ADHESIVE CONTACT TIME The period of time in which an adhesive, such as an epoxy, will remain in its tacky condition after application under specified conditions of temperature and humidity. It is the time available before the adhesive "dries" that something else can stick to it like fresh concrete or a second coating.
BINDER A system used to mix with aggregate to create a high strength epoxy mortar.
BLUSH An oily residue that forms on the surface of epoxies under some conditions.
CLASS Relates to the ASTM C-881 specification and identifies the surface temperature at time of application. Class A epoxies are intended for use when the temperature is below 40 ° F, Class B epoxies for 40 ° F to 60 ° F and Class C epoxies for over 60 ° F. NOTE: A Class C epoxy can work in a Class B condition but should not be used in place of Class A
COMPRESSIVE STRENGTH The ability of a material to support a load. For example, concrete usually has a compressive strength of 3000-4000 psi.
CURING AGENT A liquid chemical formulation that reacts with an epoxy resin to convert to a solid form. Synonyms are Part B, Reactor, or Catalyst.
ELONGATION The degree in which a product will stretch under tension before it breaks. This degree is expressed in a percentage of its original length. For example, a tensile elongation of 10% means the product stretched 10% more than its original length before breaking .
EPOXY RESIN A special liquid chemical formulation capable of converting to a solid form when mixed with a curing agent. Usually referred to as Part A
EXOTHERMIC A chemical reaction which generates heat. This type of reaction occurs when epoxies cure.
FINAL CURE The time required for an epoxy to reach 100% of its rated physical properties. Usually expressed in hours or days.
FLEXURAL STRENGTH The ability of a material to withstand bending before reaching the breaking point. Usually measured in psi.
GEL An epoxy when in paste-consistency form, can be applied on overhead or vertical applications.
GEL TIME The period of time it takes a liquid epoxy formulation to form a gel consistency during the cure process.
GRADE Denotes the viscosity of ASTM-formulated epoxies. Grade 1 is low viscosity; Grade 2 is medium viscosity; a Grade 3 describes non-sag grade materials.
HARDNESS The relative resistance of a material to indentation. In the plastics industry it is measured on a standard scale known as Shore.
HIGH MODULUS High-strength material that is rigid. Used specifically where high strength is needed (see "Modulus).
HYDROPHOBIC Repels water and uses this property to obtain adhesion in wet applications.
HYDROPHILIC Absorbs water and uses this property to attain adhesion in wet application where the introduction of moisture into the system and the resulting low modulus will not be dangerous.
IMPACT RESISTANCE The ability of a material to withstand breaking due to a sharp blow.
IMPREGNATION The process of thoroughly soaking a material such as wood, paper, or concrete with a synthetic liquid resin so that the resin is absorbed within the material.
INITIAL CURE The stage in which liquid epoxy, having become solid, has reached the majority of its ultimate physical properties. Usually expressed in hours or days.
LOW MODULUS The condition in which material is slightly flexible. Used where resilience will withstand expansion and contraction, vibration, impact and stress (see "Modulus") .
MODULUS Denotes the value of the stress ratio (load divided by area) to the strain (such as elongation) of a material. It is a measure of the relative flexibility and resilience of a material (i.e., rubber has a low modulus and steel a high one). Modulus is expressed in psi.
POLYMER A broad class of chemicals such as epoxy, polyester, nylon, acrylics, and polyurethanes. Usually made by causing a chemical reaction between two or more basic .chemicals called monomers.
POT LIFE The time it takes for a formulation to harden once two parts of an epoxy are mixed together. The time depends on temperature, volume, and quantity of the mixture.
PRIMER A coating applied on a surface to improve the adhesion of an application such as an epoxy system or other coating.
SHEAR STRENGTH The ability of a material to withstand a stress that makes two contacting parts slide upon each other in opposite directions.
SOLIDS Non-evaporating material.
TACK Stickiness of an adhesive.
TENSILE STRENGTH The ability of a material to withstand a load under tension (i.e., when being pulled apart). Tensile strength is expressed in PSI.
THIXOTROPIC Materials that are gel-like at rest, but fluid when agitated.
TYPE Describes the basic use to which ASTM-formulated epoxies are intended (i.e., Type I is an adhesive for old to old surfaces; Type ll. is for bonding new to old concrete; and Types III are binder/coatinqs (skid resistance).
VISCOSITY Measure of the flowability of any liquid system such as curing agents and resin. Expressed in a scale called centipoise (CPS).(Water has a viscosity of 1; heavy cream is approximately 1,500; Karo syrup is approximately 3000.)
