Selecting the suitable melting temperature for hot melt yarn requires considering the yarn's melting point, the heat resistance of other fibers in the fabric, the processing temperature, and the final product's usage conditions. The following principles and references can guide the selection:
1. Melting Point Should Be About 40°C to 60°C Lower Than Non-Melting Fibers
To ensure that the hot melt yarn melts and bonds during heat setting or bonding without damaging other fibers in the fabric, its melting point is generally controlled to be about 40°C to 60°C lower than that of the non-melting yarns. For example, if the melting point of polyester yarn is around 250°C, the hot melt yarn's melting point should ideally be in the range of 100°C to 165°C.
2. Choose Melting Point Based on Processing and Application Temperature
Low Melting Point Hot Melt Yarn (100°C–130°C): Suitable for heat-sensitive materials, enabling bonding at relatively low temperatures, saving energy, and ideal for packaging, textile composites, and low-temperature processing.
Medium Melting Point Hot Melt Yarn (130°C–160°C): Suitable for general industrial applications, balancing bonding strength and heat resistance, commonly used in apparel, home textiles, and automotive interiors.
High Melting Point Hot Melt Yarn (Above 160°C): Suitable for high-temperature environments and products requiring high durability, such as automotive industry and outdoor equipment, capable of withstanding higher processing and service temperatures.
3. Consider Bonding Performance and Melt Viscosity
If the melting point is too low, the hot melt yarn may prematurely melt during processing or use, resulting in poor bonding. If too high, it may not melt sufficiently to bond well. The melt viscosity also affects bonding quality: higher viscosity favors stronger bonding layers, while lower viscosity suits finer materials.
4. Avoid Using Materials with High Melting Points but Poor Stability
For example, polypropylene hot melt yarn has a relatively high melting point but tends to degrade and emit odors, making it less environmentally friendly and generally not recommended.
5. Match the Melting Point to the Final Product's Usage Environment
If the product will be exposed to high temperatures (such as automotive interiors or industrial equipment), select hot melt yarn with a higher melting point to ensure bonding strength and heat resistance. For products requiring softness and low-temperature processing, lower melting point hot melt yarns are preferable.
Summary Table for Melting Point Selection
| Melting Point Range (°C) | Suitable Applications | Characteristics and Advantages |
|---|---|---|
| 100–130 | Heat-sensitive materials, low-temp processing | Fast bonding, energy-saving, suitable for packaging and textile composites |
| 130–160 | General industrial use, apparel, home textiles | Moderate bonding strength, good heat resistance |
| Above 160 | High-temp environments, automotive, outdoor gear | High heat resistance, high durability |
Ensure the hot melt yarn's melting point is about 40–60°C lower than non-melting fibers and compatible with processing temperatures to avoid affecting fabric elasticity and shrinkage while guaranteeing bonding quality and product performance.
