Plastic Stretch Film Buying Guide
Hangzhou Haimu Technology Co., Ltd. is a plastic stretch film supplier which integrates the design, production, sales and service. We have successfully established rigorous production management system to enhance our management level and have been carrying out standardized production in accordance with national standards to ensure the quality. With years of sustainable development, we have occupied a very important position in the industry and created our own HARDVOGUE brand which bears the principle of "Quality First"and "Customer Foremost" as the basic principle in our mind.
HARDVOGUE focuses our brand strategy on making technological breakthroughs with the growing need of the market to pursue development and innovation. As our technology evolves and innovates based on the way people think about and consume, we have made rapid progress in boosting our market sales and maintaining a more stable and longer relationship with our strategic partners and clients.
Based on our service principle of 'Sincere & Professional & Enthusiastic', we provide our service team with regular training not only about the knowledge of products at HARDVOGUE and the production process but also about communication skills in order to serve all our clients excellently and efficiently.
When using BOPP (Biaxially Oriented Polypropylene) film for in-mold labeling (IML) in injection molding, several challenges may arise during printing, processing, and molding. Below is a detailed breakdown of common problems and corresponding solutions.
1. Printing Issues
Problems:
● Ink adhesion problems: BOPP film has a smooth, non-porous surface, making ink adhesion difficult.
● Ink drying issues: Some inks dry too slowly on BOPP, leading to smudging or incomplete curing.
● Color variation or poor opacity: The ink may not appear as expected due to the film’s transparency or reflectivity.
Solutions:
✅ Use IML-compatible inks, such as UV-curable or solvent-based inks, to improve adhesion.
✅ Perform surface treatment (e.g., corona treatment or primer coating) to increase surface tension and ink bonding.
✅ Choose white or opaque BOPP films for better color consistency and opacity.
2. Static Electricity Problems
Problems:
● Film sticking together: High static charge causes BOPP labels to stick, making feeding and handling difficult.
● Dust attraction: Static buildup attracts dust and debris, which can affect print quality and mold adhesion.
Solutions:
✅ Use anti-static treatments or coatings on the BOPP film to reduce static buildup.
✅ Install ionizing bars in the production line to neutralize static charges.
✅ Maintain proper humidity levels in the production environment to minimize static electricity.
3. Die-Cutting and Label Handling Issues
Problems:
● Poor die-cutting precision: BOPP’s toughness can cause rough or uneven cuts.
● Edge curling: Improper cutting or tension control may lead to curled labels, affecting placement in the mold.
● Film tearing or warping: Incorrect tension during processing can damage the labels.
Solutions:
✅ Use sharp, high-precision dies and optimize cutting pressure for clean edges.
✅ Control web tension in the cutting process to prevent label warping.
✅ Use multi-layer BOPP films that provide better stiffness and stability.
4. Adhesion and Bonding Problems in the Injection Mold
Problems:
● Label shifting inside the mold: If the label does not stay in place, it can cause misalignment or defects.
● Weak bonding with plastic: BOPP film may not adhere well to the injected plastic, leading to peeling.
● Wrinkling or air bubbles: Poor label positioning or excessive mold temperature can cause defects.
Solutions:
✅ Use static charge or vacuum systems to hold the label in place before injection.
✅ Ensure the film is coated with a suitable anchoring layer for better adhesion to the molded plastic.
✅ Adjust mold temperature and injection pressure to minimize air entrapment and improve label integration.
5. Temperature and Shrinkage Issues
Problems:
● Film shrinkage or distortion: High temperatures during molding can cause the BOPP label to shrink unevenly.
● Dimensional stability problems: If the film expands or contracts too much, it can lead to misalignment.
Solutions:
✅ Use high-heat-resistant BOPP films specifically designed for IML applications.
✅ Ensure proper label conditioning before molding to minimize expansion or shrinkage.
✅ Control mold temperature and injection cycle time to reduce thermal stress on the label.
6. Environmental and Storage Problems
Problems:
● Film brittleness in low temperatures: BOPP can become brittle in cold storage conditions.
● Moisture-related issues: High humidity can affect ink adhesion and cause film distortion.
Solutions:
✅ Store BOPP film in a controlled environment with stable temperature and humidity.
✅ Use protective packaging to prevent dust and moisture exposure.
✅ Allow films to acclimate to room temperature before printing and molding.
Summary Table
|
Issue Category |
Specific Problems |
Solutions |
|
Printing Issues |
Ink adhesion problems, slow drying, poor opacity |
Use IML-compatible inks, surface treatments, and opaque films |
|
Static Electricity Issues |
Labels sticking together, dust attraction |
Apply anti-static treatments, use ionizing bars, control humidity |
|
Die-Cutting Issues |
Rough cuts, edge curling, film warping |
Use sharp dies, control web tension, choose multi-layer films |
|
Molding Adhesion Issues |
Label shifting, weak bonding, wrinkles/bubbles |
Use static charge or vacuum systems, adjust mold conditions |
|
Temperature Issues |
Shrinkage, dimensional instability |
Use high-heat-resistant BOPP, control mold temperature |
|
Storage Issues |
Brittleness in cold, moisture effects |
Store in a controlled environment, acclimate before use |
Offering IML-grade BOPP films that are pre-treated for printing, anti-static properties, and high-temperature resistance will improve product performance and processing efficiency.