WAX EMULSIONS
WAX EMULSIONS
ATAMAN offers a full range of WAX EMULSIONS for food contact and technical applications and are based on a variety of waxes like LDPE, HDPE, primary PE, Maleic grafted PP, Paraffin, Bees, Carnauba and blends thereof.
Our wax emulsions are used in a huge number of applications of which the following are most common:
Coating, paint- and ink industry
Anti blocking properties
Anti-graffiti
Gloss improvement
Improvement of rub and scratch resistance
Slip modification
Metal
Corrosion protection
Lubricity (deep-drawing)
Release agents
Paper
Barrier for water, moisture and grease
Heat sealability
Release and anti blocking properties
Surface gloss
Polishes
Car polishes
Floor maintenance
Self shine emulsions
Slip reduction
Textile and Leather
Gloss improvement
Softener
Sewability improvement
Water repellency
Wood, chip- and fiberboard
Hydrophobing
Waxed woods
Release
What is WAX EMULSION ?
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.
Wax emulsions and dispersions are formulated additives made of fine and stabilized wax particles, homogeneously distributed in water.
Being in the liquid form, they are easily incorporated into coatings and inks formulations by simple mixing.
Wax emulsions normally have particle size < 1µm, and therefore, a minimized effect on the coating gloss
Wax dispersions (either water or solvent-based), have a particle size typically > 1-2µm
Their very fine particle size ensures thorough, homogeneous incorporation with other ingredients of the formulation, maximizing the required effects.
Wax emulsions can be stabilized by either non-ionic emulsifiers (steric mechanism) or by ionic emulsifiers, most often anionic (electrostatic mechanism). Combining anionic and non-ionic emulsifiers provides the emulsion the optimum stability because wax particles are protected through both stabilization mechanisms.
In addition, each stabilization mechanism not only has its own advantages and limitations but also significantly impacts the overall formulation giving added flexibility in formulating.
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, maleic anhydride grafted polypropylene 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.
Wax emulsion based products are widely utilized in formulation of paints, printing inks, textiles, and floor polishes.
Automotive coatings, metal working, packaging films, and anti-transpiration products as well as wood and timber protection.
They are employed in sectors such as agriculture also.
In printing inks wax emulsions are used to impart anti-scuff properties and more importantly, anti-blocking properties.
Polyethylene wax emulsions are used in the textile industry on both natural and synthetic fibers.
Wax emulsions are widely used in interior wood finishes as well as for the outdoor timber treatment.
Interior wood finishes are enhanced by the addition of a wax emulsion.
Polyethylene wax emulsions are an ideal additive for water-based coatings due to their physical stability, small particle size and ease of handling.
Oxidized polyethylene waxes is an essential component of liquid floor polishes.
Addition of wax imparts properties such as water resistance, gloss, durability, black heel mark resistance, and self-healing.
Applications
Waxes have a significant impact on several formulations and processes.
It offers lubrication along with abrasion resistance, anti-blocking, matting, and water repellency properties to the resulting product.
This leads to its wide applications in paints & coatings, adhesives & sealants, cosmetics, textiles, and others.
The sources of waxes can be natural or synthetic, natural waxes includes beeswax (animal-based) and carnauba (vegetable based); and artificial waxes include paraffin wax, amide wax, polyethylene wax, polypropylene wax, and montan wax, among others.
Extensive use of wax emulsion in paints and coatings for enhanced properties such as matting & gloss, hydrophobicity, soft-touch, abrasion & rub resistance augments the market growth
Adding emulsifier to polyethylene wax to make pe wax emulsion, adding it to acrylic resin, it can improve its hydrophilicity to some extent, and it can play the role of anti-slip, anti-blocking and stain resistance.
Adhesion refers to the mutual contact between adhesion of the surface of the paint film to foreign substances and the paint films forms adhesion, and then adhesion is exposed to the atmosphere by ash, staining and pressure to bond.
In the coating film, an auxiliary polyethylene wax is added. Its function is that it gradually migrates from the state of uniform dispersion within the film to the surface of the film.
Due to this migration, the surface of the film can be made to have an anti-blocking effect.
Polyethylene wax also produces synergistic effects such as abrasion and scratch resistance.
It can reduce the friction coefficient of the surface of the coating, so that the sliding tendency of the object when it contacts the surface of the coating is greater than the tendency of scratching. The migration of the polyethylene wax powder to the surface of the coating film can greatly reduce the dynamic friction coefficient of the surface of the coating film. The addition of the polyethylene wax micropowder to the coating allows the coating film to greatly reduce the tendency to be polished by friction, thereby maintaining low gloss durability. Polyethylene wax has obvious extinction characteristics for polyester coatings, generally added in an amount of about 1%; in addition, pe wax emulsion has a certain influence on the molten horizontal fluidity of powder coatings, and can be used as a modifier.
Improving the brightness of the paint is relative with HDPE wax emulsion, but not the most important substance.
The core important thing is the film-forming substance (whether it is a high-gloss resin emulsion or not).
The water-based wax emulsion reacts with the film-forming substance to form a hardness on the surface of the paint film. Wear-resistant, good transparency, scratch-resistant, anti-friction, good gloss, good feel.
Why water-based wax emulsion is used to increase the brightness of paint?
First, the water-based wax emulsion in the coating / ink does not contain any volatile substances. It is green, environmentally friendly, and high hardness, good wear resistance, good transparency, scratch resistance, friction resistance. The water-based wax emulsion not only has the effect of improving gloss, but also a matte effect.
Second, which factors will affect the effect of water-based wax paste to improve gloss?
This is related to the particle size of the aqueous wax emulsion. The smaller the particle size, the higher the gloss.
Applying the wax emulsion to the preparation system of the waterborne wood coating can greatly improve the anti-back tack and scratch resistance of the paint film.
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.
Waxes are frequently used as additives in coating formulations. Our range of Polyethylene waxes can be used in a number of coating types, particularly in:
Powder coatings
Can Coatings
Coil Coatings
Wood/furniture coatings
PROPERTIES OBTAINABLE FROM WAX AND WAX EMULSIONS
1) Abrasion, rub and mar resistance
Waxes are used to protect a coating and/or its substrate from cosmetic and physical damage.
The hardness of the wax will determine the effectiveness in improving abrasion resistance.
The wax in an exterior topcoat for beverage cans must help protect the decorative aspect of the container, i.e. the ink.
Additionally, the use of wax in the coating formulation prevents physical damage to the topcoat caused by contact with another can.
2) Coefficient of friction
Many applications require the coated surface to slide against a stationary surface, which can occur during manufacturing or end use.
Assuring that the coefficient of friction of the coating is at a low value facilitates the process.
Wax emulsions reduce the coefficient of friction of the system. Harder waxes are more efficient in reducing the coefficient of friction.
3) Chemical resistance
Wax emulsions can aid in the resistance properties of a coating. Salt spray resistance of an exterior coating that will be exposed to severe weathering can be improved by adding a barrier enhancing wax.
4) Block resistance and release properties
Wax emulsions impart a non-stick character to a coating that decreases the tendency for blocking.
Unwanted transfer or adhesion of coating to a contacted surface is thus prevented.
5) Influence on Gloss
Wax emulsions can be used to control gloss to achieve a desired matt effect. An example of this is satin finish coatings for wood.
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.
Wax Emulsion Solutions
ATAMAN KIMYA is one of the largest suppliers of conventional and specialty wax emulsions, serving many industries.
Our emulsions have earned a reputation for superior performance, stability (even in long-term storage), consistency, applied cost and technical support.
Customers can choose from a range of wax emulsions based on specific processing and application requirements, and leverage our technical staff to make the best use of these products.
The name “wax emulsion” is in some sense a misnomer, because the product is really a dispersion of solid wax particles in a continuous phase of water.
The emulsion (as defined as twoimmiscible liquids) exists only when the wax is in a molten form as the emulsion is formed.
As mentioned above, a wax emulsion consists of wax, surfactants and water.
Other ingredients may be added as preservatives or to help stabilize the dispersion.
Wax emulsions provide a useful means of delivering wax to a product.
Wax emulsions are used in the manufacture of paper, paperboard and boxboard.
It is also used in the production of insulating board, hardboard and particleboard in the building products industry.
Wax emulsions are used to coat the surfaces of fruits to reduce moisture loss, extend storage life, impart gloss and protect the fruit from decay.
In paper coatings, the wax emulsion is added to the coating mixture to reduce dusting (from excess fi ller) during calendering, to increase water repellency, to improve flexibility and to raise gloss.
When used as sizing in paper, the wax emulsion helps prevent aqueous solutions, such as ink, from soaking into the paper and paperboard.
The emulsion is added continuously to the beater after the rosin size and alum and preferably just ahead of the paper machine.
When used in the making of gypsum, fi ber and particle board, the wax emulsion gives water repellency to the fi bers in the board.
The emulsion is usually sprayed on the wood particles, before the resin (which binds the fibers together) is applied and before the pressing of the fibers into board.
Industries served include:
Composite Wood: We provide specialty wax emulsions for oriented strand board (OSB), particleboard (PB) and fiberboard (medium and high density FB), hardboard, doors and moldings.
Packaging and Converting: Our specialized wax and wax/resin systems improve the manufacture of flat board stock and multi-ply paperboard using recycled pulp.
Coatings and Industrial Processing: Our waxes are used in coatings and in release applications for industrial processes.
Food-grade Applications: Our emulsions may be used as components in food packaging adhesives.
Wax Emulsions For Latex Gloves: Wax emulsions are useful at both the compounding and polymer dipping stages in the latex glove manufacturing process.
Add paraffin or microcrystalline waxes in the compounding stage to improve release properties, tack resistance, and anti-blocking.
Provide smoothness, abrasion resistance, and donnability by adding polyethylene, carnauba, or paraffin to the polymer coating formula in the polymer dipping or post treatment stage.
KEY BENEFITS
chemically inert and no reaction with latex
environmentally friendly and suitable for water-based systems
release aid for ease of stripping the glove from a form
COF reduction with improved donnability and abrasion resistance in a polymer coating
rub resistance
anti-blocking
Construction and Other Applications: We offer wax emulsions for use in paint and edge sealer formulations and in other applications
polyethylene wax additives
Our Polyethylene wax additives are used to enhance the performance of surface printing ink and overprint varnish (OPV) formulations.
Ataman’s wax emulsions improve rub and scuff resistance with minimal loss of gloss.
Key features and benefits
Improved rub characteristics
Small to large particle sizes available
Applications
Automotive coatings
Functional packaging
Furniture and wood coatings
Industrial coatings
Overprint varnish (OPV)
Paper and paperboard
Protective coatings
Marine coatings
Composite Wood: Wax is used in the engineered wood industry for two principal reasons: water absorption and lubrication.
Wax helps control water absorption and thickness swelling in a finished board, especially along the edges.
This temporary water resistance is important when boards are left outside at a job site or exposed to water prior to and after installation.
To ensure dimensional stability, board manufacturers must meet strict accreditation requirements on thickness swell and water absorption.
During the manufacturing process, wax also lubricates the individual fibers or flakes that make up composite boards, allowing individual particles/flakes to be transported more easily from the blender through the press.
For OSB mills, our wax emulsions provide optimal performance at reduced cost compared to molten slack waxes.
Our products also meet the requirements of standard PB and medium density fiberboard mills.
Our specialty wax emulsions achieve equal or greater control over water absorption and thickness swell compared to standard products, while delivering low-foaming properties at a lower total applied cost.
Packaging and Converting: Ataman’s specialized wax and wax-resin systems for the packaging and converting industries help manufacturers of flat board stock and multi-ply paperboard—using recycled pulp—to achieve remarkable results.
These specialized emulsions impart water resistance, an improved surface finish and higher levels of opacity for white stock.
Coatings and Industrial Processing: Our wax emulsions for use in many coating and release applications for multiple industries.
Spray-on coatings and release agents for industrial processes aid in the cleanup and maintenance of equipment such as blenders and presses by creating temporary protective barriers between substrate and plant environment, and by preventing process materials from sticking during the manufacturing process.
Removal of these wax barriers is easily accomplished with hot water or steam, saving on costly cleanup time.
Food-grade Applications: Ataman Kimya sells several emulsions that may be used as components in food packaging adhesives—under the conditions defined by the U.S. Food and Drug Administration (21 CFR 175.105, 176.170, and/or 176.180).
Construction and Other Applications: Our wax emulsions may be used in paints and edge sealers, providing a consistent neutral color and offering formulators maximum flexibility in pigmented applications.
Uses of our products include:
Industrial coatings
Fiberglass insulation
Tires
Pressure treated lumber
Our wax emulsions provide better distribution of the paraffin molecule to more effectively cover the dry furnish of chips, flakes or fines when compared to a molten wax application.
In addition, our products are nonflammable and emit less fumes and vapors.
Factors to be Considered While Formulating Wax Emulsions
Wax emulsions are now well established and extensively used in various aqueous formulations.
These ready-to-use wax emulsions can be easily incorporated into a formula by simple mixing.
The wax properties that have the greatest impact on formulation performances include:
1- The Melting Point: When curing is required, it is important that the wax has a lower melting point than the curing temperature
2- The Coating Thickness Layer: In order to maximize the wax effects, it is important to have the highest dried wax density to be at dried film surface.
Hence, the wax emulsion should have a particle size as closest as possible to the thickness of the coating layer
Sometimes a wax emulsion with a smaller particle size performs equally well, provided that the concentration is correctly adapted.
pH of the Wax Emulsion should be within approximately one unit of the system to which it is added.
If necessary, the pH of the emulsion can usually be adjusted using aqueous ammonia or acetic acid.
3- pH of the Wax Emulsion
4- The Type of surfactant can also influence compatibility with the other components, as well as the overall formulation stability. Matching the emulsion charge with the coating charge enhances stability.
5- The Order of Component Addition: In water-based formulations, the order of component addition can be a critical factor in maintaining stability. Agglomeration can be prevented and overall stability maximized by adding the wax emulsion last. A further dilution of the emulsion with soft or demineralized water before incorporation can also reduce the shock.
6- The Regulatory Aspects of Waxes: If the emulsion is intended for food contact use (in a coating or in a package), both the wax and other incorporated additives (emulsifiers, antifoams, biocides etc.) must be in compliance with applicable statutes and regulations (FDA, BfR, European Directives, Kosher Certification etc.).
7 -Determination of Wax content in a Formulation
Mechanism of Action of Wax Emulsions
The Blooming Mechanism
Molten wax particles float (or bloom) to the surface.
The coating cools and re-crystallization of wax particles takes place, forming a thin but continuous wax-enriched surface layer.
The softer the wax or lower the melting point, the more predominant the blooming mechanism becomes
The compatibility between the wax emulsion and other formulation components determines the wax migration rate
Blooming Mechanism for Formulating Wax Emulsions
The Ball Bearing Mechanism
In this case, solid wax particles migrate individually or protrude through to the surface.
By protruding slightly above the coating surface like ping-pong balls floating on a pool of water, they:
Act as a physical spacer, and
Prevent another surface from coming into close contact
Hard and high melting point waxes (HDPE, PTFE) operate using this mechanism under certain conditions. Both the particle density and the extent of protrusion influence the magnitude of the effect.
Once at the surface, the layer of wax particles has the ability to modify the Coefficient of Friction (CoF) of the substrate, imparting the desired characteristics. This explains why waxes are often classified as “Surface Conditioner Additives”.
Ball Bearing Mechanism for Formulating Wax Emulsions
Benefits of Wax Emulsions
Waxes are typical additives that significantly influence the surface properties of any coatings by modifying the surface free energy.
This has an impact on properties described below. All of them are critical properties in the paint, coating and ink applications.
Hence, waxes are often classified as Surface Conditioner or Modifier Additives.
Wax Emulsions as Anti-block Agents
Anti-blocking is a term defining a non-stick condition between two surfaces or the resistance to adhesion between two surfaces under the influence of:
Temperature
Relative humidity, or
Pressure
A very well-known example of a blocking condition is when a freshly painted window frame is closed too soon.
Sometimes, it can be very difficult to open the window again.
Factors affecting blocking include:
Coating surface-free energy
Topography of the coatings
Hardness, and
Tg of the polymer
Wax emulsions as anti-blocking agents are also used extensively for items that are coated, dried and immediately stacked, rolled up for storage or shipment.
Effect of Wax on Slip & Mobility
Slip properties (or lubricity) represent the ability of two surfaces to glide over each other without causing any mechanical damage.
Good slip properties require that the slip additive concentrate to the surface during and immediately after application and curing.
Generally speaking, the harder the wax, the better the slip properties
This is explained by the fact that wax crystals in the solid state are the main factor responsible for the characteristic of slip.
Soft & Hard Waxes
Thanks to this property, wax is widely used in applications:
Inks, OPV’s & Primers,
Paper, Film, & Foil Coatings
Metal coatings
Slip resistance is the ability to manipulate the surface energy by increasing the coefficient of friction of a cured coating. This can be realized by addition of wax surface modifiers.
In particular, polypropylene waxes or wax emulsions:
Control slip without adversely affecting scratch and mar resistance
Have good migration performance which results in an increased wax density on the coating surface
When formulating with polypropylene wax emulsions, it is crucial to adapt the particle size of the emulsion to the coating layer, in order to maximize the wax effects on the coating surface.
Wax emulsions are used for their slip resistance property in Floor Polish.
Effect of Wax on Abrasion Resistance
Abrasion resistance is produced by a combination of basic characteristics such as elasticity, hardness, strength, toughness, and in some cases, thickness.
Abrasion Resistance in Coatings using Wax Emulsions
It has also been established that a trend similar to that of slip additives exists between the wax hardness and the capability of the wax to resist rubbing damage.
Hard wax resists abrasion better than soft wax
Thanks to its mar, scratch and rub resistance properties, wax emulsions are used in a wide range of applications such as:
Architectural Coatings & Floor Polishes
Paper Film, & Foil Coatings
Inks, OPV’s & Primers
Metal Coatings
Wax Emulsions for Water Resistance
Water repellency or water resistance is another important property obtained or improved with waxes. As the name implies, this characteristic is the protection of a surface against water penetration (in liquid form).
Depending on formulation, the protection may be temporary or very durable and long-lasting.
Water Resistance in Coatings Using Wax Emulsions
Thanks to this property, wax emulsion is a key ingredient in a wide range of formulation for:
Wood Coatings
Architectural Coatings & Floor Polishes
Effect of Wax on Touch & Feel
Although coatings are usually applied to provide optical effects (color, gloss or matting etc.) or to protect a substrate, some applications also require the surface to have tactile properties.
In modern car interiors, coatings with a soft-feeling are applied on plastic substrates (mainly PVC) such as instrument panels and door handles to convey a “leather-like touch”, i.e. a feeling of smoothness and luxury.
With electronic devices (PCs, mobile phones, etc.) a “soft-feeling” effect created by specialized coatings is becoming increasingly more in demand.
By employing a coating that incorporates coarse wax particles, a rough and uneven surface is created at the microscopic level that is very similar to that observed with matting agents.
Because tactile properties are largely dependent on the coating formulation, it is important that the wax particles protrude through the coating layer and this requires a particle size larger than the film thickness.
Thanks to this texturizing effect, wax emulsions are commonly used in Wood and Plastic Coatings.
Matt Effect Using Wax Emulsions
Providing wax dispersions have a particle size much higher than 1 µm, they will significantly reduce the gloss, by introducing micro-roughness on the coating surface.
The so-created uneven surface will cause the light to be scattered.
The degree of the micro-roughness is determined by the number of particles present at the surface, which directly depends on wax properties such as:
Particle size and particle size distribution
Particle density
Amount of matting agent incorporated
Matt Effect using Wax Emulsion
Thanks to this matting property, wax emulsions are widely used in wide range of applications such as: Architectural, Wood coatings and Inks, OPV’s & Primers.
Effect of Wax on Black Heel Marks
Black heel marks occur in a floor coating when the heel or sole of a shoe leaves residue on the floor after a shoe scuffs or scrapes the coating surface.
Grocery carts, platform trucks, hand trucks and fork lifts can all produce black marks.
By reducing the coefficient of friction of the coating, carefully selected waxes such as HDPE will have better mobility across a coating surface improving the heel mark resistance.
Thanks to its heel mark resistance property, wax emulsions are used in Floor Polish.
Wax Types and Properties
Wax is a generic term that encompasses materials that have some specific properties such as:
Solid at 20°C, varying from soft / plastic to brittle / hard
A mp > 40°C without decomposing
A relatively low viscosity slightly above the melting point
Transparency to opaque, but not glass-like
Buffable under slight pressure
This includes:
Natural products based on C16 – C 36 Fatty Acids or
Some synthetic polymers with Mw from 700 to 10.000
Waxes are often classified according to their origin as illustrated in the table below:
Naturally Occurring Waxes
Synthetic
Waxes
Animal Vegetable Mineral
Beeswax Carnauba Montan PP, PE & PTFE
Lanolin Candellila Paraffin Fischer-Tropsch
Lanocerin Jojoba Microcrytalline Fatty Acid Amine
Shellac Ouricourl Intermediate PTFE
Ozokerite Polyamide
Where:
PP = polypropylene
PE = polyethylene
HDPE = High Density Polyethylene
PTFE = Polytetrafluoroethylene
Table below summarizes the main wax properties and corresponding effects imparted or improved in paint, coating and ink formulations.
Types, Properties and Main Performances
Carnauba
High melting naturally occuring wax
Different grades (T1, T2, T3)
Hard & brittles
Excellent clarity
Generally Recognised As Safe
Slip & Lubricity
Anti-Blocking
Mar Resistance
Paraffin
Various grades, hence properties depending on refinement degree
Hard to oily feeling
Mainly composed of straight alkane chains, hence some parafffin’s have good crystalline structure, giving excellent barrier effects against water repellency
Very low polarity
Anti-Blocking
Water Repellency
Slip & Lubricity
PE
Obtained by polymerization of Ethylene monomers
Various grades, hence properties depending on Mw and polymerisation process
Two main families: LDPE and HDPE (Low and High Density PE) whose difference is the extend and type of branching
LDPE’s display more thoughness, better scuff / mar resistance and are more flexible
HDPE’s contribute to better slip properties and abrasion resistance
Slip
Abrasion Resistance
Anti-Blocking
PP
Obtained by polymerization of propylene monomers
Good film toughness but poor slip & lubricity properties
Not really a wax but often classify as such because of impact to surface properties
Anti-Slip
Anti-Blocking
Abrasion Resistance
PTFE
Obtained by polymerization of C2F4 monomers
High melting point and outstanding heat resistance properties (up to 600°F)
Give the lowest known CoF, hence excellent slip & lubricity, anti-blocking and abrasion resistance
Chemically inert
Not really a wax but often classify as such because of impact to surface properties
Slip & Lubricity
Anti-Blocking
Abrasion Resistance
Among the plethora of additives available today, waxes have a significant impact on many formulations or processes.
Even if used in relatively small quantities – typically below 3% solids content of the total composition – waxes impart or improve effects as various as slip and lubrication, abrasion resistance, anti-blocking, matting and water repellency – all critical properties in the coating and ink areas.
Hence, waxes are often classified as surface conditioner additives
Wax Definition and Types
The term ‘wax’ encompasses a large range of naturally occurring and synthetic material constituted from high fatty acids esters (typically C36 – C50) or from polymers (700 < Molecular weight < 10,000) that differ from fats in being harder and less greasy. It is, however, important to realize that the chemical composition alone does not determine a wax. The term wax should rather be seen as a generic term for materials that are/have:
solid at 20 °C, varying in consistency from soft and plastic to brittle and hard;
a melting point of at least 40 °C without decomposing, which distinguishes waxes from oils and from natural resins;
a relatively low viscosity at temperature slightly above the melting point; non-stringing but producing droplets, which exclude most resins and plastics.
Today, there are a large variety of waxes available on the market, often classified according to their origin.
Polypropylene (PP), polyethylene (PE) and poly tetrafluoroethylene (PTFE), although not real waxes, are very often associated with this class of surface conditioner additives because of the similar effects and performances they can provide
Wax Action Mechanisms
In order to minimize as much as possible the inevitable ‘trial and error’ phase in development work, it is important to understand how waxes really behave. To have a significant impact on the coating or ink properties, the wax must migrate to the surface and be present in sufficient quantity at the surface to impart the desired properties. Several migration mechanisms – well described in the literature – are generally proposed.6-9 These are:
The Blooming Mechanism. Molten wax particles float (or bloom) to the surface. The coating cools down and re-crystallization of wax particles takes place, forming out a thin but continuous wax-enriched surface layer. Usually, the softer (low-melting) the wax, the more predominant the blooming mechanism. Incompatibility between wax and coatings can enhance the migration phenomenon.
The Ball Bearing Mechanism. In this case, solid wax particles migrate individually to the surface. Then, they act as a physical spacer by protruding above the coating surface, preventing another surface from coming into close contact. Hard and high-melting-point waxes [high-density polyethylene (HDPE), PTFE] work through this mechanism in some conditions. Both the particle density and the extent of protrusion influence the degree of effects.
Once at the surface, the wax particles (or layer) have the ability to modify the Coefficient of Friction (CoF) of the film, imparting the required effect(s). This explains why waxes are often classified as surface conditioner additives.
Typical Effects Obtained with Waxes
Waxes are usually less expensive, more reliable and less often associated with side effects (e.g., recoatability) than other surface conditioner additives.2 In most cases, a decrease in intercoat adhesion is related to the usage of extremely non-polar waxes like paraffins. Furthermore, the obtained surface effect(s) generally last longer because wax particles migrate very slowly to the surface. Table 2 summarizes the typical effects obtained with the more important industrial waxes; bear in mind that the coating properties depend very much on the complete coating formulation.
Anti-Blocking
Anti-blocking is a term defining a non-stick situation between two surfaces, their resistance to adhesion under the influence of temperature, relative humidity or even pressure fusing the surfaces together. A very well-known example of a blocking situation is when a freshly painted window frame is too rapidly closed. Sometimes, it can be very difficult to open the window again. Factors affecting blocking include the coating surface-free energy, topography of the coating, the hardness and the Tg of the polymer. HDPE, paraffin and carnauba waxes are typically used to counteract blocking. Anti-blocking agents are also very useful for any type of items that are coated, dried and immediately stacked or rolled up for storage or shipment.
Slip Aid
Slip represents the ability of two surfaces to glide over each other without causing any mechanical damages. Good slip properties require the slip additive to concentrate at the surface during and immediately after application and curing. A very interesting evaluation study with microcrystalline waxes clearly demonstrated that the harder the wax, the better the slip properties.10
This can be explained by the fact that a softer wax would tend to be more easily liquefied, and as a consequence, there remains less of it in a solid state to impart slip. In other words, the harder wax would have a relatively higher proportion of crystals in the solid state to impart slip.
Abrasion Resistance
Abrasion is a phenomenon caused by the mechanical action of rubbing, scraping or erosion.
Since intimately related to scratching and slip, it is not surprising that many slip aids also function as mar and abrasion-resistance additives.
Abrasion resistance is actually a combination of basic factors such as elasticity, hardness, strength, toughness, and in some cases, thickness.
Using the same series of microcrystalline waxes but with different hardness values, a similar trend was also established between properties of hard waxes and the capability of the wax to resist rubbing damage. Hard waxes resist abrasion better than soft materials.
The same trend was observed when comparing the behaviour of soft microcrystalline wax with hard PE and PTFE materials in the abrasion resistance of an ink formulation.
Furthermore, this study also demonstrated that:
Both PE and PTFE waxes function by the ball bearing mechanism, while the softer microcrystalline wax works via the layer (bloom) mechanism.
If the particle size of the wax is similar or slightly larger than the thickness of the printed ink film, the effectiveness of the wax is maximized.
Water Repellency
Water repellency, or water resistance, is another important property obtained with waxes.
As the name indicates, it implies the protection of a surface against water penetration.
The protection can be temporarily only (water resistance or repellency) or over a nearly infinite period of time (waterproof).
Also, water resistance generally implies the resistance to liquid water, whereas moisture resistance means the protection against water in a gaseous or vapor state.
Usually, paraffin waxes, including scale waxes (a lower refined paraffin grade containing up to 5 % oil), perform very well, particularly on porous surfaces.
The oil penetrates easily within the pores and fissures, rapidly imparting a very hydrophobic character to the treated surface.
Texturizer
Although coatings are usually applied to provide optical effects (colour, gloss or matting etc.) or to protect a substrate, some applications also require the surface to have tactile properties.
In modern car interiors, soft-feeling coatings are applied on plastic (mainly PVC) substrates like instrument panels and door handles, and convey a “leather-like” touch, i.e., a feeling of smoothness and luxury.
In coatings for electronic devices (PCs, mobile phones, etc.) a “soft-feeling” effect is demanded too, especially in Asia.
By incorporating coarse wax particles, a rough and uneven surface is created, very similar to that observed with matting agents.
Because tactile properties depend on the coating formulation, it is important that the wax particles protrude through the coating layer, hence require a particle size larger than the film thickness.
Formulating with Wax Emulsions
Wax emulsions are now well established and extensively used in aqueous formulations such as coatings, inks and OPVs, textile and leather treatments, polishes, paper and cardboard coatings, etc. These ready-to-use emulsions can be easily incorporated by simple mixing.
Their very fine particle size ensures an intimate and homogeneous incorporation within other ingredients of the formulation, maximizing the required effect(s).
Wax emulsions can be stabilized by either a steric mechanism (using with non-ionic emulsifiers) or by an electrostatic mechanism (using ionic emulsifiers, most often anionics).
Combining anionic and non-ionic emulsifiers gives the emulsion an optimum stability because wax particles are protected through both stabilization mechanisms, referred to as the electro-steric stabilization mechanism.
In addition to giving more flexibility in formulating, each stabilization mechanism has not only its own advantages and disadvantages but also significantly impacts on the overall formulation.
Wax properties that have the greatest impact on formulation performance include the chemical composition, the molecular weight, the melting point, the hardness and, in case of emulsions or dispersions, the particle size.
The end application and the coating application process (including the curing) also influence the wax selection.
When selecting a wax, it is important to consider:
Melting point.
When curing is required, it is important that the wax has a lower melting point than the curing temperature.
Thus, the wax can melt, migrate to the surface of the coatings, re-crystallize as the coatings cool and, eventually, form a continuous film for the blooming mechanism to occur.
Particle size and the particle size distribution should be slightly larger or at least equal to the film thickness.
This is particularly true if wax is hard (ball bearing mechanism).
Sometimes, a wax emulsion with a smaller particle size performs equally, providing that the concentration is correctly adapted.
In order to meet specific requirements, the particle size range can be controlled during the emulsification process.
pH should be within approximately one unit of the system to which it is added.
If possible, the pH of the wax emulsion can be adjusted by using aqueous ammonia or acetic acid.
Type of surfactant can also influence the compatibility with the other components, as well as the overall formulation stability.
Matching the emulsion charge with the coating charge enhances stability.
Order of component addition: In waterborne formulations, the order of component addition can sometimes be critical.
Agglomeration can be prevented and overall stability maximized by adding the wax emulsion last.
A further dilution of the emulsion with soft or demineralized water before incorporation can sometimes reduce the shock too.
Wax emulsions for masterbatches
Primary PE dispersions are very effective for dispersing pigments in masterbatches.
Fully bio-based wax emulsions for barrier coatings on paper and board.
Our novel vegetable wax emulsions are durable, renewable and fully natural.
Self-crosslinking paraffin emulsion for water repellency
A state-of-the-art self-crosslinking paraffin emulsion that takes water repellency to the next level is now available.
Fully biodegradable wax emulsions
Various product options can be offered that are based on fully biodegradable (and therefore repulpable and compostable) ingredients. Effects like hydrophobicity, gloss, slip & blocking and durability are significantly improved.
Wax emulsions for the cold-end treatment of glass
Wax emulsions for the cold-end treatment of glass that exhibit high gloss, excellent durability and superb lubcricity.
Antislip additives for floor coatings
improvement of black heel mark resistance while offering anti-slip at the same time
High solids paraffin wax emulsions for suberb hydrophobicity
Safe and clean chemistry allow for food contact and cosmetic application
Self-crosslinking paraffin emulsion for hydrophobicity
A state-of-the-art self-crosslinking paraffin emulsion that takes hydrophobicity to the next level is now available.
HDPE wax emulsions for durability improvement of water based paints
High solids emulsions based on extremely hard HDPE wax for durability improvement of water based paints, by offering excellent scratch- and abrasion resistance.
Primary PE wax emulsions for metal die-casting release
Novel primary PE wax emulsions that offer suburb release and lubricity in metal die-casting.
Modified paraffin wax emulsion for hydrophobing wood
Excellent water beading in water based exterior paints and wood coatings.
WAX EMULSIONS FOR FRUITS AND VEGETABLES
Protective Barrier to protect
Anti-slip coating for paper and paperboard
Achieve high tilt angles with this food contact approved coating
Wax emulsions for sewability improvement of yarns
High solids LDPE wax emulsions offer excellent thread lubricity and prevent stitch holes and mistakes in woven fabrics.
Matt coatings for leather finishing
New HDPE wax dispersions offer a matt and white effect in leather finishes with excellent durability, polishability and soft touch.
Modified paraffin wax emulsion for hydrophobing textiles
Superb water repellency on textiles and non-wovens.
Carnauba wax emulsions for food contact applications
Control slip and eliminate blocking in water based coatings.
High gloss HDPE wax emulsions for leather finishing
HDPE wax emulsions that offer extreme high gloss in leather finishes in combination with excellent durability.
Antslip additives for floor maintenance products
Enhancement of anti-slip while maintaining high gloss.
Vegan carnauba wax emulsion with excellent hydrophobicity
Fully natural and plant-based wax emulsion that ticks all the boxes.
WAX EMULSIFICATION PROCESS:
High Pressure Homogenizers for wax emulsions are necessary because the wax is mixed with water.
Wax is immiscible in the water making it difficult to form an emulsion. This can be handled by use of surfactants and by various emulsifying processes.
Wax emulsion is a mixture of one or more waxes (oil base) in water.
Waxes are usually immiscible with water, and therefore, to make them miscible, surfactants are added.
Waxes have a significant impact on several formulations and processes.
It offers lubrication along with abrasion resistance, anti-blocking, matting, and water repellency properties to the resulting product.
This leads to its wide applications in paints & coatings, adhesives & sealants, cosmetics, textiles, and others.
The sources of waxes can be natural or synthetic, natural waxes includes beeswax (animal-based) and carnauba (vegetable based); and artificial waxes include paraffin wax, amide wax, polyethylene wax, polypropylene wax, and montan wax, among others.
The significant growth of the paints and coatings industry across the globe is likely to be fueling the growth of the global wax emulsion market, as the wax emulsion is finding increasing use in the paints & coatings formulations in place of solvents, which is globally considered to be high in volatile organic content (VOC).
Additionally, wax emulsion finds vast usage in textile manufacturing as an additive to impart smoothness to the yarn, thread, and eventually fabric; reduce the breakage rate of yarn by providing lubrication; improves strength during knitting fabric; and serves as a protective agent for anti-wrinkling and free finishing fiber woven fabrics, among others.
The growth of the global textile industry due to rising consumer purchasing power and changing lifestyle is further driving the growth of the global wax emulsion market
Wax Emulsion Market Segment Analysis – By Type
Synthetic segment held the largest share of more than 55% in the Wax Emulsion market in 2020. Synthetic wax emulsions are synthesized from synthetic polymers such as polyethylene, polypropylene, polytetrafluoroethylene, and many more. Synthetic wax emulsions are long-lasting, abrasion-resistant and provide good protection from contaminants like dust, grime, and corrosion. Thus, the availability of synthetic wax emulsion with varied properties makes it suitable for numerous applications including paints & coatings, cosmetics, and construction, significantly augmenting the market growth. However, increasing environmental concerns are driving the demand for natural wax emulsions such as Lanolin, Beeswax, Carnauba, and Candellila waxes.
Polyethylene wax segment consists of low-density polyethylene (LDPE) and High Density Polyethylene (HDPE) and is obtained by polymerization of Ethylene monomers. Physical attributes such as water-repellence, abrasion resistance, slip control, lubrication, and anti-blocking are contributing to the growth of polyethylene wax emulsion. Polyethylene wax emulsion manufactures more easily and is cost-effective. Surging use of polyethylene wax emulsion in lithographic and flexographic inks for an improved rub and mar resistance and slip characteristics also aids the market growth.
Wax Emulsion Market Segment Analysis – Application
Wood Coatings segment: Wax Emulsion And Application
Wax emulsion is used in woodworking industry to protect wood boards (Particle board, MDF, OSB) from water.
Wax emulsion has anti-dust effect which is important while boards are sawing up or grinding.
Application of wax emulsion makes the plate surface smoother and softer which more than twofold increases the operating time of the grinding belt.
Wax emulsions have various applications.
They can be used e.g. for concrete curing and wood protection as well as on wood panels and textile fibers.
Some advantages of wax emulsion over melted paraffin:
Small particle size (about 1-5 micron) contributes to better paraffin wax penetration into the wood fiber and provides more efficient hydrophobization.
Wax emulsions mix well with the melamine- and carbamide-based resins. Wax emulsion acts as a water-repelling agent during the hot pressing of plates. The wax emulsion decomposes and melted paraffin wax hydrophobia the wood pate. Application of special emulsifiers leads to the decomposition of emulsion even before the bending agent becomes hardened which therefore strengthens the waterproof properties of plates.
It is simple to use because of liquid phase
No Storage Expenses – The Storage Temperature Of The Wax Emulsion Is 5-30°C, While For The Melted Paraffin Wax Is Over 60°C.
No Transportation Expenses – In Case Of Using The Wax Emulsion It Isn’t Necessary To Heat The Piping, As No “Freezing” Occurs Inside The Pipes.
Wax Emulsions Are Not incendiary; Therefore No Fire Risk Or injury Risk Could Be Caused By Its Appliance, While Such Risks Could Occur In Case Of Hot Melted Paraffin Wax.
Application Of The Wax Emulsion Leads To The 10-20% Reduction Of Resins Without Any Worsening Of The Physio-Chemical Properties Of The Plates.
Wax emulsions are extensively used in paints & coatings as they provide a consistent neutral color and offer formulators maximum flexibility in pigmented applications.
Wax emulsions also improve the durability of water-based paints, by offering excellent scratch- and abrasion resistance.
An increase in building and constructions has proliferated the demand for paint & coatings.
According to International Energy Agency (IEA), the global floor area in buildings expected to double to more than 415 billion square meter by 2050.
Additionally, total investments in the global buildings sector reached USD 5.7 trillion in 2019.
Hence, surging demand for paints and coatings as a consequence of huge constructional activities may bolster the growth of the wax emulsion market.
Wax Emulsion Market Segment Analysis – End-Use Industry
Textile and leather segment held the largest share of more than 25% in the wax emulsion market in 2020.
Wax emulsions are used in the textile and leather industry for waterproofing of textile and leather substrates, modifying the frictional properties of fibers, yarns, and sewing threads for better processability, and for enhancing the performance of finishing compounds such as softeners, silicones, and resins.
They also provide superior fabric properties such as improved flex abrasion resistance, tear strength, and sewability.
Owing to the above benefits the demand for wax emulsions is increasing from textile and leather industries.