A double-sided protective adhesive tape applied to a loudspeaker diaphragm to resist cold and hot cycle impact and a preparation method thereof

Abstract

The application relates to the field of high polymer materials, and discloses a double-sided protective adhesive tape applied to a loudspeaker diaphragm and capable of resisting cold and hot cycle impact. The double-sided protective adhesive tape is prepared by selecting specific types of acrylate hard monomers and acrylate soft monomers, fully utilizing the fact that the hard monomers with higher Tg have better tensile resistance and heat resistance, the soft monomers with lower Tg have better stretchability and low-temperature resistance, and cooperating with three functional monomers of acetyl ethyl acrylate methacrylate, dimethylaminoethyl methacrylate and maleic anhydride, so as to improve the cohesive strength of the polyacrylate parent adhesive through copolymerization and crosslinking of hydroxyl, amino, anhydride and carbon-carbon double bond, and through the selection of the amount of the curing agent in the pressure-sensitive adhesive and the design of the structure of the double-sided protective adhesive tape, the double-sided protective adhesive tape with good peeling strength, creep resistance and cold and hot cycle impact resistance in a wide temperature range is prepared.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a double-sided protective tape for resisting thermal cycling shocks in loudspeaker diaphragms and its preparation method. Background Technology

[0002] A loudspeaker is an electroacoustic device that converts electrical signals into sound signals. More precisely, a loudspeaker works by converting audio electrical power signals within a certain range into audible sound with low distortion and sufficient sound pressure level through transduction. A loudspeaker generally consists of three main parts: a magnetic circuit system (permanent magnet, core, magnetic plate), a vibration system (paper cone, voice coil), and a support and auxiliary system (centering support, frame, padding). (See appendix) Figure 1 The loudspeaker uses a current-carrying conductor as the voice coil. When an audio current signal is input into the voice coil, it acts as a current-carrying conductor. If placed in a fixed magnetic field, according to the principle that a current-carrying conductor moves under the influence of a force in a magnetic field, the voice coil will experience a force proportional to the audio current and whose direction changes with the audio current. This causes the voice coil to vibrate under the influence of the magnetic field, which in turn causes the diaphragm to vibrate. The air in front of and behind the diaphragm also vibrates, thus converting the electrical signal into sound waves and transmitting them to the surroundings. Therefore, the stability of the diaphragm is crucial for ensuring the loudspeaker functions properly. Furthermore, as people's living standards improve, their demands for the sound quality of external loudspeakers are also increasing, requiring low distortion, high sensitivity, and strong directivity. Therefore, to ensure the stability of the diaphragm within the loudspeaker, a layer of tape is applied around the edges of the diaphragm to ensure it adheres tightly to the PC board. However, during the daily use of electronic products with speakers, the diaphragm vibrates continuously during sound production, creating a constant shearing effect on the adhesive tape attached to it. This necessitates that the tape possess good impact resistance, shear resistance, and creep resistance to prevent the adhesive layer on the diaphragm from shifting and affecting sound quality. Furthermore, considering the operating environment of electronic products (-20℃~40℃) and the manufacturing process temperature of speaker components (-20℃~65℃), the tape also needs to maintain good adhesion, impact resistance, and creep resistance over a wide temperature range (-20℃~65℃) and during thermal cycling. Summary of the Invention

[0003] The purpose of this invention is to provide a double-sided protective tape for resisting thermal cycling shock of loudspeaker diaphragms and its preparation method, so as to solve the problems mentioned in the background art.

[0004] This invention provides a double-sided protective tape for resisting thermal cycling shock in loudspeaker diaphragms. The double-sided protective tape consists of a substrate layer and pressure-sensitive adhesive layers located on both sides of the substrate layer. The pressure-sensitive adhesive layers contain polyacrylate masterbatch, tackifying resin, and curing agent. The synthetic raw materials of the polyacrylate masterbatch include, by weight, 30 parts of soft acrylate monomer, 70 parts of hard acrylate monomer, 12-18 parts of functional monomer, 0.2-0.5 parts of initiator, and 130-160 parts of solvent. The functional monomer is composed of ethyl acetoacetate, dimethylaminoethyl methacrylate, and maleic anhydride.

[0005] Furthermore, the mass ratio of the curing agent to the polyacrylate masterbatch and the tackifying resin is (8-10):(500-700):10.

[0006] Furthermore, the polyacrylate masterbatch has a solid content of 40-50%, and the curing agent is a mixture of epoxy resin curing agent and isocyanate curing agent in a mass ratio of 1:1 to 1:1.5.

[0007] Furthermore, the tackifying resin is a mixture of modified terpene resin and modified rosin resin in a mass ratio of 1:1.

[0008] Furthermore, the solvent is a mixture of heptane and butyl acetate in a volume ratio of 2:1.

[0009] Furthermore, the acrylate soft monomer is composed of isobutyl acrylate, n-heptyl acrylate, 2-hydroxypropyl acrylate and isooctadecyl acrylate;

[0010] Furthermore, the acrylate hard monomer is composed of methyl acrylate, methyl methacrylate, tetrahydrofuran acrylate, isobornyl methacrylate, cyclohexyl methacrylate, and dicyclodecane methyl acrylate.

[0011] Furthermore, the mass ratio of ethyl acetoacrylate, dimethylaminoethyl methacrylate, and maleic anhydride in the functional monomer is (3-4):(5-6):(6-8).

[0012] Furthermore, the initiator is a mixture of azobisisobutyronitrile, azobisisoheptanenitrile, and benzoyl peroxide in a mass ratio of 4:4:1.

[0013] Furthermore, the solvent in the raw materials for synthesizing the polyacrylate masterbatch is a mixture of butyl acetate, methylcyclohexane, and ethyl acetate.

[0014] Furthermore, the double-sided protective tape has a thickness of 100μm, the substrate layer is a PET film with a thickness of 6μm-36μm, and the dry adhesive thickness of the pressure-sensitive adhesive layer is 30μm-50μm.

[0015] Furthermore, the substrate layer has a thickness of 12 μm, and the dry adhesive layer has a thickness of 44 μm.

[0016] Furthermore, within the temperature range of -20℃ to 85℃: when the double-sided protective tape is applied to PC board, PET board and SUS board, the 180° peel force is >2500gf / in; more preferably, the 180° peel force is >3500gf / in.

[0017] Furthermore, within the temperature range of -20℃ to 65℃, the double-sided protective tape is bonded to the PC sheet for the housing and the PET sheet for the process surface on both sides, and a 100g weight is hung on it. After 300 cycles in a programmable thermal shock tester, the holding force displacement is <60μm. More preferably, after 300 cycles in a programmable thermal shock tester, the holding force displacement is <45μm.

[0018] This invention also discloses a method for preparing a double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm, comprising the following steps:

[0019] S1. Preparation of mixed monomer solution: Weigh each solvent according to the formula and add it to a four-necked reactor to obtain a mixed solvent. Raise the temperature to 40℃, weigh each acrylate hard monomer according to the formula and add it to the mixed solvent. After stirring and dissolving, add each acrylate soft monomer according to the formula, stir and dissolve and mix evenly. Then add each functional monomer according to the formula, stir for 2 hours, and cool to room temperature to obtain a mixed monomer solution.

[0020] S2. Synthesis of polyacrylate masterbatch: The water bath temperature of the four-necked flask was raised to 55-60℃, and nitrogen gas was introduced for 10 min. Then, 1 / 3 of the total mass of the mixed monomer solution obtained in step S1 was added to the four-necked flask, followed by 1 / 3 of the total mass of the mixed initiator mixture. After reacting for 30 min, 1 / 2 of the total mass of the remaining mixed monomer solution was added. After reacting for another 30 min, the remaining mixed monomer solution was added, and the remaining mixed initiator was added dropwise at a rate of 5 parts by mass / min. The mixture was kept at this temperature for 3 h, and then heating was stopped. The mixture was then refluxed and cooled to room temperature to obtain polyacrylate masterbatch. Nitrogen gas was continuously introduced during the reaction.

[0021] S3. Preparation of pressure-sensitive adhesive: Heat the polyacrylate masterbatch synthesized in step S2 to 45-55℃, add the formula amount of tackifying resin at a stirring speed of 300r / min, continue stirring for 1h, cool to room temperature, then adjust the solid content to 20-30% with solvent, add the formula amount of curing agent, stir at high speed for 30min at a stirring speed of 1000r / min to obtain pressure-sensitive adhesive.

[0022] S4. Preparation of double-sided protective tape: The pressure-sensitive adhesive is coated on both sides of a substrate of predetermined thickness, with a dry adhesive layer thickness of 30μm-50μm. After drying, a release film is then covered on the side of the pressure-sensitive adhesive layer away from the substrate layer to obtain a double-sided protective tape resistant to thermal cycling shock.

[0023] Furthermore, the drying temperature in step S4 is 140℃-160℃, and the coating method is one or more of the following: gravure coating, extrusion coating, and gap coating.

[0024] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0025] (1) In the synthesis of polyacrylate, the pressure-sensitive adhesive obtained when the mass ratio of hard acrylate monomer to soft acrylate monomer is 7:3 generally cannot meet the requirements for high-temperature static shear, high and low temperature peel strength, and impact resistance. However, this invention fully utilizes the high tensile strength and heat resistance of hard monomers with higher Tg and the good extensibility and low-temperature resistance of soft monomers with lower Tg by selecting specific types of hard acrylate monomers and soft acrylate monomers. It also combines three functional monomers: ethyl acetoacetate, dimethylaminoethyl methacrylate, and maleic anhydride. The cohesive strength of the polyacrylate masterbatch was improved through copolymerization and crosslinking of hydroxyl, amino, acid anhydride, and carbon-carbon double bonds. This resulted in a 7:3 mass ratio of acrylate hard monomers to acrylate soft monomers, while the prepared pressure-sensitive adhesive still exhibited good high-temperature static and dynamic shear properties, wide-temperature-range high peel strength, and resistance to thermal cycling shock. By selecting the amount of curing agent added to the pressure-sensitive adhesive and designing the structure of the double-sided protective tape, a double-sided protective tape with good adhesion, creep resistance, and resistance to thermal cycling shock was prepared under both high-temperature (65℃) and low-temperature (-20℃) conditions.

[0026] (2) The double-sided protective tape for thermal shock resistance of the present invention has a 180° peel force of >2500gf / in on the bonding substrates of PC shell, PET film and SUS board in the range of -20℃ to 85℃; in the range of -20℃ to 65℃, the double-sided protective tape is bonded to the PC board for shell and the PET board for process surface on both sides and a 100g weight is hung on it. The holding force displacement is <60μm after 300 cycles in a programmable thermal shock tester. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of how a loudspeaker works.

[0028] Figure 2 This is a schematic diagram of the working environment of a double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to the present invention.

[0029] Figure 3 This is a schematic diagram of a thermal cycling shock test.

[0030] Figure 4 This is a schematic diagram of the temperature cycle for a thermal shock test.

[0031] Figure 5 The rheological properties of a 50 μm substrate-free adhesive film of PSA-1.

[0032] Figure 6 A comparison chart of CTE tests for Tape-1 (top) and Tape-8 (bottom). Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0034] The types and purchasing channels of the tackifying resin and curing agent used in this invention are as follows:

[0035] Modified terpene resin, TSR-1009, Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.;

[0036] Modified rosin resin, TSR-903L, Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.;

[0037] Epoxy resin curing agent, Y-202, Anzo Chemical;

[0038] Isocyanate curing agent, Elepx (Shenyang) Chemical Industry Co., Ltd.

[0039] I. Synthesis of polyacrylate masterbatch (all figures are parts by weight).

[0040] Synthesis example 1:

[0041] S1. Preparation of mixed monomer solution: Weigh 16 parts butyl acetate, 52 parts methylcyclohexane and 82 parts ethyl acetate and add them to a four-necked reactor to obtain a mixed solvent. Raise the temperature to 40℃, weigh 12 parts methyl acrylate, 12 parts methyl methacrylate, 10 parts tetrahydrofuran acrylate, 12 parts isobornyl methacrylate, 20 parts cyclohexyl methacrylate and 4 parts bicyclodecane methyl acrylate and add them to the mixed solvent in sequence. After stirring and dissolving, add 16 parts isooctadecyl acrylate, 8 parts 2-hydroxypropyl acrylate, 3 parts n-heptyl acrylate and 3 parts isobutyl acrylate. Stir and dissolve, mix evenly and then add 3 parts ethyl acetoacetate methacrylate, 5 parts dimethylaminoethyl methacrylate and 6 parts maleic anhydride. Stir for 2 hours and then cool to room temperature to obtain a mixed monomer solution.

[0042] S2. Synthesis of polyacrylate masterbatch: The water bath temperature of the four-necked flask was raised to 60°C, and nitrogen gas was introduced for 10 min. Then, 1 / 3 of the total mass of the mixed monomer solution obtained in step S1 was added to the four-necked flask, followed by 0.04 parts of azobisisobutyronitrile, 0.04 parts of azobisisoheptanenitrile, and 0.01 parts of benzoyl peroxide. After reacting for 30 min, 1 / 2 of the total mass of the remaining mixed monomer solution was added. After reacting for another 30 min, the remaining mixed monomer solution was added, and 0.08 parts of azobisisobutyronitrile, 0.08 parts of azobisisoheptanenitrile, and 0.02 parts of benzoyl peroxide were added dropwise at a rate of 5 parts by mass / min. After maintaining the temperature for 3 h, heating was stopped, and the mixture was then refluxed and cooled to room temperature to obtain polyacrylate masterbatch A-1 with a solid content of 43%. Nitrogen gas was continuously introduced during the reaction.

[0043] Synthesis example 2:

[0044] S1. Preparation of mixed monomer solution: Weigh 16 parts butyl acetate, 52 parts methylcyclohexane and 82 parts ethyl acetate and add them to a four-necked reactor to obtain a mixed solvent. Raise the temperature to 40℃, weigh 14 parts methyl acrylate, 14 parts methyl methacrylate, 14 parts tetrahydrofuran acrylate, 14 parts isobornyl methacrylate, 22 parts cyclohexyl methacrylate and 6 parts bicyclodecane methyl acrylate and add them to the mixed solvent in sequence. After stirring and dissolving, add 20 parts isooctadecyl acrylate, 10 parts 2-hydroxypropyl acrylate, 3 parts n-heptyl acrylate and 3 parts isobutyl acrylate. Stir and dissolve, mix evenly and then add 4 parts ethyl acetoacetate methacrylate, 6 parts dimethylaminoethyl methacrylate and 8 parts maleic anhydride. Stir for 2 hours and then cool to room temperature to obtain a mixed monomer solution.

[0045] S2. Synthesis of polyacrylate masterbatch: The water bath temperature of the four-necked flask was raised to 60°C, and nitrogen gas was introduced for 10 min. Then, 1 / 3 of the total mass of the mixed monomer solution obtained in step S1 was added to the four-necked flask, followed by 0.04 parts of azobisisobutyronitrile, 0.04 parts of azobisisoheptanenitrile, and 0.01 parts of benzoyl peroxide. After reacting for 30 min, 1 / 2 of the total mass of the remaining mixed monomer solution was added. After reacting for another 30 min, the remaining mixed monomer solution was added, and 0.08 parts of azobisisobutyronitrile, 0.08 parts of azobisisoheptanenitrile, and 0.02 parts of benzoyl peroxide were added dropwise at a rate of 5 parts by mass / min. After maintaining the temperature for 3 h, heating was stopped, and the mixture was then refluxed and cooled to room temperature to obtain polyacrylate masterbatch A-2 with a solid content of 48%. Nitrogen gas was continuously introduced during the reaction.

[0046] Comparative Example 1:

[0047] The only difference from Synthesis Example 1 is that 6 parts of dimethylaminoethyl methacrylate and 8 parts of maleic anhydride are added, and ethyl acetoacetate of methacrylate is no longer added. The resulting polyacrylate masterbatch is designated as B-1.

[0048] Comparative Example 2:

[0049] The only difference from Synthesis Example 1 is that 5 parts of ethyl acetoacetate and 9 parts of maleic anhydride are added, and dimethylaminoethyl methacrylate is no longer added. The resulting polyacrylate masterbatch is designated as B-2.

[0050] Comparative Example 3:

[0051] The only difference from Synthesis Example 1 is that 6 parts of ethyl acetoacrylate and 8 parts of dimethylaminoethyl methacrylate are added, and maleic anhydride is no longer added. The resulting polyacrylate masterbatch is designated as B-3.

[0052] Comparative Example 4:

[0053] Taylai TA-776DW (27% solids content, Jiangxi Taylai Polymer Materials Co., Ltd.) adhesive was used as the polyacrylate masterbatch, denoted as B-4.

[0054] II. Preparation of pressure-sensitive adhesive (all figures below are parts by weight).

[0055] The polyacrylate masterbatch in Synthetic Examples 1-2 and Comparative Examples 1-3 was heated to 50°C, and 10 parts of tackifying resin were added while stirring at 300 r / min. After stirring for 1 h, the mixture was cooled to room temperature. The solid content was then adjusted to 27% using a mixed solvent of heptane and butyl acetate in a volume ratio of 2:1 to obtain the corresponding pressure-sensitive adhesive precursor. The specific formulations are shown in Table 1.

[0056] Table 1. Pressure-sensitive adhesive precursor formulation

[0057]

[0058] Weigh the pressure-sensitive adhesive precursor and curing agent according to the formula, stir at high speed for 30 minutes at a stirring speed of 1000 r / min to obtain the corresponding pressure-sensitive adhesive. The specific formula is shown in Table 2.

[0059] Table 2. Pressure-sensitive adhesive formulation

[0060]

[0061] III. Preparation of double-sided protective tape.

[0062] The pressure-sensitive adhesive is applied to both sides of a substrate of a predetermined thickness according to the predetermined dry adhesive thickness, dried at 150°C, and then a release film is covered on the side of the pressure-sensitive adhesive layer away from the substrate layer to obtain a double-sided protective tape resistant to thermal cycling shock. The specific structure of the double-sided protective tape is shown in Table 3.

[0063] Table 3. Structure of Double-Sided Protective Tape

[0064]

[0065]

[0066] experiment

[0067] 1. Thermal Cyclic Shock Holding Strength: A 1-inch square of tape is prepared, with one side attached to PET and the other to PC. A 100g weight is attached to the PC end during testing. The test conditions are thermal cyclic shock from -20℃ to 65℃. One cycle consists of a 23-minute stay at -20℃, a 4-minute rise from -20℃ to 65℃, a 23-minute stay at 65℃, and a 4-minute drop from 65℃ to -20℃. A complete cycle takes approximately 54 minutes. A schematic diagram of the thermal cyclic shock test is attached. Figure 3 and attached Figure 4 .

[0068] Table 4. Test data of cold and hot cycling impact retention force of various double-sided protective tapes

[0069]

[0070] Table 4 shows that during the polymerization of polyacrylate masterbatch, the functional monomers ethyl acetoacrylate, dimethylaminoethyl methacrylate, and maleic anhydride work synergistically. The pressure-sensitive adhesive prepared with a 7:3 mass ratio of hard and soft monomers exhibits superior resistance to thermal cycling shock. When any of these monomers is missing, the resistance to thermal cycling shock of the double-sided protective tape decreases. Furthermore, the tape structure affects the resistance to thermal cycling shock. With different formulations (PSA-1 and PSA-8), the tape structure of 44μm PAS + 12μm PET + 44μm PSA shows the best resistance to thermal cycling shock. Therefore, this structure is considered the optimal tape structure for resistance to thermal cycling shock, exhibiting the best adhesion performance to both PC and PET ends during thermal cycling.

[0071] Table 5. Test data of the retention capacity of Tape-1 under different load conditions during thermal cycling.

[0072]

[0073] As shown in Table 5, the sliding distance of the tape gradually increases with the increase of the thermal cycling time and the weight of the weight. However, when subjected to 300 thermal cycles with a weight of 1000g, the weight on the tape still did not fall off and only slid by 98.6μm, which is sufficient to demonstrate that the double-sided protective tape prepared in this application has excellent resistance to thermal shock.

[0074] 2. 180° peel force: The test was conducted in accordance with the standard test method for peel adhesion of pressure-sensitive tapes, ASTM D3330M-04(2018).

[0075] Table 6. Test data of 180° peel force for various tapes on different substrates (unit: gf / in)

[0076]

[0077]

[0078] As shown in Table 6, the double-sided protective tapes of this application exhibit good adhesion to SUS, PET, and PC. The 180° peel strength values ​​are all high within the temperature range of -20℃ to 85℃, all exceeding 2500 gf / in. Tape-1 and Tape-8 show even better 180° peel strength performance, with values ​​exceeding 3500 gf / in. This indicates that, compared to the pressure-sensitive adhesive precursor Pre-1, the pressure-sensitive adhesive prepared with a mass ratio of epoxy resin curing agent to isocyanate curing agent within the range of 1:1 to 1:1.5 exhibits superior bonding performance. When the mass ratio of epoxy resin curing agent to isocyanate curing agent is greater than 1:1, the insufficient addition of isocyanate curing agent leads to inadequate cross-linking and insufficient cohesion in the pressure-sensitive adhesive, resulting in residual adhesive in the 180° peel strength test.

[0079] 3. Rheological property testing: PSA-1 pressure-sensitive adhesive was made into a 50μm substrate-free tape. This substrate-free tape was then stacked into a 1mm thick, 0.8mm diameter cylinder. A temperature scan was performed at a frequency of 1Hz under conditions ranging from -50℃ to 150℃, with a heating rate of 5℃ / min. The rheological property test data are shown in Table 7. Figure 5 As shown.

[0080] Table 7. Rheological property test data of 50μm substrate-free film of PSA-1

[0081]

[0082] Through Table 7 and Figure 5 The rheological data show that the storage modulus of the tape prepared by the pressure-sensitive adhesive PSA-1 of this invention gradually decreases with increasing temperature. However, even when the temperature rises to 85°C, the fluctuation range of the storage modulus remains very small and still remains within 10. 5 The magnitude indicates that the tape has very strong cohesive properties and excellent performance stability under both high and low temperature conditions.

[0083] 4. CTE Test: The double-sided protective tape was simulated according to actual use. The simulated structure is as follows: the top black plate is the PC shell, the second layer is the double-sided protective tape of the present invention attached to the PC, the third layer is the PET film material attached to the other side of the double-sided protective tape, and the fourth layer is the foam adhesive attached to the other side of the PET film material. Thus, the tape simulating the manufacturing process was obtained.

[0084]

[0085] The tape used in the simulated process was cut into 1-inch x 1-inch squares and attached to a clean PC board. After being rolled with a 2kg roller, it was placed in a hot and cold cycle machine. The temperature range was set to -20℃ (23 min) - 65℃ (23 min) for continuous cycling for 72 hours. Every 24 hours, the tape was removed, its surface condition was observed, and photographs were taken and recorded. The results are as follows: Figure 6 As shown, the double-sided protective tapes used are Tape-1 and Tape-8.

[0086] Generally speaking, after undergoing thermal shock for 24 hours, 48 ​​hours, and 72 hours, the surface of the tape will gradually develop arching and bubbles as the testing time increases, and the longer the time, the more obvious the bubble formation. However, due to... Figure 6 It can be seen that after undergoing 24h, 48h and 72h of thermal shock, the Tape-1 and Tape-8 double-sided protective tapes prepared by this invention did not exhibit any arching at the edges, and no visible bubbles appeared on the adhesive surface. This indicates that the Tape-1 and Tape-8 double-sided protective tapes have excellent resistance to thermal shock, and the thermal cycling shock has almost no impact on the performance of the tape itself. Therefore, the service life of the tape can be greatly extended under extreme conditions.

[0087] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A double-sided protective tape for resisting thermal cycling shock in loudspeaker diaphragms, the double-sided protective tape comprising a substrate layer and pressure-sensitive adhesive layers located on both sides of the substrate layer, the pressure-sensitive adhesive layers comprising polyacrylate masterbatch, tackifying resin and curing agent, characterized in that, The raw materials for synthesizing the polyacrylate masterbatch include, by weight, 30 parts of soft acrylate monomer, 70 parts of hard acrylate monomer, 12-18 parts of functional monomer, 0.2-0.5 parts of initiator, and 130-160 parts of solvent, wherein the functional monomer is composed of ethyl acetoacetate, dimethylaminoethyl methacrylate, and maleic anhydride.

2. The double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 1, characterized in that, The mass ratio of the curing agent to the polyacrylate masterbatch and the tackifying resin is (8-10):(500-700):

10.

3. The double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 1, characterized in that, The polyacrylate masterbatch has a solid content of 40-50%, and the curing agent is a mixture of epoxy resin curing agent and isocyanate curing agent.

4. The double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 1, characterized in that, The tackifying resin is a mixture of modified terpene resin and modified rosin resin in a mass ratio of 1:1; the solvent is a mixture of heptane and butyl acetate in a volume ratio of 2:

1.

5. The double-sided protective tape for resisting thermal cycling shock applied to a speaker diaphragm according to claim 1, characterized in that, The soft acrylate monomers are composed of isobutyl acrylate, n-heptyl acrylate, 2-hydroxypropyl acrylate and isooctadecyl acrylate; the hard acrylate monomers are composed of methyl acrylate, methyl methacrylate, tetrahydrofuran acrylate, isobornyl methacrylate, cyclohexyl methacrylate and dicyclodecane methyl acrylate.

6. The double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 1, characterized in that, The functional monomers are in the mass ratio of ethyl acetoacrylate, dimethylaminoethyl methacrylate and maleic anhydride of (3-4):(5-6):(6-8); the initiator is a mixture of azobisisobutyronitrile, azobisisoheptanenitrile and benzoyl peroxide in a mass ratio of 4:4:

1.

7. The double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 1, characterized in that, The double-sided protective tape has a thickness of 100μm, the substrate layer is a PET film with a thickness of 6μm-36μm, and the dry adhesive thickness of the pressure-sensitive adhesive layer is 30μm-50μm.

8. The double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 7, characterized in that, The substrate layer has a thickness of 12 μm, and the dry adhesive layer has a thickness of 44 μm.

9. A double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 8, characterized in that, The curing agent is a mixture of epoxy resin curing agent and isocyanate curing agent in a mass ratio of 1:1 to 1:1.

5.

10. A double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 8, characterized in that, Within the temperature range of -20℃ to 85℃: when the double-sided protective tape is applied to PC board, PET board and SUS board, the 180° peel force is >2500gf / in.

11. A double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 9, characterized in that, Within the temperature range of -20℃ to 85℃: when the double-sided protective tape is applied to PC board, PET board and SUS board as the substrate, the 180° peel force is >3500gf / in; within the temperature range of -20℃ to 65℃, when the double-sided protective tape is applied to the PC board for the shell and the PET board for the process surface on both sides and a 100g weight is hung on it, the holding force displacement is <45μm after 300 cycles in a programmable thermal shock tester.

12. A method for preparing a double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to any one of claims 1-11, characterized in that, Includes the following steps: S1. Preparation of mixed monomer solution: Weigh each solvent according to the formula and add it to a four-necked reactor to obtain a mixed solvent. Raise the temperature to 40℃, weigh each acrylate hard monomer according to the formula and add it to the mixed solvent. After stirring and dissolving, add each acrylate soft monomer according to the formula, stir and dissolve and mix evenly. Then add each functional monomer according to the formula, stir for 2 hours, and cool to room temperature to obtain a mixed monomer solution. S2. Synthesis of polyacrylate masterbatch: The water bath temperature of the four-necked flask was raised to 55-60℃, and nitrogen gas was introduced for 10 min. Then, 1 / 3 of the total mass of the mixed monomer solution obtained in step S1 was added to the four-necked flask, followed by 1 / 3 of the total mass of the mixed initiator mixture. After reacting for 30 min, 1 / 2 of the remaining total mass of the mixed monomer solution was added, and the reaction was continued for another 30 min. Then, the remaining mixed monomer solution was added, and the remaining mixed initiator was added dropwise at a rate of 5 parts by mass / min. The mixture was kept at this temperature for 3 h, and then heating was stopped. The mixture was then refluxed and cooled to room temperature to obtain polyacrylate masterbatch. Nitrogen gas was continuously introduced during the reaction. S3. Preparation of pressure-sensitive adhesive: The polyacrylate masterbatch synthesized in step S2 is heated to 45-55℃, and the formulated amount of tackifying resin is added while stirring at 300r / min. After stirring continuously for 1 hour, it is cooled to room temperature. Then, the solid content is adjusted to 20-30% with solvent, and the formulated amount of curing agent is added. The mixture is stirred at high speed for 30 minutes at a stirring speed of 1000r / min to obtain the pressure-sensitive adhesive. S4. Preparation of double-sided protective tape: The pressure-sensitive adhesive is coated on both sides of a substrate of predetermined thickness, with a dry adhesive layer thickness of 30μm-50μm. After drying, a release film is then covered on the side of the pressure-sensitive adhesive layer away from the substrate layer to obtain a double-sided protective tape resistant to thermal cycling shock.

13. A method for preparing a double-sided protective tape for resisting thermal cycling shock applied to a loudspeaker diaphragm according to claim 12, characterized in that: The drying temperature in step S4 is 140℃-160℃, and the coating method is one or more of the following: gravure coating, extrusion coating, and gap coating.

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