Substitution of boric acid by lactic acid as biocide in cooling lubricants

Number

253-EN

Section

General Section

Use

Sector

Manufacture of computer, electronic and optical products, electrical equipment
General manufacturing, e.g. machinery, equipment, vehicles, other transport equipment
Other

Function

Biocide
Lubricating agent

Process

Other

Product category

Biocidal products

Application

Kühlschmierstoffe

Abstract

Boric acid is classified toxic for reproduction EU 1B and endocrine disruptor. It can be substituted by lactic acid with good results in keeping bacteria and fungi under control in water mixable cooling lubricants.

Substituted substances

Boric acid

CAS No. 10043-35-3 EC No. 233-139-2 Index No. 005-007-00-2

Chemical group

Boron compounds; inorganic acids

Classification: hazard statements

H360FD May damage fertility. May damage the unborn child

Other adverse effects

The substance is: endocrine disruptor cat. 1 (EU EDC database), as listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC).

Alternative Substances

Lactic acid

CAS No. 50-21-5 EC No. 200-018-0 Index No.

Chemical group

Carboxylic acids

Reliability of information

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

Reason substitution

ED
CMR

Hazard Assessment

Substance to be substituted: Boric acid is a Substance of very high concern and is included on the REACH candidate list for authorization, according to Article 59 of Regulation (EG) No. 1907/2006. (REACH Regulation). Alternative substance: Lactic acid is not listed in the SUBSPORTplus Database and has no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation).

Description of Substitution

Boric acid has been used for its bactericidal properties in many products while believed to be safe. After it was included on several lists of hazardous substances, including the ECHA candidate list of substances of very high concern, safer alternatives were looked for. Lactic acid can substitute boric acid to prevent the development of bacteria and fungi in cooling lubricants. It can be used for water mixable lubricants based on mineral or ester oil. It works well for machining steel, casting and aluminium alloys. It provides good stability to cooling emulsions by helping to prevent microbial degradation. According to the producer the lactic acid has the following advantages: -it gives comparable or even better biocidal results than boric acid, -it does not generate crystals like the boric acid under certain conditions; - it does not generate residues difficult to re-emulsify; - it does not generate unpleasant odour - at recommended concentrations it is not corrosive - it shows good rinsing and cleaning properties. The disadvantage, according to the producer, is that it precipitates at higher level of water hardness.

Case/substitution evaluation

The substitution is easy to implement. Proliferation of microorganisms in cooling fluids has been regarded in the past as mainly a technological problem. However, exposure to biological agents and to the toxic substances they may generate (mycotoxins) is important to workers health because they may cause diseases and allergies. The biocidal products are therefore needed, but their hazards also need to be taken into consideration. The lactic acid is not classified as hazardous and after its use in various sectors, including consumer goods like cosmetics, it is generally considered safe.

State of implementation

In use

Availability of Alternative

Alternative is available on the market.

Producer/Provider

Curtis">https://www.curtis-systems.de/en">Curtis systems GmbH, Hochheim

Type of information supplier

Producer / distributor

Contact

The description  is based on the presentation Alternative to boric acid. New bacteriostatics for cooling lubricants by Joachim Weimer,  from Curtis systems GmbH, Hochheim, and was published by Curtis systems on their website (https://www.curtis-systems.de/de) in 2007.

Further information

Lactic acidhttp://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=DE&language=EN-generic&productNumber=69775&brand=FLUKA&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Finterface%3DAll%26term%3Dlactic%2Bacid%26lang%3Dde%26region%3DDE%26focus%3Dproduct%26N%3D0%2B220003048%2B219853101%2B219853286%26mode%3Dmatch%2520partialmax"">http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=DE&language=EN-generic&productNumber=69775&brand=FLUKA&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Finterface%3DAll%26term%3Dlactic%2Bacid%26lang%3Dde%26region%3DDE%26focus%3Dproduct%26N%3D0%2B220003048%2B219853101%2B219853286%26mode%3Dmatch%2520partialmax">http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=DE&language=EN-generic&productNumber=69775&brand=FLUKA&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Finterface%3DAll%26term%3Dlactic%2Bacid%26lang%3Dde%26region%3DDE%26focus%3Dproduct%26N%3D0%2B220003048%2B219853101%2B219853286%26mode%3Dmatch%2520partialmax" target="_blank" rel="noopener"> MSDS from Sigma Aldrich Curtis">https://www.curtis-systems.de/en">Curtis systems GmbH: cooling">https://www.curtis-systems.de/en/cooling-lubricants">cooling lubricants MSDS">https://www.curtis-systems.de/en/produktliste-datenblatt">MSDS

Type of publication and availability

Producer presentation on website

Date, reviewed

November 26, 2021