Industrial Grade 98% Butyl stearate CAS 123-95-5

 What is N-Butyl Stearate? How does it work?

N-Butyl stearate, also known as butyl stearate, n-butyl stearate, butyl octadecanoate, butyl stearate, or n-butyl stearate, has the chemical formula C22H44O2, a molecular weight of 340.58, CAS number 123-95-5, EINECS 204-639-5, and InChIKey ULBTUVJTXULMLP-UHFFFAOYSA-N. It is a long-chain fatty acid butyl ester formed by the esterification reaction of stearic acid (a C18 saturated fatty acid) and n-butanol, belonging to the stearate class of compounds. It is a typical industrial oily ester: at room temperature, it is a colorless to very pale yellow oily liquid (melting point approximately 20°C; below the melting point, it is a waxy solid), almost odorless or with a slight fatty odor, insoluble in water, soluble in mineral and vegetable oils, has an extremely low vapor pressure, and is chemically stable. With its lubricating, plasticizing, leveling, and hydrophobic properties, industrial-grade butyl stearate is widely used in plastics processing, coatings and inks, metal processing, textiles, sewing machinery, rubber, leather, papermaking, polishing, and mold release. It is a lubricating plasticizer for PVC, a core lubricating component in metal processing and textile oils, a leveling and lubricating agent for coatings and inks, and a universal mold release lubricant for various industries.

Basic information : Chemical formula C22H44O2 (structural formula CH3(CH2)16COOC4H9, i.e., an ester of stearic acid C17H35COOH and butanol C4H9OH); molecular weight 340.58; CAS number 123-95-5; EINECS 204-639-5; aliases: butyl stearate, butyl stearate, n-butyl stearate, butyl octadecanoate, butyl stearate, n-butyl stearate, butyl stearate, etc.

Structurally , butyl stearate is composed of an 18-carbon saturated stearic acid chain and a 4-carbon butyl group connected by an ester bond (-COO-): one end is a long-chain hydrocarbon (hydrophobic, flexible, lubricating), and the other end is a short butyl ester (lower melting point, improves compatibility), making it a flexible linear molecule as a whole.

Physically , butyl stearate is a colorless or very pale yellow liquid (above 20°C), and a waxy solid below its melting point. It is almost odorless or has a slight fatty odor (melting point approximately 19.5-27°C); boiling point approximately 343°C (760 mmHg, 220-225°C @ 25 mmHg); flash point approximately 160°C (closed cup); autoignition temperature approximately 355°C; density approximately 0.855 g/cm³ (25°C, 0.854-0.875); extremely low vapor pressure (approximately 5.8 × 10⁻⁶ mmHg @ 25°C), and almost non-volatile at room temperature; water solubility approximately 0.29% (25°C), almost insoluble in water, soluble in ethanol, ether, mineral oil, and vegetable oil; refractive index approximately 1.4328 (50°C); HLB value approximately 11 (oil/water emulsion); chemically stable, and does not easily deteriorate during long-term storage.

Chemically , butyl stearate is a saturated fatty acid ester (without carbon-carbon double bonds in the molecule, stable to oxygen and light, and not easily rancid or oxidized): the ester bond (-COO-) can undergo hydrolysis (slow hydrolysis back to stearic acid and butanol under acidic or alkaline conditions), saponification, and alcoholysis reactions, and is chemically inert under neutral conditions; the long-chain hydrocarbon part provides strong hydrophobicity, lubricity, and low surface energy, while the ester group provides a certain degree of polarity, making it compatible with mineral oils, vegetable oils, waxes, and most organic solvents, and compatible with polymers such as polyvinyl chloride (PVC); its low melting point and low glass transition contribute to its flexibility and low-temperature performance, while its low vapor pressure ensures that it does not volatilize or smoke under high-temperature processing and lubrication conditions.

Grading System : Butyl stearate is classified into several grades based on purity and application: Industrial grade (high purity, used as a plasticizer, lubricant, leveling agent, release agent, oil, etc., the main focus of this article); Cosmetic grade (used as a skin moisturizer and formulation aid, meeting cosmetic raw material specifications); Food grade (used as a flavor enhancer, seasoning, formulation aid, and food contact material component, meeting relevant FDA regulations); Research/Analytical grade (used as a solvent, standard, and laboratory reagent). Note: This article only discusses the industrial grade; the uses of other grades are only described here and not elaborated into separate entries.

Why does butyl stearate play these roles in industry? Its mechanism of action mainly includes the following:

Lubrication film formation mechanism : Long-chain fatty acid ester molecules can be oriented to form a continuous lubricating film on the surface of metals, fibers, plastics and leather, reducing the coefficient of friction and reducing wear and adhesion; low vapor pressure makes the oil film less prone to volatilization and failure under high temperature and high speed conditions, which is the basis for its use as a lubricant in metal processing, textile oil, sewing machine oil and release agent.

Plasticizing mechanism : Flexible linear molecules insert between polymer (especially PVC) molecular chains, increasing the inter-chain spacing, weakening the inter-chain forces, and lowering the glass transition temperature, making rigid plastics more flexible; its low melting point characteristics endow the products with excellent cold resistance and low-temperature flexibility, while improving processing lubrication and reducing roller sticking, making it a typical lubricating plasticizer.

Leveling and slipping mechanism : As a low surface tension component, it can be added to coatings, inks and paper coatings to reduce the surface tension of the coating film, improve leveling and give the surface a smooth feel and slipping effect, while helping pigment dispersion, inhibiting floating color and mottling, and reducing scratches and stickiness.

Hydrophobic and anti-sticking mechanism : Saturated long-chain hydrocarbons provide strong hydrophobicity, and after film formation, they have waterproof, moisture-proof, and anti-sticking isolation effects. When used in mold release systems, they can form an isolation film on the mold surface, making the products easy to separate. They are also used for waterproofing and stain prevention in polishing waxes and paper coatings.

Compatibility and solvent mechanism : The polarity of the ester group makes it compatible with mineral oil, vegetable oil, waxes, resins and most organic solvents. It can dissolve/disperse waxes and oily components, act as an oily carrier, and is also well compatible with polymers such as PVC and plasticizer systems, ensuring uniform and stable formulation.

All Applications of Industrial-Grade N-Butyl Stearate

1. PVC plasticizers (plastics industry)

Corresponding products: PVC wire and cable materials, artificial leather, floor covering, hoses, raincoats, shower curtains, films, shoe materials, toys, sealing strips, calendered products, plastic pastes, etc.

Why it works for this purpose: Butyl stearate is a typical lubricating plasticizer. Its flexible long chains insert between PVC molecular chains, lowering the glass transition temperature and making the product more flexible. When used in conjunction with a primary plasticizer (such as DOP/DINP), it can improve processing lubrication and reduce roller sticking. Its low melting point gives the product excellent cold resistance and low-temperature flexibility, while reducing the viscosity of the system, which is beneficial for calendering, extrusion and plasticized paste processing.

2. Coating and Ink Additives (Coating/Ink Industry)

Corresponding products: industrial paints, wood coatings, clear varnishes, screen printing inks, gravure inks, offset printing inks, inkjet inks, varnishes, powder coating additives, paint additives, etc.

Why it can be used in this application: As a low surface tension additive, butyl stearate is added to coating and ink systems to improve the leveling and surface smoothness of the coating film, impart slip and anti-blocking effects, help pigment wetting and dispersion, inhibit floating color and blooming, and at the same time provide flexibility and gloss. It is a commonly used component in paints and inks that takes into account both leveling and slip.

3. Metalworking fluids and forming lubricants (metalworking industry)

Matching products: Cutting fluid, stamping forming oil, drawing oil, tapping oil, rolling oil, grinding fluid, metal rust inhibitor, drawing lubricant, forging lubricant, machining oil, etc.

Why it can be used in this application Butyl stearate forms a tough, strong lubricating film on the metal surface which greatly reduces friction and wear between the tool and the workpiece, prevents tool sticking and scoring and provides boundary lubrication in severe forming operations such as stamping, stretching, drawing and forging. It has low vapour pressure so it will not evaporate and fail in high speed machining and it’s easy to clean and will not leave residues. It is a key lubricating ingredient in metalworking fluids and forming oils.

4. Textile oils and fiber lubricants (textile industry)

Corresponding products: chemical fiber spinning oil, yarn lubricant, knitting oil, weaving oil, sewing thread treatment agent, finishing softener, fiber antistatic component, twisting oil, etc.

Why it can be used for this purpose: Butyl stearate forms a uniform oil film on the surface of fibers and yarns, reducing friction between yarns and machine parts, and between yarns, reducing breakage and fuzz, improving weaving efficiency, and giving fibers a soft and smooth feel. It is a commonly used oiling component in spinning, weaving, twisting and finishing processes.

5. Sewing machine oil and lubrication for light industrial machinery (light industry)

Corresponding products: household sewing machine oil, industrial sewing machine oil, overlock machine oil, special lubricant for sewing machines, overlock machine oil, lubricant for light industrial machinery, lubricant for food machinery, etc.

Why it works for this purpose: Butyl stearate has moderate viscosity, extremely low volatility, does not corrode metals or stain fabrics, and can form a long-lasting lubricating film in precision parts such as sewing machine needle bars and bobbins, making the stitches smooth, reducing skipped stitches and thread breakage, while being clean and odorless. It is one of the most common ingredients in household and industrial sewing machine oils.

6. Rubber processing aids (rubber industry)

Corresponding products: tires, seals, hoses, rubber shoes, rubber mats, conveyor belts, miscellaneous rubber parts, rubber lubricants, rubber release agents, mold anti-sticking agents, etc.

Why it can be used in this application: Butyl stearate is used as a lubricant and release agent in the rubber compounding and moulding process to reduce the adhesion between the rubber compound and the rollers and moulds, to improve the release properties, to improve the flowability of the rubber compound, and to help disperse fillers. It has low volatility, which prevents the formation of bubbles and contamination during the vulcanisation process.

7. Leather fatliquoring and conditioning agents (leather industry)

Related products: leather fatliquoring agents, shoe polish, leather garment care oil, sofa care agents, leather brighteners, leather waterproofing agents, leather softeners, leather finishing aids etc.

Why it works for this purpose Butyl stearate is a fatliquoring component which penetrates into leather fibres, making leather soft, full and elastic, reducing creases and cracks, and forming a hydrophobic protective film on the surface of leather, improving water resistance and lustre. It is an oily component used in leather fatliquoring and care products.

8. Paper coating lubricant (paper industry)

Matching products: coated paper, coated paper, white cardboard, paper cup paper, label paper, release paper, coated packaging paper, coated printing paper, coated art paper, etc.

Why it can be used in this application Butyl stearate is used as a lubricant in the formulation of paper coating. It improves the rheological and levelling properties of the coating on the doctor blade and paper surface, reduces scratches, gives the coating smooth and glossy surface and good printability, and prevents the coating from sticky and powdery.

9. Polishing waxes and polishes (daily chemical/building materials industry)

Corresponding products: floor wax, car wax, furniture wax, shoe wax, stone polishing wax, metal polish, wood polish, leather shine, instrument panel polish, etc.

Why it can be used for this purpose: Butyl stearate has good compatibility with waxes, which can improve the gloss and uniformity of the wax film, reduce the brittleness of the wax film, make the polished surface bright and smooth and less prone to dust accumulation, and at the same time provide a certain degree of waterproof and stain-resistant effect. It is a common component of liquid and paste polishing waxes.

10. Mold Release Agent (Industrial)

Corresponding products: concrete release agent, plastic product release agent, rubber release agent, die casting release agent, fiberglass release agent, foamed product release agent, mold anti-sticking agent, cement product release agent, etc.

Why it can be used in this application: Butyl stearate forms a continuous hydrophobic lubricating film on the mold surface, making it easy to separate concrete, plastic, rubber, fiberglass and other products from the mold, reducing sticking, tearing and surface defects. Its water-resistant, non-corrosive and easy-to-clean properties are suitable for concrete pouring and plastic molding.

11. Lubricating oil additives (industrial lubrication)

Corresponding products: industrial gear oil additives, hydraulic oil additives, guide rail oils, chain oils, rust inhibitors, grease components, friction reducers, oiliness agents, metalworking lubricants, etc.

Why it can be used in this application: Butyl stearate is added to lubricating oils and greases as an oiliness agent and friction reducer. Its long-chain molecules adsorb onto the metal surface to form a strong oil film, which significantly reduces the coefficient of friction and improves lubrication performance under medium and low temperature and low load conditions. At the same time, it improves the rust prevention and wear resistance of the oil. It is a green and environmentally friendly lubricating additive.

12. Industrial Solvents and Oily Carriers (Fine Chemicals)

Corresponding products: wax solvents, pigment carriers, ink carriers, coating carriers, oil-based formulation additives, polishing paste carriers, adhesive additives, industrial cleaning agent components, etc.

Why it can be used in this application: The good oil solubility of butyl stearate allows it to dissolve and disperse oily components such as waxes, pigments, and resins, serving as a solvent and oily carrier in industrial formulations. It helps to evenly disperse components, adjust viscosity and flowability, while its low volatility and hydrophobicity improve the stability and film-forming properties of the formulation.

Summarize

Industrial grade N-Butyl Stearate (CAS 123-95-5) is a long chain fatty acid ester made from the esterification of stearic acid and butanol. It utilises the long chain hydrocarbon lubricating and hydrophobic properties and ester group compatibility to benefit a wide range of industrial segments such as plastics, coatings and inks, metal processing, textiles, sewing machinery, rubber, leather, papermaking, polishing and mould release. It is used as a lubricating plasticiser for PVC, a main lubricating agent for metal processing and textile oils, a levelling and lubricating agent for coatings and inks, and a general mould release agent and lubricating additive in a wide range of industries. Its knowledge of the molecular framework of “one long chain + one short ester group” explains why it can lubricate, plasticise, level and hydrophobize simultaneously. This is exactly why it spans more than ten industrial sub-applications and becomes an industrial oily ester versatile.

Safety Advice

Butyl stearate industrial grade is used in non-food applications such as plastics, metal processing and textiles. It is a flammable liquid with a flash point of about 160°C. The following precautions should be taken in handling it. Keep away from fire and high temperature during storage and transportation. Heating and decomposition will produce irritating fumes. Provide adequate ventilation. Prolonged skin contact may cause defatting, use oil-resistant gloves and avoid inhalation of oil mists during processing. In case of spillage, use absorbent material. Waste oil and oily waste should be collected and disposed of in accordance with hazardous waste regulations and should not be discharged directly into water bodies. Its vapour pressure and volatility are very low, so under normal conditions of use the risk of exposure is very low. It is environmentally compatible and biodegradable. It is not an environmental persistent pollutant. Industrial Users shall be operated according to Material Safety Data Sheet (SDS) requirements and stored in a cool, dry place with containers tightly closed.