twist-off cap works
The main difference lies in the fixation method on the neck. Twist-off caps are screwed onto the threaded bottle neck. The thread is also applied to the cap edges. This sealing principle is convenient because pressure is evenly distributed around the entire circumference, ensuring tightness.
The connection mechanism is the same as that of screw caps for jars and is based on the following features:
- precise matching of thread turns on the preform and cap;
- tight contact with the neck edge during connection;
- rotational movement for secure sealing.
Additionally, for plastic containers, the “twist-off” principle also involves a tamper-evident ring. Its main function is to control opening. The ring breaks during the first twist of the cap.
Requirements for twist-off caps
The popularity of these systems in liquid production and bottling is due to their practicality. However, strict requirements are also imposed:
- geometry stability;
- uniform thickness and depth (to prevent defects during automated sealing);
- plasticity and resistance to pressure, temperature fluctuations, and direct sunlight.
Another important requirement is adaptability. Twist-off caps must comply with various neck standards used in PET preform production for plastic containers. Therefore, it is necessary to understand what systems exist.
Types of twist-off screw caps
The main distinguishing parameter is geometric accuracy, which must exactly match the neck. Therefore, screw caps are manufactured in strict compliance with standards. In particular, they are classified by diameter, edge height, and thread type. According to these indicators, the following twist-off cap sizes are distinguished:
- PCO 1880 – size with high edges (21 mm);
- PCO 1881 – lightweight version, depth 17 mm. The use of such systems allows material savings and reduces twist-off system cost, thereby increasing the profitability of products using this sealing;
- Bericap (38 mm) – this diameter is typical for containers used for dairy products and juices;
- 48 mm – size for large-volume bottles.
Twist-off caps for plastic containers are made from PET. This is a flexible and durable material resistant to loads and deformation. Thus, plastic screw caps possess the same properties, withstand high pressure, restore geometry after compression, and everyday external impacts do not reduce shape stability.
They are not used for resealing in industrial conditions, but in everyday use they are suitable for multiple opening and closing of bottles. This factor makes products in containers with twist-off systems popular and in demand among consumers, stimulating sales growth. As a result, the use of screw caps also contributes to increased business profitability.
In conclusion, the quality of PET sealing affects not only product preservation in plastic containers but also customer loyalty. Therefore, it is important to order twist-off systems from a manufacturer that follows production standards. We — the company “Preform Plant” — guarantee compliance of screw caps with current neck standards and manufacture them in a range of colors and sizes. You can order twist-off systems wholesale right now — leave a request and we will call back to уточнить details and delivery times.