Etching solution, pretreatment method, and electroless plating method

Abstract

To provide an etching treatment liquid and a pretreatment method that can etch sufficiently an article to be plated made of a polyamide resin, especially an article to be plated made of nylon 11 and provide the treated resin material with excellent plating deposition and plating film adhesion.SOLUTION: An etching treatment liquid contains a ferric ion of 2.4-5.6 mol / L and has a pH of -1.5 to 2.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an etching solution, a pretreatment method, and an electroless plating method. [Background technology]

[0002] Conventionally, electroless plating has been widely used to form plating films on resin products made from various resins because it has excellent film properties and can form uniform films even on objects with complex shapes. Before forming an electroless plating film on a resin product, a pretreatment such as etching is performed to improve the deposition and adhesion of the plating film, and etching is also performed on polyamide resins (see, for example, Patent Document 1).

[0003] As an etching solution used for plating polyamide resin substrates, for example, when etching a substrate made of nylon 6, hydrochloric acid is used, and when etching a substrate made of nylon 66, chromic acid is used.

[0004] However, when the above-mentioned hydrochloric acid or chromic acid is used as an etching solution, there is a problem in that sufficient plating deposition properties and plating film adhesion are not exhibited on nylon 11.

[0005] The present inventors have noticed that an etching solution containing iron(III) can be used for plating objects made of nylon 11.

[0006] However, it was discovered that when an etching solution containing trivalent iron is used, the trivalent iron is impregnated into the resin, and the oxidizing power of the trivalent iron inhibits the deposition of electroless plating in the subsequent process. Once the trivalent iron is fixed in the resin, it is difficult to remove and reduce.

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a pretreatment method using an etching treatment liquid having a trivalent iron content and a pH within a specific range, and having, after a step of contacting the etching treatment liquid, a step of contacting the surface to be treated with an adhesion inhibitor liquid and a step of contacting the surface with a derusting liquid, and have arrived at the present invention. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-172221 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide an etching solution and a pretreatment method that can satisfactorily etch a substrate made of polyamide resin, particularly nylon 11, and that can impart excellent plating deposition properties and plating film adhesion to the treated resin material. Another object of the present invention is to provide an electroless plating method that can satisfactorily etch a substrate made of polyamide resin, particularly nylon 11, and that can impart excellent plating deposition properties and plating film adhesion. [Means for solving the problem]

[0010] As a result of extensive research into achieving the above object, the present inventors have found that the above object can be achieved by an etching solution containing 2.4 to 5.6 mol / L of iron(III) ions and having a pH of -1.5 to 2.0, as well as a pretreatment method and an electroless plating method that use the etching solution, and have thus completed the present invention.

[0011] That is, the present invention relates to the following etching solution, pretreatment method, and electroless plating method.

[0012] 1. An etching treatment solution containing 2.4 to 5.6 mol / L of iron(III) ions and having a pH of -1.5 to 2.0. 2. The etching solution according to Item 1, wherein the content of the iron (III) ions is 3.0 to 5.0 mol / L. 3. The etching treatment solution according to Item 1 or 2, wherein the iron (III) ions are derived from at least one iron (III) ion source selected from the group consisting of ferric chloride, ferric bromide, ferric iodide, ferric fluoride, ferric sulfide, ferric oxide, ferric tetroxide, ferric citrate, ammonium iron (III) sulfate, and iron (III) oxalate. 4. The etching solution according to any one of items 1 to 3, further comprising a pH buffer. 5. The etching solution according to any one of items 1 to 4, which is for use on a polyamide resin material. 6. A pretreatment method for electroless plating of a resin material, comprising: (1) Step 1: contacting a surface of a resin material to be treated with an etching solution; (2) a step 2 of contacting the treated surface of the resin material with an adhesion suppression liquid; and (3) a step 3 of contacting the treated surface of the resin material with a derusting solution; the etching treatment solution contains 2.4 to 5.6 mol / L of iron (III) ions and has a pH of −1.5 to 2.0; The adhesion inhibitor solution has a liquid temperature of 70°C or higher and a pH of 4 to 8. A pretreatment method characterized by: 7. The pretreatment method according to Item 6, wherein the content of the iron (III) ions in the etching treatment solution is 3.0 to 5.0 mol / L. 8. The pretreatment method according to Item 6 or 7, wherein the iron (III) ions contained in the etching treatment solution are derived from at least one iron (III) ion source selected from the group consisting of ferric chloride, ferric bromide, ferric iodide, ferric fluoride, ferric sulfide, ferric oxide, ferric oxide, ferric citrate, ammonium iron (III) sulfate, and iron (III) oxalate. 9. The pretreatment method according to any one of items 6 to 8, wherein the etching treatment liquid further contains a pH buffering agent. 10. The pretreatment method according to any one of items 6 to 9, wherein the adhesion-inhibiting solution contains a pH buffer. 11. The pretreatment method according to any one of items 6 to 10, wherein the resin material is a polyamide resin material. 12. Step 4 of applying a catalyst to the treated surface of the resin material pretreated by the pretreatment method according to any one of items 6 to 11; and Step 5 includes contacting the surface of the resin material to be treated with an electroless plating solution. Electroless plating method characterized by: [Effects of the Invention]

[0013] When subjected to the pretreatment method of the present invention, the etching solution of the present invention can sufficiently etch a substrate made of polyamide resin, particularly a substrate made of nylon 11, and can impart excellent plating deposition properties and plating film adhesion to the treated resin material. Furthermore, the electroless plating method of the present invention can sufficiently etch a substrate made of polyamide resin, particularly a substrate made of nylon 11, and can exhibit excellent plating deposition properties. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be described in detail below.

[0015] 1. Etching solution The etching solution of the present invention contains 2.4 to 5.6 mol / L of iron (III) ions and has a pH of -1.5 to 2.0. Because the etching solution of the present invention has a specific iron (III) ion content and pH range, when subjected to the pretreatment method of the present invention described below, it can sufficiently etch substrates made of polyamide resins, including not only nylon 6 and nylon 66 but also particularly nylon 11, thereby imparting excellent plating deposition properties to the treated resin material. Therefore, the etching solution of the present invention eliminates the need to change the etching solution depending on the type of polyamide resin, and eliminates the need for process selection. Furthermore, because the etching solution of the present invention has the above-described configuration, chromic acid etching is not required when etching substrates made of nylon 66, thereby reducing environmental impact. Furthermore, the etching solution of the present invention can replenish iron (III) by electrolytic regeneration and electrolysis of an iron plate, thereby reducing costs during continuous use.

[0016] The etching solution of the present invention has a pH of -1.5 to 2.0. If the pH is less than -1.5, sufficient plating deposition properties cannot be obtained for polyamide resins, particularly nylon 11, and the resin material dissolves. If the pH exceeds 2.0, iron hydroxide is produced, which reduces plating deposition properties and adhesion of the plating film. The pH is preferably -1.0 to 1.0, more preferably -0.5 to 0.5. The pH of the etching solution can be adjusted using a pH adjuster described below.

[0017] (iron(III) ions) The iron trivalent ions are not particularly limited as long as they exist as iron trivalent ions in the solvent described below. For example, iron trivalent ions derived from an iron trivalent ion source that dissolves in a solvent to give iron oxide ions can be used. Examples of such iron trivalent ion sources include ferric halides such as ferric chloride, ferric bromide, ferric iodide, and ferric fluoride; and ferric sulfide. As the iron trivalent ion source, ferric halides are preferred, and ferric chloride is more preferred, because they dissolve in solvents such as water and have excellent stability.

[0018] The iron(III) ion sources may be used alone or in combination of two or more.

[0019] In the etching treatment solution of the present invention, the iron (III) ion concentration is 2.4 to 5.6 mol / L. If the iron (III) ion concentration is less than 2.4 mol / L, it is not possible to impart excellent plating deposition properties and plating film adhesion to the treated resin material. If the iron (III) ion concentration exceeds 5.6 mol / L, the treated surface of the resin material will deteriorate. The iron (III) ion content is preferably 2.5 to 5.6 mol / L, more preferably 3.0 to 5.0 mol / L, and even more preferably 4.0 to 4.6 mol / L.

[0020] (pH buffer) The etching solution of the present invention may contain a pH buffer, which suppresses an increase in pH of the etching solution due to etching, thereby suppressing the generation of iron hydroxide and imparting to the treated resin material better plating deposition properties and plating film adhesion.

[0021] The pH buffer is not particularly limited as long as it can stabilize the pH of the etching solution within the above range, and examples thereof include citric acid, acetic acid, boric acid, phosphoric acid, phosphorous acid, carbonic acid, their sodium salts, potassium salts, ammonium salts, etc. Among these, citric acid is preferred in that it further improves plating deposition properties.

[0022] The pH buffering agents may be used alone or in combination of two or more.

[0023] In the etching treatment liquid of the present invention, the content of the pH buffer is preferably 2 to 20 g / L, more preferably 5 to 15 g / L. When the content of the pH buffer is within the above range, the treated resin material can exhibit better plating deposition properties.

[0024] (pH adjuster) The etching solution of the present invention may contain a pH adjuster. By containing a pH adjuster, the pH of the etching solution of the present invention can be adjusted to -1.5 to 2.0, and the treated resin material can be imparted with better plating deposition properties and plating film adhesion.

[0025] The pH adjuster is not particularly limited as long as it can adjust the pH of the etching treatment solution to the above range, and examples thereof include acids such as hydrochloric acid, sulfuric acid, phosphoric acid, etc.; alkalis such as sodium hydroxide, potassium hydroxide, aqueous ammonia, etc. Among these, hydrochloric acid is preferred because it is easier to suppress the increase in pH of the etching treatment solution due to etching, and it is more preferred to use 35% hydrochloric acid.

[0026] In the etching treatment liquid of the present invention, the content of the pH adjuster is not particularly limited as long as it can adjust the pH of the etching treatment liquid to within the above range, and may be adjusted appropriately to obtain the desired pH.

[0027] (Other additives) The etching solution of the present invention may further contain other additives in addition to the above-mentioned iron(III) ions and, if necessary, a pH buffer and a pH adjuster. The other additives are not particularly limited, and may be additives typically used in etching solutions used in pretreatments for forming a plating film, such as surfactants.

[0028] (solvent) The etching treatment solution of the present invention preferably contains the above-mentioned iron(III) ions, and, if necessary, a pH buffer, a pH adjuster, and other additives in a solvent.

[0029] As the solvent, known solvents constituting etching solutions can be used, such as water, alcohol, etc. Water is preferred from the viewpoint of ease of handling and safety.

[0030] The content of the solvent is not particularly limited, and may be the balance after adding the above-mentioned iron (III) ions, and a pH buffer, a pH adjuster, and other additives that are added as needed.

[0031] (Item to be plated) Resin materials that can be plated with the etching solution of the present invention include polyamide resin materials. That is, the etching solution of the present invention is preferably for polyamide resin materials such as nylon 6, nylon 66, and nylon 11. The etching solution of the present invention can be used for resin materials formed from nylon 6 and nylon 66, and can also be used for resin materials formed from nylon 11, which is difficult to plate electrolessly. Therefore, with the etching solution of the present invention, there is no need to change the etching solution depending on the type of polyamide resin, and there is no need to select a process. Furthermore, because the etching solution of the present invention has the above-described configuration, there is no need to perform chromic acid etching when etching a plated object made of nylon 66, thereby reducing the environmental impact.

[0032] 2. Pretreatment method The pretreatment method of the present invention is a pretreatment method for electroless plating of a resin material, comprising: (1) Step 1: contacting a surface of a resin material to be treated with an etching solution; (2) a step 2 of contacting the treated surface of the resin material with an adhesion suppression liquid; and (3) a step 3 of contacting the treated surface of the resin material with a derusting solution; the etching treatment solution contains 2.4 to 5.6 mol / L of trivalent ions and has a pH of −1.5 to 2.0; The anti-adhesion liquid is characterized in that the liquid temperature is 70° C. or higher and the pH is 4 to 8.

[0033] The pretreatment method of the present invention uses the etching solution of the present invention described above and is configured to include the above steps 1 to 3, thereby making it possible to sufficiently etch a substrate made of polyamide resin, particularly a substrate made of nylon 11, and to impart excellent plating deposition properties and plating film adhesion to the treated resin material.

[0034] When an etching solution containing trivalent iron is used as a pretreatment for electroless plating, immersing the resin material to be plated in hot water at 70°C or higher immediately after etching instantaneously forms trivalent iron hydroxide colloids. Iron ions impregnated into the resin material formed from polyamide resin are believed to remain near the surface of the resin material as iron hydroxide without penetrating further in the depth direction. Iron hydroxide remaining near the surface of the resin is easily removed by the subsequent derusting treatment in step 3. Furthermore, the trivalent iron brought in as an etching solution disperses or dissolves in the hot water as hydroxide colloids, suppressing the formation of iron agglomerates.

[0035] The inventors have found that iron hydroxide near the surface of a resin material can be removed by immersing the resin material in hot water and then immersing it in approximately 300 ml / L of hydrochloric acid to dissolve it. However, if the pH of the hot water is below 4, hydroxide colloids do not form, making it difficult to remove iron from near the surface of the resin material. Furthermore, using hot water has the problem that the hot water, lacking pH buffering capacity, becomes acidic after a single pretreatment, making it difficult to use. The inventors have found that by replacing hot water with an adhesion inhibitor containing a pH buffer capable of maintaining a pH of 4 or higher, the effect of converting iron impregnated in the resin material to iron hydroxide can be maintained even after multiple pretreatments, and this can be easily removed during the derusting process, thereby reducing the amount of iron remaining in the resin material. Iron introduced by etching is dispersed as hydroxide colloids or, for example, when ammonium citrate is used as a pH buffer, is dissolved as ammonium iron citrate, thereby suppressing the formation of iron agglomerates. In contrast, the trivalent iron impregnated into the resin material does not dissolve as ferric ammonium citrate, but forms iron hydroxide upon heating. This iron hydroxide is dissolved and removed by contact with a derusting solution in step 3, thereby suppressing iron aggregation in the resin material. Furthermore, after the pretreatment method of the present invention, in step 4 of the electroless plating method of the present invention described below, the catalyst can be applied by any of the sensitizer-activator method, catalyst-accelerator method, and alkali ion catalyst method.

[0036] The pretreatment method of the present invention may include a heat treatment (annealing) step before the above steps 1 to 3. That is, the pretreatment method of the present invention may include a heat treatment step, step 1, step 2, and step 3 in this order. Each step of the above pretreatment method will now be described.

[0037] (Heat treatment process) The pretreatment method of the present invention preferably includes a heat treatment (annealing) step before step 1. By including a heat treatment step before step 1, the resin material can be more thoroughly etched in step 1, which will be described later, and the treated resin material can be endowed with better plating deposition properties and plating film adhesion.

[0038] The heat treatment method in the heat treatment step is not particularly limited as long as it is a heat treatment method typically used in pretreatment methods for plating films, and examples thereof include methods in which the plated film is placed in a thermostatic bath, a heating furnace, an electric furnace, etc. The atmosphere for the heat treatment is not particularly limited, and examples thereof include air, vacuum, and inert gas atmospheres. Examples of inert gases include argon, helium, nitrogen, and ammonia.

[0039] The heat treatment temperature in the heat treatment step is not particularly limited as long as it is a temperature typically used in pretreatment methods for plating films, and is preferably 100 to 140° C., more preferably 110 to 130° C. If the heat treatment temperature is within the above range, the resin material is more thoroughly dried, and excessive etching of the resin material is further suppressed in step 1, which will be described later.

[0040] The heat treatment time in the heat treatment step is not particularly limited, as long as it is within the range of heating typically used in pretreatment methods for plating films. The heat treatment time is preferably 30 minutes or more, more preferably 45 minutes or more. The heat treatment time is preferably 2 hours or less, more preferably 1 hour 30 minutes or less. By setting the lower limit of the heat treatment time within the above range, the resin material is more thoroughly dried, and excessive etching of the resin material is further suppressed in step 1, which will be described later. Furthermore, by setting the upper limit of the heat treatment time within the above range, embrittlement of the resin material is further suppressed.

[0041] (Process 1) Step 1 is a step of bringing the surface of a resin material to be treated into contact with an etching treatment liquid. The etching treatment liquid used in Step 1 contains 2.4 to 5.6 mol / L of ferric ions and has a pH of -1.5 to 2.0. The etching treatment liquid used in Step 1 may be the etching treatment liquid of the present invention described above. Furthermore, the resin material may be any of the resin materials described above as the object to be plated, and a polyamide resin material is preferred.

[0042] The method for contacting the treated surface of the resin material with the etching treatment solution may be any method commonly used for pretreatment of electroless plating, such as immersing the resin material in the etching treatment solution.

[0043] The temperature of the etching solution in step 1 is not particularly limited as long as it can adequately etch the surface of the resin material. For example, if the resin material is in a block form, the temperature is preferably 50 to 100°C, more preferably 70 to 90°C. If the resin material is in a film form, the temperature is preferably 30 to 50°C, more preferably 35 to 45°C. By keeping the upper limit of the temperature within the above range, dissolution of the resin material is suppressed. Furthermore, by keeping the lower limit of the temperature within the above range, the resin material is sufficiently etched.

[0044] The treatment time in step 2 is not particularly limited as long as it can adequately etch the substrate surface, and is preferably 3 to 30 minutes, more preferably 5 to 20 minutes, and even more preferably 8 to 15 minutes. By keeping the upper limit of the treatment time within the above range, dissolution of the resin material is suppressed and excessive roughening of the resin material surface is suppressed. Furthermore, by keeping the lower limit of the treatment time within the above range, etching of the resin material is sufficient.

[0045] (Process 2) Step 2 is a step of bringing the surface of the resin material to be treated into contact with an adhesion-inhibiting solution. By including Step 2 in the pretreatment method of the present invention, adhesion of iron impregnated into the resin material to be plated to the resin material is inhibited, and coagulation of iron in the resin material is inhibited.

[0046] The adhesion-inhibiting liquid used in step 2 is not particularly limited as long as it can form a hydroxide colloid of iron(III) on the surface of the resin material that has been subjected to step 1 and can disperse or dissolve the hydroxide colloid in the adhesion-inhibiting liquid. Examples of such adhesion-inhibiting liquids include adhesion-inhibiting liquids containing a pH buffer.

[0047] The pH buffer contained in the adhesion-inhibiting liquid is not particularly limited as long as it has pH buffering ability, and examples thereof include citric acid, acetic acid, boric acid, phosphoric acid, phosphorous acid, carbonate, and their sodium salts, potassium salts, ammonium salts, etc. Among these, citric acid and citrate salts are preferred, citrate salts are more preferred, and triammonium citrate is even more preferred, in that they make it easier to control the pH of the adhesion-inhibiting liquid to 4 to 8, more easily form trivalent iron hydroxide colloid on the surface of the resin material, and enable the trivalent iron to be further dispersed or dissolved in the adhesion-inhibiting liquid.

[0048] The pH buffering agents may be used alone or in combination of two or more.

[0049] In the adhesion-inhibiting solution used in step 2, the content of the pH buffer is preferably 10 g / L or more, more preferably 50 g / L or more. The content of the pH buffer is preferably 100 g / L or less, more preferably 70 g / L or less. When the lower limit of the pH buffer content is within the above range, it becomes easier to control the pH of the adhesion-inhibiting solution to 4 to 8, which makes it easier to form trivalent iron hydroxide colloid near the surface layer of the resin material, and enables the trivalent iron carried over from the etching treatment solution to be further dispersed or dissolved. When the upper limit of the pH buffer content is within the above range, the adhesion prevention effect is further improved.

[0050] The pH of the adhesion inhibitor solution is 4 to 8. If the pH is less than 4, a hydroxide colloid of iron(III) is not formed near the surface of the resin material, and iron on the surface of the resin material cannot be removed. If the pH is more than 8, the iron(III) carried over from the etching solution cannot be further dispersed or dissolved. The pH is preferably 4 to 8, and more preferably 6 to 7.

[0051] The method for contacting the treated surface of the resin material with the adhesion suppression solution may be any method commonly used for pretreatment of electroless plating, such as immersing the resin material in the adhesion suppression solution.

[0052] The temperature of the adhesion suppression solution in step 2 is 70°C or higher. If the temperature is lower than 70°C, iron(III) hydroxide colloid will not be formed near the surface of the resin material, and iron near the surface of the resin material will not be removed. The temperature is preferably 75°C or higher, more preferably 80°C or higher. The temperature is preferably 90°C or lower, more preferably 85°C or lower.

[0053] The treatment time in step 2 is not particularly limited as long as it forms a hydroxide colloid of iron(III) near the surface of the resin material and removes the iron near the surface of the resin material, but is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more. The upper limit of the treatment time is not particularly limited, and may be approximately 20 minutes or less.

[0054] (Step 3) Step 3 is a step of contacting the treated surface of the resin material with a derusting solution. By including Step 3 in the pretreatment method of the present invention, iron(III) hydroxide colloids are dissolved and removed from the surface of the resin material, and iron aggregation on the resin material is suppressed. This makes it possible to suppress the adsorption inhibition and deactivation of the catalyst on the surface of the resin material in the subsequent step.

[0055] The derusting liquid used in step 3 is not particularly limited as long as it can dissolve and remove iron(III) hydroxide colloid on the surface of the resin material that has been subjected to step 2, and can suppress iron aggregation in the resin material. Examples of such derusting liquids include derusting liquids containing a derusting agent.

[0056] Examples of the rust removing agent include acids such as hydrochloric acid and sulfuric acid, iron reducing agents such as ascorbic acid and stannous chloride, etc. Among these, acids are preferred because of their superior rust removing effect, and hydrochloric acid is more preferred.

[0057] A specific example of a derusting solution containing a derusting agent is 35% hydrochloric acid.

[0058] The above rust removers may be used alone or in combination of two or more.

[0059] In the derusting solution used in step 3, the content of the derusting agent is preferably 250 ml / L or more, more preferably 300 ml / L or more. When the lower limit of the content of the derusting agent is within the above range, the dissolution and removal of the trivalent iron hydroxide colloid near the surface layer of the resin material is more sufficient, and the aggregation of iron in the resin material is more suppressed. Furthermore, the upper limit of the content of the derusting agent is not particularly limited, and it is sufficient as long as it is about 400 ml / L or less.

[0060] The method for contacting the treated surface of the resin material with the derusting solution may be any conventional method used for pretreatment of electroless plating, such as immersing the resin material in the derusting solution.

[0061] The temperature of the derusting solution in step 3 is not particularly limited as long as it can dissolve and remove iron(III) hydroxide colloids on the surface of the resin material and suppress iron aggregation in the resin material. The temperature of the derusting solution is preferably 30°C or higher, more preferably 40°C or higher. The temperature of the derusting solution is preferably 50°C or lower, more preferably 45°C or lower.

[0062] The treatment time in step 3 is not particularly limited as long as it can dissolve and remove the iron(III) hydroxide colloid on the surface of the resin material and suppress iron aggregation in the resin material, and is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more. There is also no particular upper limit to the treatment time, and it may be approximately 10 minutes or less.

[0063] 3. Electroless plating method The electroless plating method of the present invention includes a step 4 of applying a catalyst to the surface of the resin material pretreated by the pretreatment method of the present invention described above; The method is characterized by including step 5 of bringing the surface of the resin material to be treated into contact with an electroless plating solution. Each step of the electroless plating method will now be described.

[0064] (Step 4) Step 4 is a step of applying a catalyst to the treated surface of the resin material pretreated by the pretreatment method of the present invention. By including Step 4 in the electroless plating method of the present invention, it becomes easier to form an electroless plating film on the treated surface of the resin material.

[0065] The method for applying a catalyst to the surface of the resin material to be treated may be any of the usual catalyst application methods used in electroless plating, such as a method in which a catalyst application liquid is brought into contact with the surface of the resin material to be treated.

[0066] Examples of the catalyst application liquid include solutions containing ions of metals such as gold, palladium, silver, ruthenium, and platinum.

[0067] The content of metal ions in the catalyst application liquid may be the same as the content of metal ions in a catalyst application liquid normally used in electroless plating, and may be, for example, about 0.01 to 1 g / L.

[0068] The temperature of the catalyst imparting liquid in step 4 is not particularly limited as long as it can impart the catalyst to the surface of the resin material to be treated, and may be about 10 to 60°C.

[0069] The treatment time with the catalyst imparting liquid in step 4 is not particularly limited as long as it is possible to impart the catalyst to the surface of the resin material to be treated, and may be about 1 to 10 minutes.

[0070] (Activation process) In the electroless plating method of the present invention, an activation treatment using an activation treatment solution containing a reducing agent and / or an organic acid may be carried out between steps 4 and 5 in order to improve the deposition properties of the electroless plating.

[0071] The reducing agent used in the activation treatment is not particularly limited, and examples thereof include dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, hydrazine, hypophosphite, erythorbic acid, ascorbic acid, hydroxylamine sulfate, hydrogen peroxide, glucose, etc. Among these, dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, and hydrazine are preferred in terms of achieving better plating deposition properties.

[0072] The reducing agents may be used alone or in combination of two or more.

[0073] The concentration of the reducing agent in the activation treatment solution is not particularly limited, but is preferably 0.1 to 500 g / L, more preferably about 1 to 50 g / L, and even more preferably 2 to 25 g / L.

[0074] The organic acid used in the activation treatment is not particularly limited, and examples thereof include formic acid, oxalic acid, glycolic acid, tartaric acid, citric acid, maleic acid, acetic acid, propionic acid, malonic acid, succinic acid, lactic acid, malic acid, gluconic acid, glycine, alanine, aspartic acid, glutamic acid, iminodiacetic acid, nitrilotriacetic acid, fumaric acid, etc. Among these, formic acid, oxalic acid, glycolic acid, tartaric acid, citric acid, and maleic acid are preferred in terms of better plating deposition properties.

[0075] The organic acids may be used alone or in combination of two or more.

[0076] The concentration of the organic acid in the activation treatment solution is not particularly limited, but is preferably 0.1 to 500 g / L, more preferably about 1 to 50 g / L, and even more preferably 2 to 25 g / L.

[0077] The activation treatment method is not particularly limited, and for example, the resin material pretreated in step 4 above may be immersed in an activation treatment liquid at a liquid temperature of about 15 to 50° C. for a few seconds to about 10 minutes.

[0078] (Step 5) Step 5 is a step of bringing the surface of the resin material to be treated into contact with an electroless plating solution.

[0079] The method for contacting the treated surface of the resin material with the electroless plating solution is not particularly limited, and may be any conventionally known method. As the method, a method of immersing the treated surface of the resin material in the electroless plating solution is preferred in terms of superior contact efficiency.

[0080] The electroless plating solution is not particularly limited, and any conventionally known autocatalytic electroless plating solution can be used, including electroless nickel plating solution, electroless copper plating solution, electroless silver plating solution, electroless cobalt plating solution, electroless nickel-cobalt alloy plating solution, and electroless gold plating solution.

[0081] The electroless plating solution preferably contains a reducing agent that exhibits catalytic activity toward metal ions, such as dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, hydrazine, or formic acid.

[0082] The conditions for contacting the treated surface of the resin material with the electroless plating solution are not particularly limited. For example, when the resin material is immersed in the electroless plating solution, the temperature of the electroless plating solution may be set to about 20 to 70°C, and the immersion time may be set to about 3 to 30 minutes.

[0083] The content of the reducing agent in the electroless plating solution is not particularly limited, but is preferably about 0.01 to 100 g / L, and more preferably about 0.1 to 10 g / L. By setting the lower limit of the reducing agent content within the above range, the deposition properties of the plating are further improved, and by setting the upper limit of the reducing agent content within the above range, the stability of the electroless plating bath is further improved.

[0084] In the electroless plating method of the present invention, step 5 may be repeated two or more times as necessary. By repeating step 5 two or more times, two or more layers of electroless plating film are formed.

[0085] (Electroplating process) In the method for electroless plating of a resin material of the present invention, step 5 may be followed by an additional electroplating step.

[0086] In the electroplating step, after the above step 5, activation treatment is carried out with an aqueous solution of acid, alkali, or the like, if necessary, and the resin material is then immersed in an electroplating solution to carry out electroplating.

[0087] The electroplating solution is not particularly limited, and may be appropriately selected from conventionally known electroplating solutions depending on the purpose.

[0088] The electroplating method is not particularly limited, and for example, the resin material on which the electroless plating film has been formed in step 5 above is immersed in an electroplating solution having a liquid temperature of about 15 to 50°C, and the resin material is immersed in the electroplating solution at a current density of 0.1 to 10 A / dm 2 It is sufficient to immerse the material in the above conditions for a few seconds to an hour. [Example]

[0089] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0090] (Item to be plated) As the resin material to be plated, a film (10 cm x 5 cm x 25 μm) of a resin material made from nylon 11 (Polyamide 11 resin manufactured by Arkema, product name: Rilsan BMN O) was prepared.

[0091] Example 1 The above-mentioned plated object was subjected to annealing, water washing, and surface preparation under the conditions shown in Table 1 below, followed by etching, adhesion prevention treatment, water washing, rust removal, and water washing.

[0092] [Table 1]

[0093] Next, the above-mentioned object to be plated was immersed in a catalyst imparting solution having the following composition at a temperature of 40° C. for an immersion time of 5 minutes to impart the catalyst to the surface of the object to be plated.

[0094] Next, the substrate to be plated to which the catalyst was applied was immersed in an electroless plating solution of the following composition at a temperature of 40°C for an immersion time of 15 minutes, and brought into contact with the electroless plating solution to form the electroless plating film of Example 1.

[0095] (Comparative Example 1) The object to be plated was brought into contact with the electroless plating solution in the same manner as in Example 1, except that the etching treatment was not carried out.

[0096] (Comparative Example 2) The object to be plated was brought into contact with the electroless plating solution in the same manner as in Example 1, except that the adhesion prevention treatment and the rust removal treatment were not carried out.

[0097] (Comparative Example 3) The object to be plated was brought into contact with the electroless plating solution in the same manner as in Example 1, except that the adhesion prevention treatment was not carried out. Comparative Example 4 The object to be plated was brought into contact with the electroless plating solution in the same manner as in Example 1, except that the rust removal treatment was not carried out.

[0098] [evaluation] In the examples and comparative examples, the surfaces of the objects to be plated were visually observed and evaluated after they were brought into contact with the electroless plating solution. The results are shown in Table 2.

[0099] [Table 2]

[0100] The results in Table 2 show that in Example 1, in which the etching solution of the present invention was used and pretreatment was performed by the pretreatment method of the present invention, which includes etching, adhesion inhibition treatment, and derusting treatment, sufficient electroless plating was deposited even on the plated object made of nylon 11, which is difficult to plate electrolessly, and that the plated object had excellent plating deposition properties.

[0101] In contrast, in Comparative Example 1, in which no etching treatment was performed, the electroless plating film formed on the surface of the plated object peeled off, indicating that the adhesion of the plating film to the plated object made of nylon 11 was poor.

[0102] Furthermore, in Comparative Examples 2 to 4, in which no adhesion inhibiting treatment and / or rust removal treatment was performed, electroless plating did not deposit on the plated object formed of nylon 11, and it was found that plating deposition was poor.

Claims

1. A pretreatment method for electroless plating of a resin material, comprising: (1) Step 1: contacting the surface of a resin material to be treated with an etching treatment solution; (2) a step 2 of contacting the treated surface of the resin material with an adhesion suppression liquid; and (3) a step 3 of contacting the treated surface of the resin material with a derusting liquid; the etching treatment solution contains 2.4 to 5.6 mol / L of iron (III) ions and has a pH of −1.5 to 2.0; The adhesion inhibitor solution has a liquid temperature of 70°C or higher and a pH of 4 to 8, The resin material is a polyamide resin material. A pretreatment method characterized by:

2. 2. The pretreatment method according to claim 1, wherein the content of the iron (III) ions in the etching treatment solution is 3.0 to 5.0 mol / L.

3. 3. The pretreatment method according to claim 1, wherein the iron (III) ions contained in the etching treatment solution are derived from at least one iron (III) ion source selected from the group consisting of ferric chloride, ferric bromide, ferric iodide, ferric fluoride, ferric sulfide, ferric oxide, ferric oxide, ferric citrate, ammonium iron (III) sulfate, and iron (III) oxalate.

4. 4. The pretreatment method according to claim 1, wherein the etching solution further contains a pH buffer.

5. The pretreatment method according to any one of claims 1 to 4, wherein the adhesion suppression solution contains a pH buffer.

6. Step 4 of applying a catalyst to the treated surface of the resin material pretreated by the pretreatment method according to any one of claims 1 to 5; and Step 5 includes contacting the surface of the resin material to be treated with an electroless plating solution. Electroless plating method characterized by:

Images