Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
2000-01-17
2001-07-03
Cooney, Jr., John M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C521S155000, C521S159000, C521S170000, C521S174000, C528S076000, C528S077000, C528S085000
Reexamination Certificate
active
06255431
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to blends of poly-tetramethylene polyether glycols and polyoxyalkylene polyether polyols having a low degree of unsaturation of 0.04 or less, and to the cast elastomers, spandex fibers, and thermoplastic polyurethanes made therefrom.
BACKGROUND OF THE INVENTION
Polyurethane elastomers often utilize one or more polytetramethylene ether glycols (PTMEG's) as a polyol component to react with one or more polyisocyanates such as MDI because they can impart to the elastomer the high level of mechanical properties required for specific applications. PTMEG's are often used for such applications where high tensile strength, low compression set, high resilience, and/or a high modulus of elasticity are required. PTMEG's, however, can be difficult and expensive to make due to the availability of starting materials and the formation of undesired side-reaction products during synthesis.
It would therefore be desirable to provide polyol compositions that can be used to manufacture high-quality polyurethane elastomers while reducing the amount of PTMEG required.
SUMMARY OF THE INVENTION
Thus, there is provided according to the present invention polyol compositions comprising
(A) a polytetramethylene ether glycol, and
(B) a trifunctional active hydrogen compound-initiated polyoxyalkylene polyether polyol having a degree of unsaturation of not greater than 0.04 milliequivalents per gram of said polyether polyol.
The polyol compositions according to the present invention can be used for the manufacture of polyurethane elastomers via a one-shot technique or a prepolymer technique. Elastomers based on the polyol compositions of the invention exhibit a good combination of properties such as tensile strength, compression set, resilience, and/or a modulus of elasticity, which often previously required the use pure PTMEG. Other properties, such as elongation and resilience, can often be improved by utilizing the blend compositions of the invention.
Thus, in one embodiment of the invention, there is provided a prepolymer obtained by reacting a polyol composition comprising at least the above-described PTMEG and a polyoxyalkylene polyether polyol having a degree of unsaturation of 0.04 or less, with an organic polyisocyanate. The prepolymer may be isocyanate terminated by adding a sub-stoichiometric amount of the polyol composition to the isocyanate, or hydroxyl terminated by adding to the isocyanate a molar excess of the polyol composition.
In another embodiment of the invention, there is provided an elastomer made by reacting an organic di- or polyisocyanate with the polyol composition, optionally in the presence of a hydroxyl and/or amine functional chain extender at a an equivalent NCO:OH ratio of at least 1.5:1, where the polyol composition is made up of at least PTMEG and a polyoxyalkylene polyether polyol having a degree of unsaturation of 0.04 or less. The polyol composition of the invention may be a principal polyol component of the urethane elastomer-forming reaction mixture (i.e., one-shot method) or it may first be incorporated into a prepolymer prior to incorporation into the urethane elastomer-forming reaction (i.e., prepolymer methods).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
PTMEG's useful in the practice of the invention generally have a number average molecular weight ranging from 500 to 5000, preferably 800 to 3000, more preferably from 1000 to 2600. Techniques for the manufacture of PTMEG are well-known in the art, such as described in U.S. Pat. No. 3,393,243, the disclosure of which is incorporated herein by reference Examples of useful PTMEG's include POLYTHF® 650, POLYTHF® 1000, POLYTHF® 2000, and POLYTHF® 2900.
PTMEG's are generally synthesized by a ring-opening chain extension reaction of the monomeric tetrahydrofuran (THF). In one well-known method, the ring-opening reaction is catalyzed by fluorosulfonic acid, followed by hydrolysis of sulfate ester groups and water extraction of the acid, followed by neutralization and drying. In many cases, the PTMEG will be solid at room temperature because of its high degree of crystallinity. In the event one desires to employ a room temperature liquid PTMEG, the THF can be copolymerized with alkylene oxides (also known as cyclic ethers or monoepoxides) as suggested in U.S. Pat. No. 4,211,854, incorporated herein by reference. Such copolymers have an A-B-A block-heteric structure, wherein the A blocks are random copolymers of tetrahydrofuran and alkylene oxides, and the B block is made up of polytetramethylene oxides.
The cyclic ethers copolymerizable with tetrahydrofuran are not particularly limited, provided that they are cyclic ethers capable of ring-opening polymerization, and may include, for example, 3-membered cyclic ethers, 4-membered cyclic ethers, cyclic ethers such as tetrahydrofuran derivatives, and cyclic ethers such as 1,3-dioxolan, trioxane, etc. Examples of cyclic ethers include ethylene oxide, 1,2-butene oxide, 1,2-hexene oxide, 1,2-tert-butyl ethylene oxide, cyclohexene oxide, 1,2-octene oxide, cyclohexylethylene oxide, styrene oxide, phenyl glycidyl ether, allyl glycidyl ether, 1,2-decene oxide, 1,2-octadecene oxide, epichlorohydrin, epibromohydrin, epiiodohydrin, perfluoropropylene oxide, cyclopentene oxide, 1,2-pentene oxide, propylene oxide, isobutylene oxide, trimethyleneethylene oxide, tetramethyleneethylene oxide, styrene oxide, 1,1-diphenylethylene oxide, epifluorohydrin, epichlorohydrin, epibromohydrin, epiiodohydrin, 1,1,1-trifluoro-2-propylene oxide, 1,1,1-trifluoro-2-methyl-2-propylene oxide, 1,1,1-trichloro-2-methyl-3-bromo-2-propylene oxide, 1,1,1-tribromo-2-butyleneoxide, 1,1,1-trifluoro-2-butyleneoxide, 1,1,1-trichloro-2-butylene oxide, oxetane, 3-methyloxetane, 3,3-dimethyloxetane, 3,3-diethyloxetane, 3,3-bis(chloromethyl)oxetane, 3,3,-bis(bromomethyl)oxetane, 3,3-bis(bromomethyl)oxetane, 3,3-bis(fluoromethyl)oxetane, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-methyl-3-chloromethyltetrahydrofuran, 3-ethyltetrahydrofuran, 3-isopropyltetrahydrofuran, 2-isobutyltetrahydrofuran, 7-oxabicyclo(2,2,1)heptane, and the like.
The content of the copolymerized cyclic ether, if present, in a PTMEG may be within the range of from 5 to 95% by weight, but when obtaining a copolymerized polyetherglycol containing oxytetramethylene groups as a main component which is effective as the soft segment in a polyurethane elastomer such as spandex, the amount of the cyclic ether in the A block copolymerizable with THF is generally from 30 to 70 wt %. In the event one chooses to randomly copolymerize cyclic ethers with THF across the whole copolymer, the amount of cyclic ether may range from 5 to 60 weight % of the copolymer.
Additionally, in the synthesizing reaction of PTMEG, a part of the starting THF may be replaced with an oligomer of PTMEG as the starting material. Further, in the synthesizing reaction of a copolymerized polyetherglycol, an oligomer of PTMEG or an oligomer of the polyetherglycol to be synthesized may also be added as a part of the starting material to carry out the reaction. In such a case, the oligomer generally has a molecular weight lower than the polymer to be synthesized. More specifically, one may use an oligomer having a number-average molecular weight within the range of from 100 to 800 when synthesizing a polymer with a number-average molecular weight of 1000 or more, and an oligomer with a number-average molecular weight of 100 to 2000 when synthesizing a polymer with a number-average molecular weight of 3000 or more. Also, an oligomer separated by fractional extraction or vacuum distillation from the PTMEG or the copolymerized polyetherglycol synthesized may be employed. Such an oligomer may be added in an amount of up to 10% by weight into the starting monomer.
The degree of polymerization tends to decrease as the reaction temperature is increased and therefore, and also in view of the polymerization yield, the polymerization temperature should preferably be −10° to 120° C., more preferably 30° to 80° C. If
Fishback Thomas L.
Heyman Duane A.
Jaglowski Adam J.
Reichel Curtis J.
BASF Corporation
Borrego Fernando A.
Cooney Jr. John M.
LandOfFree
Compositions of polytetramethylene ether glycols and polyoxy... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compositions of polytetramethylene ether glycols and polyoxy..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compositions of polytetramethylene ether glycols and polyoxy... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534693