Abstract: A liquid coating is formed on a substrate by electrostatically spraying drops of the liquid onto a liquid-wetted conductive transfer surface and transferring a portion of the thus-applied liquid from the transfer surface to the substrate. Optionally, one or more nip rolls force the substrate against the transfer surface, thereby decreasing the time required for the drops to spread and coalesce into the coating. Preferably, the coating is passed through an improvement station comprising two or more pick-and-place devices that improve the uniformity of the coating. The coating can be transferred from the conductive transfer surface to a second transfer surface and thence to the substrate. Insulative substrates such as plastic films can be coated without requiring substrate pre-charging or post-coating neutralization. Porous substrates such as woven and nonwoven webs can be coated without substantial penetration of the coating into or through the substrate pores.

Abstract: The uniformity of a wet coating on a substrate is improved by contacting the coating at a first position with the wetted surfaces of periodic pick-and-place devices, and re-contacting the coating with such wetted surfaces at positions on the substrate that are different from the first position and not periodically related to one another with respect to their distance from the first position. A coating is applied to a substrate by applying an uneven wet coating, contacting the coating at a first position with the wetted surfaces of periodic pick-and-place devices, and re-contacting the coating with such wetted surfaces at positions on the substrate that are different from the first position and not periodically related to one another with respect to their distance from the first position. These methods can provide extremely uniform coatings and extremely thin coatings, at very high rates of speed. The coatings can be applied in lanes with sharply defined edges and independently adjustable coating calipers.

Abstract: Continuous void-free uniform coatings are formed on filamentous articles by applying a voided or otherwise substantially uneven coating to at least some of the exposed portion of a filamentous article or to a rotating substrate. The filamentous article or substrate is passed through an improvement station containing a plurality of coating-wetted rolls that contact and re-contact the wet coating at different positions along the length of the filamentous article or rotating substrate, wherein the periods of the rolls improve the uniformity of the coating. For coatings applied to a rotating substrate, the uniform wet coating is transferred to the filamentous article. The final coating can be very thin, very uniform and completely or substantially void-free. The coating improvement can be quickly and easily obtained using low cost equipment.

Abstract: A liquid coating is formed by spraying drops of liquid onto a substrate or a transfer surface from an electrostatic spray head that produces a mist of drops and a wet coating in response to an electrostatic field. During spraying, the electrostatic field is repeatedly altered to change the pattern deposited by the drops. The wet coating can be contacted with two or more pick-and-place devices that improve the uniformity of the coating.

Abstract: Continuous void-free uniform coatings are formed on substrates of limited length. The substrate is wrapped around a mounting roll and nipped between the mounting roll and one or more pick-and-place contacting rolls. Coating liquid is applied to the substrate or to a pick-and-place roll, preferably as a pattern of stripes. The mounting roll, substrate and pick-and-place rolls are caused to rotate for a plurality of revolutions. Wetted surface portions of the pick-and-place roll repeatedly contact the substrate, the coating is repeatedly picked up from and placed onto the substrate, and the coating becomes more uniform. Extremely uniform and extremely thin coatings can be quickly and easily obtained, with easy adjustment of the final coating thickness.

Abstract: A liquid coating is formed on a substrate by electrostatically spraying drops of the liquid onto a liquid-wetted conductive transfer surface and transferring a portion of the thus-applied liquid from the transfer surface to the substrate. Optionally, one or more nip rolls force the substrate against the transfer surface, thereby decreasing the time required for the drops to spread and coalesce into the coating. Preferably, the coating is passed through an improvement station comprising two or more pick-and-place devices that improve the uniformity of the coating. The coating can be transferred from the conductive transfer surface to a second transfer surface and thence to the substrate. Insulative substrates such as plastic films can be coated without requiring substrate pre-charging or post-coating neutralization. Porous substrates such as woven and nonwoven webs can be coated without substantial penetration of the coating into or through the substrate pores.

Abstract: A liquid coating is formed by spraying drops of liquid onto a substrate or a transfer surface from an electrostatic spray head that produces a mist of drops and a wet coating in response to an electrostatic field. During spraying, the electrostatic field is repeatedly altered to change the pattern deposited by the drops. The wet coating can be contacted with two or more pick-and-place devices that improve the uniformity of the coating.

Abstract: The uniformity of a wet coating on a substrate is improved by contacting the coating at a first position with the wetted surfaces of periodic pick-and-place devices, and re-contacting the coating with such wetted surfaces at positions on the substrate that are different from the first position and not periodically related to one another with respect to their distance from the first position. A coating is applied to a substrate by applying an uneven wet coating, contacting the coating at a first position with the wetted surfaces of periodic pick-and-place devices, and re-contacting the coating with such wetted surfaces at positions on the substrate that are different from the first position and not periodically related to one another with respect to their distance from the first position. These methods can provide extremely uniform coatings and extremely thin coatings, at very high rates of speed. The coatings can be applied in lanes with sharply defined edges and independently adjustable coating calipers.

Abstract: Continuous void-free uniform coatings are formed on substrates by repeatedly contacting the substrate at a first position with wetted surface portions of at least two rotating wire-wound coating rods and re-contacting the substrate with such wetted surface portions at a different position or positions on the substrate. The coating is repeatedly picked up from and placed onto the substrate and made more uniform. Extremely uniform and extremely thin coatings can be quickly and easily obtained using low cost equipment.

Abstract: A sufficient number of pick-and-place devices (e.g., rolls) whose periods of contact with a substrate are equal or substantially equal to one another are used to form continuous void-free uniform coatings despite the occurrence of unintended or intended coating caliper surges, depressions or voids. The wetted surfaces of the devices contact and re-contact the coating at positions on the substrate that are different from one another. Extremely uniform and extremely thin coatings can be obtained at very high rates of speed. The pick-and-place devices also facilitate drying and reduce the sensitivity of drying ovens to coating caliper surges. Equipment containing the pick-and-place devices is simple to construct, set up and operate, and can easily be adjusted to alter coating thickness and compensate for coating caliper variations.

Abstract: A method of making abrasive particles having a specified shape and abrasive articles containing abrasive particles having a specified shape.

Abstract: A system for coating a substrate with ultra-thin layers in stripes includes moving the substrate through a coating station and forming a composite layer including coating fluids and a carrier fluid. The composite layer flows at a rate that is sufficiently high to form a continuous flowing fluid bridge of composite layer to the substrate surface and to contact the substrate with the flowing composite layer to interpose the coating layers between the substrate and the carrier fluid. The carrier fluid is removed while leaving the coating fluid deposited on the substrate as a coating layer.

Abstract: A system for coating a substrate with an ultra-thin layer includes moving the substrate through a coating station and forming a composite layer including a coming fluid and a carrier fluid. The composite layer flows at a rate that is sufficiently high to form a continuous flowing fluid bridge of composite layer to the substrate surface and to contact the substrate with the flowing composite layer to interpose the coating layer between the substrate and the carrier fluid. The carrier fluid is removed while leaving the coating fluid deposited on the substrate as a coating layer.

Abstract: A unified, composite tape structure comprising two outer pressure-sensitive adhesive layers and a backing joined via melt processing. At least one of the backing and two outer adhesive layers is not mutually coextensive. A method of making the tape comprising the use of melt processing is also disclosed.

Abstract: A method utilizing melt processing for making a unified, composite tape structure that includes two outer pressure-sensitive adhesive layers and a backing wherein at least one of the two outer adhesive layers is not mutually coextensive.

Abstract: An easily controllable method to adjust the die slot exit gap to produce an accurately controlled flow from the slot exit across the width of a die provides movable back seats at the back of the die that cause the front and back portions of the die plates to move simultaneously to produce a change in the die slot exit gap. At least one actuator is located between the front and back seats of the die to increase or reduce its length to bend the first plate around the front seat thereby to increase or decrease the first exit gap.

Abstract: A plurality of simultaneously applied coating fluids is coated on a substrate by moving the substrate along a path through a coating station. A plurality of flowing layers of coating fluid is formed in face-to-face contact with each other to form a composite layer. This composite layer flows at a speed that is sufficiently high to form a continuous flowing composite layer jet to the substrate surface for the coating width regardless of the direction of flow of the fluid jet.

Abstract: The method of coating a substrate with plurality of layers of coatings includes moving the substrate along a path through the coating station. A composite layer is formed of first and second coating fluids. The substrate contacts the flowing composite layer to interpose the first coating fluid between the substrate and the second coating fluid. The composite layer is doctored with a gas from a gas knife to remove some portion of the composite layer from the substrate.

Abstract: An apparatus and method of flowing a fluid onto an incline planar surface across the entire with of the slot has a slot capillary number less than 0.04. The slot exit gap S is selected to be less than ##EQU1## where S is the slot gap in cm, .mu. is the fluid viscosity measured in poise, .rho. is the liquid density measured in gm/cm.sup.3, .sigma. is the liquid surface tension measured in dyne/cm, and N.sub.re is the Reynolds number as defined by N.sub.re =4M/.mu., where M is the liquid flow rate per unit of width measured in gm/sec-cm. The expression for a is defined as 0.981+0.3406 log N.sub.re.sup.0.3406. The fluid is flowed through a slot exit.

Abstract: An easily controllable method to adjust a die slot exit gap to produce an accurately controlled flow from the slot exit across the width of a die provides movable back seats at the back of the die that cause front and back portions of die plates to move simultaneously to produce a change in the die slot exit gap. At least one actuator is located between the front and back seats of the die to increase or reduce the actuator length to bend the first plate around the front seat thereby to increase or decrease the first exit gap.