Silicon dioxide

Endpoint summary

Description of key information

4.1 Appearance / physical state / colour

Study: APC-Set 2-Key_AEROSIL R974

Method (GLP, reliability): Electron microscopy (yes, 1)

Results: Solid: particulate / powder, white, odourless, inorganic

 

4.2 Melting point / freezing point

Study: MP-Set 2-key_melting point_HDK H15_surface-treated_RL1

Method (GLP, reliability): EU method A.1 (yes, 1)

Results: > 800 K / 526.9°C

 

4.4 Density

Study: Dy-Set 2_key_Skeleton density, Cab-O-Sil TS 610, high end

Method (GLP, reliability): OECD 109 (yes, 1)

Results: Skeleton density – 2.16 g/l

 

Study: Dy-Set 2_key_Skeleton density, Cab-O-Sil TS 720, low end

Method (GLP, reliability): OECD 109 (yes, 1)

Results: Skeleton density - 1.85 g/l

 

4.5 Particle size distribution

Low end D50 value is 4.20 µm for HDK H 2000, a pyrogenic nanoform of SAS

High end D50 value is 29 µm for AEROSIL R 976, also a pyrogenic nanoform of SAS.

Similar to the BET, density also these PSD values (which belong here to agglomerates) represent an overall range of the various SAS nanoforms.

 

Study: PSD-Set 2-key_HDK H 2000_low end

Method (GLP, Reliability): ISO 13320 (laser diffraction) (yes, 1)

Results: d50 = 4.20 µm

 

Study: PSD-Set 2-key_AEROSIL R 976_high end

Method (GLP, Reliability): ISO 13320 (laser diffraction) (yes, 1)

Results: d50 = 29 µm

 

4.8 Water solubility

Applying a modified method to accomplish sufficient material wetting, all hydrophobic SAS products analysed (surface treated pyrogenic SAS only) exhibit a solubility between 100 and 130 mg/L in 10 % ethanol/water. It is expected, that other SAS products not tested so far will fit into that range. Thus, we conclude that the solubility of hydrophobic SAS (surface-treated SAS) products does not differ from the results of hydrophilic SAS (non-surface-treated SAS).  

 

Study: key_water solubility OECD 105_AEROSIL R 972_surface treated_RL1

Method (GLP, reliability): EU method A.6 / OECD 105 (yes, 1)

Results: 107 ±0.4 mg/L

 

Study: key_water solubility OECD 105_AEROSIL R 976_surface-treated_RL1

Method (GLP, reliability): EU method A.6 / OECD 105 (yes, 1)

Results: 131.3 ±14.1 mg/L

 

4.12 Auto flammability

The ignition temperature was > 700 °C in the MAIT test performed. No ignition was observed at a maximum temperature of 450 °C in the MIT test.

 

Study: AF-Set 2-key_relative self-ignition_Cabosil TS530_surface treated_RL2

Method(Reliability, GLP): ASTM E1491, ASTM E2019, ASTM E2021 (no, 2)

Results: MIE: >1000 mJ (= no ignition observed); MAIT: 750 °C; MIT: > 450 °C (= no ignition observed)

 

Study: AF-Set 2-key_relative self-ignition_Cabosil TS720_surface treated_RL2

Method(Reliability, GLP): ASTM E1491, ASTM E2019, ASTM E2021 (no, 2)

Results: MIE: >1000 mJ (= no ignition observed); MAIT: 750 °C; MIT: > 450 °C (= no ignition observed)

 

Study: AF-Set 2-key_Dust-Autoignition_HDK N20_surface treated_RL1

Method (Reliability, GLP): VDI 2263 part 1 (no, 1)

Results: The dust/air mixtures of the sample HDK N20 did not ignite in the presence of an ignition energy of 2x 1 kJ as well as 10 kJ (using pyrotechnical igniters.

 

4.13 Flammability

a) Flammability

Study: Fl-Set 2-key_flammability_CAB-O-SIL® TG-820F fumed silica _surface treated_RL1

Method (GLP, Reliability): EU method A.10 (yes, 1)

Results: The sample failed to ignite during the two minutes that the Bunsen flame was applied. The result of the preliminary screening test obviated the need to perform the main test.

 

b) Self-heating

Study: Fl-Set 2-key Self heating_SIPERNAT D 10_low end

Method (Reliability, GLP): UN Test 4 (no, 1)

Results: Using the 10 cm cube at an ambient temperature of 140 °C, the temperature did not exceed a maximum value of 140 °C within 24 hours. Hence the product is not a dangerous good of Div. 4.2.

 

Study: Fl-Set 2-key Self heating_AEROSIL RCX 380_high end

Method (Reliability, GLP): UN Test 4 (no, 1)

Results: Using the 10 cm cube at an ambient temperature of 140 °C, the temperature did not exceed a maximum value of 140 °C within 24 hours. Hence the product is not a dangerous good of Div. 4.2.

 

4.19 Stability, thermal, sunlights, metal

Study: STSM-Set 2-Key thermal

Method (GLP, reliability): thermogravimetric analysis (no, 2)

Results: Surface treated synthetic amorphous silica has melting points >> 300 °C and, therefore, is thermally stable.

 

4.28.8 Nanomaterial dustiness

Synthetic amorphous silica (SAS) is a class of solid, particulate materials, which are composed of nano sized constituent particles. For most SAS materials, the constituent particles are bound in aggregates, which form even larger agglomerates over several length scales. The granulometry refers also to the size of aggregates and agglomerates. The sizes are affected by the environmental conditions, the mixing state and the dispersing forces experienced during processing.

Conventional and standardised dustiness methods do not cover these factors sufficiently, for a complete characterisation of the granulometric state a substitute method represent a multitude of measurement techniques are required to provide more reproducible SAS dustiness equivalent values for the health relevant fractions.

 

Study: Du-Set 2_key_SIPERNAT D 17

Method (GLP, reliability): OECD 110 resp. ISO 13320 (yes, 1)

Results: Considering the dustiness classes according to EN1505133:2013 the dustiness may be evaluated as moderate