The global demand for rubber is destined to increase, and without the latex from the rubber tree, production would stop. Science is betting on Russian dandelions
Drop by drop, the milk of Havea Brasiliensis fills a coconut or a bowl. Natural rubber is obtained from this step. It is used to make tires, rubber bands, vibration-dampers, and components for cars, medical and food products, floors, condoms, adhesives, technical clothing, and shoe soles. Without the rubber tree, many products would come to a halt. According to estimates by the GPSRN (Global Platform for Sustainable Natural Rubber) the rubber supply chain maintains thirty million people worldwide.
Global demand for rubber is set to increase, which is why sustainable management of the supply chain to preserve forests, biodiversity and the development of local communities is of primary importance. The alternative is synthetic rubber, derived from petroleum. The largest growers and producers of rubber and tires such as Bridgestone, Good Year, Pirelli, Socfin and Ford participate in the GPSRN.
At the base of its establishment there are twelve principles: the sustainability of forests; the control of water consumption; the guarantee of rights for farmers and cultivated land; traceability; equity; a commitment to education and training of the people involved in the supply chain; the promotion of anti-corruption measures; the creation of production control protocols; and above all, respect for human rights. The extraction process is artisanal — with the human hand being an essential component to this day — and depends on the resin that the plant produces to defend itself from insects, the latex.
Originally from Brazil, the rubber tree requires average temperatures of 25-30°C and a humid environment subject to at least two meters of rain per year. Considered its ideal habitat, the plant cannot be cultivated in European latitudes. Henry Wickham, an English botanist who, on commission from Queen Victoria in 1876, tried to grow the seeds of the plant in English gardens, realized that Southeast Asia could be the ideal place. The trees of the Asian plantations turned out to be productive and thus almost completely supplanted the Brazilian crops (reduced to two, three percent already in 1913). Today, rubber tree plantations are concentrated in Thailand, Vietnam, Sri Lanka, Malaysia, Indonesia, China, and parts of Africa (Cameroon and Ivory Coast).
The extraction of milk from the plant is achieved through tapping. This is done at regular intervals through a diagonal incision made on the bark of the tree from which the resin exudes for hours (up to three kilograms of latex can be drained per tree). Collected in a small container, the latex can be left to coagulate, or left liquid to be transported to the farm and later be processed (field latex) with solidifying chemical acids (such as acetic acid). The life cycle of a plant lasts up to thirty years. Solid-state rubber is palletized and sold, as is latex. This distinction determines the type of rubber that will be produced.
«Latexes in a liquid state are used in the adhesives sector to make adhesives, in the medical sector (to make, for example, latex gloves or a tourniquet), rubber bands, balloons. Then there is the regenerated leather sector, which thanks to the use of latex makes it possible to couple fabrics with leather or other materials and create new objects», explains Alberto Pancani, Elastomer Sales Manager of Resinex, a company part of the Ravago group, with headquarters in Mornico al Serio in the province of Bergamo dedicated to the sale of polymers in Europe.
«Sixty percent of solid natural rubber goes into tires, the other forty percent goes into adhesives, adhesive tapes, the footwear sector (such as shoe soles), technical or fashion-related items (the inner band for underwear and shoulder straps for corsetry). Another important sector that uses solid rubber is the automotive sector for all vibration absorption systems of body engines, in the transport sector (from railways to ships). The same is true for synthetic rubbers which have partially replaced some uses of natural rubber. 99% of the private car tire is made of synthetic rubber only. On the other hand, natural rubber is still widely used for truck, tractor and quarry vehicle tires (given its resistance to pressure and imposing weight)», explains Pancani.
Natural rubber has different price levels per kilogram: Malaysian latex (often in a higher quality) sells for $1.05, dark (i.e.,smoked) rubber for $1.23, latex rubber from $1.35 to $1.60. The cost of synthetic rubbers varies every day because it follows the trend of monomers and is based on the figures established by the Singapore stock exchange.
When it comes to the sustainability of natural rubber, we go back to planting and exploiting the plant. «All the producers we source from follow a sustainability program, both at the production level and at the social level. At the end of the plant’s life cycle, the tree is felled, and the wood is used to make furniture or to create pellets and materials for heating. In its place, a tree ready for use is replanted. Around the plantation (usually a density of five hundred, five hundred and fifty trees per hectare) schools, roads, offices and hospitals are created to guarantee a life for the plantation workers. Thousands of people work in these and are home to up to six, seven thousand people. Producers want to make people feel good because this influences production», says Pancani.
Among these, Socfin (Société Financière des Caoutchoucs) group founded in 1909 deals with the management of natural rubber and palm (from palm oil) plantations in various areas of Southeast Asia and Africa. The group’s production of natural rubber exceeds one hundred and fifty-five tons per year. At the same time, thanks to the CO2 absorption properties typical of the rubber tree, more than four tons of carbon are captured per hectare.
«The downside — natural rubber can be reused but only in a small part. The reason is sulfur vulcanization (a process to which the rubber is subjected to be more resistant and not undergo variations). After this step it is difficult to recover the material. This is granulated and pulverized but it does not necessarily mean that it will be reused one hundred percent. Unlike plastic, for example, which, if collected and available in its various compositions, has a longer life cycle», emphasizes Pancani.
Pirelli buys and uses natural rubber from Indonesia, Thailand, Malaysia, Brazil and China. One of the company’s priorities is the economic, social and environmental sustainability of the natural rubber supply chain. A commitment that began in 2017 with the Sustainable Natural Rubber Policy, designed to regulate the responsible sourcing of rubber and create a reliable network. To go fast you have to wait is the name of the photographic reportage made by Pirelli with the photographer Alessandro Scotti that features the original world around rubber. From uncontaminated nature made up of noises and silences, to the life of farmers and their relationship with the plant from which rubber is obtained.
If the use of rubber is mainly linked to the production of road tires – i.e. solidified natural rubber — it can also be used to make shoe soles. This is the case of GEA Gomma, the European leader in the production of natural para for footwear: Sole Crepe. Founded in 1952 in Vigevano with headquarters in Castello d’Agogna in the province of Pavia, the company is in the fourth generation of family management and stands out for its totally sustainable footprint.
«My grandfather, Giuseppe Bonomi, after exploring plantations in South-East Asia, decided to use natural rubber from Sri Lanka, for better performance. We work on about six hundred thousand kilos of rubber a year with a non-existent waste: all the waste is reused, even that of the shoe factories», explains Stefano Grivel, General Manager of GEA. An ecological and non-polluting manufacturing process that occurs mechanically (it does not produce fumes or vapors, dust, or slag) and without the use of additives or dyes.
«The solidified raw rubber comes in bales of twenty-five or fifty kilos. This is ground through mills and calendered through calenders. From here, sheets are obtained which are then divided into plates of various thicknesses: from two to twenty millimeters. Once the required slab has been made, it is on sale to the shoe factory that will transform it, by cutting it into a sole for shoes. The natural para is used for the classic and modern Clarks ankle boot (a former customer of theirs but that produces everything directly in Vietnam) but also for women’s and children’s shoes», Grivel emphasizes.
Recyclable and ecological, the natural rubber soles are resistant to abrasion and water, unalterable in contact with acid, alkaline or saline solutions, elastic and flexible. Sole Crepe is available in natural colors (from yellow to black) or is dyed with the addition of non-toxic coloring pigments.
What if the constant demand for rubber was no longer sustainable or if the plantations in Southeast Asia were hit by a fungal attack? Science is working on a solution starting from the Russian dandelion plant. And it could also be grown in Italy.
«Latex is produced by many plants, not only from the rubber tree. In the case of opium, for example, latex is neurotoxic to insects. Let’s think of the fig, the guayule (a bush from which it is possible to obtain latex to produce natural rubber) and the Russian dandelion», explains Paolo Facella, a researcher, molecular biologist at ENEA (National Agency for New Technologies, Energy and Development economically sustainable) and co-author of the scientific study ‘Comparative transcriptomics between high and low rubber-producing Taraxacum kok-saghyz R. plants’.
The study, published in December 2018, considers rubber from Russian dandelion latex as a valid alternative to that derived from Havea Brasiliensis. «The Russian dandelion – a relative of the officinal dandelion, the so- called dandelion – produces latex both from the roots and from the leaves and is native to Kazakhstan. The challenge is to make this plant adapt to more temperate climates, many groups work there in Europe», Facella explains.