Abstract/Summary

This study reviews the market opportunities for use of esters of rapeseed oils as solvents. Potential market uses and requirements are reported, along with a discussion of the technical properties required of vegetable-based solvents for comparison with conventional organic solvents. This report examines the opportunities as well as the constraints and barriers affecting uptake and further development of bio-solvents. There is increasing legislative pressure encouraging change and these driving forces such as legislation to reduce use of volatile organic compounds (VOC’s) and measures to control the use of hazardous substances in the workplace are reviewed and discussed. Estimates of market costs, and, where available, costs of commercially available products are used for comparison with conventional organic solvents. Vegetable oil derived fatty acid esters have a number of characteristics which suit their use in the solvent sector. Rape methyl ester has a high solvating capacity, due to its small ester group, but conversely, its long carbon chain length (predominantly C18) leads to relatively high viscosity and its high levels of unsaturation restricts the natural life of the oil through oxidative degradation. The latter is only of concern where long term recycling and re-use are considerations (i.e. in cleaning dip baths). In the solvent market, there appears to be limited opportunity for use of rape fatty acid esters in the surface coating sector, which is increasingly converting to use of water-based formulations. Other vegetable oils predominate in this sector because of technical advantages in terms of drying time or ability to cost effectively produce alkyl resins. The second most important industrial user of solvents in the UK is the printing industry, both in ink formulations and in wash down solutions. Progress has been made in developing ink formulations and significant volumes are produced and used in the UK and Northern Europe, but use in the UK probably accounts for no more than 20% of the market. Vegetable oils have been used for some time in the ink sector with no reported problems and few technical obstacles or barriers exist to further adoption. Rape methyl ester is commonly used in ink formulations. Significant market penetration has been achieved in some sectors, but is limited by significant drivers to change. There is a significant opportunity for use of rape methyl ester in print cleaning solvents. There are a number of misconceptions in the industry currently preventing greater uptake. Benefits in terms of the working environment for print operators and reduced use of solvent come at a cost, in terms of high initial price and increased labour in the cleaning process. Fears over problems with swelling of rubber components appear to be unfounded with current formulations, and there appears to be no greater fire risk with rape than coconut based fatty acid ester products. Further education and demonstration is required to try and overcome some of the current misconceptions and to prove the technology to the industry. There is also a need to prove the worth of vegetable esters against the recently introduced hydrocarbon based high boiling point solvents. The printing industry has adopted these latter materials to comply with increasing legislative and health and safety pressures, as they generally involve little change to current working practice. However, to 2 date there have been few conclusive studies to quantify the cost benefits against vegetable oil based technologies. The view of the health and safety industry is that vegetable based esters are safer to the working environment than high boiling point solvents, but vegetable- based solvents will have to prove their worth in this respect to encourage further uptake. Of the remaining industrial sectors, there are opportunities for use of rape methyl ester products in the metal cleaning sector, but much of the industry relies on recycling and re-use of solvent materials which results in a preference for coconut based products with greater oxidative stability. The key opportunities for rape derived fatty acid esters as metal cleaners are in one-off cleaning operations, tar and bitumen removal and in polishing operations for vehicles, however the demand in this sector is likely to be limited. Other niche areas of interest include development of treatments for oil spill clean up, and formulations for removal of graffiti. Rape methyl ester has significant technical potential in both these areas, but the demand in the former case is likely to be sporadic, and further work would be required to ensure no significant environmental damage would result from the use of the solvent itself, current evidence suggests it is more benign than current solvents used for oil clean up. Further work is required to develop suitable, effective formulations of vegetable fatty acid esters and working practices in the UK. There is a need for close working relationships between solvent users, suppliers and machinery manufacturers to ensure there are no problems with use of vegetable esters, which can affect rubber, plastic and epoxy materials. The development of these potential markets is dependent upon certain driving forces (e.g. banning of hazardous products, government or EU policies, health and safety legislation and public opinion). Although, currently they cannot be seen as a total substitute for petrochemical based solvents, predictions suggest there could be at least a 12.5% market share for vegetable oil-based solvents by 2010 in a total market of 4-4.5 million tonnes per annum. The key barriers identified by industry to adoption of vegetable based bio-solvents includes cost of materials, costs of capital investment required to introduce new technology and lack of recognition of the potential damage to workers health which can potentially arise from conventional volatile solvent use. In the metal cleaning sector, solvent use has been shown to be significantly reduced in some cases by adopting vegetable based esters, leading to significant costs savings. There are a number of other cost benefits which need to be taken into consideration including reduced risk to workers health, lower risk of fire and explosion and reduced level of hazardous waste to dispose of. All of these costs benefits need to be balanced in order to help users weigh up the costs of converting to vegetable based solvents. It is estimated that in the most promising sector, development of print washes based on rape methyl ester could lead to an ongoing demand for around 50,000 tonnes of rape oil per annum in the UK if at least half of the print wash solvent use was derived from rape oil. Niche markets in other sectors could add to this demand.