Metal-plastic hybrid material having steel and / or zinc and / or alloys thereof as metal components

Abstract

The invention relates to a method for producing a metal-plastic hybrid material, in particular by using an acidic aqueous composition, the material comprises at least one substrate having at least one metal surface at least partially made of steel and / or zinc and / or alloys thereof and at least one thermoplastic material applied to the metal surface of the substrate; a metal-plastic hybrid material obtainable by such a process; the use of the acidic aqueous composition for adhering the substrate to the plastic; the metal-plastic hybrid material itself; and the use of the metal-plastic hybrid material as a component in the automotive or construction industry.

Description

[0001] The present invention relates to: a process for producing a metal-plastic hybrid material, in particular by using an acidic aqueous composition, said material comprising at least one substrate having at least one metal surface at least partially made of steel and / or zinc and / or alloys thereof and at least one thermoplastic material applied to said metal surface of the substrate; a metal-plastic hybrid material obtainable by this process; the use of a water-soluble polymer, preferably when present in the acidic aqueous composition, for adhering a substrate to a plastic; the metal-plastic hybrid material itself; and the use of the metal-plastic hybrid material as a component in the automotive or construction industry. Background Art

[0002] Metal-plastic hybrids are one of the solutions proposed to reduce the weight of parts used in the automotive industry, such as in structural parts or in other components such as covers of battery materials, elements of powertrains, control panels, etc. In order to obtain such parts and components, plastics and metals can be joined together in several ways to develop a bonding material with an ideal combination of the properties of both materials (metal and plastic). However, joining dissimilar materials such as metal and plastic is very challenging, not only because of the different chemical properties of the two materials and therefore their surfaces, but also due to the shrinkage of the plastic material (such as thermoplastic materials) resulting from the dissimilarity of the two materials, as observed, for example, during molding.

[0003] Conventionally, metals are bonded to thermoplastic materials using adhesives. However, the production of such products using adhesives not only increases the number of production steps, but also the adhesion strength may decrease over time or may not exhibit integration strength at high temperatures. Therefore, the application of such methods in technical fields such as the automotive industry is unsuitable - not taking into account the economic and ecological disadvantages associated therewith - because here a significant heat resistance is often required due to electrodeposition and painting processes.

[0004] However, it is very challenging to join galvanized steel, such as hot-dip galvanized steel (HDG), to thermoplastic materials without the use of adhesives. In contrast to aluminum materials, where controlled etching or anodizing methods have been used to inject plastic directly onto the metal surface, such methods cannot be applied to materials made of or containing galvanized steel, such as HDG. Plasma technology can be used for this purpose, but due to equipment and other constraints, the treated metal surface is in this case limited to only a small portion. In addition, the surface is activated for only a few hours, which also undesirably limits this method.

[0005] It is known to apply polymer plastic films to galvanized steel by lamination, in particular in the form of polymer-metal laminates or in the form of sandwich materials or sandwich structures, in which the polymer plastic is sandwiched between two metal substrates. Examples of sandwich structures and laminates are generally disclosed, for example, in WO 2016 / 83083 A1 and WO 2017 / 125261 A1 and in WO 2017 / 098060 A, WO 2017 / 098061 A1, US 2015 / 314563 A1 and US 2019 / 022797 A1: WO 2016 / 83083 A1 relates to a product comprising at least one first metal layer and at least one plastic layer, which are joined to each other over their entire area to form a metal / plastic composite material; and to a method for producing such a product, wherein the visible surface of the metal layer of the metal / plastic composite material has a coil coating. WO2017 / 125261 A1 discloses a method for producing a composite material having at least two layers of metal material and at least one layer of polymer matrix material arranged between the two layers. WO 2017 / 098060 A1 and WO 2017 / 098061 A1 relate to a method for producing a product, wherein a metal carrier designed as a sheet metal or plate covered with at least one prepreg having a heat-crosslinkable hard plastic matrix (having continuous fibers) is formed into the product by deep drawing, stretch deep drawing or roll forming after the hard plastic matrix of the prepreg is pre-crosslinked by heating. US2015 / 314563 A1 discloses a laminated core and a method for connecting sheet metal parts to form a laminated core, wherein the sheet metal parts are separated from a sheet metal strip having a curable polymer adhesive layer, and the sheet metal parts having adhesive-coated sides facing each other are arranged on top of each other and bonded under pressure to form a laminated core. US2019 / 022797 A1 relates to a method for producing a plastic-metal hybrid component, which is made of a metal surface of a metal substrate provided with an anti-corrosion layer, the anti-corrosion layer having a surface with undercuts applied by using a filler material. These undercuts are then at least partially filled with thermoplastic components in such a way that thermoplastic components engage in these undercuts, thereby forming a plastic-metal hybrid component.

[0006] As mentioned above, other sandwich structures are disclosed in WO 2018 / 145981 A1 and WO 2015 / 181004 A1: WO 2018 / 145981 A1 discloses a composite material comprising two metal sheets connected by a thermoplastic polymer film and an adhesion promoter layer arranged between the corresponding sheet and the film. The aqueous adhesion promoter composition for providing the layer comprises a polymer selected from maleic acid / polyacrylic acid copolymer and (modified) polyacrylic acid and a phosphate component. WO 2015 / 181004 A1 discloses a method for producing a sandwich structure, wherein the metal surface is contacted with an aqueous conversion composition particularly comprising zinc cations, phosphates and polyacrylic acid, and then the resulting coated dry metal surface is contacted with an organic polymer layer, and the desired sandwich structure is formed by compacting under pressure and / or temperature.

[0007] In order to provide polymer-metal laminates and the above-mentioned sandwich materials, it is usually necessary to use plastic materials, such as thermoplastic materials with relatively low melting temperatures, such as polyethylene (PE) or polyethylene terephthalate (PET). Therefore, conventional methods for manufacturing the above-mentioned products are limited by the necessary polymer characteristics and are, for example, generally not suitable for plastics and thermoplastic materials with high melting temperatures, such as, for example, polyamide 6 itself in pure form, which is not easy to process for these reasons.

[0008] Therefore, there is a need to provide a metal-plastic hybrid material and a method for producing the same, which material contains steel and / or zinc and / or alloys thereof as metal components, has excellent and permanent or at least durable adhesion properties as far as the adhesion between the metal and the plastic is concerned, but at the same time the material can be produced without the need to use conventional adhesives, the material further allows the use of a wider range of thermoplastic polymer materials than in conventional lamination methods for producing metal-plastic hybrid materials, in particular the material allows the use of thermoplastic materials with a melting temperature above 200° C., and the material can further be produced in a flexible, convenient and ecologically and economically advantageous manner.

[0009] question

[0010] It is therefore an object of the present invention to provide a metal-plastic hybrid material and a method for producing the same, which material contains steel and / or zinc and / or alloys thereof as metal components, has excellent and permanent or at least durable adhesion properties as far as the adhesion between the metal and the plastic is concerned, but at the same time the material can be produced without the need to use conventional adhesives, the material further allows the use of a wider range of thermoplastic polymer materials than in conventional lamination methods for the production of metal-plastic hybrid materials, in particular the material allows the use of thermoplastic materials with a melting temperature above 200° C., and the material can further be produced in a flexible, convenient and ecologically and economically advantageous manner.

[0011] Solution

[0012] This object has been solved by the subject matter of the claims of the present application and by its preferred embodiments disclosed in the present description, ie by the subject matter described herein.

[0013] A first subject of the present invention is a method for producing a metal-plastic hybrid material comprising a substrate having at least one metal surface and at least one thermoplastic material applied to the metal surface of the substrate, the method comprising at least steps 1) and 3) and optionally step 2), namely

[0014] 1) applying an aqueous acidic composition at least partially to at least one metal surface of a substrate to at least partially form a film on said surface,

[0015] wherein the metal surface is at least partially made of at least one steel and / or zinc and / or at least one alloy thereof, and

[0016] wherein the acidic aqueous composition comprises, in addition to water, at least one water-soluble polymer as at least one component a1), the at least one water-soluble polymer having at least one functional group selected from the group consisting of acid groups, hydroxyl groups, amino groups, and mixtures thereof,

[0017] and optionally drying or curing the film to form a dried or cured layer,

[0018] 2) optionally applying at least one thermoplastic polymer material TM1 at least partially in the form of a foil onto the film or onto the dried or cured layer obtained after step 1), and

[0019] 3) injecting at least one thermoplastic polymer material TM2 at least partially onto the film or the dried or solidified layer obtained after step 1) or onto the foil optionally obtained after step 2) to form a metal-plastic hybrid material, wherein the at least one thermoplastic polymer material TM2 is the same as or different from the thermoplastic material TM1 optionally applied in step 2) and is present in a molten state.

[0020] A further subject matter of the invention is a metal-plastic hybrid material obtainable by this method.

[0021] A further subject of the present invention is the use of a water-soluble polymer as defined above as component a1) of an acidic aqueous composition, preferably the use of said water-soluble polymer when present in said acidic aqueous composition as defined in conjunction with step 1) of the process for adhering a metal surface of a substrate at least partially made of steel and / or zinc and / or at least one alloy thereof to a thermoplastic material present on said surface in foil form (such as a foil at least partially made of at least one thermoplastic polymer material TM1) or applied to said surface by injection molding (such as a thermoplastic polymer material TM2).

[0022] A further subject of the invention is a metal-plastic hybrid material itself, i.e. a metal-plastic hybrid material comprising:

[0023] a substrate having at least one metallic surface, the at least one metallic surface being at least partially made of at least one steel and / or zinc and / or at least one alloy thereof,

[0024] a film or a dried or cured layer at least partially applied to said metal surface, obtainable by applying at least partially to said metal surface an aqueous acidic composition as defined in connection with step 1) of the method according to the invention,

[0025] optionally at least one thermoplastic polymer material TM1, which at least one thermoplastic polymer material TM1 is at least partially applied in foil form to the film or the dried or cured layer, preferably as defined in optional step 2) of the method of the invention, and

[0026] At least one thermoplastic polymer material TM2, which is in a form obtainable by injection molding and is at least partially applied to the film or to the dried or cured layer or (if present) to the foil, preferably as defined in step 3) of the method of the present invention, which material TM2 is the same as or different from the optionally present thermoplastic polymer material TM1, wherein the thermoplastic polymer material TM2 preferably comprises at least one polyamide.

[0027] A further subject matter of the present invention is the use of the metal-plastic hybrid material or the metal-plastic hybrid material obtainable by the process according to the invention as a component in the automotive or construction industry.

[0028] It has been found that the acidic aqueous composition used in the present invention is capable of providing a conversion coating on the metal surface of the substrate, and at the same time provides good adhesion between the metal surface and the thermoplastic material TM1 or TM2 applied on the metal surface due to the adhesion promoting properties of the formed conversion coating film or layer. It has been found that sufficient adhesion cannot be obtained without applying the acidic aqueous composition. It has been further found that the water-soluble polymer present in the acidic aqueous composition acts as an adhesion promoter in this regard. Achieving excellent adhesion is particularly relevant because it has been found that the strength of the adhesion layer between the metal surface and the thermoplastic material used has a significant impact on the life of the metal-plastic hybrid material. In addition, it has been found that all kinds of substrates with different shapes can be used, especially the surface of the substrate containing metal steel and / or zinc and / or at least one alloy thereof, especially the surface made of galvanized steel at least in part, of sheets, coils and / or other shapes.

[0029] Furthermore, it has been found, particularly surprisingly, that adhesion problems and problems known from the prior art when combining two different materials, namely, on the one hand, a thermoplastic polymer such as TM2 or TM1, and on the other hand, steel and / or zinc and / or at least one alloy thereof such as galvanized steel, in particular HDG, can be overcome by the process of the invention for producing a metal-plastic hybrid, in particular by the combination of step 3) (which allows the thermoplastic polymer TM2 to be injected directly onto the metal surface of the substrate or onto the foil-containing surface of the substrate) and chemical pretreatment of the metal surface using an acidic aqueous composition as shown in step 1) of the process of the invention before carrying out step 3). It has been found that the process for producing a metal-plastic hybrid allows in particular the use of even thermoplastic polymers such as TM2, such as polyamides, in particular polyamide 6, with a relatively high melting temperature, which are applied directly by injection molding according to step 3) of the process of the invention. Injecting a thermoplastic material directly onto a metal surface according to step 3) offers many advantages, among which simplicity, robustness and a wide application window. The flexibility of the method can be achieved, for example, in that step 1) of the method can be used in a coil production line by means of a roll coater or can be sprayed at a job coater, which makes the method highly flexible.

[0030] It has also been found that by applying the acidic aqueous composition used according to the invention, not only excellent adhesion but also very good corrosion protection is achieved.

[0031] It has furthermore surprisingly been found that the process according to the invention allows the direct thermoplastic injection of a thermoplastic polymer TM2 onto a metal surface containing steel and / or zinc and / or at least one alloy thereof, such as a surface made of galvanized steel, despite only a very short contact time between TM2 and the metal surface and despite a significant temperature difference between the molten thermoplastic polymer material TM2 (which may exceed 200° C.) and the substrate temperature of the surface (which is typically room temperature, i.e. in the range of 18 to 25° C., but can also be heated if necessary, e.g. up to 80° C.). It has been found that, in particular, the presence of functional groups of a water-soluble polymer in the acidic aqueous composition used allows very rapid bonding prior to cooling of the thermoplastic material after application / injection.

[0032] Furthermore, it has been found that chemical pretreatment of the metal surface using an acidic aqueous composition as shown in step 1) of the method of the present invention before carrying out step 3) also provides strong adhesion to the thermoplastic material TM1 (when applied as a foil (foil) to the treated metal surface). It has been found that the foil formed by applying TM1 can then be further used as an adhesion layer or interface layer (when carried out, the thermoplastic material TM2 is injected into the adhesion layer or interface layer in step 3) of the method), especially when the foil formed by TM1 in step 2) is chemically compatible with the material TM2 applied in step 3). DETAILED DESCRIPTION

[0033] In the sense of the present invention, the term "comprising", for example in connection with an acidic aqueous composition, preferably has the meaning of "consisting of". For example, with respect to the acidic aqueous composition, in addition to all mandatory components present therein, one or more further optional components as identified below may also be included therein. In each case, all components may be present in their preferred embodiments, as identified below.

[0034] The proportions and amounts given below in wt.-% (weight %) of any components present in the acidic aqueous composition add up to 100 wt.-%, based in each case on the total weight of the acidic aqueous composition.

[0035] Method of the present invention

[0036] A first subject of the invention is a method for producing a metal-plastic hybrid material comprising a substrate having at least one metal surface and at least one thermoplastic material applied to the metal surface of the substrate. The method comprises at least steps 1) and 3) and optionally step 2).

[0037] In addition to steps 1) and 3) and optional step 2), the method may also include further steps. For example, a cleaning step of the metal surface may be performed before step 1), for example by an acidic, alkaline or pH-neutral, preferably alkaline cleaning composition, wherein in the case of an acidic cleaning composition, the composition is different from the acidic aqueous composition used in step 1).

[0038] More specifically, before step 1), the following optional steps may be performed:

[0039] Step A-1): The surface of the substrate is preferably subjected to an alkaline cleaning and optionally subsequent rinsing.

[0040] Preferably, the process does not comprise any step involving any treatment with chromium ions, such as Cr(VI) and / or Cr(III) ions.

[0041] The optional rinsing as part of step A-1) is preferably performed by using deionized water or tap water. Preferably, rinsing is performed by using deionized water.

[0042] Substrate

[0043] The metal surface of the substrate is at least partially made of at least one steel and / or zinc and / or at least one alloy thereof. Preferably, the entire metal surface is at least partially made of at least one steel and / or zinc and / or at least one alloy thereof. The term "alloy" refers to both steel alloys and zinc alloys. More preferably, the substrate itself is a metal substrate at least partially made of at least one steel and / or zinc and / or at least one alloy thereof. Examples of steel are galvanized steel such as hot-dip galvanized steel (HDG) and at least one alloy of steel and zinc and / or magnesium. An example of a zinc alloy is a zinc-magnesium alloy. Preferably, the metal surface does not contain any amount of aluminum and / or aluminum alloy that exceeds the amount of at least one steel and / or zinc and / or at least one alloy thereof present therein.

[0044] All kinds of substrates with different shapes and geometries can be used.Preferably, the substrate is selected from sheets and coils and parts, in particular parts suitable for the automotive industry, and mixtures thereof.

[0045] Preferably, the metal-plastic hybrid material consists of a substrate having at least one metal surface at least partially made of steel and / or zinc and / or at least one alloy thereof and at least one thermoplastic material applied to the metal surface in step 3) and optionally step 2). In particular, the metal-plastic hybrid material preferably does not contain any further substrate having at least one metal surface. In particular, the metal-plastic hybrid material does not represent any sandwich structure in which the applied at least one thermoplastic material is sandwiched between two metal surfaces.

[0046] Steps of the method 1)

[0047] In step 1), an aqueous acidic composition is at least partially applied to at least one metal surface of a substrate to at least partially form a film on said surface. Optional drying or curing of the film to form a dried or cured layer may be carried out in step 1). Preferably, such drying or curing is carried out. Drying is preferably carried out, for example, at a temperature in the range of 15°C to 100°C, more preferably at a temperature in the range of 18°C ​​to 95°C, in particular at a temperature in the range of 20°C to 90°C.

[0048] Step 1) is preferably a contacting step, wherein the metal surface is contacted with the aqueous acidic composition. "Contacting" includes spraying, dipping or rolling procedures. "Contacting" can also be flooding of the surface or even manual wiping or brushing.

[0049] The treatment time, i.e. the period of time during which the surface is in contact with the acidic aqueous composition used in step 1), is preferably from 15 seconds to 20 minutes, more preferably from 30 seconds to 10 minutes, and most preferably from 45 seconds to 5 minutes, such as for example from 1 to 3 minutes, preferably in each case when parts, in particular parts suitable for the automotive industry, are used as substrates. In the case where the substrate is a coil, the treatment time is preferably less than 1 minute, more preferably less than 30 or 15 seconds, even more preferably less than 10 seconds, yet more preferably in the range of 1 to 5 seconds.

[0050] The temperature of the acidic aqueous composition used in step 1) is preferably 5 to 50°C, more preferably 15 to 45°C and most preferably 25 to 40°C.

[0051] By carrying out step 1), preferably, a conversion coating film is formed on the metal surface. Preferably, a coating is formed after drying or curing, preferably drying, which has a coating weight determined by XRF (X-ray fluorescence spectroscopy): 1 to 90 mg / m2 in the presence of component a7) as defined below in the acidic aqueous composition. 2 , more preferably 5 to 85 mg / m 2 , still more preferably 10 to 80 mg / m 2 , even more preferably 15 to 75 mg / m 2 Preferably, a coating is formed, preferably after drying or curing, preferably drying, which has a coating weight determined by XRF (X-ray fluorescence spectroscopy): in the presence of component a4) as defined below in the acidic aqueous composition, of 0.5 to 10 mg / m 2 , more preferably 1 to 8 mg / m 2 , still more preferably 1.5 to 7 mg / m 2 , even more preferably 2 to 6 mg / m 2of manganese, calculated in each case as metal.

[0052] Acidic aqueous composition

[0053] The acidic aqueous composition comprises, in addition to water, as at least one component a1), at least one water-soluble polymer having at least one functional group selected from the group consisting of acid groups, hydroxyl groups, amino groups, and mixtures thereof. All components present in the composition are different from one another.

[0054] Preferably, the acidic aqueous composition used in step 1) has a pH value in the range of 0.1 to <7.0, more preferably 0.5 to 6.5, still more preferably 0.7 to 6.0, even more preferably 0.9 to 5.5, still more preferably 1.0 to 5.0, yet more preferably 1.2 to 4.5, still more preferably 1.5 to 4.0, even more preferably 1.7 to 3.5, most preferably 1.8 to 3.0. Preferably, the pH value is measured at room temperature (23°C). If necessary, the pH can preferably be adjusted by using phosphoric acid, ammonia and / or sodium carbonate. Most preferably, the pH value is in the range of 2.0 ± 0.5.

[0055] In the sense of the present invention, the term "aqueous" with respect to the acidic aqueous composition used in step 1) preferably means that the composition is a composition which contains at least 50 wt.-%, preferably at least 60 wt.-%, more preferably at least 70 wt.-%, in particular at least 80 wt.-%, most preferably at least 90 wt.-% of water, based on its total content of organic and inorganic solvents including water. Thus, the composition may contain at least one organic solvent other than water, however, in an amount lower than the amount of water present.

[0056] Preferably, the acidic aqueous composition used in step 1) contains at least 50 wt.-%, preferably at least 60 wt.-%, more preferably at least 70 wt.-%, in particular at least 80 wt.-%, most preferably at least 90 wt.-% of water, in each case based on its total weight.

[0057] The acidic aqueous composition can be used as a dipping bath. However, it can also be applied by nearly any conventional coating procedure as outlined above in connection with step 1), like for example spraying, rolling, brushing, wiping, etc. Spraying or rolling is preferred.

[0058] The acidic aqueous composition used in step 1) is preferably a solution.

[0059] Preferably, the acidic aqueous composition used in step 1) has a temperature in the range of 18 to 35°C, more preferably 20 to 35°C, especially 20 to 30°C.

[0060] Water-soluble polymer (component a1)

[0061] The acidic aqueous composition comprises, as at least one component a1), at least one water-soluble polymer having at least one functional group selected from the group consisting of an acid group, a hydroxyl group, an amino group, and mixtures thereof.

[0062] The solubility is determined at a temperature of 20° C. and atmospheric pressure (1.013 bar).

[0063] Preferably, the at least one water-soluble polymer used as component a1) is present in the acidic aqueous composition in an amount ranging from 0.1 to 5.0 g / L, more preferably from 0.3 to 4.5 g / L, even more preferably from 0.5 to 4.0 g / L, still more preferably from 0.7 to 3.5 g / L, yet more preferably from 0.9 to 3.0 g / L, still more preferably from 1.1 to 2.5 g / L, most preferably from 1.3 to 2.0 g / L. Alternatively, the at least one water-soluble polymer used as component a1) is present in the acidic aqueous composition in an amount ranging from 0.1 to 15.0 g / L, more preferably from 0.3 to 12.0 g / L, even more preferably from 0.5 to 11.0 g / L, still more preferably from 0.7 to 10.0 g / L.

[0064] Preferably, at least one water-soluble film-forming polymer used as component a1) has at least one functional group selected from carboxylic acid groups, phosphonic acid groups, sulfonic acid groups, hydroxyl groups, amino groups, and mixtures thereof, more preferably selected from carboxylic acid groups, hydroxyl groups, amino groups, and mixtures thereof, even more preferably selected from carboxylic acid groups.

[0065] Preferably, the at least one water-soluble polymer used as component a1) is a homopolymer or copolymer obtainable by polymerization of at least one ethylenically unsaturated monomer, at least one part of which carries at least one functional group selected from acid groups, hydroxyl groups, amino groups, and mixtures thereof; more preferably a homopolymer or copolymer obtainable by polymerization of at least one vinyl monomer and / or (meth)acrylic monomer, at least one part of which carries at least one functional group selected from acid groups, hydroxyl groups, amino groups, and mixtures thereof. In particular, in the case of homopolymers and copolymers of vinylphenol, these polymers can be modified with compounds carrying amino groups, such as ethanolamine and / or N-methylglucamine, via a condensation reaction, in particular a Mannich reaction.

[0066] The example of the monomer that comprises acid group is acrylic acid and methacrylic acid and maleic acid.The example of the monomer that comprises hydroxyl group is 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, (meth) 3-phenoxy-2-hydroxypropyl acrylate, mono(meth) glyceryl acrylate, N-(2-hydroxypropyl) (meth) acrylamide, allyl alcohol, hydroxystyrene, hydroxyalkyl vinyl ether such as hydroxybutyl vinyl ether and vinyl benzyl alcohol, vinyl phenol and vinyl alcohol.Can use additionally and especially do not have the example of other non-functional monomer of acid group, hydroxyl group and mixture thereof is ethylene, propylene, butylene and aliphatic C1-C1 30 - (Meth)acrylic esters of monohydric alcohols, for example methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 3-propylheptyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. However, non-functional vinyl monomers are preferred, in particular over aliphatic C1-C1 30 - Non-functional (meth)acrylates of monohydric alcohols.

[0067] If the polymer a1) is a homopolymer, it is preferably a poly(meth)acrylic acid. If the polymer a1) is a copolymer and carries at least acid groups as functional groups, it is preferably a (meth)acrylic copolymer, which preferably comprises a polymer backbone and at least one side chain attached to the polymer backbone, which side chains carry acid groups, such as carboxylic acid groups.

[0068] The term "(meth)acryloyl" means "acryloyl" and / or "methacryloyl". Similarly, "(meth)acrylate" means acrylate and / or methacrylate, and "(meth)acrylic" means acrylic and methacrylic. "(Meth)acrylic polymers" are at least partly formed from "acrylic monomers" and / or "methacrylic monomers", but in case the polymer a1) is a copolymer, it may additionally contain non-acryloyl and non-methacryloyl monomer units if other ethylenically unsaturated monomers such as vinyl monomers are additionally used. Preferably, the main chain of such a (meth)acrylic copolymer is formed from more than 50 mol-%, even more preferably more than 75 mol-% of (meth)acrylic monomers.

[0069] Preferably, the at least one water-soluble polymer used as component a1) is selected from

[0070] (Meth)acrylic acid homopolymers, in particular acrylic acid homopolymers,

[0071] copolymers of (meth)acrylic acid and at least one ethylenically unsaturated monomer different from (meth)acrylic acid, in particular copolymers of (meth)acrylic acid and maleic acid,

[0072] copolymers of maleic acid and at least one ethylenically unsaturated monomer different from maleic acid, in particular copolymers of maleic acid and ethylene and / or propylene and / or at least one alkyl vinyl ether such as methyl vinyl ether,

[0073] copolymers of vinylphosphonic acid and at least one ethylenically unsaturated monomer different from vinylphosphonic acid, in particular copolymers of (meth)acrylic acid and vinylphosphonic acid and copolymers of (meth)acrylic acid and vinylphosphonic acid and maleic acid,

[0074] Vinyl alcohol homopolymer,

[0075] a copolymer of vinyl alcohol and at least one ethylenically unsaturated monomer different from vinyl alcohol, such as vinyl acetate,

[0076] Vinylphenol homopolymer,

[0077] a copolymer of vinylphenol and at least one ethylenically unsaturated monomer different from vinylphenol,

[0078] a copolymer of vinylmercaptoethanol and at least one ethylenically unsaturated monomer different from vinylmercaptoethanol, and

[0079] Homopolymers and copolymers of vinylphenol which have been modified with at least one amine, preferably at least one primary amine such as N-ethanolamine and / or N-methylglucamine, and mixtures thereof. The modification is preferably carried out via a Mannich base reaction based on the condensation of formaldehyde with primary or secondary amines.

[0080] More preferably, the at least one water-soluble polymer used as component a1) is selected from (meth)acrylic acid homopolymers, in particular acrylic acid homopolymers; copolymers of (meth)acrylic acid and at least one ethylenically unsaturated monomer different from (meth)acrylic acid, in particular copolymers of (meth)acrylic acid and maleic acid; copolymers of maleic acid and at least one ethylenically unsaturated monomer different from maleic acid, in particular copolymers of maleic acid and ethylene and / or propylene and / or at least one alkyl vinyl ether such as methyl vinyl ether; homopolymers of vinyl alcohol; copolymers of vinyl alcohol and at least one ethylenically unsaturated monomer different from vinyl alcohol; homopolymers and copolymers of vinylphenol which have been modified with at least one amine, preferably at least one primary or secondary amine, such as N-ethanolamine and / or N-methylglucamine; and mixtures thereof. Particularly preferred polymers are N-methylglucamine modified poly(vinylphenol), N-ethanolamine modified poly(vinylphenol), poly(maleic acid-co-vinyl methyl ether), poly(maleic acid-co-acrylic acid), polyacrylic acid, poly(vinyl-phosphonic acid-co-acrylic acid), poly(acrylic acid-co-maleic acid-co-vinylphosphonic acid), poly(acrylic acid-co-vinyl mercaptoethanol), poly(acrylic acid-co-maleic acid-co-vinyl mercaptoethanol) and mixtures thereof.

[0081] Preferably, the at least one water-soluble polymer has a weight average molecular weight (M) in the range of 1 000 to 350 000 g / mol, preferably 2 000 to 325 000 g / mol, more preferably 3 000 to 300 000 g / mol, still more preferably 4 000 to 375 000 g / mol. w ). The weight average molecular weight was determined by the method described below in the "Methods" section.

[0082] If a polymer a1) is used, this polymer a1) is a poly(meth)acrylic acid, in particular polyacrylic acid, which preferably has a weight average molecular weight (M) in the range of 10 000 to 350 000 g / mol, preferably 50 000 to 325 000 g / mol, more preferably 100 000 to 300 000 g / mol, still more preferably 150 000 or 200 000 to 375 000 g / mol. w If a polymer a1) is used which is a copolymer prepared at least partly from maleic acid, it preferably has a weight average molecular weight (M) in the range of 10 000 to 200 000 g / mol, preferably 15 000 to 150 000 g / mol, more preferably 20 000 to 100 000 g / mol, still more preferably 30 000 to 80 000 g / mol. wIf a polymer a1) is used which is a homopolymer or copolymer prepared at least partly from vinyl alcohol and / or vinyl phenol, it preferably has a weight average molecular weight (M) in the range of 500 to 100 000 g / mol, preferably 750 to 50 000 g / mol, more preferably 1 000 to 25 000 g / mol, even more preferably 1 000 to 10 000 g / mol. w ).

[0083] Optional component a2)

[0084] Preferably, the aqueous acidic composition used in step 1) further comprises zinc cations as at least one component a2), preferably in an amount in the range of 0 to 8.0 g / L, more preferably 0.1 to 8.0 g / L, even more preferably 0.2 to 6.0 g / L, still more preferably 0.3 to 5.0 g / L, yet more preferably 0.5 to 3.0 g / L, in each case calculated as metal. Alternatively, the at least one component a2) is present in the acidic aqueous composition in an amount in the range of 0.1 to 50.0 g / L, more preferably 0.3 to 45.0 g / L, even more preferably 0.5 to 40.0 g / L, yet more preferably 0.7 to 35.0 g / L.

[0085] The aqueous acidic composition may comprise additional components as listed hereinafter. In view of the ingredients of the aqueous composition, as used herein throughout the specification, the term "further comprises" means "in addition to the mandatory components". Thus, such "additional" components include ions other than the metal ions mentioned above.

[0086] Preferably,

[0087] (i) The aqueous acidic composition used in step 1) further comprises at least one of components a3) and a4), preferably both a3) and a4) or only a4), namely

[0088] as at least one component a3), at least one metal cation selected from the group of titanium ions, zirconium ions and hafnium ions, and mixtures thereof, preferably at least one metal cation selected from the group of titanium ions and zirconium ions and mixtures thereof, preferably in an amount in the range of 5 to 5000 ppm, more preferably 7.5 to 4000 ppm, still more preferably 10 to 3000 ppm, even more preferably 12.5 to 2000 ppm, yet more preferably 15 to 1000 ppm, in particular 17.5 to 500 ppm, more particularly 20 to 300 ppm, most preferably 30 to 200 ppm, in each case calculated as metal,

[0089] and / or

[0090] as at least one component a4) manganese cation, preferably in an amount in the range of 0 to 5.0 g / L or 0.1 to 5.0 g / L, more preferably 0.1 to 4.0 g / L, even more preferably 0.2 to 3.5 g / L, still more preferably 0.3 to 3.0 g / L, yet more preferably 0.5 to 2.5 g / L, in each case calculated as metal, or preferably in an amount in the range of 0 to 30.0 g / L or 0.1 to 27.5 g / L, more preferably 0.1 to 25.0 g / L, even more preferably 0.2 to 22.5 g / L, in each case calculated as metal,

[0091] and optionally further comprises

[0092] free fluoride anions as at least one optional component a5),

[0093] and / or

[0094] At least one organosilane is present as optional component a6), preferably in an amount in the range of 10 to 200 ppm.

[0095] or characterized by

[0096] (ii) the aqueous acidic composition used in step 1) further comprises, preferably in combination with a2), at least component a7), namely

[0097] As at least one component a7), phosphate anion is preferably in an amount in the range of 1 to 150 g / L, more preferably 2.0 to 125 g / L, even more preferably 3.0 to 100 g / L, still more preferably 4.0 to 95 g / L, yet more preferably 5.0 or 7.5 to 90 g / L, in each case calculated as PO, or preferably in an amount in the range of 1 to 200 g / L, more preferably 2.0 to 195 g / L, even more preferably 3.0 to 190 g / L, still more preferably 4.0 to 185 g / L, yet more preferably 5.0 or 7.5 to 180 g / L, in each case calculated as PO,

[0098] and optionally further comprises

[0099] as at least one component a4) manganese cation, preferably in an amount in the range of 0 to 5.0 g / L or 0.1 to 5.0 g / L, more preferably 0.1 to 4.0 g / L, even more preferably 0.2 to 3.5 g / L, still more preferably 0.3 to 3.0 g / L, yet more preferably 0.5 to 2.5 g / L, in each case calculated as metal, or preferably in an amount in the range of 0 to 30.0 g / L or 0.1 to 27.5 g / L, more preferably 0.1 to 25.0 g / L, even more preferably 0.2 to 22.5 g / L, in each case calculated as metal,

[0100] wherein in case (i), preferably no phosphate anion a7) is present, and

[0101] In the case of (ii), the acidic aqueous composition preferably contains no or essentially no free fluoride anions a5).

[0102] Most preferred are aqueous acidic compositions according to option (ii) which additionally comprise at least one component a2) (zinc cation).

[0103] In the case of option (i), the aqueous acidic composition used in step 1) preferably comprises at least one component a3), which is preferably selected from titanium ions and zirconium ions and mixtures thereof, most preferably selected from titanium ions. The content of component a3) can be monitored and determined by ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy). The method is described in detail below. Preferably, a precursor metal compound is used to generate the metal cation present as component a3) in the composition. Preferably, the precursor metal compound is water-soluble. The solubility is determined at a temperature of 20° C. and atmospheric pressure (1.013 bar). Particularly preferred zirconium compounds, titanium compounds and / or hafnium compounds are complex fluorides of these metals. The term "complex fluoride" includes monoprotonated and multiprotonated forms as well as deprotonated forms. Mixtures of such complex fluorides can also be used. In the sense of the present invention, complex fluorides are complexes of zirconium, titanium and / or hafnium with fluoride ions in the composition, for example by coordination of fluoride anions to zirconium, titanium and / or hafnium cations in the presence of water. Furthermore, it is also possible to use carbonates and / or complex carbonates and / or lactates and / or in particular nitrates of zirconium, titanium and / or hafnium. Preferably, however, these cations are incorporated into the composition in the form of their complex fluorides.

[0104] In the case of option (i), the aqueous acidic composition used in step 1) preferably contains manganese cations as a4). In this case, manganese can be added as metal, for example to phosphoric acid, and a diluted form thereof containing manganese cations a4) (and phosphate anions a7)) can be included in the composition. In the case of option (ii), the presence of manganese cations a4) is also possible.

[0105] In the case of option (i), the aqueous acidic composition used in step 1) optionally and preferably contains free fluoride anions as at least one component a5). These can result from the presence of component a3), i.e., in particular when complex fluorides of Ti, Zr and / or Hf are present in the composition, but can also or alternatively result from the presence of other optional components as described below, such as by incorporating at least one water-soluble fluorine compound. Examples of such water-soluble fluorine compounds are fluorides (except complex fluorides of Ti, Zr and / or Hf) and hydrofluoric acid. The free fluoride content is determined by a fluoride-sensitive electrode according to the method disclosed in the "Method" section.

[0106] Optionally, in the case of option (i), the acidic aqueous composition used in step 1) further comprises at least one organosilane as optional component a6). Examples are, for example, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, (3-mercaptopropyl)triethoxysilane, (3-glycidoxypropyl)trimethoxysilane and / or (3-glycidoxypropyl)triethoxysilane, and / or vinyltrimethoxysilane.

[0107] In the case of option (ii), the aqueous acidic composition used in step 1) preferably comprises, preferably in combination with a2), at least one component a7), namely phosphate anions as at least one component a7). By using phosphate anions, an amorphous zinc phosphate layer can be formed on the metal surface. The phosphate anions are preferably added in the form of phosphoric acid.

[0108] Additional optional components

[0109] Optionally, the aqueous acidic composition further comprises at least one metal cation selected from the following group: cations of metals of the 1st to 3rd subgroups (copper, zinc and scandium) and the 5th to 8th subgroups (vanadium, chromium, manganese, iron, cobalt and nickel) of the periodic table (including lanthanides) and the 2nd main group (alkaline earth metal group) of the periodic table, lithium, bismuth and tin. However, preferably, metal cations of the chromium, cobalt and nickel groups are not used. The above-mentioned metal cations are usually introduced in the form of their water-soluble compounds, preferably as their water-soluble salts. Preferred cations are selected from the group consisting of: cations of cerium and other lanthanides, iron, calcium, copper, magnesium, niobium, tantalum, yttrium, vanadium, lithium, bismuth and tin.

[0110] Optionally, the aqueous acidic composition further comprises at least one pH adjusting substance, which is preferably selected from the group consisting of nitric acid, sulfuric acid, methanesulfonic acid, acetic acid, aqueous ammonia, sodium hydroxide and sodium carbonate, wherein nitric acid, aqueous ammonia and sodium carbonate are preferred. Depending on the pH of the acidic aqueous composition, the above compounds can be in their fully or partially deprotonated form or in a protonated form.

[0111] Optionally, the aqueous acidic composition further comprises at least one complexing agent. An example is 1-hydroxyethane-1,1-diphosphonic acid (HEDP).

[0112] Optionally, the aqueous acidic composition further comprises at least one corrosion inhibitor. Examples are L-cysteine ​​and other amino acids, benzotriazole and mixtures thereof. Preferably, the at least one corrosion inhibitor does not contain any kind of metal ions.

[0113] Optionally, the aqueous composition further comprises at least one organic acid, preferably at least one organic acid having at least two carboxylic acid groups and / or at least one organic acid having at least one carboxylic acid group and at least one further functional group having at least one donor atom (such as an OH-group) (e.g. lactic acid), in particular when the aqueous composition is alkaline. The presence of such compounds can contribute to the stabilization of at least one metal ion (such as a Zr cation) in the composition.

[0114] The aqueous composition may further comprise at least one of the following components: one or more waxes, one or more wetting agents, and one or more defoaming agents.

[0115] Optional step 1a)

[0116] After step 1), the surface of the substrate obtained after the contacting according to step 1) may optionally be rinsed, preferably with deionized water or tap water (optional step 1a)). If this step is performed, it is preferably done before any drying or curing performed in step 1).

[0117] Optional step 2) of the method and step 3) of the method

[0118] In optional step 2), at least one thermoplastic polymer material TM1 is at least partially applied in the form of a foil onto the film or the dried or cured layer obtained after step 1) (or after optional step 1a)).

[0119] The formed foil obtained by using the thermoplastic polymer material TM1 in optional step 2) is preferably used as a compatibilizer material for the thermoplastic polymer material TM2 optionally subsequently injected in step 3). Preferably, optional step 2) is not performed by injection molding. Preferably, the foil made of at least one thermoplastic polymer material TM1 is at least partially applied to the film or to the dried or cured layer obtained after step 1) (or after optional step 1a).

[0120] Preferably, optional step 2) is not performed. If optional step 2) is performed, the thermoplastic polymer material TM1 is preferably different from the thermoplastic polymer material TM2.

[0121] In step 3), at least one thermoplastic polymer material TM2 is at least partially applied to the film or the dried or cured layer obtained after step 1) or the foil optionally obtained after step 2) to form a metal-plastic hybrid material, and the at least one thermoplastic polymer material TM2 is the same as or different from the thermoplastic material TM1 optionally applied in step 2) and is present in a molten state.

[0122] Step 3) is an injection molding step, wherein the thermoplastic polymer material TM2 is preferably injected directly onto the metal surface of the substrate, onto which the acidic aqueous composition has been previously applied in step 1).

[0123] Optional step 2) and / or step 3) may be performed in a continuous or discontinuous manner.

[0124] The substrate obtained after step 1) or after optional step 1a) is preferably heated before carrying out optional step 2) or before carrying out step 3), preferably to a temperature above the melting temperature of the respective thermoplastic material used.

[0125] Preferably, the thermoplastic polymer material TM1 used in optional step 2) and / or the thermoplastic polymer material TM2 used in step 3) are applied in such a way that a vacuum is applied to bring the corresponding thermoplastic polymer material into contact with at least a portion of the substrate, but preferably with the entire surface of the substrate (which surface has been in contact with the acidic aqueous composition in step 1)), and remove the air enclosed between the surface of the substrate and the corresponding thermoplastic polymer material. Preferably, the temperature of the substrate and the corresponding thermoplastic polymer material applied thereto is kept above a temperature that promotes the connection of the applied thermoplastic polymer material to the metal substrate. After the above-mentioned heating, the substrate is preferably placed in a device in which the corresponding thermoplastic polymer material can be placed on the surface of the substrate, preferably a thermoforming device: for example, wherein the thermoplastic polymer material TM1 can be applied as a foil. As an alternative, it is also possible to first place the substrate into the device, in which the corresponding thermoplastic polymer material is applied and then heat the substrate before the corresponding thermoplastic polymer material is placed thereon. Preferably, after the heated substrate has been placed in the device or after the substrate has been placed in the device and then heated, the corresponding thermoplastic polymer material is placed on the substrate and optionally heated, as in the case of step 3), wherein the material is injected in the molten state. If the corresponding thermoplastic polymer material is heated, the heating can be performed, for example, by infrared radiation.

[0126] The temperature to which the respective thermoplastic polymer material is heated is preferably selected such that the thermoplastic material is rubber-elastic. For this purpose, the thermoplastic material is preferably heated to a temperature above the glass transition temperature of the thermoplastic material (if the thermoplastic material is an amorphous thermoplastic), or above the crystallite melting temperature (if the thermoplastic material is a semi-crystalline thermoplastic), but preferably below the melting temperature to avoid any damage. After placing the respective thermoplastic polymer material on the surface of the substrate and optionally after having heated the material, a vacuum is preferably applied as described above.

[0127] By applying vacuum, the corresponding thermoplastic polymer material is preferably attached to the surface of the substrate and a strong connection can be achieved. Removing the air that may be enclosed between the surface of the substrate and the corresponding thermoplastic polymer material preferably produces a smooth surface without bubbles. In order to apply vacuum, the substrate may include openings through which air can be extracted. If the substrate should not have any openings, the air between the substrate and the corresponding thermoplastic polymer material can also be extracted at the edge of the thermoplastic polymer material. If air is extracted at the edge, it is preferred that air is extracted at least on two opposite sides and preferably on the entire circular edge of the corresponding thermoplastic polymer material. In order to apply vacuum, any suitable vacuum pump can be used. If air is extracted at the edge of the corresponding thermoplastic polymer material, the corresponding thermoplastic polymer material is preferably fixed in a device for applying vacuum so that a gap is formed between the substrate and the edge of the corresponding thermoplastic polymer material and a vacuum is applied through the gap. By applying vacuum, the corresponding thermoplastic polymer material preferably contacts the substrate uniformly over the entire surface of the substrate, and therefore forms a uniform layer on the surface of the substrate.

[0128] After the corresponding thermoplastic polymer material is preferably brought into contact with the entire surface of the substrate, the temperature of the substrate and the corresponding thermoplastic polymer material is preferably maintained at a temperature that promotes the connection of the thermoplastic material to the substrate, preferably at a temperature above the melting temperature of the thermoplastic material. By maintaining this temperature, the thermoplastic material preferably chemically reacts at least with the functional groups of the water-soluble polymer initially present in the acidic aqueous composition, thereby achieving a stable connection between the surface of the substrate and the corresponding thermoplastic polymer material and forming a composite part comprising a "metal layer" (metal surface of the substrate) and a "polymer layer" (applied thermoplastic material).

[0129] Preferably, at least before carrying out step 3), the substrate obtained after step 1), optionally 1a) or optionally step 2) is placed in a mold before carrying out step 3).

[0130] Thermoplastic polymer materials TM1 and TM2

[0131] The thermoplastic polymer material TM2 may be the same as or different from the thermoplastic material TM1, preferably different therefrom.

[0132] Preferably, each of the thermoplastic polymer materials TM1 and TM2 is capable of chemically bonding to the functional groups of the water-soluble polymer initially present in the acidic aqueous composition used in step 1).

[0133] Preferably, the thermoplastic polymer material TM2 is selected from polyamides, polyesters such as PET and / or PBT, polyurethanes, polycarbonates, polyolefins such as polypropylene and polyethylene, and mixtures thereof. Recycled thermoplastic polymer materials such as recycled polyamides can be used. Most preferred are polyamides. Preferably, the polyamides are selected from PA6, PA66, PA66 / 6, PA6.10, PA6.12, PA12, PA9T, PA6I / 6T, PA6T / 6I, PA6 / 6.36 and combinations thereof. Preferably, at least one polyamide is applied via step 3) as at least one thermoplastic polymer material TM2.

[0134] Thermoplastic polymer materials TM1 and / or TM2, preferably TM2, such as polyamide in a form in which they have been compounded with at least one additive, such as at least one rubber, such as EPDM (ethylene propylene diene monomer) rubber, in particular to improve the properties of the thermoplastic polymer material, such as to reduce its water absorption. Alternatively or additionally, the thermoplastic polymer material TM1 and / or TM2, preferably TM2, may optionally contain (i) at least one fiber, such as glass fiber, carbon fiber, aramid fiber and combinations thereof, and / or may optionally contain (ii) polyether block polyamide, such as polyether diamine with aliphatic C4 to C 40 dicarboxylic acids and / or C6 to C 12 Copolymers of lactams such as caprolactam or lauryl lactam, aliphatic C4 to C 10 Diamine and aliphatic C4 to C 40 Copolymer products of dicarboxylic acids, C6 to C 12 Polycondensation products of lactams, copolymerization products of lactams and / or aliphatic dicarboxylic acids with aliphatic diamines, and combinations thereof, and / or may optionally contain (iii) at least one impact modifier, such as maleic anhydride grafted copolymers of ethylene with at least one of an α-olefin, a (meth)acrylate and (meth)acrylic acid, copolymers of maleic anhydride with at least one of ethylene and (meth)acrylate, styrene maleic anhydride or maleic anhydride grafted polypropylene.

[0135] Preferably, the thermoplastic polymer material TM1 is selected from polyamides, polyesters such as PET and / or PBT, polyurethanes, polycarbonates, polyolefins such as polypropylene and polyethylene, and mixtures thereof. Recycled thermoplastic polymer materials such as recycled polyamides can be used. Preferably, the polyamide is selected from PA6, PA66, PA66 / 6, PA6.10, PA6.12, PA12, PA9T, PA6I / 6T, PA6T / 6I, PA6 / 6.36 and combinations thereof. Most preferred are polyolefins. Preferably, at least one polyolefin is applied as at least one thermoplastic polymer material TM1 via optional step 2).

[0136] Preferably, the thermoplastic polymer material TM1 has a melting temperature in the range of 80 to 280° C. For example, a polyolefin may have a melting temperature of 80° C., whereas a polyamide has a significantly higher melting temperature of, for example, 280° C.

[0137] Preferably, the thermoplastic polymer material TM2 has a melting temperature in the range as defined for the thermoplastic polymer material TM1.

[0138] Metal-plastic hybrid material obtainable by the method of the present invention

[0139] A further subject matter of the present invention is a metal-plastic hybrid material obtainable by the process according to the invention.

[0140] All preferred embodiments described above in conjunction with the method according to the invention and its preferred embodiments are also preferred embodiments of the metal-plastic hybrid material according to the invention obtainable by said method.

[0141] Preferably, the metal-plastic hybrid material does not have a sandwich structure in which the metal surface of the substrate, preferably the substrate itself, is sandwiched between two thermoplastic materials. Therefore, preferably, the method of the present invention does not include any step in which any thermoplastic polymer material is applied to the metal surface of the substrate opposite to the metal surface (to which the thermoplastic polymer material TM2 has been applied in step 3), in particular not in the form of a foil.

[0142] Preferably, the dry layer thickness of the layer obtained by drying or curing the film obtainable by at least partially applying the aqueous acidic composition as defined in connection with step 1) of the process according to the invention as described above to the metal surface is in the range of 100 to 1000 nm, more preferably 150 to 750 nm, in particular 250 to 550 nm.

[0143] Use of water-soluble polymers and acidic aqueous compositions

[0144] A further subject of the present invention is the use of a water-soluble polymer as defined above as component a1) of an acidic aqueous composition, preferably the use of said water-soluble polymer when present in said acidic aqueous composition as defined in conjunction with step 1) of the above-described inventive method for adhering a metallic surface of a substrate at least partially made of steel and / or zinc and / or at least one alloy thereof to a thermoplastic polymer material present on said surface in the form of a foil or applied to said surface by injection molding, preferably by using the inventive method.

[0145] All preferred embodiments described above in conjunction with the inventive method, the inventive metal-plastic hybrid material obtainable by said method, and preferred embodiments thereof are also preferred embodiments of the inventive use.

[0146] Metal-Plastic Hybrid Materials

[0147] A further subject of the invention is a metal-plastic hybrid material itself, i.e. a metal-plastic hybrid material comprising:

[0148] a substrate having at least one metallic surface, the at least one metallic surface being at least partially made of at least one steel and / or zinc and / or at least one alloy thereof,

[0149] a film or a dried or cured layer at least partially applied to said metal surface, obtainable by applying at least partially to said metal surface an aqueous acidic composition as defined in connection with step 1) of the method according to the invention,

[0150] optionally at least one thermoplastic polymer material TM1, which at least one thermoplastic polymer material TM1 is at least partially applied in foil form to the film or the dried or cured layer, preferably as defined in optional step 2) of the method of the invention, and

[0151] At least one thermoplastic polymer material TM2, which is in a form obtainable by injection molding and is at least partially applied to the film or to the dried or cured layer or (if present) to the foil, preferably as defined in step 3) of the method of the invention, this material TM2 being the same as or different from the optionally present thermoplastic polymer material TM1.

[0152] Preferably, the metal-plastic hybrid material is obtainable by the process of the invention. Preferably, the metal-plastic hybrid material is a laminate.

[0153] Preferably, the thermoplastic polymer material TM2 in a form obtainable by injection moulding has a total thickness in the range of 200 to 800 μm.

[0154] All preferred embodiments described above in conjunction with the inventive method, the inventive metal-plastic hybrid material obtainable by said method, the inventive use, and preferred embodiments thereof are also preferred embodiments of the inventive metal-plastic hybrid material itself.

[0155] Preferably, the film or the dried or cured layer, preferably the dried or cured, preferably the dried layer, applied at least partially on the metal surface of the metal-plastic hybrid material has a coating weight determined by XRF (X-ray fluorescence spectroscopy): in the presence of component a7) as defined below in the acidic aqueous composition of 1 to 90 mg / m 2 , more preferably 5 to 85 mg / m 2 , still more preferably 10 to 80 mg / m 2, even more preferably 15 to 75 mg / m 2 The layer formed after drying or curing, preferably drying, preferably has a coating weight determined by XRF (X-ray fluorescence spectroscopy): in the presence of component a4) as defined below in the acidic aqueous composition, of 0.5 to 10 mg / m 2 , more preferably 1 to 8 mg / m 2 , still more preferably 1.5 to 7 mg / m 2 , even more preferably 2 to 6 mg / m 2 of manganese, calculated in each case as metal.

[0156] Uses of Metal-Plastic Hybrid Materials

[0157] A further subject matter of the present invention is the use of the metal-plastic hybrid material or the metal-plastic hybrid material obtainable by the process according to the invention as a component in the automotive or construction industry.

[0158] All preferred embodiments described above in conjunction with the method of the invention, the metal-plastic hybrid material of the invention obtainable by the method, the above-mentioned use of the invention, the metal-plastic hybrid material of the invention itself, and preferred embodiments thereof are also preferred embodiments of the use of the metal-plastic hybrid material of the invention.

[0159] In particular, metal-plastic hybrid materials can be used to manufacture automotive parts, especially where weight reduction is desired. Further possible uses include the manufacture of battery housings and battery covers as well as panel controls in automobiles.

[0160] method

[0161] 1. Tensile Adhesion Strength

[0162] The tensile adhesion strength was measured by pull-off testing according to ISO 4624:2016. For the pull-off testing, a T-joint configuration was used.

[0163] 2. Average molecular weight M w and M n Determination

[0164] The number average molecular weight and weight average molecular weight (M) were measured according to the following schemes: n and M w): The samples were analyzed by SEC (size exclusion chromatography) equipped with a MALS detector. The absolute molar mass was obtained, where the dn / dC value was chosen to be equal to 0.1875 mL / g in order to obtain a recovery mass of about 90%. The polymer sample was dissolved in the mobile phase and the resulting solution was filtered with a 0.45 μm Millipore filter. The elution conditions were those below. Mobile phase: H2O 100% vol. 0.1M NaCl, 25mM NaH2PO4, 25mM Na2HPO4; 100ppm NaN3; flow rate: 1mL / min; column: Varian Aquagel OHmixed H, 8μm, 3*30cm; detection: RI (concentration detector Agilent) + MALLS (multi-angle laser light scattering) Mini DawnTristar + UV at 290nm; sample concentration: about 0.5wt% in the mobile phase; injection loop: 100μL. The polydispersity P can be obtained from the M n and M w Value calculation.

[0165] 3. Determination of free fluoride content

[0166] The free fluoride content is determined by means of a fluoride ion selective electrode. The electrode is calibrated using at least three stock solutions with known fluoride concentrations. The calibration process results in the establishment of a calibration curve. The fluoride content is then determined by using this curve.

[0167] 4. ICP-OES

[0168] According to DIN EN ISO 11885 (date: September 1, 2009), inductively coupled plasma atomic emission spectrometry (ICP-OES) is used to determine the amount of certain elements (such as zirconium, titanium, hafnium, etc.) in the sample analyzed. The sample is subjected to thermal excitation in an argon plasma generated by a high-frequency field, and the light emitted due to the electron transition becomes visible as spectral lines of the corresponding wavelength and is analyzed using an optical system. There is a linear relationship between the intensity of the emitted light and the concentration of the element in question. Prior to implementation, calibration measurements are performed according to the specific sample analyzed using known element standards (reference standards). These calibrations can be used to determine the concentration of unknown solutions, such as the concentration of the amount of titanium, zirconium and hafnium.

[0169] Examples

[0170] The following examples further illustrate the present invention but should not be construed as limiting its scope.

[0171] 1. Preparation of acidic aqueous coating compositions

[0172] 1.1 A number of acidic aqueous compositions A1 to A5 (according to the invention) and composition A6 (comparative) were prepared (each 1 L). All compositions were free of chromium. Each of compositions A1 to A5 contained one of the following water-soluble polymers P1 to P5:

[0173] P1: with M > 150,000 g / mol w of commercially available polyacrylic acid,

[0174] P2: a blend of P1 and a copolymer of maleic acid and acrylic acid,

[0175] P3: N-ethanolamine-modified polyvinylphenol,

[0176] P4: Copolymer of maleic acid and ethylene, and

[0177] P5: Copolymer of maleic acid and vinyl methyl ether.

[0178] Table 1:

[0179]

[0180] 1.2 A number of acidic aqueous compositions B1 to B7 (according to the invention) and composition B8 (comparative) were prepared (each 1 L). All compositions were free of chromium. Each of the compositions B1 to B7 contained one of the water-soluble polymers P1, P2, P4 or P5 as mentioned above:

[0181] Table 2:

[0182]

[0183] 2. Preprocessing

[0184] A hot-dip galvanized steel substrate in the form of a metal sheet (substrate T1, Panel MBZ automotive quality).

[0185] By using commercial alkaline products The substrate was cleaned with ELECTROLYTE S 5160 (at 60° C. to 70° C.) Then, it was rinsed with tap water and subsequently with deionized water (each for 30 seconds).

[0186] Then a contacting step is carried out, i.e. the surface of the substrate is contacted with one of the acidic aqueous compositions A1 to A6 or B1 to B8 described above in item 1. to form a conversion coating with adhesion-promoting properties on the surface of the substrate. In each case, the contacting step is carried out by spraying one of the acidic aqueous compositions onto the surface of the substrate for 60 seconds. Prior to spraying or application by a roller coater, the acidic aqueous composition is heated to 25° C.

[0187] After the contacting step, a drying step is carried out after a period of blowing air (15 minutes at 60° C. to 70° C.). The resulting dry layer thickness is in the range of 50 to 200 nm.

[0188] 3. Preparation of Metal-Plastic Hybrid Materials

[0189] Polyamide 6 (PA6; commercial product B27) is mixed with rubber materials and various standard additives to produce B3Z8 in order to reduce the water absorption of the polyamide. Before using this polyamide, it is placed in an oven before application to produce a "dry" polyamide. The resulting compounded PA6 is then applied by injection molding directly to the preheated surface of the substrate obtained after the pretreatment as described in item 2. The resulting laminate produced by injection molding has a thickness (of the plastic layer) ranging from 200 to 800 μm.

[0190] 4. Properties of the obtained metal-plastic hybrid materials

[0191] Various properties of the product obtained by the method described above in item 3. were studied. These properties were determined according to the test methods described above. The results are presented in Tables 2a to 2b. In particular, the adhesion strength was studied.

[0192] Table 2a:

[0193]

[0194] Table 2b:

[0195]

[0196] Thermoplastics were injected onto specific surface areas and adhesion strengths were compared between the different compositions. Surprisingly, pull-off testing showed that the minimum strength was obtained.

[0197] It was found that in the case when no polymer was present in the aqueous acidic composition used (ie when compositions A6 and B8 were used), no adhesion was observed between the plastic layer and the steel substrate, ie only an insufficient adhesion strength was observed.

Claims

1. A method for preparing a metal-plastic hybrid material, the material comprising a substrate having at least one metal surface and at least one thermoplastic material applied to the metal surface of the substrate, the method comprising at least steps 1) and 3) and optionally step 2), namely 1) applying an aqueous acidic composition at least partially to the at least one metal surface of the substrate to at least partially form a film on said surface, wherein the metal surface is at least partially made of at least one steel and / or zinc and / or at least one alloy thereof, and wherein the acidic aqueous composition comprises, in addition to water, at least one water-soluble polymer as at least one component a1), the at least one water-soluble polymer having at least one functional group selected from the group consisting of acid groups, hydroxyl groups, amino groups, and mixtures thereof, and optionally drying or curing the film to form a dried or cured layer, 2) optionally applying at least one thermoplastic polymer material TM1 at least partially in the form of a foil onto the film or onto the dried or cured layer obtained after step 1), and 3) injecting at least one thermoplastic polymer material TM2 at least partially onto the film or the dried or solidified layer obtained after step 1) or onto the foil optionally obtained after step 2) to form the metal-plastic hybrid material, the at least one thermoplastic polymer material TM2 being the same or different from the thermoplastic material TM1 optionally applied in step 2) and being present in a molten state.

2. The method according to claim 1, characterized in that The acidic aqueous composition used in step 1) has a pH value in the range of 0.1 to <7.0, preferably 0.5 to 6.5, more preferably 0.7 to 6.0, even more preferably 0.9 to 5.5, still more preferably 1.0 to 5.0, yet more preferably 1.2 to 4.5, yet more preferably 1.5 to 4.0, even more preferably 1.7 to 3.5, most preferably 1.8 to 3.

0.

3. The method according to claim 1 or 2, characterized in that: The at least one water-soluble polymer used as component a1) is present in the acidic aqueous composition in an amount ranging from 0.1 to 5.0 g / L, preferably 0.3 to 4.5 g / L, more preferably 0.5 to 4.0 g / L, still more preferably 0.7 to 3.5 g / L, yet more preferably 0.9 to 3.0 g / L, still more preferably 1.1 to 2.5 g / L, most preferably 1.3 to 2.0 g / L.

4. The method according to one or more of the preceding claims, characterized in that The at least one water-soluble polymer used as component a1) has at least one functional group selected from carboxylic acid groups, phosphonic acid groups, sulfonic acid groups, hydroxyl groups, amino groups, and mixtures thereof, more preferably selected from carboxylic acid groups, hydroxyl groups, amino groups, and mixtures thereof, even more preferably selected from carboxylic acid groups.

5. Method according to one or more of the preceding claims, characterized in that The at least one water-soluble polymer used as component a1) is a homopolymer or copolymer obtainable by polymerization of at least one ethylenically unsaturated monomer, at least a portion of which carries at least one functional group as defined in claims 1 and 4; preferably a homopolymer or copolymer obtainable by polymerization of at least one vinyl monomer and / or (meth)acrylic monomer, at least a portion of which carries at least one functional group as defined in claims 1 and 4.

6. Method according to one or more of the preceding claims, characterized in that The at least one water-soluble polymer used as component a1) is selected from (meth)acrylic acid homopolymers, in particular acrylic acid homopolymers; copolymers of (meth)acrylic acid and at least one ethylenically unsaturated monomer different from (meth)acrylic acid, in particular copolymers of (meth)acrylic acid and maleic acid; copolymers of maleic acid and at least one ethylenically unsaturated monomer different from maleic acid, in particular copolymers of maleic acid and ethylene and / or propylene and / or at least one alkyl vinyl ether such as methyl vinyl ether; copolymers of vinylphosphonic acid and at least one ethylenically unsaturated monomer different from vinylphosphonic ...propylene and maleic acid; copolymers of vinyl phenol and at least one ethylenically unsaturated monomer different from vinyl phenol; copolymers of vinyl mercaptoethanol and at least one ethylenically unsaturated monomer different from vinyl mercaptoethanol; homopolymers and copolymers of vinyl phenol and / or vinyl alcohol which have been modified with at least one amine, preferably at least one primary amine such as N-ethanolamine and / or N-methylglucamine; and mixtures thereof.

7. Method according to one or more of the preceding claims, characterized in that The at least one water-soluble polymer used as component a1) is selected from (meth)acrylic acid homopolymers, in particular acrylic acid homopolymers; copolymers of (meth)acrylic acid and at least one ethylenically unsaturated monomer different from (meth)acrylic acid, in particular copolymers of (meth)acrylic acid and maleic acid; copolymers of maleic acid and at least one ethylenically unsaturated monomer different from maleic acid, in particular copolymers of maleic acid and ethylene and / or propylene and / or at least one alkyl vinyl ether, such as methyl vinyl ether; homopolymers of vinyl alcohol; copolymers of vinyl alcohol and at least one ethylenically unsaturated monomer different from vinyl alcohol; homopolymers and copolymers of vinylphenol and / or vinyl alcohol, which have been modified with at least one amine, preferably at least one primary amine, such as N-ethanolamine and / or N-methylglucamine; and mixtures thereof, Preferably selected from N-methylglucamine-modified poly(vinylphenol), N-ethanolamine-modified poly(vinylphenol), poly(maleic acid-co-vinyl methyl ether), poly(maleic acid-co-acrylic acid), polyacrylic acid, poly(vinyl-phosphonic acid-co-acrylic acid), poly(acrylic acid-co-maleic acid-co-vinylphosphonic acid), poly(acrylic acid-co-maleic acid-co-vinylmercaptoethanol) and mixtures thereof.

8. Method according to one or more of the preceding claims, characterized in that The aqueous acidic composition used in step 1) further comprises zinc cations as at least one component a2), preferably in an amount in the range of 0.1 to 8.0 g / L, even more preferably 0.2 to 6.0 g / L, still more preferably 0.3 to 5.0 g / L, yet more preferably 0.5 to 3.0 g / L, in each case calculated as metal.

9. Method according to one or more of the preceding claims, characterized in that (i) The aqueous acidic composition used in step 1) further comprises at least one of components a3) and a4), preferably both a3) and a4) or only a4), namely as at least one component a3), at least one metal cation selected from the group of titanium ions, zirconium ions and hafnium ions, and mixtures thereof, preferably at least one metal cation selected from the group of titanium ions and zirconium ions and mixtures thereof, preferably in an amount in the range of 5 to 5000 ppm, more preferably 7.5 to 4000 ppm, still more preferably 10 to 3000 ppm, even more preferably 12.5 to 2000 ppm, yet more preferably 15 to 1000 ppm, in particular 17.5 to 500 ppm, more particularly 20 to 300 ppm, most preferably 30 to 200 ppm, in each case calculated as metal, and / or As at least one component a4) manganese cation, preferably in an amount in the range of 0.1 to 5.0 g / L, more preferably 0.1 to 4.0 g / L, even more preferably 0.2 to 3.5 g / L, still more preferably 0.3 to 3.0 g / L, yet more preferably 0.5 to 2.5 g / L, in each case calculated as metal, and optionally further comprises free fluoride anions as at least one optional component a5), and / or at least one organosilane as optional component a6), preferably in an amount in the range of 10 to 200 ppm, or characterized by, (ii) The aqueous acidic composition used in step 1) further comprises at least component a7), namely As at least one component a7), phosphate anions are preferably present in an amount in the range of 1 to 150 g / L, more preferably 2.0 to 125 g / L, even more preferably 3.0 to 100 g / L, still more preferably 4.0 to 95 g / L, yet more preferably 5.0 or 7.5 to 90 g / L, in each case calculated as PO, and optionally further comprises manganese cations as at least one component a4), preferably in an amount in the range of 0.1 to 5.0 g / L, more preferably 0.1 to 4.0 g / L, even more preferably 0.2 to 3.5 g / L, still more preferably 0.3 to 3.0 g / L, yet more preferably 0.5 to 2.5 g / L, in each case calculated as metal, wherein in case (i), preferably no phosphate anion a7) is present, and In the case of (ii), the acidic aqueous composition preferably contains no or substantially no free fluoride anions a5).

10. Method according to one or more of the preceding claims, characterized in that The at least one thermoplastic polymer material TM1 and the at least one thermoplastic polymer material TM2 are independently selected from polyamides; polyesters, in particular PET and / or PBT; polyurethanes; polycarbonates; polyolefins, in particular polypropylene and / or polyethylene; and mixtures thereof, wherein preferably, the at least one thermoplastic polymer material TM2 is selected from polyamides, in particular polyamides compounded with at least one rubber material, and wherein preferably, the at least one thermoplastic polymer material TM1 - if present - is selected from polyolefins, in particular polypropylene and / or polyethylene.

11. A metal-plastic hybrid material obtainable by a process according to one or more of claims 1 to 10.

12. Use of a water-soluble polymer as defined above in one or more of claims 1 and 3 to 7 as component a1) of an acidic aqueous composition, preferably the use of said water-soluble polymer when present in an acidic aqueous composition as defined in one or more of claims 1 to 9 for adhering a metallic surface of a substrate at least partially made of at least one steel and / or zinc and / or at least one alloy thereof to a thermoplastic polymer material which is present on said surface in the form of a foil or is applied to said surface by injection molding.

13. A metal-plastic hybrid material comprising a substrate having at least one metallic surface, the at least one metallic surface being at least partially made of at least one steel and / or zinc and / or at least one alloy thereof, a film or a dried or cured layer at least partially applied to said metal surface, obtainable by applying at least partially to said metal surface an aqueous acidic composition as defined in conjunction with step 1) in one or more of the preceding claims 1 to 9, optionally at least one thermoplastic polymer material TM1, which at least one thermoplastic polymer material TM1 is at least partially applied in foil form to the film or the dried or cured layer, preferably as defined in optional step 2) in one or more of claims 1 to 9, and At least one thermoplastic polymer material TM2, which is in a form obtainable by injection molding and is at least partially applied to the film or to the dried or cured layer or - if present - to the foil, preferably as defined in step 3) in one or more of claims 1 to 9, which material TM2 is the same as or different from the optionally present thermoplastic polymer material TM1.

14. The metal-plastic hybrid material according to claim 11 or 13, characterized in that: The film or the dried or cured layer, preferably the dried or cured layer, obtainable by applying the aqueous acidic composition has a dry layer thickness in the range of 100 to 1000 nm and / or is characterized in that the film or the dried or cured layer, preferably the dried or cured layer, obtainable by applying the aqueous acidic composition has a coating weight determined by XRF (X-ray fluorescence spectroscopy): in the presence of component a7) as defined below in the acidic aqueous composition, from 1 to 90 mg / m 2 , more preferably 5 to 85 mg / m 2 , still more preferably 10 to 80 mg / m 2 , even more preferably 15 to 75 mg / m 2 phosphor, in each case calculated as P2O5; and / or in the presence of component a4) as defined below in the acidic aqueous composition, from 0.5 to 10 mg / m 2 , more preferably 1 to 8 mg / m 2 , still more preferably 1.5 to 7 mg / m 2 , even more preferably 2 to 6 mg / m 2 of manganese, calculated in each case as metal.

15. Use of the metal-plastic hybrid material according to one or more of claims 11, 13 or 14 as a component in the automotive or construction industry.

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