Post-curing high-strength acrylate pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses a post-curing high-strength acrylate pressure-sensitive adhesive and a preparation method thereof, and relates to a pressure-sensitive adhesive and a preparation method thereof. The invention aims to solve the problem of low bonding strength of the existing pressure-sensitive adhesive. The post-cured high-strength acrylate pressure-sensitive adhesive is prepared from the following components in parts by weight: 70 to 90 parts of a soft monomer, 5 to 15 parts of a hard monomer, 7 to 12 parts of a functional monomer A1, 5 to 10 parts of a functional monomer A2, 0.5 to 1.5 parts of an initiator, 80 to 120 parts of a solvent, 0.5 to 10 parts of a cross-linking agent, 10 to 30 parts of a reinforcing agent and 0.5 to 5 parts of a latent curing agent. Through matching of functional monomers and use of the reinforcing agent, the cross-linking agent and the latent curing agent, the post-curing high-strength acrylate pressure-sensitive adhesive with excellent comprehensive performance is prepared.

Description

Technical Field

[0001] The present invention relates to a pressure - sensitive adhesive and a preparation method thereof. Background Art

[0002] Acrylate pressure - sensitive adhesives have high adhesion strength to a variety of materials, and at the same time have excellent ultraviolet aging resistance, water resistance and storage stability, and are used in many fields. In the aviation industry, in order to meet the requirements of anti - corrosion, moisture - proof, protection, stealth and other aspects of aircraft, a large number of protective tapes or functional tapes are also used. Due to the aerodynamic challenges and frictional forces brought by high - speed flight on the surface of the aircraft during flight, higher requirements are put forward for the adhesion strength and heat resistance of the pressure - sensitive adhesive used in the adhesive functional layer. The pressure - sensitive adhesives used in ordinary tapes are easily peeled off or even fall off, endangering the flight safety of the aircraft.

[0003] Chinese Patent CN202410066974.3 prepared a reactive pressure - sensitive adhesive using an acrylate prepolymer, an epoxy resin, an imidazole curing agent and a photo - initiator. Although the state of the pressure - sensitive adhesive layer before curing was not mentioned in the patent, according to its description, the main body of the pressure - sensitive adhesive is an acrylate prepolymer with a monomer conversion rate not exceeding 20% and an epoxy resin. The mixture before curing lacks the cross - linking and forming step of the pressure - sensitive adhesive, so its state is closer to a highly viscous epoxy film rather than the form of a pressure - sensitive adhesive, and this system has a strong odor due to the presence of a large amount of unreacted monomers. Chinese Patent 202410609969.2 prepared a high - shear - strength thermosetting pressure - sensitive adhesive using raw materials such as SiC fillers, modified acrylate, styrene - butadiene rubber, epoxy resin, etc., but did not include the preparation and cross - linking process of the pressure - sensitive adhesive film, nor the investigation of the performance of the pressure - sensitive adhesive before thermal curing.

[0004] Although the above patents have all tried to improve the performance of the pressure - sensitive adhesive through thermosetting reactions, none of them have achieved the goal of presenting the form of a pressure - sensitive adhesive before curing and approaching the state of a semi - structural adhesive after curing. The present invention provides a post - curing high - strength acrylate pressure - sensitive adhesive and a preparation method thereof. The prepared pressure - sensitive adhesive exhibits good pressure - sensitive adhesive characteristics before post - curing, and can form a high adhesion strength after being heated and cured when pasted on a substrate. Summary of the Invention

[0005] The object of the present invention is to solve the problem of low adhesion strength of existing pressure - sensitive adhesives, and to provide a heat - curable high - strength acrylate pressure - sensitive adhesive and a preparation method thereof.

[0006] A post-curing high-strength acrylate pressure-sensitive adhesive is prepared from 70 to 90 parts by weight of soft monomer, 5 to 15 parts by weight of hard monomer, 7 to 12 parts by weight of functional monomer A1, 5 to 10 parts by weight of functional monomer A2, 0.5 to 1.5 parts by weight of initiator, 80 to 120 parts by weight of solvent, 0.5 to 10 parts by weight of crosslinking agent, 10 to 30 parts by weight of reinforcing agent, and 0.5 to 5 parts by weight of latent curing agent.

[0007] A preparation method of a post-curing high-strength acrylate pressure-sensitive adhesive is specifically completed according to the following steps:

[0008] I. Weigh 70 to 90 parts by weight of soft monomer, 5 to 15 parts by weight of hard monomer, 7 to 12 parts by weight of functional monomer A1, 5 to 10 parts by weight of functional monomer A2, 0.5 to 1.5 parts by weight of initiator, 80 to 120 parts by weight of solvent, 0.5 to 10 parts by weight of crosslinking agent, 10 to 30 parts by weight of reinforcing agent, and 0.5 to 5 parts by weight of latent curing agent according to parts by weight;

[0009] II. Add the soft monomer, hard monomer, functional monomer A1, a part of the initiator, and a part of the solvent weighed in step I into a reaction vessel, and react for 0.5 h to 1 h under stirring and at a temperature of 75 °C to 83 °C;

[0010] III. Mix the remaining initiator, the remaining solvent, and functional monomer A2, and drop the mixed material into the reaction vessel at a constant speed within the time range of 1 h to 1.5 h. After the dropping is completed, continue the reaction and stop when the viscosity increases to 2500 cp to 3000 cp to obtain a glue solution;

[0011] IV. Add a crosslinking agent, a reinforcing agent, and a latent curing agent to the glue solution obtained in step III, disperse evenly, coat the glue solution on a PET release film using a coater with a thickness of 100 - 600 microns, leave it to stand for 0.5 h to 2 h, then put it into an oven and dry it at a temperature of 50 °C to 60 °C for 1 h to 2 h to obtain a post-curing high-strength acrylate pressure-sensitive adhesive.

[0012] The principle of the present invention:

[0013] Based on conventional soft and hard monomers as basic raw materials, functional monomers A1 and A2 provide reactive groups. Through free radical polymerization reaction, an acrylate pressure-sensitive adhesive solution with certain strength, heat resistance, and reactivity is obtained; when making the film, a crosslinking agent is added to react with the reactive groups in the pressure-sensitive adhesive to complete crosslinking, realizing the forming and preparation of the pressure-sensitive adhesive, and endowing it with basic tack, holding power, and adhesive strength; while adding the crosslinking agent, a reinforcing agent and a latent curing agent are added. During the later heating process, the latent curing agent can react with the reactive groups in the pressure-sensitive adhesive molecules or in the reinforcing agent structure to achieve post-curing, further improving its adhesive strength, and finally obtaining a post-curing high-strength acrylate pressure-sensitive adhesive.

[0014] The advantages of the present invention compared with the prior art are as follows:

[0015] 1. The present invention combines the pressure-sensitive characteristics of pressure-sensitive adhesives with the high-strength characteristics of structural adhesives to prepare a pressure-sensitive adhesive with both properties. The synthetic acrylate polymer is used as the main body of the pressure-sensitive adhesive film to provide pressure-sensitive characteristics. The prepared pressure-sensitive adhesive has good initial tack and holding tack, can be pasted by gently pressing at room temperature, and has a high peel strength. During the film-forming process of the pressure-sensitive adhesive film, a reinforcing agent and a latent curing agent are added to endow the pressure-sensitive adhesive with the characteristics of post-curing. After heat curing, the adhesive film exhibits the characteristics of a structural adhesive, with high bonding strength and good heat resistance.

[0016] 2. The pressure-sensitive adhesive prepared by the present invention has excellent construction process performance. Due to its pressure-sensitivity, when the pressure-sensitive adhesive is applied to the construction site, only gentle pressure is required for good bonding to form a high bonding strength. In addition, the processability of the pressure-sensitive adhesive of the present invention is better than that of the non-pressure-sensitive structural adhesive. During the post-curing process, continuous external pressure is not required. By directly raising the temperature on the basis of the original paste, the post-curing of the pressure-sensitive adhesive can be realized, and a high structural bonding strength can be obtained. The construction is simple and the efficiency is high.

[0017] 3. The pressure-sensitive adhesive prepared by the present invention has a long storage period at room temperature. The latent curing agent used in the present invention is a microcapsule-type curing agent. The microcapsule wall physically isolates the curing agent from the reactive functional groups in the main system. Only when the temperature reaches a certain level will the microcapsule wall of the curing agent be damaged, and the curing agent encapsulated therein will play a curing role to complete the post-curing process. Therefore, the prepared pressure-sensitive adhesive film has a long storage period, and its performance can remain stable for a long time.

[0018] 4. The pressure-sensitive adhesive prepared by the present invention has excellent performance in all aspects. The initial tack of the pressure-sensitive adhesive is 8 - 15, the 180° peel strength is 1 - 1.6 kN / m, the holding tack at room temperature is > 24 h, and it has a good state and performance of the pressure-sensitive adhesive. After post-curing, the shear strength of the pressure-sensitive adhesive can reach 12 MPa - 16 MPa, which can meet the requirements of general structural bonding. The pressure-sensitive adhesive film can be stored at room temperature for more than one month and at -18°C for more than half a year. After being stored for half a year, the performance of the pressure-sensitive adhesive has not changed significantly. Specifically, the initial tack is 8 - 14, the 180° peel strength is 1 - 1.5 kN / m, the holding tack at room temperature is > 24 h, and the shear strength after curing can still reach 12 MPa - 15 MPa. Specific Embodiments

[0019] The following describes the specific embodiments of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0020] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or variations thereof such as "comprises" or "comprising" and the like will be understood to include the stated element or component and not to exclude other elements or other components.

[0021] The beneficial effects of the present invention are verified by the following embodiments. It should be understood that the preferred embodiments described herein are only for illustrating and explaining the present invention and are not intended to limit the present invention.

[0022] Specific Embodiment 1: A post-curing type high-strength acrylate pressure-sensitive adhesive in this embodiment is prepared from 70 to 90 parts by weight of soft monomer, 5 to 15 parts by weight of hard monomer, 7 to 12 parts by weight of functional monomer A1, 5 to 10 parts by weight of functional monomer A2, 0.5 to 1.5 parts by weight of initiator, 80 to 120 parts by weight of solvent, 0.5 to 10 parts by weight of crosslinking agent, 10 to 30 parts by weight of reinforcing agent, and 0.5 to 5 parts by weight of latent curing agent.

[0023] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the soft monomer is one or more of octadecyl acrylate, n-decyl methacrylate, butyl acrylate, isooctyl acrylate, ethyl acrylate, n-octyl acrylate, lauryl acrylate, tetradecyl acrylate, polyethylene glycol 400 diacrylate, and polypropylene glycol 400 diacrylate. Other steps are the same as those in Specific Embodiment 1.

[0024] Specific Embodiment 3: The difference between this embodiment and one of Specific Embodiments 1 or 2 is that the hard monomer is one or more of methyl methacrylate, vinyl acetate, ethyl methacrylate, isobutyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, tetrahydrofurfuryl methacrylate, styrene, and acrylonitrile. Other steps are the same as those in Specific Embodiment 1 or 2.

[0025] Specific Embodiment 4: The difference between this embodiment and one of Specific Embodiments 1 to 3 is that the functional monomer A1 is one or more of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, and 4-hydroxybutyl acrylate. Other steps are the same as those in Specific Embodiments 1 to 3.

[0026] Specific Embodiment 5: The difference between this embodiment and any one of Specific Embodiments 1 to 4 is that the functional monomer A2 is a carboxyl group-containing functional monomer or an epoxy group-containing functional monomer. Among them, the carboxyl group-containing functional monomers include acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, maleic acid, and 2-acryloyloxyethyl succinic acid; the epoxy group-containing functional monomers include glycidyl acrylate, glycidyl methacrylate, glycidyl acrylate ether, glycidyl methacrylate ether, allyl glycidyl ether, 1,2-epoxy-4-vinylcyclohexane, and 4-hydroxybutyl acrylate glycidyl ether. One or several of them can be used, and the carboxyl group-containing functional monomers are not used simultaneously with the epoxy group-containing monomers. Other steps are the same as those in Specific Embodiments 1 to 4.

[0027] Specific Embodiment 6: The difference between this embodiment and any one of Specific Embodiments 1 to 5 is that the initiator is one of benzoyl peroxide or azobisisobutyronitrile; the solvent is one or several of ethyl acetate, methyl ethyl ketone, toluene, and butyl acetate. Other steps are the same as those in Specific Embodiments 1 to 5.

[0028] Specific Embodiment 7: The difference between this embodiment and any one of Specific Embodiments 1 to 6 is that when the functional monomer A2 is one or several of glycidyl acrylate, glycidyl methacrylate, glycidyl acrylate ether, glycidyl methacrylate ether, allyl glycidyl ether, 1,2-epoxy-4-vinylcyclohexane, and 4-hydroxybutyl acrylate glycidyl ether, the crosslinking agent is one of toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate; when the functional monomer A2 is one of acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, maleic acid, and 2-acryloyloxyethyl succinic acid, the crosslinking agent is one of aziridine or acetylacetonate. Other steps are the same as those in Specific Embodiments 1 to 6.

[0029] Specific Embodiment 8: The difference between this embodiment and any one of Specific Embodiments 1 to 7 is that the reinforcing agent is one or several of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenolic epoxy resin, o-cresol novolac epoxy resin, brominated epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, and aliphatic epoxy resin. Other steps are the same as those in Specific Embodiments 1 to 7.

[0030] Specific Embodiment 9: The difference between this embodiment and any one of Specific Embodiments 1 to 8 is that the latent curing agent is the microencapsulated imidazole curing agent SC10208E purchased from Shanghai Suoke Purification Materials Co., Ltd. Other steps are the same as those in Specific Embodiments 1 to 8.

[0031] Embodiment 10: A preparation method of a post-curing high-strength acrylate pressure-sensitive adhesive is specifically completed according to the following steps:

[0032] 1. Weigh 70 to 90 parts by weight of soft monomers, 5 to 15 parts by weight of hard monomers, 7 to 12 parts by weight of functional monomer A1, 5 to 10 parts by weight of functional monomer A2, 0.5 to 1.5 parts by weight of initiator, 80 to 120 parts by weight of solvent, 0.5 to 10 parts by weight of crosslinking agent, 10 to 30 parts by weight of reinforcing agent, and 0.5 to 5 parts by weight of latent curing agent;

[0033] 2. Add the soft monomers, hard monomers, functional monomer A1, a part of the initiator, and a part of the solvent weighed in step 1 to a reaction vessel, and react for 0.5 h to 1 h under stirring at a temperature of 75 °C to 83 °C;

[0034] 3. Mix the remaining initiator, the remaining solvent, and functional monomer A2, and drop the mixed material into the reaction vessel at a constant speed within the time range of 1 h to 1.5 h. After the dropping is completed, continue the reaction and stop when the viscosity increases to 2500 cp to 3000 cp to obtain a glue solution;

[0035] 4. Add the crosslinking agent, reinforcing agent, and latent curing agent to the glue solution obtained in step 3, disperse evenly, coat the glue solution on a PET release film using a coater with a thickness of 100 - 600 microns, leave it to dry for 0.5 h to 2 h, and then put it into an oven and dry it at a temperature of 50 °C to 60 °C for 1 h to 2 h to obtain a post-curing high-strength acrylate pressure-sensitive adhesive.

[0036] The following examples are used to verify the beneficial effects of the present invention:

[0037] Example 1: A preparation method of a post-curing high-strength acrylate pressure-sensitive adhesive is completed according to the following steps:

[0038] 1. Weigh 40 g of isooctyl acrylate, 35 g of butyl acrylate, 15 g of methyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 9 g of methacrylic acid, 0.8 g of dibenzoyl peroxide, 50 g of ethyl acetate, 50 g of toluene, 2 g of aluminum acetylacetonate, 20 g of E44 epoxy resin, and 3 g of latent curing agent SC10208E;

[0039] 2. Add isooctyl acrylate, butyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, a part of dibenzoyl peroxide, a part of ethyl acetate, and a part of toluene to a reaction vessel, and react for 1 h under stirring at a temperature of 80 °C;

[0040] III. Mix the remaining benzoyl peroxide, the remaining ethyl acetate, the remaining toluene and methacrylic acid, and drop the mixed material into the reaction vessel at a constant rate within 1.5 h. After the dropping is completed, continue the reaction and stop when the viscosity increases to 2750 cp to obtain a glue solution;

[0041] IV. Add aluminum acetylacetonate, epoxy resin E44 and latent curing agent SC10208E to the glue solution obtained in step III, and disperse evenly at high speed; coat the glue solution on a PET release film using a 500-micron coater, leave it to dry for 0.5 h, and then put it into an oven and dry it at a temperature of 60 °C for 1 h to obtain a post-cured high-strength acrylate pressure-sensitive adhesive.

[0042] Example 2: A method for preparing a post-cured high-strength acrylate pressure-sensitive adhesive is completed according to the following steps:

[0043] I. Weigh 45 g of n-octyl acrylate, 25 g of butyl acrylate, 10 g of isobornyl methacrylate, 8 g of hydroxypropyl acrylate, 7 g of allyl glycidyl ether, 0.8 g of benzoyl peroxide, 80 g of ethyl acetate, 20 g of toluene, 0.8 g of toluene diisocyanate, 30 g of F51 epoxy resin, and 4 g of latent curing agent SC10208E;

[0044] II. Add n-octyl acrylate, butyl acrylate, isobornyl methacrylate, hydroxypropyl acrylate, a part of benzoyl peroxide, a part of ethyl acetate and a part of toluene to the reaction vessel, and react for 1 h under stirring and at a temperature of 78 °C;

[0045] III. Mix the remaining benzoyl peroxide, the remaining ethyl acetate, the remaining toluene and allyl glycidyl ether, and drop the mixed material into the reaction vessel at a constant rate within 1.5 h. After the dropping is completed, continue the reaction and stop when the viscosity increases to 2698 cp to obtain a glue solution;

[0046] IV. Add toluene diisocyanate, F51 epoxy resin and latent curing agent SC10208E to the glue solution obtained in step III, and disperse evenly at high speed; coat the glue solution on a PET release film using a 400-micron coater, leave it to dry for 0.5 h, and then put it into an oven and dry it at a temperature of 60 °C for 2 h to obtain a post-cured high-strength acrylate pressure-sensitive adhesive.

[0047] Example 3: A method for preparing a post-cured, high-strength acrylate pressure-sensitive adhesive is completed according to the following steps:

[0048] 1. Weigh 80 g of isooctyl acrylate, 12 g of methyl methacrylate, 12 g of 2-hydroxyethyl methacrylate, 8 g of itaconic acid, 0.8 g of benzoyl peroxide, 80 g of ethyl acetate, 20 g of toluene, 3 g of aziridine crosslinking agent, 25 g of AG80 epoxy resin, and 2 g of latent curing agent SC10208E;

[0049] 2. Add isooctyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, a part of benzoyl peroxide, a part of ethyl acetate, and a part of toluene into a reaction vessel, and react for 1 h under stirring at a temperature of 83 °C;

[0050] 3. Mix the remaining benzoyl peroxide, the remaining ethyl acetate, the remaining toluene, and itaconic acid, and drop the mixed material into the reaction vessel at a constant rate within 1.5 h. After the dropping is completed, continue the reaction and stop when the viscosity increases to 2880 cp to obtain a glue solution;

[0051] 4. Add aziridine crosslinking agent, epoxy resin AG80, and latent curing agent SC10208E to the glue solution obtained in step 3, disperse evenly at high speed, coat the glue solution on a PET release film using a 300-μm coater, air dry for 0.5 h, and then put it into an oven and dry at 55 °C for 1.5 h to obtain a post-cured high-strength acrylate pressure-sensitive adhesive.

[0052] Comparative Example 1: The difference between this comparative example and Example 1 is that no latent curing agent SC10208E is added. That is, in step 1, weigh 40 g of isooctyl acrylate, 35 g of butyl acrylate, 15 g of isobutyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 9 g of methacrylic acid, 0.8 g of benzoyl peroxide, 50 g of ethyl acetate, 50 g of toluene, 2 g of aluminum acetylacetonate, and 20 g of E44 epoxy resin. Other steps and parameters are the same as those in Example 1.

[0053] Comparative Example 2: The difference between this comparative example and Example 1 is that no E44 epoxy resin is added. That is, in step 1, weigh 40 g of isooctyl acrylate, 35 g of butyl acrylate, 15 g of methyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 9 g of methacrylic acid, 0.8 g of benzoyl peroxide, 50 g of ethyl acetate, 50 g of toluene, 2 g of aluminum acetylacetonate, and 3 g of latent curing agent SC10208E. Other steps and parameters are the same as those in Example 1.

[0054] Comparative Example 3: The difference between this comparative example and Example 1 is that toluene diisocyanate is used as the crosslinking agent. That is, in Step 1, 40 g of isooctyl acrylate, 35 g of butyl acrylate, 15 g of methyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 9 g of methacrylic acid, 0.8 g of dibenzoyl peroxide, 50 g of ethyl acetate, 50 g of toluene, 0.9 g of toluene diisocyanate, and 20 g of E44 epoxy resin and 3 g of latent curing agent SC10208E are weighed. Other steps and parameters are the same as those in Example 1.

[0055] Comparative Example 4: The difference between this comparative example and Example 1 is that the common latent curing agent dicyandiamide 3 g is used as the latent curing agent, and 3 g of latent curing agent SC10208E in Step 1 is replaced with 3 g of latent curing agent dicyandiamide. Other steps and parameters are the same as those in Example 1.

[0056] Comparative Example 5: The difference between this comparative example and Example 2 is that instead of using toluene diisocyanate as the crosslinking agent, 2 g of D230 amine crosslinking agent that can react with epoxy functional groups is used. That is, 0.8 g of toluene diisocyanate in Step 1 is replaced with 2 g of D230 amine crosslinking agent; other steps and parameters are the same as those in Example 2.

[0057] Next, the post-cured high-strength acrylate pressure-sensitive adhesives prepared in Examples 1 to 3 and the acrylate pressure-sensitive adhesives in Comparative Examples 1 to 5 will be subjected to the following performance tests:

[0058] The initial adhesion of the pressure-sensitive adhesive tape was tested with reference to GB / T 4852-2002 (rolling ball method); the holding power of the pressure-sensitive adhesive tape at room temperature was tested with reference to GB / T 4851-2014; the 180° peel strength of the pressure-sensitive adhesive tape at room temperature was tested with reference to GB / 2792-2014; the shear strength specimen after post-curing at 120 °C / 1 h was tested with reference to GB / T 7124-2008; the results are shown in Table 1:

[0059] Table 1 Performance of the Pressure-Sensitive Adhesive

[0060]

[0061] It can be seen from Table 1 that the pressure-sensitive adhesives prepared in Examples 1 to 3 have good pressure-sensitive adhesive properties. The test results of the initial adhesion are balls No. 9-10, the holding time is more than 24 h, and the peel strength is more than 1 kN / m. The pressure-sensitive adhesive has good post-curing ability, and the shear strength after high-temperature treatment is more than 13 MPa.

[0062] Combined with the performance analysis of Comparative Examples 1 to 4 and Example 1, the specific results are as follows:

[0063] (1) Comparing the technical solutions of Comparative Example 1 and Example 1, it can be seen from the data in the table that the pressure-sensitive properties of the pressure-sensitive adhesive prepared in Comparative Example 1 are comparable to those in Example 1, with relatively high initial tack, holding power, and 180° peel strength. However, since no latent curing agent was added to the system, the pressure-sensitive adhesive does not have post-curing ability. After post-curing at 120 °C for 1 h, the shear strength is only 1.14 MPa, which is much lower than the shear strength of the pressure-sensitive adhesive prepared in Example 1 after curing.

[0064] (2) Comparing the technical solutions of Comparative Example 2 and Example 1, it can be seen from the data in the table that the holding power and 180° peel strength of the pressure-sensitive adhesive prepared in Comparative Example 2 are comparable to those in Example 1, and the initial tack is slightly lower than that in Example 1. The reason is that no reinforcing agent E44 epoxy resin with certain tackiness was added in Comparative Example 2. At the same time, there is a lack of a reinforcing agent that reacts with the latent curing agent in the system, so the function of the latent curing agent cannot be exerted, and the pressure-sensitive adhesive does not have post-curing ability. After post-curing at 120 °C for 1 h, the shear strength is only 0.91 MPa, which is much lower than the shear strength of the pressure-sensitive adhesive after post-curing in Example 1.

[0065] (3) Comparing the technical solutions of Comparative Example 3 and Example 1, it can be seen from the data in the table that in Comparative Example 3, due to the failure to select an appropriate cross-linking agent and using isocyanate to cross-link the carboxyl-containing system, since the reaction rate between the isocyanate group functional group and the carboxyl group functional group is too fast, the viscosity of the adhesive liquid increases rapidly, resulting in difficulty in scraping and forming a film.

[0066] (4) Comparing the technical solutions of Comparative Example 4 and Example 1, it can be seen from the data in the table that in Comparative Example 5, the microcapsule-type latent curing agent was replaced with a conventional latent dicyandiamide curing agent, and gelation occurred after adding the curing agent, that is, a rapid reaction occurred between the active amino group and the carboxyl group in the pressure-sensitive adhesive system after the addition of dicyandiamide, and the pressure-sensitive adhesive liquid quickly gelled and could not be scraped into a film.

[0067] (5) Comparing the technical solutions of Comparative Example 5 and Example 2, it can be seen from Table 1 that the D230 amine cross-linking agent used in Comparative Example 5 can undergo a ring-opening reaction with the epoxy group (-C-O-C-) to achieve cross-linking of the pressure-sensitive adhesive, but the initial tack of the resulting adhesive film is very low. Due to poor wettability of the test piece, the holding power specimens prepared will quickly fall off, and both the peel and shear strengths after curing are very low.

Claims

1. A post-curing high-strength acrylate pressure-sensitive adhesive, characterized in that The acrylate pressure-sensitive adhesive is prepared from 70 to 90 parts by weight of soft monomer, 5 to 15 parts by weight of hard monomer, 7 to 12 parts by weight of functional monomer A1, 5 to 10 parts by weight of functional monomer A2, 0.5 to 1.5 parts by weight of initiator, 80 to 120 parts by weight of solvent, 0.5 to 10 parts by weight of crosslinking agent, 10 to 30 parts by weight of reinforcing agent, and 0.5 to 5 parts by weight of latent curing agent.

2. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, characterized in that The soft monomer is one or more of octadecyl acrylate, n-decyl methacrylate, butyl acrylate, isooctyl acrylate, ethyl acrylate, n-octyl acrylate, lauryl acrylate, tetradecyl acrylate, polyethylene glycol 400 diacrylate, and polypropylene glycol 400 diacrylate.

3. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, characterized in that The hard monomer is one or more of methyl methacrylate, vinyl acetate, ethyl methacrylate, isobutyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, tetrahydrofurfuryl methacrylate, styrene, and acrylonitrile.

4. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, characterized in that The functional monomer A1 is one or more of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, and 4-hydroxybutyl acrylate.

5. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, wherein The functional monomer A2 is a carboxyl group-containing functional monomer or an epoxy group-containing functional monomer. The carboxyl group-containing functional monomers include acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, maleic acid, and 2-acryloyloxyethyl succinic acid; the epoxy group-containing functional monomers include glycidyl acrylate, glycidyl methacrylate, glycidyl acrylate ether, glycidyl methacrylate ether, allyl glycidyl ether, 1,2-epoxy-4-vinylcyclohexane, and glycidyl ether of 4-hydroxybutyl acrylate. One or more of them are used, and the carboxyl group-containing functional monomers and the epoxy group-containing functional monomers are not used simultaneously.

6. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, characterized in that The initiator is one of benzoyl peroxide or azobisisobutyronitrile; the solvent is one or more of ethyl acetate, methyl ethyl ketone, toluene, and butyl acetate.

7. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, wherein When the functional monomer A2 is one or more of glycidyl acrylate, glycidyl methacrylate, glycidyl acrylate ether, glycidyl methacrylate ether, allyl glycidyl ether, 1,2-epoxy-4-vinylcyclohexane, and glycidyl ether of 4-hydroxybutyl acrylate, the crosslinking agent is one of toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate; when the functional monomer A2 is one of acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, maleic acid, and 2-acryloyloxyethyl succinic acid, the crosslinking agent is one of aziridine or acetylacetonate.

8. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, wherein The reinforcing agent is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenolic epoxy resin, o-cresol novolac epoxy resin, brominated epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, and aliphatic epoxy resin.

9. The post-curing type high-strength acrylate pressure-sensitive adhesive according to claim 1, wherein The latent curing agent is a microcapsule-type imidazole curing agent SC10208E.

10. The preparation method of a post-curing high-strength acrylate pressure-sensitive adhesive according to claim 1, characterized in that The specific preparation method is completed according to the following steps:

1. Weigh 70 to 90 parts by weight of soft monomer, 5 to 15 parts of hard monomer, 7 to 12 parts of functional monomer A1, 5 to 10 parts of functional monomer A2, 0.5 to 1.5 parts of initiator, 80 to 120 parts of solvent, 0.5 to 10 parts of crosslinking agent, 10 to 30 parts of reinforcing agent, and 0.5 to 5 parts of latent curing agent; 2. Add the soft monomer, hard monomer, functional monomer A1, a part of the initiator, and a part of the solvent weighed in step 1 into a reaction vessel, and react for 0.5 h to 1 h under stirring at a temperature of 75 °C to 83 °C; 3. Mix the remaining initiator, the remaining solvent, and functional monomer A2, and drop the mixed material into the reaction vessel at a constant rate within the time range of 1 h to 1.5 h. After the dropping is completed, continue the reaction and stop when the viscosity increases to 2500 cp to 3000 cp to obtain a glue solution; 4. Add the crosslinking agent, reinforcing agent, and latent curing agent to the glue solution obtained in step 3, disperse evenly, coat the glue solution on a PET release film using a coater with a thickness of 100 - 600 microns, leave it to dry for 0.5 h to 2 h, and then put it into an oven and dry it at a temperature of 50 °C to 60 °C for 1 h to 2 h to obtain a post-cured high-strength acrylate pressure-sensitive adhesive.

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