Solvent-resistant pressure-sensitive adhesive composition, preparation method thereof and application

Abstract

The present invention discloses a solvent-resistant pressure-sensitive adhesive composition, a preparation method thereof and an application. The solvent-resistant pressure-sensitive adhesive composition includes: a polyacrylate polymer and a side chain grafted on the main chain of the polyacrylate polymer; the side chain includes a liquid polysulfide rubber with a thiol group at the end; the liquid polysulfide rubber is connected to the polyacrylate polymer through a ring-opening addition reaction between the thiol group and an epoxy group-containing side chain on the polyacrylate polymer. When this polysulfide rubber is mixed with the epoxy group-containing polyacrylate, the thiol group at the end undergoes a chemical reaction with the epoxy group, thereby entering the polyacrylate main chain to form an IPN structure, so that the solvent-resistant pressure-sensitive adhesive composition provided by the present invention has good flexibility, high shear strength and peel strength, and at the same time has good solvent and oil resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to a solvent-resistant pressure-sensitive adhesive composition, a preparation method thereof and an application thereof. Background Art

[0002] The description in this part only provides background information related to the disclosure of the present invention and does not constitute prior art.

[0003] Polyacrylate pressure-sensitive adhesives have many unique properties compared with pressure-sensitive adhesives of other materials (such as rubber-based, silicone, polyurethane, etc.), such as excellent aging resistance (especially resistance to ultraviolet light aging), excellent optical transparency, and moderate price, and are widely used in transportation, electronics, household appliances and construction markets.

[0004] Common polyacrylate pressure-sensitive adhesives are usually randomly copolymerized from soft monomers such as isooctyl acrylate (IOA) or 2-ethylhexyl acrylate (2-EHA), hard monomers such as isobornyl acrylate (IBOA), methyl methacrylate (MMA), and functional monomers such as acrylic acid (AA), methacrylic acid (MAA), and 2-hydroxyethyl acrylate (2-HEA). Such pressure-sensitive adhesives have relatively ideal peel strength and shear strength for most bonding surfaces.

[0005] However, polyacrylate pressure-sensitive adhesives generally have poor solvent resistance, and their viscosity will drop sharply under the immersion of solvents or oils, which limits some of their application scenarios.

[0006] There are many methods to improve the solvent resistance of polyacrylate pressure-sensitive adhesives. For example, Chinese Patent CN102775942B provides a fluorinated acrylate pressure-sensitive adhesive and a preparation method thereof. The feature is that the hard monomer in the fluorinated acrylate pressure-sensitive adhesive contains at least 2.5 wt% of a fluorinated hard monomer. The number-average molecular weight of the prepared fluorinated acrylate pressure-sensitive adhesive is 9,000 - 300,000, and the pressure-sensitive adhesive has low surface properties, reduces the transfer of silicon during the separation of the adhesive from the release paper, and improves the bonding strength between the adhesive and the adherend. The production process of this fluorinated acrylate pressure-sensitive adhesive is simple and easy to operate, and it has solvent resistance and good cohesion and bonding strength. However, such fluorinated acrylate pressure-sensitive adhesives have a high cost and their bonding performance is still not high.

[0007] Chinese Patent CN109852263 discloses a solvent-resistant pressure-sensitive adhesive. By mass percentage, the solvent-resistant pressure-sensitive adhesive comprises the following raw material components: 15%-25% of SIS, 12%-18% of hydrogenated petroleum resin, 1%-5% of hydrogenated terpene phenolic resin, 0.5%-1.5% of polyfunctional crosslinking agent, 0.1%-1% of monofunctional crosslinking agent, 0.1‰-1‰ of photoinitiator, 0.1%-0.5% of antioxidant, 0.1‰-1‰ of light stabilizer, 0.5‰-1.5‰ of crosslinking agent A, and 50%-70% of solvent, with the sum being 100%. The solvent-resistant pressure-sensitive adhesive and the foam double-sided tape prepared from the solvent-resistant pressure-sensitive adhesive can have good solvent resistance while maintaining high bonding strength and excellent impact resistance. However, due to its main component being SIS synthetic rubber (with carbon-carbon unsaturated double bonds in the main chain), its heat resistance and weather resistance are both poor.

[0008] It is necessary to develop a polyacrylate pressure-sensitive adhesive that can be solvent-resistant, oil-resistant, moderately priced, and has excellent adhesion performance to expand its application scenarios (such as pressure-sensitive labels for automobile engines, adhesive tapes for lithium batteries, etc.).

[0009] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present invention. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a solvent-resistant pressure-sensitive adhesive composition, its preparation method and application, and solve the problem that the pressure-sensitive adhesives in the prior art cannot achieve a balance of solvent resistance, oil resistance, moderate price, and excellent adhesion performance.

[0011] To solve the above technical problem, the present invention provides a solvent-resistant pressure-sensitive adhesive composition, which comprises: a polyacrylate polymer and a side chain grafted onto the main chain of the polyacrylate polymer; the side chain comprises a liquid polysulfide rubber with a mercapto group at the end; the liquid polysulfide rubber is connected to the polyacrylate polymer through a ring-opening addition reaction between the mercapto group and the epoxy group-containing side chain on the polyacrylate polymer.

[0012] Further, the polyacrylate polymer is formed by copolymerizing a first monomer and a second monomer; the first monomer is selected from acrylic acid alkyl ester monomers; the second monomer is selected from acrylic acid ester monomers with an epoxy group at the end of the group connected to the ester group.

[0013] Further, the alkyl carbon atom number of the first monomer is 1-12.

[0014] Further, the first monomer and / or the second monomer is a methacrylate monomer.

[0015] Further, the first monomer includes any one or a combination of two or more of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, where methyl is optional.

[0016] Further, the second monomer includes any one or a combination of two of glycidyl acrylate monomer and glycidyl (meth)acrylate monomer.

[0017] Further, the mass fraction of the first monomer in the polyacrylate polymer is 75-97%.

[0018] Further, the mass fraction of the second monomer in the polyacrylate polymer is 3-25%.

[0019] Further, both ends of the liquid polysulfide rubber are mercapto groups.

[0020] Further, the molecular weight of the liquid polysulfide rubber is 800-8000; in the solvent-resistant pressure-sensitive adhesive composition, the molar amount of the liquid polysulfide rubber is lower than the reaction stoichiometry of the molar amount of the epoxy group.

[0021] Further, the viscosity of the solvent-resistant pressure-sensitive adhesive composition is 200-50000 cPs.

[0022] The second aspect of the present invention also provides a preparation method of the above solvent-resistant pressure-sensitive adhesive composition, which includes:

[0023] Providing an acrylate polymer and a liquid polysulfide rubber; the main chain of the acrylate polymer has a side chain, and the side chain has an epoxy group; both ends of the liquid polysulfide rubber have mercapto groups.

[0024] Mixing the acrylate polymer and the liquid polysulfide rubber, and causing a ring-opening addition reaction between the mercapto group and the epoxy group to obtain a solvent-resistant pressure-sensitive adhesive composition.

[0025] The third aspect of the present invention also provides a solvent-resistant pressure-sensitive tape, which includes a tape substrate and an adhesive layer arranged in a laminated manner; the adhesive layer is at least formed by coating and drying and curing the above solvent-resistant pressure-sensitive adhesive composition.

[0026] By means of the above technical solutions, the beneficial effects of the present invention are as follows:

[0027] The composition provided by the present invention is a polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive. The liquid polysulfide rubber with mercapto groups at both ends is a low-molecular-weight polymer, which has excellent properties such as low-temperature flexibility, solvent resistance, and stress relaxation. When this polysulfide rubber is mixed with the polyacrylate containing epoxy groups, the thiol groups at the ends react chemically with the epoxy groups, thereby entering the polyacrylate main chain to form an IPN structure. This makes the whole system have good flexibility, high shear strength and peel strength, and at the same time, good solvent and oil resistance. Detailed implementation mode

[0028] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

[0029] It should be noted that in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects, and there is no sequence between them, nor can they be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0030] A solvent-resistant pressure-sensitive adhesive composition according to a preferred embodiment of the present invention includes: a polyacrylate polymer and a side chain grafted on the main chain of the polyacrylate polymer; the side chain includes a liquid polysulfide rubber with a mercapto group at the end; the liquid polysulfide rubber is connected to the polyacrylate polymer through a ring-opening addition reaction between the mercapto group and the epoxy group-containing side chain on the polyacrylate polymer.

[0031] Corresponding to the above composition, the embodiment of the present invention also provides a preparation method for preparing the above composition, which includes the following steps:

[0032] Provide an acrylate polymer and a liquid polysulfide rubber; the main chain of the acrylate polymer has a side chain, and the side chain has an epoxy group; both ends of the liquid polysulfide rubber have mercapto groups.

[0033] Mix the acrylate polymer and the liquid polysulfide rubber, and make the mercapto group and the epoxy group undergo a ring-opening addition reaction to obtain a solvent-resistant pressure-sensitive adhesive composition.

[0034] As an application of the technical solution of the present invention, the embodiment of the present invention also provides a solvent-resistant pressure-sensitive tape, which includes a tape substrate and an adhesive layer stacked.

[0035] The adhesive layer is at least formed by coating, drying and curing the above-mentioned solvent-resistant pressure-sensitive adhesive composition.

[0036] As some typical embodiments of the present invention, by using the technical solutions provided by the present invention, a polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive can be produced, which not only has good flexibility, high shear strength and peel strength, but also has good solvent and oil resistance. The polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive composition mentioned in the present invention is usually coated on a substrate (PET film, PP film, PE film, PVC film, paper, non-woven fabric, etc.) in a liquid form, and then through the processes of heating, drying and curing in an oven, different types of pressure-sensitive adhesive tape products are prepared. Of course, the application of the composition provided by the present invention is not limited to the preparation of tapes, and other embodiments such as preparing it into glue or coating are also possible.

[0037] More specifically, the polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive composition mentioned in the present invention can be composed of the following several components: a poly(meth)acrylate containing an epoxy functional group as component (A), and a low-molecular-weight liquid polysulfide rubber containing mercapto groups (-SH) at both ends as component (B).

[0038] It should be noted that unless otherwise specified, the percentages mentioned in the following examples of the present invention are all weight percentages.

[0039] The poly(meth)acrylate containing an epoxy functional group as component (A) contains the following monomer components:

[0040] (a1) A (meth)acrylate monomer with an alkyl group having 1 to 12 carbon atoms.

[0041] (a2) A (meth)acrylate monomer containing an epoxy functional group.

[0042] In one embodiment of the present invention, examples of the (meth)acrylate in component a1) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc., including their possible isomeric forms. Preferably, the (meth)acrylate in component a1) is selected from methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, or a mixture of two or more thereof. More preferably, the (meth)acrylate in component a1) is selected from butyl (meth)acrylate, methyl (meth)acrylate, isooctyl (meth)acrylate, or a mixture of two or more thereof.

[0043] In one embodiment of the present invention, component a2) is a glycidyl (meth)acrylate monomer (Glycidylmethacrylate–GMA or Glycidyl acrylate–GA).

[0044] The amount of monomer a1) is 75-97% by weight, preferably 85-95% by weight, based on the total weight of all monomers (i.e., the one or more monomers) used.

[0045] Based on the total weight of all monomers (i.e., the one or more monomers) used, the amount of monomer a2) is generally 3-25% by weight, preferably 5-15% by weight. The inventors have found that monomer a2) in this amount range is beneficial to the solvent resistance and adhesion of the pressure-sensitive adhesive.

[0046] The liquid polysulfide rubber with mercapto groups (-SH) at both ends as component (B) is a low molecular weight polymer, which has excellent properties such as low temperature flexibility, solvent resistance, and stress relaxation. When the polysulfide rubber is mixed with component (A) of the polyacrylate containing epoxy groups, the terminal thiol groups react chemically with the epoxy resin, thereby entering the polyacrylate main chain to form an IPN structure, making the system have good flexibility, high shear strength and peel strength, and at the same time, good solvent and oil resistance. The content of the liquid polysulfide rubber with mercapto groups (-SH) at both ends as component (B) in the pressure-sensitive adhesive composition should be consistent with the molar number of the epoxy group-containing monomer in component (A), and its molecular weight is between 800 and 8000. If the content of the liquid polysulfide rubber with mercapto groups (-SH) at both ends is too high, a "free" polysulfide rubber component will be formed, resulting in potential "migration" problems, thereby affecting the long-term aging performance of the pressure-sensitive adhesive.

[0047] The viscosity of the polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive composition mentioned in the present invention before coating should be between 200 and 50,000 cPs, and more preferably between 1,500 and 16,000 cPs. Too high or too low viscosity is not conducive to the coating of the pressure-sensitive adhesive composition.

[0048] Regarding the source of the above polyacrylate, it can be synthesized from monomers with a specific ratio, or a polymer with the same molecular structure can be purchased commercially, or synthesized by entrusting a third party. All acquisition channels fall within the scope of the embodiments protected by the present invention.

[0049] The following several specific examples are used to fully illustrate the technical solution of the present invention. However, it should be noted that the following examples are only used to exemplarily illustrate the present invention and do not limit the protection scope of the present invention.

[0050] In the following partial examples, the details of various materials used are shown in Table 1 below.

[0051] Table 1 Raw material information to be used in the examples

[0052]

[0053] Example 1

[0054] This example demonstrates the preparation of a poly(meth)acrylate containing epoxy functional groups as component (A), which is specifically as follows:

[0055] 2-EHA, BA, GMA, ethyl acetate, and the free radical thermal initiator Vazo TM 64 were added to a 5-liter flask filled with nitrogen and equipped with a water bath heating and reflux device according to the composition in Table 2. Under stirring, the reaction was stopped after 24 hours at 60 °C. After cooling, a transparent viscous liquid was obtained, which is the poly(meth)acrylate (A) containing epoxy functional groups. This substance can be directly used in subsequent reactions without any treatment.

[0056] The structural formula of the synthesized acrylate is shown in the following formula:

[0057]

[0058] Where R1 is an H atom or a methyl group; R2 is a (meth)acrylate monomer or mixture with an alkyl group having 1 to 12 carbon atoms

[0059] According to the above process, using the raw material selection and ratio shown in Table 2, poly(meth)acrylates A1 - A5 containing epoxy functional groups were obtained.

[0060] Table 2 Raw materials and ratios in Example 1

[0061] <![CDATA 2-EHA > <![CDATA BA > <![CDATA GMA > <![CDATA Ethyl acetate > <![CDATA Vazo TM 64 > <![CDATA A1 > <![CDATA 49 > <![CDATA 48 > <![CDATA 3 > <![CDATA 150 > <![CDATA 0.2 > <![CDATA A2 > <![CDATA 48 > <![CDATA 47 > <![CDATA 5 > <![CDATA 150 > <![CDATA 0.2 > <![CDATA A3 > <![CDATA 45 > <![CDATA 45 > <![CDATA 10 > <![CDATA 150 > <![CDATA 0.2 > <![CDATA A4 > <![CDATA 43 > <![CDATA 42 > <![CDATA 15 > <![CDATA 150 > <![CDATA 0.2 > <![CDATA A5 > <![CDATA 38 > <![CDATA 37 > <![CDATA 25 > <![CDATA 150 > <![CDATA 0.2 >

[0062] Example 2

[0063] This example illustrates the preparation of the polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive composition provided by the above technical solution, which is specifically as follows:

[0064] Add the epoxy-functional poly(meth)acrylate (A) prepared in Example 1 to a 1-liter three-necked round-bottom flask equipped with a water bath heating device, nitrogen inlet, and reflux device according to the measurements in Table 3, and start the stirring device. Weigh the liquid polysulfide rubber (B) with mercapto groups (-SH) at both ends and add it to (A). Continue stirring until completely mixed evenly to obtain a clear and viscous liquid (it should be noted that this liquid needs to be coated within half an hour). The structural formula of the liquid polysulfide rubber used is shown as follows:

[0065]

[0066] According to the above method, the polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive composition is obtained by using the raw materials and ratios in Table 3 below, and is labeled as Sample 1 - Sample 15.

[0067] Table 3 Raw materials and ratios in Example 2

[0068] A1 A2 A3 A4 A5 B1 B2 B3 Sample 1 50 2.11 Sample 2 50 6.33 Sample 3 50 15.83 Sample 4 50 3.52 Sample 5 50 10.55 Sample 6 50 26.38 Sample 7 50 7.04 Sample 8 50 21.1 Sample 9 50 52.76 Sample 10 50 10.56 Sample 11 50 31.65 Sample 12 50 79.14 Sample 13 50 17.6 Sample 14 50 52.75 Sample 15 50 131.9

[0069] Application Example 1

[0070] This example illustrates the application of the above composition in the preparation of pressure-sensitive tapes and the testing of adhesion performance, which is specifically as follows:

[0071] Coat the above samples on a 50-micron PET film according to the coating method of the pressure-sensitive adhesive composition, control the dry adhesive thickness to be 75 microns, and obtain a single-sided tape after drying for evaluating the 180-degree peel strength of the tape.

[0072] The polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive composition mentioned in this example can be coated on a 50-micron thick PET substrate in a liquid form by a traditional coating method, and then through a drying and curing process to form a pressure-sensitive adhesive film with the required thickness.

[0073] The temperature setting of the oven and the line speed can refer to the following parameters:

[0074] Zone1: 40 °C, length 8 m.

[0075] Zone2: 70 °C, length 8 m.

[0076] Zone3: 90 °C, length 8 m.

[0077] Zone 4: 110 °C, length 8 m.

[0078] The linear velocity of the substrate in the oven is 15 m / min.

[0079] For each sample in Example 1, the corresponding pressure-sensitive tape was prepared, and the adhesion performance and solvent resistance performance were tested. The specific tape test methods are as follows:

[0080] 1. 180-degree peel strength (before solvent immersion)

[0081] The test method for 180-degree peel strength was carried out according to the national standard (GB 2792-81) method.

[0082] The tape was cut into strips 1 inch (2.54 cm) wide and longer than 200 mm, and gently attached to a standard stainless steel test plate (meeting the requirements of GB / T 3280-1992). A 2.04 kg hard rubber roller was rolled on the specimen at a speed of about 300 mm / min. Note that when rolling, only the force generated by the roller mass should be applied to the specimen, and roll back and forth three times. Place it in an environment controlled at a constant temperature of 23 °C ± 2 °C and a constant humidity of 50% RH ± 5% RH for 72 hours. Use a standard tensile machine (meeting the requirements of JB706—77 for testing machines) to test the peel force at a speed of 12 inches / minute (303 mm / min). Each sample was tested three times, and the average value was taken, with the unit of N / mm.

[0083] 2. 180-degree peel strength (after solvent immersion)

[0084] The sample preparation method is the same as above. The difference is that after the preparation of the tape sample, it was immersed in the following solvents for 24 hours, then the sample was taken out, wiped clean, and the 180-degree peel strength was tested using the same method as in Method 1 to compare the peel forces before and after solvent immersion.

[0085] Solvent 1: Isopropyl alcohol; Solvent 2: Engine oil (10W30); Solvent 3: Sulfuric acid aqueous solution with pH 4; Solvent 4: Sodium hydroxide aqueous solution with pH = 10; Solvent 5: Lithium battery electrolyte (lithium hexafluorophosphate / propylene carbonate)

[0086] According to the above evaluation method, the test results of the tape samples are shown in Table 4.

[0087] Table 4 Test results of the sample pressure-sensitive tape

[0088] Initial peeling Solvent 1 Solvent 2 Solvent 3 Solvent 4 Solvent 5 Sample 1 0.54 0.45 0.45 0.54 0.58 0.48 Sample 2 0.66 0.68 0.70 0.7 0.66 0.77 Sample 3 0.78 0.71 0.81 0.83 0.84 0.87 Sample 4 0.69 0.54 0.50 0.72 0.71 0.56 Sample 5 0.74 0.80 0.70 0.70 0.80 0.80 Sample 6 0.88 0.91 0.98 0.90 0.91 0.93 Sample 7 0.70 0.66 0.73 0.77 0.69 0.77 Sample 8 0.85 0.80 0.85 0.87 0.88 0.90 Sample 9 1.02 1.10 1.00 1.10 1.09 1.05 Sample 10 0.71 0.77 0.78 0.76 0.75 0.84 Sample 11 0.93 0.90 0.98 0.99 1.00 0.95 Sample 12 1.22 1.20 1.20 1.21 1.30 1.31 Sample 13 0.87 0.88 0.88 0.90 0.89 0.92 Sample 14 1.10 1.10 1.11 1.20 1.12 1.11 Sample 15 0.87 0.89 0.90 0.85 0.92 0.94

[0089] Based on the above test results, it is clear that the 15 pressure-sensitive tape samples provided in the above embodiments have very high solvent resistance and alkaline solution resistance, and the bond strength after being corroded by the solvent has not decreased significantly.

[0090] Comparative Example 1

[0091] This comparative example illustrates the preparation of a pressure-sensitive adhesive composition, the preparation and testing of pressure-sensitive tapes, which are specifically as follows:

[0092] This comparative example is the same as Samples 13 - 15 in Example 2, but the difference is that GMA used in Component A is replaced with an equal mass of BA.

[0093] As a result, the branched chain of the polyacrylate of the present invention no longer has epoxy end groups and cannot react with liquid polysulfide rubber to form a network structure.

[0094] Correspondingly, Samples 16 - 18 (B1 / B2 / B3) are obtained in sequence, and their solvent resistance is tested. The results are shown in Table 5 below.

[0095] Table 5 Test Results of Sample Pressure-Sensitive Tapes

[0096] Initial peeling Solvent 1 Solvent 2 Solvent 3 Solvent 4 Solvent 5 Sample 16 0.41 0.20 0.12 Direct detachment 0.15 Direct detachment Sample 17 0.50 Direct detachment Direct detachment Direct detachment 0.05 Direct detachment Sample 18 0.64 Direct detachment 0.20 Direct detachment 0.31 Direct detachment

[0097] As shown by the above comparative cases, forming specific chemical bond connections between the main chain of polyacrylate and liquid polysulfide rubber to form a specific polymer network is the key technical means to achieve solvent resistance. Moreover, the above technical means not only improve the solvent resistance but also synchronously improve the initial bond strength, having a more excellent comprehensive effect.

[0098] Example 3

[0099] This example illustrates the preparation of a pressure-sensitive adhesive composition, the preparation and testing of pressure-sensitive tapes, which are specifically as follows:

[0100] This Example 3 is generally the same as Samples 13 - 15 in Example 2. The main difference is that the binary first monomer is replaced with a single-component monomer, and the combination of 2-EHA and BA is replaced with an equivalent molar amount of pure 2-EHA and pure BA respectively, and the addition amounts of other raw materials remain unchanged.

[0101] As a result, Samples 19 - 21 (pure 2-EHA, B1 / B2 / B3) and Samples 22 - 24 (pure BA, B1 / B2 / B3) are formed, and their solvent resistance is tested. The results are shown in Table 6 below.

[0102] Table 6 Test Results of Sample Pressure-Sensitive Tapes

[0103]

[0104]

[0105] In Example 3, a single-component first monomer was used. In actual experiments, it was observed that the resulting sample still had a considerable degree of aging resistance. However, after solvent erosion, a slight decrease in bond strength was still visible.

[0106] Therefore, in order to achieve the best solvent resistance effect, the present invention preferably should be implemented in a manner using a two-component first monomer, especially the combination of 2-EHA and BA exemplified in Example 1.

[0107] The inventor of the present invention analyzed that the above phenomenon should be due to the fact that the side chains of the pure single-component first monomer are completely the same, the molecular chain composition is relatively single, and the complexity is low, which is not conducive to forming a network structure with a higher degree of entanglement, thereby reducing the fixing strength of the liquid polysulfide rubber to the overall network structure, and then resulting in some decline in its solvent resistance. In the above optimal embodiment, a two-component monomer composed of a large substituent and a small substituent is used, which improves the randomness degree of the polymer molecular chain, and then enhances the entanglement degree of the pressure-sensitive adhesive, thereby strengthening the solvent resistance.

[0108] Based on the above examples and comparative examples, it can be clearly seen that the composition provided by the embodiments of the present invention is a polyacrylate / polysulfide rubber hybrid pressure-sensitive adhesive. The liquid polysulfide rubber with mercapto groups at both ends is a low-molecular-weight polymer, which has excellent properties such as low-temperature flexibility, solvent resistance, and stress relaxation. When this polysulfide rubber is mixed with a polyacrylate containing epoxy groups, the terminal thiol groups react chemically with the epoxy groups, thereby entering the polyacrylate main chain to form an IPN structure, making the whole system have good flexibility, high shear strength and peel strength, and at the same time, good solvent and oil resistance.

[0109] The above-described embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A solvent-resistant pressure-sensitive adhesive composition, characterized in that, Comprising: A polyacrylate polymer and a side chain grafted onto the main chain of the polyacrylate polymer; the side chain includes a liquid polysulfide rubber with a mercapto group at the end; the liquid polysulfide rubber is connected to the polyacrylate polymer through a ring-opening addition reaction between the mercapto group and an epoxy group-containing side chain on the polyacrylate polymer; Wherein, the polyacrylate polymer is formed by copolymerizing a first monomer and a second monomer; the first monomer is selected from acrylate monomers; the second monomer is selected from acrylate monomers with an epoxy group at the end of the group connected to the ester group; The mass fraction of the first monomer in the polyacrylate polymer is 75-97%; and / or, the mass fraction of the second monomer in the polyacrylate polymer is 3-25%; both ends of the liquid polysulfide rubber are mercapto groups.

2. The solvent-resistant pressure-sensitive adhesive composition according to claim 1, characterized in that, The alkyl carbon atom number of the first monomer is 1-12; and / or, the first monomer and / or the second monomer is a methacrylate monomer.

3. The solvent-resistant pressure-sensitive adhesive composition according to claim 2, characterized in that, The first monomer includes any one or a combination of two or more of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, where methyl is optional; and / or, the second monomer includes any one or a combination of two of glycidyl acrylate monomer and glycidyl methacrylate monomer.

4. The solvent-resistant pressure-sensitive adhesive composition according to claim 1, wherein The molecular weight of the liquid polysulfide rubber is 800-8000; in the solvent-resistant pressure-sensitive adhesive composition, the mole number of the liquid polysulfide rubber is lower than the reaction stoichiometry of the mole number of the epoxy group.

5. The solvent-resistant pressure-sensitive adhesive composition according to claim 1, characterized in that, The viscosity of the solvent-resistant pressure-sensitive adhesive composition is 200-50000 cPs.

6. A method for preparing the solvent-resistant pressure-sensitive adhesive composition according to any one of claims 1-5, characterized in that, Comprising: Providing an acrylate polymer and a liquid polysulfide rubber; the main chain of the acrylate polymer has a side chain with an epoxy group; both ends of the liquid polysulfide rubber have mercapto groups; mixing the acrylate polymer and the liquid polysulfide rubber, and allowing the mercapto group and the epoxy group to undergo a ring-opening addition reaction to obtain a solvent-resistant pressure-sensitive adhesive composition.

7. A solvent-resistant pressure-sensitive tape, characterized in that, Comprising a tape substrate and an adhesive layer stacked; the adhesive layer is formed by coating and drying and curing at least the solvent-resistant pressure-sensitive adhesive composition according to any one of claims 1-5.

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