Element A substance which cannot be decomposed by chemical means into simpler substances; a substance consisting entirely of atoms of the same atomic number. Elongation In tensile testing of rubber, elongation is the increase in the distance between bench marks on a dumbbell strip or the distance apart of the grips holding a ring test piece, on the application of a load to the test sample.
It is expressed as a percentage of the original distance between the marks. Elongation at Break See Ultimate Elongation. ELS Evaporative light scattering. Embossing The impressing of a design on an uncured rubber surface by passing it through a calender fitted with an auxiliary roll engraved in the negative with the desired pattern. Empirical Formula The formula for a chemical compound which gives only the proportions of the different elements in the molecule and not their actual number, which may be calculated only from the molecular weight of the compound.
Emulsifying Agent A substance added to an emulsion to increase its stability and reduce the risk of separation of the two components. In latex work soaps are widely used as emulsifying agents. Emulsion A two-phase system consisting of minute droplets of one liquid dispersed in a second liquid with which it is incompletely miscible. Emulsion Polymerisation Polymerisation of a monomer or mixture of monomers which have been emulsified with soap in water. SBR, neoprene and nitrile rubbers are manufactured by the emulsion polymerisation process.
Endothermic Accompanied by the absorption of heat. Ends The warp threads of a woven fabric. The use of the term EPR for a copolymer of ethylene and propylene, and the use of EPT for a terpolymer of these monomers with a small amount of a diene to provide double bonds is common but is not recommended. Epichlorohydrin 1-chloro-2,3-epoxypropane, the basis of epoxy resin and chlorohydrin elastomers.
Epichlorohydrin Elastomers See Chlorohydrin Rubbers. EPM Abbreviation for ethylene-propylene rubber. Epoxide Resins Another term for Epoxy Resins. Rubber Basics Epoxy Resins These are thermosetting viscous liquids or brittle solids, the most widely used being those based on the condensation reaction between epichlorohydrin and bisphenol A. The name is derived from the Greek prefix epi meaning over or between, an epoxy material being an oxygen between compound.
They are used mainly as adhesives and as surface coatings on metals, wood, other plastics and glass. EPR Abbreviation for ethylene-propylene rubber. Ergonomics The engineering aspects of the study of the relation between human workers and their working environment. Escalator A slatted conveyor fitted above an open mixing mill and used to increase the efficiency of mastication by cooling the rubber before returning it to the mill nip.
Estate Brown Crepe Grades of crepe rubber made from lump and other high quality scrap made on rubber estates. Esters Organic compounds derived by replacing the hydrogen of an acid by an organic radical or group. Examples of ester plasticisers are tritolyl phosphate, dioctyl phthalate and dioctyl sebacate. Ethane The second member of the paraffin series of hydrocarbons. It is a constituent of the natural gas found in association with oil fields. Ethanol Another term for ethyl alcohol. Ethanolamines Organic compounds derived from ethanol and amino groups NH2. See Triethanolamine.
Ethenoid Plastics Those plastics made from substances containing an ethylenic linkage or double bond; the acrylic, vinyl and styrene groups of plastics. Ethers A group of organic compounds derived from two molecules of an alcohol by elimination of one molecule of water. The compound commonly called ether is diethyl ether.
Ethyl Alcohol The commonest alcohol see Alcohols and therefore often called simply alcohol. It is used as a solvent, as a fuel and in the manufacture of many other organic compounds.
Ethylene C2H4, a colourless flammable gas; first stable member of the olefin series of hydrocarbons. Ethylene-Acrylic Terpolymer This terpolymer is formed from methyl acrylate, ethylene and a carboxylic monomer. It has properties comparable to those of an acrylic.
- Ubuntu for Non-Geeks A Pain-Free, Get-Things-Done Guide.
- The Struggle Against the State and Other Essays!
- Related Products!
- 1 x 454g Pack of 88.9mm x 6.3mm Basics Rubber Bands - 6355525.
- A second series of lessons on the game of chess;
Ethylene Dichloride A liquid produced by the addition of chlorine to the ethylene double bond. It is reacted with sodium polysulphide to produce polysulphide polymers, trade name Thiokol.
Ethylene Glycol A colourless, syrupy, sweet-tasting liquid; the synthetic fibre Terylene is made by condensation polymerisation of terephthalic acid and ethylene glycol. Ethylene-Propylene Rubber A stereospecific polymer produced by the copolymerisation of ethylene and propylene with Ziegler-type catalysts. Ethylene-Propylene Terpolymer An elastomer consisting of a terpolymer of ethylene, propylene and a diene, e.
Ethylene Thiourea ETU, accelerator. Ethylene-Vinyl Acetate A copolymer of ethylene and vinyl acetate which processes like a plastic and performs like a rubber. The copolymer, of which there are various grades, is similar to rubber in softness and flexibility but can be injection moulded without vulcanisation. ETMQ 6-Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, antidegradant staining.
ETU Abbreviation for ethylene thiourea, an accelerator. EU Abbreviation for polyether urethane. EV Abbreviation for efficient vulcanisation. EVA Abbreviation for ethylene-vinyl acetate. Evaporation Conversion of a liquid into vapour, without necessarily raising the temperature to the boiling point of the liquid; solutions are concentrated by evaporating off the solvent.
One method of concentrating natural rubber latex is by the controlled evaporation of the liquid in which the rubber particles are dispersed. Evaporative Light Scattering This is used in polymer analysis, it involves the removal of solvent from a solvated polymer as it elutes down a drift tube and the isolated polymer particles then scatter light from the light source allowing molecular weight to be calculated. Even Speed When the rolls of a mixing mill or calender are travelling at the same surface speed they are said to be running at even speed.
See Friction Ratio. Exothermic Accompanied by the giving off of heat. Expanded Rubber A form of cellular rubber in which the cells are non-intercommunicating, self-contained units. It has low thermal conductivity. Expanded rubber is buoyant and does not absorb water and was therefore initially used in both the soft rubber and ebonite forms in the construction of lifebuoys and other marine buoyancy equipment. The most commonly used polymer is now polyurethane for both flexible and rigid systems.
These products are most usually formed by moulding or extrusion processes and have a solid outer skin around the cell structure. Organic blowing agents are used for this type of process.
Extender In the broadest sense, any compounding ingredient added to rubber to reduce the cost of the compound. The use of the term is now usually limited to certain cheap petroleum rubber processing oils. Extending Filler A filler which is added to a rubber with the sole object of cheapening the compound. See Reinforcing Fillers. Extensibility A term descriptive of the extent to which an elastomer can be deformed by the application of a tensile stress. Extension 1 In tensile testing of rubber, another term for elongation.
Extensisity Factor The surface area of a filler per cubic centimetre coming into interfacial contact with the rubber. Extraction A process for removing certain constituents of a mixture by treating it with a solvent which dissolves only the desired constituents. Extrudate A term descriptive of the product of extrusion especially where no particular shape is specified. Extruder A machine for carrying out the processing operation of extrusion; also historically termed tubing machine and forcing machine.
The majority of extruders use an electrically-driven screw to force the rubber to the head of the machine, but a piston-operated type has recently been introduced. Extrusion The process in which unvulcanised elastomer or thermoplastic compound is forced through a die to give long lengths of a definite cross-section. The compound is normally warmed by working on a mill but in some modern machines this is unnecessary and cold stock may be used. The feed strip is led into a hopper situated over a screw which compacts the stock and forces it up to the head of the machine and through the die.
In the production of tubing a core-bridge is fitted in the head. The extrusion principle is used in hose. Factice A compounding ingredient with the main functions of a processing aid or extender. Dark factice sulphur factice is produced by heating certain unsaturated oils principally rape seed oil with sulphur.
White factice sulphur chloride factice is prepared by treating rape seed oil with sulphur monochloride at normal temperatures. Factice is still sometimes referred to as rubber substitute or simply sub, but these terms are not recommended. In appearance factices are friable, slightly elastic materials, the colour ranging from white to dark brown depending on the method of manufacture.
Factice has been popular for many years as a lowgravity resilient filler, finding particular application in spread sheeting compounds vulcanised by the cold cure method, and in erasers where the factice content may be as high as phr. In recent years work has been done on the use of factice in quite small amounts, since it has been found to have accelerating powers.
Factices are available for use with most synthetic rubbers: SBR, polychloroprene, butyl, nitrile and chlorosulphonated polyethylene. Factories Acts The legislation which sets out, for the United Kingdom, the regulations governing industrial health, safety, welfare, hours of work, reporting of accidents, etc. Fahrenheit A temperature scale widely used in the US industry. On this scale 32 is the freezing point of water and the boiling point. See Celsius. Fatigue The weakening of an elastomer or rubber article due to subjecting it to a continually repeated series of distortions stretching, compression, bending, or any combination of these.
Fatty Acids A term applied to the whole group of saturated and unsaturated monobasic aliphatic carboxylic acids. See Oleic Acid and Stearic Acid. FEF Fast extrusion furnace grade of carbon black. See Furnace Black. Rubber Basics Festoon An assembly of weighted or tensioned rollers for suspending long lengths of rubber or fabric in a limited space. It may be arranged to store a limited amount of fabric during temporary stoppage of a following process and may then be termed an accumulator.
Fibre Often used nowadays in the sense of textile material, e. A fibre is fine, flexible, and very long in relation to its thickness. Ficus A genus of trees yielding a good type of natural rubber, of little commercial importance nowadays. The Ficus elastica is the well-known ornamental rubber plant. FID Flame ionisation detector. Field Latex Natural rubber latex, freshly tapped, before the addition of preservatives or before concentration.
FIFO The first-in, first-out principle of injection moulding; the material first plasticised is the first material to be injected. Filament A fine wire or thread. In textile technology the fine thread formed at the spinnerettes in the manufacture of synthetic and man-made fibres. See Continuous Filament. Filastic Process A method of impregnating textile fibres with latex. There is no natural affinity between the textile fibre and the latex particle; this is overcome by making the latex slightly acid and the surface of the textile strongly alkaline.
Filler A compounding ingredient added to rubber for the purpose of either reinforcing or cheapening the compound. See Reinforcing Filler and Extending Filler. Fine Hard Para The best grade of wild rubber formerly obtained from Hevea trees indigenous to the Amazon Valley, and originally exported from the town of Para. Finite Element Analysis A mathematical technique developed originally for predicting the stress-strain behaviour of complex shaped objects which do not lend themselves to simple analysis. The object is broken down into a large number of simple units or elements whose behaviour can be more simply calculated.
The net behaviour of all the elements is then added together to give the gross behaviour of the component. The range of applications is now very wide and includes thermal behaviour, high speed impact and fatigue. Developments in the capabilities of modern computers have opened this techniques up to a much larger spectrum of the industry and its potential has allowed designers much greater freedom and shortened the time to market of new products. FIPG Abbreviation for formed-in-place gasket. See Flowed-In Gasket.
Fire Retardant An additive used in rubber compounding to reduce the fire hazard. Firing Up Another name for burning.
New in Pipe solutions RCB Haul-off and WHC wheel capstan
Fischer-Tropsch Process A process for the manufacture of hydrocarbon oils, alcohols, fatty acids, etc. FKM Abbreviation for fluorocarbon rubber. Flammability The preferred term for what is generally called inflammability; it reduces the possibility of confusion between non-flammable and inflammable. Flap A shaped strip of rubber fitted between the beads of certain pneumatic tyre assemblies to protect the inner tube from damage by the beads and the wheel rim. Flash Another term for spew. Flash Point The temperature at which a liquid heated in a special test apparatus gives off sufficient vapour to flash momentarily on the application of a small flame.
Flat Bark Crepe The lowest grade of plantation crepe rubber. It is made from earth scrap rubber from latex which has fallen on the ground and any other plantation salvage scrap. It was formerly called Rolled Brown Crepe. Flat Curing When the curve of a particular property usually tensile strength of vulcanised rubber plotted against time of vulcanisation shows a levelling off or only a slow fall after the maximum has been reached, the compound or compounding ingredient under test is said to be flat curing, to have flat curing characteristics or to show a plateau effect.
Flex Cracking Repeated bending or flexing of a rubber causes cracks to develop in that part of the surface where tension stress is set up during flexing or, if this part of the surface contains a crack, causes this crack to extend in a direction perpendicular to the stress. Certain soft vulcanisates, for instance those prepared from styrene-butadiene rubber, show marked resistance to crack initiation, but it is possible for these vulcanisates to have a low resistance to growth propagation of cracks. It is important, therefore, to measure both the resistance to crack initiation by flexing and the resistance to crack propagation.
There are various test methods, one being the De Mattia Flex Test method which is suitable for rubbers that have reasonably stable stress-strain properties, at least after a period of cycling, and do not show undue stress softening or set, or highly viscous behaviour. The results obtained for some thermoplastic rubber should be treated with caution if the elongation at break is below,.
Fleximers Compounds of plastic resins or rubbers used for flooring and ships decking. Flexometer An instrument for the measurement of heat buildup in vulcanised rubber by a forced vibration method. Flocculation That type of coacervation in which are formed large numbers of very small agglomerates of polymer particles, termed floccs. Flooring The use of rubber as a floor covering continuous sheets, tiles or mats was one of its earliest applications but is now being challenged by a variety of plastics, mainly PVC.
Flowed-In Gasket A gasket made in situ by extruding the sealing compound on to a rotating component thereby forming a layer of compound which, after curing, becomes a gasket, solid or cellular as desired. Also known as formed in place gasket. Fluid Bed Vulcanisation A continuous process for the vulcanisation of extruded sections.
The heating medium is a bed of tiny glass spheres fluidised by steam or hot air. Fluidisation The technique of passing a gas into a solid which is in the form of tiny granules and thus making the solid behave as if it were a dense, viscous liquid. Fluidised materials may be easily piped from place to place, but a particular application in the rubber industry is the vulcanisation of extruded sections.
See Fluid Bed Vulcanisation. Fluorinated Elastomers Elastomers containing fluorine, also called fluorelastomers. These combine the good physical properties of organic elastomers with the thermal stability of inorganic materials. FMQ Abbreviation for fluoro methyl silicone. Foam Rubber A product produced exclusively from a liquid base, e. Latex foam has an interconnecting cell structure and is most commonly used for cushioning applications. Foamback A thin layer of rubber or plastic foam applied to knitted or woven fabrics, used mainly in the garment trade and in carpet backing.
Foaming Agent A substance which assists in holding the foam structure produced by whipping or frothing in the manufacture of latex foam rubber. Footwear Rubber, thermoplastic elastomers and PVC are employed in the manufacture of a wide range of footwear: trainers, shoe soles and Wellington. Forced Vibration The motion resulting from the application to a rubber specimen of an oscillating force. Forcing Another name for extrusion. Formaldehyde HCHO, a gas with an irritating smell. It is made industrially by the oxidation of methyl alcohol, and is used in the manufacture of phenolformaldehyde and urea-formaldehyde resins and plastics.
Basics | Capri Collections
Former Any specially shaped device on which a rubber product may be assembled, on which a product may be fitted to bring it nearer the cured shape or on which an article may be produced by dipping Formic Acid HCOOH, an organic acid which may be used in diluted form as the latex coagulant in the production of natural rubber. Formula 1 Mathematics A rule expressed in algebraic symbols; 2 Chemistry The representation of the kind and number of the atoms in a molecule of a compound, by means of letters and figures; 3 Rubber Technology The statement of the kinds and amounts of elastomers and compounding ingredients which comprise a rubber compound.
FPM Abbreviation for fluorocarbon rubber. Fractional Coagulation Coagulation of natural rubber latex by stages with the object of removing the yellow colouring matter in the first fraction. The latex in the second fraction produces a white crepe rubber. See Bleaching Agent. Frasch Process A method of obtaining sulphur from underground deposits where normal mining is not possible.
In Louisiana and Texas the sulphur lies beneath a layer of quicksand through which is driven a pipe carrying hot water to melt the sulphur and compressed air to drive it up to the surface. Free Radical A radical which can exist in the free or uncombined state. Such radicals are extremely reactive with themselves and with other neighbouring molecules. Free radicals are considered to take part in many reactions of importance to the rubber industry - vulcanisation, oxidation, ageing, polymerisation, etc.
Free Sulphur The amount of sulphur which has not combined with the rubber during the vulcanisation reaction. The determination of the free sulphur content is widely used in assessing the state of cure of a rubber product. French Chalk A hydrated magnesium silicate in the form of a soft white powder. It is used as a dusting agent,. Rubber Basics as an embedding agent in open steam vulcanisation and as an extending filler. Also called talc or soapstone and often referred to simply as chalk.
Freshening 1 Generally, the restoration of the tack of an uncured rubber surface by washing with solvent. Friction See Coefficient of Friction. Frictioning A calendering process in which hot soft unvulcanised rubber compound is applied to a fabric. The cloth passes between the bottom and middle bowls of a three-bowl calender; it travels at the speed of the bottom bowl and the faster middle bowl shears the rubber into the pores of the fabric. Friction Ratio The ratio of the relative surface speeds of adjacent mill or calender rolls; usually given in the form 1.
Frosting A dulling of the surface of vulcanised rubber articles considered to result from the action of atmospheric ozone, particularly in conditions of high humidity. It is quite different from blooming. Frozen Rubber Raw natural rubber which has been kept at temperatures lower than about 10 C 50 F becomes extremely hard or frozen and must be softened by heating before it can be processed satisfactorily.
The only form of thermal black now in common use is Medium Thermal MT black. See Thermal Black. Furnace Black A type of carbon black produced by burning natural gas or oil in a large furnace with a supply of air much lower than that required for complete combustion.
FVMQ Abbreviation for fluoro vinyl methyl silicone. D gives full details of the die and procedures used. It is used in a laboratory extruder to evaluate the extrudability or processibility of a rubber compound. Gas Chromatography GC is used in rubber analysis to obtain polymer type information by use of a pyrolysis approach, also to identify some additives. Gasket A flat sheet or shaped section of rubber compound or rubber textile composite fitted between two metal faces to make a fluid-tight joint.
Gauge 1 Any instrument for measuring, e. Gauge Pressure Pressure shown by a gauge; pressure above the pressure of the atmosphere. See Absolute Pressure. Gauze 1 A light-weight fabric of open texture. GC-MS Gas chromatography-mass spectroscopy is used to obtain extensive compositional information on rubbers. It can identify minor components of the sample such as the breakdown products of the cure system and the antidegradants. Geer Oven An electrically heated oven supplied with circulating kit, originally used in accelerated ageing tests.
Gehman Test A method of determining the stiffening of vulcanised rubber at low temperatures by submitting the rubber to torsion, as in BS A Gel Chemically, a colloidal solution which has set to a jelly. The term has a special significance in rubber technology. See Bound Rubber, Carbon Gel. Gelation Setting to a jelly: in latex processing it is a type of coagulation in which very little separation of the aqueous phase takes place during the gel formation.
Gel Permeation Chromatography The molecular weights of high polymers are normally measured by gel permeation chromatography GPC where both an average molecular weight and a molecular weight distribution are determined. A solution of the polymer is prepared which is then passed through a chromatographic column. The speed at which. At the end of the column there is a detector which establishes the concentration of the polymer in the solvent.
Detectors can be based on viscosity, infrared absorption spectra or light scattering. Gland A device for preventing leakage at the point where a reciprocating or rotating shaft emerges from a cylinder or vessel containing a fluid under pressure. Glass Hardening See Glass Transition.
Glass Temperature Another name for glass transition temperature. Glass Transition On lowering the temperature to which an elastomer is exposed the resulting changes are simple stiffening, crystallisation and glass transition second order transition shown by a rapid change in physical properties within a narrow temperature range. It is convenient to characterise a particular vulcanisate by the temperatures at which the stiffness is double or ten times that at room temperature, T2 and T10, and also by the temperature Tg at which the stiffness changes most rapidly.
Glass Transition Temperature Also termed glass temperature or Tg. The temperature at which the stiffness of an elastomer subjected to low temperatures changes most rapidly. If the glass temperature is close to the operational temperature the material will be leathery in its behaviour rather than rubber-like. Glycerine Glycerin, glycerol. A thick, syrupy, sweetish liquid used as a plasticiser, a mould lubricant and as a raw material for the manufacture of glyptal resins. Glyptal Resins Resins used as surface coatings prepared from glycerol and phthalic acid, now termed alkyd resins.
Goodyear Charles Goodyear is acknowledged by some as the discoverer of vulcanisation by the heating of a rubber-sulphur mixture. Many others including Ludersdorf and Hancock were also researching means to impart long term stability to rubber at around the same time. Goodyear did not patent his discovery until , whereas Hancock obtained a British Patent for a process of vulcanisation in Gooseneck Press A type of daylight press in which the frame holding the platens is in the shape of a gooseneck or swan-neck thus permitting full access to three sides of the platen area.
Gough-Joule Effect When rubber is stretched adiabatically without heat entering or leaving the system heat is evolved. The effect was originally discovered by. Gough in and re-discovered by Joule in See Wiegand Pendulum. GPC Abbreviation for gel permeation chromatography.
GPF Abbreviation for general purpose furnace carbon black. GPO Abbreviation for copolymer of propylene oxide and allyl glycidyl ether. Graft Copolymer A copolymer in which chains or branches of one polymer are grafted on to the main chain of the other polymer. See Block Copolymer and Heveaplus. Grain Difference in physical properties along and across a section of rubber compound resulting from the passage of the rubber through a mill nip, a calender nip or through an extruder die.
Green Raw or uncured. Green Budding An improved technique of bud grafting which may reduce by up to twelve months the nonproductive period in the life of the rubber trees, i. Instead of using budwood as the grafts, dormant buds derived from green cuttings are used.
Grinding Passing rubber compound through a tight nip of either a mill, a calender, or more usually a refiner to break down any agglomerates of compounding ingredients. Vulcanised scrap rubber may be reduced to crumb rubber by a grinding process. Ground Rubber Another term for crumb rubber. Guanidine Guanidine itself is imido-urea, but the term guanidines usually refers to the accelerators of vulcanisation, diphenylguanidine and diorthotolylguanidine. Guayule Rubber obtained from the shrub, Parthenium argentatum, native to north central Mexico and the adjacent part of Texas.
The rubber is not obtained by tapping but by harvesting the shrubs and crushing the woody tissue to separate it from the rubber. Intensive research, started in , has not succeeded in making guayule competitive with Hevea rubber, and since there has been no commercial production.
Gum Jargon for any rubber compound during processing. See High Gum and Pure Gum. Gutta Percha A hard resinous thermoplastic substance of the same chemical composition as rubber hydrocarbon but having the trans-structure. See Cis-trans Isomerism. Formerly extensively used for the insulation of submarine cables now superseded by polyethylene and in the early manufacture of golf balls now superseded by. Rubber Basics ionomers , but has now all but disappeared from the world market. Heat Build-Up The rise in temperature which occurs when rubber is deformed.
The energy used in deformation is not fully returned when the rubber recovers its original shape and the lost energy shows as a rise in temperature of the rubber. See Flexometer, Hysteresis and Resilience. Heat Capacity Heat or thermal capacity is the ratio of the change in heat energy of a unit mass of a substance to the change in temperature of the substance; like its melting point or boiling point, the heat capacity is a characteristic of a substance.
The measurement of heat and heat capacity is called calorimetry. Heat Distortion Temperature The temperature at which polymers cannot maintain structure or sag, it is close to the glass transition. Heater A term applied to a variety of vessels used in vulcanising rubber articles. See Autoclave and Dry Heat Cure.
Also refers to heater bands used on extruder barrels and similar machines. Heat History In the processing of rubber compounds mixing, rewarmings, calendering, extrusion heat history is a term used to indicate the total heat which has been received by the compound, particularly the temperatures reached by the rubber and the time it has been held at these temperatures. See Scorching. Heat-Sensitive Latex Latex used in the manufacture of dipped goods using a heated former.
The latex is heat-sensitised by addition of polyvinylmethyl ether PVME or certain polyglycols and the action of the hot former causes a layer of coagulated rubber to be deposited. Hevea Brasiliensis The most important species of the Hevea genus of the order Euphorbiaceae. All but a tiny proportion of the world supply of natural rubber is obtained from the Hevea tree originally native to the Amazon valley but now cultivated on a plantation scale in Indonesia, Thailand, Malaysia and a number of other equatorial countries.
Heveacrumb Natural rubber prepared to technical specifications by a process which converts the coagulum into finely divided granules which are subsequently dried and compacted into bales. The agent which brings about the crumbling is castor oil. Heveaplus The generic name of a series of raw materials made by intimate mixture or chemical combination of natural rubber and other polymeric or resinous substances. Hancock Thomas Hancock is designated the father of the rubber industry and to him Great Britain is indebted for the honour of being the first country to manufacture rubber successfully as a large-scale project.
His first major discovery, in , was the process of masticating and mixing raw rubber. His subsequent claim, in his Personal Narrative published in , that this was unquestionably the origin and commencement of the India-rubber manufacture, properly so called, has been amply verified since.
Hank A length of yarn which has been wound on a reel; also the standard length of yarn which varies with different textiles used in calculating yarn counts. Hardness Since all practical methods of measuring the hardness of rubber involve measuring the resistance to indentation, hardness may be defined simply as resistance to indentation. Hardness is an expression of the elastic modulus of the rubber. More specifically, the load required to press a ball of given diameter to a given depth into the rubber is proportional to its elastic modulus.
Hardness Testing The determination of the hardness of rubber. Instruments are either dead-load non-portable or spring-loaded pocket type BS A Hard Rubber Another term for ebonite. HCR Abbreviation for high consistency rubber, e. HDI Hexamethylene diisocyanate. See Isocyanate. Heat 1 Energy possessed by a substance in the form of kinetic energy of its molecules.
Gain or loss of heat may result in a rise or fall in temperature of the substance, or in a change of state solid to liquid to gas. The term heat is sometimes used in industry where temperature is meant. See Latent Heat and Sensible Heat. Hexamethylene Tetramine Also known as hexamine, hexa or HMT, a oncepopuIar aldehyde-amine type of accelerator for natural rubber, now used as a vulcanising agent for polyacrylate rubbers.
Hexane A solvent for natural and most synthetic rubbers except nitrile. It is a petroleum spirit existing in five isomeric forms; normal hexane has a boiling point of 69 C. HFA Abbreviation for higher fatty acids. HFP Abbreviation for hexafluoropropylene. High Gum Compound A rubber compound containing elastomer, curatives and the minimum of fillers. Also called a pure gum compound. High-Level Tapping Another term for ladder tapping.
High Polymer A chemical compound consisting of groups of atoms which are repeated almost indefinitely until very high molecular weights are achieved. They are organic nonblack reinforcing materials and find their greatest application in leather-type shoe soles. They facilitate the easy processing of relatively hard compounds due to a high degree of thermoplastic behaviour.
High Yielding A term applied to clones of Hevea trees which give a much higher yield of latex than ordinary rubber trees. The average yield in the s was under kg of rubber per hectare per annum. It is now more common to achieve a two- to threefold increase on these figures from modern planting material. HMT Abbreviation for hexamethylene tetramine. HNBR Abbreviation for hydrogenated nitrile rubber. Hold The part of a cure schedule during which the temperature is held at a specified figure. Holland Cloth A plain weave cotton fabric filled with a starchy substance to give it a glossy, non-adherent surface.
It was formerly much used to preserve a fresh tacky surface on unvulcanised rubber tyre, tube and belt repair patches but has been almost completely superseded by polyethylene film. Maillefer has added a Longitudinal Tape Applicator unit into its product portfolio recently.
One-day classroom training for four persons. Compatible applications Rubber Cable Production. Custom Tooling. Rubber Extrusion Technical Information. Materials Selection. Rubber Elastomer Properties. Quality Extrusions Pledge. Quality Extrusions Certification. Where We're Located. Contact Us. Rubber Extrusions Rubber Extrusion is a process which forces uncured rubber compounds through a die and into the desired shape. All Rights Reserved.
Related Rubber Basics
Copyright 2019 - All Right Reserved