硬脂酸 stearic acid ( 十八酸, 己基癸醇硬脂酸酯)
很少單獨存在於自然界裡，並非化學合成物，常以甘油酯的形態存在，硬脂酸在自然界的分布很廣，
存在於許多植物性油脂和動物性油脂中。
動物脂肪中的含量比在植物油脂中的含量要高，如牛油中的含量可達24%，茶油為0.8%，棕櫚油為6%
，但可可脂中的含量高達34%。
硬脂酸實際上是45%硬脂酸和55%軟脂酸的混合物，並含有少量油酸，略帶脂肪氣味。
生產方式
動物油與水在高溫高壓下反應，使甘油三酸酯水解。不飽和植物油與氫氣加成得到。
硬脂酸在手工皂的應用主要是增加皂成品硬度。
添加硬脂酸的手工皂成品，有刺激皮膚的可能性，也比較容易阻塞毛孔。
硬脂酸添加比例為3%~5%。
建議計算氫氧化鈉時，計入硬脂酸皂化價
添加硬脂酸方式，純硬脂酸融點69.4度，可先與耐熱油脂熱融，如椰子油棕櫚油，一起加熱融好，再跟其他油ㄧ起融鹼。
根據皂友心得:如沒併入一起計算ins值，可將計算後約INS90的手工皂配上3%硬脂酸，就可有理想的硬度。
詢問商家的硬脂酸是那一種等級，應該是要買化妝品級的硬脂酸，購買三壓等級。
硬脂酸在手工皂的功能是增加皂的硬度。
操作方式 : 可先與耐熱的油一起熱融後再與其他的油一起融鹼，如融鹼後才加入，會加快Trace，需小心有假Trace情況發生。
硬脂酸（三壓級）
STEARIC ACID
Specs No.:703-28602 Product Code:SA1801 Product Form:Beads
| Property:Acid Value 酸值201-213Sapon Value 皂化值202-214Iodine Value 碘值1.0max.Titer(℃) 熔點54-56Colour(5 1/4″Lovibond) 顏色Yellow 2.0max. Red 0.5max. Composition(in%) Approx:C12(Lauric)& Lower1max.C14(Myristic)2max.C16(Palmitic)68max.C18(Stearic)30min.C20(Arachidic)1max.C18′(Oleic)1max. | ||
| Standard Packing: — 25kgs net. in PP Woven with PE inner bag –600kgs net. in jumbo bag | ||
| Test Method:AOCS |
硬脂酸（二壓級）
STEARIC ACID
Specs No.:703-28603 Product Code:SA1806 Product Form:Beads
| Property:Acid Value 酸值207-214Sapon Value 皂化值208-215Iodine Value 碘值3.0max.Titer(℃) 熔點53min.Colour(5 1/4″Lovibond) 顏色Yellow 5.0max. Red 1.5max. Composition(in%) Approx:C12(Lauric)& Lower1max.C14(Myristic)2max.C16(Palmitic)70max.C18(Stearic)29min.C20(Arachidic)1max.C18′(Oleic)3max. | ||
| Standard Packing: — 25kgs net. in PP Woven with PE inner bag — 600kgs net. in jumbo bag | ||
| Test Method:AOCS |
硬脂酸（一壓級）
STEARIC ACID
Specs No.:703-28604 Product Code:SA1810 Product Form:Beads
| Property:Acid Value 酸值185min.Sapon Value 皂化值186min.Iodine Value 碘值10max.Titer(℃) 熔點50min.Colour(Gardner) 顏色7Gardner max. Composition(in%) Approx:C12(Lauric)& LowerVariableC14(Myristic)VariableC16(Palmitic)VariableC18(Stearic)VariableC20(Arachidic)VariableC18′(Oleic)Variable | ||
| Standard Packing: — 25kgs net. in PP Woven with PE inner bag — 600kgs net. in jumbo bag | ||
| Test Method:AOCS |
硬脂酸（分餾三壓級）
STEARIC ACID
Specs No.:703-28605 Product Code:SA1840 Product Form:Beads
| Property:Acid Value 酸值200-212Sapon Value 皂化值201-213Iodine Value 碘值1.0max.Titer(℃) 熔點55-57Colour(5 1/4″Lovibond) 顏色Yellow 2.0max. Red 0.5max. Composition(in%) Approx:C12(Lauric)& Lower1max.C14(Myristic)2max.C16(Palmitic)60max.C18(Stearic)40min.C20(Arachidic)1max.C18′(Oleic)1max. | ||
| Standard Packing: –25kgs net. in PP Woven with PE inner bag –600kgs net. in jumbo bag | ||
| Test Method:AOCS |
硬脂酸（分餾三壓級）
STEARIC ACID
Specs No.:703-28606 Product Code:SA1850 Product Form:Beads
| Property:Acid Value 酸值198-210Sapon Value 皂化值199-211Iodine Value 碘值1.0max.Titer(℃) 熔點55-58Colour(5 1/4″Lovibond) 顏色Yellow 2.0max. Red 0.5max. Composition(in%) Approx:C12(Lauric)& Lower1max.C14(Myristic)2max.C16(Palmitic)53max.C18(Stearic)47min.C20(Arachidic)1max.C18′(Oleic)1max. | ||
| Standard Packing: –25kgs net. in PP Woven with PE inner bag –600kgs net. in jumbo bag | ||
| Test Method:AOCS |
硬脂酸（分餾三壓級）
STEARIC ACID
Specs No.:501-38608 Product Code:SAF1865 Product Form:Beads
| Property:Acid Value 酸值200-208Sapon Value 皂化值201-209Iodine Value 碘值1.0max.Titer(℃) 熔點57-61Colour(5 1/4″Lovibond) 顏色Yellow 3.0max. Red 0.5max. Composition(in%) Approx:C14(Myristic)0-1C16(Palmitic)30-38C18(Stearic)62-70C18′(Oleic)0-1 | ||
| Standard Packing: —20kgs net.in multiply kraft paper bags –25kgs net. in PP Woven with PE inner bag –600kgs net. in jumbo bag | ||
Test Method:AOCS |