Number

049-EN

Section

General Section

Use

Abstract

This document describes how a large portion of the halocarbons used and manufactured in Sweden were phased out during the late 1980´s and early 1990´s. Several specific examples are mentioned concerning what chemicals were substituted and what the alternatives were. The chemicals discussed are mainly: dichloromethane, trichloroethylene, 1,1,2-Dichloro-1,2,2-trifluoroethane and 1,1,1-trichloroethane.

Substituted substances

Alternative Substances

Reliability of information

Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication

Reason substitution

CMR
physical hazards

Other type of alternative

Some of the alternatives proposed in this study are non-chemical. Among the more general solutions are the reduction of unnecessary cleaning and degreasing and sometimes even a total change in production or manufacturing procedures. Other, more specific solutions included cleaning processes using inert gas and the utilization of high performance mixture heads. In paint stripping, general chemical alternatives have been proposed, these include acidic-, or alkaline stripping, pyrolysis and fluidized bed stripping.

Hazard Assessment

Substance to be substituted: Several of the hydrocarbons mentioned in the report are associated with adverse health effects. Trichloroethylene is included on the REACH authorisation list, according to Article 62 of Regulation (EG) No. 1907/2006(REACH Regulation). 1,1,1-Trichloroethane is harmful if inhaled and harms public health and the environment by destroying ozone in the upper atmosphere. Dichloromethane is included on the REACH restriction list, according to Article 73 of Regulation (EG) No. 1907/2006(REACH Regulation). Alternative substances: The alternatives are classified with less hazard statements but should none the less be handled with care, because of their physical properties. Water, terpene, nitrogen, sodium carbonate and 1,2,3-Trimethylbenzene are not included in the database of hazardous substances according to SUBSPORTplus screening criteria (SDSC) and have no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation). Sodium hydroxide is not listed in the SUBSPORTplus Database.

Description of Substitution

The following examples of substitution have been proposed by the Swedish Environmental Protection Agency (SNV) and the Swedish National Chemicals Inspectorate (KEMI). The resulting substitutions have all been discussed with representatives from the affected industry and for each substitution consequences and possibilities have been analysed. Substitution of trichloroethylene with aqueous cleaning and other solvents e.g. alcohol when degreasing metals. This substitution was carried through in several ways. First of all, the solvents themselves were substituted, the use of trichloroethylene stopped and instead different solvents were used, especially those based on alcohol. Another way trichloroethylene was phased out was by changing the grease, allowing degreasing by with other solvents. A reduction of unnecessary degreasing was also implemented. The second example of substitution of halocarbons concerns the cleaning of electronics and the manufacturing of circuit boards. 1,1,2-Dichloro-1,2,2-trifluoroethane (CFC113) was in the 1980´s used to clean electronics. This use of CFC113 was phased-out by a variety of methods including a complete remake of the manufacturing process to eliminate the need for cleaning. It was also found that cleaning by processes based on inert gas and use of terpenes in cleaning were suitable alternatives. In the manufacturing of printed circuit boards, dichloromethane and 1,1,1-trichloroethane were the compounds most widely used in the 1980´s. These compounds have since then been substituted with an alkaline-soluble film, which is developed and stripped in aqueous solutions at successively elevated pH-intervals using sodium carbonate or sodium hydroxide. The third example concerns dichloromethane and its use as a cleaning agent in the plastic industry. It is especially used for removing reactive polymer components from mixing equipment such as mixing heads. The phase-out of dichloromethane in this use has been accomplished by switching to non-halogenated solvents such as trimethylbenzene. Another solution has been the utilisation of high-performance mixing heads where the mixing takes place in the mould instead of inside the mixing head which makes cleaning of the mixing head unnecessary. Dichloromethane is also used in industrial paint stripping where the detail to be stripped are traditionally dipped in a mixture of dichloromethane and an organic acid, e.g. formic acid. An alternative to this approach is to immerse the parts in liquid nitrogen followed by shaking or blasting. Acidic or alkaline stripping as well as pyrolysis and fluidised bed stripping are other technical alternatives to dichloromethane. The report also addresses several other areas where halocarbons have been phased out by chemical substitutions, changes in the manufacturing process or technical solutions.

Case/substitution evaluation

This is an extensive document covering many substitutions of halocarbons. Many of the alternatives mentioned are better than the original substances from a hazard point of view. This substitution needs to be improved as the alternatives contain still risks for human health. Especially Ethanol is listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC). Therefore, the alternatives should be handled with care and a better solution should be sought. Nevertheless, this case study remains as an example, as the overall risk is significantly reduced.

State of implementation

Partial capacity

Date and place of implementation

Sweden

Availability of Alternative

Market adjusted and substitutes are available.

Type of information supplier

Producer / distributor
Research

Contact

Tomas Rydberg, Chemical Environmental Science, Chalmers University of Technology.

Type of publication and availability

Scientific publication

Date, reviewed

December 11, 2020