Peelable seal and method of making and using same

摘要

A peelable seal comprises a mixture of at least two immiscible polymers. The first polymer forms a continuous phase in the peelable seal, whereas the second polymer is dispersed in the continuous phase. For example, a peelable seal can also be made from a mixture of an ethylene polymer with a melt index in the range from about 0.1 to about 20 g/10 minutes and a propylene polymer with a melt flow rate in the range from about 0.01 to about 2 g/10 minutes. The two polymers define a shear viscosity differential: DELTA=|(eta1-eta2)/eta1|, wherein eta1 and eta2 are the respective shear viscosity for the first and second polymers at a temperature of 230° C. and a shear rate of about 100 radian/second. Preferably, the shear viscosity differential is less than about 100%.