The Take-back of nylon carpets in the USA (Dupont)



by Walter R. Stahel
The Product-Life Institute, Geneva


The societal pressure in North America, the home market for DuPont de Nemours, is concentrated in two areas: Firstly, pressure is mounting to decrease the amount of MSW (municipal solid waste), which in North America goes mainly to landfill. Secondly, the pressure is mounting to encourage 'post-consumer recycle content' in products, thereby creating greater markets for materials diverted from disposal via landfill or energy recovery.

DuPont de Nemours is a major producer of polyamide raw materials, polymer, fibres and enginee­ring resins, but also a chemical company committed to innovation within the limits of economic feasibility. A joint research study with the U.S. EPA in 1993, recognised that the best environmental solutions come when government establishes priorities and realistic goals, and when industry accepts the responsibility of meeting them in the most efficient way, according to Paul Tebo, Du Pont's vice-president for safety, health and environment. The overall lesson from the study was that waste-minimisation assessments must often be expanded beyond their original scope. In many cases, only close scrutiny of the entire process can lead to effective action.

Polyamide is in North America the primary material in the manufacturing of carpets (including wall to wall carpeting in industrial, commercial and residential buildings). It is becoming clear that the large amount of used carpets is a ripe target for recovery, and the major source for post-consumer polyamide. Out of the 1,5 m tons of used carpet which is disposed of every year to landfills, about 1,2 m tons has nylon face fibre, polyamide 66 fibre and polyamide 6 fibre. Since the face fibre is only about half the weight of the carpet, this means a potential of 600'000 tons of polyamide fibre available for recovery per annum. The remainder of the 'nylon carpet' is 120'000 tons of backing, mostly polypropylene, 420'000 tons of filled latex adhesive, 30'000 tons of dyes, pigment, antistat and finishes. And most importantly a significant but variable amount of dirt.

"The Partnership for Carpet Reclamation" is the name for the DuPont project to recover high purity nylon monomers from this mountain of dirty used carpet. This strategy is based on an extended producer responsibility for production and take-back/recovery of the material; in addition, it accepts a voluntary partial responsibility 'from cradle back to cradle'(circular economy) for the consumer product, as half the recovered material may be from other sources (latex adhesive, backing, dirt), and may not be econo­mically re-useable.

During the initial phase of this project in the early '90s, DuPont analysed the techno-economic feasi­bility of the different options of nylon carpet recovery: mechanical recycling, depolymerization and chemical recycling. These three basic options have different costs (processing, logistics and avoided disposal costs) and different resale values for the resulting material, which will strongly influence the future development of the nylon carpet recovery.


A sustainable eco­nomy focuses on the optimisation of the utilization (or functioning) of goods and services, and thus on the mana­ge­ment of existing wealth (goods, knowledge, natural riches). The economic objec­ti­ve of such a sustainable economy is "to create the highest possible utilization-value for the longest possible period of time while consuming as little material resour­ces and energy as possible".

On one hand, a sustainable society, of which a sustainable economy is an integral part, is based on several pillars, which are summarized are here:
1. eco-support system or nature conservation,
2. toxicology (qualitative),
3. resource productivity (flows of matter, quantitative),
4. social and cultural ecology.

On the other hand, a sustainable society is based on the concept of closed loops:
A. closed material loops (recycling) and
B. closed liability loops (cradle-to-cradle product optimisation, extended producer lia­bility, product take-back).

The first (A) is a strategy that leaves the technical and organizational problem to the free market, which may work in cases where money can be made from recycling. The second (B) is a strategy of 'internalising' in the hands of the producer all external costs involved in the production and elimina­tion of a material or product, including the costs of distribution and retro-distribution (take-back). A cradle-to-cradle product respon­si­bi­lity will inevi­ta­bly question the feasibility of producing and sell­ing short-life goods. Alter­natives such as producing and selling the uti­lization of long-life goods, or selling the results of the utiliza­tion of goods rather than the goods themselves, might give the produ­cer a strategic advantage, and an eco­no­mic incen­tive to those economic actors who get the knack of it first - an increased sustain­abi­li­ty and competitiveness will directly result from this strategy.


With regard to the first pillar of sustainability, the issue of oil as a non-renewable resource is an example of science under the influence of cultural values - an issue strongly discussed in countries like India, not yet accepted in the West. Yet the cultural differences in the definition of sustainability in the case of 'non-renewable resources' bet­ween the USA and Europe might well be worth a more profound discussion (i.e. the issue of sustainable resources defined in absolute terms v. sustainable resources defined as the absence of a decrease in the known reserves).

The petrochemical industry is well aware of the toxicology issues, i.e. the second pillar of sustaina­bility, in the production process. The concept of cleaner production may well have been developed within the chemical industry, before it became one of the first concepts of industrial ecology to be studied in industry as a whole.

The issue of resource productivity, the third pillar of sustainability, has its system-inherent limitations in the case of the carpet industry. The most efficient solution, the zero option (not to have carpets), is in modern construction often a false solution - in contrast to older buildings with their wooden floor boards. The strategies of a longer utilization can primarily be applied by installing high-quality carpets which can easily been cleaned, in some instances also by using carpet squares that can easily be exchanged in case of local damages (wear and tear and other causes). The re-use of car­pets is mainly limited to carpet squares used in e.g. exhibition halls. Re-using the material of nylon carpets for other purposes, as it may make sense for natural materials such as the re-use of wool in agriculture (closing the natural cycle), is less an option. Strategies of a more intensive utilization are again normally not feasible in the case of carpets.


A strategy of closing both loops, by re-take and re-cycling the product, is therefore probably the best available environmental strategy for nylon carpets, i.e. limiting the envi­ronmental impairment. If oil is considered a non-renewable resource, it also has a beneficial impact on the first pillar of sustain­ability. The strategy of 'Re-take and Recycling' thus turns a thinking in terms of a linear economy, where materials as well as pro­duct responsibility passes from the producer to the con­su­mer at the point-of-sale, into a more sustain­able thinking in economic loops. The following definitions are included for clarification:

RE-CYCLING means closing the material loops, in order to diminish the envi­ron­men­tal impairment at both extremes of the linear economy, i.e. in order to reduce resource depletion and waste volumes. In many cases, recycling will, how­ever, not be economically viable and needs to be accompanied by an obli­ga­tion to retake.

RE-TAKE means closing the product respon­sibi­li­ty loops with a re-use of the waste product at its highest economic value. Re-take impo­ses a product res­pon­sibility on manu­facturers, importers, vendors and users "from cradle back to cradle", and thus includes the internalisation of re-use/recyc­ling and disposal costs. In order to ensure this re-use, resale often needs to be accompanied by an obligation to re-use/recycle.

RE-USE means the search for the highest possible economic value in re-using goods, com­ponents and materials - durability is a result of the capability to re-use goods and com­ponents. The require­ments of re-use need to be taken into account in product design (mo­dular system design, common­ality principle); the (voluntary or mandatory) incentive for this is re-take.

In order to successfully implement a strategy of re-sale and recycling for a material, a company has to tackle an impressive number of problems. The technical problems include the development of a raw material of a sufficiently high quality (nylon as an 'engineering plastic' fulfils this requirement) to enable recycling, as well as developing the appropriate recycling processes. The commercial problems include the establishing of a retro-distribution system, which may not be the same as the distribution system, as well as a re-marketing strategy for the recycled material.

From an techno-economic point of view, a choice has to made between the techni­cal feasibility of the different options of recycling (mechanical recycling, depolymeriza­tion, chemical recycling), and the trends in future logistics costs as well as the future value in re-marketing of the recycled materials from this different technical options.


At first sight, closed responsibility loops seem to violate the traditional "task defi­nition" in the economy: indus­try produces efficiently, consumers use quickly, the state disposes efficiently. Strate­gies to close the product responsibility loops, such as the voluntary or mandatory take-back of consumer goods or their raw material by the producers, impose struc­tural changes and are thus more difficult to implement than the 'delegated' recycling of mate­rials (e.g. Duales System Deutschland). However, as these strategies are based on innovative corporate approaches, they are highly competi­tive as well as sustain­able, and will become even more compe­titive as the economy develops. Further­more, future technical inno­vations can be expected in this field towards technologies enhancing the use of re-manufactured materials, components and goods, as well as com­mer­cial innovations to keep costs for re-take low. [Interface Corp., a major carpet manufacturer based in Atlanta, GA, has since come up with its own strategy to take back carpets and recover the Nylon through a mechanical recycling process].

The techno-economic optimisation mentioned above results in a 'cradle and return to cradle' produ­cer responsibility for the material, and a gradual adaptation of produc­tion and distribution systems; in the future, it could also lead to a strategy of leasing the material ('rent-a-molecule'). This philo­sophy is also expressed by the name of the new game 'Partnership for Carpet Reclamation'. It was developed in several phases start­ing with collection, to mechanical recycling, depolymerization and chemical recycling, with trials beginning in 1991, running at full scale in 1995.

In industrialized countries, re-take and recycling may create a problem of oversup­ply, if the total market volume does not grow in line with the recycling capacity. Produc­tion plants may then have to be replaced by recycling plants - a uncommon thought for any investment manager. But this situation would also enable DuPont to reduce its dependence from the raw material suppliers (oil companies), as well as its dependence from the price of crude oil and any future eco-taxes (CO2-taxes, carbon taxes etc.) [DuPont has since sold its fully owned oil company CONOCO]

The situation in many third World countries is radically different. They will continue to experience a strong demand for basic materials for the building up of their infrastructure, and will continuously suffer from a shortage of affordable resources and goods, including food, shelter, and infrastructure and servi­ces for health and educa­tion. Transfer­ring the surplus production plants of good quali­ty from industrialized to third World countries may be a solution to both problems.

Also, the industrial structure for manufacturing and re-manufacturing activities may have to be unified, and regionalized in order to be closer to the new raw material markets, i.e. the installed base. This could mean smaller manufac­turing/recycling volumes and appropriate technologies. It is also feasible that an incentive will be offered for the use of standardized materials easier to recycle (choice of fibres and colours).

However, all these issues are compatible with the basic DuPont corporate philosophy of mastering the technology from crude oil to the fibre, and of being a successful player in the free market economy, independent of any state subsidies.

Recycling is a necessity in order to reduce resource depletion and post-consumer waste volumes, which are affecting the natural eco-system and the toxicology pillar of sustainabi­lity. Recycling has, however, no influence on the flow of resources through the point-of-sale in the economy. Products will increasingly by made of recycled mate­rials which can again be recycled - such as nylon.

The trend in the economy towards a more sustainable society and functional econo­my has started some time ago, yet most experts are unaware of the poten­tial­ly fundamental change that the signs on the horizon indicate. A pro-active policy such as DuPont's with the 'Partnership for carpet reclama­tion' relieves the company from anxiously watching the general development, and provides a chance for securing a leading role in the transition towards a more sustainable economy.


'Prevention is cheaper than cure', an article in the Financial Times by Frank McGurty on the changing US approach to pollution control.

Polyamide 66 and 6 chemical recycling, paper by Dr Roger A Smith and Dr Brian A Gracon, E.I.DuPont de Nemours & Co. Inc, Wilmington, Delaware, USA.