Surfactants for Emulsion Polymers

The terminology, surfactant is a connected word, appropriately derived from surface-active agent.  While used in an extensive range of industries, this blog post will focus on the use of surfactants in the CASE industry segment, where our products are applied in emulsion polymerizations and as stabilizers, dispersants, wetting agents and foam modifiers.  The main functions of surfactants in water-based CASE applications are to emulsify water-insoluble, hydrophobic monomers to facilitate polymerizations in an emulsion state, and to stabilized suspensions of the resulting synthetic polymers so they can be stored, formulated and subjected to shear forces.

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The process for creating micelles for monomer polymerizations is depicted below.

When used at low levels, our surfactant types have a profound effect on the properties and performance of the resulting emulsion polymer system.  The optimization of surfactant selection in CASE applications is therefore critically important.   Gantrade and Tiarco offer a diverse range of surfactant compositions and expertise to assist in meeting the requirements of most emulsion polymer applications.   

Types of Surfactants

Surfactants are classified into ionic and non-ionic surfactant types.  Ionic surfactants are classified by the charge on their polar head-groups and include both anionic (negative charge) and cationic (positive charge) surfactants.  The non-polar hydrophobic tail is typically a long-chain hydrocarbon, often derived from natural products such as fatty acids and alcohols.  The largest category is anionic surfactants, which dissociate in water into negatively charged head-groups.  Examples of anionic surfactants include sulfates (-SO4-), sulfonates (-SO3-) and carboxylates (-CO2-). The counter ions are usually ammonium, sodium, or potassium cations.  Conversely, cationic surfactants dissociate in water to positively charges head-groups such as quarternary ammonium salts (-R&#;N+R3-).  Cationic surfactants are higher in cost than the anionic families. Amphoteric surfactants have a dual charge, both positive and negative, on the head position of a hydrophobic molecule end, such as sulfo-betaines (-N+R2-R&#;SO3-). The positive and negative charges neutralize each other creating a net zero charge.

In emulsion polymerization, selection of the correct surfactant type is critical. The surfactant must enable a fast rate of polymerization, minimize coagulum in the process, control viscosity during polymerization and contribute to the performance of the final polymer including stability, gloss, physical properties and water resistance. Anionic surfactants are the preferred type of surfactant, with lauryl (dodecyl) sulfates and alpha-olefin sulfonates being among the common and economical.

The Gantrade-Tiarco Value Proposition for Surfactants

Gantrade and Tiarco-RST have teamed up to offer the emulsion polymer industry a broad portfolio of monomers, surfactants, dispersants, rheology modifiers, specialty chemicals, and industry-leading expertise.  With over four decades of supplying the CASE industry segment, Gantrade and Tiarco offer a wealth of experience and expertise to create real business value to our customers. Our combined resources and product lines allow us to rapidly respond to needs and to help position customers in future markets.

Tiarco&#;s surfactants&#; portfolio has a product for a wide range of applications in the emulsion polymerization, paint & coatings, adhesives & sealants, inks and related applications. The emulsion polymer experts and chemists at Tiarco are always available to assist customers with any formulation challenges and new product developments. Combining technologies from across their leading-edge chemistry portfolios can offer products with distinctive performance properties.

Tiarco employs a unique sulfation technology based on chlorosulfonic acid (CSA).  CSA is reacted with mid-cut fatty alcohols from palm and natural oils to produce a wide variety of surfactant types.  This environmentally friendly advanced manufacturing technology yields higher quality sulfated surfactants, with excellent consistency and minimal waste and clean-up requirements.  The CSA sulfation technology enables short turn-around times and greater flexibility in manufacturing.  Accordingly, Tiarco can custom synthesize or blend a wide variety of unique formulations to meet your special requirements, within strict quality limits.  Production capacities span small and large quantities.

Products are supplied as either &#;neat&#; compositions or specialty blends for performance enhancing applications, as follows:

• Anionic Surfactants

    

  Ammonium and sodium lauryl/laureth sulfates, derived from fatty alcohols using the CSA method.

   

  Alkyl Sulfates, Alkyl Ether Sulfates and Alpha Olefin Sulfates.
• Amine Oxides

    

  Lauramine oxides derived from natural feedstocks.
• Alkanolamides

    

  Coco/lauramide diethanol amines typically used in specialty blends.
• Amphoteric Surfactants

    

  Alkyl betaines and alkyl sultanes.

   

  Charge is dependent on the pH.
• Specialty Blends

    

  Anionic surfactants blended with other surfactant types.

Stanfax 969 (3 mole)

Stanfax (12 mole)

Stanfax (3 mole)

Stanfax (2 mole)

Stanfax (11 mole)

60

30

27

25

30

Emulsion Polymerization, Paints & Coatings, Adhesives, Sealants & Related Products

Stanfax 238

Stanfax 998 HV

Stanfax 998

Stanfax HV 

  Stanfax (1 mole)

Stanfax (2 mole)

Stanfax UM (2 mole)

Stanfax (3 mole)

Stanfax (3 mole)

Stanfax (12 mole)

25

25 

25.5

25.5

28.5

60

30

High Viscosity

Emulsion Polymerization, Paints & Coatings, Adhesives, Sealants, & Related Products

Ditto

Stanfax 234

Stanfax 234 LCP

If you want to learn more, please visit our website Quality Standards for Castor Oil Ethoxylates.

Amphoteric Surfactants

Amphoteric surfactants contain both a positive and a negative charge on their polar head-groups. The positive and negative charges neutralize each other creating a net-zero charge.  The pH of the emulsion will control the functional charge of the head position. In acidic solutions, amphoteric surfactants will exhibit a positive charge, similar to cationic surfactants. In basic solutions, amphoterics develop a negative charge, similar to anionic surfactants.  Amphoterics exhibit excellent compatibility with other surfactants.

The range of amphoteric surfactants we offer are summarized below.

• Alkyl Betaines
• Alkyl Sultanes
• Alkanolamides
• Concentrates

Specialty Blends

Surfactant blends, specially formulated to meet the diverse coating needs of a broad range of latex applications, are effective with SBR, VAE, EVA, Acrylics, Vinyl Acrylics, SBR-X (carboxylated), and many other aqueous emulsion dispersions. These blends are compatible with most fillers, thickeners, and auxiliaries. Designed to be both cost-effective and efficient at low usage levels, these products provide the formulator with a full range of coating capabilities.

The table below lists some of the specialty blends available from Gantrade and our partner, Tiarco.

Proprietary Blend of Surfactants and Dispersants

High efficiency foamer, which provides excellent foam stabilizations properties, viscosity builder. Enhances froth viscosity and rheological properties

Proprietary Blend of Surfactants and Dispersants

Premium foaming efficiency, combined with high level of foam stabilizer properties, viscosity builder. Enhances froth viscosity and rheological properties

Proprietary Blend of Surfactants and Dispersants

Moderate foaming efficiency, very high level of foam stabilization properties

Proprietary Blend of Surfactants and Dispersants

Enhanced foaming properties designed for commercial coating applications where bundle penetration is desired

Proprietary Blend of Surfactants and Dispersants

High efficiency foamer, which provides excellent foam stabilization properties, viscosity builder. Enhances froth viscosity and rheological properties

With these offerings, you can see that Gantrade-Tarco specialize in the synthesis and manufacturing of both anionic and amphoteric surfactants. In addition, we can sulfate most organic alcohols to meet specific needs. 

Partner for Your Success

Together, Gantrade and Tiarco offer a broad portfolio of monomers, intermediates, polymers, crosslinking chemistries, surfactants, rheology modifiers, dispersants, and related products that help to advance performance dimensions in emulsion-based paints and coatings, adhesives and sealants, inks and more.  Our combined teams and capabilities are always available to assist customers with formulation challenges and to tailor new products that can offer distinctive performance advantages. Whatever your specialty requirements, we welcome the opportunity to work jointly to enhance the performance of your products. Contact Gantrade today to get started. 

What is a Surfactant?

A surfactant is a substance, that when added to water, reduces the surface tension of the solution thus increasing its substrate wetting properties. At low concentrations, a surfactant has the property of migrating and being adsorbed on the interfaces present in the system. It alters the interfacial free energies of these interfaces. Thus, a surfactant is a surface-active agent.

Surfactants can be referred to by a variety of terms: soap, wetting agent, dispersing agents, substrate wetting additives, emulsifiers, surface-active agents, stabilizers, or solubilizers. They are necessary for the wet stage of polymers and coatings. Chemists use surfactants to change the composition of a liquid which enables specific properties that meet the needs for market applications. Since surfactants can also cause detrimental effects in the film, such as blisters, surfactant leaching, and less water resistance, chemists need to use the lowest levels possible while maintaining the coating&#;s performance.

Four Types of Surfactants

There are four basic classes of surfactants: nonionic, anionic, cationic, and amphoteric. All four types of surfactants can be utilized in pigment dispersions.

1. Nonionic Surfactants
Chemists use nonionic surfactants after polymerization to achieve stability, and then in the grind for wetting and dispersing pigments and again in the letdown to achieve optimal substrate wetting. Nonionic surfactants also help with stability of the formulation, heat age stability, freeze/thaw resistance, and in-can stability.

With nonionic surfactants, chemists should consider the HLB values as well as a cloud point. The HLB value plays a critical part in its functions and properties like emulsification, solubility, wetting, and dispersion. The cloud point affects storage conditions and if the cloud point is too low the coating may have phase separation and instability. For low-foam applications, the cloud point of the product should be just below the application temperature.

HLB (Hydrophile-Lipophile Balance)

HLB value is an empirical expression for the relationship of the hydrophilic ("water-loving") and hydrophobic ("water-hating") groups of a surfactant. The higher the HLB value, the more water-soluble (hydrophilic) the surfactant. The HLB value of nonionic surfactants is a measurement &#; on a scale of 1 to 20 &#; of the degree of water/oil solubility of a given surfactant.

The HLB of a particular surfactant is directly related to the structure of both its hydrophilic and hydrophobic parts and plays a critical role in its function and properties.

To calculate HLB, take the molecular weight of the surfactant hydrophilic chain, divided by the total molecular weight, and then multiply by 20.

Cloud Point

The cloud point marks the temperature above which an aqueous solution of a water-soluble surfactant becomes cloudy or turbid in appearance. Cloud points range from 0° to 100°C (32 to 212°F), limited by the freezing and boiling points of water. The cloud point is directional for determining storage stability and utility of surfactants at different temperatures.

As you can see, these two characteristics, HLB and cloud point, can be highly influential in determining the effectiveness of selected surfactants for different applications.

2. Anionic Surfactants

Chemists use anionic surfactants during polymerization as primary and secondary emulsifiers. They are used to control electrostatic stabilization and particle size. Unlike their nonionic counterparts, anionic surfactants don&#;t have a theoretical HLB value or a cloud point.

3. Cationic Surfactants

Chemists use cationic surfactants for their positive charge and anti-static properties. Typically, we see cationic surfactants used in textiles for their fabric softening ability and coatings for their anti-corrosive and anti-static properties.

4. Amphoteric Surfactants

Amphoteric surfactants are naturally cationic at low pH and anionic at high pH. They are very mild and non-irritating when used in cleaners and detergents.

Applications for Surfactants

To determine what surfactant to work with it is important to understand where, in what stage, will the surfactant be utilized and what performance is required.

Polymer chemists and formulators in paints and coatings use surfactants at nearly every stage:

• Polymerization

• Emulsifier

• Stabilizer

• Post-polymerization additives

• Grind, wetting out the pigments so they can be dispersed

• Letdown

• Lowering the surface tension for wetting out substrates

• Formulation stability

• Other performance properties

As with any other raw material evaluation, it is important to determine if the desired outcome was achieved and were there any effects to the performance with the addition.

For additional information on surfactants, please contact 
Joey Ruiz, Ph. D.
Principal Scientist, Solvay
(215)781- Office
 

For more information, please visit Surfactants Wholesale.