Antistatic Filters

Reinforcing filters with antistatic
BAFA® laid scrims

We supply filter manufacturers with antistatic laid scrims.

BAFA^® laid scrims containing stainless steel fibres not only add antistatic properties to filters but also provide structural reinforcement and higher tear strength.

Antistatic properties

Electrostatic charges – caused, for example, by nonwovens rubbing against surfaces or by particles in an air flow – must be discharged via earthing in certain applications, such as potentially explosive atmospheres.

As an integrated metal-containing laid scrim, a BAFA^® laid scrim can be connected to a protective or functional earth via an earthing tab or earthing stud.

This makes it suitable for ventilation systems, particularly in potentially explosive atmospheres: for gas explosion protection under the ATEX Directive (II G / IIA–IIC (X)), in Zones 1 and 2 according to EN 1127-1, and for solvents of explosion groups IIA to IIC (X).

Unlike antistatic additives, laid scrims last at least as long as the nonwoven they are bonded to.

Tear strength at minimal weight for filters

For filters, the combination of tensile loads and safety requirements calls above all for tear strength – at minimal weight. Especially at areal weights below 100 g/m² (approx. 2.9 oz/yd²), any reinforcement must also be lightweight.

Engineers looking for this kind of reinforcement should consider laid scrims.

They are suitable for reinforcing all categories of filter media, for example:

• Air filters
• Liquid filters
• Bag filters
• Pleated filters
• Gravity belt filters
• Pressure belt filters
• Vacuum belt filters
• Filter drainage sleeves
• Filter laminates
• Filter mats

What are laid scrims?

Laid scrims are lightweight yarn structures. Like nonwovens, they are not woven.
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‍Laid scrims differ significantly from conventional woven fabrics:

• The yarns are not interlaced over and under each other but firmly bonded at their contact points by a binder.
• The yarns run diagonally / multiaxially in 6 to 10 directions, so they absorb acting forces much more effectively.
• Yarn spacing and orientation can be freely adapted to the application and the properties required. With wide yarn spacing, they do not impair the flow and filtration properties of filter media.
• They are more stable and at the same time more flexible.
• Their higher structural tear strength allows wider meshes and a significantly lower weight per unit area.
• Different materials can be combined, each with its specific properties.
• The yarns can be treated with a wide range of impregnations and binders for specific purposes.
• Moisture-resistant
• Temperature-resistant up to the upper limit of filters and nonwovens
• Shape-stabilising
• Durable
• Cost-effective

Added value through design and function

Laid scrims are usually hidden as an intermediate layer in sandwich constructions. That does not exploit their full potential: beyond their function, laid scrims offer another valuable option:

they can make the added value of high-tech products visible.

Under transparent surfaces or as the top layer, laid scrims offer interesting design options. Depending on yarn thickness, density and angle, products can look more delicate, more robust, or both.

Processing in automated production

BAFATEX supplies laid scrims wound on rolls, designed for automated production and high processing speeds. With BAFA^® laid scrims, manufacturers save time in converting. The laid scrims are usually processed as an intermediate layer in sandwich constructions, where they also prevent the layers from shifting.

BAFA^® laid scrims are easy to cut and punch, making them suitable for both manual processing and die-cutting lines.

With BAFA^® laid scrims, filter media can be processed as roll goods, cut sheets, filter bags or die-cut parts.

Material options

Depending on the properties required, the following materials are available:

• Natural fibres: jute, cotton and flax (more information)
• Man-made fibres (more information)
• Other materials on request

Glass fibre and carbon are the two most widely used materials for reinforcing rackets and bats, both offering a long service life under strongly fluctuating loads. Typical construction for a ski, for example: carbon weft yarns in BAFA® laid scrim 100/20 made from 1100 dtex black polyester combined with 1210 dtex Twaron®.

Individually configurable

Several variables can be adjusted to tailor the reinforcement to your requirements:

• Material, material combinations and their properties (e.g. soft, hard, heat-sealable, waterproof, flame-retardant)
• Impregnation / adhesive
• Yarn count and yarn spacing
• Elongation at break (1.7–23 %)
• Breaking force (2.2–448 N)
• Tenacity (13–355 cN/tex)
• Crossing angle of the yarns (and thus force transmission)