Brominated SIS thermoplastic elastomer and preparation method thereof

Abstract

The invention provides a brominated SIS thermoplastic elastomer and a preparation method thereof.The preparation method comprises the steps that 1, 2, 3-dibromo-1-propylene and styrene are subjected to a block copolymerization reaction, then 4-vinyl benzoic acid is added for an acidification reaction, and a ring opening agent is obtained; step 2, carrying out epoxidation reaction on a polyisoprene chain segment in the SIS thermoplastic elastomer to obtain epoxidized SIS; step 3, carrying out ring-opening reaction on a ring-opening agent and the epoxidized SIS to obtain a brominated SIS thermoplastic elastomer; wherein the mass ratio of the 2, 3-dibromo-1-propylene to the styrene to the 4-vinyl benzoic acid is (85.0 to 90.0): (10.0 to 15.0): (3.0 to 5.0); the molar ratio of the ring-opening agent to the epoxy group in the epoxidized SIS is greater than or equal to 1. Compared with an SIS thermoplastic elastomer, the brominated SIS thermoplastic elastomer obtained by the method disclosed by the invention not only has certain polarity, and the compatibility of the brominated SIS thermoplastic elastomer with other polar resins is improved, so that the peel strength of a subsequently prepared pressure-sensitive adhesive is improved, but also has enough raw rubber tensile strength.

Description

Technical Field

[0001] This invention belongs to the field of styrene-based thermoplastic elastomers, specifically relating to a brominated SIS thermoplastic elastomer and its preparation method. Background Technology

[0002] SIS is a styrene-based thermoplastic elastomer composed of a styrene-isoprene-styrene triblock copolymer, with polyisoprene as the middle block. Its structure contains a methyl side chain, resulting in excellent cohesive strength and superior adhesion properties. Its microstructure determines its outstanding advantages in adhesive applications, making it a major base material for hot melt pressure-sensitive adhesives and widely used in packaging, labeling, and biomedicine. With the rapid development of new energy, electronics, and precision instruments, the annual growth rate of hot melt pressure-sensitive adhesives exceeds 13%, making the high-performance development of hot melt pressure-sensitive adhesives a current research hotspot.

[0003] However, as a non-polar polymer, SIS thermoplastic elastomers inevitably suffer from poor compatibility with polar materials, resulting in poor adhesion, poor oil resistance, and insufficient tack. Consequently, the performance of SIS thermoplastic elastomers cannot meet the increasingly diverse application scenarios, becoming a bottleneck for expanding the application of SIS thermoplastic elastomer materials.

[0004] Polarization refers to enhancing the polarity of materials by introducing polar groups, polar side chains, or blending with polar substances, thereby improving their adhesion and oil resistance. Polarization can further broaden the application fields of SIS thermoplastic elastomers. Therefore, polarization modification of SIS thermoplastic elastomers has become the most effective method to solve the above problems. Polarization mainly includes the introduction of polar monomers through polymerization and post-functionalization polarization modification. The method of introducing polar monomers through polymerization (mainly by living anionic polymerization) is difficult to implement and has a narrow range of polar monomers that can be selected. The post-functionalization modification method mainly utilizes the unsaturated double bonds of isoprene segments in the SIS polymer molecular chain to introduce polar groups or segments. The modified products have a clear structure, relatively stable chemical properties, simple composition, and high polarization efficiency, making them relatively easy to implement and becoming one of the hot research directions in the polarization of SIS thermoplastic elastomers.

[0005] CN116515138A discloses a dynamic crosslinking network of spiropyran-modified SIS with mechanochromic properties. The dynamic crosslinking network SIS-SP-UPy, with spiropyran-modified SIS as the main chain, is constructed by epoxy functionalizing the double bonds of the polyisoprene (PI) blocks in the SIS (ESIS-hydroxy-functionalized SIS-OH), and using the esterification reaction of isocyanate NCO and OH. Bis-terminated NCO-functionalized spiropyran SP is used as the covalent crosslinking agent SP-NCO, and NCO-functionalized 2-ureido-4[1H]-pyrimidinone is used as the dynamic hydrogen-bonding crosslinking agent UPy-NCO. SP-NCO and UPy-NCO are then grafted onto the side chains of SIS-OH, resulting in a dynamic crosslinking network SIS-SP-UPy with both covalent and dynamic hydrogen-bonding crosslinking. This modified SIS primarily focuses on color-changing properties.

[0006] Therefore, how to improve the polarity of SIS thermoplastic elastomers to give them better application performance is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The main objective of this invention is to provide a brominated SIS thermoplastic elastomer and its preparation method, thereby addressing the non-polarity issue of SIS thermoplastic elastomers, improving their compatibility with other resins, and ultimately enhancing the bonding strength of the pressure-sensitive adhesives prepared subsequently. The brominated SIS thermoplastic elastomer of this invention also possesses sufficient raw rubber tensile strength to meet the requirements of pressure-sensitive adhesives in new energy, high-end electronics, and biomedical industries.

[0008] To achieve the above objectives, the present invention provides a method for preparing brominated SIS thermoplastic elastomer, comprising the following steps:

[0009] Step 1 involves a block copolymerization reaction of 2,3-dibromo-1-propene and styrene, followed by the addition of 4-vinylbenzoic acid for an acidification reaction to obtain a ring-opening agent.

[0010] Step 2: The polyisoprene segments in the SIS thermoplastic elastomer undergo an epoxidation reaction to obtain epoxidized SIS;

[0011] Step 3: The ring-opening agent is reacted with the epoxidized SIS to obtain the brominated SIS thermoplastic elastomer;

[0012] The mass ratio of 2,3-dibromo-1-propene, styrene, and 4-vinylbenzoic acid is (85.0–90.0):(10.0–15.0):(3.0–5.0); the molar ratio of the ring-opening agent to the epoxy group in the epoxidized SIS is greater than or equal to 1.

[0013] The method for preparing brominated SIS thermoplastic elastomer according to the present invention, wherein step 1 is as follows: 2,3-dibromo-1-propylene is subjected to a polymerization reaction, and after the conversion rate of 2,3-dibromo-1-propylene monomer reaches 95%-100%, styrene is added to carry out a polymerization reaction, and after the conversion rate of styrene monomer reaches 95%, 4-vinylbenzoic acid is added to carry out an acidification reaction to obtain a ring-opening agent.

[0014] The method for preparing brominated SIS thermoplastic elastomer of the present invention, wherein the polymerization reaction of 2,3-dibromo-1-propylene is carried out in a first solvent under the action of an initiator and a structure modifier; the initiator is a hydrocarbon monolithium compound, the structure modifier is a polar organic compound, and the first solvent is a hydrocarbon solvent; the mass ratio of 2,3-dibromo-1-propylene, styrene and 4-vinylbenzoic acid is (85.0-90.0):(10.0-15.0):(3.0-5.0); and the molar ratio of the structure modifier to the initiator is (1.0-2.0):1.

[0015] The method for preparing brominated SIS thermoplastic elastomer according to the present invention includes a block copolymerization reaction at a temperature of 55-65°C, an acidification reaction at a temperature of 55-65°C, and an acidification reaction time of 30-50 min.

[0016] The method for preparing brominated SIS thermoplastic elastomer according to the present invention, wherein the ring-opening agent has the following structure:

[0017]

[0018] Where PS represents a styrene homopolymer block; n is the number of repeating units, n≥1.

[0019] The method for preparing brominated SIS thermoplastic elastomer according to the present invention, wherein the ring-opening agent has a number-average molecular weight of 4000-5000 and a molecular weight distribution of 1.76-2.41.

[0020] The method for preparing brominated SIS thermoplastic elastomer according to the present invention, wherein the epoxidation reaction of the polyisoprene segments in the SIS thermoplastic elastomer is carried out in a second solvent under the action of organic acid and peroxide.

[0021] The method for preparing brominated SIS thermoplastic elastomer according to the present invention includes the following: the organic acid is selected from at least one of formic acid, acetic acid, benzoic acid and salicylic acid, and the molar ratio of the organic acid to the SIS thermoplastic elastomer is (0.05-1.0):1; the peroxide is hydrogen peroxide and / or peracetic acid, and the molar ratio of the peroxide to the SIS thermoplastic elastomer is (0.1-1.5):1; the second solvent is selected from at least one of chlorobenzene, benzene, toluene, xylene, chloroform, acetone and ethylbenzene.

[0022] The method for preparing brominated SIS thermoplastic elastomer according to the present invention, wherein the epoxy degree of the epoxidized SIS is 7%-12%.

[0023] The method for preparing brominated SIS thermoplastic elastomer according to the present invention includes a ring-opening reaction between the ring-opening agent and the epoxidized SIS carried out under the action of a ring-opening catalyst, wherein the ring-opening catalyst is selected from at least one of zirconium tetrachloride, trifluoromethanesulfonic acid and imidazole; the molar ratio of the ring-opening catalyst to the epoxy groups in the epoxidized SIS is (0.02-0.5):1; and the molar ratio of the ring-opening agent to the epoxy groups in the epoxidized SIS is (1.2-2.0):1.

[0024] The method for preparing brominated SIS thermoplastic elastomer of the present invention includes the following steps: before mixing the epoxidized SIS with the ring-opening agent, the epoxidized SIS is first mixed with an organic solvent, and the pH of the mixture is adjusted to 1-5; the molar ratio of epoxy groups, ring-opening agent and ring-opening catalyst in the epoxidized SIS is 100:(120-200):(4-12).

[0025] The method for preparing brominated SIS thermoplastic elastomer of the present invention includes adjusting the pH of the mixture to 1-5 using an acid anhydride, wherein the acid anhydride is selected from one or more of propionic anhydride, butyric anhydride, valeric anhydride, hexanoic anhydride, and octanoic anhydride.

[0026] The method for preparing brominated SIS thermoplastic elastomer according to the present invention, wherein the ring-opening reaction temperature is 130-140°C and the ring-opening reaction time is 3.0-4.0 hr.

[0027] To achieve the above objectives, the present invention also provides brominated SIS thermoplastic elastomers obtained by the above preparation method.

[0028] The beneficial effects of this invention are:

[0029] (1) This invention uses styrene and 2,3-dibromo-1-propene as reactants and synthesizes a macromolecular brominated ring-opening agent by end-acidification with 4-vinylbenzoic acid. This macromolecular brominated ring-opening agent mainly plays three roles: Firstly, it combines bromomethyl and bromine atoms onto a single macromolecular chain. The "superposition effect" of the bromomethyl and bromine atoms has a significant synergistic effect in improving the polarity of SIS thermoplastic elastomers, greatly enhancing the polarity of SIS thermoplastic elastomers, improving compatibility with polar materials, and exhibiting good adhesion. Secondly, through the ring-opening reaction of 4-vinylbenzoic acid with epoxy groups, the macromolecular segment of alkyl bromine in the macromolecular brominated ring-opening agent is attached to the isoprene segment of the SIS thermoplastic elastomer, rather than through traditional bromine atom substitution. This avoids the formation of HBr, reduces bromine loss, and improves the utilization rate of bromine in the macromolecular brominated ring-opening agent. This demonstrates that the macromolecular brominated ring-opening agent can significantly improve the polarity of SIS thermoplastic elastomers even with a relatively low addition amount. Thirdly, it helps prevent the reduction of tensile strength in brominated SIS thermoplastic elastomer raw rubber. The -PS- homopolymer segments in the macromolecular brominated ring-opening agent contain a large number of benzene rings. Benzene rings have the characteristics of high rigidity and large steric hindrance, which can avoid the problem of the molecular weight distribution of SIS thermoplastic elastomer becoming wider due to branching, thereby leading to a decrease in the tensile strength of SIS thermoplastic elastomer raw rubber.

[0030] Therefore, the macromolecular brominated ring-opening agent designed in this invention organically combines the properties of bromomethyl, bromine atoms and -PS- and works synergistically. It not only effectively solves the non-polarity problem of SIS thermoplastic elastomer and improves its compatibility with other resins, but also greatly improves the bonding strength of the pressure-sensitive adhesive prepared subsequently. In addition, it maintains sufficient raw rubber tensile strength of SIS thermoplastic elastomer.

[0031] (2) In the preparation process of brominated SIS thermoplastic elastomer, this invention eliminates the emission of volatile organic compounds (VOCs) and byproduct HBr, avoiding harm to humans and the environment. It also eliminates the need for alkaline washing and recovery of the byproduct HBr, thereby shortening the process and reducing production costs. The preparation method of this invention is green and environmentally friendly, with controllable bromine structure, low addition amount, significant modification effect, and low modification cost, making it suitable for industrial production. Detailed Implementation

[0032] The technical solution of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. Structures or experimental methods not specified in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, "parts" in the present invention refer to parts by mass, and "ratio" refers to mass ratio.

[0033] This invention first synthesizes a macromolecular brominated ring-opening agent using 4-vinylbenzoic acid, styrene, and 2,3-dibromo-1-propene; secondly, it performs an epoxidation reaction on the PI (polyisoprene) segments containing double bonds in the SIS thermoplastic elastomer to obtain epoxidized SIS; finally, it performs a ring-opening reaction between the macromolecular brominated ring-opening agent and the epoxidized SIS to prepare the brominated SIS thermoplastic elastomer.

[0034] In one embodiment, the method for preparing the brominated SIS thermoplastic elastomer of the present invention includes the following steps:

[0035] Step 1 involves a block copolymerization reaction of 2,3-dibromo-1-propene and styrene, followed by the addition of 4-vinylbenzoic acid for an acidification reaction to obtain a ring-opening agent.

[0036] Step 2: The polyisoprene segments in the SIS thermoplastic elastomer undergo an epoxidation reaction to obtain epoxidized SIS;

[0037] Step 3: The ring-opening agent is reacted with the epoxidized SIS to obtain the brominated SIS thermoplastic elastomer;

[0038] The mass ratio of 2,3-dibromo-1-propene, styrene, and 4-vinylbenzoic acid is (85.0–90.0):(10.0–15.0):(3.0–5.0).

[0039] The SIS thermoplastic elastomer of this invention improves the non-polarity problem, has good compatibility with other resins, and the pressure-sensitive adhesive prepared from it has high bonding strength. Moreover, the SIS thermoplastic elastomer of this invention has good raw rubber tensile strength, which can meet the requirements of pressure-sensitive adhesives in new energy, high-end electronics industry and biomedicine.

[0040] In one embodiment, step 1 is: to polymerize 2,3-dibromo-1-propylene, then add styrene to polymerize, and then add 4-vinylbenzoic acid to acidify, thereby obtaining a ring-opening agent.

[0041] Step 1 of this invention is carried out in an inert gas atmosphere. This invention does not impose any particular limitation on the inert gas, as long as it does not affect the reaction, such as nitrogen or argon. In another embodiment, after the conversion rate of 2,3-dibromo-1-propene monomer reaches 95%-100%, styrene is added. After the styrene monomer conversion rate reaches over 95%, 4-vinylbenzoic acid is added for an acidification reaction. After the reaction, the slurry is poured out, coagulated, washed, and vacuum dried to obtain a macromolecular polar brominated ring-opening agent.

[0042] In yet another embodiment, the polymerization of 2,3-dibromo-1-propylene is carried out in a first solvent in the presence of an initiator and a structure modifier.

[0043] The initiator can be a hydrocarbon monolithium compound, such as R′Li, where R′ is a saturated aliphatic hydrocarbon group containing 1-20 carbon atoms, an alicyclic hydrocarbon group containing 2-20 carbon atoms, an aromatic hydrocarbon group having 6-20 carbon atoms, or a complex group of the above groups. In one embodiment, the hydrocarbon monolithium compound is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthenelithium, cyclohexyllithium, and dodecyllithium, preferably n-butyllithium. The present invention does not particularly limit the amount of initiator added. In one embodiment, it is determined by the molecular weight of the polar brominated ring-opening agent of the target product macromolecule, for example, by calculating the amount of hydrocarbon monolithium compound using the following formula:

[0044] The molar mass (mol) of a hydrocarbon-based monolithium compound = total mass of the gel m (g) / molecular weight M (g / mol)

[0045] The total mass of the gel refers to the total mass of the reactants 2,3-dibromo-1-propene and styrene, and the molecular weight refers to the molecular weight of the target product, a large polar brominated ring-opening agent.

[0046] The structure modifier is a polar organic compound capable of producing a solvation effect in the polymerization system. In one embodiment, the polar organic compound is selected from diethylene glycol dimethyl ether (DGE), tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether (DME), and triethylamine, preferably tetrahydrofuran (THF).

[0047] The first solvent is a hydrocarbon solvent, which can be a straight-chain alkane, aromatic hydrocarbon, or cycloalkanes, such as one selected from pentane, hexane, octane, heptane, and cyclohexane, with cyclohexane being preferred.

[0048] In one embodiment, the mass ratio of the first solvent, 2,3-dibromo-1-propene, styrene, and 4-vinylbenzoic acid is (400-500):(85.0-90.0):(10.0-15.0):(3.0-5.0); and the molar ratio of the structure modifier to the initiator is (1.2-2.0):1.

[0049] In one embodiment, the block copolymerization reaction is carried out at a temperature of 55–65°C, the acidification reaction is carried out at a temperature of 55–65°C, and the acidification reaction takes 30–50 minutes. In another embodiment, the reaction is carried out under stirring at a speed of 500–600 rpm.

[0050] In one specific embodiment, step 1 is as follows: In an inert gas purging process, a jacketed stainless steel reactor is introduced into the reactor. The first solvent, 2,3-dibromo-1-propene, and a structure modifier are added sequentially to the polymerization reactor. The reactor is stirred and heated. Then, an initiator is added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reaches 100%, styrene is added to the polymerization reactor to react. When the conversion rate of styrene monomer reaches 97%, 4-vinylbenzoic acid is added to the polymerization reactor for single-end sealing. After the reaction, the slurry is poured out, coagulated, washed, and vacuum dried to obtain a macromolecular polar brominated ring-opening agent.

[0051] In one embodiment, the ring-opening agent of the present invention has the following structure:

[0052]

[0053] Where PS represents a styrene homopolymer block; n is the number of repeating units, n≥1, and in another embodiment, n≤50.

[0054] In another embodiment, the ring-opening agent has a number-average molecular weight (Mn) of 4000 to 5000 and a molecular weight distribution (Mw / Mn) of 1.76 to 2.41.

[0055] Step 2 involves epoxidizing the polyisoprene segments in the SIS thermoplastic elastomer to obtain epoxidized SIS.

[0056] The present invention does not particularly limit the SIS thermoplastic elastomer. In one embodiment, the number average molecular weight (Mn) of the SIS thermoplastic elastomer is 130,000 to 200,000.

[0057] This invention does not specifically limit the method for epoxidation of polyisoprene segments in SIS thermoplastic elastomers; conventional methods in the art are acceptable. In one embodiment, the epoxidation reaction of polyisoprene segments in SIS thermoplastic elastomers is carried out in a second solvent under the action of an organic acid and a peroxide. The organic acid may be selected from at least one of formic acid, acetic acid, benzoic acid, and salicylic acid, and the molar ratio of the organic acid to the SIS thermoplastic elastomer is (0.05–1.0):1, preferably (0.08–0.25):1; the peroxide may be hydrogen peroxide and / or peracetic acid, and the molar ratio of the peroxide to the SIS thermoplastic elastomer is (0.1–1.5):1, preferably (0.4–0.6):1; the second solvent may be selected from at least one of chlorobenzene, benzene, toluene, xylene, chloroform, acetone, and ethylbenzene. The molar ratio of the SIS thermoplastic elastomer, organic acid, and peroxide is 100:(8–25):(40–60).

[0058] In one embodiment, the SIS thermoplastic elastomer is mixed with a second solvent to form a SIS thermoplastic elastomer solution, which is then added to a reaction vessel. Organic acid and peroxide are then added sequentially to the solution to carry out an epoxidation reaction. The resulting product is precipitated with ethanol, washed, and dried to obtain an epoxidized SIS thermoplastic elastomer.

[0059] In another embodiment, the mass concentration of the SIS thermoplastic elastomer in the SIS thermoplastic elastomer solution is 1 wt% to 15 wt%, preferably 5 wt% to 10 wt%.

[0060] In one embodiment, the epoxidation reaction temperature is 60–70°C, and the epoxidation reaction time is 3.0–5.0 hours. In another embodiment, the epoxy degree of the epoxidized SIS is 7%–12%. This invention grafts the homopolymer segments of the ring-opening agent onto the PI (isoprene homopolymer) segments of the SIS thermoplastic elastomer through a ring-opening reaction of carboxyl and epoxy groups. During the reaction, if the epoxy degree of the epoxidized SIS thermoplastic elastomer is too high, it easily leads to extensive entanglement of the branches, causing gelation and impairing the ductility of the SIS; if the epoxy degree is too low, the reaction introduces fewer bromine-containing branches, resulting in an insignificant modification effect. Therefore, the epoxy degree of the epoxidized SIS thermoplastic elastomer of this invention is 7%–12%.

[0061] The degree of epoxidation in epoxidized SIS is also called epoxy degree. Epoxy degree refers to the extent to which unsaturated double bonds in SIS are epoxidized; in other words, it is the percentage of epoxy groups in epoxidized SIS compared to the number of unsaturated double bonds in the unepoxidized SIS. Epoxy degree is an important indicator of the degree of epoxidation in epoxidized SIS, and it is usually measured accurately using NMR.

[0062] This invention, through precise control of the molecular weight of the macromolecular brominated ring-opening agent and the epoxy degree of the epoxidized SIS thermoplastic elastomer, avoids the gelation phenomenon easily caused by the large-scale entanglement of the branch chains, thus preventing the damage to the extensibility of the SIS thermoplastic elastomer.

[0063] Step 3 involves reacting the ring-opening agent with the epoxidized SIS to obtain a low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer.

[0064] In one embodiment, the ring-opening reaction between the ring-opening agent and the epoxidized SIS is carried out in the presence of a ring-opening catalyst. The ring-opening catalyst is selected from at least one of zirconium tetrachloride (ZrCl4), trifluoromethanesulfonic acid, and imidazole, preferably zirconium tetrachloride (ZrCl4). The molar ratio of the ring-opening catalyst to the epoxy groups in the epoxidized SIS is (0.02–0.5):1, preferably (0.04–0.12):1. To ensure that the ring-opening agent can be fully grafted onto the thermoplastic elasticity of the SIS, the molar number of carboxyl groups in the ring-opening agent needs to be greater than the molar number of epoxy groups in the epoxidized SIS. Therefore, the molar ratio of the ring-opening agent to the epoxy groups in the epoxidized SIS is greater than or equal to 1, preferably (1.2–2.0):1.

[0065] In one embodiment, epoxidized SIS is mixed with an organic solvent to prepare an epoxidized SIS thermoplastic elastomer solution, which is then added to a reaction vessel. The pH of the mixture is adjusted to 1-5, a ring-opening agent and a ring-opening catalyst are added, and the mixture is heated to carry out a ring-opening reaction. The resulting mixture is precipitated with ethanol, washed, and dried to obtain a low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer. The precipitation, washing, and drying processes are well known to those skilled in the art and can be reasonably set according to the conditions in the brominated SIS thermoplastic elastomer preparation process; this invention does not impose any particular limitations.

[0066] In one embodiment, the mass concentration of the epoxy SIS thermoplastic elastomer in the epoxidized SIS thermoplastic elastomer solution is 1.0 wt% to 10.0 wt%, preferably 3.0 wt% to 5.0 wt%. The organic solvent may be selected from at least one of chlorobenzene, benzene, toluene, xylene, chloroform, acetone, and ethylbenzene. The molar ratio of epoxy groups, ring-opening agents, and ring-opening catalysts in the epoxidized SIS is 100:(120-200):(4-12). In another embodiment, an acid anhydride is used to adjust the pH of the mixture, and the acid anhydride is selected from one or more of propionic anhydride, butyric anhydride, valeric anhydride, hexanoic anhydride, heptanoic anhydride, or octanoic anhydride.

[0067] In another embodiment, the ring-opening reaction temperature is 130–140°C, and the ring-opening reaction time is 3.0–4.0 hr.

[0068] The preparation process of the low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer of this invention is carried out in an oxygen-free, anhydrous, and inert gas environment. The inert gas can be nitrogen or a gas of an element in Group 0 of the periodic table except radon, preferably argon. The reaction apparatus can be purged before the reaction, for example, 3 to 5 times. The reaction apparatus of this invention can be a reaction vessel, such as a loop reactor or a batch reactor, preferably a batch reactor.

[0069] The present invention also provides a brominated SIS thermoplastic elastomer obtained by the above preparation method. Compared with SIS thermoplastic elastomer, it not only has a certain polarity, which improves its compatibility with other polar resins and greatly improves the peel strength of the pressure-sensitive adhesive prepared thereafter, but also maintains sufficient raw rubber tensile strength of SIS thermoplastic elastomer.

[0070] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0071] (1) Source of raw materials:

[0072] SIS thermoplastic elastomers, China Petroleum & Chemical Research Institute

[0073] Styrene, polymer grade, China National Petroleum Corporation Lanzhou Petrochemical Company

[0074] 2,3-Dibromo-1-propylene, Polymer Grade, Shanghai Kaisai Chemical Co., Ltd.

[0075] 4-Vinylbenzoic acid, 98% purity, Condis Chemical (Hubei) Co., Ltd.

[0076] Zirconium chloride (ZrCl4), 99% purity, Wuxi Yaodexin Chemical Products Co., Ltd.

[0077] n-Butyllithium, 98% purity, Nanjing Tonglian Chemical Co., Ltd.

[0078] All other reagents are commercially available industrial products.

[0079] (2) Analysis and testing methods:

[0080] Molecular weight and molecular weight distribution were determined using a Waters 2414 gel permeation chromatography (GPC) system. A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection volume was 50 μL, the elution time was 40 min, and the flow rate was 1 mL / min. -1 .

[0081] Determination of epoxy content: The preparation of epoxidized SIS was determined by using a Shimadzu UNITY 300 1H NMR spectrometer. The epoxidized SIS was dissolved in deuterated chloroform to prepare a 1% (w / w) solution for determination.

[0082] Formula for calculating epoxy degree in epoxidized SIS (ESIS):

[0083]

[0084] Among them, A 2.70 A is the integrated area of ​​the epoxy group peak in ESIS. 5.12Let be the integral area of ​​the unsaturated double bond C=C in ESIS.

[0085] Peel strength test: Determined according to the method in standard GB / T 2792-2014.

[0086] Water contact angle test: determined according to the method in standard GB / T 19466.1-2017.

[0087] Elongation: Determined according to the method in standard GB / T528-2009.

[0088] Tensile strength: determined according to the method in standard GB / T528-2009.

[0089] Example 1

[0090] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2000g of cyclohexane, 425g of 2,3-dibromo-1-propene and 152mmol of THF were added to the polymerization reactor in sequence. The stirring speed was 500rpm. When the temperature was raised to 55℃, 127mmol of n-butyllithium was added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reached 100%, 75g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 97%, 15g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 30min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 4100, Mw / Mn is 1.76).

[0091] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a 5.0 wt% SIS thermoplastic elastomer solution, which was then added to a reaction vessel. 0.08 mol of formic acid and 0.4 mol of hydrogen peroxide were then added sequentially, and the mixture was heated to 60 °C for 3.0 h for epoxidation. The resulting product was precipitated with ethanol, washed, and dried to obtain epoxidized SIS thermoplastic elastomer (epoxide content of 7.0%).

[0092] (III) Preparation of brominated SIS thermoplastic elastomer: Epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 3.0 wt% epoxidized SIS thermoplastic elastomer solution. This solution was added to a reaction vessel, and the pH of the solution was adjusted to 1.0 with propionic anhydride. Then, 1.2 mol of a macromolecular brominated ring-opening agent and 0.04 mol of ZrCl4 were added. The mixture was heated to 130℃ for 3.0 hours for ring-opening reaction. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0093] Example 2

[0094] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2100g of cyclohexane, 430g of 2,3-dibromo-1-propene and 169mmol of THF were added to the polymerization reactor in sequence. The stirring speed was 520rpm. When the temperature was raised to 57℃, 122mmol of n-butyllithium was added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reached 100%, 70g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 97%, 18g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 34min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 4300, Mw / Mn is 1.89).

[0095] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a 6.0 wt% SIS thermoplastic elastomer solution, which was then added to a reaction vessel. 0.12 mol of formic acid and 0.45 mol of hydrogen peroxide were then added sequentially, and the mixture was heated to 62 °C for 3.5 hours for epoxidation. The resulting product was precipitated with ethanol, washed, and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree of 8.3%).

[0096] (III) Preparation of Brominated SIS Thermoplastic Elastomer: 1 mol of epoxidized SIS thermoplastic elastomer containing epoxy groups was dissolved in xylene to prepare a 3.5 wt% epoxidized SIS thermoplastic elastomer solution. This solution was added to a reaction vessel, and the pH of the solution was adjusted to 2.0 with propionic anhydride. Then, 1.4 mol of a macromolecular brominated ring-opening agent and 0.06 mol of ZrCl4 were added. The mixture was heated to 132℃ for 3.5 hours for ring-opening reaction. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0097] Example 3

[0098] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2200g of cyclohexane, 435g of 2,3-dibromo-1-propene and 176mmol of THF were added to the polymerization reactor in sequence. The stirring speed was 540rpm. When the temperature was raised to 59℃, 117mmol of n-butyllithium was added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reached 100%, 65g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 97%, 20g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 38min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 4500, Mw / Mn is 1.96).

[0099] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a 7.0 wt% SIS thermoplastic elastomer solution, which was then added to a reaction vessel. 0.17 mol of formic acid and 0.51 mol of hydrogen peroxide were then added sequentially, and the mixture was heated to 65 °C for 4.0 h for epoxidation. The resulting product was precipitated with ethanol, washed, and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree of 9.8%).

[0100] (III) Preparation of Brominated SIS Thermoplastic Elastomer: 1 mol of epoxy SIS thermoplastic elastomer containing epoxy groups was dissolved in xylene to prepare a 4.0 wt% epoxy SIS thermoplastic elastomer solution. This solution was added to a reaction vessel, and the pH of the solution was adjusted to 3.0 with propionic anhydride. Then, 1.6 mol of a macromolecular brominated ring-opening agent and 0.07 mol of ZrCl4 were added. The mixture was heated to 135℃ for 3.6 hours for ring-opening reaction. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0101] Example 4

[0102] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2300g of cyclohexane, 440g of 2,3-dibromo-1-propene and 185mmol of THF were added to the polymerization reactor in sequence. The stirring speed was 560rpm. When the temperature was raised to 61℃, 112mmol of n-butyllithium was added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reached 100%, 60g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 97%, 22g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 42min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 4600, Mw / Mn is 2.16).

[0103] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare an 8.0 wt% SIS thermoplastic elastomer solution, which was then added to a reaction vessel. 0.21 mol of formic acid and 0.54 mol of hydrogen peroxide were then added sequentially, and the mixture was heated to 67 °C for 4.3 hours for epoxidation. The resulting product was precipitated with ethanol, washed, and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree of 10.6%).

[0104] (III) Preparation of brominated SIS thermoplastic elastomer: Epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 4.3 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to a reaction vessel. The pH of the solution was adjusted to 3.5 with propionic anhydride. 1.8 mol of macromolecular brominated ring-opening agent and 0.09 mol of ZrCl4 were added, and the mixture was heated to 137℃ for a ring-opening reaction for 3.7 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain brominated SIS thermoplastic elastomer. Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0105] Example 5

[0106] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2400g of cyclohexane, 445g of 2,3-dibromo-1-propene and 192mmol of THF were added to the polymerization reactor in sequence. The stirring speed was 580rpm. When the temperature was raised to 63℃, 107mmol of n-butyllithium was added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reached 100%, 55g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 97%, 23g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 46min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 4800, Mw / Mn is 2.28).

[0107] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a 9.0 wt% SIS thermoplastic elastomer solution, which was then added to a reaction vessel. 0.23 mol of formic acid and 0.58 mol of hydrogen peroxide were then added sequentially, and the mixture was heated to 68 °C for 4.6 hours for epoxidation. The resulting product was precipitated with ethanol, washed, and dried to obtain epoxidized SIS thermoplastic elastomer (epoxide content of 11.2%).

[0108] (III) Preparation of brominated SIS thermoplastic elastomer: Epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 4.6 wt% epoxidized SIS thermoplastic elastomer solution. This solution was added to a reaction vessel, and the pH of the solution was adjusted to 4.3 with propionic anhydride. Then, 1.9 mol of a macromolecular brominated ring-opening agent and 0.11 mol of ZrCl4 were added. The mixture was heated to 139 °C and subjected to a ring-opening reaction for 3.9 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0109] Example 6

[0110] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2500g of cyclohexane, 450g of 2,3-dibromo-1-propene and 2.4mmol of THF were added to the polymerization reactor in sequence. The stirring speed was 600rpm. When the temperature was raised to 65℃, 102mmol of n-butyllithium was added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reached 100%, 50g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 97%, 25g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 50min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 5000, Mw / Mn is 2.41).

[0111] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a 10.0 wt% SIS thermoplastic elastomer solution, which was then added to a reaction vessel. 0.25 mol of formic acid and 0.60 mol of peracetic acid were then added sequentially, and the mixture was heated to 70 °C for 5.0 h for epoxidation. The resulting product was precipitated with ethanol, washed, and dried to obtain epoxidized SIS thermoplastic elastomer (epoxide content of 12.0%).

[0112] (III) Preparation of Brominated SIS Thermoplastic Elastomer: 1 mol of epoxidized SIS thermoplastic elastomer containing epoxy groups was dissolved in xylene to prepare a 5.0 wt% epoxidized SIS thermoplastic elastomer solution. This solution was added to a reaction vessel, and the pH of the solution was adjusted to 5.0 with butyric anhydride. Then, 2.0 mol of a macromolecular brominated ring-opening agent and 0.12 mol of ZrCl4 were added. The mixture was heated to 140℃ for 4.0 hours to carry out the ring-opening reaction. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0113] Example 7

[0114] (I) Preparation of macromolecular brominated ring-opening agent: In a 4L stainless steel reactor with a jacket, an inert gas was introduced for purging. 2400g of cyclohexane, 448g of 2,3-dibromo-1-propene and 192mmol of THF were added sequentially to the polymerization reactor. The stirring speed was 580rpm. When the temperature was raised to 63℃, 110mmol of n-butyllithium was added to carry out the reaction. When the conversion rate of 2,3-dibromo-1-propene monomer reached 99.3%, 52g of styrene was added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reached 98.1%, 22g of 4-vinylbenzoic acid was added to the polymerization reactor for acidification reaction for 46min. After the reaction, the slurry was poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent (Mn is 4760, Mw / Mn is 2.26).

[0115] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 5.

[0116] (III) Preparation of Brominated SIS Thermoplastic Elastomer: 1 mol of epoxidized SIS thermoplastic elastomer containing epoxy groups was dissolved in xylene to prepare a 4.8 wt% epoxidized SIS thermoplastic elastomer solution. This solution was added to a reaction vessel, and the pH of the solution was adjusted to 4.4 with propionic anhydride. Then, 1.9 mol of a macromolecular brominated ring-opening agent and 0.11 mol of ZrCl4 were added. The mixture was heated to 139 °C and subjected to a ring-opening reaction for 3.9 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0117] Comparative Example 1

[0118] (I) Preparation of macromolecular brominated ring-opening agent: Other conditions are the same as in Example 2, except that the amount of 4-vinylbenzoic acid added in the preparation of the macromolecular brominated ring-opening agent is 10.0 g. That is: in a 4L stainless steel reactor with a jacket, an inert gas is introduced for purging, and 2100 g of cyclohexane, 430 g of 2,3-dibromo-1-propene and 169 mmol of THF are added to the polymerization reactor in sequence. The stirring speed is 520 rpm, and when the temperature is raised to 57°C, 122 mmol of n-butyllithium is added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reaches 100%, 70 g of styrene is added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reaches 97%, 10 g of styrene is added to the polymerization reactor. 4-Vinylbenzoic acid was subjected to an acidification reaction for 34 min. After the reaction, the slurry was poured out, coagulated, washed, and vacuum dried to obtain a macromolecular brominated ring-opening agent b (Mn is 4300, Mw / Mn is 1.86).

[0119] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 2.

[0120] (III) Preparation of Brominated SIS Thermoplastic Elastomer: Other conditions were the same as in Example 2, except that a macromolecular brominated ring-opening agent was not added during the preparation of the brominated SIS thermoplastic elastomer. Instead, a macromolecular brominated ring-opening agent b was added in an amount of 1.4 mol. Specifically, an epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 3.5 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to a reaction vessel. The pH of the solution was adjusted to 2.0 with propionic anhydride. 1.4 mol of macromolecular brominated ring-opening agent b and 0.06 mol of ZrCl4 were added, and the mixture was heated to 132°C for a ring-opening reaction for 3.5 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0121] Comparative Example 2

[0122] (I) Preparation of macromolecular brominated ring-opening agent: Other conditions are the same as in Example 3, except that 2,3-dibromo-1-propene is not added in the preparation of the macromolecular brominated ring-opening agent, but 1,1-dibromoethylene is added in an amount of 435g. That is, in a 4L stainless steel reactor with a jacket, an inert gas is introduced for purging, and 2200g of cyclohexane, 435g of 1,1-dibromoethylene and 176mmol of THF are added to the polymerization reactor in sequence. The stirring speed is 540rpm, and when the temperature is raised to 59°C, 117mmol of n-butyllithium is added to react. When the conversion rate of 1,1-dibromoethylene monomer reaches 100%, 65g of styrene is added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reaches 97%, 20g of styrene is added to the polymerization reactor. 4-Vinylbenzoic acid was subjected to an acidification reaction for 38 min. After the reaction, the slurry was poured out, coagulated, washed, and vacuum dried to obtain a macromolecular brominated ring-opening agent c (Mn is 4400, Mw / Mn is 1.93).

[0123] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 3.

[0124] (III) Preparation of Brominated SIS Thermoplastic Elastomer: Other conditions were the same as in Example 3, except that a macromolecular brominated ring-opening agent was not added during the preparation of the brominated SIS thermoplastic elastomer. Instead, a macromolecular brominated ring-opening agent c was added in an amount of 1.6 mol. Specifically, an epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 4.0 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to a reaction vessel. The pH of the solution was adjusted to 3.0 with propionic anhydride. 1.6 mol of macromolecular brominated ring-opening agent c and 0.07 mol of ZrCl4 were added, and the mixture was heated to 135°C for a ring-opening reaction for 3.6 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0125] Comparative Example 3

[0126] (I) Preparation of macromolecular brominated ring-opening agent: Other conditions are the same as in Example 4, except that styrene is not added in the preparation of macromolecular brominated ring-opening agent. That is: in a 4L stainless steel reactor with a jacket, inert gas is introduced for replacement, and 2300g of cyclohexane, 440g of 2,3-dibromo-1-propene and 185mmol of THF are added to the polymerization reactor in sequence. The stirring speed is 560rpm, and when the temperature is raised to 61°C, 112mmol of n-butyllithium is added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reaches 100%, 22g of 4-vinylbenzoic acid is added to the polymerization reactor for acidification reaction for 42min. After the reaction, the slurry is poured out, coagulated, washed and vacuum dried to obtain macromolecular brominated ring-opening agent d (Mn is 3900, Mw / Mn is 2.03).

[0127] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 4.

[0128] (III) Preparation of Brominated SIS Thermoplastic Elastomer: Other conditions were the same as in Example 4, except that a macromolecular brominated ring-opening agent was not added during the preparation of the brominated SIS thermoplastic elastomer. Instead, a macromolecular brominated ring-opening agent d was added in an amount of 1.8 mol. Specifically, an epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 4.3 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to a reaction vessel. The pH of the solution was adjusted to 3.5 with propionic anhydride. 1.8 mol of macromolecular brominated ring-opening agent d and 0.09 mol of ZrCl4 were added, and the mixture was heated to 137°C for a ring-opening reaction for 3.7 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0129] Comparative Example 4

[0130] (I) Preparation of macromolecular brominated ring-opening agent: Other conditions are the same as in Example 5, except that the amount of styrene added in the preparation of macromolecular brominated ring-opening agent is 30g. That is, in a 4L stainless steel reactor with a jacket, an inert gas is introduced for replacement, and 2400g of cyclohexane, 445g of 2,3-dibromo-1-propene and 192mmol of THF are added to the polymerization reactor in sequence. The stirring speed is 580rpm, and when the temperature is raised to 63℃, 107mmol of n-butyllithium is added to react. When the conversion rate of 2,3-dibromo-1-propene monomer reaches 100%, 30g of styrene is added to the polymerization reactor to continue the reaction. When the conversion rate of styrene monomer reaches 97%, 23g of 4-vinylbenzoic acid is added to the polymerization reactor for acidification reaction for 46min. After the reaction, the slurry is poured out, coagulated, washed, and vacuum dried to obtain macromolecular brominated ring-opening agent e (Mn is 4500, Mw / Mn is 2.16).

[0131] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 5.

[0132] (III) Preparation of Brominated SIS Thermoplastic Elastomer: Other conditions were the same as in Example 5, except that a macromolecular brominated ring-opening agent was not added during the preparation of the brominated SIS thermoplastic elastomer. Instead, a macromolecular brominated ring-opening agent e was added in an amount of 1.9 mol. Specifically, an epoxidized SIS thermoplastic elastomer containing 1 mol of epoxy groups was dissolved in xylene to prepare a 4.6 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to a reaction vessel. The pH of the solution was adjusted to 4.3 with propionic anhydride. 1.9 mol of macromolecular brominated ring-opening agent e and 0.11 mol of ZrCl4 were added, and the mixture was heated to 139°C for a ring-opening reaction for 3.9 hours. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0133] Comparative Example 5

[0134] (a) Preparation of macromolecular brominated ring-opening agents: Same as in Example 6.

[0135] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 6.

[0136] (III) Preparation of Brominated SIS Thermoplastic Elastomer: Other conditions were the same as in Example 6, except that the amount of macromolecular brominated ring-opening agent added during the preparation of the brominated SIS thermoplastic elastomer was 0.7 mol. Specifically, 1 mol of epoxidized SIS thermoplastic elastomer containing epoxy groups was dissolved in xylene to prepare a 5.0 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to the reaction vessel. When the pH of the solution was adjusted to 5.0 with butyric anhydride, 0.7 mol of macromolecular brominated ring-opening agent and 0.12 mol of ZrCl4 were added. The mixture was heated to 140°C for 4.0 hours for the ring-opening reaction. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0137] Comparative Example 6

[0138] (a) Preparation of epoxidized SIS thermoplastic elastomer: same as in Example 6.

[0139] (II) Preparation of Brominated SIS Thermoplastic Elastomer: Other conditions were the same as in Example 6, except that a large-molecule brominated ring-opening agent was not added during the preparation of the brominated SIS thermoplastic elastomer. Instead, a small-molecule ring-opening agent, maleic anhydride, was added in an amount of 2.0 mol. Specifically, 1 mol of epoxidized SIS thermoplastic elastomer containing epoxy groups was dissolved in xylene to prepare a 5.0 wt% epoxidized SIS thermoplastic elastomer solution, which was then added to the reaction vessel. The pH of the solution was adjusted to 5.0 with butyric anhydride. Then, 2.0 mol of maleic anhydride and 0.12 mol of ZrCl4 were added. The mixture was heated to 140°C for 4.0 hours for the ring-opening reaction. The resulting mixture was precipitated with ethanol, washed, and dried to obtain the brominated SIS thermoplastic elastomer. Sampling and Analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0140] Table 1 Properties of Brominated SIS Thermoplastic Elastomers

[0141]

[0142] As shown in Table 1, comparing Examples 1-7 with Comparative Examples 1-6, it is evident that the water contact angles of the brominated SIS thermoplastic elastomers prepared in Examples 1-7 are all smaller than those in Comparative Examples 1-6, and the peel strengths of the brominated SIS thermoplastic elastomers prepared in Examples 1-7 are all greater than those in Comparative Examples 1-6. This indicates that the macromolecular brominated ring-opening agent has a significant modifying effect on improving the polarity of SIS thermoplastic elastomers. From Examples 4 and Comparative Example 3, it can be seen that the macromolecular brominated ring-opening agent without PS blocks has significantly lower tensile strength than that containing PS blocks, indicating that the macromolecular brominated ring-opening agent prepared in this invention maintains sufficient raw rubber tensile strength for the SIS thermoplastic elastomer. From Examples 6 and Comparative Example 6, it can be seen that the macromolecular brominated ring-opening agent is significantly better than the common small-molecule brominated ring-opening agent, maleic anhydride, in reducing the water contact angle and improving the peel strength.

[0143] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a brominated SIS thermoplastic elastomer, characterized in that, Includes the following steps: Step 1 involves a block copolymerization reaction of 2,3-dibromo-1-propene and styrene, followed by the addition of 4-vinylbenzoic acid for an acidification reaction to obtain a ring-opening agent. Step 2: The polyisoprene segments in the SIS thermoplastic elastomer undergo an epoxidation reaction to obtain epoxidized SIS; Step 3: The ring-opening agent is reacted with the epoxidized SIS to obtain the brominated SIS thermoplastic elastomer; The mass ratio of 2,3-dibromo-1-propene, styrene, and 4-vinylbenzoic acid is (85.0–90.0):(10.0–15.0):(3.0–5.0); the molar ratio of the ring-opening agent to the epoxy group in the epoxidized SIS is greater than or equal to 1.

2. The method for preparing brominated SIS thermoplastic elastomer according to claim 1, characterized in that, Step 1 is as follows: 2,3-dibromo-1-propylene is subjected to a polymerization reaction. After the conversion rate of 2,3-dibromo-1-propylene monomer reaches 95%-100%, styrene is added to carry out a polymerization reaction. After the conversion rate of styrene monomer reaches 95%, 4-vinylbenzoic acid is added to carry out an acidification reaction to obtain a ring-opening agent.

3. The method for preparing brominated SIS thermoplastic elastomer according to claim 2, characterized in that, The polymerization reaction of 2,3-dibromo-1-propylene is carried out in a first solvent under the action of an initiator and a structure modifier; the initiator is a hydrocarbon monolithium compound, the structure modifier is a polar organic compound, and the first solvent is a hydrocarbon solvent; the molar ratio of the structure modifier to the initiator is (1.0~2.0):

1.

4. The method for preparing brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The block copolymerization reaction is carried out at a temperature of 55–65°C, the acidification reaction is carried out at a temperature of 55–65°C, and the acidification reaction is carried out for a time of 30–50 min.

5. The method for preparing brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The ring-opening agent has the following structure: Formula I: Where PS represents a styrene homopolymer block; n is the number of repeating units, n≥1.

6. The method for preparing the brominated SIS thermoplastic elastomer according to claim 5, characterized in that, The ring-opening agent has a number-average molecular weight of 4000–5000 and a molecular weight distribution of 1.76–2.

41.

7. The method for preparing the brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The epoxidation reaction of polyisoprene segments in SIS thermoplastic elastomers is carried out in a second solvent under the action of organic acids and peroxides.

8. The method for preparing the brominated SIS thermoplastic elastomer according to claim 7, characterized in that, The organic acid is selected from at least one of formic acid, acetic acid, benzoic acid and salicylic acid, and the molar ratio of the organic acid to the SIS thermoplastic elastomer is (0.05-1.0):1; the peroxide is hydrogen peroxide and / or peracetic acid, and the molar ratio of the peroxide to the SIS thermoplastic elastomer is (0.1-1.5):1; the second solvent is selected from at least one of chlorobenzene, benzene, toluene, xylene, chloroform, acetone and ethylbenzene.

9. The method for preparing the brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The epoxy degree of the epoxidized SIS is 7%-12%.

10. The method for preparing the brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The ring-opening reaction between the ring-opening agent and the epoxidized SIS is carried out under the action of a ring-opening catalyst, which is selected from at least one of zirconium tetrachloride, trifluoromethanesulfonic acid and imidazole; the molar ratio of the ring-opening catalyst to the epoxy group in the epoxidized SIS is (0.02-0.5):1; the molar ratio of the ring-opening agent to the epoxy group in the epoxidized SIS is (1.2-2.0):

1.

11. The method for preparing the brominated SIS thermoplastic elastomer according to claim 10, characterized in that, Before being mixed with the ring-opening agent, the epoxidized SIS is first mixed with an organic solvent, and the pH of the mixture is adjusted to 1-5; the molar ratio of epoxy groups, ring-opening agent and ring-opening catalyst in the epoxidized SIS is 100:(120-200):(4-12).

12. The method for preparing the brominated SIS thermoplastic elastomer according to claim 11, characterized in that, The pH of the mixture is adjusted to 1-5 using an acid anhydride, wherein the acid anhydride is selected from one or more of propionic anhydride, butyric anhydride, valeric anhydride, hexanoic anhydride, heptanoic anhydride, and octanoic anhydride.

13. The method for preparing the brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The ring-opening reaction temperature is 130–140°C, and the ring-opening reaction time is 3.0–4.0 hr.

14. The brominated SIS thermoplastic elastomer obtained by the preparation method according to any one of claims 1-13.

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