Preparation method of a highly breathable, low-sensitivity and high-adhesion hot melt adhesive for protective tape

Abstract

The present application discloses a preparation method of a highly breathable, low-sensitivity and highly adhesive hot melt adhesive for protective tapes, which relates to the technical field of hot melt adhesives. The preparation method includes: first, subjecting the block copolymer to epoxidation treatment; then, carrying out graft modification treatment on the epoxidized block copolymer to obtain a graft-modified block copolymer; next, adding the graft-modified block copolymer and a tackifying resin into a reaction kettle, and stirring at 150-160°C for 1-2 hours under nitrogen protection; then, adding a plasticizer and an antioxidant into the reaction kettle, heating to 180-190°C under nitrogen protection, and stirring for 1-2 hours; subsequently, adding a filler into the reaction kettle, and continuing to stir at 180-190°C for 2-4 hours under nitrogen protection to obtain a pre-product; finally, subjecting the pre-product to vacuum degassing and then discharging and cooling to obtain the hot melt adhesive. The highly breathable, low-sensitivity and highly adhesive hot melt adhesive prepared by the present application has excellent breathability, low sensitization to the human body, high viscosity and is not easy to fall off, and has a simple process and broad application value.

Description

Technical Field

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

[0002] Medical hot melt adhesives are adhesives used in medical supplies, with hot melt properties and pressure sensitivity, and are applied to various links such as surgery, monitoring, and diagnosis, mainly playing the role of fixation and bonding. Products prepared from common medical hot melt adhesives include tapes, dressings, etc. Medical hot melt adhesive products not only require no allergic reaction to the skin; but also need good air permeability to enable the skin to breathe normally after being covered by the adhesive product. In addition, the natural sweating system of the human body causes medical tapes to be easily detached during use. Therefore, medical hot melt adhesive products also need to meet the needs of most people's skin types and still maintain a certain adhesive force even in humid or stuffy environments.

[0003] When conventional hot melt pressure-sensitive adhesives are used as medical tapes, since only the formulation components and ratios are simply adjusted and then the components are simply mixed together, with less involvement in treatments such as graft modification of raw materials, the performance will be one-sided and unable to achieve the ideal effect required by users.

[0004] Chinese Patent No. CN 117701202A discloses a medical tape adhesive and its preparation method, including the following composition components: natural rubber, thermoplastic styrene-butadiene rubber, rosin resin, maleic terpene resin, filler, auxiliary agent, and solvent oil. This adhesive has good bonding performance and can maintain a relatively high peel strength for a long time under high temperature and high humidity.

[0005] However, the above medical tape adhesive does not involve graft modification treatment of raw materials, and in terms of performance, it does not fully integrate the three main aspects of air permeability, low sensitivity, and high adhesion, and there is still room for improvement. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present application provides a preparation method of a highly breathable, low-sensitivity and high-adhesion hot melt adhesive for protective tapes. First, the block copolymer is epoxidized; then the epoxidized block copolymer is crosslinked and modified to obtain a graft-modified block copolymer; finally, the graft-modified block copolymer is used as the main component, combined with a tackifying resin, a plasticizer, an antioxidant, and a filler to prepare a hot melt adhesive with a brand-new structure that has excellent comprehensive performance and broad application value.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] A preparation method of a highly breathable, low-sensitivity and high-adhesion hot melt adhesive for protective tapes, comprising the following steps:

[0009] First, formic acid and hydrogen peroxide are successively added to the block copolymer dissolved in organic solvent A, and stirred for 1 - 2 hours for epoxidation treatment to obtain an epoxidized block copolymer, which is then washed, precipitated, and dried;

[0010] Then, under nitrogen protection, the epoxidized block copolymer dissolved in organic solvent B is heated to 70 - 80 °C, and then an alkali catalyst is added thereto, and stirring is started;

[0011] Then, the D - mannose solution is added dropwise to the dissolved epoxidized block copolymer with stirring over 1.5 - 2.5 hours. After the addition is completed, stirring is continued at 70 - 80 °C for 2 - 3 hours to obtain a graft - modified block copolymer;

[0012] Next, the obtained graft - modified block copolymer and a tackifying resin are added to a reaction kettle, and stirred at 150 - 160 °C for 1 - 2 hours under nitrogen protection;

[0013] Then, a plasticizer and an antioxidant are added to the reaction kettle, and the temperature is raised to 180 - 190 °C under nitrogen protection, and stirred for 1 - 2 hours;

[0014] Subsequently, a filler is added to the reaction kettle, and stirring is continued at 180 - 190 °C for 2 - 4 hours under nitrogen protection to obtain a pre - product. Finally, the pre - product is vacuum - degassed and then discharged and cooled to obtain the hot - melt adhesive;

[0015] The structure of the block copolymer includes:

[0016] ;

[0017] 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 - 200; b is an integer in the range of 500 - 1200; c is an integer in the range of 80 - 200;

[0018] The filler is modified mesoporous silica; the modifier used for 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 - 300 nm;

[0019] The mass ratio of the graft - modified block copolymer, the tackifying resin, the plasticizer, the antioxidant, and the filler is: (40 - 50):(20 - 30):(10 - 15):(0.2 - 1):(15 - 25).

[0020] Beneficial technical effects:

[0021] In this application, the carbon-carbon double bonds in the block copolymer are first epoxidized to transform into epoxy groups, making it easier to carry out graft modification. Subsequently, 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 enhancing its viscosity. Therefore, a large number of hydroxyl groups also exist in the hot melt adhesive prepared with the graft-modified block copolymer as the main component, greatly enhancing the holding viscosity and peel strength of the hot melt adhesive.

[0022] A structurally new high-air permeability, low-sensitivity, and high-viscosity hot melt adhesive is prepared by combining a tackifying resin, a plasticizer, an antioxidant, and a filler. The filler used is modified mesoporous silica prepared by modifying 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, due to the large specific surface area and porous structure of the modified mesoporous silica, the water absorption and air permeability of the hot melt adhesive can be fully improved.

[0023] Meanwhile, the components selected for the hot melt adhesive prepared in this application are all low-sensitizing substances. Therefore, 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

[0024] Figure 1 It is a schematic diagram of the reaction process of the epoxidation and graft modification of the block copolymer.

[0025] Figure 2 It is the chemical structural formula of the graft-modified SBS block copolymer prepared in Example 1.

[0026] Figure 3 It is the overall flow chart for preparing the high-air permeability, low-sensitivity, and high-viscosity hot melt adhesive. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer and more understandable, the following will further elaborate on this application in combination with examples. However, this should not be construed as limiting the scope of this application to the following examples. Without departing from the above method concept of this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0028] In this application, the terms used are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0029] The singular forms "a" and "the" used in this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0030] The technical solution provided by this application is as follows:

[0031] As Figure 3 shown, a preparation method of a highly breathable, hypoallergenic and highly adhesive hot melt adhesive for protective tape includes the following steps:

[0032] First, formic acid and hydrogen peroxide are successively added to a block copolymer dissolved in organic solvent A, stirred for 1 - 2 hours for epoxidation treatment to obtain an epoxidized block copolymer, which is then washed, precipitated and dried;

[0033] Then, under nitrogen protection, the epoxidized block copolymer dissolved in organic solvent B is heated to 70 - 80 °C, and then an alkali catalyst is added thereto, and stirring is started;

[0034] Then, a D - mannose solution is added dropwise to the dissolved epoxidized block copolymer with stirring for 1.5 - 2.5 hours. After the addition is completed, stirring is continued at 70 - 80 °C for 2 - 3 hours to obtain a graft - modified block copolymer;

[0035] Next, the obtained graft - modified block copolymer and a tackifying resin are added to a reaction kettle and stirred at 150 - 160 °C for 1 - 2 hours under nitrogen protection;

[0036] Then, a plasticizer and an antioxidant are added to the reaction kettle, and the temperature is raised to 180 - 190 °C under nitrogen protection and stirred for 1 - 2 hours;

[0037] Subsequently, a filler is added to the reaction kettle, and stirring is continued at 180 - 190 °C for 2 - 4 hours under nitrogen protection to obtain a pre - product. Finally, the pre - product is vacuum - degassed and then discharged and cooled to obtain the hot melt adhesive.

[0038] In a possible implementation, the structure of the block copolymer includes:

[0039] ;

[0040] 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 - 200; b is an integer in the range of 500 - 1200; c is an integer in the range of 80 - 200.

[0041] In a possible implementation, the filler is modified mesoporous silica.

[0042] In a possible implementation, the modifier used for the modified mesoporous silica includes one or both of silane coupling agent KH - 560 and silane coupling agent KH - 570.

[0043] In a possible implementation, the modified mesoporous silica is spherical with an average particle size of 200 - 300 nm.

[0044] In one possible implementation, the preparation method of the modified mesoporous silica includes:

[0045] First, add the mesoporous silica to a high-speed blender and start stirring at room temperature;

[0046] Then, spray the silane coupling agent into the stirred mesoporous silica in the form of a spray, and stir at room temperature for 3 - 5 min to obtain preliminarily modified mesoporous silica, where the mass ratio of the silane coupling agent to the mesoporous silica is controlled at (0.5 - 1):100;

[0047] Finally, heat the preliminarily modified mesoporous silica to 100 - 120 °C, continue stirring for 10 - 30 min, and discharge and cool to obtain the modified mesoporous silica.

[0048] In one 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).

[0049] In one possible implementation, the organic solvent A includes one or more of cyclohexane, dichloroethane, and toluene.

[0050] In one possible implementation, the mass ratio of the block copolymer, organic solvent A, formic acid, and hydrogen peroxide is: (30 - 40):(40 - 50):(10 - 15):(10 - 20).

[0051] In one possible implementation, the structure of the epoxidized block copolymer includes:

[0052] ;

[0053] where 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 - 200; b is an integer in the range of 500 - 1200; c is an integer in the range of 80 - 200.

[0054] In one possible implementation, the organic solvent B includes one or more of ethyl acetate, acetone, and xylene.

[0055] In one possible implementation, the base catalyst is any one of triethylamine and N,N-dimethylcyclohexylamine.

[0056] In one possible implementation, the mass ratio of the epoxidized block copolymer, organic solvent B, D-mannose solution, and base catalyst is: (30 - 40):(40 - 50):(15 - 25):(3 - 5).

[0057] In a possible implementation, the structure of the graft-modified block copolymer includes:

[0058] and

[0059]

[0060] one or two of them; where 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.

[0061] The reaction process of epoxidation and graft modification of the above block copolymer is specifically as Figure 1 shown.

[0062] In a possible implementation, the tackifying resin includes one or more of terpene resin, rosin resin, and petroleum resin.

[0063] In a possible implementation, the plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, tricresyl phosphate, and trioctyl phosphate.

[0064] In a possible implementation, the antioxidant includes one or more of aromatic amine antioxidants, hindered phenol antioxidants, and thioester antioxidants.

[0065] The sources of the experimental raw materials used in this application are as follows:

[0066] Block copolymer: Shanghai Jizhi Biochemical Technology Co., Ltd.;

[0067] Formic acid: Jinan Century Tongda Chemical Industry Co., Ltd.;

[0068] Hydrogen peroxide: Sinopharm Group;

[0069] Organic solvent A: Jiangsu Bost Chemical Technology Co., Ltd.;

[0070] D-Mannose: Shanghai Yuanye Bio-Technology Co., Ltd.;

[0071] Alkaline catalyst: Jiangsu Pulesi Biotechnology Co., Ltd.;

[0072] Organic solvent B: Jiangsu Bost Chemical Technology Co., Ltd.;

[0073] Tackifying resin: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0074] Plasticizer: Jiangsu Bost Chemical Technology Co., Ltd.;

[0075] Antioxidant: Jiangsu Bost Chemical Technology Co., Ltd.;

[0076] Mesoporous silica: Jiangsu Xianfeng Nano Materials Technology Co., Ltd.;

[0077] Silane coupling agent: Jiangsu Bost Chemical Technology Co., Ltd.

[0078] The following will specifically describe a preparation method of a highly breathable, low-sensitivity and high-viscosity hot melt adhesive for protective tapes provided by the present application in combination with different embodiments.

[0079] Example 1:

[0080] A preparation method of a highly breathable, low-sensitivity and high-viscosity hot melt adhesive for protective tapes includes the following steps:

[0081] 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;

[0082] In the above step 1, the mass ratio of the SBS block copolymer, cyclohexane, formic acid and hydrogen peroxide is: 30:40:15:15;

[0083] 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in ethyl acetate, heat up to 70 °C, and then add triethylamine thereto and start stirring;

[0084] 3. Then, while stirring, drop the D-mannose solution into the epoxidized SBS block copolymer within 2 hours, and continue stirring for 2 hours after dropping to obtain a graft-modified SBS block copolymer;

[0085] 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;

[0086] The structure of the obtained graft-modified SBS block copolymer is as Figure 2 shown.

[0087] 4. Then, add the obtained graft-modified SBS block copolymer and terpene resin into the reaction kettle, and stir at 150 °C for 1.5 hours under nitrogen protection;

[0088] 5. Then, add dioctyl phthalate and aromatic amine antioxidant into the reaction kettle, heat up to 180 °C under nitrogen protection, and stir for 1 hour;

[0089] 6. Then add mesoporous silica modified by KH-560 (the mass ratio of KH-560 to mesoporous silica is 0.5:100) into the reaction kettle, continue to stir at 180 °C for 2 hours under nitrogen protection to obtain a pre-product, and finally carry out vacuum degassing on the pre-product and then discharge and cool it to obtain the hot melt adhesive;

[0090] In the above steps 4-6, 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.

[0091] Example 2:

[0092] A preparation method of a highly breathable, low-sensitivity and high-viscosity hot melt adhesive for protective tapes, comprising the following steps:

[0093] 1. Dissolve the SBS block copolymer in dichloroethane, 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;

[0094] In the above step 1, the mass ratio of the SBS block copolymer, dichloroethane, formic acid, and hydrogen peroxide is: 35:40:10:15;

[0095] 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in acetone, heat up to 75 °C, and then add N,N-dimethylcyclohexylamine to it and start stirring;

[0096] 3. Then drop the D-mannose solution into the epoxidized SBS block copolymer dropwise with stirring within 1.5 hours, and continue to stir for 2.5 hours after the dropping is completed to obtain a graft-modified SBS block copolymer;

[0097] 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;

[0098] 4. Then add the prepared graft-modified SBS block copolymer and rosin resin into the reaction kettle, and stir at 160 °C for 1 hour under nitrogen protection;

[0099] 5. Then add dibutyl phthalate and hindered phenol antioxidant into the reaction kettle, heat up to 185 °C under nitrogen protection, and stir for 1 hour;

[0100] 6. Then add mesoporous silica modified by KH-570 (the mass ratio of KH-570 to mesoporous silica is 0.5:100) into the reaction kettle, continue to stir at 185 °C for 2.5 hours under nitrogen protection to obtain a pre-product, and finally carry out vacuum degassing on the pre-product and then discharge and cool it to obtain the hot melt adhesive;

[0101] 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.

[0102] Example 3:

[0103] A preparation method of a highly breathable, low-sensitivity, and highly adhesive hot melt adhesive for protective tapes, comprising the following steps:

[0104] 1. Dissolve the SIS block copolymer in toluene, add formic acid and hydrogen peroxide successively, and stir at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate, and dry it;

[0105] In the above step 1, the mass ratio of the SIS block copolymer, toluene, formic acid, and hydrogen peroxide is: 40:40:10:10;

[0106] 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in xylene, heat it to 80 °C, and then add triethylamine thereto and start stirring;

[0107] 3. Then, while stirring, drop the D-mannose solution into the epoxidized SIS block copolymer within 2 hours, and continue stirring for 3 hours after the dropping is completed to obtain a graft-modified SIS block copolymer;

[0108] In the above steps 2 to 3, the mass ratio of the epoxidized SIS block copolymer, xylene, D-mannose solution, and triethylamine is: 30:42:25:3;

[0109] 4. Then, add the prepared graft-modified SIS block copolymer and petroleum resin to the reaction kettle, and stir at 150 °C for 2 hours under nitrogen protection;

[0110] 5. Then, add dioctyl adipate and thioester antioxidant to the reaction kettle, heat it to 180 °C under nitrogen protection, and stir for 1.5 hours;

[0111] 6. Then, add KH-570-modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 1:100) to the reaction kettle, 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 then discharge and cool it to obtain the hot melt adhesive;

[0112] 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.

[0113] Example 4:

[0114] A preparation method of a highly breathable, low-sensitivity and highly adhesive hot melt adhesive for protective tapes, comprising the following steps:

[0115] 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;

[0116] In the above step 1, the mass ratio of the SIS block copolymer, cyclohexane, formic acid, and hydrogen peroxide is: 30:40:10:20;

[0117] 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in ethyl acetate, heat up to 80 °C, and then add N,N-dimethylcyclohexylamine thereto, and start stirring;

[0118] 3. Then, while stirring, drop the D-mannose solution into the epoxidized SIS block copolymer within 2.5 hours, and continue to stir for 2 hours after dropping to obtain a graft-modified SIS block copolymer;

[0119] 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;

[0120] 4. Then, add the obtained graft-modified SIS block copolymer and terpene resin to the reaction kettle, and stir at 160 °C for 1 hour under nitrogen protection;

[0121] 5. Then, add tricresyl phosphate and aromatic amine antioxidants to the reaction kettle, heat up to 185 °C under nitrogen protection, and stir for 1 hour;

[0122] 6. Then, add KH-570-modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 0.5:100) to the reaction kettle, continue to stir at 185 °C for 2 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and discharge and cool it to obtain the hot melt adhesive;

[0123] In the above steps 4-6, the mass ratio of the graft-modified SIS block copolymer, terpene resin, tricresyl phosphate, aromatic amine antioxidants, and KH-570-modified mesoporous silica is: 45:20:12:0.5:22.5.

[0124] Example 5:

[0125] A preparation method of a highly breathable, low-sensitivity and highly adhesive hot melt adhesive for protective tapes, comprising the following steps:

[0126] 1. Dissolve the SBS block copolymer in dichloroethane, 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;

[0127] In the above step 1, the mass ratio of the SBS block copolymer, dichloroethane, formic acid, and hydrogen peroxide is: 32:42:12:14;

[0128] 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in acetone, heat up to 70 °C, then add triethylamine thereto, and start stirring;

[0129] 3. Then, while stirring, drop the D-mannose solution into the epoxidized SBS block copolymer within 1.5 hours. After the dropping is completed, continue stirring for 3 hours to obtain a graft-modified SBS block copolymer;

[0130] 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;

[0131] 4. Then, add the obtained graft-modified SBS block copolymer and rosin resin to the reaction kettle, and stir at 155 °C for 1.5 hours under nitrogen protection;

[0132] 5. Then, add trioctyl phosphate and a hindered phenol antioxidant to the reaction kettle, heat up to 180 °C under nitrogen protection, and stir for 2 hours;

[0133] 6. Then, add KH-560-modified mesoporous silica (the mass ratio of KH-560 to mesoporous silica is 1:100) to the reaction kettle, continue to stir at 180 °C for 2.5 hours under nitrogen protection to obtain a pre-product, and finally vacuum degas the pre-product and then discharge and cool it to obtain the hot melt adhesive;

[0134] In the above steps 4-6, 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.

[0135] Example 6:

[0136] A preparation method of a highly breathable, low-sensitivity and high-viscosity hot melt adhesive for protective tapes, comprising the following steps:

[0137] 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;

[0138] In Step 1 above, the mass ratio of the SIS block copolymer, toluene, formic acid, and hydrogen peroxide is: 30:44:10:16;

[0139] 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in xylene, heat up to 75 °C, then add N,N-dimethylcyclohexylamine thereto, and start stirring;

[0140] 3. Then, while stirring, dropwise add the D-mannose solution to the epoxidized SIS block copolymer within 2 hours. After the addition is complete, continue stirring for 3 hours to obtain the graft-modified SIS block copolymer;

[0141] In Steps 2-3 above, the mass ratio of the epoxidized SIS block copolymer, xylene, D-mannose solution, and N,N-dimethylcyclohexylamine is: 36:44:15:5;

[0142] 4. Next, add the obtained graft-modified SIS block copolymer and petroleum resin to the reaction kettle, and stir at 150 °C for 2 hours under nitrogen protection;

[0143] 5. Then, add dioctyl phthalate and thioester antioxidant to the reaction kettle, heat up to 190 °C under nitrogen protection, and stir for 1 hour;

[0144] 6. Then, add KH-570-modified mesoporous silica (the mass ratio of KH-570 to mesoporous silica is 1:100) to the reaction kettle, continue to stir at 190 °C for 2 hours under nitrogen protection to obtain the pre-product. Finally, vacuum degas the pre-product and then discharge and cool it to obtain the hot melt adhesive;

[0145] In Steps 4-6 above, 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.

[0146] Comparative Example 1:

[0147] A preparation method of a highly breathable, low-sensitivity, and high-viscosity hot melt adhesive for protective tapes, comprising the following steps:

[0148] 1. Dissolve the SBS block copolymer in cyclohexane, successively add formic acid and hydrogen peroxide, stir and react at room temperature for 2 hours to obtain the epoxidized block copolymer, and wash, precipitate, and dry it;

[0149] In Step 1 above, the mass ratio of the SBS block copolymer, cyclohexane, formic acid, and hydrogen peroxide is: 30:40:15:15;

[0150] 2. Under nitrogen protection, dissolve the epoxidized SBS block copolymer in ethyl acetate, heat it up to 70 °C, then add triethylamine to it and start stirring;

[0151] 3. Then, while stirring, slowly add ethanol dropwise to the epoxidized SBS block copolymer within 2 hours. After the addition is complete, continue stirring for 2 hours to obtain the modified SBS block copolymer;

[0152] 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;

[0153] 4. Next, add the obtained modified SBS block copolymer and terpene resin to the reaction kettle, and stir at 150 °C for 1.5 hours under nitrogen protection;

[0154] 5. Then, add dioctyl phthalate and aromatic amine antioxidant to the reaction kettle, heat it up to 180 °C under nitrogen protection, and stir for 1 hour;

[0155] 6. Then, add KH-560 modified mesoporous silica (the mass ratio of KH-560 to mesoporous silica is 0.5:100) to the reaction kettle, continue to stir at 180 °C for 2 hours under nitrogen protection to obtain the pre-product. Finally, degas the pre-product under vacuum and then discharge and cool it to obtain the hot melt adhesive;

[0156] In the above steps 4 - 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.

[0157] Comparative Example 2:

[0158] A preparation method of a highly breathable, low-sensitivity, and high-viscosity hot melt adhesive for protective tapes, comprising the following steps:

[0159] 1. Dissolve the SIS block copolymer in cyclohexane, add formic acid and hydrogen peroxide successively, and stir at room temperature for 2 hours to obtain an epoxidized block copolymer, and wash, precipitate, and dry it;

[0160] In the above step 1, the mass ratio of the SIS block copolymer, cyclohexane, formic acid, and hydrogen peroxide is: 30:40:10:20;

[0161] 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in ethyl acetate, heat it up to 80 °C, then add N,N-dimethylcyclohexylamine to it and start stirring;

[0162] 3. Then, while stirring, the D-mannose solution is added dropwise to the epoxidized SIS block copolymer within 2.5 hours. After the addition is complete, stirring is continued for 2 hours to obtain the graft-modified SIS block copolymer;

[0163] In the above steps 2 to 3, the mass ratio of the epoxidized SIS block copolymer, ethyl acetate, D-mannose solution, and N,N-dimethylcyclohexylamine is: 38:42:16:4;

[0164] 4. Next, the obtained graft-modified SIS block copolymer and terpene resin are added to the reaction kettle, and stirred at 160 °C for 1 hour under nitrogen protection;

[0165] 5. Then, tricresyl phosphate and aromatic amine antioxidant are added to the reaction kettle, and the temperature is raised to 185 °C under nitrogen protection, and stirred for 1 hour;

[0166] 6. Then, talcum powder is added to the reaction kettle, and stirring is continued at 185 °C for 2 hours under nitrogen protection to obtain the pre-product. Finally, the pre-product is vacuum degassed and then discharged and cooled to obtain the hot melt adhesive;

[0167] 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 talcum powder is: 45:20:12:0.5:22.5.

[0168] Comparative Example 3:

[0169] A preparation method of a highly breathable, low-sensitivity, and high-viscosity hot melt adhesive for protective tape, comprising the following steps:

[0170] 1. Dissolve the SIS block copolymer in toluene, add formic acid and hydrogen peroxide successively, and stir and react at room temperature for 1.5 hours to obtain the epoxidized block copolymer, and wash, precipitate, and dry it;

[0171] In the above step 1, the mass ratio of the SIS block copolymer, toluene, formic acid, and hydrogen peroxide is: 30:44:10:16;

[0172] 2. Under nitrogen protection, dissolve the epoxidized SIS block copolymer in xylene, raise the temperature to 75 °C, and then add N,N-dimethylcyclohexylamine thereto, and start stirring;

[0173] 3. Then, while stirring, ethanol is added dropwise to the epoxidized SIS block copolymer within 2 hours. After the addition is complete, stirring is continued for 3 hours to obtain the graft-modified SIS block copolymer;

[0174] In the above steps 2 to 3, the mass ratio of the epoxidized SIS block copolymer, xylene, ethanol, and N,N-dimethylcyclohexylamine is: 36:44:15:5;

[0175] 4. Next, add the prepared graft-modified SIS block copolymer and petroleum resin into the reaction kettle, and stir at 150 °C for 2 hours under nitrogen protection;

[0176] 5. Then, add dioctyl phthalate and thioester antioxidant into the reaction kettle, heat up to 190 °C under nitrogen protection, and stir for 1 hour;

[0177] 6. Then, add talcum powder into the reaction kettle, continue to stir at 190 °C for 2 hours under nitrogen protection to obtain the pre-product. Finally, degas the pre-product under vacuum and then discharge and cool it to obtain the hot melt adhesive;

[0178] In the above steps 4 - 6, the mass ratio of the graft-modified SIS block copolymer, petroleum resin, dioctyl phthalate, thioester antioxidant, and talcum powder is: 46:26:11:1:16.

[0179] Referring to YY / T0148 - 2006, using the viscosity test method, test the holding viscosity and peel strength of the highly breathable, low-sensitivity, and high-viscosity hot melt adhesive; using the water vapor permeability test method, characterize the breathability of the highly breathable, low-sensitivity, and high-viscosity hot melt adhesive by the water vapor permeation amount per 24 h.

[0180] Referring to GB / T 16886.1 - 2022, evaluate the sensitization of the prepared highly breathable, low-sensitivity, and high-viscosity hot melt adhesive by whether it causes sensitization.

[0181] Table 1 Performance test results of the highly breathable, low-sensitivity, and high-viscosity hot melt adhesives prepared in Examples 1 - 6 and Comparative Examples 1 - 3

[0182]

[0183] As can be seen from Table 1, the holding viscosity, 180° peel strength, and breathability of Examples 1 - 6 are all better than those of Comparative Examples 1 - 3. This is because in the highly breathable, low-sensitivity, and high-viscosity hot melt adhesive prepared in this application, D-mannose containing a large number of hydroxyl groups in the molecule is grafted onto the epoxy block copolymer, making the prepared graft-modified block copolymer more hydrophilic and enhancing the viscosity. Therefore, there will also be a large number of hydroxyl groups in the hot melt adhesive prepared with the graft-modified block copolymer as the main component, greatly enhancing the holding viscosity and peel strength of the hot melt adhesive.

[0184] Moreover, the filler used in the highly breathable, low-sensitivity, and high-viscosity hot melt adhesive prepared in this application is modified mesoporous silica prepared by modifying 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, due to the large specific surface area and porous structure of the modified mesoporous silica, the water absorption and breathability of the hot melt adhesive can be fully improved.

[0185] In addition, since the components selected for the highly breathable, hypoallergenic, and highly adhesive hot melt adhesive prepared in this application are all hypoallergenic substances, there is no allergenicity in both the examples and the comparative examples.

[0186] The above results show and describe the basic principles, main features, and advantages of this application.

[0187] Those skilled in the art should understand that this application is not limited by the above examples. The above examples and the descriptions in the specification only illustrate the principles of this application. Without departing from the spirit and scope of this application, this application will have various changes and improvements, and these changes and improvements all fall within the scope of this application claimed. The scope of protection claimed for this application is defined by the equivalents of the appended 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, a filler is added to the reactor, and stirring is continued at 180-190° C. for 2-4 hours under nitrogen protection to obtain a pre-product, and finally, the pre-product is vacuum degassed and discharged and cooled to obtain the hot melt adhesive; The structure of the block copolymer comprises: ； 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; c is an integer in the range of 80 to 200; The filler is modified mesoporous silica; The modifier used in the modified mesoporous silica includes one or both of silane coupling agent KH-560 and silane coupling agent KH-570; the modified mesoporous silica is spherical, and the average particle size is 200-300 nm; 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).

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 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.

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 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: and 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.

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 tackifying resin includes one or more of terpene resin, rosin resin and petroleum resin.

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 plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, tricresyl phosphate and trioctyl phosphate.

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 antioxidant includes one or more of aromatic amine antioxidants, hindered phenol antioxidants, and thioester antioxidants.

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 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.

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