Earlier this quarter, colleague Anne-Marie Conn attended TechTextil North America (Atlanta). Below, she provides a patent law perspective on one of the most talked-about aspects of the industry at TT2023: advanced functional fabrics.

Patent Protection for Advanced Functional Fabrics

“Advanced functional fabric” (AFF) is a term often used as a catch-all for any textile that has properties unlike those of traditional textiles. Thus, it can be used quite loosely to encompass a variety of exotic materials. As these represent the bleeding edge of textiles innovation, they are often eligible for patent protection.

This brief article looks at three of the key considerations in patenting AFFs:

1. obtaining a patent for applying a known technology in a new field, or combining known technologies from different fields;
2. functional language in patent claims; and
3. how to comprehensively protect a complex (multi-part) product in all of its aspects.

Each of these areas (i) to (iii) is given colour with its own unique case study in the field of AFFs.

Synergy: AFFs that combine different technologies from two technical fields

Example: conductive yarns for elastic textile sensors

The inventive concept of an AFF often lies in combining technologies from two different fields or applying a known technology to a new field. One example is sensor textiles, which can be made through various combinations of wires and yarns. Elements suitable for sensing, e.g. fine copper wires, are evidently well known in their field. It goes without saying that yarns are also conventional – and in many cases, ancient – in the textiles field.

A challenge with inventions that apply a known technology in a new field is convincing the various Patent Offices (e.g. the European Patent Office/ EPO; Korean Patent Office/ KIPO; Chinese Patent Office/ CNIPA; or the US Patent Office/ USPTO) that the invention involves a so-called “inventive step”. Even if an AFF is, strictly speaking, a brand-new product, the Patent Offices will be looking for a clever or surprising technical effect that makes the product not only novel, but inventive. If two technologies were previously known in their separate fields, and the invention lies solely in combining them, it can be difficult for some patent Offices to accept that this is truly inventive, even if a real brainwave was involved for the inventors. Often, the objection of a “mere aggregation of features” is raised. The EPO, for example, will analyse whether the relationship between the features is one of “functional reciprocity” or that they show a combined effect beyond the sum of their individual effects. The UK IPO similarly looks for a synergy amongst features.

To illustrate this point with a relatively simple example, in the mentioned field of sensing textiles, a core of conventional elastic yarn (e.g., yarn comprising nylon) can be sheathed in loosely-attached coils of conductive fine wire. The resulting product is conductive but retains elasticity because adjacent turns in the coil can move apart whenever the central yarn stretches. In contrast, a core of wire encased in a polymer sheath may well be conductive but will be inelastic, limiting its applicability as a conductive yarn in sensing textile applications for which stretch is required.

An argument can be put forward for the elastic sensing yarn, that synergy lies in the wire helices stretching simultaneously with the elastic yarn. A resultant textile can stretch yet still conduct electricity, making it suitable for wearable sensing products. Core-sheath structures having a straight length of wire surrounded by a sheath of polymer are unable to provide this functionality. Although this is a relatively basic example, it showcases the principle that the presence of a synergistic effect can make a combination invention patentable.

Functional language in patent claims

Example: anti-brittleness measures for knit nylon-containing military textiles

Especially in the chemical field, the European Patent Office may raise objections when parts of an invention are defined in terms of the function they perform, instead of their physical components or chemical make-up. For quite literally “functional” fabrics, this can be a tricky area to navigate.

Such an objection is likely if the EPO considers an invention is being claimed in terms that amount to claiming the underlying problem the inventors were seeking to solve.

As an example, take anti-brittleness measures for knit nylon-containing textiles in military products exposed constantly to sunlight. An invention may lie in the discovery of especially good UV protection when a particular density of knit loops is combined with a metal oxide sheath deposited on the yarn to a particular thickness. Yet a patent claim defined just by the desired result – along the lines of “a thick enough coating and a dense enough knit to prevent brittleness” – is unlikely to succeed. Specific features, e.g., a numerical range for the density of the knit in gsm (which may depend on the pattern, e.g. weft knits vs warp knits) and a range of nm or µm thicknesses for the metal oxide, may help concretise the invention in the claims. It will also be important to include in the Examples section of the patent application a range of different products that achieve the desired effect across the entire range, showing the inventive contribution and the scope of protection sought are commensurate with each other.

A balance is required to achieve a commercially useful scope of protection without running afoul of the EPO’s aversion to claiming the underlying problem the inventors were seeking to solve. How to find this balance should ideally be considered in detail before filing a patent application, via dialogue between the inventor and their patent attorney; the latter should have the right technical background (here, an appropriate technical background would be chemistry or natural sciences, even better an attorney with experience of textiles from a chemical angle). Careful planning leads to a smoother, more cost-effective patenting process, not only in Europe but in other jurisdictions, particularly those (China/ CNIPA being a good example) with law and practice similar to that of the EPO.

Complex products

Example: foamed yarns in 3D knits for medical cushioning

To shut competitors out of an area of commercial interest, it is important to seek protection not only for an end product, but for processes and sub-processes of manufacture; and parts and sub-parts of the product, if at all possible. It helps to consider where functional textile products might be manufactured, including whether components of a complex product might be made in separate countries and shipped off for assembly and/or finishing processes such as the application of coatings.

As one example, take a foamed yarn for a 3D knit used in medical cushioning applications. The yarn might be formed from a novel and inventive pre-foam composition, containing polymer and other components. That should be protected in its own right, to guard against unauthorised production and sale of the composition itself. The manufacturing process for that composition could also be protected. Then, a process for foaming it and forming it into a yarn should be considered for protection. Could those two steps be separately protected? Would there be value in doing so? Or do the two steps happen at once, e.g. through foaming simultaneously with extruding the yarn? Is it possible to claim finishing steps separately (for example, a claim of finishing an obtained unfinished product)? One must then, of course, claim the yarn itself; and consider protecting complex products containing the foamed yarn, such as the 3D knit products. These could be defined relatively loosely, for example as “a cushioning element comprising … [the yarn]”, rather than limiting specifically to the 3D knit per se.

It may be appropriate to protect all of these aspects via a single patent application. Yet that may not always be possible, e.g. in Europe upon encountering a so-called “unity” objection or an objection as to “multiple independent claims”; or, e.g., in the US due to so-called “Restriction Requirements” at the USPTO. Filing a first application to all of the subject matter, then branching off “divisional” and/or “continuation” applications, may be helpful. A patent attorney having a good working knowledge of several different jurisdictions and the capability to manage portfolios of inter-related patent applications will be able to advise. At Abel & Imray, we work with attorneys specialised in an array of jurisdictions and are comfortable drawing together the requisite expertise.

Conclusion

Bringing together a technical and legal team with the experience and insight to optimise patenting AFFs can be challenging. That’s where we come in. Whether your focus is on polymers, fibres, yarns, fabrics, adjuncts (e.g. dyes) and/or other aspects of textiles, our attorneys are well-placed to protect your brand and innovation.

Our clients in the textiles sector include those at the level of multi-national corporations; we are at ease handling large and established patent portfolios. We also cater for other business sizes, from established mills to start-ups and university spinouts. We will carefully consider the nature of your business and help determine the right IP strategy for you.

If you have any queries about this article and/or you are interested in protection for an AFF (or other textiles) invention, please get in touch with your usual contact at Abel & Imray LLP or reach out to the author at: anne-marie.conn@abelimray.com.