EP3461931B1 - Compositions of vapour phase corrosion inhibitors and their use and method for preparing them - Google Patents

Description

Background of the Invention

The present invention relates to combinations of substances as vapor phase corrosion inhibitors (vaporization or sublimation-capable corrosion inhibitors, vapor phase corrosion inhibitors VpCI, volatile corrosion inhibitors, VCI) and methods of their application for protecting common consumer metals, such as iron, chromium, nickel, aluminum, copper and the like Alloys as well as galvanized steels against corrosion in moist air climates.

For several decades, compounds identified as corrosion inhibitors, which also tend to evaporate or sublimate under normal conditions and can therefore reach metal surfaces to be protected via the gas phase, have been used for temporary corrosion protection of metal objects in closed rooms, e.g. used in packaging, control cabinets or showcases. Protecting metal parts from corrosion during storage and transport is the clean alternative to temporary corrosion protection with oils, greases or waxes.

All measures of the temporary corrosion protection of metals against the influence of air-saturated aqueous media or condensed water films are known to have the aim of preserving the primary oxide layer (POL), which is always present on consumer metals after first contact with the atmosphere, before chemical and mechanical degradation (cf. eg: E. Kunze (ed.), Corrosion and Corrosion Protection, Volume 3, Wiley-VCH, Berlin, New York 2001, pp. 1679-1756 ). In order to cope with the corrosion inhibitors, which preferably act via the vapor phase, it must be taken into account that the customary metals and the POL present on their surfaces each have different chemical properties. Vapor phase corrosion inhibitors are therefore basically based on the type of metal to be protected to select (see e.g.: US 4,374,174 , US 6,464,899 , US 6,752,934 B2 , US 7,824,482 B2 and US 8,906,267 B2 ).

For objects and constructions that were made from different metals and may also be in different processing states (rough, ground, polished, etc.), combinations of different corrosion inhibitors are also required to ensure that the metals and surface conditions in question are contained in one and the same container or a common packaging to ensure reliable temporary corrosion protection. Since such mixed metal objects and components are technically most frequently represented according to the available experience, the discovery of suitable material combinations of corrosion inhibitors acting via the vapor phase is still of increasing importance.

The use of such combinations of volatile corrosion inhibitors (VpCI / VCI) in practice should, above all, be possible after the already established applications, but coordinated with the different sensitivity of the metals to be protected and surface conditions in air of different rel. Moisture and composition as well as the compatibility of the individual components with each other.

In order to achieve reliable corrosion protection for metallic components within containers and packaging, the walls of which are permeable to air containing water vapor (paper, plastic film, etc.), VpCI / VCI must be used to ensure that the active ingredients generally get out of the respective case sufficiently quickly Depot are released by evaporation and / or sublimation, reach the metal surfaces to be protected by diffusion and convection within the closed packaging and form an adsorption film there before water from moist air can condense at the same place.

The time known as the so-called conditioning or incubation time, during which the conditions for VCI corrosion protection arise after the container / packaging has been closed, may be more susceptible to corrosion than average Metal surfaces are naturally not too large, since otherwise the corrosion process is started before the VCI molecules come close to the metal surface.

Depending on the type of metals to be protected and the surface conditions present, not only is a suitable combination of VpCI / VCI components to be used, but they are also to be applied in such a way that the so-called build-up phase required to develop their effect is adapted to the relevant requirements.

Solids that tend to sublimate under normal conditions are known to adjust their evaporation equilibrium with the gas phase the easier, the larger their specific surface area is. Providing such corrosion inhibitors in powder form with the smallest possible particle size can therefore be regarded as a basic requirement for setting the shortest possible construction phase. VpCI / VCI in the form of finely dispersed powder, packaged in bags made of a material which is permeable to the vaporous active substances (for example paper bags, porous polymer film, perforated capsule), have therefore been commercially available for a long time. Exposing them inside a closed package next to the metal parts to be protected is the simplest form of practical application of VpCI / VCI (see e.g.: E. Vuorinen, E. Kalman, W. Focke, Introduction to vapor phase corrosion inhibitors in metal packaging, Surface Engng. 29 (2004) 281 pp ., US 4,973,448 , US 5,393,457 , US 6,752,934 B2 , US 8,906,267 B2 , US 9,435,037 and EP 1 219 727 A2 ). The build-up phases that can be achieved in this way can also be regulated by the permeability of the walls of such depots. If mixtures of different substances are to be used instead of individual corrosion inhibitors, then it must also be ensured that they neither react chemically with one another nor lead to the formation of agglomerates, since this prevents both their emission from the depot and their required chemisorption on the metal surfaces to be protected or at least would be affected more.

Today, the VpCI / VCI are usually already integrated in modern packaging materials for temporary corrosion protection, so that their technical application can be carried out simply and automatically. Papers, cardboards, foams or textile nonwoven materials with a VCI-containing coating are just as common as polymeric carrier materials into which the relevant VCI active ingredients have been incorporated in such a way that their emission from them remains possible. So z. B. in the patents US 3,836,077 , US 3,967,926 , US 4,124,549 , US 4,290,912 , US 5,209,869 , US 5,332,525 , US 5,393,457 , US 6,752,934 B2 , US 7,824,482 , US 8,906,267 B2 , JP 4,124,549 , EP 0.639.657 and EP 1,219,727 Various variants have been proposed, always with the aim of placing the VpCI / VCI in a depot, such as in capsules, coatings or gas-permeable plastic films, in such a way that a product results from which the VCI components can continuously evaporate or sublime. To achieve this with combinations of several substances and to set a physically roughly similar behavior for each component with regard to migration in the depot and emission from it is, of course, complicated and obviously explains that in many applications with the previously known substance combinations, especially for mixed metal objects and - Components only rarely achieve optimal VCI corrosion protection properties. In individual cases, for example, different particle sizes of the components of a combination of substances can cause defects in corrosion protection if, for example, the structure-related pores of the walls of the active substance depot are not large enough to guarantee similar conditions for permeation and sublimation of the individual molecules or molecular associates for all components of the active substance mixture.

Experience has shown that incorporating the VpCI / VCI into a coating agent makes it relatively easy to produce coatings on flat packaging materials (paper, cardboard, foam, textile nonwoven material, etc.) from which the respective VpCI / VCI are released at emission rates that are appropriate for the VCI corrosion protection guarantees comparatively short assembly phases. In the first instance, this requires the selection of a suitable coating agent that finely disperses the material combination entered in powder form and with a sufficiently high degree of filling, cross-linked on the respective substrate to form a well-adhering, porous layer, from which the VpCI / VCI in question can then sublime with little resistance . With the amount of VpCI / VCI coating agent applied, it is also possible to adapt the VpCI / VCI depot to the requirements of the shortest possible construction phases.

To produce VpCI / VCI-containing packaging means by dispersing the active ingredients in a suitable coating agent and applying them to a flat carrier material have been practiced for a long time. Processes of this type with various active ingredients and coating agents are described, for example, in JP 61.227.188 , JP 62.063.686 , JP 63.028.888 , JP 63.183.182 , JP 63.210.285 , US 5,958,115 , US 8,906,267 B2 and US 9,518,328 B1 described.

The incorporation of VpCI / VCI in polymeric carrier materials, preferably in polyolefins (PO), such as polyethylene (PE) and polypropylene (PP), and the provision of VpCI / VCI emitting films and other PO products (granules, trays, etc.), as they e.g. B. is proposed in US 4,124,549 , US 4,290,912 , US 5,139,700 , US 6,464,899 B1 , US 6,752,934 B2 , US 6,787,065 B1 , US 7,824,482 , EP 1 218 567 A1 and EP 1641960 B1 , experience shows that it is practiced to a particularly high degree today, if only because these products can be used advantageously for the automation of packaging processes.

However, these polymer-based VpCI / VCI products generally have the disadvantage that the VpCI / VCI incorporated in the course of extrusion via the polymer melt are relatively firmly enclosed in powder form or in coatings, in contrast to the VpCI / VCI depots described above and their emission from it is only comparatively difficult. In VpCI / VCI films, which are usually used today with layer thicknesses d in the range of 60 µm ≤ d ≤ 150 µm, the concentration of active ingredients, which is not nearly as high as in VpCI / VCI coatings, can be accommodated. In addition, losses of VpCI / VCI components that are difficult to control occur usually during the extrusion of the relevant masterbatches and foils due to the thermal load that occurs. Experience has shown that none of the previously known VpCI / VCI material combinations could be used to provide foils that are suitable for VCI corrosion protection of above-average corrosion-prone metal surfaces, if only for the reasons mentioned, it was not possible to set the required relatively short assembly phases. The VpCI / VCI foils which are commercially available today are therefore mainly used as mass-produced articles which are technologically easy to apply, without being able to meet higher requirements for their VCI corrosion protection properties.

In order to improve this situation and to better profile packaging with polymer films with regard to the introduced VpCI / VCI system, several proposals have become known. All measures to allow the emission of the VpCl / VCl components integrated in polymer films in one direction only seem to be obvious, oriented towards the metal part to be protected in the packaging, and to equip the opposite side as a barrier.

For example, in US 5,393,457 A1 , US 7,763,213 B2 and US 8,881,904 B2 proposed to coat the packaging primarily produced with a VpCI / VCI-containing film around the metal part to be protected with an additional barrier film. In the US 5,137,700 on the other hand, it is intended to laminate the outside of the VpCI / VCI film with a metal or plastic layer acting as a barrier before use as packaging material and to specify the film equipped with the VpCI / VCI components as the inside when packaging the metal part to be protected. The proposal according to US 8,881,904 B2 According to our own experience, producing the VpCI / VCI film in multiple layers from the start by coextrusion and not dosing a VpCI / VCI masterbatch in the layer positioned on the outside does not lead to this outer layer of the film subsequently acting as a barrier against the permeation of the vaporous VpCI / VCI components acts. Instead, the emission of the VpCI / VCI components from the inner layer into the gas space of the packaging usually deteriorates because the degradation of the concentration gradient required for this by migration of the active substances into the outer layer, which is initially free of active substances, starts already during storage of the coextrusion film on a roll and a reduction of the VCI effect.

Since it has so far not been possible to accelerate the emission of the relevant VpCI / VCI components into the interior of the closed packaging with the use of an additional barrier film or by equipping the outside of a VpCI / VCI-containing film as a diffusion barrier, further measures were proposed, in order to shorten the so-called assembly phase for the integrated VpCI / VCI system in a film packaging in such a way that improved VCI corrosion protection properties result. One way in this direction is, for example, coating the inside of a polymer film with a gel containing the VpCI / VCI components, fixed under a gas-permeable inner film Tyvek® 1059 (DuPont) (cf. US 7,763,213 B2 ), which should also make it possible to specify significantly higher proportions of the VpCI / VCI components than can be achieved by direct integration into a polyolefin film by means of extrusion.

Another approximately similar way consists in introducing individual or several VpCl / VCI components into a suitable adhesive in order to subsequently coat the inside of polymer films as required (see, for example: EP 2 347 897 A1 , EP 2 730 696 A1 , EP 2 752 290 A1 and US 2015/0018461 A1 ). If an adhesive was selected that is compatible with the introduced VpCI / VCI components and hardens as a porous layer, you can actually achieve higher emission rates of these components than from foils in which the VpCI / VCI components were integrated during extrusion.

And finally, there are also suggestions to sprinkle a VpCI / VCI system as a finely dispersed powder directly into the film used as packaging material (see e.g.: US 8,603,603 ), it as a highly filled compact (so-called premix, cf. US 6,787,065 B1 ) next to the metal parts to be protected, or in the form of small granules in a flat, porous foam, on the other side of which a thin polyolefin film was laminated (see e.g.: US 5,393,457 and US 9,435,037 B2 ), further possibilities to present a low-resistance sublimating VpCI / VCI system within a film packaging with a relatively high proportion.

So far, however, all of these suggestions have been too expensive in terms of materials and materials, so that in practice experience shows that when designing high-performance corrosion protection packaging, preference is given to using the application variants of VpCI / VCI systems that have already been mentioned and can be described as classic.

As is well known, this also includes the VpCI / VCI-containing oils, although there is an ever-increasing demand for products that are suitable for VCI corrosion protection of components consisting of different metals and machining conditions. Such a VpCI / VCI-containing oil is known to be used not only for the metal substrate in question, on which it was applied as a thin film, but also for surface areas of the same component or neighboring metal objects that are on the surface Due to their geometry (e.g. holes, narrow notches, folded sheet metal layers) could not be coated with an oil film, protect them from corrosion. For this purpose, as with every VpCI / VCI depot mentioned above, it is again necessary that the VpCI / VCI components now emitted from the oil as carrier material do not pass through the vapor phase within closed rooms (e.g. packaging, containers, cavities) surface areas of metal parts covered with oil, where they form an adsorption film that protects against corrosion.

VpCI / VCI oils are, for example, in the patents US 919,778 , US 3,398,095 , US 3,785,975 , US 8,906,267 , US 1,224,500 and JP 07145490 A described. In that these VpCI / VCI oils emit volatile corrosion inhibitors and also protect the areas of metal surfaces not covered with oil by means of the gas phase, they differ significantly from preservative oils whose corrosion protection properties are improved by the introduction of non-volatile and therefore only effective direct contact with corrosion inhibitors were. Such anti-corrosion oils are, for example, in the patents US 5,681,506 , US 7,014,694 B1 and WO 2016/022406 A1 described.

Most of the VpCI / VCI oils that have become known so far have only been profiled for the VCI corrosion protection of ferrous materials. They usually contain higher proportions of one or more amines, so that a relatively high concentration gradient can be effective for their migration within the oil phase and their emission therefrom into the atmosphere of a closed package. The development phase required to develop its VCI effect is correspondingly short. The amine that has reached the metal surface to be protected via the gas phase in the water condensed there from moist air ensures an alkaline surface pH value at which the POL of common iron materials is stable (see, for example: E. Kunze (ed.) loc. cit.). Experience has shown that these amine-based VpCI / VCI oils are not suitable for VCI corrosion protection of non-ferrous metals (e.g. Al and Cu base materials) and galvanized steels, since their POL degrades at these high surface pH values with the formation of hydroxo complexes and subsequently uses corrosion.

Amines that already have a vapor or sublimation pressure under normal conditions to use as VCI / VpCI has been practiced for many years and has been described in numerous patents (see, for example: E. Vuorinen, et.al, loc.cit. And US 8,906,267 B2 ). Today, the cyclic amines dicyclohexylamine and cyclohexylamine are preferred (cf. e.g .: US 4,275,835 , US 5,393,457 , US 6,054,512 , US 6,464,899 B1 , US 9,435,037 and US 9,518,328 B1 ) and the various primary and tertiary alkanolamines, such as 2-aminoethanol and triethanolamine, or corresponding substitutes (see, for example: E. Vuorinen, et.al, loc.cit. and US 6,752,934 B2 and US 8,906,267 B2 ).

In contrast, the secondary amines previously recommended for use, such as diethanolamine, morpholine, piperidine, etc. hardly used technically after it became known that these are easily nitrosated to carcinogenic N-nitrosamines in air under normal conditions.

Since the cyclic amines and amino alcohols are liquid under normal conditions, they must first be converted into the solid state by salt formation for the above-mentioned applications (for example for powder-containing emitters or incorporation into polymeric carrier materials). The amine carbonates, nitrites, nitrates, molybdates and carboxylates in question, as the latter primarily the amine benzoates and caprylates, are among the most common VCI / VpCI for corrosion protection of ferrous materials (cf. e.g.: EP 0 990 676 B1 , US 4,124,549 , US 5,137,700 , US 393,457 , US 6,464,899 A1 , US 8,603,603 B2 , US 9,435,037 , US 9,518,328 B2 and JP 2016-117920 A ).

In the case of the amine carboxylates in particular, both the amine component and the associated carboxylic acid are volatile and as a result both reach the metal surface to be protected via the vapor phase. The surface pH value which is established there in the presence of water vapor is then usually in the neutral range, as a result of which the corrosion protection effect against non-ferrous metals is usually advantageously influenced. In contrast, as already emphasized, amines alone lead to higher alkaline surface pH values, which lead to signs of corrosion, particularly in the case of aluminum-based materials and galvanized steels.

Since amines usually have higher vapor pressures than the associated carboxylic acids under normal conditions, experience has shown that, particularly in films in which amine carboxylates have been incorporated as VCI / VpCI, the amine components are preferentially depleted with increasing time. However, this inevitably means that only the remaining carboxylic acids are then emitted from films of this type that have been in use or deposited for a long time. However, if only carboxylic acids reach the metal surfaces to be protected via the vapor phase, then there are small, acidic surface pH values in the presence of moist air. This prevents adsorption of the carboxylate species at the POL of the metal surface to be protected and thus counteracts corrosion inhibition (see, for example: NS Nhlapo, thesis "TGA-FTIR study of vapors released by volatile corrosion inhibitor model systems", fac. Chem. Engng., Univ. of Pretoria, SA, July 2013 ). In the case of iron materials in particular, however, there is initially no formation of visible corrosion products because, as is well known, their POL is converted into a thin iron carboxylate cover layer that is imperceptible without modern optical methods. However, since such thin salt-like conversion layers are porous, corrosion continues to occur in moist air on the iron base material present in the pores with the development of hydrogen with the formation of visible corrosion products, such as that on Al materials and galvanized steels under the action of acidic aqueous media practically immediately is. According to the available experience, VCI / VpCI preparations with amine carboxylates are at best suitable for the relatively short-term corrosion protection of iron materials, but are not suitable for the protection of mixed metal components.

The same applies to the use of the nitrites which act as passivators. With these salts of nitrous acid it can be achieved that the POL of iron materials is reproduced spontaneously if it has been destroyed by partial chemical dissolution or local mechanical removal (abrasion, erosion) (see e.g. E. Vuorinen, et.al, loc.cit. and US 6,752,934 B2 ). Therefore, they have been used for some time as VCI / VpCI. The relatively volatile salt dicyclohexylammonium nitrite (DICHAN) in particular has been used as a VCI for the protection of ferrous materials for more than 70 years (cf. e.g. Vuorinen et al, loc. Cit.). Until recently, this DICHAN has been mentioned in numerous patent specifications as a component of VCI / VpCI compositions (e.g.: US 5,393,457 , US 6,054,512 , US 6,752,934 B2 , US 9,435,037 , JP 2016-117920 A and EP 0 990 676 B1 ), but always only for VCI corrosion protection of ferrous materials. All known formulations containing DICHAN, in most cases supplemented by other components such as anhydrous molybdates, carboxylates, benzotriazole or tolyltriazole (see e.g.: US 5,137,700 , US 5,393,457 and US 6,054,512 ) have so far proven unsuitable for the protection of mixed metal components with aluminum and copper materials as well as for galvanized steels for various reasons.

In an effort to create VpCI / VCI packaging materials that can be used not only for the protection of ferrous materials, but at least also for galvanized steels and aluminum materials, various amine-free VpCI / VCI systems have been proposed in which a salt of nitrous acid ( Ammonium or alkali nitrite) is combined with other substances capable of sublimation, such as various saturated or unsaturated carboxylic acids or their alkali salts, a multiply substituted phenol and / or an aliphatic ester of a hydroxy-benzoic acid (see, for example: US 4,290,912 , US 6,464,899 B1 , US 6,752,934 , US 6,787,065 B1 , EP 1 641960 B1 and KR 1020160011874 A ).

Other proposals, however, prefer combinations of amines and nitrites, for example consisting of various saturated or unsaturated carboxylic acids or their alkali salts in combination with an aliphatic ester of a mono- or dihydroxy-benzoic acid, an aromatic amide and, if necessary, completed with benzotriazole or tolyltriazole for the Protection of Cu materials (see e.g.: US 4,124,549 , US 4,374,174 , US 7,824,482 ).

With the addition of selected sublimation-capable water-insoluble, but steam-volatile, multiply substituted phenols (see e.g.: US 4,290,912 , US 6,752,934 , US 7,824,482 , EP 1641960 B1 ), bicyclic terpenes and aliphatic substituted naphthalenes (see e.g.: US 6,752,934 ) succeeded in reducing the emission of the VpCI / VCI components contained in the respective substance combination even under normal conditions, especially in air of higher rel. To improve moisture and bring it to the level usual for amines. The one for both iron and the usual VCI corrosion protection resulting from non-ferrous metals, however, requires comparatively highly filled active substance depots, since in addition to the relevant VpCI / VCI components, even higher proportions of the substances acting as carriers must always be accommodated.

With the in the US 8,906,267 B2 The proposed VpCI / VCI combination, consisting of an aminoalkyl diol with C ₃ to C ₅ , a monoalkyl urea, a preferably multiply substituted pyrimidine and benzotriazole, was able to achieve good VCI corrosion protection with objects consisting of several metals and surface states without the addition of perform substances acting as carriers.

In particular, when VpCI / VCI combinations are incorporated into mineral or synthetic oils, inorganic and organic salts, such as alkali metal nitrites, nitrates and carboxylates, are unsuitable because they are not sufficiently soluble in them. Such VpCI / VCI oils have therefore mainly been formulated in the past by using amines as VCI components (see, for example: US 919,778 , US 1,224,500 , US 3,398,095 , US 3,785,975 and JP 07145490 A ), sometimes supplemented by other volatile additives such as C ₆ to C ₁₂ alkyl carboxylic acids and esters of unsaturated fatty acids (cf. US 3,398,095 ). In the JP 07145490 A preparations with ethanolamine carboxylates, morpholine, cyclohexylamine and various sulphonates are claimed. However, all these recipes have in common that under normal conditions, ie at temperatures <60 ° C, only the amine components are emitted and become effective as VpCI / VCI.

Such VpCI / VCI oils are therefore only suitable for VCI corrosion protection of iron-based materials. In the case of zinc and aluminum, as is known, together with condensed water, they usually cause the surfaces to be too alkalized, which results in severe corrosion with the formation of zincates or aluminates, before the hydroxides and basic carbonates, for which the term white rust is common, are formed. Copper materials, on the other hand, often suffer corrosion under the influence of amines with the formation of Cu amine complexes.

To counteract this deficiency, the in the US 8,906,267 B2 proposed VpCI / VCI combination of an aminoalkyl diol with C ₃ to C ₅ , a monoalkyl urea, a preferably multiply substituted pyrimidine and benzotriazole can be introduced into a mineral oil or synthetic oil via a solvent so that a VpCI / VCI oil is formed with which can be designed with good VCI corrosion protection for a wide range of common metals. In the meantime, it has proven to be disadvantageous that only relatively small proportions of the VpCI / VCI components can be introduced, so that the VCI effect, which is very good in the case of fresh preparations, decreases more and more during long-term applications. The same could be observed if such a VpCI / VCI oil was diluted with a normal mineral oil.

In order to meet the demand for oils equipped with VpCI / VCI for the temporary protection against corrosion of ferrous and non-ferrous metals with structurally determined small cavities, new types of VpCI / VCI systems are required, their use in practice does not have the disadvantages described connected is. Of particular interest are preparations that are not only a VpCI / VCI oil, but at least also VpCI / VCI dispensers (mixtures of powdered VpCI / VCI components in bags, capsules etc.) and coated VpCI / VCI packaging materials ( let papers, cardboards, foams) be processed.

With combinations of such VpCI / VCI, which are fully compatible with one another, particularly effective and long-life VCI corrosion protection packaging could be produced for the applications mentioned, e.g. preservative packaging of engine blocks treated with VpCI / VCI oil in containers closed with a lid, in which additional VCI-emitting bags, capsules or VCI-coated paper or foam blanks have been placed, so that even with long-term storage, the VpCI / VCI components must always be saturated with the VpCI / VCI components as a prerequisite for maintaining VCI corrosion protection to care.

The object of the invention is to provide improved evaporation or sublimation-capable corrosion-inhibiting substances and combinations of substances, which are both as a powder mixture and incorporated into coatings and oils under the climatic conditions of practical interest within the disadvantages of conventional volatile corrosion inhibitors which act via the vapor phase of technical packaging and analog sealed containers with sufficient speed from the corresponding depot, e.g. evaporate or sublimate a bag containing the VpCI / VCI components, a coating containing the VpCI / VCI components on a support such as paper, cardboard or foam, or an oil containing the VpCI / VCI components and after adsorption and / or Condensation on the surface of metal parts in this room ensures conditions under which the common metals are reliably protected against atmospheric corrosion.

Surprisingly, these objects were achieved according to the invention by providing the combination of substances according to claim 1. More specific aspects and preferred embodiments of the invention are the subject of the further claims.

1. (1) ein substituiertes 1,4-Benzochinon,
2. (2) ein aromatisch oder alicyclisch substituiertes Carbamat,
3. (3) ein mehrfach substituiertes Phenol und
4. (4) ein monosubstituiertes Pyrimidin.

The combination of substances according to the invention comprises at least the following components:

1. (1) a substituted 1,4-benzoquinone,
2. (2) an aromatic or alicyclic substituted carbamate,
3. (3) a multiply substituted phenol and
4. (4) a monosubstituted pyrimidine.

The proportions of the various components can vary depending on the specific field of application, and suitable compositions can easily be determined by a person skilled in the art in this field through routine tests.

In a preferred embodiment of the invention, the corrosion-inhibiting substance combination contains 1 to 30% by mass of component (1), 5 to 40% by mass of component (2), 2 to 20% by mass of component (3) and 0.5 to 10% by mass -% component (4), each based on the total amount of the combination of substances.

The substituted 1,4-benzoquinone is preferably selected from the group consisting of alkyl or alkoxy-substituted 1,4-benzoquinones, in particular tetramethyl-1,4-benzoquinone (duroquinone), trimethyl-1,4-benzoquinone, 2,6- Dimethoxy-1,4-benzoquinone (DMBQ), 2,5-dimethoxy-1,4-benzoquinone, 2-methoxy-6-methyl-1,4-benzoquinone and combinations thereof.

The aromatic or alicyclically substituted carbamate is preferably selected from the group comprising benzyl carbamate, phenyl carbamate, cyclohexyl carbamate, p-tolyl carbamate and combinations thereof.

The multiply substituted phenol is preferably selected from the group consisting of 5-methyl-2- (1-methylethyl) phenol (thymol), 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol) , 2-tert-butyl-4-methylphenol, 2,4,6-tri-tert-butylphenol, 2,6-dimethoxyphenol (syringol) and combinations thereof.

The monosubstituted pyrimidine is preferably selected from the group consisting of 2-aminopyrimidine, 4-aminopyrimidine, 2-methylpyrimidine, 4-methylpyrimidine, 5-methoxypyrimidine, 5-ethoxypyrimidine, 4-phenylpyrimidine, 2-phenoxypyrimidine, 4- (N, N- Dimethylamino) pyrimidine and combinations thereof.

In the corrosion-inhibiting combination of substances according to the invention, components (1) to (4) can, for example, be mixed together or dispersed in water or else premixed in a solvent which is miscible with mineral oils and synthetic oils.

This solubilizer is preferably an aryl alkyl ether alcohol customary for oil preparations, such as, for example, phenoxyethanol (Protectol PE), in which the components are present in dissolved or dispersed form.

The corrosion-inhibiting substance combinations according to the invention can, in addition to the components (1) to (4) according to the invention and optionally the solubilizer additionally also contain substances already introduced as vapor phase corrosion inhibitors individually or as a mixture thereof.

The composition of the corrosion-inhibiting material combinations according to the invention is preferably adjusted so that in the temperature range up to +80 ° C at rel. Humidity (RH) ≤ 98% evaporate or sublime all components with sufficient quantity and speed for the anti-corrosion protection.

According to the invention, these combinations of substances are used directly in the form of corresponding mixtures or incorporated according to known methods in the production of VpCI / VCI packaging materials and oil preparations, so that these packaging materials or oils act as a VCI depot and the corrosion protection properties of the combinations of substances according to the invention are particularly important can unfold advantageously.

In one embodiment, the corrosion-inhibiting material combinations are used as a volatile corrosion inhibitor (VPCI, VCI) in the form of fine powder mixtures or pellets (pellets) produced therefrom in the packaging, storage or transportation of metallic materials.

However, the corrosion-inhibiting substance combinations can also be incorporated in coating materials or coating solutions, preferably in an aqueous / organic medium, and / or colloidal composite materials, in order to use them to support materials such as paper, cardboard, foams, textile fabrics, textile nonwovens and similar fabrics during manufacture coating of VCI-emitting packaging materials and then using them within packaging, storage and transport processes.

In another embodiment, the corrosion-inhibiting combinations of substances are used to produce VCI corrosion protection oil, from which vapor phase corrosion inhibitors (VPCI, VCI) are emitted.

Such a VCI corrosion protection oil comprises a mineral oil or synthetic oil and 0.5 to 5% by mass, more preferably 0.8 to 3% by mass, based on the oil phase, of a corrosion-inhibiting combination of substances according to the invention, optionally in a solubilizer. The composition is preferably set so that from the VCI oil in the temperature range up to 80 ° C at rel. Humidity (RH) ≤ 98% evaporate or sublime all corrosion inhibitor components with sufficient quantity and speed for the anti-corrosion protection.

The combinations of substances according to the invention are primarily used to protect the wide range of customary metals, in particular iron, chromium, nickel, aluminum, copper and their alloys, as well as galvanized steels, in packaging and during storage in analog closed rooms from atmospheric corrosion.

The combinations of substances according to the invention are free of nitrites and amines and advantageously consist exclusively of substances which can be easily and safely processed according to methods known per se and which are to be classified as non-toxic and non-hazardous to the environment in the proportions to be used. They are therefore particularly suitable for the production of corrosion-protective packaging materials, which can be used inexpensively on a large scale and without any significant risk potential.

For the introduction of the substance combinations according to the invention into VpCI / VCI depots or into packaging materials and oils functioning as such, it is generally advisable to first mix the individual substances in the water-free state as intensively as possible using methods known per se.

The substance combinations according to the invention are preferably formulated within the following mass ratios: Component (1): 1 to 30% Component (2): 5 to 40% Component (3): 2 to 20% Component (4): 0.5 to 10%.

The subject of the application is explained in more detail by the following examples. As can also be seen from this, the type, proportion of the individual components in the mixture according to the invention and proportion of mixture in the respective VpCl / VCI depot depend only on the production conditions of the relevant VpCI / VCI-emitting product and the processing aids required for this, but not on the type of metal to be protected against corrosion.

Example 1:

The following preparation VCI (1) according to the invention was produced using the anhydrous components of the combination of substances according to the invention and further anhydrous substances serving as processing aids: 10.0 mass% Tetramethyl-1,4-benzoquinone (duroquinone) 8.0 mass% Benzyl carbamate 6.0 mass% 5-methyl-2- (1-methylethyl) phenol (thymol), 6.0 mass% 5-ethoxypyrimidine, 20.0 mass% Silica gel (SiO ₂ ) 10.0 mass% Sodium benzoate, (micronized, d ₉₅ ≤ 10 µm) 8.0 mass% 1-H benzotriazole 1.0 mass% 2- (2H-benzotriazol-2-yl) -p-cresol (Tinuvin P, CIBA) 30.0 mass% non-polar PE wax (CWF 201, ALROKO) 1.0 mass% Calcium stearate (d ₉₅ ≤ 8 µm)

In each case 0.5 g of this carefully homogenized powder mixture was filled into a prefabricated small bag made of Tyvek ® 1057 D (54 g / m ² ), a vapor-permeable plastic film, the opening of which was sealed and this bag was then poured out onto a perforated bottom insert PMMA, which ensures a distance of approx. 15 mm from the base of the mason jar used to hold the test arrangement (Weck® is a registered trademark) (volume 1 l). 15 ml of deionized water had previously been metered in under this floor insert. In addition to the filled Tyvek® bag, a 5 mm deep notch made of PMMA was placed on the floor insert. In there 4 pieces of carefully cleaned test sheets (90 x 50 xd) mm of different types were positioned upright with approx. 15 ° inclination to the horizontal at a distance of 10 mm from each other. For each mason jar there were 1 test sheet made of DC 03 steel, cold-rolled, low-carbon, material no. 1.0347, d = 0.5 mm, aluminum 99.5, d = 0.625 mm (both Q-Panel Cleveland), Cu-ETP (MKM Mansfelder Kupfer und Messing GmbH), d = 0.5 mm and hot-dip galvanized steel DX56D + Z140MBO (Fine grain zinc coating 140g / m ² - 70/70 g / m ² - 10 µm, ArcelorMittal), d = 0.8 mm.

The mason jars with the test sheets, the deionized water and the combination of substances according to the invention were tightly sealed, for which purpose a lid with a sealing ring and three tension clamps were used. After a waiting time of 16 hours at room temperature, the so-called build-up phase of the VCI components within the vessel could be considered complete. The individual mason jars were then exposed for 16 h in a heating cabinet according to DIN 50011-12 at 40 ° C, then again for 8 h at room temperature. This cyclic load (1 cycle = 24 h) was briefly interrupted after every 7 cycles, the mason jars were opened for approx. 2 minutes to replace any oxygen in the air and to inspect the surface condition of the sheets. The exposure was terminated after a total of 35 cycles and each test specimen outside the mason jars was visually assessed in detail.

In reference to the mixture of substances VCI (1) according to the invention, 0.5 g portions of a commercially available VCI powder were tested in the same way. This reference VCI powder (R1) consisted of 28.8 mass% Dicyclohexylamine benzoate 67.1 mass% Cyclohexylamine benzoate 1.5 mass% 1-H benzotriazole 2.6 mass% Silica gel (SiO ₂ )

Result of the exam:

The test sheets of the 4 different metals, which had been used together with the material mixture VCI (1) according to the invention, had an unchanged appearance after 35 cycles in all 4 parallel batches.

In the approaches with the commercially available R1 reference system, only the sheets from DC 03 were still free of corrosion after 35 cycles. The sheets made of Al 99.5 were coated on both sides with a yellowish-brown tarnish layer and individual white punctiform precipitates, the sheets made of Cu-ETP each had dark spots starting from the top to a black tarnish layer. The test sheets made of galvanized steel were characterized by the first patch-like approaches of white rust in most of the batches after 7 cycles in the edge areas, which had become more extensive during the further test cycles.

The commercially available R1 reference system is therefore only suitable for VCI corrosion protection of iron base materials. In comparison to this, the example described describes the VCI effect of the substance combination VCI (1) according to the invention in a very advantageous manner compared to the customary metals.

Example 2

A coating agent VCI (2) of the following composition was produced by introducing anhydrous components of the combination of substances according to the invention and further substances required as processing aids into an aqueous polyacrylate dispersion (PLEXTOL ® BV 411, PolymerLatex): 1.0 mass% 2,6-dimethoxy-1,4-benzoquinone (DMBQ) 1.0 mass% Benzyl carbamate 1.5 mass% Thymol 2.5 mass% 2-aminopyrimidine 55.0 mass% PLEXTOL BV 411 6.0 mass% Methyl ethyl ketone 16.0 mass% deionized water 10.0 mass% Sodium benzoate, (micronized, d ₉₅ ≤ 10 µm) 6.0 mass% Polymer thickener (Rheovis VP 1231. BASF) 1.0 mass% Defoamer (AGITAN 260/265, MÜNZING Chem.) and thus coated paper webs (kraft paper 70 g / m ² ) with a wet application of 15 g / m ² . Immediately after the VCI paper VCI (2) according to the invention thus produced was dried in air, it was tested for its anti-corrosion effect in comparison with a commercially available anti-corrosion paper serving as a reference system (R2).

• 6,2 Masse-% Triethanolamincaprylat
• 3,4 Masse-% Monoethanolamincaprinat
• 1,4 Masse-% Benzotriazol
• 6,7 Masse-% Natriumbenzoat

According to chemical analysis, the commercially available reference system (R2) with a grammage of 66 g / m ² contained the following active ingredients:

• 6.2% by mass of triethanolamine caprylate
• 3.4 mass% monoethanolamine caprinate
• 1.4 mass% benzotriazole
• 6.7 mass% sodium benzoate

In comparison with the combination of substances according to the invention in the preparation VCI (2), the total proportion of active ingredient components in the reference system (R2) was approximately three times higher.

For comparative testing, test sheets made of DC 03 steel, cold-rolled, low-carbon, material no. 1.0347, d = 0.5 mm, aluminum 99.5, d = 0.625 mm (both Q-Panel Cleveland), Cu-ETP (MKM Mansfelder Kupfer und Messing GmbH), d = 0.5 mm and hot-dip galvanized steel (fine grain Zinc coating 140g / m ² - 70/70 g / m ² - 10 µm, ArcelorMittal), d = 0.8 mm for use. The test ritual again corresponded to that described in Example 1. The only difference was that instead of the VCI powder mixture given in a Tyvek bag, the individual mason jars were now lined with the VCI paper. This was done with 1 circular blank with Ø 8 cm on the bottom, a jacket of 13 x 28 cm and another circular blank with Ø 9 cm for the lid, always with the coated side facing the insert with the test sheets to be protected against corrosion. After the 15 ml of deionized water had been poured in again and the notched bar with the 4 test plates had been placed on the perforated bottom, the mason jar was closed and the climatic stress was carried out as described in Example 1.

A waiting time of 16 h at room temperature was initially specified as the so-called build-up phase of the VCI components within the closed vessel. The individual mason jars were then exposed again for 16 h in a heating cabinet according to DIN 50011-12 at 40 ° C, then for 8 h at room temperature. This cyclic load (1 cycle = 24 h) was briefly interrupted after every 7 cycles, the mason jars were opened for approx. 2 minutes to replace any oxygen in the air and to inspect the surface condition of the sheets. The exposure was ended after a total of 35 cycles and each test sheet outside the mason jars was visually assessed in detail.

Result of the exam:

The various test sheets which had been used together with the VCI paper VCI (2) produced on the basis of the material mixture according to the invention had an unchanged appearance after 35 cycles in all 4 parallel batches.

In the approaches with the commercially available R2 reference system, only the test sheets from DC 03 remained free of visible rust products during the 35 cycles, but were characterized by a matt appearance compared to the initial state. The test sheets made of Al 99.5 had dark, non-wipeable tarnish films on both sides.

The first signs of white rust were found on the edges of the galvanized steel test sheets after only 7 cycles, which also increased significantly over the surface area as the load continued. The appearance of the Cu-ETP test panels was inconsistent after 35 cycles. While the appearance of the sheet metal surfaces had remained unchanged in 2 approaches, the sheets in question in the remaining approaches had covered in places with a thin, non-wipeable black tarnishing film. This finding could not be excluded even when the tests were repeated.
The R2 reference system is therefore only suitable for VCI corrosion protection of iron base materials, while with Cu base materials the active substances emitted from the R2 reference system are obviously adsorbed in such different specific concentrations that defects in the VCI corrosion protection effect result. In contrast, that has VCI paper VCI (2) produced on the basis of the combination of substances according to the invention, as the example shows, exhibits reliable VCI properties compared to the usual consumer metals even under the extreme humid air conditions with long-term exposure.

Example 3:

A corrosion protection oil VCI (3) of the following composition was produced by adding water-free components of the combination of substances according to the invention and other substances required as processing aids to a commercially available mineral oil: 0.6 mass% Duroquinone 0.1 mass% Benzyl carbamate 0.2 mass% Thymol 0.2 mass% 4-phenylpyrimidine 92.7 mass% Mineral oil with normal wax thixotropic agent (BANTLEON® base oil LV 16-050-2) 6.0 mass% Phenoxyethanol 0.2 mass% Tolyltriazole (TTA, COFERMIN®)

After intensive stirring, the VCI oil VCI (3) according to the invention resulted as an optically clear fluid, characterized by an average kinematic viscosity of 25 ± 3 mm ² / s (20 ° C.). In reference to the VCI oil VCI (3) according to the invention, a commercially available VCI oil of approximately the same average kinetic viscosity was tested in an analogous manner. This reference VCI-ÖI R3, also formulated on the basis of a mineral oil, contained the active ingredients after chemical analysis: 11.3 g / kg Dicyclohexylamine 8.2 g / kg Diethylamino ethanol 15.1 g / kg 3.5.5 Trimethylhexanoic acid 3.6 g / kg Benzoic acid.

For comparative testing, test sheets made of DC 03 steel, cold-rolled, low-carbon, material no. 1.0347, d = 0.5 mm, aluminum 99.5, d = 0.625 mm (both Q-Panel Cleveland), Cu-ETP (MKM Mansfelder Kupfer und Messing GmbH), d = 0.5 mm and hot-dip galvanized steel (fine-grain zinc coating 140g / m ² - 70/70 g / m ² - 10 µm, ArcelorMittal), d = 0.8 mm, for use. The test ritual again corresponded to that described in Example 1.

The main difference now was that the notched bars made of PMMA serving as test specimen frames were now each equipped with 3 pieces of the same type of test specimen and the centrally positioned test plate was covered on both sides with the VCI oil to be tested, while the distance from approx. 10 mm laterally arranged test sheets were used without oil. It was thus possible to determine to what extent the oil film applied to the centrally positioned test sheet is capable of both the metal substrate directly exposed to it and the two test sheets not covered with an oil film due to the emission of the VCI components via the vapor phase within the closed mason jar Protect corrosion.

Each mason jar (volume 1 l) consequently now contained the notched PMMA bar with the relevant 3 test sheets of the same material on the perforated base insert and the 15 ml of deionized water dosed underneath. After the individual mason jars were closed, the climatic stress was carried out as described in Example 1.

A waiting time of 16 h at room temperature was initially specified as the so-called build-up phase of the VCI components within the closed vessel. The individual mason jars were then exposed again for 16 h in a heating cabinet according to DIN 50011-12 at 40 ° C, then for 8 h at room temperature. This cyclic load (1 cycle = 24 h) was briefly interrupted again after every 7 cycles, the mason jars were opened for approx. 2 minutes in order to replace any oxygen that had been converted and to inspect the surface condition of the sheets. The exposure was ended after a total of 35 cycles and each test sheet outside the mason jars was visually assessed in detail.

Result of the exam:

The various test sheets, one of which was coated with the VCI oil VCI (3) according to the invention together with 2 similar, non-oiled test sheets at a distance in a mason jar, had been exposed to the cyclical humid air climate, had an unchanged appearance after 3 cycles after 3 parallel runs. The VCI oil VCI (3) according to the invention consequently ensured good corrosion protection both for the metal substrates in question in direct contact and for the test sheets not exposed to the oil inside the sealed mason jar due to the VCI components emitted via the vapor phase.

In the approaches with the commercially available R3 reference system, the test sheets made of the low-alloy steel DC 03 likewise showed no signs of corrosion, either in the oiled or in the unoiled state, after 35 cycles. In the case of test sheets made of Al 99.5, Cu-ETP and galvanized steel, however, this was only the case when they were oiled.

The test plates made of Al 99.5, which were not lubricated, were covered with a brown tarnish film after 35 cycles, which was mostly more pronounced at the edges of the plates. On the unoiled Cu-ETP test sheets, dark gray to black-looking stains could already be observed after 7 cycles at the upper edge areas, from which after 35 cycles in most cases relatively uniform, non-wipeable tarnish films had formed.

The most noticeable changes were the changes made to the non-oiled test sheets made of the fine-grain galvanized steel. Here, after 7 cycles of exposure to moist air, preferential spots of white rust could be observed at the edges, from which larger, light gray to white-looking spots had formed with continued exposure to the moist air.

The reference system R3 can therefore only be used in direct contact with the corrosion protection in comparison to the usual metals. The active substances emitted from it in the gas phase, on the other hand, are only suitable for VCI corrosion protection of iron-based materials. The VCI oil VCI (3) according to the invention ensures on the other hand, as the example shows, a pronounced multi-metal protection, in that it develops reliable VCI properties in long-term tests compared to the usual metals, even under the extreme humid air conditions.

Claims (15)

1. A corrosion-inhibiting substance combination capable of evaporation or sublimation, comprising at least:

   (1) a substituted 1,4-benzoquinone,

   (2) an aromatic or alicyclic substituted carbamate,

   (3) a polysubstituted phenol, and

   (4) a monosubstituted pyrimidine.
2. The corrosion-inhibiting substance combination according to claim 1, which comprises 1 to 30 mass % of component (1),
   5 to 40 mass % of component (2),
   2 to 20 mass % of component (3), and
   0.5 to 10 mass % of component (4),
   each relating to the total quantity of the substance combination.
3. The corrosion-inhibiting substance combination according to claim 1 or 2, wherein the substituted 1,4-benzoquinone is an alkyl- or alkoxy-substituted 1,4-benzoquinone.
4. The corrosion-inhibiting substance combination according to one of the preceding claims, wherein the substituted 1,4-benzoquinone is selected from the group comprising tetramethyl-1,4-benzoquinone (duroquinone), trimethyl-1,4-benzoquinone, 2,6-dimethoxy-1,4-benzoquinone (DMBQ), 2,5-dimethoxy-1,4-benzoquinone, 2-methoxy-6-methyl-1,4-benzoquinone as well as combinations of the same.
5. The corrosion-inhibiting substance combination according to one of the preceding claims, wherein the aromatic or alicyclic substituted carbamate is selected from the group comprising benzyl carbamate, phenyl carbamate, cyclohexyl carbamate, p-tolyl carbamate as well as combinations of the same.
6. The corrosion-inhibiting substance combination according to one of the preceding claims, wherein the polysubstituted phenol is selected from the group comprising 5-methyl-2-(1-methylethyl)-phenol (thymol), 2,2'-methylene-bis-(4-methyl-6-tert.-butylphenol), 2-tert.-butyl-4-methylphenol, 2.4.6-tri-tert.-butylphenol, 2.6-dimethoxyphenol (syringol) as well as combinations of the same.
7. The corrosion-inhibiting substance combination according to one of the preceding claims, wherein the monosubstituted pyrimidine is selected from the group comprising 2-aminopyrimidine, 4-aminopyrimidine, 2-methylpyrimidine, 4-methylpyrimidine, 5-methoxypyrimidine, 5-ethoxypyrimidine, 4-phenylpyrimidine, 2-phenoxypyrimidine, 4-(N,N-dimethylamino)pyrimidine as well as combinations of the same.
8. The corrosion-inhibiting substance combination according to one of the preceding claims, which also contains substances already introduced as vapour phase corrosion inhibitors in addition to components (1) to (4) according to the invention, either individually or as a mixture of the same.
9. A VCI corrosion protection oil, comprising a mineral oil or synthetic oil and a corrosion-inhibiting substance combination according to one of the claims 1-8, preferably in a proportion of 0.5 to 5 mass %, more preferably 0.8 to 3 mass %, optionally in a solubilizer.
10. A method for manufacturing a corrosion-inhibiting substance combination capable of evaporating or sublimating, wherein at least (1) a substituted 1,4-benzoquinone, (2) an aromatic or alicyclic substituted carbamate, (3) a polysubstituted phenol and (4) a monosubstituted pyrimidine are mixed with each other.
11. The method according to claim 10, wherein 1 to 30 mass % component (1), 5 to 40 mass % component (2), 2 to 20 mass % component (3), and 0.5 to 10 mass % component (4) are mixed with each other.
12. Use of a corrosion-inhibiting substance combination according to one of the claims 1 to 8 as a volatile corrosion inhibitor (VpCI, VCI) in the form of fine powder mixtures or briquettes (pellets) manufactured from the same during the packaging, storage or transport of metal materials.
13. Use of a corrosion-inhibiting substance combination according to one of the claims 1 to 8 for incorporation into coating materials or coating solutions, for coating carrier materials such as paper, cardboard, foamed materials, textile fabrics and similar flat fabrics with the same.
14. Use of a corrosion-inhibiting substrate combination according to one of the claims 1 to 8 for manufacturing a corrosion protection oil from which vapour phase corrosion inhibitors (VpCI, VCI) are emitted.
15. Use of a corrosion-inhibiting substance combination according to one of the claims 1 to 8 or a VCI corrosion protection oil containing the same, for the corrosion protection of common commodity metals such as iron, chromium, nickel, aluminium, copper and their alloys as well as galvanised steels, in particular during packaging, storage and transport processes.