Palladium-containing graft polymers, methods of making and using the same

Abstract

The present application relates to a kind of palladium-containing graft polymer and its preparation method and application.The palladium-containing graft polymer includes water-soluble polymer trunk and palladium-containing polyoxometalate grafted on the water-soluble polymer trunk, with the advantages of not easy to hydrolyze and agglomerate, high stability, long life, etc., which can be used to prepare palladium activation liquid with high stability and long life, and then used in electroless plating.

Description

Technical Field

[0001] This invention relates to the field of palladium activating solution technology, and in particular to a palladium-grafted polymer, its preparation method, and its application. Background Technology

[0002] Non-metallic materials are mostly non-conductors, and a conductive film must be prepared before electroplating their surfaces. Currently, the most common method is electroless plating. Before electroless plating, the substrate must undergo pretreatment, generally including degreasing, pre-immersion, activation, and reduction. The purpose of activation is to adsorb a certain number of activation centers on the non-metallic substrate to induce subsequent electroless plating. Activation not only determines the quality of the electroless plating layer but also its overall quality. Palladium activating solution is a commonly used activator, capable of forming a layer of highly catalytically active palladium species on the substrate surface.

[0003] However, traditional palladium activation solutions suffer from low stability and short lifespan, especially those with low palladium content. Current palladium activation solutions typically use inorganic palladium salts as the palladium source, such as palladium sulfate or palladium chloride, and add complexing agents and surfactants to improve stability and extend lifespan. However, because palladium ion complexes are thermodynamically unstable, hydrolysis and precipitation still occur. Therefore, the industry urgently needs to develop a solution that can effectively inhibit palladium ion hydrolysis, thereby extending the lifespan of palladium activation solutions. Summary of the Invention

[0004] Based on this, the present invention provides a palladium-grafted polymer that is not easily hydrolyzed or agglomerated, has high stability and long lifespan, which can be used to prepare palladium activation solutions with high stability and long lifespan, and then used in electroless plating.

[0005] The technical solution is as follows:

[0006] A palladium-grafted polymer includes a water-soluble polymer backbone and a palladium-containing polyoxometalate grafted onto the water-soluble polymer backbone.

[0007] In one embodiment, the palladium-containing polyoxometalate is selected from [Pd]. II 13 O8(LXO3)8] n- [Cu] II 2Pd II 22 P 12 O 60 (OH)8] 20- 、[Pd 15 O 10 -(PO4) 10 ] 20- , and [Pd] II 7VV 6O 24 (OH)2] 6- At least one of the following:

[0008] Where X represents As V L represents O or a benzene ring, and n is taken from 5 to 10; or

[0009] X represents Se IV L represents a lone pair, and n is taken from 5 to 10.

[0010] In one embodiment, the grafting rate of the palladium-containing polyoxometalate in the palladium-containing grafted polymer is 10% to 80%.

[0011] In one embodiment, the weight-average molecular weight of the palladium-grafted polymer is 500 g / mol to 50000 g / mol.

[0012] In one embodiment, the water-soluble polymer backbone is selected from at least one of polyethylene glycol monomethyl ether, polymaleic anhydride, polyvinyl alcohol, and polyacrylamide.

[0013] In one embodiment, the water-soluble polymer and the palladium-containing polyoxometalate are linked by at least one of amino, thiol, and oxygen groups.

[0014] The present invention also provides a method for preparing the palladium-grafted polymer as described above, comprising the following steps:

[0015] Preparation of palladium-containing polyoxometalates;

[0016] The palladium-containing polyoxometalate was organically modified to prepare a modified palladium-containing polyoxometalate.

[0017] The modified palladium-containing polyoxometalate was mixed with a water-soluble polymer and an initiator, and the palladium-containing graft polymer was prepared by graft copolymerization.

[0018] In one embodiment, the preparation of palladium-containing polyoxometalates includes the following steps:

[0019] Using metal salts and / or metal alkoxides as metal precursors, a sol is formed through hydrolysis, dehydration, de-alcoholization, and condensation. The sol is then converted into palladium-containing polyoxometalates by heating or solvent evaporation.

[0020] The metal precursor includes a palladium salt.

[0021] In one embodiment, the palladium salt is selected from at least one of PdCl2, Pd(CH3COO)2 and Pd3(CH3COO)6.

[0022] In one embodiment, the modifier used in the organic modification step is a silane coupling agent.

[0023] In one embodiment, the modifier used in the organic modification step is an aminosilane coupling agent, a mercaptosilane coupling agent, or an alkoxysilane coupling agent.

[0024] In one embodiment, the molar ratio of the modifier used in the organic modification step to the palladium-containing polyoxometalate is (1-4):1.

[0025] In one embodiment, the parameters for organic modification include:

[0026] The temperature ranges from 20℃ to 100℃, and the time ranges from 2 hours to 16 hours.

[0027] In one embodiment, the molar ratio of the water-soluble polymer to the modified palladium-containing polyoxometalate is (0.5–2):1.

[0028] In one embodiment, the water-soluble polymer is selected from at least one of polyethylene glycol monomethyl ether, polymaleic anhydride, polyvinyl alcohol, and polyacrylamide.

[0029] In one embodiment, the total molar ratio of the water-soluble polymer and the modified palladium-containing polyoxometalate to the initiator is 1:(0.001 to 0.1).

[0030] In one embodiment, the initiator is selected from at least one of azobisisobutyronitrile and benzoin ether.

[0031] In one embodiment, the parameters of the graft copolymerization reaction include:

[0032] The temperature ranges from 0℃ to 40℃, and the time ranges from 4h to 50h.

[0033] The present invention also provides a palladium activating solution, which includes a solvent and a palladium-containing grafted polymer as described above, or a palladium-containing grafted polymer prepared according to the preparation method described above.

[0034] In one embodiment, the concentration of the palladium-grafted polymer in the palladium activating solution is 0.01 mM to 0.05 mM.

[0035] In one embodiment, the solvent is water.

[0036] In one embodiment, the pH of the palladium activation solution is 5 to 7.

[0037] In one embodiment, the palladium activating solution further includes a pH adjuster.

[0038] In one embodiment, the pH adjuster is selected from at least one of boric acid, hydrochloric acid, phosphoric acid, sulfuric acid, ammonium chloride, ammonia, acetic acid, sodium hydroxide, and potassium hydroxide.

[0039] The present invention also provides the application of the palladium activating solution as described above in electroless plating.

[0040] In one embodiment, the application is the step of using the palladium activating solution to activate a non-metallic material surface.

[0041] The present invention has the following beneficial effects:

[0042] The palladium-grafted polymer provided by this invention comprises a water-soluble polymer and a palladium-containing polyoxometalate grafted onto the water-soluble polymer. It is a hybrid compound, soluble in water, and uniformly dispersed in aqueous solution. It possesses advantages such as high stability, resistance to aggregation, and minimal hydrolysis of palladium ions. Using it in palladium activation solutions can effectively improve the stability of the activation solution and extend its service life, showing broad application prospects in electroless plating.

[0043] In addition, the palladium-grafted polymer of the present invention has the advantages of simple operation, low equipment investment, green and environmentally friendly, controllable quality and easy industrialization, which can generate good economic and social benefits and has broad application prospects. Attached Figure Description

[0044] Figure 1 Images showing the metallization effect on the surface of FR-4 resin, including... Figure 1 Image 'a' shows the incoming resin material. Figure 1 Image b shows the effect of chemical nickel plating on the resin surface. Figure 1 c is an image showing the effect of chemical copper plating on the resin surface;

[0045] Figure 2 Images showing the surface metallization effect of EMC packaging materials, among which... Figure 2 Image 'a' is an EMC incoming material image. Figure 2 Image b shows the effect of electroless nickel plating on the EMC surface. Figure 2 c is an image showing the effect of chemical copper plating on an EMC surface;

[0046] Figure 3 The results show the appearance changes after using different palladium activation solutions for 3 months. Figure 3 a shows the appearance changes of the palladium activation solution in Example 1 after 3 months of use. Figure 3 b shows the appearance changes of the palladium activation solution in Comparative Example 1 after 3 months of use. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0049] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0050] In this invention, the terms "preferredly," "more preferably," "better," and "even better" refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of the invention. That is, in this invention, "preferredly," "more preferably," "better," and "even better" are merely descriptions of more effective implementations or examples, but do not constitute a limitation on the scope of protection of the invention.

[0051] In this invention, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0052] In this invention, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this invention, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0053] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0054] Unless otherwise specified, all steps of this invention may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0055] In this invention, "above" or "below" both include the number itself. For example, "below 1" includes 1.

[0056] Unless otherwise specified, the temperature parameters in this invention can be either constant temperature treatment or variations within a certain temperature range. It should be understood that the constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃.

[0057] In this invention, M represents mol / L.

[0058] Unless otherwise stated, a singular term may include a plural term and should not be understood as having a quantity of one.

[0059] In this invention, the polymer types / names conform to relevant definitions in the chemical industry, and polymer A is a general term for polymers and their derivatives. For example, polyacrylamide (PAM) is a general term for polymers obtained by homopolymerization of acrylamide or copolymerization with other monomers. It is one of the most widely used water-soluble polymers. Polyacrylamide contains amide groups in its structural units, which easily form hydrogen bonds, giving it good water solubility and high chemical activity. It is easy to obtain various modified products with branched or network structures through grafting or crosslinking.

[0060] Unless otherwise specified, all raw materials, reagents, and other materials used in the following specific implementation methods are commercially available products.

[0061] Traditional palladium activation solutions suffer from low stability and short lifespan, especially those with low palladium content.

[0062] Currently, a scheme has been reported to improve the stability of palladium ion activation solution by using a polyethyleneimine-benzyl hexacarboxylic acid complex (1-5 mg / L); or a scheme to improve the stability and service life of divalent palladium complex solution by using tartaric acid (0.5 mmol / L) as the first complexing agent and 3-pyridinemethylamine (0.5 mmol / L) as the second complexing agent; or a scheme to improve the stability of ion palladium activation solution by using a polyamide-amine resin-glycine complex and cinnamaldehyde; or a scheme to improve the stability of ion palladium solution by using a single substance or combination of malic acid, citric acid, lactic acid, propionic acid, glycolic acid, triethanolamine, glycine, thiourea, and potassium iodide; or a scheme to improve the stability of ion palladium activator by using a metal masking agent to reduce the impact of water quality and foreign impurities on activation performance; and a scheme to extend the service life of palladium activation solution by using sodium ethylenediaminetetraacetate as a complexing agent and sodium isooctyl sulfate as a surfactant.

[0063] While the above-mentioned methods can improve the stability of palladium activation solutions to some extent, the improvement is limited, and they also have problems such as complex preparation steps, high costs, or time consumption.

[0064] To address the issues of poor stability and short lifespan of traditional palladium activation solutions, this invention provides a palladium-grafted polymer that is less prone to hydrolysis and aggregation, exhibits high stability, and has a long lifespan. By using a palladium-containing polyoxometalate as the palladium source and a water-soluble polymer as the carrier and dispersant, the hydrolysis and aggregation of palladium species in the activation solution can be effectively suppressed, thereby improving the stability of the palladium activation solution.

[0065] The technical solution is as follows:

[0066] A palladium-grafted polymer includes a water-soluble polymer backbone and a palladium-containing polyoxometalate grafted onto the water-soluble polymer backbone.

[0067] In one embodiment, the palladium-containing polyoxometalate is selected from [Pd]. II 13 O8(LXO3)8] n- [Cu] II 2Pd II 22 P 12 O 60 (OH)8] 20- 、[Pd 15 O 10 -(PO4) 10 ] 20- , and [Pd] II 7V V 6O 24 (OH)2] 6- At least one of the following:

[0068] Where X represents As V L represents O or a benzene ring, and n is taken from 5 to 10, including but not limited to 5, 6, 7, 8, 9, or 10; or

[0069] X represents Se IV L represents a lone pair, and n is taken from 5 to 10, including but not limited to 5, 6, 7, 8, 9 or 10.

[0070] In one embodiment, the grafting rate of the palladium-containing polyoxometalate in the palladium-grafted polymer is 10% to 80%, which is more conducive to improving the stability of the palladium-grafted polymer, and thus improving the stability of the palladium activation solution. It is understood that the grafting rate of the palladium-containing polyoxometalate in the palladium-grafted polymer includes, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%.

[0071] In one embodiment, the weight-average molecular weight of the palladium-grafted polymer is 500 g / mol to 50000 g / mol, which is more conducive to improving the stability of the palladium-grafted polymer and thus improving the stability of the palladium activation solution. It is understood that the weight-average molecular weight of the palladium-grafted polymer includes, but is not limited to, 500 g / mol, 600 g / mol, 700 g / mol, 800 g / mol, 1000 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, and 5500 g / mol. The weight-average molecular weights of the palladium-grafted polymers are 1, 6000 g / mol, 6500 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, 12000 g / mol, 15000 g / mol, 20000 g / mol, 22000 g / mol, 25000 g / mol, 30000 g / mol, 32000 g / mol, 35000 g / mol, 40000 g / mol, or 50000 g / mol. Further, the weight-average molecular weight of the palladium-grafted polymer is 600 g / mol to 40000 g / mol.

[0072] In one embodiment, the water-soluble polymer backbone is selected from at least one of polyethylene glycol monomethyl ether, polymaleic anhydride, polyvinyl alcohol, and polyacrylamide, which is more conducive to improving the stability of the palladium-grafted polymer, thereby improving the stability of the palladium-activated solution. Understandably, the water-soluble polymer backbone is polyethylene glycol monomethyl ether, or polymaleic anhydride, or polyvinyl alcohol, or polyacrylamide, or a mixture of polyethylene glycol monomethyl ether and polymaleic anhydride, or a mixture of polyethylene glycol monomethyl ether and polyvinyl alcohol, or a mixture of polyethylene glycol monomethyl ether and polyacrylamide.

[0073] In one embodiment, the water-soluble polymer and the palladium-containing polyoxometalate are linked by at least one of amino, thiol, and oxygen groups.

[0074] The present invention also provides a method for preparing the palladium-grafted polymer as described above, comprising the following steps:

[0075] Preparation of palladium-containing polyoxometalates;

[0076] The palladium-containing polyoxometalate was organically modified to prepare a modified palladium-containing polyoxometalate.

[0077] The modified palladium-containing polyoxometalate was mixed with a water-soluble polymer and an initiator, and the palladium-containing graft polymer was prepared by graft copolymerization.

[0078] In one embodiment, the preparation of palladium-containing polyoxometalates includes the following steps:

[0079] Using metal salts and / or metal alkoxides as metal precursors, a sol is formed through hydrolysis, dehydration, de-alcoholization, and condensation. The sol is then converted into palladium-containing polyoxometalates by heating or solvent evaporation.

[0080] The metal precursor includes a palladium salt.

[0081] Understandably, the metal precursor is a metal salt, a metal alkoxide, or a mixture of a metal salt and a metal alkoxide.

[0082] In one embodiment, the metal precursor is a metal salt, including a palladium salt. Further, the palladium salt is selected from at least one of PdCl2, Pd(CH3COO)2, and Pd3(CH3COO)6.

[0083] In one embodiment, the modifier used in the organic modification step is a silane coupling agent.

[0084] In one embodiment, the modifier used in the organic modification step is an aminosilane coupling agent, a mercaptosilane coupling agent, or an alkoxysilane coupling agent. Preferably, the modifier is an aminosilane coupling agent.

[0085] In one embodiment, the molar ratio of the modifier used in the organic modification step to the palladium-containing polyoxometalate is (1-4):1, including but not limited to 1:1, 2:1, 3:1 or 4:1.

[0086] In one embodiment, the parameters for organic modification include:

[0087] The temperature ranges from 20℃ to 100℃, and the time ranges from 2 hours to 16 hours.

[0088] In one embodiment, the palladium-containing polyoxometalate is organically modified to prepare the modified palladium-containing polyoxometalate, which includes the following steps:

[0089] Dissolve 1 mmol of palladium-containing polyoxometalate in 100 ml of acetonitrile or ethanol, add 1 mmol to 4 mmol of silane, reflux for 12 h to 16 h, cool to room temperature, and then dry under vacuum.

[0090] In one embodiment, the water-soluble polymer is selected from at least one of polyethylene glycol monomethyl ether, polymaleic anhydride, polyvinyl alcohol, and polyacrylamide. Further, the water-soluble polymer contains unsaturated bonds. Further still, the unsaturated bonds are alkenyl groups. Even further still, the alkenyl group is an allyl group.

[0091] Optionally, the water-soluble polymer may be allyl polyethylene glycol monomethyl ether, or allyl polymaleic anhydride, or allyl polyvinyl alcohol, or allyl polyacrylamide, or a mixture of allyl polyethylene glycol monomethyl ether and allyl polymaleic anhydride, or a mixture of allyl polyethylene glycol monomethyl ether and allyl polyvinyl alcohol, or a mixture of allyl polyethylene glycol monomethyl ether and allyl polyacrylamide.

[0092] In one embodiment, the weight-average molecular weight of the water-soluble polymer is 400 g / mol to 40000 g / mol, which is more conducive to improving the stability of the palladium-grafted polymer, thereby improving the stability of the palladium activation solution. It is understood that the weight-average molecular weight of the water-soluble polymer includes, but is not limited to, 400 g / mol, 500 g / mol, 600 g / mol, 700 g / mol, 800 g / mol, 1000 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, and 5000 g / mol. The weight-average molecular weights of the water-soluble polymers are 5500 g / mol, 6000 g / mol, 6500 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, 12000 g / mol, 15000 g / mol, 20000 g / mol, 22000 g / mol, 25000 g / mol, 30000 g / mol, 32000 g / mol, 35000 g / mol, or 40000 g / mol. Further, the weight-average molecular weight of the water-soluble polymer is between 500 g / mol and 30000 g / mol.

[0093] In one embodiment, the water-soluble polymer is selected from allyl polyethylene glycol monomethyl ether. Further, the weight-average molecular weight is 400 g / mol to 40000 g / mol. Even further, the weight-average molecular weight is 500 g / mol to 30000 g / mol.

[0094] In one embodiment, the water-soluble polymer is selected from allyl polyvinyl alcohol. Further, the weight-average molecular weight is 400 g / mol to 40000 g / mol. Even further, the weight-average molecular weight is 500 g / mol to 30000 g / mol.

[0095] In one embodiment, the method for preparing the water-soluble polymer includes the following steps:

[0096] The water-soluble polymer is dissolved in a solvent (such as tetrahydrofuran), and allyl bromide is added. The molar ratio of the water-soluble polymer to allyl bromide is controlled at 1:(1-1.5). The solvent is removed after reacting for 20-30 hours.

[0097] In one embodiment, the water-soluble polymer is allyl polyethylene glycol monomethyl ether, and the preparation method includes the following steps:

[0098] Dissolve 0.5 mmol to 1 mmol of polyethylene glycol monoalkyl ether in 100 mL of tetrahydrofuran, add 0.5 mmol to 1 mmol of allyl bromide, and control the molar ratio of polyethylene glycol monoalkyl ether to allyl bromide to be the same. After reacting for 24 h, remove the solvent by vacuum distillation.

[0099] In one embodiment, the water-soluble polymer is allyl polyvinyl alcohol, and the preparation method includes the following steps:

[0100] Dissolve 0.5 mmol to 1 mmol of polyvinyl alcohol in 100 mL of tetrahydrofuran, add 0.5 mmol to 1 mmol of allyl bromide, and control the molar ratio of polyvinyl alcohol to allyl bromide to be the same. After reacting for 24 h, remove the solvent by vacuum distillation.

[0101] In one embodiment, the molar ratio of the water-soluble polymer to the modified palladium-containing polyoxometalate is (0.5 to 2):1, including but not limited to 0.5:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1.

[0102] In one embodiment, the molar ratio of the total amount of the water-soluble polymer and the modified palladium-containing polyoxometalate to the initiator is 1:(0.001 to 0.1), including but not limited to 1:0.001, 1:0.005, 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09 or 1:0.1.

[0103] In one embodiment, the initiator is selected from at least one of azobisisobutyronitrile and benzoin ether.

[0104] In one embodiment, the parameters of the graft copolymerization reaction include:

[0105] The temperature ranges from 0℃ to 40℃, and the time ranges from 4h to 50h.

[0106] Understandably, the temperature of the graft copolymerization reaction includes, but is not limited to, 0°C, 2°C, 5°C, 10°C, 12°C, 15°C, 17°C, 20°C, 22°C, 25°C, 27°C, 30°C, 32°C, or 40°C. Preferably, the temperature of the graft copolymerization reaction is 15°C to 40°C. Further, the temperature of the graft copolymerization reaction is 20°C to 40°C.

[0107] Understandably, the graft copolymerization reaction time includes, but is not limited to, 4h, 8h, 10h, 12h, 14h, 18h, 20h, 24h, 28h, 30h, 34h, 38h, 40h, 44h, 42h, 45h, 48h, or 50h. Preferably, the graft copolymerization reaction time is 8h to 40h. Further, the graft copolymerization reaction temperature is 10h to 30h.

[0108] In one embodiment, the preparation of the palladium-grafted polymer by mixing a water-soluble polymer with a palladium-containing polyoxometalate and an initiator via a graft copolymerization reaction includes the following steps:

[0109] 1 mmol to 2 mmol of modified palladium-containing polyoxometalate and 1 mmol to 2 mmol of water-soluble polymer were added to 5 mL to 200 mL of N,N-dimethylformamide. An initiator with a total molar percentage of 0.1% to 10% of the modified palladium-containing polyoxometalate and water-soluble polymer was added. The reaction was carried out at room temperature (e.g., 20±10℃) for 20 to 30 hours. After centrifugation, the precipitate was dried under vacuum to obtain the product, which is a water-soluble organic hybrid polyoxometalate. The initiator was selected from at least one of azobisisobutyronitrile and benzoin ether.

[0110] The present invention also provides a palladium activating solution, which includes a solvent and a palladium-containing grafted polymer as described above, or a palladium-containing grafted polymer prepared according to the preparation method described above.

[0111] In one embodiment, the concentration of the palladium-grafted polymer in the palladium activation solution is 0.01 mM to 0.05 mM. The activation solution with a low palladium ion concentration has both excellent stability and reduced cost.

[0112] In one embodiment, the solvent is water.

[0113] In one embodiment, the pH of the palladium activation solution is 5 to 7, including but not limited to 5, 5.5, 6, 6.5 or 7.

[0114] In one embodiment, the palladium activating solution further includes a pH adjuster.

[0115] In one embodiment, the pH adjuster is selected from at least one of boric acid, hydrochloric acid, phosphoric acid, sulfuric acid, ammonium chloride, ammonia, acetic acid, sodium hydroxide, and potassium hydroxide.

[0116] The present invention also provides a method for preparing the palladium activation solution as described above, comprising the following steps:

[0117] Dissolve 0.01 mmol to 0.05 mmol of palladium-grafted polymer in 1 L of water.

[0118] In one embodiment, the method for preparing the palladium activation solution as described above further includes the step of adjusting the pH of the palladium activation solution to 5-7 using a pH adjuster.

[0119] The present invention also provides the application of the palladium activating solution as described above in electroless plating.

[0120] In one embodiment, the application is the step of using the palladium activating solution to activate a non-metallic material surface.

[0121] In one embodiment, the application method includes the following steps:

[0122] Degreasing, pre-dipping, activation, reduction, and electroless plating;

[0123] The activation solution used in the activation step includes the palladium activation solution described above in this invention.

[0124] In one embodiment, the application method includes the following steps:

[0125] (1) Degreasing: Use alkaline degreasing;

[0126] (2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalate, and the remaining composition is the same as that of the activation solution;

[0127] (3) Activation: Activation is carried out using palladium activation solution at an activation temperature of 20℃~60℃ and an activation time of 0.5min~5min;

[0128] (4) Reduction: Reduction temperature 20℃~30℃, reduction time 0.5min~2min;

[0129] (5) Chemical plating: Seed layer of copper or nickel.

[0130] The following description, in conjunction with specific embodiments and comparative examples, provides further details.

[0131] The room temperature in the following examples and comparative examples is 22℃±5℃.

[0132] The reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd. has borides as its main active ingredient.

[0133] The reducing agent B provided by Guangdong Dongshuo Technology Co., Ltd. has borides as its main active ingredient.

[0134] The SIP system for nickel melting provided by Guangdong Dongshuo Technology Co., Ltd. mainly consists of nickel salts, reducing agents, and complexing agents.

[0135] The copper-reducing IC packaging system provided by Guangdong Dongshuo Technology Co., Ltd. mainly consists of copper salts, reducing agents, and complexing agents.

[0136] Example 1

[0137] (1) Preparation of palladium-grafted polymers:

[0138] Preparation of product A([Pd II 13 As V 8O 34 (OH)6] 8- PdCl2 and As2O5 (Pd / As molar ratio of (1.6-1.7):1) were dissolved in NaAc buffer solution (0.5M, pH=6.1), the solution was stirred and heated to 80℃ for 90 minutes, then the reaction solution was cooled to room temperature and filtered. The solution was slowly evaporated at room temperature for 16 hours to obtain product A.

[0139] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of mercaptotrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0140] 0.5 mmol of polyethylene glycol monoalkyl ether (weight average molecular weight of 500 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0141] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0142] (2) Preparation of palladium activation solution:

[0143] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add 0.1 M sodium hydroxide to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0144] (3) Application: Electroless nickel plating on the surface of FR-4 resin board, the steps are as follows:

[0145] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0146] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0147] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0148] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0149] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The surface of the FR-4 resin board was completely coated with nickel without any missed plating.

[0150] Example 2

[0151] (1) Preparation of palladium-grafted polymers:

[0152] Preparation of product A ([Cu II 2Pd II 22 P 12 O 60 (OH)8] 20- Pd3(CH3COO)6 (0.140 g, 0.208 mmol) and Cu(CH3COO)2·H2O (0.021 g, 0.104 mmol) (Pd / Cu molar ratio of 6:1) were dissolved in 0.5 M NaH2PO4 buffer (pH = 6.9). The reaction solution was heated to 80 °C for 1 hour with stirring, then cooled to room temperature, and filtered to obtain product A.

[0153] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of epoxytrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0154] 0.5 mmol of polyethylene glycol monoalkyl ether (weight average molecular weight of 500 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0155] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0156] (2) Preparation of palladium activation solution:

[0157] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add ammonia to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0158] (3) Application: Chemical copper plating on the surface of FR-4 resin board, the steps are as follows:

[0159] 1) Degreasing: Use degreasing agent CL provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0160] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0161] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0162] 4) Reduction: Use reducing agent B provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0163] 5) Chemical plating: Using the copper plating agent IC packaging system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and it was rinsed with water. The surface of the FR-4 resin board was completely coated with copper, with no missed plating.

[0164] Example 3

[0165] (1) Preparation of palladium-grafted polymers:

[0166] Preparation of product A([Pd 15 O 10 -(PO4) 10 ] 20- Pd(CH3COO)2 was placed in 0.5M NaH2PO4 buffer (pH 6.9), stirred and heated to 80℃ for 90 minutes, then filtered and cooled to room temperature, slowly evaporated for 1 day, filtered to collect crystals and air dried to obtain product A;

[0167] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of mercaptotrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0168] 0.5 mmol of polyethylene glycol monoalkyl ether (weight average molecular weight of 500 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0169] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0170] (2) Preparation of palladium activation solution:

[0171] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add boric acid and sodium hydroxide to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0172] (3) Application: Electroless nickel plating on EMC surfaces, the steps are as follows:

[0173] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0174] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0175] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0176] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0177] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The EMC surface was completely coated with nickel without any missed plating.

[0178] Example 4

[0179] (1) Preparation of palladium-grafted polymers:

[0180] Preparation of products A NaH2PO4-Na2HPO4 solution with pH 6.9 was added to Pd(OAc)2, the suspension was stirred vigorously and heated to 80°C for 90 minutes, cooled to room temperature and filtered, and the crystals were filtered and air-dried over two days to obtain product A.

[0181] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of aminotrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0182] 0.5 mmol of polyethylene glycol monoalkyl ether (weight-average molecular weight 500 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0183] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0184] (2) Preparation of palladium activation solution:

[0185] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add phosphoric acid and potassium hydroxide to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0186] (3) Application: Electroless copper plating on EMC surfaces, the steps are as follows:

[0187] 1) Degreasing: Use degreasing agent CL provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0188] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0189] 3) Activation: Use palladium activation solution, activation temperature 30℃, activation time 1 min, then wash with water;

[0190] 4) Reduction: Use reducing agent B provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0191] 5) Chemical plating: The IC packaging system using copper plating agent provided by Guangdong Dongshuo Technology Co., Ltd. was employed. The plating temperature was 40℃, the plating time was 14 minutes, and the product was rinsed with water. The EMC surface was completely coated with copper with no missed plating.

[0192] Example 5

[0193] (1) Preparation of palladium-grafted polymers:

[0194] Preparation of product A([Pd II 7V V 6O 24 (OH)2] 6- Pd(OAc)₂ and NaVO₃ (Pd / V molar ratio of 0.76:1) were added to a 2M KOAc (pH = 6.9) solution with stirring. The solution was heated to 80°C during the addition process. After heating for 15 minutes, NaOH solution (6M) was added to adjust the pH of the reaction mixture to 7.5. The reaction mixture was then heated and stirred at 80°C for 1 hour. The mixture was subsequently filtered to remove the insoluble dark brown precipitate of Pd(OH)₂. The resulting brown solution was cooled to room temperature and evaporated in a 25mL open beaker. The evaporation of the solution initially resulted in the formation of potassium decavanadate (K₆[V]). 10 O 28The formation of orange needle-like crystals of 1·nH2O is observed, which must be removed by filtration from time to time (once or twice a day); after 2 to 7 days, dark red crystals of 1 begin to form in the solution. These crystals are collected by filtration and washed with a mixture of acetone and water (9:1) to remove KOAc impurities, yielding product A.

[0195] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of mercaptotrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0196] 0.5 mmol of polyethylene glycol monoalkyl ether (weight average molecular weight of 500 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0197] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0198] (2) Preparation of palladium activation solution:

[0199] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add a pH adjuster to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0200] (3) Application: Electroless nickel plating on the surface of FR-4 resin board, the steps are as follows:

[0201] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0202] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0203] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0204] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0205] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The surface of the FR-4 resin board was completely coated with nickel without any missed plating.

[0206] Example 6

[0207] Preparation of product A([Pd II 2({H7Pd II 15 O 10 (PO4) 10}] 9- ): Add a NaH2PO4-Na2HPO4 solution with pH 6.9 to Pd(OAc)2, stir the suspension vigorously and heat to 80°C for 90 minutes, cool to room temperature and filter, filter the crystals and air dry within two days to obtain product A;

[0208] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of mercaptotrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0209] 0.5 mmol of polyethylene glycol monoalkyl ether (weight average molecular weight of 30000 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0210] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0211] (2) Preparation of palladium activation solution:

[0212] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add phosphoric acid and potassium hydroxide to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0213] (3) Application: Electroless nickel plating on the surface of FR-4 resin board, the steps are as follows:

[0214] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0215] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0216] 3) Activation: Use palladium activation solution, activation temperature 30℃, activation time 1 min, then wash with water;

[0217] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0218] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The surface of the FR-4 resin board was completely coated with nickel without any missed plating.

[0219] Example 7

[0220] Preparation of product A([Pd 15 O 10 -(PO4) 10 ] 20- Pd(CH3COO)2 was placed in 0.5M NaH2PO4 buffer (pH 6.9), stirred and heated to 80℃ for 90 minutes, then filtered and cooled to room temperature, slowly evaporated for 1 day, filtered to collect crystals and air dried to obtain product A;

[0221] 1 mmol of product A was dissolved in 100 ml of acetonitrile, 2 mmol of mercaptotrimethoxysilane was added, the mixture was refluxed for 14 hours, cooled to room temperature, and dried under vacuum to obtain product B.

[0222] 0.5 mmol of polyvinyl alcohol (weight average molecular weight of 1000 g / mol) was dissolved in 100 mL of tetrahydrofuran, and 0.5 mmol of allyl bromide was added. After reacting for 24 h, the solvent was removed by vacuum distillation to obtain product C.

[0223] 1 mmol of product B and 2 mmol of product C were added to 200 mL of N,N-dimethylformamide, and 0.5 mol% of azobisisobutyronitrile was added. The mixture was reacted at room temperature for 12 hours, centrifuged, and the precipitate was dried under vacuum to obtain the palladium-grafted polymer.

[0224] (2) Preparation of palladium activation solution:

[0225] Dissolve 0.02 mmol of palladium-grafted polymer in 1 L of water, then add ammonium chloride and ammonia to adjust the pH to 5-6 to obtain the palladium-activated solution.

[0226] (3) Application: Electroless nickel plating on the surface of FR-4 resin board, the steps are as follows:

[0227] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0228] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0229] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0230] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0231] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The surface of the FR-4 resin board was completely coated with nickel without any missed plating.

[0232] Comparative Example 1

[0233] (1) Preparation of palladium activation solution:

[0234] Dissolve 0.02 mmol of palladium chloride in 1 L of water, add 0.04 mmol of pyridine, and then add sodium hydroxide solution to adjust the pH to 7-8 to obtain the palladium activated solution.

[0235] (2) Application: Electroless nickel plating on the surface of FR-4 resin board, the steps are as follows:

[0236] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0237] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0238] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0239] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0240] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The surface of the FR-4 resin board was completely coated with nickel without any missed plating.

[0241] Comparative Example 2

[0242] (1) Preparation of product A([Pd 15 O 10 -(PO4) 10 ] 20- Pd(CH3COO)2 was placed in 0.5M NaH2PO4 buffer (pH 6.9), stirred and heated to 80℃ for 90 minutes, then filtered and cooled to room temperature. The mixture was slowly evaporated for 1 day, and the crystals were collected by filtration and air-dried to obtain product A.

[0243] (2) Preparation of palladium activation solution:

[0244] Dissolve 0.02 mmol of product A in 1 L of water, then add ammonium chloride and ammonia to adjust the pH to 5-6 to obtain the palladium activation solution.

[0245] (3) Application: Electroless nickel plating on the surface of FR-4 resin board, the steps are as follows:

[0246] 1) Degreasing: Use degreasing agent SC provided by Guangdong Dongshuo Technology Co., Ltd., degreasing temperature 50℃, degreasing time 3min, followed by water rinsing;

[0247] 2) Pre-soaking: The pre-soaking solution does not contain palladium polyoxometalates; its remaining composition is the same as the activation solution. Pre-soaking temperature: 25℃; Pre-soaking time: 1 min.

[0248] 3) Activation: Activate with palladium activation solution at 30℃ for 1 min, then wash with water;

[0249] 4) Reduction: Use reducing agent SR provided by Guangdong Dongshuo Technology Co., Ltd., reduction temperature 25℃, reduction time 1min, wash with water;

[0250] 5) Chemical plating: Using the SIP nickel plating system provided by Guangdong Dongshuo Technology Co., Ltd., the plating temperature was 40℃, the plating time was 14 minutes, and then rinsed with water. The surface of the FR-4 resin board was completely coated with nickel without any missed plating.

[0251] test:

[0252] (1) The palladium-containing grafted polymers prepared in Examples 1 to 7 were tested by gel chromatography and Fourier transform infrared spectroscopy. The results are shown in Table 1.

[0253] Table 1. Characterization results of palladium-grafted polymers

[0254]

[0255] As can be seen from Table 1, ~579cm -1 The absorption peak at ~665 cm⁻¹ is attributed to the Pd-O bonds in POM. -1 The absorption peak at ~1104 cm⁻¹ is attributed to the CS bond formed by the reaction of the silane coupling agent and the polymer. -1 The absorption peak at ~1250 cm⁻¹ is attributed to the Si-O bond in the silane coupling agent. -1 The absorption peak at ~1260 cm⁻¹ is attributed to the CO bonds in the polymer. -1 The absorption peak at that point is attributed to the CN bonds formed by the reaction of the silane coupling agent and the polymer. This indicates that POM was successfully grafted onto the polymer via the silane coupling agent.

[0256] (2) The performance changes of the activation solution during long-term use were tested, including the amount of palladium adsorbed on the resin surface and the appearance of the palladium activation solution. The results are shown in Table 2 below. The amount of palladium adsorbed on the resin surface was measured by the dissolution and volume adjustment method, and the appearance of the palladium activation solution was obtained by visual inspection.

[0257] Table 2. Performance changes of the activation solution during long-term use

[0258]

[0259] As shown in Table 2, compared with Comparative Example 1 and Comparative Example 2, the palladium activation solutions of Examples 1 to 7 of the present invention did not exhibit palladium absorption or turbidity during use, indicating better stability.

[0260] in addition, Figure 1 Images showing the metallization effect on the surface of FR-4 resin, including... Figure 1 Image 'a' shows the incoming resin material. Figure 1 Image b shows the effect of chemical nickel plating on the resin surface. Figure 1 Image c shows the effect of chemical copper plating on the resin surface. Figure 1 It can be seen that the activation solution containing palladium-grafted polymer successfully formed a metal coating on the resin surface, which is consistent with the characterization results in Table 2, indicating that the activation solution containing palladium-grafted polymer in this invention has the effect of catalytic electroless plating.

[0261] Figure 2 Images showing the surface metallization effect of EMC packaging materials, among which... Figure 2 Image 'a' is an EMC incoming material image. Figure 2 Image b shows the effect of electroless nickel plating on the EMC surface. Figure 2 Image c shows the effect of chemical copper plating on the EMC surface. Figure 2 It can be seen that the activation solution containing palladium-grafted polymer successfully formed a metal coating on the resin surface, which is consistent with the characterization results in Table 2, indicating that the activation solution containing palladium-grafted polymer in this invention has the effect of catalytic electroless plating.

[0262] Figure 3 The results show the appearance changes after using different palladium activation solutions for 3 months. Figure 1 a shows the appearance changes of the palladium activation solution in Example 1 after 3 months of use. Figure 1 b shows the appearance changes of Comparative Example 1's palladium activation solution after 3 months of use. Figure 3 It can be seen that the solution of Example 1 became clear after 3 months of use without any precipitate; however, the solution of Comparative Example 1 became turbid after 3 months of use, and precipitate was formed at the bottom of the beaker after standing. This indicates that Example 1 is more stable than Comparative Example 1.

[0263] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0264] The above-described embodiments are merely illustrative of several implementation methods of the present invention, facilitating a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A palladium activating solution, characterized in that, The invention includes a solvent and a palladium-grafted polymer, wherein the palladium-grafted polymer comprises a water-soluble polymer backbone and a palladium-containing polyoxometalate grafted onto the water-soluble polymer backbone. The method for preparing the palladium-grafted polymer includes the following steps: Preparation of palladium-containing polyoxometalates; The palladium-containing polyoxometalate was organically modified to prepare a modified palladium-containing polyoxometalate. The modified palladium-containing polyoxometalate was mixed with a water-soluble polymer and an initiator, and the palladium-containing grafted polymer was prepared by graft copolymerization. The modifier used in the organic modification step is a silane coupling agent.

2. The palladium activating solution according to claim 1, characterized in that, The palladium-containing polyoxometalate is selected from [Pd]. II 13 O8(LXO3)8] n- [Cu] II 2Pd II 22 P 12 O 60 (OH)8] 20- 、[Pd 15 O 10 -(PO4) 10 ] 20- 、[Pd II 2 {H7Pd II 15 O 10 (PO4) 10 }] 9- and [Pd] II 7V V 6O 24 (OH)2] 6- At least one of the following: Where X represents As V L represents O or a benzene ring, and n is taken from 5 to 10; or X represents Se IV L represents a lone pair, and n is taken from 5 to 10.

3. The palladium activating solution according to claim 1, characterized in that, The grafting rate of the palladium-containing polyoxometalate in the palladium-containing grafted polymer is 10% to 80%.

4. The palladium activating solution according to any one of claims 1 to 3, characterized in that, The weight-average molecular weight of the palladium-grafted polymer is 500 g / mol to 50000 g / mol.

5. The palladium activating solution according to any one of claims 1 to 3, characterized in that, The water-soluble polymer backbone is selected from at least one of polyethylene glycol monomethyl ether, polymaleic anhydride, polyvinyl alcohol, and polyacrylamide.

6. The palladium activating solution according to any one of claims 1 to 3, characterized in that, The water-soluble polymer and the palladium-containing polyoxometalate are linked by at least one of amino, thiol, and oxygen groups.

7. The palladium activating solution according to any one of claims 1 to 3, characterized in that, The preparation of palladium-containing polyoxometalates includes the following steps: Using metal salts and / or metal alkoxides as metal precursors, a sol is formed by hydrolysis, dehydration, de-alcoholization, and condensation. The sol is then converted into palladium-containing polyoxometalates by heating or solvent evaporation. The metal precursor includes a palladium salt.

8. The palladium activating solution according to any one of claims 1 to 3, characterized in that, Satisfy at least one of the following (1) to (2): (1) The molar ratio of the modifier used in the organic modification step to the palladium-containing polyoxometalate is (1-4):1; (2) The parameters for organic modification include: The temperature ranges from 20℃ to 100℃, and the time ranges from 2 hours to 16 hours.

9. The palladium activating solution according to any one of claims 1 to 3, characterized in that, Satisfy at least one of the following (1) to (5): (1) The molar ratio of the water-soluble polymer to the modified palladium-containing polyoxometalate is (0.5-2):1; (2) The total molar ratio of the water-soluble polymer and the modified palladium-containing polyoxometalate to the initiator is 1:(0.001~0.1). (3) The water-soluble polymer is selected from at least one of polyethylene glycol monomethyl ether, polymaleic anhydride, polyvinyl alcohol and polyacrylamide; (4) The initiator is selected from at least one of azobisisobutyronitrile and benzoin ether; (5) The parameters for the graft copolymerization reaction include: The temperature ranges from 0℃ to 40℃, and the time ranges from 4h to 50h.

10. The application of the palladium activating solution according to any one of claims 1 to 9 in electroless plating.

Images