RU2559010C1 - Method of manufacturing of bath for galvanic production - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention can be used during manufacturing of the bath for galvanic production with work electrolytes having neutral, alkali and acid environment working at temperature from -30 to +30°C, and washing baths of galvanic production, tanks for corrosive liquids and wastes drainage, storage and recycling. The method includes formation of the internal protective coating on the metal housing. The protective coating is made by PVC tape with adhesive layer installation on the internal bath surface, the adhesive layer is composition out of PVC resin and plastifier. At that initially tape is installed on the welds of the bath casing, on them preliminary glue BF-4 is applied with addition of the protector filler in amount of 25-30 parts by weight per 100 parts by weight of the glue, at that ultrafine zinc is used as the protector filler, the PVC tape is applied with adhesive layer over the entire bath surface overlapping joints of the previous layers by the successive tape layers.

EFFECT: assurance of effective bath corrosion protection, easy manufacturing and repair of bath with any dimensions upon presence of different holes for corrosion chemicals inlet-outlet.

1 dwg, 1 tbl, 1 ex

Description

The invention relates to the chemical industry, namely to bathtubs for cold galvanic production with working electrolytes having a neutral, alkaline and acidic environment, as well as to washing baths of galvanic production, tanks for dumping, storage and processing of aggressive liquids and waste.

Known bathtubs for galvanic production, containing a metal body and an internal protective coating - liner made of thermoplastic, for example, plastic or vinyl plastic: copyright certificates No. 983153, 1416530, 1477788; their main disadvantage is dimensional instability, which leads to “warping” of the protective liner. In case of local damage to the protective coating, complex repair is required.

Closest to the invention in technical essence is a bathtub for galvanic production and a method for its manufacture (RF patent No. 2404295 dated November 20, 10). The known bathtub includes a metal body with an internal protective coating made in the form of a layer of basalt plastic and coated with vinyl chloride enamel, including basalt filler. The method includes forming an inner coating on a metal case, wherein the protective coating is formed by applying basalt fabric on a raw epoxy putty previously applied to the inner surface of the body with an overlap at the weld joints, impregnating the overlays with said putty and then applying vinyl enamel, including basalt filler.

The disadvantage of this design is that during operation in aggressive environments, “chalking” of vinyl enamel and diffusion of the aggressive medium to the border “epoxy primer-putty - basalt filler” is observed, which leads to the destruction of the protective coating and, accordingly, to shorten the life of the structure bathtubs.

The technical task of this invention is to provide effective protection of the bath from corrosion, ease of manufacture, transportation and repair of the bath or container of any size and in the presence of any openings for input-output of aggressive liquids and reagents.

The technical result is achieved in that the protective coating is formed by laying on the inner surface of the bath a polyvinyl chloride tape with an adhesive layer, which is a composition of polyvinyl chloride resin and a plasticizer, for example, according to TU 2245-001-00203312-2003, while the tape is first laid out on the welds the body of the bath, on which BF-4 glue is previously applied with the addition of a tread filler in an amount of 25-30 wt. hours per 100 wt. hours of glue, moreover, ultrafine zinc is used as a tread filler, then a polyvinyl chloride tape with an adhesive layer is laid on the entire surface of the bath, overlapping the joints of the previous layers with subsequent layers of the tape.

A chemically resistant multilayer coating is formed by laying out a polyvinyl chloride tape with an adhesive layer. A PVC tape with an adhesive layer is a base film made of a PVC composition by a roll-calender method, with an adhesive layer deposited on one side, cut into strips of a certain thickness. A PVC tape with an adhesive layer has no holes, bubbles, cracks, gaps in the adhesive layer over its entire area and tears at the edges. The adhesive layer does not peel off when rewinding the roll and does not pass to the other side of the tape. The surface of the roll is smooth. As a result of laying a PVC tape with an adhesive layer on the entire surface of the bath, a protective coating is obtained that is resistant to aggressive environments, requiring virtually no repair work. The temperature range of operation of the tape in static conditions is from -30 to + 30 ° C.

BF-4 glue with the addition of ultrafine zinc has high adhesive properties, creates a chemically resistant film on the surface of the seams, thereby ensuring the resistance of welds from chemical attack.

The table shows the experimental data on the dependence of the parameters of the adhesive BF-4 on the amount of filler - ultrafine zinc.

Table Options Prescription composition BF-4 with wt. h. ZnO 15-20 25-30 35-50 Adhesion to metal, score one one 2 Chemical resistance to NaOH (3%) unstable steady steady Moisture absorption,% 1,2 10.5 10.6 Adhesion of PVC to glue BF-4 (peeling), kgf / cm 6.9 9.5 7.5

As can be seen from the table, the combination of the most effective is the formulation using 25-30 wt. including ultrafine zinc per 100 wt. h. BF-4 glue, which is compatible with PVC material.

In FIG. The developed scheme of a protective coating is shown, where the following designations are accepted:

1 - metal body of the bath,

2 - weld,

3 - glue BF-4 (with ultrafine zinc),

4 - polyvinyl chloride material (7 layers δ = 4-5 mm in total).

An example of a protective coating

Two layers of glue 3 (BF-4 glue with the addition of ultrafine zinc) are applied with a brush to the welds 2 of the metal body of the bathtub 1, pre-cleaned from corrosion, and dried to dry completely for 1 hour at a temperature of 15 to 35 ° C. Next, on a prepared surface of the welds 2, a PVC tape with an adhesive layer 4 of 200-300 mm is glued to the weld 2 on each side, without a joint in the weld, then a PVC tape with an adhesive layer 4 is laid on the entire surface of the bath 1 in 7 layers ( δ = 4-5 mm in total), each subsequent layer overlaps the joints of the previous one. Dry the coating for at least 24 hours.

EFFECT: invention provides effective protection of the bathtub against corrosion, repeats any geometry of the bath’s internal surfaces - the bottom and side walls, ease of execution, reduces the technological cycle of coating production, repair of the bathtub or container of any size, in the presence of any openings for input-output of aggressive liquids and reagents and increases the technical level of production.

Claims (1)

A method of manufacturing a bath for galvanic production, including the formation of an internal protective coating on a metal casing, characterized in that the protective coating is formed by spreading on the inner surface of the bath a polyvinyl chloride tape with an adhesive layer, which is a composition of polyvinyl chloride resin and plasticizer, with the tape first being laid on welds of the bath body, on which BF-4 glue is preliminarily applied with the addition of tread filler in the amount of 25-30 wt. per 100 wt. including glue, moreover, ultrafine zinc is used as a tread filler, then a polyvinyl chloride tape with an adhesive layer is laid on the entire surface of the bath with overlapping joints of previous layers with subsequent layers of the tape.

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