Shrink Film: How to Avoid Sealing and Shrinking Failures in Industrial Packaging

1. Understanding Industrial Adhesives

Industrial adhesives are engineered compounds that join materials by forming a strong and durable bond through chemical or physical interaction. They are used across a wide range of industries — from automotive and electronics to packaging and woodworking — replacing mechanical fasteners such as screws, rivets, and welds.

Unlike consumer-grade glues, industrial adhesives are formulated to meet precise technical requirements such as:

• High tensile and shear strength

• Heat, moisture, or chemical resistance

• Controlled viscosity and open time

• Compatibility with substrates like metal, plastic, glass, and composites

By distributing stress evenly across the bonded area, adhesives can create lighter, cleaner, and more efficient assemblies.

2. The Main Types of Industrial Adhesives

Choosing the right adhesive starts with understanding the chemistry behind it. Each type offers a unique balance between speed, strength, flexibility, and temperature resistance.

2.1. Hot Melt Adhesives (EVA, Polyolefin, and Polyamide)

Hot melts are thermoplastic adhesives that are solid at room temperature and liquefy when heated. They set rapidly upon cooling, making them ideal for high-speed packaging lines and automated applications.

• EVA (Ethylene Vinyl Acetate): The most common hot melt formulation, offering excellent adhesion to paper, cardboard, and some plastics. It provides a good balance of bond strength and open time.

• Metallocene and Polyolefin Hot Melts: Known for their superior thermal stability and clean-running performance. They reduce char formation in equipment and improve efficiency.

• Polyamide Hot Melts: Offer high temperature and chemical resistance, ideal for demanding environments such as electronics and automotive components.

Key advantages: Fast set time, easy handling, and low equipment maintenance.

Limitations: Poor performance under continuous high temperatures or with certain plastics.

2.2. Reactive Adhesives (Polyurethane, Epoxy, Cyanoacrylate)

Reactive adhesives cure through chemical reactions, forming crosslinked bonds with exceptional strength and durability.

• Polyurethane (PU): Flexible, impact-resistant, and excellent for bonding dissimilar materials. Common in wood, automotive, and composite bonding.

• Epoxy: Delivers outstanding strength, chemical resistance, and dimensional stability — suitable for structural bonding and metal assemblies.

• Cyanoacrylate (Instant Adhesive): Cures within seconds upon contact with moisture, ideal for small assemblies and quick repairs.

Key advantages: High structural strength, chemical resistance, and durability.

Limitations: Longer cure times (except cyanoacrylate) and higher material cost.

2.3. Pressure-Sensitive Adhesives (PSA)

Used in tapes, labels, and films, PSAs form an instant bond under light pressure without requiring heat or solvent. They are commonly acrylic or rubber-based and can be formulated for removable or permanent adhesion.

Key advantages: Clean application, flexibility, and reworkability.

Limitations: Not suitable for structural loads or high-temperature environments.

2.4. Water-Based and Solvent-Based Adhesives

These are liquid formulations where the polymer is dispersed or dissolved in a carrier. Once applied, the carrier evaporates, leaving a solid film that forms the bond.

• Water-Based Adhesives: Eco-friendly, safe, and cost-effective, often used in paper converting, woodworking, and packaging.

• Solvent-Based Adhesives: Provide faster tack and stronger bonds on non-porous substrates but require proper ventilation and safety measures.

Key advantages: Excellent control over viscosity and spread.

Limitations: Slower drying time (water-based) or volatile emissions (solvent-based).

3. Matching Adhesive Properties to Operational Priorities

To choose the right formula, it’s essential to define what “performance” means in your process. Most industrial applications revolve around three main priorities:

3.1. Speed: Maximizing Line Throughput

In fast-paced manufacturing environments — especially in packaging and assembly lines — adhesive set time can make or break efficiency.

Hot melt adhesives excel here due to:

• Rapid solidification (within seconds)

• No drying or curing time

• Easy automation with minimal maintenance

To optimize line speed:

• Select formulas with suitable open time — the period before the adhesive sets — to match your conveyor pace.

• Maintain proper application temperature and viscosity to ensure uniform coverage and avoid stringing.

• Use precision applicators to minimize waste and prevent downtime from equipment buildup.

3.2. Strength: Ensuring Long-Term Performance

Strength isn’t just about holding materials together — it’s about resisting mechanical stress, vibration, and environmental factors over time.

For structural or heavy-duty applications, epoxy and polyurethane adhesives deliver superior tensile and shear strength. They maintain performance under load and temperature variations, unlike hot melts, which are thermoplastic and may soften under heat.

Consider:

• Bond type: Structural (load-bearing) vs. non-structural (sealing or positioning)

• Substrate compatibility: Different materials expand at different rates; flexible adhesives prevent joint failure.

• Environmental exposure: Heat, humidity, or chemicals can degrade certain formulas.

3.3. Cost Efficiency: Total Cost of Ownership

When evaluating adhesives, price per kilogram is just one part of the equation. The real cost includes:

• Application efficiency: How much adhesive is needed to achieve the desired bond.

• Equipment maintenance: Clean-running adhesives reduce downtime and part replacement.

• Energy consumption: Lower application temperatures save energy.

• Waste and rework: Consistent bonding prevents defective packaging or assembly rejects.

For example, metallocene-based hot melts often cost more upfront but offer longer pot life, cleaner application, and reduced consumption — lowering total cost per package.

4. Testing and Quality Control

Before full-scale implementation, it’s essential to conduct adhesive testing under real production conditions. Key evaluations include:

• Peel and shear strength tests

• Thermal cycling

• Aging and humidity exposure

• Application compatibility (viscosity and open time validation)

Testing helps identify the ideal formula and application parameters, ensuring repeatability and quality consistency across batches.

5. Common Adhesive Failures and How to Prevent Them

Even the best adhesives can fail if applied incorrectly. Some common causes include:

• Contaminated substrates: Oil, dust, or release agents prevent adhesion.

• Improper temperature or open time: Leads to weak or incomplete bonding.

• Incorrect pressure or coverage: Causes voids or uneven adhesion.

• Over- or under-application: Affects curing and bond line integrity.

Prevent failures by standardizing procedures, maintaining clean surfaces, and training operators on proper adhesive handling.

6. Sustainability Considerations

Modern manufacturers are shifting toward sustainable adhesive technologies, driven by environmental regulations and consumer demand. This includes:

• Low-VOC formulations to improve workplace safety and reduce emissions.

• Hot melts with FDA compliance for indirect food contact in packaging.

• Recyclable or biodegradable adhesives compatible with circular economy goals.

Selecting the right eco-friendly adhesive can support sustainability initiatives without compromising performance.

6. Key Takeaways

Choosing the right industrial adhesive requires balancing speed, strength, and cost efficiency based on your process and materials. Here’s a summary:

In industrial settings, adhesive choice can be the difference between a smooth-running, cost-efficient operation and one plagued by downtime and waste. By understanding adhesive chemistry, process requirements, and performance trade-offs, companies can identify the ideal formula that meets their speed, strength, and cost goals.

A well-chosen adhesive is more than a bonding agent — it’s a strategic component in operational excellence.