Eastman-kodak Company

Christopher L Bower

Andrew Clarke

Kim E Goppert

Christopher B Rider

An indicator device includes a surface provided with at least one channel or at least one through-hole with at least two openings, wherein flowable material in an immobile state is provided adjacent to the channel or adjacent to a first opening of the through-hole, such that after application of a stimulus the material is directed along the channel by the action of capillary forces or into the at least one through-hole by the action of capillary forces and emerges at a second opening, thereby providing an indication of the application of the stimulus.

Indicators

The invention provides a method of creating a material for use as a material to be coated by curtain coating, comprising the step of: creating a surface texture of said material such that when said material is coated with a freely falling curtain formed of a composite layer of one or more coating compositions that impinges at a point of impingement against a continuously moving receiving surface of said material using roughness assisted wetting, the height of the composite layer at a distance &lgr; from the point of impingement, in which &lgr; is the average periodicity of the surface texture, is less than or equal to R . The invention also provides a method of identifying a material suitable for coating with Roughness Assisted coating.

Method of creating and coating a material

An apparatus and method of bead coating a web using a coating die. The method comprises forming one or more layers of coating material using the coating die and allowing the one or more layers to impinge on the web as the web and die move relative to each other. The web surface has an average peak to peak roughness as defined by DIN 4768, ISO4287 or BS1134 between 2 &mgr;m and 20 &mgr;m. The layer of coating material forming a wetting layer adjacent to the web has a viscosity of between 35 mPas and 200 mPas measured at a shear rate of substantially 10,000 s . An electrostatic field is provided at the point at which the layers impinge on the web to stabilize the layers of coating material. The method enables the web being coated to be conveyed at a speed greater than 400 cm/s relative to the coating die whilst avoiding the problem of air entrainment.

Apparatus and method of coating a web

A method of curtain coating, the curtain being formed from at least one layer of coating solution having a composite density &rgr; (kgm ) and a total volumetric flow rate per unit curtain width Q (m s ), the curtain being allowed to free fall a distance h (m), at a velocity U (ms ), onto a continuously moving substrate having a velocity S (ms ) with an application angle of &thgr; between the horizontal and tangent to the substrate at the point of impingement, the dynamic surface tension at the rear of the falling curtain being &sgr; (mNm ), the aforementioned variable parameters being controlled so as to prevent recirculation.

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Headington, United Kingdom

Christopher L Bower