Acrylic acid pressure-sensitive adhesive, acrylic acid chemical-resistant adhesive tape and preparation method and application thereof

Abstract

The invention discloses an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant adhesive tape as well as a preparation method and application of the acrylic pressure-sensitive adhesive and the acrylic chemical-resistant adhesive tape. The acrylic pressure-sensitive adhesive is prepared from the following components: a main monomer, a functional monomer, a cross-linking agent, a nano reinforcing agent, tackifying resin and a solvent, the main monomer comprises butyl acrylate, 2-ethylhexyl acrylate, acrylic acid and hydroxyethyl acrylate, and the functional monomer comprises dodecafluoroheptyl methacrylate. The acrylic acid chemical-resistant adhesive tape comprises a base material and an acrylic acid pressure-sensitive adhesive layer formed on the surface of the base material, has high initial stripping force and excellent alcohol solvent resistance and oleic acid resistance, can still keep stable performance in a small-area application scene, and meets the long-term bonding requirement in the field of electronic product assembly.

Description

Technical Field

[0001] This invention belongs to the field of acrylic tape technology, specifically relating to an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation methods and applications. Background Technology

[0002] In the assembly of electronic products, such as fixing laptop keyboard keys and bonding internal components of electronic watches, pressure-sensitive tape is often used to position and bond components. These applications place specific requirements on the chemical resistance of the tape. On the one hand, electronic products may come into contact with alcohol solvents such as isopropanol during production, cleaning, and use; on the other hand, oleic acid in human sweat may act on the adhesive bonding areas over a long period, leading to a decrease in the tape's adhesive performance or even its failure.

[0003] However, traditional pressure-sensitive adhesive tapes widely used in existing technologies have significant shortcomings in terms of resistance to alcohol solvents and oleic acid. Specifically, the molecular structure and degree of cross-linking of traditional pressure-sensitive adhesives make it difficult to form an effective chemical barrier. Alcohol solvents can easily penetrate into the adhesive layer, damaging the interfacial bonding between the adhesive layer and the substrate. At the same time, oleic acid, as a polar oil, will swell with the non-polar components in traditional pressure-sensitive adhesives, leading to a decrease in the cohesive strength of the adhesive layer. More importantly, in small-area, narrow-width applications such as the edges of laptop keyboard keys and micro-components in electronic watches, the bonding area of ​​the tape is already limited. The aforementioned problems of insufficient chemical resistance will be further amplified, making it easy for tape to fall off and components to loosen, seriously affecting the production yield and lifespan of electronic products.

[0004] To address these issues, the industry has attempted to improve performance by increasing the crosslinking density of traditional pressure-sensitive adhesives or adding solvent-resistant additives, but the results have been unsatisfactory. While increasing the crosslinking density can inhibit solvent penetration to some extent, it leads to a significant decrease in the tape's initial peel strength, failing to meet the demands for rapid positioning and reliable adhesion during assembly. Furthermore, the added solvent-resistant additives are mostly small molecules that are prone to migration during long-term use, causing their chemical resistance to degrade over time and making it difficult to achieve long-term stable adhesion. Therefore, developing a pressure-sensitive adhesive tape that combines high initial peel strength, excellent resistance to alcohol solvents and oleic acid, and maintains stable performance even in small-area applications has become a pressing technical challenge in the current electronics assembly field. Summary of the Invention

[0005] The main objective of this invention is to provide an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation methods and applications, in order to overcome the technical defects of traditional pressure-sensitive adhesive tapes in the prior art, such as poor resistance to alcohol solvents and oleic acid, and difficulty in guaranteeing performance in small-area application scenarios.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: The first aspect of the present invention provides an acrylic pressure-sensitive adhesive prepared from the following components: a main monomer, a functional monomer, an initiator, a crosslinking agent, a nano-reinforcing agent, a tackifying resin, and a solvent, wherein the main monomer includes butyl acrylate, isooctyl acrylate, acrylic acid, and hydroxyethyl acrylate, and the functional monomer includes dodecafluoroheptyl methacrylate.

[0007] Furthermore, the acrylic pressure-sensitive adhesive is prepared from the following components calculated by weight: 80-90 parts of main monomer, 2-5 parts of functional monomer, 0.5-1 part of initiator, 1-3 parts of crosslinking agent, 0.5-2 parts of nano-reinforcing agent, 3-8 parts of tackifying resin, and 30-50 parts of solvent.

[0008] A second aspect of the present invention provides a method for preparing the acrylic pressure-sensitive adhesive, comprising: Under the action of an initiator, the main monomer and functional monomer undergo a prepolymerization reaction to form a prepolymer; The nano-reinforcing agent is uniformly dispersed with the prepolymer, and a tackifying resin is added for composite modification. Then, a crosslinking agent is added for crosslinking and curing, and finally, a solvent is added to obtain an acrylic pressure-sensitive adhesive.

[0009] A third aspect of the present invention provides a method for preparing an acrylic chemical-resistant tape, comprising: applying the acrylic pressure-sensitive adhesive to the surface of a substrate, drying, and curing to obtain an acrylic chemical-resistant tape.

[0010] A fourth aspect of the present invention provides an acrylic chemical-resistant tape prepared by the method of preparing the acrylic chemical-resistant tape, comprising: a substrate, and an acrylic pressure-sensitive adhesive layer formed on the surface of the substrate.

[0011] A fifth aspect of the invention provides the application of the acrylic pressure-sensitive adhesive or the acrylic chemical-resistant tape in the field of electronic product assembly.

[0012] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The acrylic chemical-resistant tape of the present invention has excellent chemical resistance. Through the design of "fluorine-silicone-epoxy" triple solvent resistance barrier, the tape's resistance to alcohol solvents such as isopropanol and oleic acid is greatly improved. After 72 hours of oleic acid / isopropanol resistance test, the adhesive performance retention rate is >10%, which is far superior to the traditional pressure-sensitive adhesive system tape (usually retention rate <5%).

[0013] (2) The acrylic chemical-resistant tape of the present invention has high initial peel strength. Through the synergistic effect of dynamic cross-linking network and nano-reinforcement system, the tape has high initial peel strength, which can meet the needs of rapid positioning and reliable bonding in the assembly process of electronic products.

[0014] (3) The acrylic chemical-resistant tape of the present invention has stable performance in small areas. The nanofiber reinforcement system improves the cohesive strength of the adhesive layer. Even in small-area (e.g., width 1~3mm) bonding scenarios, it can still effectively resist solvent erosion and external force, and avoid bonding failure. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a physical image of an acrylic chemical-resistant tape according to a typical embodiment of the present invention. Detailed Implementation

[0017] In view of the problems existing in the prior art, the inventors of this invention have conducted extensive and in-depth research and have provided an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation methods and applications. The main achievement is to optimize the monomer composition, crosslinking system and reinforcement structure of the adhesive layer to achieve high performance indicators such as initial peel force >20N and oleic acid / isopropanol resistance 72-hour performance retention rate >10%. Moreover, it can maintain stable performance in small-area application scenarios, meeting the long-term bonding requirements in harsh environments such as electronic products and automobiles.

[0018] The following will provide a further explanation of the technical solution, its implementation process, and its principles.

[0019] The first aspect of the present invention provides an acrylic pressure-sensitive adhesive prepared from the following components: a main monomer, a functional monomer, an initiator, a crosslinking agent, a nano-reinforcing agent, a tackifying resin, and a solvent, wherein the main monomer includes butyl acrylate, isooctyl acrylate, acrylic acid, and hydroxyethyl acrylate, and the functional monomer includes dodecafluoroheptyl methacrylate.

[0020] In some embodiments, the acrylic pressure-sensitive adhesive is prepared from the following components calculated by weight: 80-90 parts of main monomer, 0.5-1 part of initiator, 2-5 parts of functional monomer, 1-3 parts of crosslinking agent, 0.5-2 parts of nano-reinforcing agent, 3-8 parts of tackifying resin, and 30-50 parts of solvent.

[0021] Furthermore, the main monomer comprises 40-50 parts of butyl acrylate, 30-40 parts of isooctyl acrylate, 5-8 parts of acrylic acid, and 3-5 parts of hydroxyethyl acrylate.

[0022] In this invention, the functional monomers include, but are not limited to, dodecafluoroheptyl methacrylate. A specific ratio of the main monomer to the functional monomer forms the basis for the "fluorine-silicone-epoxy" solvent-resistant barrier, wherein the introduction of dodecafluoroheptyl methacrylate can significantly reduce the surface energy of the adhesive layer and hinder solvent penetration.

[0023] Furthermore, the initiator includes, but is not limited to, azobisisobutyronitrile.

[0024] Furthermore, the crosslinking agent includes, but is not limited to, isocyanate crosslinking agents.

[0025] Furthermore, the crosslinking agent includes, but is not limited to, HDI trimer.

[0026] Furthermore, the nano-reinforcing agent includes nano-silica, silicon carbide nanofibers, and clay.

[0027] Furthermore, the nano-reinforcing agent comprises 0.3 to 1.2 parts of nano-silica, 0.1 to 0.5 parts of silicon carbide nanofibers, 0.1 to 0.3 parts of clay, and a silane coupling agent that may be added or not added selectively.

[0028] Furthermore, the nano-reinforcing agent comprises 0.3-1.2 parts of nano-silica, 0.1-0.5 parts of silicon carbide nanofibers, 0.1-0.3 parts of clay, and 0.3-0.8 parts of silane coupling agent. The synergistic use of silicon carbide nanofibers and clay allows the former to form a three-dimensional support and enhance mechanical strength, while the latter extends the solvent penetration path through its layered structure. Together, they inhibit cohesive failure of the adhesive layer, particularly ensuring performance in small-area applications.

[0029] Furthermore, the silane coupling agent includes, but is not limited to, KH-560. The isocyanate crosslinking agent reacts with the hydroxyl and carboxyl groups in the adhesive layer to form chemical crosslinks, while nano-silica forms physical crosslinking points through hydrogen bonds. This, in conjunction with the silane coupling agent (such as KH-560), constructs a siloxane crosslinking network, achieving a dual "chemical-physical" crosslinking that balances swelling resistance and high peel strength.

[0030] Furthermore, the tackifying resin includes, but is not limited to, terpene phenolic resin. The addition of terpene phenolic resin can enhance the adhesion of the adhesive layer to polar substrates (such as metal and plastic parts in electronic products), and it has excellent compatibility with acrylic systems without affecting chemical resistance.

[0031] Furthermore, the solvent is a mixture of ethyl acetate and toluene, wherein the mass ratio of ethyl acetate to toluene is 50~70:30~50.

[0032] A second aspect of the present invention provides a method for preparing the acrylic pressure-sensitive adhesive, comprising: Under the action of an initiator, the main monomer and functional monomer undergo a prepolymerization reaction to form a prepolymer; The nano-reinforcing agent is uniformly dispersed with the prepolymer, and a tackifying resin is added for composite modification. Then, a crosslinking agent is added for crosslinking and curing, and finally, a solvent is added to obtain an acrylic pressure-sensitive adhesive.

[0033] In some embodiments, the preparation method of the acrylic pressure-sensitive adhesive specifically includes: mixing the main monomer, functional monomer and initiator evenly, and performing a prepolymerization reaction at 60~70°C for 2~3 hours under the action of the initiator to form the prepolymer.

[0034] Furthermore, the amount of the initiator added is 0.5 to 1% of the total mass of the main monomer and the functional monomer.

[0035] Furthermore, the initiator includes azobisisobutyronitrile.

[0036] In some embodiments, the preparation method of the acrylic pressure-sensitive adhesive specifically includes: adding the nano-reinforcing agent to the prepolymer, dispersing it at a high speed of 2000-3000 r / min for 30-60 min, then adding the tackifying resin, heating to 75-85℃ for the composite modification for 1-2 h until the tackifying resin is completely dissolved, then cooling to 40-50℃, adding the crosslinking agent, mixing for 30-45 min, and finally adding the solvent to adjust the viscosity to 1500-2500 mPa. s, to obtain the acrylic pressure-sensitive adhesive.

[0037] A third aspect of the present invention provides a method for preparing an acrylic chemical-resistant tape, comprising: applying the acrylic pressure-sensitive adhesive to the surface of a substrate, drying, and curing to obtain an acrylic chemical-resistant tape.

[0038] In some embodiments, the preparation method of the acrylic chemical-resistant tape specifically includes: uniformly coating the acrylic pressure-sensitive adhesive onto the surface of the substrate, drying it at 100~130℃ for 3~5 min, and then curing it at 120~140℃ for 1~2 h to obtain the acrylic chemical-resistant tape.

[0039] This invention employs synergistic control of process parameters. Precise control of the prepolymerization reaction temperature (60~70℃) and time (2~3 h), the dispersion speed (2000~3000 r / min) and time (30~60 min) of the nano-reinforcing agent, and the curing temperature (120~140℃) and time (1~2 h) of the acrylic pressure-sensitive adhesive during the preparation process are key to ensuring the crosslinking density of the acrylic chemical-resistant tape layer, the uniformity of nanoparticle dispersion, and thus achieving the performance indicators.

[0040] A fourth aspect of the present invention provides an acrylic chemical-resistant tape prepared by the method of preparing the acrylic chemical-resistant tape, comprising: a substrate, and an acrylic pressure-sensitive adhesive layer formed on the surface of the substrate.

[0041] In some embodiments, the substrate includes, but is not limited to, PET film.

[0042] In some embodiments, the thickness of the substrate is 25-50 μm, and the thickness of the acrylic pressure-sensitive adhesive layer is 10-30 μm.

[0043] In some embodiments, the acrylic chemical-resistant tape has an initial peel force > 20N and a 72-hour performance retention rate of > 10% for oleic acid / isopropanol resistance.

[0044] In this invention, the acrylic chemical-resistant tape features the following three key innovative designs: (1) "Fluorine-Silicone-Epoxy" Triple Solvent Resistance Barrier Fluorine-containing groups are introduced by using the functional monomer dodecafluoroheptyl methacrylate. These fluorine-containing groups have extremely low surface energy and can form a dense hydrophobic and oleophobic layer on the surface of the adhesive layer, hindering the penetration of alcohol solvents and oleic acid. At the same time, a silane coupling agent (such as KH-560, used in conjunction with nano-silica) is added to the nano-reinforcing agent. The siloxane groups of the silane coupling agent can undergo a condensation reaction with the hydroxyl groups in the adhesive layer (from hydroxyethyl acrylate) to form a chemically bonded siloxane crosslinking network, further enhancing the solvent penetration resistance of the adhesive layer. In addition, the urea bonds and ester bonds formed by the reaction of the isocyanate crosslinking agent with the carboxyl groups in acrylic acid and the hydroxyl groups in hydroxyethyl acrylate can form synergistic crosslinks with trace amounts of epoxy groups in the system (from the silane coupling agent or resin), constructing a "fluorine-silicon-epoxy" triple barrier, which significantly reduces the swelling and penetration of solvents into the adhesive layer.

[0045] (2) Nanofiber reinforced system

[0046] Silicon carbide nanofibers and clay are used synergistically as nano-reinforcing agents. Silicon carbide nanofibers have high strength and high modulus, and can form a three-dimensional network support structure inside the adhesive layer, thereby improving the mechanical strength and cohesive strength of the adhesive layer. Clay has a layered silicate structure, which can be uniformly dispersed in the adhesive layer after organic modification. Its layered structure can extend the penetration path of the solvent, and at the same time, it forms a complementary reinforcement effect with silicon carbide nanofibers, effectively inhibiting cohesive failure caused by insufficient cohesive strength during the peeling process of the tape, and ensuring the bonding reliability in small-area application scenarios.

[0047] (3) Dynamic cross-linking network

[0048] A dual crosslinking system is formed by using isocyanate crosslinking agents (such as HDI trimer) and epoxy resin (or components containing epoxy groups): On the one hand, the polyisocyanate groups of HDI trimer can react rapidly with the hydroxyl and carboxyl groups in the adhesive layer to form a high density of chemical crosslinking points, ensuring the initial peel strength and cohesive strength of the adhesive layer; on the other hand, the oxazolidinone structure formed by the reaction of epoxy resin and isocyanate has a certain degree of dynamic reversibility. When subjected to solvent action or external impact, some dynamic crosslinking bonds can dissociate and recombine, which can both alleviate the swelling stress of the adhesive layer caused by the solvent and prevent the adhesive layer from becoming brittle due to excessive crosslinking, thereby balancing the requirements of high initial peel strength and swelling resistance.

[0049] Therefore, this invention uses a specific ratio of acrylate monomer compound system in the adhesive layer, combined with multiple crosslinking and reinforcement design, so that the acrylic chemical-resistant tape has high initial peel strength, excellent resistance to alcohol solvents and oleic acid, and can still maintain stable performance in small-area application scenarios.

[0050] A fifth aspect of the invention provides the application of the acrylic pressure-sensitive adhesive or the acrylic chemical-resistant tape in the field of electronic product assembly.

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0052] For experiments not specifically described in the examples, the procedures or conditions can be performed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available. Other unmentioned raw materials and instruments are all conventionally chosen and do not involve the core technical means of this invention.

[0053] Example 1 This embodiment provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and a method for preparing the same: (1) Raw material ratio (by mass parts) Main monomers: 45 parts butyl acrylate, 35 parts isooctyl acrylate, 6 parts acrylic acid, and 4 parts hydroxyethyl acrylate; Functional monomer: 3 parts of dodecafluoroheptyl methacrylate; Crosslinking agent: 2 parts HDI trimer; Nano-reinforcing agent: 0.8 parts nano-silica, 0.3 parts silicon carbide nanofibers, 0.2 parts clay (with 0.5 parts silane coupling agent KH-560 added); Tackifying resin: 5 parts of terpene phenolic resin; Solvents: 25 parts ethyl acetate, 25 parts toluene; Initiator: 0.8 parts of azobisisobutyronitrile.

[0054] (2) Preparation process

[0055] S1. Prepolymerization reaction: The main monomer, functional monomer and initiator are added to the reactor and stirred at 65°C for 2.5 hours to obtain the prepolymer; S2. Composite modification: Add nano-reinforcing agent and silane coupling agent to the prepolymer, disperse at high speed of 2500r / min for 45 minutes, then add terpene phenolic resin, and stir at 80℃ for 1.5 hours. S3. Crosslinking and curing: Cool to 45℃, add HDI trimer and stir for 40 minutes, then add solvent to adjust the viscosity to 2000 mPa. s, to obtain the adhesive solution; S4. Coating and molding: The adhesive is coated onto a 30μm thick PET substrate, with a coating thickness of 20μm. It is dried at 90℃ for 4 minutes and cured at 130℃ for 1.5 hours to obtain an acrylic chemical-resistant tape.

[0056] The actual image of the acrylic chemical-resistant tape prepared in Example 1 is shown below. Figure 1 As shown.

[0057] (3) Performance testing

[0058] Initial peel force: 23.5 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 12.3% (immersion conditions: 25℃, complete immersion in isopropanol). Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 11.8% (immersion conditions: 25℃, complete immersion in oleic acid). Small area peel force (width 2mm): 18.7N, no cohesive failure.

[0059] Example 2 This embodiment provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and a method for preparing the same: (1) Raw material ratio (by mass parts) Main monomers: 40 parts butyl acrylate, 40 parts isooctyl acrylate, 5 parts acrylic acid, and 3 parts hydroxyethyl acrylate; Functional monomer: 2 parts of dodecafluoroheptyl methacrylate; Crosslinking agent: 1.5 parts HDI trimer; Nano-reinforcing agent: 0.5 parts nano-silica, 0.2 parts silicon carbide nanofibers, 0.1 parts clay (with 0.3 parts silane coupling agent KH-560 added); Tackifying resin: 3 parts terpene phenolic resin; Solvents: 20 parts ethyl acetate, 20 parts toluene; Initiator: 0.6 parts of azobisisobutyronitrile.

[0060] (2) Preparation process

[0061] S1. Prepolymerization reaction: The main monomer, functional monomer and initiator are added to the reactor and stirred at 60°C for 3 hours to obtain the prepolymer; S2. Composite modification: Add nano-reinforcing agent and silane coupling agent to the prepolymer, disperse at high speed of 2000r / min for 60 minutes, then add terpene phenolic resin and stir at 75℃ for 2 hours. S3. Crosslinking and curing: Cool to 40℃, add HDI trimer and stir for 30 minutes, then add solvent to adjust the viscosity to 1500 mPa. s, to obtain the adhesive solution; S4. Coating and molding: The adhesive is coated onto a 25μm thick PET substrate, with a coating thickness of 15μm. It is then dried at 80℃ for 5 minutes and cured at 120℃ for 2 hours to obtain an acrylic chemical-resistant tape.

[0062] (3) Performance testing

[0063] Initial peel force: 20.8N (GB / T2792-2014); Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 10.5%; Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 10.2%; Small area peel force (1mm width): 16.3N, no cohesive failure.

[0064] Example 3 This embodiment provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and a method for preparing the same, which differs from Embodiment 1 in that: (1) Raw material ratio (by mass parts) Main monomers: 48 parts butyl acrylate, 32 parts isooctyl acrylate, 7 parts acrylic acid, and 3 parts hydroxyethyl acrylate; Functional monomer: 4 parts of dodecafluoroheptyl methacrylate; Crosslinking agent: 2.5 parts HDI trimer; Nano-reinforcing agent: 0.5 parts nano-silica, 0.4 parts silicon carbide nanofibers, 0.25 parts clay (with 0.6 parts silane coupling agent KH-560 added); Tackifying resin: 6 parts of terpene phenolic resin; Solvents: 20 parts ethyl acetate, 20 parts toluene; Initiator: 0.7 parts of azobisisobutyronitrile.

[0065] (2) Preparation process

[0066] The preparation process is the same as in Example 1.

[0067] (3) Performance testing

[0068] Initial peel force: 24.2 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 13.1%; Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 12.6%; Small area peel force (3mm width): 19.5N, no cohesive failure.

[0069] Example 4 This embodiment provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and a method for preparing the same, which differs from Embodiment 1 in that: (1) Raw material ratio (by mass parts) Main monomers: 46 parts butyl acrylate, 34 parts isooctyl acrylate, 6 parts acrylic acid, and 4 parts hydroxyethyl acrylate; Functional monomer: 3.5 parts of dodecafluoroheptyl methacrylate; Crosslinking agent: 2.2 parts HDI trimer; Nano-reinforcing agent: 0.9 parts nano-silica, 0.3 parts silicon carbide nanofibers, 0.2 parts clay (with 0.6 parts silane coupling agent KH-560 added); Tackifying resin: 5.5 parts of terpene phenolic resin; Solvents: 25 parts ethyl acetate, 25 parts toluene; Initiator: 0.85 parts of azobisisobutyronitrile.

[0070] (2) Preparation process

[0071] The preparation process is the same as in Example 1.

[0072] (3) Performance testing

[0073] Initial peel force: 25.1 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 13.5% (immersion conditions: 25℃, complete immersion in isopropanol).

[0074] Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 12.9% (immersion conditions: 25℃, complete immersion in oleic acid). Small area peel force (width 2.5mm): 19.2N, no cohesive failure.

[0075] Example 5 This embodiment provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and a method for preparing the same, which differs from Embodiment 1 in that: (1) Raw material ratio (by mass parts) Main monomers: 50 parts butyl acrylate, 30 parts isooctyl acrylate, 5 parts acrylic acid, and 5 parts hydroxyethyl acrylate; Functional monomer: 5 parts of dodecafluoroheptyl methacrylate; Crosslinking agent: 3 parts HDI trimer; Nano-reinforcing agent: 0.9 parts nano-silica, 0.5 parts silicon carbide nanofibers, 0.3 parts clay (with 0.3 parts silane coupling agent KH-560 added); Tackifying resin: 8 parts of terpene phenolic resin; Solvents: 15 parts ethyl acetate, 15 parts toluene; Initiator: 0.5 parts of azobisisobutyronitrile.

[0076] (2) Preparation process

[0077] The preparation process is the same as in Example 1.

[0078] (3) Performance testing

[0079] Initial peel force: 24.6 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 12.3%; Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 14.1%; Small area peel force (width 2.5mm): 20.1N, no cohesive failure.

[0080] Comparative Example 1 The tape is prepared using a conventional terpolymer pressure-sensitive adhesive of butyl acrylate, ethyl acrylate and vinyl acetate, with the addition of a conventional isocyanate crosslinking agent (1 part). The substrate is placed in a coating machine, coated with a pressure-sensitive adhesive layer, cured in an oven at 100-120℃, cooled, and then laminated with a release film. The tape is then slit and rolled up to obtain the finished product.

[0081] The performance test results are as follows: Initial peel force: 18.2 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 4.8%; Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 3.5%; Small area peel force (width 2mm): 12.5N, obvious cohesive failure occurs.

[0082] Comparative Example 2 This comparative example provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation method. The difference between this example and Example 1 is that the functional monomer dodecafluoroheptyl methacrylate is not added; otherwise, they are the same as in Example 1.

[0083] The performance test results are as follows: Initial peel force: 21.3 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 6.2%; Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 5.8%.

[0084] Small area peel force (width 2mm): 14.8N, slight cohesive failure occurs.

[0085] Comparative Example 3 This comparative example provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation method. The difference between this example and Example 1 is that silicon carbide nanofibers are not added to the nano-reinforcing agent; otherwise, they are the same as in Example 1.

[0086] The performance test results are as follows: Initial peel force: 22.1 N; Isopropanol resistance: After 72 hours of immersion, peel strength retention rate is 8.3%. Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 7.9%. Small area peel force (width 2mm): 15.2N, slight cohesive failure occurs.

[0087] Comparative Example 4 This comparative example provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation method. The difference between this example and Example 1 is that no silane coupling agent KH-560 was added; otherwise, they are the same as in Example 1.

[0088] The performance test results are as follows: Initial peel force: 21.8 N; Isopropanol resistance: After 72 hours of immersion, peel strength retention rate is 7.5%. Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 7.1%; Small area peel force (width 2mm): 14.9N, slight cohesive failure occurs.

[0089] Comparative Example 5 This comparative example provides an acrylic pressure-sensitive adhesive, an acrylic chemical-resistant tape, and their preparation method. The difference from Example 1 is that the crosslinking agent is a common isocyanate (TDI dimer) instead of HDI trimer, while the rest is the same as in Example 1.

[0090] Performance test results: Initial peel force: 19.7 N; Isopropanol resistance: After 72 hours of immersion, the peel strength retention rate is 6.8%; Oleic acid resistance: After 72 hours of immersion, the peel strength retention rate is 6.3%; Small area peel force (width 2mm): 13.6N, no cohesive failure.

[0091] As can be seen from the above examples and comparative examples, the acrylic chemical-resistant tape of the present invention is significantly superior to traditional pressure-sensitive adhesive tapes in terms of initial peel strength, resistance to alcohol solvents, resistance to oleic acid, and small-area bonding reliability, and can fully meet the stringent bonding requirements of electronic products and automobiles.

[0092] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0093] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0094] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. An acrylic pressure-sensitive adhesive, characterized in that, It is prepared from the following components: main monomer, functional monomer, initiator, crosslinking agent, nano-reinforcing agent, tackifying resin and solvent, wherein the main monomer includes butyl acrylate, isooctyl acrylate, acrylic acid and hydroxyethyl acrylate, and the functional monomer includes dodecafluoroheptyl methacrylate.

2. The acrylic pressure-sensitive adhesive according to claim 1, characterized in that, It is prepared from the following components calculated by weight: 80-90 parts of main monomer, 2-5 parts of functional monomer, 0.5-1 part of initiator, 1-3 parts of crosslinking agent, 0.5-2 parts of nano-reinforcing agent, 3-8 parts of tackifying resin and 30-50 parts of solvent.

3. The acrylic pressure-sensitive adhesive according to claim 1 or 2, characterized in that: The main monomers include 40-50 parts of butyl acrylate, 30-40 parts of isooctyl acrylate, 5-8 parts of acrylic acid, and 3-5 parts of hydroxyethyl acrylate; And / or, the initiator includes azobisisobutyronitrile; And / or, the crosslinking agent includes isocyanate crosslinking agents, preferably HDI trimers; And / or, the nano-reinforcing agent includes nano-silica, silicon carbide nanofibers, and clay; Preferably, the nano-reinforcing agent comprises 0.3-1.2 parts of nano-silica, 0.1-0.5 parts of silicon carbide nanofibers, 0.1-0.3 parts of clay, and a silane coupling agent that may or may not be added. Particularly preferred, the nano-reinforcing agent comprises 0.3-1.2 parts of nano-silica, 0.1-0.5 parts of silicon carbide nanofibers, 0.1-0.3 parts of clay, and 0.3-0.8 parts of silane coupling agent; Particularly preferred, the silane coupling agent comprises KH~560; And / or, the tackifying resin includes terpene phenolic resin; And / or, the solvent is a mixture of ethyl acetate and toluene, wherein the mass ratio of ethyl acetate to toluene is 50~70:30~50.

4. The method for preparing the acrylic pressure-sensitive adhesive according to any one of claims 1-3, characterized in that, include: Under the action of an initiator, the main monomer and functional monomer undergo a prepolymerization reaction to form a prepolymer; The nano-reinforcing agent is uniformly dispersed with the prepolymer, and a tackifying resin is added for composite modification. Then, a crosslinking agent is added for crosslinking and curing, and finally, a solvent is added to obtain an acrylic pressure-sensitive adhesive.

5. The method for preparing acrylic pressure-sensitive adhesive according to claim 4, characterized in that, Specifically, it includes: The main monomer, functional monomer and initiator are mixed evenly, and a prepolymerization reaction is carried out at 60~70℃ for 2~3 hours under the action of the initiator to form the prepolymer; Preferably, the amount of the initiator added is 0.5-1% of the total mass of the main monomer and the functional monomer; Preferably, the initiator comprises azobisisobutyronitrile.

6. The method for preparing acrylic pressure-sensitive adhesive according to claim 4, characterized in that, Specifically, it includes: The nano-reinforcing agent is added to the prepolymer and dispersed at a high speed of 2000-3000 r / min for 30-60 min. Then, the tackifying resin is added, and the mixture is heated to 75-85℃ for composite modification for 1-2 h until the tackifying resin is completely dissolved. After that, the temperature is lowered to 40-50℃, the crosslinking agent is added, and the mixture is stirred for 30-45 min. Finally, the solvent is added to adjust the viscosity to 1500-2500 mPa. s, to obtain the acrylic pressure-sensitive adhesive.

7. A method for preparing an acrylic chemical-resistant adhesive tape, characterized in that, include: The acrylic pressure-sensitive adhesive according to any one of claims 1-3 is applied to the surface of a substrate, dried, and cured to obtain an acrylic chemical-resistant tape.

8. The method for preparing acrylic chemical-resistant tape according to claim 7, characterized in that, Specifically, it includes: The acrylic pressure-sensitive adhesive is uniformly coated onto the surface of the substrate, dried at 80-100°C for 3-5 minutes, and then cured at 120-140°C for 1-2 hours to obtain the acrylic chemical-resistant tape.

9. The acrylic chemical-resistant tape prepared by the method of any one of claims 7-8, characterized in that, include: The substrate, and the acrylic pressure-sensitive adhesive layer formed on the surface of the substrate; Preferably, the substrate comprises a PET film; Preferably, the thickness of the substrate is 25~50μm, and the thickness of the acrylic pressure-sensitive adhesive layer is 10~30μm; Preferably, the acrylic chemical-resistant tape has an initial peel force > 20N and a 72-hour performance retention rate of > 10% for oleic acid / isopropanol resistance.

10. The application of the acrylic pressure-sensitive adhesive according to any one of claims 1 to 3 or the acrylic chemical-resistant tape according to claim 9 in the field of electronic product assembly.

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