Electrically visbreaking adhesive composition, adhesive and product thereof

Abstract

The invention relates to the technical field of adhesives, in particular to an electric visbreaking adhesive composition, an adhesive and a product thereof. The electric visbreaking adhesive composition is prepared from the following components in parts by weight: 100 parts of an acrylic polymer, 2 to 15 parts of ionic liquid, 2 to 20 parts of an auxiliary agent and 0.1 to 5 parts of a cross-linking agent, wherein the total weight of monomer components in the acrylic polymer is 100 wt%, and the acrylic polymer contains 5-35 wt% of a nitrogen-containing monomer. In the electric visbreaking adhesive composition disclosed by the invention, a proper amount of nitrogen-containing monomer is introduced into the acrylic polymer, so that the compatibility of the acrylic polymer and the ionic liquid can be effectively improved, the ionic liquid is prevented from being separated out and participates in constructing an ionic migration channel, and the electric visbreaking effect is improved; the introduction of the auxiliary agent can promote the migration of the ionic liquid in a polymer network and improve the electric visbreaking response speed of the adhesive.

Description

Electro-adhesive compositions, adhesives and products thereof Technical Field

[0001] This invention relates to the field of adhesive technology, and in particular to an electro-tack reducing adhesive composition, adhesive, and articles thereof. Background Technology

[0002] Traditional pressure-sensitive adhesives have high peel strength to ensure bonding strength, making them difficult to peel off after application. Existing technologies include UV-based tack reduction and heat-based tack reduction. However, UV-based tack reduction is unsuitable for scenarios where the adhesive film is covered by the substrate, while heat-based tack reduction requires heating and is unsuitable for items that cannot withstand high temperatures, such as precision electronic components and batteries in mobile phones, laptops, and other electronic products.

[0003] To address this issue, electro-reducing adhesives have been developed and applied in recent years. These adhesives introduce ionic liquids into pressure-sensitive adhesives (PSAs) to enhance conductivity. When an external voltage is applied, the ions migrate, rapidly reducing the adhesive film's adhesion and enabling easy, non-destructive peeling. However, ionic liquids have poor compatibility with PSAs. Excessive ionic liquid addition can lead to precipitation, affecting the initial adhesion and bond stability of the PSAs. Conversely, insufficient addition results in low electro-reducing efficiency, making effective adhesion reduction difficult. Therefore, developing an electro-reducing adhesive that balances initial adhesion, bond strength, and electro-reducing efficiency is of great significance.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an electro-tack reducing adhesive composition, adhesive and articles thereof. The electro-tack reducing adhesive composition of this invention has good adhesion properties before electro-tack reduction, and can quickly reduce tack after electro-tack reduction, with peel force reduced by more than 98.5%, and no adhesive residue after peeling, which is suitable for the tack reduction requirements of specific electronic products.

[0006] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides an electro-tack reducing adhesive composition comprising the following components by weight: 100 parts of an acrylic polymer, 2-15 parts of an ionic liquid, 2-20 parts of an additive, and 0.1-5 parts of a crosslinking agent; wherein, based on a total weight of 100 wt% of monomer components in the acrylic polymer, it contains 5-35 wt% of nitrogen-containing monomers.

[0007] Furthermore, based on a total monomer component weight of 100 wt% in the acrylic polymer, it contains 0 to 5 wt% carboxyl monomers.

[0008] Furthermore, the mass ratio of the nitrogen-containing monomer to the ionic liquid is (1-7.5):1.

[0009] Furthermore, the mass ratio of the auxiliary agent to the ionic liquid is (1-3):1.

[0010] Furthermore, the cation of the ionic liquid includes at least one of imidazolium cation, quaternary ammonium cation, pyridinium cation, and phosphonium cation.

[0011] Furthermore, the additive includes polyethylene oxide.

[0012] Furthermore, the number-average molecular weight of the polyoxyethylene is 100–2,000 g / mol.

[0013] Furthermore, the electro-tack reducing adhesive composition also includes a tackifying resin.

[0014] Furthermore, the content of the tackifying resin is 0 to 25 parts relative to 100 parts by weight of the acrylic polymer.

[0015] A second aspect of the present invention provides an adhesive comprising the electro-tack reducing adhesive composition provided in the first aspect of the present invention.

[0016] A third aspect of the present invention provides an electro-tack reducing article, comprising an electro-tack reducing adhesive layer; said electro-tack reducing adhesive layer is made from the adhesive provided in the second aspect of the present invention, or contains an electro-tack reducing adhesive composition provided in the first aspect of the present invention.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In the electro-tack reducing adhesive composition of the present invention, the introduction of an appropriate amount of nitrogen-containing monomer into the acrylic polymer can improve the compatibility between the acrylic polymer and the ionic liquid, prevent the precipitation of the ionic liquid, and participate in the construction of ion migration channels, thereby improving the electro-tack reducing effect; the introduction of an appropriate amount of additives can promote the migration of ionic liquids and improve the electro-tack reducing response speed of the adhesive. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0019] It should be noted that "(meth)acrylate alkyl ester" in this invention refers to one or both of alkyl methacrylate and alkyl acrylate.

[0020] It should be noted that the weight parts of each component in this invention refer to the solid weight parts of the component, excluding the content of volatile components (such as solvents).

[0021] Electro-tack reducing adhesives work by applying an electric current to an adhesive containing an ionic liquid. Under the stimulation of the current, anions in the ionic liquid move towards the positive electrode, and cations move towards the negative electrode. The positive and negative electrodes are the external electrodes and the conductive layer of the electro-tack tape, respectively. When ions accumulate, the adhesive layer changes, leading to a decrease in adhesive strength. The amount of ionic liquid directly affects the electro-tack reducing effect; however, due to the poor compatibility between ionic liquids and adhesives, it is difficult to obtain an electro-tack reducing adhesive that achieves a balance between adhesiveness and electro-tack reduction properties.

[0022] Based on this, the first aspect of the present invention provides an electro-tack reducing adhesive composition comprising the following components by weight: 100 parts of acrylic polymer, 2-15 parts of ionic liquid, 2-20 parts of additives, and 0.1-5 parts of crosslinking agent; wherein, based on a total weight of 100 wt% of monomer components in the acrylic polymer, it contains 5-35 wt% of nitrogen-containing monomers.

[0023] In the electro-tack reducing adhesive composition of the present invention, an appropriate amount of nitrogen-containing monomer is introduced into the acrylic polymer. Since the nitrogen-containing monomer has high polarity, the nitrogen atom can act as a hydrogen bond acceptor. The cation of the ionic liquid also contains nitrogen, and the acidic hydrogen at the electron aggregation point of the ionic liquid cation can form a weak hydrogen bond with the nitrogen of the nitrogen-containing monomer. Since both contain nitrogen and have similar structures or polarities, the compatibility between the acrylic polymer and the ionic liquid can be effectively improved, the precipitation of the ionic liquid can be prevented, and the ionic liquid can participate in the construction of ion migration channels, resulting in an adhesive with balanced adhesion and electro-tack reducing properties. The introduction of a certain amount of additives can promote the migration of the ionic liquid and improve the electro-tack reducing response speed of the adhesive.

[0024] In a specific embodiment of the present invention, based on a total monomer weight of 100 wt% in the acrylic polymer, the acrylic polymer contains 5-35 wt% nitrogen-containing monomers, specifically 5 wt%, 8 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or any value between these two extremes. The inventors of this invention have discovered that adding an appropriate amount of nitrogen-containing monomers to the adhesive can improve the compatibility between the acrylic polymer and ionic liquids, prevent the precipitation of ionic liquids, and participate in the construction of ion migration channels, thereby improving the electro-tack reduction effect. If the amount of nitrogen-containing monomers added is too low, the dispersibility of the ionic liquids in the adhesive is poor, and they easily migrate to the interface, resulting in "debonding" at the bonding interface after long-term aging; if the amount of nitrogen-containing monomers added is too high, it will excessively "anchor" the ionic liquids, leading to a slow electro-tack reduction response.

[0025] In a specific embodiment of the present invention, the nitrogen-containing monomer includes at least one of 1-vinyl-2-pyrrolidone (NVP), 4-acryloylmorpholine (ACMO), acrylamide (AM), N,N-dimethylacrylamide (DMAA), N-vinylcaprolactam (NVCL), dimethylaminoethyl acrylate (DMAEA), dimethylaminoethyl methacrylate (DMAEMA), and N-vinylimidazole.

[0026] In a specific embodiment of the present invention, based on a total monomer component weight of 100 wt% in the acrylic polymer, the acrylic polymer contains 0-5 wt% carboxyl monomers, specifically 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0 wt%, or any value between these two extremes. To improve the adhesion of pressure-sensitive adhesives, traditional pressure-sensitive adhesives typically add a high content of carboxyl monomers. The inventors of this invention have discovered through in-depth research that the content of carboxyl monomers has a significant impact on the electro-tack reduction properties of adhesives. Specifically, when no carboxyl monomers are used, the electro-tack reduction response is most sensitive, and the peel force is significantly reduced after electro-tack reduction, but the initial adhesive force of the adhesive decreases, making it difficult to meet the requirements of high adhesive strength scenarios. As the content of carboxyl monomers increases, although it can effectively improve its adhesive force, its electro-tack reduction gradually decreases. When the content of carboxyl monomers exceeds 5 wt% of the total monomers, the electro-tack reduction performance drops sharply, failing to achieve an effective tack reduction effect. The introduction of an appropriate amount of carboxyl monomers can yield adhesives with balanced electro-tack reduction and bonding properties.

[0027] In a specific embodiment of the present invention, the carboxyl monomer includes at least one of acrylic acid (AA), methacrylic acid, and itaconic acid.

[0028] In a specific embodiment of the present invention, based on a total monomer component weight of 100 wt% in the acrylic polymer, the acrylic polymer contains 1 to 10 wt% hydroxyl monomers, specifically 1 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, or any value between the two extremes. Introducing an appropriate amount of hydroxyl monomers into the acrylic polymer can improve the cohesive strength of the adhesive.

[0029] In a specific embodiment of the present invention, the hydroxyl monomer is selected from hydroxyl-containing (meth)acrylate monomers. Further, the hydroxyl-containing (meth)acrylate monomers include at least one of 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl acrylate (HPA), 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate (4-HBA), and 4-hydroxybutyl methacrylate.

[0030] In a specific embodiment of the present invention, based on a total weight of 100 wt% of monomer components in the acrylic polymer, the acrylic polymer contains 60 to 92 wt% of alkyl (meth)acrylates with 1 to 14 alkyl carbon atoms, specifically 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 92 wt%, or any value between the two extremes.

[0031] In a specific embodiment of the present invention, the alkyl acrylate with 1 to 14 alkyl carbon atoms includes at least one of methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), isononyl acrylate and lauryl acrylate (LA).

[0032] The acrylic polymers of the present invention can be prepared by conventional polymerization methods, such as free radical polymers.

[0033] In one specific embodiment, the preparation of the acrylic polymer includes: mixing the monomer components, adding a certain amount of solvent and initiator, heating to initiate polymerization under a protective atmosphere, and obtaining the acrylic polymer after the reaction is completed.

[0034] In a specific embodiment of the present invention, the initiator may be a conventional initiator, such as an azo initiator or a peroxide initiator; azo initiators include, but are not limited to, azobisisobutyronitrile (AIBN), azobisisoheptanenitrile, and azobisisovalerate, etc., and peroxide initiators include, but are not limited to, benzoyl peroxide (BPO) and methyl ethyl ketone peroxide.

[0035] In a specific embodiment of the present invention, the amount of the initiator is 0.1 to 1.5 parts, based on a total weight of 100 parts by weight of monomer components in the acrylic polymer.

[0036] In a specific embodiment of the present invention, the polymerization reaction temperature is 60-80°C and the polymerization reaction time is 2-10 hours.

[0037] In specific embodiments of the present invention, the solvent includes, but is not limited to, ethyl acetate, propyl acetate, toluene, xylene, benzene, cyclohexane, methanol, ethanol, propanol, diethyl ether, acetone, etc. The amount of solvent used is not specifically limited and can be adjusted according to the solid content of the acrylic polymer, which can be 20-40%.

[0038] In a specific embodiment of the present invention, in the electro-tack reducing adhesive composition, the amount of the ionic liquid is 2 to 15 parts relative to 100 parts by weight of the acrylic polymer, specifically 2 parts, 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, or any value between the two extremes.

[0039] In a specific embodiment of the present invention, the cation of the ionic liquid includes at least one selected from imidazolium cations, quaternary ammonium salt cations, pyridinium cations, and phosphonium cations, preferably imidazolium cations. Further, the imidazolium cation may include 1-ethyl-3-methylimidazolium cation ([EMIM)). + ) or 1-butyl-3-methylimidazolium cation ([BMIM) + ).

[0040] In a specific embodiment of the present invention, the anion of the ionic liquid can be bis(trifluoromethanesulfonyl)imide anion ((CF3SO2)2N). - [TFSI] - ), bis(fluorosulfonyl)imide anion ((FSO2)2N - [FSI] - Tetrafluoroborate anion ([BF4]) - ), carboxylate anion ([COO) - Sulfate ions ([SO4]) 2- At least one of the following, preferably bis(trifluoromethanesulfonyl)imine anion ([TFSI]). - ).

[0041] In a specific embodiment of the present invention, the ionic liquid may be [EMIM][TFSI].

[0042] In a specific embodiment of the present invention, in the electro-tack reducing adhesive composition, the amount of the additive is 2 to 20 parts relative to 100 parts by weight of the acrylic polymer, specifically 2 parts, 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, or any value between the two extremes. The additive can promote the migration of ionic liquids in the polymer network, improving the response speed and efficiency of electro-tack reducing.

[0043] In a specific embodiment of the present invention, the additive includes polyethylene oxide. Because polyethylene oxide has strong hygroscopic properties, it can absorb moisture from the environment and, when electricity is applied, facilitates the movement of ions in the ionic liquid, thereby promoting electro-viscosity reduction efficiency.

[0044] In a specific embodiment of the present invention, the number-average molecular weight of the polyethylene oxide is 100–2,000 g / mol, specifically 100 g / mol, 200 g / mol, 400 g / mol, 500 g / mol, 600 g / mol, 1,000 g / mol, 2,000 g / mol, or any value between these two extremes. Limiting the molecular weight of the polyethylene oxide to this range, with a lower molecular weight, can weaken the interchain entanglement of the polymer, which is beneficial for constructing ion channels and improving the viscosity reduction efficiency.

[0045] In a specific embodiment of the present invention, the polyethylene oxide may be polyethylene glycol within the above-defined number-average molecular weight range.

[0046] In a specific embodiment of the present invention, the mass ratio of the nitrogen-containing monomer to the ionic liquid in the acrylic polymer is (1–7.5):1, specifically 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 7.5:1, or any value between these two extremes. Controlling the mass ratio of the nitrogen-containing monomer to the ionic liquid in the acrylic polymer within the above range helps to balance the compatibility of the ionic liquid in the adhesive system and the adhesive properties of the adhesive.

[0047] In a specific embodiment of the present invention, the mass ratio of the additive to the ionic liquid is (1-3):1, specifically 1:1, 1.5:1, 2:1, 2.5:1, 3:1, or any value between the two extremes. Adjusting the mass ratio of the additive to the ionic liquid within the above range helps to maintain good initial adhesion while ensuring efficient ion migration and electro-tack reduction efficiency.

[0048] In a specific embodiment of the present invention, the content of the crosslinking agent is 0.1 to 5 parts relative to 100 parts by weight of the acrylic polymer, specifically 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 5 parts or any value between the two extremes.

[0049] In a specific embodiment of the present invention, the crosslinking agent is selected from at least one of isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and aziridine-based crosslinking agents.

[0050] In a specific embodiment of the present invention, the electro-tack reducing adhesive composition further includes a tackifying resin. The introduction of the tackifying resin can improve the initial adhesive force and cohesive strength of the adhesive.

[0051] In a specific embodiment of the present invention, the content of the tackifying resin is 0 to 25 parts relative to 100 parts by weight of the acrylic polymer, specifically 0 parts, 0.1 parts, 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or any value between the two extremes.

[0052] In a specific embodiment of the present invention, the tackifying resin includes at least one of terpene resin, rosin and rosin-modified resin, and petroleum resin.

[0053] A second aspect of the present invention provides an adhesive comprising the electro-tack reducing adhesive composition provided in the first aspect of the present invention.

[0054] In this invention, there are no restrictions on the preparation method of the adhesive, and commonly used preparation methods can be used. This invention provides an optional method for preparing an adhesive, comprising the following steps: stirring and mixing an acrylic polymer, an ionic liquid, an additive, a crosslinking agent, and an optional tackifying resin until homogeneous, allowing the mixture to stand to defoam, thereby obtaining the adhesive to be coated.

[0055] In a specific embodiment of the present invention, a certain amount of solvent may be added during the preparation of the adhesive to promote the uniformity of mixing of the components and facilitate coating. Optionally, the solid content of the adhesive may be 15-30% to ensure that the adhesive has suitable leveling properties. In a specific embodiment of the present invention, the solvent may be a conventional organic solvent, such as those listed above.

[0056] It is understood that, for the convenience of production, transportation, and sales, the adhesive of the present invention only limits the composition of the components and not the form in which the components exist; that is, the components can be mixed together or stored separately. The mixed or separate storage method can be selected according to the actual use.

[0057] A third aspect of the present invention provides an electro-tack reducing article, comprising an electro-tack reducing adhesive layer; said electro-tack reducing adhesive layer is made from the adhesive provided in the second aspect of the present invention, or contains an electro-tack reducing adhesive composition provided in the first aspect of the present invention.

[0058] In specific embodiments of the present invention, the electro-adhesive product may include adhesive sheets, tapes, etc. The specific type can be adjusted according to actual needs.

[0059] In a specific embodiment of the present invention, the thickness of the electro-adhesive layer is 10–200 μm.

[0060] The present invention also provides a method for preparing the above-mentioned electro-tack reducing product, comprising the following steps: applying an adhesive to the surface of a support film and drying it to obtain an electro-tack reducing adhesive layer.

[0061] The support film can be a conductive substrate or a release film. The conductive substrate can be a PET substrate with a conductive metal layer (e.g., aluminum, copper, nickel, chromium, etc.) or a PET substrate with a conductive coating (e.g., conductive graphite). Preferably, it has a conductive metal layer on the PET substrate surface. The metal layer is attached to the PET substrate surface by conventional methods such as adhesive bonding or vapor deposition. The thickness of the PET substrate can be set to 1~25 μm, and the thickness of the metal layer can be set to 0.05~20 μm. The release film can be selected from conventional PET release films. The thickness of the release film can be freely selected according to actual needs and is not particularly limited. For example, it can be set to 25~100 μm, specifically 25 μm, 30 μm, 40 μm, 50 μm, 80 μm, 100 μm, or any value between these two extremes.

[0062] To facilitate winding, packaging, and transportation, another layer of release film can be applied to the other surface of the electro-adhesive layer.

[0063] The coating method is not limited and can be conventional coating methods such as roller coating, blade coating or dip coating.

[0064] In a specific embodiment of the present invention, the drying temperature is 90-110°C and the drying time is 2-5 min.

[0065] The following specific embodiments further illustrate the purpose and advantages of the present invention, but these embodiments should not be regarded as limitations of the present invention. In the following embodiments, 1 g represents 1 part by weight.

[0066] Example 1: Preparation of acrylic polymer: 82 g BA, 15 g ACMO, 1 g AA, 2 g HEA and 150 g ethyl acetate were added to a reaction vessel. 0.1 g AIBN dissolved in 4 g ethyl acetate was added to the reaction vessel. The mixture was stirred and nitrogen gas was introduced. The mixture was heated to 60°C and reacted for 4 h. Then 0.5 g AIBN dissolved in 10 g ethyl acetate was added, and the mixture was heated to 75°C and reacted for 3 h. Finally, an appropriate amount of ethyl acetate was added to obtain an acrylic polymer with a solid content of 30%.

[0067] 100 g of the acrylic polymer (solid weight), 10 g of rosin resin (K803L produced by Guangzhou Kemao Linhua Group Co., Ltd.), 5 g of ionic liquid [EMIM][TFSI] (Shanghai Aladdin Biochemical Technology Co., Ltd.), 5 g of polyethylene glycol PEG200 (Shanghai Aladdin Biochemical Technology Co., Ltd., number average molecular weight of 200 g / mol), 1 g of isocyanate crosslinking agent (Desmodur® N 75 produced by Covestro Ltd.), and a certain amount of ethyl acetate were mixed evenly and allowed to stand to defoam, resulting in an adhesive with a solid content of 20%. The adhesive was then coated onto the metal layer surface of a conductive substrate (6 μm conductive layer, 14 μm PET substrate) and dried in an oven at 100℃ for 3 min to form a 50 μm thick adhesive layer. A 50 μm thick PET release film was then coated onto the surface to obtain an electro-tack adhesive sheet.

[0068] Example 2 This example is based on Example 1, except that the amount of some components in the adhesive is different. The preparation method and solid content are the same as in Example 1. The specific differences are as follows: ionic liquid [EMIM][TFSI] 2 g, PEG200 2 g.

[0069] Example 3 This example is based on Example 1, except that the amount of some components in the adhesive is different. The preparation method and solid content are the same as in Example 1. The specific differences are as follows: 15 g of ionic liquid [EMIM][TFSI] and 15 g of PEG200.

[0070] Example 4 group: This example group is based on Example 1, except that the amount of BA and AA in the acrylic polymer in the adhesive is different. The preparation method and solid content are the same as in Example 1. The specific differences are as follows: Example 4a: 83 g BA, no AA; Example 4b: 78 g BA, 5 g AA; Example 4c: 76 g BA, 7 g AA.

[0071] Example 5 group was conducted in accordance with Example 1, with the only difference being the amount of BA and ACMO in the acrylic polymer in the adhesive. The preparation method and solid content were the same as in Example 1, and the specific differences are as follows: Example 5a: 92 g BA, 5 g ACMO, nitrogen monomer to ionic liquid mass ratio of 1:1; Example 5b: 62 g BA, 35 g ACMO, nitrogen monomer to ionic liquid mass ratio of 7:1; Example 5c: 94 g BA, 3 g ACMO, nitrogen monomer to ionic liquid mass ratio of 0.6:1; Example 5d: 57 g BA, 40 g ACMO, nitrogen monomer to ionic liquid mass ratio of 8:1.

[0072] Example 6 group was conducted in accordance with Example 1, with the only difference being the amount of additives in the adhesive, to verify the effect of the mass ratio of additives to ionic liquid on product performance. The preparation method and solid content were the same as in Example 1, with the specific differences as follows: Example 6a: PEG200 10 g, additive to ionic liquid mass ratio 2:1; Example 6b: PEG200 15 g, additive to ionic liquid mass ratio 3:1; Example 6c: PEG200 2.5 g, additive to ionic liquid mass ratio 0.5:1; Example 6d: PEG200 17.5 g, additive to ionic liquid mass ratio 3.5:1.

[0073] Example 7 group was conducted in accordance with Example 1, with the only difference being the type of additives in the adhesive. The preparation method and solid content were the same as in Example 1, as detailed below: Example 7a: PEG2000 (manufacturer: Shanghai Aladdin Biochemical Technology Co., Ltd., number average molecular weight 2,000 g / mol); Example 7b: PEG600 (manufacturer: Shanghai Aladdin Biochemical Technology Co., Ltd., number average molecular weight 600 g / mol); Example 7c: PEG100 (manufacturer: Shanghai Aladdin Biochemical Technology Co., Ltd., number average molecular weight 100 g / mol); Example 7d: PEG6000 (manufacturer: Shanghai Aladdin Biochemical Technology Co., Ltd., number average molecular weight 6,000 g / mol).

[0074] Comparative Example 1: This comparative example group was prepared in accordance with Example 1, except that the amount of additives in the adhesive was different. The preparation method and solid content were the same as those in Example 1. The specific differences are as follows: Comparative Example 1a: No PEG200 added; Comparative Example 1b: PEG200 1.5 g; Comparative Example 1c: PEG200 25 g.

[0075] The performance tests will be conducted on the adhesive sheets prepared in each embodiment and comparative example, testing their initial peel force and peel force after electro-adhesion reduction. The test results are shown in Table 1.

[0076] 180° Peel Force: The 180° peel force was tested according to the international standard ASTM D3330, "Standard Test Method for Peel Adhesion of Pressure-Sensitive Adhesive Tapes". A 25 mm × 300 mm tape was taken, and after peeling off the release film on one side, it was adhered to the surface of a clean SUS steel plate. It was rolled back and forth with a 1 kg stainless steel roller once and placed at room temperature (23±2℃, 50±5%RH) for 10 min to obtain the test sample. Then, the initial peel force was tested at a peel speed of 300 mm / min, expressed in N / cm. The test sample was connected to a 9V, 5A DC power supply, with the positive terminal connected to the metal layer surface of the conductive substrate and the negative terminal connected to the steel plate. After energizing for 60 s, the peel force after electro-adhesion reduction was tested in the same manner.

[0077] The viscosity reduction rate is calculated as follows: Viscosity reduction rate = (Initial peel force - Peel force after electro-viscosity reduction) / Initial peel force × 100% Table 1 Performance test results of different embodiments and comparative examples

[0078] The test results above show that the adhesive sheet prepared by the electro-tack reducing adhesive composition of the present invention has good adhesion before electro-tack reduction, and can quickly reduce adhesion after electro-tack reduction. The voltage and time for reducing adhesion are low, the electro-tack reduction response speed is fast, and the peeling force after reduction is low. The reduction rate can reach more than 98.5%, and there is no adhesive residue after peeling.

[0079] The test results from Example 4 show that an appropriate amount of carboxyl monomer can enhance the polarity and cohesive strength of acrylic polymers and improve the adhesion of adhesives. However, if the amount of carboxyl monomer is too high, it will significantly inhibit the electro-tack reduction effect of the adhesive.

[0080] The test results from Example 5 show that an appropriate amount of nitrogen-containing monomer can improve the compatibility between acrylic polymers and ionic liquids, prevent the precipitation of ionic liquids, and participate in the construction of ion migration channels, thereby improving the electro-tack reduction effect. If the content of nitrogen-containing monomers is too low, or the ratio of nitrogen-containing monomers to ionic liquids is too low, the dispersibility of ionic liquids in the adhesive is poor, and they easily migrate to the interface, causing interface weakening after long-term aging and resulting in "debonding". If the content of nitrogen-containing monomers is too high, it will excessively "anchor" the ionic liquids, resulting in a slow electro-tack reduction response.

[0081] The test results of Example 6 show that limiting the mass ratio of additives to ionic liquids helps to enhance the anti-tack effect of adhesives. When the mass ratio of additives to ionic liquids is too low, the electro-tack-reducing effect of additives on adhesives decreases, resulting in a decrease in electro-tack reduction rate. When the mass ratio of additives to ionic liquids is too high, excessive small molecule additives will reduce the adhesiveness of adhesives.

[0082] The test results of Example 7 show that additives within a limited number-average molecular weight range help to obtain adhesives with balanced adhesion and electro-tack reduction. When the number-average molecular weight of the additive is large, the additive has poor migration ability in the system, its crystallinity is enhanced, and it is difficult to fully dissolve in the system, resulting in precipitation. As the number-average molecular weight of the additive gradually decreases, the small molecules in the system will cause the adhesiveness of the adhesive to decrease. Therefore, the molecular weight of the additive should not be too low.

[0083] The test results of Comparative Example 1 show that when the adhesive contains no additives or its dosage is low, its electro-tack reduction rate is significantly lower. However, when its dosage is high, excessive small molecule additives in the system are prone to migrate to the interface, leading to debonding.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electro-tack reducing adhesive composition, characterized in that, It includes the following components by weight: 100 parts acrylic polymer, 2-15 parts ionic liquid, 2-20 parts additives, and 0.1-5 parts crosslinking agent; wherein, based on the total weight of the monomer components in the acrylic polymer being 100 wt%, it contains 5-35 wt% nitrogen-containing monomers.

2. The electro-tack reducing adhesive composition according to claim 1, characterized in that, Based on a total monomer weight of 100 wt% in the acrylic polymer, it contains 0 to 5 wt% carboxyl monomers.

3. The electro-tack reducing adhesive composition according to claim 1, characterized in that, The mass ratio of the nitrogen-containing monomer to the ionic liquid is (1-7.5):

1.

4. The electro-tack reducing adhesive composition according to claim 1 or 3, characterized in that, The mass ratio of the auxiliary agent to the ionic liquid is (1-3):

1.

5. The electro-tack reducing adhesive composition according to claim 4, characterized in that, The cations of the ionic liquid include at least one of imidazolium cations, quaternary ammonium cations, pyridinium cations, and phosphonium cations.

6. The electro-tack reducing adhesive composition according to claim 4, characterized in that, The additives include polyethylene oxide.

7. The electro-tack reducing adhesive composition according to claim 6, characterized in that, The number-average molecular weight of the polyoxyethylene is 100~2,000 g / mol.

8. The electro-tack reducing adhesive composition according to claim 1, characterized in that, The electro-tack reducing adhesive composition further includes a tackifying resin; the content of the tackifying resin is 0 to 25 parts relative to 100 parts by weight of the acrylic polymer.

9. An adhesive, characterized in that, Includes the electro-tack reducing adhesive composition according to any one of claims 1 to 8.

10. An electro-adhesive reducing product, characterized in that, Includes an electro-tack reducing adhesive layer; said electro-tack reducing adhesive layer is made from the adhesive of claim 9, or contains an electro-tack reducing adhesive composition of any one of claims 1 to 8.

Images