In stearic acid procurement, SINARMAS (PT. Soci Mas) is frequently referenced for three grades: FAB, FAH, and FAR. All are palm-based stearic acids with similar appearance and packaging, yet they differ significantly in refining level, key specifications, and application suitability. This guide consolidates their technical differences into a clear comparison to help procurement and technical teams quickly select the right grade.
I. Common Foundation: Palm-Based Stearic Acid from the Same Source
FAB, FAH, and FAR are produced by SINARMAS (PT. Soci Mas) using palm oil as the raw material. Available in pellet/granule form with 25KG loose packaging, these products are plant-based, non-GMO, and certified Halal and Kosher. The difference among them lies not in the raw material source but in the number of pressing and refining stages, which determines their respective quality control standards.
- FABTriple-Pressed Stearic Acid
- FAH: Triple Pressed Stearic Acid, a high-grade specification of triple-pressed stearic acid.
- FARTechnical Grade Stearic Acid
2. Purity Differences: Triple-Press Refined vs. Crude Processing
FAB and FAH are both triple-pressed, high-purity grades with low unsaturated and impurity content due to three-stage refining. FAR is an industrial grade, produced with fewer processing steps as a crude product; it has a darker color and higher impurity levels.
This difference is directly reflected in the Iodine Value and Color metrics: FAB and FAH both have an Iodine Value of 0.1, while FAR reaches 1.0. For color, FAB is APHA 20, FAH is APHA 10, and FAR reaches APHA 110.
III. Key Metrics Comparison Table
| Metrics | FAB | FAH | FAR |
|---|---|---|---|
| Refining Method | Triple-pressed High Purity | Triple-Pressure High-Spec | Industrial-grade |
| Iodine Value (Measured / Upper Limit) | 0.1 / 0.5 | 0.1 / 0.3 | 1.0 / 2.0 |
| Color APHA (Measured / Limit) | 20 / 80 | 10 / 50 | 110 / 250 |
| Lovibond Color | — | 0.3Y / 0.1R | — |
| Palmitic Acid C16 | Approximately 60% | Approximately 59.7% | 47.3% |
| Stearic Acid C18:0 | Approximately 39% | Approximately 39.5% | 50.8% |
| Heat Stability (205°C / 2h) | — | 90 max (explicit assessment) | — |
| Product Positioning | High-Purity Three-Pressure | Premium Triple-Pressure | Industrial-grade |
The values in the table are typical measured values from technical documentation. Actual procurement should be based on the COA test report provided with each batch.
4. Iodine Value and Color: Two Often Overlooked Metrics
Iodine ValueReflects the content of unsaturated double bonds in fatty acids. A lower iodine value indicates lower unsaturation and higher oxidative stability. The maximum iodine values are 0.5 for FAB, 0.3 for FAH (the stricter of the three), and 2.0 for FAR. For systems with long storage periods or high-temperature processing, selecting grades with stricter iodine value controls is recommended for better stability.
ChromaticityDetermine suitability for light-colored or transparent products. FAH has a pale color (APHA 10), FAB is next (APHA 20), and FAR has a darker hue (APHA 110). Therefore, FAH and FAB are suitable for light-colored, transparent, or high-purity color applications, while FAR is appropriate for scenarios where color requirements are less stringent.
5. How does carbon chain composition determine application direction?
Differences in carbon chain composition are the key factor determining application direction.
- FARStearic acid C18:0 is present in high content, reaching 50.8%, while palmitic acid C16 accounts for 47.3%. The long fatty acid chains, hard crystalline structure, and high melting point make it ideal for products requiring high hardness and melting point.
- FAB: Palm fatty acid C16 accounts for 60%, stearic acid is approximately 39%. The system is relatively soft with excellent flexibility and superior low-temperature performance.
- FAH: The component content falls between the two extremes (C16 is approximately 59.7%, C18 is approximately 39.5%), with narrow specification limits, resulting in more consistent batch-to-batch performance.
6. Three Additional Advantages of FAH Over FAB
Both are high-purity Grade 3. FAH is the higher-specification product, with three key differences:
- Stricter Iodine Value Limits: FAH is 0.3 max, FAB is 0.5 max.
- Lighter color: FAH measured APHA 10, FAB is APHA 20.
- FAH specifies a maximum thermal stability of 205°C for 2 hours, meeting stricter requirements for high-temperature applications and suitable for heat-resistant processing systems.
7. Scenario-Based Selection Recommendations
FAR (Industrial Grade)
High iodine value, darker color, and low cost. Contains high C18 content, is hard, and has a high melting point. Suitable for industrial applications where color is not critical but cost-effectiveness is key, such as rubber processing, standard candles, saponification feedstock, industrial lubricants, tires, and rubber additives requiring high hardness or melting point without strict color requirements.
FAB (High-Purity Tri-Pressure)
Light color, low iodine value, high C16, flexible system, and excellent low-temperature performance. Ideal for personal care (soaps, cosmetic creams), food-grade additives, plastic and rubber stabilizers, and light-colored candles—applications requiring light color, smooth skin feel, and high oxidative stability.
FAH (Premium Triple-Pressure)
Light color, low iodine value, and excellent thermal stability. Ideal for high-end cosmetics, pharmaceutical excipients, optical-grade or food-contact materials, and high-temperature processing systems requiring superior color purity and thermal stability.
VIII. Procurement and Testing Support
All three grades are available with batch-specific COA reports, and sample requests or specification verification are supported. For quotes, batch specifications, or selection guidance, visitFAQFor detailed item instructions, contact a business representative: 025-52291633 / 18951611983 / 18915933688.