Conductive acrylic pressure sensitive adhesive and method for preparing the same

Abstract

The application discloses a conductive acrylic pressure-sensitive adhesive and a preparation method thereof; graphene is modified by a silane coupling agent KH-560 (gamma-glycidoxypropyltrimethoxysilane), so that the crosslinking degree of the pressure-sensitive adhesive is increased, the compactness is enhanced, and the wetting property, the bonding strength and the water resistance of the pressure-sensitive adhesive are improved. The application loads nano cuprous oxide on modified graphene to prepare nano composite particles, effectively improves the problem of uneven dispersion of the nano cuprous oxide in the polymer, and enhances the conductivity of the pressure-sensitive adhesive. By adding 2-acrylamido-2-methylpropanesulfonic acid ammonium salt as an emulsifier and beta-carboxyethyl acrylate as an internal crosslinking agent, and by controlling the mass ratio among the nano composite particles, the 2-acrylamido-2-methylpropanesulfonic acid ammonium salt and the beta-carboxyethyl acrylate, the water resistance and the initial tack of the pressure-sensitive adhesive are improved.

Description

Technical Field

[0001] This invention relates to the field of conductive acrylic pressure-sensitive adhesive technology, specifically to a conductive acrylic pressure-sensitive adhesive and its preparation method. Background Technology

[0002] With the rapid development of industries such as electronics, the demand for pressure-sensitive adhesives with conductive properties is becoming increasingly urgent. Pressure-sensitive adhesives need to have good conductivity, adhesion, and water resistance to meet the needs of industrial production.

[0003] Graphene is considered a rising star in industries such as electronics, and its unique electrical conductivity has led to its widespread use as a filler in polymer nanocomposites. However, a major challenge in preparing high-performance graphene / polymer nanocomposites is the tendency of graphene sheets to aggregate. Strong π-π packing and van der Waals interactions make graphene dispersion in polymers extremely difficult. Most methods involve modifying graphene, but these modifications often result in decreased conductivity. Therefore, nanocomposite particles can be prepared by loading metal ions to improve conductivity.

[0004] Because the conductive network inside the pressure-sensitive adhesive cannot be formed when the content of nanocomposite particles is low, it is necessary to increase the amount of nanocomposite particles added to reach the "permeation threshold" of nanocomposite particles, so that the conductive network inside the pressure-sensitive adhesive can be formed and the conductivity of the pressure-sensitive adhesive can be improved. However, this brings problems. The addition of a large number of nanocomposite particles will cause a small amount to migrate to the surface of the pressure-sensitive adhesive, which will reduce the contact area between the pressure-sensitive adhesive and the substrate, resulting in a decrease in the initial tack of the pressure-sensitive adhesive, a reduction in the peristalsis between chains, and a decrease in the 180° peel force of the pressure-sensitive adhesive.

[0005] Therefore, inventing a conductive acrylic pressure-sensitive adhesive is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide a conductive acrylic pressure-sensitive adhesive and its preparation method to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A method for preparing a conductive acrylic pressure-sensitive adhesive, characterized in that:

[0009] S1: Add nanocomposite particles to butyl acrylate and disperse by ultrasonication to obtain composite butyl acrylate; mix composite butyl acrylate, 2-ethylhexyl acrylate and methyl methacrylate evenly and add to aqueous solution to obtain composite acrylic acid aqueous solution; add 2-acrylamido-2-methylpropanesulfonate ammonium salt to aqueous solution to obtain emulsifier aqueous solution;

[0010] S2: Add the composite acrylic acid aqueous solution and the emulsifier aqueous solution dropwise into the reaction vessel, add half of the sodium persulfate solution, and heat and stir once; add dodecyl mercaptan and β-carboxyethyl acrylate, add the other half of the sodium persulfate solution, heat and stir a second time, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0011] Furthermore, in the conductive acrylic pressure-sensitive adhesive, the mass ratio of nanocomposite particles: 2-acrylamido-2-methylpropanesulfonate ammonium salt: β-carboxyethyl acrylate is (5-8): 2: 8.

[0012] Furthermore, the nanocomposite particles in step S1 are prepared according to the following method:

[0013] Graphene was added to an ethanol solution of silane coupling agent, stirred, centrifuged, and dried to obtain modified graphene. The modified graphene was ultrasonically dispersed in deionized water, anhydrous copper sulfate and sodium dodecyl sulfate were added, and the mixture was ultrasonically treated. Ascorbic acid, sodium hydroxide and acrylic acid were added, and the mixture was centrifuged and vacuum dried to obtain nanocomposite particles.

[0014] Furthermore, in the modified graphene, the mass ratio of graphene to silane coupling agent is 1:1; in the nanocomposite particles, the mass ratio of modified graphene to anhydrous copper sulfate is 3.75:1; the vacuum drying temperature is 65-70℃, and the vacuum drying time is 12h.

[0015] The silane coupling agent is γ-glycidoxypropyltrimethoxysilane.

[0016] Furthermore, in step S1, the mass ratio of composite butyl acrylate: 2-ethylhexyl acrylate: methyl methacrylate is 1:1:1;

[0017] The aqueous solution is an aqueous solution of a mixture of sodium dodecyl sulfate and sodium bicarbonate.

[0018] Furthermore, in the conductive acrylic pressure-sensitive adhesive, the mass ratio of composite acrylic aqueous solution: emulsifier aqueous solution: sodium persulfate solution is 1:0.25:0.02;

[0019] The concentration of the composite acrylic acid aqueous solution is 0.15 g / mL, the concentration of the emulsifier aqueous solution is 0.09 g / mL, and the concentration of the sodium persulfate aqueous solution is 0.07 g / mL.

[0020] Furthermore, in step S2, the first heating and stirring temperature is 80-83℃, and the heating and stirring time is 1-2 hours; the second heating and stirring temperature is 85-90℃, and the heating and stirring time is 3-5 hours.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention modifies graphene with silane coupling agent KH-560 (γ-glycidyl etheroxypropyltrimethoxysilane). During the curing process of acrylate emulsion, the siloxane carried on the graphene surface can form a hydrophobic Si-O-Si structure on the side chain of the acrylic polymer, which reduces the surface free energy of the pressure-sensitive adhesive and improves the bonding strength and water resistance of the pressure-sensitive adhesive.

[0022] This invention prepares nanocomposite particles by loading nano-cuprous oxide onto modified graphene, effectively improving the problem of uneven dispersion of nano-cuprous oxide in polymers. During the polymerization of nanocomposite particles with acrylic monomers, the degree of crosslinking of the pressure-sensitive adhesive is improved, the intermolecular forces of the polymer are enhanced, the cohesive strength is increased, and the inter-linking site spacing is reduced, thus improving the tack of the pressure-sensitive adhesive. The hydrophilic functional groups on the surface of the nanocomposite particles improve the wettability of the pressure-sensitive adhesive and enhance its 180° peel strength. Due to the large amount of nano-cuprous oxide loaded on the surface of the modified graphene, the problem of decreased conductivity caused by the modification of the graphene surface is improved, significantly increasing the conductivity of the modified graphene, promoting the formation of conductive networks, and enhancing the conductivity of the pressure-sensitive adhesive.

[0023] This invention solves the problem of uneven dispersion in composite acrylic acid caused by excessive addition of nanocomposite particles by adding ammonium 2-acrylamido-2-methylpropanesulfonate as an emulsifier. At the same time, the steric hindrance of the geminal dimethyl group in the molecule makes the polymer chain formed have strong water resistance, thus enhancing the water resistance of the pressure-sensitive adhesive. When the ammonium sulfonate group dries, the ammonia volatilizes to form sulfonic acid groups with weak hydrophilicity, which further enhances the water resistance of the pressure-sensitive adhesive.

[0024] This invention solves the problem of decreased initial tack and peel strength of pressure-sensitive adhesives caused by excessive addition of nanocomposite particles by adding β-carboxyethyl acrylate as an internal crosslinking agent. The addition of β-carboxyethyl acrylate utilizes its low glass transition temperature to improve the adhesion of the pressure-sensitive adhesive. At the same time, its longer side carboxylic acid chains can generate a denser and more effective contact and interaction between the polymer and the substrate, thereby enhancing the initial tack and peel strength of the pressure-sensitive adhesive.

[0025] This invention avoids the formation of gels due to excessive or insufficient addition of 2-acrylamido-2-methylpropanesulfonate ammonium salt, which reduces the water resistance and peel strength of the pressure-sensitive adhesive, by controlling the mass ratio between nanocomposite particles, ammonium 2-acrylamido-2-methylpropanesulfonate, and β-carboxyethyl acrylate; and avoids excessive addition of β-carboxyethyl acrylate, which leads to an increase in the particle size of the pressure-sensitive adhesive, excessive molecular structure strength, and gelation, resulting in a decrease in the adhesive force and peel strength of the pressure-sensitive adhesive. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0027] Example 1

[0028] S1: Add 5g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 2g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0029] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 80℃, and stir for 2h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 85℃, stir for 5h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0030] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0031] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0032] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to make a dry film about 25μm thick. The film was then immersed in tap water at room temperature. After the film was detached, the time was recorded. See Table 3.

[0033] Example 2

[0034] S1: Add 6g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 2g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0035] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 83℃, and stir for 1h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 90℃, stir for 3h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0036] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0037] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0038] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to make a dry film about 25μm thick. The film was then immersed in tap water at room temperature. After the film was detached, the time was recorded. See Table 3.

[0039] Example 3

[0040] S1: Add 7g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 2g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0041] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 80℃, and stir for 2h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 85℃, stir for 5h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0042] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0043] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0044] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to make a dry film about 25μm thick. The film was then immersed in tap water at room temperature. After the film was detached, the time was recorded. See Table 3.

[0045] Example 4

[0046] S1: Add 8g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 2g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0047] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 83℃, and stir for 1h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 90℃, stir for 3h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0048] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0049] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0050] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to form a dry film with a thickness of about 25μm. The film was then immersed in tap water at room temperature, and the peel strength retention rate of the pressure-sensitive adhesive was recorded after 7 days. See Table 3.

[0051] Comparative Example 1 (insufficient amount of 2-acrylamido-2-methylpropanesulfonate ammonium salt added)

[0052] S1: Add 8g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and then add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 0.5g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0053] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 83℃, and stir for 1h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 90℃, stir for 3h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0054] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0055] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0056] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to form a dry film with a thickness of about 25μm. The film was then immersed in tap water at room temperature, and the peel strength retention rate of the pressure-sensitive adhesive was recorded after 7 days. See Table 3.

[0057] Comparative Example 2 (excessive amount of 2-acrylamido-2-methylpropanesulfonate ammonium salt added)

[0058] S1: Add 8g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 4g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0059] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 83℃, and stir for 1h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 90℃, stir for 3h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0060] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0061] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0062] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to form a dry film with a thickness of about 25μm. The film was then immersed in tap water at room temperature, and the peel strength retention rate of the pressure-sensitive adhesive was recorded after 7 days. See Table 3.

[0063] Comparative Example 3 (excessive amount of β-carboxyethyl acrylate added)

[0064] S1: Add 8g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 2g of 2-acrylamido-2-methylpropanesulfonate ammonium salt to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0065] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 83℃, and stir for 1h; add dodecyl mercaptan and 16g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 90℃, stir for 3h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0066] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0067] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0068] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to form a dry film with a thickness of about 25μm. The film was then immersed in tap water at room temperature, and the peel strength retention rate of the pressure-sensitive adhesive was recorded after 7 days. See Table 3.

[0069] Comparative Example 4 (Sodium alkyl diphenyl ether disulfonate as emulsifier)

[0070] S1: Add 8g of nanocomposite particles to 40g of butyl acrylate and ultrasonically disperse for 30min to obtain composite butyl acrylate; mix 20g of composite butyl acrylate, 20g of 2-ethylhexyl acrylate and 20g of methyl methacrylate evenly and then add to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain a composite acrylic acid aqueous solution; add 2g of disodium alkyl diphenyl ether disulfonate to an aqueous solution of sodium dodecyl sulfate and sodium bicarbonate to obtain an emulsifier aqueous solution;

[0071] S2: Add 50g of composite acrylic acid aqueous solution and 12.5g of emulsifier aqueous solution to a reaction vessel, add 0.5g of sodium persulfate solution, heat to 83℃, and stir for 1h; add dodecyl mercaptan and 8g of β-carboxyethyl acrylate, add 0.5g of sodium persulfate solution, heat to 90℃, stir for 3h, and cool to obtain conductive acrylic pressure-sensitive adhesive.

[0072] Tests: Initial tack, holding tack and 180° peel strength: Tested according to GB / T 4852-2022, GB / T 4851-1998 and GB / T 2792-2014 standards, see Table 1;

[0073] Conductivity test: The conductivity was measured using the four-point probe method, as shown in Table 2;

[0074] Water resistance test: The pressure-sensitive adhesive was coated on a 5cm×5cm glass plate to form a dry film with a thickness of about 25μm. The film was then immersed in tap water at room temperature, and the peel strength retention rate of the pressure-sensitive adhesive was recorded after 7 days. See Table 3.

[0075] Table 1 Adhesive performance of pressure-sensitive adhesive

[0076] Initial tack / ball size Tackiness / h Peel strength (N / 25mm) Example 1 7.4 130 17.2 Example 2 8.1 152 17.6 Example 3 8.8 189 18.3 Example 4 9.5 222 19.0 Comparative Example 1 4.1 94 12.9 Comparative Example 2 4.3 93 13.1 Comparative Example 3 5.1 99 14.4 Comparative Example 4 5.5 102 15.3

[0077] Table 2 Conductive properties of pressure-sensitive adhesive

[0078] <![CDATA[Conductivity / (S·cm -1 )]]> Example 1 <![CDATA[1.1×10 -2 ]]> Example 2 <![CDATA[1.2×10 -2 ]]> Example 3 <![CDATA[1.4×10 -2 ]]> Example 4 <![CDATA[1.8×10 -2 ]]> Comparative Example 1 <![CDATA[5.4×10 -3 ]]> Comparative Example 2 <![CDATA[5.9×10 -3 ]]> Comparative Example 3 <![CDATA[6.3×10 -3 ]]> Comparative Example 4 <![CDATA[8.8×10 -3 ]]>

[0079] Table 3 Water resistance properties of pressure-sensitive adhesives

[0080] Peel strength retention rate / % Example 1 63 Example 2 66 Example 3 69 Example 4 72 Comparative Example 1 41 Comparative Example 2 37 Comparative Example 3 48 Comparative Example 4 50

[0081] Examples 1-4 show that when the mass ratio of nanocomposite particles: 2-acrylamido-2-methylpropanesulfonate ammonium salt: β-carboxyethyl acrylate is 8:2:8, the pressure-sensitive adhesive has the best bonding performance, conductivity and water resistance.

[0082] In Comparative Example 1, the insufficient addition of 2-acrylamido-2-methylpropanesulfonate ammonium salt resulted in insufficient emulsifier dosage during phase inversion. Furthermore, the insufficient emulsifier dosage during phase inversion, coupled with the competition between the added monomers and the original latex particles for emulsifier when forming polymers, caused instability in the system, making it prone to gel formation and leading to a decrease in the adhesive properties and water resistance of the pressure-sensitive adhesive.

[0083] In Comparative Example 2, the excessive addition of 2-acrylamido-2-methylpropanesulfonate ammonium salt led to the early formation of a copolymer by a large amount of 2-acrylamido-2-methylpropanesulfonate ammonium salt, resulting in a lack of emulsifier in the subsequent monomer polymerization process, causing system instability and a decrease in the adhesive performance and water resistance of the pressure-sensitive adhesive.

[0084] In Comparative Example 3, the excessive addition of β-carboxyethyl acrylate led to an increase in the particle size of the pressure-sensitive adhesive, resulting in excessive cross-linking of the molecular structure and gelation, which in turn reduced the adhesive performance of the pressure-sensitive adhesive.

[0085] In Comparative Example 4, disodium alkyl diphenyl ether disulfonate was used as an emulsifier to replace ammonium 2-acrylamido-2-methylpropanesulfonate. Because the disodium alkyl diphenyl ether disulfonate emulsifier is hydrophilic, its molecules migrate to the surface of the pressure-sensitive adhesive layer, resulting in a decrease in the water resistance and peel strength of the pressure-sensitive adhesive.

[0086] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a conductive acrylic pressure-sensitive adhesive, characterized in that: S1: Add nanocomposite particles to butyl acrylate and disperse by ultrasonication to obtain composite butyl acrylate; mix composite butyl acrylate, 2-ethylhexyl acrylate and methyl methacrylate evenly and add to aqueous solution to obtain composite acrylic acid aqueous solution; add 2-acrylamido-2-methylpropanesulfonate ammonium salt to aqueous solution to obtain emulsifier aqueous solution; S2: Add the composite acrylic acid aqueous solution and the emulsifier aqueous solution dropwise into the reaction vessel, add half of the sodium persulfate solution dropwise, and heat and stir once; add dodecyl mercaptan and β-carboxyethyl acrylate, add the other half of the sodium persulfate solution dropwise, heat and stir a second time, and cool to obtain conductive acrylic pressure-sensitive adhesive; In the conductive acrylic pressure-sensitive adhesive, the mass ratio of nanocomposite particles: 2-acrylamido-2-methylpropanesulfonate ammonium salt: β-carboxyethyl acrylate is (5-8): 2: 8; The nanocomposite particles in step S1 are prepared as follows: Graphene was added to an ethanol solution of a silane coupling agent, stirred, centrifuged, and dried to obtain modified graphene. The modified graphene was ultrasonically dispersed in deionized water, anhydrous copper sulfate and sodium dodecyl sulfate were added, and the mixture was ultrasonically treated. Ascorbic acid, sodium hydroxide and acrylic acid were added, and the mixture was centrifuged and vacuum dried to obtain nanocomposite particles. In the modified graphene, the mass ratio of graphene to silane coupling agent is 1:1; in the nanocomposite particles, the mass ratio of modified graphene to anhydrous copper sulfate is 3.75:1; the vacuum drying temperature is 65-70℃, and the vacuum drying time is 12h. The silane coupling agent is γ-glycidoxypropyltrimethoxysilane.

2. The method for preparing a conductive acrylic pressure-sensitive adhesive according to claim 1, characterized in that: In step S1, the mass ratio of butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate is 1:1:

1. The aqueous solution is an aqueous solution of a mixture of sodium dodecyl sulfate and sodium bicarbonate.

3. The method for preparing a conductive acrylic pressure-sensitive adhesive according to claim 1, characterized in that: In the conductive acrylic pressure-sensitive adhesive, the mass ratio of composite acrylic aqueous solution: emulsifier aqueous solution: sodium persulfate solution is 1:0.25:0.02; The concentration of the composite acrylic acid aqueous solution is 0.15 g / mL, the concentration of the emulsifier aqueous solution is 0.09 g / mL, and the concentration of the sodium persulfate aqueous solution is 0.07 g / mL.

4. The method for preparing a conductive acrylic pressure-sensitive adhesive according to claim 1, characterized in that: In step S2, the first heating and stirring temperature is 80-83℃, and the heating and stirring time is 1-2 hours; the second heating and stirring temperature is 85-90℃, and the heating and stirring time is 3-5 hours.

5. The conductive acrylic pressure-sensitive adhesive prepared by the method of any one of claims 1 to 4.