Here is a compilation of 435 Technical Terms in Rubber Industry.
Being a long list, I have split this into two posts. Here are alphabets (A-L)
A
- Abrasion : The wearing away of a surface in service by mechanical action, such as rubbing, scraping or erosion.
- Abrasion Resistance : The ability of a rubber compound to resist mechanical wear.
- Abrasion Resistance Index : A measure of the abrasion resistance of a rubber relative to that of a standard rubber under the same specified conditions, expressed as a percentage.
- Absorption : The physical mechanism by which one substance takes up another substance (liquid, gas or vapor) into its interior.
- Accelerated Life Test : Any set of test conditions designed to reproduce, in a short time, the deteriorating effect obtained under normal service conditions.
- Accelerated Service Test : A service or bench test in which some service condition, such as speed, temperature or continuity of operation, is exaggerated in order to obtain a result in shorter time.
- Accelerator : A compounding material used in small amounts, with a vulcanizing agent, to increase the speed of vulcanization.
- Acid Resistance : The ability to resist the action of identified acids within specified limits of concentration and temperature.
- Acrylic : A polymer for which resistance to air and hot oil at temperatures above 30 degrees Fahrenheit are required.
- Adhere : To cling or stick together.
- Adhesion : Tendency of rubber to bond or cling to a contact surface.
- After Cure : Continuation of vulcanization after the desired cure is effected and the heat source removed (also referred to as Post-Cure).
- Ageing : To undergo changes in physical properties with age or lapse of time.
- Ageing, Accelerated : Tests run on various rubbers to find out, in as short a period as possible, the destructive influence of light, oxygen, heat and ozone.
- Ageing, Oxygen Bomb : A means of accelerating the change in the physical properties of rubber compounds by exposing them to action of oxygen at an elevated temperature and pressure.
- Ageing , Air Bomb : Similar to an oxygen bomb, but used with air.
- Ageing, Shelf : Ageing during storage.
- Agglomerate, Compounding material : A cluster of particles of one or more compounding materials loosely held together. Most commonly used to describe carbon black.
- Air Checks : Surface markings or depressions due to trapping air between the material being cured and the mold surface.
- Air Curing : Vulcanization of a rubber product in air, as distinguished from in a press or steam vulcanizer.
- Alpha Particles : Positively charged particles composed of two protons and neutrons (often referred to simply as helium atom molecule); characterized by limited penetration.
- Ambient Temperature : The surrounding temperature relative to the given point of application.
- Aniline Point : The lowest temperature at which equal volume of pure, fresh aniline and oil will completely dissolve in one another is the aniline point of the oil.
- Antidioxidant : An organic substance which inhibits or retards oxidation.
- Antiozonant : A substance that retards or prevents the appearance of cracks from action of ozone when the elastomer is exposed under tension, either statically or dynamically, to air containing ozone.
- Antirad : A material which inhibits radiation change.
- Aromatic Oil: A hydrocarbon process oil containing at least 35%, by mass, of aromatic hydrocarbons.
- Atmospheric Aging Resistance : Loss of physical properties due to the normal action of its surroundings (weather).
- Atmospheric Cracking : Cracks produced in the surface of rubber articles by exposure to atmospheric conditions.
- Autoclave : A vessel used for vulcanizing rubber products by means of steam under pressure.
- Axial Seal : A term usually applied to an O-Ring where the squeeze is applied on the top and bottom surfaces. Another term for face seal.
B
- Backrind : A molding defect in which the rubber adjacent to the parting line shrinks below the surface of the molded product, with the parting line often being ragged and torn.
- Back-Up-Ring : (Anti extrusion device) A ring of relatively hard and tough material, placed in the gland between the O-Ring and groove side walls, to prevent extrusion of the O-Ring.
- Bake Out : A process whereby a vacuum system is heated for a given time at some predetermined temperature to degas all the components, i.e. gauges, fittings, valves, seals.
- Banbury Mixer : A specific type of internal mixer used to blend fillers and other ingredients with an elastomer.
- Bank: The reservoir of material at the opening between rolls of a mill or calendar.
- Batch : The product of one mixing operation.
- Bench Marks : Two marks of known separation, applied to a specimen to measure the strain of the specimen during extension.
- Bench Test : A modified service test in which the service conditions are approximated, but the equipment is conventional laboratory equipment and not necessarily identical with that in which the product will be employed.
- Blank : A portion of a rubber compound of suitable volume to fill the cavity of a mold.
- Beta Particles : Negatively charged particles or electrons, characterized by limited penetration.
- Bleeding : Migration to the surface of plasticizers, waxes or similar materials, to form a film or bead.
- Blemish : A mark, deformity or injury which impairs appearance.
- Blister : A raised spot in the surface, or a separation between layers, usually forming void or air-filled space in the vulcanized article.
- Bloom : A dusty or milky looking deposit that sometimes appears on the surface of an molded product after molding and storage, caused by migration of a liquid or solid to the surface. Not to be confused with dust from external sources.
- Blow : The volume expansion that occurs during the production of cellular or sponge rubber.
- Blowing Agent : A compounding material used to produce gas by chemical or physical action, or both, in the manufacture of hollow or cellular articles.
- Bond : The term commonly used to denote the attachment of a given elastomer to some other member. Bonds may be classified by types, as follows:
- Mechanical – purely physical attachment accomplished by such means as “through” holes, interlocking fingers, envelope design, riveting, etc.;
- Cold – adhesion of previously vulcanized elastomer to another member through use of suitable contact cements;
- Vulcanized – adhesion of an elastomer to a previously primed surface using heat and pressure, thus vulcanizing the elastomer at the same time.
- Break : A separation or discontinuity in any part of an article.
- Break-Out : Force to inaugurate sliding. Expressed in same terms as friction. An excessive break-out value is taken as an indication of the development of adhesion.
- Brittleness : Tendency to crack when deformed.
- Brittle Point: The highest temperature at which a rubber specimen will fracture under sudden impact.
- Buna -N : See Nitrile.
- Buna-S : A general term for the copolymers of butadiene and styrene. Also known as SBR and GRS.
- Butaprene : See Nitrile.
- Buffing : The grinding of a vulcanizate, producing a roughened or velvety texture.
- Bumping, Moulding Process : The application, release, and reapplication of pressure prior to the start of vulcanization to vent entrapped gases, thereby facilitating complete filling of the mould cavities.
- Butt Joint : Joining two ends of a seal whereby the junction is perpendicular to the mold parting line.
- Butyl : A copolymer of iso-butylene and isoprene.
C
- Calender : A machine with two or more parallel, counter-rotating rolls, with controllable roll-to-roll spacing, rotating at selected surface speeds and controlled temperatures.
- Carbon Black : A material consisting essentially of elemental carbon in the form of near-spherical colloidal particles and particle aggregates. It is produced by partial combustion or thermal decomposition of hydrocarbons. Primarily used as a reinforcing agent, but also affects many other dynamic properties of a rubber compound.
- Catalyst : A chemical that, in small quantities, accelerates a chemical reaction without itself necessarily becoming part of the final product.
- Cell : A single small cavity surrounded partially or completely by walls.
- Cell, Closed : A cell totally enclosed by its walls, hence not interconnected with other cells.
- Cell, Open : A cell not totally enclosed by its walls and hence interconnected with other cells.
- Cellular Rubber : A generic term for materials containing many cells (either open, closed, or both) dispersed throughout the mass of rubber.
- Cellular Material, Collapse : An undesirable densification of a cellular material resulting from the breakdown of its cellular structure.
- Cement, Rubber : An adhesive that is either a liquid dispersion or solution of raw or compounded rubber, or both.
- Chalking : The formation of a powdery residue on the surface of a rubber, commonly resulting from surface degradation.
- Checking : The short, shallow cracks on the surface of a rubber product, usually resulting from damaging action by environmental elements.
- Chemical Bonding : A method of bonding rubber to inserts by applying special adhesives to the insert prior to molding.
- Chemigum : See Nitrile.
- Closure Dimension : Dimensions of a molded rubber product that are affected by flash thickness (mold closure) variation.
- Coagent: A compounding ingredient used in small amounts to increase the crosslinking efficiency of certain non-sulfur vulcanizing systems (especially organic peroxides), or to modify the properties given by such systems.
- Coating : A uniform layer of chemical primers or adhesives to produce a chemical bond between the rubber and substrate. May also refer to special surface treatments that can be applied to rubber to achieve special properties.
- Coated Fabric : A flexible product composed of a textile fabric and an adherent polymeric material applied to one or both surfaces.
- Coefficient of Thermal Expansion : Average expansion per degree over a stated temperature range, expressed as a fraction of initial dimension. May be linear or volumetric.
- Cold Checks : A defect on calendered sheeting consisting of surface roughness.
- Cold Flexibility : Flexibility following exposure to a predetermined low temperature for a predetermined time.
- Cold Flow : Slow deformation, under gravitational force, at or below room temperature. Sometimes referred to as “creep”.
- Cold Resistance : Able to withstand the effects of cold or low temperatures without loss of serviceability.
- Commercially Smooth : Degree of smoothness of a surface of an article which is acceptable for use.
- Compound : A term applied to a mixture of polymers and other ingredients to produce a usable rubber material.
- Compound, Standard: A control or reference compound prepared according to a prescribed formula and mixing procedure.
- Compression Molding : Molding process in which the material is placed directly in the mold cavity and compressed to shape by closure of the mold, under heat and pressure.
- Compression Modulus : The ratio of the compression stress to the resulting compression strain (the latter expressed in the direction of force). Compression Modulus may be either static or dynamic.
- Compression Set : The permanent deformation experienced by a rubber material when compressed for a period of time. The term is commonly used in reference to a test conducted under specific conditions wherein the permanent deformation, expressed as a percentage, is measured after a prescribed period of time. A low compression set is desirable in molded rubber parts such as seals and gaskets, which must retain their dimensions to maintain an effective seal.
- Conditioning (Environmental) : The storage of a rubber, under specified conditions (time, temperature, humidity) prior to testing.
- Conditioning (Mechanical): The prescribed program of deformation of a specimen prior to testing.
- Conductive Rubber : A rubber capable of conducting electricity. Most generally applied to rubber products used to conduct static electricity.
- Copolymer : A polymer consisting of two different monomers chemically combined.
- Corona Resistance : The ability of a rubber acting as insulator to withstand the effects of high voltage discharge. Indications of failure appear as surface cracks.
- Corrosion (Packing) : Corrosion of rigid member (usually metal) where it contacts packing. The actual corroding agent is fluid medium trapped in the interface.
- Corrosive (Packing) : A property of packing whereby it is assumed (often incorrectly) to promote corrosion of a rigid member of a trapped fluid.
- Cracker : A heavy-duty mill having two deeply corrugated or pyramid-cut rolls for breaking down a rubber or a mix, or for cutting rubber or a mix into pieces.
- Crack : A fissure originating in the surface of a rubber vulcanizate or product as a result of natural weathering.
- Crack, Flex : A fissure originating in the surface of a rubber vulcanizate, resulting from cyclic deformation (usually bending).
- Crack, Ozone : Fissures originating in the surface of a rubber vulcanizate, caused by exposure to an ozone-containing environment; these fissures are perpendicular to the direction of strain, and usually occur in rubbers having main chain unsaturation.
- Cracking : The sharp break or fissure in the surface. Generally due to excessive strain.
- Crazing : Formation of a random pattern of shallow cracks on a rubber surface usually due to ageing by light. Unlike ozone cracking, crazing does not depend on the presence of a tensile strain in the rubber.
- Creep : The progressive relaxation of a given rubber material while it is under stress. This relaxation eventually results in permanent deformation, or “set”.
- Crosslink : The chemical bond bridging one polymer chain to another.
- Crosslinking : Formation of chemical bonds between polymer chains to give a network structure.
- Cross-Linking Agents : A chemical, or chemicals, that bonds the polymer chains together to form a thermoset rubber product.
- Cross-Section : A seal as viewed if cut at right angles to the molding line, showing internal structure.
- Crystallinity : Orientation of the disordered long chain molecules of a polymer into repeating patterns. The degree of crystallinity effects stiffness, hardness, low temperature flexibility, and heat resistance.
- Cure : The thermo process that causes a chemical change in the raw stock, turning it into the finished rubber part . Also see Vulcanization.
- Cure Date : The date a rubber product was molded. Normally expressed, for example, as 1Q04, meaning the first quarter of the year 2004.
- Cure Meter : A testing device that measures the progress of vulcanization.
- Curing Temperature : The temperature at which the rubber product is vulcanized.
- Cure Time : The preset time needed to complete the curing process
- Cylinder : Chamber in which piston, plunger, ram, rod or shaft is driven by, or against, the system fluid.
D
- Damping : The quality of an elastomer to absorb forced vibrational energy. That property of a material or system that causes it to convert mechanical energy to heat when subjected to deflection; in rubber the property is caused by hysteresis.
- Deflashing : Any of various processes used to remove the waste edge from a molded rubber part.
- Degassing : The intentional, but controlled, outgassing of a rubber substance or other material.
- Density : The mass per unit volume of a material. Also referred to as specific gravity.
- Desiccant : A compounding material used to irreversibly absorb moisture, particularly for the purpose of minimizing risk of porosity during vulcanization.
- Die Swell : The difference between the dimensions of the cross section of an extrudate, and the corresponding dimensions of the die orifice from which the extrudate was formed. It is usually expressed as the percent increase in the cross-sectional area.
- Diene Polymer : A polymer formed from one or more monomer species, at least one of which is a diolefin.
- Dielectric Properties : The ability of a material to resist puncture due to electric stress. The property is expressed in terms of “volts per MIL thickness”.
- Dielectric Strength: The measure of a vulcanizate’s ability to resist passage of a disruptive discharge produced by an electric stress.
- Diffusion : The mixing of two or more substances (solids, liquids, gasses, or combinations thereof) due to the intermingling motion of their individual molecules. Gasses diffuse more readily than solids.
- Dispersion : The application of shearing forces to distribute one or more compounding materials uniformly throughout the mass of a rubber compound.
- Dumbbell Specimen : A flat specimen of rubber having a narrow straight central portion of essentially uniform cross section with enlarged ends. Used for testing purposes.
- Durometer : An instrument for measuring the hardness of a rubber; measures the resistance to the penetration of an indentor point into the surface of the rubber.
- Dusting : The application of a powder to a rubber surface, generally to prevent adhesion to another surface.
- Dynamic : An application in which the seal is subject to movement, or moving parts contact the seal.
- Dynamic Packing : A package employed in a joint whose members are in relative motion.
- Dynamic Properties : Mechanical properties exhibited under repeated cyclic deformation.
- Dynamic Seal : A seal required to prevent leakage past parts which are in relative motion. Also means a seal which is subjected to reciprocating, rotational, or oscillating motion.
E
- Ejector Pins : Pins or blades that, when activated internally to the mold, eject the part from the mold cavity. Sometimes referred to as “knock outs”.
- Elasticity : The property of an article which tends to return to its original shape after deformation. A rubber’s ability to return to its original size and shape after removal of the stress causing deformation such as stretching, compression, or torsion. It is the opposite of plasticity. The term elasticity is often loosely employed to signify the “stretchiness” of rubber.
- Elastomer : Any natural or synthetic material with resilience or memory sufficient to return to its original shape after major or minor distortion.
- Electron Volt : Unit of energy in atom calculations equal to 1.602 X 1012 ergs.
- Elongation : Extension produced by a tensile stress.
- Elongation, Percent : The extension of a uniform section of a specimen expressed as percent of the original length.
- Elongation, Ultimate : The elongation at the time of rupture.
- EPDM : Terpolymer of Ethylene-Propylene-Diene (noted for excellent ozone resistance).
- Erg : Unit of energy (C.G.S.) equal to one dyne centimeter, or approximately equal to the work done by force of One (1) milligram, causing a movement of one (1) centimeter.
- Evaporation : The direct conversion from liquid to vapor state of a given fluid.
- Explosive Decompression : The rupture of a rubber article caused by the rapid reversal of pressure, causing dissolved gases in the rubber to escape quickly to the surface of the vulcanizate.
- Extender : A material (usually organic) used to augment the polymer in a compound.
- Extensometer : A device for determining elongation of a specimen as it is strained.
- Extrudate: The material that issues from an extruder.
- Extruder : A machine designed to force rubber through an orifice, which is shaped to the geometry of the desired end product.
- Extrusion : The continuous shaping of a material during passage through a die.
- Extrusion (seal) : Distortion, under pressure, of a portion of a seal into the clearance between mating metal parts.
F
- Face Seal : A seal between two flat surfaces. In an O-Ring, this means it seals on the top and bottom, not the ID and OD. Also referred to as an axial seal.
- Fatigue Breakdown : The deterioration of an elastomeric product during repeated deformation.
- Fatigue Life : The number of deformations required to produce a specified state of fatigue breakdown in a test specimen or product that is deformed under a prescribed set of conditions.
- Feather Edge : The sharp, thin edge on parts, such as wiper seals and cups. (Also called “Knife Edge”).
- Filler : A solid compounding material, usually in finely divided form, which may be added in relatively large proportions to a polymer for technical or economic reasons. The most commonly used filler is carbon black. Most fillers also function as reinforcing agents.
- Filler, Inert : A filler having no reinforcing effect.
- Fixed Dimension : Dimensions on a rubber product that are not affected by flash thickness or mold closure variation.
- Flame Resistance : The resistance to burning of material that will not withstand combustion under ordinary conditions.
- Flash : Excess rubber left around a rubber part after molding, due to space between mating mold surfaces; removed by trimming.
- Flex Cracking : A surface cracking induced by repeated bending or flexing.
- Flex Life : The number of cycles required to produce a specified state of failure in a specimen that is flexed in a prescribed method.
- Flexometer : A machine that subjects a test specimen to repeated deformation by compression, tension, shear, bending, torsion or any combination thereof.
- Flex Resistance : The relative ability of a rubber article to withstand dynamic bending stress.
- Flexural Strength : The ability of a material to flex without permanent distortion or breaking.
- Flock : Fibrous filler sometimes used in rubber compounding.
- Flow : Ability of heated plastic, or uncured rubber, to travel in the mold and runner system during the molding process.
- Flow Cracks : Surface imperfections due to improper flow and failure of stock to knit or blend with itself during the molding operation.
- Flow Marks : Marks or line on a molded product, caused by imperfect flow of the raw compound during forming.
- Fluid : A liquid or a gas.
- Fluorocarbon : A polymer designed to meet the most rigid requirements in oils, solvents, synthetic lubricants and corrosive chemicals, at elevated temperatures.
- Friction : Resistance to motion due to contact of surfaces.
- Friction (Break Out) : Friction developed during initial or starting motion.
- Friction (Running) : Constant friction developed during operation of a dynamic O-Ring.
- Frosting : The formation of a matte, whitish appearance on a rubber surface exposed to air, resulting from the action of ozone. Often confused with bloom.
- Fuel (Aromatic) : Fuel which contains benzene or aromatic hydrocarbons; causes little swell of rubber.
- Fuel (Non-Aromatic) : Fuel which is composed of straight chain hydrocarbons; causes little swell of rubber.
- Furnace Carbon Black : A type of carbon black produced by the decomposition reaction of hydrocarbons, when injected into a high velocity stream of combustion gases under controlled conditions.
G
- Gamma Radiation : Electromagnetic disturbance (photons) emanating from an atomic nucleus. This type of radiation travels in wave form, much like X-Rays or light, but has a shorter wave length (approx. 1 Ado or 107 mm). It is very penetrating.
- Gasket : A deformable material clamped between essentially stationary faces to prevent the passage of matter through an opening or joint. A static mechanical seal.
- Gas Permeability : The degree to which a substance resists permeation of gas under pressure.
- Gates : The openings in an injection or transfer mold that ensure the even flow of material into the cavity.
- Gate Mark : A raised spot or small depression on the surface of an injection or transfer molded part, where the gates interface the cavity. (Also called “Sprue Mark”)
- Gland : The cavity into which an O-Ring is installed. Includes the groove and mating surface of the second part, which together confine the O-Ring.
- Glass Transition Temperature : The approximate mid-point of the temperature range over which a reversible change in a polymer occurs from (or to) a viscous or rubbery condition to (or from) a hard and relatively brittle one.
- Grain : The unidirectional orientation of rubber or filler particles in a rubber compound.green strength: the resistance to deformation of rubber stock in the uncured state.
- Groove : The machined recess into which a seal is fitted.ground vulcanized rubber: vulcanized rubber in particulate form; used as an extender or filler.
- Guayule Rubber: A form of natural rubber, cis polyisoprene, obtained from the shrub, Parthenium Argentatum.
- Gum Compound : A rubber compound containing only those ingredients necessary for vulcanization and small amounts of other ingredients for processing, coloring, and for improving the resistance to ageing.
H
- Hardness : Resistance to a disturbing force. Measured by the relative resistance of a material to an intender point of any one of a number of standard hardness testing instruments. (Also see Durometer).
- Heat Aging : A test for degradation of physical properties as a result of exposure to high temperature conditions.
- Heat Build-up : The accumulation of thermal energy generated within a material as a result of hysteresis, evidenced by an increase in temperature.
- Heat Deflection Temperature : The temperature at which a standard plastic test bar deflects 0.010 in. under a stated load of either 66 psi or 264 psi.
- Heat History : The accumulated amount of heat a rubber stock has been subjected to during processing operations. Incipient cure or scorch can take place if heat history is excessive.
- Hermetic Seal : An airtight seal having no evidence of detectable leakage.
- Homogeneous : A material of uniform composition throughout.
- Homopolymer : A polymer formed from a single monomer species.
- Hydrocarbon Solvents – Aromatic : Solvents having basic benzene structure, usually coat tar types such as benzene, toluene orxylene.
- Hysteresis Loss : The loss of mechanical energy due to hysteresis.
- Hysteresis : The conversion of mechanical energy to heat in rubber undergoing strain.
I
- Identification : Colored dots or stripes on seals for identification purposes; seldom used.
- Immediate Set : The deformation found by measurement immediately after removal of the load causing the deformation.
- Immersion : Placing an article into fluid, generally so it is completely covered.
- Impact : The single, instantaneous stroke or contact of a moving body with another, either moving or at rest, such as a large lump of material dropping on a conveyor belt.
- Impact Resistance: Resistance to fracture under shock force.
- Impact Strength : A measure of the toughness of the material, as the energy required break a specimen with a single blow.
- Inhibitor : A material used to suppress a chemical reaction.insert: typically, a metal or plastic component to which rubber is chemically and/or physically bonded during the molding process.
- IRHD (International Rubber Hardness Degrees) : International Rubber Hardness Degrees. An alternate method of measuring rubber hardness. IRHD units are approximately equivalent to Shore A durometer units, although a different apparatus is used.
- Injection Molding : Molding in which the rubber or plastic stock is heated and, while in the flowable state, is forced or injected into the mold cavity.
- Insert : Typically, a metal or plastic component to which rubber or plastic is chemically and/or physically bonded during the molding process.
- Isoprene-acrylonitrite Rubber : A low-plasticity copolymer with around 34 per cent ACN.
K
- Knit Line : An internal or external defect in a vulcanizate, where raw stock did not unite into a homogeneous mass during vulcanization.
- Knuckles : Small tough rubber pieces scattered throughout a bale of raw rubber that do not disperse easily or accept carbon black and other compounding materials during mixing.
L
- Leakage Rate : The rate at which a fluid (either gas or liquid) passes a barrier. Total Leakage Rate includes the amounts that diffuse or permeate the material of the barrier as well as the amount that escapes around it.
- Life Test : A laboratory procedure used to determine the amount and duration of resistance of an article to specific sets of destructive forces or conditions.
- Linear Expansion : Expansion in any one linear dimension, or the average of all linear dimensions.
- Liquid Curing Medium (LCM) : A molten phase, generally a mixture of sodium nitrate, that is used as a heating medium for the continuous vulcanization of a rubber mix, usually following extrusion.
- Logy : Sluggish, low snap or recovery of a material.
- Low Temperature Flexibility : The ability of a rubber product to be flexed, bent or bowed at low temperature without cracking.
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Rubber & Tyre Machinery World 