Coating method using an extrusion type coating apparatus

An extrusion type coating apparatus for applying a coating fluid to a continuously running flexible support comprising:

• a back edge portion having a back edge surface;
• a doctor edge portion having a doctor edge surface, said doctor edge portion being disposed downstream of said back edge portion in the direction of running of said support;
• a slot formed between said back edge surface and said doctor edge surface for applying said coating fluid onto a surface of said flexible support, said flexible support running continuously over both said back edge surface and said doctor edge surface;
• said doctor edge surface being a single inclined curved surface having a single curvature,
• wherein said doctor edge surface does not intersect a plane extending between a downstream end of said doctor edge surface and a slot-top portion of said back edge surface, and
• wherein an angle .theta..sub.1 between a tangent to said back edge surface and said plane, and an angle .theta..sub.2 between said plane and said support stretched downstream from said downstream end of said doctor edge surface, satisfy the conditions:
• 150.degree.<.theta..sub.1 <180.degree.
• and
• 150.degree.<.theta..sub.2 <180.degree..
• wherein the range of thickness of said coating fluid applied to said support is adjusted by changing said angle .theta..sub.2.

A method of applying a coating fluid to a continuously running flexible support using an extrusion type coating apparatus comprising the steps of:

• running said flexible support continuously over both a back edge portion and a doctor edge portion disposed downstream of said back edge portion in the direction of running of said support;
• applying said coating fluid onto a surface of said flexible support through a slot formed between said back edge portion and said doctor edge portion;
• forming a doctor edge surface of said doctor edge portion as a planar surface so that said doctor edge surface does not intersect a plane extending between a downstream end of said doctor edge surface and a slot-top portion of a back edge surface of said back edge portion.
• wherein said doctor edge portion and said back edge portion are formed so that an angle .theta..sub.1 between a tangent to said back edge surface and said plane, and an angle .theta..sub.2 between said plane and said support stretched downstream from said downstream end of said doctor edge surface, satisfy the conditions:
• 150.degree.<.theta..sub.1 <180.degree.
• and
• 150.degree.<.theta..sub.2 <180.degree.,
• and
• adjusting the range of thickness of said coating fluid applied to said support is by changing an angle .theta..sub.2.

A method of applying a coating fluid to a continuously running flexible support using an extrusion type coating apparatus comprising the steps of:

• running said flexible support continuously over both a back, edge portion and a doctor edge portion disposed downstream of said back edge portion in the direction of running of said support;
• applying said coating fluid onto a surface of said flexible support through a slot formed between said back edge portion and said doctor edge portion;
• forming a doctor edge surface of said doctor edge portion as a curved surface having a single curvature so that said doctor edge surface does not intersect a plane extending between a downstream end of said doctor edge surface and a slot-top portion of a back edge surface of said back edge portion,
• wherein said doctor edge portion and said back edge portion are formed so that an angle .theta..sub.1 between a tangent to said back edge surface and said plane, and an angle .theta..sub.2 between said plane and said support stretched downstream from said downstream end of said doctor edge surface, satisfy the conditions:
• 150.degree.<.theta..sub.1 <180.degree.
• and
• 15.degree.<.theta..sub. <
• 18.degree. .
• adjusting the range of thickness of said coating fluid applied to said support is by changing an angle .theta..sub.2.