What is a Shrink Wrap?

Effective moisture control is critical in packaging to ensure product integrity, longevity, and performance. Moisture—whether from external environments or intrinsic to the product itself—can lead to issues such as corrosion, mold growth, and product degradation.

Shrink wrap provides a tight, protective seal that conforms to the product’s shape, offering a barrier against external contaminants and physical damage. However, while shrink wrap is excellent for creating a physical barrier, it is not inherently moisture-absorbent. This is where desiccants come into play. Desiccants are materials designed to absorb moisture from the air, trap it, and thus maintain a dry environment within the packaging.

The integration of shrink wrap and desiccants offers a comprehensive packaging solution that combines the strength and versatility of shrink wrap with the moisture-absorbing capabilities of desiccants. This dual approach not only enhances the physical protection of products but also actively manages the internal atmosphere of the packaging.

Common Moisture-Related Issues

Moisture control in packaging is crucial because unmanaged moisture can harm stored or transported goods. Common issues include:

• Corrosion and Rust: Metal components are susceptible to moisture-induced corrosion and rust, compromising structural integrity and functionality.
• Mold and Fungus Growth: When exposed to moisture, organic materials such as food, textiles, and paper products can become breeding grounds for mold and fungi, posing health risks and reducing product quality.
• Clumping and Caking: Products like powdered goods can absorb moisture and form clumps, making them unusable and leading to significant product waste.
• Delamination and Peeling: In layered materials, such as electronics or laminates, moisture can cause layers to separate (delaminate), compromising the product’s structural integrity.
• Degradation of Product Efficacy: Moisture can alter the chemical stability of pharmaceuticals, reducing their effectiveness and shelf life.

Impact of Moisture on Different Types of Products

The impact of moisture is not limited to a specific category but spans across various industries:

• Electronics: Moisture can cause short circuits and corrosion of components, leading to failures and reducing the lifespan of electronic devices.
• Pharmaceuticals: Moisture is a critical factor in pharmaceuticals as it can lead to chemical degradation or physical alteration of drugs, impacting their therapeutic effects and safety.
• Food Products: Excess moisture in food can lead to microbial growth, spoilage, and changes in texture and taste, affecting consumer safety and product appeal.
• Textiles: Moisture can cause staining, promote mildew growth, and deteriorate fabric integrity, impacting the quality and durability of textile products.
• Consumer Goods: From cosmetics to books, moisture can compromise packaging and the product, decreasing consumer satisfaction and increasing returns.

Understanding Shrink Wrap and Desiccants

What is Shrink Wrap? Shrink wrap is a polymer plastic film that, when heated, tightly conforms to the shape of the object it is covering. This material is chosen for its ability to create a strong, tamper-evident seal that protects against dust, dirt, and moisture from external sources.

Commonly used materials for shrink wrap include polyolefin, PVC (polyvinyl chloride), and polyethylene, each offering different levels of durability, clarity, and shrink ratio. Shrink wrap’s applications are vast, ranging from the packaging of individual food items to bundling larger items like pharmaceuticals and electronics, where protection during transport and storage is crucial.

What are Desiccants?: Desiccants induce or sustain a state of dryness in their vicinity; they actively absorb moisture from the air, thereby controlling the humidity within a closed environment. The most familiar desiccant is silica gel, recognized by its presence in small sachets used to protect a variety of products, including electronics and leather goods.

Other types of desiccants include molecular sieves, often used for more rigorous applications in the pharmaceutical industry, and calcium chloride, known for its high moisture absorption capacity. Desiccants work by adsorption or chemical reactions that trap water vapor, effectively preventing moisture-related deterioration over time.

Integration Techniques

Integrating shrink wrap and desiccants effectively requires strategic methods to maximize the benefits of both materials. The integration can be implemented in several ways:

• Desiccant Inserts: Desiccants can be included inside products like individual sachets or strips or even incorporated directly into the packaging. This method is often used for pharmaceuticals and electronics, where direct placement ensures proximity to moisture-sensitive areas.
• Desiccant-embedded Films: Some shrink wraps have desiccants embedded within the film itself. This innovative approach provides an even distribution of moisture absorption across the entire package, enhancing protection without additional insertion processes.
• Layered Packaging: In this method, desiccants are placed between layers of shrink wrap, particularly for larger items or pallets. This technique ensures that moisture trapped during sealing can be absorbed effectively, protecting the product from within the sealed environment.

Placement and Proportioning

The effectiveness of desiccants in moisture control depends significantly on their proper placement and quantity within the packaging. Key considerations include:

• Placement: Desiccants should be placed where they can interact most with air inside the package. For example, placing desiccants near air pockets within the shrink wrap can enhance their efficacy as these areas will likely trap moisture.
• Proportioning: The amount of desiccant needed depends on several factors, such as the type of product, the volume of air within the packaging, the expected storage conditions, and the duration of storage or transport. Calculations often involve using specific formulas or guidelines provided by desiccant manufacturers to determine the optimal quantity required to maintain dry conditions.
• Accessibility and Safety: When placing desiccants, it is also crucial to consider their accessibility for removal or replacement and their safety in terms of chemical interaction with the product. For consumer products, it’s important to ensure that desiccants are not easily accessible to end users, especially children, and are clearly labeled as not edible.

By combining shrink wrap and desiccants and considering their strategic placement and proportioning, businesses can greatly enhance the protective qualities of their packaging, ensuring that products remain dry, stable, and free from moisture-related damages throughout their lifecycle.

Material Selection and Properties

When integrating shrink wrap and desiccants into a packaging solution, it’s crucial to consider these material properties and how they interact with the product and environmental conditions.

This selection and combination ensure optimal moisture control, safeguarding the quality and longevity of the product throughout its lifecycle. Below is a table that contrasts the properties, applications, and environmental impacts of different types of shrink wraps and desiccants, highlighting how each material suits different packaging needs.

Criteria	Polyolefin	PVC	Polyethylene	Silica Gel	Molecular Sieve	Calcium Chloride
Applications	Food products	Non-food items	Heavier industrial items	Wide range of products (electronics, pharmaceuticals)	Sensitive medical and electronic equipment	Extremely humid conditions
Properties	FDA-approved, excellent clarity & strength	Excellent clarity, good shrink properties	Thicker, durable, suitable for heavier loads	Absorbs up to 40% of its weight in moisture	Very high moisture absorption at low humidity levels	Aggressive moisture absorption can liquefy upon saturation
Environmental Impact	More environmentally friendly	Releases hydrogen chloride during heating	Durable, often used for bundling	Non-reactive, non-toxic	Non-toxic, but expensive and complex to produce	Requires careful handling due to potential liquefaction
Moisture Barrier	Low permeability	Low permeability	Low permeability, thicker barrier	High absorption capacity	Extremely effective at moisture control	High capacity, suitable for very humid conditions
Seal Integrity	Strong, durable seals	Good sealing ability	Best for strong, durable seals	N/A	N/A	N/A

Optimizing the Amount of Desiccant

The effectiveness of desiccants in controlling moisture within a package largely depends on their proper quantification. Here are some guidelines to optimize the amount of desiccant used:

• Calculate the Volume: Start by calculating the total air volume within the packaged product that needs to be kept dry. This includes considering both the product size and the packaging.
• Assess the Moisture Load: Determine the potential moisture sources, including the product itself, the packaging materials, and the external environment during shipping and storage.
• Use Desiccant Formulas: Desiccant bag manufacturers often provide formulas or guidelines based on the type of desiccant, the package volume, product type, and expected conditions. These formulas can help determine the appropriate amount of desiccant needed.
• Consider Shelf Life and Storage Conditions: Factor in the expected shelf life and storage conditions. More desiccant may be required for longer storage periods or in more humid climates.
• Regular Testing: It’s crucial to regularly test the effectiveness of the desiccant amount used and make adjustments as necessary. This could involve trial and error with initial batch shipments or during a change in storage conditions.

Sealing Techniques for Maximum Effectiveness

Proper sealing techniques are crucial to maintain the integrity of shrink-wrapped packages, ensuring that moisture does not enter or accumulate:

• Ensure Proper Equipment Calibration: Regular maintenance and calibration of heat-sealing equipment ensure consistent and effective seals.
• Opt for High-Quality Shrink Wrap: Use high-quality shrink wrap compatible with your product and sealing equipment. The right material can withstand the heat and pressure of sealing without degrading.
• Monitor Seal Temperature and Speed: Adjust the temperature and speed of the sealing process to match the thickness and type of shrink wrap. Incorrect settings can lead to weak seals or damage to the wrap.
• Test Seal Integrity: Implement quality control measures to check the integrity of seals regularly. This can include visual inspections, pressure tests, or even dye penetration tests for critical applications.
• Eliminate Contaminants: Ensure that the sealing area is free from dust, moisture, and other contaminants that can interfere with the seal’s effectiveness.

Conclusion

Effective moisture control in packaging is not just about maintaining the aesthetic integrity of products but is crucial for ensuring their functionality, longevity, and safety. By selecting the appropriate materials and applying the best practices in sealing and desiccant use; companies can enhance the durability and shelf life of their products, ultimately leading to improved customer satisfaction and reduced product returns.

As a global supplier and manufacturer of desiccant packs, Stream Peak International holds ISO 9001 and 14001 certifications, affirming its adherence to international standards in quality management and environmental responsibility. The company’s dedicated Quality Assurance (QA) lab plays a role in product innovation and quality control. By focusing on reducing waste, Stream Peak International ensures the effectiveness of its desiccant solutions and aligns with broader environmental goals.