Contents
A cap is a necessary element that closes the neck of a bottle. This is a high-tech product that determines the tightness of the packaging, the safety of the product, and the convenience for the end consumer. To understand how plastic caps are made, you need to consider the entire process: from the selection of raw materials, standards to the final quality control on an automated line. At the Preform Plant, this process is fine-tuned to the smallest detail, which allows us to produce millions of products with consistently high quality.
What are lids made of: choosing a material
The choice of polymer directly affects the performance characteristics of the cap. The material must match the type of product that will be stored in the bottle, withstand loads during transportation, use. Most often, two types of plastic are used in production.
- Polyethylene (PE/PE). This is an elastic, durable material that is resistant to cracking. It is ideal for sealing bottles with still water, juices, dairy products and household chemicals. Polyethylene provides a tight fit to the neck, creating a reliable barrier.
- Polypropylene (PP). A more rigid, heat-resistant polymer. It is chosen for carbonated drinks, as it can withstand internal pressure better. Polypropylene is also resistant to oils and some chemical compounds, which makes it suitable for specific products.
Neck Standards: Guarantee of Compatibility
To caps for plastic bottles perfectly fit the container, they are produced in strict accordance with international and national neck standards. These are unified parameters that guarantee that plastic containers from one manufacturer will be compatible with closures from another.
There are many standards on the market, each designed for a specific type of product. For example, the PCO 1881 standard is used for PET bottles with carbonated drinks, BPF is used for large containers with a volume of 5-10 liters, and 38 mm is used for juices and dairy products. "Preform Plant" produces closures for all common standards, which allows our customers to select components for any production task.
Why is food grade plastic used?
When it comes to food and beverage packaging, safety is paramount. Food grade plastic is a polymer that has been certified and deemed safe for contact with food. It is chemically inert, meaning it does not react with the contents of the bottle, does not emit harmful substances, and does not change the taste or smell of the product.
Our company has implemented the ISO 22000 food safety management system. This means that we control the entire chain: from purchasing certified raw materials from trusted suppliers from Europe and Asia to testing finished products in our own laboratory. Each batch of products is tested for compliance with sanitary and epidemiological standards.
Production stages: from granules to finished products
Modern technology for manufacturing lids is a fully automated process that takes place on high-performance equipment. At the Preform Plant, lid manufacturing equipment from world leaders such as ENGEL is used for this purpose. The entire cycle can be divided into several key stages.
- Preparation of raw materials. Polyethylene or polypropylene granules are loaded into a special bin, where they are dried to remove excess moisture. At this stage, dye is added if it is necessary to produce lids of a certain color.
- Injection molding. This is the main stage that explains how plastic caps are made. Prepared raw materials are melted and injected into a mold under high pressure. A mold is a complex tool that determines the geometry, threads, and all structural elements of the future product with micron precision.
- Cooling and extraction. After filling the mold, the plastic is quickly cooled by water circulating through special channels. The cooling time is strictly controlled, as the final properties and dimensions of the lid depend on it. Then the finished products are automatically removed from the mold.
- Control and post-processing. At the final stage of cap production, visual and instrumental quality control takes place. For tamper-evident caps, a special machine makes cuts on the safety ring. After that, the finished product is packed in boxes for shipment to the customer.
The entire process, from loading granules to packaging, takes a matter of seconds, with minimal human involvement, which eliminates errors and guarantees the stability of each batch.
Our plant offers comprehensive solutions for beverage and liquid product manufacturers. In addition to caps, we produce preforms and PET bottle handles. To get advice on the selection of components and request a commercial offer, contact our sales department.