Patent GB-675507-A (GB)
Title: Improvements in or relating to the production of uniform adherent metal coatings on metal surfaces and to oleaginous waxy compositions which aid in their production
IPC: C23C2/08
Filed: 1948-03-19
Abstract: Oleaginous waxy compositions which aid in the production of uniform adherent coatings of lead, tin or lead-tin mixtures on metal surfaces have an acid number of 3-15 and comprise a non-aromatic waxy hydrocarbon and a hydrogenated and split fatty oil product.  The hydrogenated and split fatty oil product is one obtained by subjecting a fatty oil to one or more hydrogenating and splitting steps which may be carried out in any sequence or simultaneously, and if desired, carrying out one or more distillation steps before, after or between the hydrogenating and splitting steps and removing, if desired, either the residuum or distillate fractions.  A list of animal, vegetable, marine and fish oils is given and the hydrogenated and split fatty oil product may be obtained by the hydrogenation and splitting of such oils, their distillate and residuum fractions and/or their mixtures.  The non-aromatic waxy hydrocarbon may be of petroleum origin or may be prepared by polymerization of olefinic material, by the Fischer-Tropsch process or by dehydration of long chain aliphatic alcohols.  The compositions may also contain minor proportions of other types of natural and synthetic waxes or derivatives thereof such as the corresponding oxidation products; thus the compositions may contain woolfat, lanoline, beeswax, insect wax, montan wax or oxidized paraffin wax.  Other optional ingredients of the compositions are antioxidants and oleophilic oxygen-containing polar organic compounds having draining promoting properties.  A list of amines suitable as antioxidants is given.  The oleophilic oxygen-containing compounds are also listed, examples of the following types being given:- organic silicon compounds, oxidized hydrocarbons, maleic anhydride condensation products with other organic substances, acetone condensation products, phenol-aldehyde condensation products, organic acids, organic phosphates, amides and metal salts of organic compounds.  In the metal coating process, the surface of the metal article to be coated may be cleaned and pickled and the cleaned article passed through a molten flux bath, on through a bath of molten tin, molten lead or a molten mixture of lead and tin, and finally through the oleaginous waxy composition maintained at an elevated temperature.  In order to maintain the acid number of the oleaginous waxy composition at 3-15, a replenishing agent may be added during use.  The replenishing agent consists of a mixture of a non-aromatic waxy hydrocarbon and a hydrogenated and split fatty oil product in a ratio by weight within the range of 1 : 3 to 3 : 1.  In the examples, oleaginous waxy compositions are described having an acid number of 15 and consisting of (a) hydrogenated and split fish oil distillates together with a non-aromatic hydrocarbon wax obtained from a mineral oil residuum, a non-aromatic Pennsylvania cylinder stock slop wax (with or without phenyl a -naphthylamine) or a C36 liquid dimer obtained by dehydrating C18 alcohols ("Stenol") or (b) hydrogenated and split fish oil residuum together with a non-aromatic hydrocarbon wax obtained from a mineral oil residuum.  For comparison purposes, compositions are described consisting of mineral oil and (i) palm oil, (ii) hydrogenated and split fish oil residuum with or without phenyl a -naphthylamine or (iii) hydrogenated and split fish oil distillates.  Specifications 586,839, 665,447 and 665,448 are referred to.ALSO:Oleaginous waxy compositions which aid in the production of uniform adherent coatings of lead, tin or lead-tin mixtures on metal surfaces have an acid number 3-15 and comprise a non-aromatic waxy hydrocarbon and a hydrogenated and split fatty oil product (see Group III).  In the metal coating process, the surface of the metal article to be coated may be cleaned and pickled and the cleaned article passed through a molten flux bath, or through a bath of molten tin, molten lead or a molten mixture of lead and tin, and finally through the oleaginous waxy composition maintained at an elevated temperature.  In order to maintain the acid number of the oleaginous waxy composition at 3-15, a replenishing agent may be added during use.  The replenishing agent consists of a mixture of a non-aromatic waxy hydrocarbon and a hydrogenated and split fatty oil product in a ratio by weight within the range of 1:3 to 3:1.  In the examples, (a) pickled sheets of black plate, stored in 0.5 per cent HCl, were dipped in a flux consisting of a molten mixture of zinc chloride and ammonium chloride and tinned at 550 DEG F.  The tinning pot surface was covered with flux.  Immediately after withdrawal from the tinning pot, the sheets were transferred to a finishing pot containing tin at 545 DEG F and a superimposed layer of the oleaginous waxy composition.  Here the metal sheets were immersed in the tin and then drained in the superimposed layer. In a modification (b), the tinned sheets, after being withdrawn from a tinning pot at 535 DEG F and before being transferred to a finishing pot at 460-475 DEG F were introduced into a second tinning pot at 475 DEG F containing molten tin with just sufficient tallow to form a ring covering the bath edges.  In a second modification (c), the flux was contained in a separate pot in which no tin was present, while the tinning pot surface was covered with the oleaginous waxy composition at 475-490 DEG F and no finishing pot was employed.  The oleaginous waxy compositions employed in the examples consist of (i) hydrogenated and split fish oil distillates together with a non-aromatic hydrocarbon wax obtained from a mineral oil residuum, a non-aromatic Pennsylvania cylinder stock slop wax (with or without phenyl-a -naphthylamine) or a C36 liquid dimer obtained by dehydrating C18 alcohols ("Stenol") or (ii) hydrogenated and split fish oil residuum together with a non-aromatic hydrocarbon wax obtained from a mineral oil residuum.  For comparison purposes, the tinning processes of the examples are carried out using, instead of the oleaginous waxy compositions, a mixture of mineral oil with (A) palm oil, (B) hydrogenated and split fish oil residuum with or without phenyl-a -naphthylamine or (C) hydrogenated and split fish oil distillate.  Specifications 586,839, [Group III], 665,447 and 665,448 are referred to.