3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 February 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

ISO 13320 (Particle size analysis - Laser diffraction methods)

Version / remarks:

1999

Deviations:

no

Principles of method if other than guideline:

According to REACH Regulation (EC) No 1907/2006 Article 13(3) tests on substances shall be conducted in accordance with the test methods laid down in a Commission Regulation or in accordance with other international test methods recognised by the Commission or the Agency as being appropriate. No particle size distribution test method is laid down in the relevant Regulation (EC) No 440/2008. The international OECD 110 test guideline ‘Particle Size Distribution/FibreLength and Diameter Distributions’ dates from 1981 and describes two methods in detail; both methods have restrictions and are not applicable to the entire size range. ECHA’s document ‘Guidance on information requirements and Chemical SafetyAssessment-Chapter R.7a: Endpoint specific guidance’ stipulates that many methods are available for particle size measurements but none of them is applicable to the entire size range. ECHA’s guidance mentions the Laser scattering/diffraction as a method suitable for particles of all kind and makes reference to ISO 13320.

GLP compliance:

yes (incl. QA statement)

Type of method:

Laser scattering/diffraction

Type of particle tested:

primary particle

Type of distribution:

volumetric distribution

Specific details on test material used for the study:

Relative density at 20°C: 1.07
Observation of test material in studyreport: white powder with some lumps & clusters

Mass median aerodynamic diameter:

104.512 µm

Remarks on result:

other: MMAD value is the mean of 5 measurements. St.dev.: 7.5 µm (calculated by reviewer)

Key result

Percentile:

D10

Mean:

12.522 µm

St. dev.:

0.67

Remarks on result:

other: Std. dev in µm calculated by reviewer

Key result

Percentile:

D50

Mean:

101.036 µm

St. dev.:

7.2

Remarks on result:

other: Std. dev in µm calculated by reviewer

Key result

Percentile:

D90

Mean:

498.852 µm

St. dev.:

42

Remarks on result:

other: Std. dev in µm calculated by reviewer

Key result

Percentile:

other: D8.4

Mean:

< 10 µm

Remarks on result:

other: St. dev. was not given in the report. The St. dev. could not be calculated by reviewer as there were no individual values given in the study report.

Some heavy agglomerates were still present in the formal analysis.

Conclusions:

Particle size distribution of MDI/ODA: D10= 12.5 µm, D50= 101.0 µm and D90= 498.9 µm. 8.4% is smaller than 10 µm. The MMAD was determined to be 104.5 µm.

Executive summary:

The substance MDI/ODA was visually observed to be a white powder with some lumps & clusters. Under a microscope, the substance was observed to be made up of single crystalline particles, though some agglomerations were observed. The particle size distribution of MDI/ODA was determined using laser diffraction analysis (small volume (wet) module) in a GLP study according to ISO 13320:1999. Each result is the average of five runs.

Particle size distribution of MDI/ODA: D10= 12.5 µm; D50= 101.0 µm; D90= 498.9 µm. 8.4% is smaller than 10 µm. The MMAD was determined to be 104.5 µm.

Description of key information

Particle size distribution: D10= 12.5 µm; D50= 101.0 µm; D90= 498.9 µm. 8.4% is smaller than 10 µm. MMAD= 104.5 µm (ISO 13320: laser diffraction analysis).