A method for etching at least one surface of a plastic substrate.

Abstract

The present invention relates to a method for etching at least one surface of a plastic substrate, comprising steps (A) to (C), wherein step (C) is an etching step comprising contacting with an etching composition comprising permanganate ions and phosphoric acid, each in a clearly defined concentration range.

Description

[Technical Field]

[0001] The present invention relates to a method for etching at least one surface of a plastic substrate, comprising steps (A) to (C), wherein step (C) is an etching step comprising contacting an etching composition. The etching composition each contains permanganate ions and phosphoric acid in a clearly defined concentration range. [Background technology]

[0002] The metallization of non-metallic substrates, such as plastics, has a long history in modern science and technology. Typical applications include the automotive industry and hygiene products.

[0003] However, making non-metallic / non-conductive substrates receptive to metal layers is challenging. Typically, each method begins with surface modification of the substrate surface, usually known as etching. A delicate balance is usually required to ensure sufficient surface roughening without creating excessively severe defects.

[0004] Many methods and etching compositions are known, including compositions containing environmentally problematic chromium species such as hexavalent chromium species (e.g., chromic acid). While these compositions usually provide very strong and acceptable etching results, there is an increasing demand for environmentally friendly alternatives, some of which have already been provided in the art. In many cases, manganese-based etching compositions are used instead.

[0005] For example, European Patent Application Publication No. 2025708 relates to a manganese-containing etching composition containing phosphoric acid.

[0006] U.S. Patent No. 3,647,699 relates to a surface modifier composition for ABS resin. The composition contains orthophosphoric acid and permanganate ions.

[0007] U.S. Patent No. 9,023,228 relates to a method for pickling plastic surfaces, including pickling solutions and oxidation cells.

[0008] European Patent Application Publication No. 1001052 relates to a method for metallizing the surface of a resin. The method includes the step of contacting a substrate with a mild etching solution containing permanganate and phosphoric acid and / or sulfuric acid.

[0009] Obtaining an etching result very similar to or even identical to chromic acid etching is a highly desirable goal. However, it is not easy to achieve. Even though the chemical etching is mostly the same, more steps are often required to achieve it compared to the previously used chromic acid etching. In that case, a simple replacement of the prior art with the new one cannot be easily done. For example, additional space in the facility is very often required to accommodate additional tanks and rinsing lines. Therefore, there is a continuing need to further improve known manganese-based etching compositions and their respective etching processes.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, an object of the present invention is to overcome the above-mentioned drawbacks of the prior art.

[0012] In particular, an object of the present invention is to provide a method for etching at least one surface of a plastic substrate that can be easily implemented on an existing plating line and can provide an etching result extremely similar to the etching result obtained from a chromic acid etching composition.

[0013] Another object is that the etched substrate can be flexibly used in a variety of subsequent metallization processes.

[0014] A further object of the present invention is to enable selective etching of only other components without etching PC on a two-component substrate (i.e., a 2K substrate) where one component is preferably polycarbonate (PC), more preferably transparent / translucent PC.

Means for Solving the Problems

[0015] The above object is a method for etching at least one surface of a plastic substrate, comprising: (A) a step of preparing a substrate; (B) optionally, a step of contacting the prepared substrate with one or more pretreatment compositions; (C) a step of contacting the substrate obtained after step (A) or (B) with an etching composition to produce an etched substrate The etching composition comprises: (a) water; (b) permanganate ions at a concentration of 0.0025 mol / L to 0.1 mol / L; (c) phosphoric acid at a concentration of 7 mol / L to 12 mol / L; (d) silver (I) ions at a concentration of 0 to 0.1 mol / L; and (e) manganese (II) ions at a concentration of 0 or less than 10 ppm and at least a part of the permanganate ions is converted to a manganese species having an oxidation number less than +7, at least during step (C).

[0016] In relation to the present invention, the concentration in mol / L or mmol / L is based on the total volume of the etching composition unless otherwise specified.

[0017] Our own experiments have shown that the method of the present invention produces etching patterns that are very similar to, or even identical to, those obtained with chromate etching compositions (see examples below in this specification).

[0018] Furthermore, the inventors' experiments have shown that the method of the present invention can easily replace existing chromic acid etching lines because it generally avoids the swelling step that precedes the etching process. In many cases, this means that each compartment / container / tank is not required in each plating line.

[0019] In addition, the method of the present invention allows for high flexibility in how the subsequent metallization process proceeds. Substrates etched by the method of the present invention can be further metallized with nickel (e.g., Watt nickel) or with immersion copper (sometimes called "substitution plating," in this particular case where a less noble metal is replaced with more electrochemically active copper without the use of a reducing agent). These two metallization options cover a wide range of possible applications.

[0020] Another important benefit of the method of the present invention is selectivity. Our own experiments have shown that the etching composition used in the method of the present invention enables selective etching of 2K substrates containing PC. In such cases, PC is not etched, but other components, such as acrylonitrile butadiene styrene (ABS) or acrylonitrile butadiene styrene-polycarbonate (ABS-PC), are etched.

[0021] All of these advantages were unexpected and therefore surprising. However, they are only achieved if the aforementioned concentration ranges for permanganate ions and phosphate are maintained. [Modes for carrying out the invention]

[0022] The method of the present invention primarily involves contacting a plastic substrate with a specific pre-etching composition to obtain a sufficiently etched plastic substrate.

[0023] Step (A): Prepare the substrate: In step (A), the substrate is prepared.

[0024] The present invention is preferable in which the plastic substrate contains a butadiene portion, preferably polybutadiene.

[0025] Furthermore, a method of the present invention in which the plastic substrate includes a nitrile portion is also preferred.

[0026] Furthermore, a method of the present invention in which the plastic substrate includes an acrylic portion is also preferred.

[0027] Furthermore, a method of the present invention in which the plastic substrate includes a styrene portion is also preferred.

[0028] The method of the present invention is more preferable in which the substrate in step (A) comprises acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene-polycarbonate (ABS-PC), polypropylene (PP), polyamide (PA), polyetherimide (PEI), polyetherketone (PEK), epoxy resin, mixtures thereof, or composites thereof.

[0029] The method of the present invention is preferred in which polyetherketone (PEK) comprises polyaryletherketone (PAEK), polyetheretherketone (PEEK), polyetheretheretherketone (PEEEK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), polyetherketoneketone (PEKK), and / or mixtures thereof, preferably polyetheretherketone (PEEK), polyaryletherketone (PAEK), and / or mixtures thereof.

[0030] In some cases, the method of the present invention is highly preferred in which the substrate comprises a two-component (2K) substrate, preferably containing polycarbonate (PC) as one component. Preferred 2K substrates include polycarbonate / acrylonitrile butadiene styrene-polycarbonate (PC / ABS-PC) and / or polycarbonate / acrylonitrile butadiene styrene (PC / ABS). The etching composition used in the method of the present invention selectively etches ABS and ABS-PC without etching the PC component.

[0031] In some cases, a 2K substrate in which one component is transparent is preferred, and it is preferable that the 2K substrate contains transparent polycarbonate (PC).

[0032] Step (B): If applicable, the prepared substrate is brought into contact with one or more pretreatment compositions: In many cases, the method of the present invention, in which contact is performed, i.e., is not optional, is preferred.

[0033] In step (B), the method of the present invention is preferable in which one or more pretreatment compositions include a cleaning composition.

[0034] One or more pretreatment compositions preferably used in the method of the present invention contain water. Most preferably, water is the sole solvent in the one or more pretreatment compositions.

[0035] The method of the present invention in which step (B) does not include a swelling step is preferred. Therefore, the method of the present invention in which one or more pretreatment compositions do not include a swelling composition is preferred.

[0036] Therefore, the method of the present invention is preferable in which the substrate is not swollen in step (C).

[0037] In step (B), one or more pretreatment compositions do not contain gamma-butyrolactone, preferably lactone-free, in the method of the present invention.

[0038] In step (B), one or more pretreatment compositions do not contain 2-butoxyethanol (i.e., ethylene glycol monobutyl ether, EGBE), preferably ether-free, which is preferable to the method of the present invention.

[0039] In step (B), the method of the present invention is preferable in which one or more pretreatment compositions do not contain organic alcohols (preferably not), and preferably do not contain organic solvents (preferably not).

[0040] The method of the present invention is preferable in which step (B) does not include a step of contacting with a pretreatment composition containing an organic solvent, preferably a step of contacting with an organic solvent-pretreatment composition.

[0041] The specific organic solvents and general organic solvents mentioned above are typically used for swelling. However, in the present invention, such swelling steps or swelling chemicals are not required to obtain a sufficiently etched substrate. Therefore, these steps are preferably omitted, and most preferably omitted in substrates containing ABS.

[0042] Step (C): The substrate obtained after step (A) or (B) is brought into contact with the etching composition to produce an etched substrate: In step (C) of the method of the present invention, the prepared substrate or pre-treated substrate is brought into contact with the etching composition.

[0043] Etching composition used in the method of the present invention (a) water, (b) Permanganate ions in concentrations of 0.0025 mol / L to 0.1 mol / L, (c) 7 mol / L to 12 mol / L phosphoric acid, (d) 0-0.1 mol / L of silver(I) ions, and (e) Manganese(II) ions less than 0 or 10 ppm Includes.

[0044] The method of the present invention is preferred in which (a), (b), (c), (d), and (e) form 90 wt.-% or more, preferably 92 wt.-% or more, more preferably 94 wt.-% or more, even more preferably 96 wt.-% or more, and most preferably 98 wt.-% or more of the total mass of the aqueous etching composition.

[0045] The method of the present invention is preferable in which the etching composition substantially does not contain methanesulfonic acid and its salts, preferably not, preferably substantially does not contain C1-C4 alkylsulfonic acid and its salts, preferably not, most preferably substantially does not contain C1-C4 sulfonic acid and its salts, preferably not.

[0046] The method of the present invention is preferable in which the etching composition is substantially free of bromide and iodide anions, preferably substantially free of chloride, bromide, and iodide anions, preferably substantially free of halogen anions, most preferably substantially free of halide anions.

[0047] The method of the present invention is preferable in which the etching composition substantially does not contain trivalent chromium ions and hexavalent chromium compounds, preferably none, and preferably substantially does not contain any compounds and ions containing chromium.

[0048] The present invention is preferable in which the etching composition substantially does not contain sulfuric acid, preferably in a manner that does not contain sulfuric acid.

[0049] The method of the present invention is preferred in which the total concentration of manganese(II) ions in the etching composition is zero in step (C). This is most preferred. However, in some cases the total concentration is preferred (and also acceptable) in the range of 0.1 ppm to 9 ppm, preferably 0.5 ppm to 8 ppm, more preferably 1 ppm to 7 ppm, even more preferably 1.5 ppm to 6 ppm, and most preferably 2 ppm to 5 ppm, based on the total mass of the etching composition.

[0050] The present invention is more preferable in which, in step (C), the manganese(II) ion concentration in the etching composition is 9 ppm or less, preferably 8 ppm or less, more preferably 7 ppm or less, even more preferably 6 ppm or less, and most preferably 5 ppm or less.

[0051] Generally, manganese(II) ions are an undesirable byproduct of the method of the present invention.

[0052] In the presence of phosphoric acid, permanganate ions are typically unstable and decompose into manganese species with oxidation states below +7. My own experiments have shown that the decomposition rate is strongly dependent on the concentration of phosphoric acid. This decomposition becomes even stronger when permanganate ions oxidize chemical compounds in the substrate to etch the substrate surface. As a result, at least a portion of the permanganate ions are further converted into manganese species with oxidation states below +7.

[0053] In order to carry out the method of the present invention continuously, new or fresh permanganate ions must be added, i.e., replenished. Therefore, the method of the present invention carried out continuously is preferred. This is most preferably applied to all steps defined in the present invention.

[0054] Process (C) (C-1) A step to replenish the etching composition used in step (C) with permanganate ions. The present invention method, which includes the above, is preferred.

[0055] Typically, there are more than one way to carry out the method of the present invention in a continuous manner.

[0056] In some cases, reoxidation of permanganate species having an oxidation state of less than +7 is preferably applied, more preferably chemically (chemical reoxidation) or by applying an external electric current (electrolytic reoxidation). In this way, permanganate ions are recycled and preferably replenished and reused.

[0057] In many cases - At least a part of the manganese species having an oxidation number of less than +7 is treated in the regeneration section, and a current is applied to re-oxidize the manganese species to permanganate ions, - The permanganate ions replenished in step (C-1) are those re-oxidized in the regeneration section The method of the present invention is preferred.

[0058] This technique is most preferred.

[0059] The current is preferably 0.1 A / dm 2 ~10 A / dm 2 , preferably 0.2 A / dm 2 ~7.5 A / dm 2 , more preferably 0.3 A / dm 2 ~5 A / dm 2 , even more preferably 0.4 A / dm 2 ~2.5 A / dm 2 , most preferably 0.5 A / dm 2 ~1 A / dm 2 The method of the present invention which is a direct current having a current density in the range is preferred. 0.1 A / dm 2 ~2 A / dm 2 , more preferably 0.2 A / dm 2 ~1 A / dm 2 , most preferably 0.3 A / dm 2 ~0.8 A / dm 2 The current density in the range is very preferred.

[0060] The method of the present invention in which the manganese species having an oxidation number of less than +7 is treated in the regeneration section at a temperature in the range of 20°C to 65°C, preferably 25°C to 60°C, more preferably 30°C to 55°C, most preferably 35°C to 50°C, and even most preferably 37°C to 43°C is preferred.

[0061] In some other cases, a portion of the etching composition is removed and a portion of fresh, solubilized permanganate ions is replenished (often referred to as a "bleed-and-feed" approach). However, this approach generates a considerable amount of waste if the removed etching bath components are not recirculated. While this approach is technically possible, it is less desirable in relation to the present invention.

[0062] Therefore, in some cases - By removing at least a portion of the etching composition, at least a portion of the manganese species having an oxidation state of less than +7 is removed from the etching composition. - The permanganate ions replenished in step (C-1) originate from alkaline permanganate. The method of the present invention is preferred.

[0063] The present invention is preferable in which the etching composition is strongly acidic and has a pH of preferably 2 or less, more preferably 1 or less, even more preferably 0.5 or less, and most preferably zero or less.

[0064] The etching composition used in the method of the present invention contains water.

[0065] The present invention is preferred in which the remainder of the etching composition is water. Preferably, the water has a concentration in the range of 10.8 mol / L to 27.5 mol / L, preferably 12 mol / L to 26 mol / L, more preferably 13.1 mol / L to 24.5 mol / L, even more preferably 13.9 mol / L to 23.3 mol / L, and most preferably 14.7 mol / L to 22.6 mol / L.

[0066] The method of the present invention is preferable in which the etching composition contains permanganate ions in the range of 0.004 mol / L to 0.09 mol / L, preferably 0.005 mol / L to 0.075 mol / L, more preferably 0.006 mol / L to 0.06 mol / L, even more preferably 0.007 mol / L to 0.045 mol / L, even more preferably 0.008 mol / L to 0.03 mol / L, and most preferably 0.009 mol / L to 0.019 mol / L.

[0067] The method of the present invention is highly preferable in which the permanganate ion concentration in the etching composition is in the range of 0.004 mol / L to 0.02 mol / L, preferably 0.005 mol / L to 0.019 mol / L, more preferably 0.006 mol / L to 0.017 mol / L, even more preferably 0.007 mol / L to 0.015 mol / L, and most preferably 0.008 mol / L to 0.013 mol / L. While these specific concentration ranges provide optimal etching results, a wider concentration range is basically possible. These highly preferred ranges are most preferable when a regeneration section and current are applied in step (C-1), i.e., in electrolytic reoxidation. When a regeneration section and current are applied, it is generally preferable that the permanganate ion concentration in the etching composition does not exceed 30 mmol / L, preferably not exceeding 27 mmol / L, more preferably not exceeding 24 mmol / L, even more preferably not exceeding 21 mmol / L, most preferably not exceeding 18 mmol / L, and most preferably not exceeding 15 mmol / L. This is most preferably applied in combination with the lower limit mentioned earlier.

[0068] The method of the present invention is preferable in which the phosphoric acid in the etching composition has a concentration in the range of 7.4 mol / L to 11.8 mol / L, preferably 7.8 mol / L to 11.5 mol / L, more preferably 8.2 mol / L to 11.2 mol / L, even more preferably 8.5 mol / L to 11 mol / L, and most preferably 8.7 mol / L to 10.8 mol / L.

[0069] The present invention is most preferable in which phosphoric acid is the only acid in the etching composition.

[0070] In some cases, the method of the present invention is preferred in which the etching composition contains phosphoric acid in a concentration in the range of 9.8 mol / L to 11.2 mol / L, preferably 10 mol / L to 11 mol / L, and more preferably 10.3 mol / L to 10.7 mol / L. This is particularly preferred in the "feed and bleed" approach.

[0071] In other cases, the method of the present invention is preferred in which the etching composition contains phosphoric acid in a concentration of 9.2 mol / L to 10.5 mol / L, preferably 9.3 mol / L to 10.4 mol / L, and more preferably 9.4 mol / L to 10.3 mol / L. This is particularly preferred by a reoxidation method, most preferably electrolytic reoxidation.

[0072] In some cases, the method of the present invention is preferred in which the etching composition contains silver(I) ions. This is most preferred in electrolytic reoxidation, if a reoxidation technique is used. Silver ions are preferably required to better catalyze electrolytic reoxidation. However, silver(I) ions do not disrupt the "feed and bleed" approach.

[0073] The method of the present invention is preferable in which the etching composition contains silver(I) ions in a concentration in the range of 0.0001 mol / L to 0.09 mol / L, preferably 0.0002 mol / L to 0.07 mol / L, more preferably 0.0005 mol / L to 0.05 mol / L, even more preferably 0.0007 mol / L to 0.03 mol / L, most preferably 0.001 mol / L to 0.01 mol / L, and most preferably 0.0015 mol / L to 0.005 mol / L.

[0074] The method of the present invention is preferred in which silver(I) ions in the etching composition are provided in step (C) through a silver(I) salt and / or a soluble silver anode.

[0075] Preferred silver(I) salts include AgNO3, Ag2CO3, Ag3PO4, AgOH, Ag2O, and / or Ag2SO4.

[0076] As mentioned above, during step (C) in particular, the etching composition contains not only permanganate ions but also manganese species with oxidation states of less than +7. All of these together form the total manganese concentration.

[0077] The method of the present invention is preferable in which, when all manganese species in the etching composition are combined, the total concentration is in the range of 0.02 mol / L to 0.3 mol / L, preferably 0.03 mol / L to 0.25 mol / L, and most preferably 0.035 mol / L to 0.2 mol / L, based on the total volume of the etching composition. Most preferably, all manganese species in the etching composition are combined to have a total concentration in the range of 0.04 mol / L to 0.1 mol / L. This is very preferable when combined with electrolytic reoxidation. In the present invention, it is very beneficial if the total concentration of all manganese species combined remains relatively stable in the case of electrolytic reoxidation. In fact, manganese species are not usually added to maintain the method, except for replenishing the extracted manganese species. This usually stabilizes the entire method of the present invention.

[0078] In step (C), the etching composition is 1.15 g / cm³ at a temperature of 25°C. 3 ~1.51 g / cm³ 3 Preferably 1.22 g / cm³ 3 ~1.41 g / cm³ 3 , more preferably 1.24 g / cm³ 3 ~1.39 g / cm³ 3 Most preferably 1.26 g / cm³ 3 ~1.38 g / cm³ 3 The present invention method having a density within the range of is preferred.

[0079] The present invention is preferable in which the etching composition further comprises one or more surfactants. Surfactants are typically required to increase wetting properties. There are no particular restrictions on the type of surfactant. Therefore, cationic surfactants, anionic surfactants, and / or nonionic surfactants are preferred.

[0080] The method of the present invention is preferable in which one or more surfactants are present in the etching composition at a total concentration in the range of 0.001 g / L to 1.0 g / L, preferably in the range of 0.005 g / L to 0.7 g / L, more preferably in the range of 0.01 g / L to 0.5 g / L, even more preferably in the range of 0.02 g / L to 0.3 g / L, and most preferably in the range of 0.03 g / L to 0.15 g / L, based on the total volume of the etching composition.

[0081] However, the method of the present invention is preferable in which the etching composition substantially does not contain, preferably does not contain, fluorinated surfactants, and preferably substantially does not contain, preferably fluorinated organic compounds. As environmental regulations become increasingly stringent, fluorinated organic compounds, in particular fluorinated surfactants, are less desirable.

[0082] The etching composition used in the method of the present invention is preferably composed of an alkaline permanganate, preferably sodium permanganate and / or potassium permanganate, preferably sodium permanganate. If a "feed-and-bleed" approach is used, such permanganates are also preferably used to replenish permanganate ions. However, theoretically, the etching composition can be composed using only manganese(II) salts, and the manganese(II) ions can be reoxidized in a regeneration compartment to obtain an etching composition that can be used in the method of the present invention. However, this is not very preferable.

[0083] The present invention is preferable in which the etching composition contains alkali ions, most preferably sodium ions, in a total amount in the range of 0.002 mol / L to 0.5 mol / L, preferably 0.004 mol / L to 0.3 mol / L, based on the total volume of the etching composition.

[0084] The method of the present invention is preferable in which the etching composition is at a temperature in the range of 25°C to 60°C, preferably 28°C to 55°C, more preferably 30°C to 50°C, even more preferably 32°C to 48°C, and most preferably 35°C to 45°C during step (C).

[0085] The present invention is preferable in which step (C) is carried out for a time in the range of 1 to 120 minutes, preferably 3 to 90 minutes, more preferably 5 to 70 minutes, even more preferably 6 to 50 minutes, and most preferably 7 to 35 minutes.

[0086] In some cases, the method of the present invention is preferred in which step (C) is carried out for a time in the range of 1 to 90 minutes, preferably 2 to 70 minutes, more preferably 3 to 50 minutes, even more preferably 4 to 30 minutes, and most preferably 5 to 20 minutes. This is very preferred if electrolytic reoxidation is applied.

[0087] In step (C), if the substrate preferably contains acrylonitrile-butadiene-styrene (ABS) and / or acrylonitrile-butadiene-styrene-polycarbonate (ABS-PC), the method of the present invention is preferred in which, firstly, polybutadiene is pretreated, preferably etched, and most preferably more pretreated, and preferably etched, than polybutadiene-acrylonitrile styrene.

[0088] A preferred method of the present invention is one in which substantially no, preferably none, manganese dioxide (MnO2) precipitates on the etched substrate during step (C). Therefore, in the method of the present invention, a step is not required (and therefore not applied) to reduce manganese dioxide on the etched substrate; i.e., to dissolve MnO2 by chemical reduction using a reducing agent. Therefore, preferably, the etched substrate is not brought into contact with the respective composition containing the reducing agent after step (C). Due to the specific composition of the etching composition and how it is used in the method of the present invention, such a step is not required. Typical rinsing with water is sufficient. In this regard, the number of steps can be further reduced, and as a result, the method of the present invention can in many cases better replace commonly used chromic acid etching lines.

[0089] Therefore, the method of the present invention is preferable, which further includes rinsing with water after step (C), more preferably with water that does not contain a reducing agent capable of chemically reducing manganese dioxide.

[0090] Further steps: After step (C), i.e., after etching the substrate, metallization usually follows.

[0091] Furthermore, after process (C), (D) A step of bringing the etched substrate into contact with an activating composition to obtain an activated substrate; and / or (preferably and) (E) A step of bringing an etched substrate or an activated substrate (preferably an activated substrate) into contact with a first metallization composition to deposit a first metal or metal alloy layer on the substrate to produce a first metallized substrate. The present invention method, which includes the above, is preferred.

[0092] In this regard, the method of the present invention is preferably a method for activating at least one surface of a plastic substrate, and each method for metallizing at least one surface of a plastic substrate.

[0093] In the method of the present invention, preferably, step (D) is an independent step separated from step (C). In other words, the etching composition used in step (C) is not the activating composition used in step (D).

[0094] In step (D) of the method of the present invention, the etched substrate is brought into contact with the activating composition.

[0095] In step (D), the preferred method of the present invention is one in which the activating composition comprises palladium, preferably dissolved palladium ions or colloidal palladium, most preferably colloidal palladium. Preferably, the colloidal palladium contains tin.

[0096] The method of the present invention is preferable in which the activating composition in step (D) contains palladium in a total concentration range of 20 mg / L to 200 mg / L, preferably 40 mg / L to 150 mg / L, more preferably 50 mg / L to 110 mg / L, and most preferably 55 mg / L to 80 mg / L, based on the total volume of the activating composition. Preferably, this total concentration includes both dissolved palladium ions and colloidal palladium. The above concentrations are based on elemental palladium.

[0097] The method of the present invention is preferable in which the activating composition is at a temperature in the range of 25°C to 70°C, preferably 30°C to 60°C, more preferably 36°C to 50°C, and most preferably 39°C to 46°C in step (D).

[0098] The method of the present invention is preferable in which the contact in step (D) is carried out for a time in the range of 1 to 15 minutes, preferably 2 to 12 minutes, more preferably 3 to 9 minutes, and most preferably 4 to 7 minutes.

[0099] Process (D) (D-1) A step of modifying the activated substrate by contacting it with an accelerator composition. The present invention method, which includes the accelerator composition, is preferred. - If the activating composition in step (D) contains colloidal palladium, it does not contain a reducing agent but contains at least one complexing agent for tin ions, or - If the activating composition in step (D) contains palladium ions but does not contain colloidal palladium, it contains a reducing agent for reducing the palladium ions to metallic palladium.

[0100] In step (D-1), the accelerator composition does not contain a reducing agent but contains at least one complexing agent for tin ions, is acidic, and preferably further contains sulfuric acid.

[0101] In the present invention, the above-defined step (D-1) is performed after the etched substrate is brought into contact with the activating composition to obtain an activated substrate.

[0102] In step (E) of the method of the present invention, an etched substrate or an activated substrate is brought into contact with a first metallization composition to deposit a first metal or metal alloy layer thereon to obtain a first metallized substrate.

[0103] Therefore, step (E) is either applied to the etched substrate as a direct metallization following the activation of step (D), or without activation. In the latter case, step (D) is not necessary. However, the method of the present invention that carries out steps (D) and (E) is preferred.

[0104] In step (E), the first metallization composition preferably contains nickel ions and a reducing agent for reducing the nickel ions, and as a result, the first metal or metal alloy layer is preferably nickel or a nickel alloy layer. Therefore, the first metallized substrate is preferably a first nickel or nickel alloy metallized substrate.

[0105] In step (E), the preferred method of the present invention is one in which the first metallization composition is alkaline, preferably having a pH in the range of 8.0 to 11.0, preferably 8.2 to 10.2, more preferably 8.4 to 9.3, and most preferably 8.6 to 9.0. However, in some rare cases, the preferred method of the present invention is one in which the first metallization composition in step (E) is instead acidic, preferably weakly acidic, and most preferably having a pH in the range of 6 to 6.9.

[0106] The method of the present invention is preferable in which the first metallized composition is heated in step (E) to a temperature in the range of 18°C ​​to 60°C, preferably 20°C to 55°C, more preferably 23°C to 50°C, and most preferably 26°C to 45°C.

[0107] Preferably, the first metallized substrate is subsequently further metallized.

[0108] Furthermore, after step (D) or (E), (F) A step of bringing an activated substrate or a first metallized substrate into contact with a second metallization composition to precipitate a second metal or metal alloy layer on the substrate and produce a second metallized substrate. The present invention method, which includes the above, is preferred.

[0109] If step (F) follows step (D), then step (E) is preferably omitted, and the second metallized composition is essentially equivalent to the first metallized composition. However, this is not very preferable. More preferably, steps (E) and (F) are carried out consecutively. This does not exclude the rinsing step.

[0110] Most preferably, step (F) allows for a high degree of flexibility in how it proceeds specifically. This is a major advantage of the method of the present invention. At least two alternatives are possible.

[0111] In the first alternative, the method of the present invention is preferred, wherein in step (F), the second metallization composition contains copper ions at a concentration in the range of 0.002 mol / L to 0.4 mol / L, more preferably in the range of 0.004 mol / L to 0.25 mol / L, even more preferably in the range of 0.005 mol / L to 0.1 mol / L, and most preferably in the range of 0.007 mol / L to 0.04 mol / L, based on the total volume of the second metallization composition. Most preferably, the copper ions are copper(II) ions.

[0112] The method of the present invention in the first alternative means is more preferable in which the second metallization composition is acidic and preferably has a pH of 2 or less, preferably 1 or less.

[0113] The method of the present invention in the first alternative means is more preferable in which the second metallization composition comprises at least one acid, preferably at least one inorganic acid, more preferably at least sulfuric acid. Preferably, at least one acid (more preferably at least one inorganic acid, most preferably at least sulfuric acid) has a total concentration in the range of 0.001 mol / L to 0.5 mol / L, preferably in the range of 0.003 mol / L to 0.3 mol / L, more preferably in the range of 0.005 mol / L to 0.1 mol / L, and most preferably in the range of 0.007 mol / L to 0.07 mol / L, based on the total volume of the second metallization composition.

[0114] The method of the present invention in the first alternative means is more preferable if the second metallization composition has a temperature in the range of 20°C to 50°C, preferably in the range of 22°C to 45°C, more preferably in the range of 24°C to 40°C, and most preferably in the range of 25°C to 35°C.

[0115] The method of the present invention in the first alternative means is more preferable in which the second metallization composition substantially, preferably, does not contain a reducing agent for copper ions.

[0116] The method of the present invention in the first alternative means, where the second metallization composition is an immersion copper composition, is most preferred. Therefore, copper ions are not reduced to metallic copper by the reducing agent. This is also known as substitution plating.

[0117] In the second alternative, the method of the present invention is preferred in which the second metallization composition contains nickel ions in step (F).

[0118] The method of the present invention is more preferable in a second alternative means in which the second metallization composition substantially, preferably without, a reducing agent for nickel ions.

[0119] The method of the present invention in a second alternative means is more preferable, where the second metallization composition is acidic and has a pH in the range of preferably 1.0 to 5.0, preferably 2.0 to 4.5, more preferably 2.8 to 4.0, and most preferably 3.3 to 3.7.

[0120] The method of the present invention in a second alternative means is more preferable, wherein the second metallization composition has a temperature in the range of 25°C to 70°C, preferably 35°C to 65°C, more preferably 45°C to 61°C, and most preferably 52°C to 58°C.

[0121] The method of the present invention in a second alternative means is more preferable, in which the contact is carried out for a time in the range of 1 to 10 minutes, preferably 2 to 8 minutes, and most preferably 2.5 to 5.5 minutes.

[0122] A current of 0.3 A / dm² is preferred. 2 ~10.0A / dm 2 The range is preferably 0.5 A / dm 2 ~8.0A / dm 2 In the range of 0.8 A / dm 2 ~6.0A / dm 2 Within the range of 1.0 A / dm 2 ~4.0A / dm 2 The range is most preferably 1.3 A / dm 2 ~2.5A / dm 2 The method of the present invention is more preferable in a second alternative means applied within the range of . Therefore, the second alternative means is preferably electrolytic nickel deposition.

[0123] The method of the present invention is more preferable in a second alternative means in which the second metallization composition contains chloride ions and / or (preferably) boric acid.

[0124] The method of the present invention in a second alternative means in which the second metallization composition is a Watt nickel composition is most preferred. Accordingly, the method of the present invention in a second alternative means in which the second metallization composition contains chloride ions, sulfate ions, and boric acid is preferred.

[0125] After step (F), the second metallized substrate is preferably further metallized.

[0126] Furthermore, after step (F), (G) A step of bringing a second metallized substrate into contact with a third metallized composition to deposit a third metal or metal alloy layer onto the substrate by electrolysis to produce a third metallized substrate. The present invention method, which includes the above, is preferred.

[0127] The method of the present invention is preferable in which the third metallization composition contains copper ions at a concentration preferably in the range of 0.05 mol / L to 3 mol / L, more preferably in the range of 0.1 mol / L to 2 mol / L, even more preferably in the range of 0.2 mol / L to 1.5 mol / L, and most preferably in the range of 0.3 mol / L to 1 mol / L, based on the total volume of the third metallization composition.

[0128] The present invention is preferable in which an electric current, preferably DC, is applied in step (G).

[0129] The method of the present invention is more preferable in which the third metallization composition is acidic or alkaline. In this regard, the acidic third metallization composition represents the first alternative; the alkaline third metallization composition represents the second alternative, and in the present invention, the first alternative is more preferable because it provides very good results with a plastic substrate.

[0130] The method of the present invention is more preferable in which the third metallization composition according to the first alternative means has a pH of 2 or less, preferably 1 or less.

[0131] The method of the present invention is more preferable in which the third metallization composition according to the first alternative means comprises at least one acid, preferably at least one inorganic acid, most preferably at least sulfuric acid. Preferably, at least one acid (more preferably at least one inorganic acid, most preferably at least sulfuric acid) has a total concentration in the range of 0.1 mol / L to 5 mol / L, preferably in the range of 0.2 mol / L to 3 mol / L, more preferably in the range of 0.3 mol / L to 2 mol / L, and most preferably in the range of 0.4 mol / L to 1.5 mol / L, based on the total volume of the second metallization composition.

[0132] The method of the present invention is more preferable in which the third metallization composition according to the first alternative means contains chloride ions, preferably in a total concentration of 500 mg / L or less, preferably 300 mg / L or less, and most preferably 150 mg / L or less.

[0133] The method of the present invention is more preferable in which the third metallization composition according to the first alternative means has a temperature in the range of 20°C to 49°C, preferably in the range of 22°C to 43°C, more preferably in the range of 24°C to 39°C, and most preferably in the range of 26°C to 35°C.

[0134] The method of the present invention is more preferable if the third metallization composition according to the second alternative means has a pH in the range of 7.1 to 12, preferably in the range of 7.4 to 11, and most preferably in the range of 7.6 to 10.

[0135] The method of the present invention is more preferable in which the third metallization composition according to the second alternative means comprises cyanide ions or pyrophosphate ions, preferably pyrophosphate ions.

[0136] The method of the present invention is more preferable in which the third metallization composition according to the second alternative means has a temperature in the range of 50°C to 70°C.

[0137] In this invention, the terms 1, 2, and 3, "metallized substrate," refer to the corresponding steps as defined herein, not to the quantity / number of metallized substrates.

[0138] The present invention is preferable in which, after step (G), the third metallized substrate is brought into contact with one or more further metallization compositions, at least one of which contains trivalent chromium ions, resulting in the deposition of a metallic layer of chromium or a chromium alloy, respectively.

[0139] Most preferably, the chromium or chromium alloy metal layer is the outermost metal layer. Therefore, most preferably, the method of the present invention metallizes a plastic substrate, and the metallization includes chromium deposition, preferably decorative chromium deposition.

[0140] In the present invention, a series of steps, particularly a metallization step, is preferably defined. Preferably, this does not exclude intermediate steps, such as rinsing steps, between those steps. Therefore, the method of the present invention is preferred in which an intermediate step, most preferably a rinsing step, is performed between at least one of steps (B), (C), and preferably one of (D) to (G). [Examples]

[0141] Herein, the present invention is illustrated by the following non-limiting embodiments.

[0142] In step (A) of the method of the present invention, a plurality of nonmetallic plastic substrates (ABS and ABS-PC, each 0.1 dm 2 ~10dm 2 (Using surface dimensions within the range of)

[0143] Before contacting the substrate with the etching composition, it was pre-treated in step (B) by contacting it with a cleaning solution (Uniclean 151, a product of Atotech). Neither swelling nor a swelling composition was used, nor was it necessary. Thus, there was no contact with organic solvents.

[0144] After step (B), the pre-treated substrate was rinsed and then etched in step (C) with the respective etching compositions (40°C) summarized in Table 1.

[0145] After step (C), an etching pattern was obtained and further examined under a microscope. It showed a sponge-like structure that was extremely similar to a typical etching pattern obtained after etching with chromic acid. Our own analysis confirmed that the polybutadiene skeleton in the substrate was mainly etched, while the acrylonitrile styrene of the substrate remained almost entirely intact.

[0146] After step (C), rinsing with water was performed. Even if manganese species remained on the surface of the substrate, their strong adhesive force (including manganese dioxide) was not observed, so the manganese species were easily rinsed off with water.

[0147] In step (D), the etched substrate was brought into contact with an activating composition containing colloidal palladium (approximately 50 mg / L Pd, at a temperature of 40°C, for a contact time of 5 minutes) to obtain an activated substrate.

[0148] It was rinsed with water before step (E).

[0149] In step (E), the activated and rinsed substrate was brought into contact with the first metallization composition to obtain the first metallized substrate. The activated substrate was brought into contact with the first metallization composition (temperature approximately 26°C to 45°C; contact time approximately 10 minutes) which is alkaline (pH approximately 8.6 to 9.0) for electroless nickel plating. The first metallization composition contained approximately 3.5 g / L of nickel ions and approximately 15 g / L of hypophosphate ions as a reducing agent for the nickel ions, and a nickel alloy metallized substrate was obtained.

[0150] In step (F), the nickel alloy-metallized substrate is treated with nickel sulfate, nickel chloride, and boric acid (Watt-nickel composition; pH approximately 3.3-3.7; temperature 55°C, current density approximately 1.5 A / dm²). 2The material was then brought into contact with a second acidic metallization composition containing either nickel or copper sulfate and sulfuric acid (electroless metallization without reducing agent, immersion copper composition; pH < 1) for approximately 0.5 to 5 minutes. Thus, step (F) is electrolytic deposition of nickel or electroless immersion deposition of copper (copper substitution plating). Both were tested on most substrates (see Table 1 below).

[0151] Subsequently, the second metallized substrate having a second metal or metal alloy layer was rinsed with water.

[0152] In step (G), after rinsing, each substrate was brought into contact with a third metallization composition (acidic pH) to obtain a third metallized substrate having a copper layer with a thickness of more than 30 μm (contact time approximately 45 minutes, 32.5°C, 40 g / L copper ions; electrolytic copper plating).

[0153] Next, a further metallization process was carried out to deposit a chromium layer. The metallized substrate, which had a copper layer with a thickness of more than 30 μm, was subjected to nickel plating at least one more time.

[0154] In the final metallization step, each substrate was brought into contact with a further metallization composition to obtain a metallized substrate having a chromium layer. This further metallization composition contained 15 g / L to 30 g / L of trivalent chromium and boric acid (acidic pH, 25°C to 60°C).

[0155] Finally, the optical quality of the chromium layer was evaluated by analyzing its coverage and optical defects, particularly blistering. The results showed no haze or other optical defects, especially blistering. In particular, the chromium layer exhibited a very uniform optical distribution.

[0156] In the adhesion tests, the substrates obtained after process (G) (i.e., copper-plated) were subjected to the adhesion tests. The adhesion strength values ​​for ABS and ABS-PC for immersion copper plating and Watt nickel plating are summarized in Table 1 below.

[0157] [Table 1]

[0158] Table 1 shows that ABS and ABS-PC substrates can be etched efficiently and successfully. Further substrates, such as polypropylene (PP), 2K substrates (PC / ABS and PC / ABS-PC), and 3K substrates including rubber, were similarly etched efficiently and successfully (data not shown). In the case of PC / ABS and PC / ABS-PC, only ABS and ABS-PC, respectively, were selectively etched without etching the polycarbonate (PC) component.

[0159] This embodiment demonstrates and confirms that the substrate can be etched in such a way that either nickel metallization (e.g., Watt nickel) or copper metallization (e.g., immersion copper) can be applied in the subsequent metallization process. This allows for great flexibility in further process steps. The adhesion values ​​were very similar; no blistering was observed before and after chromium plating.

[0160] Regarding Table 1, for ABS, an adhesive strength of approximately 0.9 N / mm is generally very acceptable and desirable; Examples 3, 9, and 11 show particularly desirable adhesive strength values. For ABS-PC, an adhesive strength of approximately 0.5 N / mm is generally very acceptable and desirable.

[0161] In several examples, the experimental setup was modified to include a regeneration section (data not shown). In this case, manganese species with an oxidation state of less than +7 were always treated in the regeneration section and re-oxidized to permanganate ions by electric current. These permanganate ions were replenished in the etching composition. This modified setup did not negatively affect the adhesion, but rather allowed for considerably longer use of the etching composition. In this case, silver ions were further utilized.

[0162] Further examples with slightly lower and slightly higher phosphoric acid concentrations also provided acceptable results as long as the concentration did not fall below 7 mol / L or exceed 12 mol / L (data not shown); below these values, or above, etching results suitable for the low permanganate concentration range used in the present invention were not obtained. In particular, the etching composition disclosed in European Patent Application Publication 2025708 (see the example in which the phosphoric acid concentration is considerably above 12 mol / L) exhibits an excessively strong acid concentration, which makes the low permanganate concentrations used in the present invention extremely unstable. Despite the undesirable etching results, this is also highly undesirable, for example, if a regeneration section is utilized. In such cases, an undesirably high amount of energy is consumed for re-oxidation, and re-oxidation is not as efficient as specified in the parameters of the present invention.

[0163] In another set of embodiments where step (C) is also at a temperature of 40°C, step (C) further includes a regeneration section and approximately 1 A / dm 2 The experiment included a step (C-1) that utilized the current at the given current density. The results are summarized in Table 2 below. In contrast, the experiment according to Table 1 was performed based on a feed-and-bleed approach.

[0164] [Table 2]

[0165] Table 2 shows that current-induced regeneration results in more efficient etching than usual.

[0166] For example, Examples 5 and 15 relate to etching of an ABS substrate, and H3PO4 and MnO4 - It provides almost the same concentration. Example 5, following a feed-and-bleed approach, takes 8 minutes to achieve a very acceptable adhesion strength of approximately 1 N / mm. In contrast, Example 15, following electrolytic regeneration, takes only 3 minutes to achieve very similar results. This is a reduction of over 50% in etching time.

[0167] This can also be confirmed for ABS / PC. For example, Example 6 required 20 minutes of etching time to achieve an adhesive strength of approximately 0.5 N / mm, while Example 16 required only 10 minutes to achieve an even greater adhesive strength of more than 0.5 N / mm. Here again, the etching time is significantly reduced.

Claims

1. A method for etching at least one surface of a plastic substrate, (A) Steps to prepare the base material, (B) Depending on the case, a step of bringing the prepared substrate into contact with one or more pretreatment compositions, (C) A step in which the substrate obtained after step (A) or (B) is brought into contact with an etching composition to produce an etched substrate. The etching composition includes, (a) water, (b) Permanganate ions in concentrations of 0.0025 mol / L to 0.1 mol / L (c) Phosphate solution of 7 mol / L to 12 mol / L, (d) 0 to 0.1 mol / L of silver(I) ions, and (e) Manganese(II) ions less than 0 or 10 ppm Includes, At least during step (C), at least a portion of the permanganate ions is converted to manganese species having an oxidation state of less than +7. The aforementioned substrate is a 2-component (2k) substrate containing polycarbonate as one component. A method for selectively etching other components of the substrate without etching the polycarbonate.

2. The method according to claim 1, wherein step (B) does not involve contacting with a pretreatment composition containing an organic solvent.

3. Process (C) (C-1) A step to replenish the etching composition used in step (C) with permanganate ions. The method according to claim 1 or 2, including the method described in claim 1 or 2.

4. - At least a portion of the manganese species having an oxidation state of less than +7 is treated in the regeneration section, and an electric current is applied to reoxidize the manganese species to permanganate ions. - The method according to claim 3, wherein the permanganate ions replenished in step (C-1) are reoxidized in the regeneration section.

5. - By removing at least a portion of the etching composition, at least a portion of the manganese species having an oxidation state of less than +7 is removed from the etching composition. - The method according to claim 3, wherein the permanganate ions replenished in step (C-1) are derived from an alkaline permanganate.

6. The method according to any one of claims 1 to 5, wherein the etching composition has a concentration of permanganate ions in the range of 0.004 mol / L to 0.09 mol / L.

7. The method according to any one of claims 1 to 6, wherein the phosphoric acid in the etching composition has a concentration in the range of 7.4 mol / L to 11.8 mol / L.

8. The method according to any one of claims 1 to 7, wherein the total concentration of all manganese species in the etching composition is in the range of 0.02 mol / L to 0.3 mol / L based on the total volume of the etching composition.

9. The method according to any one of claims 1 to 8, wherein the etching composition substantially does not contain a fluorinated surfactant.

10. The method according to any one of claims 1 to 9, wherein the etching composition has a temperature in the range of 25°C to 60°C during step (C).

11. Furthermore, after process (C), (D) A step of bringing the etched substrate into contact with an activating composition to obtain an activated substrate; and / or (E) A step of bringing an etched or activated substrate into contact with a first metallization composition to deposit a first metal or metal alloy layer on the substrate to produce a first metallized substrate. The method according to any one of claims 1 to 10, including the method described in any one of claims 1 to 10.

12. Furthermore, after step (D) or (E), (F) The activated substrate or the first metallized substrate is brought into contact with the second metallized composition. A step of depositing a second metal or metal alloy layer onto the substrate to produce a second metallized substrate. The method according to any one of claims 1 to 11, including the method described in any one of claims 1 to 11.

13. The method according to claim 12, wherein in step (F), the second metallization composition contains copper ions at a concentration in the range of 0.002 mol / L to 0.4 mol / L based on the total volume of the second metallization composition.

14. The method according to claim 12, wherein the second metallized composition in step (F) contains nickel ions.

15. Furthermore, after step (F), (G) A step of bringing a second metallized substrate into contact with a third metallized composition to deposit a third metal or metal alloy layer onto the substrate by electrolysis to produce a third metallized substrate. The method according to any one of claims 12 to 14, including the method described in any one of claims 12 to 14.

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