Impact-resistant substrate-adhesive-free protective adhesive tape and preparation method thereof

Abstract

The invention relates to the technical field of pressure-sensitive adhesives, in particular to an impact-resistant substrate-adhesive-free protective adhesive tape and a preparation method thereof. The adhesive comprises a mixed solvent, a hard monomer, a soft monomer, a functional monomer, an initiator, tackifying resin and a curing agent, and the mass ratio of the hard monomer to the soft monomer is 4: 6; the adhesive tape prepared by the invention has better anti-buffering and energy-absorbing effects, also has certain flexibility, namely compression performance, and cannot cause physical damage to a used part due to over-rigidity of the adhesive tape so as to face large-amplitude impact influence or small-amplitude long-time impact influence in a use scene.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive technology, specifically to an impact-resistant substrate-free adhesive protective tape and its preparation method. Background Technology

[0002] Adhesive tape is widely used in the assembly of components and in daily life. It is an indispensable material in industrial manufacturing and electronic assembly. With the development of technology, the performance requirements for adhesive tape are getting higher and higher. Especially in the current electronic communication industry, for electronic devices such as mobile phones and tablets with precision electronic components, due to their high price and precision requirements, and with the emergence of more and more outdoor sports, people have put forward more and more applicability requirements for these convenient and portable electronic devices, and their impact resistance is particularly outstanding.

[0003] With the development of technology, people are increasingly inclined to use large-screen devices, whether mobile phones or tablets. The screen size relative to the overall device has become increasingly larger, which places higher demands on the display modules of mobile phones and tablets. This presents new challenges for our mobile phone display module tape suppliers.

[0004] The display module structure behind the mobile phone screen needs to be reinforced with a buffer area between it and the control circuit. The purpose of the buffer area is to prevent the display module from being damaged by the impact when the front or back of the phone is subjected to external force. Therefore, the buffering performance of the buffer area material is particularly important.

[0005] Previously, most mobile phones and tablets used foam as the cushioning material due to its porous and resilient properties. For example, Chinese patent CN107502217A discloses an ultra-thin mobile phone screen foam tape, which consists of a PU elastic layer, a printed layer, a PET layer, and an acrylic pressure-sensitive adhesive layer. The printed layer is set on the upper surface of the PET layer, and the acrylic pressure-sensitive adhesive layer is coated on the lower surface. The printed layer, PET layer, and acrylic pressure-sensitive adhesive layer form a mesh structure. The PU elastic layer is set on the upper surface of the mesh structure and is formed by filling foam material.

[0006] However, it has been found that foam is prone to damage and breakage after repeated use, which seriously affects its ability to continue to perform its cushioning function. Therefore, a new solution with softness and toughness is used to replace foam, so as to replace it in performing the cushioning function and effectively avoid material breakage caused by long-term compression.

[0007] To address the above problems, this invention provides an impact-resistant substrate-free adhesive protective tape and its preparation method. Summary of the Invention

[0008] The purpose of this invention is to provide an impact-resistant, substrate-free adhesive protective tape and its preparation method, so as to solve the problems mentioned in the background art.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0010] A method for preparing an impact-resistant, substrate-free adhesive protective tape, comprising the following substances:

[0011] Mixed solvents, hard monomers, soft monomers, functional monomers, initiators, tackifying resins, and curing agents;

[0012] The mass ratio of hard monomers to soft monomers is 4:6.

[0013] The mixed solvent comprises ethyl acetate, butyl acetate, and n-heptane in a mass ratio of 5:2:1.

[0014] More preferably, the hard monomer includes at least one of methyl acrylate, furan acrylate, isobornyl methacrylate, cyclohexyl methacrylate, dicyclodecane methyl acrylate, and methyl methacrylate.

[0015] More preferably, the soft monomer is at least one of isobutyl acrylate, n-heptyl acrylate, β-hydroxypropyl methacrylate, and 2-ethylhexyl acrylate.

[0016] More preferably, the functional monomer is at least one of ethyl acetoacrylate, dimethylaminoethyl methacrylate, maleic anhydride, methyl methacrylate, methacrylamide, and hydroxyethyl acrylate.

[0017] More preferably, the initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and benzoyl peroxide.

[0018] Ideally, the tackifying resin is a modified terpene resin, a modified rosin resin, or a mixture of the two; the curing agent is an isocyanate.

[0019] In a more optimized manner, the preparation process includes the following steps:

[0020] S1, Preparation of mixed monomers

[0021] Add the mixed solvent to the four-necked reactor, adjust the temperature to 65°C, and add a fixed amount of hard monomer, soft monomer and mixed monomer to the mixed solvent; stir for 2 hours and then cool to room temperature; the solid content of the mixed monomer is 45% and the total number of parts is 90.

[0022] S2, Preparation of acrylic copolymer

[0023] Using a 1L four-necked flask, adjust the water bath temperature to 55-60℃, purge with a protective gas such as nitrogen for 10 minutes, take out 30 portions of the mixed monomer solution obtained in step S1, and add 0.5 portions of azobisisobutyronitrile, 0.5 portions of azobisisoheptanenitrile, and 0.1 portions of benzoyl peroxide as initiators.

[0024] After reacting for 30 minutes, the remaining mixed monomers were added in two separate batches, with 30 portions of the mixed monomers added each time and reacting for 30 minutes each time.

[0025] After the last 30 parts of the mixed monomers were added, 1 part of azobisisobutyronitrile, 1 part of azobisisoheptanenitrile, and 0.2 parts of benzoyl peroxide were added. The temperature was raised to 65-70°C, and the dropping rate was controlled at 5 parts / 1 min. The temperature was maintained for 3 hours and then the heating was stopped. During this process, a protective gas was continuously introduced. The mixture was then refluxed and cooled to room temperature. At this point, the solid content was 43%.

[0026] S3. Pour the product obtained in step S2 back into the reactor, adjust the temperature to 50-60℃, stir at 300r / min, add 10 parts of modified terpene resin and modified rosin resin that have been dissolved in butyl acetate to the reactor, stir continuously for 1 hour, and then cool to room temperature to obtain polyacrylic acid adhesive.

[0027] S4. Take the polyacrylic acid adhesive obtained in step S3, use heptane and butyl ester as solvents, adjust the solid content to 20-30%, stir at 1000 r / min for 30 min, add a quantitative curing agent and epoxy resin, stir at 1000 r / min for 30 min to obtain the finished adhesive.

[0028] In a more optimized manner, the hard monomers include 5 parts methyl acrylate, 5 parts furan acrylate, 5 parts isobornyl methacrylate, 10 parts cyclohexyl methacrylate, 2 parts bicyclodecane methyl acrylate, and 3 parts methyl methacrylate.

[0029] Soft monomers include ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate.

[0030] The functional monomers include 1.5 parts ethyl acetoacrylate, 2.5 parts dimethylaminoethyl methacrylate, 3 parts maleic anhydride, and 5 parts methyl methacrylate;

[0031] The mixed solvents consist of 12.5 parts butyl acetate, 6.25 parts n-heptane, and 31.25 parts ethyl acetate.

[0032] In a more optimized manner, isocyanate accounts for 0.4-1.0% of the total mass of the adhesive; epoxy resin accounts for 0.4-2.0% of the total mass of the adhesive; and functional resins with different softening points are also added in step S4, accounting for 0.4-1.0% of the total mass of the adhesive.

[0033] The present invention also provides an impact-resistant substrate-free adhesive protective tape, which is prepared using any of the above-described methods for preparing impact-resistant substrate-free adhesive protective tape.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0035] (1) In this invention, the added soft and hard monomers contain aliphatic groups, hydroxyl groups and carbon-carbon double bonds. The hard monomers have better tensile strength and heat resistance due to their higher Tg, while the soft monomers have better extensibility and low-temperature resistance due to their lower Tg. Therefore, the copolymer has the characteristics of both, and its performance at both low and high temperatures is good. In order to reduce the Tg of the generated masterbatch, the original soft and hard monomers with lower Tg are selected in the formulation design of the synthesis. The ratio of soft monomers to hard monomers is specially adjusted during the synthesis to increase the proportion of soft monomers to a certain extent, thereby reducing the Tg of the synthesized masterbatch. At the same time, the selected monomers have more unsaturated chemical bonds and free radicals. The copolymer free radical polymerization crosslinks, which increases the polymerization density of the copolymer, thereby increasing the cohesive strength of the masterbatch. To a certain extent, when the masterbatch is subjected to a certain energy impact, it can effectively distribute the impact energy evenly to a larger stress area, thereby increasing the impact resistance of the masterbatch.

[0036] (2) In this invention, the tape has good anti-buffering and energy absorption properties, and also has a certain degree of softness and compression performance. It is not too rigid and will cause physical damage to the part in use, so as to withstand the impact of large-scale impact or small-scale long-term impact in the use scenario.

[0037] (3) In this invention, the tape has certain initial tack and good adhesion properties, ensuring that it does not fall off or delaminate when it is adhered to copper foil and mesh tape. In use, it can adhere to the copper foil with adhesive on one side and the mesh tape on the other side.

[0038] (4) The tape prepared in this invention has good high temperature and low temperature resistance, so as to realize the normal use of the tape in high temperature or low temperature environment. Attached Figure Description

[0039] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0040] Figure 1 A comparison chart of the compressibility properties of adhesives;

[0041] Figure 2 The rheological properties of three different adhesives in the examples are shown.

[0042] Figure 3 This is a schematic diagram simulating orange peel texture;

[0043] Figure 4 The images show the results of the orange peel texture simulation experiments in Examples 11, 14, and 15. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0045] In order to address several key performance aspects of the adhesive tape mentioned in this invention, the preparation method of this invention is designed as follows:

[0046] 1. To ensure that the tape has good cushioning and energy absorption properties, the material itself must be soft and have a good ability to deform, so as to convert the impact energy into internal energy. Therefore, it is necessary to select a soft masterbatch with a low Tg for experimental design.

[0047] 2. The colloid needs to be both soft and have a certain degree of rigidity, so that the applied force can be evenly distributed across the entire surface of the colloid, thereby increasing the stress area and achieving a buffering effect.

[0048] 3. To meet the requirement of cushioning performance of the tape, it is necessary to adjust and develop the structure of the tape to achieve the best absorption capacity.

[0049] 4. The tape needs to have certain initial tack and peel strength properties during use to ensure that it has a peel strength of 1500gf / in against SUS at high temperature, room temperature and low temperature.

[0050] This invention designs several embodiments to prepare different tapes to verify their performance, and the materials used are shown in Table 1.

[0051] Table 1. Material list used in each embodiment

[0052]

[0053]

[0054] The preparation of the acrylic adhesive in this invention includes the following steps:

[0055] S1, Preparation of mixed monomers

[0056] A mixed solvent (5 parts butyl acetate, 17.5 parts methylcyclohexane, and 27.5 parts ethyl acetate) was added to a four-necked reactor, and the temperature was adjusted to 65°C. 5 parts methyl acrylate, 5 parts furan acrylate, 5 parts isobornyl methacrylate, 10 parts cyclohexyl methacrylate, 2 parts bicyclodecane methyl acrylate, 3 parts methyl methacrylate, 1.5 parts ethyl acetoacetate, 2.5 parts dimethylaminoethyl methacrylate, 3 parts maleic anhydride, and 5 parts methyl methacrylate were added to the mixed solvent. After stirring for 2 hours, the mixture was cooled to room temperature. The solid content of the mixed monomers was approximately 45%, with a total of 90 parts.

[0057] S2, Preparation of acrylic copolymer

[0058] Using a 1L four-necked flask, adjust the water bath temperature to 55-60℃ and purge with a protective gas such as nitrogen for 10 minutes. Remove the flask and add 30 parts of the monomer solution from step one, along with 0.5 parts of azobisisobutyronitrile, 0.5 parts of azobisisoheptanenitrile, and 0.1 parts of benzoyl peroxide. React with the initiator for 30 minutes. Then, add the remaining 60 parts of the mixed monomer solution in two batches of 30 parts each, reacting for 30 minutes each time. After adding the last 30 parts, add 1 part of azobisisobutyronitrile, 1 part of azobisisoheptanenitrile, and 0.2 parts of benzoyl peroxide. Raise the temperature to 65-70℃ and control the dropping rate at 5 parts / 1 minute. Keep warm for 3 hours and then stop heating. During this process, continue to purge with a protective gas. Then, reflux and cool to room temperature. At this point, the solid content is approximately 43%.

[0059] S3. Pour the liquid obtained in step S2 back into the reactor, adjust the temperature to 50-60℃, stir at 300r / min, add 10 parts of modified terpene resin and modified rosin resin that have been dissolved in butyl acetate to the reactor, stir continuously for 1 hour, and then cool to room temperature to obtain polyacrylic acid adhesive.

[0060] After the polyacrylic adhesive is prepared, a curing agent and epoxy resin are added to prepare the thermal shock resistant adhesives in Examples 1-7. The specific formulations are shown in Table 2.

[0061] In Examples 1-7, polyacrylic acid adhesives (A), (B), (C), (D), (E), (F), and (G) with a TG below -30 degrees Celsius were selected. The main differences between them are their different Tg points and different molecular weights. The solid content of the solution was adjusted to 20-30% using heptane and butyl ester (heptane:butyl ester volume ratio 2:1) as solvents. After stirring at high speed (1000 r / min) for 30 min, 0.4-1.0% isocyanate (H) and 0.4-2.0% epoxy resin (I) by weight of the adhesive were added, and the mixture was stirred at high speed (1000 r / min) for 30 min.

[0062] Table 2. Material list for Examples 1-7

[0063] project adhesive Isocyanate (H) Epoxy Resin (I) Example 1 A 4 2 Example 2 B 4 1 Example 3 C 6 2 Example 4 D 6 1 Example 5 E 4 2 Example 6 F 4 2 Example 7 G 6 1

[0064] Next, Examples 8-11 were designed, using a self-synthesized polyacrylic acid adhesive (A). Heptane and butyl ester (heptane:butyl ester volume ratio 2:1) were used as solvents to adjust the solid content of the solution to 20-30%. After stirring at high speed (1000 r / min) for 30 min, 0.4-1.0% isocyanate (H) and 0.4-2.0% epoxy resin (I) were added, along with 10-40% resins with different softening points (J softening point 125℃) (K softening point 100℃) (L softening point 75℃) by weight of the adhesive. The mixture was stirred at high speed (1000 r / min) for 30 min. The specific mass values ​​are shown in Table 3.

[0065] Table 3. Material list for Examples 8-11

[0066] project Adhesive (A) Isocyanate (H) Epoxy Resin (I) Resin (J) Resin (K) Resin (L) Example 8 1000 4 2 20 10 0 Example 9 1000 4 2 15 0 10 Example 10 1000 4 2 0 10 15 Example 11 1000 4 2 0 0 15

[0067] Next, Examples 12-17 were designed, using polyacrylic acid adhesives (A)(B)(C)(D)(E)(F)(G) with a TG value below -30 degrees Celsius. The solid content of the solution was adjusted to 20-30% using heptane and butyl ester (heptane:butyl ester volume ratio 2:1) as solvents. After stirring at high speed (1000 r / min) for 30 min, 0.4-1.0% isocyanate (H) and 0.4-2.0% epoxy resin (I) by weight of the adhesive were added, along with 0.4-1.0% resins (J)(K)(L) with different softening points by weight of the adhesive. The mixture was stirred at high speed (1000 r / min) for 30 min. The specific mass values ​​are shown in Table 4.

[0068] Table 4. Material list for Examples 12-17

[0069] project adhesive Isocyanate (H) Epoxy Resin (I) Resin (J) Resin (K) Resin (L) Example 9 A 4 2 15 0 10 Example 13 C 4 2 15 0 10 Example 14 D 4 2 15 0 10 Example 11 A 4 2 0 0 15 Example 16 C 4 2 0 0 15 Example 17 D 4 2 0 0 15

[0070] After obtaining the tapes prepared in Examples 1-17, it is necessary to perform performance testing and verification.

[0071] I. Buffer performance test and peel force test of Examples 1-7.

[0072] Buffer performance testing method one:

[0073] A falling ball testing machine, model XET-U0T80A, was used. During the experiment, a 4g ball was dropped freely from a height of 10cm and impacted the machine's sensor probe. The machine read the induced pressure at this moment and recorded it as F1. A 100μm substrate-free adhesive tape manufactured by us was placed on the machine's sensor probe, and a 4g ball was dropped freely from a height of 10cm and impacted the adhesive surface of the sensor probe. The machine read the induced pressure at this moment and recorded it as F2. Finally, the absorption rate was calculated as (F1-F2) / F2*100% as the point impact absorption rate of this tape. Ten tests were conducted on each sample, and the average value was taken as the point impact test data for that sample.

[0074] Buffer performance testing method two:

[0075] The impact performance of the test points was tested using Fuji pressure testing film. Before testing, a substrate-free adhesive was attached to copper foil tape on one side and mesh tape on the other, simulating the structural state of the actual product, forming a 3-layer composite structure sample. The temperature and humidity of the test environment were maintained at 25℃±3 and 50%RH±5. During the test, the composite structure sample was attached to the pressure-sensitive paper, which was then placed on a marble test platform. A 2g ball was dropped freely from a height of 10cm onto the copper foil surface of the composite structure sample. Due to the impact force, the pressure-sensitive paper would display a corresponding color. The displayed color was scanned and analyzed in the computer system software. The corresponding pressure value was read based on the color difference.

[0076] The results of the buffer performance test are shown in Table 5, and the results of the peel force test are shown in Table 6.

[0077] Table 5. Test results of the cushioning performance of the tapes prepared in Examples 1-7

[0078] project Thickness / μm Average pressure / MPa Example 1 100 32.6 Example 2 100 35.6 Example 3 100 32.7 Example 4 100 32.4 Example 5 100 34.7 Example 6 100 36.2 Example 7 100 32.5

[0079] Table 6 shows the peel strength test results of the tapes prepared in Examples 1-7.

[0080]

[0081]

[0082] As can be seen, Examples 1-7 correspond to adhesives formed through different synthesis routes. When the same formulation of the adhesives was scraped, the impact performance and corresponding peel force were verified. It can be seen that Examples 1, 3, 4 and 7 all showed good impact performance, indicating that the tape has good performance absorption. The other examples all showed impact performance above 34 MPa, which all showed poor energy absorption effect.

[0083] Simultaneous observation of the peel force data shows that the high temperature in Example 7 exhibits a significant disadvantage in the bonding force between PET and copper foil, which is clearly not in line with our original design intention. Although the high temperature bonding force performance of Examples 1, 3, and 4 is not very outstanding, the initial performance is not bad. Further research can be conducted on their bonding force performance between PET and copper foil by adjusting the formula.

[0084] II. Buffer performance test of Examples 8-11, and high temperature performance test of PET and copper foil.

[0085] The results of the buffer performance test are shown in Table 7, and the results of the peel force test are shown in Table 8.

[0086] Table 7 shows the test results of the cushioning performance of the tapes prepared in Examples 8-11.

[0087] project Thickness / μm Average pressure / MPa Example 8 100 33.7 Example 9 100 32.6 Example 10 100 32.3 Example 11 100 33.5

[0088] Table 8 shows the peel strength test results of the tapes prepared in Examples 8-11.

[0089]

[0090] Therefore, this experiment verified the effect of the formulation on the performance of the cushioning tape by adding four different values ​​and adjusting the proportion of the same adhesive A. The data shows that the formulation results of Examples 9 and 11 verify that by adding different proportions of resin, the room temperature and high temperature bonding performance of the film to PET and copper foil can be further improved without affecting the cushioning performance of the film as much as possible, and a better bonding level can be achieved.

[0091] III. Buffer performance tests of Examples 12-17, and high-temperature performance tests on PET and copper foil.

[0092] The results of the buffer performance test are shown in Table 9, and the results of the peel force test are shown in Table 10.

[0093] Table 9 shows the test results of the cushioning performance of the tapes prepared in Examples 9-15.

[0094] project Thickness / μm Average pressure / MPa Example 9 100 32.6 Example 11 100 33.5 Example 12 100 34.2 Example 13 100 32.4 Example 14 100 33.1 Example 15 100 34.7

[0095] Table 10 shows the peel strength test results of the tapes prepared in Examples 9-15.

[0096]

[0097] Finally, the same formulation design was carried out for three different adhesives A, C, and D. The experimental results show that the energy absorption performance of different adhesives has different effects on the addition of different resins. Through experimental data analysis, although the addition of resin can greatly enhance the bonding force of the film to PET and CU to a certain extent, it has a greater impact on impact. On average, Example 11 can significantly improve its bonding force to PET and CU while slightly affecting the impact performance, making it a superior impact-resistant buffer film.

[0098] IV. Comparison of the rheological properties of adhesive (A) and adhesives (C) and (D).

[0099] The rheological properties of three different adhesives are as follows: Figure 2 As shown, all three adhesives have low Tg points, but their storage modulus at room temperature varies greatly, and their storage modulus at high temperature also shows significant differences. This leads to significant differences in the loss factors of the three adhesives. Combining the final impact data and bonding force data, it is not the case that a higher or lower modulus will necessarily result in better adhesive performance. Rather, we need to consider the loss modulus or loss factor after the storage modulus reaches a certain point in order to find the best adhesive suitable for the performance of the buffer film.

[0100] V. Comparison of the compressibility properties of adhesive (A) and adhesives (C) and (D).

[0101] Analyzing the compression properties of Examples 11, 16 and 17, the colloids of Examples 11 and 16 have good compressive strength, while the compressive strength of Example 17 is relatively poor. Under the same pressure, Example 17 exhibits more deformation. The colloid is too soft, and when subjected to impact, the deformation is greater, which may pose a greater risk of glue overflow and leakage.

[0102] Comparison of high-temperature orange peel texture phenomenon in Examples 11, 14, and 15.

[0103] Orange peel texture test method: First, apply copper foil tape to one side of the adhesive film, then apply the non-mesh side of the grid adhesive to the other side of the adhesive film; finally, apply the grid side of the grid adhesive to the glass plate; place it at 85℃ and 85%RH for 5 days.

[0104] Observation: Use a linear light source to project a photograph onto the surface of the copper foil, record the reflection of the copper foil, and observe the orange peel texture with the naked eye.

[0105] Results of orange peel texture simulation experiment as follows Figure 3-4As shown in the experimental results, the orange peel texture simulation result of Example 11 is characterized by rough edges. In contrast, the edges of the adhesive in Examples 14 and 15 appear smooth. This indicates that the pressure-sensitive adhesive of Example 11 has poor high-temperature resistance when placed under high-temperature conditions. The creep effect inside the adhesive is more obvious at high temperatures. The self-creep inside the adhesive easily forms orange peel texture of varying thickness on the adhesive film, which is particularly obvious when light shines on the surface of the copper foil.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0107] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an impact-resistant, substrate-free adhesive protective tape, characterized in that, Including the following substances: Mixed solvents, hard monomers, soft monomers, functional monomers, initiators, tackifying resins, and curing agents; The mass ratio of hard monomers to soft monomers is 4:

6. The mixed solvent comprises ethyl acetate, butyl acetate, and n-heptane in a mass ratio of 5:2:

1.

2. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that: The hard monomer includes at least one of methyl acrylate, furan acrylate, isobornyl methacrylate, cyclohexyl methacrylate, dicyclodecane methyl acrylate, and methyl methacrylate.

3. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that: The soft monomer is at least one of isobutyl acrylate, n-heptyl acrylate, β-hydroxypropyl methacrylate, and 2-ethylhexyl acrylate.

4. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that: The functional monomer is at least one of ethyl acetoacrylate, dimethylaminoethyl methacrylate, maleic anhydride, methyl methacrylate, methacrylamide, and hydroxyethyl acrylate.

5. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that: The initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and benzoyl peroxide.

6. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that: The tackifying resin is a modified terpene resin, a modified rosin resin, or a mixture of the two; the curing agent is an isocyanate.

7. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that, Includes the following steps: S1, Preparation of mixed monomers Add the mixed solvent to the four-necked reactor, adjust the temperature to 65°C, and add a fixed amount of hard monomer, soft monomer and mixed monomer to the mixed solvent; stir for 2 hours and then cool to room temperature; the solid content of the mixed monomer is 45% and the total number of parts is 90. S2, Preparation of acrylic copolymer Using a 1L four-necked flask, adjust the water bath temperature to 55-60℃, purge with a protective gas such as nitrogen for 10 minutes, take out 30 portions of the mixed monomer solution obtained in step S1, and add 0.5 portions of azobisisobutyronitrile, 0.5 portions of azobisisoheptanenitrile, and 0.1 portions of benzoyl peroxide as initiators. After reacting for 30 minutes, the remaining mixed monomers were added in two separate batches, with 30 portions of the mixed monomers added each time and reacting for 30 minutes each time. After the last 30 parts of the mixed monomers were added, 1 part of azobisisobutyronitrile, 1 part of azobisisoheptanenitrile, and 0.2 parts of benzoyl peroxide were added. The temperature was raised to 65-70°C, and the dropping rate was controlled at 5 parts / 1 min. The temperature was maintained for 3 hours and then the heating was stopped. During this process, a protective gas was continuously introduced. The mixture was then refluxed and cooled to room temperature. At this point, the solid content was 43%. S3. Pour the product obtained in step S2 back into the reactor, adjust the temperature to 50-60℃, stir at 300r / min, add 10 parts of modified terpene resin and modified rosin resin that have been dissolved in butyl acetate to the reactor, stir continuously for 1 hour, and then cool to room temperature to obtain polyacrylic acid adhesive. S4. Take the polyacrylic acid adhesive obtained in step S3, use heptane and butyl ester as solvents, adjust the solid content to 20-30%, stir at 1000 r / min for 30 min, add a quantitative curing agent and epoxy resin, stir at 1000 r / min for 30 min to obtain the finished adhesive.

8. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 7, characterized in that: The hard monomer comprises 5 parts methyl acrylate, 5 parts furan acrylate, 5 parts isobornyl methacrylate, 10 parts cyclohexyl methacrylate, 2 parts bicyclodecane methyl acrylate, and 3 parts methyl methacrylate. The soft monomer comprises 10 parts ethyl acrylate, 15 parts butyl acrylate, and 20 parts 2-ethylhexyl acrylate. The functional monomers include 1.5 parts ethyl acetoacrylate, 2.5 parts dimethylaminoethyl methacrylate, 3 parts maleic anhydride, and 5 parts methyl methacrylate. The mixed solvent comprises 12.5 parts butyl acetate, 6.25 parts n-heptane, and 31.25 parts ethyl acetate.

9. The method for preparing an impact-resistant substrate-free adhesive protective tape according to claim 7, characterized in that: The isocyanate accounts for 0.4-1.0% of the total mass of the adhesive; the epoxy resin accounts for 0.4-2.0% of the total mass of the adhesive; and in step S4, functional resins with different softening points are also added, accounting for 0.4-1.0% of the total mass of the adhesive.

10. The impact-resistant substrate-free adhesive protective tape according to claim 1, characterized in that: It is prepared using any one of the methods for preparing impact-resistant substrate-free adhesive protective tape as described in claims 1 to 9.

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