Frequently Asked Questions


How does Pireta’s technology work?

Pireta’s technology uses an innovative chemical process to add electrical conductivity to areas of fabric. The conductivity is provided by a very thin metallic coating that is chemically bonded to the fibres in the textile. The process, which incorporates a printed step, is free form and selective – almost any conductive pattern can be printed directly onto an existing textile. Our technology allows electronic systems to be assembled directly on fabrics, enabling a new generation of truly wearable smart garments and e-textiles.

The process has no impact the handle, drape, stretchability and breathability of the textile, adds negligible weight and allows conductivity to be added discretely, only where needed. Rather than adding a separate conductive layer or thread to the fabric, Pireta’s process makes the textile itself conductive.

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Glove made using e-textiles can control robot hand

What steps are involved in Pireta’s process?

Pireta’s process is based on straightforward aqueous chemistry, utilising commercially available equipment, and involves five key steps:


Step 1:

The fabric is pre-treated.

Step 2:

The fabric is activated by applying a chemical linker.

Step 3:

A nanometal catalyst is selectively applied to the fabric.

Step 4:

The metal layer is thickened using an electroless plating process. .

Step 5:

Finally, a metallic or organic passivation layer is applied.

What can the conductive patterns be used for?

Pireta conductive patterns can be used as an interconnect technology that enables electronic systems to be assembled and interconnected directly on fabrics. As well as providing an ideal component interconnect solution for e-textiles, Pireta’s technology can be used to implement sensors and transducers.

Pireta conductive tracks can transmit RF signals of up to 5GHz in frequency, and antennas can be created using conductive patterns printed directly on a textile. This attribute of the technology enables straightforward integration of wireless technologies, such as NFC, RFID, Bluetooth and Wi-Fi into e-textiles and smart garments.

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Does Pireta’s technology add weight to the textile?

The conductivity is provided by a very thin metallic coating that is chemically bonded to the fibres in the fabric. Because this coating is only a few microns thick – and because conductivity can be applied selectively, only where needed – the process adds negligible weight to the textile.

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What level of conductivity is achieved?

Because Pireta’s process coats the fibres in the fabric with metal and therefore makes the textile itself conductive, the level of conductivity achieved will depend on the fabric itself. The level of conductivity achieved will be dependent on the number of threads per unit area, and the number of fibres in a thread, and hence the final conductivity is dependent on the total surface area of fibres in the fabric. Fabrics with a greater density of fibres per unit area will, generally, result in higher levels of conductivity. In order to simplify calculations, Pireta uses sheet resistance to indicate the level of conductivity (or, in fact, resistivity) achieved with its process.

Typical sheet resistance levels lying in the range 10-100 mΩ/square. This level of conductivity is not only suitable for signal tracks, but it can also be perfectly acceptable for distributing power. For example, a track that is 100mm long and 10mm wide could have a total resistance of 100mΩ (i.e. 10 squares at 10m Ω/square).

For applications that require higher levels of conductivity, it is possible to incorporate an additional plating step that increases the thickness of the base metal coating in order to reduce the sheet resistance further.

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What metal is used to provide the conductivity?

Although Pireta’s process is compatible with several base metals, Pireta is currently using copper as the metal that is plated onto the fibres to add conductivity to the printed patterns. Copper has been selected due to its excellent conductivity, wide availability and relatively low cost. In addition, copper also allows direct soldering to tracks and pads on the fabric.

Because copper will oxidise when exposed to air and lose conductivity as a result, a passivation layer is applied to prevent this oxidation. This passivation layer can be a noble metal, such as silver or gold, or an organic compound. The metal coating, which is applied with an immersion plating step, is extremely thin so does not add significant cost.

If an organic compound is used, this can also provide electrical isolation. This prevents the tracks from shorting out when in contact with each other or another conducting medium (for example, human skin with perspiration).

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Knitted fabric turned into e-textile through conductive pattern

What is the maximum current that can be carried?

The maximum current capacity will be determined by Ohm’s law and the acceptable level of voltage drop, power dissipation and loss for the application in question. For example, a track that is 100mm long and 10mm wide with a sheet resistance of 10mΩ/square would have a total resistance of 100mΩ. If a current of 5Amps flows though this track, then this would dissipate 2.5watts of power and result in a voltage drop of 0.5 volts.

Note that it is often the case that space is not at a premium for interconnections on smart garments and e-textiles. By using this space, tracks can be widened in arbitrary, free-form patterns in order to reduce their resistance. Conversely, in heated garment applications, tracks can be reduced in width in areas where higher resistance and heating is required.

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What is the maximum stretch/strain you can achieve while also maintaining conductivity?

In principle, there is no limit (subject to the stretch capacity of the textile). However, the conductivity will vary somewhat as the fabric is stretched.

In general, stretchable fabrics are knitted. Under force, it is the stitches in the knitted patterns that deform, rather than any significant elongation of the yarns or fibres that make up the textile. The elastic behaviour of the fibres is what causes the fabric to recover its original shape/dimensions after being stretched.

Pireta’s technology makes the fabric itself conductive. This is achieved by coating the fibres in the textile with a very thin layer of metal. When the fabric is stretched, the fibres are free to move relative to each other, and to deform. This movement simply causes the conductive paths between fibres to be re-arranged, but not interrupted. As the fabric reaches maximum strain, the conductivity typically increases due to the fibres being pulled together tightly.

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Why does Pireta’s technology have no impact the handle, drape, stretchability and breathability of the textile?

Typically, fabrics are knitted or woven from yarns or threads that have been created by spinning together a bundle of fibres. Pireta’s process is applied at the fibre level, coating the individual fibres with a layer of copper that is only a few microns thick. As a result, the fibres retain their ability to deform and move, avoiding any impact on the handle, drape or stretchability of the fabric. Furthermore, any gaps between yarns and stitches are unaffected, meaning the fabric will retain any natural breathability. This is a major advantage over printable conductive inks, that are typically applied onto of a non-permeable plastic/TPU interposes layer that is bonded to the fabric. In addition to preventing the fabric breathing, these layers have very limited stretchability.

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Are Pireta conductive tracks suitable for RF applications?

Yes. Pireta conductive tracks can transmit RF signals of up to 5GHz in frequency, and antennas can be created using conductive patterns printed directly on a textile. This attribute of the technology enables straightforward integration of wireless technologies, such as NFC, RFID, Bluetooth and Wi-Fi into e-textiles and smart garments.

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Are Pireta conductive tracks washable?

Yes. We have carried out wash tests on samples involving 100+ wash cycles at 30C. Conductivity is maintained and there is no detectable amount of the metals (that provide the conductivity) in the wash effluent.

Note that wash test verification would need to be carried out on customer-specified fabrics.

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How can connections be made to Pireta conductive tracks?

Because Pireta conductive patterns are metallic, and provided the host textile has sufficient temperature resistance, electronic components and connectors can be soldered directly to tracks and fine-geometry pads created with the Pireta process. There is no limit on solder temperature imposed by the Pireta conductive tracks. Depending on the fabric, low temperature solders may be required.

Pireta’s technology is also compatible with other connection technologies and systems, including crimping/compression type connectors for e-textiles, conductive adhesives and conductive threads. Please contact Pireta directly for further information on the use and compatibility of specific connection technologies.

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How can the conductive patterns be electrically isolated/insulated?

The conductive patterns can be isolated by application of an organic liquid that cures in-situ. This type of compound can also act as a passivation layer to prevent oxidation of the underlying conductive copper layer.

Other approaches are also possible. For example, an additional layer of fabric could be used. Laminated layers or printed / stencilled TPU layers are also possible, although these approaches may impact on the performance of the fabric.

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Can the conductive patterns be electrically isolated selectively (leaving certain areas conductive)?

Yes. The conductive patterns would be isolated by selectively printing the organic liquid over the areas of the conductive pattern to be isolated. As with standard electronics assembly, conformal organic coatings can be readily patterned.

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What is the minimum track width / feature size than can be produced?

As with other parameters, this will depend on the textile. Pireta’s technology makes the fabric itself conductive. For this reason, track widths of less than the inter-stitch or weave pattern are not likely to provide reliable levels of conductivity. For typical fabrics, “track and gap” dimensions of 1mm are achievable. Smaller dimensions may be possible on finer fabrics.

Note that, it is often the case that space is not at a premium for interconnections on smart garments and e-textiles. Although it may be necessary to use fine features around components and connectors, away from these tracks can be widened in arbitrary, free-form patterns in order to reduce their resistance.

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What types of textile can the process be used on?

The process can be applied to a wide range of knitted, woven and nonwoven, natural, synthetic, glass and mineral-based yarns and textiles. Since Pireta’s processing steps are all aqueous based, a key requirement is that the fabric must be hydrophilic (i.e. it must be possibly wet the fabric).

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What restrictions are there on knit pattern, knit density, yarn thickness etc.?

Subject to the comments made elsewhere in relation to conductivity and track width / feature sizes, there are no specific restrictions on the knit pattern or density, or the thickness of the yarn. The process can be applied to a wide range of knitted, woven and nonwoven textiles.

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Can dyes and protective treatments be applied?

Yes, dyes and protective treatments can also be applied to the textiles that have been functionalised using the Pireta process.

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What does the process cost?

Some set-up fees will be payable in relation to work carried out to qualify the suitability of particular fabrics, to establish the relevant process parameters and to create the print files required for Pireta’s process. In addition, fees will be payable on a per-unit basis.

The unit price to apply the process will depend on a number of factors, including the area of the conductive pattern, the size and nature of the fabric or garment, the manufacturing volume, etc. However, the process has been developed to be economical and is able to be scaled from niche market to high volume applications.

Pireta’s process is based on straightforward aqueous chemistry, utilising commercially available equipment. The process is additive – meaning minimal waste – and uses readily-available, non-environmentally hazardous and low-cost materials.

In addition to compatibility with existing electronic manufacturing processes, the technology is suitable for integration within the textile and garment manufacturing industry. The process can be operated roll-to-roll at a mill or applied later in the garment manufacturing process, either to cut fabric or to finished garments.

For more detailed and specific information about pricing, please contact Pireta directly.

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I’m a student or a private individual. Can Pireta help with my project?

Unfortunately not. Please feel free to use all of the resources available on our Web site. However, we are unable to provide samples or provide support for these types of projects. Research and academic institutions with funded projects should contact us via the form on our contact page.

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Can I obtain a sample?

Yes, standard samples can be made available. Depending on the nature of the sample, a small charge may apply for standard samples. Subject to a qualified business case, Pireta is also able to produce custom samples. Charges will apply for production of custom samples.

A price list for standard and custom samples is available upon request.

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How can I get more information?

Please contact us using:

  • Address: Pireta Ltd, New Kelvin Avenue, Teddington, TW11 0LY, UK
  • Email: info@pireta.co.uk
  • Web: www.pireta.co.uk
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