Wax emulsion

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A wax emulsion is a stable mixture of one or more waxes in water. Waxes and water are normally immiscible but can be brought together stably by the use of surfactants and a clever preparation process. Strictly speaking a wax emulsion should be called a wax dispersion since the wax is solid at room temperature. However, because the preparation takes place above the melting point of the wax, the actual process is called emulsification, hence the name wax emulsion. In praxis, wax dispersion is used for solvent based systems.

In chemistry, a mixture is a material made up of two or more different substances which are mixed. A mixture refers to the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.

Wax class of chemical compounds that are plastic (malleable) near ambient temperatures.

Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to give low viscosity liquids. Waxes are insoluble in water but soluble in organic, nonpolar solvents. Natural waxes of different types are produced by plants and animals and occur in petroleum.

Water chemical compound

Water is a transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.

A wide range of emulsions based on different waxes and blends thereof are available, depending on the final application. Waxes that are found in wax emulsions can be of natural or synthetic origin. Common non-fossil natural waxes are carnaubawax, beeswax, candelilla wax or ricebran wax. Paraffin, microcrystalline and montanwax are the most used fossil natural waxes that are found in emulsions. Synthetic waxes that are used include (oxidised) LDPE and HDPE, maelic grafted PP and Fischer-Tropsch waxes.

A range of different emulsifiers or surfactants are used to emulsify waxes. These can be anionic, cationic or non-ionic in nature. The most common however are fatty alcohol ethoxylates as non-ionic surfactants due to their superb stability against hard water, pH-shock and electrolytes. Some applications demand different emulsifier systems for example anionic surfactants for better hydrophobicity or cationic surfactants for better adhesion to certain materials like textile fibers.

Applications

Wax emulsions are widely used in a variety of technical applications like printing inks & lacquers, leather and textiles, paper, wood, metal, polishes, glass fiber sizing, glass bottle protection among other things. The most important properties that can be improved by the addition of wax emulsions are matting & gloss, hydrophobicity, soft touch, abrasion & rub resistance, scratch resistance, release, corrosion protection and anti-blocking. [1]

Emulsions based on natural waxes are used for coating fruits and candies and crop protection. Synthetic wax based emulsions are often used in food packaging.

Wax emulsions based on beeswax, carnauba wax and paraffin wax are used in creams and ointments.

The emergence of soybean waxes with varying properties and melt points has led to the use of vegetable wax emulsions in applications such as paper coatings, paint and ink additives, and even wet sizing for pulp and paper applications. These wax emulsions can be formulated to deliver some of the same properties that petroleum-based wax emulsions deliver, but offer advantages of being a green product and offer more consistent availability. [2]

Related Research Articles

An emulsion is a mixture of two or more liquids that are normally immiscible. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, and some cutting fluids for metal working.

Paraffin wax chemical compound

Paraffin wax is a soft colourless solid, derived from petroleum, coal or shale oil, that consists of a mixture of hydrocarbon molecules containing between twenty and forty carbon atoms. It is solid at room temperature and begins to melt above approximately 37 °C (99 °F); its boiling point is >370 °C (698 °F). Common applications for paraffin wax include lubrication, electrical insulation, and candles; dyed paraffin wax can be made into crayons. It is distinct from kerosene and other petroleum products that are sometimes called paraffin.

Surfactant Substance that lowers the surface tension between a liquid and another material

Surfactants are compounds that lower the surface tension between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.

Emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomer, and surfactant. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer are emulsified in a continuous phase of water. Water-soluble polymers, such as certain polyvinyl alcohols or hydroxyethyl celluloses, can also be used to act as emulsifiers/stabilizers. The name "emulsion polymerization" is a misnomer that arises from a historical misconception. Rather than occurring in emulsion droplets, polymerization takes place in the latex/colloid particles that form spontaneously in the first few minutes of the process. These latex particles are typically 100 nm in size, and are made of many individual polymer chains. The particles are prevented from coagulating with each other because each particle is surrounded by the surfactant ('soap'); the charge on the surfactant repels other particles electrostatically. When water-soluble polymers are used as stabilizers instead of soap, the repulsion between particles arises because these water-soluble polymers form a 'hairy layer' around a particle that repels other particles, because pushing particles together would involve compressing these chains.

Micelle group of molecules

A micelle or micella is an aggregate of surfactant molecules dispersed in a liquid colloid. A typical micelle in aqueous solution forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tail lipids in a bilayer. The difficulty filling all the volume of the interior of a bilayer, while accommodating the area per head group forced on the molecule by the hydration of the lipid head group, leads to the formation of the micelle. This type of micelle is known as a normal-phase micelle. Inverse micelles have the head groups at the centre with the tails extending out. Micelles are approximately spherical in shape. Other phases, including shapes such as ellipsoids, cylinders, and bilayers, are also possible. The shape and size of a micelle are a function of the molecular geometry of its surfactant molecules and solution conditions such as surfactant concentration, temperature, pH, and ionic strength. The process of forming micelles is known as micellisation and forms part of the phase behaviour of many lipids according to their polymorphism.

Lipophilicity, refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves lipophilic, and the axiom that "like dissolves like" generally holds true. Thus lipophilic substances tend to dissolve in other lipophilic substances, but hydrophilic ("water-loving") substances tend to dissolve in water and other hydrophilic substances.

Polyelectrolyte

Polyelectrolytes are polymers whose repeating units bear an electrolyte group. Polycations and polyanions are polyelectrolytes. These groups dissociate in aqueous solutions (water), making the polymers charged. Polyelectrolyte properties are thus similar to both electrolytes (salts) and polymers and are sometimes called polysalts. Like salts, their solutions are electrically conductive. Like polymers, their solutions are often viscous. Charged molecular chains, commonly present in soft matter systems, play a fundamental role in determining structure, stability and the interactions of various molecular assemblies. Theoretical approaches to describing their statistical properties differ profoundly from those of their electrically neutral counterparts, while technological and industrial fields exploit their unique properties. Many biological molecules are polyelectrolytes. For instance, polypeptides, glycosaminoglycans, and DNA are polyelectrolytes. Both natural and synthetic polyelectrolytes are used in a variety of industries.

A fabric softener is a conditioner that is typically applied to laundry during the rinse cycle in a washing machine. In contrast to laundry detergents, fabric softeners may be regarded as a kind of after-treatment laundry aid.

Laundry detergent

Laundry detergent, or washing powder, is a type of detergent that is added for cleaning laundry. While detergent is still sold in powdered form, liquid detergents have been taking major market shares in many countries since their introduction in the 1950s.

Sorbitan monostearate is an ester of sorbitan and stearic acid and is sometimes referred to as a synthetic wax.

Finishing (textiles) any process performed after dyeing the yarn or fabric to improve the look, performance, or "hand" (feel) of the finished textile or clothing

In textile manufacturing, finishing refers to the processes that convert the woven or knitted cloth into a usable material and more specifically to any process performed after dyeing the yarn or fabric to improve the look, performance, or "hand" (feel) of the finish textile or clothing. The precise meaning depends on context.

Defoamer Chemical additive that reduces and hinders the formation of foam in liquids

A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably. Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.

Paper chemicals

Paper chemicals designate a group of chemicals that are used for paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and brightness, or by increasing its strength and resistance to water.

Paint has four major components: pigments, binders, solvents, and additives. Pigments serve to give paint its color, texture, toughness, as well as determining if a paint is opaque or not. Common white pigments include titanium dioxide and zinc oxide. Binders are the film forming component of a paint as it dries and affects the durability, gloss, and flexibility of the coating. Polyurethanes, polyesters, and acrylics are all examples of common binders. The solvent is the medium in which all other components of the paint are dissolved and evaporates away as the paint dries and cures. The solvent also modifies the curing rate and viscosity of the paint in its liquid state. There are two types of paint: solvent-borne and water-borne paints. Solvent-borne paints use organic solvents as the primary vehicle carrying the solid components in a paint formulation, whereas water-borne paints use water as the continuous medium. The additives that are incorporated into paints are a wide range of things which impart important effects on the properties of the paint and the final coating. Common paint additives are catalysts, thickeners, stabilizers, emulsifiers, texturizers, biocides to fight bacterial growth, etc.

Adsorption of polyelectrolytes on solid substrates is a surface phenomenon where long-chained polymer molecules with charged groups bind to a surface that is charged in the opposite polarity. On the molecular level, the polymers do not actually bond to the surface, but tend to "stick" to the surface via intermolecular forces and the charges created by the dissociation of various side groups of the polymer. Because the polymer molecules are so long, they have a large amount of surface area with which to contact the surface and thus do not desorb as small molecules are likely to do. This means that adsorbed layers of polyelectrolytes form a very durable coating. Due to this important characteristic of polyelectrolyte layers they are used extensively in industry as flocculants, for solubilization, as supersorbers, antistatic agents, as oil recovery aids, as gelling aids in nutrition, additives in concrete, or for blood compatibility enhancement to name a few.

Polyelectrolytes are charged polymers capable of stabilizing colloidal emulsions through electrostatic interactions. Their effectiveness can be dependent on molecular weight, pH, solvent polarity, ionic strength, and the hydrophilic-lipophilic balance (HLB). Stabilized emulsions are useful in many industrial processes, including deflocculation, drug delivery, petroleum waste treatment, and food technology.

The surface chemistry of paper is responsible for many important paper properties, such as gloss, waterproofing, and printability. Many components are used in the paper-making process that affect the surface.

Alkyl ketene dimer

Alkyl ketene dimers (AKDs) are a family of organic compounds based on the 4-membered ring system of 2-oxetanone, which is also the central structural element of propiolactone and diketene. Attached to the oxetane ring of technically relevant alkyl ketene dimers there is a C12 – C16 alkyl group in the 3-position and a C13 – C17 alkylidene group in the 4-position.

Polyurethane Dispersion, or PUD, is understood to be a polyurethane polymer resin dispersed in water, rather than a solvent. Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG incorporated into, or pendant from, the polymer backbone.

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