Process for the manufacture of polymer solutions
First Claim
1. A process for the manufacture of a solution of high molecular essentially linear polyurethane elastomer which comprises reacting together, in a first portion of a liquid which is a solvent for the polyurethane, an organic diisocyanate, an essentially linear hydroxyl-terminated polyester, polyesteramide or polyether and a low molecular weight difunctional isocyanate-reactive compound the amount of said liquid in said first portion being less than sufficient for a solution in that amount of solvent of all of the polyurethane to be formed from the initial reactants to have a viscosity which does not exceed the viscosity desired for the final product, initially carrying out the reaction in said first portion of solvent until formation of polyurethane increases the viscosity to substantially the value desired for the final product and thereafter continuing the reaction while adding the remaining solvent for the polyurethane in a continuous manner and at such a rate that the viscosity of the solution remains substantially constant at the value desired for the final product, whereby the viscosity-reducing effect of the solvent addition counteracts the viscosity-increasing effect of the continuing reaction, and finally terminating the reaction when the desired concentration of polyurethane in the solution has been achieved.
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Abstract
A process for manufacture of solutions of polymers of high molecular weight by carrying out a reaction in solution leading to formation of the polymer, wherein the reaction is carried out initially in the presence of only a portion of the total solvent to be used, until the viscosity of the solution approaches or exceeds the value finally desired, and thereafter the remainder of the solvent is added whilst reaction is still proceeding.
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Citations
1 Claim
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1. A process for the manufacture of a solution of high molecular essentially linear polyurethane elastomer which comprises reacting together, in a first portion of a liquid which is a solvent for the polyurethane, an organic diisocyanate, an essentially linear hydroxyl-terminated polyester, polyesteramide or polyether and a low molecular weight difunctional isocyanate-reactive compound the amount of said liquid in said first portion being less than sufficient for a solution in that amount of solvent of all of the polyurethane to be formed from the initial reactants to have a viscosity which does not exceed the viscosity desired for the final product, initially carrying out the reaction in said first portion of solvent until formation of polyurethane increases the viscosity to substantially the value desired for the final product and thereafter continuing the reaction while adding the remaining solvent for the polyurethane in a continuous manner and at such a rate that the viscosity of the solution remains substantially constant at the value desired for the final product, whereby the viscosity-reducing effect of the solvent addition counteracts the viscosity-increasing effect of the continuing reaction, and finally terminating the reaction when the desired concentration of polyurethane in the solution has been achieved.
Specification
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- Resources
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Current AssigneeImperial Chemical Industries Limited (Nouryon BV)
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Original AssigneeImperial Chemical Industries Limited (Nouryon BV)
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InventorsBrown, James Peter, Aitken, Roxburgh Richmond
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Primary Examiner(s)Lieberman, Allan
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Application NumberUS05/170,053Time in Patent Office1,701 DaysField of Search260/34.2, 260/77.5 A, 260/77.5 SP, 260/31.2 N, 260/32.6 UA, 260/77.5 AA, 260/75 NKUS Class Current523/305CPC Class CodesC08G 18/0852 the solvents being organicC08G 18/10 Prepolymer processes involv...C08G 18/302 WaterC08G 18/32 Polyhydroxy compounds; Poly...C08G 18/606 Polyester-amidesC08G 18/6505 the low-molecular compounds...C09J 175/04 Polyurethanes
