Polyurethane-based ultraviolet light-induced strippable adhesion-reducing glue and method of making same

Abstract

The polyurethane-based ultraviolet light-induced peelable adhesion-reducing glue and its preparation method are prepared from a polyurethane acrylate prepolymer-based glue, a curing agent, a photoinitiator and a diluent. The isocyanate intermediate and the polyacrylic acid resin are modified by a chemical grafting method to prepare the polyurethane acrylate prepolymer as the base glue. Compared with the traditional physical blending method, the problem of poor component compatibility and insufficient crosslinking degree is effectively solved, the glue layer has excellent mechanical properties of polyurethane and efficient photocuring characteristics of acrylate, and the problem of device damage caused by insufficient adhesion of the glue layer in the wafer processing process is avoided. By optimizing the optimal addition ratio of each component, the prepared adhesion-reducing glue has high initial peeling strength, can provide stable temporary fixing effect for wafer processing, the peeling strength is significantly reduced after UV irradiation, the adhesion is quickly lost, and there is no residual glue after peeling.

Description

Technical Field

[0001] This invention belongs to the technical field of semiconductor chip processing materials, specifically relating to polyurethane-based ultraviolet photosensitive peelable adhesives. This invention also relates to a method for preparing polyurethane-based ultraviolet photosensitive peelable adhesives. Background Technology

[0002] In the manufacturing process of precision components such as chips and wafers, temporary bonding and fixation are core technologies supporting the smooth progress of cutting, grinding, and other processing steps. The role of anti-tack adhesives is to provide stable and controllable bond strength, preventing component displacement or physical damage. After processing, rapid, residue-free, and damage-free complete peeling is required to improve chip processing yield and production efficiency. UV-curable peelable anti-tack adhesives, due to their mild triggering conditions and fast response speed, have become a research focus in the field of temporary fixation of precision components, and their performance affects the quality and cost of precision electronics manufacturing. Polyurethane's molecular structure offers excellent tunability; combining it with acrylates to construct a composite matrix combines the advantages of both. The urethane structure of the polyurethane hard segment can form a physical cross-linking network, giving the adhesive excellent adhesion, abrasion resistance, and mechanical strength. The acrylate soft segment can introduce abundant photoresponsive double bonds, providing active sites for efficient photocuring and photo-induced anti-tack. Therefore, developing a UV-induced peelable adhesive that combines high initial tack with photo-triggered high-efficiency tack reduction properties through chemical modification is of great practical significance for the semiconductor wafer processing field. Summary of the Invention

[0003] The purpose of this invention is to provide a polyurethane-based ultraviolet photosensitive peelable adhesive, which solves the problem that existing adhesives cannot meet the requirements for temporary fixation and efficient removal in semiconductor wafer processing.

[0004] Another object of the present invention is to provide a method for preparing a polyurethane-based ultraviolet photosensitive peelable adhesive.

[0005] The first technical solution adopted in this invention is: a polyurethane-based ultraviolet photosensitive peelable adhesive, which is composed of the following components by mass: 10 parts base adhesive, 0.05-0.4 parts curing agent, 0.5-2.5 parts photoinitiator, and 6 parts diluent; wherein the base adhesive is a polyurethane acrylate prepolymer.

[0006] The first technical solution of this invention is further characterized by:

[0007] The polyurethane acrylate prepolymer is composed of the following components by mass parts: 10-50 parts isocyanate intermediate, 100 parts polyacrylic acid resin, and 100 parts solvent.

[0008] The isocyanate intermediate is composed of the following components by mass: 37.6 parts isocyanate, 100 parts acrylate monomer, 120-150 parts solvent, and 0.25 parts catalyst.

[0009] The isocyanate is isophorone diisocyanate, the acrylate monomer is hydroxyethyl acrylate, and the catalyst is dibutyltin dilaurate.

[0010] The solvent is one or a combination of two or more of toluene, ethyl acetate, and butanone.

[0011] The curing agent is hexamethylene diisocyanate polyisocyanate, and the diluent is ethyl acetate.

[0012] The photoinitiator is one or a combination of two of 1-hydroxycyclohexylphenyl ketone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0013] The second technical solution adopted in this invention is: a method for preparing a polyurethane-based ultraviolet photosensitive peelable adhesive, comprising the following steps: Step 1: Weigh each component according to the mass fractions; Step 2: Add the isocyanate, acrylate monomer, part of the solvent and catalyst weighed in Step 1 into a container to react and generate the isocyanate intermediate; Step 3: Add the intermediate generated in Step 2, the polyacrylic acid resin weighed in Step 1, and the remaining solvent into a container to react and generate a polyurethane acrylate prepolymer. Step 4: Weigh the curing agent, photoinitiator, and diluent from Step 1 and add them to the prepolymer generated in Step 3. Stir until homogeneous to obtain the anti-tack adhesive liquid. Step 5: Apply the anti-tack adhesive solution obtained in Step 4 onto the PET film, dry it, cover it with a release film, and cure it to obtain the final product.

[0014] The beneficial effects of this invention are as follows: The polyurethane-based UV-curable peelable adhesive and its preparation method modify isocyanate intermediates and polyacrylic acid resin through chemical grafting to obtain a polyurethane acrylate prepolymer as the base adhesive. Compared with the traditional physical blending method, this effectively solves the problems of poor component compatibility and insufficient crosslinking, so that the adhesive layer has both the excellent mechanical properties of polyurethane and the efficient photocuring properties of acrylate, avoiding the problem of component damage caused by insufficient adhesive layer bonding performance during wafer processing. By optimizing the optimal addition ratio of each component, the prepared peelable tape has a high initial peel strength, which can provide a stable temporary fixation effect for wafer processing. After UV irradiation, the peel strength is significantly reduced, achieving rapid de-adhesion, and there is no adhesive residue after peeling, meeting the core requirements of temporary fixation and efficient, non-destructive removal in semiconductor wafer processing. Attached Figure Description

[0015] Figure 1This is an infrared spectrum characterization diagram of the polyurethane acrylate prepolymer obtained by the present invention. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0017] This invention provides a polyurethane-based UV-curable peelable adhesive, which is prepared by adding a curing agent, a photoinitiator and a diluent to a polyurethane acrylate prepolymer as the base adhesive. The components are in the following weight ratios: 10 parts polyurethane acrylate prepolymer, 0.05-0.4 parts curing agent, 0.5-2.5 parts photoinitiator and 6 parts diluent.

[0018] The polyurethane acrylate prepolymer is prepared by chemical modification of isocyanate intermediate and polyacrylic acid resin. The raw materials are proportioned by weight as follows: 10-50 parts (preferably 50 parts) of isocyanate intermediate, 100 parts of polyacrylic acid resin, and 100 parts of solvent. The isocyanate intermediate is synthesized from isocyanate and hydroxyethyl acrylate, with the following specific weight proportions: 37.6 parts of isocyanate, 100 parts of acrylate monomer (HEA), 120-150 parts (preferably 137.6 parts) of solvent, and 0.25 parts of catalyst.

[0019] The raw material composition includes acrylate monomer HEA (hydroxyethyl acrylate), isocyanate (isophorone diisocyanate (IPDI)), polyacrylic acid resin (AD1240), catalyst (DBTDL: dibutyltin dilaurate at a volume concentration of 1%), solvent (toluene (TOL), ethyl acetate, butanone), curing agent (XP2655: hexamethylene diisocyanate (HDI) polyisocyanate), photoinitiator (184: 1-hydroxy-cyclohexyl-phenyl ketone, TPO: 2,4,6-trimethylbenzoyl diphenylphosphine oxide), and diluent (ethyl acetate).

[0020] This invention provides a method for preparing a polyurethane-based ultraviolet photosensitive peelable adhesive, specifically implemented according to the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0021] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0022] like Figure 1 As shown, the prepolymer is in the range of 2240-2270 cm⁻¹ -1 The absence of the characteristic -NCO peak indicates that the isocyanate in the system has completely reacted, leaving no -NCO residue. (3375 cm⁻¹) -1 The peaks at the left and right correspond to the characteristic peaks of NH stretching, which are consistent with the characteristics of carbamates, and are related to the 1536 cm⁻¹ peak. -1 The characteristic peak of the amide at 1635 cm⁻¹ confirms that the isocyanate reacts with the hydroxyl group in the system to form a carbamate bond. -1 and 810 cm -1 The peak at this location is a characteristic peak of the C=C double bond in acrylate, indicating that the double bond is retained and can be used for subsequent UV curing. Infrared results show that this method successfully synthesized polyurethane acrylate prepolymers.

[0023] Step 3: Prepare UV-cured peelable adhesive solution: Weigh out 10 parts of the polyurethane acrylate prepolymer obtained in step 2, 0.05~0.4 parts of curing agent, 0.5~2.5 parts of photoinitiator, and 6 parts of diluent according to the weight ratio, and stir evenly at room temperature of 25°C to obtain UV-removable adhesive liquid.

[0024] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 is coated onto a PET film and dried in a constant temperature oven at 120°C for 45 seconds. After that, a release film is applied and the film is cured in a constant temperature oven at 45°C for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape.

[0025] In this invention, the acrylate monomer used is hydroxyethyl acrylate. Using this monomer and isocyanate as raw materials, an isocyanate intermediate is prepared under the action of a catalyst. This intermediate is then used to chemically modify polyacrylic acid resin to prepare a polyurethane acrylate prepolymer. A curing agent, photoinitiator, and diluent are added to the prepolymer. After coating, drying, and curing, a UV-removable adhesive with high adhesion and high tack-reducing properties is obtained.

[0026] The anti-tack adhesive prepared by this invention utilizes the synergistic effect of the urethane structure of the hard segment of polyurethane and the photoresponsive double bond of the soft segment of acrylate in the polyurethane acrylate prepolymer. This allows for precise control over the initial tack and photo-induced anti-tack properties of the tape, resulting in stable molecular bonding and a uniform cross-linking structure. The added curing agent regulates the initial cross-linking density of the adhesive layer, ensuring high adhesion during processing. The photoinitiator efficiently triggers the double bond cross-linking reaction under ultraviolet light, achieving rapid de-tack. This enables the preparation of a UV-peelable anti-tack adhesive for semiconductor wafer processing with high initial peel strength, rapid UV-induced anti-tack, and residue-free peeling. It is expected to provide a new temporary fixing adhesive material for the precision processing of semiconductor wafers. Furthermore, the preparation method of this invention features controllable process parameters, simple operation, and mild reaction conditions, facilitating industrial mass production. The resulting anti-tack tape exhibits stable performance and can be widely used in the processing and manufacturing of precision components such as chips and wafers.

[0027] Example 1 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0028] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0029] Step 3: Prepare UV-cured peelable adhesive solution: Weigh out 10 parts by weight of the polyurethane acrylate prepolymer obtained in step 2, 0.05 parts by weight of the curing agent, 0.5 parts by weight of the photoinitiator, and 6 parts by weight of the diluent. Stir the mixture evenly at room temperature of 25°C to obtain a UV-removable adhesive liquid.

[0030] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0031] Example 2 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0032] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0033] Step 3: Prepare UV-cured peelable adhesive solution: Weigh 10 parts of the polyurethane acrylate prepolymer obtained in step 2, 0.05 parts of the curing agent, 1 part of the photoinitiator, and 6 parts of the diluent according to the weight ratio, and stir evenly at room temperature of 25°C to obtain the UV-removable adhesive liquid.

[0034] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0035] Example 3 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0036] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0037] Step 3: Prepare UV-cured peelable adhesive solution: Weigh out 10 parts by weight of the polyurethane acrylate prepolymer obtained in step 2, 0.05 parts by weight of the curing agent, 1.5 parts by weight of the photoinitiator, and 6 parts by weight of the diluent. Stir the mixture evenly at room temperature of 25°C to obtain a UV-removable adhesive liquid.

[0038] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0039] Example 4 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0040] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0041] Step 3: Prepare UV-cured peelable adhesive solution: Weigh 10 parts of the polyurethane acrylate prepolymer obtained in step 2, 0.05 parts of the curing agent, 2 parts of the photoinitiator, and 6 parts of the diluent according to the weight ratio, and stir evenly at room temperature of 25°C to obtain the UV-removable adhesive liquid.

[0042] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0043] Example 5 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0044] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0045] Step 3: Prepare UV-cured peelable adhesive solution: Weigh out 10 parts by weight of the polyurethane acrylate prepolymer obtained in step 2, 0.05 parts by weight of the curing agent, 2.5 parts by weight of the photoinitiator, and 6 parts by weight of the diluent. Stir the mixture evenly at room temperature of 25°C to obtain a UV-removable adhesive liquid.

[0046] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0047] Example 6 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0048] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0049] Step 3: Prepare UV-cured peelable adhesive solution: Weigh 10 parts by weight of the polyurethane acrylate prepolymer obtained in step 2, 0.1 parts by weight of the curing agent, 2 parts by weight of the photoinitiator, and 6 parts by weight of the diluent. Stir the mixture evenly at room temperature of 25°C to obtain a UV-removable adhesive liquid.

[0050] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0051] Example 7 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0052] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0053] Step 3: Prepare UV-cured peelable adhesive solution: Weigh 10 parts of the polyurethane acrylate prepolymer obtained in step 2, 0.2 parts of the curing agent, 2 parts of the photoinitiator, and 6 parts of the diluent according to the weight ratio, and stir evenly at room temperature of 25°C to obtain the UV-removable adhesive liquid.

[0054] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0055] Example 8 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0056] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0057] Step 3: Prepare UV-cured peelable adhesive solution: Weigh out 10 parts by weight of the polyurethane acrylate prepolymer obtained in step 2, 0.3 parts by weight of the curing agent, 2 parts by weight of the photoinitiator, and 6 parts by weight of the diluent. Stir the mixture evenly at room temperature of 25°C to obtain a UV-removable adhesive liquid.

[0058] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0059] Example 9 A method for preparing a polyurethane-based UV-repellent peelable adhesive includes the following steps: Step 1: Preparation of isocyanate intermediates: Weigh out 100 parts by weight of hydroxyethyl acrylate, 37.6 parts by weight of isophorone diisocyanate (IPDI), and 137.6 parts by weight of toluene and add them to a four-necked flask. Heat and stir, add 0.25 parts by weight of catalyst, and react at 80°C for 24 hours to generate an isocyanate intermediate.

[0060] Step 2: Preparation of polyurethane acrylate prepolymer: Weigh 50 parts by weight of the intermediate obtained in step 1, 100 parts by weight of polyacrylic acid resin and 100 parts by weight of toluene and add them to a four-necked flask. React at 60°C for 12 hours to generate polyurethane acrylate prepolymer.

[0061] Step 3: Prepare UV-cured peelable adhesive solution: Weigh 10 parts of the polyurethane acrylate prepolymer obtained in step 2, 0.4 parts of the curing agent, 2 parts of the photoinitiator, and 6 parts of the diluent according to the weight ratio, and stir evenly at room temperature of 25°C to obtain the UV-removable adhesive liquid.

[0062] Step 4: Prepare UV-cured peelable adhesive tape: The anti-tack adhesive obtained in step 3 was coated onto a PET film with a coating thickness of (10±1) μm. The film was dried in a 120℃ oven for 45 seconds, then covered with a release film and cured in a 45℃ oven for 12 hours to obtain a polyurethane-based UV-releasable anti-tack tape. Following GB / T 2792-2014, the above sample was irradiated with ultraviolet light, and the 180° peel strength of the sample before and after irradiation was tested.

[0063] Table 1. Results of UV-induced peel strength test for peelable adhesives.

[0064] As can be seen from Table 1 above, by optimizing the optimal addition ratio of each component, the initial peel strength of the prepared anti-adhesion tape can reach as high as 1665gf / 25mm, which can provide a stable temporary fixing effect for wafer processing. After UV irradiation, the peel strength can be significantly reduced to 1.2gf / 25mm, achieving rapid de-adhesion, and there is no residue after peeling.

Claims

1. A polyurethane-based UV-cured peelable adhesive, characterized in that, The product is composed of the following components by weight: 10 parts base adhesive, 0.05-0.4 parts curing agent, 0.5-2.5 parts photoinitiator, and 6 parts diluent; wherein the base adhesive is a polyurethane acrylate prepolymer.

2. The polyurethane-based UV-cured peelable adhesive as described in claim 1, characterized in that, The polyurethane acrylate prepolymer is composed of the following components in parts by mass: 10-50 parts isocyanate intermediate, 100 parts polyacrylic acid resin, and 100 parts solvent.

3. The polyurethane-based UV-cured peelable adhesive as described in claim 2, characterized in that, The isocyanate intermediate is composed of the following components in parts by mass: 37.6 parts isocyanate, 100 parts acrylate monomer, 120-150 parts solvent, and 0.25 parts catalyst.

4. The polyurethane-based UV-cured peelable adhesive as described in claim 3, characterized in that, The isocyanate is isophorone diisocyanate, the acrylate monomer is hydroxyethyl acrylate, and the catalyst is dibutyltin dilaurate.

5. The polyurethane-based UV-cured peelable adhesive as described in claim 3, characterized in that, The solvent is one or a combination of two or more of toluene, ethyl acetate, and butanone.

6. The polyurethane-based UV-cured peelable adhesive as described in claim 1, characterized in that, The curing agent is hexamethylene diisocyanate polyisocyanate, and the diluent is ethyl acetate.

7. The polyurethane-based UV-cured peelable adhesive as described in claim 1, characterized in that, The photoinitiator is one or a combination of two of 1-hydroxycyclohexylphenyl ketone and 2,4,6-trimethylbenzoyl diphenylphosphine oxide.

8. The method for preparing the polyurethane-based ultraviolet photosensitive peelable adhesive as described in claim 3, characterized in that, Includes the following steps: Step 1: Weigh each component according to the mass fractions; Step 2: Add the isocyanate, acrylate monomer, part of the solvent and catalyst weighed in Step 1 into a container to react and generate the isocyanate intermediate; Step 3: Add the intermediate generated in Step 2, the polyacrylic acid resin weighed in Step 1, and the remaining solvent into a container to react and generate a polyurethane acrylate prepolymer. Step 4: Weigh the curing agent, photoinitiator, and diluent from Step 1 and add them to the prepolymer generated in Step 3. Stir until homogeneous to obtain the anti-tack adhesive liquid. Step 5: Apply the anti-tack adhesive solution obtained in Step 4 onto the PET film, dry it, cover it with a release film, and cure it to obtain the final product.

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