Synthetic silica: the best anti-block solution

Synthetic silica: the best anti-block solution

Wednesday, 2 July, 2025

Comindex introduces HOMBLOC^® by Lingwe for film applications

An anti-block additive is a substance in the form of fine particles added to plastic materials —especially thin films such as those used in packaging— to prevent them from sticking to each other during manufacturing, stacking or winding.

Why is it needed?

When they are manufactured, plastic films tend to adhere to one another due to:

Electrostatic forces
Pressure during winding
Extremely smooth surfaces, which create a vacuum between layers

This sticking can complicate handling during packaging or printing processes.

How is it incorporated into film?

The anti-block additive—typically a fine powder composed of small particles—is introduced during the film extrusion process via an additive concentrate, also known as a masterbatch. In this masterbatch, the anti-block particles are pre-dispersed in a polymer matrix, allowing for uniform distribution of the additive throughout the film.

How does it work?

The anti-block additive creates invisible particles on the film surface. These:

Generate a microtexture that reduces direct contact between layers.
Make it easier to separate film layers.
Improve efficiency on high-speed production lines.

Illustration 1. Film production process – from the LINGWE catalogue

Comindex is pleased to be able to offer the HOMBLOC^® range of synthetic silica-based anti-block additives from manufacturer Lingwe. Thanks to its unique technology, HOMBLOC^® significantly reduces the coefficient of friction on the film surface, making downstream production processing smoother and improving both production efficiency and film quality. This synthetic silica-based product exhibits several advantages when used as an anti-block agent:

High anti-block efficiency
- Its porous structure and large surface area reduce layer-to-layer contact, preventing adhesion.
- Available in grades with narrow particle size distributions.
Excellent polymer compatibility
- It performs well in a wide variety of plastics such as PE, PP, PET, among others, without compromising mechanical or optical properties.
Maintained transparency
- Unlike other anti-block agents, synthetic silica can preserve film clarity, which is critical for packaging applications.
Non-toxic and safe
- It is made from high-purity, chemically inert, non-toxic and non-contaminating materials, ideal for food-contact applications.
Thermal and chemical stability
- It withstands high processing temperatures and remains unreactive with other plastic components, making it suitable for extrusion and blow-moulding processes.
Enhanced production performance
- Facilitates film unwinding and handling on high-speed production lines, reducing downtime and jamming.
Durability and slip resistance
- Improves resistance to creep (gradual deformation under load) and friction, extending the lifetime of the finished product.

Illustration 2. Different HOMBLOC^® synthetic silica grades according to particle size and porosity (source: Lingwe Catalogue).

Within the broad HOMBLOC^® silica range, Comindex can help you identify the most suitable anti-block additive for your specific application needs.

Do not forget that here at Comindex we can support you throughout your process. Simply contact our team of technical sales advisors.

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