CASHEW OIL

Cashew Oil, also known as Cashew Nut Shell Oil, Cashew Shell Oil, Cashew Nut Shell Liquid, CNSL and CAS No. 8007-24-7, is a naturally derived raw material obtained from the honeycomb structure in the shell of the cashew (Anacardium occidentale) fruit. It consists of phenolic lipids such as cardanol, cardol and anacardic acid, and is used as a bio-based phenol source especially in brake lining and clutch friction materials, phenolic resins, epoxy curing agents and rubber compounds.
Cashew Nut Shell Oil, or CNSL for short, is one of the rare plant-based raw materials that, thanks to its phenolic structure with a long aliphatic side chain, can polymerize, form resins with formaldehyde and be modified into a large number of derivative chemicals; in industry it is regarded as a renewable alternative to petroleum-based phenols in terms of flexibility, water repellency, heat resistance and chemical resistance.
Resin and composite systems containing Cashew Oil in their formulations form a hard, flexible and heat-resistant structure because the phenolic ring and the double bonds in the side chain can react together.
Using this Cashew Nut Shell Liquid based raw material in a formulation can provide functional benefits such as increasing friction stability in the final product, flexibilizing the resin, improving resistance to moisture and water, and replacing part of the petroleum-based components with bio-based content.
Cashew Oil shows reactivity through both phenol chemistry and drying oil chemistry, thanks to its central phenolic ring and the fifteen-carbon side chain with varying degrees of unsaturation attached to this ring in the meta position.
Cashew Nut Shell Liquid reacts with aldehydes, amines and epoxy groups to bond into the resin network, contributing to toughness, adhesion and durability in formulations where CNSL is used.

Cashew Nut Shell Oil is a functional raw material used to help reduce problems such as heat-related performance loss in friction materials, brittleness in resin systems, weakness against moisture in coatings and insufficient curing at low temperatures.
CNSL reacts in a controlled manner with phenolic and epoxy systems, helping to maintain the mechanical strength, chemical resistance and long-term thermal stability of the product.
In resin, rubber and coating formulations, it is a functional and renewable component that, thanks to its reactive structure and versatile chemistry, helps keep processability, flexibility and durability at the desired level.
Systems containing Cashew Oil support the development of brake linings that operate more quietly and consistently for the end user, moisture-resistant coatings and products with increased bio-based content.

Cashew Nut Shell Liquid is an effective natural raw material that, thanks to its phenolic structure, long hydrophobic side chain and double bond content, can support multiple performance properties simultaneously in resin and composite systems.
Thanks to its renewable source and versatile reactivity, Cashew Nut Shell Oil helps meet multiple needs such as flexibility, heat resistance, water repellency and chemical resistance, compared with alternatives that focus on a single property.
It can be used in brake linings, clutch discs, epoxy floor and marine coatings, laminates, foundry core binders and rubber compounds, and can also serve as a starting raw material in the production of surfactants, antioxidants, polyols and epoxy diluents.
CNSL helps the formulator develop durable and sustainable systems while offering the manufacturer practical benefits such as good processability, low-temperature curing capability and bio-based content.

WHAT IS CASHEW OIL?

Cashew Oil, also known in industrial chemistry as Cashew Nut Shell Oil, or CNSL for short, is a dark brown to black, viscous, phenolic natural liquid found in the spongy honeycomb tissue between the outer and inner shell of the cashew nut, the fruit of the cashew tree (Anacardium occidentale). Cashew Oil is also referred to by names such as Cashew Nut Shell Liquid, Cashew Nut Shell Oil, Cashew Nutshell Liquid, Cashew Shell Liquid and Anacardium Occidentale Nut Shell Oil. Depending on the extraction method, it is available in two main commercial forms: Natural CNSL (natural cashew nut shell oil) and Technical CNSL (technical cashew nut shell oil).
In particular, depending on its cardanol, cardol and anacardic acid ratio, iodine value, viscosity, polymerizable matter content, moisture and ash content, it can show different reactivity and processing behavior in different applications. Expressions such as CNSL Oil, Cashew Shell Oil, Cardanol Oil, Friction Grade CNSL and Technical Grade CNSL are terms that may be encountered in technical and commercial searches. However, these expressions do not always describe the same product. For example, although Natural CNSL and Technical CNSL are obtained from the same source, they are two separate commercial forms with different compositions and different chemical behavior.
In commercial language, the term "Cashew Oil" may also be used for Cashew Kernel Oil (Anacardium Occidentale Seed Oil), which is obtained from the cashew kernel for edible and cosmetic purposes. Cashew kernel oil is a light yellow, triglyceride-based vegetable oil and is chemically entirely different from phenolic Cashew Nut Shell Oil. The product covered on this page is Cashew Nut Shell Oil, i.e. Cashew Nut Shell Liquid, used in industrial applications. Therefore, which product is meant must always be clarified in ordering and quotation processes.
Furthermore, not all Cashew Nut Shell Liquid products on the market have the same physical properties or the same processing behavior. The product's cardanol ratio, anacardic acid content, iodine value, viscosity, moisture and volatile matter content, ash content and polymerization time can significantly change its performance. Therefore, it should not be assumed, based only on the product name "Cashew Oil" or "CNSL", that products from different manufacturers are technically interchangeable.
Cashew Nut Shell Oil does not consist of a single molecule; it is a mixture of closely related phenolic lipids. Among the main components, cardanol (3-pentadecylphenol derivatives) is a monohydric phenol, cardol is a dihydric resorcinol derivative, and anacardic acid is a salicylic acid derivative carrying a carboxyl group. All of these components have a fifteen-carbon side chain attached to the ring, and this side chain may be saturated or contain one, two or three double bonds. This structural feature is the basis for Cashew Oil's ability to behave both as a phenol and as an unsaturated oil.
Cashew Nut Shell Liquid can be used particularly as a binder and friction dust raw material in friction materials, as a modifier in phenolic and epoxy resins, in the production of phenalkamine-type epoxy curing agents, as a processing aid in rubber compounds, and as a reactive component in the coating, laminate and foundry industries. Depending on the application, more specific product definitions such as Technical CNSL, distilled cardanol or polymerized CNSL may be used.
The performance of Cashew Nut Shell Oil does not depend only on its source. Component distribution, iodine value, viscosity, moisture, ash and volatile matter content, polymerization time and foreign matter content can affect the formulation result. Therefore, two CNSL products sold under the same name may not have the same reaction rate, resin yield, viscosity behavior or final product performance.

Depending on the quality grade, Cashew Oil can be used in brake linings and clutch discs, friction dusts, phenolic resins, epoxy curing agents, marine and floor coatings, rubber compounds, laminates, foundry core binders, surfactant and antioxidant production, and wood protection applications. Its most common uses are friction materials for the automotive sector and phenolic and epoxy resin systems.

Thanks to this dual reactivity potential in its chemical structure, Cashew Nut Shell Liquid undergoes a condensation reaction through the phenolic ring, especially when it encounters aldehyde sources such as formaldehyde or hexamine; the double bonds in the side chain provide additional polymerization under the effect of heat and catalysts. This natural raw material, defined in industry by various functional names such as CNSL resin, CNSL friction dust and cardanol based curing agent, makes it possible to flexibilize hard and brittle phenolic structures while maintaining heat resistance. This structure supports the thermal stability of friction materials, the impact resistance of resins, the water and chemical resistance of coatings and the processability of rubber products.
Commercially available Cashew Nut Shell Oil products come in different compositions depending on the temperature applied during production. Natural CNSL obtained by cold pressing or solvent extraction contains a high proportion of anacardic acid, while in Technical CNSL, obtained by the hot method during shell roasting, anacardic acid is largely decarboxylated and converted into cardanol. This natural raw material, appearing as a dark brown viscous liquid, can vary in terms of reaction rate, resin yield and final product properties depending on technical parameters such as iodine value, viscosity, cardanol ratio and polymerization time. In conclusion, Cashew Oil is a fundamental phenolic raw material of renewable origin used in a wide range of applications from brake linings to marine coatings.

COMMON PRODUCT AND CHEMICAL NAMES:

Cashew Oil

Cashew Nut Shell Liquid

CNSL

Kaju Kabuğu Yağı

Kaju Yağı

Kaju Kabuk Sıvısı

Cashew Nut Shell Oil

Cashew Nutshell Liquid

Cashew Nutshell Oil

Cashew Shell Oil

Cashew, nutshell liq.

Anacardium Occidentale Nut Shell Oil

Anacardium Occidentale Nutshell Liquid

Natural CNSL

Technical CNSL

Technical Grade CNSL

Friction Grade CNSL

CNSL Oil

Cardanol Rich Oil

Cardanol Oil

CNSL Resin Raw Material

Bio-based Phenol

Phenolic Lipid Mixture

Some of these names express the chemical identification, some the extraction method, and others the field of use or commercial function. For example, Cashew, nutshell liq. indicates the official substance name used in registrations, while CNSL is the common abbreviation. Natural CNSL and Technical CNSL refer to the compositional difference depending on the extraction method. Friction Grade CNSL and Cardanol Rich Oil, on the other hand, are commercial designations referring to the product's field of use or component profile.
It is important to evaluate the CAS number used for Cashew Oil together with the actual identity of the product. CAS No 8007-24-7 and EC No 232-355-4 are listed in sources for Cashew Nut Shell Oil. Since the same CAS number may also be associated with cashew kernel oil in some commercial documents, whether the product is shell oil or kernel oil should be checked through the documents at the time of purchase. Cardanol purified by distillation may be offered as a separate product with different chemical identifications.

CAS NO, EC / EINECS NO AND CHEMICAL IDENTIFICATION

Product name: Cashew Oil / Cashew Nut Shell Liquid

Common abbreviation: CNSL

Chemical name: Cashew, nutshell liq. (Anacardium occidentale shell oil)

CAS No: 8007-24-7

EC / EINECS No: 232-355-4

Molecular formula: There is no single formula; it is a natural mixture. The formula of the main component cardanol varies between C₂₁H₃₀O and C₂₁H₃₆O depending on the unsaturation of the side chain.

Molecular weight: Approximately 298–304 g/mol for the main component cardanol

Chemical class: Natural phenolic lipid mixture / plant-derived alkylphenol

Main functions: Bio-based phenol source, resin modifier, friction material binder, curing agent and derivative chemical raw material

Cashew Nut Shell Liquid is a natural mixture classified among substances of variable composition or complex substances of biological origin. Therefore, it is defined by the distribution of its main components rather than a single molecular formula and molecular weight.
CAS No 8007-24-7 and EC No 232-355-4 for Cashew Nut Shell Oil are listed in various official and technical sources. This registration is the general identification covering both natural and technical CNSL.
However, using a single CAS number for Cashew Oil may not be sufficient for every commercial product. Since the cardanol, cardol and anacardic acid ratio directly affects reactivity and processing behavior, the full definition of the product and the relevant technical documents should be checked during purchasing.

Industrial Cashew Nut Shell Oil is not used as a food or pharmaceutical raw material. Although records relating to shell oil may exist in cosmetic databases, industrial CNSL should not be used in personal care products due to its high irritation and sensitization potential. The product's field of use is limited to industrial resin, composite, coating and rubber applications.
Rather than being considered as a single pure component, Cashew Oil should be treated commercially as a mixture mostly consisting of cardanol, cardol, anacardic acid, 2-methyl cardol and polymeric material. Therefore, even in products with the same CAS number, the component distribution can change technical performance.

CHEMICAL STRUCTURE AND MOLECULAR PROPERTIES OF CASHEW OIL

Cashew Oil consists of phenolic lipids with an aromatic phenol ring at the center and a fifteen-carbon aliphatic side chain attached to this ring in the meta position. This structure gives the molecule polar and reactive character at one end and apolar and hydrophobic character at the other.
The structural differences between the main components can be summarized as follows: cardanol carries a single hydroxyl group on the ring; cardol has a resorcinol structure with two hydroxyl groups on the ring; anacardic acid contains a carboxyl group in addition to the hydroxyl group; and 2-methyl cardol is the methyl-substituted derivative of cardol.
The side chain consists of a mixture of saturated (pentadecyl), monounsaturated (monoene), diunsaturated (diene) and triunsaturated (triene) forms. These double bonds give Cashew Nut Shell Oil oxidative and thermal polymerization capability similar to drying oils. A high iodine value is an indicator of this unsaturation.

The technical performance of Cashew Nut Shell Liquid cannot be understood from its chemical structure alone. Component ratio, iodine value, viscosity, polymeric matter content, moisture, ash and volatile matter content are important parameters that determine product behavior.
In natural CNSL, anacardic acid is generally the dominant component. In technical CNSL, however, the heat applied during shell roasting removes the carboxyl group of anacardic acid as carbon dioxide, and the component is converted into cardanol. Therefore, cardanol is the dominant component in technical CNSL; cardol and some polymeric material are also present.
The long side chain gives phenolic resins internal flexibility (internal plasticization) and reduces water absorption. This property is one of the main reasons why CNSL-modified resins are tougher, less brittle and more moisture-resistant than pure phenol-formaldehyde resins.

PHYSICAL AND CHEMICAL PROPERTIES OF CASHEW OIL

Cashew Oil is generally a dark brown to black, viscous liquid with a characteristic odor. Physical appearance may vary depending on the extraction method, component distribution, storage time and commercial grade.

General technical properties:

Physical appearance: Dark brown to black, viscous liquid

Chemical character: Natural phenolic lipid mixture

Main components: Cardanol, cardol, anacardic acid, 2-methyl cardol and polymeric material

CAS No: 8007-24-7

EC / EINECS No: 232-355-4

Density: Generally in the range of approximately 0.94–0.97 g/cm³

Viscosity: Grade-dependent; for technical CNSL, on the order of a few hundred cP at 25 °C and specified as an upper limit in the specification

Iodine value: High; values of generally 200–250 g I₂/100 g and above are specified for technical CNSL

Moisture content: Generally specified below 1%

Ash content: Generally specified below 1%

Volatile matter: Grade-dependent; generally specified with a low upper limit

Flash point: High; generally above 200 °C

Solubility in water: Practically insoluble

Organic solvents: Miscible with alcohols, ketones, aromatic and aliphatic hydrocarbons

Reactivity: Can react with aldehydes, amines, epoxies, isocyanates and under oxidizing conditions

The physical properties of Cashew Oil can vary significantly depending on the product's extraction method. Natural CNSL may show a higher acid value and different viscosity behavior, while Technical CNSL, thanks to its higher cardanol content, may offer more predictable reactivity in resin and friction applications.
Iodine value is one of the most important parameters of Cashew Nut Shell Oil in terms of technical performance. This value indicates the unsaturation in the side chain and directly affects thermal polymerization, drying and resin formation behavior. Two CNSL products with different iodine values may give different polymerization rates and different final hardness under the same conditions.
Polymerization time is a practical quality test showing how long it takes for the product to gel at a given temperature in the presence of a catalyst. It is used especially by friction dust and resin manufacturers to check batch-to-batch consistency of reactivity.
These values are for general technical introduction; they should not be used as the binding specification of the product to be purchased. In particular, parameters such as iodine value, viscosity, density, moisture, ash, volatile matter, polymerization time, cardanol ratio and foreign matter content should be checked against the supplier's current TDS and COA documents.

HOW DOES CASHEW OIL WORK AT THE MOLECULAR LEVEL?

The main effect of Cashew Oil in formulations occurs through the participation of the phenolic ring and the double bonds in the side chain in the polymer network via different reaction mechanisms.
The ortho and para positions of the phenolic ring undergo condensation reactions with aldehyde sources such as formaldehyde or hexamine, forming methylene bridges. This mechanism forms the basis of CNSL-formaldehyde resins and CNSL-modified phenolic resins.
The phenolic ring also undergoes a Mannich reaction with formaldehyde and an amine to form epoxy curing agents called phenalkamines. Thanks to their long hydrophobic side chain, these curing agents are known for their ability to cure at low temperatures and in humid environments.
The double bonds in the side chain polymerize under heat, acid catalysts or oxidative conditions, forming additional crosslinks. This property enables Cashew Nut Shell Oil to harden in friction dust production and in drying coating systems.

The functions of Cashew Oil at the molecular and polymeric level can differ depending on the application:

Participating in the phenolic resin network

Modifying the resin by imparting toughness through internal flexibility

Polymerizing and hardening in friction dust production

Serving as a starting raw material for phenalkamine curing agents

Increasing water and moisture resistance

Supporting chemical and corrosion resistance

Improving processability in rubber compounds

Providing a source for antioxidant and stabilizer derivatives

Being converted into surfactant and polyol derivatives

Increasing the bio-based content ratio

The long side chain flexibilizes the structure by creating space between polymer chains, while the aromatic ring maintains thermal stability. This dual structure allows a balanced performance between hardness and flexibility in CNSL-based products.
The rate and degree of the reaction are directly related to the CNSL grade, aldehyde or amine ratio, catalyst type, temperature and time. Therefore, Cashew Nut Shell Liquid should not be evaluated on its own, but together with the resin, curing agent and catalyst system with which it is used.
Since the phenolic ring and the hydrophobic side chain coexist in the post-cure structure, CNSL-based resins and coatings show good resistance to water absorption and many chemicals. For this reason, Cashew Nut Shell Oil derivatives are preferred in coatings and composites operating in humid and aggressive environments.
However, it should not be assumed that Cashew Oil will give the same reaction and performance result in every resin system. The CNSL grade used, iodine value, cardanol ratio, secondary raw materials and process conditions should be evaluated through laboratory trials.

IN WHICH SECTORS IS CASHEW OIL USED?

Thanks to its phenolic structure and renewable source, Cashew Oil is a versatile raw material used in various industrial fields, primarily automotive friction materials and the resin sector. The purpose of use may vary according to the product's grade, composition and formulation system.

Main areas of use:

Brake lining and brake shoe production

Clutch discs and friction materials

Friction dust production

Phenolic resin modification

Epoxy curing agents (phenalkamines)

Marine, floor and anti-corrosion coatings

Varnishes and surface coatings

Rubber compounds and the tire industry

Laminates and composite materials

Core binders in the foundry industry

Adhesive and sealant systems

Surfactant and emulsifier production

Antioxidant and stabilizer production

Bio-based polyols for polyurethane systems

Epoxy reactive diluents

Wood protection and insect-protective applications

The most common use of Cashew Oil is in friction dusts used in brake lining and clutch materials and in CNSL-modified phenolic resins. These products are preferred especially in applications requiring stable friction performance under high temperature, pressure and wear conditions.
The performance each sector expects from Cashew Nut Shell Oil is different. For example, a friction material manufacturer focuses on thermal stability and consistency of the friction coefficient, while an epoxy curing agent manufacturer may prioritize high cardanol purity and low color value, and a rubber manufacturer may prioritize processability and compound compatibility.

USE OF CASHEW OIL IN FRICTION MATERIALS AND RESINS

In friction material formulations, Cashew Oil is polymerized into friction dust and used together with a phenolic resin binder. This combination is commonly referred to in the industry as "CNSL friction dust" or "cashew nut shell oil based friction dust".

Possible functions of Cashew Oil in friction materials and resins are:

Helping keep the friction coefficient stable

Reducing heat-related performance loss (fade)

Helping reduce noise and vibration

Supporting wear resistance

Imparting flexibility to the phenolic resin

Improving the impact resistance of the resin

Reducing water and moisture absorption

Providing stable burning behavior as an organic component at high temperatures

CNSL-based friction dusts and modified phenolic resins can be used particularly in passenger and commercial vehicle brake linings, brake shoes, clutch discs and industrial brake systems.
In friction dust production, Cashew Nut Shell Oil is generally polymerized with an aldehyde source and a catalyst, then fully cured by heat treatment and ground to the desired particle size. The acetone extract, ash content, thermal loss and particle size of the resulting dust are decisive for quality.
In modified phenolic resins, Cashew Nut Shell Oil is used in place of part of the phenol, increasing the flexibility, toughness and moisture resistance of the resin. The usage ratio is determined according to the targeted balance of hardness and flexibility.
When selecting CNSL for friction and resin applications, iodine value, viscosity, polymerization time, moisture, ash and cardanol ratio should be evaluated.
Whether a Cashew Nut Shell Oil product will give the same result in every formulation should not be inferred from the name "Cashew Nut Shell Liquid" alone. Trials should be conducted based on process conditions and targeted performance.

EPOXY, COATING AND SPECIALTY RESIN APPLICATIONS OF CASHEW OIL

Cashew Oil and the cardanol obtained from it can be used, in a suitable quality grade, as a reactive component or modifier in epoxy curing agents, marine and floor coatings, varnishes and specialty resin systems.

Functions for which Cashew Nut Shell Oil can be evaluated in these applications include:

Providing low-temperature curing through phenalkamine curing agents

Supporting curing on damp surfaces and underwater

Increasing the water and chemical resistance of the coating

Supporting corrosion protection

Improving flexibility and adhesion in epoxy systems

Providing reactive diluents through derivatives such as cardanol glycidyl ether

Increasing the bio-based content ratio

When purchasing Cashew Oil or cardanol for epoxy and coating applications, the following should be checked:

Cardanol purity and component distribution

Color (especially for light-colored coatings)

Iodine value

Viscosity

Moisture and volatile matter content

Current technical specification

Certificate of analysis (COA)

Safety data sheet (SDS)

Manufacturer and batch traceability

Compliance and certification documents where required

The dark color of technical CNSL may be limiting in some coating applications. Therefore, distilled cardanol or lighter-colored derivatives may be preferred in systems where a light color is expected.
Likewise, a CNSL product suitable for friction material cannot automatically be said to be suitable for epoxy curing agent production. For each application, the relevant quality requirements and manufacturer documents should be checked.

IS CASHEW OIL USED IN COSMETIC, FOOD AND PHARMACEUTICAL APPLICATIONS?

Industrial Cashew Oil, i.e. Cashew Nut Shell Oil (CNSL), should not be used as a raw material in cosmetic, personal care, food or pharmaceutical products. Components in the shell oil such as anacardic acid and cardol can have strong irritant and sensitizing effects on the skin.
At this point, the difference between Cashew Nut Shell Oil and Cashew Kernel Oil is particularly important. The oil obtained from the cashew kernel is a light yellow triglyceride oil rich in oleic and linoleic acid, and its INCI name is known as Anacardium Occidentale (Cashew) Seed Oil. While this product can be used in food and cosmetics, industrial CNSL is not used for these purposes.
In cured resin or composite structures, CNSL components are chemically bound to the polymer network. Nevertheless, if CNSL-based products are planned for use on food-contact surfaces or in applications with high human contact, the compliance of the final product with the relevant regulations should be evaluated separately.
Companies looking for cashew oil for cosmetic or food purposes need to evaluate Cashew Kernel Oil products specifically produced for these applications and compliant with the relevant regulations. In products using cashew kernel oil, it is also important to consider the necessary labeling and warnings regarding nut allergies.

INDUSTRIAL APPLICATIONS OF CASHEW OIL

Due to its phenolic structure, high unsaturation and renewable source, Cashew Oil is an important functional raw material used in many industrial systems.

The following functions may stand out in industrial CNSL applications:

Being a bio-based phenol source

Resin modification

Friction dust production

Being a curing agent raw material

Imparting flexibility and toughness

Water and moisture resistance

Chemical resistance

Corrosion protection support

Thermal stability

Acting as a processing aid

Antioxidant properties

Surface activity (through its derivatives)

Derivative chemical production

In the automotive sector, Cashew Nut Shell Oil helps provide consistent friction performance and quiet operation in brake and clutch systems. For this reason, it is among the key organic raw materials for friction material manufacturers.
In the coatings sector, CNSL derivatives are used to provide durability on surfaces exposed to moisture and chemicals, especially marine structures, tank interiors, concrete floors and pipelines.
In rubber, laminate and foundry applications, Cashew Nut Shell Liquid can be evaluated to improve processability, increase binder performance and replace part of the petroleum-based components with renewable content.

The following should be evaluated when using Cashew Oil in industrial systems:

CNSL grade (Natural or Technical)

Cardanol, cardol and anacardic acid ratio

Iodine value

Viscosity

Polymerization time

Aldehyde, amine or curing agent ratio

Catalyst type and amount

Reaction temperature and time

Moisture and ash content

Volatile matter content

Color

Performance requirements of the final product

WHICH PROBLEMS CAN CASHEW OIL HELP SOLVE?

Cashew Oil can help solve various problems related to thermal stability, brittleness, moisture resistance and low-temperature curing in friction material, resin, coating and rubber systems. However, its effect depends on the grade used, usage ratio and process conditions.

Heat-related performance loss in brake linings

Some friction materials may show a decrease in friction coefficient at high temperatures. CNSL-based friction dusts, by exhibiting controlled thermal behavior as an organic component, can help keep friction performance more stable.
However, the use of Cashew Nut Shell Oil alone does not guarantee superior braking performance under all conditions. The binder resin, fibers, fillers and abrasives should be evaluated together.

Brake noise and vibration

Friction dusts can contribute to reducing noise and vibration by increasing the damping properties of the friction material.

Brittleness in phenolic resins

Pure phenol-formaldehyde resins can be brittle despite their high hardness. Thanks to its long side chain, CNSL can help increase impact resistance and toughness by imparting internal flexibility to the resin.
However, high usage ratios can reduce thermal resistance and hardness; the optimum ratio should be determined through trials.

Insufficient curing at low temperatures and in humid environments

Conventional amine-cured epoxy systems may cure slowly at low temperatures and create surface defects in humid environments. Phenalkamine curing agents obtained from Cashew Nut Shell Oil can help achieve curing at low temperatures and on damp surfaces.
However, curing performance is also related to epoxy resin type, curing agent ratio, film thickness and ambient conditions.

Weak water and chemical resistance in coatings

Thanks to the hydrophobic side chain, CNSL derivatives can help support resistance to corrosion and chemical effects by reducing the water absorption of the coating.

Dependence on petroleum-based raw materials

Cashew Nut Shell Liquid is obtained as a by-product of the cashew processing industry and is a renewable phenol source that does not compete with the food chain. This property can allow part of phenol and alkylphenols to be replaced with bio-based content.
It should not be assumed that every CNSL product will show the same reactivity; the substitution ratio should be verified through laboratory trials.

POINTS TO CONSIDER WHEN USING CASHEW OIL

One of the most common mistakes in using Cashew Oil is assuming that all CNSL products have the same composition and can be used at the same ratio in every formulation. In fact, the compositional difference between Natural and Technical CNSL, the iodine value and the cardanol ratio are decisive in reaction behavior.

The following points should be considered when using Cashew Oil:

A CNSL grade suitable for the intended use should be selected.

A distinction should be made between Natural and Technical CNSL.

Iodine value and viscosity should be checked.

The cardanol, cardol and anacardic acid ratio should be examined.

Polymerization time should be monitored on a batch basis.

The aldehyde, amine or curing agent ratio should be determined through trials.

Catalyst type and amount should be evaluated.

Reaction temperature should be kept under control.

Moisture, ash and volatile matter content should be checked.

Dosage and formulation should be determined through laboratory trials.

Compatibility with other raw materials should be tested.

Manufacturer TDS and SDS documents should be reviewed.

Batch-based analysis results should be verified via the COA.

Cashew Oil is a substance requiring careful handling with regard to skin contact. Appropriate gloves, eye protection, work clothing and adequate ventilation should be used during transfer, weighing, mixing and reaction stages to prevent skin and eye contact. Safe working procedures should be determined according to the product's current SDS.
Exposure to vapors that may be released from heated or reacting CNSL, as well as to auxiliary raw materials such as aldehydes and amines, should also be evaluated separately.

STARTING FORMULATION APPROACHES FOR CASHEW OIL

The following examples are starting approaches prepared to show how Cashew Oil can be evaluated in the formulation development process. They are not validated commercial recipes, production instructions or regulation-compliant final formulas.
The ratios given are example starting levels for preliminary laboratory trials. The grade, iodine value and cardanol ratio of the CNSL used and other raw materials can significantly change performance. In every application, laboratory trials, performance tests, occupational safety and relevant regulatory checks should be carried out.

EXAMPLE 1: CNSL-BASED FRICTION DUST PRELIMINARY TRIAL

Objective: To obtain a friction dust usable in brake linings from Technical Cashew Nut Shell Oil and examine its quality parameters.

Starting approach:

Technical CNSL: 88–92%

Aldehyde source (e.g. hexamine): 8–12%

Catalyst: According to the CNSL grade and process method

The aldehyde source ratio should be adjusted according to the reactivity of the CNSL used and the targeted degree of hardening. For CNSL products with different iodine values, the ratios should be changed accordingly.

Application approach:

CNSL and the aldehyde source are weighed and mixed homogeneously.
The mixture is heated at a controlled temperature to achieve gelation.
The gelled mass is gradually fully cured at a higher temperature.
The cured material is cooled and broken up.
The material is ground and sieved to the desired particle size.
Acetone extract, ash content, thermal loss and particle size are measured.
The dust is used in a trial lining formulation, and friction and wear tests are performed.
Appropriate ventilation and extraction should be provided against vapors that may form during heating and curing stages.

EXAMPLE 2: CNSL-MODIFIED PHENOLIC RESIN RATIO SCREENING

Objective: To determine the effect of replacing part of the phenol in a phenolic resin with Cashew Nut Shell Liquid on flexibility and thermal resistance.

Starting components:

CNSL ratio used in place of phenol: 5%, 10%, 15% and 20%

Aldehyde ratio and catalyst: kept constant

Other process conditions: kept constant

The CNSL ratio is gradually increased and the changes in resin properties are compared.

Application approach:

Phenol and CNSL are charged to the reactor in the specified ratios.
Aldehyde and catalyst are added and the reaction is carried out at a controlled temperature.
Reaction progress is monitored by viscosity and free aldehyde measurements.
The resulting resins are cured under the same conditions.
Impact resistance, flexural strength and hardness are compared.
Thermal loss and water absorption are evaluated.
The ratio giving the most balanced result is determined.
It should not be assumed that a single CNSL ratio will give the same result in all phenolic resin systems.

EXAMPLE 3: EVALUATION AS A PROCESSING AID IN A RUBBER COMPOUND

Objective: To examine the effect of Cashew Nut Shell Oil on processability and vulcanization behavior in rubber compounds.

Starting approach:

Standard rubber compound formula: based on 100 phr rubber

Cashew Oil: 0, 2, 5 and 10 phr

Other components: kept constant

The evaluation can be done by partially or completely replacing the existing process oil or plasticizer with CNSL.

Application approach:

Compounds are prepared under the same mixing conditions.
Mooney viscosity is measured.
Vulcanization time and torque values are determined with a rheometer.
Samples are vulcanized under the same conditions.
Tensile strength, elongation at break and hardness are measured.
Property changes after aging are evaluated.
The appropriate usage ratio for production is determined.
In such evaluations, it should be taken into account that CNSL may affect the vulcanization system, and the accelerator balance should be readjusted if necessary.

SIMILAR PRODUCTS AND ALTERNATIVES TO CASHEW OIL

An alternative to Cashew Oil is not simply a matter of choosing another phenolic raw material. When determining an alternative, targeted reactivity, thermal resistance, flexibility, color, bio-based content, occupational safety requirements, regulations and final product performance should be evaluated together.

CASHEW OIL AND CARDANOL

Cardanol is the main component of Cashew Nut Shell Oil and is obtained as a purer product by vacuum distillation of technical CNSL. Therefore, when comparing CNSL and cardanol, two products of different purity from the same source are being evaluated.
Compared with technical CNSL, cardanol is lighter in color, lower in viscosity and has a more consistent composition. This property can provide advantages in applications such as epoxy curing agents, surfactants and light-colored coatings.
CNSL, on the other hand, is more economical and, because it contains cardol and polymeric material, is preferred in friction dust and some resin applications. When switching between the two products, reactivity and final product performance should be tested.

CASHEW OIL AND PHENOL

Petroleum-based phenol is the classic and most common raw material of phenolic resins. Cashew Nut Shell Oil is a bio-based alternative that can be used in place of part of the phenol in phenolic resins.
Resins produced with phenol offer high hardness and thermal resistance but can be brittle. CNSL, thanks to its long side chain, imparts flexibility and water resistance; however, at high ratios it can reduce thermal resistance and hardness.
For this reason, in most applications CNSL is evaluated not as a complete replacement for phenol but as a partial substitute at certain ratios.

CASHEW OIL AND ALKYLPHENOLS (NONYLPHENOL AND SIMILAR)

Synthetic alkylphenols such as nonylphenol and dodecylphenol are petroleum-based raw materials used in the production of resins, surfactants and additives. Cardanol and CNSL may show functional similarity to these products due to their long alkyl chain phenolic structures.
Regulatory restrictions on some alkylphenols have increased interest in bio-based cardanol derivatives. However, due to differences in chemical structure, reactivity and color, performance tests are required before direct substitution.

CASHEW OIL AND DRYING VEGETABLE OILS

Drying oils such as linseed oil and tung oil undergo oxidative polymerization thanks to their unsaturated structures and are used in coating and varnish applications.
Cashew Nut Shell Oil can also show similar drying behavior thanks to its high unsaturation; however, its ability to also react with aldehydes and amines due to its phenolic ring distinguishes it from drying oils.
Therefore, drying oils should not be considered direct alternatives to CNSL in applications requiring phenolic reactivity.

CASHEW OIL AND CONVENTIONAL EPOXY CURING AGENTS

Aliphatic amines, polyamides and amidoamines are curing agents commonly used in epoxy systems. Phenalkamines obtained from Cashew Nut Shell Oil stand out as alternatives to these products, especially under low-temperature and humid conditions.
Phenalkamines can offer fast curing and good water resistance; however, their color may be darker and their working time may differ from other curing agents.
Therefore, when changing the curing agent, the epoxy resin ratio, working time and final performance should be re-evaluated.

CASHEW OIL AND CASHEW KERNEL OIL

Although obtained from the same plant, Cashew Kernel Oil is a light-colored vegetable oil with a triglyceride structure, used for food and cosmetic purposes.
Since it does not have the phenolic reactivity of industrial Cashew Nut Shell Oil, it is not an alternative in resin, friction material or curing agent applications.
In selecting an alternative, targeted reactivity, thermal resistance, color, renewable content and cost should be determined through comparative laboratory tests.

QUALITY CONTROL AND PURCHASING CRITERIA FOR CASHEW OIL

When purchasing Cashew Oil, deciding only on the basis of product name and price is not sufficient. In particular, different forms such as Natural CNSL and Technical CNSL, as well as products of different origins, may have different technical properties.

Information recommended for review before purchasing:

Product name and manufacturer

CNSL form (Natural or Technical)

Whether it is shell oil or kernel oil

CAS number

EC / EINECS number

Cardanol, cardol and anacardic acid ratio

Iodine value

Viscosity

Density

Moisture content

Ash content

Volatile matter content

Polymerization time

Foreign matter content

Flash point

Technical data sheet (TDS)

Safety data sheet (SDS)

Certificate of analysis (COA)

Production and batch information

Origin information

Packaging type and net quantity

Storage conditions

Shelf life or retest information

REACH and related regulatory compliance information

The COA shows the analysis results of a specific batch of Cashew Oil. The TDS describes the product's general technical properties and recommended areas of use. The SDS contains information on safe use, transport, storage and emergencies.
These documents do not replace one another; they should be evaluated together.
Especially when purchasing CNSL, the supplier should be asked whether the product is Natural CNSL or Technical CNSL, as well as its iodine value, viscosity and polymerization time. This is because products with different reactivity and processing behavior may be found under the same Cashew Nut Shell Liquid name.

STORAGE AND TRANSPORT OF CASHEW OIL

Cashew Oil should be stored under the conditions recommended by the manufacturer, in a cool, dry and well-ventilated area, in its tightly closed original packaging.
The product should not be exposed to high temperatures, direct sunlight, moisture or heat sources. Prolonged exposure to heat and air can lead to an increase in viscosity and partial polymerization due to the double bonds in the side chain.
Cashew Nut Shell Oil should be stored separately from strong oxidizing agents, strong acids and bases, and materials that may react with it, such as aldehydes and amines.
Once the packaging is opened, it is important to protect the product from moisture, air and contamination. Clean and dry equipment should be used during handling, and the packaging should be properly resealed.
Controlled heating may be applied for the transfer of the product, whose viscosity may increase in cold weather; however, excessive and prolonged heating should be avoided. In case of spillage, the cleanup procedures specified in the SDS should be followed.
Products that have been stored for a long time or whose viscosity has changed noticeably should be evaluated in line with the manufacturer's specifications.

CASHEW OIL SAFETY INFORMATION

The safe use of Cashew Oil depends on the current SDS of the supplied product and the implementation of appropriate occupational safety measures.
Due to the phenolic components it contains, such as anacardic acid, cardol and cardanol, Cashew Nut Shell Oil may be irritating to the skin and eyes and may cause skin sensitization (allergic reaction). Supplier SDSs may include classifications such as skin irritation, serious eye damage or eye irritation, skin sensitization and harmful effects to the aquatic environment. Current hazard and precautionary statements should be checked in the supplier's SDS.
Cashew Nut Shell Liquid is a substance registered under the European Union REACH Regulation. Applicable obligations for companies using and placing the product on the market, and the current regulatory status, should be followed through the relevant official sources.
In particular, skin contact with the product should be prevented. Chemical-resistant protective gloves, eye protection, work clothing and appropriate ventilation should be used during transfer, weighing, mixing and reaction operations. Local exhaust ventilation should be provided against vapor formation in heated products.
Contaminated clothing should be washed before reuse; in case of skin contact, the area should be cleaned with plenty of soap and water, and medical attention should be sought if necessary.
In cured resin, friction dust or coatings, CNSL components are bound to the polymer network. Safety measures are particularly important during pre-cure stages such as raw material handling, resin production and friction dust production.
It should not be assumed that safety information for different manufacturers or different CNSL forms is the same. The current SDS and the manufacturer's technical document should be taken as the basis.

WHAT SHOULD BE CONSIDERED WHEN PURCHASING CASHEW OIL?

The first step in sourcing Cashew Oil is to clarify for what purpose and in which system the product will be used. The quality criteria sought for friction dust, modified phenolic resin, epoxy curing agent, coating or rubber applications may not be the same.
Therefore, rather than writing only "Cashew Oil" or "CNSL" in the purchase request, specifying the field of use, whether shell oil or kernel oil is required, and the targeted technical performance enables a more accurate product evaluation.

The following information should be clarified before purchasing:

Sector of use and final application

Required product: Cashew Nut Shell Oil (CNSL) or Cashew Kernel Oil

Natural CNSL or Technical CNSL requirement

Required iodine value range

Required viscosity range

Cardanol ratio requirements

Polymerization time requirements

Moisture, ash and volatile matter limits

Required quality standard

Manufacturer and origin information requirement

Required packaging type and quantity

TDS, SDS and COA needs

REACH and other regulatory compliance documents

If replacing an existing product, the technical properties of the existing product

The price of Cashew Oil may vary depending on product form, cardanol ratio, iodine value, viscosity, origin, harvest period and raw cashew supply, order quantity, packaging, logistics and current market conditions. Therefore, the current CNSL price should be evaluated through a quotation together with the product specification and delivery terms.

CASHEW OIL SUPPLY FROM ATAMAN KIMYA

Cashew Oil is an important natural raw material evaluated for various technical functions such as bio-based phenol source, imparting flexibility, thermal stability and water resistance in friction materials, phenolic resins, epoxy curing agents, coatings and rubber applications. It is important for manufacturers planning to purchase the product to clarify the CNSL form, technical properties, quality grade and required documents suitable for their field of use before ordering.
Companies wishing to obtain information about Cashew Oil supply from Ataman Kimya can share their fields of use and technical needs and request information on product suitability, current supply status, packaging options and price quotations.
The product's current stock status, origin, CNSL form, technical properties, packaging and specifications should be confirmed with Ataman Kimya before ordering.

Sharing the following information in a quotation request makes it easier to evaluate the right Cashew Oil product:

Sector of use and final application

Requested product type (shell oil or kernel oil)

Requested CNSL form

Requested iodine value and viscosity

Resin or process information used

Requested quality standard

Estimated order quantity

Required packaging type

Requested technical documents

TDS or COA information of the existing product, if any

FREQUENTLY ASKED QUESTIONS ABOUT CASHEW OIL

What is Cashew Oil?
In industrial chemistry, Cashew Oil is a dark-colored natural liquid obtained from the shell of the cashew nut, consisting of phenolic lipids such as cardanol, cardol and anacardic acid. It is called Cashew Nut Shell Oil or CNSL for short and is used especially in friction materials and in phenolic and epoxy resins.

What does CNSL stand for?
CNSL is the abbreviation of Cashew Nut Shell Liquid. In Turkish it is also referred to as Kaju Kabuğu Yağı or Kaju Kabuk Sıvısı.

What is the CAS number of Cashew Oil?
The CAS number for Cashew Nut Shell Oil (Cashew Nut Shell Liquid) is 8007-24-7.

What is the EC / EINECS number of Cashew Oil?
The EC / EINECS number for Cashew Nut Shell Liquid is listed as 232-355-4.

What is the chemical formula of Cashew Oil?
Since Cashew Oil is a natural mixture, it does not have a single chemical formula. The formula of the main component cardanol varies between C₂₁H₃₀O and C₂₁H₃₆O depending on the number of double bonds in the side chain.

Are Cashew Nut Shell Oil and Cashew Kernel Oil the same product?
No. Cashew Nut Shell Oil is a phenolic, dark-colored product intended for industrial use. Cashew Kernel Oil is a light-colored vegetable oil with a triglyceride structure used in food and cosmetics.

What is the difference between Natural CNSL and Technical CNSL?
Natural CNSL is obtained by cold methods and is rich in anacardic acid. Technical CNSL is obtained by the hot method; since anacardic acid is converted into cardanol under the effect of heat, it is rich in cardanol.

What is Cashew Oil used for?
Cashew Oil is used as a bio-based phenol source in friction dust production, modification of phenolic resins, production of phenalkamine epoxy curing agents, coatings, rubber compounds and the production of various derivative chemicals.

In which sectors is Cashew Oil used?
Cashew Nut Shell Oil can be used in the automotive friction materials, resin, paint and coating, rubber, laminate and composite, foundry, adhesive and surfactant sectors.

How does Cashew Oil work in brake linings?
CNSL is polymerized into friction dust. This dust, as an organic component in the lining, helps keep the friction coefficient stable, reduce noise and limit heat-related performance loss.

What is cardanol?
Cardanol is a phenol with a long side chain that is the main component of Cashew Nut Shell Oil. It is obtained in purer form by distillation of technical CNSL and is used in epoxy curing agents, surfactants and resins.

What is phenalkamine?
Phenalkamine is an epoxy curing agent obtained by subjecting cardanol to a Mannich reaction with formaldehyde and an amine. It is known for its ability to cure at low temperatures and in humid environments.

Can Cashew Oil be used instead of phenol?
CNSL can be used in place of part of the phenol in phenolic resins. However, since complete substitution generally changes thermal resistance and hardness, the ratio should be determined through laboratory trials.

Is Cashew Oil a bio-based raw material?
Yes. Cashew Nut Shell Oil is a raw material of renewable origin obtained as a by-product of the cashew processing industry, and it does not compete with the food chain.

Is Cashew Oil used in cosmetics or food?
Industrial Cashew Nut Shell Oil should not be used for cosmetic, food or pharmaceutical purposes. The product used in these fields is Cashew Kernel Oil, known as Anacardium Occidentale (Cashew) Seed Oil.

Is Cashew Oil a hazardous substance?
Cashew Nut Shell Oil may be irritating to the skin and eyes and may cause skin sensitization. Therefore, appropriate protective equipment should be used during handling and the current SDS should be taken as the basis.

Is Cashew Oil registered under REACH?
Cashew Nut Shell Liquid is a substance registered under REACH. The current regulatory status and related obligations should be followed through official sources.

Are cured CNSL-based products safe?
After curing, CNSL components are chemically bound to the polymer network. Safety measures are particularly important during raw material handling and resin or friction dust production stages. For special areas of use, the compliance of the final product with the relevant regulations should be evaluated separately.

Is Cashew Oil soluble in water?
No. Cashew Nut Shell Oil is practically insoluble in water; it is miscible with alcohols, ketones and hydrocarbon solvents.

What is the physical appearance of Cashew Oil?
Cashew Oil is generally a dark brown to black, viscous liquid with a characteristic odor.

Why is the iodine value of Cashew Oil important?
The iodine value is an indicator of unsaturation in the side chain and directly affects the product's polymerization, drying and resin-forming behavior. The current value should be checked in the supplier's TDS and COA documents.

What does the price of Cashew Oil depend on?
CNSL price may vary depending on product form, cardanol ratio, iodine value, viscosity, origin, raw cashew supply, packaging, order quantity, logistics and market conditions.

Are there alternatives to Cashew Oil?
Cardanol, petroleum-based phenol, synthetic alkylphenols, drying vegetable oils and conventional epoxy curing agents can be evaluated as alternatives in certain applications. However, the choice of alternative should be made according to the targeted performance and system.

How should Cashew Oil be stored?
Cashew Oil should be stored in a cool, dry and well-ventilated area, in its tightly closed original packaging, away from heat sources, oxidizers and reactive substances.

Which documents should be requested when purchasing Cashew Oil?
TDS, SDS and COA are the basic documents. In addition, origin information, REACH and related regulatory compliance information can be requested.

Which technical properties are important when purchasing Cashew Oil?
CNSL form, cardanol ratio, iodine value, viscosity, density, moisture, ash, volatile matter, polymerization time and foreign matter content may be important depending on the intended use.

CASHEW OIL – TECHNICAL SUMMARY

Cashew Oil, known in Turkish as Kaju Kabuğu Yağı and CNSL for short, is a dark-colored, viscous natural raw material obtained from the shell of the cashew nut, consisting of long side-chain phenolic lipids such as cardanol, cardol and anacardic acid. It may be searched for under different names such as Cashew Nut Shell Liquid, Cashew Nut Shell Oil, Cashew Shell Liquid and Technical CNSL.
Cashew Oil is not a single commercial product type. Although Natural CNSL and Technical CNSL are obtained from the same source, their component distribution, reactivity and processing behavior are different. Iodine value, viscosity, cardanol ratio and polymerization time are also important parameters affecting performance.
CAS No 8007-24-7 and EC No 232-355-4 are used for Cashew Nut Shell Oil. Since the term "Cashew Oil" can also be used for Cashew Kernel Oil intended for food and cosmetics, the full definition and form of the product should be checked at the time of purchase.
Cashew Oil is mainly used as a bio-based phenol source in friction materials, modified phenolic resins, phenalkamine epoxy curing agents, coatings and rubber compounds. It helps provide flexibility, thermal stability, water and chemical resistance and friction stability. Performance depends on the CNSL grade, usage ratio, auxiliary raw materials and process conditions.
Since Cashew Nut Shell Oil has the potential for skin and eye irritation and skin sensitization, appropriate occupational safety measures must be taken during processing and the current SDS must be taken as the basis. Selecting the right form of CNSL, which can be evaluated in automotive, resin, coating, rubber and composite applications, is important for final product performance.
Companies planning to source Cashew Oil from Ataman Kimya are advised to share their field of use, requested product type and CNSL form, iodine value, viscosity, quality standard, quantity and technical document needs to confirm current product, stock, origin, packaging and quotation information.