Breathability describes a fabric‘s ability to allow air and water-vapour to permeate, preventing the accumulation of moisture. Breathable materials thus increase comfort in use and avert skin irritation, particularly in applications involving direct skin contact. 

• Hygiene products & wound dressings: Breathable nonwovens allow the skin to breathe, increasing wear comfort whilst preventing an accumulation of fluids and skin irritation, particularly during extended use.
• Automotive: Breathable textiles in the car seat increase driving comfort, especially on long journeys. 
• Construction industry: Permeable nonwovens contribute to the health of the occupants. They allow the walls of buildings to breathe when required. Simultaneously, they avert the accumulation of moisture, thus preventing structural damage and potential health issues caused by mould formation.
• Mattresses & bedding: Breathable materials allow for a restful and comfortable sleep.
• Fashion: Breathability is a vital function for product performance. 

Breathability, also referred to as resistance to water vapour permeability, can be measured according to DIN EN 31092, respectively ISO 11092 using the thermo-regulatory model of human skin. Breathability indicates the rate at which perspiration is transported through the material. 

Extensible nonwovens facilitate contouring of the material to the respective application: 

• Hygiene products: In diaper ears and other stretch applications, elastic nonwovens enhance this characterisation. They flexibly adapt to the wearer’s body, adjusting to any movement and optimising comfort in use. Extensible under a low load, with excellent recovery properties.
• Automotive, technical applications & home textiles: Malleability is a key requisite when nonwovens have to follow a contour. These nonwovens facilitate processing and dependably insulate or protect complex components. 
• Construction: Used in repairs to a façade for example, elastic nonwovens are applied in crack bridging. They adapt to expansion or shrinkage of building materials and are capable of recovering their original dimensions, offering a long-term solution to construction defects.

Extensibility is measured by determining the maximum tensile force and the maximum elongation according to WSP 110.4 in machine direction and cross machine direction. Sandler performs these tests in our in-house laboratory.
Elastic properties are determined by employing the so-called hysteresis test following DIN 53835. During these tests, the material is repeatedly stretched up to a defined maximum tensile force. The maximum elongation achieved at the predefined force as well as the material’s permanent set are measured. The ideal permanent set value is required to be as low as possible, signifying that the material does not wear out during use. These tests are also performed in Sandler’s in-house laboratory.

Health is our greatest asset; protecting it is Sandler’s philosophy. Using specific combinations of raw materials and manufacturing technologies, Sandler nonwovens actively contribute to furthering this objective. They may be made of polyester from recycled drinking bottles and even the single-polymer nonwovens used in our clothing styles are fully recyclable. Sandler does not employ any chemical additives in the manufacture of these materials and furthermore, they are odourless. These nonwovens therefore protect the health of converters and end-users alike. 

In processing and using synthetic materials, various emissions may occur. Some examples of these are:

• total carbon emissions; measured according to the VDA 277 standard 
• odours; for which the material is tested according to VDA 270-C3 
• formaldehyde emissions; measured according to VDA 275. This substance may cause headaches, mucosal irritation or respiratory problems and can even trigger asthma or allergies upon long-term exposure.
• fogging—condensation on windows in vehicles generated by the aforementioned emissions; measured according to DIN 75201

Materials for a defined product are specially chosen to avoid these emissions, resulting in Sandler nonwovens falling below the accepted limits in all of these categories. 

• Hygiene & wipes industry: These products are intended to protect the well-being of the user, while remaining virtually unobserved. Only high-quality base materials are selected to which rigorous criteria are applied in order to ensure a low level of emissions. Sandler applies no chemical additives to avoid the generation of unpleasant odours.
• Automotive industry: Sandler nonwovens do not release unpleasant or harmful emissions—designed for comfortable handling and long-term enjoyment. 
• Filter media: In ventilation and air-conditioning systems Sandler nonwovens allow us to breathe freely without having odours and other emissions impairing the air quality.
• Insulation materials for construction: In buildings, low-emission Sandler nonwovens are an excellent alternative for people suffering from allergies, contributing to the preservation of the occupants' health. 
• Acoustics in offices & home textiles: Sandler nonwovens are odourless and virtually free from formaldehyde*, rendering both workplace and our homes as real comfort zones.

In cooperation with our partners, Sandler also offers an anti-odour finish that eliminates odours, for example for nonwovens applied in vacuum cleaner bags.  

* below the detection limit

Nonwovens facilitate optimum air circulation owing to their porous structure which also makes them permeable to other substances. According to DIN EN ISO 9237, air-permeability is determined by clamping a flat sample of material into a testing device and passing an air stream through it at a defined differential pressure. The flow resistance is measured.

• Automotive: Sandler nonwovens are acclaimed as open-pore upholstery materials for seating, particularly for actively ventilated climate seats.
• Technical applications: Applied as processing aids, frequently in combination with other materials, nonwovens protect delicate surfaces. Their air-permeability can be tailored to the specific application and they remain air-permeable, even when retaining other substances.

Pressure drop
In filtration, the relevant factor is the interaction of air-permeability and the pressure drop, induced by the filter’s flow resistance. The pressure building up in front of the filter is higher than that behind the filter. A low pressure drop in combination with a high air-permeability of the filter medium reduces the amount of energy necessary to force the required amount of air through the filter—a contribution to the filter’s energy efficiency and to long-term cost-savings in the operation of the filtration plant. The durability of Sandler nonwovens further supports these savings by prolonging the filter’s operating life and reducing replacements.
 
The pressure drop is tested according to WSP 70.1 by measuring the filter’s flow resistance in a defined volume flow. Multiple measurements at varying volume flows can be aggregated into a curve depicting the development of the pressure drop. Sandler nonwovens are tested for this property online during production as well as by external institutes and customers. These external partners conduct tests using flat material samples as well as ready-made filters from Sandler material.
Further relevant standards on this subject are DIN 53887 and DIN EN ISO 9237.

See also: Breathability

In furniture, in hygiene products, in the automobile, in outdoor jackets and as industrial cushion liners for packaging, these nonwovens facilitate processing, contribute to the end-product’s durability and protect surfaces. The following properties are relevant to this characteristic:

Recovery rate

The recovery rate describes a material’s ability to relax or regain its original shape after long-term, constant strain.

• Hygiene industry: In this sector, elasticity and stretch are important for nonwovens used in diaper ears and other closures.
• Automotive: A high recovery rate in nonwovens used in seats provides for long-term driving comfort. These nonwovens yield to deformation, yet remain stable.
• Upholstered furniture: Nonwovens featuring a high recovery rate render furniture durable and contribute to a high level of long-term comfort.
• Mattresses: The formation of dents and creases can be prevented, resulting in permanently comfortable sleep.

In technical applications, the parameters for testing this property are stated in DIN 53517 or DIN ISO 815. The so-called compression set value as measured is expressed as a percent. A sample is compressed by a defined value and held in this state for a given time at a defined temperature, the specific test parameters being dependent on the intended application. 30 minutes after relaxation the material’s thickness and plastic deformation are determined. For hygiene products, the material’s elastic properties are measured by means of the hysteresis test following the procedure in DIN 53835.

Volume

Voluminous nonwovens are particularly bulky for improved visual effect, processability and performance:

• In furniture these nonwovens create unrestricting bulky upholstery, particularly for soft upholstery in the backrest—perfectly suited to the latest design trends.
• Mattress covers are even more comfortable with voluminous nonwovens.
• In outdoor clothing voluminous materials provide for a higher level of heat retention.

Flame-resistant products meet particular demands in the event of fire. Subjected to blaze, sparks or open fire, they do not catch fire immediately. When ignited, these structures do not continue to burn, but extinguish after a specific time.

Depending on the specific application and national regulations, various test standards apply:

• Automotive applications: DIN 75200, MV SS 302, PV 3357 and UL 94
• Filtration: The provisions regarding flame-resistance are laid down in DIN 53438 standard.
• Construction: Nonwovens for office fittings and mattresses used on ships and trains are evaluated according to DIN 4102 or DIN EN 13501 standards.
• Upholstered furniture: BS 5852 standard is decisive in this sector.

Our nonwovens are tested for flame-resistance in cooperation with external testing institutes.

Finishes

Sandler nonwovens can be offered with different finishes to supplement functionality: for example with lotions, cleaning agents, an antibacterial finish or a flame-retardant finish to increase flame-resistance.

Printing

Nonwovens can be printed all-over or with detailed motifs using thermal transfer printing, digital printing, flexo printing or other established printing technologies. 

• Hygiene & wipes industry: Print motifs emphasise the application and offer visual differentiation. 
• Office design: Acoustic components for interior decoration can be printed to offer a design facet. Thermal transfer printing increases surface bonding and smoothes the nonwoven’s surface.

With the intention of improving the print result, the surface of Sandler nonwovens may also be pre-treated by roughening the fibres.

Adhesive coating

Adhesive coating can be applied on one or both sides of the nonwoven. In filtration for example, ceiling filter media are coated with an adhesive finish to facilitate processing in the end application. The coated parts are protected by a release film. Once this film is removed, the nonwoven can be used as intended. Pleatable filter media can be equipped with spacers made of hotmelt adhesive.

The nonwoven can also be pre-treated to enlarge the fibres’ surface to improve bonding with the adhesive.

Pleating 

Sandler's pleatable nonwovens for the filtration industry are suitable for processing on knife as well as rotation pleating lines. A homogenous, longitudinally oriented fibre structure provides for particularly accurate pleating and high pleat depths. The polymers utilised are temperature-stable, elastic and resistant to breakage, thus offering high stability: The pleats are dimensionally stable, yet are also flexible. They withstand mechanical influences during processing and temperature and humidity during use.

Cutting & die-cutting

Sandler nonwovens are easy-to-process using established cutting technologies such as band knives, CNC cutters, straight knives, water-jet cutting or laser cutting. Perforation cuts for tearoff wipes, for example, are also possible.

For hygiene products, automotive industry products, and for mat filters die-cutting is used, to which Sandler nonwovens are highly suited. Particularly in automobiles precision contouring facilitates accurate assembly onto the particular component. The material is also not distorted during die-cutting, resulting in accurate cuts with clean edges.

Sewing

By selecting appropriate fibres, Sandler nonwovens are easily processable and can be sewn without difficulty—in the manufacture of fashion, mattress covers, car seats, and for pipe insulation or the production of pocket filters.

Embossing

To achieve adhesion between layers, as an eye catcher or for the selective deformation of voluminous materials: Sandler nonwovens are embossed for a variety of applications. They are well suited to both calender and ultrasonic embossing, frequently used for the hygiene industry. In the automotive sector, embossed nonwovens are also used for example in engine cover parts. Again Sandler nonwovens are ideally suited to the processes employed in this industry, such as hot and ultrasonic embossing.

Moulding

Due to the thermoplastic properties of the selected polymers utilised Sandler nonwovens are mouldable and are able to match the contours of the component. In addition, the material can also be hardened through moulding.

• Automotive industry: Nonwovens are for example processed into 3D moulded parts such as headliners or wheel house liners.
• Interior design: Acoustically efficient moulded parts made of nonwovens are also making advances into interior design. One recent example: a designer lamp shade. 

In the filtration industry nonwovens are generally pre-heated prior to pleating. Sandler nonwovens are well suited to this process.

Welding

The polymers used make Sandler nonwovens totally compatible with ultrasonic welding, high-frequency welding or thermal welding techniques.  

• Automotive industry: Ultrasonic or high-frequency welding spots are used to fasten nonwovens to die-cut or cover parts.
• Filtration & hygiene industry: Multi-layer composites can be bonded using ultrasonic or high-frequency welding.
• Technical applications: Nonwovens for pipe insulation are sealed using common welding technologies.

Laminating

Depending on the specific application, Sandler nonwovens can be laminated with different materials to produce multi-layer structures with multifunctional properties: for improved acoustic efficiency, hardening, greater stability, resistance to heat or for improving mechanical properties. In fashion, the nonwoven is bonded to the outer fabric, in hygiene products multi-layer structures combine reliable protection with comfort in use—the possibilities are virtually endless.

In the hygiene industry, nonwovens are frequently transported to the laminating line on a vacuum conveyor belt. This process poses specific demands on the material’s air-permeability and Sandler nonwovens provide these characteristics.

Sandler nonwovens for the fashion industry and for matress covers are suitable for washing and dry cleaning. Depending on the outer fabric, they exhibit relatively low shrinkage.