The Origins of Cork

Cork, the raw material that has positioned Portugal as the world leader of an economic sector, is produced by the cork oak tree, or Quercus Suber, which is found throughout the entire country, with greater predominance in the South, and a lifespan of around 200 years.

It is believed that the original point of dissemination of this tree was the shore of Tirreno, in Western Italy, around the Cenozoic era. The tree then spread further West, having settled in Portugal, in the Spanish regions of Extremadura and Andalusia, on the Mediterranean coast of Morocco and also, although less abundantly, in Sicily, Calabria, Argelia, Tunisia, Sardinia and Corsica.

Throughout History, there have been attempts to plant the cork oak tree in other continents including America and Asia; but even though some of these regions possessed the ideal climate for it to flourish, these attempts were not fully successful. Consequently, it has become increasingly apparent that the cork oak tree has chosen to keep the Mediterranean as its exclusive address.

Before Christ, numerous civilizations were already aware of cork’s potential. There are historical records of the usage of cork in several everyday objects around the Mediterranean sea.

In Ancient Egypt, for instance, cork was applied in nautical and fishing tools, as well as in sandals – which still happens to this day. Ancient Rome also valued the numerous potentialities of this resource: Romans applied it in rooftops and ceilings for its thermal insulation properties, as well as in pitchers, as a sealant.

Throughout the Middle Ages, monks relied on cork for temperature maintenance and protection by applying it on the walls of their bedrooms. During the 16th Century, this natural resource was used in many Portuguese ships; since the beginning of Space Exploration, cork has been the insulation solution elected by NASA and by the European Space Agency (ESA), including space shuttles and rockets for an array of programmes and missions, such as Apollo XI, which took the first Man to the moon.

Over the last decades the potential of cork has multiplied, expanding into new territories and applications through a development process heavily promoted by the research and investigation efforts of companies like Corticeira Amorim.

Characteristics

Cork is the outer shell of the oak tree, and is a natural and renewable plant-based organic fabric. In fact, this bark is regenerated by the oak tree after being extracted, meaning that cork extraction is harmless to the tree, and even contributes towards its vitality. Furthermore, cork can also be fully recycled and is completely biodegradable.

Around 45% of cork’s chemical composition is suberin, a component that provides this material with considerable elasticity. The remainder is lignin (27%), a macromolecule with insulation properties; polysaccharides (12%), that give cork its texture; tannins (6%), which are responsible for its colour; and ceroids (5%), that guarantee impermeability. This combination allows cork to possess a unique set of characteristics.

  • Impermeability
    The presence of suberin and ceroids in the cell walls makes cork an almost completely impermeable material to both liquid and gas. This resistance to moisture also enables cork to age without deteriorating.
  • Thermal and acoustic insulation
    Cork has low conductivity to heat, noise and vibration because its gaseous components are enclosed in small and impermeable compartments. These groups are isolated from each other by a water-resistant substance, lowering conductivity levels, which in cork are far inferior to those in other materials, making it an excellent resource to control noise and temperature variations.
  • Resistant to fire and high temperatures
    Cork is a fire retardant. It burns without forming a flame and does not emit toxic gases during combustion. Because of this, montados (the cork oak tree forests) are relevant in the fight against the spread of forest fires within their ecosystems.
  • Friction resistance
    Cork is resistant to abrasion and has a high friction coefficient. Its cellular honeycomb structure gives it a high resistance level to impact with other materials. This feature is greater in cork than in any other solid surface.
  • Elasticity, compressibility and resilience
    Cork can be compressed up to half of its volume without losing flexibility and is able to recover its original shape and thickness once decompressed. If compressed on one side, cork does not increase in volume on the other, which makes it an adaptable material even in contexts with variations in temperature and pressure.
  • Hypoallergenic
    Cork does not absorb dust, which makes a good ally in the prevention of allergies, considerably reducing risks for asthma sufferers. Its unchangeable constitution also makes it a highly reliable material.
  • Comfortable and soft to the touch
    Despite its irregular texture, cork is soft and flexible, making it pleasant to the touch. Today there are countless types of finishings for cork, meaning that there are less rugged as well as soft cork solutions at our disposal.
  • Lightweight
    Around 60% of cork’s composition is air, which makes it weigh only 0.16 grams per cubic centimetre.

Uses and Applications

Highly conscious of the endless possibilities of cork, a natural resource which is impossible to be artificially replicated, Corticeira Amorim has been developing a large and diversified portfolio of products and applications for this material. The fact that cork carries an unusual set of characteristics – from being extremely lightweight to its capacity for thermal and acoustic insulation – has allowed it to become a truly valuable resource for several national and international industries.

Naturally, its most widely recognised use is for cork stoppers; however Corticeira Amorim’s investment in research, development and innovation has effectively transported Portuguese cork into many other highly diversified areas and sectors, including railways and dams. As such, the cork transformation industry is in constant reinvention due to this material’s intrinsically chameleonic personality.

Among the several possible uses are solutions for:

VINICULTURE

Cork and Wine

It is to wine that cork is generally more associated. The use of this material as a sealant for wine-transporting recipients dates back to the third century b.C., but it was not until the 17th Century, through the work of monks such as Dom Pérignon, in the Champagne region, that what is now a direct link between these two universes was established. Celebrated for the wine they produced, but unhappy with the sealants used at the time, they looked for a more stable solution, that would stay still in the bottle and not interfere with the wine’s conservation. The winning option was cork – and the wine sector has stuck to it ever since.

Cork stoppers

Cork is particularly successful in this field due to its complex structure, which no man-made technology has been able to reproduce. The fact that it always returns to its original shape after being compressed allows cork stoppers to adapt to the bottleneck and keep the wine perfectly sealed. Since a vast part of the material is made up of gas, cork stoppers also allow small portions of oxygen to permeate, a vital element for the wine’s healthy evolution. Cork stoppers also protect wine from temperature variations and environmental contamination and prevent deterioration.
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AEROSPACE INDUSTRY

Thermal Protection Systems

Corticeira Amorim has been a partner of NASA (National Aeronautics and Space Administration) and the ESA (European Space Agency) since the early days of space exploration. The company has developed several cork-based solutions for temperature reduction and maintenance in spacecrafts. In the 1970’s, the NASA Viking Project used cork for the exterior of rockets, implemented to resist friction and high temperatures, and thus protect astronauts from the extreme conditions experienced during the penetration of the atmosphere (temperatures can reach up to 1500ºC).

Part of the vast Ariane Rocket family, Ariane 5 was launched between 2005 and 2015 by the European Launch Consortium, and relied on cork applications for both thermal insulation and ablation performance. Similarly, Vega, an expendable launch system that was launched into space in 2012 by the ESA, had cork placed on the nose cone and other temperature-sensitive areas to prevent overheating.

Cork used on ablative thermal shields. Vega Rocket © 2017 European Space Agency

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SOUND ENGINEERING

Cork and Acoustics

Cork is often used in sound studios and music rooms due to its acoustic insulation properties. It can be applied on the floor, on the walls or the ceiling, and can be either visible or hidden under other materials. It makes for an extraordinary difference in terms of preventing high noise levels from seeping through.

As a means of highlighting this particular virtue of cork, Corticeira Amorim has developed the Acousticork business unit, which is dedicated to applying cork-based materials in construction projects that aim to decrease the sound impact of their use. The application of cork solutions in the construction of large-scale buildings such as hotels, shopping malls, gyms and subterranean parking lots also ensures vibration reduction and more stable temperature levels.

Hotel Four Seasons, Bangkok © Country Group Development Public Company Limited

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DESIGN & ARCHITECTURE

Metamorphosis, Materia, the Serpentine Pavilion and the Lisbon Cruise Terminal

The disciplines of design and architecture have also benefited from the unique characteristics of cork, while the development of projects in these areas has also been instrumental for the discovery of alternative uses for this natural material, thus creating a symbiotic and reciprocal relationship.

The Metamorphosis project, which resulted from a partnership between experimentadesign and Corticeira Amorim, brought together 10 renowned architects and designers – Alejandro Aravena, Álvaro Siza, Amanda Levete, Eduardo Souto de Moura, Herzog & de Meuron, James Irvine, Jasper Morrison, João Luís Carrilho da Graça, Manuel Aires Mateus and Naoto Fukasawa – to explore the potential of cork through pieces that use this material in an innovative way. The final result comprises an impressive variety of works that uniquely represent the advantages of a creative approach to the different application possibilities of cork.

Cork Space by Manuel Aires Mateus (2013) © Pedro Sadio & Maria Rita @that image

Materia is a collection of 24 exclusive design objects, made of cork, launched by Corticeira Amorim and curated by experimentadesign. Created by 12 renowned international designers and design studios, its original aim was to raise the profile of cork and conquer new territories and diverse audiences, and it was created at a time when the role and relevance of cork as an ideal material for product design had not yet been fully explored. As a result of the most advanced production technologies, this new line of objects was devised for everyday use and benefited from the unmatchable properties of cork. Featuring several typologies, it fuses innovation, functionality and an understanding of the necessities of modern-day life.

Materia products © Pedro Sadio

In 2012 cork was the protagonist of one of the most internationally recognized annual landmarks in the field of architecture, having been the main component of the Serpentine Gallery Summer Pavilion of that year, in a public intervention within London’s Kensington gardens. The use of cork in this 80m² circular structure conceived by Herzog & de Meuron and Ai Weiwei contributed to its immersive component through the inherent characteristics of this material — its evocative smell, inviting coloration, soft texture and thermal isolation, which created a sense of coolness and tranquility during the height of summer.

Serpentine Gallery Summer Pavilion by Herzog & de Meuron and Ai Weiwei (2012) © Iwan Baan

Designed by Portuguese architect João Luís Carrilho da Graça, the new Lisbon Cruise Terminal involved Corticeira Amorim, Secil and Coimbra University in the development of a new type of structural lightweight white concrete, incorporating cork, used in the building’s facades. This new compound made it possible to reduce the weight of the building’s structure, while maintaining its resistance, and also improving its comfort and energy efficiency due to cork’s thermal capacity.

Lisbon Cruise Terminal, by João Luís Carrilho da Graça (2017) © Pedro Sadio

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INFRASTRUCTURES

Construction and Energy

Large-scale construction enterprises, including bridges, aqueducts, dams and airports, need to ensure that the contraction and expansion resulting from thermal variations do not damage structures and materials. Cork is a great ally in this goal, and Corticeira Amorim has created a range of products that are conceived to be applied to concrete junctions: Expandacork.

Dam with cork infills

The renewable energy sector also relies on cork to enhance the operation of its structures. For instance, eolic energy turbines often include cork solutions in order to absorb vibration, which help to maintain a stable temperature and prevent condensation on the blades, allowing them to rotate faster and improve their general performance.

Eolic turbines with cork applications

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FLOOR AND WALL COVERINGS

Domestic and Industrial Cork Applications

The characteristics of cork make it ideal for use in floor and wall coverings. For this purpose, innovative solutions are developed, combining cutting-edge technology with the incredible natural properties of cork. The results are pavements and coverings that guarantee an excellent technical performance, which allows their use in both residential and commercial spaces, and that benefit from the incomparable properties of cork: reducing the sound of steps up to 53%, creating less noisy environments; keeping an optimum temperature all year round due to natural thermal insulation; increased comfort and resistance to impact.

The incorporation of this unique raw-material and the ecological production process associated with these products results in various solutions with a negative carbon footprint, thus reducing the potential of global warming.

By combining traditional production methods with advanced technology, Corticeira Amorim develops unique products that go beyond the traditional visuals of cork, leading to a wide range of realistic looking finishings that include wood and stone.

Cork flooring on a residential area

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SPORTS

From Surf to Soccer

Cork is also widely useful in the sports sector – and not only on land! In fact, thanks to its shock absorption, lightweight, flexibility, durability and resistance to water and heat, this natural resource can contribute efficiently to improve surfboards, kayaks and boats.

In fact, since 2013 world-record holder Garrett McNamara has been surfing the massive waves of Nazaré with a Mercedes surfboard that emerged from a partnership between the German company and Amorim. The surfer trusts this board thanks to cork’s impact reduction properties.

Garrett McNamara Surf Board

Cork is also a good solution for both natural and artificial turf infill. The use of cork improves sporting performance and offers a natural and sustainable alternative option to artificial turf. As a waterproof, non-toxic, shock-absorbent and long-lasting material, which is also able to maintain temperatures below those of more traditional materials, thus decreasing the need to water turf fields, cork proves to be a natural ally both for training and maintenance.

Cork-based artificial turf infill © Ricardo Gonçalves

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BUILDING THE FUTURE

Biobuild, Quickbuild and Osirys

With Biobuild, Corticeira Amorim has been developing a set of avant-garde and sustainable solutions for buildings. This initiative includes the development of thermal insulation panels that provide a real temperature separation between interior and exterior; covering systems for façades; removable options for space division and suspended ceiling systems.

Through the Quickbuild project, Corticeira Amorim is developing and presenting an array of construction options that stand out for their speed, readiness and sustainability. The main focus of this project is to offer the option of building an entire house. Through a modular construction system, it is possible to obtain a ground-floor building, a 2 bedroom prefabricated home, that is sustainable and operates according to the “total life cycle cost” concept. The fabrication process of the modular construction is versatile, allowing for some parts to be produced in Portugal and the implementation of finishings directly onto the house. Adding to this housing system, the Quickbuild project also develops a digital app dedicated to the design, planning and budgeting of each of these constructions.

Osirys is an international project created by a consortium of companies in which Amorim’s Cork Composites unit is included. The main goal of this project is to provide improvements for the energetic efficiency of buildings, as well as to achieve better indoor air quality. Designed to be applied either in private residences or in public spaces such as restaurants, the solutions developed by this consortium range from the rehabilitation of facades to the application of ecological, cork-based inner walls in all types of buildings. Through the Osirys programme, Amorim’s Cork Composites and Insulation units have been developing cork panels with improved fire retardant and antifungal properties; and creating new cork-based sound absorbent materials.

Osirys project

For more information, please visit amorim.com.