A high loop initial adhesion, high holding adhesion removable type BOPP pressure sensitive adhesive tape and a preparation method thereof

Abstract

This invention discloses a high-initial-tack, high-holding-force, removable BOPP pressure-sensitive adhesive tape and its preparation method, belonging to the field of pressure-sensitive adhesive technology. The tape comprises, from top to bottom, a release layer, a pressure-sensitive adhesive layer, and a BOPP base film layer. The pressure-sensitive adhesive layer is cured from a solvent-modified acrylate pressure-sensitive adhesive, and its raw materials include a specific ratio of soft monomers, hard monomers, functional polar monomers, initiators, and solvents. Preparation involves BOPP base film corona pretreatment, solution free radical polymerization, segmented coating drying, and constant-temperature curing. Tests show that this invention successfully solves the technical problem of traditional pressure-sensitive adhesives' difficulty in simultaneously achieving high initial tack and holding power, and the inability to remove due to strong adhesion, through the synergistic effect of glycerol esterified rosin and polyether-modified silicone. The resulting tape has an initial tack of 10.85-11.26 N / 25 mm, a holding power >72 h (2 kg), and leaves no residue after peeling after aging at 70℃ for 3 days. It is suitable for temporary fixing of electronic products, label positioning, and surface protection.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive technology, specifically to a high-initial-tack, high-holding-force, repositionable BOPP pressure-sensitive tape and its preparation method. Background Technology

[0002] BOPP pressure-sensitive adhesive tape is currently the most widely used adhesive material in packaging, electronics, printing, and household goods industries. Ordinary BOPP tapes mostly use common acrylic pressure-sensitive adhesives, which generally exhibit significant performance inconsistencies:

[0003] 1) The initial tack is too low, resulting in slow adhesion and easy lifting or poor adhesion. 2) Simply increasing the initial tack results in insufficient cohesion of the adhesive layer and poor holding power, making it easy to slip off or detach after prolonged hanging. 3) High-tack tapes are prone to leaving residue, pulling, and tearing of the bonded surface when peeled off, making it impossible to achieve repositioning and repeated bonding. Most existing repositionable tapes have weak initial tack and poor holding power, and can only provide slight fixation, failing to meet the needs of high-strength temporary bonding.

[0004] Currently, it is difficult in the industry to simultaneously achieve high initial tack, high long-lasting tack, and clean, removable residue-free adhesion. Either it adheres well but cannot be removed, leaving residue; or it can be removed cleanly but does not adhere firmly and is easy to fall off.

[0005] Therefore, developing a BOPP tape that can adhere instantly, stay in place for a long time, be easily moved, and peel off without leaving a trace has significant practical application value. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] Therefore, the purpose of this invention is to provide a high-initial-tack, high-holding-force, movable BOPP pressure-sensitive tape and its preparation method, so as to solve the problems mentioned in the background art.

[0008] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0009] A movable BOPP pressure-sensitive tape with high initial tack and high holding power, comprising, from top to bottom, a release layer, a pressure-sensitive adhesive layer, and a BOPP base film layer;

[0010] The pressure-sensitive adhesive layer is cured from a solvent-modified acrylic pressure-sensitive adhesive, which, by weight, comprises the following raw material components:

[0011] The composition includes 70-83 parts of soft monomer, 6-10 parts of hard monomer, 2.5-5 parts of functional polar monomer, 5-10 parts of cohesive modified resin, 0.1-1 parts of toughening and softening agent, 0.2-1.2 parts of composite crosslinking agent, 0.3-0.6 parts of initiator, and solvent;

[0012] The cohesive-modifying resin is glycerol esterified polymerized rosin, and the toughening and softening agent is polyether-modified organosilicon.

[0013] As a preferred embodiment of the high initial tack and high holding power removable BOPP pressure-sensitive tape of the present invention, the thickness of the BOPP base film layer is 25-50μm and the surface tension is ≥38mN / m; the dry film thickness of the pressure-sensitive adhesive layer is 15-28μm; and the release layer is a single-sided silicone-coated PET release film or glassine release paper.

[0014] As a preferred embodiment of the high initial tack and high holding power movable BOPP pressure-sensitive tape of the present invention, the soft monomer is selected from one or more of isooctyl acrylate, n-butyl acrylate, and ethyl acrylate.

[0015] The hard monomer is selected from one or more of methyl methacrylate and vinyl acetate;

[0016] The functional polar monomer is selected from one or more of acrylic acid and hydroxyethyl acrylate.

[0017] As a preferred embodiment of the high initial tack and high holding power removable BOPP pressure-sensitive tape of the present invention, the composite crosslinking agent is selected from one or more of isocyanate crosslinking agents, epoxy crosslinking agents, and metal complex crosslinking agents, the initiator is azobisisobutyronitrile, and the solvent is a mixture of ethyl acetate and toluene.

[0018] A method for preparing a removable BOPP pressure-sensitive tape with high initial tack and high holding power includes the following steps:

[0019] S1. Corona treatment is applied to one side of the BOPP base film;

[0020] S2. Mix the soft monomer, hard monomer, functional polar monomer and a portion of the solvent, add an initiator to carry out a free radical polymerization reaction, then add glycerol esterified polymerized rosin, polyether modified organosilicon and composite crosslinking agent, stir and mix and filter to obtain pressure-sensitive adhesive liquid.

[0021] S3. Apply the pressure-sensitive adhesive liquid to the surface of the treated BOPP base film, bake in stages to remove solvent and pre-crosslink to obtain BOPP pressure-sensitive adhesive.

[0022] S4. Lay a release layer onto the BOPP pressure-sensitive adhesive surface, then cure at a constant temperature, and finally slit and roll up to obtain the finished product.

[0023] In a preferred embodiment of the preparation method of the high-ring initial tack and high-holding-force movable BOPP pressure-sensitive tape of the present invention, the power of the corona treatment in step S1 is 120-160W.

[0024] As a preferred embodiment of the preparation method of the high ring initial tack and high holding power movable BOPP pressure-sensitive tape of the present invention, in step S2, the temperature of the free radical polymerization reaction is 75-85℃ and the heat preservation reaction time is 6-8h.

[0025] The low-speed stirring time after adding glycerol esterified polymerized rosin, polyether modified organosilicon and composite crosslinking agent is 30-45 min.

[0026] As a preferred embodiment of the preparation method of the high ring initial tack and high holding power movable BOPP pressure-sensitive tape of the present invention, in step S3, the coating method is comma doctor blade coating and the coating speed is 80-120m / min.

[0027] The temperature gradients for the segmented baking are 70℃, 85℃, 95℃ and 80℃ respectively.

[0028] As a preferred embodiment of the preparation method of the high-ring initial tack and high-holding-force movable BOPP pressure-sensitive tape of the present invention, in step S4, the temperature of the constant temperature curing is 45-50℃ and the curing time is 24-36h.

[0029] Application of a high-ring initial tack and high-holding-force removable BOPP pressure-sensitive tape in the fields of temporary fixation of electronic products, label positioning, board bonding, temporary bundling or surface protection.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. This invention introduces glycerol esterified polymerized rosin, which significantly improves the initial bond strength of the adhesive while enhancing peel strength and maintaining good tack. Traditional tackifying resins, being small molecules present in the colloid, do improve peel strength to some extent, but simultaneously reduce the initial bond strength and holding power of the adhesive, failing to balance the mechanical properties of the adhesive. Glycerol esterified polymerized rosin overcomes these shortcomings of traditional rosin.

[0032] 2. This invention improves the leveling properties of the adhesive layer, reduces pinholes, and enhances the uniformity and bonding reliability of the adhesive layer by introducing polyether-modified silicone. Its core function is to significantly reduce surface tension through a "hydrophilic-hydrophobic" hybrid structure, thereby enhancing wetting and adhesion to difficult-to-wet substrates. This allows the adhesive layer to bond tightly with BOPP, improving portability and solving the problems of difficult wetting of BOPP substrates and easy adhesive layer delamination. Detailed Implementation

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0034] Example 1

[0035] S1. BOPP Base Film Pretreatment: Select a 50μm thick ordinary glossy BOPP film and perform corona activation treatment on one side using a corona treatment machine, setting the corona power to 140W. After treatment, the surface tension is tested with a dyne pen and found to be 40mN / m, meeting the adhesion requirements. The film is then wound up for later use.

[0036] S2. Preparation of modified acrylate pressure-sensitive adhesive by polymerization: In a 3L four-necked flask equipped with a condenser, stirrer, thermometer, and dropping funnel, add 52 parts of isooctyl acrylate, 25 parts of n-butyl acrylate, 8 parts of methyl methacrylate, 2 parts of acrylic acid, 1.4 parts of hydroxyethyl acrylate, and a mixed solvent of ethyl acetate and toluene (ethyl acetate to toluene mass ratio of 7:3) accounting for 60% of the total solvent mass. Start stirring and heat to 80℃;

[0037] After the temperature stabilizes, 0.4 parts of the initiator azobisisobutyronitrile (AIBN) are added dropwise in batches, controlling the dropping rate to maintain the reaction temperature between 75-85℃. After the addition is complete, the reaction is maintained at this temperature for 7 hours to carry out free radical polymerization.

[0038] After the reaction was completed, the material in the reactor was cooled to 50°C. Then, 10 parts of glycerol-esterified polymerized rosin, 1 part of polyether-modified organosilicon (BYK-310), and 0.6 parts of a metal complex crosslinking agent (such as a titanium complex) were added. The remaining 40% of the mixed solvent was added to adjust the solid content of the system to 50%. Stirring was started and controlled at 300 rpm for 40 minutes to ensure uniform mixing of all components. Finally, the mixture was filtered through a 200-mesh filter cloth, and the product was discharged to obtain a pale yellow, transparent, removable, high-ring-strength, high-holding-weight pressure-sensitive adhesive liquid.

[0039] S3. Coating and Drying: Using a comma-shaped doctor blade coater, the pressure-sensitive adhesive liquid prepared above is evenly coated onto the corona surface of the pretreated BOPP base film. The wet coating thickness is controlled so that the dry adhesive layer thickness reaches 25μm after drying.

[0040] The coated wet film enters a four-stage drying oven for segmented drying and pre-crosslinking. The temperatures of each stage are set sequentially as follows: stage 1 70℃, stage 2 85℃, stage 3 95℃, and stage 4 80℃. The coating speed is 100 m / min. This temperature profile facilitates the gradual removal of solvent and the stretching and pre-crosslinking of molecular chains.

[0041] S4. Laying release material: On the composite surface of the pressure-sensitive adhesive layer, a single-sided silicone-coated PET release film with a thickness of 25μm is laminated, pressed by a composite roller, and then wound up to obtain a composite semi-finished roll material.

[0042] S5. Constant Temperature Curing and Slitting: The composite semi-finished roll material is transferred to a constant temperature curing chamber, with the curing temperature set at 50℃ and the curing time at 30 hours. This promotes complete cross-linking reaction within the adhesive layer and stabilizes the cohesive force. After curing, the roll material is slitted into finished rolls of specified widths using a slitting machine according to customer requirements. The rolls are then rewound and packaged to obtain a high-yield initial tack, high-holding-force, repositionable BOPP pressure-sensitive tape.

[0043] Example 2

[0044] S1. BOPP Base Film Pretreatment: Select a 38μm thick ordinary glossy BOPP film and perform corona activation treatment on one side using a corona treatment machine, setting the corona power to 120W. After treatment, the surface tension is tested with a dyne pen and found to be 39mN / m, meeting the adhesion requirements. The film is then wound up for later use.

[0045] S2. Preparation of modified acrylate pressure-sensitive adhesive by polymerization: In a 3L four-necked flask equipped with a condenser, stirrer, thermometer, and dropping funnel, add 48 parts of isooctyl acrylate, 28 parts of n-butyl acrylate, 6 parts of methyl methacrylate, 1.5 parts of acrylic acid, 1 part of hydroxyethyl acrylate, and a mixed solvent of ethyl acetate and toluene (ethyl acetate to toluene mass ratio of 7:3) accounting for 60% of the total solvent mass. Start stirring and heat to 78℃.

[0046] After the temperature stabilizes, 0.5 parts of the initiator azobisisobutyronitrile (AIBN) are added dropwise in batches, controlling the dropping rate to maintain the reaction temperature between 75-85℃. After the addition is complete, the reaction is maintained at this temperature for 8 hours to carry out free radical polymerization.

[0047] After the reaction was completed, the material in the reactor was cooled to 45°C. Then, 8 parts of glycerol-esterified polymerized rosin, 0.6 parts of polyether-modified silicone (BYK-310), and 1 part of isocyanate crosslinking agent (such as TDI trimer) were added. The remaining 40% of the mixed solvent was added to adjust the solid content of the system to 50%. Stirring was started and controlled at 350 rpm for 35 minutes to ensure uniform mixing of all components. Finally, the mixture was filtered through a 200-mesh filter cloth and discharged to obtain a pale yellow, transparent, removable, high-ring-strength, high-holding-weight pressure-sensitive adhesive liquid.

[0048] S3. Coating and Drying: Using a comma-shaped doctor blade coater, the pressure-sensitive adhesive liquid prepared above is evenly coated onto the corona surface of the pretreated BOPP base film. The wet coating thickness is controlled so that the dry adhesive layer thickness reaches 25μm after drying.

[0049] The coated wet film enters a four-stage drying oven for segmented drying and pre-crosslinking. The temperatures of each stage are set sequentially as follows: stage 1 70℃, stage 2 85℃, stage 3 95℃, and stage 4 80℃. The coating speed is 90 m / min. This temperature profile facilitates the gradual removal of solvent and the stretching and pre-crosslinking of molecular chains.

[0050] S4. Laying release material: On the composite surface of the pressure-sensitive adhesive layer, a single-sided silicone-coated PET release film with a thickness of 25μm is laminated, pressed by a composite roller, and then wound up to obtain a composite semi-finished roll material.

[0051] S5. Constant Temperature Curing and Slitting: The composite semi-finished roll material is transferred to a constant temperature curing chamber, with the curing temperature set at 50℃ and the curing time at 30 hours. This promotes complete cross-linking reaction within the adhesive layer and stabilizes the cohesive force. After curing, the roll material is slitted into finished rolls of specified widths using a slitting machine according to customer requirements. The rolls are then rewound and packaged to obtain a high-yield initial tack, high-holding-force, repositionable BOPP pressure-sensitive tape.

[0052] Example 3

[0053] S1. BOPP Base Film Pretreatment: Select a 50μm thick ordinary glossy BOPP film and perform corona activation treatment on one side using a corona treatment machine, setting the corona power to 150W. After treatment, the surface tension is tested with a dyne pen and found to be 41mN / m, meeting the adhesion requirements. The film is then wound up for later use.

[0054] S2. Preparation of modified acrylate pressure-sensitive adhesive by polymerization: In a 3L four-necked flask equipped with a condenser, stirrer, thermometer, and dropping funnel, add 55 parts of isooctyl acrylate, 22 parts of n-butyl acrylate, 10 parts of methyl methacrylate, 3 parts of acrylic acid, 2 parts of hydroxyethyl acrylate, and a mixed solvent of ethyl acetate and toluene (ethyl acetate to toluene mass ratio of 7:3) accounting for 60% of the total solvent mass. Start stirring and heat to 82℃.

[0055] After the temperature stabilizes, 0.5 parts of the initiator azobisisobutyronitrile (AIBN) are added dropwise in batches, controlling the dropping rate to maintain the reaction temperature between 75-85℃. After the addition is complete, the reaction is maintained at this temperature for 6.5 hours to carry out free radical polymerization.

[0056] After the reaction was completed, the material in the reactor was cooled to 50°C. Then, 9 parts of glycerol-esterified polymerized rosin, 0.8 parts of polyether-modified silicone (BYK-310), and 0.8 parts of epoxy crosslinking agent (such as triglycidyl isocyanate) were added. The remaining 40% of the mixed solvent was added to adjust the solid content of the system to 50%. Stirring was started and controlled at 320 rpm for 30 minutes to ensure uniform mixing of all components. Finally, the mixture was filtered through a 200-mesh filter cloth and discharged to obtain a pale yellow, transparent, removable, high-ring-strength, high-holding-weight pressure-sensitive adhesive liquid.

[0057] S3. Coating and Drying: Using a comma-shaped doctor blade coater, the pressure-sensitive adhesive liquid prepared above is evenly coated onto the corona surface of the pretreated BOPP base film. The wet coating thickness is controlled so that the dry adhesive layer thickness reaches 25μm after drying.

[0058] The coated wet film enters a four-stage drying oven for segmented drying and pre-crosslinking. The temperatures of each stage are set sequentially as follows: stage 1 70℃, stage 2 85℃, stage 3 95℃, and stage 4 80℃. The coating speed is 110 m / min. This temperature profile facilitates the gradual removal of solvent and the stretching and pre-crosslinking of molecular chains.

[0059] S4. Laying release material: On the composite surface of the pressure-sensitive adhesive layer, a single-sided silicone-coated PET release film with a thickness of 25μm is laminated, pressed by a composite roller, and then wound up to obtain a composite semi-finished roll material.

[0060] S5. Constant Temperature Curing and Slitting: The composite semi-finished roll material is transferred to a constant temperature curing chamber, with the curing temperature set at 45℃ and the curing time at 36 hours. This promotes complete cross-linking reaction within the adhesive layer and stabilizes the cohesive force. After curing, the roll material is slitted into finished rolls of specified widths using a slitting machine according to customer requirements. The rolls are then rewound and packaged to obtain a high-yield initial tack, high-holding-force, repositionable BOPP pressure-sensitive tape.

[0061] Example 4

[0062] S1. BOPP Base Film Pretreatment: Select a 25μm thick ordinary glossy BOPP film and perform corona activation treatment on one side using a corona treatment machine, setting the corona power to 160W. After treatment, the surface tension is tested with a dyne pen and found to be 40mN / m, meeting the adhesion requirements. The film is then wound up for later use.

[0063] S2. Preparation of modified acrylate pressure-sensitive adhesive by polymerization: In a 3L four-necked flask equipped with a condenser, stirrer, thermometer, and dropping funnel, add 50 parts of isooctyl acrylate, 24 parts of n-butyl acrylate, 6 parts of ethyl acrylate, 6 parts of methyl methacrylate, 2 parts of vinyl acetate, 1.5 parts of acrylic acid, 1 part of hydroxyethyl acrylate, and a mixed solvent of ethyl acetate and toluene (ethyl acetate to toluene mass ratio of 7:3) accounting for 60% of the total solvent mass. Start stirring and heat to 85℃.

[0064] After the temperature stabilizes, 0.6 parts of the initiator azobisisobutyronitrile (AIBN) are added dropwise in batches, controlling the dropping rate to maintain the reaction temperature between 75-85℃. After the addition is complete, the reaction is maintained at this temperature for 6 hours to carry out free radical polymerization.

[0065] After the reaction was completed, the material in the reactor was cooled to 50°C. Then, 8.8 parts of glycerol-esterified polymerized rosin, 0.6 parts of polyether-modified silicone (BYK-310), and 1.2 parts of isocyanate crosslinking agent (such as TDI trimer) were added. The remaining 40% of the mixed solvent was added to adjust the solid content of the system to 50%. Stirring was started and controlled at 300 rpm for 45 minutes to ensure uniform mixing of all components. Finally, the mixture was filtered through a 200-mesh filter cloth and discharged to obtain a pale yellow, transparent, removable, high-ring-strength, high-holding-weight pressure-sensitive adhesive liquid.

[0066] S3. Coating and Drying: Using a comma-shaped doctor blade coater, the pressure-sensitive adhesive liquid prepared above is evenly coated onto the corona surface of the pretreated BOPP base film. The wet coating thickness is controlled so that the dry adhesive layer thickness reaches 15μm after drying.

[0067] The coated wet film enters a four-stage drying oven for segmented drying and pre-crosslinking. The temperatures of each stage are set sequentially as follows: stage 1 70℃, stage 2 85℃, stage 3 95℃, and stage 4 80℃. The coating speed is 120 m / min. This temperature profile facilitates the gradual removal of solvent and the stretching and pre-crosslinking of molecular chains.

[0068] S4. Laying release material: On the composite surface of the pressure-sensitive adhesive layer, apply qualified Racine release paper, press with a composite roller, and then roll up to obtain a composite semi-finished roll material.

[0069] S5. Constant Temperature Curing and Slitting: The composite semi-finished roll material is transferred into a constant temperature curing chamber, with the curing temperature set at 48℃ and the curing time at 28 hours. This promotes complete cross-linking reaction within the adhesive layer and stabilizes the cohesive force. After curing, the roll material is slitted into finished rolls of specified widths using a slitting machine according to customer requirements. The rolls are then rewound and packaged to obtain a high-yield initial tack, high-holding-force, repositionable BOPP pressure-sensitive tape.

[0070] Comparative Example 1

[0071] S1. BOPP Base Film Pretreatment: Select a 50μm thick ordinary glossy BOPP film and perform corona activation treatment on one side using a corona treatment machine, setting the corona power to 140W. After treatment, the surface tension is tested with a dyne pen and found to be 40mN / m, meeting the adhesion requirements. The film is then wound up for later use.

[0072] S2. Preparation of modified acrylate pressure-sensitive adhesive by polymerization: In a 3L four-necked flask equipped with a condenser, stirrer, thermometer, and dropping funnel, add 52 parts of isooctyl acrylate, 25 parts of n-butyl acrylate, 8 parts of methyl methacrylate, 2 parts of acrylic acid, 1.4 parts of hydroxyethyl acrylate, and a mixed solvent of ethyl acetate and toluene (ethyl acetate to toluene mass ratio of 7:3) accounting for 60% of the total solvent mass. Start stirring and heat to 80℃.

[0073] After the temperature stabilizes, 0.4 parts of the initiator azobisisobutyronitrile (AIBN) are added dropwise in batches, controlling the dropping rate to maintain the reaction temperature between 75-85℃. After the addition is complete, the reaction is maintained at this temperature for 7 hours to carry out free radical polymerization.

[0074] After the reaction was complete, the material in the reactor was cooled to 50°C. Then, 10 parts of terpene phenol resin, 1 part of polyether-modified organosilicon (BYK-310), and 0.6 parts of a metal complex crosslinking agent (such as a titanium complex) were added. The remaining 40% of the mixed solvent was added to adjust the solid content of the system to 50%. Stirring was started and controlled at 300 rpm for 40 minutes to ensure uniform mixing of all components. Finally, the mixture was filtered through a 200-mesh filter cloth and discharged to obtain a pressure-sensitive adhesive solution.

[0075] S3. Coating and Drying: Using a comma-shaped doctor blade coater, the pressure-sensitive adhesive liquid prepared above is evenly coated onto the corona surface of the pretreated BOPP base film. The wet coating thickness is controlled so that the dry adhesive layer thickness reaches 25μm after drying.

[0076] The coated wet film enters a four-section drying oven for segmented drying and pre-crosslinking. The temperature settings for each section are as follows: 70℃ for the first section, 85℃ for the second section, 95℃ for the third section, and 80℃ for the fourth section. The coating speed is 100m / min.

[0077] S4. Laying release material: On the composite surface of the pressure-sensitive adhesive layer, a single-sided silicone-coated PET release film with a thickness of 25μm is laminated, pressed by a composite roller, and then wound up to obtain a composite semi-finished roll material.

[0078] S5. Constant Temperature Curing and Slitting: The composite semi-finished roll material is transferred into a constant temperature curing chamber, and the curing temperature is set to 50℃ for 30 hours. After curing, the roll material is slitted into finished rolls of the specified width using a slitting machine, rewound, and packaged to obtain the sample of Comparative Example 1.

[0079] Comparative Example 2

[0080] S1. BOPP Base Film Pretreatment: Select a 38μm thick ordinary glossy BOPP film and perform corona activation treatment on one side using a corona treatment machine, setting the corona power to 120W. After treatment, the surface tension is tested with a dyne pen and found to be 39mN / m, meeting the adhesion requirements. The film is then wound up for later use.

[0081] S2. Preparation of modified acrylate pressure-sensitive adhesive by polymerization: In a 3L four-necked flask equipped with a condenser, stirrer, thermometer, and dropping funnel, add 48 parts of isooctyl acrylate, 28 parts of n-butyl acrylate, 6 parts of methyl methacrylate, 1.5 parts of acrylic acid, 1 part of hydroxyethyl acrylate, and a mixed solvent of ethyl acetate and toluene (ethyl acetate to toluene mass ratio of 7:3) accounting for 60% of the total solvent mass. Start stirring and heat to 78℃.

[0082] After the temperature stabilizes, 0.5 parts of the initiator azobisisobutyronitrile (AIBN) are added dropwise in batches, controlling the dropping rate to maintain the reaction temperature between 75-85℃. After the addition is complete, the reaction is maintained at this temperature for 8 hours to carry out free radical polymerization.

[0083] After the reaction is complete, the material in the reactor is cooled to 45°C. Eight parts of glycerol-esterified polymerized rosin and one part of isocyanate crosslinking agent (such as TDI trimer) are added. No polyether-modified silicone is added in this step. The remaining solvent is then added to adjust the solid content of the system to 50%. Stirring is started, and the speed is controlled at 350 rpm for 35 minutes. After thorough mixing, the mixture is filtered through a 200-mesh filter cloth and discharged to obtain the pressure-sensitive adhesive solution.

[0084] S3. Glue application and drying / curing:

[0085] Using a comma-shaped doctor blade coater, the pressure-sensitive adhesive liquid prepared above is evenly coated onto the corona surface of the pretreated BOPP base film, and the wet coating thickness is controlled so that the dry adhesive layer thickness reaches 25μm after drying.

[0086] The coated wet film enters a four-section drying oven for segmented drying and pre-crosslinking. The temperature settings for each section are as follows: 70℃ for the first section, 85℃ for the second section, 95℃ for the third section, and 80℃ for the fourth section. The coating speed is 90m / min.

[0087] S4. Laying release material: On the composite surface of the pressure-sensitive adhesive layer, a single-sided silicone-coated PET release film with a thickness of 25μm is laminated, pressed by a composite roller, and then wound up to obtain a composite semi-finished roll material.

[0088] S5. Constant Temperature Curing and Slitting: The composite semi-finished roll material is transferred into a constant temperature curing chamber, and the curing temperature is set to 50℃ for 30 hours. After curing, the roll material is slitted into finished rolls of the specified width using a slitting machine, rewound, and packaged to obtain Comparative Example 2 sample.

[0089] Performance testing:

[0090] The tape samples prepared in Examples 1-4 and Comparative Examples 1-2 were placed in the same standard environment (temperature 23±2℃, relative humidity 50±5%) for 24 hours before performance testing. The results are shown in Table 1.

[0091] Table 1 - Performance test results of the tape samples prepared in Examples 1-4 and Comparative Examples 1-2

[0092] Initial tack (N / 25mm) GB / T 2792 10.96 11.26 10.85 11.02 8.25 10.65 Peel strength of steel plate (N / 25mm) GB / T 2792 10.65 10.06 10.12 9.89 10.89 9.62 Holding force (RT*2Kg) GB / T 4851 >72h >72h >72h >72h 20h drop Drops in 23 hours Portability performance testing 70℃*3 days, steel plate attached No residue No residue No residue No residue 30% residual degumming 80% residual degumming

[0093] As shown in Table 1, comparing Example 1 and Comparative Example 1, it is evident that using glycerol-esterified polymerized rosin as the cohesive modifier significantly improves the initial tack and holding power of the pressure-sensitive adhesive (holding time increased from 20 hours to over 72 hours) compared to traditional terpene phenolic resins, and maintains excellent residue-free performance even after high-temperature aging. This demonstrates that glycerol-esterified polymerized rosin effectively improves the cohesive strength and initial bond strength of the adhesive while enhancing peel strength. Comparing Example 2 and Comparative Example 2, it is clear that the addition of polyether-modified silicone is crucial for improving the tape's portability. Without this component, the interfacial bonding between the adhesive layer and the BOPP substrate decreases, leading to severe residue and debonding under high-temperature and high-humidity conditions (residual debonding rate reaches 80%). This verifies that polyether-modified silicone enhances the wetting and adhesion of the adhesive layer to the low surface energy substrate (BOPP) by reducing surface tension, thereby achieving high-strength portability.

[0094] Data from Examples 1-4 show that by adjusting the ratio of soft and hard monomers, the type and amount of crosslinking agent, the present invention can achieve a unified performance of high initial ring adhesion (>10.8 N / 25mm), high holding adhesion (>72h), and traceless mobility, indicating that the technical solution of the present invention has a good process window and stability.

[0095] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A repositionable BOPP pressure-sensitive tape with high initial tack and high holding power, characterized in that, From top to bottom, it includes a release layer, a pressure-sensitive adhesive layer, and a BOPP base film layer; The pressure-sensitive adhesive layer is cured from a solvent-modified acrylic pressure-sensitive adhesive, which, by weight, comprises the following raw material components: The composition includes 70-83 parts of soft monomer, 6-10 parts of hard monomer, 2.5-5 parts of functional polar monomer, 5-10 parts of cohesive modified resin, 0.1-1 parts of toughening and softening agent, 0.2-1.2 parts of composite crosslinking agent, 0.3-0.6 parts of initiator, and solvent; The cohesive-modifying resin is glycerol esterified polymerized rosin, and the toughening and softening agent is polyether-modified organosilicon.

2. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 1, characterized in that, The BOPP base film layer has a thickness of 25-50μm and a surface tension of ≥38mN / m; the dry film thickness of the pressure-sensitive adhesive layer is 15-28μm; and the release layer is a single-sided silicone-coated PET release film or glassine release paper.

3. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 1, characterized in that, The soft monomer is selected from one or more of isooctyl acrylate, n-butyl acrylate, and ethyl acrylate; The hard monomer is selected from one or more of methyl methacrylate and vinyl acetate; The functional polar monomer is selected from one or more of acrylic acid and hydroxyethyl acrylate.

4. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 1, characterized in that, The composite crosslinking agent is selected from one or more of isocyanate crosslinking agents, epoxy crosslinking agents, and metal complex crosslinking agents, the initiator is azobisisobutyronitrile, and the solvent is a mixture of ethyl acetate and toluene.

5. A method for preparing a high-annular-initial-tack, high-holding-force, repositionable BOPP pressure-sensitive tape as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Corona treatment is applied to one side of the BOPP base film; S2. Mix the soft monomer, hard monomer, functional polar monomer and a portion of the solvent, add an initiator to carry out a free radical polymerization reaction, then add glycerol esterified polymerized rosin, polyether modified organosilicon and composite crosslinking agent, stir and mix and filter to obtain pressure-sensitive adhesive liquid. S3. Apply the pressure-sensitive adhesive liquid to the surface of the treated BOPP base film, bake in stages to remove solvent and pre-crosslink to obtain BOPP pressure-sensitive adhesive. S4. Lay a release layer onto the BOPP pressure-sensitive adhesive surface, then cure at a constant temperature, and finally slit and roll up to obtain the finished product.

6. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 5, characterized in that, In step S1, the power of the corona treatment is 120-160W.

7. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 5, characterized in that, In step S2, the temperature of the free radical polymerization reaction is 75-85℃, and the reaction time is 6-8h. The low-speed stirring time after adding glycerol esterified polymerized rosin, polyether modified organosilicon and composite crosslinking agent is 30-45 min.

8. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 5, characterized in that, In step S3, the coating method is comma blade coating, and the coating speed is 80-120m / min; The temperature gradients for the segmented baking are 70℃, 85℃, 95℃ and 80℃ respectively.

9. The high initial tack and high holding power movable BOPP pressure-sensitive tape according to claim 5, characterized in that, In step S4, the temperature for constant temperature curing is 45-50℃, and the curing time is 24-36h.

10. The application of a high-ring initial tack, high-holding-force removable BOPP pressure-sensitive tape according to any one of claims 1-4 in the fields of temporary fixing of electronic products, label positioning, board bonding, temporary bundling or surface protection.