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The Composition of Clear PET Plastic Jars with CR Cap: A Detailed Overview


Clear PET plastic jars with CR (child-resistant) caps are widely used across various industries for their durability, transparency, and safety features. Understanding the materials used in these jars and caps is crucial for appreciating their benefits and applications. In this blog, we'll delve into the materials that make up clear PET plastic jars with CR caps, highlighting their properties and advantages.

What is PET Plastic?

Polyethylene Terephthalate (PET) is the primary material used in manufacturing clear plastic jars. PET is a type of polyester that is:

- Durable and Lightweight: PET is known for its high strength-to-weight ratio, making it a robust yet lightweight material suitable for packaging.

- Transparent: PET plastic is highly transparent, allowing consumers to see the contents of the jar clearly.

- Chemical Resistant: PET is resistant to various chemicals, ensuring that the stored products do not react with the packaging.

- Recyclable: PET is one of the most recycled plastics, contributing to environmental sustainability.

How are PET Plastic Jars Manufactured?

The process of making PET plastic jars involves several steps:

1. Injection Molding: PET resin is melted and injected into a mold to create a preform, which resembles a test tube with a threaded neck.

2. Blow Molding: The preform is heated and placed into a mold where it is blown into the shape of the final jar. This process allows for creating jars of various sizes and shapes while maintaining the clarity and strength of the PET material.

What is a CR Cap?

A CR (child-resistant) cap is designed to prevent children from easily opening the jar, ensuring the safety of the contents. These caps are typically made from materials that provide both durability and tamper resistance.

Materials Used in CR Caps

CR caps are usually made from a combination of the following materials:

1. Polypropylene (PP): Polypropylene is a common material used in CR caps due to its:

  - Durability: PP is tough and can withstand repeated use without losing its shape.

  - Chemical Resistance: Like PET, PP is resistant to many chemicals, ensuring the safety and integrity of the stored products.

  - Flexibility: PP provides the flexibility needed for the child-resistant mechanisms to function effectively.

2. Polyethylene (PE): Another material often used in CR caps is polyethylene, known for its:

  - Impact Resistance: PE can absorb impacts without breaking, adding to the durability of the cap.

  - Ease of Processing: PE is easy to mold and shape, making it suitable for complex designs required in CR caps.

3. Rubber or Silicone: Some CR caps incorporate rubber or silicone components to provide a better seal and enhance the child-resistant mechanism.

How Do CR Caps Work?

CR caps typically employ one or more mechanisms to prevent children from opening them easily:

- Push-and-Turn: This common design requires the user to push down on the cap while simultaneously turning it, making it difficult for children to open but easy for adults.

- Squeeze-and-Turn: Another design involves squeezing the sides of the cap while turning it, adding an extra layer of difficulty for children.

Advantages of Using PET Plastic Jars with CR Caps

The combination of clear PET plastic jars and CR caps offers several advantages:

- Safety: The child-resistant feature ensures that hazardous or sensitive contents are kept out of reach of children.

- Transparency: The clear PET material allows consumers to see the contents, enhancing product visibility and appeal.

- Durability: Both PET jars and CR caps are designed to be strong and resistant to damage, ensuring the longevity of the packaging.

- Versatility: These jars and caps can be used for a wide range of products, from pharmaceuticals and cosmetics to food and household items.


Clear PET plastic jars with CR caps are a testament to modern packaging innovation, combining safety, durability, and visibility. The use of PET plastic for the jars and materials like polypropylene and polyethylene for the CR caps ensures that these packaging solutions meet the highest standards of quality and functionality. Whether you're storing medications, food products, or household items, clear PET plastic jars with CR caps provide a reliable and attractive option.

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