Stearic acid serves multiple critical functions in candle production and is a key functional additive in traditional paraffin-based candle formulations. Its primary applications are reflected in the following three areas:

1. Increase Melting Point and Hardness

Stearic acid (C₁₇H₃₅COOH) is a saturated long-chain fatty acid. Adding it to paraffin at 3%–8% significantly raises the melting point and room-temperature hardness of the blend, effectively reducing softening, deformation, and collapse risks during summer and transport while enhancing the candle's structural stability and upright hold.

II. Optimize Combustion Performance

Stearic acid offers excellent crystallization control, refining the crystal structure of paraffin to promote a more uniform and dense solidification. This enhances capillary wicking efficiency in the wick. Additionally, its oxygen-containing functional groups improve combustion completeness, reduce free carbon particle formation, significantly minimize soot and wax dripping, extend burn time, and enhance flame stability.

3. Enhanced Adhesion and Surface Finish

In pillar, container, and carved candles, stearic acid improves the wetting and adhesion of molten wax to wicks, glass containers, or mold walls, reducing demolding defects and edge shrinkage. Upon cooling, it imparts a fine, warm matte or soft-gloss finish, enhancing visual texture and tactile experience.

Note: Stearic acid dosage must be strictly controlled. Excess amounts (> 10%) can increase candle shrinkage, raise brittleness, and cause an acidic odor during burning. We recommend blending it with microcrystalline or palm wax to balance hardness, flexibility, and eco-friendliness. High-end artisan candles typically use industrial-grade, high-purity stearic acid (iodine value < 5, saponification value 190–205 mg KOH/g) to reduce soot and volatile organic compound (VOC) emissions, enhancing combustion safety and indoor air quality.

GUIZ Liutong 26-6-29