Process of making a high melt viscosity block co-polyester
AssigneeGeneral Electric Company
InventorsWillem Frederik Hendrik Borman, Donald Irving Craft, Mortor Kramer
Life of this patent
Estimating the term…
Abstract
A novel process is disclosed for preparing a high melt viscosity block co-polyester of at least two different linear polyesters. The process comprises melt blending the polyesters and, thereafter, subjecting the melt blended polyesters to a temperature of 10.degree.-50.degree. C. below the melting point of the lowest melting ingredient in the blend until the melt viscosity has increased to at least 10,000 poises at a temperature 10.degree.-15.degree. C. above the melting point of the blend.
Claims12
A method of preparing a high melt viscosity thermoplastic polyester blend of at least two different polyesters having repeating units of the formula:
- ##STR2## wherein n and m are positive integers between 1 and 10;
- said method consisting essentially of melt blending at least two low to medium melt viscosity linear polyesters, wherein at least one of the low to medium viscosity linear polyesters is a branched co-polyester that includes from 0.01 to 5 mole percent based on the terephthalate units, of units of branching component which contains at least three ester-forming groups, and thereafter subjecting the melt blended polyesters to a temperature of 10.degree.-50.degree. C. below the melting point of the lowest melting ingredient in the blend until the melt viscosity has increased to at least 10,000 poises at a temperature of 10.degree.-15.degree. C. above the melting point of the blend.
A method of preparing a high melt viscosity thermoplastic blend of polyethylene terephthalate and polybutylene terephthalate, said method comprising melt blending a low to medium melt viscosity polybutylene terephthalate with a low to medium melt viscosity polyethylene terephthalate and thereafter subjecting the melt blended polyesters to a temperature of 10.degree.-50.degree. C. below the melting point of the lowest melting polyester in the blend until the melt viscosity has increased to a viscosity of 25,000-75,000 poises at a temperature 10.degree.-15.degree. C. above the melting point of the blend.
Dependencies are inferred from the claim text.