Stephen Seneker, Robert Czeiszperger, Jordan Duckett and Elizabeth June Anderson Development Company 1415 E. Michigan Street Adrian, MI ABSTRACT

Transcription

1 Conventional and Reduced-Free Prepolymers Based on trans-1,4-h6xdi: Elastomer Physical/Mechanical Properties, Dynamic Performance and Chemical/Solvent Resistance Stephen Seneker, Robert Czeiszperger, Jordan Duckett and Elizabeth June Anderson Development Company 1415 E. Michigan Street Adrian, MI ABSTRACT Previously, polyurethane elastomer systems based on the new aliphatic diisocyanate, Fortimo trans-1,4-h6xdi (trans-1,4- hydrogenated xylylene diisocyanate) were introduced. This new aliphatic diisocyanate has a very compact, linear and symmetrical structure which results in ultra high-performance properties comparable to elastomers based naphthalene diisocyanate (DI), para-phenylene diisocyanate (PPDI) and o-tolidine diisocyanate (TODI). In this paper, the dynamic properties of trans-1,4-h6xdi elastomers will be presented in the form of dynamometer testing results of high-load wheels. The chemical and solvent resistance properties will be shown as a function of the diisocyanate structure and composition of the soft-segment backbone. Physical/mechanical properties of trans-1,4-h6xdi prepolymers cured with aromatic diamines will be introduced. Additionally, elastomer property data for low-free and reduced-free diisocyanate monomer prepolymers will be presented. ITRODUCTIO The two major classes of cast polyurethane elastomers are those based on the aromatic diisocyanates MDI (methylene diphenyl diisocyanate) and TDI (toluene diisocyanate). These two classes of elastomers give properties which meet or exceed the requirements of a majority of applications. However, there are applications which require extra dynamic performance, tear strength, abrasion resistance or other properties which cannot be met by MDI and TDI-based elastomers. For these types of applications, ultra high-performance diisocyanates such as DI (naphthalene diisocyanate), PPDI (para phenylene diisocyanate) or TODI (o-tolidine diisocyanate) are used. 1-5 These types of elastomers have superior dynamic performance, and excellent tear and abrasion resistance. There are certain ultra high-performance applications which require excellent light stability. The previously mentioned aromatic diisocyanate systems fail to meet this requirement as they yellow or become dark over time when exposed to light. In the past, one would need to use an aliphatic diisocyanate such as H 12 MDI [hydrogenated methylene bis(phenyl isocyanate)] or IPDI (isophorone diisocyanate) for these applications. Elastomers based on H 12 MDI and IPDI are not considered ultra high-performance as they have inferior physical/mechanical and dynamic properties. A new ultra highperformance aliphatic diisocyanate, which is called Fortimo TM 1,4-H6XDI, has been developed and commercialized by Mitsui Chemical to meet this specialized market need. Throughout this paper it will be referred to as trans-1,4-h6xdi. Last year, the physical/mechanical properties, thermal mechanical behavior and abrasion resistance properties of elastomers based on trans-1,4-h6xdi were presented. 7 In this paper, information is expanded with solvent/chemical resistance data, high-load wheel dynamometer testing results, and physical/mechanical properties of trans-h6xdi elastomers using the aromatic diamine curative MCDEA [4,4 -methylene bis(3-chloro-2,6-diethylaniline)] and the use of a polycarbonate polyol as a backbone. Additionally, a new abrasion resistance additive is introduced called Andur Glide 4830.

2 RESULTS AD DISCUSSIO Ultra High-Performance Diisocyanates Figure 1 illustrates the current commercially available ultra high-performance aromatic diisocyanates: DI, PPDI and TODI. As one can see from the structures of these diisocyanates, they are all very compact, linear and symmetrical with respect to the isocyanate groups. Mitsui Chemical has introduced a new aliphatic ultra high-performance diisocyanate called Fortimo 1,4-H6XDI which is shown in Figure 2. The structure of the aliphatic trans-1,4-h6xdi is very compact like the other ultra high-performance diisocyanates. Since it is enriched in the trans isomer, it has a very linear and symmetrical structure with respect to the two isocyanate groups. O Figure 1: Chemical Structures of DI, PPDI and TODI C O C O H 3 C CH 3 O C C C C O O Figure 2: Chemical Structure of trans-1,4-h6xdi H C O CH 2 O C CH 2 H AndurElite Prepolymers Based on trans-1,4-h6xdi versus other Ultra High-Performance Diisocyanates Conventional AndurElite trans-1,4-h6xdi prepolymers and TODI prepolymers are easier to process than conventional PPDI prepolymers in that PPDI will sublime and coat itself on the interior of the container surfaces above the liquid level. The sublimed PPDI monomer can build up over time making it a challenge to keep equipment from fouling. Trans-1,4- H6XDI prepolymers have aliphatic isocyanate groups that are much less reactive with moisture in the air, so they do not skin over as readily as PPDI or TODI based prepolymers. Additionally, trans-1,4-h6xdi prepolymers have much less of a tendency to form allophanate crosslinks resulting in a much longer shelf life at ambient temperature and higher stability at elevated processing temperatures. Shelf life and stability are of particular importance when using high-value, ultra highperformance prepolymers since one does not want to have to dispose of a partial container of compromised material. Prepolymer Processability of trans-1,4-h6xdi Prepolymers versus other Ultra High-Performance Diisocyanates Prepolymers based on trans-1,4-h6xdi cured with 1,4-butanediol can be catalyzed to achieve the same processing characteristics as PPDI and TODI systems. As shown from the data in Table 1, the pot life along with the demold time can be reduced easily by using catalyst. For the aromatic diisocyanate prepolymers (PPDI and TODI), the amine catalyst, triethylene diamine (TEDA) is the preferred catalyst since one can use a relatively sizable amount (200 to 800 ppm). Whereas, if one used a metal catalyst like dibutyltin dilaurate (DBTDL) then one would have to use amounts in the 5 to 20 ppm range which is very difficult to add and control. For the trans-1,4-h6xdi prepolymer, one has to use a metal catalyst since amine catalysts are not very effective with aliphatic isocyanates. Using DBTDL catalyst in the range of 100 to 300 ppm gives a very workable range of pot life from 10 to 1.5 minutes. Please note it is generally known that a shorter pot life with these ultra high-performance elastomer systems results in better processability (improved green strength), reduced demold time, and improved physical/mechanical properties.

3 Table 1: Processing Characteristics of Prepolymers Based on 2000 MW Polycaprolactone (PCL) using 1,4-Butanediol Diisocyanate Catalyst Pot Life (minutes, Demold Time Catalyst Type Prepolymer % CO Amount (ppm) seconds) (minutes) trans-1,4-h6xdi 7.8 DBTDL to to to PPDI 4.1 TEDA to to 2 30 TODI 6.3 TEDA to to to Elastomer Physical/Mechanical Properties Based on trans-1,4-h6xdi versus PPDI and TODI As a matter of review, the physical/mechanical properties of 93 Shore A elastomers based on trans-1,4-h6xdi, PPDI and TODI are shown in Table 2. These elastomers were cast using a prepolymer temperature of 180ºF (85ºC) using 1,4- butanediol as curative at room temperature. They were catalyzed to a pot life of 2 minutes using DBTDL for the trans-1,4- H6XDI and TEDA for the PPDI and TODI systems. The mold temperature was 240ºF (116ºC). The elastomers were demolded and then post cured overnight at 212ºF (100ºC) for about 16 hours. The elastomer plaques were conditioned at 73ºF (23ºC) and 50% humidity for at least two weeks prior to testing the physical/mechanical properties. The compression sets were determined after at least four weeks conditioning. Table 2: Physical/Mechanical Properties of Elastomers based on trans-1,4-h6xdi, PPDI and TODI, 2000 MW Polycaprolactone (PCL) Prepolymers cured with 1,4-Butanediol trans-1,4-h6xdi PPDI TODI Hardness, Shore 93A 93A 93A Elongation, % Tensile Strength, psi (MPa) 7400 (51.0) 6100 (42.1) 5000 (34.4) 100% Modulus, psi (MPa) 1370 (9.4) 1300 (9.0) 1200 (8.3) 300% Modulus, psi (MPa) 2000 (13.8) 1800 (12.4) 1600 (11.0) Die C Tear, pli (k/m) 650 (114) 590 (104) 570 (100) Split Tear, pli (k/m) 490 (86) 400 (70) 440 (77) Bashore Rebound, % Compression Set, % (22 70ºC) Abrasion Resistance, (Volume Loss,mm 3 ) ASTM D As one can see from the data above, the trans-1,4-h6xdi elastomer had the highest elongation and tensile strength. So the area under the stress/strain curve is significantly higher for the trans-1,4-h6xdi elastomer indicating the highest overall toughness. The Die C tear strength is higher for the trans-1,4-h6xdi elastomer, whereas, the PPDI and TODI are comparable. The split tear strength was highest for the trans-1,4-h6xdi followed by the TODI then the PPDI elastomer. The trans-1,4-h6xdi and PPDI had equivalent Bashore rebound at 68% and the TODI based elastomer was significantly lower at 57%. The compression sets of all three elastomers were comparable after 22 hours at 70ºC. The abrasion resistance was measured using a rotary drum abrader via ASTM D5963. These results showed that the PPDI elastomer has a higher abrasion resistance than either the trans-1,4-h6xdi or TODI elastomer. Thermal Mechanical Properties of trans-1,4-h6xdi, PPDI and TODI Based Elastomers The thermal mechanical properties of the trans-1,4-h6xdi, PPDI and TODI based elastomers were determined using dynamic mechanical thermal analysis (DMTA). An overlay of the storage modulus curves is shown in Figure 3. This

4 figure shows that all three elastomers have a very flat rubbery plateau region. The beginning of the melting transition is comparable for all three elastomers, however, the trans-1,4-h6xdi elastomer drops off more sharply. In the soft segment glass transition area, the trans-1,4-h6xdi elastomer has a significant shoulder which is likely melting of crystallized PCL soft segment. Figure 3: Storage Modulus Curves for the trans-1,4-h6xdi, PPDI and TODI Elastomers An overlay of the tan delta curves is shown in Figure 4. The beginning of the tan delta peak is an indication of the brittle point temperature of an elastomer. One can see that the trans-1,4-h6xdi elastomer has the lowest brittle point, closely followed by the PPDI elastomer and then the TODI elastomer. The tan delta peak reaches the rubbery plateau at a lower temperature for the PPDI than the trans-1,4-h6xdi. This may be due to some crystallization in the soft segment in the trans-1,4-h6xdi elastomer as suggested previously. The tan delta in the rubber plateau region is an indication of the heat buildup tendency of the elastomer in a dynamic application. The lower the tan delta, the lower the heat buildup. One can see from the curves that the trans-1,4-h6xdi and PPDI have comparably low tan delta s in the typical temperature use range of polyurethane elastomers, whereas, the TODI elastomer has a significantly higher tan delta. This observation agrees with the lower Bashore rebound or resilience of the TODI elastomer versus the trans-1,4-h6xdi and PPDI elastomers. Figure 4: Tan Delta Curves for the trans-1,4-h6xdi, PPDI and TODI Elastomers

5 Flex Fatigue Resistance of Elastomers Based on trans-1,4-h6xdi versus DI, PPDI and TODI The flex fatigue resistance was measured using the De mattia flexural fatigue tester as shown in Figure 5. The samples were cycled at 5 Hz for a distance from 0 to 60 mm. The specimens were notched 1 mm and then the crack head propagation was measured after every 1000 cycles up to 5000 cycles. The results are shown in Figure 6. Polycaprolactone (PCL) was used as the backbone for all the elastomers. The elastomer based on 1,4-H6XDI performed the best at just 2 mm crack propagation, followed by DI and PPDI at 5 mm and then the TODI at about 15 mm. The TDI/PCL/MBOCA elastomer failed after less than 500 cycles. Figure 5: De mattia Flexural Fatigue Tester Figure 6: De mattia Flexural Fatigue Test Results Accelerated UV Exposure of Elastomers Based on trans-1,4-h6xdi versus TDI, PPDI, DI and TODI The UV stability of the elastomer systems was evaluated using a Xenon arc tester. The specimens were exposed to the xenon arc UV light at 100W/m 2 for 1 week. Figure 7 shows the elastomer appearance before and after the exposure. As expected, the elastomer based on the aromatic diisocyanates TDI, PPDI, DI and TODI all increased significantly in color, whereas, the specimen based on trans-1,4-h6xdi remained relatively unaffected. Figure 7: Accelerated UV Exposure using Xenon Arc Tester

6 Elastomer Solvent/Chemical Resistance Properties of trans-1,4-h6xdi versus PPDI and TODI The solvent/chemical resistance was determined by immersing specimens at ambient temperature and measuring the weight percent gain after 10 days. The results are shown in Table 3. The trans-1,4-h6xdi elastomer performed the best versus PPDI and TODI in MP and THF which are known to be very aggressive towards polyurethanes. It swelled only 110% in MP versus TODI which swelled 900% and the PPDI elastomer dissolved. In THF, the trans-1,4-h6xdi elastomer swelled 93% versus 120 and 130% for the PPDI and TODI, respectively. For the rest of the solvents/chemicals, overall, the TODI-based elastomer swelled the least followed by PPDI and then the trans-1,4-h6xdi. Table 3: Solvent/Chemical Resistance of 93A trans-1,4-h6xdi/pcl/bdo Elastomers versus PPDI and TODI (Weight % swell after 10 days immersion at ambient temperature) trans-1,4-h6xdi PPDI TODI MP 110 dissolved 900 THF Toluene Methylethyl Ketone (MEK) Acetone Butyl Acetate Gasoline Isopropanol Diesel Transmission Fluid ASTM Oil # Dynamometer Testing of High-Load Wheels Based on 93A trans-1,4-h6xdi/pcl/1,4-bdo Elastomers High-load wheels were cast which were eight inches in diameter, two inches wide and had a tread thickness of 0.38 inches. The wheels were conditioned at least one month prior to dynamometer testing. The dynamometer testing was performed by Caster Concepts using their Dynamic Wheel Endurance Tester. The wheels were run at 6 mph using an initial load of 1000 lbs. The load was increased by 200 lbs every two hours until the wheel failed. The elastomer stoichiometry was varied from 0.95 down to 0.88 to determine its effect on the dynamometer results. The results in Table 4 show that the Load Failure increased as the stoichiometry decreased from 0.95 to 0.90 indicating that the optimum is a 0.90 stoichiometry for this trans-1,4-h6xdi/pcl/1,4-bdo elastomer system. The Failure Temperature decreased as the stoichiometry decreased because the wheels ran cooler due to less hysteresis. The effect of the stoichiometry on the physical/mechanical properties is shown in the next section. Table 4: Dynamometer Results of 93A trans-1,4-h6xdi/pcl/1,4-bdo Elastomer Stoichiometry Load Failure (lbs) Failure Temperature ( F) Effect of Stoichiometry on the Physical/Mechanical Properties of 93A trans-1,4-h6xdi/pcl/1,4-bdo Elastomers Shown below in Table 5 are the physical/mechanical properties of a 93A trans-1,4-h6xdi/pcl/1,4-bdo system cast at stoichiometries of 0.91, 0.95 and Going from 0.91 to 0.98 stoichiometry did not have much of an effect on the elongation, tensile strength, 100% and 300% modulus, Die C tear strength or Bashore rebound. As expected, it did have a major effect on the split tear strength and compression set. The split tear strength increased by about 15 percent going from

7 0.91 to 0.98 stoichiometry. The compression set increased slightly going from 0.91 to 0.95 stoichiometry and then increased significantly from 0.95 to 0.98 going from 28% to 38%. The above results indicate that a stoichiometry of 0.95 gives the best overall properties for most applications. However, as mentioned in the previous section, for high-load wheel applications it is best to use a stoichiometry of about 0.90 which will give a lower split tear strength but the other properties are not affected in a negative way. Table 5: Effect of Stoichiometry on the Physical/Mechanical Properties of the trans-1,4-h6xdi Elastomer Stoichiometry Hardness, Shore 93A 93A 93A Elongation, % Tensile Strength, psi (MPa) 7600 (52.4) 7400 (51.0) 6500 (44.8) 100% Modulus, psi (MPa) 1360 (9.4) 1370 (9.4) 1390 (9.6) 300% Modulus, psi (MPa) 1980 (13.7) 2000 (13.8) 1990 (13.7) Die C Tear, pli (k/m) 640 (112) 650 (114) 650 (114) Split Tear, pli (k/m) 460 (80.7) 490 (86) 520 (91.2) Bashore Rebound, % Compression Set, % (22 70ºC) Abrasion Resistance of 93A trans-1,4-h6xdi/pcl/1,4-bdo Elastomer using Andur Glide 4830 The effect of Andur Glide 4830 on the abrasion resistance of 93A trans-1,4-h6xdi/pcl/1,4-bdo elastomer is shown in Table 6. Andur Glide 4830 is a low viscosity liquid composed of a 30 weight percent dispersion of polyethylene/teflon copolymer particles in mineral spirits. It was incorporated at levels of 0, 1, 2 and 4 weight percent. The results show that the abrasion resistance more than doubles with only 2 weight % of Andur Glide 4830 at both a 0.90 and 0.95 stoichiometry. It continues to improve as the level of additive increases to 4 weight percent. Table 6: Effect of Andur Glide 4830 on Abrasion of 93A trans-1,4-h6xdi/pcl/1,4-bdo Elastomer Stoic Andur Glide 4830 (wt %) Average Abrasion Loss (mm 3 ) Physical/Mechanical Properties of trans-1,4-h6xdi/pcl Prepolymer Cured with 1,4-BDO versus MCDEA Physical/mechanical properties of a trans-1,4-h6xdi/pcl prepolymer cured with 1,4-BDO and MCDEA are shown in Table 7. This prepolymer has been commercialized and is called AndurElite CL 93 AP. Using 1,4-BDO as a curative, the system has to be catalyzed using a metal catalyst such as dibutyltin dilaurate. With an aromatic diamine such as MCDEA, no catalyst is required. In fact, AndurElite CL 93 AP has a very reasonable 4 to 5 minute pot life when cured with MCDEA. The 52 Shore D hardness is significantly higher than the 93A obtained with 1,4-BDO. As expected, the elongation is lower at 430% versus 760%. This is likely due to the fact that aromatic diamine cured systems result in urea linkages which form a more microphase versus macrophase separated hard-segment structure. Die C tear strength is lower, as compared to the split tear strength which is almost three times lower. Compression set is good for both curatives. Bashore rebound is lower which is to be expected since the hardness is higher at 52D versus 93A for the 1,4-BDO.

8 Table 7: AndurElite CL 93 AP (trans-1,4-h6xdi/pcl) Cured with 1,4-BDO and MCDEA Curative 1,4-BDO MCDEA Pot Life, minutes < 3* 4-5 Hardness, Shore 91-94A 50-54D Elongation, % Tensile Strength, psi (MPa) 7400 (51.0) 7000 (48.3) 100% Modulus, psi (MPa) 1370 (9.4) 2130 (14.7) 300% Modulus, psi (MPa) 2000 (13.8) 4040 (27.9) Die C Tear, pli (k/m) 650 (114) 550 (96) Split Tear, pli (k/m) 490 (86) 180 (32) Compression Set, % 70 C Bashore Rebound, % *Adjusted using Dabco T-12 (dibutyltin dilaurate) Physical/Mechanical Properties of trans-1,4-h6xdi/ptmeg Prepolymer Cured with 1,4-BDO Physical/mechanical properties of a trans-1,4-h6xdi/ptmeg prepolymer cured with 1,4-BDO are shown in Table 8. This prepolymer has been commercialized as AndurElite PT 93 AP. Elastomers based on a PTMEG backbone are known to have as superior hydrolysis resistance except for aqueous solutions with a temperature above 160 F. Overall physical/mechanical properties are good. Die C tear of 660 pli is comparable to the AndurElite CL 93 AP (polycaprolactone) of 650 pli. However, the spilt tear strength is significantly lower at 160 versus 490 pli. AndurElite PT 93 AP (PTMEG) would be recommended for applications that require long term resistance to an aqueous environment as well as overall excellent durability and weatherability. Table 8: AndurElite PT 93 AP (trans-1,4-h6xdi/ptmeg) Cured with 1,4-BDO Curative BDO Pot Life, minutes < 3* Hardness, Shore 91-94A Elongation, % 690 Tensile Strength, psi (MPa) 4600 (31.7) 100% Modulus, psi (MPa) 1340 (9.2) 300% Modulus, psi (MPa) 1860 (12.8) Die C Tear, pli (k/m) 660 (116) Split Tear, pli (k/m) 160 (28) Compression Set, % 70 C 20 Bashore Rebound, % 70 *Adjusted using Dabco T-12 (dibutyltin dilaurate) Physical/Mechanical Properties of Low Free and Reduced Free H6XDI/PTMEG Prepolymers Cured with 1,4-BDO Low-free and reduced-free trans-1,4-h6xdi/ptmeg prepolymers were prepared by stripping out the 1,4-H6XDI monomer using a wiped-film evaporator. The low free prepolymer had a 4.9% CO content with a 1,4-H6XDI monomer content of less than 0.1 weight percent and the reduced free prepolymer had a 6.0% CO content with a monomer content about 3 weight percent. These prepolymers were cured with 1,4-BDO using dibutyltin dilaurate catalyst at a 0.95 stoichiometry to achieve a pot life of less than 3 minutes. Physical/mechanical properties of these elastomers are shown in Table 9. Unexpectedly, the hardness of both these elastomers was about the same at a Shore hardness of 97A/46D with 100% moduli of 1430 and 1470 psi, respectively, despite the differences in the % CO content. Die C and split tear strength behaved as expected with the tear strength increasing with the added 1,4-H6XDI monomer content. Compression sets were comparable at 32 and 38%, respectively. Bashore rebounds were excellent at 70 and 69% and the abrasion loss was good at 89 and 87 mm 3.

9 Table 9: Low Free and Reduced Free trans-1,4-h6xdi/ptmeg Prepolymers Cured with 1,4-BDO H6XDI Monomer Content, wt % <0.1 3 % CO Shore Hardness 97A/46D 97A/46D Elongation, % Tensile Strength, psi (MPa) 4500 (31.0) 5700 (39.3) 100% Modulus, psi (MPa) 1430 (9.9) 1470 (10.1) 300% Modulus, psi (MPa) 1890 (13.0) 1950 (13.4) Die C Tear, pli (k/m) 470 (82) 560 (98) Split Tear, pli (k/m) 73 (13) 130 (23) Compression Set, % C Bashore Rebound (%) Avg Abrasion Loss, mm Physical/Mechanical Properties of trans-1,4-h6xdi/ptmeg Prepolymer Cured with MCDEA Physical/mechanical properties of a trans-1,4-h6xdi/ptmeg prepolymer cured with MCDEA are shown in Table 10. Using 1,4-BDO as a curative, it is generally known that the highest hardness achievable is about 60D using linear and symmetrical diisocyanates like MDI. The same is true with trans-h6xdi which is also linear and symmetrical. In order to achieve high hardness elastomers, one needs to use an aromatic diamine curative such as MCDEA. Table 10 shows a 74D system using MCDEA as a curative which has a relatively long pot life of 3 minutes. Overall physical/mechanical properties are excellent. This elastomer has an elongation of 230%, tensile strength of 7060 psi, Die C tear of 1070 pli and spilt tear of 195 pli. So this example illustrates that a high hardness system can be easily achieved using a trans-1,4-h6xdi prepolymer cured with MCDEA that has excellent processabity with a relatively long pot life of 3 minutes. Table 10: trans-1,4-h6xdi/ptmeg Prepolymer Cured with MCDEA Curative MCDEA Pot Life, minutes 3 Hardness, Shore 74D Elongation, % 230 Tensile Strength, psi (MPa) 7060 (48.7) 100% Modulus, psi (MPa) 5080 (35.0) 300% Modulus, psi (MPa) ---- Die C Tear, pli (k/m) 1070 (188) Split Tear, pli (k/m) 195 (34) Compression Set, % 70 C n.d. Bashore Rebound, % 57 Physical/Mechanical Properties of trans-1,4-h6xdi/polycarbonate Prepolymer Cured with 1,4-BDO Physical/mechanical properties of a trans-1,4-h6xdi/polycarbonate prepolymer cured with 1,4-BDO are shown in Table 11. This prepolymer has been commercialized as AndurElite PC 95 AP. Elastomers based on a polycarbonate backbone are known to have the best overall oil, solvent and chemical resistance as well as superior hydrolysis resistance except for aqueous acidic environments with a ph of less than 4. Overall physical/mechanical properties are good. The spilt tear strength is between that of the AndurElite CL 93 AP (polycaprolactone) and the AndurElite PT 93 AP (polytetramethylene glycol). AndurElite PC 95 AP (polycarbonate) would be recommended for applications that required the excellent toughness of a polyester or polycaprolactone with the added benefit of resistance to aqueous environments. Table 12 shows the effect of Andur Glide 4830 on the abrasion resistance of AndurElite PC 95 AP cured with 1,4-BDO. As expected, the abrasion resistance improved nearly by a factor of two with 2 weight % Andur Glide 4830 added.

10 Table 11: AndurElite PC 95 AP (trans-1,4-h6xdi/polycarbonate) Cured with 1,4-BDO Hardness, Shore 94-96A Elongation, % 470 Tensile Strength, psi (MPa) 6650 (45.9) 100% Modulus, psi (MPa) 1600 (11.0) 300% Modulus, psi (MPa) 3040 (21.0) Die C Tear, pli (k/m) 590 (104) Split Tear, pli (k/m) 220 (39) Compression Set, % 70 C 28 Bashore Rebound, % 52 Table 12: Effect of Andur Glide 4830 on Abrasion Resistance of AndurElite PC 95 AP (trans-1,4-h6xdi/polycarbonate) Cured with 1,4-BDO Stoic Andur Glide 4830 (wt %) Average Abrasion Loss (mm 3 ) COCLUSIOS AndurElite prepolymers based on the aliphatic diisocyanate trans-1,4-h6xdi have lower reactivity with moisture in the air resulting in less of a tendency to skin over in the container. They also have negligible side reactions to form allophonate crosslinks resulting in superior stability in regards to shelf life and heat resistance during processing. The above attributes are of particular importance when using high-value, ultra high-performance prepolymers since one does not want to have to dispose of a partial container of compromised material. Elastomer systems based on Mitsui s new aliphatic diisocyanate, Fortimo 1,4-H6XDI, exhibit ultra high-performance properties. This new aliphatic diisocyanate has a very compact, linear and symmetrical structure resulting in a superior hard segment with 1,4-butandiol that gives a high melting/softening temperature and great phase separation between the hard and soft segments. The physical/mechanical properties are superior or comparable to those based on other ultra highperformance diisocyanates like PPDI and TODI, in particular, the elongation, tensile strength, resilience (Bashore rebound) and tear strength. Elastomers based on trans-1,4-h6xdi have superior flex fatigue resistance as show by the De Mattia flexural fatigue tester results. As expected, since trans-1,4-h6xdi is an aliphatic diisocyanate, they have excellent light stability resulting in parts that retain their color over a much longer period of time than elastomers based on aromatic diisocyanates such as PPDI, DI, TODI, MDI or TDI. Dynamometer testing results of high-load wheels resulted in a load at failure up to 2200 lbs. The optimum stoichiometry for high-load wheels applications was determined to be 0.90 (CO/OH = 1.10). Anderson Development Company has commercialized three prepolymers based on trans-1,4-h6xdi: AndurElite CL 93 AP (polycaprolactone), AndurElite PT 93 AP (polytetramethylene glycol) and AndurElite PC 95 AP (polycarbonate). These prepolymers can be cured with 1,4-butanediol or aromatic diamines such as MCDEA. Curing with 1,4-butanediol requires a metal catalyst such as dibutyltin dilaurate, however, aromatic diamines do not required a catalyst and have very reasonable pot lives making them suitable for both hand casting and machine casting operations. A new abrasion resistance additive was introduced which is called Andur Glide Using this additive with an ultra high-performance system like the trans-1,4-h6xdi elastomers was shown to more than double the abrasion resistance using a loading of only 2 weight percent.

11 In summary, the results reported in this paper support that elastomer systems based on trans-1,4-h6xdi have the physical/mechanical toughness, thermal/mechanical profile, flex fatigue resistance, dynamic performance and abrasion resistance of ultra high-performance elastomer systems with the added benefit of being light stable. REFERECES 1) Denise Kenney, A Comparison of Polyurethane for High-Performance Applications, PMA Conference, May ) Jens Krause, Antonio Alvarez, Ashok Sarpeshkar, Storage Stable DI Prepolymers with Superior Mechanical and Dynamic Load Bearing Characteristics, PMA Conference, April ) Mark Ferrandino, Urethane Elastomers for High Temperature Applications, PMA Conference, May ) Wayne Whelchel, PPDI Paraphenylene Diisocyanate for High-Performance Polyurethanes, PMA Conference, October ) Vito Grasso, Cast Urethane for High Stress Dynamic Applications, PMA Conference, October ) Susan Gorman, A ew Generation of Cast Elastomers, PMA Conference, October ) Stephen Seneker, Robert Czeiszperger and Jordan Duckett, Ultra High-Performance Elastomers Based on Tran- Bis(Isocyanatomethyl) Cyclohexane, PMA Conference, April BIOGRAPHIES Steve Seneker Steve Seneker is a Senior Scientist in the Polyurethane Elastomers Group at Anderson Development Company. He received his B.A. Degree in Chemistry from Point Loma azarene College. He received his Ph.D. in Chemistry with an emphasis on Polymers and Coatings from orth Dakota State University. After graduation in 1986, he joined Mobay Corporation (currently Bayer Material Science). In 1993, he joined ARCO Chemical/Lyondell Chemical. He has been working at Anderson Development Company since Robert Czeiszperger Robert Czeiszperger is currently a Senior Principle Chemist in the Polyurethane Elastomers Group at Anderson Development Company. He has Bachelor s degrees in Chemistry and Mathematics from Siena Heights University and earned a Master s degree in Polymer and Coatings Technology from Eastern Michigan University in He has been working at Anderson Development Company since Jordan Duckett Jordan Duckett is currently a Urethane Technical Support Chemist in the Polyurethane Elastomers Group at Anderson Development Company. He has a Bachelor s degree in Chemistry from Siena Heights University. He has been working at Anderson Development Company since He began as an intern while attending Siena Heights University. Upon his graduation, he worked as a Quality Control Technician. In 2011, he accepted his current position at Anderson Development Company. Elizabeth June Elizabeth June is currently a Research and Development Chemist in the Polyurethane Elastomers Group at Anderson Development Company. She has a Bachelor s degree in Biochemistry from Adrian College. She has been working at Anderson Development Company since January She began as an intern while attending Adrian College. In ovember 2015, she accepted her current position at Anderson Development Company.