Calcined Cristobalite Powder for Silicone Rubber
M4000 calcined cristobalite powder for silicone rubber and selected industrial rubber compounds. The supplied batch report records D50 6.15 μm, SiO2 99.63%, Fe2O3 0.009%, moisture 0.1% and whiteness 94%. Final loading and performance must be qualified in the customer's polymer, filler and cure system.
Specifications
- Mesh Size
- 200mesh,325mesh,M400,M600,M3000,M4000,M6000
- Particle Size
- 3-5mm,1-3mm,1-0.5mm,0.5-0.2mm,0.1-0.2mm,0.1-0mm(120mesh),0.075mm(200mesh)
- SiO₂ Content
- 99.3-99.7%
- Fe₂O₃
- <0.015%
- Specific Gravity
- 2.30 g/cm³
- Whiteness
- 90-98
- Moh's hardness
- 6.5
- Conversion-related parameter
- 80-95%
M4000 • Calcined Cristobalite Mineral Filler
Calcined Cristobalite Powder for Silicone Rubber Compounds
M4000 is a fine calcined cristobalite silica powder produced from selected natural microcrystalline quartz through high-temperature calcination, purification, grinding, classification and magnetic separation. It is intended for compound trials where fine dispersion, low moisture, colour response and mineral-filler consistency are important.
Material Identity and Processing Route
This grade is a calcined cristobalite mineral powder. It is not fused silica, precipitated silica or fumed silica. According to Changtong's product brief, selected quartz is calcined at 1400–1500°C, cooled, sorted and purified before crushing, fine grinding, classification and magnetic separation.
M4000 Batch Test Snapshot
The following results are taken from Changtong's analysis report for sample 260820-1, dated August 20, 2026. The report states that the results apply only to the submitted sample and cites SJ/T 10675-2002.
| Test item | Reported result | Qualification note |
|---|---|---|
| Grade | M4000 | Confirm against current order documents |
| Median particle size, d(0.5) | 6.15 μm | Review the full PSD for formulation work |
| Moisture | 0.1% | Sample-specific result |
| SiO2 | 99.63% | Sample-specific result |
| Fe2O3 | 0.009% | Evaluate against colour limits |
| Al2O3 | 0.21% | Sample-specific result |
| Specific gravity | 2.35 g/cm³ | M4000 report value; not a generic quartz-template value |
| pH | 7.8 | Confirm method when setting acceptance limits |
| Whiteness | 94% | Check cured-compound colour in the customer system |
| Activation value | 95% | Wording retained from the supplied report |
The separate product brief lists an oil-absorption reference of 25.2 g/100 g. Because the supplied M4000 analysis report does not state this item or its test method, confirm it against the current TDS/COA before setting a purchasing limit.
M4000 Particle Size Distribution (PSD)
The supplied laser-particle-size report provides a complete distribution curve for an M4000 average sample tested on November 12, 2024. These PSD results are presented separately from the August 20, 2026 batch analysis above because they were generated on different dates and must not be represented as one batch.
| PSD item | Result | PSD item | Result |
|---|---|---|---|
| D10 | 1.44 μm | Below 5 μm | 35.53% |
| D50 | 7.65 μm | Below 10 μm | 60.96% |
| D90 | 20.54 μm | Below 20 μm | 89.17% |
| D95 | 24.89 μm | Below 30 μm | 98.09% |
| D97 | 27.74 μm | Below 35 μm | 99.45% |
The 2024 PSD report records D50 7.65 μm, while the 2026 sample analysis records d(0.5) 6.15 μm. The difference may reflect sample, batch, preparation or test-condition variation. Use the current lot PSD and COA for contractual acceptance.
Why Evaluate M4000 in Silicone Rubber?
The supplied application brief describes near-equiaxed particles, a fine feel, favourable dispersion and flow behaviour, low oil absorption and useful colour response. In compound development, these characteristics may support practical filler incorporation and surface appearance. Actual mechanical properties and processing behaviour depend on the silicone polymer, reinforcing filler package, loading, mixing sequence, cure system and target hardness.
Calcined cristobalite is a mineral filler and must not be treated as chemically or functionally identical to precipitated or fumed silica. Do not assume a one-for-one replacement ratio. Use controlled side-by-side trials and retain the reinforcing silica required by the compound design.
Suggested Compound Qualification Workflow
Application Fit
| Application | Why trial M4000 | Verify before approval |
|---|---|---|
| Silicone rubber compounds | Fine mineral addition, colour and processing evaluation | Dispersion, cure, tensile, tear, elongation and hardness |
| Rubber rollers and hoses | Cost/performance and surface-quality trials | Flexing, abrasion, ageing and compound viscosity |
| Wire and cable jackets | Mineral-filler consistency and colour response | Electrical, mechanical, flame and regulatory requirements |
Frequently Asked Questions
Is M4000 fused silica?
No. M4000 is presented here as calcined cristobalite powder produced from selected natural quartz. It must not be specified or marketed as fused silica.
Can it completely replace precipitated or fumed silica?
No universal replacement ratio should be assumed. Cristobalite and reinforcing silicas have different structures and functions. Determine the workable balance through controlled compound trials.
Which data should be confirmed for an order?
Confirm grade, full particle-size distribution, chemistry, moisture, whiteness, pH, packing and the current batch COA. Add application-specific acceptance limits where required.
Can Changtong support a qualification trial?
Yes. Share the silicone or rubber type, baseline filler package, target loading, colour, cure process and required mechanical properties so the technical team can discuss an appropriate sample and document set.
Request an M4000 Sample or Quote
Send your polymer type, current filler system, target loading, particle-size requirement, annual quantity and destination. Batch documents and trial requirements can then be matched to your application.
Request a QuoteRelated materials: review high-whiteness cristobalite powder for other engineered-compound applications, or contact Changtong for grade-selection support.
