Differences between Injection Grade TPU and Extrusion Grade TPU

Full professional English explanation

1. Injection Grade TPU  Melt flow index (MFI)：High fluidity, low melt viscosity. -

**Processing characteristics**：Suitable for rapid mold filling, thin-wall parts, complex structures, multiple gates and precision injection molding.  **Molecular structure & hardness distribution**：Narrow molecular weight distribution, good thermal stability during short-time high-temperature injection.

**Main applications**：Shoe soles, buckles, seals, hardware wrapping, precision elastic parts, small molded components.

**Features**：Easy demolding, low internal stress, excellent surface finish of finished products.

2. Extrusion Grade TPU **Melt flow index (MFI)**：Low fluidity, high melt viscosity, strong melt strength.

**Processing characteristics**：Resists melt breakage, stable continuous extrusion, good necking resistance under constant high temperature. – **Molecular structure & hardness distribution**：Wide molecular weight distribution, superior long-term heat resistance and melt elasticity. -

**Main applications**：TPU films, tubes, hoses, cables, wire sheathing, belts, profiles, sheet materials.

**Features**：Uniform continuous molding, good drawability, stable dimensional stability after extrusion.

## Concise Contrast Table (for product label / material specification) | Item | Injection Grade TPU | Extrusion Grade TPU Melt Viscosity | Low | High | | Fluidity | Excellent | Poor | | Melt Strength | General | Very high | | Processing Method | Injection molding | Extrusion molding | | Processing Time | Short high-temperature residence | Long continuous high temperature | | Typical Products | Molded parts, soles, fasteners | Films, hoses, cables, sheets |

**Injection grade TPU** is designed for injection molding with good flowability to fill molds quickly.

**Extrusion grade TPU** has high melt strength for continuous extrusion into films, pipes and cables.