Method of making the layers from the resins ,plasts,cements etc. on the whole or portion of the semiproduct

(54) A method of forming resins, plastics, sealants, etc. on all or part of a preform

The invention relates to a process for the simple and undemanding formation of layers of resins, plastics, sealants, etc. on glass, metal, plastic, etc. blanks.

Previously known methods of dispensing powder onto β / blanks are based on the fact that powder is metered onto the blanks through a sieve, eg vibrating screen. This method allows the blank to be kept cold. The disadvantage is that the dosing accuracy is low, the powder swirls even at places that we do not want to coat, and the further heat treatment, for example thermoplastics, results in tackiness of the substrate and small blanks, making the process unusable for these blanks. and

The most common dosing method is a process in which the preform is heated and immersed in a powder layer, i; This method is possible where high purity of the areas we do not want to coat is not required. The disadvantage is that it requires heat energy for heating, which is considerable for large bodies, while for small bodies, the semi-finished products are rapidly cooled and thus dosing inaccuracies.

Less frequent is also the method of wiping suitable for large products, in which the semifinished product is dosed with a larger amount of powder and wiping the bar creates a_: imported thickness of the powder layer. The disadvantage is the inapplicability for small products as it would to fill them with powder.

Another method is the electrostatic powder coating method, which is suitable for application to the entire product, holding the powder on the semi-finished product by means of an electric charge until heat treated. The disadvantage is the relatively expensive and demanding equipment for this method and further that it is not possible to form partial powder coatings on the product.

Neither of these methods is suitable for small products and for the application of powder to a portion of the small blanks or group of small blanks.

All these drawbacks are overcome by the method according to the invention, which first comprises applying a liquid, for example water, an alcohol solution, to the workpiece surface or part thereof, and then contacting the treated surface with powder and dispensing it with powder. The powder coated blank is heated until the liquid evaporates or until the powder layer melts. The coating liquid may contain the powder to be dosed at a concentration of from 1 to 95% by weight, or a solvent, for example, alcohol at a concentration of from 0.01 to 90% by weight or a wetting agent, for example based on dialkyl sulphate succinate. When dispensing powder onto a portion of the blanks, the blanks can be fixed

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by vacuum so that the surfaces of all the blanks to be applied are flush with each other throughout the application.

An advantage of embodiments of the invention is that the process of deposition of the fastening layer is carried out cold, which greatly simplifies the whole process, makes it possible in the case of small products to carry them out at all, since There is also an energy saving as there is no need for double heating - the product for applying the fastening layer and the whole product and the fastening layer to melt it and attach it to the product, or to attach the whole product to the next layer or semi-finished product. Furthermore, the liquid has the advantage that by pressing it against the fastener powder, it is: firstly spread over the surface of the product and | ensures even powder dosing. The liquid is preferably a solution of various surface wetting agents. In the case of partial refinement, the small products can preferably be sucked in by means of a vacuum and all the depositing operations can be carried out up to the time of one fixing, while ensuring the cleanliness of both the suction agent and the other areas not refined on the product. This makes it possible to process even very inaccurate blanks, since the fastening secures the plane of all the lower parts of the blanks, thereby ensuring, for example, the same coating height on the blanks.

Semi-finished products can be made of various materials such as glass, metal, plastic, etc.

The applicability of the invention is very broad, since it can replace all methods of heat metering or complex machine dosing of melts or powders - sealants, adhesives, resins including fillers, etc.

In the accompanying drawing, the principle of the invention is schematically shown, in which Fig. 1a shows a cross-section of a semi-finished product with a liquid coating, Fig. 1b shows a cross-section of a semi-finished product with powdered layer; .

According to FIG. 1a, the glass ball 1 attached to the sealant 4 by vacuum is partially immersed in water with the addition of 1 wt. Thus, after removal from the water 2 on the submerged portion of the glass ball 1, a layer or drop of water 2 is formed. % of powder 3, for example polyethylene, or 1 wt. alcohol.

The glass ball 1 thus treated is immersed in a layer of powder 3, for example polyethylene (Fig. 1b), under a single pressure clamping on the binder 4, whereby the quantity of powder 3 is fixed on the surface according to the amount of water 2.

The treated glass bead 1 is heated according to FIG. 1c by a heat source 5 at 200 ° C for 60 s, thereby evaporating water 2 and melting the polyethylene powder layer, then releasing the vacuum and forming a layer of polyethylene on the part of the glass bead 1. .

In the case of a plurality of particularly inaccurate glass beads 1 according to FIG. 2, the procedure is similar, except that the movement and fixation of the sealants 4 ensures a plane of undersides of the glass beads 1, which ensures a layer of polyethylene to the same height on all glass beads.