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...
Patent
1993-12-30
1995-02-21
Welsh, Maurice J.
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...
528 65, C08G 1810
Patent
active
053916824
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a thermoplastic polyurethane elastomer, a process for producing same, an apparatus for producing same, and elastomer fibers made from same. More specifically, this invention relates to a polyurethane elastomer having a high molecular weight and a narrow molecular-weight distribution and containing a very small amount of polyurethane substrate-based small grains, a process for producing same, an apparatus for producing same and elastomer fibers made from same.
BACKGROUND TECHNIQUE
As a method for producing thermoplastic polyurethane, a solution polymerization method using a solvent and a bulk melt polymerization method not using a solvent have been known.
A method for producing a polyurethane elastomer by solution-polymerizing a polymer glycol, a diisocyanate compound and a crosslinking agent batchwise in a solvent gives a polyurethane elastomer having a relatively narrow molecular-weight distribution, but does not provide so high a degree of polymerization, requires a step of separating the solvent from the reaction product after the reaction, and is batchwise. Therefore, said method is extremely inefficient.
Japanese Patent Publication Sho 39-17098 (No. 17,093/1964) discloses a method for producing a polyurethane elastomer by bulk-polymerizing a polymer glycol and a diisocyanate compound batchwise in the absence of a solvent with a kneading machine such as a kneader.
This method affords a polyurethane elastomer having a high degree of polymerization. However, this polyurethane elastomer has a wide molecular-weight distribution and shows strong adhesion, so that said elastomer can hardly be peeled off from a rotating blade. In general, when conducting the reaction batchwise, it is very hard to strictly regulate proportions of starting materials to be fed in each batch, treatment temperatures, treatment times, a water content, extrusion times or the like. Due to this, a degree of polymerization and a molecular-weight distribution cannot be controlled and hence, it is quite difficult to make products uniform.
On the other hand, Japanese Patent Publication Sho 44-25600 (No. 25,600/1969) discloses a method for continuously producing a thermoplastic polyurethane resin, which comprises kneading a heat-molten liquid polyisocyanate compound and a compound containing at least two groups having an active hydrogen capable of reacting with an isocyanate group in a multi-screw extruder for a residence time of 3 to 60 minutes to polymerize them. This document describes 50.degree. to 200.degree. C. as a polymerization temperature, and employs a residence time of 7 to 15 minutes and a polymerization temperature (a cylinder temperature) of 140.degree. to 195.degree. C. in Examples.
Japanese Patent Publication Sho 49-3451 (No. 3,451/1974) discloses a method for producing polyurethane elastic yarns by a continuous synthesis in the absence of a solvent and a direct spinning, which method includes a step of preliminarily reacting a high-molecular dihydroxy compound having a molecular weight of 500 or more with an organic diisocyanate such that 70 to 100% of a finally necessary amount of the high-molecular dihydroxy compound substantially becomes an isocyanate group, Said document shows 150.degree. to 250.degree. C. as a reaction temperature of a prepolymer formed in the above preliminary reaction step, the remaining high-molecular dihydroxy compound and a low-molecular dihydroxy compound, and adopts 180.degree. C..times.15 minutes and 160.degree. C..times.20 minutes as reaction conditions in Examples.
Japanese Patent Publication Hei 3-54963 (No. 54,963/1991) discloses a method in which when continuously producing a thermoplastic polyurethane by reacting in an extruder a high-molecular diol having an average molecular weight of 500 to 3,000, a low-molecular diol having a molecular weight of less than 500 and an organic diisocyanate, a molar ratio of the amount of isocyanate groups of the organic diisocyanate to a total amount of hydroxyl groups of the high-molecular diol and the low
REFERENCES:
patent: 3963679 (1976-06-01), Ullrich et al.
patent: 4192928 (1980-03-01), Tanaka et al.
Kitano Takahiro
Ogawa Yasuhiro
Sagawa Kenzo
Yamada Tadaaki
Yamashita Michiya
Kanebo Ltd.
Welsh Maurice J.
LandOfFree
Thermoplastic polyurethane elastomer, process for producing same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoplastic polyurethane elastomer, process for producing same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic polyurethane elastomer, process for producing same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1930998