Natural Rubber / Latex – Production of Natural Rubber
Thailand, Malaysia and Indonesia are the largest producers of natural rubber in the world. Figures from the World Trade organisation posted on www.thailand.com indicate the following worldwide natural rubber production in 1998.
Natural rubber comes from the Havea brasiliensis tree, which grows in tropical regions. They typically reach 20-30 metres in height on rubber plantations, and are able to produce commercial quantities of latex at about 7 years of age, depending on climate and location. Economical life span of a rubber tree is between 10 to 20 years, but may extend past 25 years in the hands of a skilled tapper and bark consumption.
It should be noted that latex is different to tree sap.
Dry Rubber Production
Tapping Rubber Trees
Havea trees are not tapped any more often than once per day, with 2 or 3 days being the norm. In countries such as Thailand, tapping usually takes place in the early hours of the morning, prior to dawn due to the high day time temperatures and the protective clothing worn to protect against snakes etc. Also flow rates are increased due to higher turgor pressures at these times.
A tapper uses a sharp hook shaped knife to shave a thin layer of fresh bark from the tree. This exposes the latex vesicles. The cut is typically done at 25-30° to the horizontal, as this exposes the maximum number of vesicles. The same incision is re-opened the next time (typically the next day) by shaving off a small amount of bark. Virgin bark is exposed first working around in panels. The same area may be exploited again after about 7 years.
The thickness of the layer is important as too thick a slice will damage the tree and reduce its productivity and life, while too thin a slice will not produce sufficient latex. Bark is removed in a localised area for a period of time, and then a new area is tapped allowing the tree to repair itself.
The latex runs down and is collected in a cup. Each tree usually produces about half a cup of latex per day and is collected later in the day. Latex will flow for approximately 1 to 3 hours after which time the vesicles become plugged with coagulum.
Processing of natural rubber involves the addition of a dilute acid such as formic acid. The coagulated rubber is then rolled to remove excess water.
Then a final rolling is performed using a textured roller and the resultant rubber sheet is dried. Following this, the rubber is ready for export of further processing. This type of natural rubber accounts for about 90% of natural rubber production.
Natural Rubber Production
Natural rubber is used in a pure form in some applications. In this case, the latex tapped from trees is concentrated using centriguges, removing water and proteinaceous materials. It is then preserved using a chemical such as ammonia.
Applications of Natural Rubber
The natural rubber is used for making products such as:
A latex is a colloidal suspension of very small polymer particles in water and is used to make rubber.
Dipped goods (medical and surgical items, household and industrial gloves, boots, and balloons) utilize more than half of all natural latex consumed in the United States. The adhesives industry is the second largest user of natural latex in products such as shoes, envelopes, labels, and pressure sensitive tape.
Natural latex with a high solids content is also used for making molds for casting plaster, cement, wax, low temperature metals, and limited run polyester articles. Natural latex has the ability to shrink around the object to be reproduced, so that the smallest detail will be reproduced in the cast. Latex is even being used to help stabilize desert soils to make them suitable for agricultural uses.
Natural latex is produced from the Hevea brasilienesis rubber tree and is the protective fluid contained beneath the bark. It is a cloudy white liquid, similar in appearance to cow milk. It is collected by cutting a thin strip of bark from the tree and allowing the latex to exude into a collecting vessel over a period of hours.
Hevea trees mature at five to seven years of age and can be tapped for up to 30 years. Rubber yields range around a ton per acre (2.5 tons per ha) on the larger plantations, but yields four times as much are theoretically possible. Trees often are rested for a period after heavy tapping.
Natural latex was once commercially produced in the Amazon in great quantities. In recent times, production of natural latex has moved to Malaysia, Indonesia, and other Far Eastern regions. More than 90% of the total world production of natural rubber now comes from Asia, with well over half of that total originating in these countries. Other leading Asian producers include Thailand, India, and Sri Lanka. China and the Philippines both have substantially increased their rubber production as well.
Most synthetic rubber is created from two materials, styrene and butadiene. Both are currently obtained from petroleum. Over a billion pounds (454,000,000 kg)of this type of rubber was manufactured in the United States in 1992. Other synthetic rubbers are made from specialty materials for chemical and temperature resistant applications.
Tires account for 60-70% of all natural and synthetic rubber used. Other products containing rubber include footwear, industrial conveyor belts, car fan belts, hoses, flooring, and cables. Products such as gloves or contraceptives are made directly from rubber latex. Latex paints are essentially a solution of colored pigment and rubber latex. Latex foam is made by beating air into the latex before coagulating it.
The Indians of Central and South America used rubber as early as the eleventh century to coat fabric or to make into balls, but it was not until the French scientist Charles de la Condamine visited South America during
the 1700s that the first samples were sent back to Europe. Rubber was given its present English name by the British chemist Joseph Priestley in about 1770. The first modern use for rubber was discovered in 1818 by a British medical student named James Syme. He used it to waterproof cloth in order to make the first raincoats, a process patented in 1823 by Charles Macintosh. Thomas Hancock devised methods for mechanically working rubber so it could be shaped, and he built England’s first rubber factory in 1820. Also during this period, Michael Faraday discovered that natural rubber is composed of units of a chemical compound called isoprene.
During the mid-nineteenth century, Charles Goodyear discovered vulcanization, a process that retains the rubber’s elasticity under temperature changes. This process heats rubber with sulfur, which causes cross linking, decreasing rubber’s tackiness and sensitivity to heat and cold.
In 1882, John Boyd Dunlop of Ireland was granted a patent for his pneumatic tire. As the demand for tires began to deplete natural rubber supplies, the British cultivated huge rubber plantations in Singapore, Malaysia, and Ceylon (Sri Lanka). Seeds were taken from Brazil and first germinated in England and then shipped to these countries. Today, all natural rubber produced in Asia comes from trees that are descendants of the Brazilian seeds.
By the early 1900s, various countries sought ways to improve rubber compounds and to develop synthetic materials. In 1910, sodium was found to catalyze polymerization. When the Germans were cut off from natural rubber supplies during World War I, they used this discovery to make about 2,500 tons (2,540 metric tons) of rubber made from dimethylbutadiene.
During World War II, the Japanese gained control of the major sources of natural rubber in Asia. In response, the United States’ synthetic rubber industry increased its production by an astonishing 10,000%, from 7,967 tons (8,130 metric tons) in 1941 to more than 984,000 tons (1 million metric tons) in 1944. Following the war, other countries developed their own synthetic rubber factories to avoid having to rely on overseas rubber supplies.
Improvements in synthetic rubber have continued, and in addition, higher yielding hybrid trees have been developed that yield twice as much natural latex as the conventional ones. In 1971, a tree stimulant was developed that resulted in an average increase of 30% in latex production with no apparent harm to the trees.
The composition of latex sap consists of 30-40% rubber particles, 55-65% water, and small amounts of protein, sterol glycosides, resins, ash, and sugars. Rubber has high elasticity and a polymer molecular structure. This structure consists of a long chain made up of tens of thousands of smaller units, called monomers, strung together. Each monomer unit has a molecular size comparable with that of a simple substance such as sugar. Other special chemicals are used as preservatives or stimulants during the harvesting process.
Both synthetic and natural rubber production require the use of vulcanizing chemicals, primarily sulfur. Fillers such as carbon black are also added to provide extra strength and stiffness. Oil is often used to help processing and reduce cost.
Growing and processing natural rubber is one of the most complex agricultural industries and requires several years. It combines botany, chemistry, and sophisticated machinery with dexterous skills of the people who harvest the trees. Contrast this with synthetic rubber production, which involves chemical reactions and sophisticated chemical processing machinery that is automatically controlled by computers. The production of natural latex is described below.
1 Seeds from high-grade trees are planted and allowed to grow for about 12 to 18 months in the nursery before a new bud is grafted to the seedling. After bud grafting, the year-old seedling tree is cut back and is ready for transplanting. The bud sprouts shortly after transplanting, resulting in a new tree with better properties. Approximately 150 trees are planted per acre (375 per ha), which are cultivated and cared for until they are ready for tapping in about six to seven years.
2 To harvest latex, a worker shaves off a slanted strip of bark halfway around the tree and about one third in (0.84 cm) deep. Precise skill is required for if the tree is cut too deeply, the tree will be irreparably damaged. If the cut is too shallow, the maximum amount of latex will not flow. The latex then bleeds out of the severed vessels, flows down along the cut until it reaches a spout, and finally drops into a collection cup that will later be drained.
3 Tapping is repeated every other day by making thin shavings just below the previous cut. When the last scar created by the cuts is about 1 ft (0.3 m) above the ground, the other side of the tree is tapped in similar fashion, while the first side renews itself. Each tapping takes about three hours and produces less than a cup of latex.
4 A tapper first collects the cut lump, which is coagulated latex in the cup, and tree lace, which is latex coagulated along the old cut. Next, the tapper makes a new cut. The latex first flows rapidly, then declines to a steady rate for a few hours, after which it slows again. By the next day, the flow has nearly stopped as the severed vessel becomes plugged by coagulated latex.
5 To prevent most of the liquid latex from coagulating before it can be conveniently pooled and transported, the tapper adds a preservative such as ammonia or formaldehyde to the collection cup. Both the liquid and coagulated latex is sent to factories for processing.
6 To increase tree yields and reduce tapping times, chemical stimulants are used. Puncture tapping, in which the bark is quickly pierced with sharp needles, is another method that can improve productivity, since it enables the same worker to tap more trees per day.
Producing liquid concentrate
7 About 10% of the latex is processed into a liquid concentrate by removing some of the water and increasing the rubber content to 60%. This is achieved either by spinning the water out of the latex through centrifugal force, by evaporation, or by a method known as creaming. In this method, a chemical agent is added to the latex that causes the rubber particles to swell and rise to the liquid’s surface. The concentrate is shipped in liquid form to factories, where it is used for coatings, adhesives, and other applications.
Producing dry stock
8 Other rubber and field latex is coagulated with acid. A giant extrusion dryer that can produce up to 4,000 lbs (1,816 kg) per hour removes the water, creating a crumb-like material. The dried rubber is then compacted into bales and crated for shipment.
9 Ribbed smoked sheets are made by first diluting the latex and adding acid. The acid makes rubber particles bunch together above the watery serum in which they are suspended. After several hours, roughly one pound (0.45 kg) of soft, gelatinous rubber coagulates for every three pounds (1.35 kg) of latex.
10 The rubber is allowed to stand for one to 18 hours, then the slabs are pressed into thin sheets through a system of rollers that wrings out excess liquid. The final set of rollers leaves a ribbed pattern on the sheets that increases the surface area and hastens drying. The sheets are dried for up to a week in smoke houses before being packed and shipped.
Producing other products
11 To make rubber products, the mix is shaped by placing it in a heated mold, which helps shape and vulcanize the material. For more complex products, such as tires, a number of components are made, some with fiber or steel-cord reinforcement, which are then joined together. Surgical gloves are made by dipping a ceramic form into latex, withdrawing the form, and then drying the latex shape.
A number of quality checks are made after the latex is harvested. After tapping, the latex is checked for purity and other properties. After each step of the production process, technicians check physical properties and chemical composition, using a variety of analytical equipment.
The production of natural rubber has failed to meet the growing demand for rubber, and hence, today two-thirds of the world’s rubber is synthetic. However, developments, such as the invention of epoxidized natural rubber which is produced by chemically treating natural rubber, may reverse this trend. The synthetic rubber industry is also continuing to make processes more efficient, less costly, and less polluting, as well as developing new additives, compounds, and applications.
Though there are as many as 2,500 other plants that produce rubber, it is not made fast enough to be profitable. United States Department of Agriculture researchers are looking at ways to speed up the process by genetically engineering a plant to make larger initiator molecules. These molecules start the rubber-making process, and if such molecules were larger, rubber could be produced up to six times faster.
Natural rubber is obtained from the milky secretion (latex) of various plants, but the only important commercial source of natural rubber (sometimes called Pará rubber) is the tree Hevea brasiliensis. The only other plant under cultivation as a commercial rubber source is guayule ( Parthenium argentatum ), a shrub native to the arid regions of Mexico and the SW United States. To soften the rubber so that compounding ingredients can be added, the long polymer chains must be partially broken by mastication, mechanical shearing forces applied by passing the rubber between rollers or rotating blades. Thus, for most purposes, the rubber is ground, dissolved in a suitable solvent, and compounded with other ingredients, e.g., fillers and pigments such as carbon black for strength and whiting for stiffening; antioxidants; plasticizers, usually in the form of oils, waxes, or tars; accelerators; and vulcanizing agents. The compounded rubber is sheeted, extruded in special shapes, applied as coating or molded, then vulcanized. Most Pará rubber is exported as crude rubber and prepared for market by rolling slabs of latex coagulated with acid into thin sheets of crepe rubber or into heavier, firmly pressed sheets that are usually ribbed and smoked.
An increasing quantity of latex, treated with alkali to prevent coagulation, is shipped for processing in manufacturing centers. Much of it is used to make foam rubber by beating air into it before pouring it into a vulcanizing mold. Other products are made by dipping a mold into latex (e.g., rubber gloves) or by casting latex. Sponge rubber is prepared by adding to ordinary rubber a powder that forms a gas during vulcanization. Most of the rubber imported into the United States is used in tires and tire products; other items that account for large quantities are belting, hose, tubing, insulators, valves, gaskets, and footwear. Uncoagulated latex, compounded with colloidal emulsions and dispersions, is extruded as thread, coated on other materials, or beaten to a foam and used as sponge rubber. Used and waste rubber may be reclaimed by grinding followed by devulcanization with steam and chemicals, refining, and remanufacture.
The more than one dozen major classes of synthetic rubber are made of raw material derived from petroleum, coal, oil, natural gas, and acetylene. Many of them are copolymers, i.e., polymers consisting of more than one monomer. By changing the composition it is possible to achieve specific properties desired for special applications. The earliest synthetic rubbers were the styrene-butadiene copolymers, Buna S and SBR, whose properties are closest to those of natural rubber. SBR is the most commonly used elastomer because of its low cost and good properties; it is used mainly for tires. Other general purpose elastomers are cis -polybutadiene and cis -polyisoprene, whose properties are also close to that of natural rubber.
Among the specialty elastomers are copolymers of acrylonitrile and butadiene that were originally called Buna N and are now known as nitrile elastomers or NBR rubbers. They have excellent oil resistance and are widely used for flexible couplings, hoses, and washing machine parts. Butyl rubbers are copolymers of isobutylene and 1.3% isoprene; they are valuable because of their good resistance to abrasion, low gas permeability, and high dielectric strength. Neoprene (polychloroprene) is particularly useful at elevated temperatures and is used for heavy-duty applications. Ethylene-propylene rubbers (RPDM) with their high resistance to weathering and sunlight are used for automobile parts, hose, electrical insulation, and footwear. Urethane elastomers are called spandex and they consist of urethane blocks and polyether or polyester blocks; the urethane blocks provide strength and heat resistance, the polyester and polyether blocks provide elasticity; they are the most versatile elastomer family because of their hardness, strength, oil resistance, and aging characteristics. They have replaced rubber in elasticized materials. Other uses range from airplane wheels to seat cushions. Other synthetics are highly oil-resistant, but their high cost limits their use. Silicone rubbers are organic derivatives of inorganic polymers, e.g., the polymer of dimethysilanediol. Very stable and flexible over a wide temperature range, they are used in wire and cable insulation.
When people think about decorating a room, they usually visualize various accessories and small details that will make a room look better. However, when focusing just on furniture people tend to forget that the room will look plain, empty and cold no matter how much furniture and details you put in it if there is no rug on the floor. That’s why it is also important to carefully select something that will fit with the rest of the decorations and furniture. In my private house I use to own several carpets which were more for the wall then for the floor, several smaller gifts from other countries, mostly handmade. I enjoyed collecting small carpets and usually that was the only thing which I knew about them, as I said, their purpose was mainly for display. Several years back I got married, and my wife and I decided to move to a bigger establishment and spend couple thousand dollars more on the interior, which would combine my hobby with her ideas, so we ended up with five beautiful carpets. To my surprise, we found out that the padding below them plays a big role in the whole furnishing process.
When it comes to choosing bedroom carpets and rubber rug pads for them, the rule which has to be followed is this: the carpet together with the rugged pads must be large enough to outspread further than the sides of the bed at least twelve inches when it comes to twin bed and at least eighteen inches for king-sized bed. As these numbers are the absolute minimum, you can choose to go bigger, but one should know that there is such a thing as a “too big carpet” for the bedroom, meaning the carpet mustn’t cover the whole room, and that there should be sufficient area which isn’t covered with floor carpeting. If you like to inject fun and playfulness into the walls of your home, choose carpets that have unusual forms, colors and patterns.
If you would like to have your carpet as long as you can, then besides inesting in to a rubber rug pad, it would also be smart to check out from what the carpet is made of. Wool is considered to be the most durable material and most quality rugs and carpets are made from this natural fiber. In Tibet and New Zealand sheep tend to produce more lanolin, which is why most high quality woolen yarns come from those areas. Silk is often the material used to mix the design of a quality rug, because this fabric tends to reflect sunrays thus giving it a shimmering look. Cotton, grass fibers and synthetic fibers are also used to endure the lifespan of the carpet and most customers buy them for high traffic rooms, like hallways or living rooms.
Choosing a rug isn’t really that complicated, but there are several mistakes people tend to make when it comes to home décor and rugs. One of the biggest, and sometimes costliest, mistakes people do when choosing a rug is getting the wrong rug pad, either because they want to save money or don’t want to waste time on researching which rug pad is the right one for them. Using the free rug pad offered by your manufacturer instead of, say, a quality rubber rug pad, can have catastrophic effects on your carpet. In order for you to avoid these mistakes, read this article we have prepared for you and also make sure to keep them in mind when decorating your home.
When choosing the rug, you should know the appropriate size of it. A large rug needs a large rug pad which can, especially if it’s thick or made by quality natural rubber like many felt rubber pads are, often cost almost or even as much as the carpet itself. Moving on, look at the furniture in the room, and then make a decision of where you want to place the carpet. Furniture causes indentations so if your rug is underneath furniture, you need to protect your carpet with some dense rubber rug pads. The furniture should sit comfortably on the carpet, or at least with front legs of the furniture. This way, you can’t miss. Some of you may like area rugs, but if you are looking for smaller carpets, a rule of thumb you should stick to is to choose a carpet that is two feet smaller than the smallest wall of the room the carpet should go into. The thing a lot of people don’t keep in mind is just how much smaller carpets can slide, often potentially endangering the people walking over them, so you want to get a rug pad that offers great sliding protection, so you might want to stay away from fiber.
Before you choose the wall color, you should choose the color of the rug and the furniture; otherwise, you will end up running around and searching for rugs and furniture with a paint color sample in your hand. So, the best option would be to choose the furniture, then find the rug, and after you are done with this, you should decide what color the walls should be.
The basic rule of thumb when choosing a rug is usually good for a living room. As for other rooms, there are several more tips you should read before choosing a rug and, consequently, the rug pads. Do your footsteps make a lot of noise, especially for the people in the room below? If the answer is yes, then you need a rug manufactured with sound insulation in mind. Rubber rug pads with a good deal of thickness usually get the job done. Kitchen rug pads shouldn’t be fiber to prevent water pouring through the carpet and making the rug pad rot. As for the bedroom, the bed is a very heavy piece of furniture, so as previously mentioned, you will probably want to get a rug pad as dense as possible. Rubber rug pads are some of the most dense rug pads available should you pick a type with a lot of density. The most common size of bedroom rugs is 8’x10’, but if you have a smaller bedroom, a 4’x6’ will also be good. If choosing the smaller rug, you should know it doesn’t go under the bed, of course, but in front of or next to it. Remember, a cohesive space begins with good proportions, so always make sure to pick a rug of a good size.
Durahold rug pads vary in qualities and kinds. Choose yours based on if they are needed for tiled, marbled or hardwood floors. They are effective in forming a protective layer, securing both the rug and the floors. The arrangement of the strands allows them to form naturally induced vacuums between the carpets and the floors. This vacuum ensures the rug to securely stay in its place. Your house can be turned into a damage proof, waterproof and pressure resistant area. This can help you protect yourself, your loved ones and your valuables.
The overall arrangement of these durahold rug pads is adjusted to enforce its non-slip quality. Their thickness changes in inches and density in ounces depending on what extent you require the non-slip quality. This thickness is also directly proportional to whether you require the padding for an area rug or for an entire room’s carpet. Non-slip rug pads do not incorporate any glues, pastes or chemicals in their manufacture. So when installing them you need not worry about them damaging your exquisite Persian rugs and freshly polished hardwood floors. They provide a strong connection between the rugs, carpets and hardwood floors because of the detailed non-slip arrangement that has been engineered specifically.
Non-slip durahold rug pads are available in several materials; you can choose the one that will complement the overall appearance of your home. You can also make the pick depending on the floor type and the area for which the padding is required. If your rug pad has to be placed somewhere outside the house, you can go with a cheaper quality rug pad. However, for inside the house you should pick an expensive pad to make it last longer and for maximized comfort and protection.
If you have been contemplating buying durahold rug pads to line your rooms, kitchen, bathrooms and the patio, following are the options divided into two basic categories: -Non-Slip Rug Pads -Textured Rubber Non-Slip Padding
Such rug pads do not have a smooth surface that would otherwise be found on regular rug pads. These have been manufactured in such a way that the surface is comparatively coarse. This surface provides glue like action. The rough tentacle like structure of the surface clings to the rug in a strong and interwoven way. This solidifies the connection of the rug and the floor ensuring the rug to stay in its place.
The plus point about using such rug pads is that they are damage free. The union formed between the rug pads and the rug and hardwood floor is not triggered by any chemical. The frictional force is caused by the differing textures of both items in contact. This is why, whenever you remove the rug pad you will notice how well the polish of your hardwood floors was maintained. Above all, these also maintain the integrity of your expensive and fancy rugs. Their installation and removal is easy and hassle free.
If you have tiled or marbled floors, this need not be a particular choice of padding for you. However, if you have hardwood floors, you should go for this kind of durahold rug pads. These are beneficial for such flooring as they offer the protection and maintenance they require. The overall comfort of the house is also magnified. They can also assist in protecting your floors from liquids, dust and pressure. They are easy to clean and replace. Rubber Non-Slip Padding For All The Floors
Certain kind of rubber padding is positively suggested for all floors and rugs. These are rubber rug pads that have not undergone any kind of change. They are used on the basis of their original structure. They are left untreated and have no chemicals sprayed on them. They are, however, comparatively cheaper and suggested if you require rug pad for an entire room. They can also be used to pad welcome rugs and kitchen mats.
They are not specified for any particular floor. They can be used to protect cushion tiled, marbled, chipped and hardwood floors. They can easily provide you with the kind of padding you are looking for.
Therefore, if you want to cushion your house to protect your loved ones and your valuables, the above two are the finest shortlisted choices for you.
People often tell stories about their hardwood floors getting damaged due to the usage of rug pads. In order to avoid such damage, proper precautions must be taken. Moreover, the selection of rug pads must be made according to the floor types of your home.
Having hardwood floors is an investment to make for your home and in order to protect that investment; you should place rug pads underneath the rugs so that the life of your rugs is prolonged as well as the life of the flooring. Make sure that the rug pads are made up of such fibers that do not damage your flooring.
Rug pads are used to maintain your rug pads. They add softness and comfort to your rugs and keep them firm as they prevent people from slipping. They also prevent the finish of the flooring from scratches. One common mistake that people make with hardwood flooring is that when it is new, they should wait for at least two weeks for the finishing of floors drying and afterwards covering the space with furniture etc. If the floors are covered immediately after the polishing, the chemicals from the polish could react with the fibers in the rug pads which could harm the hardwood floors.
Hardwood floors could also be damaged if cheap rug pads for hardwood floors are bought on sale not knowing the material from which they are made up. Some rug pads are of low quality and could ruin the hardwood floors after a while they are placed under the rugs or carpeting spaces.
If the flooring has polyurethane and vinyl rug pads are used on it, the rug pads will stick to the surface and after a while it will leave stains which will be difficult to remove from cleaning.
There are different types of rug pads available in the market ranging from natural rubber rug pads, felt rug pads, polyvinyl rug pads and recycled rug pads. You have to be extremely careful with the selection of rug pads as there are also substandard rug pads available in the market. You must make sure that the ones that you are purchasing should be synthetic and must be replaceable through exchange if they turn out to ruin the flooring of your house.
Even hardwood flooring has three different types which are as the following:-
• Hardwood Floor (Engineered)
• Solid Type
• Hardwood Floor (Exotic)
One should not compromise on the quality of the rug pads for hardwood floors even if you have to pay a higher price for it. At least it would be more beneficial in the longer run. If a good quality rug pad is bought, it would not harm the expensive flooring of the house. However, if a poor quality rug pad is used, it could damage the flooring and you will have to spend more money on flooring afterwards.
The Economist Intelligence Unit expects natural rubber (NR) consumption growth to continue expanding in 2014-15 at an average of 3.9% as demand recovers in several major consuming countries. This follows growth of 2.7% in 2013, according to the International Rubber Study Group (IRSG). Despite the quickening pace of consumption growth, it will not be enough to eliminate the substantial market surplus in 2014-15 and we expect that prices will favour consumers, especially in 2014. That said, heavy stockpiles in China and Japan will weigh against apparent demand as consumers there will be able to displace imports by drawing down on reserves. China will remain by far the world’s largest consumer in 2014-15, but other emerging regions, such as Other Europe, North America and Latin America, will also help to support consumption growth.
We have revised downwards our forecast for global rubber production in 2014 for a second consecutive month, as a combination of dry weather conditions across South-east Asia (where three-quarters of global rubber production is located) and low prices will result in lower output and production rationalisation. We now expect output to grow by just 0.1% in 2014, largely owing to a downward revision to our Thailand forecast, before bouncing back by 3.3% in 2015. Despite the weak growth in 2014, global rubber output will still reach a record 12.1m tonnes and will mean another year of sizeable market surplus. A notable further downside risk for 2014 is the deteriorating political situation in Thailand, given the potential for rubber farmers’ participation in recent social unrest to affect supply and for exchange-rate weakness to disrupt exports.
The net result of our increases in Japanese and North American consumption, and changes to the balance of production in South-East Asia is a slightly smaller market surplus in 2014, of 268,000 tonnes, compared with 294,000 tonnes previously, and 714,000 tonnes in 2013, according to according to IRSG data. The surplus will shrink again in 2015, as growth in global consumption will outpace that in production. (Producers will generally be wary of ramping up output following a period of good supply and falling global prices.) Even with these lower surplus levels, rubber will be amply available in 2014-15 and we expect the stocks/consumption ratio to stabilise above 14 weeks, its highest level since the early 2000s. Much of the excess rubber will be held in China by the State Reserve Bureau and will therefore be unavailable to the market, helping to temper somewhat the impact of the surplus on prices. There has also been stockbuilding at the producer end, as exporters are unwilling to flood the market at a time of low prices.
Despite a small reduction in the expected surplus in 2014 as a result of dry conditions in major producers and production rationalisation, recent bearish market conditions mean we have cut our forecasts for price for RSS3, a Thai benchmark grade used in automobile tyres. We now expect prices to average US$2,455/tonne, from US$2,498/tonne previously. Given the risks to the Thai economy posed by political unrest, it is possible that the price could fall further in US dollar terms on exchange-rate effects. Prices for SMR20, a Malaysian benchmark, are expected to average M$6,560/tonne in 2014 as a whole, down by nearly 16% on 2013 (when prices already fell by 18%). We tentatively expect prices to recover in 2015, but they will still be well off their high levels of 2011.