UV curing hot-melt pressure-sensitive adhesive with high cohesive strength and manufacturing method thereof

Abstract

The invention discloses a UV (ultraviolet) curing hot-melt pressure-sensitive adhesive with high cohesive strength. The UV curing hot-melt pressure-sensitive adhesive comprises butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, a benzophenone derivative containing carbon-carbon double bonds, a solvent, an initiator BPO (benzoyl peroxide) and a nitroxide free radical TEMPO. Butyl acrylate and 2-ethylhexyl acrylate are used as main monomers, acrylic acid is used as a functional monomer, the inherent viscosity characteristic of an acrylic pressure-sensitive adhesive is reserved, the initial binding force with a base material is ensured, and a benzophenone derivative containing carbon-carbon double bonds has the dual functions of photo-initiation activity and cross-linking reaction point positions and can be copolymerized with the monomers to realize UV cross-linking; the nitroxide free radical TEMPO captures free radicals at low temperature and releases free radicals at high temperature, so that the molecular weight distribution is uniform, the initiator BPO and the solvent synergistically guarantee stable polymerization, the product is low in melt viscosity at 130-150 DEG C, small molecular chain segments are few, the molecular weight is large under the combined action of the three, and the hot-melt coating is realized while the cohesion strength is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure sensitive adhesive, in particular to a UV-cured hot melt pressure sensitive adhesive with high cohesive strength and a manufacturing method thereof. BACKGROUND

[0002] Compared with traditional pressure sensitive adhesive coating, hot melt pressure sensitive adhesive has the advantages of high coating efficiency and no solvent volatilization, but traditional hot melt pressure sensitive adhesive does not undergo crosslinking process, and the temperature resistance and cohesive force of the coated product are poor, which has great limitations in application.

[0003] UV-cured acrylic hot melt pressure sensitive adhesive emerges as the times require, and crosslinking is achieved through UV curing after coating, which significantly improves the temperature resistance and cohesive strength. In the prior art, increasing the molecular weight to improve the cohesive strength will increase the coating viscosity, causing coating difficulty. If the amount of UV crosslinking monomer is increased to improve the cohesive strength, the peel strength will be reduced, and the phenomenon of poor bonding with the substrate may occur, so improvement is needed. SUMMARY

[0004] The present application provides a new UV-cured hot melt pressure sensitive adhesive with high cohesive strength to solve the problems of coating difficulty, peel strength reduction, and poor bonding with the substrate in the prior art when increasing the molecular weight or the amount of UV crosslinking monomer to improve the cohesive strength of UV-cured acrylic hot melt pressure sensitive adhesive.

[0005] To solve the above technical problems, the present application realizes the following technical scheme: A UV-cured hot melt pressure sensitive adhesive with high cohesive strength comprises the following components by weight: 25-30 parts of butyl acrylate; 15-20 parts of isooctyl acrylate; 3-5 parts of acrylic acid; 1-2 parts of benzophenone derivative containing carbon-carbon double bond; 45-60 parts of solvent; 0.1-0.3 parts of initiator BPO; 0.1-0.45 parts of nitroxyl radical TEMPO.

[0006] The main monomers are butyl acrylate and isooctyl acrylate, and the functional monomer is acrylic acid. The acrylic pressure-sensitive adhesive retains the inherent adhesive properties of the acrylic pressure-sensitive adhesive, ensuring the initial bonding force with the substrate. The benzophenone derivative containing carbon-carbon double bonds has the dual functions of photo-initiation activity and cross-linking reaction site. The carbon-carbon double bonds in the molecular structure of the benzophenone derivative can be copolymerized with butyl acrylate, isooctyl acrylate and acrylic acid through free radical polymerization, so that the benzophenone structure is directly grafted onto the main chain of the polymer, ensuring that the acrylic pressure-sensitive adhesive can be cross-linked by UV irradiation. The nitroxyl radical TEMPO is 2,2,6,6-tetramethylpiperidine-1-oxyl radical. At a relatively low temperature, it can capture polyacrylate segment radicals during the chain growth stage of polymerization to form polyacrylate segment dormant species. At a relatively high temperature, the polyacrylate segment dormant species can re-form polyacrylate segment radicals to undergo chain growth and chain termination reactions, greatly reducing the proportion of small molecule segments in all segments and ensuring a relatively uniform molecular weight distribution. The initiator BPO is benzoyl peroxide. The initiator BPO and the solvent work together to ensure a stable and controllable polymerization reaction, control the molecular weight, and, under the combined action of the initiator BPO, the solvent and the nitroxyl radical TEMPO, the reaction product has a lower melt viscosity at 130-150°C, fewer small molecule segments and a larger molecular weight, achieving hot melt coating while obtaining high cohesive strength.

[0007] As a preferred embodiment, the solvent includes butyl acetate and xylene in the following proportions by weight: butyl acetate is 40-50 parts, and xylene is 5-10 parts.

[0008] The solvent is composed of butyl acetate and xylene, which can be highly compatible with each monomer and additive, improving the uniformity of the reaction system. The designed proportions of butyl acetate and xylene can balance the evaporation rate and solubility of the solvent, ensuring stable polymerization and efficient removal in subsequent operations, avoiding solvent residues that affect the cohesive strength and performance of the UV-cured hot melt pressure-sensitive adhesive with high cohesive strength.

[0009] As a preferred embodiment, the solvent includes butyl acetate and xylene in the following proportions by weight: butyl acetate is 40-50 parts, and xylene is 5-10 parts.

[0010] 4-acryloyloxybenzophenone or 4-methacryloyloxybenzophenone are both acrylate derivatives and similar in structure to butyl acrylate and isooctyl acrylate, can be well mixed with other components in the system, avoid compatibility problems such as stratification and precipitation, ensure the uniformity of the glue solution, the length of the molecular chain and the steric hindrance are moderate, neither too large to cause diffusion obstruction and affect the uniformity of crosslinking reaction, nor too small to cause the decline of light initiation efficiency, can realize the synergistic and efficient performance of "initiation-crosslinking" in the polymerization and curing process.

[0011] The application also provides a manufacturing method of the UV-cured hot melt pressure-sensitive adhesive with high cohesive strength, which comprises the following steps: S1: uniformly mixing butyl acrylate, isooctyl acrylate, acrylic acid and a benzophenone derivative containing a carbon-carbon double bond to obtain an acrylate monomer mixture, adding the dimethylbenzene and part of the butyl acetate into a reaction kettle, heating to 80 DEG C, then adding part of the initiator BPO and part of the nitroxyl radical TEMPO and reacting for 30 min, and controlling the reaction temperature at 80-85 DEG C during the reaction; S2: uniformly mixing the remaining acrylate monomer mixture, butyl acetate, initiator BPO and nitroxyl radical TEMPO, then adding into a dropping funnel, after the reaction time in step S1 reaches, starting to drop into the reaction kettle and continuing to heat after the dropping is completed; S3: gradually increasing the temperature in the reaction kettle to 130 DEG C, continuing to heat for 8 h after the temperature reaches 130 DEG C, and controlling the heat temperature at 130-135 DEG C; S4: after the reaction is completed, connecting the reaction kettle with a negative pressure filtration device to perform high-temperature negative pressure filtration, and obtaining the UV-cured hot melt pressure-sensitive adhesive with high cohesive strength after the filtration is completed.

[0012] Step S1 is a pre-reaction stage, step S2 is a dropwise polymerization reaction stage, step S3 is a high-temperature continuous reaction stage, and step S4 is a high-temperature negative pressure filtration stage, through the above four steps, the polymerization reaction is precisely controlled, through step S1, a stable polymerization foundation is laid, through step S2, the uneven molecular weight distribution caused by the local high concentration of monomers can be avoided, through step S3, the polymerization reaction can be further improved, and through step S4, residual solvents and impurities can be efficiently removed, the whole process and formula synergistically work to ensure that the UV-cured hot melt pressure-sensitive adhesive with high cohesive strength has a narrow molecular weight distribution and high cohesive strength, and at the same time, the feasibility of hot melt coating is considered.

[0013] As preferred, in the method for manufacturing the UV-cured hot-melt pressure-sensitive adhesive with high cohesive strength, in step S1, the mixture of the butyl acetate and the 1 / 4 acrylate monomer is added into the reaction kettle, nitrogen is continuously introduced into the reaction kettle, heated to 80°C and maintained for 30 min, then part of the initiator BPO and part of the nitroxyl radical TEMPO are added and maintained for 30 min, and the reaction temperature is controlled at 80-85°C.

[0014] The continuous introduction of nitrogen in step S1 can effectively isolate oxygen and avoid the inhibition of oxygen on the free radical polymerization reaction, thereby ensuring the polymerization rate and efficiency. After heating to 80°C and maintaining for 30 min, the initiator BPO and the nitroxyl radical TEMPO are added to make the reaction system temperature uniform and stable, fully mix and dissolve the materials, create optimal conditions for the action of the initiator BPO and the nitroxyl radical TEMPO, and further improve the uniformity of the product molecular weight distribution and the stability of the cohesive strength.

[0015] As preferred, in the method for manufacturing the UV-cured hot-melt pressure-sensitive adhesive with high cohesive strength, in step S1, the weight of the butyl acetate is 20-25 parts, the weight of the initiator BPO is 0.05-0.1 parts, and the weight of the nitroxyl radical TEMPO is 0.05-0.15 parts.

[0016] The butyl acetate is designed to be 20-25 parts, the initiator BPO is designed to be 0.05-0.1 parts, and the nitroxyl radical TEMPO is designed to be 0.05-0.15 parts, which can accurately control the material ratio in the pre-reaction stage. This dosage ratio can ensure the formation of suitable active centers in the pre-step S1 reaction stage, provide a stable basis for the subsequent step S2 drop polymerization, avoid problems such as broadening of the molecular weight distribution and fluctuation of the cohesive strength caused by excessive or insufficient pre-reaction materials, and improve the batch stability of the product.

[0017] As preferred, in the method for manufacturing the UV-cured hot-melt pressure-sensitive adhesive with high cohesive strength, in step S2, the drop time is controlled at 50-100 min, the reaction temperature is controlled at 80-85°C during the drop, and after the drop is completed, the reaction is continued for 60 min, and the reaction temperature is controlled at 80-85°C.

[0018] The drop time of 50-100 min can avoid local intense polymerization caused by rapid addition of monomers, and the temperature control ensures the smooth progress of the free radical polymerization reaction. After the drop is completed, the reaction is continued for 60 min, which can fully involve the unreacted monomers in the polymerization, improve the monomer conversion rate, further optimize the molecular weight distribution and cohesive strength of the product, and ensure the hot-melt coating performance of the UV-cured hot-melt pressure-sensitive adhesive with high cohesive strength.

[0019] As a preferred embodiment, in the above-described method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive, during the high-temperature negative pressure filtration operation in step S4, the negative pressure condition is -0.2 standard atmospheres. During filtration, the temperature is first controlled at 160℃ and maintained for 30 minutes, and then the temperature is controlled at 200℃ and maintained for 5 minutes.

[0020] The aforementioned high-temperature negative pressure filtration conditions can efficiently remove solvents and residual nitric oxide radicals (TEMPO) from the reaction system, preventing residual solvents from affecting the cohesive strength, temperature resistance, and adhesion to the substrate of the high-cohesive UV-curable hot melt pressure-sensitive adhesive, and preventing TEMPO radicals from affecting the UV radiation crosslinking and curing of the UV-curable hot melt pressure-sensitive adhesive. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to specific embodiments, but the present invention is not limited thereto: Example 1

[0022] A high cohesive strength UV-curable hot melt pressure-sensitive adhesive, comprising the following components in parts by weight: 25 parts butyl acrylate; 15 parts of isooctyl acrylate; 3 parts acrylic acid; One part of a benzophenone derivative containing a carbon-carbon double bond; 45 parts solvent; Initiator BPO (benzoyl peroxide) 0.1 parts; 0.1 part of TEMPO nitrogen oxides.

[0023] Preferably, the solvent comprises butyl acetate and xylene in the following parts by weight, wherein butyl acetate is 40 parts and xylene is 5 parts.

[0024] Preferably, the benzophenone derivative containing carbon-carbon double bonds is 4-acryloyloxybenzophenone or 4-methacryloyloxybenzophenone. In this embodiment, the benzophenone derivative containing carbon-carbon double bonds is 4-acryloyloxybenzophenone.

[0025] A method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive includes: S1: The butyl acrylate, isooctyl acrylate, acrylic acid, and benzophenone derivative containing carbon-carbon double bonds are mixed evenly to obtain an acrylate monomer mixture. The xylene, a portion of butyl acetate, and 1 / 4 of the acrylate monomer mixture are added to a reaction vessel, heated to 80°C, and then a portion of initiator BPO and a portion of nitrile radical TEMPO are added and reacted for 30 minutes. The reaction temperature is controlled at 80°C during the reaction. S2: Mix the remaining acrylate monomer mixture, butyl acetate, initiator BPO, and TEMPO nitroxide radicals evenly, and add them to the dropping funnel. After the reaction time in step S1 is reached, start adding them dropwise to the reaction vessel and continue to keep the temperature for reaction after the addition is completed. S3: Gradually raise the temperature inside the reactor to 130℃. After raising it to 130℃, continue to keep the reaction at 130℃ for 8 hours. S4: After the reaction is complete, connect the reactor to a negative pressure filtration device and perform high-temperature negative pressure filtration. After filtration, a UV-curable hot melt pressure-sensitive adhesive with high cohesive strength is obtained.

[0026] Preferably, in step S1, the xylene, a portion of butyl acetate and 1 / 4 acrylate monomer mixture are added to the reactor, nitrogen gas is continuously introduced into the reactor, the temperature is heated to 80°C and maintained for 30 minutes, then a portion of initiator BPO and a portion of nitric oxide radical TEMPO are added to maintain the reaction for 30 minutes, and the reaction temperature is controlled at 80°C.

[0027] Preferably, in step S1, the butyl acetate is 20 parts by weight, the initiator BPO is 0.05 parts by weight, and the nitroxide radical TEMPO is 0.05 parts by weight.

[0028] Preferably, in step S2, the dropping time into the reactor is controlled at 50 min, the reaction temperature is controlled at 80°C, and after the dropping is completed, the reaction continues for 60 min, with the reaction temperature controlled at 80°C.

[0029] Preferably, in step S4, during the high-temperature negative pressure filtration operation, the negative pressure condition is -0.2 standard atmospheres. During filtration, the temperature is first controlled at 160℃ and maintained for 30 minutes, and then the temperature is controlled at 200℃ and maintained for 5 minutes.

[0030] The initiator BPO is benzoyl peroxide, and its molecular formula is:

[0031] The general formulas of butyl acrylate, isooctyl acrylate, acrylic acid, 4-acryloyloxybenzophenone, and 4-methacryloyloxybenzophenone are:

[0032] The nitrogen oxide radical TEMPO is a 2,2,6,6-tetramethylpiperidine-1-oxy radical with the following molecular formula:

[0033] The synthetic equations corresponding to the formation of dormant species of polyacrylate copolymers in steps S1 and S2 are as follows:

[0034] The synthetic equation corresponding to the generation of the polyacrylate copolymer active free radical in step S3 is:

[0035] The synthesis equation corresponding to the formation of the polyacrylate copolymer in step S3 is: Example 2

[0036] The difference between this embodiment and Embodiment 1 is that: a high cohesive strength UV-curable hot melt pressure-sensitive adhesive comprises the following components in parts by weight: 27.5 parts of butyl acrylate; 17.5 parts of isooctyl acrylate; 4 parts acrylic acid; 1.5 parts of benzophenone derivatives containing carbon-carbon double bonds; Solvent: 52.5 parts; Initiator BPO (benzoyl peroxide) 0.2 parts; 0.275 parts of TEMPO nitrogen oxides.

[0037] Preferably, the solvent comprises butyl acetate and xylene in the following parts by weight, wherein butyl acetate comprises 45 parts and xylene comprises 7.5 parts.

[0038] Preferably, the benzophenone derivative containing a carbon-carbon double bond is 4-methacryloyloxybenzophenone.

[0039] A method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive includes: S1: The butyl acrylate, isooctyl acrylate, acrylic acid, and benzophenone derivative containing carbon-carbon double bonds are mixed evenly to obtain an acrylate monomer mixture. The xylene, a portion of butyl acetate, and 1 / 4 of the acrylate monomer mixture are added to a reaction vessel, heated to 80°C, and then a portion of initiator BPO and a portion of nitrile radical TEMPO are added and reacted for 30 minutes. The reaction temperature is controlled at 82.5°C during the reaction. S2: Mix the remaining acrylate monomer mixture, butyl acetate, initiator BPO, and TEMPO nitroxide radicals evenly, and add them to the dropping funnel. After the reaction time in step S1 is reached, start adding them dropwise to the reaction vessel and continue to keep the temperature for reaction after the addition is completed. S3: Gradually increase the temperature inside the reactor to 130℃. After reaching 130℃, continue to maintain the temperature for 8 hours, keeping the temperature at 132.5℃. S4: After the reaction is complete, connect the reactor to a negative pressure filtration device and perform high-temperature negative pressure filtration. After filtration, a UV-curable hot melt pressure-sensitive adhesive with high cohesive strength is obtained.

[0040] Preferably, in step S1, the xylene, a portion of butyl acetate and 1 / 4 acrylate monomer mixture are added to the reactor, nitrogen gas is continuously introduced into the reactor, the temperature is heated to 80°C and maintained for 30 minutes, then a portion of initiator BPO and a portion of nitric oxide radical TEMPO are added to maintain the reaction for 30 minutes, and the reaction temperature is controlled at 82.5°C.

[0041] Preferably, in step S1, the butyl acetate is 22.5 parts by weight, the initiator BPO is 0.075 parts by weight, and the nitroxide radical TEMPO is 0.1 parts by weight.

[0042] Preferably, in step S2, the dropping time into the reactor is controlled at 75 min, the reaction temperature is controlled at 82.5℃, and after the dropping is completed, the reaction continues for 60 min, with the reaction temperature controlled at 82.5℃. Example 3

[0043] The difference between this embodiment and Embodiment 1 is that: a high cohesive strength UV-curable hot melt pressure-sensitive adhesive comprises the following components in parts by weight: 30 parts butyl acrylate; 20 parts of isooctyl acrylate; 5 parts acrylic acid; Two parts of benzophenone derivatives containing carbon-carbon double bonds; 60 parts solvent; Initiator BPO (benzoyl peroxide) 0.3 parts; 0.45 parts of TEMPO nitrogen oxides.

[0044] Preferably, the solvent comprises butyl acetate and xylene in the following parts by weight, wherein butyl acetate is 50 parts and xylene is 10 parts.

[0045] A method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive, the method comprising: S1: The butyl acrylate, isooctyl acrylate, acrylic acid, and benzophenone derivative containing carbon-carbon double bonds are mixed evenly to obtain an acrylate monomer mixture. The xylene, a portion of butyl acetate, and 1 / 4 of the acrylate monomer mixture are added to a reaction vessel, heated to 80°C, and then a portion of initiator BPO and a portion of nitrile radical TEMPO are added and reacted for 30 minutes. The reaction temperature is controlled at 85°C during the reaction. S2: Mix the remaining acrylate monomer mixture, butyl acetate, initiator BPO, and TEMPO nitroxide radicals evenly, and add them to the dropping funnel. After the reaction time in step S1 is reached, start adding them dropwise to the reaction vessel and continue to keep the temperature for reaction after the addition is completed. S3: Gradually increase the temperature inside the reactor to 130℃. After reaching 130℃, continue to keep the reaction at this temperature for 8 hours, and control the temperature at 135℃. S4: After the reaction is complete, connect the reactor to a negative pressure filtration device and perform high-temperature negative pressure filtration. After filtration, a UV-curable hot melt pressure-sensitive adhesive with high cohesive strength is obtained.

[0046] Preferably, in step S1, the xylene, a portion of butyl acetate and 1 / 4 acrylate monomer mixture are added to the reactor, nitrogen gas is continuously introduced into the reactor, the temperature is heated to 80°C and maintained for 30 minutes, then a portion of initiator BPO and a portion of nitric oxide radical TEMPO are added to maintain the reaction for 30 minutes, and the reaction temperature is controlled at 85°C.

[0047] Preferably, in step S1, the butyl acetate is 25 parts by weight, the initiator BPO is 0.1 parts by weight, and the nitroxide radical TEMPO is 0.15 parts by weight.

[0048] Preferably, in step S2, the dropping time into the reactor is controlled at 100 min, the reaction temperature is controlled at 85°C, and after the dropping is completed, the reaction continues for 60 min, with the reaction temperature controlled at 85°C. Example 4

[0049] The high cohesive strength UV-curable hot-melt pressure-sensitive adhesives obtained in Examples 1, 2, and 3 were coated onto PET using a hot-melt coating method. The hot-melt coating conditions were 150°C and a coating blade gap of 100 μm, resulting in a coated sample thickness of 55 μm. After coating, high-pressure mercury lamps were used for curing and crosslinking, yielding samples a, b, and c. The high-pressure mercury lamp power during the curing and crosslinking operation was 400 W. The surface curing energy and curing power of the adhesive layer during curing are shown in the table below.

[0050] Two sets of comparative experiments were set up. The hot melt adhesive used in Comparative Example 1 was BASF's acResin® A260UV product, and the hot melt adhesive used in Comparative Example 2 was Henkel's LOCTITE® DURO-TAK® UV4888NAULTRA product. Comparative Example 1 and Comparative Example 2 were used to obtain sample d and sample e respectively according to the above coating process and light curing process.

[0051] Peel strength and holding power tests were performed on samples a, b, c, d, and e.

[0052] The peel strength test was conducted in accordance with GB / T2792-2014 Test Method for Peel Strength of Adhesive Tapes. The substrate was a standard test steel plate, and the plate was left at room temperature for 20 minutes before the test.

[0053] The holding power test was conducted according to GB / T4851-1998 "Test Method for Holding Power of Pressure-Sensitive Adhesive Tapes". The test was performed at 120℃ for 30 days in a high-temperature holding power test chamber. The tape was placed at room temperature for 24 hours before the test. The load weight was 1 kg. The results of the peel force and holding power tests are shown in the table below.

[0054] The test results above show that the high cohesive strength UV-curable hot melt pressure-sensitive adhesives obtained in Examples 1-3 have a comprehensive application performance that far exceeds that of the comparative examples. They have both good cohesive properties and excellent bonding strength.

[0055] In summary, the above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included within the scope of the present invention.

Claims

1. A high cohesive strength UV-curable hot melt pressure-sensitive adhesive, characterized in that, Includes the following ingredients by weight: 25-30 parts of butyl acrylate; 15-20 parts of isooctyl acrylate; 3-5 parts acrylic acid; One to two parts of a benzophenone derivative containing a carbon-carbon double bond; Solvent 45-60 parts; Initiator BPO 0.1~0.3 parts; Nitrogen oxide free radical TEMPO 0.1~0.45 parts.

2. The high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to claim 1, characterized in that: The solvent comprises butyl acetate and xylene in the following parts by weight, wherein butyl acetate is 40-50 parts and xylene is 5-10 parts.

3. The high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to claim 2, characterized in that: The benzophenone derivative containing a carbon-carbon double bond is 4-acryloyloxybenzophenone or 4-methacryloyloxybenzophenone.

4. A method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to any one of claims 2-3, characterized in that, The manufacturing method includes: S1: The butyl acrylate, isooctyl acrylate, acrylic acid, and benzophenone derivative containing carbon-carbon double bonds are mixed evenly to obtain an acrylate monomer mixture. The xylene, a portion of butyl acetate, and 1 / 4 of the acrylate monomer mixture are added to a reaction vessel, heated to 80°C, and then a portion of initiator BPO and a portion of nitrile radical TEMPO are added and reacted for 30 minutes. The reaction temperature is controlled at 80~85°C during the reaction. S2: Mix the remaining acrylate monomer mixture, butyl acetate, initiator BPO, and TEMPO nitroxide radicals evenly, and add them to the dropping funnel. After the reaction time in step S1 is reached, start adding them dropwise to the reaction vessel and continue to keep the temperature for reaction after the addition is completed. S3: Gradually raise the temperature inside the reactor to 130℃. After raising it to 130℃, continue to keep the reaction at this temperature for 8 hours, with the temperature controlled at 130~135℃. S4: After the reaction is complete, connect the reactor to a negative pressure filtration device and perform high-temperature negative pressure filtration. After filtration, a UV-curable hot melt pressure-sensitive adhesive with high cohesive strength is obtained.

5. The method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to claim 4, characterized in that: In step S1, the xylene, a portion of butyl acetate and 1 / 4 acrylate monomer mixture are added to the reactor, nitrogen gas is continuously introduced into the reactor, the temperature is heated to 80°C and maintained for 30 minutes, then a portion of initiator BPO and a portion of nitric oxide radical TEMPO are added to maintain the reaction for 30 minutes, and the reaction temperature is controlled at 80~85°C.

6. The method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to claim 5, characterized in that: In step S1, the butyl acetate is 20-25 parts by weight, the initiator BPO is 0.05-0.1 parts by weight, and the nitroxide radical TEMPO is 0.05-0.15 parts by weight.

7. The method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to claim 4, characterized in that: In step S2, the dropping time is controlled at 50-100 min and the reaction temperature is controlled at 80-85℃. After the dropping is completed, the reaction continues for 60 min and the reaction temperature is controlled at 80-85℃.

8. The method for manufacturing a high cohesive strength UV-curable hot melt pressure-sensitive adhesive according to claim 4, characterized in that: In step S4, during the high-temperature negative pressure filtration operation, the negative pressure condition is -0.2 standard atmospheres. During filtration, the temperature is first controlled at 160℃ and maintained for 30 minutes, and then the temperature is controlled at 200℃ and maintained for 5 minutes.

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