Modified polyetherimide and preparation method thereof, and circuit board etching solution

Abstract

The invention provides modified polyetherimide, a preparation method of the modified polyetherimide and circuit board etching liquid. The modified polyetherimide contains ordered blocks formed by combining ethylene oxide (EO) groups and propylene oxide (PO) groups. The preparation method of the modified polyetherimide comprises the following steps: adding polyethyleneimine with a branched chain and a catalyst sodium hydroxide into a reaction kettle, stirring and heating, then adding an ethylene oxide (EO) monomer and a propylene oxide (PO) monomer for step-by-step reaction, and separating to obtain the modified polyetherimide, the circuit board etching solution comprises an etching base solution and modified polyetherimide. The modified polyetherimide improves the etching uniformity of the circuit board etching solution on the copper surface; the hydrophilic property is increased by embedding the ethylene oxide (EO) group, the wettability and the permeability are improved by embedding the propylene oxide (PO) group, the corrosion of the modified polyetherimide to the interior of copper is increased, and the etching and coarsening effect of the circuit board etching solution on the copper surface is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of circuit board production and manufacturing, and particularly to a modified polyetherimide, a preparation method thereof, and a circuit board etching solution. Background Art

[0002] The circuit board etching solution realizes roughening etching of the copper surface through chemical etching technology. Roughening etching of the copper surface is crucial in the manufacture of electronic devices, and the etching effect of the copper surface affects the electrical conductivity and surface adhesion of electrical connections. Most etching solutions are composed of strongly corrosive acidic components, and it is difficult to control their selectivity and rate during the etching process. The strong corrosive acidity of the etching solution and the use of heavy metals cause environmental pollution, and organic acids have a poor etching effect on the copper surface, and the roughening effect is poor with the same amount of etching solution used.

[0003] There is an urgent need to develop a new type of highly efficient and environmentally friendly etching solution additive to reduce the usage amount of acid and heavy metals in the etching solution, thereby reducing the usage cost and pollutant emissions. By grafting ethylene oxide (EO) and propylene oxide (PO) with polyethyleneimine, polyethyleneimine is modified to obtain a modified polyetherimide. The modified polyetherimide can significantly improve wettability and permeability, optimize its performance in the etching solution, thereby reducing the usage amount of the etching solution and achieving the corresponding roughening effect.

[0004] For example, a circuit board copper-removing solution and a circuit board copper-removing method disclosed in the comparative document CN202311330622.6. The circuit board copper-removing solution contains the following components: 5 - 20 g / L of hydrogen peroxide stabilizer, 105 - 155 g / L of copper-etching accelerator, 0.1 g - 20 g / L of surface copper-etching inhibitor, 5 g - 100 g / L of sulfuric acid, and 10 - 50 g / L of hydrogen peroxide; the copper-etching accelerator is selected from at least one of triethylenediamine, diethylenetriamine, hexamethylenetetramine, hexamethyleneimine, and polyethyleneimine. This solution contains effective components such as hydrogen peroxide stabilizer, copper-etching accelerator, and surface copper-etching inhibitor, which improves the system stability. However, the usage amounts of the copper-etching accelerator and sulfuric acid in the etching solution of this solution are relatively high, resulting in higher usage costs and larger pollutant emissions.

[0005] Another example is an organic acid etching solution and a method for using the same in circuit board manufacturing disclosed in the comparative document CN201811091808.X, which includes the following raw materials: organic acid, chloride salt, carboxylate salt, surfactant, and pure water; compared with the existing etching, the acidic etching used in this solution can effectively remove the oil stains, fingerprints, and oxide layers on the copper surface, obtaining a clean and uniform copper layer surface. At the same time, the etching rate of the organic acid etching solution is controllable, and copper layer surfaces with different roughness degrees can be obtained. However, the etching effect of the organic acid on the copper surface in this solution is poor, and the roughening effect is poor with the same amount of etching solution used. Summary of the Invention

[0006] The object of the present disclosure is to overcome the deficiencies in the prior art, and to provide a modified polyetherimide which can improve etching uniformity, wettability and permeability, enhance the etching roughening effect, reduce the usage amount of etching solution, as well as a preparation method thereof and a circuit board etching solution.

[0007] The object of the present disclosure is achieved by the following technical solutions:

[0008] A modified polyetherimide, the structural general formula of the modified polyetherimide is shown as follows,

[0009]

[0010] Wherein, the modified polyetherimide contains an ordered block composed of ethylene oxide (EO) groups and propylene oxide (PO) groups, and the ordered block is at least one of (EO)a(PO)b(EO)c, (PO)a(EO)b(PO)c, (EO)a(PO)b and (PO)a(EO)b.

[0011] In one embodiment, the molar ratio of the ethylene oxide (EO) group to the propylene oxide (PO) group is 2-3:1-2.

[0012] In one embodiment, the molecular weight of the modified polyetherimide is 90 kDa to 300 kDa.

[0013] A preparation method of a modified polyetherimide for preparing the modified polyetherimide in any of the above embodiments, comprising the following steps:

[0014] Add branched polyethyleneimine, catalyst sodium hydroxide and organic solvent into a reaction kettle for dissolution. After sealing the reaction kettle, introduce nitrogen to remove air and then perform vacuum pumping;

[0015] Stir and heat the reaction kettle, and raise the temperature to 100°C - 200°C to obtain a premixed polyethyleneimine solution;

[0016] Slowly add ethylene oxide (EO) monomer and propylene oxide (PO) monomer into the premixed polyethyleneimine solution for stepwise reaction, and the reaction time is 4 h - 15 h to obtain a modified polyetherimide solution;

[0017] Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

[0018] In one embodiment, the addition amount of the catalyst sodium hydroxide is 0.3% - 0.5%.

[0019] In one embodiment, adding ethylene oxide (EO) monomer and propylene oxide (PO) monomer slowly into the premixed polyethyleneimine solution includes the following steps:

[0020] In the premixed polyethyleneimine solution, first slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, and then slowly add the ethylene oxide (EO) monomer again, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or,

[0021] In the premixed polyethyleneimine solution, first slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, and then slowly add the propylene oxide (PO) monomer again, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or,

[0022] In the premixed polyethyleneimine solution, first slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or,

[0023] In the premixed polyethyleneimine solution, first slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the ethylene oxide (EO) monomer, control the reaction temperature until the pressure in the reaction kettle is stable.

[0024] In one embodiment, add branched polyethyleneimine and catalyst sodium hydroxide into the reaction kettle. After sealing the reaction kettle, introduce nitrogen to remove air. After performing vacuum pumping, stir and heat up the reaction kettle, and the following steps are further included:

[0025] Introduce nitrogen into the reaction kettle again and perform second vacuum pumping on the reaction kettle.

[0026] In one embodiment, the purities of both the ethylene oxide (EO) monomer and the propylene oxide (PO) monomer are greater than 99%.

[0027] A printed circuit board etching solution is prepared by using the modified polyetherimide obtained by the preparation method of the modified polyetherimide described in any of the above embodiments. The printed circuit board etching solution includes an etching base solution and the modified polyetherimide, and the concentration range of the modified polyetherimide in the printed circuit board etching solution is 0.0001 g / 100 ml - 0.1 g / 100 ml.

[0028] In one embodiment, the etching base solution includes the following mass components:

[0029]

[0030] Compared with the prior art, the present disclosure has at least the following advantages:

[0031] The above-mentioned modified polyetherimide has a structure of polyethyleneimine grafted with ethylene oxide (EO) groups and propylene oxide (PO) groups with branched chains. The ethylene oxide (EO) groups enhance the compatibility with the acidic aqueous printed circuit board etching solution, and the propylene oxide (PO) groups adsorb on the copper surface, slowing down the local etching rate and improving the roughness uniformity. The branched polyethyleneimine structure has abundant cations, making the binding and adsorption ability of the modified polyetherimide to the copper surface relatively strong. After the modified polyetherimide is added to the printed circuit board etching solution, the uniformity of the copper surface etching by the printed circuit board etching solution is improved; by embedding the propylene oxide (PO) groups, the wettability and permeability of the modified polyetherimide are improved. The addition of the modified polyetherimide to the printed circuit board etching solution increases the etching of the inside of the copper, improving the effect of the printed circuit board etching solution on the roughening of the copper surface; the roughening effect of the printed circuit board etching solution is significantly improved by the modified polyetherimide, reducing the usage amount of the printed circuit board etching solution, thereby reducing the usage cost and reducing pollutant emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a flow chart of the steps of the preparation method of the modified polyetherimide in one embodiment;

[0034] Figure 2 It is an electron microscope image of the printed circuit board copper surface treated with the printed circuit board etching solution of Embodiments 1-4;

[0035] Figure 3 It is an electron microscope image of the printed circuit board copper surface treated with the printed circuit board etching solution of Embodiments 5-7;

[0036] Figure 4 SEM image of the copper surface of the circuit board treated with the circuit board etching solution of the comparative example. Detailed implementation manners

[0037] For ease of understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the understanding of the disclosure content of the present disclosure is more thorough and comprehensive.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this disclosure belongs. The terms used in the specification of the present disclosure herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0040] To better understand the technical solutions and beneficial effects of the present disclosure, the present disclosure will be further described in detail below with specific embodiments:

[0041] Please refer to the modified polyetherimide of an embodiment of the present invention. The structural general formula of the modified polyetherimide is shown as follows.

[0042]

[0043] Among them, the modified polyetherimide contains an ordered block composed of ethylene oxide (EO) groups and propylene oxide (PO) groups, and the ordered block is (EO) a (PO) b (EO) c , (PO) a (EO) b (PO) c , (EO) a (PO) b and (PO) a (EO) b at least one of.

[0044] In this embodiment, the ethylene oxide (EO) group is the group formed after the ring opening of ethylene oxide, and its chemical formula is -CH2CH2O-. The propylene oxide (PO) group is the group formed after the ring opening of propylene oxide, and its chemical formula is -CH2CH(CH3)O-. The ethylene oxide (EO) group has strong hydrophilicity. Introducing the ethylene oxide (EO) group into the modified polyetherimide improves the hydrophilicity and wettability. The propylene oxide (PO) group has strong lipophilicity. Introducing the propylene oxide (PO) group into the modified polyetherimide improves the permeability.

[0045] It can be understood that the structure of the modified polyetherimide is formed by polymerization with branched polyethyleneimine as the initiator, so that the polyethyleneimine of the modified polyetherimide has abundant cations. The bonding of a large number of cations to the copper surface makes the binding and adsorption ability of the modified polyetherimide to the copper surface stronger.

[0046] It can be understood that the polyether structures of the ethylene oxide (EO) group and the propylene oxide (PO) group grafted on polyethyleneimine are divided into block polyethers and random polyethers. In the molecular chain of the random polyether, the ethylene oxide (EO) group and the propoxy group (PO) are randomly distributed, and the intermolecular force is weak. The grafted ordered block of the modified polyetherimide is a block polyether. The ethylene oxide (EO) group and the propylene oxide (PO) group of the block polyether are arranged neatly. According to the order of the blocks, molecular chains arranged neatly such as EPE type (EO-PO-EO), PEP type (PO-EO-PO), EP (EO-PO) or PE (PO-EO) can be formed respectively. The intermolecular force of the block polyether is stronger, making the permeability of the block polyether far superior to that of the random polyether. Even when the ethylene oxide (EO) group is located at the chain end, its permeability is still significantly higher than that of the random polyether.

[0047] It can be understood that after adding the modified polyetherimide to the printed circuit board etching solution, the etching of the copper inside by the modified polyetherimide increases. The modified polyetherimide has a strong binding and adsorption ability to the copper surface, and improves the wettability and permeability of the printed circuit board etching solution. As a result, the printed circuit board etching solution increases the etching of the copper inside, selectively etches the copper surface through adsorption and etching, making the roughening effect of the copper surface better, reducing the etching damage to the copper surface, reducing the usage amount of the printed circuit board etching solution, and having a better etching and roughening effect on the copper surface of the printed circuit board, reducing the usage cost of the printed circuit board etching and reducing the pollutant emissions.

[0048] The modified polyetherimide described above has a structure with branched polyethyleneimine grafted with ethylene oxide (EO) groups and propylene oxide (PO) groups. The ethylene oxide (EO) groups enhance the compatibility with acidic aqueous circuit board etching solutions. The propylene oxide (PO) groups adsorb on the copper surface, slowing down the local etching rate and improving the roughness uniformity. The branched polyethyleneimine structure has abundant cations, making the modified polyetherimide have a strong binding and adsorption ability to the copper surface. After adding the modified polyetherimide to the circuit board etching solution, the uniformity of the copper surface etching by the circuit board etching solution is improved; by embedding propylene oxide (PO) groups, the wettability and permeability of the modified polyetherimide are improved. Adding the modified polyetherimide to the circuit board etching solution increases the etching of the interior of the copper, improving the roughening effect of the circuit board etching solution on the copper surface; the roughening effect of the circuit board etching solution is significantly enhanced by the modified polyetherimide, reducing the usage amount of the circuit board etching solution, thereby reducing the usage cost and reducing pollutant emissions.

[0049] In one embodiment, the molar ratio of the ethylene oxide (EO) groups to the propylene oxide (PO) groups is 2 - 3:1 - 2. In this embodiment, when the proportion of the ethylene oxide (EO) groups is high, the hydrophilicity is increased, thus enhancing the compatibility with acidic chemical solutions. When the proportion of the propylene oxide (PO) groups is high, hydrophobic micelles are easily formed, adsorbing on the copper surface, slowing down the local etching rate and improving the roughness uniformity. By controlling the ratio of the ethylene oxide (EO) groups and the propylene oxide (PO) groups, the hydrophilic-lipophilic property, etching efficiency and roughening uniformity of the modified polyetherimide can be controlled.

[0050] In one embodiment, the molecular weight of the modified polyetherimide is from 90 kDa to 300 kDa. In this embodiment, when the molecular weight of the modified polyetherimide is less than 90 kDa, the molecular chain of the modified polyetherimide is short, and the stability of the modified polyetherimide is poor. The low-molecular-weight modified polyetherimide is more likely to degrade, resulting in uneven etching of the etching solution, thus affecting the precision of circuit board etching; when the molecular weight of the modified polyetherimide is greater than 300 kDa, the solubility of the modified polyetherimide decreases, and the formed solution has a high viscosity, hindering the effective contact between the etching reactants and the copper surface, reducing the etching rate. The high-molecular-weight modified polyetherimide is easy to form a gel in the etching solution, easily causing the etching solution to fail and increasing the production cost; when the molecular weight of the modified polyetherimide is from 90 kDa to 300 kDa, the modified polyetherimide has good solubility and stability in the etching solution. The modified polyetherimide improves the wettability between the etching solution and the circuit board copper surface, making the etching effect of the etching solution on the circuit board better.

[0051] As Figure 1As shown, in one embodiment, the present application further provides a method for preparing a modified polyetherimide for preparing the modified polyetherimide described in any of the above embodiments, including the following steps:

[0052] S101 Add branched polyethyleneimine, catalyst sodium hydroxide and organic solvent into the reaction kettle for dissolution. After closing the reaction kettle, introduce nitrogen to expel air and then perform vacuum pumping.

[0053] S103 Stir and heat the reaction kettle, raise the temperature to 100°C - 200°C to obtain a premixed polyethyleneimine solution.

[0054] S105 Slowly add ethylene oxide (EO) monomer or slowly add propylene oxide (PO) monomer to the premixed polyethyleneimine solution for stepwise reaction. The reaction time is 4h - 15h to obtain a modified polyetherimide solution.

[0055] S107 Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

[0056] In this embodiment, the branched polyethyleneimine is a high molecular polymer with a three-dimensional branched structure. Its molecular chain contains a large number of primary amine, secondary amine and tertiary amine groups, having high charge density, good water solubility and reactivity. The primary amine and secondary amine groups can graft with ethylene oxide (EO) groups or propylene oxide (PO) groups to form blocks; sodium hydroxide is used as a catalyst to cause the ethylene oxide (EO) monomer and propylene oxide (PO) monomer to initiate ring-opening reaction under alkaline conditions and at a temperature of 100°C - 200°C. The ethylene oxide (EO) monomer forms ethylene oxide (EO) groups, and the propylene oxide (PO) monomer forms propylene oxide (PO) groups. The ethylene oxide (EO) groups or propylene oxide (PO) groups can be grafted onto the branched polyethyleneimine to form a modified polyetherimide.

[0057] It can be understood that the boiling point of ethylene oxide (EO) monomer is about 11°C, and the boiling point of propylene oxide (PO) monomer is about 34°C. The boiling points of ethylene oxide (EO) monomer and propylene oxide (PO) monomer are relatively low. By closing the reaction kettle, the volatilization of ethylene oxide (EO) monomer and propylene oxide (PO) monomer is prevented. When the ethylene oxide (EO) monomer or propylene oxide (PO) monomer reacts completely, the pressure in the reaction kettle stabilizes to 0 Mpa.

[0058] The above-mentioned preparation method of modified polyetherimide prevents the volatilization of ethylene oxide (EO) monomer and propylene oxide (PO) monomer through a closed reaction kettle, thereby increasing the yield of modified polyetherimide; nitrogen is introduced to expel air, avoiding the interference of oxygen and moisture in the air on the reaction process, so that the obtained modified polyetherimide has a relatively high purity; by using branched polyethyleneimine as the initiator and sodium hydroxide as the catalyst, the branched polyethyleneimine reacts step by step with ethylene oxide (EO) monomer and propylene oxide (PO) monomer, and a modified polyetherimide with specific structures of ethylene oxide (EO) groups and propylene oxide (PO) groups can be obtained, thereby improving the wettability and permeability of the modified polyetherimide. Adding the modified polyetherimide to the circuit board etching solution increases the etching of the interior of copper and improves the effect of the circuit board etching solution on etching and roughening the copper surface.

[0059] Further, the organic solvent includes at least one of methanol, ethanol, DMF and THF. In this embodiment, the polar groups of the branched polyethyleneimine can be miscible with methanol and ethanol, which are lower alcohols. DMF is N,N-dimethylformamide, and the polar amine groups of the branched polyethyleneimine are compatible with the polar solvent of DMF. THF has medium polarity. When the branched polyethyleneimine has poor solubility in THF, THF can be mixed with methanol or ethanol to dissolve the branched polyethyleneimine.

[0060] The modified polyetherimide solution is separated by the precipitation method and dried in a vacuum environment to obtain the modified polyetherimide, including the following steps:

[0061] S1071 Filter the modified polyetherimide solution after the reaction to obtain a purified modified polyetherimide solution. Filter the purified modified polyetherimide solution through a 0.45 μm filter membrane to remove insoluble impurities in the modified polyetherimide solution, thereby improving the purity of the modified polyetherimide.

[0062] S1073 Slowly add acetone to the purified modified polyetherimide solution and perform magnetic stirring for 10 - 30 minutes until the precipitation is complete to obtain a modified polyetherimide precipitate. The volume ratio of acetone to the modified PEI solution is 1:3 - 5, and the rotation speed of the magnetic stirring is 200 rmp - 300 rmp to ensure the smooth precipitation of the modified polyetherimide precipitate.

[0063] S1075 Filter the modified polyetherimide precipitate through a Buchner funnel or a sintered glass funnel.

[0064] S1077 Wash the precipitated modified polyetherimide after suction filtration with acetone to obtain the washed modified polyetherimide precipitate. By washing the modified polyetherimide precipitate with acetone, the modified polyetherimide precipitate can be washed 2 - 3 times to remove residual catalysts or small molecule products in the modified polyetherimide precipitate.

[0065] S1079 Vacuum dry the washed modified polyetherimide precipitate to obtain modified polyetherimide. The drying temperature for vacuum drying is 40°C - 50°C, the vacuum degree is less than 10 Pa, and it is dried for 24 hours until a constant weight is achieved, so that the obtained modified polyetherimide has a better drying effect and higher purity.

[0066] In this embodiment, the modified polyetherimide after modification has a relatively high solubility in a specific solvent. However, after adding a poor solvent, such as a precipitant, such as acetone, ethanol, ether, etc., the solubility of the modified polyetherimide drops sharply, resulting in precipitation. Unreacted small molecules, such as residual EO / PO, catalysts, etc., remain in the solution and are separated by centrifugation or filtration, thereby obtaining modified polyetherimide with higher purity.

[0067] In one of the embodiments, the addition amount of the catalyst sodium hydroxide is 0.3% - 0.5%. In this embodiment, the epoxyethane (EO) monomer has relatively high activity. When the addition amount of sodium hydroxide is greater than 0.1%, ring - opening polymerization reaction occurs. However, due to the relatively low activity of the propylene oxide (PO) monomer, when the addition amount of sodium hydroxide is greater than 0.3%, the propylene oxide (PO) monomer undergoes ring - opening polymerization. The addition amount of the catalyst sodium hydroxide is 0.3%, and both the epoxyethane (EO) monomer and the propylene oxide (PO) monomer can undergo ring - opening polymerization. When the addition amount of the catalyst sodium hydroxide is greater than 0.5%, when sodium hydroxide is in excess, trace moisture reacts with the epoxide to form diol impurities such as ethylene glycol EG or propylene glycol PG. The excess NaOH will accelerate the hydrolysis reaction, resulting in an increase in the diol content. The addition amount of the catalyst sodium hydroxide is 0.3% - 0.5%.

[0068] In one of the embodiments, in the premixed polyethyleneimine solution, slowly adding the epoxyethane (EO) monomer or the propylene oxide (PO) monomer for a step - by - step reaction includes the following steps:

[0069] In the premixed polyethyleneimine solution, first slowly add the epoxyethane (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, and then slowly add the epoxyethane (EO) monomer again, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or,

[0070] In the premixed polyethyleneimine solution, slowly add the propylene oxide (PO) monomer first, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, and then slowly add the propylene oxide (PO) monomer again, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or,

[0071] In the premixed polyethyleneimine solution, slowly add the ethylene oxide (EO) monomer first, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or,

[0072] In the premixed polyethyleneimine solution, slowly add the propylene oxide (PO) monomer first, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the ethylene oxide (EO) monomer, and control the reaction temperature until the pressure in the reaction kettle is stable. In this embodiment, by means of stepwise reaction, grafted propylene oxide (PO) groups and ethylene oxide (EO) groups are sequentially obtained for the modified polyetherimide. By controlling the addition sequence of the propylene oxide (PO) monomer and the ethylene oxide (EO) monomer, modified polyetherimides with different ordered segments are obtained, thereby affecting the structure and properties of the modified polyetherimide, and endowing the modified polyetherimide with hydrophilicity and good wettability. In the premixed polyethyleneimine solution, two-stage or three-stage stepwise reactions are carried out. The reaction time of the propylene oxide (PO) monomer in each stage of the stepwise reaction is 2 h - 5 h, and the reaction time of the ethylene oxide (EO) monomer in each stage of the stepwise reaction is 2 h - 5 h, so that the ethylene oxide (EO) monomer or the propylene oxide (PO) monomer reacts completely.

[0073] In one embodiment, add branched polyethyleneimine and the catalyst sodium hydroxide into the reaction kettle. After sealing the reaction kettle, introduce nitrogen to expel air. After performing vacuum pumping, stir and heat up the reaction kettle. The following steps are further included:

[0074] Introduce nitrogen into the reaction kettle again and perform a second vacuum pumping on the reaction kettle. In this embodiment, after the first vacuum pumping, there may be trace amounts of air remaining in the reaction kettle. Introducing nitrogen again can displace and expel the remaining air, further reducing the oxygen content, avoiding side reactions of oxidation of the propylene oxide (PO) monomer and the ethylene oxide (EO) monomer with oxygen under high-temperature conditions, ensuring the stability of the generated modified polyetherimide, and thus improving the purity of the obtained modified polyetherimide.

[0075] In one embodiment, the purity of both the ethylene oxide (EO) monomer and the propylene oxide (PO) monomer is greater than 99%. In this embodiment, the high-purity ethylene oxide (EO) monomer and propylene oxide (PO) monomer can reduce the side reactions between impurities and polyethyleneimine, thereby improving the purity of the produced modified polyetherimide; adding the high-purity ethylene oxide (EO) monomer and propylene oxide (PO) monomer can precisely control the block ratio, so that the obtained modified polyetherimide has the expected hydrophilicity and wettability, reducing the impurity content of the modified polyetherimide, thereby improving the stability of the modified polyetherimide.

[0076] This application also provides a circuit board etching solution, which is configured with the modified polyetherimide obtained by using the preparation method of the modified polyetherimide in any of the above embodiments. The circuit board etching solution includes an etching base solution and a modified polyetherimide, and the concentration range of the modified polyetherimide in the etching solution is 0.0001 g / 100 ml - 0.1 g / 100 ml. In this embodiment, the etching base solution is liquid, the modified polyetherimide is solid, the modified polyetherimide has good hydrophilicity, and the etching base solution is an aqueous system. The circuit board etching solution is obtained by dissolving the modified polyetherimide in the etching base solution. The modified polyetherimide makes the circuit board etching solution have good wettability and permeability.

[0077] For the above circuit board etching solution, by adding the modified polyetherimide to the etching base solution, the wettability and permeability of the circuit board etching solution to the copper surface are significantly improved, enabling the circuit board etching solution to better penetrate into the interior of the copper surface for etching, thereby improving the etching rate and the effect of etching roughening of the circuit board etching solution on the copper surface of the circuit board.

[0078] In one embodiment, the etching base solution includes the following mass components:

[0079]

[0080] In this embodiment, formic acid is used as the main etchant to provide H + ions to participate in the redox reaction and promote metal dissolution; sodium formate is used as a buffer to stabilize the solution pH value and prevent excessive decomposition of formic acid; acetic acid can assist in adjusting the acidity of the etching base solution and enhance the etching uniformity. In some cases, acetic acid can replace part of the formic acid to control the reaction rate; ammonium acetate provides NH 4+ ions, NH 4+ forms a complex with metal ions to enhance the dissolution ability of the etching solution for metals and promote the dissolution of metal ions. Ammonium acetate dissociates into CH3COO - and NH 4+, forming a buffer system with acetic acid to further stabilize the pH; NaCl increases the ionic strength of the solution, improves the conductivity, and promotes the etching reaction; CuCl2·2H2O acts as an oxidant to provide Cu 2+ ions participate in the redox cycle, accelerating the metal dissolution. The prepared etching base solution has good stability and good etching performance.

[0081] It can be understood that the etching base solution system does not contain strongly corrosive acidic components. By adjusting the ratio of the etching base solution, its selectivity and rate can be controlled, but the corrosiveness of the etching base solution system decreases, affecting the roughening effect of the etching base solution on the copper surface; by adding modified polyetherimide to the etching base solution, the modified polyetherimide significantly improves the wettability and permeability of the printed circuit board etching solution to the copper surface, making the etching effect and roughening effect of the printed circuit board etching solution on the copper surface improved, thereby reducing the usage amount of the printed circuit board etching solution, and further reducing the usage cost and reducing the emission of pollutants.

[0082] Compared with the prior art, the present disclosure has at least the following advantages:

[0083] The above-mentioned modified polyetherimide and its preparation method, as well as the printed circuit board etching solution, the modified polyetherimide has a structure of polyethyleneimine grafted with ethylene oxide (EO) groups and propylene oxide (PO) groups with branches. The branched polyethyleneimine structure has abundant cations, making the contact surface between the modified polyetherimide and the copper surface stronger; by embedding ethylene oxide (EO) groups, the hydrophilicity of the modified polyetherimide is increased, improving the compatibility of the modified polyetherimide with the aqueous printed circuit board etching solution. By embedding propylene oxide (PO) groups, the wettability and permeability of the modified polyetherimide are improved, increasing the contact area between the modified polyetherimide and the copper surface, and improving the etching and roughening effect of the printed circuit board etching solution on the copper surface; by the modified polyetherimide, the roughening effect of the printed circuit board etching solution is significantly improved, reducing the usage amount of the printed circuit board etching solution, thereby reducing the usage cost and reducing pollutant emissions.

[0084] The following are some specific examples. If %, it means by weight percentage. It should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples can be obtained from commercial channels without special instructions.

[0085] It should be noted that first prepare the etching base solution for standby. Put 4000 mL of water into a beaker, add 1000 mL of formic acid and stir well. Weigh 800 g of copper chloride and stir it. Then add 200 mL of acetic acid, and then add 1200 g of ammonium acetate and 600 g of sodium formate in sequence. Add water to make up, and stir for 30 minutes to obtain 20 L of etching base solution.

[0086] Example 1

[0087] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and conduct a second evacuation. Stir the reactor, slowly heat up to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 1 mL of ethylene oxide (EO) monomer into the premixed polyethyleneimine solution, react for 2 h until the pressure in the reactor stabilizes at 0 MPa. Then slowly add 3 mL of propylene oxide (PO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa. Then slowly add 1 mL of ethylene oxide (EO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

[0088] Add 0.02 g of the modified polyetherimide into 1000 mL of the etching base solution to obtain a circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0089] Example 2

[0090] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and conduct a second evacuation. Stir the reactor, slowly heat up to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 1 mL of propylene oxide (PO) monomer into the premixed polyethyleneimine solution, react for 2 h until the pressure in the reactor stabilizes at 0 MPa. Then slowly add 3 mL of ethylene oxide (EO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa. Then slowly add 3 mL of propylene oxide (PO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

[0091] Add 0.02 g of the modified polyetherimide into 1 L of the etching base solution to obtain a circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0092] Example 3

[0093] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and conduct a second evacuation. Stir the reactor, slowly heat up to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 2 mL of ethylene oxide (EO) monomer into the premixed polyethyleneimine solution, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, then slowly add 1 mL of propylene oxide (PO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

[0094] Add 0.02 g of the modified polyetherimide into 1000 mL of the etching base solution to obtain a circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0095] Example 4

[0096] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and conduct a second evacuation. Stir the reactor, slowly heat up to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 2 mL of propylene oxide (PO) monomer into the premixed polyethyleneimine solution, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, then slowly add 1 mL of ethylene oxide (EO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

[0097] Add 0.02 g of the modified polyetherimide into 1000 mL of the etching base solution to obtain a circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0098] Example 5

[0099] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and perform a second evacuation. Stir the reactor and slowly heat it to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 2 mL of ethylene oxide (EO) monomer to the premixed polyethyleneimine solution, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, then slowly add 1 mL of propylene oxide (PO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain modified polyetherimide.

[0100] Take 500 mL of etching base solution, dilute it with water to 1000 mL, and add 0.02 g of modified polyetherimide to the diluted 1000 mL of etching base solution to obtain a printed circuit board etching solution with a modified polyetherimide concentration of 0.001 g / 100 ml.

[0101] Example 6

[0102] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and perform a second evacuation. Stir the reactor and slowly heat it to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 0.5 mL of ethylene oxide (EO) monomer to the premixed polyethyleneimine solution, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, then slowly add 0.25 mL of propylene oxide (PO) monomer, react for 2 h until the pressure in the reactor stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain modified polyetherimide.

[0103] Add 0.02 g of modified polyetherimide to 1000 mL of etching base solution to obtain a printed circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0104] Example 7

[0105] Add 100 g of branched polyethyleneimine with a molecular weight of 70,000, 0.5 g of catalyst NaOH, and 500 mL of methanol into a high-temperature and high-pressure reactor. Seal the reactor well, introduce nitrogen to displace air, then evacuate, introduce nitrogen again, and conduct a second evacuation. Stir the reactor, slowly heat up to the reaction temperature of 120 °C to obtain a premixed polyethyleneimine solution. Slowly add 10 mL of ethylene oxide (EO) monomer to the premixed polyethyleneimine solution, react for 2 h until the reactor pressure stabilizes at 0 MPa, then slowly add 5 mL of propylene oxide (PO) monomer, react for 2 h until the reactor pressure stabilizes at 0 MPa, and continue to react for 1.5 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain modified polyetherimide.

[0106] Add 0.02 g of modified polyetherimide into 1000 mL of etching base solution to obtain a printed circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0107] Comparative Example 1

[0108] Take 1 L of etching base solution as the printed circuit board etching solution.

[0109] Comparative Example 2

[0110] Add 0.02 g of polyethyleneimine PEI into 1000 mL of etching base solution to obtain a printed circuit board etching solution with a modified polyetherimide concentration of 0.002 g / 100 ml.

[0111] Table 1 Performance Test of Printed Circuit Board Etching Solution

[0112]

[0113] It should be noted that the etching rate test includes the following steps:

[0114] Use a 3 * 5 cm double-sided copper clad laminate, immerse the double-sided copper clad laminate in the prepared etching solution for 60 s, measure the mass change to calculate the etching rate.

[0115] It should be noted that the surface roughness test includes the following steps:

[0116] Use a scanning electron microscope (SEM) to analyze the surface roughness of the etched copper surface. Use a white light interferometer to test the surface roughness of the board surface, where Ra is the arithmetic mean deviation of the profile and Rz is the average height of the micro-irregularities.

[0117] As Figures 2 to 4 shown, Figure 2 from top to bottom are the electron micrographs of Example 1, Example 2, Example 3, and Example 4; Figure 3From top to bottom are the electron micrographs of Example 5, Example 6, and Example 7; Figure 4 From top to bottom are the electron micrographs of Comparative Example 1 and Comparative Example 2.

[0118] From Figures 2 to 4 and Table 1, it can be seen that compared with Comparative Example 1 and Comparative Example 2, Examples 1-7:

[0119] Figure 4 The surface of Comparative Example 1 is relatively flat, the etching rate of Comparative Example 1 is faster, the damage to the copper surface is greater, and the roughening effect of Comparative Example 1 is poorer. Figure 4 The polyetherimide etching of Comparative Example 2 has better uniformity, but the roughness Ra and roughness Rz of Comparative Example 2 are smaller, and the roughening effect of Comparative Example 2 is poorer.

[0120] Examples 1-7 have higher roughness of the etched copper surface, indicating that after adding modified polyetherimide, the hydrophilicity of PEI is increased by embedding EO, the wettability of the modified polyetherimide is improved, and the contact area with the copper surface is increased, so that the circuit board etching solution can better penetrate into the copper surface and etch, and the roughening effect of the circuit board etching solution on the circuit board copper surface is better.

[0121] Compared with Examples 1-5, Figure 3 and Figure 4 Examples 3 and 5 have better etching uniformity. The etching roughening effect of Example 3 is the best. The concentration of the modified polyetherimide added in Example 5 is 50% of that in Example 3, indicating that the concentration of the modified polyetherimide and the molar ratio of different ethylene oxide (EO) groups to propylene oxide (PO) groups will affect the roughening effect of the circuit board etching solution.

[0122] Compared with Example 3 and Example 4, Example 4 has more propylene oxide (PO) groups. The etching rate of Example 4 is lower and the roughness Rz is lower, and the etching rate is slower, indicating that the propylene oxide (PO) group can adsorb on the copper surface and slow down the local etching rate, thereby affecting the roughening effect of the circuit board etching solution.

[0123] Comparing Example 3, Example 6, and Example 7, it can be seen that Example 6 has fewer ethylene oxide (EO) groups and propylene oxide (PO) groups. The roughness Rz of Example 6 relative to Example 3 is smaller. The permeability and etching ability of the modified polyetherimide in Example 6 to the copper surface are reduced, resulting in a poorer roughening effect of the circuit board in Example 6; Example 7 has more ethylene oxide (EO) groups and propylene oxide (PO) groups. The roughness Rz of Example 7 relative to Example 3 is smaller, and the etching rate is lower. The modified polyetherimide covering the copper surface hinders the etching of the copper surface, and the etching amount of Example 7 is small, resulting in a poorer roughening effect of Example 7.

[0124] The above-described embodiments merely represent several implementation manners of the present disclosure. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the disclosed patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several variations and improvements can still be made, and these all fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.

Claims

1. A modified polyetherimide, characterized in that, The structural general formula of the modified polyetherimide is as follows: The modified polyetherimide contains an ordered block composed of ethylene oxide (EO) groups and propylene oxide (PO) groups, wherein the ordered block is (EO) a (PO) b (EO) c 、(PO) a (EO) b (PO) c , (EO) a (PO) b and (PO) a (EO) b At least one of .

2. The modified polyetherimide according to claim 1, wherein The ratio of the ethylene oxide (EO) group to the propylene oxide (PO) group is 2 - 3:1 - 2.

3. The modified polyetherimide according to claim 1, wherein The molecular weight of the modified polyetherimide is 90 kDa to 300 kDa.

4. A preparation method of a modified polyetherimide, characterized in that, The method for preparing the modified polyetherimide according to any one of claims 1 - 3 includes the following steps: Add branched polyethyleneimine, catalyst sodium hydroxide and organic solvent into a reaction kettle for dissolution. After sealing the reaction kettle, introduce nitrogen to remove air and then perform vacuum pumping. Stir and heat up the reaction kettle, and raise the temperature to 100°C - 200°C to obtain a premixed polyethyleneimine solution. Slowly add ethylene oxide (EO) monomer and propylene oxide (PO) monomer to the premixed polyethyleneimine solution for stepwise reaction. The reaction time is 4 h - 15 h to obtain a modified polyetherimide solution. Separate the modified polyetherimide solution by precipitation method and dry it in a vacuum environment to obtain the modified polyetherimide.

5. The preparation method of the modified polyetherimide according to claim 4, characterized in that, The addition amount of the catalyst sodium hydroxide is 0.3% - 0.5%.

6. The preparation method of the modified polyetherimide according to claim 4, characterized in that, Slowly adding ethylene oxide (EO) monomer and propylene oxide (PO) monomer to the premixed polyethyleneimine solution includes the following steps: In the premixed polyethyleneimine solution, first slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, and then slowly add the ethylene oxide (EO) monomer again, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or, In the premixed polyethyleneimine solution, first slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, and then slowly add the propylene oxide (PO) monomer again, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or, In the premixed polyethyleneimine solution, first slowly add the ethylene oxide (EO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable; and / or, In the premixed polyethyleneimine solution, first slowly add the propylene oxide (PO) monomer, control the reaction temperature at 100°C - 200°C until the pressure in the reaction kettle is stable, then slowly add the ethylene oxide (EO) monomer, and control the reaction temperature until the pressure in the reaction kettle is stable.

7. The preparation method of the modified polyetherimide according to claim 4, wherein After adding branched polyethyleneimine and catalyst sodium hydroxide into the reaction kettle, sealing the reaction kettle, introducing nitrogen to remove air and performing vacuum pumping, stirring and heating up the reaction kettle also includes the following steps: Introduce nitrogen into the reaction kettle again and perform a second vacuum pumping on the reaction kettle.

8. The preparation method of the modified polyetherimide according to claim 4, characterized in that, The purity of both the ethylene oxide (EO) monomer and the propylene oxide (PO) monomer is greater than 99%.

9. A printed circuit board etching solution, characterized in that, The modified polyetherimide obtained by using the preparation method of the modified polyetherimide according to any one of claims 4-8 above is configured. The circuit board etching solution includes an etching base solution and a modified polyetherimide, and the concentration range of the modified polyetherimide in the circuit board is 0.0001 g / 100 ml - 0.1 g / 100 ml.

10. The circuit board etching solution according to claim 9, characterized in that, The etching base solution includes the following mass components:

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