Abstract:
Method of coating cores of pharmaceutical tablets with a dry powder, wherein the cores are fed onto a conveyor, the dry powder is supplied to a region through which the cores are to be conveyed, and the cores are conveyed on the conveyor through the region with the cores maintained at a different electric potential from the dry powder. In this way, the dry powder is attracted to the exposed surfaces of the cores to form powder coatings thereon. The dry powder on the surface of the cores is then melted to convert the powder into fused film coatings secured to the cores.
Abstract:
An electrostatic powder coating apparatus comprising a powder reservoir, a gas flow injection chamber, a diffusion chamber and a coating chamber and method for coating a substrate or target objects. The injection chamber receives powder from the reservoir at a controlled rate. The powder particulates are entrained by a gas flow within the injection chamber. The diffusion chamber receives the particulates from the injection chamber. The diffusion chamber deaccelerates the particulates and creates a particulate cloud. The coating chamber receives the particulate cloud. A housing encloses the coating chamber. The coating chamber is isolated from the ambient atmosphere. The coating chamber has a cloud inlet and a cloud outlet. The cloud flows through the coating chamber from the inlet to the outlet. One or more deflectors, within the chamber, define a passage and two or more pockets adjoining the substrate or target objects. The deflectors deflect the carrier gas from the pockets to the substrate or target objects. The substrate or target objects are transported within the chamber along the passage. Coating material within the passage is concentrated around the substrate or target objects. The coating chamber includes electrodes and voltage biasing means. The biasing means acts upon the substrate or target objects which are positioned within the passage. The particulates are electrostatically deposited upon the substrate or target objects within the passage.
Abstract:
An electrostatical powder coating method starts out from a metallic surface provided with an oil film as a protection against corrosion during storing and transportation. Resin powder is applied to the surface without prior removal of the oil film. The powder layer is melted in a furnace and subsequently hardened by cooling. It is preferred that an amount of heat is supplied by the furnace which is sufficient to evaporate the oil. Preferably, an oil is used which is stable during heating as long as it remains on the work piece surface. This includes the possibility that all of the oil or at least some components thereof diffuse and evaporate through the powder layer during heating or, alternatively, that part or all of the oil remains on the work piece during the heat treatment and mixes with the powder layer. In both cases the quality of the resin coating is not deteriorated by the oil film.
Abstract:
An apparatus for applying a coating of solid particulate powder to the interior surface of tubular, cylindrical articles includes a conveyor for transporting the articles to and from a powder spray station whereat powder is sprayed into one open end of the articles. The conveyor includes an endless belt conveyor movable in a direction perpendicular to the spray from the nozzle and the axes of articles supported on the conveyor. The articles are supported on the conveyor by lugs in the form of rollers which support the articles in grooves defined between adjacent pairs of lugs.
Abstract:
Apparatus (74) and method are provided for electrostatically depositing particles (64) of a first material onto a sheet (18) of a second material. The apparatus (74) includes an accelerating and directing passageway (96) that is formed by a deflector (82) and one end (54) of a depositing chamber (78), and an accelerating electrode (90) that is disposed in the passageway (96). The accelerating electrode (90) and the passageway (96) cooperate to accelerate particles (64) in the depositing chamber (78) and to direct them into electrostatic depositing contact with the sheet (18).
Abstract:
A method for electrostatically depositing a first material, such as a lubricant, onto a second material where the first material comprises particles ranging in size from smaller to larger. The method comprises depositing the smaller particles of the first material onto adjacent portions of the second material moving through a depositing chamber and progressively depositing the larger particles of the first material onto the adjacent portions of the second material generally subsequent to the first depositing step.
Abstract:
There is provided a method for coating a metal substrate by the use of a polyvinylidene fluoride resin composition. The method comprises forming a coating film made of a melted resin composition on the surface of an undercoated metal substrate at a temperature of from 200.degree. to 350.degree. C., said resin composition containing a major amount of polyvinylidene fluoride and from 5 to 40% by weight of an inorganic filler based on the total weight of the resin composition; and precooling said coating film to a temperature T.sub.A and then keeping said coating film at the temperature T.sub.A for at least one minute, wherein said temperature T.sub.A (.degree.C.) satisfies the inequality:T.sub.C -10.degree.C..ltoreq.T.sub.A .ltoreq.T.sub.C +10.degree.C.,said T.sub.C (.degree.C.) being the crystallization temperature for the polyvinylidene fluoride.
Abstract:
Light-absorbing particles are selectively applied to a lenticular light-transmissive screen, such as a projection television screen. The particles are selectively deposited in grooves between lenticules of the screen by filling the grooves to a predetermined depth with a slurry comprising a mixture of a volatile liquid and the light-absorbing particles. Microwave radiation is applied to the screen with the deposited particles, to effect evaporation of any unevaporated liquid and fusing of the particles to each other and to the screen.
Abstract:
A powder coating composition comprising a homopolymer or copolymer of polyvinylidene fluoride having a melt flow index of 10 to 300 grams per ten minutes, determined in accordance with ASTM D 1238, Condition J and 5 to 50 weight percent of a glass having a grain size of 1 to 300 .mu.m; an improvement in a method of coating a metal or inorganic oxidic surface wherein a powder coating composition containing polyvinylidene fluoride is applied to such surface and fused thereon, the improvement residing in employing as the powder coating composition one containing 5 to 50 weight percent glass, based upon the weight of the polyvinylidene fluoride polymer; a coated object having a metallic or inorganic oxidic surface which is coated with a polyvinylidene fluoride homopolymer or copolymer which coating contains 5 to 50 weight percent, based upon the weight of the polyvinylidene fluoride, of glass particles, especially glass particles of a grain size of 1 to 300 .mu.m.
Abstract translation:一种粉末涂料组合物,其包含熔体流动指数为10至300克/ 10分钟的聚偏二氟乙烯的均聚物或共聚物,其根据ASTM D 1238,条件J和5至50重量%的晶粒尺寸为 1〜300亩; 涂覆金属或无机氧化物表面的方法的改进,其中将含有聚偏二氟乙烯的粉末涂料组合物施用于这种表面并在其上熔融,其改进在于使用含有5至50重量%玻璃基的粉末涂料组合物 以聚偏二氟乙烯聚合物的重量计; 具有金属或无机氧化物表面的被覆物体,其涂覆有聚偏二氟乙烯均聚物或共聚物,该涂层含有基于聚偏二氟乙烯重量的5-50重量%的玻璃颗粒,特别是玻璃颗粒的玻璃颗粒, 1〜300亩。
Abstract:
Improved electrostatic coating is obtained by heat-rounding or spheroidizing pulverized resin particles so that 30-80% take on a glossy appearance while the rest remain rough to provide a mixture that is free flowing at ordinary room temperature and would pass through a screen having openings not exceeding 200 micrometers. Preferably each particle of the mixture is a blend of thermosetting resin and curing agent.