Preparation method of high-breathability, low-sensitivity and high-viscosity hot melt adhesive for protective adhesive tape

Abstract

The invention discloses a preparation method of a high-breathability, low-sensitivity and high-viscosity hot melt adhesive for a protective adhesive tape, and relates to the technical field of hot melt adhesives. The preparation method comprises the following steps: carrying out epoxidation treatment on the block copolymer; then carrying out graft modification treatment on the epoxidized block copolymer to obtain a graft modified block copolymer; then adding the graft modified block copolymer and tackifying resin into the reaction kettle, and stirring for 1-2 hours at 150-160 DEG C under the protection of nitrogen; adding a plasticizer and an antioxidant into the reaction kettle, heating to 180-190 DEG C under the protection of nitrogen, and stirring for 1-2 hours; then adding a filling agent into the reaction kettle, and continuously stirring for 2-4 hours at 180-190 DEG C under the protection of nitrogen to obtain a pre-product; and finally, carrying out vacuum defoamation on the pre-product, discharging and cooling to obtain the hot melt adhesive. The high-breathability, low-sensitivity and high-viscosity hot melt adhesive prepared by the invention is excellent in breathability, low in sensitization to a human body, high in viscosity, not easy to fall off, simple in process and wide in application value.

Description

Technical Field

[0001] The present application relates to the technical field of hot melt adhesives, and in particular to a method for preparing a highly breathable, low-sensitivity, and high-viscosity hot melt adhesive for use in protective tapes. Background Art

[0002] Medical hot melt adhesive is an adhesive used in medical supplies. It is hot-melt and pressure-sensitive. It is used in various links such as surgery, monitoring, and diagnosis, and mainly plays the role of fixing and bonding. Common products made with medical hot melt adhesives include tapes, dressings, etc. Medical hot melt adhesive products are not only required not to cause allergic reactions to the skin; they also require good breathability, allowing the skin to breathe normally after being covered with adhesive products. In addition, the human body's natural perspiration system causes medical tapes to fall off easily during use. Therefore, medical hot melt adhesive products also need to adapt to the needs of most people's skin types and maintain a certain degree of adhesion even in humid or stuffy environments.

[0003] When conventional hot-melt pressure-sensitive adhesives are used as medical tapes, the formula components and proportions are simply adjusted, and then the components are simply mixed together. There is little involvement of raw material grafting modification and other treatments. Therefore, the performance will be compromised and the ideal effect required by users cannot be achieved.

[0004] A Chinese patent with publication number CN 117701202A discloses a medical tape adhesive and a preparation method thereof, comprising the following components: natural rubber, thermoplastic styrene-butadiene rubber, rosin resin, maleic terpene resin, filler, additive, and solvent oil. The adhesive has good bonding properties and can maintain a high peel strength for a long time under high temperature and high humidity.

[0005] However, the above-mentioned medical tape adhesive does not involve raw material grafting and modification treatment, and its performance does not fully integrate the three main aspects of breathability, low sensitivity and high adhesion, so there is still room for improvement. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present application provides a method for preparing a highly breathable, low-sensitivity and high-viscosity hot melt adhesive for protective tape, wherein the block copolymer is first epoxidized; then the epoxidized block copolymer is cross-linked and modified to obtain a grafted modified block copolymer; finally, the grafted modified block copolymer is used as the main component, combined with a tackifying resin, a plasticizer, an antioxidant, and a filler to obtain a highly breathable, low-sensitivity and high-viscosity hot melt adhesive with a completely new structure. The hot melt adhesive has excellent comprehensive performance and has broad application value.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: First, formic acid and hydrogen peroxide are added successively to the block copolymer dissolved in organic solvent A, and stirred for 1 to 2 hours to perform epoxidation treatment to obtain the epoxidized block copolymer, and the epoxidized block copolymer is washed, precipitated and dried; Then, under nitrogen protection, the epoxidized block copolymer dissolved in the organic solvent B is heated to 70-80°C, and then a base catalyst is added thereto, and stirring is started; Then, the D-mannose solution is added dropwise to the dissolved epoxidized block copolymer while stirring for 1.5 to 2.5 hours, and after the addition is completed, the mixture is stirred at 70 to 80° C. for 2 to 3 hours to obtain a graft-modified block copolymer; Then, the obtained graft-modified block copolymer and tackifying resin were added into the reaction kettle, and stirred at 150-160° C. for 1-2 hours under nitrogen protection; Then add plasticizer and antioxidant to the reactor, heat to 180-190°C under nitrogen protection, and stir for 1-2 hours; Then, filler was added into the reactor, and stirring was continued at 180-190° C. for 2-4 hours under nitrogen protection to obtain a pre-product. Finally, the pre-product was vacuum degassed and discharged and cooled to obtain the hot melt adhesive.

[0008] Beneficial technical effects: The present invention firstly epoxidizes the carbon-carbon double bonds in the block copolymer into epoxy groups, making it easier to carry out graft modification; then D-mannose containing a large number of hydroxyl groups in the molecule is grafted onto the epoxidized block copolymer, making the prepared graft-modified block copolymer more hydrophilic and having enhanced viscosity. Therefore, a large number of hydroxyl groups will also exist in the hot melt adhesive made with the graft-modified block copolymer as the main component, greatly enhancing the hot melt adhesive's tack retention and peel strength.

[0009] A highly breathable, low-sensitivity, high-viscosity hot melt adhesive with a new structure is obtained by combining tackifying resin, plasticizer, antioxidant and filler. The filler used is modified mesoporous silica modified by silane coupling agent. After modification, it can be more evenly dispersed in the hot melt adhesive system. At the same time, because the modified mesoporous silica has a large specific surface area and a porous structure, it can fully improve the water absorption and air permeability of the hot melt adhesive.

[0010] At the same time, the ingredients used in the hot melt adhesive prepared in the present application are all low-allergenic substances, so the prepared hot melt adhesive has excellent comprehensive properties of high air permeability, low sensitivity and high viscosity, and has broad application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the reaction process of epoxidation and grafting modification of block copolymers.

[0012] Figure 2is the chemical structural formula of the graft-modified SBS block copolymer prepared in Example 1.

[0013] Figure 3 It is an overall flow chart for preparing the highly breathable, low-sensitivity and high-viscosity hot melt adhesive. DETAILED DESCRIPTION

[0014] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the embodiments. However, this should not be understood as the scope of the present application being limited to the following examples. Without departing from the above-mentioned method ideas of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0015] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit the application.

[0016] As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0017] The technical solution provided by this application is: like Figure 3 As shown, a method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: First, formic acid and hydrogen peroxide are added successively to the block copolymer dissolved in organic solvent A, and stirred for 1 to 2 hours to perform epoxidation treatment to obtain the epoxidized block copolymer, and the epoxidized block copolymer is washed, precipitated and dried; Then, under nitrogen protection, the epoxidized block copolymer dissolved in the organic solvent B is heated to 70-80°C, and then a base catalyst is added thereto, and stirring is started; Then, the D-mannose solution is added dropwise to the dissolved epoxidized block copolymer while stirring for 1.5 to 2.5 hours, and after the addition is completed, the mixture is stirred at 70 to 80° C. for 2 to 3 hours to obtain a graft-modified block copolymer; Then, the obtained graft-modified block copolymer and tackifying resin were added into the reaction kettle, and stirred at 150-160° C. for 1-2 hours under nitrogen protection; Then add plasticizer and antioxidant to the reactor, heat to 180-190°C under nitrogen protection, and stir for 1-2 hours; Then, filler was added into the reactor, and stirring was continued at 180-190° C. for 2-4 hours under nitrogen protection to obtain a pre-product. Finally, the pre-product was vacuum degassed and discharged and cooled to obtain the hot melt adhesive.

[0018] In a possible implementation, the structure of the block copolymer includes: ; Wherein R represents a substituent on the carbon-carbon double bond, including any one of hydrogen (H) and methyl (-CH3); a is an integer in the range of 80 to 200; b is an integer in the range of 500 to 1200; c is an integer in the range of 80 to 200.

[0019] In a possible implementation, the organic solvent A includes one or more of cyclohexane, ethylene dichloride and toluene.

[0020] In a possible implementation, the mass ratio of the block copolymer, the organic solvent A, the formic acid, and the hydrogen peroxide is: (30-40): (40-50): (10-15): (10-20).

[0021] In a possible implementation, the structure of the epoxidized block copolymer includes: ; Wherein R represents a substituent on the carbon-carbon double bond, including any one of hydrogen (H) and methyl (-CH3); a is an integer in the range of 80 to 200; b is an integer in the range of 500 to 1200; c is an integer in the range of 80 to 200.

[0022] In a possible implementation, the organic solvent B includes one or more of ethyl acetate, acetone and xylene.

[0023] In a possible implementation, the base catalyst is any one of triethylamine and N,N-dimethylcyclohexylamine.

[0024] In a possible implementation, the mass ratio of the epoxidized block copolymer, the organic solvent B, the D-mannose solution, and the base catalyst is: (30-40): (40-50): (15-25): (3-5).

[0025] In a possible implementation, the structure of the graft-modified block copolymer includes: ;

[0026] One or two of the following: wherein R represents a substituent on a carbon-carbon double bond, including any one of hydrogen (H) and methyl (-CH3); a is an integer in the range of 80 to 200; b is an integer in the range of 500 to 1200; c is an integer in the range of 80 to 200.

[0027] The reaction process of the block copolymer epoxidation and graft modification is as follows: Figure 1 shown.

[0028] In a possible implementation, the tackifying resin includes one or more of terpene resin, rosin resin and petroleum resin.

[0029] In a possible implementation, the plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, tricresyl phosphate and trioctyl phosphate.

[0030] In a possible implementation, the antioxidant includes one or more of aromatic amine antioxidants, hindered phenol antioxidants, and thioester antioxidants.

[0031] In a possible implementation, the filler is modified mesoporous silica.

[0032] In a possible implementation, the modifier used in the modified mesoporous silica includes one or both of silane coupling agent KH-560 and silane coupling agent KH-570.

[0033] In a possible implementation, the modified mesoporous silica is spherical, and has an average particle size of 200-300 nm.

[0034] In a possible implementation, the method for preparing the modified mesoporous silica includes: First, add mesoporous silica into a high-speed mixer and start stirring at room temperature; Then, the silane coupling agent is sprayed into the stirred mesoporous silica in the form of a spray, and stirred at room temperature for 3-5 minutes to obtain the initially modified mesoporous silica, wherein the mass ratio of the silane coupling agent to the mesoporous silica is controlled at (0.5-1):100; Finally, the initially modified mesoporous silica is heated to 100-120°C, stirred for 10-30 minutes, and cooled to obtain the modified mesoporous silica.

[0035] In a possible implementation, the mass ratio of the graft-modified block copolymer, tackifying resin, plasticizer, antioxidant, and filler is: (40-50): (20-30): (10-15): (0.2-1): (15-25).

[0036] The experimental raw materials used in this application come from the following sources: Block copolymer: Shanghai Jizhi Biochemical Technology Co., Ltd.; Formic acid: Jinan Century Tongda Chemical Co., Ltd. Hydrogen peroxide: Sinopharm Group; Organic solvent A: Jiangsu Bosite Chemical Technology Co., Ltd.; D-mannose: Shanghai Yuanye Biotechnology Co., Ltd.; Alkaline catalyst: Jiangsu Pulex Biotechnology Co., Ltd.; Organic solvent B: Jiangsu Bosite Chemical Technology Co., Ltd.; Tackifying resin: Jiangsu Runfeng Synthetic Technology Co., Ltd.; Plasticizer: Jiangsu Bosite Chemical Technology Co., Ltd.; Antioxidant: Jiangsu Bosite Chemical Technology Co., Ltd.; Mesoporous silica: Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.; Silane coupling agent: Jiangsu Bosite Chemical Technology Co., Ltd.

[0037] The following will describe in detail a method for preparing a highly breathable, low-sensitivity, and high-viscosity hot melt adhesive for protective tape provided by the present application in combination with different embodiments.

[0038] Embodiment 1:

[0039] A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SBS block copolymer in cyclohexane, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SBS block copolymer, cyclohexane, formic acid and hydrogen peroxide is 30:40:15:15; 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in ethyl acetate, heat to 70°C, then add triethylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SBS block copolymer while stirring within 2 hours. After the addition was completed, stirring was continued for 2 hours to obtain a graft-modified SBS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SBS block copolymer, ethyl acetate, D-mannose solution, and triethylamine is 30:40:25:5; The structure of the obtained graft-modified SBS block copolymer is as follows: Figure 2 shown.

[0040] 4. Then, the obtained graft-modified SBS block copolymer and terpene resin were added into the reaction kettle, and stirred at 150° C. for 1.5 hours under nitrogen protection; 5. Then add dioctyl phthalate and aromatic amine antioxidant into the reactor, heat to 180°C under nitrogen protection, and stir for 1 hour; 6. Then, add KH-560 modified mesoporous silica (the mass ratio of KH-560 to mesoporous silica is 0.5:100) into the reactor, continue stirring at 180° C. for 2 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool the product to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the graft-modified SBS block copolymer, terpene resin, dioctyl phthalate, aromatic amine antioxidant, and KH-560 modified mesoporous silica is 45:25:10:1:19.

[0041] Embodiment 2:

[0042] A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SBS block copolymer in ethylene dichloride, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 1 hour to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SBS block copolymer, ethylene dichloride, formic acid and hydrogen peroxide is 35:40:10:15; 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in acetone, heat to 75°C, then add N,N-dimethylcyclohexylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SBS block copolymer while stirring within 1.5 hours. After the addition was completed, stirring was continued for 2.5 hours to obtain a graft-modified SBS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SBS block copolymer, acetone, D-mannose solution, and N,N-dimethylcyclohexylamine is 35:40:20:5; 4. Then, the obtained graft-modified SBS block copolymer and rosin resin were added into the reaction kettle, and stirred at 160°C for 1 hour under nitrogen protection; 5. Then add dibutyl phthalate and hindered phenol antioxidant into the reactor, heat to 185°C under nitrogen protection, and stir for 1 hour; 6. Then, add KH-570 modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 0.5:100) into the reactor, continue stirring at 185° C. for 2.5 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool it to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the graft-modified SBS block copolymer, rosin resin, dibutyl phthalate, hindered phenol antioxidant, and KH-570 modified mesoporous silica is 40:30:10:0.5:19.5.

[0043] Embodiment 3:

[0044] A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SIS block copolymer in toluene, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SIS block copolymer, toluene, formic acid and hydrogen peroxide is 40:40:10:10; 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in xylene, heat to 80°C, then add triethylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SIS block copolymer while stirring within 2 hours. After the addition was completed, stirring was continued for 3 hours to obtain a graft-modified SIS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SIS block copolymer, xylene, D-mannose solution, and triethylamine is 30:42:25:3; 4. Then, add the prepared graft-modified SIS block copolymer and petroleum resin into the reactor and stir at 150°C for 2 hours under nitrogen protection; 5. Then add dioctyl adipate and thioester antioxidant into the reactor, heat to 180°C under nitrogen protection, and stir for 1.5 hours; 6. Then, add KH-570 modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 1:100) into the reactor, continue stirring at 180° C. for 2.5 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool it to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the graft-modified SIS block copolymer, petroleum resin, dioctyl adipate, thioester antioxidant, and KH-570 modified mesoporous silica is 45:25:10:0.5:19.5.

[0045] Embodiment 4: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SIS block copolymer in cyclohexane, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SIS block copolymer, cyclohexane, formic acid and hydrogen peroxide is 30:40:10:20; 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in ethyl acetate, heat to 80°C, then add N,N-dimethylcyclohexylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SIS block copolymer while stirring within 2.5 hours. After the addition was completed, stirring was continued for 2 hours to obtain a graft-modified SIS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SIS block copolymer, ethyl acetate, D-mannose solution, and N,N-dimethylcyclohexylamine is 38:42:16:4; 4. Then, the prepared graft-modified SIS block copolymer and terpene resin were added into the reactor, and stirred at 160° C. for 1 hour under nitrogen protection; 5. Then add tricresyl phosphate and aromatic amine antioxidant into the reactor, heat to 185°C under nitrogen protection, and stir for 1 hour; 6. Then, add KH-570 modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 0.5:100) into the reactor, continue stirring at 185° C. for 2 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool it to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the graft-modified SIS block copolymer, terpene resin, tricresyl phosphate, aromatic amine antioxidant, and KH-570-modified mesoporous silica is 45:20:12:0.5:22.5.

[0046] Embodiment 5: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SBS block copolymer in ethylene dichloride, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 1.5 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SBS block copolymer, ethylene dichloride, formic acid and hydrogen peroxide is: 32:42:12:14; 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in acetone, heat to 70°C, then add triethylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SBS block copolymer while stirring within 1.5 hours. After the addition was completed, stirring was continued for 3 hours to obtain a graft-modified SBS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SBS block copolymer, acetone, D-mannose solution, and triethylamine is 32:48:15:5; 4. Then, the obtained graft-modified SBS block copolymer and rosin resin were added into the reaction kettle, and stirred at 155°C for 1.5 hours under nitrogen protection; 5. Then add trioctyl phosphate and hindered phenol antioxidant into the reactor, heat to 180°C under nitrogen protection, and stir for 2 hours; 6. Then, add KH-560 modified mesoporous silica (the mass ratio of KH-560 to mesoporous silica is 1:100) into the reactor, continue stirring at 180° C. for 2.5 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool the product to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the graft-modified SBS block copolymer, rosin resin, trioctyl phosphate, hindered phenol antioxidant, and KH-560 modified mesoporous silica is 45:24:12:0.5:18.5.

[0047] Embodiment 6: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SIS block copolymer in toluene, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 1.5 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SIS block copolymer, toluene, formic acid and hydrogen peroxide is 30:44:10:16; 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in xylene, raise the temperature to 75°C, then add N,N-dimethylcyclohexylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SIS block copolymer while stirring within 2 hours. After the addition was completed, stirring was continued for 3 hours to obtain a graft-modified SIS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SIS block copolymer, xylene, D-mannose solution, and N,N-dimethylcyclohexylamine is 36:44:15:5; 4. Then, add the prepared graft-modified SIS block copolymer and petroleum resin into the reactor and stir at 150°C for 2 hours under nitrogen protection; 5. Then add dioctyl phthalate and thioester antioxidant into the reactor, heat to 190°C under nitrogen protection, and stir for 1 hour; 6. Then, add KH-570 modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 1:100) into the reactor, continue stirring at 190° C. for 2 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool the product to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the graft-modified SIS block copolymer, petroleum resin, dioctyl phthalate, thioester antioxidant, and KH-570 modified mesoporous silica is 46:26:11:1:16.

[0048] Comparative Example 1: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SBS block copolymer in cyclohexane, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SBS block copolymer, cyclohexane, formic acid and hydrogen peroxide is 30:40:15:15; 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in ethyl acetate, heat to 70°C, then add triethylamine and start stirring; 3. Then, ethanol was added dropwise to the epoxidized SBS block copolymer while stirring within 2 hours. After the addition was completed, stirring was continued for 2 hours to obtain a modified SBS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SBS block copolymer, ethyl acetate, ethanol and triethylamine is 30:40:25:5; 4. Then, add the prepared modified SBS block copolymer and terpene resin into the reactor and stir at 150°C for 1.5 hours under nitrogen protection; 5. Then add dioctyl phthalate and aromatic amine antioxidant into the reactor, heat to 180°C under nitrogen protection, and stir for 1 hour; 6. Then, add KH-560 modified mesoporous silica (the mass ratio of KH-560 to mesoporous silica is 0.5:100) into the reactor, continue stirring at 180° C. for 2 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and cool the product to obtain the hot melt adhesive; In the above steps 4 to 6, the mass ratio of the modified SBS block copolymer, terpene resin, dioctyl phthalate, aromatic amine antioxidant, and KH-560 modified mesoporous silica is 45:25:10:1:19.

[0049] Comparative Example 2: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SIS block copolymer in cyclohexane, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SIS block copolymer, cyclohexane, formic acid and hydrogen peroxide is 30:40:10:20; 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in ethyl acetate, heat to 80°C, then add N,N-dimethylcyclohexylamine and start stirring; 3. Then, the D-mannose solution was added dropwise to the epoxidized SIS block copolymer while stirring within 2.5 hours. After the addition was completed, stirring was continued for 2 hours to obtain a graft-modified SIS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SIS block copolymer, ethyl acetate, D-mannose solution, and N,N-dimethylcyclohexylamine is 38:42:16:4; 4. Then, the prepared graft-modified SIS block copolymer and terpene resin were added into the reactor, and stirred at 160° C. for 1 hour under nitrogen protection; 5. Then add tricresyl phosphate and aromatic amine antioxidant into the reactor, heat to 185°C under nitrogen protection, and stir for 1 hour; 6. Then, talcum powder was added to the reaction kettle, and stirring was continued at 185° C. for 2 hours under nitrogen protection to obtain a pre-product. Finally, the pre-product was vacuum degassed and discharged and cooled to obtain the hot melt adhesive. In the above steps 4 to 6, the mass ratio of the graft-modified SIS block copolymer, terpene resin, tricresyl phosphate, aromatic amine antioxidant, and talc is 45:20:12:0.5:22.5.

[0050] Comparative Example 3: A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for a protective tape comprises the following steps: 1. Dissolve the SIS block copolymer in toluene, add formic acid and hydrogen peroxide successively, stir and react at room temperature for 1.5 hours to obtain an epoxidized block copolymer, and wash, precipitate and dry it; In the above step 1, the mass ratio of the SIS block copolymer, toluene, formic acid and hydrogen peroxide is 30:44:10:16; 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in xylene, raise the temperature to 75°C, then add N,N-dimethylcyclohexylamine and start stirring; 3. Then, ethanol was added dropwise to the epoxidized SIS block copolymer with stirring within 2 hours, and stirring was continued for 3 hours after the addition was completed to obtain a graft-modified SIS block copolymer; In the above steps 2-3, the mass ratio of the epoxidized SIS block copolymer, xylene, ethanol, and N,N-dimethylcyclohexylamine is 36:44:15:5; 4. Then, add the prepared graft-modified SIS block copolymer and petroleum resin into the reactor and stir at 150°C for 2 hours under nitrogen protection; 5. Then add dioctyl phthalate and thioester antioxidant into the reactor, heat to 190°C under nitrogen protection, and stir for 1 hour; 6. Then, talcum powder was added to the reaction kettle, and stirring was continued at 190° C. for 2 hours under nitrogen protection to obtain a pre-product. Finally, the pre-product was vacuum degassed and discharged and cooled to obtain the hot melt adhesive. In the above steps 4 to 6, the mass ratio of the graft-modified SIS block copolymer, petroleum resin, dioctyl phthalate, thioester antioxidant and talc is 46:26:11:1:16.

[0051] With reference to YY / T0148-2006, the viscosity test method is used to test the persistence and peel strength of the highly breathable, low-sensitivity and high-viscosity hot melt adhesive. The water vapor permeability test method is used to characterize the air permeability of the highly breathable, low-sensitivity and high-viscosity hot melt adhesive by the water vapor permeation every 24 hours.

[0052] With reference to GB / T 16886.1-2022, the allergenicity of the prepared highly breathable, low-sensitivity and high-viscosity hot melt adhesive was evaluated by whether it was allergenic.

[0053] Table 1 Performance test results of high air permeability, low sensitivity and high viscosity hot melt adhesives prepared in Examples 1-6 and Comparative Examples 1-3

[0054] As can be seen from Table 1, the persistent adhesion, 180° peel strength and air permeability of Examples 1-6 are better than those of Comparative Examples 1-3. This is because the highly breathable, low-sensitivity and high-viscosity hot melt adhesive prepared by the present application grafts D-mannose containing a large number of hydroxyl groups in the molecule onto the epoxidized block copolymer, making the prepared grafted modified block copolymer more hydrophilic and the viscosity is enhanced. Therefore, a large number of hydroxyl groups will also exist in the hot melt adhesive prepared with the grafted modified block copolymer as the main component, which greatly enhances the persistent adhesion and peel strength of the hot melt adhesive.

[0055] Moreover, the filler used in the highly breathable, low-sensitivity and high-viscosity hot melt adhesive prepared in the present application is modified mesoporous silica obtained by modification with a silane coupling agent. Because of the modification, it can be more evenly dispersed in the hot melt adhesive system. At the same time, since the modified mesoporous silica has a large specific surface area and a porous structure, it can fully improve the water absorption and air permeability of the hot melt adhesive.

[0056] In addition, since the ingredients used in the highly breathable, low-sensitivity, and high-viscosity hot melt adhesive prepared in the present application are all low-allergenic substances, neither the embodiments nor the comparative examples are allergenic.

[0057] The above results show and describe the basic principles and main features of the present application as well as the advantages of the present application.

[0058] Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection sought in the present application is defined by the equivalents of the attached claims.

Claims

1. A method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape, characterized in that: The steps include: First, formic acid and hydrogen peroxide are added successively to the block copolymer dissolved in organic solvent A, and stirred for 1 to 2 hours to perform epoxidation treatment to obtain the epoxidized block copolymer, and the epoxidized block copolymer is washed, precipitated and dried; Then, under nitrogen protection, the epoxidized block copolymer dissolved in the organic solvent B is heated to 70-80°C, and then a base catalyst is added thereto, and stirring is started; Then, the D-mannose solution is added dropwise to the dissolved epoxidized block copolymer while stirring for 1.5 to 2.5 hours, and after the addition is completed, the mixture is stirred at 70 to 80° C. for 2 to 3 hours to obtain a graft-modified block copolymer; Then, the obtained graft-modified block copolymer and tackifying resin were added into the reaction kettle, and stirred at 150-160° C. for 1-2 hours under nitrogen protection; Then add plasticizer and antioxidant to the reactor, heat to 180-190°C under nitrogen protection, and stir for 1-2 hours; Then, filler was added into the reactor, and stirring was continued at 180-190° C. for 2-4 hours under nitrogen protection to obtain a pre-product. Finally, the pre-product was vacuum degassed and discharged and cooled to obtain the hot melt adhesive.

2. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The structure of the block copolymer comprises: ； Wherein R represents a substituent on the carbon-carbon double bond, including any one of hydrogen and methyl; a is an integer in the range of 80 to 200; b is an integer in the range of 500 to 1200; c is an integer in the range of 80 to 200.

3. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The organic solvent A includes one or more of cyclohexane, ethylene dichloride and toluene; the mass ratio of the block copolymer, organic solvent A, formic acid and hydrogen peroxide is: (30-40): (40-50): (10-15): (10-20); the organic solvent B includes one or more of ethyl acetate, acetone and xylene; the structure of the epoxidized block copolymer includes: ； Wherein R represents a substituent on the carbon-carbon double bond, including any one of hydrogen and methyl; a is an integer in the range of 80 to 200; b is an integer in the range of 500 to 1200; c is an integer in the range of 80 to 200.

4. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The base catalyst is any one of triethylamine and N,N-dimethylcyclohexylamine; the mass ratio of the epoxidized block copolymer, the organic solvent B, the D-mannose solution, and the base catalyst is: (30-40): (40-50): (15-25): (3-5); the structure of the graft-modified block copolymer includes: ； wherein R represents a substituent on a carbon-carbon double bond, including any one of hydrogen and methyl; a is an integer in the range of 80 to 200; b is an integer in the range of 500 to 1200; and c is an integer in the range of 80 to 200.

5. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The tackifying resin includes one or more of terpene resin, rosin resin and petroleum resin.

6. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, tricresyl phosphate and trioctyl phosphate.

7. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The antioxidant includes one or more of aromatic amine antioxidants, hindered phenol antioxidants, and thioester antioxidants.

8. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The filler is modified mesoporous silica; the modifier used in the modified mesoporous silica includes one or two of silane coupling agent KH-560 and silane coupling agent KH-570; the modified mesoporous silica is spherical, and the average particle size is 200-300nm.

9. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 8, characterized in that: The preparation method of the modified mesoporous silica comprises: First, add mesoporous silica into a high-speed mixer and start stirring at room temperature; Then, the silane coupling agent is sprayed into the stirred mesoporous silica in the form of a spray, and stirred at room temperature for 3-5 minutes to obtain the initially modified mesoporous silica, wherein the mass ratio of the silane coupling agent to the mesoporous silica is controlled at (0.5-1):100; Finally, the initially modified mesoporous silica is heated to 100-120°C, stirred for 10-30 minutes, and cooled to obtain the modified mesoporous silica.

10. The method for preparing a highly breathable, low-sensitivity, high-viscosity hot melt adhesive for protective tape according to claim 1, characterized in that: The mass ratio of the graft modified block copolymer, tackifying resin, plasticizer, antioxidant and filler is: (40-50): (20-30): (10-15): (0.2-1): (15-25).

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