Hyperbranched polyacrylate adhesive, preparation method and PI adhesive tape

Abstract

The invention provides a hyperbranched polyacrylate adhesive, a preparation method and a PI adhesive tape, and belongs to the technical field of adhesives. According to the invention, branched polyamine is introduced by utilizing the branched phenolic polyamine acrylic acid modified monomer, and the hyperbranched polymer with unit mass has an extremely large surface area, so that the contact and interaction with an adhered object are enhanced, and the bonding strength and wettability of the adhesive are improved; according to the invention, the branched phenolic polyamine acrylic acid modified monomer and the acrylate are polymerized, so that the temperature resistance of the acrylate is improved, the phenolic skeleton is introduced, the internal stress caused by heat shrinkage at high temperature is solved, and the special structure of the hyperbranched polymer enables the hyperbranched polymer to maintain good dimensional stability and chemical stability at high temperature. Therefore, the hyperbranched polyacrylate adhesive provided by the invention not only keeps the bonding effect of an acrylic pressure-sensitive adhesive, but also improves the temperature resistance of a cured product by introducing the branched phenolic polyamine through modification.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to a hyperbranched polyacrylate adhesive and a preparation method thereof, and a PI tape. Background Art

[0002] Polyimide tape, also known as PI tape and brown high-temperature tape, is based on polyimide film (PI) and coated with imported silicone pressure-sensitive adhesive or modified acrylic adhesive. It has high and low temperature resistance, acid and alkali resistance, solvent resistance, electrical insulation (H grade), radiation protection and other properties. It plays an important role in the preparation of the electrolyte layer, the preparation of the positive and negative electrodes, packaging and use, and can improve the stability, performance and safety of the battery. However, with the growth of demand in the new energy terminal market, higher requirements are placed on the performance of PI tapes, and the performance of existing PI tapes cannot meet the requirements. For example, Chinese patent CN202211273053.1 discloses a PI single-sided tape used for the protection of the pole ears of cylindrical lithium batteries. It uses electrolyte-resistant synthetic rubber glue, and has high bonding strength after being bonded at room temperature and soaked in electrolyte; it uses hydrogenated rosin resin and high softening point hydrogenated petroleum resin to improve heat resistance and anti-warping performance. However, the temperature resistance of the PI single-sided tape obtained by this method is poor. For another example, Chinese patent CN 202210213819.0 discloses a high temperature resistant PET-PI composite film and its adhesive tape. Although the heat resistance of this adhesive tape is improved, the bonding strength of the adhesive tape is poor.

[0003] Therefore, there is an urgent need to provide a polyacrylate adhesive with good adhesion and temperature resistance to improve the adhesion and temperature resistance of PI tape. Summary of the invention

[0004] The purpose of the present invention is to provide a hyperbranched polyacrylate adhesive and a preparation method thereof and a PI tape. The hyperbranched polyacrylate adhesive provided by the present invention has good adhesion and temperature resistance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a hyperbranched polyacrylate adhesive, which is obtained by polymerization reaction of raw materials including the following components in parts by mass:

[0007]

[0008]

[0009] The preparation method of the branched phenolic polyamine acrylic acid modified monomer comprises: mixing branched polyamine, phenol and formaldehyde, carrying out Mannich reaction to obtain branched phenolic polyamine; mixing the branched phenolic polyamine with acrylic acid, carrying out condensation reaction to obtain branched phenolic polyamine acrylic acid modified monomer.

[0010] Preferably, the soft monomer includes one or more of butyl acrylate, isooctyl acrylate and lauryl acrylate.

[0011] Preferably, the hard monomer includes one or more of vinyl acetate, acrylic acid, acrylamide, styrene, methyl acrylate and methyl methacrylate.

[0012] Preferably, the functional monomer includes one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, N-hydroxyacrylamide and ethyl methacrylate.

[0013] Preferably, the molar ratio of the branched polyamine, phenol and formaldehyde is 1:6:6.

[0014] Preferably, the temperature of the Mannich reaction is 25-50° C., and the time of the Mannich reaction is 3-6 hours.

[0015] Preferably, the molar ratio of the branched phenolic polyamine to acrylic acid is 1:2-8.

[0016] Preferably, the cross-linking agent includes one or more of isocyanates, amino resins, metal organic compounds and aziridines.

[0017] The present invention also provides a method for preparing the hyperbranched polyacrylate adhesive described in the above technical solution, comprising: mixing branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer, functional monomer, initiator and solvent, and performing polymerization reaction to obtain adhesive solution;

[0018] The glue solution is mixed with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

[0019] The present invention also provides a PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive described in the above technical solution or the hyperbranched polyacrylate adhesive prepared by the preparation method described in the technical solution.

[0020] The invention provides a hyperbranched polyacrylate adhesive, which is obtained by polymerization reaction of raw materials including the following components by mass: 60-80 parts of soft monomers, 10-20 parts of hard monomers, 1-5 parts of functional monomers, 10-20 parts of branched phenolic polyamine acrylic acid modified monomers, 0.5-1 parts of initiators, 0.5-2 parts of crosslinking agents and 50-70 parts of solvents; the preparation method of the branched phenolic polyamine acrylic acid modified monomer comprises: mixing branched polyamine, phenol and formaldehyde, carrying out Mannich reaction to obtain branched phenolic polyamine; mixing the branched phenolic polyamine with acrylic acid, carrying out condensation reaction to obtain the branched phenolic polyamine acrylic acid modified monomer. The present invention first prepares a branched phenolic polyamine acrylic acid modified monomer with a double bond structure; the branched phenolic polyamine acrylic acid modified monomer introduces a branched polyamine, and the hyperbranched polymer per unit mass has a very large surface area, which is conducive to enhancing the contact and interaction with the adherend, and improving the bonding strength and wettability of the adhesive; the present invention utilizes the branched phenolic polyamine acrylic acid modified monomer and acrylate polymerization to improve the temperature resistance of acrylate, introduces a phenolic skeleton, solves the internal stress caused by thermal shrinkage at high temperature, and the special structure of the hyperbranched polymer enables it to still maintain good dimensional stability and chemical stability at high temperature. Therefore, the hyperbranched polyacrylate adhesive provided by the present invention not only maintains the bonding effect of acrylic pressure-sensitive adhesive, but also introduces branched phenolic polyamines through modification to improve the temperature resistance of the cured product. The results of the embodiments show that the hyperbranched polyacrylate adhesive provided by the present invention has a viscosity of 6000 to 10000 cps (GB / T20794-2013) at room temperature, a peel strength of 500 to 800 g in a 180° peel test (GB / T2790-1995), and no adhesive residue is left when the adhesive is torn off after being adhered to the glass for 2 hours at 180°C. DETAILED DESCRIPTION

[0021] The present invention provides a hyperbranched polyacrylate adhesive, which is obtained by polymerization reaction of raw materials including the following components in parts by mass:

[0022]

[0023] The preparation method of the branched phenolic polyamine acrylic acid modified monomer comprises: mixing branched polyamine, phenol and formaldehyde, carrying out Mannich reaction to obtain branched phenolic polyamine; mixing the branched phenolic polyamine with acrylic acid, carrying out condensation reaction to obtain branched phenolic polyamine acrylic acid modified monomer.

[0024] In the present invention, unless otherwise specified, the raw materials used in the present invention are all commercially available products well known to those skilled in the art.

[0025] The raw materials for preparing the hyperbranched polyacrylate adhesive include 60 to 80 parts of soft monomers, preferably 70 to 80 parts, by mass. In the present invention, the soft monomers preferably include one or more of butyl acrylate, isooctyl acrylate and lauryl acrylate, more preferably butyl acrylate and / or isooctyl acrylate. The present invention can make the hyperbranched polyacrylate adhesive have good adhesion and softness by using soft monomers.

[0026] The raw materials for preparing the hyperbranched polyacrylate adhesive of the present invention include 10 to 20 parts of hard monomers, preferably 10 to 15 parts, based on 60 to 80 parts by mass of soft monomers. In the present invention, the hard monomers preferably include one or more of vinyl acetate, acrylic acid, acrylamide, styrene, methyl acrylate and methyl methacrylate, more preferably one or more of vinyl acetate, acrylic acid, acrylamide and styrene. The hard monomers used in the present invention can improve the cohesion, strength and adhesion of the hyperbranched polyacrylate adhesive.

[0027] Based on 60 to 80 parts by mass of the soft monomer, the raw materials for preparing the hyperbranched polyacrylate adhesive of the present invention include 1 to 5 parts of functional monomers, preferably 1.5 to 3 parts. In the present invention, the functional monomers preferably include one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, N-hydroxyacrylamide and ethyl methacrylate, more preferably one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate. By adding functional monomers, the present invention can give polyacrylate flexibility, hardness and adhesion.

[0028] The raw materials for preparing the hyperbranched polyacrylate adhesive of the present invention include 5 to 20 parts of branched phenolic polyamine acrylic acid modified monomers, preferably 10 to 20 parts, based on 60 to 80 parts by mass of the soft monomer. The present invention utilizes branched phenolic polyamine acrylic acid modified monomers with double bond structures, which have a large surface area, are conducive to enhancing contact and interaction with adherends, improve the bonding strength and wettability of the adhesive, and can introduce a phenolic skeleton to solve the internal stress caused by thermal shrinkage at high temperatures. The special structure of the hyperbranched polymer enables it to maintain good dimensional stability and chemical stability at high temperatures.

[0029] In the present invention, the preparation method of the branched phenolic polyamine acrylic acid modified monomer comprises: mixing branched polyamine, phenol and formaldehyde, and performing Mannich reaction to obtain branched phenolic polyamine; mixing the branched phenolic polyamine with acrylic acid, and performing condensation reaction to obtain branched phenolic polyamine acrylic acid modified monomer.

[0030] The invention mixes branched polyamine, phenol and formaldehyde, and performs Mannich reaction to obtain branched phenolic polyamine.

[0031] The present invention has no particular limitation on the source and synthesis method of the branched polyamine, and any conventional branched polyamine may be used. In an embodiment of the present invention, the structural formula of the branched polyamine may be specifically shown in formula (I):

[0032]

[0033] In the present invention, the synthesis method of the branched polyamine shown in formula (I) preferably comprises: mixing triethylenetetramine, methyl acrylate and methanol, performing an addition reaction to obtain an intermediate solution; mixing the intermediate solution with ethylenediamine, performing an acylation reaction to obtain the branched polyamine.

[0034] In the present invention, triethylenetetramine, methyl acrylate and methanol are preferably mixed to carry out an addition reaction to obtain an intermediate solution.

[0035] In the present invention, the methanol is used as a catalyst and a solvent. The present invention does not impose any particular limitation on the amount of the methanol used, as long as the amount can fully dissolve triethylenetetramine and methyl acrylate.

[0036] In the present invention, the temperature of the addition reaction is preferably 25° C., and the time of the addition reaction is preferably 24 h.

[0037] After obtaining the intermediate, the present invention preferably mixes the intermediate solution with ethylenediamine to carry out an acylation reaction to obtain a branched polyamine.

[0038] In an embodiment of the present invention, the molar ratio of triethylenetetramine, methyl acrylate and ethylenediamine may be specifically 1:6:6.

[0039] In the present invention, the temperature of the acylation reaction is preferably 25° C., and the time of the acylation reaction is preferably 48 h.

[0040] In an embodiment of the present invention, the synthesis route of the branched polyamine can be specifically as shown in formula (II):

[0041]

[0042] The invention adopts branched polyamine to make the hyperbranched polymer have a very large surface area per unit mass, which is beneficial to enhance the contact and interaction with the adherend and improve the bonding strength and wettability of the adhesive.

[0043] In the present invention, the molar ratio of the branched polyamine, phenol and formaldehyde is preferably 1:6:6. By controlling the molar ratio of the branched polyamine, phenol and formaldehyde within the above range, the components can be fully reacted to obtain branched phenolic polyamine.

[0044] The present invention has no particular limitation on the method for mixing the branched polyamine, phenol and formaldehyde, and a conventional mixing method can be used to uniformly mix the components. In the present invention, the method for mixing the branched polyamine, phenol and formaldehyde is preferably stirring.

[0045] The present invention preferably adjusts the pH value of the mixed solution when the branched polyamine, phenol and formaldehyde are mixed, and then performs the Mannich reaction. In the present invention, the pH value is preferably 3 to 6, and more preferably 5 to 6. The present invention controls the pH value of the mixed solution of the branched polyamine, phenol and formaldehyde within the above range, which is more conducive to promoting the full progress of the Mannich reaction.

[0046] In the present invention, the temperature of the Mannich reaction is preferably 25 to 50° C., more preferably 35 to 40° C.; the time of the Mannich reaction is preferably 3 to 6 hours, more preferably 3 to 5 hours. The present invention controls the temperature and time within the above ranges, which can promote the full progress of the Mannich reaction.

[0047] The present invention preferably dries the product of the Mannich reaction to obtain branched phenolic polyamine. The present invention has no particular limitation on the drying temperature and method, and conventional temperature and drying method can be used to fully dry the product of the Mannich reaction.

[0048] After the branched phenolic polyamine is obtained, the present invention mixes the branched phenolic polyamine with acrylic acid to carry out a condensation reaction to obtain a branched phenolic polyamine acrylic acid-modified monomer.

[0049] In the present invention, the molar ratio of the branched phenolic polyamine to acrylic acid is preferably 1:2 to 8, more preferably 1:5 to 6. The present invention controls the molar ratio of the branched phenolic polyamine to acrylic acid within the above range, so that the two can react fully to obtain a branched phenolic polyamine acrylic acid modified monomer.

[0050] The present invention has no particular limitation on the method of mixing the branched phenolic polyamine and acrylic acid, and a conventional mixing method can be used to uniformly mix the two. In the present invention, the mixing method is preferably stirring.

[0051] In the present invention, the temperature of the condensation reaction is preferably 70-90°C, more preferably 80-85°C; the time of the condensation reaction is preferably 6-8h, more preferably 6-7h. The present invention is more conducive to promoting a more complete condensation reaction by controlling the temperature and time within the above ranges.

[0052] The present invention preferably dries the product of the condensation reaction to obtain a branched phenolic polyamine acrylic acid modified monomer. The present invention has no particular limitation on the temperature and method of the drying, and conventional temperature and drying method can be used to fully dry the product of the condensation reaction.

[0053] In one embodiment of the present invention, the reaction principle for preparing the branched phenolic polyamine acrylic acid modified monomer is as shown in formula (III):

[0054]

[0055] Based on 60 to 80 parts by mass of the soft monomer, the raw materials for preparing the hyperbranched polyacrylate adhesive of the present invention include 0.5 to 1 part of initiator, preferably 0.5 to 0.8 part. In the present invention, the initiator preferably includes one or more of dibenzoyl peroxide, azobisisobutyronitrile and azobisisoheptylonitrile, more preferably one or two of dibenzoyl oxide, azobisisobutyronitrile and azobisisoheptylonitrile. The present invention can initiate a polymerization reaction by adding an initiator.

[0056] The raw materials for preparing the hyperbranched polyacrylate adhesive of the present invention include 0.5 to 2 parts of a crosslinking agent, preferably 1 to 2 parts, based on 60 to 80 parts by mass of the soft monomer. In the present invention, the crosslinking agent preferably includes one or more of isocyanates, amino resins, metal organic compounds and aziridines, more preferably amino resins. By adding a crosslinking agent, the present invention can crosslink and cure the polymer emulsion.

[0057] Based on 60 to 80 parts by mass of the soft monomer, the raw materials for preparing the hyperbranched polyacrylate adhesive of the present invention include 50 to 70 parts of solvent, preferably 50 to 60 parts. In the present invention, the solvent preferably includes one or more of ethyl acetate, butanone, acetone, butyl acetate, toluene and xylene, more preferably ethyl acetate, butanone, acetone or toluene. The present invention utilizes the solvent to provide a suitable reaction environment for the polymerization reaction.

[0058] The invention first prepares a branched phenolic polyamine acrylic acid modified monomer with a double bond structure; the branched phenolic polyamine acrylic acid modified monomer introduces a branched polyamine, and a hyperbranched polymer per unit mass has a very large surface area, which is beneficial to enhancing the contact and interaction with the adherend and improving the bonding strength and wettability of the adhesive; the invention utilizes the branched phenolic polyamine acrylic acid modified monomer and acrylate polymerization to improve the temperature resistance of the acrylate, introduces a phenolic skeleton, solves the internal stress caused by thermal shrinkage at high temperature, and the special structure of the hyperbranched polymer enables it to maintain good dimensional stability and chemical stability at high temperature.

[0059] The present invention also provides a method for preparing the hyperbranched polyacrylate adhesive described in the above technical solution, comprising: mixing branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer, functional monomer, initiator and solvent, and performing polymerization reaction to obtain adhesive solution;

[0060] The glue solution is mixed with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

[0061] The invention mixes branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer, functional monomer, initiator and solvent, and performs polymerization reaction to obtain glue solution.

[0062] In the present invention, the method of mixing the branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer, functional monomer, initiator and solvent to carry out polymerization reaction preferably comprises the following steps:

[0063] (1) mixing a branched phenolic polyamine acrylic acid modified monomer, a soft monomer, a hard monomer and a functional monomer to obtain a monomer mixture;

[0064] (2) mixing an initiator and a solvent to obtain an initiator solution;

[0065] (3) mixing one-half of the monomer mixture obtained in step (1) with one-third of the initiator solution obtained in step (2), and performing a first polymerization reaction to obtain a first polymer solution;

[0066] (4) mixing the remaining part of the monomer mixture obtained in step (1) with one third of the initiator solution obtained in step (2), and then adding the mixture dropwise to the first polymer solution obtained in step (3) to carry out a second polymerization reaction to obtain a second polymer solution;

[0067] (5) mixing one third of the initiator solution obtained in step (2) with the second polymer solution obtained in step (4), and performing a third polymerization reaction to obtain a glue solution;

[0068] There is no chronological order between step (1) and step (2).

[0069] In the present invention, branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer and functional monomer are preferably mixed to obtain a monomer mixture.

[0070] The present invention has no particular limitation on the method of mixing the branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer and functional monomer, and conventional mixing methods can be used to uniformly mix the components. In the present invention, the mixing method is preferably stirring.

[0071] In the present invention, the initiator and the solvent are preferably mixed to obtain an initiator solution.

[0072] The present invention has no particular limitation on the method of mixing the initiator and the solvent, as long as the initiator can be completely dissolved in the solvent.

[0073] After obtaining the monomer mixture and the initiator solution, the present invention preferably mixes one-half of the monomer mixture with one-third of the initiator solution, and then conducts a first polymerization reaction to obtain a first polymer solution.

[0074] In the present invention, the method of mixing the half of the monomer mixture and the one-third of the initiator solution is preferably stirring. In the present invention, the temperature is preferably increased during the stirring process. In the present invention, the temperature endpoint of the heating is the temperature of the first polymerization reaction. In the present invention, by increasing the temperature during the mixing process, the product obtained by the polymerization reaction can be made more uniform.

[0075] In the present invention, the temperature of the first polymerization reaction is preferably 80-90°C, more preferably 85-90°C; the time of the first polymerization reaction is preferably 0.5-1h, more preferably 0.6-0.8h. The present invention is more conducive to promoting the polymerization reaction to proceed fully by controlling the temperature and time within the above ranges.

[0076] After obtaining the first polymer solution, the present invention preferably mixes the remaining part of the monomer mixture with one third of the initiator solution, and then drips the mixture into the first polymer solution to carry out a second polymerization reaction to obtain a second polymer solution.

[0077] The present invention has no special limitation on the method of mixing the remaining part of the monomer mixture with one third of the initiator solution, and a conventional mixing method can be used to mix the two uniformly. In an embodiment of the present invention, the mixing method is preferably to mix the remaining part of the monomer mixture with one third of the initiator solution in a constant pressure dropping funnel. After the two are mixed in the constant pressure dropping funnel, the mixed product can be added dropwise to the first polymer solution using the constant pressure dropping funnel.

[0078] The present invention adds the monomer mixture and the initiator solution by dropwise addition, so that the monomer mixture, the initiator solution and the first polymerization reaction are mixed more evenly during the dropwise addition, and the rate of the polymerization reaction is controlled to proceed slowly during the dropwise addition, thereby making the product obtained by the polymerization reaction more uniform. The present invention does not specifically limit the rate of the dropwise addition, and can be adjusted by a conventional dropwise addition method.

[0079] In the present invention, the temperature of the second polymerization reaction is preferably 80-90°C, more preferably 85-90°C; the time of the second polymerization reaction is preferably 4-6h, more preferably 5-6h. The present invention is more conducive to promoting the full progress of the second polymerization reaction by controlling the temperature and time within the above ranges.

[0080] After obtaining the second polymer solution, the present invention preferably mixes one third of the initiator solution with the second polymer solution to carry out a third polymerization reaction to obtain a glue solution.

[0081] The present invention has no particular limitation on the method for mixing the one-third of the initiator solution with the second polymer solution, and a conventional mixing method can be used to uniformly mix the two. In the present invention, the mixing method is preferably stirring.

[0082] In the present invention, the temperature of the third polymerization reaction is preferably 80-90°C, more preferably 85-90°C; the time of the third polymerization reaction is preferably 3-5h, more preferably 4-5h. The present invention is more conducive to promoting the third polymerization reaction to proceed fully by controlling the temperature and time within the above ranges.

[0083] The present invention preferably cools down after the third polymerization reaction to obtain a glue solution. The present invention is more conducive to controlling the discharging operation by cooling down. In an embodiment of the present invention, the terminal temperature of the cooling down can be specifically 50°C.

[0084] After obtaining the glue solution, the invention mixes the glue solution with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

[0085] The present invention has no particular limitation on the method for mixing the glue solution and the crosslinking agent, and a conventional mixing method can be used to uniformly mix the two. In the present invention, the mixing method is preferably stirring.

[0086] The method provided by the invention can make the polymerization reaction more complete through three polymerization reactions, so as to form a network-like hyperbranched polyacrylate adhesive with a phenolic polyamine structure, so that the adhesive has better adhesion and temperature resistance.

[0087] The present invention also provides a PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive described in the above technical solution or the hyperbranched polyacrylate adhesive prepared by the preparation method described in the above technical solution.

[0088] The present invention has no special limitation on the thickness of the polyimide film, which can be adjusted as needed. In an embodiment of the present invention, the thickness of the polyimide film can be specifically 25 μm.

[0089] The thickness of the adhesive is not particularly limited in the present invention and can be adjusted as required. In an embodiment of the present invention, the thickness of the adhesive after drying can be specifically 25±1 μm.

[0090] The present invention has no special limitation on the preparation method of the PI tape, and any conventional preparation method of the PI tape can be used. In an embodiment of the present invention, the preparation method of the PI tape can be specifically as follows: coating a hyperbranched polyacrylate adhesive on a polyimide film, drying it, and then laminating it with a silicone oil film to obtain the PI tape.

[0091] The present invention has no particular limitation on the coating method. A conventional coating method can be used to form an adhesive coating with uniform thickness on the polyimide film.

[0092] In the present invention, the drying temperature is preferably 130-150° C., more preferably 140° C.; the drying time is preferably 2-4 min, more preferably 3 min.

[0093] The invention utilizes branched phenolic polyamine acrylic acid modified monomer and acrylate polymerization to improve the heat resistance of acrylate, introduces a phenolic skeleton, solves the internal stress caused by thermal shrinkage at high temperature, and the special structure of the hyperbranched polymer enables it to maintain good dimensional stability and chemical stability at high temperature, so it is coated on a polyimide film to obtain a PI tape with excellent heat resistance and adhesion.

[0094] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0095] Example 1

[0096] A method for preparing a branched phenolic polyamine acrylic acid modified monomer comprises: mixing a branched polyamine as shown in formula (I), phenol and formaldehyde at a molar ratio of 1:6:6, adding acid to adjust the pH value to about 5, stirring evenly, performing a Mannich reaction at 35°C for 3 hours, and drying to obtain a branched phenolic polyamine; mixing the branched phenolic polyamine with acrylic acid at a molar ratio of 1:6, performing a condensation reaction at 85°C for 6 hours, and then drying to obtain a branched phenolic polyamine acrylic acid modified monomer;

[0097] A hyperbranched polyacrylate adhesive is obtained by polymerization reaction of the following raw materials, calculated by weight: soft monomer: 40 parts of butyl acrylate and 20 parts of isooctyl acrylate; hard monomer: 10 parts of acrylic acid and 10 parts of methyl acrylate; functional monomer: 1 part of 2-hydroxyethyl acrylate; 5 parts of branched phenolic polyamine acrylic acid modified monomer; initiator: 0.5 parts of azobisisobutyronitrile; crosslinking agent: 1 part of amino resin crosslinking agent (model: Hydroxyte 325); solvent: 50 parts of ethyl acetate;

[0098] The preparation method of the hyperbranched polyacrylate adhesive is:

[0099] (1) mixing a branched phenolic polyamine acrylic acid modified monomer, a soft monomer, a hard monomer and a functional monomer to obtain a monomer mixture;

[0100] (2) mixing an initiator and a solvent to obtain an initiator solution;

[0101] (3) stirring and heating one-half of the monomer mixture obtained in step (1) and one-third of the initiator solution obtained in step (2) in a reaction kettle to 86° C., and performing a first polymerization reaction at 86° C. for 0.5 h to obtain a first polymer solution;

[0102] (4) mixing the remaining part of the monomer mixture obtained in step (1) and one third of the initiator solution obtained in step (2) in a constant pressure dropping funnel, and then dripping the mixture into the first polymer solution obtained in step (3). The dripping is completed within 2 hours, and a second polymerization reaction is carried out at 86° C. for 6 hours to obtain a second polymer solution;

[0103] (5) adding one third of the initiator solution obtained in step (2) to the second polymer solution obtained in step (4), mixing, and performing a third polymerization reaction at 86° C. for 3 h, and cooling to 50° C. to obtain a glue solution;

[0104] (6) Evenly mixing the adhesive obtained in step (5) with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

[0105] Example 2

[0106] A hyperbranched polyacrylate adhesive is obtained by polymerization reaction of the following raw materials, calculated by weight: soft monomer: 40 parts of butyl acrylate and 20 parts of isooctyl acrylate; hard monomer: 10 parts of acrylic acid and 10 parts of methyl acrylate; functional monomer: 1 part of 2-hydroxyethyl acrylate; 8 parts of branched phenolic polyamine acrylic acid modified monomer prepared by the method of Example 1; initiator: 0.5 parts of azobisisobutyronitrile; crosslinking agent: 1 part of amino resin crosslinking agent (Hydrogen 325); solvent: 50 parts of ethyl acetate;

[0107] The preparation method of the hyperbranched polyacrylate adhesive is the same as that of Example 1.

[0108] Example 3

[0109] A hyperbranched polyacrylate adhesive is obtained by polymerization reaction of the following raw materials, calculated by weight: a soft monomer is 70 parts of butyl acrylate; a hard monomer is 5 parts of acrylic acid and 15 parts of methyl methacrylate; a functional monomer is 2 parts of glycidyl acrylate; 5 parts of branched phenolic polyamine acrylic acid modified monomer prepared by the method of Example 1; an initiator is 0.5 parts of azobisisobutyronitrile; a crosslinking agent is 1 part of an amino resin crosslinking agent (Hydrogen 325); a solvent is 60 parts of ethyl acetate;

[0110] The preparation method of the hyperbranched polyacrylate adhesive is:

[0111] (1) mixing a branched phenolic polyamine acrylic acid modified monomer, a soft monomer, a hard monomer and a functional monomer to obtain a monomer mixture;

[0112] (2) mixing an initiator and a solvent to obtain an initiator solution;

[0113] (3) stirring and heating one-half of the monomer mixture obtained in step (1) and one-third of the initiator solution obtained in step (2) in a reaction kettle to 88° C., and performing a first polymerization reaction at 88° C. for 1 hour to obtain a first polymer solution;

[0114] (4) mixing the remaining part of the monomer mixture obtained in step (1) and one third of the initiator solution obtained in step (2) in a constant pressure dropping funnel, and then dripping the mixture into the first polymer solution obtained in step (3). The dripping is completed within 1.5 hours, and a second polymerization reaction is carried out at 88° C. for 4 hours to obtain a second polymer solution;

[0115] (5) adding one third of the initiator solution obtained in step (2) to the second polymer solution obtained in step (4), mixing, and performing a third polymerization reaction at 88° C. for 4 h, and cooling to 50° C. to obtain a glue solution;

[0116] (6) Evenly mixing the adhesive obtained in step (5) with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

[0117] Example 4

[0118] A hyperbranched polyacrylate adhesive is obtained by polymerization reaction of the following raw materials, calculated by weight: soft monomer: 70 parts of isooctyl acrylate and 10 parts of butyl acrylate; hard monomer: 12 parts of acrylic acid and 15 parts of methyl methacrylate; functional monomer: 2 parts of 2-hydroxyethyl acrylate; 12 parts of branched phenolic polyamine acrylic acid modified monomer prepared by the method of Example 1; initiator: 0.5 parts of azobisisobutyronitrile; crosslinking agent: 1 part of amino resin crosslinking agent (Hydrogen 325); solvent: 50 parts of ethyl acetate and 20 parts of toluene;

[0119] The preparation method of the hyperbranched polyacrylate adhesive is the same as that of Example 1.

[0120] Example 5

[0121] A hyperbranched polyacrylate adhesive is obtained by polymerization reaction of the following raw materials, calculated by weight: soft monomer: 60 parts of isooctyl acrylate and 20 parts of butyl acrylate; hard monomer: 12 parts of acrylic acid; functional monomer: 2 parts of 2-hydroxyethyl acrylate; 15 parts of branched phenolic polyamine acrylic acid modified monomer prepared by the method of Example 1; initiator: 0.5 parts of azobisisobutyronitrile; crosslinking agent: 1 part of amino resin crosslinking agent (Hydrogen 325); solvent: 40 parts of ethyl acetate and 30 parts of toluene;

[0122] The preparation method of the hyperbranched polyacrylate adhesive is the same as that of Example 1.

[0123] Example 6

[0124] A hyperbranched polyacrylate adhesive is obtained by polymerization reaction of the following raw materials, calculated by weight: soft monomer: 60 parts of butyl acrylate and 10 parts of lauryl acrylate; hard monomer: 10 parts of methyl acrylate and 8 parts of acrylic acid; functional monomer: 3 parts of glycidyl methacrylate; 10 parts of branched phenolic polyamine acrylic acid modified monomer prepared by the method of Example 1; initiator: 0.5 parts of azobisisobutyronitrile; crosslinking agent: 1 part of amino resin crosslinking agent (Hydrogen 325); solvent: 30 parts of ethyl acetate and 30 parts of toluene;

[0125] The preparation method of the hyperbranched polyacrylate adhesive is:

[0126] (1) mixing a branched phenolic polyamine acrylic acid modified monomer, a soft monomer, a hard monomer and a functional monomer to obtain a monomer mixture;

[0127] (2) mixing an initiator and a solvent to obtain an initiator solution;

[0128] (3) stirring and heating one-half of the monomer mixture obtained in step (1) and one-third of the initiator solution obtained in step (2) in a reaction kettle to 88° C., and performing a first polymerization reaction at 88° C. for 1 hour to obtain a first polymer solution;

[0129] (4) mixing the remaining part of the monomer mixture obtained in step (1) and one third of the initiator solution obtained in step (2) in a constant pressure dropping funnel, and then dripping the mixture into the first polymer solution obtained in step (3). The dripping is completed within 1.5 hours, and a second polymerization reaction is carried out at 88° C. for 4 hours to obtain a second polymer solution;

[0130] (5) adding one third of the initiator solution obtained in step (2) to the second polymer solution obtained in step (4), mixing, and performing a third polymerization reaction at 88° C. for 4 h, and cooling to 50° C. to obtain a glue solution;

[0131] (6) Evenly mixing the adhesive obtained in step (5) with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

[0132] Example 7

[0133] A PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive prepared in Example 1;

[0134] The preparation method of the PI tape is as follows: the hyperbranched polyacrylate adhesive prepared in Example 1 is coated on a 25 μm polyimide film, dried at 140° C. for 3 min, the dry adhesive thickness is 25±1 μm, and then silicone oil film is laminated to obtain the PI tape.

[0135] Example 8

[0136] A PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive prepared in Example 2;

[0137] The preparation method of the PI tape is as follows: the hyperbranched polyacrylate adhesive prepared in Example 2 is coated on a 25 μm polyimide film, dried at 140° C. for 3 min, the dry adhesive thickness is 25±1 μm, and then silicone oil film is laminated to obtain the PI tape.

[0138] Example 9

[0139] A PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive prepared in Example 3;

[0140] The preparation method of the PI tape is as follows: the hyperbranched polyacrylate adhesive prepared in Example 3 is coated on a 25 μm polyimide film, dried at 140° C. for 3 min, the dry adhesive thickness is 25±1 μm, and then silicone oil film is laminated to obtain the PI tape.

[0141] Example 10

[0142] A PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive prepared in Example 4;

[0143] The preparation method of the PI tape is as follows: the hyperbranched polyacrylate adhesive prepared in Example 4 is coated on a 25 μm polyimide film, dried at 140° C. for 3 min, the dry adhesive thickness is 25±1 μm, and then silicone oil film is laminated to obtain the PI tape.

[0144] Embodiment 11

[0145] A PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive prepared in Example 5;

[0146] The preparation method of the PI tape is as follows: the hyperbranched polyacrylate adhesive prepared in Example 5 is coated on a 25 μm polyimide film, dried at 140° C. for 3 min, the dry adhesive thickness is 25±1 μm, and then silicone oil film is laminated to obtain the PI tape.

[0147] Example 12

[0148] A PI tape, comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive prepared in Example 6;

[0149] The preparation method of the PI tape is as follows: the hyperbranched polyacrylate adhesive prepared in Example 6 is coated on a 25 μm polyimide film, dried at 140° C. for 3 min, the dry adhesive thickness is 25±1 μm, and then silicone oil film is laminated to obtain the PI tape.

[0150] Test Case

[0151] The glue solutions obtained in Examples 1 to 6 were subjected to viscosity tests, and the results are shown in Table 1.

[0152] Table 1 Viscosity test results of the glue obtained in Examples 1 to 6

[0153] Sample Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Viscosity (GB / T20794-2013) 4700cps 5000cps 5100cps 4300cps 5100cps 5500cps

[0154] The PI tapes prepared in Examples 7 to 12 were post-cured at 50° C. for 72 h and subjected to temperature resistance test, peel strength test, electrolyte resistance test and dynamic shear test. The test results are shown in Table 2.

[0155] Table 2 Performance test results of PI tapes prepared in Examples 7 to 12

[0156]

[0157] It can be seen from the above test results that the PI tape prepared by the present invention has excellent heat resistance, adhesion and electrolyte resistance. This is because the branched phenolic polyamine acrylic acid modified monomer of the present invention introduces branched polyamines, and the hyperbranched polymer per unit mass has a very large surface area, which is conducive to enhancing the contact and interaction with the adherend, and improving the bonding strength and wettability of the adhesive; the present invention utilizes branched phenolic polyamine acrylic acid modified monomers and acrylate polymerization to improve the heat resistance of acrylate, introduces a phenolic skeleton, solves the internal stress caused by thermal shrinkage at high temperature, and improves the heat resistance of the adhesive. Therefore, the PI tape has excellent heat resistance and adhesion.

[0158] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A hyperbranched polyacrylate adhesive, obtained by polymerization of raw materials including the following components, in parts by mass: The preparation method of the branched phenolic polyamine acrylic acid modified monomer comprises: The branched polyamine, phenol and formaldehyde are mixed and subjected to a Mannich reaction to obtain a branched phenolic polyamine; The branched phenolic polyamine is mixed with acrylic acid to carry out a condensation reaction to obtain a branched phenolic polyamine acrylic acid modified monomer.

2. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that The soft monomer includes one or more of butyl acrylate, isooctyl acrylate and lauryl acrylate.

3. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that The hard monomer includes one or more of vinyl acetate, acrylic acid, acrylamide, styrene, methyl acrylate and methyl methacrylate.

4. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that: The functional monomers include one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, N-hydroxyacrylamide and ethyl methacrylate.

5. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that: The molar ratio of the branched polyamine, phenol and formaldehyde is 1:6:

6.

6. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that: The temperature of the Mannich reaction is 25-50° C., and the time of the Mannich reaction is 3-6 hours.

7. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that: The molar ratio of the branched phenolic polyamine to acrylic acid is 1:2-8.

8. The hyperbranched polyacrylate adhesive according to claim 1, characterized in that: The cross-linking agent includes one or more of isocyanates, amino resins, metal organic compounds and aziridines.

9. The method for preparing the hyperbranched polyacrylate adhesive according to any one of claims 1 to 8, characterized in that: The preparation method of the hyperbranched polyacrylate adhesive comprises: mixing branched phenolic polyamine acrylic acid modified monomer, soft monomer, hard monomer, functional monomer, initiator and solvent, and performing polymerization reaction to obtain adhesive solution; The glue solution is mixed with a cross-linking agent to obtain a hyperbranched polyacrylate adhesive.

10. A PI tape comprising a polyimide film and an adhesive coated on the polyimide film, wherein the adhesive is the hyperbranched polyacrylate adhesive according to any one of claims 1 to 8 or the hyperbranched polyacrylate adhesive prepared by the preparation method according to claim 9.

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