Coat hanger die
AssigneeToa Nenryo Kogyo Kabushiki Kaisha
InventorYutaka Matsubara
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Abstract
An improved coat hanger die is provided wherein the manifold is curved and wherein the manifold radius, coat hanger slit part thickness and the form of the coat hanger die are determined by a formula which is disclosed all in relation to the radius of the manifold at its inlet. The radius of the manifold at its inlet is selected in consideration of the flow characteristics of the resin melt to provide a low melt velocity at the inlet.
Claims7
A coat hanger die comprising a coat hanger slit part, manifold part and manifold inlet part, wherein the manifold part is in the form of a coat hanger wherein the depth of the coat hanger slit part is defined by the following formula (2):
- ##EQU3## in which Ro is the radius of a circle equivalent to the cross section of the manifold on the center line of the die, n is the flow behavior index of the melt resin, m is the ratio of the residence time of a resin flowing through the manifold and die side end to the residence time of a resin flowing through the coat hanger slit part along the center line of the die and ranges from 1 to 50, L is the required half width of the die, and wherein the customary assumptions regarding resin melt viscosity, melt flow through the die, melt temperature and residence time have been made.
Dependencies are inferred from the claim text.