Linseed oil, also known as flaxseed oil or flax oil, is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (Linum usitatissimum). 

The oil is obtained by pressing, sometimes followed by solvent extraction.

Owing to its polymer-forming properties, linseed oil is often blended with combinations of other oils, resins or solvents as an impregnator, drying oil finish or varnish in wood finishing, as a pigment binder in oil paints, as a plasticizer and hardener in putty, and in the manufacture of linoleum. 

Linseed oil use has declined over the past several decades with increased availability of synthetic alkyd resins—which function similarly but resist yellowing.[1]

Linseed oil is an edible oil in demand as a dietary supplement, as a source of α-Linolenic acid, an omega-3 fatty acid. 

In parts of Europe, it is traditionally eaten with potatoes and quark.

Linseed Oil, also known as flaxseed oil is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (Linum usitatissimum, Linaceae). The oil is obtained by pressing, sometimes followed by solvent extraction. Flax-based oils are sought after as food because of their high levels of α-Linolenic acid (a particular form of omega-3 fatty acid), but it is important that only food-grade oil be used for food.

Linseed oil is commonly utilized in paint, wood finish, putty, food processing, nutritional supplements, and numerous other uses

Substance name:linseed oil

Trade name:Linseed oil Refined

EC / List no.: 232-278-6

CAS no.: 8001-26-1

HS code:15151910

Linseed oil is a useful ingredient presented in dairy products, baked goods, muffins, dried noodles, and processed meats. 

Moreover, Linseed oil can be exchanged for other types of oil in flavoring agents, dips, margarine, and sauces. 

Linseed oil can also be applied directly to the skin to boost its health by rising its moisture content

Linseed oil's polymer-forming property to polymerize into solid form, largely utilized for blending with several solvents and resins as impregnator and linoleum in the paints & coatings sector

Linseed oil is also utilized in the manufacturing process of other oils, having properties like bonding, grinding, tempering, and catalyzed curing.

Linseed oil is the most widely used natural drying oil and is the main ingredient in printing inks and paint vehicles.

Linseed oil, obtained from flaxseed, is one of the most precious oils found in nature. 

Linseed oil is used as a wood and concrete preservative, as well as a component of varnishes, paints, and dyes.

Linseed oil comes with preventive qualities, i.e., preventing deterioration of concrete and wood surfaces and thus safeguarding the longevity and quality of products coated with the oil

Linseed oil also finds its application in oil paints, soaps, inks, and linoleum as a carrier for making them glossy and transparent and enhancing their consistency.

Structure and composition

Linseed oil is a triglyceride, like other fats. Linseed oil is distinctive for its unusually large amount of α-linolenic acid, which oxidises in air. 

The fatty acids in a typical linseed oil are of the following types:

The triply unsaturated α-linolenic acid (51.9–55.2%),

The saturated acids palmitic acid (about 7%) and stearic acid (3.4–4.6%),

The monounsaturated oleic acid (18.5–22.6%),

The doubly unsaturated linoleic acid (14.2–17%).

Linseed oil is predicted to grow in demand due to its widening application scope as an additive used in oil paints to impart features such as finishing, making it liquid, clear, and glossy.

Linseed oil is used as a carrier in oil paints for making them glossy, transparent, and improve their consistency. 

Linseed oil is also used in inks, soaps, and linoleum. 

Linseed oil has preservative qualities, which prevent the deterioration of concrete and wood surfaces ensuring the longevity and quality of products coated with the oil. 

Increasing demand for wood finishing is projected to propel linseed oil market growth.

Applications

Market by Application

Paints & Varnishes

Paint

Lacquers

Wood Protection

Food Processing

Animal Nutrition & Care

Cosmetics

Pharmaceuticals

Others

Most applications of linseed oil exploit its drying properties, i.e., the initial material is liquid or at least pliable and the aged material is rigid but not brittle. 

The water-repelling (hydrophobic) nature of the resulting hydrocarbon-based material is advantageous.

Paint binder

Linseed oil is the carrier used in oil paint. 

Linseed oil can also be used as a painting medium, making oil paints more fluid, transparent and glossy. 

Linseed oil is available in varieties such as cold-pressed, alkali-refined, sun-bleached, sun-thickened, and polymerised (stand oil). 

The introduction of linseed oil was a significant advance in the technology of oil painting.

Putty

Traditional glazing putty, consisting of a paste of chalk powder and linseed oil, is a sealant for glass windows that hardens within a few weeks of application and can then be painted over. 

The durability of putty is owed to the drying properties of linseed oil.

Wood finish

When used as a wood finish, linseed oil dries slowly and shrinks little upon hardening. 

A linseed oil finish is easily scratched and liquid water penetrates a linseed oil finish in mere minutes, and water vapour bypasses it almost completely.

Garden furniture treated with linseed oil may develop mildew. 

Oiled wood may be yellowish and is likely to darken with age. 

Even though the oil feels dry to the touch, studies show linseed oil does not fully cure.

Linseed oil is a common finish for wooden items, though very fine finish may require months to obtain. 

Studies show the fatty-acid structure of linseed oil has problems cross-linking and oxidizing, frequently turning black.

It is no longer encouraged to use linseed oil to recondition and regenerate finishes because of the cross-linking oxidization that occurs.

Gilding

Boiled linseed oil is used as sizing in traditional oil gilding to adhere sheets of gold leaf to a substrate (parchment, canvas, Armenian bole, etc.). 

It has a much longer working time than water-based size and gives a firm smooth surface that is adhesive enough in the first 12–24 hours after application to cause the gold to attach firmly to the intended surface.

Linoleum

Linseed oil is used to bind wood dust, cork particles, and related materials in the manufacture of the floor covering linoleum. 

After its invention in 1860 by Frederick Walton, linoleum, or 'lino' for short, was a common form of domestic and industrial floor covering from the 1870s until the 1970s when it was largely replaced by PVC ('vinyl') floor coverings.

However, since the 1990s, linoleum is returning to favor, being considered more environmentally sound than PVC.

Linoleum has given its name to the printmaking technique linocut, in which a relief design is cut into the smooth surface and then inked and used to print an image. 

The results are similar to those obtained by woodcut printing.

Nutritional supplement and food

Raw cold-pressed linseed oil – commonly known as flax seed oil in nutritional contexts – is easily oxidized, and rapidly becomes rancid, with an unpleasant odour, unless refrigerated. 

Linseed oil is not generally recommended for use in cooking. 

In one study, the content of Alpha linolenic acid (ALA) in whole flaxseeds did not decrease after heating the seeds to temperatures of up to 178 °C (352.4 °F) for one and a half hours.

Food-grade flaxseed oil is cold-pressed, obtained without solvent extraction, in the absence of oxygen, and marketed as edible flaxseed oil. 

Fresh, refrigerated and unprocessed, linseed oil is used as a nutritional supplement and is a traditional European ethnic food, highly regarded for its nutty flavor. 

Regular flaxseed oil contains between 57% and 71% polyunsaturated fats (alpha-linolenic acid, linoleic acid).

Plant breeders have developed flaxseed with both higher ALA (70%) and very low ALA content (< 3%).

The USFDA granted generally recognized as safe (GRAS) status for high alpha linolenic flaxseed oil.

Modified linseed oils

Stand oil

Stand oil is generated by heating linseed oil near 300 °C for a few days in the complete absence of air. 

Under these conditions, the polyunsaturated fatty esters convert to conjugated dienes, which then undergo Diels-Alder reactions, leading to crosslinking. 

The product, which is highly viscous, gives highly uniform coatings that "dry" to more elastic coatings than linseed oil itself. 

Soybean oil can be treated similarly, but converts more slowly. 

On the other hand, tung oil converts very quickly, being complete in minutes at 260 °C. 

Coatings prepared from stand oils are less prone to yellowing than are coatings derived from the parent oils.

Boiled linseed oil

Boiled linseed oil is a combination of raw linseed oil, stand oil (see above), and metallic oil drying agents (catalysts to accelerate drying).

In the Medieval era, linseed oil was boiled with lead oxide (litharge) to give a product called boiled linseed oil.

The lead oxide forms lead "soaps" (lead oxide is alkaline) which promotes hardening (polymerisation) of linseed oil by reaction with atmospheric oxygen. 

Heating shortens its drying time.

Raw linseed oil

Raw linseed oil is the base oil, unprocessed and without driers or thinners.

It is mostly used as a feedstock for making a boiled oil. 

It does not cure sufficiently well or quickly to be regarded as a drying oil.

Raw linseed is sometimes used for oiling cricket bats to increase surface friction for better ball control.

It was also used to treat leather flat belt drives to reduce slipping.

Translated names

Aceite de linaza (es)

Huile de lin (fr)

Laneno olje (sl)

Laneno ulje (hr)

Leinsamenöl (de)

Lenmagolaj (hu)

Lijnolie (nl)

Linaseemneõli (et)

Linolie (da)

Linolja (sv)

Linseed oil (no)

Linsēklu eļļa (lv)

Lněný olej (cs)

Olej lniany (pl)

Olio di lino (it)

Pellavansiemenöljy (fi)

Sėmenų aliejus (lt)

Ulei de in (ro)

Óleo de linhaça (pt)

Ľanový olej (sk)

Żejt tal-kittien (mt)

Λινέλαιο (el)

Масло от ленено семе (bg)