RU2743279C1 - Method of preparing metal surfaces of articles made from ferrous metals and stainless steels before applying polymer compositions in a flow and a viscous-flow state - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to the technology of preparing metal surfaces of articles made from ferrous metals and stainless steels prior to applying polymer compositions in a flow and a viscous-flow state onto the prepared surface. Metal surface of the item is cleaned from dirt and dust, a metal fine-mesh woven grid of black metal or stainless steel is welded to it by electric welding with wire thickness from 0.3 to 2.0 mm and cell size from 0.5×0.5 mm to 10.0×10.0 mm. Then said screen is attached to metal surface of item by means of electric rivets installed at distance of not more than 100 mm from each other. Electric rivets immediately after their welding are rolled-up in hot condition with casing onto metal woven mesh; then, degreasing of said mesh is performed.EFFECT: higher strength of adhesion of metal surfaces of articles made from ferrous metals and stainless steels with polymer compositions.1 cl, 6 dwg, 2 tbl, 16 ex

Description

The invention relates to a technology for the preparation of metal surfaces of products made of ferrous metals and stainless steels before applying polymer compositions to the prepared surface in a fluid or viscous-flow state.

Before applying the polymer composition, metal surfaces need preliminary preparation. There are two methods of pretreatment: chemical treatment and mechanical treatment. The main method of machining is shot blasting or sandblasting. The general method is to remove oxide scale, welding slag, rust, oil, etc. from the metal surface.

The known method of rubberizing metal products with rubber "Production of rubber technical products": textbook, manual / I.A. Ososhnik, Yu.F. Shutilin, O. V. Karmanova; under total. ed. Yu.F. Shutilina. - Voronezh, state. technol. acad. Voronezh, 2007.-972-p. (pp. 829-869). The essence of the method is that an adhesive (glue) is applied to the prepared metal surface, after which sheet rubber or liquid low molecular weight rubbers and latexes are applied to the adhesive layer. Then the vulcanization process is carried out. Moreover, special attention is paid to the preparation of the metal surface. In order for the adhesive to adhere to the metal and provide a strong bond between the metal and the polymer, it is necessary to create a branched surface. The main disadvantage of this method is the formation of an oxide film on the active surface of the metal after sandblasting or shot blasting, which prevents the adhesion of the metal with rubber. In the same source on page 843, it is recommended to apply the adhesive composition to the treated metal surface no later than 30 minutes later, in order to avoid the formation of an oxide film. This fact significantly hinders the provision of the proper quality of the gummed surface over large areas. It should also be noted that during the shot blasting of metal, in addition to the abrasive, hundreds of cubic meters of compressed air with a humidity of at least 60% falls on the metal, the oxygen of which, falling on the active surface cleaned with an abrasive, instantly reacts with the metal, forming oxides, which in turn significantly hinder the adhesion of the adhesive to the metal. The disadvantages of this method can also be attributed to the fact that shot blasting and sandblasting of metals provides only positive slopes on the surface (Fig. 2), which do not provide reliable fastening of rubber to metal, despite their branching.

The method of preliminary surface preparation by shot blasting or sandblasting of metal is used to obtain a branched surface on which a primer or adhesive is applied, which in turn provides a bond between the polymer and the metal (Fig. 1). This method of surface preparation has many disadvantages. Firstly, its use requires special, expensive sandblasting or shot-blasting equipment, the working parts of which (hoses, nozzles) quickly fail under the action of an abrasive. Secondly, to implement the method, a high-quality abrasive material is required, which is not cheap and its repeated use is not recommended, and it is quite problematic to clean the abrasive from dirt and grease, and is again associated with additional costs. Thirdly, in the process of sandblasting or shot blasting of a metal, hundreds of cubic meters of compressed air with an average humidity of 60% fall on its surface together with an abrasive, respectively, a large volume of an active metal surface is cleaned with an abrasive, the strongest oxidizer is oxygen, which promotes the formation of oxides, which, in turn, impede the adhesion of polymers to metal. Fourthly, with this treatment of the metal surface, it does not have negative slopes, which provide the greatest strength of the joint (Figure 2). Fifth, even after high-quality surface preparation of stainless steel by shot blasting or sandblasting, the adhesion of any polymers to stainless steel is much worse than to ferrous metals.

There is a known method for preparing products before applying the adhesive layer - RU 2544726, published 03/20/2015, which provides for the treatment of metal surfaces before applying the adhesive layer by oxidation in air at a temperature of 220-250 ° C for 20-30 minutes. The disadvantages of the above invention include the need for high-temperature processing of metal, which is not always applicable. For example, in the case of preparation of metal surfaces of a large area, such as tank equipment, railway tanks, etc., as well as in the case of preparation of the inner surface, when the outer side of the equipment already has a paint and varnish or other coating that is not able to withstand a temperature of 220 - 250 ° C. There are also difficulties associated with limited access to the processing area, as well as ensuring high productivity and economy. This method is the closest in essence to the proposed method and is taken as a prototype.

The task is to create a method to ensure reliable fastening of polymer coatings to ferrous metals and stainless steel.

The technical result is an increase in the adhesion strength of metal surfaces of articles made of ferrous metals and stainless steels with polymer compositions.

The technical result is achieved by the fact that the method of preparing metal surfaces of products made of ferrous metals or stainless steels before applying polymer compositions in a fluid and viscous-flowing state includes cleaning from dirt and dust, welding to a metal surface by electric welding of a fine-mesh metal mesh made of ferrous metal or stainless steel with a thickness wire from 0.3 to 2.0 mm and a mesh size from 0.5 x 0.5 mm to 10.0 x 10.0 mm, which is attached to the metal base using electric rivets and immediately after welding is expanded in a hot state, coining on a metal woven mesh, while the electric rivets are installed at a distance of no more than 100 mm from each other, after welding the metal fine-mesh woven mesh to the metal base, degrease it.

The difference between the claimed invention is a method of preparing the metal surface of products made of ferrous metals and stainless steels before applying a polymer composition by welding a metal woven mesh, which allows the polymer composition applied to a metal woven mesh in a fluid or viscous-flow state, after polymerization, to be retained on the metal not only for due to direct adhesion to the metal, and with the help of a metal woven mesh, which acts as an anchor, strengthened to the metal surface by means of hot-flared electric rivets, that is, mechanically. The metal woven mesh provides negative slopes for almost 50% of the mesh area. Accordingly, the polymer coating applied to the woven mesh in a fluid or viscous-flow state, after polymerization, is held with particular strength by the mesh surfaces having negative slopes (Fig. 3).

The method consists in the fact that the metal surface is cleaned of dirt and dust, a fine-mesh metal woven mesh made of ferrous metal or stainless steel is electrically welded to the metal surface of an article made of ferrous metal or stainless steel, the thickness of the wire and the size of the mesh of the metal woven mesh are selected from this calculation, to ensure reliable flow of the polymer through the cells into the mesh, welded to the base, in order to capture the mesh surfaces with a negative slope (Fig. 3), and the metal the woven mesh is attached to the metal base with the help of electric rivets, which, immediately after being welded to the metal of the counterbody (metal base), are expanded in a hot state, while stamping them onto the metal woven mesh. The mesh, in turn, is attached to the metal by a reliable electric riveting method with a step of no more than 100 mm. Moreover, the electric rivet is formed as follows: by electric welding, through a metal woven mesh, the base metal is point-welded, after which the hot rivet is immediately expanded with a hammer in such a way that the caulked top of the rivet captures the nearby wires of the metal woven mesh (Fig. 4). The wires of the mesh, when stamping, are firmly connected to the metal of the rivet by a forging joint and provide a strong connection of the woven mesh to the base (Fig. 5). After fixing the mesh, the mesh is degreased with solvents, then a polymer material is applied in a fluid or viscous-flow state (Fig. 6). As a metal woven mesh, a fine-mesh mesh made of ferrous metal or stainless steel is used, the wire thickness is from 0.3 to 2.0 mm, the mesh size of the woven mesh is 0.5x0.5 mm to 10.0x10.0 mm.

As a polymer material applied in a fluid or viscous-flow state to a prepared metal surface according to the method of the invention, various types of rubber mixtures dissolved in solvents to a fluid or viscous-flow state, two-component compounds of various nature (thermosets): polyurethane, polyester, epoxy, etc. also melts of thermoplastics: polyethylene, polypropylene, polyvinyl chloride, etc. The application of polymers in a flowing or viscous-flowing state is carried out by methods known in the art: by brush, roller, spatula, pouring, rotary method, spraying, etc.

Examples of the method are shown in table. one.

Table # 1. Examples of implementation of the method

No. Examples of implementation of the method Product surface material Metallic woven mesh Wire mesh thickness, mm Cell size, mm Electric rivet step, mm Additional degreasing one Black metal
Steel 3 Black metal
Steel 3 0.3 0.5x0.5 ten + 2 Black metal
Steel 3 Black metal
Steel 3 0.9 2.8x2.8 ten - 3 Black metal
Steel 3 Black metal
Steel 3 2.0 10.0x10.0 one hundred - four Stainless steel 12Х18Н10Т Stainless steel 12Х18Н10Т 0.3 0.5x0.5 ten + five Stainless steel 12Х18Н10Т Stainless steel 12Х18Н10Т 0.9 2.8x2.8 ten - 6 Stainless steel 12Х18Н10Т Stainless steel 12Х18Н10Т 2.0 10.0x10.0 one hundred + 7 Black metal
Steel 10 Black metal
Steel 10 0.3 0.5x0.5 ten - 8 Black metal
Steel 10 Black metal
Steel 10 0.9 2.8x2.8 ten - 9 Black metal
Steel 10 Black metal
Steel 10 2.0 10.0x10.0 one hundred + ten Stainless steel
12X18H9 Stainless steel
12X18H9 0.3 0.5x0.5 ten + eleven Stainless steel
12X18H9 Stainless steel
12X18H9 0.9 2.8x2.8 ten - 12 Stainless steel
12X18H9 Stainless steel
12X18H9 2.0 10.0x10.0 one hundred +

For clarity of the effectiveness of the proposed method, comparative tests were carried out. For this, the surface was first prepared according to the prototype method and the method of the claimed invention, respectively. All samples were prepared on paired steel plates 5x5x1 cm in size with a surface area of 5x5 cm - 25 cm². A polymer coating 1.5 mm thick was applied to one of the sides of two previously prepared paired metal plates with an area of 25 cm². Then both plates were connected side by side with a rubber compound glued to the metal and clamped with clamps. Then, polymerization was carried out in accordance with the technological recommendations for obtaining a polymer. To obtain a polymer coating, an elastomer was used in the form of a rubber mixture of sulfur vulcanization 51-1632 based on ethylene-propylene rubber and a harder polymer - polypropylene in granules. Both polymers do not have good adhesive properties.

Sample No. 1 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 3 steel, previously prepared by shot blasting and degreased, were applied in two layers Leukonat glue, after which a degreased calendered rubber compound 51-1632, thickness 1, was glued to each plate, 5 mm. Then both plates were connected side by side with a rubber compound glued to the metal and clamped with clamps. Then, the rubber mixture was vulcanized at a temperature of 150 ° C for 45 minutes.

Sample No. 2 was made in the following way. On one side with an area of 25 cm2, two paired plates made of stainless steel grade 12X18H10T, previously prepared by shot blasting and degreased, were applied in two layers Leukonat glue, after which a degreased calendered rubber compound 51-1632 with a thickness of 1.5 was glued to each plate mm. Then both plates were connected side by side with a rubber compound glued to the metal and clamped with clamps. Then, the rubber mixture was vulcanized at a temperature of 150 ° C for 45 minutes.

Sample No. 3 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 3 steel, previously prepared by shot blasting, degreased and heated to 180 ° C, a melt of polypropylene granules was applied in bulk at a temperature of 235 ° C with a thickness of 1.5 mm, after which the plates matched the sides with the applied polypropylene and allowed to cool to a temperature of 20 ° C.

Sample No. 4 was made in the following way. On one of the sides with an area of 25 cm², two paired plates made of stainless steel grade 12X18H10T, previously prepared by shot blasting, degreased and heated to 180 ° C, melted polypropylene granules at a temperature of 235 ° C with a thickness of 1.5 mm was applied, after which the plates were mated coated with polypropylene and allowed to cool to 20 ° C.

Sample No. 5 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal of grade 10 steel, previously prepared by shot blasting and degreased, were applied in two layers Leukonat glue, after which a degreased calendered rubber compound 51-1632, thickness 1, was glued to each plate, 5 mm. Then both plates were connected side by side with a rubber compound glued to the metal and clamped with clamps. Then, the rubber mixture was vulcanized at a temperature of 150 ° C for 45 minutes.

Sample No. 6 was made in the following way. On one side with an area of 25 cm², two paired plates made of stainless steel grade 12X18H9, previously prepared by shot blasting and degreased, were applied in two layers Leukonat glue, after which a degreased calendered rubber compound 51-1632 with a thickness of 1.5 was glued to each plate mm. Then both plates were connected side by side with a rubber compound glued to the metal and clamped with clamps. Then, the rubber mixture was vulcanized at a temperature of 150 ° C for 45 minutes.

Sample No. 7 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 10 steel, preliminarily prepared by shot blasting, degreased and heated to 180 ° С, a melt of polypropylene granules was applied in bulk at a temperature of 235 ° С with a thickness of 1.5 mm, after which the plates matched the sides with the applied polypropylene and allowed to cool to a temperature of 20 ° C.

Sample No. 8 was made in the following way. On one side with an area of 25 cm², two paired plates made of stainless steel grade 12X18H9, previously prepared by shot blasting, degreased and heated to 180 ° C, melted polypropylene granules at a temperature of 235 ° C with a thickness of 1.5 mm was applied, after which the plates were mated coated with polypropylene and allowed to cool to 20 ° C.

Sample No. 9 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 3 steel, a metal woven mesh made of ferrous metal grade 3 steel with a wire thickness of 0.9 mm and a mesh size of 2.8x2.8 mm, with a pitch of electric rivets of 10 mm was welded , then on the welded anchor mesh was applied with a brush, dissolved in a solvent nefras C2 80/120 rubber compound 51-1632 in a viscous-flowing state, flush with the upper edges of the mesh. After the rubber compound laid on the grid had dried to a “tack-free” state, a degreased calendered rubber compound 51-1632 with a thickness of 1.5 mm was glued to both plates. Then the plates were pressed by the rubber-coated surfaces and clamped with clamps. After that, the vulcanization of the rubber mixture was carried out at a temperature of 150 ° C for 45 minutes.

Sample No. 10 was made in the following way. On one side with an area of 25 cm², two paired plates of stainless steel grade 12X18H10T, a metal woven mesh made of stainless steel grade 12X18H10T with a wire thickness of 0.9 mm and a mesh size of 2.8x2.8 mm was welded according to the method of this invention, with a pitch of electric rivets 10 mm, the field of which on the welded anchor mesh was applied with a brush, dissolved in the solvent nefras C2 80/120 rubber compound 51-1632 in a viscous-flowing state, flush with the upper edges of the mesh. After the rubber compound laid on the grid had dried to a “tack-free” state, a degreased calendered rubber compound 51-1632 with a thickness of 1.5 mm was glued to both plates. Then the plates were pressed by the rubber-coated surfaces and clamped with clamps. After that, the vulcanization of the rubber mixture was carried out at a temperature of 150 ° C for 45 minutes.

Sample No. 11 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 3 steel, a metal woven mesh made of ferrous metal grade steel 3 with a wire thickness of 0.9 mm and a mesh size of 2.8x2.8 mm was welded according to the method of this invention, with an electric rivet pitch of 10 mm, the field of which on the welded anchor mesh, preheated together with the plate to 180 ° C, was applied in bulk, melt of polypropylene granules with a temperature of 235 ° C in a viscous state, 1.5 mm thick higher than the upper edges of the mesh. Then, both plates were paired, with the sides coated with polypropylene and allowed to cool to a temperature of 20 ° C.

Sample No. 12 was made in the following way. On one side with an area of 25 cm², two paired plates of stainless steel grade 12X18H10T, a metal woven mesh made of stainless steel grade 12X18H10T was welded according to the method of this invention, with a wire thickness of 0.9 mm and a mesh size of 2.8x2.8 mm, with a pitch an electric rivet 30 mm, the field of which on the welded anchor mesh, preheated together with the plate to 180 ° C, was applied in bulk, a melt of polypropylene granules with a temperature of 235 ° C in a viscous state, 1.5 mm thick higher than the upper edges of the mesh. Then, both plates were paired, with the sides coated with polypropylene and allowed to cool to a temperature of 20 ° C.

Sample No. 13 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 10 steel, a metal woven mesh made of ferrous metal grade 10 steel with a wire thickness of 0.9 mm and a mesh size of 2.8x2.8 mm, with an electric rivet pitch of 10 mm was welded , then on the welded anchor mesh was applied with a brush, dissolved in a solvent nefras C2 80/120 rubber compound 51-1632 in a viscous-flowing state, flush with the upper edges of the mesh. After the rubber compound laid on the grid had dried to a “tack-free” state, a degreased calendered rubber compound 51-1632 with a thickness of 1.5 mm was glued to both plates. Then the plates were pressed by the rubber-coated surfaces and clamped with clamps. After that, the vulcanization of the rubber mixture was carried out at a temperature of 150 ° C for 45 minutes.

Sample No. 14 was made in the following way. On one side with an area of 25 cm², two paired plates of stainless steel grade 12X18H9, a metal woven mesh made of stainless steel grade 12X18H9 with a wire thickness of 0.9 mm and a cell size of 2.8x2.8 mm was welded according to the method of this invention, with a pitch of electric rivets 10 mm, the field of which on the welded anchor mesh was applied with a brush, dissolved in the solvent nefras C2 80/120 rubber compound 51-1632 in a viscous-flowing state, flush with the upper edges of the mesh. After the rubber compound laid on the grid had dried to a “tack-free” state, a degreased calendered rubber compound 51-1632 with a thickness of 1.5 mm was glued to both plates. Then the plates were pressed by the rubber-coated surfaces and clamped with clamps. After that, the vulcanization of the rubber mixture was carried out at a temperature of 150 ° C for 45 minutes.

Sample No. 15 was made in the following way. On one side with an area of 25 cm², two paired plates of ferrous metal grade 10 steel, a metal woven mesh made of ferrous metal grade 10 steel with a wire thickness of 0.9 mm and a mesh size of 2.8x2.8 mm was welded according to the method of this invention, with an electric rivet pitch of 10 mm, the field of which on the welded anchor mesh, preheated together with the plate to 180 ° C, was applied in bulk, melt of polypropylene granules with a temperature of 235 ° C in a viscous state, 1.5 mm thick higher than the upper edges of the mesh. Then, both plates were paired, with the sides coated with polypropylene and allowed to cool to a temperature of 20 ° C.

Sample No. 16 was made in the following way. On one side with an area of 25 cm², two paired plates of stainless steel grade 12X18H9, a metal woven mesh made of stainless steel grade 12X18H9 was welded according to the method of this invention, with a wire thickness of 0.9 mm and a cell size of 2.8x2.8 mm, with a pitch an electric rivet 10 mm, the field of which on the welded anchor mesh, preheated together with the plate to 180 ° C, was applied in bulk, a melt of polypropylene granules with a temperature of 235 ° C in a viscous-flow state, 1.5 mm thick higher than the upper edges of the mesh. Then, both plates were paired, with the sides coated with polypropylene and allowed to cool to a temperature of 20 ° C.

After holding all the samples for 14 days, tests were carried out for the separation of polymers from metal in a tensile testing machine. The test results are recorded in Table 2.

Table 2. Comparative test results

Sample No. Surface preparation method Polymer Surface Breakout force (kgf) Bond strength of polymer with metal (kgf / cm²) Destruction nature one Prototype Rubber
51-1632 Steel 3 93.50 3.74 Adhesive 2 Rubber
51-1632 Steel 12Х18Н10Т 68.00 2.72 Adhesive 3 Polypropylene Steel 3 55,00 2.2 Adhesive four Polypropylene Steel 12Х18Н10Т 38.25 1.53 Adhesive five Rubber
51-1632 Steel 10 89.7 3.6 Adhesive 6 Rubber
51-1632 Steel 12Х18Н9 64.4 2.6 Adhesive 7 Polypropylene Steel 10 49.1 1.96 Adhesive 8 Polypropylene Steel 12Х18Н9 32.3 1.29 Adhesive 9 The claimed method Rubber 51-1632 Steel 3 2858 114.3 Cohesive ten Rubber 51-1632 Steel 12Х18Н10Т 2330 93.2 Cohesive eleven Polypropylene Steel 3 1282 51.3 Cohesive 12 Polypropylene Steel 12Х18Н10Т 1115 44.6 Cohesive thirteen Rubber 51-1632 Steel 10 2812 112.48 Cohesive 14 Rubber 51-1632 Steel 12Х18Н9 2291 91.64 Cohesive 15 Polypropylene Steel 10 1214 48.56 Cohesive 16 Polypropylene Steel 12Х18Н9 1073 42.92 Cohesive

According to the test results given in table. No. 2 shows that the force of separation of the samples according to the method of the present invention is ten times higher than the force of separation of the samples according to the method of the prototype.

Based on the foregoing, we can conclude the following: the set task of ensuring reliable attachment of polymers to metal according to the method of this invention is completed. Moreover, the method of this invention provides for the attachment to ferrous metals and stainless steel of polymer compositions that have low adhesion to metals and adhesives, or do not have it at all, for example: rubber based on EPDM rubber, polypropylene, etc. Due to the provision of durable mechanical fastening the anchor metal woven mesh by means of electric rivets flared onto the mesh ensured a strong connection of the polymer coating with the woven mesh using the negative slopes of the mesh, which, like an anchor, reliably hold the entire polymer coating (Table 2).

Terms used:

Positive slope of the surface - a slope that facilitates the recovery of the polymer applied to it.

Negative slope of the surface - the slope that prevents the extraction of the polymer applied to it.

Claims (2)

1. A method of preparing the metal surface of an article made of ferrous metals or stainless steels before applying polymer compositions in a fluid and viscous-flow state, characterized in that the metal surface of the article is cleaned of dirt and dust, a fine-mesh metal mesh made of ferrous metal or stainless steel is welded to it by electric welding with a wire thickness from 0.3 to 2.0 mm and a mesh size from 0.5 × 0.5 mm to 10.0 × 10.0 mm, attach the specified mesh to the metal surface of the product using electric rivets installed at a distance of no more 100 mm from each other, while the electric rivets, immediately after welding them, are expanded in a hot state with coining onto a metal woven mesh, after which the said mesh is degreased. 2. The method according to claim 1, characterized in that additional degreasing is carried out before welding the metal woven mesh.

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