Substitution of alkylphenol ethoxylates (APEO)Summary and conclusionsDescription of raw materials containing APEOIdentification of alternatives to APEO Technical testing of alternatives Health and environmental assessment of alternatives Conclusions The project “Substitution of alkylphenol ethoxylates (APEO)” includes the following phases:
Substitution of APEO and raw materials containing APEO has been tested at Beck & Jørgensen. Description of raw materials containing APEOAlkylphenol ethoxylate is the name of a group of surfactants that can improve the miscibility of different substances with water. The alkyl often contains 8-16 C (carbon), and the ethoxylation varies between 1 and 30, but is normally around 12-13 (EO). APEO is added to paint products as pure substance or as a part of other raw materials. The raw materials containing APEO can be grouped in the following categories:
APEO belongs to the group of nonionic surfactants and can be present in mixtures of particulate substances dispersed/emulsified in water. Binders containing APEO represented 75-80% of the consumption of APEO at Beck & Jørgensen. These binders were based on alkyde, acryl/acrylates and vinylacetate-acrylate emulsions and dispersions. The strategy for substitution of APEO and raw materials containing APEO was to start with the binder, as this process is normally the most comprehensive. Identification of alternatives to APEOWith reference to the identified raw materials containing APEO contacts were established to the producers in order to find out if they were able to supply the same raw materials without APEO. The manufacturers have often developed APEO-free raw materials and these raw materials would be possible substitutes in the actual products without or with few adjustments in the product formulation. Technical testing of alternativesThe technical testing of alternatives (APEO-free) raw materials or alternative surfactants is carried out at the Beck & Jørgensen laboratory or at the laboratory at EnPro. The selection of new binder systems is dependent on the technical properties that can be achieved in the actual formulation. In the present project the aim is to replace four types of binders. In all four cases the options were reduced to two after the testing. It is essential to point out that substitution of the binder, which is the “backbone” in the product, may require a number of adjustments or even reformulation. The dispersion aids and the binder system must be compatible in order to avoid flocculation. Replacement of the anti foaming agents may also be necessary to get the proper functionality. This means that substitution of other raw materials can be necessary even if they do not contain APEO. As one binder is used throughout one product group it is not always possible to select the technically best alternative, since the consequence might be that a number of new binders/raw materials have to be introduced in the same product group. The project demonstrated that it was (or would be) possible to substitute APEO and raw materials containing APEO. The substitution may be a long process, as many raw materials with different function have to work together. The aim was to remove APEO from the products and retain as much of the original formulation as possible, since development of new formulations is a more comprehensive time and resource consuming process. The experience is that it is often impossible to get complete information about raw materials containing surfactants in advance. Health and environmental assessment of alternativesThe health and environmental assessment was performed as a screening followed by a detailed assessment of groups of substances selected on the basis of the results of the technical testing:
For comparison, the health and environmental aspects of APEO were presented. The results of the health and environmental assessment are presented in chapter 5 Miljø- og sundhedsvurdering. ConclusionsThe result of the survey on alternative surfactants to the APEOs used by Beck & Jørgensen in their products is summarised in Table 1. Table 1 Beck & Jørgensen has during the project substituted a number of raw materials containing APEO with alternatives. The APEO-free raw materials are all based on the three described groups of surfactants, i.e. alkylsulfates, alkylether sulfates og alcohol ethoxylates. These three groups of surfactants are in general easily degradable under aerobic as well as anaerobic conditions and the surfactants are toxic or very toxic to aquatic organisms. Alkyl sulfates and alkylether sulfates are not considered to be bioaccumulating whereas a few alcohol ethoxylates (long-chained with few ethoxylate units) have a potential for bioaccumulation. The alkylphenol ethoxylates, which the above surfactants have replaced, have on the other hand the problem that their degradation products (for instance nonylphenol) are very toxic to aquatic organisms, are not easily degradable and have at the same time a tendency to bioaccumulation. Even if the alternative surfactants in general are toxic or very toxic to aquatic organisms too, they are on the other hand also quickly degradable in the environment and for that reason there is an environmental advantage in substituting the APEOs, which are hazardous to the environment, with these alternative surfactants. With regard to health, there is furthermore the advantage of the substitution that the degradation product nonylphenol is avoided. For this product, evidence for hormone disturbing effects is found.
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