Progress Week 8- Green Gifting Developments- Materials & Manufacturing

The possibility of using only Cork Material for the Cups was explored. having a Mono-material product is beneficial as it does away with the need for material separation during recycling as well reduce the amount of raw materials extracted and manufactured.

Top left shows Portuguese Design Company Simple Forms using both Natural Agglomerated Cork and a Cork-Rubber Composite for wash basins.

The idea of using just agglomerated cork for a product that's constantly in contact with moisture as well as the properties it must have to ensure hygiene standards was intriguing

Below are images of various cork bowls; it was found that these bowls are not dishwasher safe, and most of the time are for display use only e.g. fruit bowl.

The collection of cork vessels from Detroit designer Nicholas Stawinsky seem to be functional cups and bowls for use in a dining context, however, after email Nicholas without reply, this assumption can not be confirmed.

Without confirming any cases where cork is the sole material used as a drinking vessel, it was determined that the design of cork tea cups had to be a multi-material product.

To abolish the need for separation in the recycling process, it was decided to design the tea cup as two separate components: the cork exterior providing aesthetics, insulation and grip, and a porcelain insert that can be removed for washing.

This design concept links back to the initial inspiration Brr Mugs by Delta Faron (see bottom left in the above image).

Materials Research

Cork

•   ^expansionà^insulation
•  Sustainable (regenerates every 9 years for harvest
•  Sophisticated, natural touch, unique sensory experience
• Recycled cork
•  Natural agglomerate cork
• 100% recycled cork, biodegradable, heat resistant, local
• Plastic Inner casing

Source: Sustainable Vision 2-Cork Design, Matrec, 2012

• Cork is composed of dead cells that accumulate on the outer surface of the cork oak tree.

• An incredibly versatile natural material, cork is harvested from living cork oak trees somewhat like wool is gathered from sheep. The trees are unharmed by the process, and they continue producing cork for an average of 150 years.

• honeycomb-like structure, cork consists largely of empty space

• cork consists of irregularly shaped and spaced cells

• empty cells =(40 million per cubic centimeter),

• microscopic Bubble Wrap

•  large amount of dead-air space makes cork an effective insulation material for both temperature and noise.

• Fire retardant; no toxic fumes are generated

•  Non slip

• Flexible

• Resilient to wear

• Cork absorbs neither dust nor moisture, and it resists both rot and insects

• American named John Smith developed a technique for producing pure-cork agglomeration out of waste material by subjecting cork particles to heat and pressure without adding any binder.

• evergreen Quercus suber or the deciduous- Quercus occidentaliscork oak trees

• Portugal's cork forests are the most productive. Accounting for 30% of the existing trees, they produce half of the world's harvested cork.

• first harvest is of poor quality, and can only be used to make agglomerated cork products.

•  Production of compound agglomerated cork involves adding a binder or adhesive agent to cork granules

• Different binders are chosen, depending on the qualities desired in the ultimate product (e.g., flexibility, softness, resistance to wear). Among those frequently used are asphalt, rubber, gypsum, glue, and plastic.

Source: Made How 2013, Advameg Inc, Accessed on 29 April 2013, 

<http://www.madehow.com/Volume-5/Cork.html>

- cork life cycle, from production to recycling, is a clean one, without any by-products

- all waste from production; lower quality material or obsolete product is grind to obtain the granules from which are made recycled cork blocks

- water in which the material has to be boiled after collected is not polluted by the process; all means to work and prepare cork are mechanical based and even the dust resulting from this is used to generate electric energy.

-  present in everyday rituals and objects – from drinking vessels (which shape is directly cut off the tree) to seating benches.

-  structure and chemical composition of cork give it remarkable properties: its tissue is 89,7% comprised of an air-like gas that makes the material very lightweight (0,16g per cubic centimeter) and low density; impervious to liquids, a very good thermal insulator; chemically stable and mostly unaffected by microbial activity – highly resistant to humidity and oxidation.

- honeycomb cellular structure

•   Chemical composition:

45% suberin (responsible for corks resilience), 27% lignin (the binding compound), 12% cellulose and polysaccharides (cell wall compounds that help define cork texture), 6% tannis (compounds responsible for colouring), 5% wax (hydrophobical compounds that assure the corks impermeability), 5% ashes, among other elements like mineral water, glycerine, etc).

•   Suberin is the natural waxy substance responsible for making cork anti-allergenic (mold, mites and even termites are repelled by cork) and fire (it is a natural fire inhibitor and also does not release any toxic gases during combustion).

Suberin also prevents cork from rotting even when completely submerged under water for long periods of time.

•   The montado ensures the life of its population in areas of hostile climate and poor grounds, as well as it sustains a biodiversity greater than any other agricultural system. Therefore it has a large ecological, economical and social importance.
•   Portugal has the largest cork production (21% of national forest area) and transformation industry of today.

Source: The Home Project Design Studio 2013, Accessed on 29 April 2013,

<http://www.the-home-project.com/exploring-cork/>

The Manufacturing 

Process

• 1 Using a specially designed hatchet, the harvester slices through the cork layer on the trunk of the tree, taking care not to cut deep enough to damage the living portion of the trunk. Horizontal cuts are made at the base of the trunk and just below the lowest branches. A few vertical cuts separate the circumferential cork ring into sections of an appropriate size. Using the wedge-shaped handle of the hatchet, the harvester strips each panel of cork from the tree. On some large trees, cork is also stripped from the lower branches.
• 2 The cork planks are stacked outdoors and left to cure for a time ranging from a few weeks to six months. The fresh air, sun, and rain encourage chemical changes that improve the quality of the cork. By the end of the curing process, the planks have flattened out and lost about 20% of their original moisture content.
• 3 The planks are then treated with heat and water to remove dirt and water-soluble components like tannin, and to make the cork softer and more flexible. This process typically involves lowering stacks of cork planks into large copper vats filled with boiling water containing a fungicide. Heavy weights are placed on top of the cork to keep it submerged for 30-75 minutes.
• 4 When the planks are removed from the vat, a hoe-shaped knife is used to scrape off the poor-quality outer layer of cork, which amounts to about 2% of the volume of the plank but 20% of its weight. The planks are stacked in a dark cellar and allowed to dry and cure under controlled humidity for a few more weeks.
• 5 The cork planks are trimmed to a uniform, rectangular shape and are sorted by quality. The finest quality material will be used to make natural cork products like wine bottle stoppers. Poorer quality material will be ground and used to make composition or agglomerated cork.

Boffle corks

• 6 Cork slabs of the desired thickness are placed in a steam chamber for 20 minutes to soften them. The slabs are then cut into strips whose width corresponds to the intended length of the bottle stoppers. The strips are fed through a machine that punches hollow metal tubes through them, removing cylinders of cork.
• 7 Although some beverage bottlers want cylindrical corks, others want tapered ones. To achieve this shape, the cylinders are arranged on a slanted conveyor that carries

• 8 Both cylindrical and tapered corks are washed, bleached, and sterilized in large vats. Rotating wooden paddles continually push the corks down into first a washing solution and then a neutralizing solution.
• 9 After being dried in a large centrifugal dryer, the corks may be marked with an identifying label (with ink or a hot-metal stamp). Some are also coated with a sealant such as paraffin or silicone. Then, they are packed in airtight bags in quantities of 1,000 or 1,500; the air is removed from the bags and replaced with sulfur dioxide (SO ₂ ) to keep the corks sterile.

Agglomerated cork

• 10 Waste cork is passed through a machine that breaks it into small pieces. The pieces are washed and dried, and then sent through two successive grinders to further reduce the particle size. After another washing and drying process, the particles are screened for uniform size.
• 11 Pure agglomerated cork is formed by packing cork particles into a mold and covering it securely. Superheated steam (600° F or 315° C) is passed through the

12 Compound agglomerated, or composition, cork is made by uniformly coating the cork granules with a thin layer of an additional adhesive agent. The coated granules are pressed into a mold and slowly heated (the temperature varies, depending on the adhesive used). When removed from the mold and cooled, the blocks are stacked to allow air circulation and are allowed to season.

• 13 The agglomerated cork is cut for its intended use. For example, sheets may be cut from rectangular blocks. Or if a tubular mold was used, the resulting cork rod may be sliced into discs. A large, cylindrical block might by revolved against a knife blade to shave it into a long, continuous sheet that is rewound into a roll.

Byproducts/Waste

Cork waste generated during the manufacturing process is ground and used to make agglomerated cork products. Cork powder that is generated by the grinding process is collected and burned to help fuel the factory.

 Source: Made How 2013, Advameg Inc, Accessed on 29 April 2013, 

<http://www.madehow.com/Volume-5/Cork.html>

Recycling

-  Off cuts from cork production can me combined with granules to make lower quality cork products

-  Dust can be used as fuel to power factory

-  Water not polluted, used over and over

-  water in which the material has to be boiled after collected is not polluted by the process; all means to work and prepare cork are mechanical based and even the dust resulting from this is used to generate electric energy

-  Chemical components removed from cork during its processing can be recovered as useful byproducts and include tannin (used for curing leather), hard wax (used in products like paraffin, paint, and soap), resinous gum (helps vanish adhere to copper and aluminum), and phonic acid (used to make plastics and musk-scented toiletries).

-  Cleaned, shredded, combined with adhesive, used to make other products

Source: Cork Recycling Program 2007, Web Video of Money Wise (TV Program) News Report, Accessed on 29 April 2013, 

<http://www.youtube.com/watch?v=VztmUBKvf6I>