A plastic cap with unfamiliar symbols often raises questions among consumers, manufacturers, and even recyclers. These small icons provide important information about the composition, properties, and recyclability of the product. So why is plastic cap labeling important today? It’s a matter of safety, environmental friendliness, and compatibility with various types of containers. Proper interpretation of the symbols helps avoid mistakes when choosing packaging materials and ensures appropriate waste management.
Contents
Why plastic cap markings are important
Marking solves several important tasks. It informs about the chemical composition of the product, which directly affects the safety of contact with food. Some types of plastic are only suitable for specific contents.
Markings on plastic caps help packaging manufacturers choose compatible materials. Each plastic type has unique properties: heat resistance, strength, gas permeability. Incompatibility between cap and bottle may lead to leakage or reduced shelf life.
Recycling becomes more efficient with clear material identification. Waste sorting is simplified when the product has proper labeling. Recyclable plastic is easier to separate from non-recyclable, reducing environmental pollution.
Types of markings on caps
The international polymer labeling system includes numbers from 1 to 7 inside a triangle of arrows (recycling symbol). But what do these numbers mean on bottle caps? They indicate the type of polymer used:
- 1 – PET/PETE (Polyethylene Terephthalate) – often used for clear water and beverage bottles.
- 2 – HDPE (High-Density Polyethylene) – the main material for most plastic caps.
- 3 – PVC (Polyvinyl Chloride) – rarely used for caps due to poor chemical resistance.
- 4 – LDPE (Low-Density Polyethylene) – used for soft sealing caps.
- 5 – PP (Polypropylene) – popular for its heat resistance.
- 6 – PS (Polystyrene) – rarely used due to brittleness.
- 7 – OTHER – includes composite or non-standard plastics.
Letter abbreviations on caps
Such marking often duplicates the numeric code, providing more detail about the material. Here’s what the letter codes on plastic caps mean:
- HDPE - High Density Polyethylene (Polyethylene) is resistant to chemical impacts and has good barrier properties against moisture. Caps made from this material are rigid, opaque, and provide reliable sealing.
- PP - Polypropylene (Polypropylene) withstands high temperatures up to 100°C, which is why it is used for hot filling and products requiring pasteurization. Bottle caps made from this material are durable and chemically inert.
- PET/PETE - Polyethylene Terephthalate (Polyethylene Terephthalate) has high transparency and gas barrier properties. Caps with this marking are less common than bottles made from this material.
- LDPE - Low Density Polyethylene (Low Density Polyethylene) is more flexible and soft. It is used for seals and protective caps.
- PVC - Polyvinyl Chloride (Polyvinyl Chloride) is characterized by high strength and low gas permeability. Its use for food packaging is limited due to the potential risks of releasing chlorine-containing compounds.
- PS - Polystyrene (Polystyrene) is a transparent, rigid material. It is rarely used due to its brittleness.
- OTHER/O - indicates mixed, multilayer materials, biopolymers, and other types of plastic not included in the main classification.
Additional cap markings
In addition to polymer type, caps often have other important markings.
For example, PCO 1881 indicates compatibility with a certain bottle neck standard. It's widely used for carbonated drinks and defines:
- ◾️ thread pitch;
- ◾️ height;
- ◾️ diameter.
Numeric and letter markings are supported by standard references (e.g., GOST or ISO), confirming compliance and safety.
Manufacturing details often include date, batch number, and production line – important for quality control and traceability.
Brand logos help with identification and protection against counterfeiting. Color coding is also common to help sort by content type:
- ◾️ water;
- ◾️ milk;
- ◾️ oil.
Clear labeling promotes responsible recycling. Consumers get information about recyclability and proper disposal. Manufacturers show environmental awareness and support waste sorting.
Our modern plastic products factory fully complies with national and international labeling standards. This helps to:
- ◾️ build consumer trust;
- ◾️ streamline logistics;
- ◾️ ensure proper disposal of used packaging.
Understanding polymer labeling enables smart choices for safe and eco-friendly materials. Every symbol on a plastic cap carries important information impacting both health and the environment.