Wisdom For Polyethylene vol.6

6. The Ways for Sealing

2024-05-30

There are two ways to seal polyethylene tubes with a machine:

(1) Cut-and-Seal Method

In this method, the polyethylene tube is cut before sealing, so no tension is applied to the seal during feeding. As a result, the seal does not stretch, allowing for a thicker, stronger seal. Our comparisons show that this method can achieve a seal strength more than 25% higher than the alternative, and this is the method we use in production.

(2) Seal-and-Cut Method

In this method, the polyethylene tube is sealed before being cut (the tube remains connected during sealing). Consequently, tension is applied to the sealed part when the tube is fed to the next process, causing the seal to stretch. Stretching leads to thinning, which makes it difficult to achieve high seal strength at the point of sealing.

Summary: How to Choose a Sealing Method

Item	Cut-and-Seal Method	Seal-and-Cut Method
Seal Strength	High	May be Slightly Inferior
Production Speed	Slightly Slow	High Speed
Main Applications	For products requiring high durability	Mass production, speed priority

The cut-and-seal method is suitable for increasing seal strength, and it is especially optimal for applications requiring high durability.

On the other hand, the seal-and-cut method contributes to improved production efficiency, but the strength of the sealed part tends to decrease.

It is important to select the appropriate sealing method according to the intended use and required quality standards.

7. Additives In Polyethylene Raw Material