摘要:
A method of curtain coating that applies a free falling curtain of liquid coating composition onto a running support is disclosed. In the method, the sides of the support parallel to the running direction of the support are bent downwardly before the curtain is applied, and thus are not coated, and are subsequently unbent.
摘要:
A device for coating a travelling web of material such as photographic paper with a coating liquid includes a means for transporting the web along a path of travel and a coating hopper of the slot or slide type positioned above the path of travel and provided with a pouring lip from which the coating liquid falls freely as a liquid curtain onto the web to be coated. The pouring lip is provided with a rectilinear sharp edge at a distance of 0.7 to 2.5 mm from an imaginary vertical plane in the operative position of the hopper which is at a tangent to the pouring lip at that boundary surface which is on the coating liquid side. By virtue of this sharp edge a straight wetting line, and consequently a very even curtain thickness can be obtained. If the coating hopper is of the slide type whose slide surface is cylindrically curved in the area near the pouring lip the radius of curvature is preferably within the range between 20 and 40 mm, particularly between 25 and 35 mm. The minimum flow rate necessary for maintaining a stable liquid curtain is thereby considerably decreased.
摘要:
A separate or incorporated no drip suck back unit for use with a liquid applying apparatus, wherein materials moving relative to the apparatus are selectively spotted, beaded or coated with a liquid, such as glue or plastic, through one or more nozzles, and wherein the no drip suck back unit prevents excess liquid from flowing or dripping from the apparatus during periods when no liquid is being applied. The unit consists of a housing with two interior passageways, one for liquid and the other for air, separated by a flexible diaphragm. The liquid being applied flows through the liquid passageway on its way to the nozzle. During application, compressed air is introduced into the air passageway, thus flexing the diaphragm away from its median position and reducing the volume of the liquid passageway. When application is stopped, the air passageway is vented to the atmosphere, thus reducing the pressure therein and permitting a spring to return the diaphragm to its median position. This return motion of the diaphragm increases the volume of the liquid passageway and draws the liquid back away from the nozzle so that no drip occurs.
摘要:
Extrusion coating with high line speeds of up to 600 mpm may be achieved without sacrificing the adhesion of the coating to the substrate by using an ethylene copolymer with up to 3% by weight copolymer, preferably 0.5 to 2.5% by weight VA, as the coating polymer. The extrusion temperature is in the region of incipient degradation, but maintained below the level which gives undesired degradation leading to odor or discoloration.
摘要:
A cascade coater having a slideway and extending therein a slot which widens in the downstream direction as it meets the associated slideway. The slot is formed by upstream and downstream boundary walls, the downstream wall joining with a flat face angled with respect to that wall and the surface of the slideway or being curved to meet the slideway. The upstream and downstream surfaces of the slideway can lie in the same plane or different planes which are parallel and spaced apart by a distance of about 1 mm.
摘要:
Apparatus is provided for the simultaneous application of a plurality of layers of liquid coating compounds to an article. The apparatus and method of use thereof is, in one aspect, intended for coating a film with photographic emulsions.