Modified metal powder, method for producing the same, and metal conductive paste

Abstract

The application provides modified metal powder, a preparation method thereof and metal conductive paste. The preparation method of the modified metal powder comprises the following steps: mixing a hydroxyl-containing amphiphilic modifier and a hydrophobic modifier with a first solvent to obtain a modifier composition solution; and applying the modifier composition solution to the surface of metal powder with stirring to obtain modified metal powder. Thus, the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier can be uniformly distributed on the surface of the metal powder by using the method of mechanical chemical modification. The hydroxyl-containing amphiphilic modifier can improve the compatibility of the metal powder with the organic carrier in the conductive paste, and the hydrophobic modifier can improve the hydrophobicity of the metal powder, so that the metal powder is not easy to agglomerate and block. In addition, the method can simply and effectively adjust the polarity of the surface of the metal powder, thereby improving the dispersibility of the metal powder in the conductive paste, the adhesion of the conductive paste and the conductivity.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a modified metal powder and its preparation method, and a metal conductive slurry. Background Technology

[0002] Micro- and nano silver powder, copper powder, and silver-coated copper powder are used as fillers in low-temperature curing conductive pastes and need to be uniformly dispersed in an organic carrier. The most common method for preparing these metal powders is wet chemical synthesis. To maintain good dispersibility, water-soluble polymers or small molecules such as PVP (polyvinylpyrrolidone), PEG (polyethylene glycol), PVA (polyvinyl alcohol), CTAB (cetyltrimethylammonium bromide), PAA (polyacrylic acid), Tween, and gum arabic are added as dispersants during the synthesis process. In the post-processing of the powder, a certain amount of modifier is added for surface coating. Modifiers are mostly hydrophobic substances, such as long-chain fatty acids or esters like stearic acid, palmitic acid, oleic acid, linoleic acid, and cinnamic acid. The purpose of selecting hydrophobic long-chain fatty acids or esters is to form a hydrophobic layer on the powder surface, resulting in lower water content and increased surface lubricity. This prevents agglomeration and clumping during later drying and also reduces the likelihood of sintering and aggregation during pulverization and smoothing processes.

[0003] In the single-layer or multi-layer coating structure of metal powders, the polarity of the modifier, located on the outermost layer, determines the polarity characteristics of the metal powder. In existing wet modification processes, if modifiers of different polarities are mixed for wet modification, the two types of modifiers will separate and separate on the surface of the metal powder as the powder dries, making it impossible to adjust the surface polarity of the powder. For example, experiments have shown that using a mixture of PVA solution and stearic acid emulsion to modify the surface of silver powder, with a PVA to stearic acid ratio of 1:4, results in completely hydrophobic silver powder. Compared to silver powder modified using stearic acid emulsion alone, the silver powder prepared by this method exhibits the same hydrophobicity, except for a slightly larger loss on ignition.

[0004] In addition, existing technologies often use modifiers that have no or only one active group that can react with the curing agent. Therefore, the modified metal powder not only has very low surface polarity, but also has insufficient compatibility with acrylic resin, epoxy resin, phenolic resin, alkyd resin, etc., resulting in poor powder dispersibility. Furthermore, the strength of the prepared slurry electrode body and its adhesion to the substrate are relatively small.

[0005] Therefore, further research is needed on methods for modifying metal powders. Summary of the Invention

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a modified metal powder and its preparation method, as well as a conductive metal slurry. The method of this invention for preparing modified metal powder allows for adjustment of the surface polarity of the metal powder, making the prepared modified metal powder less prone to agglomeration and exhibiting good compatibility with the organic carrier in the conductive slurry, thus possessing good dispersibility.

[0007] In a first aspect, the present invention provides a method for preparing modified metal powder. According to an embodiment of the present invention, the method includes the following steps: (1) mixing a hydroxyl-containing amphiphilic modifier and a hydrophobic modifier with a first solvent to obtain a modifier composition solution; (2) applying the modifier composition solution to the surface of the metal powder while stirring to obtain the modified metal powder.

[0008] Therefore, the preparation method of the present invention first prepares a modifier composition solution by mixing a hydroxyl-containing amphiphilic modifier and a hydrophobic modifier, and then applies it to the surface of a stirred metal powder. By using a mechanochemical modification method, the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier can be uniformly distributed on the surface of the metal powder. The hydroxyl-containing amphiphilic modifier can improve the compatibility of the metal powder with the organic carrier in the conductive slurry, thereby making the metal powder uniformly dispersed in the conductive slurry. The hydrophobic modifier can improve the hydrophobicity of the metal powder, thereby reducing the water content of the metal powder, increasing the surface lubricity of the powder, and making it less prone to agglomeration during subsequent drying, thereby further improving the dispersibility of the metal powder in the conductive slurry. In addition, by using the above-mentioned mechanochemical modification method, the polarity of the metal powder surface can be changed simply and effectively by adjusting the mixing ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier, thereby improving the affinity and dispersibility of the metal powder with the organic carrier.

[0009] In addition, the method for preparing modified metal powder according to the above embodiments of the present invention may also have the following additional technical features:

[0010] According to an embodiment of the present invention, the mass ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier is 1:(4-19). This allows the modified metal powder to be more uniformly dispersed in the conductive slurry.

[0011] According to embodiments of the present invention, the hydroxyl-containing amphiphilic modifier molecule includes a hydrophobic group and at least two hydroxyl groups. This further improves the compatibility of the modified metal powder with the organic carrier, thereby enhancing its dispersibility in conductive slurries.

[0012] According to embodiments of the present invention, the hydroxyl-containing amphiphilic modifier includes at least one of modified castor oil polyol, polyglycerol ester, Poloxamer 188, and polyethylene glycol-15-hydroxystearate.

[0013] According to an embodiment of the present invention, the hydrophobic modifier comprises C6-C 22 Saturated fatty acids, C6-C 22 Unsaturated fatty acids, C6-C 22 Fatty acid glycerides, C6-C 22 fatty amines and C6-C 22 At least one of the fatty amides.

[0014] According to an embodiment of the present invention, the boiling point of the first solvent is not greater than 100°C. This allows the modified metal powder to be easily dried.

[0015] According to an embodiment of the present invention, the first solvent includes at least one of propanol, ethanol, methanol, and ethyl acetate.

[0016] According to an embodiment of the present invention, in step (2), the mass ratio of the total mass of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier in the modifier composition solution to the mass ratio of the metal powder is (1-20):1000, preferably (2-5):1000. This allows the metal powder to have better dispersibility and conductivity, thereby achieving a better coating modification effect.

[0017] According to an embodiment of the present invention, the mass concentration of the modifier composition solution is 1wt%-5wt%. Therefore, the modifier composition exhibits good dispersibility in the solvent, and applying the modifier composition solution to the surface of the metal powder can achieve a good coating modification effect.

[0018] According to an embodiment of the present invention, the volume average particle size Dv50 of the metal powder is 0.1 μm-5 μm. Metal powders within this particle size range are more suitable for modification using the mechanochemical method of the present invention, thereby achieving better modification results.

[0019] According to an embodiment of the present invention, the metal powder includes at least one of silver powder, copper powder, and silver-coated copper powder.

[0020] In a second aspect, the present invention provides a modified metal powder. According to an embodiment of the invention, the modified metal powder is prepared using the method described above. Therefore, the modified metal powder exhibits good dispersibility in conductive slurries and is not prone to agglomeration during drying.

[0021] In a third aspect, the present invention provides a metal conductive paste. According to an embodiment of the present invention, the metal conductive paste comprises modified metal powder, hydroxyl resin, curing agent, and a second solvent, wherein the modified metal powder is the modified metal powder described above.

[0022] Therefore, according to an embodiment of the present invention, in this conductive slurry, the surface of the modified metal powder is uniformly coated with a hydroxyl-containing amphiphilic modifier and a hydrophobic modifier. The hydroxyl-containing amphiphilic modifier can give the modified metal powder and the hydroxyl resin good compatibility, and the hydrophobic modifier can give the surface of the modified metal powder suitable hydrophobicity, thus preventing agglomeration. Thus, in this conductive slurry, the modified metal powder can be uniformly dispersed, thereby giving the conductive slurry good flowability and allowing the prepared electrode to have a low volume resistivity. In addition, the hydroxyl groups on the surface of the modified metal powder and the hydroxyl resin in the conductive slurry can both react with the curing agent, thereby improving the strength of the prepared electrode and the adhesion between the electrode and the substrate.

[0023] In addition, the metal conductive paste according to the above embodiments of the present invention may also have the following additional technical features:

[0024] According to an embodiment of the present invention, based on the total mass of the metal conductive paste, the mass percentage of the modified metal powder is 88wt%-95wt%, and the sum of the mass percentages of the hydroxyl resin and the curing agent is 2wt%-8wt%. This results in an electrode body with low resistivity and good strength and adhesion.

[0025] According to embodiments of the present invention, the hydroxyl resin includes at least one of polyvinyl acetal, phenolic resin, acrylic resin, modified acrylic resin, aldehyde-ketone resin, and phenoxy resin. This improves the strength and adhesion to the substrate of the prepared electrode.

[0026] According to embodiments of the present invention, the curing agent comprises at least one of isocyanate and amino resin. This improves the strength and adhesion to the substrate of the prepared electrode.

[0027] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0029] Figure 1This is a flowchart of the preparation of modified metal powder in one embodiment of the present invention. Detailed Implementation

[0030] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0031] In a first aspect, the present invention provides a method for preparing modified metal powder. According to an embodiment of the present invention, referring to… Figure 1 The method includes the following steps:

[0032] S100: Preparation of the modifier composition solution

[0033] In this step, a modifier composition solution is obtained by mixing a hydroxyl-containing amphiphilic modifier and a hydrophobic modifier with a first solvent. In the modifier composition solution, the hydroxyl-containing amphiphilic modifier can improve the compatibility between the metal powder and the organic carrier in the conductive slurry, thereby enabling the metal powder to be uniformly dispersed in the conductive slurry. The hydrophobic modifier can improve the hydrophobicity of the metal powder, thereby reducing the water content of the metal powder, increasing the surface lubricity of the powder, making it less prone to agglomeration and clumping during subsequent drying, and further improving the dispersibility of the metal powder in the conductive slurry.

[0034] During the preparation process, the mass ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier can be adjusted as needed, thereby adjusting the surface polarity of the modified metal powder.

[0035] For example, in some embodiments of the present invention, the organic carrier used to prepare the metal conductive paste includes at least one of polyvinyl acetal, phenolic resin, acrylic resin, modified acrylic resin, aldehyde-ketone resin, and phenoxy resin. To improve the compatibility between the modified metal powder and the aforementioned organic carrier, the mass ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier can be set within the range of 1:(4-19), such as 1:4, 1:5, 1:7, 1:9, 1:11, 1:13, 1:15, 1:17, 1:18, 1:19, etc. This allows the modified metal powder to be more uniformly dispersed in the conductive paste.

[0036] In some embodiments of the present invention, the hydroxyl-containing amphiphilic modifier molecule includes a hydrophobic group and at least two hydroxyl groups. The multiple hydroxyl groups in the amphiphilic modifier can further enhance the surface polarity of the modified metal powder, thereby further improving the compatibility of the modified metal powder with the organic carrier, and thus improving its dispersibility in conductive slurry. For example, in the present invention, the hydroxyl-containing amphiphilic modifier may include at least one of modified castor oil polyols (such as S310 modified castor oil and A4105 modified castor oil from Shanghai Jingri New Materials Technology Co., Ltd.), polyglycerol esters, Poloxamer 188 (H(C2H4O)a(C3H6O)b(C2H4O)aOH), and polyethylene glycol-15-hydroxystearate (Solutol HS15), wherein the polyglycerol ester is preferably triglyceride monostearate.

[0037] According to embodiments of the present invention, the hydrophobic modifier may include C6-C. 22 Saturated fatty acids, C6-C 22 Unsaturated fatty acids, C6-C 22 Fatty acid glycerides, C6-C 22 fatty amines and C6-C 22 At least one of the fatty amides. Coating the surface of metal powder with the above-mentioned hydrophobic modifiers can impart suitable hydrophobicity to the metal powder, thereby preventing it from agglomerating and further improving its dispersibility in conductive pastes. As an example, C6-C... 22 Saturated fatty acids can include, but are not limited to, long-chain carboxylic acids such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, cinnamic acid, palmitic acid, and stearic acid; C6-C 22 Unsaturated fatty acids can include, but are not limited to, fatty acids containing one or more double bonds, such as oleic acid, linoleic acid, linolenic acid, and arachidonic acid; C6-C 22 Fatty acid glycerides can include, but are not limited to, glyceryl monostearate, triglyceride stearate, and triglyceride oleate; C6-C 22 Aliphatic amines can include, but are not limited to, octylamine and oleylamine; C6-C 22 Fatty amides can include, but are not limited to, laurylamide and octadecylamide.

[0038] In some embodiments of the present invention, the mass concentration of the modifier composition solution can be 1wt%-5wt%, such as 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, etc. Using the above-mentioned mass concentrations of the modifier composition solution facilitates uniform dispersion of the modifier composition in the solvent. Simultaneously, the amount of solvent used in the above-mentioned mass concentrations of the modifier composition solution is relatively small, making it less likely for the metal powder to agglomerate after application. Thus, while reducing the amount of solvent used, good dispersibility of the metal powder can be ensured. Therefore, a better coating modification effect can be achieved.

[0039] In some embodiments of the present invention, the boiling point of the first solvent is not greater than 100°C. This allows the modified metal powder to be easily dried. For example, in the present invention, the first solvent may include at least one of propanol, ethanol, methanol, and ethyl acetate.

[0040] S200: Applying a modifier composition solution to the surface of metal powder.

[0041] In this step, the metal powder is first stirred and pulverized. Then, while stirring, the modifier composition solution prepared in step S100 is applied to the surface of the metal powder. After continuous treatment for a certain period of time, the metal powder is dried to obtain the modified metal powder of the present invention. By using the above-described mechanochemical modification method, the amphiphilic modifier containing hydroxyl groups and the hydrophobic modifier in the modifier composition solution can be uniformly distributed on the surface of the metal powder.

[0042] Before applying the modifier composition solution, in order to fully pulverize the metal powder, the stirring linear speed can be set to a range greater than 80 m / s. Then, during the application of the modifier composition solution, in order to more uniformly coat the surface of the metal powder, the stirring linear speed can be set to a range less than 20 m / s. Furthermore, the modifier composition solution can be sprayed into the stirred and dispersed metal powder using a nozzle. In this way, the modifier composition solution can be uniformly and appropriately coated on the surface of the metal powder.

[0043] In some embodiments of the present invention, the volume average particle size Dv50 of the metal powder can be 0.1 μm-5 μm, such as 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc., preferably 0.2 μm-5 μm. Metal powders within the above particle size range are more suitable for modification using the mechanochemical method of the present invention, thereby achieving better modification effects. Furthermore, the mechanochemical modification method of the present invention can be applied to the surface modification of various types of metal powders. For example, in the present invention, the metal powder may include at least one of silver powder, copper powder, and silver-coated copper powder.

[0044] In some embodiments of the present invention, the mass ratio of the total mass of the amphiphilic modifier and the hydrophobic modifier containing hydroxyl groups in the modifier composition solution to the mass ratio of the metal powder can be (1-20):1000, such as 1:1000, 2:1000, 5:1000, 7:1000, 9:1000, 12:1000, 16:1000, 20:1000, etc., preferably (2-5):1000. Using the above-mentioned mass ratio of modifier composition and metal powder is beneficial for giving the metal powder better dispersibility and conductivity, thereby achieving a better coating modification effect.

[0045] Therefore, the method for preparing modified metal powder of the present invention can make the amphiphilic modifier containing hydroxyl groups and the hydrophobic modifier uniformly distributed on the surface of the metal powder. Furthermore, the polarity of the surface of the metal powder can be changed simply and effectively by adjusting the mixing ratio of the amphiphilic modifier containing hydroxyl groups and the hydrophobic modifier, thereby improving the dispersibility of the modified metal powder in conductive slurry.

[0046] In a second aspect, the present invention provides a modified metal powder. According to an embodiment of the present invention, the modified metal powder is prepared by the method of the first aspect. Thus, the surface of the modified metal powder is uniformly coated with an amphiphilic modifier containing hydroxyl groups and a hydrophobic modifier, exhibiting good compatibility with the organic carrier and being less prone to agglomeration. Therefore, the modified metal powder can be more uniformly dispersed in the conductive slurry.

[0047] In a third aspect, the present invention provides a metal conductive paste. According to an embodiment of the present invention, the metal conductive paste comprises modified metal powder, hydroxyl resin, curing agent, and a second solvent.

[0048] The modified metal powder is the modified metal powder in the second aspect. As described in the second aspect, the surface of the modified metal powder is uniformly coated with a hydroxyl-containing amphiphilic modifier and a hydrophobic modifier. The hydroxyl-containing amphiphilic modifier can make the modified metal powder and the hydroxyl resin have good compatibility, and the hydrophobic modifier can make the surface of the modified metal powder have suitable hydrophobicity, so it is not easy to agglomerate and clump. Thus, in the conductive slurry, the modified metal powder can be uniformly dispersed, thereby making the conductive slurry have good fluidity and making the prepared electrode have a low volume resistivity.

[0049] As an example, the hydroxyl resin of the present invention may include at least one of polyvinyl acetal, phenolic resin, acrylic resin, modified acrylic resin, aldehyde-ketone resin and phenoxy resin; the curing agent may include at least one of isocyanate and amino resin; and the second solvent may include hydroxyl-free solvents such as butyl carbolic acid ester, ethyl carbolic acid ester, phthalate, tributyl acetylacetate, dipropylene glycol methyl ether, DBE (divalent ester), dimethyl succinate and so on.

[0050] Therefore, the hydroxyl groups on the surface of the modified metal powder and the hydroxyl resin in the conductive slurry can both react with the curing agent, thereby improving the strength of the prepared electrode and the adhesion between the electrode and the substrate.

[0051] In some embodiments of the present invention, based on the total mass of the metal conductive slurry, the mass percentage of the modified metal powder can be 88wt%-95wt%, such as 88wt%, 89wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, etc., preferably 91wt%-95wt%; the sum of the mass percentages of the hydroxyl resin and the curing agent can be 2wt%-8wt%, such as 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, etc. Since the surface polarity of the modified metal powder is effectively adjusted, the above-mentioned higher content of modified metal powder can still be uniformly dispersed in the conductive slurry. Thus, using the above-mentioned mass percentages of modified metal powder, hydroxyl resin and curing agent can make the prepared electrode body have a lower resistivity and better strength and adhesion.

[0052] Therefore, the electrode body prepared using the metal conductive paste provided by the present invention has a low volume resistivity, high strength, and good adhesion to the substrate.

[0053] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0054] Example 1

[0055] Step 1: Preparation of metal powder particles

[0056] (1) Preparation of metal ion solution: Weigh 1 mol of silver nitrate, add a certain amount of deionized water to prepare a silver nitrate solution with a silver ion content of 0.5 mol / L, then add 120 ml of ammonia water with a mass percentage concentration of 25 wt% to obtain a silver ammonia solution, heat to 40℃ and keep at a constant temperature for later use.

[0057] (2) Preparation of reducing agent solution: Weigh a hydrazine hydrate solution containing 2 mol of hydrazine hydrate, add a certain amount of deionized water to prepare a 0.50 mol / L solution, add 10 g of PEG400 solution with a mass percentage concentration of 10 wt%, stir evenly, and heat to 40℃ for later use.

[0058] (3) Add all the metal ion solution to the reducing agent solution. After reacting for 5 minutes, separate the silver particles produced. After multiple filtrations and water washings, until the water ion conductivity is less than 1 μs / cm, dry the washed silver powder at a temperature below 40°C.

[0059] Step 2: Preparation of modified metal powder

[0060] (1) Pour the dried silver powder into a high-speed mixer and stir and crush the metal powder at high speed with a linear velocity greater than 80 m / s.

[0061] (2) Under the condition of online speed less than 20m / s, the modifier composition solution (the specific composition and mass concentration of the amphiphilic modifier and hydrophobic modifier containing hydroxyl groups in the solution are shown in Table 1, and the solvent is methanol) is sprayed into the stirred and dispersed metal powder through a nozzle, and after continuous treatment for a certain period of time, it is further dried to obtain modified metal powder.

[0062] Step 3: Preparation of metal conductive paste

[0063] Modified metal powder, hydroxyl resin (hydroxyl value 8 mg KOH / g), curing agent (blocked isocyanate curing agent, NCO content 13.6%), and solvent (butyl carbolic acid ester and acetyl citrate ester 3:1) were mixed in a mass ratio of 91.5:3:0.16:5.34. The mixture was mechanically mixed using a planetary vacuum degassing device and then dispersed and ground using a three-roll mill to obtain a conductive metal slurry.

[0064] The preparation methods of steps 1 and 3 in Examples 2-4 and Comparative Examples 1-4 are the same as those in Example 1. The differences in step 2 are shown in Tables 1 and 2.

[0065] Testing of the properties of conductive metal pastes:

[0066] Metal conductive paste was printed onto the surface of a ceramic or silicon substrate using a 480-mesh screen, dried at 150℃-200℃ for 5 minutes, and then cured at 200℃-240℃ for 30 minutes (the curing temperature and time can be adjusted according to the different properties of hydroxyl resins and curing agents to achieve optimal conductivity and adhesion). The prepared electrode was 1 mm wide, 100 mm long, and 5 μm-15 μm thick. The resistance between the two ends of the electrode was measured, and the volume resistivity was calculated.

[0067] In addition, electrodes with a width of 30 mm and a length of 30 mm were prepared. The adhesion of the coating was tested using a pull-off method with an adhesive force tester. The specific operation process was as follows: the adhesive base (test column diameter 20 mm) was attached to the electrode surface with adhesive. The instrument was operated to detach the electrode from the substrate. The maximum pull force value of the electrode layer was recorded. This value was divided by the area of ​​the adhesive base to obtain the adhesion value of the sample.

[0068] The conductive pastes prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to performance testing using the above method. The test data are shown in Tables 1 and 2.

[0069] Table 1

[0070]

[0071]

[0072] Table 2

[0073]

[0074]

[0075] As can be seen from the test data in Tables 1 and 2, in Examples 1-4, by applying a modifier composition solution to the metal powder, the conductive slurry prepared in Examples 1-4 has a lower viscosity, better fluidity, and better fineness, indicating that the modified metal powder has less agglomeration and better dispersion in the conductive slurry. In addition, by modifying the metal powder, the electrode body finally prepared in Examples 1-4 has a lower resistivity and better adhesion, effectively improving its overall performance.

[0076] In Examples 1-4, the modified metal powders had relatively small particle sizes and fine powder textures, indicating that the modification effectively reduced the agglomeration of the metal powders. In Comparative Example 4, only an amphiphilic modifier containing hydroxyl groups was added, resulting in significant agglomeration of the metal powders. This indicates that adding only an amphiphilic modifier containing hydroxyl groups would make the metal powders more prone to agglomeration, while the addition of a hydrophobic modifier in Examples 1-4 effectively reduced the agglomeration of the metal powders.

[0077] The adhesion data in Comparative Examples 1-4 show that modifying metal powder with a hydroxyl-containing amphiphilic modifier can effectively improve the adhesion between the electrode and the substrate.

[0078] The terms "first" and "second" used in this document are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature marked "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing modified metal powder, characterized in that, Includes the following steps: (1) Mix the amphiphilic modifier containing hydroxyl groups and the hydrophobic modifier with the first solvent to obtain a modifier composition solution; (2) While stirring, the modifier composition solution is applied to the surface of the metal powder to obtain the modified metal powder; The hydroxyl-containing amphiphilic modifier molecule structure includes a hydrophobic group and at least two hydroxyl groups; The hydroxyl-containing amphiphilic modifier includes at least one of modified castor oil polyol, polyglycerol ester, Poloxamer 188, and polyethylene glycol-15-hydroxystearate.

2. The method according to claim 1, characterized in that, The mass ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier is 1:(4-19).

3. The method according to claim 1, characterized in that, The hydrophobic modifier includes C6-C 22 Saturated fatty acids, C6-C 22 Unsaturated fatty acids, C6-C 22 Fatty acid glycerides, C6-C 22 fatty amines and C6-C 22 At least one of the fatty amides.

4. The method according to claim 1, characterized in that, The boiling point of the first solvent is not greater than 100℃; The first solvent includes at least one of propanol, ethanol, methanol, and ethyl acetate.

5. The method according to claim 1, characterized in that, In step (2), the total mass ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier in the modifier composition solution to the mass ratio of the metal powder is (1-20):1000; The mass concentration of the modifier composition solution is 1wt%-5wt%; The volume average particle size Dv50 of the metal powder is 0.1μm-5μm; The metal powder includes at least one of silver powder, copper powder, and silver-coated copper powder.

6. The method according to claim 5, characterized in that, The total mass ratio of the hydroxyl-containing amphiphilic modifier and the hydrophobic modifier in the modifier composition solution to the mass ratio of the metal powder is (2-5):1000.

7. A modified metal powder, characterized in that, Prepared by the method according to any one of claims 1-6.

8. A metallic conductive paste, characterized in that, It includes modified metal powder, hydroxyl resin, curing agent and second solvent, wherein the modified metal powder is the modified metal powder as described in claim 7.

9. The metal conductive paste according to claim 8, characterized in that, Based on the total mass of the metal conductive paste, the mass percentage of the modified metal powder is 88wt%-95wt%, and the sum of the mass percentages of the hydroxyl resin and the curing agent is 2wt%-8wt%.

10. The metal conductive paste according to claim 8 or 9, characterized in that, The hydroxyl resin includes at least one of polyvinyl acetal, phenolic resin, acrylic resin, modified acrylic resin, aldehyde-ketone resin, and phenoxy resin; The curing agent includes at least one of isocyanate and amino resin.

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