FAIR-CT98-9588 Bio-liquid mixtures for solvent and/or detergent applications

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Bulk Chemicals : Detergents : FAIR Area 1.2 - Green Chemicals and Polymers Chain : Vegetable Oil/Fat

	Contract No:	FAIR-CT98-9588
	Date Prepared:	March 2001
	Source:	Final Report

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Final Report Executive Summary

Introduction

Over the last few years there has been a growing interest in cleaning agents and solvents that are less hazardous for the end-users, producers and environment. This interest arises from health concerns, growing environmental awareness and future financial concerns originating from expected higher levies and taxes of more hazardous compounds (eco-tax etc.). The challenge is to find replacements that have similar performance and costs, and additionally have a reduced impact on the environment and health of workmen concerned. Various alternatives have been proposed and investigated, such as replacements with water-based systems, reduced usage of solvents, reactive diluents, aqueous cleaners with extreme acidity values (pH < 1 or pH > 13), etc. Not all these alternatives are viable for every application and not all these alternatives are really less hazardous. Hence, this project has aimed to find suitable substitutions of organic solvents by bio-liquids and of synthetic surfactants by bio-surfactants in cleaning agent formulations and paint formulations.

Bio-liquids and bio-surfactants are solvents and surfactants originating from agricultural raw materials, which potentially possess a reduced impact on health and environment. In this project the development of four different cleaning agents based on bio-surfactants and bio-solvents have been investigated as well as paints based on bio-solvents.

Objectives

The aim of the project was the development of liquid mixtures of biological origin for the following sectors:

• To replace organic solvents in speciality paint formulations without changing the high performances of the formulations
• To formulate one fast cleaning agent for the offset print industry
• To formulate one water soluble and/or water emulsifiable bio-detergent for floor cleaning purposes
• To explore the possibilities to recycle emulsions based on bio-liquids by breaking and distilling the bio-liquids

Results

Floor cleaning agents A cleaning test was developed based on (coloured) crude palm oil as model dirt. Pure surfactants and surfactant mixtures were tested for their cleaning performance. A formulation with an alkyl sulfonate, an alkyl polyglucoside and an alkyl polyethoxylate showed the best cleaning performance, close to that of the commercial SMB-50. This fully new formulated product has nearly half the COD value as compared to PNRSA's most successful cleaning agent, a substantial lower pH which diminishes possible irritating aspects while it contains a substantial reduction of the total amount of ingredients used. Slight changes into the new formulation will make the new cleaning agent in full compliance with the SWANN or the EU-eco-label.

Paint solvent For one primer and two finishes based on alkyd or an acrylic resin, the Hansen solubility parameters were determined for the binders. The aim was to exclude aromatic solvents and other hazardous hydrocarbon solvents, Hansen Solubility Parameters and the evaporation profile have been calculated for various solvent systems. On the basis of these parameters new solvent systems were formulated that can dissolve the binder and at the same time have the same drying properties as the original paint system. The calculated results showed that it was possible to get very similar drying properties using lactates instead of the aromatic solvents. The dispense was somewhat more problematic as it was shown that lactates and dispense was not very compatible. The new mixture has a substantial lower POCP value and possesses a substantial lower aquatic toxicity and neurotoxicity. Based on the OAR method, the new product imposes a higher occupational health effect than the original mixture, mainly caused by a proposed low MAC value of ethyl lactate by the Health Council in the Netherlands. The VOC directive cannot be met either by the renewable solvent mix that has been developed

Printing ink cleaning agents For the formulation of a printing ink cleaning agent with use of fatty acid esters instead of de-aromatised hydrocarbons a list of available bioliquids was established based on Hansen Solubility Parameter calculations by ENPRO. The list contains vegetable esters (oleates, laurates, caprates and stearate), dipentene as well as lactate esters. The lactates and dipentene have a higher polarity than most vegetable esters and were excluded from the study. Within the group of vegetable esters, the size of the ester group has the largest influence on solubility behaviour especially the tendency to swell rubber. A vegetable ester with a short main chain can still have a rather low viscosity ant thus have a good miscibility with an ink- cleaning agent system. Still the evaporation is so low that the ester is unable to evaporate. Therefore, an emulsifier is still a necessity at room temperature to be able to remove all residues from the printing rollers.

Micro-emulsion based cleaning agents It is possible to form micro-emulsions of rapeseed oils and ester derivatives with the right choice of surfactants to be used as printing ink cleaning agent. A specific water - rapeseed oil - alkyl polyethoxylate formulation at low surfactant concentration has been developed as the optimal system. For another type of rapeseed oil an alkylpolyglucoside was found to be the best surfactant, These combinations are not good enough to form a single-phase micro-emulsion, but a middle- phase micro-emulsion is possible. The micro-emulsion of a rapeseed oil with an alkyl polyethoxylate has the best stability and also a good performance in the drip tests. All formulations were developed and prepared by ATO and subsequently recommended to AARHIJS.

Recycling of emulsion based cleaners Pure rapeseed ester and coconut ester were successfully vacuum-distilled at 1 mbar by ATO. The recoveries are high (91-94 %) and the composition changes are only marginal. Only the higher boiling components in the esters were not fully recovered. Both rapeseed esters and coconut esters can also be recovered from emulsion cleaning agents (water, ester and alkylpolyglucoside) polluted with green ink, by breaking and vacuum distillation. The distillate is polluted with some off-flavours originating from the ink. A second distillation decreased the amount of off-flavours to acceptable levels. A higher condenser temperature will probably improve the ester quality. The recoveries of both esters are good (94%), but part of the high boiling components are left behind in the 5% residue. They are less well recoverable compared to the pure esters because of the increase of the pollution concentration in the residue.

These results were disseminated to ATFREC.