Epoxy Resins and Compounds Terminology

0 VOC means there are no "Volatile Organic Compounds" in the formulation. 

The resistance of a surface to rubbing or friction. A measure of durability as opposed to hardness.

Adhesives are substances used for sticking objects or materials together, such as glue. 

The term “aliphatic” derives from the Greek word for oil- aleiphar. In chemistry, aliphatic is an adjective meaning of, relating to, or being comprised of an organic Chemical compound having an open-chain structure without unsaturation.

In chemistry, aromatic is an adjective meaning of, relating to, or being comprised of an organic Chemical compound having conjugated unsaturations in a ring structure conforming to the 4n+2 rule for the number of carbons or other atoms in the ring.

A chemical is any substance that has a defined atomic composition. Typically referring to a compound or substance in its purest form. 

Coefficient of Thermal Expansion, or CTE, is the amount a material changes in length as the temperature changes (expansion and contraction).

Epic uses test method ASTM E831.

A composite is something made up of several distinct parts or elements. 

A compound is something composed of 2 or more separate elements in such a way that the atoms of the different elements are held together by chemical bonds. A chemical compound is a specific arrangement of atoms into a molecule.

Compressive strength is the force required per unit area to crush a material.

Epic uses test method ASTM D695.

Conductive is an adjective meaning to allow heat or electricity to travel through. The more conductive a material is, the easier it is for heat or electricity to move through it. 

Cure time is the amount of time a material takes to cure, or become solid. 

A dielectric constant is an essential piece of information when designing capacitors. It is the ratio of capacitance of a capacitor of a given configuration and insulator to the same configuration using air instead of the insulator.

Epic uses test method ASTM D150.

Dielectric strength is the voltage required to break down an insulator per a given thickness.

Epic uses test method ASTM D149.

Dissipation factor is the loss or dissipation of energy from the capacitor with a given insulator.

Epic uses test method ASTM D150.

Durometer is one of several measurements for the hardness of a given material—typically soft materials such as polymers, elastomers, and rubbers. The term is also used to refer to the measurement device itself.

In the 1920s, Albert F. Shore—founder of the Shore Instrument Company—developed a durometer device to measure the hardness of materials. The term “durometer” today usually refers to “Shore hardness.” Rigid materials like hard epoxy systems are measured using the Shore D durometer. Flexible materials like urethanes, similar in hardness to a tire or pencil eraser, are measured with a Shore A durometer. Materials with gel-like hardness are often measured with a Shore OO durometer.

See also Hardness.

Epic uses test method ASTM D2240.

An adjective meaning a material allows electricity to travel through it. 

How far a material stretches before breaking. 

Epic uses test method ASTM D638 or D412.

An encapsulant is a material used for encapsulating, or enclosing something in as if in a capsule.

The term epoxy specifically refers to the chemical functionality provided by the chemical elements C2H4O bonded into a cycle ether arrangement.  More generally, epoxy refers to the reaction products of molecules containing multiple epoxy functionality with various chemical hardeners to form solid thermoset materials.

Exotherm is the heat generated during the chemical reaction between a resin and hardener. These exotherms are dependent of mass and surface are. If a very large mass exotherms, it may result in a runaway reaction where the heat generated will cause thermal decomposition of the resin. Epoxy systems tend to exotherm more than urethanes and unfilled systems more than filled.

Treated as to be nonflammable. 

Having the ability or tendency to slow or stop the spread of fire. 

Flexural strength is also known as the force required to break a material while bending. Flexural strength is measured in terms of stress, and thus is expressed in pascals (Pa) in the SI system. 

Epic uses test method ASTM D790.

The point in time after mixing a two component material, or heating a one component material to its cure temperature, at which the material ceases to flow. The material will change from a flowable liquid to a continuous mass at this point.

Epic uses test method ASTM D3056.

The glass transition temperature, Tg, is the temperature at which a thermoset polymer changes from a glassy solid to an elastomer and back. Many physical and electrical properties of a material will change drastically before and after this transition.

Epic uses test method ASTM E1545 (sometimes E1356).

Hardness, or Shore Hardness, is a measure of a material's hardness to arbitrary standard values.

We measure hardness with Shore hardness gauges. These gauges impress a point into a surface under spring load. The gauge measures the resistance to the point's penetration. Harder materials are usually measured with a Shore Type "D" gauge, softer materials with a Shore Type "A" gauge, and very soft materials with a Shore Type "OO" gauge. See also “Durometer”.

Epic uses test method ASTM D2240.

High tear strength (or tear resistance) is a measure of how well a material can withstand the effects of tearing. 

Hydrolytic stability is a hydraulic fluid's capacity to withstand and resist chemical decomposition when exposed to water. Because water is one of the most common contaminants that a hydraulic fluid will regularly come into contact with, hydrolytic stability is an important characteristic.

Izod impact strength is an ASTM standard method of determining impact strength. A notched sample is generally used to determine impact strength.

Lap Shear strength is the ability of an adhesive to resist forces that cause the material to adhere to substrates. Shear strength is measured in a tensile test and is measured in pounds per square inch, based on the area of the sheared edge. The shear strength of a structural adhesive is the maximum shear stress in the adhesive before failing under tensile loading. 

Epic uses test method ASTM D1002.

All thermoset materials shrink as they cure. The source of this shrinkage is three-fold. First, thermoset materials tend to exotherm, or heat up as they cure. The materials flow into their final shape as a liquid that is warm and then set to a solid while warm. Upon cooling back to room temperature, the solid goes through normal contraction experienced by solids as they cool. This results in a part that is smaller than the mold or part it was originally poured into.

A second source of shrinkage in thermoset materials is due to the molecular reorganization that results in the cure of the thermoset material. When a mixture of molecules reacts chemically into a single, new molecule, the distances between atoms are reduced. This decrease in molecular length results in shrinkage.

Third, in general, liquids are less dense than solids. A thermoset material begins as a lower density liquid and ends as a higher density solid. This change in density results in shrinkage.

Linear shrinkage specifically refers to the change in length of an extended volume of thermoset material on cure.

Higher exotherm materials like rigid epoxies tend to shrink more than softer ones like urethanes. Filled materials display less shrinkage than unfilled ones.

Low VOC materials have reduced amounts of volatile organic compounds.

Mitigating thermal runaway is to slow a phenomenon with lithium-ion batteries, in which the lithium-ion cell enters an uncontrollable, self-heating state. Thermal runaway can lead to the ejection of gas, shrapnel, or other particulates. Effective methods of mitigating thermal runaway include thermal insulation and reinforced heat dissipation.  

Modulus is the stress verses strain relationship for a material. In general, a high modulus material tends to be rigid where a low modulus one would be elastomeric like a rubber band.

Epic uses test method ASTM D638/D412 tensile, D790 flexural, D695 compressive.

The release of trapped gas or vapors previously dissolved, trapped, frozen, or absorbed in a solid. 

A synthetic rubber formed from the polymerization of monomer 1, 3-butadiene. Polybutadiene has high resistance to wear. 

Any class of natural or synthetic substances composed of large molecules called macromolecules. Macromolecules are multiples of simpler chemical units called monomers.

Polyurethane is a class of polymers composed of organic units joined by urethane links.

The length of time that a catalyzed resin system retains a viscosity low enough to be used in processing.

Reaction Injection Molding (RIM) is a process for forming products such as automotive panels, turbine housings, and anything requiring a high strength to weight ratio. The process is similar to injection molding, but uses thermosetting polymers which require a curing reaction within the mold. The mixture is injected into a mold under high pressure with an impinging mixer, then allowed to remain in the mold long enough to expand and cure.

The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. For example, typical glass has a refractive index of 1.5, which means that light travels at 1 / 1.5 = 0.67 times the speed in air or vacuum. Two common properties of glass and other transparent materials are directly related to their refractive index. First, light rays change direction when they cross the interface from air to the material, an effect that is used in lenses and glasses. Second, light reflects partially from surfaces that have a refractive index different from that of their surroundings.

Resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers.

Not able to be forced out of shape without breaking; not flexible. 

A SDS (Safety Data Sheet) is an informational sheet which provides the procedures for handling and working with an Epic Resins’ material in a safe manner. An Epic Resins’ SDS provides information of physical data, storing and handling instructions, and emergency procedures to ensure maximum safety and understanding of the material.

Shear strength is the ability of a material to resist forces that can cause the internal structure of the material to slide against itself. Adhesives tend to have high shear strength. Shear strength is measured in a torsion test and is measured in pounds per square inch, based on the area of the sheared edge. The shear strength of a structural adhesive is the maximum shear stress in the adhesive before failing under torsional loading.

Synthetic materials which are polymers with a chemical structure based on chains of alternate silicon and oxygen atoms. 

Tensile strength measures the stress required to break a material per square area while stretching.

Epic uses test method ASTM D638 or D412.

Thermal conductivity is the rate at which heat transfers through a material.

Epic uses a C-Therm test unit for measuring thermal conductivity.

Thermal cycling is essentially a stress test where a material is cycled from very low temperatures to very high temperatures to test its resilience to thermal expansion and/or expose other structural weaknesses. 

The means of monitoring and controlling the temperatures produced by devices in electrical enclosures.

A phenomenon, especially in battery packs, where a single battery cell entering thermal runaway (releasing large quantities of heat) heats up neighboring cells, causing those neighboring cells to also enter thermal runaway, starting a chain reaction of overheating. 

The rapid cooling or heating of an object (typically at a defined rate of 10°C/min.) via the immediate transfer from one temperature to another. 

Thixotrope is a fluid where the viscosity is dependent on shear rate and shear history, an additive that imparts such behavior.

Epic uses test method ASTM D2196.

Underwriter Laboratories (UL) certifies products, facilities, processes, and systems based on industry-wide laboratory standards. They are one of the oldest and most widely trusted safety certification companies. 

A urethane is the solid that forms when a multifunctional hydroxyl containing compound (polyol) chemically reacts with a multifunctional isocyanate containing compound. The resulting solid would be a urethane or polyurethane.

Viscosity is a measure of the flow of a liquid material. It measures the amount of force required to deform (strain) a liquid a given distance.

Viscosity is commonly perceived as "thickness", or resistance to flow. Thus, water is "thin", having a lower viscosity, while molasses is "thick" having a higher viscosity. The study of viscosity is known as rheology.

Epic uses test methods ASTM D2196 and D4287.

Volume resistivity is the electrical resistance to current flow inherent in a unit volume of a material. It is typically reported in Ohm-cm as it is the resistance over a given area of material divided by its thickness.

Epic uses test method ASTM D257.