EP0861925A1 - Corrosion inhibiting composite material - Google Patents

Abstract

Corrosion-inhibiting composite material consists of a metal oxide gel (I) and corrosion inhibitor(s) (II). Also claimed is a method of producing the composite.

Description

The invention relates to a corrosion-inhibiting material, that contains one or more corrosion inhibitors.

It is known that corrosion inhibitors, which tend to sublime in powder form under normal conditions and can reach metal surfaces to be protected via the gas phase, are used for the temporary corrosion protection of metal objects inside closed rooms, for example in packaging or display cases. These so-called vapor phase inhibitors (VPI) or volatile corrosion inhibitors (VCI) are usually used as a powder, packaged in bags made of a material that is permeable to the vaporous VPI's.

Variants of this type are e.g. from H. H. Uhlig "Corrosion and Corrosion Protection ", Akademie-Verlag Berlin, 1970, p. 247 ff., or I.L. Rozenfeld "Corrosion Inhibitors" (Russian), Izt-vo Chimija, Moskva 1977, pp. 316 ff. You own it Disadvantage that the release of the VPIs is undefined and a homogeneous distribution over the gas space is not guaranteed can be. Other disadvantages are the risk that the CPI contained Bags are mechanically destroyed and become an undesirable one Contamination of the packaged goods as well the problems arising from the uneven distribution of the Bags in large storage rooms and large containers surrender.

There are many ways to remedy these disadvantages been tried. It is proposed in US 3,836,077 that Use VPI mixture in the form of pressed pellets and thereby either completely towards a gas-permeable container material waive or put the pellets in with appropriate To use recessed foams. In patents US 3,967,926; US 5,332,525 and US 5,393,457 it is suggested, however, that the VPI's be chemically inert Powder or a desiccant such as silica gel or zeolite to mix and in mechanically more stable, air-permeable Plastic films or capsules instead of those used previously Bags made from natural products (cotton, linen, etc.) are used bring to. The inert carrier material is said to be due to its structure-related porosity for continuous sublimation of the VPI components distributed in between and at the same time an agglomeration of the finely dispersed VPI components to larger mixed particles (e.g. formation of lumps counteract with encrusted surface due to water absorption). However, the use of desiccants has been common the opposite of the desired effect and leads after water absorption for preferred clumping. Also have the mechanically more stable container materials for the VPI's less permeability than natural products, so that their emission rate drops. Therefore it is necessary to stop the VPI concentration required for corrosion protection greater number of VPI reservoirs than when using Containers made from natural products. With this disadvantage the temporary corrosion protection, especially in large dimensions Interiors more difficult and more expensive.

So that within the framework of automated packaging technologies elaborate step of evenly distributing VPI reservoirs can be dispensed with in the interior of packaging The VPI's have been tried many times in a suitable manner to fix directly on the packaging. Naturally dominated first of all experiments with cardboard and packing paper. Around to ensure that the CPIs applied are directed towards the The interior of packaging emit the VPI components usually applied to only one side while the other side, later arranged as the outer front, with a Protective varnish is provided, which in turn is water-repellent and also as a vapor barrier for those on the back VPI can act (see e.g. H.H. Uhlig, see above). As Up to the present day, the dimensions and quantity-stable fixation of the VPI on the surface of cardboard or wrapping paper. Will the CPI be within an organic Coating material applied, then a variety of Substances that are effective as a CPI are not used because chemical reactions with the binder of the coating material enter, causing them into the resulting polymeric matrix be firmly integrated and no longer for sublimation are qualified. This disadvantage shows e.g. VPI's in polymer Binder based on acrylic, alkyd, epoxy or phenolic resin were embedded.

Alternatively, the VPI's are in an organic solvent solved and soaked the packaging. method of this type with various active ingredients and solvents are e.g. in JP 61-227188, JP 62-063686, JP 63-028888, JP 63-183182, JP 63-210285 and US 3 887 481. It proved but consistently considered disadvantageous that the CPI's after the evaporation of the solvent within the pores of the concerned Substrate in the form of fine crystals, which adhere only slightly to the packaging material. As a result the risk of these substances spreading and trickling out from or out of the packaging, so that not secured can be that the pretreated cardboard and paper for Time of their application for corrosion protection at all the required specific surface concentration of VPI have.

In order to limit this disadvantage at least to its extent, is proposed in DE 9210805, only one layer of the corrugated cardboard structure as a carrier and depot for the sublimable corrosion inhibitors prepare and double-sided with at least another porous layer so that the VPI depot located inside the cardboard. But because of that the levy the CPI's deteriorated inside the packaging, is proposed in JP 4 083 943 instead of corrugated cardboard or Paper to use a polyurethane foam that is essential has higher porosity and therefore much larger quantities VPI can absorb. But it is also the disadvantage here record that the VPI's in the pores of the foam after evaporation of the solvent crystalline and little adherent so that the mechanical stress of the Pour the packaging materials out of the VPI easily and uncontrollably can.

JP 58-063732 and US 4,275,835 therefore describe methods in which the VPI's are components of the foamed polymer. For this it is necessary that the crystalline VPI's in one of the Starting components are dispersed. This is despite one high technical and energy expenditure only imperfectly possible, since VPIs usually belong to other substance classes and the stability of the Dispergate is low. Aggravating Added to this is the fact that the modern VPI's themselves consist of several substances with different chemical properties. Provided these are at all together with the components for foams Such dispersions usually have dispersed a very wide range of grain sizes, low stability and problematic workability.

DD 295 668 describes a process for producing VPI containing polyurethane systems, in which the VPI's initially in a polyfunctional alcohol of molecular weight 500 to Dissolved 1000 g / mol and then introduced into the polyol be before adding polyisocyanate, catalyst, stabilizer and blowing agent the polyurethane is produced. This However, the procedure is only limited to VPIs in such Alcohols in the concentration required for corrosion protection are soluble and then as part of the polyol component do not interfere with the process of foaming. It is therefore not suitable to meet the complex requirements meet the temporary corrosion protection of today Ferrous and non-ferrous metals as well as multi-metal combinations be made, especially since it contains practically all inorganic active substances excludes from the application.

To eliminate the disadvantages mentioned and VPI-emitting To provide packaging that is in modern Apply packaging, storage and transportation technologies is in US 4 124 549, US 4 290 912, US 5 209 869, EP 0 639 657 and DE-OS 3 545 473 proposed the VPI's during the extrusion of polyolefin films, so that a mechanically stable polymeric packaging material from which the CPIs are issued. EP 0 662 527, DE-OS 4 040 586, DE-OS 3 518 625 and US 5 139 700 suggest refining before, such a VPI-containing film based on polyethylene or polypropylene only in the context of laminated multilayer materials to use. One should face outwards Layer of Al foil or a densely cross-linked Polymer layer, which are compared to those from the VPI-containing Position emitted active substances acts as a vapor barrier and the directional transport of the VPI into the interior of the packaging prompted. The production of inhibitor-containing polymer films by extruding a mixture that tends to sublime Containing substances is, of course, with a number of difficulties connected: (a) the high volatility of the CPIs at temperatures, in which the extrusion process is carried out leads to significant losses of these substances and foaming the film, to violate its unity and thus for the uncontrolled reduction in their strength and Protective properties, (b) there is the possibility of thermal Decomposition of the corrosion inhibitors and undesirable thermochemical reactions with the polymer matrix. This results as a major disadvantage that it is on this path hardly a packaging material with uniform surface properties reproducibly.

The object of the invention is to provide an improved material mechanically and chemically stable fixation of volatile Corrosion inhibitors on solid surfaces and a corrosion protective Specify packaging material. The fixative Material should in particular be independent of the physicochemical Properties of the active ingredients and the type of surface be universal and technologically easy to use and eliminate the disadvantages of the methods described above. task the invention further is a method of manufacture of such material.

These tasks are accomplished with a corrosion inhibiting composite material, a packaging material and a process with the features of claim 1, 7 and 10 solved. Beneficial Embodiments of the invention result from the subclaims.

Surprisingly, according to the invention, the task in particular can be solved in that known corrosion inhibitors in diffusion-inhibiting metal oxide gels (preferably in Layer form) are embedded, the inorganic matrix can be modified by organic polymers so that synergistic Effects regarding immobilization and layer quality result. By choosing the composition of the metal oxide gel and the manufacturing technology allows the porosity of the composites formed so that a stable Release of the corrosion inhibitor into the gas phase via a long period of time.

The corrosion-inhibiting composite material is used in manufacturing of corrosion protective packaging materials, for coating of metallic and metallized objects as well as for corrosion protection in closed rooms.

The invention relates to a corrosion-inhibiting material, consisting of a composite containing a metal oxide gel, possibly modified by an organic polymer, and one or more Contains corrosion inhibitors, a process for its preparation, or the use of a corrosion-inhibiting Composite material for the production of anti-corrosion Packaging materials, for coating metallic and metallized objects and for corrosion protection in closed Clearing

Metal oxide gels such as Si0 ₂ , Al ₂ 0 ₃ , Ti0 ₂ , Zr0 ₂ or ZnO or mixtures thereof can be used as the matrix component, which can be obtained by a sol-gel process, for example by hydrolysis of the corresponding metal alkoxides to give the corresponding metal oxide sols and subsequent ones Gel formation by neutralization, heating or concentration, receives, cf. JCBrinker, GWScherer, "Sol-Gel Science", Academic Press, London 1990. The metal oxide brine is formed by acid or base-catalyzed hydrolysis of the corresponding metal alkoxides in water or any water-miscible organic solvent (usually ethanol). : Me (OR) _n + n / 2 H ₂ 0 → (MeO _m ) _sol + n R0H (Me = metal e.g. Si, Al, Ti, Zr, Zn, R = organic residue, e.g. alkyl, acyl)

1. Die Sole gelieren bei pH-Änderung oder Temperaturerhöhung zu wasserklaren Gelen, die beim Trocknen poröse Pulver ergeben (MeO_m)_sol → (MeO_m)_gel

2. Die Sole gelieren beim Beschichten beliebiger Folien oder Formkörper und bilden transparente Filme (oder klare Filme).

3. Man kann in den Solen unterschiedliche Wirkstoffe lösen und nach Gelierung wirksam und homogen in das Metalloxid-Gerüst einbetten. Es entstehen sog. Metalloxid-Wirkstoff-Komposite (als Pulver oder Film). Der Wirkstoff ist wie eine feste Lösung molekular-homogen oder molekular-dispers in der Metalloxid-Matrix verteilt.

The metal oxide brines are water-clear, stable solutions with a metal oxide content between 3 ... 20%. The metal oxide particles are in nanocrystalline spherical form (approx. 2 ... 5 nm). The solvent is freely selectable. The metal oxide brines show the following special features:

1. When the pH changes or the temperature rises, the brine gels to form water-clear gels which form porous powders when dried (MeO _m ) _sol → (MeO _m ) _gel

2. The brine gels when coating any films or moldings and forms transparent films (or clear films).

3. Different active ingredients can be dissolved in the brine and, after gelation, embedded effectively and homogeneously in the metal oxide structure. So-called metal oxide / active substance composites are formed (as powder or film). The active ingredient is distributed in the metal oxide matrix like a solid solution in a molecularly homogeneous or molecularly disperse manner.

The active ingredient content in the metal oxide is around 1 to 15% by weight, preferably around 1 to 5% by weight, based on the weight of the Metal oxide in the sol (solids content) or in the gel.

For the modification of the layer properties, the hydrolysis process (1) of the metal alkoxides can be carried out in the presence of mixed alkyl trialkoxysilanes R-Si (OR ') ₃ , whereby modified metal oxide gels are formed which, based on 1 part by weight of metal oxide gel, contain 0 to 1 part by weight of R-Si0 _n contain. R is an organic alkyl radical, which may contain amino, hydroxy or alkoxy groups, R 'is an alkyl radical, primarily with 1-4 carbon atoms and n is <2. This form of modification allows the mechanical properties of the layer to be improved and the layer porosity to be varied.

Another possibility to modify the metal oxide gel for Improvement of the layer quality is that 1 part by weight Metal oxide gel by 0 to 1 parts by weight of a dissolved or dispersed organic polymers such as cellulose derivatives, Starch derivatives, polyalkylene glycols or their derivatives, Homo- or copolymers based on acrylate and methacrylate, Polystyrene sulfone sulfonate or natural resins, or mixtures of the polymers mentioned, is modified. Examples of preferred Polymers as a composite component are polystyrene sulfonic acid, Hydroxypropyl, methyl and carboxymethyl cellulose or rosin. The polymer additive has two functions: (a) supported by changing the composite structure by ionic groups as in the case of polystyrene sulfonate, you can delay the release of the corrosion inhibitor, (b) by the addition of polymer, especially soluble Cellulose derivatives, one can adjust the viscosity of the brine and thus the layer thickness under constant coating conditions increase sharply. So you are able to get the absolute amount of the released corrosion inhibitor Taxes.

All substances whose Presence inhibits corrosion, for example substituted Phenols, hydroquinone and quinone derivatives, nitrites, organic Acids, salts of organic acids, aliphatic or aromatic Amines, amides, thiazoles, triazoles, imidazoles or mixtures thereof be used. Depending on solubility, volatility and Molecular weight, their proportion in the composite can be 1 to 50% by weight. be.

(a) Herstellung eines Metalloxidsols, welches Si0₂, Al₂0₃, Ti0₂, Zr0₂ oder ZnO oder Gemische der Metalloxide enthält, bzw. durch R-Si0_n modifiziert sein kann, durch Hydrolyse der entsprechenden Metallalkoxide in einem wäßrigen, organischen oder gemischten Lösungsmittel, ggf. unter Zusatz von verdünnter Mineralsäure, wäßrigem Alkali, Fluorid oder tertiären Aminen als Hydrolysekatalysator. Als organisches Lösungsmittel wird vorzugsweise Ethanol, Aceton oder Dioxan verwendet.

(b) Wahlweiser Zusatz gelöster oder dispergierter Polymere zur Modifizierung der Schichteigenschaften, wobei dessen Anteil in Bezug auf das Metalloxid Sol so gewählt wird, daß das resultierende modifizierte Metalloxid-Sol eine Viskosität von mindestens 5 mPa/20°C aufweist. Der Polymeranteil liegt typischerweise in einem Bereich von 0.1...20 % Gewichts-% bezogen auf das Metalloxid.

(c) Lösen des Korrosionsinhibitors in dem ggf. polymermodifizierten Metalloxidsol. Der Inhibitor kann auch vor oder während der hydrolytischen Bildung der Metalloxidsole (1) zugemischt werden, wenn er stabil gegenüber den Hydrolysebedingungen (pH- und Lösungsmittel-Milieu) ist. Für den Einsatz anorganischer Inhibitoren wie Natriumnitrit ist es aufgrund der begrenzten Löslichkeit in organischen Lösungsmitteln empfehlenswert, den Anteil organischer Lösungsmittel im Metalloxidsol gering zu halten, um Ausflockungen zu vermeiden. Das läßt sich z.B. leicht durch destillative Entfernung des organischen Lösungsmittels bei gleichzeitiger Zugabe der volumenäquivalenten Menge Wasser erreichen. Auf diese Weise erhält man hinreichend stabile, rein wäßrige modifizierte Metalloxidsole, die mit den wasserlöslichen anorganischen Korrosionsinhibitoren homogene Mischungen ergeben.

(d) Gelieren des inhibitorhaltigen Metalloxidsols durch Erwärmen oder Neutralisieren zur Herstellung von bulk-Produkten, z.B. zur Herstellung eines pulverförmigen korrosionsinhibierenden Kompositmaterials, oder durch Beschichten des wirkstoffhaltigen Metalloxidsols auf einen Träger, beispielsweise auf Papier, Karton, polymere Folien oder Schaumstoffe, textiles Gewebe oder auf unmittelbar zu schützende metallische oder metallisierte Gegenstände. Die Beschichtung kann durch übliche Beschichtungstechniken wie durch Tauchen ("Dip Coating"), Sprühen ("Spray Coating"), Schleudern ("Spin Coating"), Streichen oder Begießen erfolgen. Für die Beschichtung von Schaumstoffen ist es günstig, den durchtränkten Schaumstoff vor der Trocknung durch einen Walzenstuhl laufen zu lassen. Durch den Walzenabstand kann man die bequem die gewünschte Beladung mit dem korrosionsinhibierenden Kompositmaterial einregulieren.

(f) Das Entfernen des Lösungsmittels kann durch übliche Trocknungsverfahren wie Luft-, Vakuum- oder Gefriertrocknung erfolgen. Die Trockenschichtdicken liegen typischerweise in einem Bereich von 0.08...2 µm.

The process for producing a corrosion-inhibiting composite material is carried out in the following steps:

(a) Production of a metal oxide sol which contains Si0 ₂ , Al ₂ 0 ₃ , Ti0 ₂ , Zr0 ₂ or ZnO or mixtures of the metal oxides, or can be modified by R-Si0 _n , by hydrolysis of the corresponding metal alkoxides in an aqueous, organic or mixed solvents, optionally with the addition of dilute mineral acid, aqueous alkali, fluoride or tertiary amines as a hydrolysis catalyst. Ethanol, acetone or dioxane is preferably used as the organic solvent.

(b) Optional addition of dissolved or dispersed polymers to modify the layer properties, the proportion thereof with respect to the metal oxide sol being chosen so that the resulting modified metal oxide sol has a viscosity of at least 5 mPa / 20 ° C. The polymer content is typically in a range of 0.1 ... 20% by weight based on the metal oxide.

(c) dissolving the corrosion inhibitor in the optionally polymer-modified metal oxide sol. The inhibitor can also be mixed in before or during the hydrolytic formation of the metal oxide brine (1) if it is stable to the hydrolysis conditions (pH and solvent environment). For the use of inorganic inhibitors such as sodium nitrite, it is advisable to keep the proportion of organic solvents in the metal oxide sol low in order to avoid flocculation due to the limited solubility in organic solvents. This can be easily achieved, for example, by removing the organic solvent by distillation while adding the volume-equivalent amount of water. In this way, sufficiently stable, purely aqueous modified metal oxide sols are obtained which give homogeneous mixtures with the water-soluble inorganic corrosion inhibitors.

(d) gelling the inhibitor-containing metal oxide sol by heating or neutralizing to produce bulk products, for example to produce a powdery corrosion-inhibiting composite material, or by coating the metal oxide sol containing active substance on a carrier, for example on paper, cardboard, polymer films or foams, textile fabric or on metallic or metallized objects to be directly protected. The coating can be carried out by conventional coating techniques such as dipping ("dip coating"), spraying ("spray coating"), spinning ("spin coating"), brushing or watering. For the coating of foams, it is favorable to run the soaked foam through a roller mill before drying. Due to the roller spacing, the desired loading with the corrosion-inhibiting composite material can be easily adjusted.

(f) The solvent can be removed by conventional drying processes such as air, vacuum or freeze drying. The dry layer thicknesses are typically in a range of 0.08 ... 2 µm.

The corrosion-inhibiting composite materials thus obtained are easy to manufacture and have good long-term stability due to the known chemical inertness of the Matrix component (in the simplest case, pure silicon dioxide), excellent layering properties and an effective Immobilization with a high corrosion-inhibiting effect. The suitability for practically any inorganic is further advantage and organic substance classes, good adhesion to various Packaging materials and metallic objects as well as the possibility through the recipe and manufacturing technology the porosity of the composite material in wide Control borders.

The material according to the invention is therefore particularly suitable for Manufacture of anti-corrosive packaging materials, for coating metallic materials to be protected immediately and metallized objects as well as for corrosion protection in closed rooms by means of powdered corrosion inhibiting Composite materials.

Embodiments 1. Production of the metal oxide brine (a) Aqueous-alcoholic acidic SiO _2nd -Sol A

50 ml of tetraethoxysilane, 200 ml of ethanol and 100 ml of 0.01N hydrochloric acid are stirred for 20 hours at room temperature. A stable Si0 ₂ sol is obtained (4.2% solids content in 70% ethanol, pH about 4).

(b) Aqueous acidic Si0 _2nd -Sol B

200 ml of Sol A are mixed with 140 ml of water. The mixture is heated in a distillation apparatus on the boiling water bath and 140 ml of ethanol are distilled off. After cooling, a clear Si0 ₂ sol with 4.2% solids content in water (pH approx. 4) is obtained.

(c) Aqueous, dioxane-containing acidic SiO ₂ sol C

50 ml of tetraethoxysilane, 200 ml of dioxane and 100 ml of 0.01N hydrochloric acid are stirred for 20 hours at room temperature. A stable SiO ₂ sol is obtained (4.2% solids content in 70% dioxane, pH approx. 4).

(d) Aqueous-alcoholic alkaline Si0 ₂ sol D

50 ml of tetraethoxysilane, 200 ml of ethanol and 100 ml of 0.25% ammonia solution are stirred for 20 hours at room temperature. A stable Si0 ₂ sol is obtained (4.2% solids content in 70% ethanol, pH approx. 9).

(e) Aqueous-alcoholic acid sol E from Si0 ₂ / CH ₃ Si0 _1.5

35 ml of tetraethoxysilane, 15 ml of trimethoxymethylsilane are stirred in 200 ml of ethanol and 100 ml of 0.01 N hydrochloric acid for 20 hours at room temperature. A stable modified Si0 ₂ sol is obtained (4.2% solids content in 70% ethanol, pH approx. 4).

(f) Alcoholic sol F from Si0 ₂ -Ti0 ₂

1 g 1,1,1-tris (hydroxymethyl) propane in 10 ml ethanol, 10 ml Tetraethoxysilane and 3 ml 3-glycidyloxypropyltrimethoxysilane and with 2.2 g titanium tetraisopropylate in 30 ml abs. Mixed ethanol. 3 ml of 0.01N hydrochloric acid are added with stirring at room temperature slowly added dropwise in 10 ml of ethanol and stirred for 10 hours. Approx. 12% solids content in pure ethanol, pH approx. 4.

(g) Alcoholic polymer-modified Sol G Si0 ₂ -Ti0 ₂

100 ml Sol F (viscosity 4.5 mPa, 20 ° C) are stirred with 0.2 g Klucel H / Aqualon GmbH (hydroxypropyl cellulose) for 20 hours and filtered through a glass frit. The resulting Sol G has a viscosity of 48 mPa, 20 ° C. When coating a steel plate by dipping, a typical drawing speed of 30 cm / min with Sol F results in a dry layer thickness of 0.63 µm, with Sol G 2.82 µm.

(h) Aqueous alcoholic Sol H from Si0 ₂ -ZnO

80 ml of Sol F are mixed with 20 ml of 10% aqueous zinc acetate solution 10 Hours. Stable colorless sol, approx.11.5% solids.

2. Production of the corrosion-inhibiting composite materials.

The brine specified in Tab. 1 are mixed with the dissolved corrosion inhibitors and thus (a) different carriers are coated or (b) the mixture is gelled by neutralization with 2% ammonia solution and heating to 60 ° C. The solid gel is dried in air to remove the organic solvent and then in a vacuum desiccator to remove the residual moisture. Manufacture of corrosion inhibiting composite materials No. Sol (100 ml) Inhibitor Coating 1 A 20 ml dicyclohexylammonium nitrite (5% in 90% EtOH) Diving paper 2nd D " Diving paper 3rd B 50 ml NaN0 ₂ + subst. phenol (2% in 60% EtOH) Diving paper 4th H 20 ml hydroquinone + subst. phenol (2% in EtOH) Diving paper 5 H " Dip coating, steel 6 C. " PUR foam, dipping, rolling 7 F 50 ml 8-oxyquinoline + subst. Phenol ¹⁾ (2% in EtOH) Paint, paper 8th E " Paint, paper 9 E " Gell, dry mortars to powder 10th G 50 ml ascorbic acid + benzoquinone (2% in EtOH) Paint, paper

3. Testing the corrosion-inhibiting composite materials Sample No. 1 (see Table 1)

The VPI-containing paper produced according to the invention was in the Comparison to a commercially available reference system Corrosion protection paper (R1) according to the usual in practice Method for "testing the corrosion-protective effect of VPI packaging materials" (see "Packaging Review" 5/1988, p. 37 ff.) tested. (R1) contained the after chemical analysis Active ingredients dicyclohexylamine, sodium nitrite, sodium salt of caprylic acid, Urea and benzotriazole, the former two Substances in approximately the same proportion as dicyclohexylammonium nitrite in paper no. 1. Test specimens came from unalloyed Mass steel St-38 u2 for use. These were in accordance with regulations pretreated and alone or together with the testing VPI packaging in tightly sealed containers introduced and therein set conditions that a water condensation on the surface of the test specimen. The grinding surface of the test specimens was intended regularly visually for the existence of signs of corrosion examined.

The blank samples used without the use of VPI showed The first signs of corrosion in the Edge area; the test specimens exposed together with the R1 paper showed relatively even surface after approx. 11 d distributed rust spots. The manufactured according to the invention Paper no. 1 also guaranteed according to regulations after 21 d Full corrosion protection effect, recognizable by the perfect appearance of the corresponding test specimens.

Sample No. 2 (see Table 1)

VPI-containing paper produced according to the invention was also used like the PUR foam (POLYFORM ET PF 193, Polyform Kunststofftechnik GmbH Rinteln) on his Corrosion protection properties checked by cutting from it Segments together with sheets made of Al 99 or galvanic galvanized steel (Zn layer 8 µm) in closed glass vessels stored over saturated disodium hydrogen phosphate solution were. The latter sets in the closed gas space at 25 ° C a rel. Air humidity (RH) = 95% on. They had Segments of the VPI packaging means the same geometric Surface like the test sheets used and were in one 2 cm apart. The test sheets were immediately before the exposure in the test chamber with 0.01 M Saline has been smeared. In reference to the invention Packaging material became a for in the same way investigated these purposes commercial VPI paper (R2) that the active ingredients di- and triethanolamine, the Na salts of caprylic and Contained benzoic acid and benzotriazole.

While the Al sheets used as blank samples already after approx. 40 h the first whitish, punctiform efflorescence showed, the system (R2) guaranteed its protective function about 9 d. The tests with the VPI packaging materials according to the invention Paper and PUR foam were added after 32 d completely perfect appearance of the test sheets.

The galvanized sheets used as blank samples were first whitish excretions in the marginal areas after approx. 30 h to recognize. The use of (R2) delayed this effect beyond about 12 d. The experiments with the invention VPI packaging materials are already being tracked and about 40 d show no changes.

Sample No. 3 (see Table 1)

Sheets of dimensions (76 x 152 x 5) mm made of cast iron GGl 25, visible by sanding with 280 grit paper Contaminants that had been freed were closed in a Damp room with (RH) = 93% and 40 ° C without or with simultaneous installation of a bowl, the CPI-issuing Contains powder, deposited. In addition to the manufactured according to the invention Composite No. 3 became a commercial granulate (R3) investigated that according to chemical analysis the active ingredients dicyclohexylammonium molybdate, Contained sodium nitrite and benzotriazole.

The VPI-containing solids were applied in a wide-area dish finely divided with 1 g / 100 cm ³ wet room volume. In the pure moist air, the first spotty signs of rust were already visible on the cast iron plates after about 7 hours. The corrosion protection was maintained in the chamber loaded with the commercially available VPI granules for about 62 hours. The samples which, together with the VPI-emitting powder produced according to the invention, were exposed to the damp room climate, did not show any rust formation even after the tests were stopped after 20 days. According to the invention, both the novel combination of corrosion inhibitors used and the constitution of the composite containing the VPI, which ensures continuous discharge into the gas phase, are responsible for this.

Sample No. 4 (see Table 1)

The one available according to the manufacturing method No. 4 according to the invention Paper has been designed to preserve the Gloss behavior of anodized Al plates examined. For the The CLOSScomp / OPTRONIK measuring system was used to assess the gloss Berlin used. This takes from the respective reflection curve of the substrate the measured values maximum value P / dB (Peak height), maximum increase A / (dB / degree), full width at half maximum HW / Degree of the reflection curve and calculates the visual from it Degree of gloss Gt in%.

A loss of gloss caused by the first signs of corrosion is represented in lower values for P, A and Gt as well in an increase in HW.

Al plates with the output data P = 46.2 dB, A = 14.9 dB / Degrees, HW = 7.6 and Gt = 77.7% were unpacked or wrapped with a layer of VPI-emitting paper in a condensation-changing climate (KFW) exposed according to DIN 50017. As a reference system served a commercial VPI paper, which according to chemical Analysis of the active ingredients monoethanolamine, benzoic acid, Na benzoate, Contained urea and glycerin (R4).

In the case of the Al plates used as blank samples, after a Exposure of 3 d only Gt = 28.9% determined. After At that time the plates packed with (R4) still had one Gloss value of Gt = 74.5% with the invention manufactured paper packed plates Gt = 77.0%. After 16 d This value had exposure within the scope of the measurement error not changed while on the samples packed in (R4) only Gt = 33% was still measured. With this, the superiority of the paper treated according to the invention No. 4 for the purposes of Corrosion protection documented.

Sample No. 5 (see Table 1)

Sheets coated according to the invention were made from anodized Al with regard to their gloss behavior also with that in the example No. 4 measuring system characterized CLOSScomp. Across from the visual gloss level was on uncoated aluminum plates before the start of the experiment on average at Gt = 82% even by about 5 % higher. The as a reference system (R5) with a commercially available Alkyd resin clear coat produced by dry coating thicknesses of about 20 µm brought in comparison to the initial state only values of Gt at 68%. The coated and the uncoated panels were stored in a climatic cabinet in accordance with IEC 68-2-30 cyclically loaded with moist air. There is a 24th h cycle from the following stages: 6 h 25 ° C and (RH) = 98%, 3 h Heating phase from 25 to 55 ° C at (RH) = 95%, 9 h 55 ° C at (RH) 93% and 6 h cooling phase from 55 to 25 ° C at (RH) = 98%. A visual assessment of the surface condition is carried out after each cycle of the test panels.

After 4 cycles, the untreated aluminum sheets already appeared Spotting, which leads to locally differing Gt values led by 36%. There was a decrease in (R5) sheets the Gt values determined after 8 cycles, initially due to the swelling of organic matter associated with water absorption Coating. The Gt values of those coated according to the invention Al plates were still within the measurement error after 30 cycles unchanged.

Sample No. 6 (see Table 1)

Polished copper and brass plates Ms63 were used between the invention coated, equally sized panels Layered PUR foam and in foils made of pure polyethylene (100 µm) welded in. The samples packed in this way were the wet climate exposure described for No. 5 exposed according to IEC 68-2-30. In parallel, test specimens of the designated materials without VPI-emitting aids or together with a commercially available film material as Reference system (R6) packed in the climate cabinet. (R6) contained the active substances ammonium molybdate according to chemical analysis, Triethanolamine and benzotriazole.

The blank samples showed a slight darkening after 7 cycles their surface. For the test specimens packed in (R6) a similar spot formation occurred on the Cu after 12 cycles and on the ms after 16 cycles. Those with the manufactured according to the invention VPI-emitting packaging deposited plates saw completely when the tests were canceled after 31 cycles unchanged.

Sample No. 7 (see Table 1)

The corrosion protection function of the manufactured according to the invention VPI paper No. 7 was tested in the same way as for No. 1 described. A similar inhibitory effect resulted. That seems particularly remarkable. While it is with the CPI applied in No. 1 for many years known and used dicyclohexylammonium nitrite, that only works as stable in the way described Reservoir was fixed, was the use of 8-oxyquinoline as a VPI only through the fixation according to the invention on solid surfaces possible. This example shows that with the Production of corrosion-inhibiting composite materials according to the invention in addition to already proven active ingredients, substances which cannot be applied with the previous processing methods when new CPIs can be introduced. That was also with a number of others, not mentioned here as examples Active ingredients successfully tested.

Sample No. 8 (see Table 1)

Copper lamellas, the outside without electricity (chemical) with a are provided with a thin nickel layer Semiconductor industry even after long storage in a dry place Air remains bondable at room temperature. By aging of the primary oxide film present on the nickel surface in cooperation with the chemical residues still present there Nickel plating is generally not the case. With the reference system (R1) mentioned at no. 1 was not delayed this aging process. The chemically nickel-plated Lamels could be stored in this VPI paper on average after 5 days of storage can no longer be bonded. The slats were opposed immediately after the end of the nickel plating in a desiccator transferred, the bottom part with the manufactured according to the invention Powder No. 8 was filled, then the aging of the Ni primary oxide film remained inhibited and the lamellae could still d Storage can be bonded.

Claims (13)

Corrosion-inhibiting composite material consisting of a composite that contains a metal oxide gel and one or more Contains corrosion inhibitors. Composite material according to claim 1, which contains Si0 ₂ , Al ₂ 0 ₃ , Ti0 ₂ , Zr0 ₂ or ZnO or mixtures thereof as metal oxide gel. Composite material according to claim 1, in which 1 part by weight Si0 _{2 is} co-condensed with x parts by weight (0 <x <1) R-Si0 _n as the metal oxide gel, where R is an organic alkyl radical which may contain amino, hydroxyl or alkoxy groups, and n <2 is. Composite material according to claims 1-3, wherein the metal oxide gel is modified by an organic polymer, wherein 1 part by weight of metal oxide gel with x parts by weight (0 <x <1) of an organic polymer is modified. Composite material according to claim 4, in which as an organic Polymer cellulose derivatives, starch derivatives, polyalkylene glycols or their derivatives, homo- or copolymers on acrylate and Methacrylate base, polystyrene sulfonate, natural resins or mixtures of the polymers mentioned can be used. Composite material according to claim 1 to 5, in which as Corrosion inhibitor, for example substituted phenols, Hydroquinone and quinone derivatives, nitrites, organic acids, Salts of organic acids, aliphatic or aromatic amines, Contain amides, thiazoles, triazoles, imidazoles or mixtures thereof are. Corrosion protection material, which according to a composite material contains one of claims 1 to 6. Corrosion protection material according to claim 7, which consists of a Packaging carrier material consists of which is coated with the composite or is impregnated. Corrosion protection material according to claim 7, which consists of a solid filler material that contains the composite. Process for the production of a corrosion-inhibiting composite material, characterized by the following steps: (a) Production of a metal oxide sol which contains Si0 ₂ , Al ₂ 0 ₃ , Ti0 ₂ , Zr0 ₂ or ZnO or mixtures of the metal oxides or can be modified by R-Si0 _n by acid or base-catalyzed hydrolysis of the corresponding metal alkoxides in one aqueous, organic or mixed solvents, (b) dissolving the corrosion inhibitor in the metal oxide sol, (c) gelling the corrosion inhibitor-containing metal oxide sol by heating and / or neutralizing or by coating on a support, and (d) removing the solvent. The method of claim 10, wherein the metal oxide sol is in Step (a) or (b) a dissolved or dispersed polymer is added. The method of claim 10 or 11, wherein in step (c) as a carrier paper, cardboard, polymer films or foams, textile fabric or metallic or directly to be protected metallized objects are used. Use of a corrosion-inhibiting composite material according to claims 1 to 6 as a vapor phase inhibitor; for the production or impregnation of anti-corrosive packaging materials; for coating metallic and metallized Objects; or for corrosion protection.