Tdk Corporation

Eiichi Watanabe

Kazuo Katai

Eizo Tsunoda

Yutaka Shimizu

Naomi Yoshiike

Katsumi Onozawa

An extrusion coating head which is disposed between a drier for performing a non-contact drying operation and a support roll located at the upstream side of and nearest to the drier is designed so that a back edge surface thereof is designed to have an round surface having a radius of curvature R which satisfies the following inequality: 3 mm.ltoreq.R.ltoreq.30 mm, and the entire R-surface portion of the back edge of the coating head is located at a position higher than a tangential line drawn to the front edge surface at a slit-side edge point of the front edge so as to project toward the web side. The running web is coated with the coating liquid by the extrusion-type coating head, and then dried through a non-contact drying process.

Extrusion coating method and coating apparatus for coating both sides of

In a coating method of extruding a coating liquid through a slit of an extrusion-type coating head to coat a running web, at a starting or restarting of the coating, the coating liquid is extruded through the slit of the coating head while the coating head is away from the web, and then the coating is started while a slightly large clearance is kept between the coating head and the web at the upstream side of the coating head, thereafter changing the coating state or arrangement to a steady coating state. Therefore, occurrence of a thicker portion of the coating film on the web at the start of the coating can be prevented. Further, at the end or interruption of the coating, the coating state or arrangement of the coating head is changed from the steady coating state to a state wherein a slightly large clearance is kept between the coating head and the web at the upstream side, and the coating head is moved away from the web to end the coating. Therefore, occurrence of a thicker portion of the coating film on the web at the end of the coating can be prevented. With this arrangement, at the start, restart, end and interruption of the coating, a uniformly coated film can be also formed on one surface of the web whose other surface has already been coated with a coating liquid.

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Saku, Japan

Eiichi Watanabe