CA2235592A1 - Trimodal molecular weight polyether polyol prepolymers - Google Patents
Trimodal molecular weight polyether polyol prepolymers Download PDFInfo
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- CA2235592A1 CA2235592A1 CA002235592A CA2235592A CA2235592A1 CA 2235592 A1 CA2235592 A1 CA 2235592A1 CA 002235592 A CA002235592 A CA 002235592A CA 2235592 A CA2235592 A CA 2235592A CA 2235592 A1 CA2235592 A1 CA 2235592A1
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- Prior art keywords
- molecular weight
- toluene diisocyanate
- prepolymer
- polyether polyol
- polyol
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7614—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring
- C08G18/7621—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring being toluene diisocyanate including isomer mixtures
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
- C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation step
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/48—Polyethers
- C08G18/4804—Two or more polyethers of different physical or chemical nature
- C08G18/4808—Mixtures of two or more polyetherdiols
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polyurethanes Or Polyureas (AREA)
Abstract
A trimodal molecular weight toluene diisocyanate endcapped polyether polyol prepolymer is disclosed having free toluene diisocyanate below 0.5 weight percent where the three molecular weight polyols used are 300-800, 800 to 1500 and 1500-10000. Processes to make and use these prepolymers as polyurethane castable elastomers having exceptionally long flex fatigue lives using environmentally friendly materials essentially free of TDI are also disclosed.
Description
CA 0223~92 1998-04-22 TRIMODI~L MOLFCULAR WEIGHT POLYETHER POLYOL PREPOLYMERS
Field o~ the Invention This invention relates to curing poiyurethane elastomers with certain curatives reacted with prepolymers of polyether polyols reacted with multifunctional isocyanate. In particular, a urethane made of polyether polyols having three distinctly different molecular weights and prepared from a prepolymer having a reduce~ ree Lo~uene diisocyanate monomer content which are used to make the urethane elastomer. The urethanes of this invention have particular use in the manufacture of urethane products requiring very high flex fatigue resistance such as belts, automotive and industrial products and non-pneumatic tires.
Background of the Invention Urethanes have been used in the manufacture of solid tires useful for such applications as industrial tires, off-the-road tires, bicycles tires and the like. They have not been entirely satisfactory in such applications because such urethane solid tires do not have the proper cushioning and handling characteristics for a soft vehicle ride on such applications as passenger vehicles. Also, such solid tires suffer from internal heat build-up and subsequent degradation of the elastomer material in prolonged high speed service conditions or under rough terrain situations where the tire is being deformed.
Various polyurethane elastomers have been proposed for use on such solid tires, as described in U.S. patent 4,g34,425, owned by the same assignee, in which there is provided a non-pneumatic tire rotatable about an axis, having improved hysteresis and flex fatigue resistance.
~ The invention described above and taught in US 4,934,425 was based on the use of a polyether polyol prepolymer having a terminal functional group containing active hydrogen capable of reacting with an isocyanate group. For commercial application, prepolymers using toluene diisocyanate are manufactured. These prepolymers have come into CA 0223~92 1998-04-22 recent disfavor from an environmental and safety standpoint, because TDI
is volatile and thus requires special handling procedures. Another drawback to the use of TDI is that free TDI remains in the prepolymer and unless extracted, it is too reactive for use with many common chain extenders except those with very low reactivities.
Attempts to use lower levels of TDI yet maintain the high flex fatigue resistance properties have to date been unsuccessful.
Prepolymers prepared accordirlg to ~he teachings of G.B. ~,~01,410 wherein the TDI monomer content has been reduced to less than 0.5%
have greatly reduced flex fatigue properties. Such materials would not have the flex fatigue properties useful in non-pneumatic tire and other dynamic flex applications. When using the teachings of US Patent No.4,934,425 and reducing the TDI content below 0.5%, again greatly reduced flex fatigue properties result.
It is a further object of this invention to provide a urethane elastomer with flex fatigue properties equal to or better than those obtained when the prepolymer is formed by reacting binary polyols with a traditional isocyanate, with a corresponding level of free isocyanate.
It is a still further object of this invention to insure that the urethane so cured will be suitable for use in a non-pneumatic tire.
This invention surprisingly demonstrates the criticality of utilizing a specialized trimodal molecular weight urethane prepared from a prepolymer having a reduced free TDI monomer content with three distinct molecular weight peaks. These peaks and low residual 2~ isocyanate are both necessary to achieve high flex fatigue resistance.
The prepolymer is cured preferably with an organic diamine curative to yield a polyurethane elastomer providing the balance in properties required for good vehicle ride characteristics as well as long life.
SUMMARY OF THE INVENTION
This invention provides a trimodal MW prepolymer having residual free toluene diisocyanate below 0.~ %, the prepolymer comprising a first CA 0223~92 1998-04-22 D-6263 REPLACEMENT IjAGE ' ~ 77 ~ 7 . .
isocyanate end capped low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight isocyanate end capped polyether polyol having a molecular weight above 800 and below 1,500 and a third high molecular weight isocyanate end capped polyether polyol having a molecular weight between 1,500 and 10,000. These specialized prepolymers can then be cured or chain extended with an aromatic diamine curative to form a urethane elastomer composition. Polyurethane articles of manufacture, made preferably via castable urethane technology, are the intended primary utility of these described prepolymers and cured elastomers. These articles have a body made of the elastomer of this invention and may take the form of any article conventionally made of polyurethane or other elastomers or rubbers.
It will be shown from the following examples that when using the trimodal molecular weight prepolymers produced by the teachings of this invention, the dual advantages of low free TDI and superior flex fatigue properties result. These advantages are significant due to the higher quality, better performing product and the decreased pollution, mimimal worker exposure to reactive compositions, and environmental advantages.
DETAILED DESCRIPTION OF THE INVENTION
The invention resides in the specific selection of a polyether polyol prepolymer for the urethane elastomer which has at least three distinct molecular weight polyols having a reduced free TDI monomer content which may be further chain extended (cured) to form a polyurethane elastomer with exceptional flex fatigue life.
The polyether used in this invention is a polyether having a terminal functional group containing active hydrogen capable of reacting with an isocyanate group consisting of hydroxyl group.
Moreover, a pre-extended polymer obtained by reaction between a A~ S~
-CA 0223~92 1998-04-22 - D-6263 REPLACEMENT l'AG~
. .
Iow molecular weight polymer and a diisocyanate or a product obtained by reaction between prepolymer and diol compound may be used in this invention .
Polyethers used in this invention are an alkylene glycol such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol and the like, polyalkylene triol such as polypropylene triol, more preferably polytetramethylene ether glycol and its pre-extended polymer.
In this invention, a mixture of three or more different kinds of polyethers having molecular weights which are different from each other must be used. In this case, it is essential that at least one peak is located at the lower molecular weight region (from 300 to below 800), at least one peak is located in the intermediate molecular weight region (from 800 to 1500), and at least one peak is located in the higher molecular weight region (from above 1 500 to 1 0,000) .
Polytetramethylene ether glycol (PTMEG) is the most preferred polyol of the invention. A first low molecular weight polyether glycol is utilized having a molecular weight of above 300 and below 800. The essential second intermediate molecular weight polyether glycol has a molecular weight above 800 and below 1500 and a third higher molecular weight polyether glycol has a molecular weight between 1,500 and 5,000.
A more preferred range for the low molecular weight material is from between 400 and 700. For the intermediate molecular weight second glycol a more preferred molecular weight range is from 800 to 1 100. For the higher molecular weight third glycol, more preferred is below 2,000 to 4,500.
The most preferred range is a low molecular weight glycol of 650 molecular weight, an intermediate molecular weight glycol of ~N~Et,~D.r~ S~EET
CA 0223~92 1998-04-22 '- ' ~ . ;
D-6263 REPLACEMENT ~AGE
1000 molecular weight and a higher molecular weight glycol of 2,000.
The molar percent of the first glycol (that of low molecular weight) may be from 5 to 50. The molar percent of the second (that of intermediate weight) may be from 10 to 90. The molar percent of the third (that of higher weight) may be from 5 to 50.
The more preferred molar percents for the low, intermediate, and high molecular weight glycols are from 20 to 50 for the low, 30 to 70 for the intermediate, and 5 to 20 for the high molecular weight glycols.
Still more preferred molar percents for the low, intermediate, and high molecular weight glycols are from 30 to 45 for the low, 50 to 60 for the intermediate, and 5 to 15 for the high molecular weight glycols.
The prepolymer for use in a tire or other article is formed by reacting the low, intermediate, and high molecular weight glycols set forth above with a multifunctional isocyanate. The more preferred are the toluene diisocyanates (TDI). The two most preferred materials are the 80/20 and 65/35 blend of the 2,4- and 2,6-toluene diisocyanate isomers.
The ratio of TDI to polyol is commonly expressed in the art as isocyanate to polyol ratio or simply NCO:OH ratio.
The isocyanate to polyol ratio may be in the range of 1.9:1.0 to 2.8:1Ø A more preferred ratio is 2.0:1.0 to 2.6:1Ø The most preferred ratio is from 2.1:1.0 to 2.5:1Ø The percentage of free NCO in the resulting prepolymer is also in common use for characterizing prepolymers .
Polyfunctional isocyanates used in this invention are not particularly limited, but are preferably aromatic and aliphatic diisocyanates and triisocyanates. Aromatic diisocyanates are, for example:
tolylene-2,4-diisocyanate;
tolylene-2,6-diisocyanate;
naphthalene-1, 5-diisocyanate;
diphenyl-4,4'-diisocyanate;
diphenylmethane-4,4'-diisocyanate;
A~Ft~0E0 SffE~T
CA 0223~592 1998-04-22 - D-6263 REPLACEMENT F'A(~
dibenzyl-4,4'-diisocyanate;
stilbene-4,4'-diisocyanate;
benzophenone-4,4'-diisocyanate;
and their derivatives substituted with alkyl alkoxy, halogen or nitro groups, e.g., 3,3'-dimethylphenyl-4,4'diisocyanate or 3,3'-dichlorodiphenylmethane diisocyanate, their mixtures, aliphatic diisocyanates, and triisoyanates. Among them, there may be preferably used: tolylene-2,4-diisocyanate;
tolylene-2, 6-diisocyanate;
naphthalene-1 ,5-diisocyanate;diphenyl-4,4'-diisocyanate;
1 0 diphenylmethane-4,4'-diisocyanate; 1,6-hexamethylene diisocyanate; 1 ,3 and 1,4-cyclohexyl diisocyanate; methylenebisl4-cyclohexyldiisocyanate); 1,3- and 1,4-xylene diisocyanate and their mixtures.
The diisocyanate/polyol prepolymer, once reacted must be stripped to remove unreacted TDI or other volatile isocyanates as described above. Many methods of removing unreacted TDI monomer have been documented. Included in the literature are the use of molecular sieves, solvent extraction, and vacuum distillation, most notably thin film evaporation as described in G.B. 1,101,410.When considering a method for removal of free TDI, the occurrence of undesired side reactions which may occur at high temperatures should be considered.
The prepolymers of this invention may also be blends of three separately prepared isocyanate endcapped polyol prepolymers which have had the free isocyanate removed prior to blending or subsequent to the blending step in whichcase each of the prepolymers may have free toluene diisocyanate level of greaterthan 0.5 weight percent. The term "molecular weight" when used herein shall refer to number average molecular weight. The three separate prepolymers would have the molecular weight ranges indicated above, ie. the first low molecular weight isocyanate endcapped polyether glycol made from the reaction of an isocyanate with a polyol having a molecular weight of above 300 and below 800 (ie glycol with TDI). The essential second intermediate molecular weight isocyanate endcapped polyether glycol made from the reaction of an isocyanate with a polyol (ie glycol AI~N~r, CA 0223~92 1998-04-22 WO 97/19123 PCT/~S96116961 with TDI) having a molecular weight of between 800 and 1500 and a third higher molecular weight isocyanate endcapped polyether glycol made from the reaction of an isocyanate with a polyol ~ie glycol with TDI) having a molecular weight between 1,500 and 10,000. Regardless of how the trimodal molecular weight prepolymers are produced they must be chain extended or cured to provide useful polyurethane/urea elastomers.
The curing ayerlts of tl1is invention May be ~romatic or aliphatic polyamines or polyols as are conventionally used for the purpose.
Aromatic diamines are, for example, 4,4'methylene bis(2-chloroaniline), 2,2',5-trichloro-4,4'-methylenediamines, napthalene-1,5- diamine, ortho, meta, paraphenylenediamine, tolylene-2,4-diamine, dichlorobenzidine, diphenylether-4,4'-diamine, their derivatives and mixtures.
Among them there are preferably employed 4,4'methylene bis 2-chloroaniline, methylene dianiline, trimethyl bis(p-amino benzoate), bis amino phenylthioethane, napthalene-1,5-diamine, dichlorobenzidine, diphenylether, 4,4'-diamine, hydrazine, ethylenediamine, hexamethylene-1,6-diamine, piperazine, ethylene glycol, 1,3-propylene glycol, 1,3 and 1,4-butane diol, trimethyipropane and their mixtures.
The final urethane elastomer is cured using aromatic organic diamines which are well-known and commercially available. The more preferred material is 4,4'- methylene bis(2-chloroaniline) which will sometimes be referred to by its common names MOCA or MBOCA. Also preferred is the diethyl toluene diamine (DETDA) which is available commercially from Ethyl Corporation under the trade name Ethacure 100.
A suitable material which has a different cure rate is methylenedianiline-NaCI complex, commercially available from Uniroyal Chemical Company, Inc. as Caytur. The most preferred curative is 4,4'-methylene bis(2-chloroaniline).
The stoichiometry of the prepolymer to curative is expressed on a molar equivalence basis, hereinafter called equivalence ratio, rather than CA 0223~92 1998-04-22 D-6263 REPLACEMENT PA~
. .
on a weight basis. The broadest practical equivalence ratio of TDI-based prepolymer to curative is 80 to 1 15. More preferred is 95 to 1 10.
Most preferred is 100 to 105. The equivalence ratio is also commonly called - percent of theory - or simply stoichiometry.
It has been found through a long process of experimentation that several dynamic properties of elastomers must be carefully evaluated together in order to produce an elastomer suitable for the annular elastomeric body of the tire of this invention. A measure of dynamic modulus must reveal that the chosen elastomeric material has a relatively constant dynamic modulus over a wide temperature range. The tendency of the elastomer to build up internal heat due to elastic inefficiency is commonly called hysteresis in the industry. The hysteresis is commonly expressed in terms of a value obtained from a hysteresis-type test which is commonly described as tangent delta or, more commonly, tan ~. The tan ~ should show a decrease with a rise in temperature, indicating little internal heat build-up is occurring in the elastomeric body of article being tested.
The flex fatigue test helps measure the ability of the elastomer to withstand the millions of cycles to which a non-pneumatic tire may be subjected. The test which has been found to correlate favorably with actual test tires is the cut growth resistance as run in accordance with ASTM D-3629-78. Test conditions are: temperature 700C, atmosphere is air, rate of rotation is 500 rpm and elongation is 29%. The device utilized is the TEXUS Flex tester available from Testing Machines, Inc., New York, Model No. 31-1 1.
Dynamic measurements to determine a tan ~ value are useful to assure that a suitably low hysteresis value is obtained for the material.
Several hysteresis devices are useful including the Rheovibran Tester, Hysterometer, and the Rheometrics Viscoelastic Tester for Solids, Model RVE-S, made by Rheometrics, Inc., New Jersey. These instruments A~ S~rFI
CA 0223~92 1998-04-22 D-6263 REPLACEMENT F'AGE
- S -. .
impose a sinusoidal shear strain to the specimen, and analyze the torque responses and phase relation to the strain. The ultimate test of the suitability of an elastomer for use in a high speed tire is its ability to resist heat build-up and degradation at prolonged high speed service.
The following examples are for illustrative purposes only and are not meant to limit the scope of this invention in any manner whatsoever.
Comparative Examples A-G and Examples 1 and 2 of the invention The prepolymer of Comparative example A was prepared by reacting 2 moles of toluene diisocyanate with one mole of polytetramethylene ether glycol. Prepolymer of Comparative example B
was prepared by reacting 2.4 moles of toluene diisocyanate (TDI) with one mole of polytetramethylene ether glycol, after which the residual free TDI is removed in the manner described in G.B. 1,101,410.
These prepolymers were then reacted with the diamine methylene bis ortho chloroaniline (abbreviated MBOCA) at an isocyanate to active hydrogen ratio of 1.05:1, cured for 16 hours at 100~C (212~F) and allowed to equilibrate for 7 days at ambient conditions. Texus flex measurements were then taken. It was found that Texus flex longevity is reduced when the excess free residual TDI is removed. These results are reported in Table 1.
The prepolymers of Comparative examples C, D, E and F were prepared in accordance with the teachings of US Patent No. 4,934,435 wherein for Example C a molar ratio of 2.15:1 TDI to a polytetramethylene ether glycol (PTMEG) mixture of 85:15 mole ratio 1000:2000 molecular weights. This prepolymer may also be prepared from a mixture of a toluene diisocyanate polytetramethylene ether glycol 2000 molecular weight prepolymer and a toluene diisocyanate polytetramethylene ether glycol 1000 molecular weight prepolymer on a 8 5 :1 5 molar ratio.
HEFr CA 0223~592 1998-04-22 D-6263 REPLACEMENT PAG~
For examples D through F, an excess amount of TDI was used and the 1000 and 2000 molecular weight polytetramethylene ether glycols are preblended prior to forming the prepolymer with TDI. For example D, an excess amount of TDI was used with a 2.4: 1 ratio of the two molecular weight glycols to achieve a 6.2% isocyanate content after the excess TDI was removed.
Example E was prepared using a molar ratio of 2.05:1 TDI to PTMEG of 70:30 650 to 2000 molecular weight. The prepolymer of Example F was prepared using a 2.4 moles of TDI to 1 mole of a PTMEG mixture of 70:30 mole ratio 650 to 2000 molecular weight. The residual free remaining toluene 1 0 diisocyanate was removed.
These prepolymers were then reacted with MBOCA at an isocyanate to active hydrogen ratio 1.05 and then cured 16 hours at 100~C (212~F). They were allowed to equilibrate for seven days at ambient conditions. Texus flex measurements were then taken. Again, it was found in both cases that Texus 1 5 flex longevity was reduced when free residual toluene diisocyanate levels were reduced .
In Comparative Example G, a ternary blend of polytetramethylene ether glycols of 36:48:15 mole ratio of 650:1000:2000 molecular weight was reacted with 2.05 moles of toluene diisocyanate per mole of mixture.
Examples 1 and 2 of the invention In Examples 1 and 2, the prepolymers were prepared using 2.4 moles of toluene diisocyanate per mole of the appropriate ternary blend of polytetramethylene ether glycol. In Example 1 the ratio was 31:62:7 moles of 650:1000:2000 molecular weight polyols. For Example 2 the ratio was 36:57:7 of the 650:1000:2900 molecular weight polyols. The free toluene diisocyanate was then removed.
The prepolymers of Examples G, 1 and 2 were reacted with MBOCA at an isocyanate to active hydrogen ratio of 1.05:1, cured for 16 hours at 100~C
(21 2~F), and allowed to equilibrate for seven days at ambient conditions. The TEXUS FLEX measurements were taken as described AM'N~O S~EFI
CA 0223~92 1998-04-22 WO97/19123 PCT~S96/16961 above and are reported in Table 1.
Example # Molecular Wt ~NCO Free TDI Texus Flex CYcle6 A 1000 6.3 3.4 5M
B 1000 6.3 0.1 2M
C 2000/1000 6.3 3.4 85~
D 2000/1000 6.2 0.1 25M
E 2000/650 6.4 3.2182M
F 2000/6~0 6.0 0.2 75M
G 2000/1000/650 6.4 3.2 58M
1 2000/1000/650 6.0 0.2 158M
2 2900/1000/650 6.0 0.2 182M
It can be seen from the Table that the ternary molecular weight polyol mixtures of conventional prepolymers, with traditional levels of free TDI, are not improved beyond the prior art as might be expected.
Surprisingly, however, low free TDI materials improve dramatically in Texus flex cycles. This result combines the environmental advantages of low free TDI materials with the endurance needed for service life of the end products manufactured from the resins made according to the teachings of this invention.
COMMERCIAL APPLICABILITY
This invention resides in the recognition of the superior performance provided by this specific polyether urethane chemistry.
Polyurethane articles of manufacture, made preferably via castable urethane technology, are the intended primary utility of these described prepolymers and cured elastomers. These articles have a body made of the elastomer of this invention and may take the form of any article CA 0223~92 1998-04-22 D-6263 REPLACEMENT FAGE . ' ~ ' I
. .
conventionally made of polyurethane or other elastomers or rubbers such as a belt, hose, air spring, shoe sole, shoe heel, small or large elastomeric-containing wheel assemblies (ie skate wheels, industrial tires, automotive-type elastomers and tires. Any article needing improved dynamic flex life (improved flex fatigue resistance) can benefit from the elastomers of this invention.
A preferred end use of this chemistry is a tire which is non-pneumatic in character but which can perform on the highway with durability and vehicle handling characteristics similar to a pneumatic tire.
The non-pneumatic tire described in U.S. Pat 4,934,425, the disclosure of which is hereby incorporated by reference, would be a most preferred use of the prepolymer and polyurethane elastomer materials of the instant invention. This embodiment encompasses a non-pneumatic tire rotatable about an axis, having improved hysteresis and flex fatigue resistance comprising: an annular body of resilient polyether urethane elastomeric material formed of a first isocyanate end capped low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight isocyanate end capped polyether polyol having a molecular weight above 800 and below 1,500 and a third higher molecular weight isocyanate end capped polyether polyol having a molecular weight between 1,500 and 10,000 cured with an aromatic diamine curative. In a further specialized embodiment the forgoing trimodal prepolymer and elastomer are used to make the annular body of the device of U.S. Patent No, 4,934,425, which discloses a tire structure having an annular body having a generally cylindrical outer member at the outer periphery thereof, a generally cylindrical inner member spaced radially inward from and coaxial with said outer member, a plurality of axially extending, circumferentially spaced-apart rib members connected at their corresponding inner and outer ends to said inner and outer cylindrical members, said rib members being generally inclined at an angle of about Oo to 75O to radial planes which intersect them at their ~~~r3 s~
CA 0223~92 1998-04-22 - 1:~- ' ' '' .
. .
inner ends, and at least one web member having opposite side faces, said web member having its inner and outer peripheries connected respectively to said inner and outer cylindrical members, said web member being connected on at least one of its side faces to at least one of said rib members to thereby form with said rib member a load-carrying structure for said outer cylindrical member, said load carrying structure being constructed to permit locally loaded members to buckle.
~ ,~0~3~C~T
Field o~ the Invention This invention relates to curing poiyurethane elastomers with certain curatives reacted with prepolymers of polyether polyols reacted with multifunctional isocyanate. In particular, a urethane made of polyether polyols having three distinctly different molecular weights and prepared from a prepolymer having a reduce~ ree Lo~uene diisocyanate monomer content which are used to make the urethane elastomer. The urethanes of this invention have particular use in the manufacture of urethane products requiring very high flex fatigue resistance such as belts, automotive and industrial products and non-pneumatic tires.
Background of the Invention Urethanes have been used in the manufacture of solid tires useful for such applications as industrial tires, off-the-road tires, bicycles tires and the like. They have not been entirely satisfactory in such applications because such urethane solid tires do not have the proper cushioning and handling characteristics for a soft vehicle ride on such applications as passenger vehicles. Also, such solid tires suffer from internal heat build-up and subsequent degradation of the elastomer material in prolonged high speed service conditions or under rough terrain situations where the tire is being deformed.
Various polyurethane elastomers have been proposed for use on such solid tires, as described in U.S. patent 4,g34,425, owned by the same assignee, in which there is provided a non-pneumatic tire rotatable about an axis, having improved hysteresis and flex fatigue resistance.
~ The invention described above and taught in US 4,934,425 was based on the use of a polyether polyol prepolymer having a terminal functional group containing active hydrogen capable of reacting with an isocyanate group. For commercial application, prepolymers using toluene diisocyanate are manufactured. These prepolymers have come into CA 0223~92 1998-04-22 recent disfavor from an environmental and safety standpoint, because TDI
is volatile and thus requires special handling procedures. Another drawback to the use of TDI is that free TDI remains in the prepolymer and unless extracted, it is too reactive for use with many common chain extenders except those with very low reactivities.
Attempts to use lower levels of TDI yet maintain the high flex fatigue resistance properties have to date been unsuccessful.
Prepolymers prepared accordirlg to ~he teachings of G.B. ~,~01,410 wherein the TDI monomer content has been reduced to less than 0.5%
have greatly reduced flex fatigue properties. Such materials would not have the flex fatigue properties useful in non-pneumatic tire and other dynamic flex applications. When using the teachings of US Patent No.4,934,425 and reducing the TDI content below 0.5%, again greatly reduced flex fatigue properties result.
It is a further object of this invention to provide a urethane elastomer with flex fatigue properties equal to or better than those obtained when the prepolymer is formed by reacting binary polyols with a traditional isocyanate, with a corresponding level of free isocyanate.
It is a still further object of this invention to insure that the urethane so cured will be suitable for use in a non-pneumatic tire.
This invention surprisingly demonstrates the criticality of utilizing a specialized trimodal molecular weight urethane prepared from a prepolymer having a reduced free TDI monomer content with three distinct molecular weight peaks. These peaks and low residual 2~ isocyanate are both necessary to achieve high flex fatigue resistance.
The prepolymer is cured preferably with an organic diamine curative to yield a polyurethane elastomer providing the balance in properties required for good vehicle ride characteristics as well as long life.
SUMMARY OF THE INVENTION
This invention provides a trimodal MW prepolymer having residual free toluene diisocyanate below 0.~ %, the prepolymer comprising a first CA 0223~92 1998-04-22 D-6263 REPLACEMENT IjAGE ' ~ 77 ~ 7 . .
isocyanate end capped low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight isocyanate end capped polyether polyol having a molecular weight above 800 and below 1,500 and a third high molecular weight isocyanate end capped polyether polyol having a molecular weight between 1,500 and 10,000. These specialized prepolymers can then be cured or chain extended with an aromatic diamine curative to form a urethane elastomer composition. Polyurethane articles of manufacture, made preferably via castable urethane technology, are the intended primary utility of these described prepolymers and cured elastomers. These articles have a body made of the elastomer of this invention and may take the form of any article conventionally made of polyurethane or other elastomers or rubbers.
It will be shown from the following examples that when using the trimodal molecular weight prepolymers produced by the teachings of this invention, the dual advantages of low free TDI and superior flex fatigue properties result. These advantages are significant due to the higher quality, better performing product and the decreased pollution, mimimal worker exposure to reactive compositions, and environmental advantages.
DETAILED DESCRIPTION OF THE INVENTION
The invention resides in the specific selection of a polyether polyol prepolymer for the urethane elastomer which has at least three distinct molecular weight polyols having a reduced free TDI monomer content which may be further chain extended (cured) to form a polyurethane elastomer with exceptional flex fatigue life.
The polyether used in this invention is a polyether having a terminal functional group containing active hydrogen capable of reacting with an isocyanate group consisting of hydroxyl group.
Moreover, a pre-extended polymer obtained by reaction between a A~ S~
-CA 0223~92 1998-04-22 - D-6263 REPLACEMENT l'AG~
. .
Iow molecular weight polymer and a diisocyanate or a product obtained by reaction between prepolymer and diol compound may be used in this invention .
Polyethers used in this invention are an alkylene glycol such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol and the like, polyalkylene triol such as polypropylene triol, more preferably polytetramethylene ether glycol and its pre-extended polymer.
In this invention, a mixture of three or more different kinds of polyethers having molecular weights which are different from each other must be used. In this case, it is essential that at least one peak is located at the lower molecular weight region (from 300 to below 800), at least one peak is located in the intermediate molecular weight region (from 800 to 1500), and at least one peak is located in the higher molecular weight region (from above 1 500 to 1 0,000) .
Polytetramethylene ether glycol (PTMEG) is the most preferred polyol of the invention. A first low molecular weight polyether glycol is utilized having a molecular weight of above 300 and below 800. The essential second intermediate molecular weight polyether glycol has a molecular weight above 800 and below 1500 and a third higher molecular weight polyether glycol has a molecular weight between 1,500 and 5,000.
A more preferred range for the low molecular weight material is from between 400 and 700. For the intermediate molecular weight second glycol a more preferred molecular weight range is from 800 to 1 100. For the higher molecular weight third glycol, more preferred is below 2,000 to 4,500.
The most preferred range is a low molecular weight glycol of 650 molecular weight, an intermediate molecular weight glycol of ~N~Et,~D.r~ S~EET
CA 0223~92 1998-04-22 '- ' ~ . ;
D-6263 REPLACEMENT ~AGE
1000 molecular weight and a higher molecular weight glycol of 2,000.
The molar percent of the first glycol (that of low molecular weight) may be from 5 to 50. The molar percent of the second (that of intermediate weight) may be from 10 to 90. The molar percent of the third (that of higher weight) may be from 5 to 50.
The more preferred molar percents for the low, intermediate, and high molecular weight glycols are from 20 to 50 for the low, 30 to 70 for the intermediate, and 5 to 20 for the high molecular weight glycols.
Still more preferred molar percents for the low, intermediate, and high molecular weight glycols are from 30 to 45 for the low, 50 to 60 for the intermediate, and 5 to 15 for the high molecular weight glycols.
The prepolymer for use in a tire or other article is formed by reacting the low, intermediate, and high molecular weight glycols set forth above with a multifunctional isocyanate. The more preferred are the toluene diisocyanates (TDI). The two most preferred materials are the 80/20 and 65/35 blend of the 2,4- and 2,6-toluene diisocyanate isomers.
The ratio of TDI to polyol is commonly expressed in the art as isocyanate to polyol ratio or simply NCO:OH ratio.
The isocyanate to polyol ratio may be in the range of 1.9:1.0 to 2.8:1Ø A more preferred ratio is 2.0:1.0 to 2.6:1Ø The most preferred ratio is from 2.1:1.0 to 2.5:1Ø The percentage of free NCO in the resulting prepolymer is also in common use for characterizing prepolymers .
Polyfunctional isocyanates used in this invention are not particularly limited, but are preferably aromatic and aliphatic diisocyanates and triisocyanates. Aromatic diisocyanates are, for example:
tolylene-2,4-diisocyanate;
tolylene-2,6-diisocyanate;
naphthalene-1, 5-diisocyanate;
diphenyl-4,4'-diisocyanate;
diphenylmethane-4,4'-diisocyanate;
A~Ft~0E0 SffE~T
CA 0223~592 1998-04-22 - D-6263 REPLACEMENT F'A(~
dibenzyl-4,4'-diisocyanate;
stilbene-4,4'-diisocyanate;
benzophenone-4,4'-diisocyanate;
and their derivatives substituted with alkyl alkoxy, halogen or nitro groups, e.g., 3,3'-dimethylphenyl-4,4'diisocyanate or 3,3'-dichlorodiphenylmethane diisocyanate, their mixtures, aliphatic diisocyanates, and triisoyanates. Among them, there may be preferably used: tolylene-2,4-diisocyanate;
tolylene-2, 6-diisocyanate;
naphthalene-1 ,5-diisocyanate;diphenyl-4,4'-diisocyanate;
1 0 diphenylmethane-4,4'-diisocyanate; 1,6-hexamethylene diisocyanate; 1 ,3 and 1,4-cyclohexyl diisocyanate; methylenebisl4-cyclohexyldiisocyanate); 1,3- and 1,4-xylene diisocyanate and their mixtures.
The diisocyanate/polyol prepolymer, once reacted must be stripped to remove unreacted TDI or other volatile isocyanates as described above. Many methods of removing unreacted TDI monomer have been documented. Included in the literature are the use of molecular sieves, solvent extraction, and vacuum distillation, most notably thin film evaporation as described in G.B. 1,101,410.When considering a method for removal of free TDI, the occurrence of undesired side reactions which may occur at high temperatures should be considered.
The prepolymers of this invention may also be blends of three separately prepared isocyanate endcapped polyol prepolymers which have had the free isocyanate removed prior to blending or subsequent to the blending step in whichcase each of the prepolymers may have free toluene diisocyanate level of greaterthan 0.5 weight percent. The term "molecular weight" when used herein shall refer to number average molecular weight. The three separate prepolymers would have the molecular weight ranges indicated above, ie. the first low molecular weight isocyanate endcapped polyether glycol made from the reaction of an isocyanate with a polyol having a molecular weight of above 300 and below 800 (ie glycol with TDI). The essential second intermediate molecular weight isocyanate endcapped polyether glycol made from the reaction of an isocyanate with a polyol (ie glycol AI~N~r, CA 0223~92 1998-04-22 WO 97/19123 PCT/~S96116961 with TDI) having a molecular weight of between 800 and 1500 and a third higher molecular weight isocyanate endcapped polyether glycol made from the reaction of an isocyanate with a polyol ~ie glycol with TDI) having a molecular weight between 1,500 and 10,000. Regardless of how the trimodal molecular weight prepolymers are produced they must be chain extended or cured to provide useful polyurethane/urea elastomers.
The curing ayerlts of tl1is invention May be ~romatic or aliphatic polyamines or polyols as are conventionally used for the purpose.
Aromatic diamines are, for example, 4,4'methylene bis(2-chloroaniline), 2,2',5-trichloro-4,4'-methylenediamines, napthalene-1,5- diamine, ortho, meta, paraphenylenediamine, tolylene-2,4-diamine, dichlorobenzidine, diphenylether-4,4'-diamine, their derivatives and mixtures.
Among them there are preferably employed 4,4'methylene bis 2-chloroaniline, methylene dianiline, trimethyl bis(p-amino benzoate), bis amino phenylthioethane, napthalene-1,5-diamine, dichlorobenzidine, diphenylether, 4,4'-diamine, hydrazine, ethylenediamine, hexamethylene-1,6-diamine, piperazine, ethylene glycol, 1,3-propylene glycol, 1,3 and 1,4-butane diol, trimethyipropane and their mixtures.
The final urethane elastomer is cured using aromatic organic diamines which are well-known and commercially available. The more preferred material is 4,4'- methylene bis(2-chloroaniline) which will sometimes be referred to by its common names MOCA or MBOCA. Also preferred is the diethyl toluene diamine (DETDA) which is available commercially from Ethyl Corporation under the trade name Ethacure 100.
A suitable material which has a different cure rate is methylenedianiline-NaCI complex, commercially available from Uniroyal Chemical Company, Inc. as Caytur. The most preferred curative is 4,4'-methylene bis(2-chloroaniline).
The stoichiometry of the prepolymer to curative is expressed on a molar equivalence basis, hereinafter called equivalence ratio, rather than CA 0223~92 1998-04-22 D-6263 REPLACEMENT PA~
. .
on a weight basis. The broadest practical equivalence ratio of TDI-based prepolymer to curative is 80 to 1 15. More preferred is 95 to 1 10.
Most preferred is 100 to 105. The equivalence ratio is also commonly called - percent of theory - or simply stoichiometry.
It has been found through a long process of experimentation that several dynamic properties of elastomers must be carefully evaluated together in order to produce an elastomer suitable for the annular elastomeric body of the tire of this invention. A measure of dynamic modulus must reveal that the chosen elastomeric material has a relatively constant dynamic modulus over a wide temperature range. The tendency of the elastomer to build up internal heat due to elastic inefficiency is commonly called hysteresis in the industry. The hysteresis is commonly expressed in terms of a value obtained from a hysteresis-type test which is commonly described as tangent delta or, more commonly, tan ~. The tan ~ should show a decrease with a rise in temperature, indicating little internal heat build-up is occurring in the elastomeric body of article being tested.
The flex fatigue test helps measure the ability of the elastomer to withstand the millions of cycles to which a non-pneumatic tire may be subjected. The test which has been found to correlate favorably with actual test tires is the cut growth resistance as run in accordance with ASTM D-3629-78. Test conditions are: temperature 700C, atmosphere is air, rate of rotation is 500 rpm and elongation is 29%. The device utilized is the TEXUS Flex tester available from Testing Machines, Inc., New York, Model No. 31-1 1.
Dynamic measurements to determine a tan ~ value are useful to assure that a suitably low hysteresis value is obtained for the material.
Several hysteresis devices are useful including the Rheovibran Tester, Hysterometer, and the Rheometrics Viscoelastic Tester for Solids, Model RVE-S, made by Rheometrics, Inc., New Jersey. These instruments A~ S~rFI
CA 0223~92 1998-04-22 D-6263 REPLACEMENT F'AGE
- S -. .
impose a sinusoidal shear strain to the specimen, and analyze the torque responses and phase relation to the strain. The ultimate test of the suitability of an elastomer for use in a high speed tire is its ability to resist heat build-up and degradation at prolonged high speed service.
The following examples are for illustrative purposes only and are not meant to limit the scope of this invention in any manner whatsoever.
Comparative Examples A-G and Examples 1 and 2 of the invention The prepolymer of Comparative example A was prepared by reacting 2 moles of toluene diisocyanate with one mole of polytetramethylene ether glycol. Prepolymer of Comparative example B
was prepared by reacting 2.4 moles of toluene diisocyanate (TDI) with one mole of polytetramethylene ether glycol, after which the residual free TDI is removed in the manner described in G.B. 1,101,410.
These prepolymers were then reacted with the diamine methylene bis ortho chloroaniline (abbreviated MBOCA) at an isocyanate to active hydrogen ratio of 1.05:1, cured for 16 hours at 100~C (212~F) and allowed to equilibrate for 7 days at ambient conditions. Texus flex measurements were then taken. It was found that Texus flex longevity is reduced when the excess free residual TDI is removed. These results are reported in Table 1.
The prepolymers of Comparative examples C, D, E and F were prepared in accordance with the teachings of US Patent No. 4,934,435 wherein for Example C a molar ratio of 2.15:1 TDI to a polytetramethylene ether glycol (PTMEG) mixture of 85:15 mole ratio 1000:2000 molecular weights. This prepolymer may also be prepared from a mixture of a toluene diisocyanate polytetramethylene ether glycol 2000 molecular weight prepolymer and a toluene diisocyanate polytetramethylene ether glycol 1000 molecular weight prepolymer on a 8 5 :1 5 molar ratio.
HEFr CA 0223~592 1998-04-22 D-6263 REPLACEMENT PAG~
For examples D through F, an excess amount of TDI was used and the 1000 and 2000 molecular weight polytetramethylene ether glycols are preblended prior to forming the prepolymer with TDI. For example D, an excess amount of TDI was used with a 2.4: 1 ratio of the two molecular weight glycols to achieve a 6.2% isocyanate content after the excess TDI was removed.
Example E was prepared using a molar ratio of 2.05:1 TDI to PTMEG of 70:30 650 to 2000 molecular weight. The prepolymer of Example F was prepared using a 2.4 moles of TDI to 1 mole of a PTMEG mixture of 70:30 mole ratio 650 to 2000 molecular weight. The residual free remaining toluene 1 0 diisocyanate was removed.
These prepolymers were then reacted with MBOCA at an isocyanate to active hydrogen ratio 1.05 and then cured 16 hours at 100~C (212~F). They were allowed to equilibrate for seven days at ambient conditions. Texus flex measurements were then taken. Again, it was found in both cases that Texus 1 5 flex longevity was reduced when free residual toluene diisocyanate levels were reduced .
In Comparative Example G, a ternary blend of polytetramethylene ether glycols of 36:48:15 mole ratio of 650:1000:2000 molecular weight was reacted with 2.05 moles of toluene diisocyanate per mole of mixture.
Examples 1 and 2 of the invention In Examples 1 and 2, the prepolymers were prepared using 2.4 moles of toluene diisocyanate per mole of the appropriate ternary blend of polytetramethylene ether glycol. In Example 1 the ratio was 31:62:7 moles of 650:1000:2000 molecular weight polyols. For Example 2 the ratio was 36:57:7 of the 650:1000:2900 molecular weight polyols. The free toluene diisocyanate was then removed.
The prepolymers of Examples G, 1 and 2 were reacted with MBOCA at an isocyanate to active hydrogen ratio of 1.05:1, cured for 16 hours at 100~C
(21 2~F), and allowed to equilibrate for seven days at ambient conditions. The TEXUS FLEX measurements were taken as described AM'N~O S~EFI
CA 0223~92 1998-04-22 WO97/19123 PCT~S96/16961 above and are reported in Table 1.
Example # Molecular Wt ~NCO Free TDI Texus Flex CYcle6 A 1000 6.3 3.4 5M
B 1000 6.3 0.1 2M
C 2000/1000 6.3 3.4 85~
D 2000/1000 6.2 0.1 25M
E 2000/650 6.4 3.2182M
F 2000/6~0 6.0 0.2 75M
G 2000/1000/650 6.4 3.2 58M
1 2000/1000/650 6.0 0.2 158M
2 2900/1000/650 6.0 0.2 182M
It can be seen from the Table that the ternary molecular weight polyol mixtures of conventional prepolymers, with traditional levels of free TDI, are not improved beyond the prior art as might be expected.
Surprisingly, however, low free TDI materials improve dramatically in Texus flex cycles. This result combines the environmental advantages of low free TDI materials with the endurance needed for service life of the end products manufactured from the resins made according to the teachings of this invention.
COMMERCIAL APPLICABILITY
This invention resides in the recognition of the superior performance provided by this specific polyether urethane chemistry.
Polyurethane articles of manufacture, made preferably via castable urethane technology, are the intended primary utility of these described prepolymers and cured elastomers. These articles have a body made of the elastomer of this invention and may take the form of any article CA 0223~92 1998-04-22 D-6263 REPLACEMENT FAGE . ' ~ ' I
. .
conventionally made of polyurethane or other elastomers or rubbers such as a belt, hose, air spring, shoe sole, shoe heel, small or large elastomeric-containing wheel assemblies (ie skate wheels, industrial tires, automotive-type elastomers and tires. Any article needing improved dynamic flex life (improved flex fatigue resistance) can benefit from the elastomers of this invention.
A preferred end use of this chemistry is a tire which is non-pneumatic in character but which can perform on the highway with durability and vehicle handling characteristics similar to a pneumatic tire.
The non-pneumatic tire described in U.S. Pat 4,934,425, the disclosure of which is hereby incorporated by reference, would be a most preferred use of the prepolymer and polyurethane elastomer materials of the instant invention. This embodiment encompasses a non-pneumatic tire rotatable about an axis, having improved hysteresis and flex fatigue resistance comprising: an annular body of resilient polyether urethane elastomeric material formed of a first isocyanate end capped low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight isocyanate end capped polyether polyol having a molecular weight above 800 and below 1,500 and a third higher molecular weight isocyanate end capped polyether polyol having a molecular weight between 1,500 and 10,000 cured with an aromatic diamine curative. In a further specialized embodiment the forgoing trimodal prepolymer and elastomer are used to make the annular body of the device of U.S. Patent No, 4,934,425, which discloses a tire structure having an annular body having a generally cylindrical outer member at the outer periphery thereof, a generally cylindrical inner member spaced radially inward from and coaxial with said outer member, a plurality of axially extending, circumferentially spaced-apart rib members connected at their corresponding inner and outer ends to said inner and outer cylindrical members, said rib members being generally inclined at an angle of about Oo to 75O to radial planes which intersect them at their ~~~r3 s~
CA 0223~92 1998-04-22 - 1:~- ' ' '' .
. .
inner ends, and at least one web member having opposite side faces, said web member having its inner and outer peripheries connected respectively to said inner and outer cylindrical members, said web member being connected on at least one of its side faces to at least one of said rib members to thereby form with said rib member a load-carrying structure for said outer cylindrical member, said load carrying structure being constructed to permit locally loaded members to buckle.
~ ,~0~3~C~T
Claims (10)
1. A process of making a trimodal molecular weight polyether polyol prepolymer having free toluene diisocyanate below 0.5 weight percent comprising the steps of:
a) reacting toluene diisocyanate with a long chain diol component comprising at least three distinct molecular weight (Mn) polyols, a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500 and a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000 to form an isocyanate end capped prepolymer; and b) removing unreacted toluene diisocyanate from the isocyanate end capped prepolymer to a level of less than 0.5 weight percent toluene diisocyanate.
a) reacting toluene diisocyanate with a long chain diol component comprising at least three distinct molecular weight (Mn) polyols, a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500 and a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000 to form an isocyanate end capped prepolymer; and b) removing unreacted toluene diisocyanate from the isocyanate end capped prepolymer to a level of less than 0.5 weight percent toluene diisocyanate.
2. A polyurethane elastomer formed by the reaction of an aromatic diamine curative with a trimodal molecular weight polyether polyol prepolymer having free volatile isocyanate below 0.5 weight percent and comprising at least three distinct molecular weight polyols, a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500 and a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000 to form an isocyanate end capped prepolymer.
3. A prepolymer obtainable by the process according to Claim 1 wherein said polyether polyols are polytetramethylene ether glycols.
4. A prepolymer obtainable by the process according to claim 3 wherein the first polytetramethylene ether glycol has a molecular weight of between 400 and 700, the second polytetramethylene ether glycol has a molecular weight between and 1100 and the third polytetramethylene ether glycol has a molecular weight between 2,000 and 4,500.
5. A polyurethane elastomer according to claim 2 wherein the polyether urethane elastomer has a molar equivalence ratio (moles of isocyanate end groups to moles of polyol groups) range of the first, second, and third isocyanate end capped glycol to aromatic diamine curative of 80 to 115.
6. A polyurethane elastomer according to claim 2 wherein the ratio of NCO to OH is in the range of 2.0:1.0 to 2.6:1Ø
7. A polyurethane elastomer according to claim 2 wherein the aromatic diamine curative is 4,4'-methylene bis(2-chloroaniline).
8. A process of making a trimodal molecular weight polyether polyol prepolymer having free toluene diisocyanate below 0.5 weight percent comprising the steps of:
(a) blending a first, a second and a third toluene diisocyanate endcapped polyol prepolymer, each of said prepolymers having a free toluene diisocyanate level of greater than 0.5 weight percent, said first toluene diisocyanate endcapped polyol prepolymer being the reaction product of toluene diisocyanate and a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800, said second toluene diisocyanate endcapped polyol prepolymer being the reaction product of toluene diisocyanate and a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500, said third toluene diisocyanate endcapped polyol prepolymer being the reaction product of toluene diisocyanate and a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000 to form a prepolymer blend; and b) removing unreacted toluene diisocyanate from the prepolymer blend to a level of less than 0.5 weight percent toluene diisocyanate.
(a) blending a first, a second and a third toluene diisocyanate endcapped polyol prepolymer, each of said prepolymers having a free toluene diisocyanate level of greater than 0.5 weight percent, said first toluene diisocyanate endcapped polyol prepolymer being the reaction product of toluene diisocyanate and a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800, said second toluene diisocyanate endcapped polyol prepolymer being the reaction product of toluene diisocyanate and a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500, said third toluene diisocyanate endcapped polyol prepolymer being the reaction product of toluene diisocyanate and a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000 to form a prepolymer blend; and b) removing unreacted toluene diisocyanate from the prepolymer blend to a level of less than 0.5 weight percent toluene diisocyanate.
9. A process of making a trimodal molecular weight polyether polyol prepolymer having free toluene diisocyanate below 0.5 weight percent comprising the steps of:
(a) producing a first toluene diisocyanate endcapped polyol prepolymer as the reaction product of toluene diisocyanate and a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800;
(b) producing a second toluene diisocyanate endcapped polyol prepolymer as the reaction product of toluene diisocyanate a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500;
(c) producing a third toluene diisocyanate endcapped polyol prepolymer as the reaction product of toluene diisocyanate a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000;
(d) removing unreacted toluene diisocyanate to a level of less than 0.5 weight percent toluene diisocyanate in each of said first, said second and said third toluene diisocyanate endcapped polyol prepolymer; and (e) blending said first, said second and said third toluene diisocyanate endcapped polyol prepolymer, each of said prepolymers having a free toluene diisocyanate level of less than 0.5 weight percent to make said trimodal molecular weight polyether polyol prepolymer.
(a) producing a first toluene diisocyanate endcapped polyol prepolymer as the reaction product of toluene diisocyanate and a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800;
(b) producing a second toluene diisocyanate endcapped polyol prepolymer as the reaction product of toluene diisocyanate a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500;
(c) producing a third toluene diisocyanate endcapped polyol prepolymer as the reaction product of toluene diisocyanate a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000;
(d) removing unreacted toluene diisocyanate to a level of less than 0.5 weight percent toluene diisocyanate in each of said first, said second and said third toluene diisocyanate endcapped polyol prepolymer; and (e) blending said first, said second and said third toluene diisocyanate endcapped polyol prepolymer, each of said prepolymers having a free toluene diisocyanate level of less than 0.5 weight percent to make said trimodal molecular weight polyether polyol prepolymer.
10. An elastomeric article having improved flex fatigue resistance comprising: a body of polyurethane elastomer formed by the reaction of an aromatic diamine curative with a trimodal molecular weight polyether polyol prepolymer having free volatile isocyanate below 0.5 weight percent and comprising at least three distinct molecular weight polyols, a first low molecular weight polyether polyol having a molecular weight of above 300 and below 800 and a second intermediate molecular weight polyether polyol having a molecular weight above 800 and below 1,500 and a third higher molecular weight polyether polyol having a molecular weight between 1,500 and 10,000 to form an isocyanate end capped prepolymer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/561,650 US5654390A (en) | 1995-11-17 | 1995-11-17 | Trimodal molecular weight polyether polyol prepolymers |
| US08/561,650 | 1995-11-17 | ||
| PCT/US1996/016961 WO1997019123A1 (en) | 1995-11-17 | 1996-11-01 | Trimodal molecular weight polyether polyol prepolymers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2235592A1 true CA2235592A1 (en) | 1997-05-29 |
Family
ID=24242853
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002235592A Abandoned CA2235592A1 (en) | 1995-11-17 | 1996-11-01 | Trimodal molecular weight polyether polyol prepolymers |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5654390A (en) |
| EP (1) | EP0861276B1 (en) |
| JP (1) | JP3073023B2 (en) |
| AU (1) | AU7518896A (en) |
| CA (1) | CA2235592A1 (en) |
| DE (1) | DE69620005T2 (en) |
| TW (1) | TW381103B (en) |
| WO (1) | WO1997019123A1 (en) |
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| BR9907699A (en) * | 1998-02-06 | 2002-01-15 | Union Carbide Chem Plastic | Polymeric compositions of alkylene oxide |
| US6174984B1 (en) * | 1999-06-14 | 2001-01-16 | Uniroyal Chemical Company, Inc. | Clear, resilient polyurethane elastomers |
| WO2002004536A2 (en) * | 2000-07-12 | 2002-01-17 | Uniroyal Chemical Company, Inc. | Modified urethane compositions containing adducts of o-phthalic anhydride ester polyols |
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| JP6929764B2 (en) * | 2017-12-01 | 2021-09-01 | Ｔｏｙｏ Ｔｉｒｅ株式会社 | Non-pneumatic tire |
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| CN114213621B (en) * | 2022-01-19 | 2023-06-06 | 美瑞新材料创新中心(山东)有限公司 | Bulk matte thermoplastic polyurethane elastomer material and preparation method and application thereof |
| CN114853980B (en) * | 2022-03-25 | 2023-05-23 | 华南理工大学 | Polyurethane prepolymer for crane wire rope carrier roller, polyurethane material and preparation method |
| CN115651593B (en) * | 2022-11-14 | 2023-09-22 | 湖南柯盛新材料有限公司 | Hot melt adhesive for bonding polyester rubber elastic material and polycarbonate elastic material, and preparation method and application thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1101410A (en) * | 1912-07-19 | 1914-06-23 | George W Cooper | Hand-pump. |
| US3798200A (en) * | 1972-12-13 | 1974-03-19 | Bridgestone Tire Co Ltd | Polyether urethane elastomer having an improved cut growth and flex crack resistance and the process for preparation thereof |
| JPS532199B2 (en) * | 1973-07-03 | 1978-01-26 | ||
| US3980606A (en) * | 1975-02-24 | 1976-09-14 | The Firestone Tire & Rubber Company | Polyurethane elastomers having prolonged flex life and tires made therefrom |
| US4182825A (en) * | 1978-10-11 | 1980-01-08 | Thiokol Corporation | Polyether based urethanes with superior dynamic properties |
| US4786703A (en) * | 1987-04-15 | 1988-11-22 | Air Products And Chemicals, Inc. | Process for the preparation of polyisocyanate prepolymers and polyurethanes having high temperature performance and low hysteresis |
| US4934425A (en) * | 1988-03-23 | 1990-06-19 | Uniroyal Chemical Company, Inc. | Non-pneumatic tire |
| US5223599A (en) * | 1992-04-10 | 1993-06-29 | Uniroyal Chemical Company, Inc. | Polyurethane elastomer and non-pneumatic tire fabricated therefrom |
-
1995
- 1995-11-17 US US08/561,650 patent/US5654390A/en not_active Expired - Fee Related
-
1996
- 1996-11-01 WO PCT/US1996/016961 patent/WO1997019123A1/en active IP Right Grant
- 1996-11-01 AU AU75188/96A patent/AU7518896A/en not_active Abandoned
- 1996-11-01 DE DE69620005T patent/DE69620005T2/en not_active Expired - Fee Related
- 1996-11-01 JP JP09519719A patent/JP3073023B2/en not_active Expired - Fee Related
- 1996-11-01 EP EP96937714A patent/EP0861276B1/en not_active Expired - Lifetime
- 1996-11-01 CA CA002235592A patent/CA2235592A1/en not_active Abandoned
- 1996-11-04 TW TW085113453A patent/TW381103B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AU7518896A (en) | 1997-06-11 |
| EP0861276B1 (en) | 2002-03-20 |
| JPH11500179A (en) | 1999-01-06 |
| TW381103B (en) | 2000-02-01 |
| US5654390A (en) | 1997-08-05 |
| JP3073023B2 (en) | 2000-08-07 |
| WO1997019123A1 (en) | 1997-05-29 |
| EP0861276A1 (en) | 1998-09-02 |
| DE69620005T2 (en) | 2002-09-19 |
| DE69620005D1 (en) | 2002-04-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |