REACH – Applications for authorisation AFA006-01 – TCE

Overview

Public consultation on alternatives

Reference: AFA006-01

Applicant: ENTEK International Limited

Application type: Review Report

Substance name: Trichloroethylene (TCE)

EC Number: 201-167-4

CAS Number: 79-01-6

Proposed use: Use of trichloroethylene as an extraction solvent for removal of process oil and formation of the porous structure in polyethylene-based separators used in lead-acid batteries

Broad information on use applied for (conditions of use and function):

Lead acid battery separators are primarily composed of ultrahigh molecular weight polyethylene (UHMWPE), precipitated silica and oil. UHMWPE is a unique polymer that requires a large percentage of process oil to be extruded in sheet form. This polymer imparts the necessary mechanical properties for handling in the manufacturing process. It also imparts high puncture strength in the finished product as demanded by customers.

Trichloroethylene is used for the effective extraction of oil from polyethylene separator sheet in enclosed solvent baths. This allows efficient use of energy and control and capture of solvent vapour. There is significantly less oil in the finished product than the amount of oil required for manufacturing separators; therefore, a solvent is required to remove the majority of the oil from the extruded sheet. After removal of the required amount of oil, the solvent must then be evaporated from the sheet. This step leaves behind the required amount of porosity to enable ion transport in a battery.

Trichloroethylene is recovered in both vapour and liquid form at different points in the manufacturing process. Liquid Trichloroethylene is recovered via distillation of the oil/Trichloroethylene mixture and from phase separation of the water/Trichloroethylene mixture condensed during the steam drying stage. Finally, Trichloroethylene vapour is recovered through adsorption/desorption in carbon beds. The recovered Trichloroethylene is then reused in the ENTEK continuous separator manufacturing process.

Trichloroethylene is stable and nonreactive with the grade of stainless steel used throughout the ENTEK plant for equipment that handles solvent (e.g., piping, valves, fittings, carbon beds, extractor, and dryer).

The solvent must be highly miscible with the process oil and non-flammable in the ENTEK continuous separator manufacturing process. After removal of the majority of process oil, the oil/solvent mixture must be distilled into its separate components for reuse in the manufacturing process.

Trichloroethylene enables key separator characteristics by:

• Controlled quantitative removal of process oil from the extruded UHMWPE separator sheet
• Evaporation of solvent from the separator sheet to leave behind the required pore size distribution and percent porosity
• Having negligible impact on battery performance even if trace amounts of residual solvent remain in the finished product
• Closed loop recycling which allows for safe reuse of the solvent in the manufacturing process and delivery of the separator to the customer at a competitive price

List of descriptors:

• Sector of end use (SU): 12
• Environmental release category (ERC): 4
• Process category (PROC): 2, 8b and 13
• Product category (PC): N/A
• Article category related to subsequent service life (AC): N/A
• Technical Function: Solvent

Annual tonnage used: 

• 10-100 tonnes

Review period requested: 12 years

How to submit comments

Provide some basic information on possible alternative(s) in the online survey below but more detailed information should be provided in document(s) prepared using the commenting templates in the related section below. A “public version” should always be completed and will be published after the consultation has closed. If you want to include confidential information in your submission, please additionally complete a “confidential version” and submit both versions as attachments.

The consultation lasts for 8 weeks (unless otherwise specified) and closes at 23:59 London time (BST).