FR2479844A1 - Water-insol. alkyl-sulphonamido-carboxylate - as anticorrosive agent for metals, esp. automobile bodies and chassis - Google Patents

Abstract

An anti-corrosive agent for (non)ferrous metals consists of a water-insol., opt. base-reacted, cpd. of formula R'-SO2-(N(R")-R"'-CO-OZ (I) where R' and R" are (un)branched aliphatic chains, or (hetero)- cyclic hydrocarbons chains; R" is defined as R' and R"', or may be H; and the hydrocarbon chains may have at least 1 substit., and at least 1 atom other than C in the chain; and Z is H, a metal, an alkali(ne earth) metal, a metalloid, a radical formed by action of a mineral or organic base on the acid form of I, or may be a gp. defined as is R'. When Z is a bivalent element or radical, I has the formula (II). In partic., Z is an alkaline earth and R' is a not less than 10C linear aliphatic radical. I is esp. used to protect automobile bodies and chassis. Protection is given for a longer time than with known anti- corrosives. Corrosion by acids, bases and oxidn. is prevented.

Description

 The subject of the present invention is an anticorrosion agent for ferrous and non-ferrous metals, which can be used in particular but not exclusively in the protection of bodies and chassis of motor vehicles.

Shallow anti-corrosion agents have been known, used in particular to protect motor vehicle bodies in admixture with the paint coating them.

 However, the object of the invention is to produce anticorrosion agents, capable of providing protection against corrosion of ferrous or non-ferrous metals for a period considerably greater than the duration of protection provided by known anticorrosion agents, such as by example commercial calcium alkyl sulfonate.

dans laquelle
- R1 est une chaîne hydrocarbonée aliphatique linéaire ou ramifiée, ou une chaîne hydrocarbonée cyclique ou hétérocyclique,
- R2 peut être un hydrogène ou une chaîne hydrocarbonée aliphatique linéaire ou ramifiée ou une chaîne hydrocarbonée cyclique ou hétérocyclique,
- R est une chaîne hydrocarbonée aliphatique
3 linéaire ou ramifiée ou une chaîne hydrocarbonée cyclique ou hétérocyclique,
- Z est l'un des composants suivants : hydrogène, métal, métal alcalin, métal alcalino-terreux, métallode, radical résultant de la réaction d'une base minérale ou organique sur la forme acide desdits composées, chaîne hydrocarbonée aliphatique linéaire ou ramifiée ou une chaîne hydrocarbonée cyclique ou hétérocyclique,
- ces différentes chaînes hydrocarbonées aliphatiques linéaires ou ramifié as ou cycliques ou hétérocycliques pouvant posséder au moins un atome d'hydrogène substitué et au moins un atome autre que le carbone, intercalé dans la chaîne hydrocarbonée.According to the invention, the anticorrosion agent of ferrous and non-ferrous metals, is characterized by a basified or non-basified form, insoluble in water, of any of the compounds defined by the following general formula

in which
- R1 is a linear or branched aliphatic hydrocarbon chain, or a cyclic or heterocyclic hydrocarbon chain,
R2 can be a hydrogen or a linear or branched aliphatic hydrocarbon chain or a cyclic or heterocyclic hydrocarbon chain,
- R is an aliphatic hydrocarbon chain
3 linear or branched or a cyclic or heterocyclic hydrocarbon chain,
Z is one of the following components: hydrogen, metal, alkali metal, alkaline earth metal, metallode, radical resulting from the reaction of a mineral or organic base with the acid form of said compounds, linear or branched aliphatic hydrocarbon chain or a cyclic or heterocyclic hydrocarbon chain,
- These different linear or branched as or cyclic or heterocyclic aliphatic hydrocarbon chains which may have at least one substituted hydrogen atom and at least one atom other than carbon, intercalated in the hydrocarbon chain.

This family of products is known in certain applications such as detergents, soaps, wetting agents, etc.

but not as anti-corrosion agents in a form insoluble in water.

 In fact, it is important that the anti-corrosion agents mixed with the paint intended to coat the vehicle bodies cannot dissolve in the atmospheric precipitation precipitation and be entrained by it.

 It will thus be possible for example to use zinc, calcium or magnesium salts, etc., of compounds according to the general formula above.

Corrosion protection can be temporary, or long-term protection, both in the atmospheric environment and in a liquid.

According to one embodiment of the anti-corrosion agent according to the invention, in the case where Z is a bivalent metal, a bivalent alkali metal, a bivalent alkaline earth metal, a bivalent metalloid or a bivalent radical resulting from the reaction of a mineral or organic base on the acid form of these compounds, the general formula of the latter is as follows

In each of the possible formulas of the anticorrosion agent targeted by the invention, the different chains R1, R2, R3, aliphatic, linear or branched or cyclic or heterocyclic, may have, as indicated previously, one or more substituted hydrogen atoms and may also have atoms other than carbon, intercalated in these hydrocarbon chains.

 This anticorrosion agent can be used in dilution in a solvent, in the ratios 99.9 to 0.1 or 0.1 to 99.9.

 In another possible mode of use provided for by the invention, the anti-corrosion agent is used combined in the ratios 99.9 to 0.1 or 0.1 to 99.9 with at least one diluent or thickener, having itself -even possibly anti-corrosion properties and which can be either synthetic organic products or natural organic products, or synthetic mineral products, or natural mineral products which may or may not synergize with the compounds defined by the general formulas above .

 In one possible embodiment of the anticorrosion agent, the chain R1 has at least ten carbons.

Finally, the anticorrosion agent according to the invention can be used combined with oxidized or non-oxidized petrolatum, microcrystalline waxes or non-microcrystalline waxes, asphalts, solvents, imidazolines and their derivatives, oxazoles and their derivatives.

 As an example of a natural mineral product that can be used, mention may be made of calcium carbonate.

 Systematic tests carried out with anti-corrosion products corresponding to the above formulas have shown that the water-insoluble compounds all have remarkable anti-corrosion properties, both against acids and bases and against corrosion by oxidation. Certain soluble compounds in which Z is sodium, potassium or different amines, are known and used for their anticorrosion power in aqueous solutions. But precisely the fact that they are soluble in water makes them unsuitable for use as anticorrosive agents for vehicle bodies.

 It is therefore essential that the anti-corrosion agents used for this purpose are absolutely insoluble in water, so as not to be entrained by atmospheric precipitation on the vehicle.

 It has been found that the compounds corresponding to the general formulas above, in which Z is an alkaline earth metal, have greater anticorrosion properties than the other compounds which are insoluble in water.

 during various tests carried out comparatively as will be described below, it could be determined that the water-insoluble compounds corresponding to the general formulas above, in which R1 is a linear aliphatic hydrocarbon chain whose number of carbons is at least ten, give better results than the water-insoluble compounds corresponding to these general formulas, in which R1 is a linear aliphatic hydrocarbon chain whose number of carbons is less than ten, or a branched aliphatic hydrocarbon chain, or a cyclic or heterocyclic hydrocarbon chain.

 We will now give some examples of anti-corrosion tests carried out with agents meeting the characteristics mentioned above.

Corrosion tests in a humid cabinet at 250C
Compound nO 1: zinc alkylsulfamido-carboxylate,
Compound No. 2: calcium alkylsulfamido-carboxylate,
Compound nO 3: magnesium alkylsulfamido-carboxylate,
Control: commercial calcium alkylsulfonate.

 the tests were carried out on sanded and degreased iron plates, the protective films having been applied to a thickness of 100 microns. the tests were stopped after 4500 hours.

The results were as follows
Compound nO 1: start of corrosion after 3000 hours.

 Compound NO 2: no corrosion after 4500 hours.

 Compound NO 3: no corrosion after 4500 hours.

 Control: beginning of corrosion after 2450 hours.

Anti-corrosion tests with salt spray
the tests were carried out starting from the compounds -nO 1, nO 2, nO 3 and the control of the anticorrosion tests in wet cabinet above.

 The four compounds were formulated at 40% by weight in an equal amount for the four compounds of a mixture of oxidized petrolatum, microcrystalline wax, asphalt and white spirit with less than 5% of aromatic compounds, so as to obtain a liquid passing to the Ford nO 4 cut in 60 seconds.

the four final formulations were applied on sanded iron plates and degreased to a thickness of 250 microns. the four protected plates thus obtained were dried in a free atmosphere for fifteen days before the tests. the salt spray corrosion tests were conducted over a continuous period of 1,500 hours.

 After 1,500 hours, compound No. 1 exhibits a peak in full plate corrosion, compounds No. 2 and No. 3 exhibit no corrosion, the control has several points of corrosion in full plate.

Testing of anticorrosion primary paints
We know that anti-corrosion primer paints are very often lead lead, zinc powder or zinc chromate paints.

 Zinc chromate primer paints are commonly used for the anticorrosion protection of ferrous and non-ferrous metals.

 Effectively in the presence of moisture, the zinc chromate slightly soluble in water releases corrosion-inhibiting ions.

 However, this solubility of the zinc chromate laughed that the tests carried out on the primary paints containing this inhibitor give relatively poor results to salt spray, all the more since these paints have a high porosity.

 The tests were carried out with a commercial paint, the zinc chromate concentration of which has not been determined, and containing glycerophthalic resins as drier.

 Product no. 1: commercial zinc chromate paint based on glycerphthalic resin.

 Product No. 2: Product No. 1 supplemented with calcium alkyl sulfamido-carboxylate in an amount of 3% by weight.

 Product No. 3: Product No. 1 supplemented with calcium alkyl sulfamido-carboxylate in an amount of 6% by weight.

 The products nO 1, nO 2 and n0 3 were applied to a thickness of 150 microns on sanded and degreased iron plates. These plates were dried in a free atmosphere for 8 days.

Salt spray test results
Product 1: point corrosion from 125 hours.

 Product # 2: spot corrosion from 175 hours.

 Product nO 3: spot corrosion from 240 hours.

Similar results can be obtained with the other insoluble salts, for example magnesium, zinc.

The various compounds of the family defined by the preceding general formulas can be used either singly or as a mixture, for example on the basis of two or more compounds.

For motor vehicle bodies, this or these compounds are used in admixture with primary paints.

 For hollow bodies, the anticorrosion compounds according to the invention can be combined with an appropriate component taken from, for example, pitches, waxes, petrolatums.

 For rocker panels of motor vehicles, calcium alkyl sulphonate is currently used; the anticorrosion agent according to the invention capable of being applied to the rocker panels must be sufficiently viscous to pass to the Ford No. 4 cut at least in approximately 200 seconds. To do this, the selected anticorrosion agent is mixed with thickeners, plasticizers, organic or mineral, natural or synthetic (petrolatums for example), or other corrosion inhibitors, such as imidazolines and oxazoles.

 The invention is not limited to the embodiments described above and can include numerous variant embodiments. Thus, it is obvious that one can use the anticorrosive agent with a single diluting or thickening product, falling into the various categories mentioned above (synthetic organic product, natural organic products, etc.).

The anticorrosion agent according to the invention finds a particularly interesting field of application in the protection of motor vehicle bodies.

Claims (6)

 1 - Anti-corrosion agent for ferrous and non-ferrous metals, characterized in that it consists of a basified or non-basified form, insoluble in water, of any of the compounds defined by the following general formula

in which - R1 is a linear or branched aliphatic hydrocarbon chain, or a cyclic or heterocyclic hydrocarbon chain,  R2 can be a hydrogen or a linear or branched aliphatic hydrocarbon chain or a cyclic or heterocyclic hydrocarbon chain,  - R3 is a linear or branched aliphatic hydrocarbon chain or a cyclic or heterocyclic hydrocarbon chain, Z is one of the following components: hydrogen, metal, alkali metal, alkaline earth metal, metalloid, radical resulting from the reaction of a mineral or organic base with the acid form of said compounds, linear or branched aliphatic hydrocarbon chain or a cyclic or heterocyclic hydrocarbon chain,  these different linear or branched or cyclic or heteroeyelic aliphatic hydrocarbon chains which may have at least one substituted hydrogen atom and at least one atom other than carbon, intercalated in the hydrocarbon chain4 2 - anticorrosion agent according to claim 1, characterized in that, in the case where Z is a bivalent metal, a bivalent alkali metal, a bivalent alkaline earth metal, a bivalent metalloid or a bivalent radical resulting from the reaction of a mineral base or organic on the acid form of these compounds, the general formula of the latter is as follows

3 - anticorrosion agent according to one of claims 1 and 2, characterized in that it is diluted in a solvent in the ratios 99.9 to 0.1 or 0.1 to 99.9. 4 - Anticorrosive agent according to claim 3, characterized in that it is used as an alloy in the ratios 99.9 to 0.1 or 0.1 to 99.9 to at least one diluting or thickening product, itself possibly having anticorrosion properties which may be either synthetic organic products or natural organic products, or synthetic mineral products, or natural mineral products, whether or not mixed, synergistically or not, with the compounds according to claim 1 or 2.  5 - anticorrosion agent according to one of claims 1 to 4, characterized in that the chain R1 has at least 10 carbons.  6 - anticorrosive agent according to any one of claims 1 to 5, characterized in that it is used in combination with oxidized or non-oxidized petroleum jellies, with microcrystalline waxes or with non-microcrystalline waxes, with asphalts, with solvents, imidazolines and their derivatives, oxasoles and their derivatives.