Acrylic pressure-sensitive adhesive polymer, acrylic adhesive, adhesive tape and preparation method and application thereof

Abstract

The invention discloses an acrylic pressure-sensitive adhesive polymer, an acrylic adhesive, an adhesive tape and a preparation method and application thereof. The acrylic pressure-sensitive adhesive polymer is prepared from an acrylic monomer, a styrene monomer and an isoprene monomer through a polymerization reaction. The preparation method of the acrylic adhesive comprises the step of uniformly mixing the acrylic pressure-sensitive adhesive polymer with the tackifying resin, the antioxidant, the curing agent and the solvent to prepare the acrylic adhesive. The acrylic adhesive is applied to at least one side surface of a base material, and drying is performed to prepare the low-modulus high-cohesion adhesive tape. A thermal polymerization technology is adopted, and styrene and isoprene monomers are introduced into a reaction system for polymerization, so that the molecular strength of the polymer can be remarkably improved, the problem of overhigh modulus of the polymer can be effectively controlled, the polymer has the characteristics of high strength and low modulus, and the adhesive tape with low modulus and high cohesion characteristics is prepared; and the thin and narrow application requirements in large-size electronic products are met.

Description

Technical Field

[0001] The invention relates to an adhesive and an adhesive tape, in particular to an acrylic pressure-sensitive adhesive polymer, an acrylic adhesive, an adhesive tape with low modulus and high cohesion characteristics, and a preparation method and application thereof, belonging to the technical field of pressure-sensitive adhesives. Background Art

[0002] With the rapid development of information technology and the continuous innovation of technology, the requirements for electronic products in the electronic consumer field are getting higher and higher, especially the electronic tapes related to display modules. This is because the design of electronic products tends to be light, convenient, large-screen and intelligent. This design has higher requirements than ever before for the optical weather resistance and dimensional stability of electronic displays. Therefore, electronic tapes in the display module direction also face more stringent testing challenges.

[0003] Because electronic products need to be designed to be thin and light, a large number of plastic materials are introduced, such as PC, PMMA, etc.; because of the high screen-to-body ratio design of electronic products, the electronic tapes used in them also tend to be thinner and longer; in the face of more and more plastic materials and increasingly thinner and longer applications, the dimensional stability and assembly reliability of products under strict weather resistance test conditions face higher requirements.

[0004] Currently available acrylic tapes usually have the problem of low modulus at low frequency and high modulus at high frequency, or low modulus at low frequency and low modulus at high frequency; such tapes usually have the problem that the colloid is hard at low temperature, which is not conducive to effective bonding on narrow sizes, and the colloid is soft at high temperature, resulting in the inability to maintain good dimensional stability on plastic materials; or the colloid has a small molecular weight, and is easy to overflow on narrow sizes, and the colloid is soft at high temperature, resulting in the inability to maintain good dimensional stability on plastic materials. Summary of the invention

[0005] The main purpose of the present invention is to provide an acrylic pressure-sensitive adhesive polymer and a preparation method thereof to overcome the deficiencies in the prior art.

[0006] Another object of the present invention is to provide an acrylic adhesive and a preparation method thereof.

[0007] Another object of the present invention is to provide an adhesive tape with low modulus and high cohesion properties and a preparation method and application thereof.

[0008] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: The embodiment of the present invention provides an acrylic pressure-sensitive adhesive polymer, which is prepared by polymerization reaction of acrylic monomers, styrene monomers and isoprene monomers.

[0009] In some embodiments, the raw materials for preparing the acrylic pressure-sensitive adhesive polymer include the following components: a hard acrylic monomer, a soft acrylic monomer, a functional acrylic monomer, a styrene monomer, an isoprene monomer, an initiator, an inhibitor, and a solvent.

[0010] The embodiment of the present invention also provides a method for preparing an acrylic pressure-sensitive adhesive polymer, which comprises: subjecting a reaction system comprising a hard acrylic monomer, a soft acrylic monomer, a functional acrylic monomer, a styrene monomer, an isoprene monomer, an initiator, an inhibitor and a first solvent to a polymerization reaction to obtain an acrylic pressure-sensitive adhesive polymer.

[0011] The embodiment of the present invention also provides an acrylic pressure-sensitive adhesive polymer prepared by the above preparation method.

[0012] The embodiment of the present invention further provides a method for preparing an acrylic adhesive, which comprises: uniformly mixing the acrylic pressure-sensitive adhesive polymer with a tackifying resin, an antioxidant, a curing agent, and a second solvent to prepare the acrylic adhesive.

[0013] Correspondingly, the embodiment of the present invention also provides an acrylic adhesive prepared by the above preparation method.

[0014] Furthermore, an embodiment of the present invention also provides a method for preparing a low modulus and high cohesion tape, which comprises: applying the acrylic adhesive to at least one surface of a substrate, and drying to obtain the low modulus and high cohesion tape.

[0015] Correspondingly, the embodiment of the present invention also provides a low modulus and high cohesion adhesive tape prepared by the above-mentioned preparation method.

[0016] Furthermore, an embodiment of the present invention also provides the use of the aforementioned low modulus and high cohesion tape in the preparation of electronic products.

[0017] Compared with the prior art, the beneficial effects of the present invention include: 1) The acrylic pressure-sensitive adhesive polymer provided by the present invention is prepared by thermal polymerization technology. By introducing styrene and isoprene monomers into the reaction system for polymerization, the molecular strength of the polymer can be significantly improved and the problem of excessively high modulus of the polymer can be effectively controlled, so that the polymer has the characteristics of high strength and low modulus; 2) The preparation method of the acrylic adhesive provided by the present invention adopts a variety of resin combinations, which can significantly improve the bonding strength of the product; and adopts a composite curing agent type heat curing cross-linking reaction system, which can significantly improve the colloid bonding strength and temperature resistance. DETAILED DESCRIPTION

[0018] In order to meet the stringent demands for adhesive tapes in the current and future markets, the inventors of the present invention have conducted extensive and in-depth research and have provided a method for adjusting the thermomechanical properties of the resulting colloid by introducing styrene and isoprene monomers into acrylic polymerization, thereby obtaining an acrylic colloid with small modulus and high strength. The colloid has a small low-temperature modulus and a relatively large high-temperature modulus, and exhibits good bonding effects and high dimensional stability. Its characteristics are more suitable for the application requirements of narrow and long slender products in large-size electronic products.

[0019] The technical solution, its implementation process and principle will be further explained as follows.

[0020] As one aspect of the technical solution of the present invention, an acrylic pressure-sensitive adhesive polymer is prepared by polymerization reaction of acrylic monomers, styrene monomers and isoprene monomers.

[0021] In some embodiments, the acrylic monomers include a combination of hard acrylic monomers, soft acrylic monomers and functional acrylic monomers. The combination of hard and soft monomers in the synthesis of acrylic glue in the present invention can adjust the physical properties of the colloid and balance the strength and hardness of the colloid. The functional monomers give the colloid an effective reaction with the curing agent, which can further enhance the performance of the colloid.

[0022] Furthermore, the hard acrylic monomer may include any one or a combination of two or more of methyl methacrylate, methyl acrylate, vinyl acetate, isobornyl methacrylate, acrylonitrile, acrylamide, etc., but is not limited thereto.

[0023] Furthermore, the soft acrylic monomer may include any one or a combination of two or more of n-butyl acrylate, ethyl acrylate, n-octyl acrylate, butyl acrylate, n-hexyl acrylate, n-pentyl acrylate, n-heptyl acrylate, isooctyl acrylate, isooctyl methacrylate, n-nonyl acrylate, lauryl acrylate, etc., but is not limited thereto.

[0024] Furthermore, the functional acrylic monomer may include any one or a combination of two or more of maleic anhydride, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylic acid, itaconic acid, methacrylic acid, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc., but is not limited thereto.

[0025] In some more specific embodiments, the raw materials for preparing the acrylic pressure-sensitive adhesive polymer include the following components: hard acrylic monomers, soft acrylic monomers, functional acrylic monomers, styrene monomers, isoprene monomers, initiators, inhibitors and solvents.

[0026] In some more preferred specific embodiments, the raw materials for preparing the acrylic pressure-sensitive adhesive polymer include the following components, calculated by mass percentage: 5-15 parts of hard acrylic monomer, 20-40 parts of soft acrylic monomer, 1-3 parts of functional acrylic monomer, 3-5 parts of styrene monomer, 10-15 parts of isoprene monomer, 0.5-2 parts of initiator, 1-3 parts of inhibitor and 50-150 parts of solvent.

[0027] As one aspect of the technical solution of the present invention, a method for preparing an acrylic pressure-sensitive adhesive polymer involves: subjecting a reaction system comprising a hard acrylic monomer, a soft acrylic monomer, a functional acrylic monomer, a styrene monomer, an isoprene monomer, an initiator, an inhibitor and a first solvent to a polymerization reaction to obtain an acrylic pressure-sensitive adhesive polymer.

[0028] The preparation method provided by the present invention is conceived as follows: mainly using acrylic monomers and a certain amount of styrene monomers and isoprene monomers for polymerization reaction, adjusting the modulus state of acrylic colloid, i.e. the obtained polymer; thereby preparing a tape with low modulus and good cohesion (high cohesion characteristics).

[0029] In some more preferred embodiments, the preparation method includes: first, introducing an inert gas into a hard acrylic monomer, a soft acrylic monomer, a functional acrylic monomer, a styrene monomer, an isoprene monomer and a first solvent, heating, mixing, stirring and heating to a first temperature, adding an initiator, and then heating to a second temperature for polymerization reaction, and then adding an inhibitor to obtain an acrylic pressure-sensitive adhesive polymer.

[0030] Furthermore, the mixing and stirring time is 1 to 2 hours.

[0031] Furthermore, the first temperature is 40-60°C.

[0032] Furthermore, the initiator is added dropwise within 10 to 30 minutes.

[0033] In some more preferred embodiments, the second temperature is 80-90°C.

[0034] In some more preferred embodiments, the polymerization reaction time is 3 to 5 hours.

[0035] In some more preferred embodiments, the mass ratio of the hard acrylic monomer, the soft acrylic monomer, the functional acrylic monomer, the styrene monomer, the isoprene monomer, the initiator, the inhibitor and the solvent is (5-15): (20-40): (1-3): (3-5): (10-15): (0.5-2): (1-3): (50-150).

[0036] The specific types of the hard acrylic monomer, soft acrylic monomer and functional acrylic monomer are as described above and will not be described in detail here.

[0037] Further, the initiator may include any one or a combination of two or more of benzoyl peroxide, azobisisobutyronitrile, lauroyl peroxide, tert-butyl perbenzoate, and benzoyl peroxide, but is not limited thereto.

[0038] Furthermore, the polymerization inhibitor may include at least any one of a hindered phenol antioxidant, a phosphite antioxidant, etc., but is not limited thereto.

[0039] Further, the first solvent may include any one or a combination of two or more of ethyl acetate, toluene, butanone, butyl acetate, methyl isobutyl ketone, acetone, xylene, n-heptane, cyclohexane, etc., but is not limited thereto.

[0040] Among them, as one of the more specific embodiments, a method for preparing an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion may specifically include the following steps: Calculated by mass percentage, the raw material components include: 5-15 parts of hard acrylic monomer, 20-40 parts of soft acrylic monomer, 1-3 parts of functional acrylic monomer, 3-5 parts of styrene monomer, 10-15 parts of isoprene monomer, 0.5-2 parts of initiator, 1-3 parts of inhibitor and 50-150 parts of solvent; First, hard acrylic monomer, soft acrylic monomer, functional acrylic monomer, styrene monomer, isoprene monomer and the first solvent are uniformly mixed, heated, mixed, stirred and nitrogen is passed for about 1 to 2 hours. When the temperature of the container is raised and stabilized between 80 and 85° C., the initiator is added dropwise and the addition is completed within 10 to 30 minutes, so that the reaction is more complete and uniform. The whole is kept warm for 3 to 5 hours under the conditions of water bath heating and nitrogen passing. After the reaction is completed, an inhibitor is added to terminate the reaction and cooling is started to finally obtain the required acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion.

[0041] As one aspect of the technical solution of the present invention, it involves an acrylic pressure-sensitive adhesive polymer, which is prepared by the above-mentioned preparation method.

[0042] Furthermore, another aspect of the embodiments of the present invention provides a method for preparing an acrylic adhesive, which comprises: uniformly mixing the acrylic pressure-sensitive adhesive polymer with a tackifying resin, an antioxidant, a curing agent, and a second solvent to prepare the acrylic adhesive.

[0043] In a more specific embodiment, the tackifying resin includes a combination of esterified rosin resin, terpene phenol resin and liquid rosin resin, but is not limited thereto. The present invention adopts a variety of resin combinations when preparing acrylic adhesives, which can significantly improve the bonding strength of the product. The tackifying resin of the present invention mainly plays a role in improving the bonding effect of colloids. Different types of resin combinations can balance the physical properties of colloids, enrich the bonding diversity of colloids, and make the bonding application of colloids more extensive and comprehensive.

[0044] In a more specific embodiment, the curing agent includes a combination of an isocyanate curing agent and an epoxy curing agent. The present invention uses a composite curing agent type heat curing cross-linking reaction system when preparing acrylic adhesives, which can significantly improve the colloid bonding strength and temperature resistance.

[0045] Furthermore, the curing agent can be any one or a combination of two or more of toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, hexamethylene diisocyanate, epoxy curing agent, 4,4'-diaminodiphenylmethane, 4,4'-bis-sec-butylaminodiphenylmethane, aluminum acetylacetonate, etc., but is not limited thereto.

[0046] Furthermore, the antioxidant may be any one of antioxidant 1010, antioxidant 1076, etc., or a combination of two thereof, but is not limited thereto.

[0047] Furthermore, the second solvent may be any one or a combination of two or more of ethyl acetate, toluene, butanone, butyl acetate, methyl isobutyl ketone, acetone, xylene, n-heptane, cyclohexane, etc., but is not limited thereto.

[0048] In a more specific embodiment, the mass ratio of the acrylic pressure-sensitive adhesive polymer, esterified rosin resin, terpene phenol resin, liquid rosin resin, antioxidant, isocyanate curing agent, epoxy curing agent and second solvent is 100: (5-10): (5-10): (1-3): (0.2-0.5): (0.5-1.5): (0.1-0.5): (30-80).

[0049] Among them, as one of the more specific implementation schemes, a method for preparing an acrylic adhesive can specifically include the following steps: preparing 100 parts of an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 5-10 parts of an esterified rosin resin, 5-10 parts of a terpene phenol resin, 1-3 parts of a liquid rosin resin, 0.2-0.5 parts of an antioxidant, 0.5-1.5 parts of an isocyanate curing agent, 0.1-0.5 parts of an epoxy curing agent and 30-80 parts of a second solvent, and mixing and stirring the above-mentioned acrylic pressure-sensitive adhesive polymer, tackifying resin, antioxidant, curing agent and second solvent to obtain the desired acrylic adhesive with low modulus and good cohesion.

[0050] Another aspect of the embodiments of the present invention further provides an acrylic adhesive prepared by the above preparation method.

[0051] Correspondingly, another aspect of an embodiment of the present invention further provides a method for preparing a low modulus and high cohesion tape, which comprises: applying the acrylic adhesive to at least one surface of a substrate, and drying to obtain the low modulus and high cohesion tape.

[0052] Furthermore, the preparation method comprises: coating the acrylic adhesive on the surface of a substrate.

[0053] Furthermore, the substrate includes a PET substrate, but is not limited thereto.

[0054] Furthermore, the drying temperature is 90-120° C. and the drying time is 2-4 min.

[0055] In a more specific embodiment, the preparation method includes: drying the solvent in an oven by transfer coating with a release film, coating the obtained acrylic adhesive on both sides or one side of a PET substrate, and drying the solvent in the adhesive by baking in an oven at 90-120°C / 2-4min to obtain a low modulus and high cohesion tape.

[0056] Correspondingly, another aspect of the embodiments of the present invention further provides a low modulus and high cohesion adhesive tape prepared by the aforementioned preparation method.

[0057] Furthermore, another aspect of the embodiments of the present invention provides the use of the low modulus and high cohesion tape in the preparation of electronic products (such as display modules).

[0058] In summary, the present invention adopts thermal polymerization technology, and by introducing styrene and isoprene monomers into the reaction system for polymerization, the molecular strength of the polymer can be significantly improved and the problem of excessive modulus of the polymer can be effectively controlled, so that the polymer has the characteristics of high strength and low modulus, thereby preparing a tape with low modulus and high cohesion properties, which is more suitable for the application requirements of thin, narrow and long in large-size electronic products.

[0059] The technical scheme of the present invention is further described below in conjunction with several embodiments, but the present invention is not limited to the scope of the embodiments. The reagents and raw materials used in the following examples are all commercially available, and the test methods without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturers.

[0060] Comparative Example 1 Use a harder, thin-coat, high-viscosity acrylic glue available on the market, and prepare the glue according to the ratio recommended by the manufacturer; apply it on a 50µm release film at a thickness of 44µm, bake and dry it at 100°C / 3min, stick it to both sides of a 12µm PET substrate, and mature it at room temperature for 7 days, 40°C for 3 days, or 50°C for 2 days to obtain the sample of Comparative Example 1.

[0061] Comparative Example 2 Use a softer, thin-coat, high-viscosity acrylic glue available on the market, and prepare the glue according to the ratio recommended by the manufacturer; apply it on a 50µm release film at a thickness of 44µm, bake and dry it at 100℃ / 3min, stick it to both sides of a 12µm PET substrate, and mature it at room temperature for 7 days, at 40℃ for three days, or at 50℃ for two days, to obtain the sample of Comparative Example 2.

[0062] Comparative Example 3 1. Preparation of acrylic pressure-sensitive adhesive polymer of Comparative Example 3: 10g of methyl methacrylate, 35g of n-butyl acrylate, 1.5g of maleic anhydride, 3g of styrene, 50g of butyl acetate, 30g of methyl isobutyl ketone, and 0.55g of benzoyl peroxide (BPO) as a thermal reaction initiator are mixed and reacted, and then 1g of a polymerization inhibitor is added and mixed evenly; after cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained; 2. Configuration of the acrylic adhesive of Comparative Example 3: 100g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.0g of isocyanate curing agent L-75, 0.3g of epoxy curing agent Y-202, 5g of esterified rosin, 7g of terpene phenol resin, 2g of liquid rosin resin, 70g of ethyl acetate, and 0.3g of antioxidant (1010), after the above substances are stirred evenly, an acrylic adhesive with low modulus and good cohesion can be obtained; 3. Preparation of the acrylic tape of Comparative Example 3: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0063] Comparative Example 4 1. Preparation of acrylic pressure-sensitive adhesive polymer of Comparative Example 4: 10g of methyl methacrylate, 35g of n-butyl acrylate, 1.5g of maleic anhydride, 12g of isoprene, 50g of butyl acetate, 30g of methyl isobutyl ketone, and 0.55g of benzoyl peroxide (BPO) as a thermal reaction initiator are mixed and reacted, and 1g of a polymerization inhibitor is added and mixed evenly; after cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained; 2. Configuration of the acrylic adhesive of Comparative Example 4: 100g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.0g of isocyanate curing agent L-75, 0.3g of epoxy curing agent Y-202, 5g of esterified rosin, 7g of terpene phenol resin, 2g of liquid rosin resin, 70g of ethyl acetate, and 0.3g of antioxidant (1010), after the above substances are stirred evenly, an acrylic adhesive with low modulus and good cohesion can be obtained; 3. Preparation of the acrylic tape of Comparative Example 4: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0064] Example 1 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 10g of methyl methacrylate, 35g of n-butyl acrylate, 1.5g of maleic anhydride, 3g of styrene, 12g of isoprene, 50g of butyl acetate and 30g of methyl isobutyl ketone are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 1h. When the temperature of the container is raised and stabilized at 40°C, 0.55g of heating reaction initiator benzoyl peroxide (BPO) is added dropwise within 20min. The whole is heated to 80°C under the condition of water bath heating and nitrogen introduction and kept warm for 5h. After the reaction is completed, 1g of hindered phenol antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 0.5g of isocyanate curing agent L-75, 0.5g of epoxy curing agent Y-202, 5g of esterified rosin, 7g of terpene phenol resin, 2g of liquid rosin resin, 70g of ethyl acetate, and 0.3g of antioxidant (1010), after the above substances are stirred evenly, an acrylic adhesive with low modulus and good cohesion can be obtained; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0065] Example 2 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 8g of methyl acrylate, 40g of ethyl acrylate, 2g of hydroxyethyl acrylate, 4g of styrene, 10g of isoprene, 45g of ethyl acetate and 25g of butanone are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 2h. When the temperature of the container is raised and stabilized at 50°C, 1.2g of azobisisobutyronitrile as a heating reaction initiator is added dropwise within 10min. The whole is heated to 85°C under the condition of water bath heating and nitrogen introduction and kept warm for 4h. After the reaction is completed, 1.5g of hindered phenol antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100 g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 0.8 g of isocyanate curing agent, 0.2 g of epoxy curing agent, 6 g of esterified rosin, 7 g of terpene phenol resin, 2 g of liquid rosin resin, 50 g of butyl acetate, and 0.5 g of antioxidant (1076), after the above substances are stirred evenly, an acrylic adhesive with low modulus and good cohesion can be obtained; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0066] Example 3 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 6g of vinyl acetate, 25g of n-octyl acrylate, 1g of hydroxyethyl methacrylate, 5g of styrene, 14g of isoprene, 40g of ethyl acetate and 30g of toluene are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 2h. When the temperature of the container is raised and stabilized at 60°C, 1.5g of lauroyl peroxide as a heating reaction initiator is added dropwise within 20min. The whole is heated to 90°C under the condition of water bath heating and nitrogen introduction and kept warm for reaction for 3h. After the reaction is completed, 2.0g of hindered phenol antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100 g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.2 g of isocyanate curing agent, 0.2 g of epoxy curing agent, 6 g of esterified rosin, 7 g of terpene phenol resin, 2 g of liquid rosin resin, 50 g of toluene, and 0.4 g of antioxidant (1076), after the above substances are stirred evenly, an acrylic adhesive with low modulus and good cohesion can be obtained; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0067] Example 4 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 6g of isobornyl methacrylate, 25g of butyl acrylate, 1g of acrylic acid, 5g of styrene, 14g of isoprene, 40g of ethyl acetate and 30g of toluene are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 2h. When the temperature of the container is raised and stabilized at 60°C, 1.0g of tert-butyl peroxybenzoate as a heating reaction initiator is added dropwise within 30min. The whole is heated to 90°C under the condition of water bath heating and nitrogen introduction and kept warm for 4h. After the reaction is completed, 1.5g of hindered phenol antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100 g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.5 g of isocyanate curing agent, 0.5 g of epoxy curing agent, 8 g of esterified rosin, 8 g of terpene phenol resin, 3 g of liquid rosin resin, 45 g of methyl isobutyl ketone, and 0.35 g of antioxidant (1076), after mixing the above substances evenly, an acrylic adhesive with low modulus and good cohesion can be obtained; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0068] Example 5 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 9g of methyl acrylate, 36g of n-hexyl acrylate, 2g of itaconic acid, 5g of styrene, 15g of isoprene, 30g of toluene and 50g of butanone are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 2h. When the temperature of the container is raised and stabilized at 60°C, 1.8g of benzoyl peroxide as a heating reaction initiator is added dropwise within 15min. The whole is heated to 80°C under the condition of water bath heating and nitrogen introduction and kept warm for 4h. After the reaction is completed, 1.5g of hindered phenol antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100 g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.5 g of isocyanate curing agent, 0.5 g of epoxy curing agent, 8 g of esterified rosin, 8 g of terpene phenol resin, 3 g of liquid rosin resin, 45 g of n-heptane, and 0.35 g of antioxidant (1076), and the above substances are stirred evenly to obtain acrylic adhesive with low modulus and good cohesion; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it at 100℃ / 3min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0069] Example 6 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 5g of acrylonitrile, 20g of n-pentyl acrylate, 3g of hydroxypropyl acrylate, 4g of styrene, 15g of isoprene, 30g of xylene and 20g of acetone are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 2h. When the temperature of the container is raised and stabilized at 50°C, 0.5g of benzoyl peroxide as a heating reaction initiator is added dropwise within 20min. The whole is heated to 85°C under the condition of water bath heating and nitrogen introduction and kept warm for 5h. After the reaction is completed, 1.5g of phosphite antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.0g of isocyanate curing agent, 0.1g of epoxy curing agent, 10g of esterified rosin, 10g of terpene phenol resin, 1g of liquid rosin resin, 30g of ethyl acetate, and 0.2g of antioxidant (1076), stir the above substances evenly to obtain acrylic adhesive with low modulus and good cohesion; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it by baking at 90℃ / 4min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0070] Example 7 1. Preparation of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion: First, 15g of acrylamide, 35g of lauryl acrylate, 3g of hydroxypropyl methacrylate, 4g of styrene, 12g of isoprene, 70g of cyclohexane and 80g of ethyl acetate are mixed evenly, heated, mixed and stirred and nitrogen is introduced for 2h. When the temperature of the container is raised and stabilized at 40°C, 2g of benzoyl peroxide as a heating reaction initiator is added dropwise within 30min. The whole is heated to 80°C under the condition of water bath heating and nitrogen introduction and kept warm for 4h. After the reaction is completed, 3g of phosphite antioxidant (inhibitor) is added and mixed evenly. After cooling, an acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion is obtained. 2. Configuration of acrylic adhesive with low modulus and good cohesion: 100 g of acrylic pressure-sensitive adhesive polymer with low modulus and good cohesion, 1.0 g of isocyanate curing agent, 0.1 g of epoxy curing agent, 5 g of esterified rosin, 5 g of terpene phenol resin, 1 g of liquid rosin resin, 80 g of ethyl acetate, and 0.3 g of antioxidant (1076), and the above substances are stirred evenly to obtain acrylic adhesive with low modulus and good cohesion; 3. Preparation of acrylic tape with low modulus and good cohesion: Coat it on a 50µm release film at a thickness of 44µm, dry it by baking at 120℃ / 2min, stick it on both sides of a 12µm PET substrate, and age it at room temperature for 7 days, 40℃ for three days, or 50℃ for two days to obtain an acrylic tape with low modulus and good cohesion.

[0071] The inventors of this case conducted the following performance tests on the adhesive tapes in Examples 1 to 5 and Comparative Examples 1 to 4: 1) Peel force test: The tested tape sample needs to be left standing for more than 24 hours at 23±1℃ and 50±5%RH; cut the tape sample into 25mm*200mm test strips (the non-test adhesive surface of the double-sided tape is reinforced with 50μmPET); wipe the SUS plate for testing clean with alcohol (the size is about 50mm*150mm*2mm); stick the test strip on the SUS; use a 2k roller to manually roll back and forth three times at a speed of about 300mm / min; after rolling, put it in the sample holder and let it stand at room temperature for 20 minutes; after standing, pull the tape and SUS apart at an angle of 180° and a speed of 300mm / min on the tensile testing machine, and record the force value displayed on the tensile testing machine, unit: N / 25mm.

[0072] 2) Holding force test: The double-sided tape sample to be tested needs to be left standing for more than 24 hours at 23±1℃ and 50±5%RH; cut the sample into 100mm*25mm (the non-test adhesive surface of the double-sided tape is reinforced with 50μmPET); wipe the PC board for testing (size is about 75mm*50mm*2mm) with alcohol, let it stand for 30 minutes, and wipe it with a clean dust-free cloth before use. Peel off the release film on one side of the sample and attach it to the end of the SUS board to be tested with a small roller, with a bonding area of ​​25mm*25mm; after the bonding is completed, use 2k rollers to manually roll back and forth three times at a speed of about 300mm / min; after the sample is made, let it stand at room temperature for more than 24 hours to achieve full bonding; after the standing is completed, hang the sample in a high-temperature and high-humidity holding force oven and hang a 1k weight at the lower end to start the test; record the sample drop time or record the sliding displacement of the tape on the test board after 24 hours. (Unit: H or mm).

[0073] 3) Modulus test: The double-sided tape samples to be tested need to be left to stand for more than 24 hours at 23±1℃ and 50±5%RH. After the release film is removed from the samples, the samples are stacked to a thickness of 800um. On the Anton Paar equipment, the rheological data of the test samples are designed according to the parameters of temperature range -30℃ to 130℃, test frequency 1HZ, and test heating rate 2k / min. The storage modulus of the material at -20℃ and 65℃ is recorded.

[0074] The above test results are shown in Table 1: Table 1 Test results of adhesive tape properties in Examples 1 to 5 and Comparative Examples 1 to 4

[0075] From the above data analysis, the modulus of the comparative samples is either high or low at low temperatures, and the modulus is relatively low at high temperatures, which also leads to poor performance of the comparative tape in the high temperature and high humidity retention test, and it is difficult to ensure the dimensional stability required in the weathering test. The samples shown in the embodiment are improved samples after the introduction of styrene and isoprene monomers in the synthesis of acrylic glue. After the improvement, the modulus distribution state of the colloid can be effectively improved, so that the colloid has a low modulus and is softer at low temperatures, and has better adhesion; the modulus is high at high temperatures, so that the colloid has a higher cohesion and has a good high temperature and high humidity retention effect, which greatly improves the dimensional stability of the tape product in the harsh weathering test of electronic products.

[0076] In summary, the present invention introduces styrene monomers and isoprene monomers into acrylic polymers to regulate the modulus state of the polymer, thereby preparing a tape with low modulus and high cohesion properties to meet the needs of tape applications in the current and future markets for dimensional stability of narrow and long, conformable plastic materials in rigorous weathering tests.

[0077] In addition, the inventors of this case also conducted experiments with other raw materials and conditions listed in this specification with reference to the aforementioned embodiments, and obtained similar results.

[0078] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An acrylic pressure-sensitive adhesive polymer, characterized in that: It is prepared by polymerization of acrylic monomers, styrene monomers and isoprene monomers.

2. The acrylic pressure-sensitive adhesive polymer according to claim 1, characterized in that: The acrylic monomers include a combination of hard acrylic monomers, soft acrylic monomers and functional acrylic monomers; preferably, the hard acrylic monomers include any one or a combination of two or more of methyl methacrylate, methyl acrylate, vinyl acetate, isobornyl methacrylate, acrylonitrile and acrylamide; preferably, the soft acrylic monomers include any one or a combination of two or more of n-butyl acrylate, ethyl acrylate, n-octyl acrylate, butyl acrylate, n-hexyl acrylate, n-pentyl acrylate, n-heptyl acrylate, isooctyl acrylate, isooctyl methacrylate, n-nonyl acrylate and lauryl acrylate; preferably, the functional acrylic monomers include any one or a combination of two or more of maleic anhydride, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylic acid, itaconic acid, maleic anhydride, methacrylic acid, hydroxypropyl acrylate and hydroxypropyl methacrylate; Preferably, the raw materials for preparing the acrylic pressure-sensitive adhesive polymer include the following components: hard acrylic monomer, soft acrylic monomer, functional acrylic monomer, styrene monomer, isoprene monomer, initiator, inhibitor and solvent; Particularly preferably, the raw materials for preparing the acrylic pressure-sensitive adhesive polymer include the following components, calculated by mass percentage: 5 to 15 parts of hard acrylic monomers, 20 to 40 parts of soft acrylic monomers, 1 to 3 parts of functional acrylic monomers, 3 to 5 parts of styrene monomers, 10 to 15 parts of isoprene monomers, 0.5 to 2 parts of initiators, 1 to 3 parts of inhibitors, and 50 to 150 parts of solvents.

3. A method for preparing an acrylic pressure-sensitive adhesive polymer, characterized in that: include: A reaction system comprising a hard acrylic monomer, a soft acrylic monomer, a functional acrylic monomer, a styrene monomer, an isoprene monomer, an initiator, a polymerization inhibitor and a first solvent is polymerized to obtain an acrylic pressure-sensitive adhesive polymer.

4. The preparation method according to claim 3, characterized in that: include: First, hard acrylic monomer, soft acrylic monomer, functional acrylic monomer, styrene monomer, isoprene monomer and a first solvent are introduced with an inert gas, heated, mixed and stirred and heated to a first temperature, an initiator is added, and then the temperature is raised to a second temperature for polymerization reaction, and then a polymerization inhibitor is added to obtain an acrylic pressure-sensitive adhesive polymer; Preferably, the mixing time is 1 to 2 hours; Preferably, the first temperature is 40-60°C; Preferably, the initiator is added dropwise within 10 to 30 minutes; Preferably, the second temperature is 80-90°C; Preferably, the polymerization reaction time is 3 to 5 hours; And / or, the mass ratio of the hard acrylic monomer, the soft acrylic monomer, the functional acrylic monomer, the styrene monomer, the isoprene monomer, the initiator, the inhibitor and the solvent is (5-15): (20-40): (1-3): (3-5): (10-15): (0.5-2): (1-3): (50-150); And / or, the hard acrylic monomer includes any one or a combination of two or more of methyl methacrylate, methyl acrylate, vinyl acetate, isobornyl methacrylate, acrylonitrile, and acrylamide; And / or, the soft acrylic monomer includes any one or a combination of two or more of n-butyl acrylate, ethyl acrylate, n-octyl acrylate, butyl acrylate, n-hexyl acrylate, n-pentyl acrylate, n-heptyl acrylate, isooctyl acrylate, isooctyl methacrylate, n-nonyl acrylate, and lauryl acrylate; And / or, the functional acrylic monomer includes any one or a combination of two or more of maleic anhydride, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylic acid, itaconic acid, methacrylic acid, hydroxypropyl acrylate, and hydroxypropyl methacrylate; And / or, the initiator includes any one of benzoyl peroxide, azobisisobutyronitrile, lauroyl peroxide, tert-butyl perbenzoate, benzoyl peroxide, or a combination of two or more thereof; and / or, the inhibitor includes a hindered phenol antioxidant and / or a phosphite antioxidant; and / or, the first solvent includes any one of ethyl acetate, toluene, butanone, butyl acetate, methyl isobutyl ketone, acetone, xylene, n-heptane, or a combination of two or more thereof.

5. An acrylic pressure-sensitive adhesive polymer prepared by the preparation method according to any one of claims 3 to 4.

6. A method for preparing an acrylic adhesive, characterized in that: include: The acrylic pressure-sensitive adhesive polymer according to any one of claims 1 to 2 and 5 is uniformly mixed with a tackifying resin, an antioxidant, a curing agent, and a second solvent to prepare an acrylic adhesive; Preferably, the tackifying resin comprises a combination of esterified rosin resin, terpene phenol resin and liquid rosin resin; Preferably, the curing agent includes a combination of an isocyanate curing agent and an epoxy curing agent, and particularly preferably, the curing agent includes any one or a combination of two or more of toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, hexamethylene diisocyanate, 4,4'-diaminodiphenylmethane, 4,4'-bis-sec-butylaminodiphenylmethane, and aluminum acetylacetonate; Preferably, the antioxidant includes any one of antioxidant 1010 and antioxidant 1076 or a combination of two thereof; preferably, the second solvent includes any one of ethyl acetate, toluene, butanone, butyl acetate, methyl isobutyl ketone, acetone, xylene, n-heptane, and cyclohexane or a combination of two or more thereof; Preferably, the mass ratio of the acrylic pressure-sensitive adhesive polymer, esterified rosin resin, terpene phenol resin, liquid rosin resin, antioxidant, isocyanate curing agent, epoxy curing agent and the second solvent is 100: (5-10): (5-10): (1-3): (0.2-0.5): (0.5-1.5): (0.1-0.5): (30-80).

7. The acrylic adhesive prepared by the preparation method according to claim 6.

8. A method for preparing a low modulus and high cohesion adhesive tape, characterized in that: include: Applying the acrylic adhesive of claim 7 to at least one surface of a substrate and drying it to obtain a low modulus and high cohesion tape; Preferably, the preparation method comprises: coating the acrylic adhesive on the surface of a substrate; Preferably, the substrate comprises a PET substrate; Preferably, the drying temperature is 90-120° C. and the drying time is 2-4 min.

9. The low modulus and high cohesion adhesive tape prepared by the preparation method of claim 8, wherein preferably, at -20°C, the storage modulus of the adhesive tape is below 130 MPa; at 65°C, the storage modulus of the adhesive tape is above 0.05 MPa; Preferably, the adhesive tape is kept in a 65°C / 90%RH environment for more than 24 hours.

10. Use of the low modulus and high cohesion adhesive tape according to claim 9 in the preparation of electronic products, preferably, the electronic product comprises a display module.

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