DE1075022B - Process for improving the adhesion of plasticizer-containing polyvinyl chloride coatings to metals by means of an organic adhesive layer - Google Patents

Description

GERMAN

As is known, the polyvinyl chloride has in recent years as a material for the production of chemical Apparatus that have to withstand the corrosive action of acids, gases, etc. is of great importance obtained, in addition to its use in the manufacture of tubes, cooling coils, containers, etc., for which one uses polyvinyl chloride of the so-called hard type. Although this material in many Cases shows excellent corrosion resistance, its mechanical properties do not allow it in all cases its sole use as a material. His is especially sufficient for certain purposes Notch toughness does not matter. To overcome these difficulties, this material has been proposed not to be used on its own, but to line metallic tubes, apparatus, etc. with it.

The covering of metallic surfaces with polyvinyl chloride films, however, offers considerable benefits in practice Difficulties, the main difficulty is getting the polyvinyl chloride to adhere adequately to achieve on the metal, which is maintained even during operation, so detachment and deformation of the polyvinyl chloride film is avoided, which would otherwise lead to malfunctions would that for the metal of the apparatus at the present of acids would have dire consequences. In addition, covering with foils is very difficult to carry out, when complex parts, small diameter pipes, etc. need to be lined.

We know already different \ ⁷ 'experience of applying rigid polyvinyl chloride on metals. It has been proposed to join a rigid film to a plasticized film by melting and then to attach the latter to the metal with a binder. Recently, polyvinyl chloride films on steel and aluminum, which are made of plasticized polyvinyl chloride of a special composition, have been put on the market. These coatings exhibit excellent mechanical properties but, as stated, require special compositions and equipment for their manufacture.

It is also known to improve the adhesive strength of polyvinyl chloride on metal organic Apply adhesive layers that provide an intermediate layer between the metal and the polyvinyl chloride coating form. Such adhesive layers, however, do not yet show such adhesive strength as they are for must demand high loads.

It has now been found that the adhesion of plasticized polyvinyl chloride to metals Can further improve greatly if a solution of a polymer of vinylpyridine, which is also substituted can be applied to form an adhesive layer

the adhesion of plasticizer-containing

Polyvinyl chloride coatings on metals through an organic adhesive layer

Applicant:

MONTECATINI Soc. Gene.

per rindustria Mineraria e Chimica,

Milan (Italy)

Representative:

Dipl.-Ing. Dipl.-Chem. Dr. phil. Dr. techn. J. Reitstötter, Patent attorney, Munich 15, Haydnstr. 5

Claimed priority:
Italy September 14, 1955

Riccardo Forquet, Milan (Italy),
has been named as the inventor

which is then coated with polyvinyl chloride in the form of a solution, paste or film.

A volatile solvent is used to prepare a solution of the polyvinylpyridine after applying the solution to the metal by heating it is evaporated before the polyvinyl chloride coating is applied to the adhesive layer. The polyvinyl chloride is then allowed to gel.

The solutions can be applied very simply in a known manner, expediently by spraying on from a spray gun be applied to the documents. Before the metal is coated with the adhesive layer, it is easy to clean.

If one proceeds in the manner just described, then one obtains a coating with all the advantages the chemical resistance of polyvinyl chloride, which adheres perfectly to the metal and can practically no longer be replaced by this.

The adhesive properties of polyvinylpyridine were known per se, but had not yet been found been that with their help perfect, solid connections between a metal and a synthetic resin how polyvinyl chloride can be achieved and that in this way very strong

909 728/332

Polyvinyl chloride coatings obtained from normal mixtures or plastisols on metals.

It is of course also possible to use polyvinylpyridines made from plasticized polyvinyl chloride to connect manufactured foils to the metal by simply gluing at room temperature.

An excellent binder, a polymer is suitable from 2-vinylpyridine, but also polymers from substituted vinylpyridines, such as 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine, etc. are usable.

The amount of polyvinylpyridine solution required to achieve the adhesive effect is very small and in practice corresponds to the amount required to coat the metal surface with a thin one. Veil is necessary. It is possible, for example, to coat ^{a metal surface of 1 m 2} with 50 ecm of an ICW polyvinylpyridine solution in carbon tetrachloride. Such solutions are generally used in concentrations of 5 to 20%. As far as the thickness of the polyvinyl chloride coatings on metals is concerned, layers with a thickness of 0.001 to 2 mm are obtained when foils are applied, while layers of up to a maximum of 2 mm can be achieved with the direct application of polyvinyl chloride mixtures.

example 1

A 5 ° / o acetone solution of polyvinyl is sprayed in a well cleaned surface of steel, and the solvent in an oven at 10O ⁰ C evaporated. The surface is then sprayed with a paste composed of 60 parts by weight of polyvinyl chloride, 40 parts of dioctyl phthalate, 2 parts of cadmium stearate and. 5 parts of barium sulfate. The piece of metal is then placed in an oven at 150 ° C. for 45 minutes.

In this way, the resin adheres perfectly to the metal. From. one in the same way, however, omitting the treatment with the polyvinylpyridine solution, the metal piece coated will come off removes the vinyl resin with the utmost ease, revealing the complete lack of adhesion between Metal and resin.

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Example 2

The inner surface of a. The metal container is covered by means of spray gun with a 20 ^c / aigen acetone solution of polyvinyl pyridine, whereupon and the treated with polyvinylpyridine surface in turn pulls the solvent at 8O ⁰ C evaporating a spray gun with a 10 ° / o solution of polyvinyl chloride in cyclohexanone; the vessel is then heated to 170 ° C. for 30 minutes. The resin applied in this way adheres perfectly to the walls of the vessel.

Example 3

An aluminum plate is coated with an 8% polyvinylpyridine solution in carbon tetrachloride using a spray gun; the solvent is evaporated in an oven at 100 ⁰ C, followed by spraying a paste to the pretreated surface, which consists of 60 parts by weight of polyvinyl chloride, 40 parts of dioctyl, 2 parts of lead silicate, 5 parts of barium sulfate and 0.1 parts of heat-resistant blue pigment, ^{whereupon it is heated to 185 °} C. for 25 minutes to gel the resin, after which the resin adheres completely to the metal.

Example 4

A well-cleaned steel plate is sprayed with a 9% solution of poly-5-ethyl-2-vinylpyridine in carbon tetrachloride; to the thus treated surface to wear by means of a roller has a film of 5 thousandths of a millimeter thickness, which äthylhexylphthalat 2-Di-by lOminutiges calendering a mixture of 60 parts of polyvinyl chloride, 40 parts and 2 parts of Sb ₂ O was obtained at 170 ⁰ C for ₃ .

The metal plate covered with the polyvinyl chloride film is left at room temperature for 24 hours left. After this time the film is found to be perfectly adherent and has good flame retardancy properties owns.

Example 5

A 12% solution of poly-5-ethyl-2-vinylpyridine in dimethylformamide is cleaned well Aluminum plate sprayed on; the plate is then heated to 100 ° C. for 3 minutes, whereupon a film of 1 mm thickness is applied, which by calendering a mixture of 65 parts for 15 minutes Polyvinyl chloride, 35 parts of tricresyl phosphate, 2 parts of lead stearate and 1 part of titanium dioxide were produced at 180 ° C became.

The metal plate covered with the polyvinyl chloride film is left for 30 hours at room temperature left.

After this time, the metal plate has a completely adhesive, opaque, white coating.

By adding suitable dyes to the vinyl resin mixtures, it is possible to produce colored coatings to obtain; The colorants that can be used for this purpose include the following: carbon black, leg black, titanium dioxide, calcium carbonate, calcium sulfate, Barium sulfate, clay, chrome yellow, chrome oxide green, yellow iron oxide, red iron oxide, brown iron oxide, Cadmium red, cadmium orange, cadmium yellow, ultramarine blue, molybdenum yellow, benzidine yellow, pyrazolone orange, Pyrazolone red, anisidine orange, phthalocyanine green, phthalocyanine blue, indanthrene blue, Indigo brown and indigo red. Special effects can be achieved on the coatings if they are in the heat treated with suitably engraved rollers.

Example 6

Well-cleaned steel plates were coated with a 20% acetone polyvinylpyridine solution; the solvent was ^{evaporated at 100 0} C, whereupon the plate was sprayed with a paste, which consisted of 65 parts of polyvinyl chloride, 35 parts of trikesyl phosphate, 2 parts of lead stearate and 0.2 parts of a dye, each time a different dye from the above Application.

All treated panels were placed for 40 minutes in an oven at 15O ⁰ C. Different colored plates were obtained in this way.

Example 7

Well-cleaned aluminum plates were made with a 12% solution of polyvinylpyridine in carbon tetrachloride sprayed. A mixture of 65 parts was produced by calendering at 170 ° C. for 10 minutes Polyvinyl chloride, 35 parts of di-2-ethyl-hexyl phthalate, 1 part cadmium stearate and 0.2 part of a dye make films 0.6 mm thick, each time

a different dye was used; these films were applied to the pretreated using a roller Plates applied. The same colorants used in the previous example were used. the various metal plates coated with the polyvinyl chloride sheets were exposed for 20 hours kept at room temperature, with completely adhesive and differently colored coatings received which at most from the action of rollers with a suitably engraved surface at 140 to 170 ° C to achieve special relief effects can be.

Example 8

A mixture of 65 parts of polyvinyl chloride, 5 parts of kaolin, 35 parts of di- (2-ethyl-hexyl) phthalate and 0.3 parts chrome yellow is heated for 12 minutes at 105 ⁰ C. The mass obtained in this way is cooled and mechanically divided into fine particles. An identical mixture, which, however, contains chromium oxide green instead of chrome yellow, is treated in the same way. The two colored resins are mixed after crushing and sprayed in a thin layer onto an aluminum plate which had previously been sprayed with a layer of a 5% polyvinylpyridine solution in carbon tetrachloride.

The plate is gradually heated to 175 ° C. and at this temperature for half an hour held for complete gelation of the resin covering the plate. You get one that way adhesive cover with characteristic color effect.

Example 9

A 15% solution of polyvinyl pyridine in carbon tetrachloride is sprayed in a well-cleaned steel plate, followed by evaporating the solvent at 100 ⁰ C and a mixture of parts of polyvinyl chloride, 40 parts of di- (2-ethylhexyl) phthalate and 1 part of lead stearate as a thin Layer applies. A thin layer of tiny glass beads with an average diameter of 15 microns is applied to this and the plate covered in this way is then heated to gel the resin. A coating is obtained which adheres perfectly to the metal surface and which, when a ray of light falls on it in the dark, itself glows brightly.

Claims (3)

PATENT CLAIMS: 1. Process for improving the adhesion of plasticized polyvinyl chloride coatings on metals by an organic adhesive layer, characterized in that a solution of a Polymer of optionally substituted vinyl pyridine applied to form the adhesive layer which is then coated with polyvinyl chloride in the form of a solution, paste or film will. 2. The method according to claim 1, characterized in that the solvent of the polymer, which is applied to form the adhesive layer, evaporated before the application of the polyvinyl chloride will. 3. Process according to claims 1 and 2, characterized in that a polymer of 2-vinyl pyridine is used. Considered publications:
Swiss Patent No. 210 205;
British Patent No. 695,790;
U.S. Patent No. 2,047,957. <© 909 728.7332 1.60