Phosphorothioates

Phosphorothioates EP/AW Additives are oil‑soluble lubricant additives manufactured by Fanschem. Including alkyl phosphorothioates, branched‑chain modified products and low‑sulfur environment‑friendly variants, these liquid‑state additives form tenacious reactive tribofilms on metal contact surfaces under high‑load extreme‑pressure operating conditions, lessen interfacial friction and defend metal components from scratching, cold‑welding and abrasive wear. They deliver dependable high‑temperature thermal‑oxidative stability, low corrosivity toward non‑ferrous metals and excellent synergistic compatibility with thiazole‑based corrosion inhibitors, organic‑molybdenum friction modifiers and other common lubricant additives. Widely applied in automotive gear oils, metal‑working fluids, industrial gear lubricants, heavy‑duty hydraulic oils and machinery greases, Fanschem provides customizable product grades to meet international heavy‑duty lubrication and low‑emission standards, with stable bulk supply and skilled formulation‑optimization technical support for lubricant manufacturers across the globe.

What Are Phosphorothioates EP/AW Additives?

Phosphorothioates EP/AW Additives are ashless sulfur‑phosphorus composite lubricant additives built on phosphorothioate molecular skeleton, designed to deliver powerful extreme pressure and anti‑wear protection under heavy load, high temperature and impact friction conditions. Differing from single phosphate ester additives lacking sulfur synergistic effect, the full Fanschem phosphorothioate product range contains six mature grades: PSAIL 3890, PSAIL 6300, PSAIL 3530, PSAIL T309, PSAIL 2110 and PSAIL 2320. When bearing heavy mechanical loads, sulfur and phosphorus elements inside molecules decompose simultaneously and adsorb tightly on metal contact surfaces, forming dense S‑P composite tribofilms with strong adhesion. This protective layer effectively isolates steel friction pairs, suppresses surface scoring, pitting and metal seizure, while providing auxiliary antioxidant performance. With outstanding oil solubility and hydrolysis resistance, phosphorothioate additives have become mainstream EP raw materials widely recognized by global lubricant formulators for gear oils, metal working fluids and heavy‑duty industrial circulating oils.

Core Performance & Key Features of Phosphorothioates EP/AW Additives

S‑P Synergistic Extreme Pressure & Anti‑Wear Performance

The unique sulfur‑phosphorus dual‑component structure endows all phosphorothioate products with superior load‑bearing capacity far above single phosphorus‑based additives. The composite friction film remains intact under continuous shock load and high operating temperature, greatly reducing abrasion of gear sets, hydraulic plungers, bearings and metal workpieces. It efficiently avoids lubrication failure caused by boundary film rupture under peak torque and heavy‑duty working conditions.

Ashless Formula & Excellent Hydrolysis Stability

The whole series adopts zero metal ash molecular design, fully matching low‑emission, low‑SAPS lubricant development requirements. Optimized thiophosphate ester molecular structure greatly improves hydrolysis resistance, avoiding additive decomposition and performance attenuation in water‑containing metal working fluids. All six models are homogeneous transparent liquid, fully miscible with mineral oil, PAO and synthetic ester base stocks, without precipitation after long‑term low‑temperature storage. PSAIL 2320 specially optimizes molecular formula to achieve low copper corrosion, effectively preventing yellow metal discoloration.

Technical Advantages Over Ordinary Phosphate EP Additives

Compared with conventional single phosphate ester anti‑wear agents without sulfur components, Fanschem phosphorothioate additives possess prominent comprehensive technical strengths. The synergistic effect of sulfur and phosphorus greatly upgrades extreme pressure bearing capacity, suitable for harsh heavy‑load scenarios that single phosphate products cannot meet. The molecular structure boasts strong hydrolysis stability, applicable to water‑containing cutting and forming fluids with strict anti‑decomposition demands. Most grades feature mild corrosion to copper alloys, solving the copper blackening defect of high‑sulfur EP agents. They maintain perfect compatibility with organic molybdenum friction modifiers, triazole metal deactivators and dispersants without chemical antagonism. Long‑term operation generates fewer acidic byproducts, and lower recommended dosage effectively reduces overall formulation cost for lubricant manufacturers.

Main Applications of Phosphorothioates Lubricant Additives

Fanschem phosphorothioate series covers automotive and industrial full‑range lubricant blending demands. For automotive lubrication, it serves as core EP additive for heavy‑duty gear oil and transmission fluid to protect gear tooth surfaces under high torque impact loads. In industrial fields, it is widely added into high‑pressure hydraulic oil, long‑cycle compressor oil and multi‑purpose industrial grease. It is the preferred S‑P ashless additive for various cutting oil, drawing fluid and stamping metal working fluids. Meanwhile, it fits low‑phosphorus low‑emission lubricant formulas, and stably works on lubrication systems of construction, mining and agricultural heavy machinery enduring high temperature and heavy friction.

Technical Specifications & Product Parameters

Fanschem supplies six mature industrial‑grade phosphorothioate EP/AW additives with all physicochemical indicators adjustable according to customer customized formulas. PSAIL 3890 is dialkyldithiophosphate with balanced S‑P performance, the universal economical grade for general metal working fluids. PSAIL 6300 advanced dithiophosphate derivative enhances high‑temperature extreme pressure performance for high‑grade gear oil. PSAIL 3530 thiophosphate acrylate derivative owns excellent anti‑oxidation synergism for circulating industrial oils. PSAIL T309 solid triphenyl thiophosphate delivers ultra‑high load capacity for heavy forming fluids. PSAIL 2110 liquid triphenyl thiophosphate features good low‑temperature fluidity for all‑season industrial lubricants. PSAIL 2320 liquid thiophosphate ester optimizes copper passivation performance, ideal for formulas with strict non‑ferrous metal protection requirements. Customers can customize sulfur content, phosphorus content, kinematic viscosity and flash point to match exclusive formulation standards.

Phosphorothioates EP/AW Additives Manufacturer Strength

As a professional full‑series lubricant additive manufacturer, Fanschem phosphorothioate products gain long‑term trust from global lubricant factories and formulators. We own a complete product portfolio covering conventional dialkyldithiophosphates, acrylate modified thiophosphates and liquid/solid triphenyl thiophosphates, satisfying all ashless S‑P extreme pressure formulation needs. Strict whole‑process quality control including raw material incoming inspection and full‑index finished testing eliminates batch performance fluctuation. All products pass international environmental and safety certifications to support global cross‑border export business. Independent R&D laboratory continuously optimizes sulfur‑phosphorus molecular structures to adapt to low‑phosphorus green lubricant market trends. Factory direct supply without intermediate dealers, sufficient permanent inventory to sustain continuous bulk orders from worldwide clients.

Custom Formulation Solutions & Global Bulk Supply Service

Fanschem provides one‑stop supporting service for global lubricant manufacturers, distributors and formula engineers purchasing phosphorothioate additives. Complete OEM & ODM customization is available, including adjustment of sulfur‑phosphorus content, molecular alkyl chain and private label packaging specifications. Multiple flexible packaging options are offered: small trial barrels for laboratory formula debugging, standard iron drums for medium batch production and IBC bulk tanks for large industrial orders. Professional technical team supplies targeted dosage guidance, additive compatibility test reports and complete tribology extreme pressure performance data to accelerate customer formula development. We reply to quotation inquiries rapidly within working hours, cooperating with mature cross‑border logistics suppliers to guarantee stable and on‑time delivery of bulk phosphorothioate additive orders to all countries.