Release Agents

Chemical used to prevent other materials from bonding to surfaces.

Release Coatings

Since the1950s, silicone coatings have been widely used on many paper and film liners for the purpose of releasing a variety of pressure-sensitive adhesive-coated materials. Up until the 1970s, these silicone release chemistries were based on high-molecular-weight reactive silicone polymers dissolved at low solids in such flammable/toxic solvents as toluene and xylene, and they all required high-temperature oven processing to cure them into durable release coatings.

The 1970s introduced a series of governmental regulations that put serious restrictions on the handling/disposal of the carrier solvents, driving the release-coating industry to push for friendlier silicone chemistries such as water-based silicone emulsions and thermal, solventless chemistries based on reactive silicone fluids.

The 1980s saw the commercialization of two families of ultraviolet light (UV)-and electron beam (EB)-curable silicone release coatings that, along with being 100% convertible, provided for non-thermal, room-temperature-curing chemistries—UV/EB “free radical”-curable acrylate silicones and UV/EB “cationic acid”-curable epoxy silicones.

By 1990, a new generation of cationic UV-cure epoxy-silicone chemistries was developed. The current generation of cationic UV-silicone technology provides a variety of targeted release characteristics on both paper and film substrates.               

Rheology Modifiers

Every adhesive and sealant has to have the correct flow properties to work in its targeted application. These flow properties are the result of the rheology of the material. This is true of such diverse materials as spray-applied adhesives and caulks.

Rheological modifiers are used to control how the product will respond to a variety of shear conditions. For example, a caulk must thin out as it passes through the nozzles of the applicator, but it must regain its viscosity quickly so that it forms the proper bead. Spray-applied adhesives must also thin out during application, but they need to recover their viscosity more slowly to allow for the proper flow-out on the substrate.

Softeners and Anti-Blocking Agents

Substances that reduce hardness, or reduce blocking to allow easier processing and handling.

Softeners and Anti-Blocking Agents, Beeswax

Natural wax composed mainly of esters of fatty acids and various long-chain alcohols.

Softeners and Anti-Blocking Agents, Coal Tar Oils

Oils obtained by the destructive distillation of bituminous coal.

Softeners and Anti-Blocking Agents, Hydrogenated Vegetable Oils

Oils made solid by way of hydrogenation process.

Softeners and Anti-Blocking Agents, Paraffin Waxes

Waxes used as a softener in a formulation. (See also Waxes.)

Softeners and Anti-Blocking Agents, Stearic Acid

Stearic acid is a waxy solid used in making candles, plastics, and other products, and for softening rubber.

Stabilizers

Stabilizers are chemicals added to a formulation to inhibit reactions between two or more other chemicals.

Stabilizers, Stearates

Stearates are the salts and esters of stearic acid.

Surface Conditioners and Modifiers

A material used to make a surface suitable for adhesive joining.

Surfactants and Dispersing Agents

A surface-active compound that reduces surface tension when dissolved in water or water solutions, or that reduces interfacial tension between two liquids, or between a liquid and a solid. There are three categories of surface-active agents: detergents, wetting agents, and emulsifiers. All three have the same basic chemical mechanism and differ chiefly in the nature of the surfaces involved. (See also Dispersing Agents.)

Surfactants and Dispersing Agents, Detergents

Detergents are surfactants or mixtures of surfactants that offer cleaning properties in dilute solutions.

Surfactants and Dispersing Agents, Dispersing Agents

Additive used to make the dispersion process easier and more stable.

Surfactants and Dispersing Agents, Silane

When added to adhesives, silanes can provide improvement in adhesion by reducing moisture attack at the interface. This results in improved moisture, temperature, and chemicals resistance.

Surfactants and Dispersing Agents, Wetting Agents

Substance used to reduce surface tension, thereby facilitating spreading or impregnation of a surface.

Tackifiers

Tackifiers are specialty resins used in the formulation of adhesives and sealants to add “tack” and improve adhesion. They may be hydrocarbon resins, rosin esters, phenolic resins, coumarone-indene resins, or terpene phenol resins, depending on the raw material.

Tackifiers provide increased tack and adhesion by creating a physical bond with the surface material, which maybe paper or an elastomer. They also deliver other performance advantages, such as improved hardness and reduced viscosity. Low-molecular-weight tackifiers, in particular, enable formulators to achieve low-viscosity formulations. This improves compatibility with the system, making it easier and faster to incorporate all materials, including fillers and plasticizers.

Tackifying resins enhance a broad range of adhesives and sealants, from hot melts to packaging adhesives. Depending on the level of tack required for the specific application, various levels of adhesion can be achieved simply by modifying system components. In general, the tackifier may account for up to 80-90% of a typical adhesive or sealant formulation.

Thickening Agents

All adhesives and sealants must have the proper consistency or viscosity. If the combination of binders, pigments, fillers, and other additives results in a formulation that is too thin, thickening agents will be added to increase the viscosity. (See also Rheology Modifiers.)

Thickening Agents, Bentonites

Absorbent aluminum phyllosilicate clay consisting mostly of montmorillonite.

Thickening Agents, Methyl Cellulose

Methylcellulose is a chemical compound derived from cellulose. It is a hydrophilic white powder in pure form and dissolves in cold (but not in hot) water, forming a clear, viscous solution or gel.

Thickening Agents, Water-Based

Water-based agents are added to a formula to increase viscosity.           

Thixotropes

Thixotropes are materials used to modify adhesive rheology.

UV Absorbers

UV light can cause the degradation and discoloration of many polymeric materials. UV absorbers are stabilizers that are added to polymers that are usually exposed in an outdoor environment. While many plastics and rubbers are intrinsically protected from UV radiation because of high levels of pigment loadings such as carbon black or titanium dioxide, clear resins or coatings need protection from UV radiation. The most commonly used UV absorbers/stabilizers are called hindered-amine light stabilizers (HALS) and are based on piperidine structures.

Viscosity-and Flow-Control Agents

(See Thickening Agents and Rheology Modifiers.)

Wetting Agents

Substance used to reduce surface tension, thereby facilitating spreading or impregnation of a surface.

Water Repellents

Water repellents are used to make a substance hydrophobic.

Water-Treatment Chemicals

Water-treatment chemicals eliminate impurities used in feed water for process applications. They are also used to control corrosion and other damage to water-tube boilers, heat exchangers, cooling towers, and chillers. Water-treatment chemicals include ion exchange systems, chemical softening systems, demineralizers, and other chemical-control systems.

Waxes

One of the most important ingredients in a hot-melt adhesive formulation is the wax. Waxes decrease the viscosity of the melt and the surface tension of the liquid adhesive. As hydrocarbon-type materials, waxes, in general, have a lower surface tension than the base polymer of the hot melt, and thus lower the surface tension of the overall adhesive. Certain waxes, known as microcrystalline waxes, not only reduce melt viscosity and melt surface tension but also reinforce the hot melt by forming crystallites that resist deformation under load.³

Waxes, Dispersions

Material used as a surface modifier.

Waxes, Emulsions

A stable mixture of one or more waxes in water.

Waxes, Microcrystalline

Microcrystalline waxes can reinforce a hot melt by forming crystallites that resist deformation under load.

Waxes, Synthetic

A synthetic wax is made from animal, mineral, or vegetable sources but is altered and refined. 

OILS AND FATTY ACIDS

Coconut Oil

Coconut oil, which is extracted from the kernel of mature coconuts, can provide a bio-based alternative to traditional petroleum-derived oils. The melting point of coconut oil is relatively high at around 76°F. It is clear in its liquid state and white when solid.

Dehydrated Castor Oil

Castor oil comes from the seed of castor plants, providing a bio-based alternative to traditional oils. The moisture content in castor oil can be reduced for urethane-based systems in order to minimize the amount of urethane that is polymerized by moisture during formulation.

FATTY ACIDS

A fatty acid is a carboxylic acid with a long unbranched aliphatic tail, which is either saturated or unsaturated.

Linseed Oil

Also known as flaxseed oil or flax oil, linseed oil comes from the flax plant’s ripened, dry seeds. The bio-based petroleum oil alternative has a clear, yellowish color.

Soybean Oil

Soybean oil, which is extracted from the soybean plant, finds broad use as a more sustainable alternative to traditional oils based on petroleum.

Sunflower Oil

Pressed from the seeds of sunflowers, sunflower oil can provide a bio-based alternative to traditional petroleum-derived oils.

Synthetic and Modified Oils

Synthetic or modified oils are manufactured or manipulated to achieve certain properties. As such, they can offer optimized structural uniformity and reduced impurities.

Tall Oils

Viscous, yellow-black liquid obtained as a byproduct of the kraft process.