Modified hot-melt pressure-sensitive adhesive and preparation method thereof

Abstract

The invention provides a modified hot-melt pressure-sensitive adhesive and a preparation method thereof. The modified hot-melt pressure-sensitive adhesive is prepared from the following components in parts by weight: 25 to 30 parts of modified SIS, 20 to 40 parts of a plasticizer, 40 to 60 parts of a tackifier, 0.5 to 1.0 part of an antioxidant, 0.5 to 1.0 part of an ultraviolet absorbent and 1 to 2 parts of a de-foaming agent. The preparation method of the modified hot-melt pressure-sensitive adhesive comprises the following steps: blending the modified SIS with the tackifier, the plasticizer, the antioxidant, the ultraviolet absorbent and the defoaming agent in parts by weight, heating and stirring to obtain the hot-melt pressure-sensitive adhesive. By modifying SIS, the hot-melt pressure-sensitive adhesive has dynamic disulfide bonds, the low-temperature performance and crack resistance of the hot-melt pressure-sensitive adhesive are improved, the dynamic disulfide bonds enable SIS to form a more complete cross-linked network structure in the hot-melt pressure-sensitive adhesive, and the viscosity performance of the hot-melt pressure-sensitive adhesive is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hot melt pressure sensitive adhesives, and in particular relates to a modified hot melt pressure sensitive adhesive and a preparation method thereof. Background Art

[0002] Hot melt pressure sensitive adhesive is the abbreviation of hot melt pressure sensitive adhesive. It refers to a hot melt adhesive that is sensitive to pressure, can connect the adherends with a little pressure, and does not require the use of solvents or other auxiliary means. It has the dual characteristics of heat-sensitive adhesive and pressure-sensitive adhesive. It is a solid adhesive without other solvents formed by melting and stirring with base resin as the main component, and adding tackifiers, plasticizers, antioxidants and other additives. Hot melt pressure sensitive adhesive is solid at room temperature, but when heated and melted to a certain degree, it will become a flowable, viscous liquid state. After cooling and solidification, it forms adhesion to the surface of the substrate, but will not pollute the surface of the substrate, and has a certain re-adhesive ability. Compared with traditional solvent-based adhesives, water-based adhesives and various other adhesives, hot melt pressure sensitive adhesive has the advantages of no pollution, fast coating speed, high degree of intelligence, and low product cost. The disadvantage is that it is significantly affected by temperature during use.

[0003] Hot melt pressure sensitive adhesive has a higher usage rate and a wider range of applications than solution type and emulsion type pressure sensitive adhesive. According to different application industries, it can be divided into hot melt pressure sensitive adhesive for label tape, hot melt pressure sensitive adhesive for sanitary products, hot melt pressure sensitive adhesive for medical consumables, and hot melt pressure sensitive adhesive for building waterproof membrane.

[0004] However, there are many problems with hot-melt pressure-sensitive adhesives during their use and service. For example, the colloid softens or melts under high temperature conditions, causing adhesive overflow or failure; the colloid is prone to aging under high temperature conditions, causing a decrease in peel strength; the performance is poor under low temperature conditions, and it is not easy to complete bonding with the adherend; the adhesive layer is prone to cracking or peeling off after being subjected to external force under low temperature conditions.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a modified hot melt pressure sensitive adhesive and a preparation method thereof to solve the above problems.

[0007] In order to achieve the above objectives, the present invention particularly adopts the following technical solutions:

[0008] The present invention first provides a modified hot melt pressure sensitive adhesive. The modified hot melt pressure sensitive adhesive comprises, by weight, 25-30 parts of modified SIS, 20-40 parts of plasticizer, 40-60 parts of tackifier, 0.5-1.0 parts of antioxidant, 0.5-1.0 parts of ultraviolet absorber and 1-2 parts of defoamer.

[0009] Preferably, the modified SIS is an SIS having a dynamic disulfide bond structure.

[0010] Optionally, the plasticizer includes naphthenic oil;

[0011] Preferably, the tackifier includes hydrogenated dicyclopentadiene petroleum resin;

[0012] Preferably, the antioxidant includes antioxidant 168 and / or antioxidant 3114;

[0013] Preferably, the ultraviolet absorber includes ultraviolet absorber 326;

[0014] Preferably, the defoamer includes dimethyl silicone oil.

[0015] The present invention also provides a preparation method of the modified hot melt pressure-sensitive adhesive, and the preparation method includes: blending the modified SIS, the tackifier, the plasticizer, the antioxidant, the ultraviolet absorber, and the defoamer according to parts by weight, heating, and stirring to obtain a hot melt pressure-sensitive adhesive.

[0016] Preferably, the blending includes: adding the plasticizer, the antioxidant, and the ultraviolet absorber into a stainless steel container, blending at 160 - 180 °C, then adding the modified SIS, stirring at a rotation speed of 1000 - 2000 r / min for 1 - 2 h to blend evenly, subsequently adding the tackifier, and continuing to stir at a rotation speed of 1000 - 2000 r / min for 30 - 60 min.

[0017] Preferably, the preparation method of the modified SIS includes the following steps:

[0018] S1: Heating and stirring 3,3'-dithiobis(propionic acid) (DPA) and 2-hydroxyethyl methacrylate (HEMA) under the catalysis of concentrated sulfuric acid for a first reaction to obtain a lipid intermediate LIM;

[0019] Optionally, step S1 satisfies one or more of the following conditions:

[0020] a. According to parts by weight, the 3,3'-dithiobis(propionic acid) (DPA) is 15 - 25 parts, the 2-hydroxyethyl methacrylate (HEMA) is 20 - 24 parts, and the concentrated sulfuric acid is 0.8 - 0.96 parts;

[0021] b. The target temperature of the heating is 85 - 95 °C;

[0022] c. The rotation speed of the stirring is 60 - 80 r / min;

[0023] d. The time of the first reaction is 1 - 2 h.

[0024] S2: Dissolving SIS in a solvent to obtain an SIS solution;

[0025] S3: Add the lipid intermediate LIM obtained in S1 and benzoyl peroxide (BPO) to the SIS solution obtained in S2, and perform a second reaction by heating and stirring to obtain a modified SIS solution; the temperature of the second reaction is 85 - 95 °C, and the reaction time is 2 - 6 h;

[0026] Preferably, the stirring speed is 60 - 80 r / min.

[0027] S4: Wash the modified SIS solution obtained in S3 with a detergent, filter the precipitate and dry it to obtain the modified SIS.

[0028] Preferably, the preparation method of the modified SIS further satisfies one or more of the following conditions:

[0029] e. In the step S1, the first reaction further includes: after the reaction is completed, cool the system to room temperature and let it stand for 24 - 72 h;

[0030] f. In the step S2, the solvent includes toluene and / or xylene;

[0031] g. The system composition of the second reaction in the step S3 includes: by weight, 5 - 10 parts of the SIS, 50 - 75 parts of the solvent, 0.5 - 1.5 parts of the LIM, and 0.15 - 0.25 parts of the BPO;

[0032] h. In the step S4, the detergent includes anhydrous methanol and / or anhydrous ethanol.

[0033] Furthermore, in the step S3, during the second reaction, introduce gas protection intermittently; preferably, the gas is nitrogen or argon; preferably, the number of intermittent introductions is 3 - 5 times.

[0034] The main purpose of the present invention is to construct a dynamic covalent bond structure of SIS and use it to prepare a hot melt pressure - sensitive adhesive, that is, synthesize a lipid intermediate LIM to modify SIS and use it to prepare a hot melt pressure - sensitive adhesive. This method can increase the adhesive properties of the hot melt pressure - sensitive adhesive, and at the same time improve the low - temperature performance and crack - resistance performance of the hot melt pressure - sensitive adhesive. The reaction mechanism of the preparation of LIM and the modification of SIS provided by the present invention is as follows:

[0035]

[0036] The esterification reaction occurs between DPA and HEMA under the catalysis of concentrated sulfuric acid to generate the lipid intermediate LIM. Subsequently, under the initiation of BPO, it reacts with the C=C double bond in SIS to prepare S-SIS. By constructing the dynamic covalent bond structure of SIS, a more complete cross-linked network structure is formed in the hot melt pressure-sensitive adhesive, improving the physical properties of the hot melt pressure-sensitive adhesive prepared from S-SIS. Compared with the hot melt pressure-sensitive adhesive prepared from unmodified SIS, the softening point of the modified hot melt pressure-sensitive adhesive and the peel strength after high-temperature aging have both increased to a certain extent. The dynamic covalent bond structure of SIS can improve the low-temperature performance of the hot melt pressure-sensitive adhesive. The presence of dynamic disulfide bonds enhances the low-temperature adhesion performance and crack resistance of the hot melt pressure-sensitive adhesive.

[0037] Advantages of the present invention:

[0038] By synthesizing a specific lipid intermediate and using it to modify SIS, the present invention can improve the high-temperature performance of SIS, which is beneficial to increasing the process temperature for preparing the hot melt pressure-sensitive adhesive. By constructing the dynamic covalent bond structure of SIS, a more complete cross-linked network structure is formed in the hot melt pressure-sensitive adhesive, improving the physical properties of the hot melt pressure-sensitive adhesive prepared from the modified SIS (S-SIS).

[0039] By constructing the dynamic covalent bond structure of SIS, compared with the hot melt pressure-sensitive adhesive prepared from unmodified SIS, the softening point of the modified hot melt pressure-sensitive adhesive has increased to a certain extent. At the same time, the present invention can improve the low-temperature performance of the hot melt pressure-sensitive adhesive. Due to the presence of dynamic disulfide bonds, the low-temperature performance and crack resistance of the hot melt pressure-sensitive adhesive are enhanced. Description of the drawings

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is the Raman spectrum test chart of DPA and LIM in Example 1;

[0042] Figure 2 It is the infrared spectrum test chart of SIS before and after modification in Example 1. Specific embodiments

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0044] It should be noted that the heating equipment used in the embodiments of this application can be a constant temperature oil bath, or other equipment with the same function can also be used; the drying equipment used in the embodiments of this application can be a vacuum drying oven, or other equipment with the same function can also be used. If an ordinary drying oven is used, the drying temperature should be appropriately increased.

[0045] Example 1

[0046] This embodiment provides a modified hot melt pressure-sensitive adhesive and its preparation method. The specific steps are as follows, where the amounts of materials are all in parts by weight:

[0047] 1. Weigh 20 parts of DPA and 20 parts of HEMA into a three-necked flask, add 0.8 part of concentrated sulfuric acid, and then carry out magnetic stirring reaction. The reaction temperature is 85 °C, the reaction time is 2 h, and the stirring speed is 60 r / min to obtain Solution 1.

[0048] 2. Pour the Solution 1 prepared in Step 1 into a clean beaker, seal it, and let it stand at room temperature for 24 h to obtain Solution 2.

[0049] 3. Filter the unreacted DPA from the standing Solution 2 in Step 2 to obtain a yellow viscous liquid, which is the lipid intermediate LIM.

[0050] 4. Weigh 5 parts of SIS into a three-necked flask, add 50 parts of the solvent toluene, and heat and dissolve it fully to obtain an SIS solution.

[0051] 5. Take 1 part of the LIM obtained in Step 3 and 0.2 part of benzoyl peroxide (BPO), add them to the SIS solution obtained in Step 4, heat and stir to carry out a grafting reaction. The reaction temperature is 85 °C, the reaction time is 6 h, and the stirring speed is 70 r / min. During the reaction, introduce nitrogen protection intermittently 5 times to prevent the oxidation of benzoyl peroxide and obtain a modified SIS solution.

[0052] 6. Wash the modified SIS solution prepared in Step 5 with 120 parts of anhydrous methanol until no light yellow precipitate precipitates. The filtered light yellow precipitate is dried in a vacuum drying oven at 60 °C until the mass is constant to obtain a modified SIS solid substance.

[0053] 7. Add 20 parts of plasticizer naphthenic oil, 0.5 part of antioxidant 168, and 0.5 part of ultraviolet absorber 326 into a stainless steel cylinder, mix them at 160 °C, add 25 parts of the modified SIS obtained in step 6, use a mechanical stirrer to stir at a speed of 1000 r / min for 2 h to mix evenly, then add 40 parts of tackifier hydrogenated dicyclopentadiene petroleum resin, and continue to stir at a speed of 1000 r / min for 60 min to obtain a modified hot melt pressure-sensitive adhesive.

[0054] The Raman spectra test diagrams of DPA and LIM are as Figure 1 shown, Figure 1 the small diagram in the upper left corner of Figure 1 is the partial enlarged view of the figure in the red dotted box in the lower right corner; it can be seen from Figure 1 that the characteristic peaks corresponding to the S-S bond and C-S bond in DPA are at 504 cm -1 and 662 cm -1 . In the spectrum of LIM, the characteristic peaks corresponding to the S-S bond and C-S bond are observed at 510 cm -1 and 668 cm -1 , which proves the successful preparation of LIM.

[0055] Figure 2 The infrared spectra test diagrams of SIS before and after modification with LIM are shown below. Among them, S-SIS represents the modified SIS after modifying SIS with LIM; it can be seen from Figure 2 that C=O and C-O-C absorption peaks appear at 1160 cm -1 and 1730 cm -1 for S-SIS respectively, indicating the successful construction of dynamic disulfide bonds in SIS. The absorption peak at 837 cm -1 belongs to the deformation vibration of the C-H bond connected to the C=C double bond in the polyisoprene chain. Comparing the SIS and S-SIS at 837 cm -1 , the decrease in the absorption peak intensity also indicates the successful preparation of S-SIS.

[0056] Example 2

[0057] This example provides a modified hot melt pressure-sensitive adhesive and its preparation method. The specific steps are as follows, where the dosages of the materials are all in parts by weight:

[0058] 1. Weigh 20 parts of DPA and 24 parts of HEMA into a three-necked flask, add 0.9 part of concentrated sulfuric acid, and then carry out a magnetic stirring reaction. The reaction temperature is 90 °C, the reaction time is 1.5 h, and the stirring speed is 70 r / min to obtain Solution 1;

[0059] 2. Pour the Solution 1 prepared in step 1 into a clean beaker, seal it, and let it stand at room temperature for 48 h to obtain Solution 2;

[0060] 3. Filter the unreacted DPA from the standing solution II in step 2 to obtain a yellow viscous liquid, which is the lipid intermediate LIM;

[0061] 4. Weigh 8 parts of SIS into a three-necked flask, add 65 parts of the solvent toluene, and heat to dissolve it thoroughly to obtain an SIS solution;

[0062] 5. Take 1.5 parts of the LIM obtained in step 3 and 0.25 part of benzoyl peroxide (BPO), add them to the SIS solution obtained in step 4, heat and stir for grafting reaction. The reaction temperature is 90 °C, the reaction time is 5 h, and the stirring speed is 70 r / min. During the reaction, introduce nitrogen protection intermittently for 5 times to prevent benzoyl peroxide from being oxidized, and obtain a modified SIS solution;

[0063] 6. Wash the modified SIS solution prepared in step 5 with 120 parts of anhydrous methanol until no light yellow precipitate precipitates. The filtered light yellow precipitate is dried in a vacuum drying oven at 60 °C until the mass is constant, and a modified SIS solid substance is obtained;

[0064] 7. Add 30 parts of the plasticizer naphthenic oil, 1.0 part of antioxidant 168, and 1.0 part of ultraviolet absorber 326 to a stainless steel cylinder, mix at 180 °C, add 25 parts of the modified SIS obtained in step 6, use a mechanical stirrer to stir at a speed of 2000 r / min for 1 h to mix evenly, then add 50 parts of the tackifier hydrogenated dicyclopentadiene petroleum resin, and continue to stir at a speed of 2000 r / min for 30 min to obtain a modified hot melt pressure-sensitive adhesive.

[0065] Example 3

[0066] This example provides a modified hot melt pressure-sensitive adhesive and its preparation method. The specific steps are as follows, where the amounts of materials are all in parts by weight:

[0067] 1. Weigh 20 parts of DPA and 20 parts of HEMA into a three-necked flask, add 0.95 part of concentrated sulfuric acid, and react with magnetic stirring. The reaction temperature is 95 °C, the reaction time is 1 h, and the stirring speed is 80 r / min to obtain solution I;

[0068] 2. Pour the solution I prepared in step 1 into a clean beaker, seal it, and let it stand at room temperature for 48 h to obtain solution II;

[0069] 3. Filter the unreacted DPA from the standing solution II in step 2 to obtain a yellow viscous liquid, which is the lipid intermediate LIM;

[0070] 4. Weigh 10 parts of SIS into a three-necked flask, add 75 parts of the solvent toluene, and heat to dissolve it thoroughly to obtain an SIS solution;

[0071] 5. Take 0.5 parts of LIM obtained in step 3 and 0.15 parts of benzoyl peroxide (BPO) and add them to the SIS solution obtained in step 4, heat and stir to carry out grafting reaction, the reaction temperature is 95° C., the reaction time is 2 h, the stirring speed is 60 r / min, and during the reaction, nitrogen protection is intermittently introduced 3 times to prevent benzoyl peroxide from being oxidized, to obtain a modified SIS solution;

[0072] 6. Wash the modified SIS solution obtained in step 5 with 120 parts of anhydrous methanol until no light yellow precipitate is precipitated. Dry the filtered light yellow precipitate in a vacuum drying oven at 60° C. until the mass is constant, thereby obtaining a modified SIS solid material;

[0073] 7. Add 40 parts of plasticizer cyclopentane oil, 0.7 parts of antioxidant 168 and 0.8 parts of ultraviolet absorber 326 into a stainless steel cylinder, mix at 170°C, add 25 parts of modified SIS obtained in step 6, use a mechanical stirrer to stir at 1500 r / min for 1.5 h to mix evenly, then add 60 parts of tackifier hydrogenated dicyclopentadiene petroleum resin, continue stirring at 1500 r / min for 45 min to obtain a modified hot melt pressure-sensitive adhesive.

[0074] Comparative Example 1

[0075] This comparative example provides a hot melt pressure sensitive adhesive and a preparation method thereof, and the specific steps are as follows, wherein the amounts of materials used are all measured in parts by weight:

[0076] Add 20 parts of plasticizer cyclopentane oil, 0.5 parts of antioxidant 168 and 0.5 parts of ultraviolet absorber 326 into a stainless steel cylinder, mix at 160°C, add 25 parts of SIS, use a mechanical stirrer to stir at 1000 r / min for 2 hours to mix evenly, then add 40 parts of tackifier hydrogenated dicyclopentadiene petroleum resin, continue stirring at 1000 r / min for 60 minutes to obtain a hot melt pressure-sensitive adhesive.

[0077] Comparative Example 2

[0078] This comparative example provides a modified hot melt pressure-sensitive adhesive and a preparation method thereof. The specific steps are as follows, wherein the amounts of materials are all calculated by weight:

[0079] 1. Weigh 10 parts of SIS into a three-necked flask, add 75 parts of solvent toluene, heat and fully dissolve to obtain SIS solution;

[0080] 2. Add 10 parts of hydrogen peroxide and 3 parts of formic acid, heat and stir to carry out epoxidation reaction, the reaction temperature is 60°C, the reaction time is 2h, and the stirring speed is 60r / min to obtain a modified SIS solution;

[0081] 3. Wash the modified SIS solution prepared in Step 2 with 120 parts of anhydrous methanol until no white precipitate forms. Dry the filtered white precipitate in a vacuum drying oven at 60 °C until the mass is constant to obtain the modified SIS solid substance.

[0082] 4. Add 30 parts of plasticizer naphthenic oil, 1.0 part of antioxidant 168, and 1.0 part of ultraviolet absorber 326 to a stainless-steel cylinder. Mix at 180 °C, add 25 parts of the modified SIS obtained in Step 3, and use a mechanical stirrer to stir at a speed of 2000 r / min for 1 h to mix evenly. Then add 50 parts of tackifier hydrogenated dicyclopentadiene petroleum resin and continue to stir at a speed of 2000 r / min for 30 min to obtain the modified hot-melt pressure-sensitive adhesive.

[0083] Conduct performance tests on the hot-melt pressure-sensitive adhesives prepared in the examples and comparative examples, and compare them with the reference standard data of the national standard HG / T 5913-2021. The specific results are shown in Table 1:

[0084] Table 1 Performance test results of hot-melt pressure-sensitive adhesives

[0085]

[0086] As can be seen from the test results in Table 1, the softening points of the hot melt pressure-sensitive adhesives of the modified SIS thermoplastic elastomers in the examples have all increased. Among them, the improvement effect of the softening point of the hot melt pressure-sensitive adhesive containing the modified SIS thermoplastic elastomer in Example 2 is the most obvious. Compared with Comparative Example 1 where SIS was not improved, the softening point of Example 2 increased by 7.3 °C; compared with Comparative Example 2 with conventional SIS modification in the prior art, the softening point of Example 2 increased by 5.9 °C; at 170 °C, the melt viscosities of Comparative Examples 1-2 were both 2500-3000 mPa·s, and the melt viscosities of Examples 1-3 were 3000-3500 mPa·s, indicating that the bonding strength of the SIS-based modified hot melt pressure-sensitive adhesive prepared by the method of this application is better; the hot melt pressure-sensitive adhesive of Comparative Example 1 had slippage, flowing, and dripping under the conditions of 80 °C and 2 h, while the hot melt pressure-sensitive adhesives of Examples 1-3 had no slippage, flowing, and dripping under the conditions of 80 °C and 2 h, indicating that the modified hot melt pressure-sensitive adhesive of this application has better heat resistance; no cracking occurred in the low-temperature flexibility tester at -27 °C, indicating that the hot melt pressure-sensitive adhesive has good low-temperature flexibility; the peel strengths of the hot melt pressure-sensitive adhesives of the modified SIS thermoplastic elastomers in the examples have all increased. Among them, the peel strength increase in Example 2 is the most obvious. The T-peel strength with the coil under the condition of no treatment is 2.0 N / mm, which is 1.2 N / mm higher than that of Comparative Example 1, 1.4 N / mm higher than that of Comparative Example 2, and 1.0 N / mm higher than the national standard; the T-peel strength with the coil at 35 °C is 1.2 N / mm, which is 0.8 N / mm higher than that of Comparative Example 1, 0.9 N / mm higher than that of Comparative Example 2, and 0.7 N / mm higher than the national standard; the T-peel strength with the coil at 5 °C is 1.5 N / mm, which is 1.0 N / mm higher than that of Comparative Example 1, 1.1 N / mm higher than that of Comparative Example 2, and 0.9 N / mm higher than the national standard. In summary, by constructing the SIS dynamic disulfide bond structure, the bonding strength of the hot melt pressure-sensitive adhesive prepared with the modified SIS is improved compared with that of the hot melt pressure-sensitive adhesive prepared in the comparative example, and it has better heat resistance and low-temperature performance.

[0087] Please note that the technical features of the above examples can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above examples are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as the scope described in this specification. The above examples only represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of this application, several deformations and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application should be subject to the appended claims.

Claims

1. A modified hot melt pressure-sensitive adhesive, characterized in that, By weight parts, the components of the modified hot melt pressure-sensitive adhesive include: 25-30 parts of modified SIS, 20-40 parts of plasticizer, 40-60 parts of tackifier, 0.5-1.0 part of antioxidant, 0.5-1.0 part of ultraviolet absorber, and 1-2 parts of defoamer.

2. The modified hot melt pressure-sensitive adhesive according to claim 1, characterized in that, The modified SIS is SIS with a dynamic disulfide bond structure.

3. The modified hot melt pressure-sensitive adhesive according to claim 1, characterized in that, The plasticizer includes naphthenic oil; Preferably, the tackifier includes hydrogenated dicyclopentadiene petroleum resin; Preferably, the antioxidant includes antioxidant 168 and / or antioxidant 3114; Preferably, the ultraviolet absorber includes ultraviolet absorber 326; Preferably, the defoamer includes dimethyl silicone oil.

4. A method for preparing a modified hot melt pressure-sensitive adhesive according to any one of claims 1-3, characterized in that, The preparation method includes: blending the modified SIS, the tackifier, the plasticizer, the antioxidant, the ultraviolet absorber, and the defoamer according to weight parts, heating, and stirring to obtain a hot melt pressure-sensitive adhesive.

5. The preparation method according to claim 4, characterized in that, The blending includes: adding the plasticizer, the antioxidant, and the ultraviolet absorber into a stainless-steel container, blending at 160-180 °C, then adding the modified SIS, stirring at a speed of 1000-2000 r / min for 1-2 h to blend evenly, then adding the tackifier, and continuing to stir at a speed of 1000-2000 r / min for 30-60 min.

6. The preparation method according to claim 4, characterized in that, The preparation method of the modified SIS includes the following steps: S1: Heating and stirring 3,3'-dithiodipropionic acid (DPA) and 2-hydroxyethyl methacrylate (HEMA) under the catalysis of concentrated sulfuric acid to carry out a first reaction to obtain a lipid intermediate LIM; S2: Dissolving SIS in a solvent to obtain an SIS solution; S3: Adding the lipid intermediate LIM and benzoyl peroxide (BPO) obtained in S1 into the SIS solution obtained in S2, heating and stirring to carry out a second reaction to obtain a modified SIS solution; S4: Washing the modified SIS solution obtained in S3 with a detergent, filtering the precipitate, and drying to obtain the modified SIS.

7. The preparation method according to claim 6, characterized in that Step S1 satisfies one or more of the following conditions: a. By weight parts, the 3,3'-dithiodipropionic acid (DPA) is 15-25 parts, the 2-hydroxyethyl methacrylate (HEMA) is 20-24 parts, and the concentrated sulfuric acid is 0.8-0.96 parts; b. The target temperature of the heating is 85-95 °C; c. The stirring speed is 60-80 r / min; d. The time of the first reaction is 1-2 h.

8. The preparation method according to claim 6 or 7, characterized in that, The preparation method of the modified SIS also satisfies one or more of the following conditions: e. In step S1, the first reaction further includes: after the reaction is completed, cooling the system to room temperature and standing for 24-72 h; f. In step S2, the solvent includes toluene and / or xylene; g. The system composition of the second reaction in step S3 includes: by weight parts, the SIS is 5-10 parts, the solvent is 50-75 parts, the LIM is 0.5-1.5 parts, and the BPO is 0.15-0.25 parts; h. In step S4, the detergent includes anhydrous methanol and / or anhydrous ethanol.

9. The preparation method according to claim 8, characterized in that, In the step S3, the temperature of the second reaction is 85 - 95 °C, and the reaction time is 2 - 6 h; Preferably, the stirring speed is 60 - 80 r / min.

10. The preparation method according to claim 6 or 9, characterized in that, In the step S3, during the second reaction, gas protection is intermittently introduced; Preferably, the gas is nitrogen or argon; Preferably, the number of times of intermittent introduction is 3 - 5 times.

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