FR2699557A1 - Method of protecting an electroplating tool and the product obtained - Google Patents

Abstract

The invention relates to a method for protecting an electroplating tool and a product obtained by this method, as well as a device for implementing the method. The tooling is protected in the form of a coating comprising at least two layers of different plastics from the plastisol family. The tool thus obtained is protected by two or more layers of plastisols (3, 4), the outer layer (4) of which is harder than the other layer (s) (3). The device for implementing the method comprises a plurality of work stations, each of which corresponds to a step of the method.

Description

The invention relates to a method for protecting a tool of

  The invention also relates to an electroplating device and a product obtained by this method.

  implementation of the method of the invention.

  The method of the invention consists more particularly in the application of a coating comprising at least two layers of different plastics on a tool for electroplating Plastics

  used belong to the plastisol family.

  Plastisols are mixtures of a powdered vinyl resin suspension prepared by the emulsion polymerization (or microsuspension) process in a liquid plasticizer, and adjuvants, such as stabilizers, fillers, pigments, blowing agents and the like. Adjuvants Under the action of heat, plastisols

  transform into homogeneous solids.

  The vinyl resins used to obtain plastisols are mainly polyvinyl acetate, polyvinyl ether, polyvinyl alcohol and polyvinyl chloride (PVC). For electroplating, we use

  essentially poly (vinyl chloride) (PVC>.

  Electroplating equipment includes all kinds of electrolysis fixtures, intended to maintain the parts that one wishes to chromise, nickeler or to coat with any metal, or that one wishes, on the contrary to demetallize the pieces plunge into chemically corrosive baths such as sulfochromatic, hydrochloric, nickel plating, chemical copper plating, chromium plating, gilding baths,

  silvering, demetallization or the like.

  French patent FR-2,556,131 describes a plastisol

  used for the coating of electrolysis fixtures.

  Previously, this plastisol made it possible to obtain sufficiently satisfactory coatings insofar as they had both sufficient mechanical or physical impact resistance and sufficient protection against

  corrosion, for the usual conditions of galvanization.

  However, changes in both galvanizing currents applied and in terms of the composition of the baths used, resulted in insufficient protection of the tool which is manifested in particular by premature cracking of the coating of the tools in general and springs in particular, due to a

excessive hardening of the plastisol.

  The object of the invention is to improve the plastisol coating of an electroplating tool in order to overcome

the disadvantages noted.

  The object of the invention is achieved by a method of protecting an electroplating tool by at least two

  plastic layers of the plastisol family.

  This process comprises the following steps: a) cleaning and degreasing of the tooling, b) application of an undercoat of adhesion to the tooling, c) steaming of the tooling, d) dipping of the tooling in a bath of a first plastisol, e) drip and drying of the tool, f) steaming of the tool of a duration such that there is no complete gelation of the first plastisol, g) soaking of the tooling in a bath of a second plastisol of a hardness, after polymerization, greater than that of the first plastisol, h) drip and drying of the tool, i) steaming of the tool until complete gelation

second plastisol.

  The particular conditions of the parboiling of the tooling after the application of the first layer of plastisol, namely the fact of avoiding a complete gelation of this layer, are intended to ensure an optimal bond between the first layer, or layer interior, plastisol

  and the second layer, or outer layer, of plastisol.

  This intimate bond or fusion is important because it allows the plasticizers contained in the inner layer of plastisol, to migrate, when using the tool,

  to the outer layer of plastisol.

  The refilling of the outer layer of plasticizers from the inner plastisol layer makes it possible to avoid porosity and loss of the elasticity of the coating, due to the loss of plasticizers occurring during

  the use of known plastisol coatings.

  The method of the invention is not limited to an application of two layers of plastisol On the contrary, it is also possible to apply more than one inner layer of plastisol The essential is that the inner layers, whether they are made in one or more different plastisols, each have a hardness, after polymerization,

  less than that of the outer layer of plastisol.

  Regardless of the total number of layers of plastisol applied, the method of the invention makes it possible, by the flexibility or flexibility of the inner layers, to provide very good protection for the tooling and in particular for the springs or the supply of currents against the mechanical stresses. of use in electroplating, and, at the same time, by the hardness of the outer layer, a very good strength of the tool against the increased chemical aggressiveness of galvanizing baths currently used The improvement in chemical resistance is more particularly important for the springs of the tool, because the porosity of their coatings found in the prior art favored

  metal deposition on the coatings.

  The plastisols chosen for a particular embodiment of a coating according to the invention may contain different kinds of vinyl resin. Alternatively, the plastisols of the different layers may be prepared from the same vinyl resin.

  Preferably, polyvinyl chloride (PVC) will be used.

  The invention also relates to a method for protecting an electroplating tool, having the following characteristics, considered individually or in all their technically possible combinations: the soaking steps of the tooling in a bath of a first plastisol, drip and drying of the tooling, and the parboiling of the tooling of a duration such that there is no complete gelation of the plastisol, are repeated at least once with at least a third plastisol before proceeding to the dipping steps of the tooling in the bath of the second plastisol, drip and drying of the tooling, and steaming of the tooling until complete gelation of the second plastisol; the baking of the tooling which is carried out after the application of an adhesion sub-layer, is carried out at a temperature between 170-C and 190 C; the steaming of the tooling which is carried out after dripping and drying of the tool having been coated with a layer of plastisol other than the second layer (outer layer), is carried out at a temperature of between C and 170 ° C. for 15 to 20 minutes; the steaming of the tool after application of a layer of the second plastisol, that is to say after application of the outer layer of the coating, is carried out at a temperature of between 180 ° C. and 200 ° C. for 30 to 35 ° C. minutes; the steaming of the tool after application of the outer layer is often carried out in two phases, the first being constituted by the rise in temperature of the oven to a temperature between 160-C and 200 ° C, which lasts 15 to 20 minutes, and the second is a temperature of between 180 ° C and 200 ° C applied for 30 minutes.

at 35 minutes.

  the various steps of the process of the invention, and in particular the application of a first layer of a first plastisol, the drip and drying of the tooling, and the baking of the tooling without complete gelation of the layer of plastisol, a possible repetition at least once of these stages with at least a third plastisol, as well as the steps of applying a layer of a second plastisol constituting the outer layer of the coating of the tool, the drip and the drying of the tooling, and the parboiling of the tooling until complete gelation of the second plastisol constituting the outer layer of the coating, are carried out one after the other without

  noticeable pause between the different stages.

  However, it is conceivable, without departing from the scope of the invention, to carry out the various steps of the method of the invention at significant time intervals. This can occur, for example, when the method has to be implemented by means of of an installation comprising only one tank for plastisols In such a situation, it is inevitable to introduce breaks after application and baking of a layer to all the tools provided if the realization of the next layer requires a bath change. However, it should be noted that gelation started

  does not stop when the tool is out of the oven.

  This entails the risk of adhesion or fusion of lesser quality of this layer with the next layer and, by this, a reduction of the plasticizer migration capacity of the lower layer (s) towards the outer layer of

plastisol.

  The invention also relates to an electroplating tool protected by a first layer of a first plastisol and which is coated with at least a second layer of a second plastisol, the second plastisol being of a hardness, after polymerization, greater than that of the first plastisol. The electroplating tool according to the invention may also have the following characteristics, considered individually or in all their technically possible combinations: the first plastisol has a hardness, after polymerization, of 55 to 70 Shore A; the second plastisol has a hardness, after polymerization, of 70 to 90 Shore A; the first plastisol and the third plastisol are identical. The invention also relates to a device for implementing the method of the invention. This device comprises a first workstation intended for cleaning and degreasing the tooling, a second workstation intended for the application of the invention. an undercoating layer on the tooling, a third work station comprising a first tank intended to contain a first plastisol, at least a fourth work station comprising at least a second tank intended to contain a second plastisol, and the

  minus another workstation with an oven.

  It is understood that the number of work stations with a tank as well as the number of workstations with an oven is variable according to each particular embodiment Thus, an optimal installation will include, for example, a number of workstations having an oven equal to the total number of work stations intended for the preparation of the tools and the application of the adhesion sub-layer and the

layers of plastisol.

  In what follows, the invention will be described using two embodiments of the method according to the invention, an embodiment of a tool according to the invention and an embodiment of a setting device

  Process of the process according to the invention The description is made

  with reference to the drawings, in which: Figure 1 shows, in a very schematic section, a tool for electroplating, and Figure 2 shows a very schematic representation of a workstation layout of a device for

  the implementation of the method according to the invention.

EXAMPLE I

  Plastisol double layer coating The process involves the following steps: a) Tooling preparation: Sandblasting, degreasing with trichlore vapor, rinsing with water and drying; b) spray application of an undercoat adhesion to the tooling followed by drying the coating for 15 minutes at room temperature; c) preheating the equipment in an oven at a temperature between 180 and 200 ° C for 30 minutes; d) dipping the hot tool in the bath of a first plastisol; this first plastisol comprises, in addition to polyvinyl chloride (PVC), a plasticizer system consisting of octyl phthalate and octyl adipate and representing 60% by weight relative to PVC, a thixotropic mixture consisting of esters of hexylene glycol, benzyl alcohol, turpentine and petroleum, and organic tin salts; e) the tool is drained very slowly out of said bath at a speed between 1 and 5 cm / minute; slow drip is important to obtain a thin and homogeneous coating without sagging; f) the dried equipment is heated in an oven at 160 ° C for 15 minutes; g) the tool is then dipped in a bath of a second plastisol; this second plastisol comprises, in addition to polyvinyl chloride (PVC), a plasticizer system consisting of octyl phthalate and octyl adipate and representing 45% by weight relative to the PVC; a thixotropic mixture consisting of esters, hexylene glycol, benzyl alcohol, turpentine and petrol; and organic salts of tin; h) the tool is drained very slowly by taking it out of said bath at a speed of between 1 and 5 cm / minute; i) Steaming the tool at a temperature of 160 ° C for minutes and then at a temperature of 180 C for 30 minutes. EXAMPLE II Plastisol triple layer coating The method comprises the following steps: a) Preparation of the tooling: sandblasting, degreasing using a bath of sodium hydroxide solution, rinsing with water and drying; b) applying an undercoat adhesion to the tooling by dipping in a bath of a corresponding primer, followed by drying the coating for 15 minutes at room temperature; c) preheating the equipment in an oven at a temperature between 180 and 200 C for 30 minutes; d) the hot tool is immersed in the bath of a first plastisol; this first plastisol comprises, in addition to polyvinyl chloride (PVC), a plasticizer system consisting of octyl phthalate and octyl adipate and representing 60% by weight relative to PVC, a thixotropic mixture consisting of esters of hexylene glycol, benzyl alcohol, turpentine and petroleum, and organic tin salts; e) the tool is drained very slowly out of said bath at a speed between 1 and 5 cm / minute; f) the dried equipment is heated in an oven at 160 ° C

for 15 minutes.

  g) steps d), e) and f) are repeated once to obtain an additional layer of the first plastisol; h) the tool is then dipped in a bath of a second plastisol; this second plastisol comprises, in addition to polyvinyl chloride (PVC), a plasticizer system consisting of octyl phthalate and octyl adipate and representing 45% by weight relative to the PVC; a thixotropic mixture consisting of esters, hexylene glycol, benzyl alcohol, turpentine and petrol; and organic salts of tin; i) the tool is drained very slowly out of said bath at a speed between 1 and 5 cm / minute; j) Steaming the tool at a temperature of 160 ° C for minutes and then at a temperature of 180 C for 30 minutes. Figure 1 shows, in a very schematic cut, a tool obtained by means of the method according to Example I. The tool 1 is a basket in which are placed objects to be coated with a metal The tooling can also be an electrolysis assembly to which are attached, during their galvanizing, various parts,

or any other suitable medium.

  Basket 1 is covered on its entire surface, that is,

  that is to say on the inner surface as well as on the external surface, of an adhesion sub-layer 2 which, itself, is covered with a first layer 3 of a first plastisol On the layer 3 of the first plastisol is filed a second

layer 4 of a second plastisol.

  The first layer of plastisol and the second layer of plastisol differ from each other, on the one hand, by their hardness after polymerization and, advantageously on the other hand, by their color. The particular color of each plastisol is obtained by an additive that does not cause a reaction

  chemical with the other components of the mixture.

  FIG. 2 shows, in a representation that is also very schematic, an installation constituting a device for implementing the method of the invention according to example II. For the purposes of a simplified representation, the appearance of an optimal arrangement some issues

  elements of the device was intentionally omitted.

  The device for implementing the method of the invention comprises a first work station 5 intended for the preparation of the tooling 1 according to the rules of the art known per se. The workstation 5 comprises means 6 necessary to be able to perform a task. sanding tool 1, and a rinsing tank 7 in which the tooling

1 is immersed after sanding.

  It is understood that the first work station can comprise either instead of or in addition to sanding means 6, a tank (not shown) for chemical degreasing using trichlor fumes or a

solvent.

  The device for implementing the method according to the invention also comprises a second work station 8 intended for the application of the adhesion sub-layer. The second work station 8 is represented schematically by a vessel containing a suitable primer L application of the primary to the tooling 1 may, however, also be

by brush or spray.

  The device for implementing the method according to the invention also comprises a third work station 9, a fourth work station 10 and a fifth work station 11 The third, fourth and fifth work stations are intended for the application of the first layer 3 of plastisol, the second layer 4 of plastisol and the third plastisol layer (not shown in FIG. 1) Each of the work stations 9, 10 and 11 is represented by a tank containing the

corresponding plastisol.

  As a variant of the configuration stated above, the tank of the third work station 9 can be replaced by electrostatic guns to be able to

  apply the first layer of plastisol to the gun.

  The device for implementing the method according to the invention also comprises a sixth work station constituted by an oven 12 in which the tooling

  i is heated according to the different steps of the process.

  To facilitate the transport of the tool 1 from one work station to another, a transport and maintenance means, represented by a rail 13 on which a carriage 14

can be moved, is expected.

  The reference signs inserted after the characteristics

  technical features mentioned in the claims, have

  for the sole purpose of facilitating the understanding of the latter,

  and in no way limit its scope.

Claims (9)

  A method of protecting an electroplating tool, characterized by applying at least two layers of plastics of the plastisol family, the method comprising the following steps: a) cleaning and degreasing of the tooling, b) application of an undercoat of adhesion on the tooling, c) steaming of the tooling, d) soaking of the tooling in a bath of a first plastisol, e) drip and drying of the tooling, f) steaming of the tooling of a duration such that there is no complete gelation of the first plastisol, g) soaking of the tool in a bath of a second plastisol of a hardness, after polymerization, greater than that of the first plastisol, h) drip and drying of the tooling, i) steaming of the tool until complete gelation of the second plastisol.   Process according to claim 1, characterized in that steps d) to f) are repeated at least once with at least one third plastisol, before proceeding to steps g) to i).   Process according to any one of claims 1   and 2, characterized in that the parboiling of step c) is   carried out at a temperature between 170-C and 190-C.   4 Process according to any one of claims 1   at 3, characterized in that the stoving of step f) is carried out at a temperature between 150 and 170 ° C for 15 to 20 minutes.   Process according to any one of claims 1   at 4, characterized in that the stoving of step i) is carried out at at least one temperature level, the highest level not exceeding a temperature between   180 ° C and 200 ° C, applied for 30 to 35 minutes.   Process according to any one of claims 1   at 5, characterized in that steps d) to f), their at least one possible repetition, and steps g) to i) are performed one after the other without significant pause between the different steps. Electroplating tool (1) protected by a first layer (3) of a first plastisol, characterized in that the tool (1) is coated with at least a second layer (4) of a second plastisol, the second plastisol having a hardness, after polymerization, greater than that of the first plastisol. 8 Tooling according to claim 7, characterized in that the first plastisol has a hardness, after polymerization, between 55 and 70 Shore A. 9 Tooling according to claim 7 or 8, characterized in that the second plastisol has a hardness, after polymerization between 70 and 90 Shore A.   Tooling according to any one of the claims   7 to 9, characterized in that the first plastisol and the   third plastisol are identical.   11 Apparatus for implementing the method of protecting a galvaloplasty tool (1) according to one of   any of claims 1 to 6,   comprising a first work station (5) for cleaning and degreasing the tool (1), a second work station (8) for applying a bonding sub-layer to the tool, a third work station (9) having a first tank for holding a first plastisol, at least a fourth work station (11) having at least a second tank for holding a second plastisol, and at least one other work station ( 12) having an oven.