Patent ID: 6688872
Filing Date: 2004-02-10
Classification: B29C,B29K

Abstract:
An apparatus for making an unvulcanized rubber tape having a finished thickness TO in a range of from 0.3 to 1.5 mm, comprisingan extruder comprising a passage for unvulcanized rubber defining an outlet for the extruded unvulcanized rubber, and a pair of calendar rollers disposed near said outlet for adjusting the thickness of the extruded unvulcanized rubber passing therebetween, said passage comprised of a transforming part having an inlet for the unvulcanized rubber at its upstream-side end, and a thinning part on the downstream side thereof defining said outlet at its downstream-side end, said transforming part gradually changing in the cross sectional shape from a circle to a flat shape in the lower course of the passage, said thinning part having a flat cross sectional shape and gradually decreasing in thickness in the lower course of the passage, said thickness TO and a width WO of the unvulcanized rubber tape, a width W1 of said inlet, a width WA and a thickness TA of said outlet, a length L of the transforming part, a width W2 of the transforming part at its downstream-side end, and a pressure P of the unvulcanized rubber flowing into said inlet satisfy the following relationships 0.7Ã—W0&lE;WA&lE;1.0Ã—W01.5Ã—TO&lE;TA&lE;10Ã—T0WA21+0.2Ã—L P>40 kgf/sq.cm.