Cost-effective modifiers for the preparation of BIIR based tire tread formulations.
The research efforts directed at developing tire tread formulations typically focus on the optimization of several performance-related parameters. Among these, 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. , wet traction and wear resistance are considered to be the most important. The positive influence of these three properties governs the selection of the constituent elastomers, fillers and modifiers. For example, butadiene butadiene (byt'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 (BR) is well known to impart excellent wear resistance to the tread formulation. However, as indicated by the low value of tan [delta] at 0[degrees]C depicted in figure 1, BR does very little to improve wet traction performance. For this reason, (S)SBR SBR - Spectral Band Replication type elastomers are typically employed in tread compounds. The broad mechanical glass transition ([T.sub.g]) centered around -20[degrees]C is an indirect measure of the loss factor associated with deformation frequencies characteristic of those occurring during a wet skid. A paradigmatic See paradigm. advancement in tread technology came with the introduction of the green tire (refs. 1 and 2). In this technology, conventional carbon black (CB) fillers were replaced with silica in combination with silica-modifiers such as TESPT (Si69). The resulting BR/VSBR tread formulations saw an improvement in the predicted wet traction (i.e., more pronounced mechanical [T.sub.g], higher value of tan [delta] @ 0[degrees]C) and a significant reduction in rolling resistance.
[FIGURE 1 OMITTED]
For several decades, it has been well known that the incorporation of halobutyl elastomers (CIIR CIIR Catholic Institute for International Relations
CIIR Center for Intelligent Information Retrieval
CIIR counterintelligence information report (US DoD)
CIIR Canadian International Information Resource or BIIR BIIR Baylor Institute for Immunology Research (Dallas, Texas)
BIIR Basic Imagery Interpretation Report
BIIR Brominated Isobutylene-Isoprene Rubber ) into tire tread formulations results in a significant improvement in wet traction. However, as a result of the low levels of unsaturation un·sat·u·rat·ed
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. present in these materials (ca. 1.5 mol % unsaturation in HIIR; c.f. ca. 50 mol % in BR), the level of van der Waals interaction with CB is minimal. Consequently, the 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. resistance of tread compounds utilizing HIIR is poor. This, in turn, precluded the use of HIIR in any practical tread application. The intrinsic interaction of HIIR with siliceous siliceous
relating to or made of silica or a silicate. fillers is also poor. Specifically, the low energy, hydrophobic hydrophobic /hy·dro·pho·bic/ (-fo´bik)
1. pertaining to hydrophobia (rabies).
2. not readily absorbing water, or being adversely affected by water.
3. , HIIR 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. is incompatible with the high energy, hydrophilic hydrophilic /hy·dro·phil·ic/ (-fil´ik) readily absorbing moisture; hygroscopic; having strongly polar groups that readily interact with water.
adj. , silica surface.
Building on the seminal results of Degussa and Michelin, several groups have shown that it is possible to compatabilize HIIR type elastomers and silica by using the same small molecule amphiphiles (e.g., TESPT) currently used in conventional silica tread technology (refs. 3-7). In the case of BIIR, the oligosulfido moiety moiety: see clan. present in TESPT reacts quite readily with the allylic al·lyl
The univalent, unsaturated organic radical C3H5.
[Latin allium, garlic + -yl (so called because it was first obtained from garlic). bromides of BIIR (figure 2). A hydrolysis hydrolysis (hīdrŏl`ĭsĭs), chemical reaction of a compound with water, usually resulting in the formation of one or more new compounds. reaction between the silylether groups of the TESPT fragment and the silica surface silanol groups results in the formation of a stable siloxane siloxane /si·lox·ane/ (si-lok´san) any of various compounds based on a substituted backbone of alternating silica and oxygen molecules; in polymeric form they are polysiloxanes, and when the side chain substituents are organic radicals, linkage. Overall, these coupling reactions result in the formation of a chemical link between the elastomer and filler surface (figure 3).
[FIGURES 2-3 OMITTED]
In essence, TESPT is acting as a small molecule amphiphile that can effectively temper the surface energy differences that exist between BIIR and silica. In addition, this species possesses surface specific functional groups which, when reacted, result in the formation of a covalent co·va·lent
Of or relating to a chemical bond characterized by one or more pairs of shared electrons. linkage between these surfaces. With this compatibilization model in mind, we have recently identified aminoalcohols as effective
compatibilizers for BIIR/silica compounds.
Aminoalcohols are an extremely versatile class of compounds which find application in coatings, emulsion emulsion: see colloid.
Mixture of two or more liquids in which one is dispersed in the other as microscopic or ultramicroscopic droplets (see colloid). Emulsions are stabilized by agents (emulsifiers) that (e.g. stabilization, water treatment and chemical synthesis In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions. (ref. 8). These compounds are marked by the presence of at least one neutral amino group amino group, in chemistry, functional group that consists of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of these three. An organic compound that contains an amino group is called an
amine. and one hydroxyl group hydroxyl group (hīdrŏk`sĭl), in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by a single bond to an alkyl group or aryl group. . As it is well known that BIIR reacts readily with neutral amines amines (mēnz´),
n.pl organic compounds that contain nitrogen. , it would be expected that the treatment of BIIR with an aminoalcohol would result in the corresponding quaternization reaction (ref. 9). The now modified BIIR possesses a hydroxyl group bound to the main chain which should, in principle, be able to hydrogen bond hydrogen bond
A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom, especially a nitrogen, oxygen, or fluorine atom, usually of another molecule. with the polar silica surface (figure 4) (ref. 10). It is also important to note that intermittent coupling of the BIIR and silica could occur as a result of the base catalyzed condensation of the aminoalcohol hydroxyl groups and the silica surface silanol units.
[FIGURE 4 OMITTED]
If the level of interaction is sufficient, it should be possible to use these species to effectively compatabilize BIIR and silica and ultimately develop silica tread formulations containing BIIR. Importantly, this compatibilization method does not result in alcohol evolution (c.f. figure 3). The following sections detail our studies into the use of aminoalcohols as compatibilizers for silica in BIIR compounds.
All of the polymers, fillers and standard compounding ingredients which were used are commercially available materials. N,N-dimethylaminoethanol (2) and hexamethyldisilazane (5) were obtained from Aldrich Chemical and used as received. Brominated 2,2,4,8,8-pentamethyl-4-nonene (3) was prepared as described previously (ref. 11).
Mixing was done on an internal mixer, 1.5 L or 1.6 L, in conjunction with either a 6" x 12" or 10" x 20" mill. Dynamic properties were determined with the use of a GABO Eplexor equipped with an automated sampling system. Test strips wine cut from a 2 mm macro sheet that was cured for tc90+5 minutes at 160[degrees]C. Measurements were taken from -100[degrees]C to 100[degrees]C at a frequency of 10 Hz, a static deformation of 3% and a dynamic deformation of 0.1%. Stress-strain measurements were determined at 23[degrees]C according to according to
1. As stated or indicated by; on the authority of: according to historians.
2. In keeping with: according to instructions.
3. ASTM ASTM
American Society for Testing and Materials 412 Method A. Samples for stress-strain measurements were cut from a 2 mm macro sheet, cured for tc90+5 minutes, using Die C. Hardness values were determined using an A scale durometer according to ASTM 2240. Compound abrasion resistance was measured with the use of a DIN abrader equipped with 60-grit emery paper according to DIN 53516. Sample buttons were cured for tc90+10 min. at 160[degrees]C. Compound Mooney scorch was measured at 135[degrees]C according to ASTM 1646. Cure characteristics were determined with the use of a moving die rheometer rhe·om·e·ter
An instrument for measuring the flow of viscous liquids, such as blood. according to ASTM 5289. Cure profiles were determined at 160[degrees]C at a frequency of 1.7 Hz and a deformation of 1[degrees]. Payne effect The Payne effect is a particular feature of the stress-strain behaviour of rubber, especially rubber compounds containing fillers such as carbon black. It is named after the British rubber scientist A. R. Payne, who made extensive studies of the effect (e.g. Payne 1962). measurements were made with a rubber process analyzer. Measurements were conducted at 100[degrees]C, a frequency of 30 cpm and at 0.5, 1, 2, 5, 10, 20, 50 and 90[degrees] strains. NMR NMR: see magnetic resonance. spectra were recorded with a spectrometer spectrometer
Device for detecting and analyzing wavelengths of electromagnetic radiation, commonly used for molecular spectroscopy; more broadly, any of various instruments in which an emission (as of electromagnetic radiation or particles) is spread out according to some (400.13 MHz (MegaHertZ) One million cycles per second. It is used to measure the transmission speed of electronic devices, including channels, buses and the computer's internal clock. A one-megahertz clock (1 MHz) means some number of bits (16, 32, 64, etc. [sup.1]H) in CD[Cl.sub.3] with chemical shifts referenced to tetramethylsilane.
Synthesis and isolation of (E/Z)-N,N-dimelhyl-N-(2-hvdroxyethyl)-6,6-dimethyl-2-(2,2-dimethylpropyl) hept-2-enylammonium 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. , 4
A solution of M3 (0.0914g, 0.332 mmol), M2 (0.031g, 0.348 mmol) and dodecane (0.2 mL) was heated at 100[degrees]C for 4 h yielding a brown solid. The reaction mixture was filtered, washed with hexanes, and the solid residue dissolved in [Et.sub.2]O and washed with distilled water Noun 1. distilled water - water that has been purified by distillation
H2O, water - binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; (2 x 10 mL), saturated KHC KHC Kingdom Holding Company
Khc Christianshavn (Danish railway station)
KHC Klingon High Council (Star Trek)
KHC Karnataka High Court (Karnataka, India) [O.sub.3] (2 x 10 mL) and saturated NaCl (2 x 10 mL). The organic phase was isolated and the mixture was concentrated in vacuo in vacuo /in vac·uo/ (vak´u-o) [L.] in a vacuum. . Volatile components were removed by Kugelrohr distillation distillation, process used to separate the substances composing a mixture. It involves a change of state, as of liquid to gas, and subsequent condensation. The process was probably first used in the production of intoxicating beverages. (P = 0.6 torr torr (tōr),
n a unit of pressure equivalent to 0.001316 atmosphere; named after the physicist Torricelli. Also called
mm Hg. , T = 80[degrees]C) to give the residue. High-resolution MS analysis; required for [C.sub.18][H.sub.38]O[N.sup.+] m/e 284.2953, found m/e 284.2953. [sup.1H] NMR (CD[Cl.sub.3]): [delta] 0.8-2.2 (m, 25.88H, 2 x -C[(C[H.sub.3]).sub.3], 3 x -C[H.sub.2]-), 3.26 (s, 2.45H, -C[H.sub.3]), 3.28 (s, 3.62H, -C[H.sub.3]), 3.67 (t, 0.48H, -N-C[H.sub.2]), 3.76 (t, 1.61 H, -N-C[H.sub.2]), 4.03 (s, 0.73H, = C-C C-C Carbon-Carbon
C-C Carotid-Cavernous (relating to the carotid artery and the sinuses) [H.sub.2]), 4.05 (s, 1.27H, = C-C[H.sub.2]), 4.19 (m, 2.11H, C[H.sub.2]-OH), 5.77 (m, 0.97H, -OH), 5.89 (t, 0.78H, = C-H), 6.00 (t, 0.21 H, = C-H).
Preparation of surface functionalized silica
To 442 g of HiSil 233 suspended in 3,000 mL of hexane hexane /hex·ane/ (hek´san) a saturated hydrogen obtained by distillation from petroleum.
n. was added 24.9 mL of 2 and 14.0 mL of 5. The resulting mixture was agitated ag·i·tate
v. ag·i·tat·ed, ag·i·tat·ing, ag·i·tates
1. To cause to move with violence or sudden force.
2. at RT for a period of 8 h. The surface modified silica was separated by filtration and dried at 60[degrees]C to a constant weight.
Results and discussion
Our initial studies were centered around the basal aminoalcohol, ethanolamine ethanolamine /eth·a·nol·amine/ (eth?ah-nol´ah-men) monoethanolamine.
ethanolamine oleate , M1, and its effect on the physical properties of simple BIIR-silica compounds. The first series of compounds studied (A through C) were prepared according to the recipe and mixing sequence given in table 1.
As can be seen from the data presented in table 2, the introduction of M1 into a simple BIIR-silica formulation results in a dramatic improvement in the degree of filler reinforcement. Specifically, the M300/M100 value for B is significantly higher than that observed for A, while the DIN abrasion volume loss measured for B is considerably lower than that measured for the control compound. Measurement of the strain dependence of the complex modulus, [G.sup.*], (Payne effect) suggests that M1 is effectively compatibilizing the BIIR and silica surfaces (figure 5) (refs. 12 and 13). However, as M1 contains a 1[degrees] (primary) amine amine (əmēn`, ăm`ēn): see under amino group.
Any of a class of nitrogen-containing organic compounds derived, either in principle or in practice, from ammonia (NH3). center, the scorch safety of this compound (and therefore processability) was quite poor.
[FIGURE 5 OMITTED]
It is well known that BIIR compounds can be cured in the presence of amines. Recent work aimed at elucidating this mechanism has shown that the crosslinking process involves an initial N-alkylation reaction, followed by a deprotonation step. The resulting, neutral, amine substituted BIIR can then undergo an additional N-alkylation reaction to form a covalent crosslink (figure 6) (ref. 9).
[FIGURE 6 OMITTED]
As a result of the required deprotonation step, amine crosslinking can only occur with either a 1[degrees] (primary) or 2[degrees] (secondary) amine. For this reason, the methylated meth·yl·ate
An organic compound in which the hydrogen of the hydroxyl group of methyl alcohol is replaced by a metal.
tr.v. meth·yl·at·ed, meth·yl·at·ing, meth·yl·ates
1. 3[degrees] (tertiary) analogue of M1, N,N-dimethylaminoethanol M2, was investigated as an alternative silica modifier (programming) modifier - An operation that alters the state of an object. Modifiers often have names that begin with "set" and corresponding selector functions whose names begin with "get". . While compounds based on M2 possessed improved physical properties and increased levels of filler dispersion, the use of M2 resulted in no improvement in scorch safety.
Our results with M2 suggest that there is an additional crosslinking mechanism at work in these compounds. As a first step in establishing this mechanism, it is necessary to establish the role of both the amine groups and hydroxyl groups of M1 and M2 in their reaction with BIIR. To this end, the reaction between brominated 2,2,4,8,8-pentamethyl-4-nonene (BPMN BPMN Business Process Modeling Notation , M3) and M2 was studied in solution (figure 7). The results of this study indicate that 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.
n. occurs exclusively at the nitrogen center to give the corresponding substitution product substitution product
A product obtained by replacing one atom or group in a molecule with another atom or group. M4 (figure 9). Since there is no evidence for allylic ether ether, in chemistry
ether, any of a number of organic compounds whose molecules contain two hydrocarbon groups joined by single bonds to an oxygen atom. formation, we can rule out the participation of the hydroxyl hydroxyl /hy·drox·yl/ (hi-drok´sil) the univalent radical OH.
The univalent radical or group OH, a characteristic component of bases, certain acids, phenols, alcohols, carboxylic functionality (at the allylic bromide) in the crosslinking reaction.
[FIGURES 7 & 9 OMITTED]
The incorporation of silica into a rubber formulation results in the introduction of acidic acidic /acid·ic/ (ah-sid´ik) of or pertaining to an acid; acid-forming.
adj having the properties of an acid; acid-forming properties. Si-OH groups which can potentially affect the cure chemistry. While standard sulfur-accelerator cure systems are accelerated by basic species, the ZnO component of the BIIR cure is acid catalyzed (refs. 1, 14 and 15). Therefore, the presence of silica (i.e., SiOH groups) would be expected to increase the overall cure reactivity. For this reason, the effect of hexamethyldisilazane M5, a well known silylating reagent reagent /re·a·gent/ (re-a´jent) a substance used to produce a chemical reaction so as to detect, measure, produce, etc., other substances.
n. , on the scorch safety of BIIR-silica formulations was studied.
The silyl transfer reaction occurring between silica and M5 results in the substitution of polar silanol functionalities with non-polar trimethylsiloxane groups (figure 8) (refs. 10 and 16). This results in a surface modified silica which should be easier to disperse within BIIR and not accelerate the cure chemistry.
[FIGURE 8 OMITTED]
Compounds utilizing both M2 and M5 (see table 1) possessed comparable physical properties to those prepared with M2 alone. As anticipated, the introduction of M5 into the formulation resulted in a marked improvement in the scorch safety (table 2). It is important to note that the silylation reaction results in the formation of ammonia gas. As the reaction between M5 and the silica surface results in formation of free N[H.sup.3], one would expect to observe rapid BIIR crosslinking. However, since N[H.sub.3] is produced at the silica surface, it is reasonable to assume that it would immediately react with surface silanol groups to yield the corresponding ammonium ammonium /am·mo·ni·um/ (ah-mo´ne-um) the hypothetical radical, NH4, forming salts analogous to those of the alkaline metals.
ammonium carbonate silicate silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may be considered chemically as salts of the various silicic acids. . The lack of free ammonia was subsequently verified through head space analysis.
Based on our initial work, there appears to be a secondary crosslinking reaction which is occurring in the presence of M2. We have been able to show that this reaction(s) proceeds even in the absence of silica. While work aimed at elucidating the nature of this crosslinking reaction is ongoing, the delayed release of M2 into the elastomer matrix and the resulting effect on compound scorch satiety satiety
being in a state of satiation; in experimental animals used with reference to eating and drinking.
located in the ventromedial hypothalamic nucleus. were studied. To this end, a surface functionalized silica was prepared which contained levels of adsorbed M2 and M5 (compound E) which were comparable to those present in compound D. As can be seen from the data presented in table 2, the use of surface functionalized silica resulted in a further improvement in the t03 scorch time without compromising the other physical properties.
As a first step towards the development of a practical tread compound utilizing the above described technology, blends of BIIR silica (compound D without curatives) and BR-CB (compound F, table 3) masterbatches (MB) were investigated. Various compounds were prepared by taking the appropriate amount of each masterbatch and blending them on a 6" x 12" mill for 10 minutes at 100[degrees]C. The curatives were then added on a room temperature mill (table 4).
Analysis of the resulting formulations revealed a negative influence of BIIR-MB content on compound abrasion resistance. Conversely, an increase in BIIR-MB content resulted in an increase in the tan [delta] (0[degrees]C) value. If the value of tan [delta] (0[degrees]C) is taken to be an indication of wet traction performance, the results of this study can be taken as a confirmation of the positive influence of BIIR content on wet traction. In order to identify a BIIR/BR blend ratio for further optimization, a comparison of these compounds with two standard tread formulations (reinforced with either CB or silica) was made (compounds N and O, tables 5 and 6). On the basis of DIN abrasion volume loss, the 1:1 BIIR:BR blend compound was identified as the most promising candidate. Following a series of optimization studies, the final BIIR/BR formulation can be found as compound P. Analysis of compound P has shown this material to possess an acceptable hardness level (ca. 65 pts.), comparable (c.f. N and O) physical reinforcement and improved abrasion resistance. Importantly, the excellent physical properties did not come at the expense of the amiable dynamic properties inherent to BIIR. The temperature dependence of the loss factor was significantly broader than that observed for either witness compound, as shown in figure 10. The broader mechanical glass transition, along with the higher tan [delta] (0[degrees]C) value suggests that compound P will possess superior traction behavior than either of the control formulations (figure 10).
[FIGURE 10 OMITTED]
During formulation development, attention must be given to the cost implications associated with the employment of a new technology. With the results presented above, we have shown that it is possible to improve wet traction (predicted) performance by incorporating a significant amount of BIIR into a tread formulation. Importantly, this can be done without adversely affecting the physical properties (as determined in the laboratory) of the resulting compound. The incorporation of BIIR into a tread formulation would be expected to increase the compound cost. However, it is important to note that the modifiers used for the BIIR-based technology are far less expensive than those used in conventional silica tread technology (e.g., TESPT). With these factors taken into account, the cost per kg. (for elastomers, fillers and modifiers only) for each of the witness compounds and test compound P was determined using recent, publicly available, component list prices (table 7).
As can be seen from the data presented in table 7, the use of the inexpensive silica modifiers M2 and M5 allows the preparation of cost competitive BIIR tread formulations. Importantly, the cost of the BIIR test compound is significantly less expensive than that determined for the conventional silica tread formulation.
By using an affordable silica modifier system based on N,Ndimethylaminoethanol and hexamethyldisilazane, we have been able to significantly improve the interaction between BIIR and silica. This newly developed technology has been successfully applied in the preparation of a BIIR/BR-based tread compound. When compared to standard tread formulations, this compound was found to possess comparable physical properties and improved dynamic behavior. Specifically, the broad mechanical glass transition centered around -20[degrees]C was found to be more pronounced for test compound P than for either witness formulation. Based on this, the BII/BR compound would be expected to possess superior wet traction behavior. Importantly, this performance enhancement does not incur a cost penalty. In fact, the price per kg of the BIIR/BR compound was determined to be (based on current list pricing) less than that calculated for the silica-based witness compound.
Table 1--recipes and mixing sequence for compounds A-E Compound Tag A B C D E * BB2030 1a 100 100 100 100 100 HiSil 233 1b 60 60 60 60 60 1 1c 2.2 2 1c 3.2 3.2 3.2 * 5 1c 2.9 2.9 * MgO 1d 1 1 1 1 1 Sulfur 2a 0.5 0.5 0.5 0.5 0.5 Stearic acid 2a 1.0 1.0 1.0 1.0 1.0 ZnO 2a 1.5 1.5 1.5 1.5 1.5 Mixing sequence (1.5 L. internal mixer) t = 0 min. Add 1a, 1/2 of 1b and 1/2 of 1c t = 1 min. Add 1/4 of 1b t = 2 min. Add 1/4 of 1b and 1/2 of 1c and 1d t = 4 min. Sweep t = 6 min. Dump * Compounds 2 and 5 were pre-adsorbed into silica surface. Table 2--phycical properties for compounds A-E Compound A B C D E Hardness A2 Inst. (pts.) 77 72 65 54 58 Ultimate tensile (MPa) 13.9 17.5 21.5 18.3 18.4 Ultimate elongation (%) 736 343 353 585 498 25% modulus (MPa) 1.95 1.83 1.29 0.73 1.08 50% modulus (MPa) 1.93 2.31 1.85 1.05 1.33 100% modulus (MPa) 1.98 3.67 3.65 1.73 2.16 200% modulus (MPa) 3.13 8.24 10.50 4.42 5.69 300% modulus (MPa) 4.98 14.50 17.92 8.21 10.55 M300/M100 2.52 3.95 4.91 4.75 4.88 DIN abrasion loss 450 255 180 161 182 (m[m.sup.3]) Mooney scorch, 103 11.1 1.4 1.4 4.9 10.8 @ 135[degrees]C (min.) Table 3--BR-CB masterbatch recipe Compound Tag F Taktene 1203 1a 100 CB N234 1b 60 CalSol 8240 1b 15 Sunolite 160 prills 1b 1.5 Stearic acid 1b 2 Zinc oxide 1b 3 TMQ 1c 1 6PPD 1c 1 Mixing sequence (1.5 L internal mixer) t = 0 minute Add 1a t = 1 minute Add 1b t = 2 minute Add 1c t = 4 minute Sweep t = 6 minute Dump Table 4--preparation and physical properties of BIIR-RR blends Compound G H I J F (g) 400 320 240 200 D (g) 0 80 160 200 Curatives Sulfur (g) 3.27 2.86 2.45 2.25 Vulkacit NZ (TBBS) (g) 1.96 1.57 1.18 0.98 Stearic acid (g) 0.00 0.49 0.98 1.23 ZnO (g) 0.00 0.74 1.47 1.84 Physical properties Hardness A2 inst. (pts.) 55 48 50 51 Ultimate tensile (MPa) 18.1 13.9 14.0 16.9 Ultimate elongation (%) 614 667 617 587 25% modulus (MPa) 0.72 0.54 0.57 0.59 50% modulus (MPa) 0.98 0.73 0.80 0.86 100% modulus (MPa) 1.41 1.00 1.18 1.37 200% modulus (MPa) 3.24 2.13 2.67 3.55 300% modulus (MPa) 6.83 4.39 5.45 7.2 DIN abrasion loss ([mm.sup.3]) 53 87 88 114 Mooney scorch, t03 @ 135[degrees]C (min.) 21.7 17.1 8.9 6.4 Tan [delta] (0[degrees]C) 0.26 0.37 0.47 0.54 Compound K L M F (g) 16 80 0 D (g) 240 320 400 Curatives Sulfur (g) 2.04 1.63 1.23 Vulkacit NZ (TBBS) (g) 0.78 0.39 0.00 Stearic acid (g) 1.47 1.96 2.45 ZnO (g) 2.21 2.94 3.68 Physical properties Hardness A2 inst. (pts.) 50 52 53 Ultimate tensile (MPa) 14.8 17.5 22.8 Ultimate elongation (%) 527 414 478 25% modulus (MPa) 0.60 0.63 0.65 50% modulus (MPa) 0.91 0.99 0.99 100% modulus (MPa) 1.59 1.86 1.75 200% modulus (MPa) 4.55 5.61 5.7 300% modulus (MPa) 9.14 11.52 12.88 DIN abrasion loss ([mm.sup.3]) 116 237 210 Mooney scorch, t03 @ 135[degrees]C (min.) 6.4 5.4 4.5 Tan [delta] (0[degrees]C) 0.59 0.61 0.81 Table 5--preparation of witness compounds N and O and BIIR/BR tread compound P Compound Tag N O P BB2030 1a 70 70 50 Buna VSL 5025-O 1a 30 30 Taktene 1203 1a 80 50 HiSil 233 1b 6.4 30 Silane TESPT (Si69) 1b 2 1b 1.4 5 1b 0.73 CB N234 1c 80 50 Stearic Acid 1d 1 Calsol 8240 1d 7.5 Sundex 790 1d 9 9 Sunolite 160 prills id 1.5 1.5 0.75 Stearic acid 1e 1 1 (6PPD) 1e 1 1 0.5 (TMQ) 1e 1 1 0.5 Zinc oxide 1e 2.5 2.5 Sulfur 2a 1.4 1.4 1 (CBS) 2a 1.7 1.7 1 (DPG) 2a 2.0 Zinc oxide 2a 2 Mixing sequence (1.6 L internal mixer) For N and O For P t = 0.0 min. Add1a t = 0.0 min. Add 1a t = 1.0 min. Add 1/2 of 1b + 1/2 of 1c t = 0.5 min. Add 1b t = 2.0 min. Add 1/2 of 1b + 1/2 of 1c t = 2.0 min. Add 1c t = 3.0 min. Add 1d t = 3.0 min. Sweep t = 5.0 min. Add 1e t = 3.5 min. Add 1d + le t = 6.0 min. Dump t = 5.0 min. Sweep t = 6.0 min. Dump Add 2a on RT 10" x 20" mill Table 6--properties of witness compounds N and O and BIIR/BR tread compound P Compound N O P Hardness A2 Inst. (pts.) 76 80 65 Ultimate tensile (MPa) 16.3 12.4 14.1 Ultimate elongation (%) 301 212 423 25% modulus (MPa) 1.82 2.08 121 50% modulus (MPa) 2.53 2.96 1.72 100% modulus (MPa) 4.31 5.20 2.94 200% modulus (MPa) 10.6 11.6 6.16 300% modulus (MPa) 16.2 10.19 DIN abrasion loss ([mm.sup.3]) 140 140 118 Mooney scorch, t03 12.3 23.1 7.0 @ 135[degrees]C (min.) Table 7--price comparison for compounds N-P Cost Cost N O P U.S./lb. U.S./kg BB2030 1.35 2.98 50 Buna VSL 5025-0 0.82 1.81 70 70 Taktene 1203 0.80 1.76 30 30 50 HiSil 233 1.20 2.65 80 30 CB N234 0.56 1.23 80 50 Silane Si69 9.20 20.28 6.4 2 1.33 2.93 1.4 5 5.75 12.68 0.73 Total price 278.22 520.91 391.45 (U.S.)Price U.S./kg 1.55 2.79 2.15
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