Composite current collector adhesive and method of making same, composite current collector

Abstract

The application belongs to the technical field of acrylic glue, and particularly relates to a glue for composite current collector, a preparation method thereof and a composite current collector, which comprises the following steps: S1, dissolving tetra-n-butylammonium tetraphenylborate in deionized water to obtain a modified solution; S2, adding hollow silica particles to the modified solution, controlling the reaction temperature to be 70-75 DEG C, stirring and reacting for 1-1.5 h to obtain pre-modified particles; S3, filtering and removing the unreacted reaction residues on the surface of the pre-modified particles, cleaning with deionized water, and drying at 90-95 DEG C to obtain modified particles; and S4, adding the modified particles to acrylic glue, stirring for 0.5-1 h to obtain the glue for composite current collector. According to the application, the tetra-n-butylammonium tetraphenylborate is combined with the hydroxyl groups on the surface of the hollow silica particles to form an organic-inorganic hybrid interface, the benzene ring and the borate group in the molecular structure of the tetra-n-butylammonium tetraphenylborate can provide thermal stability, and the high-temperature resistance of the glue system can be improved by the synergistic effect of the thermal resistance of the silica itself.

Description

Technical Field

[0001] This invention belongs to the field of acrylic adhesive technology, specifically relating to an adhesive for composite current collectors and its preparation method, and the composite current collector. Background Technology

[0002] In modern industrial manufacturing, the bonding of polymer materials to metal materials is one of the key processes in many fields. In the field of composite current collectors, due to the significant differences in the surface chemical properties and physical characteristics of polymer materials and metal materials, existing adhesives are mostly improved to enhance their bonding strength.

[0003] In practical applications, the adhesive needs to remain stable during hot pressing (70–150°C) and curing (80–150°C). Insufficient thermal stability of the adhesive may cause the composite layer to deform or its adhesion to decrease at high temperatures, affecting the yield rate.

[0004] Therefore, how to provide an adhesive for composite current collectors that overcomes insufficient thermal stability is a technical problem that urgently needs to be solved in this field.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0006] This disclosure provides at least one adhesive for composite current collectors, a method for preparing the same, and a composite current collector.

[0007] In a first aspect, embodiments of this disclosure provide a method for preparing a composite current collector adhesive, comprising the following steps: Step S1, dissolving tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a modified solution; Step S2, adding hollow silica particles to the modified solution, controlling the reaction temperature at 70-75°C, and stirring the reaction to obtain pre-modified particles; Step S3, filtering to remove unreacted reaction residues on the surface of the pre-modified particles, washing with deionized water, and drying to obtain modified particles; Step S4, adding the modified particles to acrylic adhesive and stirring to obtain a composite current collector adhesive.

[0008] In one optional embodiment, the concentration of ammonium tetra-n-butyltetraphenylborate in the modified solution in step S1 is 10-40%.

[0009] In one optional embodiment, the hollow silica particles have a particle size range of 200-300 nm.

[0010] In one optional embodiment, the mass ratio of hollow silica particles, tetrabutyltetraphenylborate ammonium and deionized water in step S2 is 20:(10-40):100.

[0011] In one optional embodiment, the mass ratio of modified particles to acrylic adhesive in step S4 is 2.2 to 4.6:100.

[0012] In one optional embodiment, the stirring in step S4 specifically includes: sequentially performing low-speed stirring and dispersion at 200 rpm for 10-30 min, ultrasonic dispersion for 10-15 min, and ultrahomogeneous dispersion for 10-15 min.

[0013] Secondly, embodiments of this disclosure also provide a composite current collector adhesive prepared by the method described above, comprising 100 parts by mass of acrylic adhesive and 2.2-4.6 parts by mass of modified particles.

[0014] In one optional embodiment, the distribution width of the modified particles in the composite current collector adhesive is 1.2-2.5.

[0015] Thirdly, embodiments of this disclosure also provide a composite current collector, comprising: a PP substrate and a copper foil; wherein the PP substrate and the copper foil are bonded together using the adhesive for composite current collectors as described above.

[0016] In one optional embodiment, the composite current collector has a peel force of not less than 6 N / cm at 150°C.

[0017] The beneficial effects of this invention are that the adhesive for the composite current collector and its preparation method, and the composite current collector form an organic-inorganic hybrid interface by combining tetra-n-butyltetraphenylborate ammonium with the hydroxyl groups on the surface of hollow silica particles. The benzene ring and boric acid groups in its molecular structure can provide thermal stability, and the synergistic effect with the heat resistance of silica itself can improve the high temperature resistance of the adhesive system. In addition, the organic part of tetra-n-butyltetraphenylborate ammonium can form hydrogen bonds with the polar groups in acrylic resin, enhance the interfacial bonding force with the matrix, and achieve the high temperature resistance of the composite current collector.

[0018] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0022] In this document, as used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0023] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0024] The following describes some embodiments of the present invention in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] This disclosure provides a method for preparing a composite current collector adhesive, comprising the following steps: Step S1, dissolving tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a modified solution; Step S2, adding hollow silica particles to the modified solution, controlling the reaction temperature at 70-75℃, stirring for 1-1.5h to obtain pre-modified particles; Step S3, filtering to remove unreacted reaction residues on the surface of the pre-modified particles, washing with deionized water, and drying at 90-95℃ to obtain modified particles; Step S4, adding the modified particles to acrylic adhesive, stirring for 0.5-1h to obtain the composite current collector adhesive.

[0026] In some embodiments, specifically, the concentration of ammonium tetra-n-butyltetraphenylborate in the modified solution in step S1 is 10-40%.

[0027] In some embodiments, specifically, the particle size range of the hollow silica particles is 200-300 nm.

[0028] Specifically, hollow silica spherical particles (HSP) possess extremely high specific surface area and good chemical stability. After modification, their surface is rich in hydroxyl groups, enabling them to form hydrogen bonds or other types of physicochemical bonds with polymer substrates and metal surfaces. This bonding not only strengthens the physical adhesion between the metal and the polymer substrate but also enhances the overall adhesive strength through chemical bonding.

[0029] Specifically, the addition of hollow silica spherical particles (HSP) can improve the tensile strength and toughness of the adhesive. The nanoparticles have good dispersibility and can be evenly distributed in the adhesive, forming reinforcing points. This gives the adhesive higher resistance to fracture under stress and better disperses external stress, preventing localized damage.

[0030] Specifically, hollow silica spherical particles (HSP), as a chemically inert filler, can improve the adhesive's resistance to harsh environments, including high temperatures, humidity, and corrosive chemicals. Due to their excellent stability, silica particles can protect the adhesive and maintain its bonding performance for a long time in high-temperature or corrosive environments, extending its service life.

[0031] In some embodiments, specifically, the mass ratio of hollow silica particles, tetrabutyltetraphenylborate ammonium and deionized water in step S2 is 20:(10-40):100.

[0032] In some embodiments, specifically, the mass ratio of modified particles to acrylic adhesive in step S4 is 2.2 to 4.6:100.

[0033] In some embodiments, specifically, the stirring in step S4 includes: sequentially performing low-speed stirring and dispersion at 200 rpm for 10-30 min, ultrasonic dispersion for 10-15 min, and ultrahomogeneous dispersion for 10-15 min.

[0034] This disclosure also provides a composite current collector adhesive prepared by the method described above, comprising 100 parts by weight of acrylic adhesive and 2.2-4.6 parts by weight of modified particles.

[0035] This disclosure also provides a composite current collector, comprising: a PP substrate and a copper foil; wherein the PP substrate and the copper foil are bonded together using the adhesive for composite current collectors as described above.

[0036] Example 1

[0037] Step S1, Solution preparation: Dissolve the modified substance tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a 20% concentration solution;

[0038] Step S2, Particle addition and reaction: Add 20 g of hollow silica particles (200 nm) to 100 g of modified solution, control the temperature at 70 °C, and stir for 1.5 hours.

[0039] Step S3, Post-processing: After the reaction is complete, the unreacted modified material is removed by filtration, the particles are washed with deionized water, and finally dried at 95°C to obtain the modified particles.

[0040] Step S4: Add 2 grams of modified granules to 100 grams of acrylic glue and stir at 200 rpm for 30 minutes.

[0041] Step S5, Adhesion test: Apply adhesive to the PP substrate with a thickness of 10μm, dry it, and then laminate it with copper foil. Test the 180° peel force at 150℃.

[0042] Specifically, the test results of Example 1 are shown in Table 1 below.

[0043] Table 1

[0044] serial number Additives Glue peel strength (N / cm) 1 No silica added 2.5 2 / 2.6 3 Tetra-n-butyltetraphenylborate ammonium 4.2 4 KH570 3.0 5 KH560 3.2

[0045] Specifically, the HSP particles modified with tetra-n-butyltetraphenylborate significantly improved the adhesion of the adhesive, increasing the adhesion by 68% compared to untreated HSP particles. This indicates that the surface modification of tetra-n-butyltetraphenylborate effectively improved the bonding force between HSP particles and the adhesive substrate.

[0046] Example 2

[0047] Step S1, Solution preparation: Dissolve the modified substance tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a 20% concentration solution;

[0048] Step S2, Particle addition and reaction: Add 20 g of hollow silica particles (200 nm) to 100 g of modified solution, control the temperature at 70 °C, and stir for 1.5 hours.

[0049] Step S3, Post-processing: After the reaction is complete, the unreacted modified material is removed by filtration, the particles are washed with deionized water, and finally dried at 95°C to obtain the modified particles.

[0050] Step S4: Add 2 grams of modified particles to 100 grams of acrylic glue and stir to disperse;

[0051] Step S5, Adhesion test: Apply adhesive to the PP substrate with a thickness of 10μm, dry it, and then laminate it with copper foil. Test the 180° peel force at 150℃.

[0052] In particular, step S4, stirring and dispersing, is carried out using three methods:

[0053] Method 1: Perform initial dispersion at a stirring speed of 200 rpm for 30 minutes.

[0054] Method 2: Initially disperse the mixture at a stirring speed of 200 rpm for 15 minutes, then sonicate it for 15 minutes.

[0055] Method 3: Initially disperse at 200 rpm for 10 minutes, then sonicate for 10 minutes, and finally ultrahomogenize for 10 minutes.

[0056] Specifically, the test results of Example 2 are shown in Table 2 below.

[0057] Table 2

[0058]

[0059] Specifically, the average particle size of HSP particles in single-stage dispersion was 450 nm, indicating that the particles were relatively large and the dispersion effect was poor. Two-stage dispersion reduced the average particle size to 270 nm, showing some improvement, but significant size differences still remained. Multi-stage dispersion further reduced the average particle size to 210 nm, and significantly improved particle size uniformity, resulting in a significant increase in adhesive peel strength from 4.2 to 7.1.

[0060] Specifically, compared to single-stage and two-stage dispersion methods, multi-stage dispersion technology can more effectively reduce the average particle size of HSP particles and significantly reduce the particle distribution width (SPAN), thereby ensuring uniform distribution of particles in the matrix and improving adhesive peel strength.

[0061] Example 3

[0062] Step S1, Solution preparation: Dissolve the modified substance tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a 20% concentration solution;

[0063] Step S2, Particle addition and reaction: Add 20 grams of silica particles to 100 grams of modified solution, control the temperature at 70℃, and stir for 1.5 hours.

[0064] Step S3, Post-processing: After the reaction is complete, the unreacted modified material is removed by filtration, the particles are washed with deionized water, and finally dried at 95°C to obtain the modified particles.

[0065] Step S4: Add 2 grams of modified particles to 100 grams of acrylic glue and stir to disperse;

[0066] Step S5, Adhesion test: Apply adhesive to the PP substrate with a thickness of 10μm, dry it, and then laminate it with copper foil. Test the 180° peel force at 150℃.

[0067] In step S2, hollow silica and solid silica particles of different sizes are selected for comparison.

[0068] Specifically, the test results of Example 3 are shown in Table 3 below.

[0069] Table 3

[0070]

[0071] Specifically, tests showed that hollow silica particles with a diameter in the 200-300 nm range exhibited the best adhesion and dispersibility. Smaller particles (<200 nm), while providing a larger specific surface area, tend to aggregate due to their higher surface energy, resulting in poor dispersibility. They also readily interact with the adhesive, reducing the adhesive's wetting effect on the substrate and decreasing peel strength. Larger particles (>300 nm), due to their larger size, partially isolate the substrate, leading to a decrease in peel strength. Solid silica, due to its high density, tends to settle, resulting in poor dispersion and a decrease in peel strength.

[0072] Therefore, this embodiment specifies that the optimal particle size range for hollow silica particles is 200-300 nm.

[0073] Example 4

[0074] Step S1, Solution preparation: Dissolve the modified substance tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a solution with a concentration of X%.

[0075] Step S2, 200-300nm particle addition and reaction: Add 20g of silica particles to 100g of modified solution, control the temperature at 70℃, and stir for 1.5 hours.

[0076] Step S3, Post-processing: After the reaction is complete, the unreacted modified material is removed by filtration, the particles are washed with deionized water, and finally dried at 95°C to obtain the modified particles.

[0077] Step S4: Add 2 grams of modified particles to 100 grams of acrylic glue and stir to disperse;

[0078] Step S5, Adhesion test: Apply adhesive to the PP substrate with a thickness of 10μm, dry it, and then laminate it with copper foil. Test the 180° peel force at 150℃.

[0079] Specifically, the test results of Example 4 are shown in Table 4 below.

[0080] Table 4

[0081] serial number X Peel force (N / cm) 1 0 2.1 2 5 3.5 3 10 6.6 4 20 7.1 5 30 6.9 6 40 6.2

[0082] Specifically, when X=20, the adhesive peel strength is optimal. As the value increases further, because tetrabutyltetraphenylborate is a small molecule, excessive tetrabutyltetraphenylborate will penetrate between the polymer chains of the adhesive molecules, affecting the bonding force between the adhesive molecules, thus reducing the peel strength.

[0083] Example 5

[0084] Step S1, Solution preparation: Dissolve the modified substance tetra-n-butyltetraphenylborate ammonium in deionized water to prepare a 20% concentration solution;

[0085] Step S2, Particle addition and reaction: Add 20 grams of silica particles to 100 grams of modified solution, control the temperature at 70℃, and stir for 1.5 hours.

[0086] Step S3, Post-processing: After the reaction is complete, the unreacted modified material is removed by filtration, the particles are washed with deionized water, and finally dried at 95°C to obtain the modified particles.

[0087] Step S4: Add the modified particles to 100g of acrylic glue and stir to disperse;

[0088] Step S5, Adhesion test: Apply adhesive to the PP substrate with a thickness of 10μm, dry it, and then laminate it with copper foil. Test the 180° peel force at 150℃.

[0089] After determining the optimal particle size range as 200-300 nm, the amount of modified particles added in step S4 was adjusted and compared.

[0090] Specifically, the test results of Example 5 are shown in Table 5 below.

[0091] Table 5

[0092] serial number HSP dosage (%) Adhesion (N / cm) 1 1 6.2 2 2.2 7.3 3 3.4 9.1 4 4.6 8.5 5 5.8 6.8

[0093] Specifically, according to experimental data, the adhesive performance is optimal when the HSP particle content is 3.4%, with the best peel strength (9.1 N / cm). When the HSP particle content is 5.8%, the performance drops significantly, indicating that excessive particles lead to a decrease in the adhesive's peel strength.

[0094] In summary, this composite current collector adhesive and its preparation method, and the composite current collector form an organic-inorganic hybrid interface by bonding tetra-n-butyltetraphenylborate ammonium with the hydroxyl groups on the surface of hollow silica particles. The benzene rings and borate groups in its molecular structure provide thermal stability, and the synergistic effect with the heat resistance of silica itself can improve the high-temperature resistance of the adhesive system. In addition, the organic part of tetra-n-butyltetraphenylborate ammonium can form hydrogen bonds with the polar groups in acrylic resin, enhancing the interfacial bonding force with the matrix, thus achieving the high-temperature resistance of the composite current collector.

[0095] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a composite current collector adhesive, characterized in that, Includes the following steps: Step S1: Dissolve ammonium tetra-n-butyltetraphenylborate in deionized water to prepare a modified solution; Step S2: Add hollow silica particles to the modification solution, control the reaction temperature at 70-75℃, and stir the reaction to obtain pre-modified particles; Step S3: Filter to remove unreacted reaction residues on the surface of the pre-modified particles, wash with deionized water and dry to obtain modified particles; Step S4: Add the modified particles to the acrylic adhesive and stir to obtain the adhesive for composite current collectors; The stirring in step S4 specifically includes: sequentially performing low-speed stirring and dispersion at 200 rpm for 10-30 min, ultrasonic dispersion for 10-15 min, and ultra-homogeneous dispersion for 10-15 min. The concentration of ammonium tetrabutyltetraphenylborate in the modified solution in step S1 is 10-40%; The hollow silica particles have a particle size range of 200-300 nm. In step S4, the mass ratio of modified particles to acrylic adhesive is 2.2–4.6:

100.

2. The preparation method according to claim 1, characterized in that, The mass ratio of hollow silica particles, tetrabutyltetraphenylborate ammonium, and deionized water in step S2 is 20:(10-40):

100.

3. A composite current collector adhesive prepared by the method described in any one of claims 1 or 2, characterized in that, It comprises 100 parts acrylic adhesive and 2.2-4.6 parts modified granules by weight.

4. The adhesive for composite current collectors as described in claim 3, characterized in that, The distribution width of the modified particles in the adhesive for the composite current collector is 1.2-2.

5.

5. A composite current collector, characterized in that, include: PP substrate and copper foil; The PP substrate and the copper foil are bonded together using the adhesive for composite current collectors as described in claim 3.

6. The composite current collector as described in claim 5, characterized in that, The composite current collector has a peel force of not less than 6 N / cm at 150°C.

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