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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Substance Fatty acids, C18-24, zinc salts is a salt of fatty acids with the inorganic cation zinc. It is a white, solid, powdery inorganic salt with a melting point of 119°C. As the substance started decomposing at approximately 320°C before boiling, no boiling point could be determined. The relative density of substance Fatty acids, C18-24, zinc salts is 1.11. As the substance is a salt with a melting point of 119°C, the vapour pressure can be safely assumed to be negligible, i. e. below the level of relevance (10-5 Pa). The surface tension of substance Fatty acids, C18-24, zinc salts is not considered to be relevant, which is confirmed by the measured surface tension of a 90 % saturated aqueous solution of the structurally related substance Fatty acids, C16-18, zinc salts, which was determined to be 64.56 mN/m (standard deviation 0.05 mN/m). Due to the fact that the surface tension is > 60 mN/m, substance Fatty acids, C16-18, zinc salts is classified as not surface-active substance. Water solubility of substance Fatty acids, C18-24, zinc salts was determined according to regulation (EC) No. 440/2008, A.6, ‘flask method’, results of the three measurements are: 1) 1) pH: 7.00, Zn: 0.06 mg/L; 2) pH: 7.26, Zn: < 0.05 mg/L(LOQ); 3) pH: 7.66, Zn: < 0.05 mg/L(LOQ). Thus, the solubility of the tested substance was < 1 mg/L based on the mean value of measured zinc concentrations of 0.06 respectively < 0.05 mg/L and a zinc amount of the test sample of 9.49%. The highest value of the three measurements was 0.63 mg/L (0.06 mg Zn/L). This value is taken as conservative key value. The partition coefficient of this substance is not considered to be relevant. Substance Fatty acids, C18-24, zinc salts is non flammable.

Pyrophoric properties, flammability in contact with water, flash point, explosive properties, self-ignition temperature, oxidising properties, stability in organic solvents and identity of relevant degradation products as well as dissociation constant and viscosity are not relevant for this substance in accordance with column 2 of the respective sections of Regulation (EC) No 1907/2006, Annexes VII to IX.

The granulometry of a representative test material is summarized as follows:

D50 = 2µm

D90 = 17µm 


Justification for classification or non classification

According to the criteria of REGULATION (EC) No 1272/2008, substance Fatty acids, C18-24, zinc salts does not have to be classified and has no obligatory labelling requirement for physico-chemical properties. Substance Fatty acids, C18-24, zinc salts is not flammable, explosive properties are considered non-relevant for substance Fatty acids, C18-24, zinc salts based on lack of functional groups and oxidizing properties are considered non-relevant based on the chemical structure of the substance. In the long experience with substance Fatty acids, C18-24, zinc salts, no indications on metal corrosivity became evident.

This conclusion is in line with the conclusion of an EU risk assessment carried out on the structural analogue substance Fatty acids, C16-18, zinc salts (i.e. zinc stearate) within the framework of EU Existing Chemicals Regulation 793/93 (EU RAR Zinc stearate (CAS# 91051-01-3, CAS# 557-05-1) Part I - Environment (Final report R074_0805_env, May 2008):

“Data on boiling point, vapour pressure, and surface tension were not provided. In view of the nature of the substance determination of these parameters is considered to be irrelevant. Information on flammability, explosive properties and oxidizing properties is not available. However, on theoretical considerations the compound is concluded to be not flammable, not explosive and not oxidizing."