Terpene for use as additive for lowering cleaner temperatures in cleaning compositions

Abstract

The present invention relates to a method of cleaning of a metallic surface of a substrate comprising at least step 1), i.e., contacting the surface with an aqueous alkaline composition for cleaning the substrate, which comprises water, an alkalinity inducing source, a surfactant, a terpene, optionally a complexing agent, optionally a decalcifying agent, optionally an alcohol, and optionally also step 2), i.e. rinsing the cleaned surface obtained after step 1) at least once with an aqueous rinsing composition, and wherein the aqueous alkaline composition used in step 1) optionally has a temperature in a range of from 20 to 50 °C, to the aqueous alkaline cleaning composition as such, to a use of a terpene when incorporated into an aqueous alkaline cleaning composition for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates, to a substrate obtainable by the aforementioned method and to a use of the aqueous alkaline cleaning composition in the aforementioned method for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

Description

[0001] 2024P00070WQ I L025965PCT 1 March 16, 2026 Chemetall GmbH

[0002] Terpene for use as additive for lowering cleaner temperatures in cleaning compositions

[0003] The present invention relates to a method for cleaning of metallic surfaces of substrates, to a cleaning composition suitable for use in this method, to a use of a terpene incorporated into a cleaning composition, to a cleaned substrate, being obtainable by the said method and to a use of the cleaning composition in the said method for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

[0004] Background of the invention

[0005] In metal-processing industries such as the general industry or cold forming industry, metal parts are usually cleaned with cleaning compositions in order to remove impurities on their surfaces, which may be attached physically or chemically on the metallic surface of the substrate such as residual oils / lubricants / particles / oxidation products etc., before they enter subsequent steps of further processing.

[0006] In cleaning compositions various additives can be used in order to enhance the cleaning process. In the state of the art, it is known that orange oil can be used as a cleaner agent.

[0007] In the patent literature there are multiple examples which describe cleaning compositions containing terpenes.

[0008] US5277836 A describes a cleaning composition comprising a mixture of (A) at least about 10% by weight of a terpene, (B) from about 1% to about 20% by weight of a polyalkoxylated alcohol, an alkyl or alkenyl succinate, or mixtures thereof, and (C) water, wherein the mixture has an acidic pH and methods of using the same. These compositions have improved grease cutting and rust inhibiting abilities. The cleaning composition described therein is an alcohol-based cleaning composition. Substrates mentioned therein are hard and flexible surfaces.

[0009] WO 2013 / 162926 A1 describes a water based cleaner composition for removing permanent markers, where it is told, that the terpenes are used for the discoloration. Aqueous hard surface cleaner compositions useful for removing permanent ink are disclosed. The compositions comprise 75 to 99 wt.% of water; 0.1 to 5 wt.% of a monoterpene; 0.1 to 5 wt.% of a C10-C17 fatty acid derivative; and 0.1 to 5 wt.% of one or more surfactants. The fatty acid derivative is selected from N,N-dialkyl amides, N,N-dialkyl esteramines, and N,N-dialkylamidoamines. Preferably, a base such as sodium carbonate or monoethanolamine is also included. The document describes concentrates comprising the non-aqueous components recited above, as well as other applications for the cleaners and concentrates such as graffiti removers and permanent ink erasers. The combination of a monoterpene and certain fatty acid derivatives, especially fatty N,N-dialkyl amides, unexpectedly enables even dilute aqueous compositions to rapidly decolorize black permanent marker from hard, non-porous surfaces.

[0010] US6150315 A describes a high viscous cleaning composition which is used at room temperature containing minimum 60% water, thickener and terpenes. The cleaning composition is especially useful for cleaning outdoor2024P00070WQ I L025965PCT 2 March 16, 2026 Chemetall GmbH

[0011] sporting equipment such as firearms. The viscosity of those cleaners should by > lOOOCPs. The cleaning composition is applied with a wipe for firearms cleaning. Nothing is told here about the cleaning time or if the main cleaning effect comes from the wiping action.

[0012] As can be seen above there are multiple cleaning compositions described in the state of the art. Most of the cleaners contain organic solvents but there are also examples which are VOC free in water-based systems. Nevertheless, the state of the art describes in principle compositions about cleaner, but nothing is told if terpenes can be used as an additive for existing cleaning compositions to reduce the cleaner application temperature while keeping excellent cleaning performance. The use of such cleaning compositions as de-phosphating agents is not described in literature.

[0013] These days, resource conservation as well as energy savings are in the spotlight. Out of this demand lower treatment temperatures are in focus. Especially cleaner temperature normally needs higher elevated temperatures to obtain high cleaning performance. This could lead to excess use of energy in mass production like typical production of cold forming parts. Since phosphor has a negative impact on the mechanical behavior of fastening means as for example screws through phosphor introduced embrittlement, this industry wants to eliminate phosphor residues in total. Sadly, phosphor containing conversion coatings are used as separation layer and as lubricant carrier during the forming process. Thus, de-phosphating cleaning agents are used at ~ 70°C to eliminate the tribological phosphor containing layer.

[0014] Thus, there is a need to provide a method for effectively cleaning substrates having metallic surfaces such as surfaces made of steel, wherein such a method does not lead to the disadvantages observed when using conventional cleaning compositions known in the prior art, including environmental and / or health concerns and / or economic disadvantages.

[0015] Problem

[0016] It has been therefore an objective underlying the present invention to provide a method for effectively cleaning substrates having metallic surfaces such as surfaces made of steel, wherein such a method does not lead to the disadvantages observed when using conventional cleaning compositions known in the prior art, including environmental and / or health concerns and / or economic disadvantages.

[0017] Solution

[0018] This objective has been solved by the subject-matter of the claims of the present application as well as by the preferred embodiments thereof disclosed in this specification, i.e. , by the subject matter described herein.

[0019] A first subject-matter of the present invention is a method of cleaning of at least one metallic surface of at least one substrate the method comprising at least step 1) and optionally also step 2), namely2024P00070WQ I L025965PCT 3 March 16, 2026 Chemetall GmbH

[0020] 1 ) contacting the at least one surface of the at least one substrate at least in portion with an aqueous alkaline composition for cleaning the substrate,

[0021] wherein the aqueous alkaline composition comprises besides water at least constituents a1) and a2) and optionally one or more of a3) to a6), which are different from one of another, namely at least one alkalinity inducing source as constituent a1),

[0022] at least one surfactant as constituent a2), preferably in an amount in a range of from 0.015 wt.-% to 0.060 wt.-%

[0023] optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), and

[0024] optionally at least one terpene as further constituent a6), which preferably is present and which preferably is unsaturated, and which more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene,

[0025] 2) optionally rinsing the cleaned surface obtained after step 1) at least once with an aqueous rinsing composition,

[0026] wherein optionally the aqueous alkaline composition used in step 1) has a temperature in a range of from 20 to 50 °C, preferably wherein the aqueous alkaline composition used in step 1) has a temperature in a range of from 20 to 50 °C.

[0027] A further subject-matter of the present invention is an aqueous alkaline cleaning composition as defined hereinbefore and hereinafter and as used in step 1) of the cleaning method, which comprises besides water at least constituents a1) and a2) and optionally one or more of a3) to a6), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2), optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), wherein optionally at least one terpene, which preferably is unsaturated and more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene, is present as further constituent a6) in the aqueous alkaline composition.

[0028] A further subject-matter of the present invention is an aqueous alkaline cleaning composition as defined hereinbefore and hereinafter and as used in step 1) of the cleaning method, which comprises besides water at least constituents a1), a2) and a6) and optionally one or more of a3) to a5), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2), optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), wherein at least one terpene, which preferably is unsaturated and more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene,2024P00070WQ I L025965PCT 4 March 16, 2026 Chemetall GmbH

[0029] dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene, is present as further constituent a6) in the aqueous alkaline composition.

[0030] A further subject-matter of the present invention is a use of at least one terpene as defined hereinbefore and hereinafter as constituent a6) of the aqueous alkaline composition, preferably when incorporated into an aqueous alkaline cleaning composition, preferably into an inventive aqueous alkaline cleaning composition defined hereinbefore and hereinafter for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

[0031] A further subject-matter of the present invention is a substrate, which is a cleaned substrate being obtainable by the cleaning method according to the present invention as defined hereinbefore and hereinafter.

[0032] A further subject-matter of the present invention is the use of the inventive aqueous alkaline cleaning composition in an inventive method as defined hereinbefore and hereinafter for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

[0033] It has been surprisingly found that with the method according to the present invention as defined hereinbefore and hereinafter and with the inventive aqueous alkaline cleaning composition according to the present invention as defined hereinbefore and hereinafter the cleaning temperature can be lowered while maintaining the cleaning performance. Surprisingly, terpenes can be used to solve this task, especially the terpenes, that are found in orange oil like limonene.

[0034] Moreover, it has been found that applying the method according to the present invention and using the cleaning composition according to the present invention does not lead to the disadvantages observed, when using conventional cleaning compositions and conventional cleaning methods known in the prior art. In particular, applying the method according to the present invention and using the cleaning composition according to the present invention does not lead to environmental and / or health concerns and / or economic disadvantages, in particular due to the constituents used for preparing the cleaning composition and the rinsing composition(s).

[0035] Detailed description of the invention

[0036] The term "comprising” in the sense of the present invention, in connection for example with the aqueous alkaline composition and / or the aqueous rinsing composition has the meaning of "consisting of'. With regard, e.g., to any of these compositions referred to hereinbefore, it is possible - in addition to all mandatory constituents present therein - for one or more of the further optional constituents identified hereinafter to be also included therein. All constituents may in each case be present in their preferred embodiments as identified below.2024P00070WQ I L025965PCT 5 March 16, 2026 Chemetall GmbH

[0037] The proportions and amounts in wt.-% (% by weight) of any of the constituents given hereinafter, which are present in each of the compositions add up to 100 wt.-%, based in each case on the total weight of the respective composition.

[0038] Orange terpene

[0039] As mentioned earlier it is known that orange oil can be used as a cleaner agent. Orange terpene is a natural solvent produced from a concentrated form of orange oil. The liquid consists of approx. 90% terpenes, mainly d-limonene, and 1-2.5% odor-determining aldehydes, as well as other volatile components from the peel of citrus fruits. Like many cleaning agents, it can irritate the skin and respiratory system, which is why it should be used with caution. Orange terpene can be used almost indefinitely. For example, to remove stains from grease, oil or wax on various surfaces such as metal, textiles and plastics. In orange juice production, the peel of the fruit remains in very large quantities. By cold pressing the orange peel, oils are extracted which are the starting material for the production of orange terpenes. As a result, the liquid also has the typical smell of orange peel. Further distillation of the oils produces the terpenes.

[0040] Cleaning method

[0041] The cleaning method according to the present invention comprises at least step 1) and optionally also step 2). The method may, however, comprise one or more further additional optional steps.

[0042] Substrate

[0043] In step 1) of the cleaning method at least one metallic surface of at least one substrate is contacted with an aqueous alkaline composition.

[0044] The term "metallic surface” in the sense of the present invention preferably means that the surface of the substrate used is at least partially made of at least one metal, i.e., that at least one region of said surface is made of at least one metal and / or alloy thereof. The surface can consist of different regions comprising different metals and / or alloys thereof. Preferably, the overall surface of the substrate is made of at least one metal and / or alloy thereof, more preferably, the whole substrate is made of at least one metal and / or alloy thereof, i.e., the substrate consists of at least one metal and / or alloy thereof. Preferably, the substrate is an electrically conductive substrate, which is used customarily and known to the skilled person.

[0045] The metallic surface of the substrate can be made of any kinds of metals and / or alloys thereof. Preferably, the metal and / or alloy thereof is selected from the group consisting of steel, steel alloys, aluminum, aluminum alloys, zinc, zinc alloys such as zinc-magnesium alloys and / or zinc-iron alloys, magnesium, magnesium alloys such as zinc- magnesium alloys. Steel and steel alloys are preferably selected from cold rolled steel (CRS), hot rolled steel (HRS), galvanized steel (zinc plated steel) such as hot-dip galvanized steel (hot zinc dipped steel; HDG) and electrolytically galvanized steel (EG), and steel coated at least in portion with at least one kind of zinc-aluminum-magnesium alloy (ZM), and mixtures thereof.2024P00070WQ I L025965PCT 6 March 16, 2026 Chemetall GmbH

[0046] The geometry and shape of the substrate is not limited. Examples include strips, sheets, slugs, wires, and coils as well as parts of vehicles or vehicle bodies, which are, e.g., suitable for use in the cold forming industry.

[0047] However, it is preferred that the at least one metallic surface of the at least one substrate is at least partially made of at least one kind of steel, and that the at least one substrate is selected from fastener means like bolts, screws, tubes, nuts, rivets, pins, studs, washers. It is important that the at least one substrate has already been pressed and pulled before the cleaning process. In the below described cleaning trials screws have been used, however every other fastener means or other formed / machined parts can also be used.

[0048] Step 1)

[0049] According to step 1) at least one surface of at least one substrate is contacted at least in portion with an aqueous alkaline composition for cleaning the substrate. By contacting step 1) cleaning of the portion of the surface is achieved.

[0050] The cleaning method including cleaning step 1) preferably represents part of a pretreatment. The term "pretreatment” as used herein is preferably used in accordance with the term "surface pretreatment'' as defined in Rdmpp Lexikon "Lacke und Druckfarben” (Publisher: Ulrich Zorll, Editor: Hans-Jurgen P. Adler - Stuttgart; New York: Thieme, 1998; term: "Oberflachenvorbehandlung” page 417). On metallic substrates or substrates having metallic surfaces used in accordance with the present invention, according to DIN 50902: 1994-07, the first step(s) of a surface treatment is / are often one or more cleaning step(s) with aqueous or non-aqueous cleaning compositions (also called "surface preparation step”). In case of the present invention, said step involves use of an aqueous alkaline cleaning composition. In accordance with the above internationally valid definitions of a "pretreatment” of metallic substrates, a pretreatment method according to the present invention, hence, preferably encompasses the cleaning step 1) of the inventive method, which represents a surface preparing cleaning step.

[0051] The term "at least in portion” preferably means in this context, in accordance with the general understanding of said term, that in some cases it might be desired or sufficient to contact not the whole surface of the substrate with the cleaning composition. If only part of the surface is contacted with the composition, it is typically the same part for all steps of the method. However, generally, it is desired to contact the whole surface of the substrate.

[0052] The "contacting” according to step 1) can be, e.g., a spraying, a dipping or a roll coating step or any combination thereof. The aqueous alkaline composition can also be applied by flooding the surface or even manually by wiping or brushing. Preferred is spraying, dipping or roll coating or any combination thereof, most preferred is spraying or dipping, in particular dipping.2024P00070WQ I L025965PCT 7 March 16, 2026 Chemetall GmbH

[0053] The treatment time, i.e. , the period of time the surface is contacted with the aqueous alkaline composition in step 1), is preferably for a period of 1 to 20 minutes, more preferably for a period of 1 to 10 minutes, still more preferably for a period of 1 to 5 minutes, yet more preferably for a period of 1 to 3 minutes.

[0054] The aqueous alkaline composition used in step 1) has a temperature in a range of from 20 to 50 °C, more preferably in a range of from 25 to 40 °C, still more preferably of from 25 to 35 °C.

[0055] Aqueous alkaline composition used in step 1)

[0056] The aqueous alkaline cleaning composition used in step 1) comprises besides water at least constituents a1) and a2) and optionally one or more of a3) to a6), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2), optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), wherein optionally at least one terpene, which preferably is unsaturated and more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene, is present as further constituent a6) in the aqueous alkaline composition.

[0057] The aqueous alkaline cleaning composition used in step 1) is suitable for use as dephosphating agent and hence preferably represents a dephosphating composition. Thus, the aqueous alkaline cleaning composition used in step 1) is able to remove a conversion coating being present on at least one metallic surface of a substrate or any residue of such a conversion coating, in particular of a phosphate-containing conversion coating. Conventional dephosphating compositions are used in cleaning processes, in which said compositions have comparably high temperatures of, e.g., >50 °C or at even 70 °C. It has been found that, due to the presence of the at least one terpene constituent a6), the cleaning temperature can be significantly reduced, e.g., down to 25°C, or to a temperature in a range of from 20 to 50 °C without detrimental effects of the cleaning efficacy.

[0058] It is preferred that the aqueous alkaline cleaning composition used in step 1) comprises besides water at least constituents a1), a2) and a6) and optionally one or more of a3) to a5), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2), optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), wherein at least one terpene, which preferably is unsaturated and more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene, is present as further constituent a6) in the aqueous alkaline composition.

[0059] Preferably, the aqueous alkaline composition used in step 1) has a pH value in a range of from >7.5 to 12.5 or <14.0, preferably of from >9 to <13.5, more preferably of from >10.0 to <13.5. The best effect is achieved at a pH value of 13.1.2024P00070WQ I L025965PCT 8 March 16, 2026 Chemetall GmbH

[0060] The pH value can be in particular adjusted by using constituent a1), in particular sodium and / or potassium hydroxide and / or carbonate, for alkaline adjustment, and can be in particular adjusted in case acidic adjustment is needed by at least one inorganic acid such as phosphoric and / or boric acid.

[0061] The term "aqueous” with respect to the aqueous composition used in step 1) in the sense of the present invention preferably means that the composition is a composition containing at least 45 wt.-%, preferably at least 50 wt.-%, more preferably at least 60 wt.-% of water, still more preferably at least 70 wt.-% of water, even more preferably at least 80 wt.-% of water. The aqueous alkaline composition can be a dispersion or solution. Preferably, it is a solution.

[0062] Constituent a1)

[0063] At least one alkalinity inducing source is used as constituent a1). All kinds of alkalinity inducing sources, in particular anion sources, can be used. Preferably, at least one hydroxide anion and / or carbonate anion source, preferably a metal salt such as sodium and / or potassium hydroxide and / or carbonate, in particular potassium hydroxide and / or carbonate, is used for preparing the aqueous alkaline composition. Hence, the aqueous alkaline composition comprises preferably hydroxide and / or carbonate anions as constituent a1). Preferably, the aqueous alkaline composition comprises the at least one alkalinity inducing source present as constituent a1) in an amount such that the required alkalinity is met. The at least one alkalinity inducing source being present as constituent a1) is present in an amount in a range of from 2.8 wt.-% to 6.0 wt.-%, preferably of from 3.0 wt.-% to 5.0 wt.-%, more preferably of from 4.0 wt.-% to 4.8 wt.-%,

[0064] Constituent a2)

[0065] At least one surfactant is used as constituent a2). The term surfactant (surface active agent) as used herein is preferably used in accordance with the term "tenside” as defined in Rbmpp Lexikon "Lacke und Druckfarben” (Publisher: Ulrich Zorll, Editor: Hans-Jurgen P. Adler - Stuttgart; New York: Thieme, 1998; term: "tenside” pages 557 and 558). Suitable surfactants are known to a person skilled in the art and, e.g., disclosed in WO 2020 / 200838 A1. Preferably, the at least one surfactant is selected from non-ionic, anionic and / or cationic surfactants, most preferably from non-ionic surfactants.

[0066] Suitable non-ionic surfactants include in particular alkylphenol alkoxylates, especially alkylphenol ethoxylates, having C6 to C14 alkyl chains and a degree of alkoxylation of 5 to 30 mol per mole of phenol, alkylpolyglucosides having an alkyl chain length of C8 to C22, preferably C10 to C18, and containing 1 to 20, preferably 1 to 5, glucoside units, fatty acid amide alkoxylates, fatty acid alkanolamide alkoxylates, N-al kylglucamides or else block copolymers consisting of ethylene oxide, propylene oxide and / or butylene oxide, and alkoxylated C8 to 022 alcohols such as fatty alcohol alkoxylates, oxoprocess alcohol alkoxylates and Guerbet alcohol alkoxylates, where the alkoxylation may take place with ethylene oxide, propylene oxide, butylene oxide and / or a mixture of these, as a block copolymer or random copolymer. The alcohols preferably have 8 to 18 carbon atoms; the degree of alkoxylation ranges2024P00070WQ I L025965PCT 9 March 16, 2026 Chemetall GmbH

[0067] typically between 2 to 50 mol, preferably 3 to 20 mol, of at least one of the stated alkylene oxides per mole of alcohol. The alkylene oxide head group may additionally contain the following so-called endcapping groups as a modification: benzyl, methyl and / or tert-butyl capping.

[0068] Depending on the application, the following anionic surfactants in particular can be used: fatty alcohol sulfates having alkyl chain lengths of 8 to 22, preferably 10 to 18, carbon atoms, for example lauryl sulfate, cetyl sulfate, myristyl sulfate, palmityl sulfate or stearyl sulfate, alkyl ether sulfates having alkyl chain lengths of 8 to 22, preferably 10 to 18, carbon atoms, and linear C8 to C20 alkylbenzenesulfonates or else alkanesulfonates and soaps, such as sodium or potassium salts of C8 to 024 carboxylic acids.

[0069] As outlined above, however, the at least one surfactant preferably is at least one nonionic surfactant. Within the majority of applications, the foaming tendency of anionic surfactants is too high, while cationic surfactants often attach to the metallic surface, and may consequently give rise to problems within the deposition of conversion coating films to be subsequently applied.

[0070] Preferably, the at least one surfactant being present as constituent a2) is selected from non-ionic, anionic and / or cationic surfactants, preferably from non-ionic surfactants, and / or the at least one surfactant being present as constituent a2) is present in an amount in a range of from 0.015 wt.-% to 0.06 wt.-%, preferably of from 0.02 wt.-% to 0.05 wt.-%, more preferably of from 0.03 wt.-% to 0.04 wt.-%.

[0071] Further, a mixture of non-ionic and anionic surfactants, each in the above-mentioned ranges, is especially preferred.

[0072] Constituent a3)

[0073] Optionally at least one complexing agent is used as constituent a3). Suitable complexing agents are known to a person skilled in the art.

[0074] Preferably, the at least one complexing agent being optionally present as constituent a3) is selected from (I) carboxylic acids, salts thereof, derivatives, in particular esters, thereof, and mixtures thereof, wherein the carboxylic acids include polymeric carboxylic acids in each case, (ii) sulfamic acids, (iii) phosphonic acid, phosphonates and derivatives of phosphonic acid such as esters thereof, (iv) polyols, in particular having two or more OH-groups, wherein the polyols include polymeric polyols, and (v) polyethyleneimines, and mixtures of (i) to (v). More preferably, the at least one complexing agent being optionally present as at least one optional constituent a3) is selected from (i) carboxylic acids, salts thereof, derivatives, in particular esters, thereof, and mixtures thereof, wherein the carboxylic acids include polymeric carboxylic acids in each case, (iii) phosphonic acid, phosphonates and derivatives of phosphonic acid such as esters thereof, and mixtures thereof. Even more preferably, the at least one complexing agent being optionally present as at least one optional constituent a3) is selected from (i) carboxylic acids, salts thereof, derivatives, in particular esters, thereof, and mixtures thereof, wherein the carboxylic acids include polymeric carboxylic acids in each case. Exemplary suitable complexing agents are HEDP (1-2024P00070WQ I L025965PCT 10 March 16, 2026 Chemetall GmbH

[0075] hydroxyethylidene- 1 ,1-diphosphonic acid), EDTMP (ethylenediamine tetra(methylene phosphonic acid), MGDA-Na3 (methylglycinediacetic acid trisodium salt), DTPA-Na5 (diethylenetriaminepentaacetic acid pentasodium salt), PBTC-Na4 (2- phosphonobutane-1, 2, 4, -tricarboxylic acid tetrasodium salt), polyethyleneimines, amido sulfonic acid, and mixtures thereof.

[0076] Preferably, the at least one complexing agent being optionally present as constituent a3) is selected from (I) carboxylic acids, salts thereof, derivatives, in particular esters, thereof, and mixtures thereof, wherein the carboxylic acids include polymeric carboxylic acids in each case, and the at least one complexing agent is present in an amount in a range of from 2.0 wt.-% to 4.5 wt.-%, preferably of 2.5 wt.-% to 4.0 wt.-%, more preferably of from 3,0 wt.-% to 3,5 wt.-%.

[0077] Constituent a4)

[0078] The at least one decalcifying agent being optionally present as constituent a4) is selected from a chelating agent chosen from EDTA or HEDP or a mixture thereof and is present in an amount in a range of from 0.05 wt.-% to 0.1 wt.-%, preferably of from 0.06 wt.-% to 0.09 wt.-%.

[0079] Constituent a5)

[0080] The at least one alcohol being optionally present as constituent a5) is selected from ethylene glycol or propylene glycol or a mixture thereof and is present in an amount in a range of from 0.01 wt.-% to 0.05 wt.-%, preferably of from 0.015 wt.-% to 0.03 wt.-%.

[0081] Constituent a6)

[0082] The at least one terpene, if present, is present in an amount in a range of from 0.05 Vol.-% to 2.5 Vol .-%, preferably of from 0.1 Vol.-% to 2.25 Vol.-%, more preferably of from 0.15 Vol. -% to 2.0 Vol.-%, even more preferably of from 0.2 Vol.-% to 1.8 Vol.-%.

[0083] Preferably, the at least one terpene is an unsaturated terpene.

[0084] The at least one terpene, if present, is more preferably chosen from the group, consisting of alpha-pinene, betapinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene.

[0085] Especially preferred is orange terpene. Orange terpene has already been described hereinbefore.

[0086] In case if optional step 2) of the inventive method is performed, the aqueous rinsing composition used in said step 2) preferably consists or essentially consists of water only.2024P00070WQ I L025965PCT 11 March 16, 2026 Chemetall GmbH

[0087] Aqueous alkaline composition

[0088] A further subject-matter of the present invention is an aqueous cleaning composition as defined hereinbefore and hereinafter and as used in step 1) of the cleaning method, which comprises besides water at least constituents a1) and a2) and optionally one or more of a3) to a6), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2), optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), wherein optionally at least one terpene, which preferably is unsaturated and more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene, is present as further constituent a6) in the aqueous alkaline composition.

[0089] A further subject-matter of the present invention is an aqueous cleaning composition as defined hereinbefore and hereinafter and as used in step 1) of the cleaning method, which comprises besides water at least constituents a1), a2) and a6) and optionally one or more of a3) to a5), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2), optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), wherein at least one terpene, which preferably is unsaturated and more preferably is selected from the group consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene, is present as further constituent a6) in the aqueous alkaline composition.

[0090] All preferred embodiments described above herein in connection with the inventive cleaning method and preferred embodiments thereof are also preferred embodiments of the inventive composition

[0091] Substrate, being cleaned

[0092] A further subject-matter of the present invention is a substrate, which is a cleaned substrate being obtainable by the cleaning method according to the present invention as defined hereinbefore and hereinafter.

[0093] Use

[0094] A further subject-matter of the present invention is a use of at least one terpene as constituent a6) of the aqueous alkaline composition as defined hereinbefore and hereinafter preferably when incorporated into an aqueous alkaline cleaning composition, as defined hereinbefore and hereinafter for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.2024P00070WQ I L025965PCT 12 March 16, 2026 Chemetall GmbH

[0095] A further subject-matter of the present invention is a use of the aqueous alkaline cleaning composition as defined hereinbefore and hereinafter in a method as defined hereinbefore and hereinafter for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

[0096] It is clear to a person skilled in the art that the aforementioned term "enhanced” means "improved” and thus relates to an "increased” dephosphatisation and polymer film removal of metallic surfaces of substrates.

[0097] All preferred embodiments described above herein in connection with the inventive cleaning method and the inventive composition and in each case preferred embodiments thereof are also preferred embodiments of the inventive cleaned, substrate.

[0098] The use case, on which the current investigations are focused on, is the cleaning of cold formed products like fastener means like bolts, screws, tubes, nuts, rivets, pins, studs, washers. During the experiments preferably fastener means have been screws, due to the fact, that a screw is a complex geometry with a defined amount of dirt on it. To produce such products typical two-layer tribological systems are used. As a separation layer normally a zinc phosphate conversion coating is applied and from the lubricant side, a sodium stearate containing lubricant, or a polymeric lubricant can be used. The cleaning of those systems is done by using alkaline cleaners containing sodium hydroxide as well as complexing agents like gluconate and surfactants. Normally such a cleaning system is used at higher temperatures up to 70°C. By adding at least one terpene such as orange oil to such a system, it has been possible, to reduce the cleaning temperature down to 25°C by adding an amount in a range of from 0.05 Vol.-% to 2.5 Vol.-%, preferably of from 0.1 Vol.-% to 2.25 Vol .-%, more preferably of from 0.15 Vol. -% to 2.0 Vol.-%, even more preferably of from 0.2 Vol.-% to 1.8 Vol.-% of orange oil. Increasing the additive up to 2 Vol% has also no negative influence on the cleaning performance. At higher levels, a negative performance was not observed but a strong odor of oranges. This smell can be perceived as unpleasant by the user. The experiments have been carried out with fastener means and the cleaning performance was then judged with the naked eye by the experimenter. Further investigations at a pH value of 9 did not result in any cleaning which is further described below.

[0099] There are no de-phosphating systems known in the state of the art, which can be operated at lower temperature like room temperature or slightly elevated temperatures up to 35°C. The solution of adding at least one terpene such as orange oil to the cleaner, enables these low cleaning temperatures.2024P00070WQ I L025965PCT 13 March 16, 2026 Chemetall GmbH

[0100] EXAMPLES

[0101] The following examples further illustrate the invention but are not to be construed as limiting its scope.

[0102] Materials:

[0103] - Test specimens from practice

[0104] Part 1: Screws after pressing (before cleaning), treated with Gardobond Z 3100 (Zinc phosphating), Gardomer L 6332 / 2 (polymer lubricant) and waste oil,

[0105] Part 2: Screws after pressing (before cleaning), treated with Gardobond Z 3100 (Zinc phosphating), Gardomer L 6332 / 2 (polymer lubricant) and waste oil,

[0106] Part 3: Screws after pressing (before cleaning), treated with Gardobond Z 3100 (Zinc phosphating), Gardomer L 6332 / 2 (polymer lubricant) and waste oil,

[0107] - chemicals: 5% sodium hydroxide solution (laboratory preparation), pure orange terpenes (Carl Roth GmbH +Co. KG article no. 3098), Gardoclean S 5249 (cleaning agent mainly for the removal of phosphate and soap layers, a highly alkaline liquid cleaner that is free of silicates and borates. It is a sodium and potassium hydroxide blend formulated for cleaning, de-phosphating, and removing polymer films from steel substrates including steel strips.), Gardobond Additive H 7375 (cleaning booster based on non-ionic and anionic surfactants),

[0108] Procedure:

[0109] Cleaning tests of the screws in different cleaning media with and without the addition of surfactant or orange terpenes. Mixing ratios and application parameters can be found in the table below. After each cleaning test, the visual assessment (before / after) of the phosphate layer and polymer film cleaning on the screw head, the screw shaft and the thread is carried out, with the thread and the screw shaft presenting the greatest challenge.

[0110] Results:

[0111] In principle, the cleaning tests show that improved dephosphatisation and polymer film removal can be achieved by adding orange terpenes to a cleaning medium (sodium hydroxide solution or Gardoclean S 5249). Orange terpenes in combination with Gardoclean S 5249 and Gardobond Additive H 7375 achieved a good cleaning result within an immersion time of 2.5 minutes. In comparison, the immersion time for a combination consisting of orange terpenes, 5 % sodium hydroxide solution and Gardobond Additive H 7375 was at least 20 minutes. It should be emphasized, that the use of orange terpenes at room temperature or at 30°C provided the best cleaning results. Tests at higher temperatures (e.g. 40°C, 50°C, 70°C) showed little or no cleaning effect. This could be due to the evaporation effect of the orange terpene concentrate in the warm detergent bath. In addition, it was found that the combination of the cleaner Gardoclean S 5249 and the cleaning booster Gardobond Additive H 7275 (0.2%) already achieved good cleaning effects at 30°C and an immersion time of 2.5 minutes (test no. 30). The addition of orange terpenes resulted in better dephosphatization and polymer film removal from an orange terpene concentration of 0.1% by volume (test no. 34), from 0.25 vol-% an improvement is clearly visible (test no. 31). Increasing the concentration to 1 vol-% or 2 vol-% significantly improved the cleaning effect (tests no. 35 and 36). This is2024P00070WQ I L025965PCT 14 March 16, 2026 Chemetall GmbH

[0112] underpinned by the increased occurrence of rust on the cleaned test specimen surfaces (a higher degree of cleaning leads to the appearance of bright steel surfaces, resulting in a higher corrosion potential). The cleaning effect of the combination consisting of Gardoclean S 5249, Gardobond Additive H 7375 and orange terpenes is transferable to test specimens of different types (see tests no. 39 and 40).

[0113] Good cleaning results can only be achieved in the highly alkaline pH range (pH value approx. 13). Tests in which the pH value of a cleaner bath consisting of Gardoclean S 5249, Gardobond Additive H 7375 and orange terpenes was adjusted from approx. 13 to 9 using Gardobond Additive H 7143 did not show good dephosphatisation and polymer film removal (tests no. 41-43). In comparison, the same tests without pH value adjustment showed good cleaning (tests no. 31, 32 and 35; pH value of the solutions approx. 13).

[0114] Cleaning tests

[0115] Abbreviations:

[0116] Gardoclean S 5249 = GCS 5249

[0117] Gardobond Additive H 7375 = GBA H 7375

[0118] Orange terpene = OT

[0119] PK = test specimen

[0120] Assessment criterion:

[0121] = exceeds expectations = slightly applicable

[0122] = fully applicable = not applicable at all

[0123] = mostly applicable2024P00070WQ I L025965PCT 15 March 16, 2026 Chemetall GmbH

[0124] Table 1: Cleaning tests

[0125] Test- GCS NaOH GBA Orange- GBA VE- Temp. Time rpm piece Oil Brightening Brightening Brightening Remark

[0126] No. 5249 [wt.-%] H7375 terpene H 7143 Water [°C] [min.] removal phosphate phosphate phosphate

[0127] [wt.-%] [wt.-%] [VoL-%] for pH- layer screw layer shank layer screw

[0128] adj. head head

[0129] thread

[0130] Optical properties of the test specimen serve as reference for an effective phosphate layer and polymer film removal. The pH value of the cleaning bath is 1 15 0 0,2 0 0 70 5 300 1 13.1.

[0131] 2 0 2,5 0 0 0 70 5 300 1

[0132] 3 0 2,5 0,2 0 0 70 5 300 1

[0133] 4 0 5 0 0 0 70 5 300 1

[0134] 5 0 5 0,2 0 0 70 5 300 1

[0135] 6 0 5 0,2 0,026 0 70 5 300 1

[0136] 7 0 5 0,2 0,05 0 70 5 300 1

[0137] 8 0 5 0,2 0,075 0 70 5 300 1

[0138] 9 0 5 0,2 0,1 0 70 5 300 1

[0139] 10 0 5 0,2 0,25 0 70 5 300 1

[0140] Increase in OT concentration did not result to a significant enhancement in performance; this is likely attributable to the evaporation effect of OT at a temperature of 70°C.

[0141] 11 0 5 0,2 0,5 0 70 5 300 1

[0142] Trials at RT more 12 0 5 0,2 0,5 0 25 20 300 1 effective

[0143] Trial conducted without OT did not demonstrate

[0144]

[0145] 13 0 5 0,2 0 0 25 20 300 1 superior performance -2024P00070WQ I L025965PCT 16 March 16, 2026 Chemetall GmbH

[0146] > same trial with OT shows an improvement in cleaning efficacy. An increase in temperature did not yield a significant improvement in cleaning efficacy; trials conducted at room temperature proved to be more effective

[0147] 14 0 5 0,2 0,5 0 50 20 300 1

[0148] An increase in OT concentration did not result in a significant improvement when tested in a 5% sodium hydroxide solution. Consideration of using a different cleaning 15 0 5 0,2 1 0 25 20 300 1 framework Increase GBA H7375 no significant improvement in cleaning efficacy 16 0 5 0,4 0,5 0 25 20 500 1

[0149] Intermediate rinsing and wiping after 5 minutes -> no improvement in 17 0 5 0,4 0,5 0 25 20 500 1 cleaning efficacy 18 0 5 0,4 0 - 0 25 20 500 1

[0150] 19 0 5 0,2 0 - 0 70 20 300 1

[0151] Temperature 70°C not effective -> Tests at RT 20 0 5 0,2 0,5 0 70 20 300 1 more effective Deionised water instead of NaOH: phosphate layer remains grey. In

[0152]

[0153] 21 0 0 0,2 0 100 25 20 300 1 the tests with NaOH, the2024P00070WQ I L025965PCT 17 March 16, 2026 Chemetall GmbH

[0154] phosphate layer has a grey-brown colour. Deionised water instead of NaOH: phosphate layer remains grey. In the experiments with NaOH, the phosphate layer has a grey-brown 22 0 0 0,2 0,5 100 25 20 300 1 colour.

[0155] Tests conducted without OT and at a higher temperature (40°C) did not show improved results; same trial at room temperature was 23 0 5 0,2 0 0 40 20 300 1 more effective.

[0156] Tests conducted with OT and at a higher temperature (40°C) did not show improved results; same trial at room temperature was more effective.

[0157] 24 0 5 0,2 0,5 0 40 20 300 1

[0158] Tests at RT and lower concentration (0.5% instead of 2%) more 25 0 5 0,2 2 0 40 20 300 1 effective

[0159] lower concentration of OT (0.25 vol-% instead of 0.5 vol-%) achieves 26 0 5 0,2 0,25 0 25 20 300 1 comparable results 27 15 0 0,2 0 0 30 5 300 1

[0160] 28 15 0 0,2 0,25 0 30 5 300 1

[0161] 29 15 0 0,2 0,5 0 30 5 300 1

[0162] 30 15 0 0,2 0 0 30 2,5 300 1

[0163]

[0164] 31 15 0 0,2 0,25 0 30 2,5 300 12024P00070WQ I L025965PCT 18 March 16, 2026 Chemetall GmbH

[0165] 32 15 0 0,2 0,5 - 0 30 2,5 300 1

[0166] 33 15 0 0,2 0,05 - 0 30 2,5 300 1

[0167] Test specimen appear brighter from 0.1 vol-% 34 15 0 0,2 0,1 0 30 2,5 300 1 OT

[0168] Test specimen significantly brighter 35 15 0 0,2 1 0 30 2,5 300 1 overall

[0169] Test specimen significantly brighter 36 15 0 0,2 2 0 30 2,5 300 1 overall

[0170] 5% GCS 5249 concentration ineffective, phosphate 37 5 0 0,2 0,25 0 30 2,5 300 1 layer remains grey Cleaning effects can be seen from a 10% concentration of GCS 38 10 0 0,2 0,25 0 30 2,5 300 1 5249

[0171] Test shows reproducible results even with test 39 15 0 0,2 2 0 30 2,5 300 2 specimen 2

[0172] Test shows reproducible results even with test 40 15 0 0,2 2 0 30 2,5 300 3 specimen 3

[0173] Test comparable with test 31— > only mildly alkaline (pH 9) Phosphate layer remains grey --> Phosphate layer removal is less effective 41 15 0 0,2 0,25 x pH 9 0 30 2,5 300 1 in mild alkaline range Test comparable with trial 32 --> only mildly alkaline (pH 9)

[0174]

[0175] 42 15 0 0,2 0,5 x pH 9 0 30 2,5 300 12024P00070WQ I L025965PCT 19 March 16, 2026 Chemetall GmbH

[0176] Phosphate layer remains grey --> Phosphate layer removal is less effective in mild alkaline range Test comparable with test 35 --> only mildly alkaline (pH 9) Phosphate layer remains grey --> Phosphate layer removal is less effective

[0177]

[0178] 43 15 0 0,2 1 x pH 9 0 30 2,5 300 1 in mild alkaline range

Claims

2024P00070WQ I L025965PCT 20 March 16, 2026 Chemetall GmbHCLAIMS1. A method of cleaning of at least one metallic surface of at least one substrate, the method comprising at at least step 1) and optionally also step 2), namely1 ) contacting the at least one surface of the at least one substrate at least in portion with an aqueous alkaline composition for cleaning the substrate,wherein the aqueous alkaline composition comprises besides water at least constituents a1), a2) and a6), and optionally one or more of constituents a3) to a5), which are different from one of another, namelyat least one alkalinity inducing source as constituent a1),at least one surfactant as constituent a2) in an amount in a range of from 0.015 wt.-% to 0.060 wt.-%,optionally at least one complexing agent as constituent a3),optionally at least one decalcifying agent as constituent a4),optionally at least one alcohol as constituent a5), andat least one terpene as further constituent a6), which is unsaturated, and2) optionally rinsing the cleaned surface obtained after step 1) at least once with an aqueous rinsing composition.

2. The method according to claim 1, wherein the aqueous alkaline composition used in step 1) has a temperature in a range of from 20 to 50 °C, preferably of from 25 to 40 °C, more preferably of from 25 to 35 °C.

3. The method according to one or more of the preceding claims, characterized in that the aqueous alkaline composition used in step 1) has a pH value in a range of from >7.5 to 12.5 or <14.0, preferably of from >9 to <13.5, more preferably of from >10.0 to <13.5.

4. The method according to one or more of the preceding claims, characterized in that contacting step 1) is performed by spraying, dipping or roll coating, preferably by dipping, preferably for a period of 1 to 20 minutes, more preferably for a period of 1 to 10 minutes, still more preferably for a period of 1 to 5 minutes, yet more preferably for a period of 1 to 3 minutes.

5. The method according to one or more of the preceding claims, characterized in that the at least one terpene is present in an amount in a range of from 0.05 Vol.-% to 2.5 Vol.-%, preferably of from 0.1 Vol.- % to 2.25 Vol.-%, more preferably of from 0.15 Vol.-% to 2.0 Vol.-%, even more preferably of from 0.2 Vol.-% to 1.8 Vol.-%.2024P00070WQ I L025965PCT 21 March 16, 2026 Chemetall GmbH6. The method according to one or more of the preceding claims, characterized in that the at least one terpene being present, is selected from the group, consisting of alpha-pinene, beta-pinene, camphene, myrcene, dipentene (a racemic mixture of d- and l-forms of limonene), and orange terpene.

7. The method according to claim 6, characterized in that the at least one terpene is orange terpene.

8. The method according to one or more of the preceding claims, characterized in that optional step 2) is performed, wherein the aqueous rinsing composition used in said step 2) preferably consists or essentially consists of water only.

9. The method according to one or more of the preceding claims, characterized in thatthe at least one alkalinity inducing source being present as constituent a1) is selected from hydroxide and / or carbonate anions, and / or the at least one alkalinity inducing source being present as constituent a1) is present in an amount in a range of from 2.8 wt.-% to 6.0 wt.-%, preferably of from 3.0 wt.-% to 5.0 wt.-%, more preferably of from 4.0 wt.-% to 4.8 wt.-%, and / orthe at least one surfactant being present as constituent a2) is selected from non-ionic, anionic and / or cationic surfactants, preferably from non-ionic surfactants, and / or the at least one surfactant being present as constituent a2) is present in an amount in a range of from 0.02 wt.-% to 0.05 wt.-%, preferably of from 0.03 wt.-% to 0.04 wt.-%, and / orthe at least one complexing agent being optionally present as constituent a3) is selected from (I) carboxylic acids, salts thereof, derivatives, in particular esters, thereof, and mixtures thereof, wherein the carboxylic acids include polymeric carboxylic acids in each case, wherein the carboxylic acids include polymeric carboxylic acids in each case, is present in an amount in a range of from 2.0 wt.-% to 4.5 wt.-%, preferably of 2.5 wt.-% to 4.0 wt.-%, more preferably of from 3,0 wt.-% to 3,5 wt.-%, and / orthe at least one decalcifying agent being optionally present as constituent a4) is selected from an chelating agent chosen from EDTA or HEDP or a mixture thereof and is present in an amount in a range of from 0.05 wt.-% to 0.1 wt.-%, preferably of from 0.06 wt.-% to 0.09 wt.-% and / orthe at least one alcohol being optionally present as constituent a5) is selected from ethylene glycol or propylene glycol or a mixture thereof and is present in an amount in a range of from 0.01 wt.-% to 0.05 wt.-%, preferably of from 0.015 wt.-% to 0.03 wt.-%.

10. The method according to one or more of the preceding claims, characterized in that the aqueous alkaline composition used in step 1) contains at least 80 wt.-% of water.

11. The method according to one or more of the preceding claims, characterized in that the at least one2024P00070WQ I L025965PCT 22 March 16, 2026 Chemetall GmbHmetallic surface of the at least one substrate is at least partially made of at least one kind of steel, and that the at least one substrate is selected from fastener means like bolts, screws, tubes, nuts, rivets, pins, studs, washers.

12. An aqueous alkaline cleaning composition as defined in one or more of claims 1 to 10, which comprises besides water at least constituents a1), a2) and a6), and optionally one or more of constituents a3) to a5), which are different from one of another, namely at least one alkalinity inducing source as constituent a1), at least one surfactant as constituent a2) in an amount in a range of from 0.015 wt.-% to 0.060 wt.-%, optionally at least one complexing agent as constituent a3), optionally at least one decalcifying agent as constituent a4), optionally at least one alcohol as constituent a5), and at least one terpene as constituent a6), which is unsaturated.

13. A use of at least one terpene as constituent a6) of the aqueous alkaline composition as defined in one or more of the preceding claims, preferably when incorporated into an aqueous alkaline cleaning composition, preferably into an aqueous alkaline cleaning composition according to claim 12, for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

14. A substrate, which is a cleaned substrate being obtainable by the method according to one or more of claims 1 to 11.

15. Use of the aqueous alkaline cleaning composition according to claim 12 in a method according to one or more of claims 1 to 11 for providing an enhanced dephosphatisation and polymer film removal of metallic surfaces of substrates.

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