Vegan Lip Balm/Deodorant Leaking from the Bottom During Hot Filling?
Analyzing 3 Core Packaging Techniques for Leak-Proof “Hot Filling”
Q: Our brand specializes in vegan skincare, and we’ve long wanted to switch to paper packaging to support environmental sustainability. However, we ran into a major problem during trial production: Our lip balms and deodorant sprays are produced using the “hot pour” process. As soon as the molten product is poured in, it leaks out through the gaps at the bottom of the paper tubes before it has a chance to cool and set. This not only wastes expensive raw materials but also leaves the tubes covered in oil stains. What exactly is causing this? Is there a solution?
A: This is a very common pain point in custom beauty packaging. The issue you’re facing is actually a physical limitation that many brands tend to overlook when transitioning from plastic packaging to “all-paper packaging.”
Why can’t ordinary paper packaging “contain” hot-filled products?
In our packaging production facilities, we often see clients taking their existing formulas designed for plastic tubes and forcing them into paper tubes—with disastrous results. Generally speaking, paper is highly absorbent, primarily for two reasons:
1.
Material property conflict: Paper tubes are essentially made of fibers. Standard industrial adhesives soften rapidly at high temperatures, and the gaps between fibers create capillary action under thermal stress, allowing oils to penetrate instantly.
2.
Structural tolerance issues: Many factories simply insert a round paper disc when sealing the bottom of paper tubes, without considering the flow characteristics of hot liquids or the pressure from potential leaks.
To achieve 100% leak-free hot filling, you need these two “lines of defense”:
To completely solve the problem of bottom leakage during hot filling, simple blocking is not enough; a comprehensive upgrade in both structure and materials is essential:
First Line of Defense: “Heat-Resistant Coating” on the Inner Wall We cannot allow the molten paste to come into direct contact with the paper fibers. We must laminate a food-grade heat-resistant plant-based PLA or high-temperature-resistant PE coating onto the inner wall of the paper tube. This coating acts as a dense “barrier” that can withstand high-temperature filling at 80°C–100°C while providing perfect release properties after the paste cools, ensuring the paste dispenses smoothly without sticking to the tube walls when consumers use it.
Second Line of Defense: High-Density Extrusion Sealing Process This is the most critical physical defense. Ordinary paper insert solutions are doomed to fail. We employ a high-density die-cutting and mechanical extrusion sealing process, using precision equipment to control the tolerance between the base and the inner diameter of the tube wall to within 0.1 millimeters. For push-type lipstick or deodorant tubes, preventing leakage at the bottom typically requires a paper base thickness of 5–6 mm. Additionally, by controlling the paste temperature—generally maintained between 60–80 degrees Celsius—the paste achieves zero leakage.
Translated with DeepL.com (free version)