What Is PHR in PVC Film?

When choosing PVC film, softness and flexibility are important factors that directly affect its performance in different applications. One key formulation parameter behind these properties is PHR.

But what does PHR mean, and how does it influence the quality of PVC film?

1. What Does PHR Mean?

PHR stands for Parts Per Hundred Resin. In PVC film manufacturing, it describes the amount of an additive used for every 100 parts of PVC resin by weight.

For flexible PVC film, PHR commonly refers to the plasticizer content in the formulation.

For example, a formulation containing 100 kg of PVC resin and 45 kg of plasticizer has a plasticizer level of 45 PHR.

It is important to note that PHR is a formulation ratio, not a direct hardness measurement. However, it is a useful reference for understanding and controlling the softness of PVC film.

2. How Does PHR Affect PVC Film Softness?

PHR has a direct influence on the flexibility of PVC film. Generally, increasing the plasticizer content makes the film softer and easier to bend, while reducing it results in a firmer material.

In simple terms:

• Lower PHR: PVC film tends to be harder and less flexible.

• Higher PHR: PVC film tends to be softer and more flexible.

However, the final softness is not determined by PHR alone. Plasticizer type, PVC resin properties, and other formulation ingredients can also affect the finished product.

3. Why Choose 42–45 PHR for PVC Film?

For most general-purpose PVC film applications, we recommend a plasticizer level of around 42–45 PHR.

This range offers a practical balance of softness, flexibility, and material stability. It allows PVC film to maintain good flexibility for everyday use without requiring an unnecessarily high plasticizer content.

Of course, different applications may have different requirements. Products that need extra softness may require a higher plasticizer level, while applications requiring a firmer feel may benefit from a lower one.

The ideal formulation should always be determined by the intended application and actual product performance.

4. What Else Affects PVC Film Hardness?

Even when two PVC films have the same PHR value, their final softness may differ. This is because several formulation and production factors work together, including:

• Plasticizer Type: Different plasticizers have different plasticizing efficiencies.

• PVC Resin: Resin characteristics influence the physical properties of the finished film.

• Additional Ingredients: Fillers, stabilizers, and other additives may affect the final material properties.

• Production Process: Processing temperatures and manufacturing conditions also contribute to product consistency.

Therefore, PHR should be used as a formulation reference rather than the only standard for evaluating PVC film hardness.

Conclusion

PHR is an important factor in PVC film formulation because it helps manufacturers control the amount of plasticizer and achieve the desired softness and flexibility.

For many general-purpose applications, 42–45 PHR is a practical choice, offering a good balance of flexibility and material stability.

If you are looking for PVC film with specific softness or flexibility requirements, choosing the right formulation is essential. Contact us to discuss your application and find a suitable PVC film solution.