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Cap Liners 101

4 November 2023 Posted by: makeyourmark Uncategorized

What are cap liners?

Welcome to Cap Liners 101. Cap liners, often referred to as bottle or container liners, are sealing materials placed inside the caps of containers, such as bottles, jars, or other types of packaging. Cap liners are essential for various industries, including food and beverage, pharmaceuticals, cosmetics, chemicals, and more, to ensure product quality, safety, and longevity. 

What are cap liners used for?

Next in Cap Liners 101: Cap liners are used for a variety of purposes across different industries to ensure the integrity and safety of products in containers with caps. Some common uses for cap liners are:

  • Sealing: Cap liners create a tight seal when the cap is applied to the container. This seal helps prevent the contents from leaking, spilling, or evaporating, and it also protects the product from external contaminants like dust, moisture, or air. This is especially important for products that need to maintain freshness or integrity.
  • Tamper-Evident: Some cap liners are designed to provide tamper-evident protection. When the container is initially opened, the liner may break or show signs of tampering, alerting consumers to the possibility that the product may have been compromised.
  • Safety and Hygiene: Cap liners can help maintain the hygiene and safety of products. They act as a barrier that separates the product from the outer environment, reducing the risk of contamination.
  • Preservation: In some cases, cap liners are used to preserve the quality and shelf life of products. For example, in the food and pharmaceutical industries, moisture- or oxygen-absorbing liners may be used to prevent spoilage or degradation.

What are they made of?

Cap Liners 101 continued: The kind of cap liner material depends on factors such as the type of product, the required level of sealing, tamper-evident features, chemical compatibility, and moisture or gas barrier properties. Different industries and applications may require specific cap liner materials to meet their unique packaging and product protection needs. Most cap liner materials will fall under these categories:

  • Polyethylene or polyurethane foam: Foam liners are used for products that require a cushioned seal, such as cosmetics, lotions, and some chemicals.
  • Paperboard: These liners are commonly used for products like dry food items or consumer goods.
  • Plastic: Plastic cap liners can be made from various plastic materials, including polyethylene, polypropylene, or PVC (polyvinyl chloride). Plastic liners are often used for products that require a moisture-resistant or chemical-resistant seal. They are versatile and can be used in a wide range of industries.
  • Foil: They are commonly used for products that require a strong, tamper-evident seal and protection from external elements. Induction sealing, a method that involves heat and pressure, is often used to bond foil liners to containers. See the ILT product catalog for a full list of cap liners.
  • Wax: They are often used for items like glass jars containing jams, jellies, or other preserved foods.
  • Rubber or Elastomeric Materials: These liners are often used for products that require a secure and airtight seal, such as chemicals or pharmaceuticals.

How Are They Made?

Last, but not least, in Cap Liners 101: Cap liners are typically produced through a multi-step manufacturing process. First, appropriate materials are chosen based on the liner’s intended use. For liners that require adhesion, an adhesive or coating is applied to one side of the liner material. ILT manufactures a “bonded” seal, which does not need to use adhesive that can compromise the integrity of the sample in the container. Rigorous quality control measures are employed to guarantee consistency and compliance with specifications. The finished cap liners are then packaged and distributed to manufacturers or packaging companies in rolls or stacks, ready for use in sealing containers and safeguarding the integrity of various products.

Read more about the seals and septa industry on our blog page or learn more about ILT, the world leader in manufacturing seals and septa here.