High-strength high-temperature-resistant mobile phone gum and preparation method thereof

Abstract

The invention provides a high-strength high-temperature-resistant mobile phone gum composition and a preparation method thereof, and a corresponding adhesive tape and a preparation method thereof. According to the high-strength high-temperature-resistant mobile phone gum composition, inorganic-organic hybridized abietic acid modified SiO2 microspheres are used as a tackifier, and hydrophenanthrene rings of rosinyl tricyclic diterpenes are introduced, so that the compatibility between the SiO2 microspheres and carbon-based resin and the mechanical property of gum are improved, and meanwhile, good bonding performance on bonded objects with different surface energies is realized. On the other hand, for the structural design of an isocyanate curing agent in the composition, the isocyanate curing agent with high steric hindrance and low reaction activity is used, and when the temperature rises, the isocyanate group with the high steric hindrance is gradually subjected to cross-linking reaction with hydroxyl in acrylate polyol or abietic acid modified SiO2 microspheres; due to the crosslinking density of the back adhesive, the cohesion of the adhesive layer is enhanced, and the phenomenon of adhesive residue caused by cohesion failure of the adhesive layer at high temperature is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly to a high-strength and high-temperature resistant mobile phone back adhesive composition, a preparation method thereof, and a corresponding tape and a preparation method thereof. Background Art

[0002] Mobile phone back adhesive is an adhesive used to fix the mobile phone back panel or other components to the mobile phone body. With the increasingly thin and light design and more powerful functions of smart phones, the selection and use of back adhesives become particularly important. Currently, the demand for back adhesives lies in having excellent bonding effects on materials with different surface energies. In particular, mobile phone components include high-surface-energy metals, high-polarity plastics such as ABS and PC, and low-surface-energy plastics such as PP, PE, and PS. An adhesive product with high peel strength for components with different surface energies is required.

[0003] In addition, the core component of a mobile phone is a lithium polymer battery with a high energy density. During the working process, it has to face a long charging-discharging cycle process. Moreover, the lithium polymer battery has a more compact structure design and is sensitive to temperature. Excessive temperature may affect the performance of the battery and even lead to the risk of fire or explosion. Traditional back adhesive materials are prone to cohesive failure under high-temperature environments or thermal shock conditions with short-term rapid temperature rise, manifested as degumming, delamination, or cracking of the adhesive layer. It is difficult to adapt to extreme high-temperature environments and cannot effectively conduct and dissipate heat. This not only reduces the performance of the battery but also may cause potential safety hazards.

[0004] Therefore, there is a very urgent demand for high-strength and high-temperature resistant mobile phone back adhesives in the current market. At the same time, it is also required that the mobile phone back adhesive can achieve good bonding performance for components with different surface energies as much as possible. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength and high-temperature resistant mobile phone back adhesive composition, a preparation method thereof, and a corresponding tape and a preparation method thereof.

[0006] To achieve the above technical purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, a high-strength and high-temperature resistant mobile phone back adhesive composition includes: polymer polyol, rosin acid-modified SiO2 microspheres, a curing agent, and a diluting solvent;

[0008] Among them, the polymer polyol is a polymer containing at least one hydroxyl group in the molecular chain, and is selected from acrylate polyol, polyurethane polyol, or polyester polyol;

[0009] Preferably, the polymer polyol is selected from acrylate polyol;

[0010] Preferably, in addition to hydroxyl groups, the active groups of the polymer polyol may further include any one or more combinations of isocyanate groups, epoxy groups, or carboxyl groups;

[0011] The rosin acid-modified SiO2 microspheres are obtained by reacting SiO2 microspheres activated by surface hydroxyl groups with rosin acid grafted with a silane coupling agent;

[0012] Preferably, the mass ratio of rosin acid grafted with a silane coupling agent to surface hydroxyl group-activated silica microspheres is (1:0.1)-(1:0.6), and more preferably, the mass ratio of rosin acid grafted with a silane coupling agent to surface hydroxyl group-activated silica microspheres is (1:0.2)-(1:0.5).

[0013] Preferably, the average diameter of the rosin acid-modified SiO2 microspheres does not exceed 5 μm;

[0014] Preferably, the SiO2 microspheres activated by surface hydroxyl groups are activated by adding hydrochloric acid to the SiO2 microspheres;

[0015] Preferably, the rosin acid grafted with a silane coupling agent is obtained by reacting rosin acid with a silane coupling agent containing an epoxy group;

[0016] Preferably, the molar ratio of rosin acid to the silane coupling agent containing an epoxy group is (0.7-0.1):1; more preferably, the molar ratio of rosin acid to the silane coupling agent containing an epoxy group is (0.8-0.9):1.

[0017] Wherein, the silane coupling agent containing an epoxy group is selected from any one or more combinations of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, or 3-glycidoxypropylmethyldiethoxysilane.

[0018] The curing agent is selected from curing agents capped with isocyanate groups, and each curing agent molecule includes at least 2 isocyanate groups, and its terminal structure is:

[0019] Preferably, the curing agent is selected from a curing agent capped with tetramethyl-m-xylylene diisocyanate (TMXDI) or a curing agent capped with 3-isopropyl-dimethylbenzyl isocyanate (TMI).

[0020] Further, the curing agent capped with tetramethyl-m-xylylene diisocyanate (TMXDI) is obtained by the condensation reaction of tetramethyl-m-xylylene diisocyanate with a polyol or a polyamine; preferably, the curing agent capped with tetramethyl-m-xylylene diisocyanate (TMXDI) is obtained by the condensation reaction of tetramethyl-m-xylylene diisocyanate with a polyol; more preferably, the polyol is polyethylene glycol with a molecular weight range of 100-600.

[0021] Further, the curing agent capped with 3-isopropyl-dimethylbenzyl isocyanate (TMI) is obtained by the hydrosilylation reaction of 3-isopropyl-dimethylbenzyl isocyanate (TMI) with a hydrosilane; preferably, the hydrosilane is selected from any one of tetramethyldihydrodisiloxane, methyltris(dimethylsilyloxy)silane or tetramethylcyclotetrasiloxane.

[0022] Further, the back glue composition comprises, by mass: 80-120 parts of acrylate resin, 30-70 parts of diluting solvent, 1-10 parts of rosin acid-modified SiO2 microspheres, and 0.5-5 parts of curing agent.

[0023] Preferably, the back glue composition comprises, by mass: 90-110 parts of acrylate resin, 40-60 parts of diluting solvent, 3-8 parts of rosin acid-modified SiO2 microspheres, and 0.5-3 parts of curing agent.

[0024] The diluting solvent is selected from any one or a combination of two of ester solvents or ether solvents; preferably, the ester solvent is selected from any one or a combination of ethyl acetate, butyl acetate or propylene glycol methyl ether acetate, and the ether solvent is selected from any one or a combination of propylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol butyl ether or dipropylene glycol methyl ether.

[0025] In a second aspect, a preparation method of a high-strength and high-temperature resistant mobile phone back glue comprises: uniformly mixing the above-mentioned back glue composition.

[0026] In a third aspect, a high-strength and high-temperature resistant mobile phone back glue cured glue layer is obtained by curing the above-mentioned back glue composition at a temperature of 60-180°C.

[0027] In a fourth aspect, a tape comprises: a substrate and a cured glue layer, and the cured glue layer is coated on at least one side or both sides of the substrate;

[0028] wherein, the substrate is selected from any one of polyethylene, polypropylene, polyimide or polyester, and the cured glue layer is the cured product of the above-mentioned high-strength and high-temperature resistant mobile phone back glue.

[0029] Preferably, the polyester is selected from any one of polyethylene terephthalate and polybutylene terephthalate.

[0030] Preferably, the base material is selected from uniaxially stretched films or biaxially stretched films, including: uniaxially stretched polyethylene, biaxially stretched polyethylene, uniaxially stretched polypropylene, biaxially stretched polypropylene, uniaxially stretched polyimide, biaxially stretched polyimide, uniaxially stretched polyester or biaxially stretched polyester.

[0031] Preferably, the thickness of the base material does not exceed 150 μm.

[0032] Preferably, the thickness of the cured adhesive layer does not exceed 50 μm.

[0033] In a fifth aspect, a method for preparing a tape includes: uniformly mixing the above-mentioned back adhesive composition and coating it on at least one side of a thin film base material, curing at a temperature of 60-180 °C, and laminating a release film on the surface of the cured product after curing.

[0034] Preferably, the above-mentioned back adhesive composition is uniformly mixed and coated on both sides of the thin film base material, cured at a temperature of 60-180 °C, and obtained after laminating the release film.

[0035] The beneficial effects of the present invention are as follows: Using inorganic-organic hybrid rosin acid-modified SiO2 microspheres as tackifiers, by introducing the hydrogenated phenanthrene ring of rosin-based tricyclic diterpenes, the hydrogenated phenanthrene ring structure improves the intermolecular interaction between SiO2 microspheres and the polymer main chain, improves the compatibility between SiO2 microspheres and carbon-based resins, and correspondingly improves the mechanical properties of the back adhesive. At the same time, the inorganic-organic hybrid rosin acid-modified SiO2 microspheres can be used in combination with conventional polymer resins to achieve good adhesion performance to adherends with different surface energies. In addition, the hydrogenated phenanthrene ring structure has a higher steric hindrance effect. Although SiO2 microspheres still retain a small amount of hydroxyl groups, their reactivity is very low under the shielding effect of the large steric hindrance of the hydrogenated phenanthrene ring and only crosslinks with isocyanate curing agents at high temperatures.

[0036] On the other hand, for the structural design of the isocyanate curing agent, using an isocyanate curing agent capped with TMXDI or TMI, due to its unique chemical structure, it can provide higher heat resistance, thereby maintaining adhesiveness for a longer time at high temperatures. At the same time, the isocyanate group capped with TMXDI or TMI has a higher steric hindrance and lower reactivity, and it is difficult to react with hydroxyl groups at room temperature. When the temperature rises, the high-steric hindrance isocyanate group gradually crosslinks with the hydroxyl groups in acrylate polyol or rosin acid-modified SiO2 microspheres, thereby increasing the crosslinking density of the back adhesive and enhancing the cohesion of the adhesive layer, avoiding cohesive failure of the adhesive layer at high temperatures and resulting in residual glue phenomenon. Description of the Drawings

[0037] Figure 1 SEM images of rosin acid-modified SiO2 microspheres for Examples 2-3.

[0038] Figure 2 XRD patterns of the surface hydroxyl-activated SiO2 microspheres of Example 1 and the rosin acid-modified SiO2 microspheres of Examples 2-3.

[0039] Figure 3 TG curves of the surface hydroxyl-activated SiO2 microspheres of Example 1 and the rosin acid-modified SiO2 microspheres from Example 2-1 to Example 2-6. Detailed implementation manners

[0040] Combined with the embodiments of the present invention below, the technical solutions in the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention. It should be noted that the terms used here are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0041] If the specific experimental conditions are not specified in the embodiments, they are usually in accordance with the conventional conditions in the art or the conditions recommended by the reagent company; the materials, reagents, etc. used in the embodiments, unless otherwise specified, can be obtained through commercial channels.

[0042] Example 1

[0043] Preparation of SiO2 microspheres: In ethanol, using 25 wt% aqueous ammonia solution as the basic catalyst, 0.03 g of KCl, 380 mL of ethanol, and 90 mL of 25 wt% aqueous ammonia solution were added to a flask. 60.4 g of TEOS and 520 mL of ethanol were continuously added dropwise to the flask using a peristaltic pump. The dropping time was 2 hours. During the dropping process, the temperature in the flask was controlled at 40 °C using a water bath. After the dropping was completed, the reaction was carried out at 40 °C for 16 hours. Subsequently, the bottom precipitate was separated by centrifugation, and the precipitate was washed twice with ethanol for purification. Finally, the precipitate was vacuum dried at room temperature to obtain 15.4 g of SiO2 microspheres.

[0044] Surface Hydroxyl Activation of SiO2 Microspheres: 15.4 g of SiO2 microspheres were added to 150 mL of 10% (v / v) hydrochloric acid and reacted at 80 °C for 12 hours under nitrogen protection. After the reaction, suction filtration was carried out, and the filter cake was washed with deionized water several times until the filtrate was neutral. The filter cake was collected and vacuum dried at 80 °C for 12 hours to obtain 14.6 g of light yellow activated SiO2 microspheres.

[0045] Example 2-1

[0046] Synthesis of 3-Glycidoxypropyltrimethoxysilane (KH560) Grafted Rosin Acid: KH560 grafted rosin acid was synthesized at a molar ratio of n(rosin acid):n(KH560) = 0.85:1. 128.5 g of mixed rosin acid with an effective content of 98 wt% (CAS: 514-10-3, Shanghai Tongtian Biotechnology) and 118 g of 3-glycidoxypropyltrimethoxysilane with an effective content of 98.5% (abbreviation: KH560, Jiangxi Hongbai New Materials) were added to a flask. 100 mL of xylene was used as a solvent to dissolve rosin acid, and then 2.5 g of catalyst octadecyltrimethylammonium chloride was added as a catalyst. The temperature was raised to 125 °C and refluxed for 12 hours, and then cooled to 80 °C for vacuum distillation to remove the solvent to obtain the product.

[0047] Preparation of Rosin Acid Modified SiO2 Microspheres: The mass ratio of KH560 grafted rosin acid to surface hydroxyl activated silica microspheres was designed to be 1:0.2. 4.0 g of surface hydroxyl activated silica microspheres were placed in a three-necked flask, and 38 mL of anhydrous toluene, 2 mL of anhydrous pyridine, and 20 g of KH560 grafted rosin acid were added in sequence. Ultrasonic dispersion was carried out for 30 min, and under nitrogen protection, the temperature was raised to 90 °C and refluxed for 24 hours. The solid in the reaction flask was suction filtered, and the filter cake was washed twice with ethyl acetate and methanol in sequence. Then it was vacuum dried at 80 °C for 12 hours to obtain 17.9 g of light yellow powdery product, which was rosin acid modified SiO2 microspheres.

[0048] Example 2-2

[0049] Synthesis of KH560 Grafted Rosin Acid: The same as Example 2-1.

[0050] Preparation of rosin acid-modified SiO2 microspheres: The mass ratio of KH560-grafted rosin acid to surface hydroxyl-activated silica microspheres was designed to be 1:0.25. 5.0 g of surface hydroxyl-activated silica microspheres were placed in a three-necked flask, and 48 mL of anhydrous toluene, 2 mL of anhydrous pyridine, and 20 g of KH560-grafted rosin acid were added successively. Ultrasonic dispersion was carried out for 30 min. Under the condition of nitrogen protection, the temperature was raised to 90 °C and refluxed for 24 hours. The solid in the reaction flask was filtered by suction, and the filter cake was washed twice with ethyl acetate and methanol in turn. Then, it was dried in vacuo at 80 °C for 12 hours to obtain 18.7 g of a pale yellow powdery product, which was rosin acid-modified SiO2 microspheres.

[0051] Example 2-3

[0052] Synthesis of KH560-grafted rosin acid: The same as Example 2-1.

[0053] Preparation of rosin acid-modified SiO2 microspheres: The mass ratio of KH560-grafted rosin acid to surface hydroxyl-activated silica microspheres was designed to be 1:0.32. 6.4 g of surface hydroxyl-activated silica microspheres were placed in a three-necked flask, and 60 mL of anhydrous toluene, 4 mL of anhydrous pyridine, and 20 g of KH560-grafted rosin acid were added successively. Ultrasonic dispersion was carried out for 30 min. Under the condition of nitrogen protection, the temperature was raised to 90 °C and refluxed for 24 hours. The solid in the reaction flask was filtered by suction, and the filter cake was washed twice with ethyl acetate and methanol in turn. Then, it was dried in vacuo at 80 °C for 12 hours to obtain 19.8 g of a pale yellow powdery product, which was rosin acid-modified SiO2 microspheres.

[0054] Example 2-4

[0055] Synthesis of KH560-grafted rosin acid: The same as Example 2-1.

[0056] Preparation of rosin acid-modified SiO2 microspheres: The mass ratio of KH560-grafted rosin acid to surface hydroxyl-activated silica microspheres was designed to be 1:0.4. 8.0 g of surface hydroxyl-activated silica microspheres were placed in a three-necked flask, and 75 mL of anhydrous toluene, 5 mL of anhydrous pyridine, and 20 g of KH560-grafted rosin acid were added successively. Ultrasonic dispersion was carried out for 30 min. Under the condition of nitrogen protection, the temperature was raised to 90 °C and refluxed for 24 hours. The solid in the reaction flask was filtered by suction, and the filter cake was washed twice with ethyl acetate and methanol in turn. Then, it was dried in vacuo at 80 °C for 12 hours to obtain 21.3 g of a pale yellow powdery product, which was rosin acid-modified SiO2 microspheres.

[0057] Example 2-5

[0058] Synthesis of KH560-grafted rosin acid: The same as Example 2-1.

[0059] Preparation of rosin acid modified SiO2 microspheres: The mass ratio of KH560 grafted rosin acid to surface hydroxyl-activated silica microspheres was designed to be 1:0.45. 9.0 g of surface hydroxyl-activated silica microspheres were placed in a three-necked flask, and 84 mL of anhydrous toluene, 6 mL of anhydrous pyridine, and 20 g of KH560 grafted rosin acid were added in sequence. Ultrasonic dispersion was carried out for 30 min. Under the protection of nitrogen, the temperature was raised to 90 °C and refluxed for 24 hours. The solid in the reaction flask was filtered by suction, and the filter cake was washed twice with ethyl acetate and methanol in sequence. Then it was dried in vacuo at 80 °C for 12 hours to obtain 23.5 g of a pale yellow powdery product, which was rosin acid modified SiO2 microspheres.

[0060] Examples 2-6

[0061] Synthesis of KH560 grafted rosin acid: The same as in Example 2-1.

[0062] Preparation of rosin acid modified SiO2 microspheres: The mass ratio of KH560 grafted rosin acid to surface hydroxyl-activated silica microspheres was designed to be 1:0.5. 10.0 g of surface hydroxyl-activated SiO2 microspheres were placed in a three-necked flask, and 92 mL of anhydrous toluene, 8 mL of anhydrous pyridine, and 20 g of KH560 grafted rosin acid were added in sequence. Ultrasonic dispersion was carried out for 30 min. Under the protection of nitrogen, the temperature was raised to 90 °C and refluxed for 24 hours. The solid in the reaction flask was filtered by suction, and the filter cake was washed twice with ethyl acetate and methanol in sequence. Then it was dried in vacuo at 80 °C for 12 hours to obtain 25.2 g of a pale yellow powdery product, which was rosin acid modified SiO2 microspheres.

[0063] Characterization of rosin acid modified SiO2 microspheres: The appearance of the rosin acid modified SiO2 microspheres prepared in Example 2-3 was observed by scanning electron microscopy (SEM); the SiO2 microspheres with surface hydroxyl activation in Example 1 and the rosin acid modified SiO2 microspheres prepared in Example 2-3 were respectively tested by XRD and compared; the thermogravimetric curves of the SiO2 microspheres with surface hydroxyl activation in Example 1 and the rosin acid modified SiO2 microspheres with different ratios from Example 2-1 to Example 2-6 were tested by TGA. The test temperature range was from room temperature to 700 °C, the heating rate was 20 °C / min, and the atmosphere was nitrogen atmosphere.

[0064] Example 3-1

[0065] Preparation of TMXDI-terminated curing agent: 88 g (0.44 mol) of polyethylene glycol PEG-200 was first dehydrated under reduced pressure at 100 °C for 1 hour, and then 122 g (0.5 mol) of tetramethyl-m-xylylene diisocyanate (TMXDI) was added to a three-necked flask. Stirring was started and nitrogen was continuously introduced. Under stirring, 0.6 g of the catalyst dibutyltin dilaurate (DBTDL) was added. After heating to 90 °C and reacting for 2 hours, the temperature was lowered to 50 °C, and unreacted monomers and solvents were removed by vacuum distillation. Subsequently, the TMXDI-terminated curing agent was obtained.

[0066] The TMXDI-terminated curing agent prepared in Example 3-1 is:

[0067]

[0068] The corresponding reaction formula:

[0069]

[0070] Example 3-2

[0071] Preparation of TMXDI-terminated curing agent: 240 g (0.4 mol) of polyethylene glycol PEG-600 was first dehydrated under reduced pressure at 100 °C for 1 hour, and then 122 g (0.5 mol) of tetramethyl-m-xylylene diisocyanate (TMXDI) was added to a three-necked flask. Stirring was started and nitrogen was continuously introduced. Under stirring, 1.2 g of the catalyst dibutyltin dilaurate (DBTDL) was added. After heating to 90 °C and reacting for 2 hours, the temperature was lowered to 50 °C, and unreacted monomers and solvents were removed by vacuum distillation. Subsequently, the TMXDI-terminated curing agent was obtained.

[0072] The TMXDI-terminated curing agent prepared in Example 3-2 is:

[0073]

[0074] The corresponding reaction formula:

[0075]

[0076] Example 3-3

[0077] Preparation of TMI-terminated curing agent: 40.3 g (0.15 mol) of raw material methyltris(dimethylsilyl)silane was dissolved in 60 mL of toluene and placed in a three-necked flask. 0.5 g of chloroplatinic acid-divinyltetramethyldisiloxane complex, 96.51 g of 3-isopropyl-α,α-dimethylbenzyl isocyanate (TMI, 0.48 mol) and 80 mL of toluene solvent were added dropwise to the flask. The reaction temperature was controlled at 90 °C and the addition was completed within 3 hours. Then, the reaction was continued at this temperature for 1 hour. After the reaction was completed, the unreacted monomers and solvents were removed by vacuum distillation, and then the TMI-terminated curing agent was obtained.

[0078] The TMI-terminated curing agent prepared in Example 3-3 is as follows:

[0079] The corresponding reaction formula:

[0080]

[0081] Structural characterization of the TMI-terminated curing agent prepared in Example 3-3: 1 H NMR (400 MHz): δ 0.01 - 0.11 (18H, 0.06(s), 0.06(s)), 0.49(3H, s), 0.80 - 0.92(6H, 0.86(d, J = 10.07 Hz), 0.86(d, J = 10.07 Hz), 0.86(d, J = 10.07 Hz), 0.86(d, J = 10.07 Hz)), 1.07 - 1.18(9H, 1.13(d, J = 6.97 Hz), 1.13(d, J = 6.97 Hz)), 1.46 - 1.56(18H, 1.51(s), 1.51(s), 1.51(s), 1.51(s)), 2.96 - 3.16(3H, 3.06(ddq, J = 10.07, 10.07, 6.97 Hz), 3.06(ddq, J = 10.07, 10.07, 6.97 Hz)), 6.30 - 6.41(3H, 6.36(ddd, J = 1.53, 1.04, 0.53 Hz), 6.36(ddd, J = 1.53, 1.04, 0.53 Hz)), 6.90 - 7.02(3H, 6.96(ddd, J = 7.91, 2.13, 1.04 Hz), 6.96(ddd, J = 7.91, 2.13, 1.04 Hz)), 7.08 - 7.29(6H, 7.14(ddd, J = 8.01, 2.13, 1.53 Hz), 7.14(ddd, J = 8.01, 2.13, 1.53 Hz), 7.22(ddd, J = 8.01, 7.91, 0.53 Hz), 7.22(ddd, J = 8.01, 7.91, 0.53 Hz)).

[0082] Example 4

[0083] Ratio of the back glue composition: 100 parts of acrylate polymer polyol DURO-TAK 2287 (Henkel of Germany, solid content 50.5%, functional group is hydroxyl group), 53 parts of diluting solvent ethyl acetate, 5.5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-1, and 1.5 parts of TMXDI-terminated curing agent prepared in Example 3-1.

[0084] Example 5

[0085] Configuration and coating of the back glue composition: Use 5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-1 and 1 part of TMI-terminated curing agent prepared in Example 3-3, and the rest is the same as Example 4.

[0086] Example 6

[0087] Configuration and coating of the back glue composition: Use 5.5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-2 and 1.5 parts of TMXDI-terminated curing agent prepared in Example 3-2, and the rest is the same as Example 4.

[0088] Example 7

[0089] Configuration and coating of the back glue composition: Use 5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-2 and 1 part of TMI-terminated curing agent prepared in Example 3-3, and the rest is the same as Example 4.

[0090] Example 8

[0091] Configuration and coating of the back glue composition: Use 5.5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-3, and the rest is the same as Example 4.

[0092] Example 9

[0093] Configuration and coating of the back glue composition: Use 5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-3 and 1 part of TMI-terminated curing agent prepared in Example 3-3, and the rest is the same as Example 4.

[0094] Example 10

[0095] Configuration and coating of the back glue composition: Use 5.5 parts of rosin acid modified SiO2 microspheres prepared in Example 2-4 and 1.5 parts of TMXDI-terminated curing agent prepared in Example 3-2, and the rest is the same as Example 4.

[0096] Example 11

[0097] Preparation and Coating of the Pressure-Sensitive Adhesive Composition: Use 5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-4 and 1 part of the TMI-capped curing agent prepared in Example 3-3, and the rest is the same as in Example 4.

[0098] Example 12

[0099] Preparation and Coating of the Pressure-Sensitive Adhesive Composition: Use 5.5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-5, and the rest is the same as in Example 4.

[0100] Example 13

[0101] Preparation and Coating of the Pressure-Sensitive Adhesive Composition: Use 5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-5 and 1 part of the TMI-capped curing agent prepared in Example 3-3, and the rest is the same as in Example 4.

[0102] Example 14

[0103] Preparation and Coating of the Pressure-Sensitive Adhesive Composition: Use 5.5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-6 and 1.5 parts of the TMXDI-capped curing agent prepared in Example 3-2, and the rest is the same as in Example 4.

[0104] Example 15

[0105] Preparation and Coating of the Pressure-Sensitive Adhesive Composition: Use 5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-6 and 1 part of the TMI-capped curing agent prepared in Example 3-3, and the rest is the same as in Example 4.

[0106] Comparative Example 1

[0107] Formulation of the Pressure-Sensitive Adhesive Composition: 100 parts of acrylate polymer polyol DURO-TAK 2287 (Henkel, Germany, solid content 50.5%, functional group is hydroxyl), 53 parts of diluting solvent ethyl acetate, 5.5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-3, and 1 part of Covestro Desmodur N3400 (HDI uretdione).

[0108] Comparative Example 2

[0109] Formulation of the Pressure-Sensitive Adhesive Composition: 100 parts of acrylate polymer polyol DURO-TAK 2287 (Henkel, Germany, solid content 50.5%, functional group is hydroxyl), 53 parts of diluting solvent ethyl acetate, 5 parts of the rosin acid-modified SiO2 microspheres prepared in Example 2-3, and 1.5 parts of Wanhua WANNATE MDI-100LL (carbodiimide-uretonimine modified MDI).

[0110] Comparative Example 3

[0111] Ratio of the pressure-sensitive adhesive composition: 100 parts of acrylate polymer polyol DURO-TAK 2287 (Henkel of Germany, solid content 50.5%, functional group is hydroxyl group), 53 parts of dilution solvent ethyl acetate, 5.5 parts of KH560 grafted rosin acid, and 1.5 parts of the curing agent capped with TMXDI prepared in Example 3-1.

[0112] Comparative Example 4

[0113] Ratio of the pressure-sensitive adhesive composition: 100 parts of acrylate polymer polyol DURO-TAK 2287 (Henkel of Germany, solid content 50.5%, functional group is hydroxyl group), 53 parts of dilution solvent ethyl acetate, 5.5 parts of unmodified surface-activated SiO2 microspheres, and 1.5 parts of the curing agent capped with TMXDI prepared in Example 3-1.

[0114] Comparative Example 5

[0115] Ratio of the pressure-sensitive adhesive composition: 100 parts of acrylate polymer polyol DURO-TAK 2287 (Henkel of Germany, solid content 50.5%, functional group is hydroxyl group), 53 parts of dilution solvent ethyl acetate, and 1.5 parts of the curing agent capped with TMXDI prepared in Example 3-1.

[0116] Coating process: Add the above components to the mixing tank according to the ratio, mix for 30 min, and then start coating with a coater. Coat the mixed adhesive solution on both sides of the PET substrate, control the coating thickness to be 25 ± 2 μm, bake at 105°C for 2 min to remove the solvent and form a glue layer, then use a unidirectionally stretched polypropylene film (MOPP) coated with a release agent as the release film to adhere to the pressure-sensitive adhesive layer, and then wind up and slit to obtain a double-sided pressure-sensitive adhesive tape.

[0117] Refer to the general method for testing pressure-sensitive adhesives currently to test the initial tack, 180° peel strength, and high-temperature performance indicators of the finished pressure-sensitive adhesive tapes obtained from the above examples and comparative examples. The initial tack refers to the American PSTC-6 standard, and the rolling ball flat stop test method is used for testing. Measure the distance that a steel ball with a diameter of 11.1 mm rolls over the adhesive surface. The smaller the distance, the higher the initial tack performance of the corresponding tape sample.

[0118] The 180° peel strength is tested according to the GB / T 2792-2014 standard at a temperature of (23 ± 2)°C and a relative humidity of (50 ± 5)%, and the peel strength of the pressure-sensitive adhesive tape on the surfaces of stainless steel plate, aluminum plate, PC plate, and PP plate is tested respectively.

[0119] The specific steps for the high-temperature performance test are to stick the pressure-sensitive adhesive on a stainless steel plate, place it in an oven set at 130 ± 2°C and bake for 2 h, take it out and immediately peel off the tape while it is hot, and observe whether there is residual adhesive on the surface of the stainless steel plate. If there is residual adhesive, it indicates cohesive failure of the glue layer.

[0120] The comparison of all the above test data is shown in Table 1 below.

[0121] Table 1

[0122]

[0123] First, for the characterization of rosin acid-modified SiO2 microspheres, from the SEM observation results ( Figure 1 ), the appearance of rosin acid-modified SiO2 microspheres is spherical, and the average diameter of the microspheres does not exceed 5 μm. From the XRD test results ( Figure 2 ), the crystal structures of the hydroxyl-activated SiO2 microspheres in Example 1 and the rosin acid-modified SiO2 microspheres in Examples 2-3 are the same, both based on the same SiO2. From Figure 3 the thermogravimetric test results, the weight loss of the hydroxyl-activated SiO2 microspheres in Example 1 is very low, and only a small amount of weight loss is caused by the condensation and dehydration of hydroxyl groups, and the remaining inorganic component SiO2 has no weight loss at 700 °C. From Example 2-1 to Example 2-6, the proportion of the inorganic component SiO2 microspheres gradually increases and the proportion of the organic component KH560-grafted rosin acid gradually decreases, and the corresponding weight loss rate also decreases, which conforms to the law that the higher the proportion of the organic component in the inorganic-organic hybrid, the greater the thermal weight loss.

[0124] From the analysis of the test data in Table 1, it can be seen that the tack of the back glue compositions in Examples 4-15 and the adhesion to different surface energy substrates are more balanced, and at the same time, it can meet the requirement of no cohesive failure during peeling at a high temperature of 130 °C * 2 h. It can be considered that the tack, cohesive force and adhesion of the three are balanced. Among them, due to the steric hindrance of the isocyanate group in the monomer, the TMXDI or TMI blocked curing agent is difficult to react with H2O or hydroxyl groups in the back glue at room temperature. Therefore, the back glue can maintain a lower crosslinking density at room temperature, avoiding affecting its tack and peel strength at room temperature. When the temperature rises, the high steric hindrance isocyanate group gradually crosslinks with the hydroxyl groups in the acrylate and rosin acid-modified SiO2 microspheres, thereby increasing the crosslinking density of the back glue and enhancing the cohesive force, avoiding cohesive failure of the glue layer and the appearance of residual glue at high temperature.

[0125] In Comparative Examples 1 and 2, aliphatic isocyanate and aromatic isocyanate are used to replace the TMXDI or TMI blocked curing agent respectively. Since the conventional isocyanate group has high reactivity and is easy to crosslink with the hydroxyl groups in the acrylate polyol or rosin acid-modified SiO2 microspheres, thereby increasing the crosslinking density of the back glue layer, no cohesive failure occurs during peeling at high temperature. However, the isocyanate and hydroxyl groups crosslink in advance at room temperature, resulting in a decrease in the peel strength of the back glue tested on stainless steel plates, aluminum plates, PC plates and PP plates at room temperature, and the adhesion performance is not as good as that of Examples 4-15.

[0126] In Comparative Example 3, SiO2 microspheres were not used, but KH560-grafted rosin acid was added to replace the rosin acid-modified SiO2 microspheres. After the addition of KH560-grafted rosin acid, the initial tack of the back glue could be significantly improved. However, since insufficient crosslinking sites could not be provided, the adhesive layer was prone to cohesive failure during the high-temperature peeling process, resulting in residual glue. At the same time, the adhesion to the low-surface-energy PP board decreased.

[0127] In Comparative Example 4, unmodified SiO2 microspheres were used, and the hydrogenated phenanthrene ring structure of rosin-based tricyclic diterpenes was not introduced on their surface, which had a great impact on the initial tack of the back glue, and its adhesion performance on stainless steel plates, aluminum plates, PC plates and PP plates all decreased.

[0128] In Comparative Example 5, SiO2 microspheres were not used, the back glue had poor adhesion performance to the low-surface-energy PP board, and at the same time, the lack of silanol groups on the SiO2 microspheres as crosslinking sites made the adhesive layer prone to cohesive failure during the high-temperature peeling process, resulting in residual glue.

[0129] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of them. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention. Although the specific implementation manners of the present invention have been described above, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made without creative labor by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A high-strength and high-temperature resistant mobile phone adhesive composition, characterized in that: The adhesive composition comprises: polymer polyol, rosin acid modified SiO2 microspheres, curing agent and diluent; Wherein, the polymer polyol is a polymer containing at least one hydroxyl group in the molecular chain, selected from acrylic polyol, polyurethane polyol or polyester polyol; The rosin acid-modified SiO2 microspheres are obtained by reacting SiO2 microspheres activated with surface hydroxyl groups with rosin acid grafted with silane coupling agent; The curing agent is selected from curing agents terminated with isocyanate groups, each curing agent molecule includes at least 2 isocyanate groups, and its terminal structure is: The diluting solvent is selected from any one or a combination of ester or ether solvents.

2. The high-strength and high-temperature-resistant mobile phone adhesive composition according to claim 1, characterized in that: The adhesive composition comprises, by weight: 80-120 parts of acrylic resin, 30-70 parts of diluent solvent, 1-10 parts of rosin acid-modified SiO2 microspheres, and 0.5-5 parts of curing agent.

3. The high-strength and high-temperature-resistant mobile phone adhesive composition according to claim 1, characterized in that: The mass ratio of rosin acid grafted with silane coupling agent to surface hydroxyl activated SiO2 microspheres is (1:0.1)-(1:0.6).

4. The high-strength and high-temperature-resistant mobile phone adhesive composition according to claim 1, characterized in that: The rosin acid grafted with the silane coupling agent is obtained by reacting the rosin acid with an epoxy-containing silane coupling agent; wherein the epoxy-containing silane coupling agent is selected from any one or a combination of 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane or 3-glycidyloxypropylmethyldiethoxysilane; Preferably, the molar ratio of rosin acid to epoxy-containing silane coupling agent is (0.7-0.1):1; More preferably, the molar ratio of rosin acid to epoxy-containing silane coupling agent is (0.8-0.9):

1.

5. The high-strength and high-temperature-resistant mobile phone adhesive composition according to claim 1, characterized in that: The curing agent is selected from a curing agent blocked with tetramethyl meta-xylylene diisocyanate or a curing agent blocked with 3-isopropyl-dimethylbenzyl isocyanate.

6. The high-strength and high-temperature-resistant mobile phone adhesive composition according to claim 1, characterized in that: The ester solvent is selected from any one or a combination of ethyl acetate, butyl acetate or propylene glycol methyl ether acetate, and the ether solvent is selected from any one or a combination of propylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol butyl ether or dipropylene glycol methyl ether.

7. A method for preparing a high-strength and high-temperature resistant mobile phone adhesive, comprising: The high-strength and high-temperature-resistant mobile phone adhesive composition according to any one of claims 1 to 6 is mixed evenly.

8. A cured adhesive layer, obtained by curing the high-strength and high-temperature-resistant mobile phone adhesive composition according to any one of claims 1 to 6 at a temperature of 60-180°C.

9. An adhesive tape comprising: A substrate and a cured adhesive layer, wherein the cured adhesive layer is coated on at least one side or both sides of the substrate; Wherein, the substrate is selected from any one of polyethylene, polypropylene, polyimide or polyester, and the cured adhesive layer is the high-strength and high-temperature resistant mobile phone adhesive composition according to any one of claims 1 to 6; Preferably, the thickness of the substrate does not exceed 150 μm; Preferably, the thickness of the cured adhesive layer does not exceed 50 μm.

10. A method for preparing an adhesive tape, comprising: The high-strength and high-temperature-resistant mobile phone adhesive composition according to any one of claims 1 to 6 is mixed evenly and then coated on at least one side of a film substrate, and cured at a temperature of 60-180° C., and after the curing is completed, a release film is attached to the surface of the cured product; Preferably, the adhesive composition according to any one of claims 1 to 6 is mixed evenly and then coated on both sides of a film substrate, cured at a temperature of 60-180° C., and then attached with a release film to obtain the adhesive composition.

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