A review of isobutylene-based elastomers used in automotive applications.Isobutylene Noun 1. isobutylene - used also in making gasoline components butene, butylene - any of three isomeric hydrocarbons C4H8; all used in making synthetic rubbers butyl - a hydrocarbon radical (C4H9) polymers Isobutylene-based elastomers include butyl rubber butyl rubber: see rubber. , the copolymer copolymer: see polymer. of isobutylene and isoprene isoprene or 2-methyl-1,3-butadiene (ī`səprēn, by  'tədī`ēn), colorless liquid organic compound. , halogenated halogenatedpertaining to a substance to which a halogen is added. halogenated salicylanilides see rafoxanide, clioxanide. butyl rubbers, star-branched versions of these polymers and the terpolymer ter·pol·y·mer n. A polymer that consists of three distinct monomers. [Latin ter, thrice; see trei- in Indo-European roots + polymer.] isobutylene-para-methylstyrene-bromo-para-methylstyrene (BIMS BIMS Biomedical Science (educational course/major) BIMS Biobank Information Management System BIMS Butterflies In My Stomach BIMS Branson Interactive Multimedia Services (Branson, MO) ). A number of recent reviews on the manufacture, physical and chemical properties and applications of isobutylene-based elastomers is available (refs. 1-5). Structure In butyl rubber (IIR IIR - Infinite Impulse Response ) (figure 1), isoprene is enchained en·chain tr.v. en·chained, en·chain·ing, en·chains To bind with or as if with chains. en·chain  ment n. by
1,4-addition in the trans configuration (ref. 6). Depending on the
grade, the unsaturation un·sat·u·rat·ed adj. 1. Of or relating to an organic compound, especially a fatty acid, containing one or more double or triple bonds between the carbon atoms. 2. Capable of dissolving more of a solute at a given temperature. level due to isoprene, incorporation is between 0.5-2.5 moles Moles Definition A mole (nevus) is a pigmented (colored) spot on the outer layer of the skin (epidermis). Description Moles can be round, oval, flat, or raised. They can occur singly or in clusters on any part of the body. per 100 moles of isobutylene monomer monomer (mŏn`əmər): see polymer. monomer Molecule of any of a class of mostly organic compounds that can react with other molecules of the same or other compounds to form very large molecules (polymers). . The low content of isoprene along with a reactivity-ratio product near unity indicates that there is a random distribution of unsaturation throughout the chain. The molecular-weight distribution of butyl rubber also depends on the grade, with many products having a [M.sub.w]/[M.sub.n] of 3-5. The methyl groups adjacent to the unsaturation in butyl rubber prevent halogen halogen (hăl`əjĕn) [Gr.,=salt-bearing], any of the chemically active elements found in Group 17 of the periodic table; the name applies especially to fluorine (symbol F), chlorine (Cl), bromine (Br), and iodine (I). addition across the carbon-carbon double bond. Figure 2 shows the predominant structure (ca. 90%) as determined by [sup.13]C NMR spectroscopy Nuclear magnetic resonance spectroscopy most commonly known as NMR spectroscopy is the name given to the technique which exploits the magnetic properties of certain nuclei. This phenomenon and its origins are detailed in a separate section on Nuclear magnetic resonance. (refs. 7 and 8) that results from the introduction of bromine bromine (brō`mēn, –mĭn) [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2°C;; b.p. 58.78°C;; sp. gr. of liquid 3.12 at 20°C;; density of vapor 7. or chlorine at approximately a unit molar molar /mo·lar/ (mo´lar) 1. pertaining to a mole of a substance. 2. a measure of the concentration of a solute, expressed as the number of moles of solute per liter of solution. Symbol M, , or mol/L. ratio of halogen to the unsaturation level in butyl rubber. The butyl butyl /bu·tyl/ (bu´t'l) a hydrocarbon radical, C4H9. bu·tyl n. A hydrocarbon radical, C4H9. butyl a hydrocarbon radical, C4H9. polymer backbone appears to be relatively unaffected by the halogenation Halogenation A chemical reaction or process which results in the formation of a chemical bond between a halogen atom and another atom. Reactions resulting in the formation of halogen-carbon bonds are especially important. process. [Figures 1-2 ILLUSTRATION OMITTED] Brominated isobutylene-co-para-methylstyrene (BIMS), is the elastomer elastomer (ĭlăs`təmər), substance having to some extent the elastic properties of natural rubber. The term is sometimes used technically to distinguish synthetic rubbers and rubberlike plastics from natural rubber. formed by brominating poly(isobutylene-co-para-methylstyrene). The para-methylstyrene monomer can be present between 2-8 moles per 100 moles of isobutylene monomer, with the bromine level ranging from approximately 20-50% of the para-methylstyrene content. Physical properties The physical properties of butyl rubber are shown in table 1 (ref. 2). The physical properties of polyisobutylene, chlorobutyl rubber (CIIR CIIR Catholic Institute for International Relations CIIR Center for Intelligent Information Retrieval CIIR counterintelligence information report (US DoD) CIIR Canadian International Information Resource ) and bromobutyl rubber (BIIR BIIR Baylor Institute for Immunology Research (Dallas, Texas) BIIR Basic Imagery Interpretation Report BIIR Brominated Isobutylene-Isoprene Rubber ) are similar to those of butyl rubber.
Table 1 - physical properties of butyl rubber
(ref. 2)
Property Value Composition(a)
Density, g/[cm.sup.3] 0.917 B
1.130 CBV
Coefficient of volume expansion 560x10" BV
(1N)(V/T), K 460x10" CBV
Glass-transition temperature,
[degrees] C -75 to -6 B
1.95 B
Heat capacity, [C.sub.p]kJ/tkg.K)(b) 1.85 BV
0.130 BV
Thermal conductivity, W/(m.K) 0.230 CBV
Refractive index, [n.sub.p] 1.5081 B
(a). B - butyl rubber; BV = vulcanized vul·ca·nize tr.v. vul·ca·nized, vul·ca·niz·ing, vul·ca·niz·es To improve the strength, resiliency, and freedom from stickiness and odor of (rubber, for example) by combining with sulfur or other additives in the presence of heat butyl rubber; CBV CBV - call-by-value = vulcanized butyl rubber with 50 phr carbon black (b.) To convert J to cal, divide by 4,184 The rotational restriction of the polyisobutylene backbone due to the presence of the geminal-dimethyl groups results in a high monomeric monomeric /mono·mer·ic/ (mon?o-mer´ik) 1. pertaining to, composed of, or affecting a single segment. 2. in genetics, determined by a gene or genes at a single locus. friction coefficient and unique William-Landel-Ferry constants (ref. 9) compared to hydrocarbon elastomers of similar glass-transition temperature, for example natural rubber. The low vapor permeability of the isobutylene-based elastomers is apparently due to a low diffusion constant caused by limited chain mobility and to the low solubility solubility Degree to which a substance dissolves in a solvent to make a solution (usually expressed as grams of solute per litre of solvent). Solubility of one fluid (liquid or gas) in another may be complete (totally miscible; e.g. of gases in these saturated polymers (ref. 10). Chemical properties Polyisobutylene and butyl rubber have the chemical resistance expected of saturated hydrocarbons. Oxidative degradation is slow and the materials may be further protected by antioxidants Antioxidants Substances that reduce the damage of the highly reactive free radicals that are the byproducts of the cells. Mentioned in: Aging, Nutritional Supplements antioxidants, n. , for example hindered phenols phenols (fēˑ·n  lz),n. . Oxidative attack results in a loss of molecular weight, rather than in embrittlement Embrittlement A general set of phenomena whereby materials suffer a marked decrease in their ability to deform (loss of ductility) or in their ability to absorb energy during fracture (loss of toughness), with little change in other mechanical properties, such . In butyl rubber, the hydrogen atoms positioned [Alpha] to the carbon-carbon double bond permit vulcanization vulcanization (vŭl'kənəzā`shən), treatment of rubber to give it certain qualities, e.g., strength, elasticity, and resistance to solvents, and to render it impervious to moderate heat and cold. into a crosslinked network with sulfur and organic accelerators (ref. 11). The low degree of unsaturation The degree of unsaturation (also known as the Index of Hydrogen Deficiency or IHD) formula is used in organic chemistry to help draw chemical structures. The formula lets the user determine how many rings, double bonds, and triple bonds are present in the compound to requires the use of ultra-accelerators, such as thiuram or thiocarbamates. Phenolic resins, bisazidoformates (ref. 12), and quinone quinone Any member of a class of cyclic organic compounds comprising a six-membered unsaturated ring (see saturation) to which two oxygen atoms are bonded as carbonyl groups (−C=O; see functional group). derivatives can also be employed. Vulcanization introduces a chemical crosslink approximately every 250 carbon atoms along with the polymer chain, producing a molecular network. The number of sulfur atoms per crosslink is between one and four or more (ref. 13). Sulfur crosslinks have limited stability at elevated temperature and can rearrange re·ar·range tr.v. re·ar·ranged, re·ar·rang·ing, re·ar·rang·es To change the arrangement of. re to form new crosslinks. This results in permanent set and creep for vulcanizates exposed for long periods of time at high temperature. Resin cure systems provide carbon-carbon crosslinks and heat-stable vulcanizates; alkyl alkyl /al·kyl/ (al´k'l) the monovalent radical formed when an aliphatic hydrocarbon loses one hydrogen atom. al·kyl n. phenol-formaldehyde derivatives are usually employed. Typical vulcanization systems are readily available (ref. 2). The presence of allylic al·lyl n. The univalent, unsaturated organic radical C3H5. [Latin allium, garlic + -yl (so called because it was first obtained from garlic). halogens See Chlorine in halobutyl elastomers allows crosslinking by metal oxides and enhances the rate of sulfur vulcanization over that of butyl rubber. Halobutyl elastomers can be crosslinked by the same materials as used for butyl rubber, and by zinc oxide zinc oxide, chemical compound, ZnO, that is nearly insoluble in water but soluble in acids or alkalies. It occurs as white hexagonal crystals or a white powder commonly known as zinc white. , bismaleimides, diamines, peroxides and dithiols. The allylic halogen allows more crosslinking than is possible in elastomers with only allylic hydrogens. Halogen is a good leaving group A leaving group is an atom or group of atoms that detaches from a chemical substance. The remaining molecule or fragment remaining is known as the residual or main part. The term leaving group is dependent on the context of the statement. in nucleophilic substitution In organic and inorganic chemistry, nucleophilic substitution is a fundamental class of substitution reaction in which an "electron rich" nucleophile selectively bonds with or attacks the positive charge of a group or atom called the leaving group; rarely referred to as an reactions. When zinc oxide is used to crosslink halobutyl rubber Halobutyl rubber is mainly used for tire inner liner compounds, because of its low air permeability. Bromobutyl is superior to Chlorobutyl, but is more expensive. The halogen radical permits the rubber to bond to the other elastomers in the carcass compound , carbon-carbon bonds are formed through dehydrohalogenation to form a zinc halide halide: see halogen. catalyst (ref. 14). A very stable crosslink system is obtained for retention of properties and low compression set. Brominated isobutylene-co-para-methylstyrene crosslinking involves the formation of carbon-carbon bonds, generally through alkylation alkylation /al·kyl·a·tion/ (al?ki-la´shun) the substitution of an alkyl group for an active hydrogen atom in an organic compound. al·kyl·a·tion n. chemistry or the formation of zinc salts, for example zinc stearate Zinc stearate (Zn(C18H35O2)2) is a chemical compound. Zinc stearate is a zinc soap that repels water. It is insoluble in polar solvents such as alcohol and ether but soluble in aromatic hydrocarbons eg benzene and chlorinated hydrocarbons (refs. 15 and 16). Sulfur vulcanization is achieved by using thiazoles, thiurams and dithiocarbamates. Diamines, phenolic resins and thiosulfates (ref. 17) are also used to crosslink BIMS elastomers. The stability of these bonds combined with the chemically saturated backbone of brominated isobutylene-co-para-methylstyrene yields excellent resistance to heat and oxidative aging, and to ozone attack. Tire applications The tire is a high performance polymeric polymeric /poly·mer·ic/ (pol?i-mer´ik) exhibiting the characteristics of a polymer. pol·y·mer·ic adj. 1. Having the properties of a polymer. 2. composite of many rubbery components consisting of a tread area which includes the tread, base and cushion compounds, and the casing which includes the bead, carcass carcass, carcase 1. the body of an animal killed for meat. The head, the legs below the knees and hocks, the tail, the skin and most of the viscera are removed. The kidneys are left in and in most instances the body is split down the middle through the sternum and the vertebral plies plies 1 v. Third person singular present tense of ply1. n. Plural of ply1. and belts, and the sidewall side·wall n. 1. A wall that forms the side of something. 2. A side surface of an automobile tire, between the edge of the tread and the wheel rim. Noun 1. , inner liner, apex and chafer chafer Any of several species of scarab beetle (most in the subfamily Melolonthinae). Adult leaf chafers (genus Macrodactylus) eat foliage; the female deposits her eggs in the soil, and the larvae live underground for years, feeding on plant roots. compounds (ref. 18). Each component serves a specific and unique function, yet all function synergistically syn·er·gis·tic adj. 1. Of or relating to synergy: a synergistic effect. 2. Producing or capable of producing synergy: synergistic drugs. 3. to produce the desired performance. Isobutylene-based elastomers are used commercially in a number of the rubbery components of the tire, including the inner liner, non-staining black sidewall, white sidewall and white sidewall coverstrip compounds, and have been evaluated for use in tread compounds. Inner liner The inner liner is a thin layer of rubber laminated to the inside of a tubeless tire to ensure retention of compressed air compressed air, air whose volume has been decreased by the application of pressure. Air is compressed by various devices, including the simple hand pump and the reciprocating, rotary, centrifugal, and axial-flow compressors. . The liner is most commonly formulated with halobutyl rubber in order to provide good air and moisture impermeability im·per·me·a·ble adj. Impossible to permeate: an impermeable membrane; an impermeable border. im·per , flex-fatigue resistance and durability (ref. 18). The impermeability is thought to be caused by the close packing of the methyl side groups along the polymer backbone, resulting in slow movement of the chains (ref. 19). The integrity of the tire is improved by using halobutyl rubber in the inner liner since it minimizes the development of inter-carcass pressure which could lead to belt edge separation and adhesion failures, and inhibits the rusting of steel tire The Steel Tire was awarded to the winner of the annual college football game between the University of Akron and Youngstown State University. The trophy comes from the main products of the two cities; Akron for its rubber and Youngstown for its steel. cords (ref. 20). Inner liners for passenger tires can be formulated with a blend of chlorobutyl rubber and natural rubber (refs. 19-26). Hopkins, Jones and Walker (ref. 20) established that a chlorobutyl rubber/natural rubber liner would have to be thicker than that of a 100% chlorobutyl rubber liner in order to obtain the same air impermeability. The permeability increases essentially linearly with increasing natural rubber content (refs. 20 and 23). Von Hellens (ref. 23) showed that a 20 phr replacement of chlorobutyl rubber by natural rubber adversely doubles the permeability and reduces by half the adhesion to a natural rubber carcass compound. Bromobutyl rubber is used extensively in inner liner formulations (refs. 19, 20, 23, 26-33). Voigtlander (ref. 19) stated a number of factors that favor the use of bromobutyl rubber over chlorobutyl rubber. They are: * Superior adhesion and balance of properties (ref. 23); * increasing use of speed rated fires with lower profiles having higher surface area to air volume ratios; * requirement for fighter tires to reduce rolling resistance Rolling resistance, sometimes called rolling friction or rolling drag, is the resistance that occurs when an object such as a ball or tire rolls. It is caused by the deformation of the wheel or tire or the deformation of the ground. ; * use of high-pressure space-saver spare tires requiting a more impermeable impermeable /im·per·me·a·ble/ (-per´me-ah-b'l) not permitting passage, as of fluid. im·per·me·a·ble adj. Impossible to permeate; not permitting passage. liner; * better flex-cracking resistance after aging; and * bromobutyl liners, at half the gauge, are cheaper in material costs. A typical bromobutyl rubber finer formulation is shown in table 2 (ref. 28). Von Hellens (ref. 23) showed that increasing levels of processing oil and of N660 carbon black increases the permeability of a bromobutyl rubber compound. Alternatively, Navakoski, Juengel and Laube (ref. 31) reported that use of higher loadings (up to 145 phr) of a low surface area carbon black continually improves the permeability of a bromobutyl rubber compound, even at higher oil loadings. Table 2 - bromobutyl rubber inner liner formulation (re. 28) Bromobutyl rubber 100 phr N660 carbon black 60 Flexon 876 oil 15 Stearic acid 1 Zinc oxide 2 MBTS accelerator 2 Sulfur 1 Star-branched bromobutyl rubber (SB-BIIR) was developed for use in tire inner liner compounds to improve the processability of bromobutyl rubber (ref. 32). The polymer contains two distinct fractions, a linear chain and a star fraction containing as many as 30-40 arms similar in length to the linear chains. The very high molecular weight of the minor star fraction (5-20% by weight) contributes to increased green strength of the polymer without adversely affecting the relaxation process. This results in reduced mixing cycles to yield a similar mix quality, significantly lower die swell at the higher shear rates, improved extrudate surface quality and calendered cal·en·der n. A machine in which paper or cloth is made smooth and glossy by being pressed through rollers. tr.v. cal·en·dered, cal·en·der·ing, cal·en·ders surface appearance, and reduced shrinkage. In inner liner compounds, the modulus values are slightly higher and the elongation elongation, in astronomy, the angular distance between two points in the sky as measured from a third point. The elongation of a planet is usually measured as the angular distance from the sun to the planet as measured from the earth. at break values are somewhat shorter. Brominated isobutylene-co-para-methylstyrene has been evaluated for use in inner liners (refs. 28, 33 and 34) and affords improved heat and flex characteristics in off-the-road tires compared to a 100% bromobutyl rubber inner liner (table 3) (ref. 33).
Table 3 - comparison among inner lines (ref. 33)
CIIR BIIR BIMS
Polymer 1066 2222
Mooney viscosity, MV 1+4 @ 100 [degrees] 46 44 56
Mooney scorch, T5 @ 135 [degrees] C, min. 13 16 22
T90 (@ 160 [degrees] C, min. 15 12 12
Hardness, Shore A 40 42 40
100% modulus, MPa 1.0 1.0 1.0
Tensile strength, MPa 92 10 9
Elongation @ break, % 715 745 950
Strain energy (TS X elongation)
Initial 6,578 7,450 8,550
3 days @ 125 [degrees] C 3,791 4,878 7,986
4 days @ 100 [degrees] C 4,034 4,075 7,769
7 days @ 180 [degrees] C 0 0 2,682
Monsanto flex, kc
Initial 360 85 660
3 days @ 125 [degrees] C 53 23 260
4 weeks @ 100 [degrees] 25 11 200
Black sidewall The black sidewall is the outer surface of the tire between its bead and tread that protects the casing against weathering. It is formulated for resistance to weathering, ozone, abrasion abrasion /abra·sion/ (ah-bra´zhun) 1. a rubbing or scraping off through unusual or abnormal action; see also planing. 2. a rubbed or scraped area on skin or mucous membrane. and tear, radial and circumferential circumferential /cir·cum·fer·en·tial/ (-fer-en´shal) pertaining to a circumference; encircling; peripheral. cracking, and for good fatigue life (ref. 18). Traditionally, a blend of natural rubber and butadiene butadiene (by t'ədī`ēn), colorless, gaseous hydrocarbon. There are two structural isomers of butadiene; they differ in the location of the two carbon-carbon double bonds in the rubber is
used along with carbon black, curatives and a high concentration of
antidegradants to provide weather resistance (ref. 35). However, an in
situ In place. When something is "in situ," it is in its original location. surface-discoloration problem occurs upon exposure to ozone as a
result of using N, N'-disubstituted-para-phenylenediamine
antiozonants as protectants (ref. 36)In order to achieve a high-gloss black sidewall over the life of a tire, inherently ozone-resistant, saturated-backbone polymers are used in blends with diene Dienes are hydrocarbons which contain two double bonds. Dienes are intermediate between alkenes and polyenes. Classes Dienes can be divided into three classes:
EPDM Enterprise Product Data Management EPDM Ethylene Propylene Dimonomer (industrial/commercial piping/plumbing components) EPDM Engineering Product Data Management ), halogenated butyl rubbers and brominated isobutylene-co-para-methylstyrene elastomers have been used in conjunction with natural rubber and/or butadiene rubber (ref. 36). The ozone-resistant polymer must be used in sufficient concentrations and also be sufficiently dispersed to form domains that effectively block the continuous propagation of an ozone-initiated crack through the diene rubber phase within the compound. Halobutyl rubbers have been evaluated for use in tire black sidewalls (refs. 37-43). Lodocsi and Young (ref. 37) used a blend of chlorobutyl rubber, EPDM and natural rubber to improve static and dynamic ozone, and flex resistance of the compound. Particularly good results were obtained when 25% or greater chlorobutyl rubber and 20% EPDM rubber EPDM rubber (ethylene propylene diene monomer rubber) is an elastomer which is characterized by wide range of applications. EPDM rubber is used in vibrators and seals; glass-run channel; radiator, garden and appliance hose; tubing; washers; belts; and electrical insulation. are the elastomers used. Flowers, Fusco and coworkers (ref. 43) reported that a black sidewall consisting of a blend of chlorobutyl rubber for heat and flex resistance, and EPDM rubber for ozone resistance, offered a polymeric protection system that eliminated the need for chemical protectants for a natural rubber/butadiene rubber sidewall compound. Superior dynamic and static ozone resistance was obtained, along with equivalent fatigue crack growth when compared to a natural rubber/butadiene rubber black sidewall compound. Young, Kresge and Wallace (refs. 40 and 41) made cut growth/tearing energy measurements on four factory-mixed black sidewall compounds, two conventional natural rubber/butadiene rubber formulations and two compounds blended with chlorobutyl rubber. Laboratory results showed excellent tearing energies and cut growth rates Growth Rates The compounded annualized rate of growth of a company's revenues, earnings, dividends, or other figures. Notes: Remember, historically high growth rates don't always mean a high rate of growth looking into the future. for the chlorobutyl rubber-containing black sidewalls (figure 3). Tire test data showed lower cut growth rates for the chlorobutyl rubber blends. Young and Doyle (ref. 42) studied the fatigue crack growth of natural rubber, butadiene rubber, chlorobutyl rubber and bromobutyl rubber, noting that the halobutyl rubbers showed a very large reduction in crack propagation (ca. 100X) upon addition of carbon black. [Figure 3 ILLUSTRATION OMITTED] Brominated isobutylene-co-para-methylstyrene is used in non-staining passenger tire black sidewall formulations (refs. 43-48). It has been determined that at least 40 phr of BIMS rubber is needed to protect the natural rubber from ozone attack (ref. 43). The bromination and the para-methylstyrene comonomer co·mon·o·mer n. One of the compounds that constitute a copolymer. levels of the brominated isobutylene-co-para-methylstyrene rubber are important factors for ozone resistance. Flowers, Fusco and Tracey (refs. 44 and 45) reported on a brominated isobutylene-co-para-methylstyrene rubber/natural rubber/butadiene rubber compound with improved cured adhesion and tear properties by using a compatibilizer and oil blend. Tires built with black sidewalls containing BIMS rubber performed well compared to the general-purpose rubber control compound: DOT testing was comparable, high speed testing was improved, but rolling resistance was also increased. Fleet evaluations indicated that the experimental tires with BIMS sidewalls retained their black color throughout the testing period, while the chemically protected general-purpose rubber sidewall surface discolored dis·col·or v. dis·col·ored, dis·col·or·ing, dis·col·ors v.tr. To alter or spoil the color of; stain. v.intr. To become altered or spoiled in color. to a reddish-brown. McElrath and Tisler (ref. 48) studied the large-scale internal mixing of a brominated isobutylene-co-para-methylstyrene rubber/natural rubber/butadiene rubber sidewall compound. Transmission electron microscopy “TEM” redirects here. For other uses, see TEM (disambiguation). Transmission electron microscopy (TEM) is an imaging technique whereby a beam of electrons is transmitted through a specimen, then an image is formed, magnified and directed to appear either followed by image analysis was used to relate the polymer phase morphology to physical properties. They determined that the BIMS rubber phase must be highly dispersed to minimize crack growth, and a three-step remill-type mixing sequence was suitable. Use of a lower bromination level in the BIMS rubber improved crack growth resistance, but also resulted in decreased ozone resistance and adhesion to a carcass compound. However, use of a BIMS rubber having a lower bromination level in conjunction with an increased para-methylstyrene comonomer content resulted in generally improved sidewall compound properties (table 4). Tires containing BIMS elastomers having both lower bromine and higher para-methylstyrene levels in the black sidewall were built and tested (ref. 49), with those having a BIMS robber with ten weight-% para-methylstyrene performing equivalent to a NR/butadiene rubber control in the ozone wheel test. Tires with a BIMS rubber having twelve weight-% para-methylstyrene and 0.85 mole-% benzylic bromide bromide, any of a group of compounds that contain bromine and a more electropositive element or radical. Bromides are formed by the reaction of bromine or a bromide with another substance; they are widely distributed in nature. outperformed the NR/BR control in this test. All tires having BIMS elastomers in the black sidewall enhanced tire appearance.
Table 4 - BIMS elastomer black sidewall compound(a) properties
(ref. 48)
MDX EDU
93-4(b) 043(c)
Mooney Scorch @ 135% (min.
to 5 pt. rise 9.1 11.2
ODR @ 160 [degrees] C (1 [degrees] arc)
Maximum torque, dNm 23 21
Ts2, min. 4.0 4.1
T90, min. 22.3 18.3
Stress-strain
Modulus (a) 200%, MPa 3.2 2.8
Tensile strength, MPa 12.6 13.3
Elongation, % 556 618
Shore A hardness 45 45
Fatigue-to-failure (101% elongation,
100 c/min.) 307,314 594,024
DeMattia flex (pierced, 60 degree
bend, 300 c/min.)
Crack length, mm @ 4.5 kc 4.5 3.6
@ 90 kc 8.9 6.0
@ 2,200 kc 10.7 6.7
1" strip adhesion (avg. peel @
100 [degrees] C, #/in.)
to self 115 >200
to carcass 131 146
Ozone test (40 [degrees] C, 25 pphm
03, 33 days)
Static No cracks No cracks
Dynamic No cracks No cracks
Outdoor flex (27 days) 1 minor edge No cracks
Crack after 14 days
(a.) Formulation: BR, 50 phr; NR 10; BIMS elastomer, 40:N351 black, 40; oil, 12; tackifying resin, 5; Struktol, 4; SP 1068, 2; stearic acid stearic acid /ste·a·ric ac·id/ (ste-ar´ik) a saturated 18-carbon fatty acid occurring in most fats and oils, particularly of tropical plants and land animals; used pharmaceutically as a tablet and capsule lubricant and as an emulsifying , 0.5; sulfur, 0.4; zinc oxide, 0.75; Rylex 3011,0.6; MBTS MBTS 2-Mercaptobenzothiazyl Disulfide MBTS Missile Bit Test Set MBTS Missile Bench Test Set , 0.8. (b.) 7.5 wt % PMS (Pantone Matching System) A color matching system that has a unique number assigned to more than 500 different colors and shades. This standard for the printing industry has been built into many graphics and desktop publishing programs to ensure color accuracy. , 1.2 mol % BrPMS. (c.) 9.5 wt % PMS, 1.0 mol % BrPMS Mouri (ref. 50) studied non-staining black sidewall compounds and showed that a blend of brominated isobutyleneco-para-methylstyrene/natural rubber/butadiene rubber performed better than EPDM/NR/BR compounds in laboratory and tire testing. Dispersion of the polymer and fatigue to failure (cut growth) of the BIMS sidewall were superior to the EPDM compounds, even when the EPDM compound was phased mixed. Mason (ref. 51) reported the use of a blend of brominated isobutylene-co-para-methylstyrene and EPDM rubbers [NR/BR/BIMS/EPDM (40/10/30/20)] to form a non-staining tire black sidewall with improved adhesion to a carcass compound and flex resistance compared to a NR/BR/BIMS (10/50/40) control compound. Tires had improved ozone resistance on an aged ozone wheel test, and high speed and rolling resistance. White sidewall and cover strip Chlorobutyl rubber/EPDM rubber/natural rubber blends are used in tire white sidewall compounds (refs. 35 and 52-56), and in white sidewall cover strip compounds (refs. 26 and 56). The chlorobutyl rubber imparts flex resistance to the compounds. Treads The tread is the wear-resistant component of a tire which comes in contact with the road. It is designed for abrasion resistance, traction, speed, stability and casing protection. The tread rubber is compounded for wear, traction, low rolling resistance and durability (ref. 18). It is normally composed of a blend of SBR SBR - Spectral Band Replication and BR elastomers for passenger tires. Isobutylene-based elastomers have been studied in treads with blends of natural rubber, styrene-butadiene rubber and butadiene rubber (refs. 26, 34 and 57-67). Sabey and Lupton (ref. 58) measured the friction of nine tread compounds prepared with natural rubber, NR/SBR, oil-extended SBR, butadiene rubber, EPDM rubber and butyl rubber. The butyl rubber compound had the highest friction value on a number of surfaces ranging from a very smooth, very highly polished surface with a texture depth of [is less than] 0.001 inches, to rough coarse textured, polished stones with a texture depth of 0.04 inches. The skid resistance of the butyl rubber compound maximized at about 30 [degrees] C, showing a minimum at -10 [degrees] C. Cohen cohen or kohen (Hebrew: “priest”) Jewish priest descended from Zadok (a descendant of Aaron), priest at the First Temple of Jerusalem. The biblical priesthood was hereditary and male. (refs. 59 and 60) reported that copolymers of isobutylene and cyclopentadiene improved the wet skid resistance of a carbon black-filled SBR/BR tread compound. Keller (ref. 61) studied carbon black-filled chlorobutyl rubber/SBR blends, and showed that as the percentage of chlorobutyl rubber used was increased, the rebound decreased linearly and the skid resistance increased linearly. Tire testing revealed that 30 phr chlorobutyl was needed for a 5% improvement in skid resistance; however, at this level the relative treadwear rating The Treadwear Grade of a tire is the numeric portion of the Uniform Tire Quality Grade Standards (UTQG) that are printed on the sidewall of a tire. These standards were enacted by the National Highway Traffic Safety Administration (NHTSA), which is part of the United States was 4% lower than the SBR/BR control in a low severity road wear test. Increased chlorobutyl rubber use further decreased relative treadwear. Hirakawa and Ahagon (ref. 62) evaluated carbon black-filled chlorobutyl rubber/NR/BR tire treads, concluding that lower hysteresis hysteresis (hĭs'tərē`sĭs), phenomenon in which the response of a physical system to an external influence depends not only on the present magnitude of that influence but also on the previous history of the system. and equal or better wet skid resistance could be obtained by using chlorobutyl rubber. Fusco and Young (ref. 26) blended bromobutyl rubber with oil-extended SBR in carbon black-filled compounds, improving wet traction, but decreasing treadwear in tire tests (table 5). Similar results were obtained when blending bromobutyl rubber with non-oil-extended styrene-butadiene rubber (SBR 1502) (ref. 63). Wilson (ref. 1) increased compound wet traction based on laboratory dynamic properties using bromobutyl robber in blends with SBR and BR; however, abrasion loss also increased. He concluded that poor abrasion is an inherent property of butyl rubber and that tread compounds containing HIIR will, in general, have poorer wear properties than similar compounds in which the HIIR is not present (ref. 1). Table 5 - BIIR blend tread evaluation in high performance tires (ref. 26) Compound 1 2 SBR 1712 137.5 110 BIIR 2255 0 20 N110 black 85 85 Aromatic oil 17.5 25 Stearic acid 2.0 2.0 6PPD(a) 2.0 2.0 Zinc oxide 3.0 3.0 OBTS(b) 2.0 2.0 Sulfur 2.5 2.5 Mooney scorch, T10 @ 135 [degrees] C 11.8 8.4 Mooney viscosity, M L(2+8) @ 100 [degrees] C 63 77 Rheometer, 160 [degrees] C, 1 [degrees] arc MH-ML 25.3 23.9 Ts2 5.4 5.6 Tc90 11.3 12.6 Press cure 15 min. @ 160 [degrees] C Hardness, Shore A 73 72 300% modulus, MPa 11.3 11.5 Tensile strength, MPa 18.5 15.0 Elongation, % 460 380 Wet traction tire test results 20 mph, peak (index) 100 110 60 mph, peak (index) 100 113 Tire treadwear results Wear index, crown 100 75 Wear index, shoulder 100 69 Pico abrasion (mean of 4 samples) 114 106 Dynamic properties @ 25 [degrees] C 12 Hz, [+ or -] 5% strain (mean of 2 samples) G', N/[mm.sup.2] 3.72 4.02 G", N/[mm.sup.2] 1.48 1.60 Tan [Delta] 0.40 0.40 At 0 [Delta]C, 100 Hz [+ or -] 70N load (mean of 2 samples) G', N/[mm.sup.2] 16.4 22.1 G", N/[mm.sup.2] 3.43 3.83 Tan [Delta] 0.209 0.173 Compound 3 SBR 1712 110 BIIR 2255 20 N110 black 85 Aromatic oil 25 Stearic acid 2.0 6PPD(a) 2.0 Zinc oxide 3.0 OBTS(b) 1.80 Sulfur 2.3 Mooney scorch, T10 @ 135 [degrees] C 8.6 Mooney viscosity, M L(2+8) @ 100 [degrees] C 80 Rheometer, 160 [degrees] C, 1 [degrees] arc MH-ML 22.1 Ts2 6.1 Tc90 15.4 Press cure 15 min. @ 160 [degrees] C Hardness, Shore A 72 300% modulus, MPa 11.4 Tensile strength, MPa 15.3 Elongation, % 390 Wet traction tire test results 20 mph, peak (index) 111 60 mph, peak (index) 111 Tire treadwear results Wear index, crown 80 Wear index, shoulder 75 Pico abrasion (mean of 4 samples) 108 Dynamic properties @ 25 [degrees] C 12 Hz, [+ or -] 5% strain (mean of 2 samples) G', N/[mm.sup.2] 3.72 G", N/[mm.sup.2] 1.48 Tan [Delta] 0.397 At 0 [Delta]C, 100 Hz [+ or -] 70N load (mean of 2 samples) G', N/[mm.sup.2] 19.3 G", N/[mm.sup.2] 3.90 Tan [Delta] 0.202 (a.) Santoflex 13F; (b.) Santocure MOR MOR abbr. middle-of-the-road MOR adj abbr (MUS) (= middle-of-the-road) → para el gran público MOR adj abbr (Mus) (= Mroczkowski (ref. 64) studied blends of bromobutyl rubber, star-branched bromobutyl rubber and brominated isobutylene-co-para-methylstyrene in carbon black- and silica-filled SBR/BR compounds. Increased tangent tangent, in mathematics. 1 In geometry, the tangent to a circle or sphere is a straight line that intersects the circle or sphere in one and only one point. delta values at low temperatures (-30 to +10 [degrees] C) and decreased tangent delta values at higher temperatures ([is greater than] 30 [degrees] C) were obtained compared to a carbon black-filled NR/BR/SBR tire tread composition (figure 4). Laboratory abrasion resistance was comparable. Costemalle, Hous and McElrath (ref. 34) reported that use of bromobutyl rubber or brominated isobutyleneco-para-methylstyrene increased the tangent delta values at 0 [degrees] C of carbon black-filled emulsion-(SBR 1502) and solution-SBR (sSBR 1216)/BR compounds. [Figure 4 ILLUSTRATION OMITTED] Zanzig and coworkers (ref. 65) evaluated brominated isobutylene-co-para-methylstyrene in blends with isoprenebutadiene rubber, butadiene rubber, natural rubber with and without styrene-butadiene rubber in silane-coupled silica-filled compounds, and found increased tangent delta values at 0 [degrees] C when using BIMS. Rogers (ref. 66) reported that use of brominated isobutylene-co-para-methylstyrene and silane-coupled silica-filled in butadiene rubber/styrene-butadiene rubber compounds afforded increased tangent delta values at 0 [degrees] C and decreased tangent delta values at 60 [degrees] C in laboratory tests, with only slight reductions in treadwear based on tire tests using sectional retreads (figure 5). Hojo (ref. 67) used a hydrazide hy·dra·zide n. An acyl derivative of hydrazine. hydrazide A compound formed by combining hydrazine with an acyl compound. Hydrazides are important in the manufacture of certain medicines. compound and brominated isobutylene-co-para-methyl-styrene to lower the heat generation and improve the wet gripping property of a carbon black and silane-coupled silica-filled natural rubber compound. [Figure 5 ILLUSTRATION OMITTED] Automotive applications Hose Hose for automotive applications requires an elastomer that is resistant to the material it is transporting, low permeability, low compression set and resistance to the increasing underhood temperatures seen in today's automobiles. Also, there is increasing focus on noise, vibration and harshness (NVH NVH Noise, Vibration and Harshness NVH Nahverkehr Hohenlohekreis (German) NVH Noise Vibration and Harshness ), and therefore, a material that can provide damping damping In physics, the restraint of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipating energy. Unless a child keeps pumping a swing, the back-and-forth motion decreases; damping by the air's friction opposes the to minimize vibration transmission is desirable. Isobutylene-based polymers satisfy all of these characteristics and hence are used commercially in this application. An important application of isobutylene-based polymers in automotive hose is in air-conditioning hose. Their use in some fuel line hose, as well as brake line hose, has been reported. Air conditioning air conditioning, mechanical process for controlling the humidity, temperature, cleanliness, and circulation of air in buildings and rooms. Indoor air is conditioned and regulated to maintain the temperature-humidity ratio that is most comfortable and healthful. hose requires a material with good barrier properties to minimize refrigerant re·frig·er·ant adj. 1. Cooling or freezing; refrigerating. 2. Reducing fever. n. 1. A substance, such as air, ammonia, water, or carbon dioxide, used to provide cooling either as the working substance of loss and reduce moisture ingression in·gress n. 1. also in·gres·sion A going in or entering. 2. Right or permission to enter. 3. A means or place of entering. . It requires good compression set to help ensure coupling integrity. Also, resistance to high temperatures is required. Damping of compressor compressor, machine that decreases the volume of air or other gas by the application of pressure. Compressor types range from the simple hand pump and the piston-equipped compressor used to inflate tires to machines that use a rotating, bladed element to achieve vibration and noise is also desirable. Air conditioning hose is typically a composite construction Composite construction is a generic term to describe any building construction involving multiple dissimilar materials. It is not to be confused with the Composite order which is a specific order of classical architecture that combines elements of the Ionic and Corinthian orders. , made of layers of rubber and rein forcing yam. In some constructions, a layer of thermoplastic resin Noun 1. thermoplastic resin - a material that softens when heated and hardens again when cooled thermoplastic plastic - generic name for certain synthetic or semisynthetic materials that can be molded or extruded into objects or films or filaments or used is as a barrier to refrigerant loss; typically, this thermoplastic resin is a polyamide polyamide material used in the creation of nonabsorbable, synthetic, nylon sutures. (ref. 68). Halobutyl rubber is typically used in automotive air conditioning hose cover largely due to its barrier properties and its resistance to moisture ingression. Pilkington, Cole and Schisler (ref. 69) reported a chlorobutyl rubber compound used as a cover for an air conditioning hose. Use of a chlorobutyl rubber cover provided better resistance to moisture ingression than an EPDM cover, and also was compatible with operating temperatures up to 120 [degrees] C. Various techniques have been described that improve the adhesion of butyl polymer compounds to various substrates, including polyester, nylon and other materials. Keller and Kuhnhein (ref. 70) show how the use of a blend of a functionalized ethylene ethylene (ĕth`əlēn') or ethene (ĕth`ēn), H2C=CH2, a gaseous unsaturated hydrocarbon. It is the simplest alkene. polymer with butyl or halobutyl rubber can improve the adhesion to polyester yam typically used as a reinforcing material. The ethylene polymer is functionalized with methyl acrylate Methyl acrylate is a volatile alpha beta unsubstituted methyl ester used in the preparation of Polyamidoamine (PAMAM) dendrimers typically by michael addition with a primary amine. Methyl acrylate is a contact allergen present in nail lacquer. and acrylic acid acrylic acid /acryl·ic ac·id/ a readily polymerizing liquid used as a monomer for acrylic polymers. . Shiota and Kitani (ref. 71) report a process for the manufacture of a flexible hose that is suited for use as an automotive air conditioning hose where a butyl rubber and halobutyl rubber blend is used as the intermediate layer between the nylon-based innermost in·ner·most adj. 1. Situated or occurring farthest within: the innermost chamber. 2. Most intimate: one's innermost feelings. n. layer and the cover. The need for an adhesive is obviated by the use of the butyl/halobutyl recipe. Fusco and Kruse (ref. 72) investigated the aging properties of brominated isobutylene-para-methylstyrene (BIMS) and they report improved aging properties over halobutyl and comparable to peroxide cured EPDM. The aging conditions used were one week at 170 [degrees] C. This increased heat resistance makes them attractive for use in automotive hose applications. Costemalle, et. al. (ref. 73) disclose the use of a compound containing BIMS for use in a hose composition. An example which shows the improved physical property retention is shown in table 6. Table 6-heat resistant BIMS compounds (ref. 73) Polymer BIMS([dagger]) N326 30 N770 30 Siloxane treated clay 20 ASTM type 104B oil 15 Fatty acid mixture 3 Low molecular weight polyethylene 4 Stearic acid 2 Zinc oxide 0.5 MBTS TMTDS DPTHS 1 Cured physical properties, cured 20' @ 160 [degrees] C Hardness, Shore A 55 100% modulus, MPa 1.6 Tensile strength, MPa 12.7 Elongation, % 570 Aged physical properties, aged 168 hours @ 150 [degrees] C Hardness, Shore A 65 100% modulus, MPa 2.8 Tensile strength, MPa 10.6 Elongation, % 350 Polymer BIMS([double dagger]) N326 30 N770 3O Siloxane treated clay 20 ASTM type 104B oil 15 Fatty acid mixture 3 Low molecular weight polyethylene 4 Stearic acid 2 Zinc oxide 0.5 MBTS TMTDS DPTHS 1 Cured physical properties, cured 20' @ 160 [degrees] C Hardness, Shore A 61 100% modulus, MPa 2.3 Tensile strength, MPa 11.4 Elongation, % 440 Aged physical properties, aged 168 hours @ 150 [degrees] C Hardness, Shore A 73 100% modulus, MPa 4.4 Tensile strength, MPa 10.6 Elongation, % 240 Polymer BIIR(#) N326 30 N770 30 Siloxane treated clay 20 ASTM type 104B oil 15 Fatty acid mixture 3 Low molecular weight polyethylene 4 Stearic acid 2 Zinc oxide 5 MBTS 2 TMTDS 1 DPTHS Cured physical properties, cured 20' @ 160 [degrees] C Hardness, Shore A 57 100% modulus, MPa 1.0 Tensile strength, MPa 10.3 Elongation, % 780 Aged physical properties, aged 168 hours @ 150 [degrees] C Hardness, Shore A 69 100% modulus, MPa 2.1 Tensile strength, MPa 4.5 Elongation, % 330 ([dagger]) 5.0 wt% para-methylstyrene, 0.5 mol% benzyllic bromine; from Exxon Chemical Company. ([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) 10.0 wt% para-methylstyrene, 0.8 mol% benzyllic bromine; from Exxon Chemical Company. (#) Exxon Bromobutyl grade 2233, from Exxon Chemical Company. McElrath and Measmer (refs. 74 and 75) studied heat resistant BIMS compounds, for use in automotive hoses. The use of glycols and hydrotalcite in conjunction with a zinc thiocarbamate accelerator was shown to improve the heat aging properties of BIMS compounds. They reported good physical property retention after aging at 175 [degrees] C, as well as good compression set (ref. 74). Results are shown in table 7. The effects of different compounding additives on reversion reversion: see atavism. and heat aging were also evaluated. Stearic acid is shown to improve the scorch/cure rate balance, as well as improve the heat aging properties (ref. 75). Also, BIMS compounds that use accelerators without zinc in the structure have more scorch safety than those with zinc, yet still retain good aging properties (ref. 75).
Table 7-effect of glycol and hydrotalcite on heat aging of
BIMS compounds
Formulation PHR
BIMS([dagger]) 100
N330 55
Paraffinic oil 5
Polyethylene wax 4
Stearic acid 2
Zinc oxide 1
Zinc Diethyldithiocarbamate 1
Triethylene glycol 2
Hydrotalcite 2
Aging conditions,
(Hours/temperature, [degrees] C)
Properties Initial 22/150 70/150
Tensile strength, MPa 14.5 13.4 13.8
Elongation, % 229 216 211
100% modulus, MPa 4.2 4.1 4.6
Hardness, Shore A 60 60 64
Properties 170/150 96/175 70/200
Tensile strength, MPa 13.1 12.5 6.9
Elongation, % 161 162 101
100% modulus, MPa 6.0 6.0 6.8
Hardness, Shore A 73 69 67
([dagger]) BIMS - Exxpro MDX (MultiDimensional EXpressions) A multidimensional query language. MDX uses syntax similar to SQL, but whereas SQL is used to query relational tables, MDX is used to query multidimensional cubes (OLAP databases). See SQL and OLAP. 90-10 by Exxon Chemical Company Isobutylene-based polymers are also used in automotive hose applications other than air conditioning. Stefano and Arvada (ref. 76) detail the use of a halobutyl interlayer Noun 1. interlayer - a layer placed between other layers layer, bed - single thickness of usually some homogeneous substance; "slices of hard-boiled egg on a bed of spinach" in a hose that is especially suited for automotive coolant systems. The halobutyl interlayer is used to bond dissimilar rubbers that are used in the tube and cover. The construction with the halobutyl rubber interlayer had lower coolant coolant (kōō´l  nt),n loss than those without. Trexler (ref. 77) reported on bromobutyl compounds for use in brake hose applications. Of several materials tested, bromobutyl rubber provided the most resistance to Delco Supremen II brake fluid brake fluid n → líquido de frenos brake fluid n → Bremsflüssigkeit f , and was also impermeable to the fluid. A bromobutyl compound is reported by Dunn (ref. 68) that has good resistance to alternate fuels such as methanol methanol, methyl alcohol, or wood alcohol, CH3OH, a colorless, flammable liquid that is miscible with water in all proportions. Methanol is a monohydric alcohol. It melts at −97. and a M85 (85:15 methanol:gasoline blend). Data are shown in table 8 that compare the utility of a bromobutyl compound versus a nitrile nitrile: see rubber. compound in hose for this application. The bromobutyl has better retention of physical properties and lower permeabilty than the nitrile control compound. Table 8-comparison of bromobutyl and nitrile compound in alternate fuels (ref. 68) Bromobutyl(dagger]) 100 NBR([double dagger]) 100 Stearic acid 1 1 N550 70 N762 75 Atomite 30 Magnesium oxide 0.3 DOP 5 MBTS 1 Zinc oxide 3 5 Sulfur 1.25 TMTD 0.4 TMTM 0.5 Physical properties, cured 10' @ 166 [degrees] C Hardness, Shore A 75 68 100% modulus, MPa 2.9 3.4 300% modulus, MPa 9.0 15.4 Tensile, MPa 9.5 19.5 Elongation, % 320 440 Aged in methanol, 168 hrs. @ RT-change Hardness, )pts.) -2 -8 Tensile strength, (%) +4 -22 Elongation, (%) +5 -31 Volume (%) -2 +11 Aged in M85, 168 hrs. @ RT- change Hardness, (pts.) -26 -16 Tensile strength, (%) -21 -37 Elongation, (%) -22 -44 Volume (%) +29 +24 Aged in Fuel C, 168 hrs. @ RT- change Hardness, (pts.) -43 -26 Tensile strength, (%) -63 -56 Elongation, (%) -67 -59 Volume (%) +220 +51 Permeability (weight loss in grams after 14 days) Methanol 0.2 1.48 M*% 0.42 4.20 ([dagger]) Bromobutyl - Polysar Bromobutyl 2030 ([double dagger]) NBR NBR Number NBR Nightly Business Report (PBS show) NBR National Business Review (New Zealand weekly business newspaper) NBR National Bureau of Asian Research NBR National Board of Review - Polysar Krynac 3450 Automotive dynamic parts Isobutylene-based polymers are used for various types of automotive mounts because of their ability to damp vibrations from the road or engine. Warley has published data that compare the dynamic properties of butyl rubber versus those of natural rubber (ref. 78). Reed and Warley show that for equal dynamic spring rate to static spring rate ratios ([k.sub.d]/[k.sub.s]), the butyl compound will exhibit higher damping or hysteresis (ref. 79). Butyl and halobutyl rubber is used in automotive mounting applications where a degree of damping is required. Some uses include body mounts and in medium damping engine mounts (ref. 80). Exhaust hanger straps also use halobutyl due to its heat resistance. Dunn has published work on a bromobutyl compound cured with zinc oxide and diamine di·am·ine n. Any of various chemical compounds containing two amino groups, especially hydrazine. Noun 1. diamine - any organic compound containing two amino groups antioxidants. Martin discloses a resilient engine mount in which a high damping material is used in conjunction with a resilient material to resist transmission of vibrations from the engine at both high and low amplitude vibrations. The high damping material is preferably an isobutylene-based rubber (ref. 81). Tabar and Kilgoar (ref. 82) disclose a soft, fatigue resistant compound that uses a blend of natural rubber and bromobutyl as its base. Also, the compound uses uncured polyisobutylene as an additive to improve its durability. Blends of NR/BIIR showed greater fatigue resistance than the natural rubber compound. The addition of polyisobutylene to a natural rubber and bromobutyl rubber blend also gave improved fatigue resistance. McElrath and Measmer (refs. 83 and 84) report on the use of natural rubber and BIMS blends to achieve improved heat aging over conventional natural rubber compounds. It is shown that the addition of BIMS increases the damping at low temperatures, but at room temperature, the effect is slight, and at elevated temperatures, there is no increase. Also, blends of BIMS and natural rubber provide more stable dynamic properties after heat aging than the natural rubber control, and they also delay the onset of stiffening stiff·en tr. & intr.v. stiff·ened, stiff·en·ing, stiff·ens To make or become stiff or stiffer. stiff . Heat aging properties are also improved. Mouri (ref. 85) has developed an application that makes use of butyl rubber's damping properties. In it, an elastomeric coupling, made of butyl rubber blended with natural rubber, is used to transmit steering wheel input to the tires. It is said to improve the steering response and give improved driving feel. Summary Isobutylene-based elastomers have a unique combination of material properties that are exploited for use in automotive applications. Some of these properties include low permeability to gases and liquids, high damping and chemical resistance. Halogenated isobutylene-based-elastomers have these same properties, and also high heat resistance. Brominated isobutylene-co-para-methylstyrene have all of these properties, but with even greater heat resistance and inherent ozone resistance. Tire inner liners make use of halobutyl rubber's barrier properties and its ability to adhere to adhere to verb 1. follow, keep, maintain, respect, observe, be true, fulfil, obey, heed, keep to, abide by, be loyal, mind, be constant, be faithful 2. diene-rubber based carcasses. BIMS is used in blends with other elastomers in tire black sidewalls to eliminate the need for chemical protectants, which thereby eliminates the bloom of these protectants and the staining of the sidewall. Blends containing chlorobutyl rubber are also used in white sidewall compounds and white sidewall coverstrips due to their good flex properties. The use of blends of BIMS with other rubbers are being evaluated in tire treads to improve traction without an increase in rolling resistance. Other automotive applications include hose and dynamic parts. Hose applications make use of halobutyl rubber's low gas and liquid permeability, and good heat resistance and compression set. BIMS has shown promise in hose applications due to its further improved heat aging properties. Body mounts use butyl rubber because of its high damping. Blends of BIMS and natural rubber are being evaluated as a means of improving the heat resistance of engine mounts. References (1.) G.J. Wilson, "Butyl and the halobutyls," paper presented to Educational Symposium at a meeting of the Rubber Division, American Chemical Society The American Chemical Society (ACS) is a learned society (professional association) based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has over 160,000 members at all degree-levels and in , Houston, TX, Oct. 24, 1983. (2.) E.N. Kresge, R.H. Schatz and H-C. Wang, "Isobutylene polymers" in "Encyclopedia of Polymer Science Polymer science or macromolecular science is the subfield of materials science concerned with polymers, primarily synthetic polymers such as plastics. The field of polymer science includes researchers in multiple disciplines including chemistry, physics, and engineering. and Engineering," Second Edition, J.I. Kroschwitz, editor, John Wiley John Wiley may refer to:
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of , 1987, v. 8, p. 423. (3.) J.V. Fusco and P. Hous, "Butyl and halobutyl rubbers" in "The Vanderbilt Rubber Handbook," R.F. Ohm, editor, R.T. Vanderbilt Company, Inc., Norwalk, 1990, p. 92. (4.) E.N. Kresge and H-C. Wang, "Butyl rubber" in "Kirk-Othmer Encyclopedia of Chemical Technology," Fourth Edition, M. Howe-Grant, editor, John Wiley & Sons, New York, 1993, v. 8, p. 934. (5.) D. Kruse and J.V. Fusco, Rubber & Plastics News 1993 Technical Yearbook, May, 1994, p. 10. (6.) H.Y. Che and J.E. Field, J. Polym. Sci., Part B, 5, 501 (1957). (7.) A. Van Tongerloo and R. Vukov, Proceedings of the International Rubber Conference, Venice, 1979, p. 70. (8.) R. Vukov, Rubber Chem. Technol. 57, 275 (1984). (9.) J.D. Ferry, "Viscoelastic Adj. 1. viscoelastic - having viscous as well as elastic properties natural philosophy, physics - the science of matter and energy and their interactions; "his favorite subject was physics" properties of polymers," Third Edition, John Wiley & Sons, Inc., New York, 1980. (10.) V. Stannett in "Diffusion in polymers," J. Crank and G.S. Park, editors, Academic Press, Inc., Orlando, 1968, Chapter 2. (11.) A.Y. Coran in Science and Technology of Rubber, F.R. Eirich, editor, Academic Press, Inc., Orlando, 1978. (12.) D.S D.S Drainage Structure (flood protection) . Breslow, W.D. Willis and L.O. Amberg, Rubber Chem. Technol. 43, 605 (1970). (13.) R.L. Zapp, R.A. Decker, M.S. Dyroll and H.A. Rayner, J. Polm. Sci. 6, 31 (1951). (14.) R. Vukov, Proceedings of the International Rubber Conference, Venice, 1979, p. 284. (15.) R. Bielski, J.M.J. Frechet, J.V. Fusco, K.W. Powers and H-C. Wang, J. Polym. Sci., Part A., 31, 755 (1993). (16.) J.M.J. Frechet, R. Bielski, J.V. Fusco, K.W. Powers and H-C. Wang, Rubber Chem. Technol., 66, 98 (1993). (17.) I. Duvdevani and N.F. Newman, Rubber World, 216 (5), 28 (1997). (18.) R.S. Bhakuni, S.K. Mowdood, W.H. Waddell, I.S. Rai and D.L. Knight, "Tires" in "Encyclopedia of Polymer Science and Engineering," Second Edition, J.I. Kroschwitz, Editor, John Wiley & Sons, New York, 1989, v. 16, p. 834. (19.) K. Voigtlander, Rubber South Africa South Africa, Afrikaans Suid-Afrika, officially Republic of South Africa, republic (2005 est. pop. 44,344,000), 471,442 sq mi (1,221,037 sq km), S Africa. , 10 (6), 10 (1995). (20.) W. Hopkins, R.H. Jones and J. Walker, "Bromobutyl and chlorobutyl. A comparison of their chemistry, properties and uses," paper 16A10 presented at IRC (Internet Relay Chat) Computer conferencing on the Internet. There are hundreds of IRC channels on numerous subjects that are hosted on IRC servers around the world. After joining a channel, your messages are broadcast to everyone listening to that channel. '85 Kyoto; International Rubber Conference Proceedings, Oct. 15-18, 1985, p. 205. (21.) N.E. Odam, J. Industrial Res. Inst., Aug., 1971, p. 140. (22.) B. Topcik, Atti Congr. Int. Mater. Plast. Elastomeriche, Oct. 7-10, 1968, p. 233. (23.) C.W. von Hellens, "Inner liners for high performance tires," paper no. 50 presented at a meeting of the Rubber Division, American Chemical Society, Indianapolis, IN, May 10, 1984. (24.) M. Ogawa and Y. Hirata (to Bridgestone Corp.), U.S. 4,396,051 (Aug. 2, 1983). (25.) C.L. Morehart and F.J. Ravagnani (to Bridgestone Corp.), European 0 604 834 A1 (Dec. 15, 1993). (26.) J.V. Fusco and D.G. Young, "Isobutylene-based polymers in tires - status and future trends," paper no. 8 presented at a meeting of the Rubber Division, American Chemical Society, Washington, D.C., October 9-12, 1990. (27.) K.J. Kumbhani, J.J. Sendorek and H. Tang, J. Elastomers Plast., 24, 262 (1992). (28.) B.J. Costemalle and J.V. Fusco (to Exxon Chemical), U.S. 5,386,864 (Feb. 7, 1995). (29.) P.H. Sandstrom and R.B. Roennau (to The Goodyear Tire & Rubber Co.), European 0 682 075 A1 (Apr. 20, 1995). (30.) S. Katsuki, K. Yamakawa, J. Watanabe and H. Kaido (to Yokohama Rubber Co.), European 0 706 878 A2 (Sept. 12, 1995). (31.) D. Novakoski, R. Juengel and S. Laube, Rubber & Plastics News, Sept. 9, 1996, p. 39. (32.) I. Duvdevani, L. Gursky and I.L. Gardner, "Star branched butyl - a novel butyl rubber for improved process-ability. II. Properties and applications," paper no. 22 presented at a meeting of the Rubber Division, American Chemical Society, Mexico City Mexico City Spanish Ciudad de México City (pop., 2000: city, 8,605,239; 2003 metro. area est., 18,660,000), capital of Mexico. Located at an elevation of 7,350 ft (2,240 m), it is officially coterminous with the Federal District, which occupies 571 sq mi , Mexico, May 9-12, 1989. (33.) B. Costemalle, J.V. Fusco and D.F. Kruse, J. Elastomers Plast., 27, 39 (1995). (34.) B. Costemalle, P. Hous and K.O. McElrath, "Exxpro polymers," paper no. G11 presented at Rubbercon '95, Gothenburg, Sweden, May 9-12, 1995. (35.) W.H. Waddell, R.S. Bhakuni, W.W. Barbin and P.H. Sandstrom, "Pneumatic tire Noun 1. pneumatic tire - a tire made of reinforced rubber and filled with compressed air; used on motor vehicles and bicycles etc pneumatic tyre bicycle wheel - the wheel of a bicycle compounding" in "The Vanderbilt Rubber Handbook," R.F. Ohm, editor, R.T. Vanderbilt Company, Inc., Norwalk, CT, 1990, p. 595. (36.) W.H. Waddell, "Tire black sidewall surface discoloration dis·col·or·a·tion n. 1. a. The act of discoloring. b. The condition of being discolored. 2. A discolored spot, smudge, or area; a stain. Noun 1. : A review," paper no. 62 presented at a meeting of the Rubber Division, American Chemical Society, Cleveland, OH, October 21-24, 1997. (37.) L.T. Ladocsi and D.G. Young (to Esso Research & Engineering), U.S. 3,630,974 (Dec. 28, 1971). (38.) H.R. Waser (to The Goodyear Tire & Rubber Co.), U.S. 3,830,274 (Aug. 20, 1974). (39.) L. Gursky (to Exxon Research & Engineering), U.S. 4,224,196 (Sept. 23, 1980). (40.) D.G. Young, E.N. Kresge and A.J. Wallace, "Fundamental flex fatigue studies of tire sidewall materials, "paper no. 64 presented at a meeting of the Rubber Division, American Chemical Society, Cleveland, Ohio "Cleveland" redirects here. For the Cleveland metropolitan area, see . For other uses, see Cleveland (disambiguation). Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County, the most populous county in the state. , October 16, 1981. (41.) D.G. Young, E.N. Kresge and A.J. Wallace, Rubber Chem. Technol. 55, 428 (1982). (42.) D.G. Young and M.J. Doyle, "Fatigue crack propagation research of halobutyl elastomer blends for tire sidewalls," International Rubber Conference Proceedings, Kyoto, Japan, October 15-18, 1985, p. 469. (43.) D.D. Flowers, J.V. Fusco, L.J. Gursky and D.G. Young, Rubber World 204 (5), 26 (1991). (44.) D.D. Flowers, J.V. Fusco and D.S. Tracey, "Advancements in new tire sidewalls with a new isobutylene based copolymer," paper no. 50 presented at a meeting of the Rubber Division, American Chemical Society, Orlando, FL, October 26-29, 1993. (45.) D.D. Flowers, J.V. Fusco and D.S. Tracey, Rubber World 209 (6), 32 (1994). (46.) B. Costemalle, D.D. Flowers, J.V. Fusco and M. Steurs (to Exxon Chemical Patents, Inc.), U.S. 5,376,438 (Dec. 27, 1994). (47.) L.J. Gursky, J.V. Fusco and D.D. Flowers (to Exxon Chemical Patents, Inc.), U.S. 5,532,312 (July 2, 1996). (48.) K.O. McElrath and A.L. Tisler, "Improved elastomer blend for tire sidewalls," paper no. 6 presented at a meeting of the Rubber Division, American Chemical Society, Anaheim, CA, May 6-9, 1997. (49.) A.L. Tisler, K.O. McElrath, D.S. Tracey and M.F. Tse, "New grades of BIMS non-stain tire sidewalls, "paper no. 66 presented at a meeting of the Rubber Division, American Chemical Society, Cleveland, OH, Oct. 21-24, 1997. (50.) H. Mouri, "Improvement of tire sidewall appearance using highly saturated polymers," paper no. 65 presented at a meeting of the Rubber Division, American Chemical Society, Cleveland, OH, Oct. 21-24, 1997. (51.) R.A. Mason (to The Goodyear Tire & Rubber Co.), European 0 801 106 A1 (Apr. 3, 1997). (52.) A.E Crepeau, J. Elastomers Plast., 9, 349 (1977). (53.) D.E. Wingrove, "Natural rubber-chloroprene-ethylene propylene propylene /pro·pyl·ene/ (pro´pi-len) a gaseous hydrocarbon, CH3CHdbondCH2. propylene glycol a colorless viscous liquid used as a humectant and solvent in pharmaceutical preparations. diene blends in white sidewall compounds, "paper no. 7 presented at a meeting of the Rubber Division, American Chemical Society, Chicago, IL, Oct. 5-8, 1982. (54.) A.E. Zelichenik, L.T. Goncharova, T.N. Vinogradova, A. G. Shvarts and N.N. Kozhemyakina, Int. Polym. Sci. Technol., 16, T/77 (1989). (55.) P.I. Prescott and C.A. Rice (to E.C.C. America), U.S. 4,810,578 (Mar. 7, 1989). (56.) R.B. Wilson (to The General Tire The General Tire and Rubber Company is an American manufacturer of tires for motor vehicles. General Tire was founded in 1915 in Akron, Ohio by William F. O'Neil. In 1943 General Tire branched out from its core business by purchasing the Yankee Network and the radio stations & Rubber Co.), U.S. 3,508,595 (Apr. 28, 1970). (57.) D.G. Young (to Exxon Chemical Patents), U.S. 5,063,268 (Nov. 5, 1991). (58.) B.A. Sabey and G.N. Lupton, Rubber Chem. Technol. 37, 878(1964). (59.) H.L. Cohen (to Exxon Research and Engineering), U.S. 3,919,130 (Nov. 11, 1975). (60.) H.L. Cohen (to Exxon Research and Engineering), U.S. 4,012,344 (Mar. 15, 1977). (61.) R.C. Keller, Tire Sci. Technol., 1, 190 (1973). (62.) H. Hirakawa and A. Ahagon, Tire Sci., Tech., 10, 16 (1982). (63.) G.R. Smith, P.K. Agarwal, B. Costemalle and D.S. Forbes, Rubbercon '88, paper no. 20. (64.) T.S Mroczkowski (to Pirelli Armstrong Tire Corp.), U.S. 5,063,268 (Nov. 10, 1992). (65.) D.J. Zanzig, P.H. Sandstrom, J.J.A. Verthe and M.J. Crawford (to the Goodyear Tire & Rubber Co.), European 0 682 071 A1 (Nov. 15, 1995). (66.) J.E. Rogers, ITEC ITEC Instituto de Tecnologia em Informática e Informação do Estado de Alagoas ITEC International Therapy Examination Council (UK) ITEC Internet Technology ITEC Institute for Tropical Ecology and Conservation ITEC Instructional Technologies '96 Select, 1, 125 (1997). (67.) M. Hojo (to Bridgestone Corp.) U.S. 5,705,549 (Jan. 6, 1998). (68.) J.R. Dunn, Elastomerics, January, 1991, p. 15. (69.) M.V. Pilkington, R.W. Cole and R.C. Schisler (to Goodyear Tire & Rubber Co.), U.S. 4,633,912 (Jan. 6, 1987). (70.) R.C. Keller and M.R. Kuhnhein (to Exxon Chemical Patents Inc.), U.S. 5,021,509 (Jun. 4, 1991). (71.) A. Shiota and K. Kitani (to Nichirin Co., Ltd), U.S. 5,488,974 (Feb. 6, 1996). (72.) D.F. Kruse and J.V. Fusco, Rubber & Plastics News, February 1, 1993, p. 15. (73.) B.J. Costemalle, R.C. Keller, D.F. Kruse, J.V. Fusco and M.A. Steurs (to Exxon Chemical Patents, Inc.), U.S. 5,246,778 (Sept. 21, 1993). (74.) K.O. McElrath and M.B. Measmer, Rubber & Plastics News, January 29, 1996. (75.) K.O. McElrath and M.B. Measmer, "Reversion resistant Exxpro elastomer compounds," paper no. 5 presented at a meeting of the Rubber Division, American Chemical Society, Louisville, KY, October 8-11, 1996. (76.) G.E. Stefano and D.N. Tally (to The Gates Rubber Company), U.S. 4,158,033 (June 12, 1979). (77.) H.E. Trexler, "The development of automotive brake hose elastomer compositions," paper presented at a meeting of the Rubber Division, American Chemical Society, Denver, CO, October 23-26, 1984. (78.) R.L. Warley, "Dynamic properties of elastomers as related to vibration isolator performance," Rubber World 213, No. 6, 33-39 (March 1996). (79.) T. Reed and R. Warley, "Carbon black's effects on vibration isolation Vibration isolation is the process of isolating an object, such as a piece of equipment, from the source of vibrations. Despite construction distinctions the essence of all vibration isolation systems are similar. ," paper no. 29 presented at a meeting of the Rubber Division, American Chemical Society, Anaheim, CA, May 6-9, 1997. (80.) J.R. Dunn, Elastomerics, February, 1989, p. 28. (81.) R.D. Martin (to The Standard Products Company), U.S. 4,489,921 (Dec. 25, 1984). (82.) R.J. Tabar and P.C. Killgoar (to Ford Motor Company), U.S. 4,419,480 (Dec. 6, 1983). (83.) K.O. McElrath, M.B. Measmer and S. Yamashita, "Dynamic properties of elastomer blends, "paper no. 44 presented at a meeting of the Rubber Division, American Chemical Society, Montreal, Canada, May 4-8, 1996. (84.) M.B. Measmer and K.O. McElrath, "Elastomer blend approach to extend heat life of natural rubber based engine mounts," Rubber World, 217, No. 5, 41-45 (Feb. 1998) (85.) H. Mouri (to Nissan Motor Co. Ltd.), U.S. 5,690,361 (Nov. 25, 1997). John E. Rogers and Walter H. Waddell |
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