On the way to a family celebration or to a job interview; on short drives or on the way to a vacation—cars are our companion in most diverse conditions of life. And because we are driving more and more, they have long since become much more than a means to an end: they express our partialities, our way of life and are a part of our living space. It goes without saying, we want to be comfortable while we are on the move, we do not want to be in a sweat while detained in a traffic jam, we do not want to incur tensions. We want to arrive as refreshed as we started off—after all, the reason for the drive is waiting for us at our destination.
Car seats contribute a great deal to our comfort: They are supposed to ergonomically accommodate driver and passengers, supporting back and body contour. A crucial feature on long haul, it also helps to make short trips more pleasant. sawatex® products for seat applications offer solutions to the most different tasks.
Sandler's diverse nonwovens demonstrate their strengths at first touch: Dimensionally stable variants commend themselves to applications withstanding increased strains and prevent over-expansion of the cover fabric. This way, even after years of use, creasing is not an issue.
Particularly soft and drapeable variants smoothly adapt to the contour of the seat. Yet all of these flexible, lightweight materials have one feature in common: given their open, three-dimensional structure consisting of a multitude of fine fibres they are air-permeable as well as stable. For unrestricted air circulation fostering an optimal micro-climate in the seat. As with all other textiles made by Sandler, these synthetic nonwovens are kind to the skin as well as odourless and are manufactured without chemical binders or additional finishes.
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.
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
STRUCTURE & SURFACE
The fibrous structure of nonwovens combined with diverse bonding technologies creates a multitude of different structures and surfaces, optimising and complementing function and efficiency of these materials depending on their respective application:
No plain surface is like the other. Depending on the requirements of the application, numerous “plain“ surfaces variants are available. A smooth / plain surface also characterises optimised surface integrity.
- Wipes: Smoothing the surface reduces linting. Furthermore, the nonwoven gains a more compact feel and becomes more stable due to a reduction in elongation.
- Automotive industry: Surface smoothing lends stability to the material and improves processability.
- Fashion: A well-bonded surface prevents fibres from penetrating the outer fabric.
Perforating or aperturing offers a specific method of surface structuring. It changes the material’s surface, giving the nonwoven a special design as well as additional functional properties. In wipes substrates perforation improves the cleaning effect: It enlarges the material’s surface area, enhancing its dust hold capacity.
Embossed nonwovens combine design and function. The material can be embossed with various motifs as a visual eyecatcher. In many cases, however, these designs also enlarge the nonwoven’s surface—a definite “plus” when it comes to dirt collection in wipes or absorbency in hygiene products. Multi-layer structures may be bonded via an embossing process, attaining adhesion between the layers without binders. Depending on the material and the utilised polymers these structures can be created thermally or by using hydro embossing. Visit our Design section for more details.
In offices or public spaces embossed acoustic components made of nonwovens may also offer a design feature.
Many Sandler qualities are available with end use oriented print motifs. Various designs for the hygiene and wipes industry emphasise the respective application. Visit our Design section and see for yourself or contact Sandler for your customised print design.
In technical applications such as filtration or construction, performance parameters such as the filter grade, relevant testing standards or the classification pertaining to thermal conductivity can be printed onto the material using inkjet printing upon special request of the customer.
Nonwovens can also be used in the form of composites consisting of several layers. Different nonwovens are combined with one another or with other materials. These multi-layered structures combine the diverse properties and functionalities into one product, fulfilling the highest quality standards. Multi-layer composites may also facilitate processing. The possible combinations are virtually unlimited:
- Hygiene industry: Multi-layer nonwovens combine several functions in one product, such as the transport and storage of fluids.
- Medical applications: Together with other materials nonwovens also function as padding for improved in use comfort, particularly in extended use.
- Wipes: In cosmetics and other applications the combination of fine and coarse layers improves the cleaning effect.
- Automotive & upholstered furniture: Multi-layer nonwovens facilitate processing and lend stability, for example to leather seats: when laminated onto the leather, they prevent overextension in use, thereby reducing unsightly creases in the seat.
- Filtration: Multi-layer composites lend stability to the products: Ceiling filters, for example, are rendered more stable by a polyester fabric laminated to the medium.
- Technical applications: Composites of nonwovens or with a multitude of other materials can increase the stability or even the resistance to heat, acids or other influences.
- Fashion: Lamination to nonwovens imparts optimum surface integrity and prevents pilling and fibre penetration.
CONSERVATION OF RESOURCES
At every stage of the manufacturing process, Sandler relies on sensible raw material usage in order to conserve natural resources. A major focus is thus placed on both preventing and reutilising production waste. Whenever the requirements of the production process will allow, accruing by-products are reprocessed by feeding into production as raw materials. If this internal utilisation is not possible, these surplus raw materials are recycled externally. In this way, both raw materials and nonwovens are part of a closed raw material cycle, conserving valuable resources.
Manufactured without any additives, our single-polymer nonwovens support this recycling philosophy. Sandler polyester nonwovens e.g. in construction applications or in the automotive industry can be recycled after use and reprocessed into new raw materials without having to employ elaborate separation processes. With product specification compliance, recycled polyester fibres are increasingly used—familiar to most every consumer from the recycling of PET bottles.
In selecting raw materials for wipes substrates sustainability is also of major importance. Rayon fibres of European origin derived from controlled forestry and certified according to PEFC™ oder FSC® standards are utilised. The product range also offers biodegradable product variants, made from 100 % rayon fibres.
An energy management system installed directly on our production lines optimises energy consumption and reduces CO2 emissions: energy monitors show the actual consumption during production. Our experienced staff can adjust the settings to minimise energy usage without influencing the properties of the finished product. Use of heat recovery systems further reduces energy consumption. For several years, an energy task force has been monitoring energy consumption throughout the company, identifying potential reductions and proposing measures for implementation.
In their respective applications nonwovens contribute to conserving valuable resources: Durable materials prolong replacement intervals of filters and other products, reducing raw material requirements for replacement products. In the automobile nonwovens also function as heat insulators in the engine compartment, preventing loss of temperature. Thereby, cold starts are reduced; fuel consumption and emissions are lowered and resources are conserved. For this market Sandler developed simulation software in cooperation with partners from the industry. It allows the required product properties to be computer-simulated, foregoing resource-intensive trial productions.
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:
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.
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.
In various applications nonwovens are subjected to permanently high temperatures and/or occasional temperature spikes. The utilisation of specific polymers enables Sandler nonwovens to withstand these conditions. Produced without chemical binders, these materials do not emit vapour under the influence of temperature and remain durable and dependable even in demanding applications.
- Engine compartment: In these applications, nonwovens are resistant to “under the hood” fluids as well as the prevailing temperatures.
- Filtration: In applications such as heat exchange systems filtration nonwovens resist the prevailing temperatures.
- Pipe insulation: In heating and systems engineering as well as in solar systems temperature-stable nonwovens are used.
Sandler tests its nonwovens for temperature-stability in-house. The materials are stored in a compartment dryer for a specified amount of time and any changes to the nonwoven are subsequently reviewed. Climate tests and other analyses documented by test certificates are carried out by external testing institutes.
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.
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.
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 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.
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.
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.