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Overview of the Various Alternative Uses of Sisal

Gordon Mackie[8]
Northern Ireland

Before considering the future for sisal growing and sisal products, it is appropriate to look briefly at the history of the use of sisal and similar hard fibres, (excluding coir and abaca) over the past century. From Figure 1 we can see that something very dramatic happened in the late 1960's. This was the availability of low cost synthetic competition in the form of Polypropylene slit film twine. Its use as a sisal substitute in cordage started to take off around 1970 and its growth has scarcely paused during the past thirty years. I have little doubt that this pattern will continue during the next decade, as projected in Figure 2.

Figure 1: Production of sisal and other hard fibres

Figure 2: PP and HDPE world consumption in ropes and twines as monofil or slit film

Polypropylene, having penetrated sisal's core markets in agricultural twine and cordage, in effect capped the price possibilities for sisal. This, in turn, forced raw sisal prices down. In Figure 3 we can compare the CIF Europort prices over the last couple of decades. In current US $ terms the price of East African UG tends upwards. The price of Brazilian number three fluctuated between $400 and $660. In terms of constant US 1995 dollars one can see that both grades suffered significant long-term declines.

Figure 3A: Sisal prices (nominal)

Figure 3B: Sisal prices (deflated)

There might be a 10 or 15 percent price recovery in constant 1995-dollar terms over the next ten years, but more probably the effects of inflation will cancel out any higher price expressed in current US dollar terms. African grown sisal, which is on average of better quality, should retain its historic price advantage over Brazilian sisal. Overall, world sisal output has closely followed world demand for agricultural twines and cordage, as shown in Figure 4.

Figure 4: Sisal production and twine output

Will there be any relief for sisal growers or users caused by higher PP resin prices or possible shortages? It seems most unlikely. Figure 5 shows African UG sisal prices in current US Dollar terms compared to PP resin prices. I anticipate that both will tend to move together. Figure 6 shows the same data, but this time expressed in terms of constant 1990 US Dollars.

Figure 5: UG sisal and PP resin prices in current US dollars

A shortage of PP is almost out of the question no matter what happens to the world price of oil and gas. World PP production capacity will reach 53 million tons by 2010, with an expected actual output of around 47 million tons. PP is used in a wide variety of textile applications ranging from carpets, non-wovens, sacks and bags to cordage. Figure 7 distinguishes the amount used for sisal and jute substitution in the form of 'slit film' compared to the amount of resin used for conventional round fibre textile use or in non-wovens.

Figure 6: UG sisal and PP resin prices in constant 1990 US$

Figure 7: World PP by market area, 2000 and 2010

Only a minority of PP resin, about 20 percent, goes into textiles of all sorts. An even smaller proportion, 7 percent, goes into slit film yarns and twines. Finally overall only 1.7 percent of the world output of PP resin ends up being used to substitute sisal products in ropes, cordage or twines.

Well, that is the bad news for sisal's prospects. Is there any good news? Not a great deal must be the answer, but the decline in sisal output and use will, I believe, continue to be a relatively gradual affair, rather than suffering a dramatic collapse. In Figure 8 I have detailed sisal fibre production in the four main producing areas - Brazil, East Africa, Mexico and China with others, (mainly central and south America). This figure shows my expectation of production volumes over the next decade. Volumes are all trending down, with the exception of some possible, rather marginal, improvement in eastern and southern Africa.

Figure 8: World sisal production by country

Climate change is a wild card in any attempt to forecast long term output of sisal or any other agricultural crop. However sisal is quite drought resistant and is grown on poor soils in drought prone tropical regions. This ability should help it to survive, if in future, droughts tend to be longer and more severe in Northeast Brazil, or in east Africa. In China on the other hand some sisal has been planted on relatively rich soils capable of irrigation, there future demands for increased food production could squeeze out the replanting of sisal in such areas.

Where does all this leave sisal in terms of end use consumption? I have, rather arbitrarily, divided my analysis into two main categories - "Major" and "Minor" end-uses. Figure 9 shows the major end uses - few surprises here, agricultural twines, ropes and cordage and sacks and bags, all shrink in volume. The prospects for woven sisal mattings, shown at the bottom of the table, do seem to be holding firm or even improving slightly. Sisal carpets and or mattings have been well represented at the last three Domotex Carpet Shows in Hanover, and I expect to see a similar picture there next month.

Why should sisal mattings be holding up against the overwhelming tide of conventional floor-coverings made from nylon, PP and wool? Is it all to do with the ecological movement and consumer interest in natural fibres? Hardly, only 10 percent of sisal matting are sold to specialist "Eco" outlets. The bulk goes as 'niche market,' hard wearing imitation 'hair-cord' floor-coverings for exhibitions and home furnishings. Sisal is sold as an attractive natural fibre floorcovering in its own right. Figure 10 shows the countries where sisal mattings are produced and an estimate of output in square metres. This year in total, I calculate, around 9 million square metres will be produced and sold. This will use about 18 000 tons of raw sisal. Figure 11 summarises the consuming markets, primarily in the EU, with the USA and rest of the world sharing the remainder.

Although the strictly " Eco" market is not dominant in the case of mattings, the fact that sisal carpets are considered nature friendly and a renewable resource is an important consumer marketing consideration. I believe the home and shop sales of parcelling twine made from sisal would also benefit from this user perception. A targeted marketing campaign aimed at end use consumers in Germany and the West Coast of the USA will either confirm or refute this point of view. To place a 50 gram ball of sisal twine into one household in every ten in the European Union and the United States would require 10 000 tons of twine, and is a market size equivalent to half that of mattings.

Figure 9: Major usage of sisal and hard fibres

Figure 10: Sisal floor coverings output in year 2000

Figure 12 shows the prospects for what I have termed "Minor" end uses for sisal. This data may prove more controversial as market information is not easy to get hold of. One rather striking event was a collapse in the use of sisal for cellulose pulp in Brazil during the mid 1990's. This event seems to have been entirely price related. Sisal yields two thirds pulp by weight, and it costs circa US$200 per ton to convert into pulp, so if traded cellulose pulp is selling at US$620 per ton, raw sisal can earn around US$350 per ton. However if spinners are prepared to pay US$400 or more then little or no sisal goes into pulp.

Figure 11: Markets for sisal floorcoverings

Figure 12: Minor uses of sisal and other hard fibres

In my view, decorticator flume tow should be a better lower cost candidate for pulping. After drying and a couple of carding passages it should be clean enough to yield much the same amount of pulp per kilo as long fibre.

Abaca is qualitatively superior to sisal or other alternatives, for strong envelopes, but today, the competition in this end use comes from Du Pont's "Tyvek", a melt Blown Polyethylene. Tea bags are another important application for abaca, but in this case food grade Polypropylene is an alternative raw material.

I have forecast a positive future for sisal yarns used as wire rope cores because this is an end use that sisal does very well. It holds the oil that is needed to lubricate and protect steel rope, especially elevator cable that is a premium application. and releases the oil evenly over time.

I have also shown a positive picture for sisal in resin mouldings, buffing cloth and geo-textiles, but the future growth volumes I think will be relatively small, and certainly not large enough to compensate for the ongoing decline in agricultural twines as sisal's largest single end use.

The bulk of the world's geo-textiles are today made from polypropylene. Jute has a foothold in the market for 'greening' products that biodegrade within a year. Coir holds a place for products that should last for 2 to 3 years, and then biodegrade. Sisal's performance lies between these two alternatives; however that seems too narrow a 'niche' to absorb major volumes of fibre.

Sisal works well for the reinforcement of cement in roofing tiles and can replace asbestos which is outlawed in such applications. Cement reinforcement is a vast market. The USA alone uses 450 million cubic yards per year. Steel reinforces less than 1 percent of that volume but plastics, especially PP reinforces over 10 percent. In the USA today cement reinforcement uses about 23 000 tons of Polypropylene, but to me it seems unlikely that sisal can compete either on price or performance.

I am not enthusiastic about bankers but they do have their moments! Here is what Barclay's Bank had to say about sisal in January 1963, and I quote; "Sisal suffers the disadvantage of a high degree of dependence on one main use. Taking sisal and the related henequen together, it is said that up to two-thirds goes into agricultural twines," Almost 40 years later the corresponding figure is 40 percent out of a much reduced sisal volume. Barclay's went on; and this was before any significant quantity of Polypropylene resin was available! "To secure more stability of price, and to maintain prosperity in the face of competition from other fibres, both natural and synthetic, the industry seeks to expand its markets through the development of other uses for sisal." I imagine that at the time Barclays' had lent too much money to African sisal estates. The problem of finding new and commercially viable uses for sisal is clearly not a recent question, nor it is not a matter about which anybody in their right mind would claim to be easily solved, anyway it is now an issue that affects all the so- called "natural fibres". Only a few weeks ago, by my estimate, the world volume of polyester produced and consumed surpassed that of cotton. Cotton is fortunate in that it is a comfortable fibre that has a lot going for it, but from now on whatever it gains in price it will have to be paid for in extra loss of market share.

What new ideas or products are around which could throw sisal growing a much-needed lifeline? At one time, decorticated pulp was thought to be a source of valuable bio-chemicals for use in medicine, the idea was to extract hecogenin from the juice and to use it in the production of cortisone. That prospect fell by the wayside when cheaper man-made chemical equivalents were developed. But there may well be other potentially valuable by-products to be found in the fleshy waste discarded by sisal decorticators, apart from cattle feed and biogas. After all this is an era of rapid advances in biotechnology and medicine, and more research seems to be indicated.

I firmly believe that some lateral thinking is called for, and would like to contribute the following idea for consideration. It is now apparent that the alcoholic drink tequila is enjoying a major success on the US market, and this has created an acute shortage of agave raw material with which to make tequila. Tequila is distilled "pulque" the juice of agave tequilana - a similar plant to sisal except the leaves are broader and the fibre content lower. Yet another variety of agape is distilled to make "mescal". The use of agaves for liquor production is a longstanding tradition in central Mexico; somehow the agro-industrial production of agave fibre developed separately in the Yucatan, and the relevant technical cross-fertilisation never took place.

This is surely an appropriate moment to rectify such an unusual situation. It should not prove too difficult to bio-engineer one or other variety of the agave family, amaniensis, fourcroydes, or sisalana, so that the plant could be both profitably tapped for liquor as well as harvested for fibre? Such an innovative strategy, I propose, could save the world's agave plantations from shrinking, and give sisal the second chance it deserves.

[8] International Textile Consultant, 228 Ballylesson Road, Ballyaughlis, Drumbo, Lisburn, Co.Antrim, Northern Ireland, UK. Phone: +44 232 826 541; Fax: +44 232 836 590; E-mail: [email protected]

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