High Purity Quartz Functional Reinforcing Filler: Technical Considerations and Application Analysis of SF210 and RS925

In the field of polymer composites, the performance boundaries of fillers are being continuously expanded. Traditional single-function fillers—reinforcing, thermally conductive, wearresistant, insulating, or colorant—typically satisfy requirements in only one dimension, struggling to address multidimensional performance demands. GreenThinking® SF210 and RS925, as two representative products of highpurity quartzbased functional reinforcing materials, share the technical genes of high chemical purity, high whiteness, and chemical inertness, while establishing clear functional differentiation: SF210 focuses on thermal conductivity and insulation (thermal conductivity 12.5 W/K·m, dielectric loss 0.0018), and RS925 focuses on wear resistance and lightcolor compatibility (D50 2.22.8 μm, whiteness ≥92%). Based on TDS standard test data, this paper systematically evaluates the synergistic application potential of these two products in rubber, plastics, adhesives, coatings, and electronic encapsulation from five dimensions: technological homology, differentiated functional mechanisms, empirical performance, process compatibility, and lifecycle value.

1. Industry Status: The Contradiction Between MultiDimensional Demands and SingleFunction Supply

The functional modification of polymer composites is facing an increasingly complex demand matrix: thermal conductivity determines the heat dissipation efficiency and service life of electronic devices; wear resistance directly defines the replacement cycle of dynamic products; insulation is the safety baseline for electrical applications; chemical inertness ensures performance stability in acidic, alkaline, and hightemperature environments; whiteness determines the feasibility of lightcolored and colored products.

However, conventional filler systems have long been constrained by the structural contradiction of “single function, multidimensional limitations” :

Filler Type	Advantages	Inherent Limitations
Carbon Black	Excellent reinforcement/wear resistance, controllable cost	Dark black color, unusable in lightcolored products
Precipitated Silica	Can be used in lightcolored products	Difficult dispersion, high Mooney, high processing energy
Alumina	Good thermal conductivity	High hardness, equipment wear, high cost
Boron Nitride	Excellent thermal conductivity	Prohibitive cost, poor economy
Calcium Carbonate/Talc	High whiteness, low cost	Limited reinforcement and wear contribution
Conventional Silica Powder	Good insulation, chemical inertness	Insufficient thermal conductivity and wear resistance

However, conventional filler systems have long been constrained by the structural contradiction of “single function, multidimensional limitations” :

The essence of this contradiction is: achieving thermal conductivity, wear resistance, insulation, high whiteness, chemical inertness, and economy in a single filler is nearly impossible under traditional technical pathways. Both SF210 and RS925, derived from highpurity quartz with distinct particle size designs, surface treatments, and functional orientations, respectively break through the paired contradictions of “thermal conductivityinsulationinertness” and “wear resistancehigh whitenessinertness,” forming a complementary functional material combination. In this context, SF210 and RS925 stand out as a high purity quartz functional reinforcing filler that addresses multiple performance gaps simultaneously.

2. Technological Homology: DualFunction Evolution from the HighPurity Quartz PlatformSF210 and RS925 share the same technology platform—highpurity natural

Common Gene	Technical Connotation	Engineering Value
High Chemical Purity	SiO₂ ≥99.4% (SF210) / highpurity grade (RS925); Fe₂O₃ ≤0.012% and ≤0.125% respectively	No catalytic side reactions, aging resistance, batch consistency
Chemical Inertness	No reaction or degradation under catalysts, multicomponent, hightemperature, or acid/alkaline environments	Suitable for harsh chemical environments, does not interfere with curing/vulcanization systems
High Whiteness	SF210 ≥95%, RS925 ≥92%	Directly usable in lightcolored/colored products, no additional masking required

2. Technological Homology: DualFunction Evolution from the HighPurity Quartz Platform

SF210 and RS925 share the same technology platform—highpurity natural quartz processed through precision manufacturing and surface activation treatment. This technical foundation endows both products with three common genes:

This common platform means: formulation engineers can select “thermal conductivity + insulation” or “wear resistance + light color” functional directions according to needs under the same technical logic, without rebuilding trust in material compatibility. Furthermore, both products can be classified as a high purity quartz based reinforcing material that delivers consistent performance across various polymer matrices.

3. Differentiated Functional Mechanisms: Clear Division of Labor, Synergistic Complementarity

3.1 SF210: Thermal ConductivityInsulation DualFunction Positioning

SF210’s differentiated performance derives from three technical anchors:

• Particle Size Design: D50=1.72 μm, D100=7.43 μm — submicron concentrated distribution, facilitating thermal conductive network formation.
• Crystal Structure: Highpurity quartz crystal, Mohs hardness 7 — thermal conductivity 12.5 W/K·m, 410 times that of conventional silica powder.

Performance Indicator	Typical Value	Engineering Significance
Thermal Conductivity	12.5 W/K·m	Efficient heat dissipation, reduced device operating temperature
Dielectric Constant (Dk)	4.66	Controllable signal transmission loss
Dielectric Loss (Df)	0.0018	Extremely low energy loss at high frequencies
Mohs Hardness	7	Wear resistance and rigidity contribution

• Surface Activation: Improved interfacial bonding with polymer matrix, reduced interfacial thermal resistance, while maintaining insulation (dielectric constant 4.66, dielectric loss 0.0018).

By virtue of these characteristics, SF210 acts as an excellent thermally conductive insulating filler for polymers, and also serves as a thermally conductive and electrically insulating filler in demanding electronic applications. Its low dielectric loss of 0.0018 makes it an ideal thermally conductive insulating filler with dielectric loss 0.0018 for high frequency electronic applications, ensuring signal integrity in highfrequency circuits. Additionally, SF210 is a high purity quartz based thermally conductive filler with electrical insulation for electronic potting compounds, providing reliable thermal management and electrical safety for potting and encapsulation systems. When used in silicone rubber systems, it performs as a High thermally conductive reinforcing filler for silicone rubber, enhancing both thermal dissipation and mechanical strength.

3.2 RS925: Wear ResistanceHigh Whiteness DualFunction Positioning

RS925’s differentiated performance derives from two core indicators:

• Submicron Particle Size: D50=2.22.8 μm, D97≤7 μm — approaching the scale of carbon black aggregates, reinforcement approaching N550.
• High Whiteness: ≥92% — no additional pigmentation or masking needed in lightcolored/colored products.
• Low Impurities: Fe₂O₃≤0.125%, loss on ignition≤0.3% — reduced catalysis of thermooxidative aging.

Performance Indicator	Typical Value	Engineering Significance
Median Particle Size D50	2.22.8 μm	Good reinforcement, approaching carbon black levels
Maximum Particle Size D97	≤7 μm	No oversized particles, smooth product surfaces
Whiteness	≥92%	Direct application in lightcolored/colored products
Mohs Hardness	7	Significant wear resistance contribution

RS925 is specifically engineered as a surface activated submicron silica powder for high wear resistance in light colored rubber products, where its fine particle size and surface modification ensure excellent dispersion and abrasion resistance. It also functions as a high whiteness wear resistant quartz filler for replacing carbon black in colored rubber compounds, enabling brightly colored rubber articles without sacrificing durability. For tire applications, RS925 is an ideal wear resistant high whiteness mineral filler for light colored tire sidewall compounds, offering both aesthetic and performance benefits. Moreover, with its low impurity profile, it qualifies as a high purity quartz reinforcing filler with low impurity content for improved polymer weathering resistance, extending the service life of outdoor rubber components. As a high purity quartz powder with Mohs hardness 7 for improving polymer composite wear resistance, RS925 provides a hard, durable phase that significantly enhances abrasion resistance in dynamic applications.

3.3 Functional Comparison and Synergistic Scenarios

Functional Dimension	SF210	RS925	Synergistic Value
Thermal Conductivity	★★★★ (12.5 W/K·m)	★★	SF210 leads thermal scenarios
Wear Resistance	★★★ (Mohs 7)	★★★★ (Fine size + high hardness)	RS925 leads wear scenarios
Insulation	★★★★ (Df 0.0018)	★★★ (Highpurity quartz commonality)	Both usable in insulation scenarios
Whiteness	★★★★★ (≥95%)	★★★★ (≥92%)	Both usable in lightcolored products
Chemical Inertness	★★★★★	★★★★★	Shared technical gene

Example Synergistic Application Scenarios:

• Electronic Potting Compounds: SF210 leads thermal conductivity + insulation, RS925 synergistically enhances wear resistance and scratch resistance. Together they provide a comprehensive solution as a high purity quartz based thermally conductive filler with electrical insulation for electronic potting compounds while also contributing to wear protection.
• HighPerformance LightColored Coatings: RS925 leads wear resistance + whiteness, SF210 synergistically enhances thermal conductivity (heatdissipating coatings). In such systems, RS925 works as a submicron quartz based functional filler for high performance adhesives and protective coatings, delivering both decorative appearance and durability.
• WearResistant Thermally Conductive Rubber Products: Combined use achieves the triple goal of “wear resistance + thermal conductivity + insulation,” where SF210 provides the thermally conductive and electrically insulating filler function and RS925 contributes high wear resistance.

4. Empirical Performance Boundaries: Standardized Test Data

4.1 SF210 Core Performance Data

Test Item	Test Method	Unit	Typical Value
D50	Laser Particle Size Analyzer MS2000	μm	1.72
D100	Laser Particle Size Analyzer MS2000	μm	7.43
Moisture Content	Weight Method	%	0.12
Whiteness	Whiteness Meter	/	95
SiO₂ Content	Weight Method	%	99.4
Fe₂O₃ Content	Spectrophotometer	%	0.012
Density	—	kg/m³	2.64×10³
Mohs Hardness	—	/	7
Thermal Conductivity	—	W/K·m	12.5

4.2 RS925 Core Performance Data

Test Item	Unit	Typical Value
D50	μm	2.22.8
D97	μm	≤7
Whiteness	/	≥92%
Moisture	%	≤0.15%
Loss on Ignition	%	≤0.3%
Fe₂O₃	%	≤0.125%
Al₂O₃	%	≤0.5%

4.3 Critical Examination of Standardized Testing

The above data are obtained through standard methods and constitute a necessary basis for material selection. However, the following boundaries should be noted:

1. SF210’s “matrix dependence” for thermal conductivity: 12.5 W/K·m is the filler’s intrinsic value. The composite’s final thermal conductivity depends on the filler’s volume fraction, dispersion state, and interfacial thermal resistance. Surface activation treatment can reduce interfacial thermal resistance, but actual values require verification through specific formulations.
2. RS925’s “dispersion sensitivity” for wear resistance: Wear performance is highly dependent on filler dispersion uniformity. Agglomerates not only fail to contribute to wear resistance but become preferential initiation sites for wear. Shear force control in mixing is critical.
3. Tradeoff in processing equipment wear for both products: Mohs hardness 7 implies greater wear on mixing and extrusion equipment compared to soft fillers, which must be considered in equipment selection and maintenance strategies. The surface activation treatment of SF210 and RS925 can partially reduce the fillermetal friction coefficient.

5. Process Consistency: Transition Control from Formulation to Production

5.1 Common Process Considerations

Despite different functional positioning, the two products face similar critical variables in process transition:

• Dispersion Process Verification: Dispersion effectiveness of submicron fillers depends on initial mixing shear force input and the compatibility of wetting/dispersing agents. Dispersion effectiveness verification (such as SEM crosssection observation and screen pack pressure rise testing) is recommended when transitioning formulations.
• Curing/Vulcanization System Compatibility: Chemical inertness means neither product interferes with peroxide vulcanization, platinumcatalyzed addition, or epoxy curing reactions — providing design freedom for formulation engineers, but also meaning reinforcement is entirely dependent on physical filling and interfacial bonding, not chemical crosslinking participation.
• Loading Boundary Exploration: High loading brings greater functional gains but may increase system viscosity. The optimal balance between “functionality” and “processability” must be identified.

Process Variable	SF210	RS925
Primary Focus	Thermal conductive network construction	Wear dispersion uniformity
Critical Control	Ensuring continuous thermal pathways in matrix	Ensuring no agglomerate residues
Recommended Testing	Thermal conductivity measurement, SEM crosssection	DIN abrasion test, dispersion rating

5.2 Differentiated Process Recommendations

Field audits at multiple enterprises reveal that even with identical formulations, the performance scatter of final products often depends on precise control of initial mixing shear force and dump temperature stability. This observation underscores that indepth engagement during the process validation phase holds greater quality control value than raw material inspection alone.

6. LifeCycle Value Analysis

From a Total Cost of Ownership (TCO) perspective, the value creation logic of the two products can be quantified respectively:

Value Dimension	SF210 Value Anchors	RS925 Value Anchors
Material Cost	Highpurity quartz raw material, superior to boron nitride/alumina	Highpurity quartz raw material, superior to imported lightcolored wear fillers
Processing Cost	Surface activation improves dispersion, reduces energy consumption	Surface activation improves processing fluidity
Quality Cost	High purity ensures batch consistency	Precision classification ensures concentrated particle size distribution
Service Life	Thermal conductivity extends electronic device life	Wear resistance extends dynamic product life
Safety/Compliance	High insulation ensures electrical safety	Low impurities enhance aging resistance

Taking electronic potting compounds as an example (SF210): replacing conventional silica powder can increase thermal conductivity from 12 W/K·m to 35 W/K·m, reducing device operating temperature by 1015 °C and potentially doubling electrolytic capacitor lifespan. Taking lightcolored conveyor belt cover compounds as an example (RS925): replacing conventional precipitated silica can reduce DIN abrasion loss by 1525%, extending cover compound service life by 2030%. As a high purity quartz functional reinforcing filler, both products deliver superior lifecycle value compared to conventional alternatives.

7. Industry Application Map

Application Area	Recommended Product	Core Value
Electronic Potting/Encapsulation	SF210	Thermal conductivity 12.5 W/K·m, dielectric loss 0.0018 — an ideal thermally conductive and electrically insulating quartz powder for high voltage insulation systems
HighWearResistant Rubber Products	RS925	D50 2.22.8 μm, whiteness ≥92%
LightColored/Colored Tire Sidewalls	RS925	Wear resistance + light color, whiteness ≥92% — a proven wear resistant high whiteness mineral filler for light colored tire sidewall compounds
HighPerformance Adhesives/Coatings	SF210 / RS925	Stiffness + thermal conductivity (SF210) / wear resistance + decorative (RS925); RS925 also serves as a submicron quartz based functional filler for high performance adhesives and protective coatings
Engineering Plastic Modification	SF210	Thermal conductivity + dimensional stability
Thermal + Wear DualDemand Scenarios	SF210 + RS925 Combination	Synergistically achieving triplefunction goals; SF210 as thermally conductive insulating filler for polymers and RS925 as high wear resistant light colored rubber filler

8. Technical Inquiry (FAQ)

Q1: Can SF210 and RS925 be used together?

Yes. Both are highpurity quartzbased materials with good chemical compatibility. In scenarios requiring both thermal conductivity and wear resistance (such as highpower electronic device thermal pads, wearresistant thermally conductive coatings), they can be used in combination. SF210 is recommended as the primary component for thermal network construction, with RS925 synergistically enhancing surface wear resistance. Specific ratios should be determined experimentally based on target performance. This combination effectively delivers the benefits of a thermally conductive and electrically insulating filler alongside a high wear resistant light colored rubber filler, meeting complex design requirements.

Q2: How much of SF210’s thermal conductivity can be realized in composites?

12.5 W/K·m is the filler’s intrinsic thermal conductivity. The composite’s final thermal conductivity depends on the filler’s volume fraction, dispersion state, particle size distribution, and interfacial bonding quality. SF210’s surface activation treatment can improve fillermatrix interfacial bonding and reduce interfacial thermal resistance. As a general rule of thumb: at 50% volume loading, SF210 can increase epoxy resin’s thermal conductivity from 0.2 W/K·m to 35 W/K·m. Specific values require verification through actual formulations. In highfrequency electronic applications, its role as a thermally conductive insulating filler with dielectric loss 0.0018 for high frequency electronic applications becomes particularly valuable.

Q3: How does RS925’s wear resistance compare to conventional precipitated silica?

While precipitated silica has fine primary particle size (1050 nm), it exists predominantly as agglomerates (tens of micrometers) in rubber, with effective reinforcing particle size far exceeding primary particle size. RS925’s D50=2.22.8 μm represents the dispersed primary particle size, capable of maintaining submicron dispersion in rubber. At equivalent loading levels, RS925’s wear resistance can approach or reach N550 carbon black levels, while offering the high whiteness advantage that precipitated silica lacks. This makes RS925 an excellent high whiteness wear resistant quartz filler for replacing carbon black in colored rubber compounds and a reliable surface activated submicron silica powder for high wear resistance in light colored rubber products.

Q4: How do these products perform across different rubber systems?

Both products exhibit chemical inertness and are suitable for various rubber systems including NR, SBR, NBR, EPDM, CR, as well as epoxy resins, polyurethanes, silicone rubber, and other thermoset/thermoplastic systems. Surface activation treatment is optimized for the polarity of different matrices. Smallscale verification testing is recommended when transitioning matrices to confirm optimal formulation and process parameters. As a high purity quartz based reinforcing material, they provide consistent reinforcement across a wide range of polymer matrices, and their low impurity content ensures high purity quartz reinforcing filler with low impurity content for improved polymer weathering resistance, making them suitable for longterm outdoor applications. Additionally, for silicone rubber systems, SF210 acts as a High thermally conductive reinforcing filler for silicone rubber, boosting thermal management capabilities.

Resources & Contact

For tailored validation protocols and technical support addressing specific polymer systems, functional requirements, or particular service conditions, please contact the SaneZen technical team.

Email: yorichen@sanezen.com
Website: www.sanezenrubber.com