Low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer and preparation method thereof

Abstract

The invention provides a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer and a preparation method thereof.The preparation method comprises the steps that 1, cis-2-methyl-1, 4-dibromo-2-butene and allyl phosphate diester 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 the ring-opening agent and the epoxidized SIS to obtain a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer; wherein the mass ratio of the cis-2-methyl-1, 4-dibromo-2-butene to the allyl phosphate diester to the 4-vinyl benzoic acid is (30 to 70) to (30 to 40) to (3.0 to 5.0). The SIS thermoplastic elastomer provided by the invention improves the non-polar problem, and has good compatibility with other resins, the peel strength of a pressure-sensitive adhesive prepared from the SIS thermoplastic elastomer is high, and the SIS thermoplastic elastomer provided by the invention has good low temperature resistance and flame retardance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of styrene thermoplastic elastomers, and particularly relates to a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer and a preparation method thereof. BACKGROUND

[0002] SIS is a styrene thermoplastic elastomer composed of a styrene-isoprene-styrene triblock copolymer, and the middle block is polyisoprene. The structure has a methyl side chain, and thus has good cohesion and excellent adhesion. The microstructure determines that it has outstanding advantages when applied to adhesives, and becomes the main base material of hot melt pressure sensitive adhesive and is widely used in packaging, labeling, biological medicine and other fields. With the rapid development of new energy, electronic appliances, precision instruments and other fields, the annual growth rate of hot melt pressure sensitive adhesive exceeds 13%, and the high performance of hot melt pressure sensitive adhesive has become one of the current research hotspots.

[0003] However, as a non-polar polymer, SIS thermoplastic elastomer inevitably has poor compatibility with polar materials, poor bonding effect, poor oil resistance and poor tackiness, which makes the performance of SIS thermoplastic elastomer unable to meet the increasingly diversified application scenarios, becoming a bottleneck for the expansion of SIS thermoplastic elastomer materials.

[0004] Polarization refers to improving the polarity of the material by introducing polar groups, polar side chains or blending with polar substances to improve its adhesion and oil resistance. Polarization can further expand the application field of SIS thermoplastic elastomer, therefore, the polarization modification of SIS thermoplastic elastomer becomes the most effective method to solve the above problems. Polarization mainly includes polymerization of polar monomers and post-functionalization modification. The method of polymerization (mainly active anionic polymerization method) of polar monomers has great implementation difficulty and narrow range of selected polar monomers. The post-functionalization modification method mainly introduces polar groups or segments into the unsaturated double bonds of the isoprene chain in the SIS polymer molecular chain. The modified product has a clear structure, stable chemical properties, simple composition and high polarization efficiency, and is relatively easy to implement, becoming one of the hotspots of SIS thermoplastic elastomer polarization research.

[0005] Preparation of SIS with polar polyethylene oxide block (Gao Tan, Dalian: Dalian University of Technology, 2016) discloses that SIS-g-PEO is prepared by one-pot method using cyclohexane as solvent, n-butyllithium as main initiator, and triisobutylaluminum as co-initiator, after the completion of three-block polymerization of SIS, without adding terminator, but introducing polyethylene oxide (PEO) monomer as block. Studies show that the water contact angle of SIS-g-PEO is significantly reduced compared with SIS, the polarity is increased, and the polymer itself changes from non-polar polymer to medium-polar polymer. However, this method is difficult to implement, and the range of available polar monomers is narrow.

[0006] CN116515138A discloses a spiro-pyrane group modified SIS dynamic crosslinking network with force-induced color change characteristics. The spiro-pyrane group modified SIS dynamic crosslinking network SIS-SP-UPy has a main chain of styrene-isoprene-styrene SIS, and is modified by epoxy functionalization ESIS-hydroxyl functionalization SIS-OH of double bonds in the polyisoprene PI block of SIS, esterification reaction of isocyanate NCO and OH, double-end NCO functionalized spiro-pyrane SP as covalent bond crosslinking agent SP-NCO and NCO functionalized 2-ureido-4[1H]-pyrimidinone as dynamic hydrogen bond crosslinking agent UPy-NCO, and SP-NCO, UPy-NCO grafted to the side chain of SIS-OH. The obtained SIS-SP-UPy is a dynamic crosslinking network of SIS modified by SP group with covalent crosslinking and dynamic hydrogen bond crosslinking. The modified SIS is mainly dedicated to color change characteristics.

[0007] Therefore, how to improve the polarity of SIS thermoplastic elastomer and make it have more excellent application performance is a technical problem to be solved by those skilled in the art. SUMMARY

[0008] The main purpose of the present application is to provide a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer and a preparation method thereof, so as to solve the non-polar problem of SIS thermoplastic elastomer, improve the compatibility with other resins, improve the peel strength of the subsequently prepared pressure-sensitive adhesive, and the brominated SIS thermoplastic elastomer has good low-temperature resistance and flame retardance, which can meet the requirements of new energy, high-end electronics and biological medicine for low-temperature resistance and flame retardance of pressure-sensitive adhesive.

[0009] In order to achieve the above purpose, the present application provides a preparation method of a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, comprising the following steps:

[0010] Step 1, carrying out block copolymerization reaction of cis-2-methyl-1,4-dibromo-2-butene and allyl phosphate diester, then adding 4-vinylbenzoic acid for acidification reaction to obtain a ring-opening agent;

[0011] Step 2, epoxidation reaction of polyisoprene segment in SIS thermoplastic elastomer to obtain epoxidized SIS;

[0012] Step 3, ring-opening reaction of the ring-opening agent with the epoxidized SIS to obtain low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer;

[0013] The mass ratio of the cis-2-methyl-1,4-dibromo-2-butene, allyl phosphoric acid diester and 4-vinylbenzoic acid is (30-70):(30-40):(3.0-5.0).

[0014] The preparation method of the low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer, wherein the step 1 is: polymerization reaction of the cis-2-methyl-1,4-dibromo-2-butene, after the conversion rate of the cis-2-methyl-1,4-dibromo-2-butene monomer reaches 95%, polymerization reaction of the allyl phosphoric acid diester is carried out, after the conversion rate of the allyl phosphoric acid diester monomer reaches 97%, acidification reaction of the 4-vinylbenzoic acid is carried out to obtain the ring-opening agent.

[0015] The preparation method of the low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer, wherein the polymerization reaction of the cis-2-methyl-1,4-dibromo-2-butene is carried out in the presence of an initiator and a structure regulator in a first solvent; the initiator is a hydrocarbon monolithiation compound, the structure regulator is a polar organic compound, and the first solvent is a hydrocarbon solvent; the mass ratio of the cis-2-methyl-1,4-dibromo-2-butene, allyl phosphoric acid diester and 4-vinylbenzoic acid is (60-70):(30-40):(3.0-5.0); and the molar ratio of the structure regulator to the initiator is (1.0-2.0):1.

[0016] The preparation method of the low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer, wherein the temperature of the block copolymerization reaction is 75-85℃, the temperature of the acidification reaction is 75-85℃, and the acidification reaction time is 40-50min.

[0017] The preparation method of the low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer, wherein the ring-opening agent has the following formula I structure:

[0018]

[0019] wherein R is a linear alkyl group with 1-6 carbon atoms; n and m are the number of repeating units, n≥1 and m≥1.

[0020] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the number average molecular weight of the ring-opening agent is 2000-3000, and the molecular weight distribution is 1.93-2.26.

[0021] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the epoxidation reaction of the polyisoprene segment in the SIS thermoplastic elastomer is carried out in a second solvent under the action of an organic acid and a peroxide; and the molar ratio of the SIS thermoplastic elastomer, the organic acid and the peroxide is 100:(5-10):(20-40).

[0022] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the organic acid is at least one selected from formic acid, acetic acid, benzoic acid and salicylic acid, and the molar ratio of the organic acid to the SIS thermoplastic elastomer is (0.02-0.5):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; and the second solvent is at least one selected from chlorobenzene, benzene, toluene, xylene, trichloromethane, acetone and ethylbenzene.

[0023] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the epoxidation degree of the epoxidized SIS is 5%-8%.

[0024] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the ring-opening reaction of the ring-opening agent and the epoxidized SIS is carried out under the action of a ring-opening catalyst, the ring-opening catalyst is at least one selected from zirconium tetrachloride, trifluoromethanesulfonic acid and imidazole, the molar ratio of the ring-opening catalyst to the epoxy group in the epoxidized SIS is (0.01-0.2):1, and the molar ratio of the ring-opening agent to the epoxy group in the epoxidized SIS is (1.0-1.4):1.

[0025] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the epoxidized SIS is mixed with an organic solvent before being mixed with the ring-opening agent, and the pH value of the mixed solution is adjusted to 1-5; and the molar ratio of the epoxy group in the epoxidized SIS, the ring-opening agent and the ring-opening catalyst is 100:(100-140):(3-9).

[0026] The preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, wherein the pH value of the mixed solution is adjusted to 1-5 by using an anhydride, and the anhydride is one or more selected from propionic anhydride, butyric anhydride, valeric anhydride, hexanoic anhydride, heptanoic anhydride and octanoic anhydride.

[0027] The method for preparing low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to the present invention, wherein the ring-opening reaction temperature is 150-160°C and the ring-opening reaction time is 5.0-6.0 hr.

[0028] To achieve the above objectives, the present invention also provides a low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer obtained by the above preparation method.

[0029] The beneficial effects of this invention are:

[0030] (1) This invention uses cis-2-methyl-1,4-dibromo-2-butene and allyl phosphate diester as reactants, and synthesizes a macromolecular polar brominated ring-opening agent by end-acidification with 4-vinylbenzoic acid. This macromolecular polar brominated ring-opening agent integrates multiple long carbon chain ester groups and primary bromine structures into a single macromolecular chain, making full use of the "aggregation effect" of macromolecules, the "group effect" and "structural effect" of long carbon chain ester groups and bromomethyl groups. It can effectively disrupt the regularity and crystallinity of SIS thermoplastic elastomer chain segments with low addition amount, efficiently reduce the glass transition temperature (Tg) of SIS thermoplastic elastomer, and endow SIS thermoplastic elastomer with high breakage rate in low temperature environments below -20℃, exhibiting good low temperature resistance.

[0031] (2) The macromolecular polar brominated ring-opening agent combines the flame-retardant "phosphorus-halogen" atoms together and grafts them onto the main chain segment of the SIS thermoplastic elastomer through a ring-opening reaction. This avoids the migration and precipitation of the macromolecular polar brominated ring-opening agent in the SIS thermoplastic elastomer matrix. At the same time, the bromine atom has a stable primary bromine structure. Under the synergistic effect of these two aspects, the flame-retardant effect of "phosphorus-halogen" is significantly enhanced, and the high efficiency and durability of flame retardancy can be obtained, which can meet the requirements of new energy, high-end electronics industry and precision instruments for the flame retardancy of pressure-sensitive adhesives.

[0032] (3) In the preparation process of low-temperature resistant and flame-retardant brominated SIS thermoplastic elastomer, there is no emission of volatile organic compounds (VOCs) and by-product HBr. The preparation method is green and environmentally friendly, with a low addition ratio and significant modification effect, making it suitable for industrial production.

[0033] Instruction manual illustrations

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0035] Figure 1 The infrared spectrum of the ring-opening agent in Example 1 of this invention is shown.

[0036] from Figure 1 It can be seen from this that, in the wavenumber range of 630–550 cm⁻¹ -1The characteristic peak of primary bromine appears; the sharp absorption peak of ester group appears at wave number of 1750-1730 cm -1 The characteristic peak of primary bromine appears; the sharp absorption peak of ester group appears at wave number of 1750-1730 cm -1 The characteristic peak of primary bromine appears; the sharp absorption peak of ester group appears at wave number of 1750-1730 cm -1 The characteristic peak of primary bromine appears; the sharp absorption peak of ester group appears at wave number of 1750-1730 cm DETAILED DESCRIPTION

[0037] The technical solutions of the present application are described in detail below. The following embodiments are implemented on the premise of the technical solutions of the present application, and detailed implementation processes are given. However, the protection scope of the present application is not limited to the following embodiments. The structural or experimental methods not specified in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the "parts" mentioned in the present application refer to mass parts, and the "ratio" mentioned in the present application refers to mass ratio.

[0038] The present application first synthesizes a ring-opening agent, i.e., a macromolecular polar brominated ring-opening agent, by using 4-vinylbenzoic acid, cis-2-methyl-1,4-dibromo-2-butene and allyl phosphate diester; secondly, an epoxidized SIS is obtained by epoxidizing the PI (polyisoprene) segment containing a double bond in the SIS thermoplastic elastomer; and finally, a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer is prepared by ring-opening reaction of the macromolecular polar brominated ring-opening agent and the epoxidized SIS.

[0039] In an embodiment, the preparation method of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer of the present application comprises the following steps:

[0040] Step 1: block copolymerization of cis-2-methyl-1,4-dibromo-2-butene and allyl phosphate diester, and then acidification reaction by adding 4-vinylbenzoic acid to obtain a ring-opening agent;

[0041] Step 2: epoxidation of the polyisoprene segment in the SIS thermoplastic elastomer to obtain an epoxidized SIS;

[0042] Step 3: ring-opening reaction of the ring-opening agent and the epoxidized SIS to obtain a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer.

[0043] The SIS thermoplastic elastomer of the present application improves the non-polar problem and has good compatibility with other resins. The pressure-sensitive adhesive prepared therefrom has high peel strength. Moreover, the SIS thermoplastic elastomer of the present application has good low-temperature resistance and flame retardance, and can meet the requirements of new energy, high-end electronic industry and biological medicine for low-temperature resistance and flame retardance of pressure-sensitive adhesive.

[0044] In an embodiment, step 1 is: polymerizing cis-2-methyl-1,4-dibromo-2-butene, then adding allyl phosphoric acid diester to polymerize, and then adding 4-vinylbenzoic acid to acidize, to obtain the ring-opening agent.

[0045] Step 1 of the present application is carried out in an inert gas atmosphere, which is not particularly limited in the present application as long as it does not affect the reaction, such as nitrogen, argon, etc. In another embodiment, the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 95%, and further reaches 100%, then allyl phosphoric acid diester is added, the conversion rate of allyl phosphoric acid diester monomer reaches more than 97% and less than 100%, then 4-vinylbenzoic acid is added for single-end capping, after the reaction, the glue slurry is poured out, agglomerated, washed, and vacuum dried to obtain the macromolecular polar brominated ring-opening agent.

[0046] In yet another embodiment, the polymerization of cis-2-methyl-1,4-dibromo-2-butene is carried out in a first solvent in the presence of an initiator and a structure regulator.

[0047] The initiator can be a hydrocarbyl monolithium compound, such as R'Li, wherein 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 an embodiment, the hydrocarbyl monolithium compound is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthyllithium, cyclohexyllithium, and dodecyl lithium, preferably n-butyllithium. The amount of initiator added is not particularly limited in the present application, in an embodiment, it is determined by the molecular weight of the target product macromolecular polar brominated ring-opening agent, for example, the amount of substance of the hydrocarbyl monolithium compound is calculated by the following formula:

[0048] Molar amount (mol) of the hydrocarbyl monolithium compound = total mass m (g) of the glue / molecular weight M (g / mol)

[0049] wherein the total mass of the glue refers to the total mass of cis-2-methyl-1,4-dibromo-2-butene and allyl phosphoric acid diester, and the molecular weight refers to the molecular weight of the target product macromolecular polar brominated ring-opening agent.

[0050] The structure regulator is a polar organic compound, which can produce a solvation effect in the polymerization system. In an embodiment, the polar organic compound is selected from one of diethylene glycol dimethyl ether (DGE), tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether (DME), and triethylamine, preferably tetrahydrofuran (THF).

[0051] The first solvent is a hydrocarbon solvent, which can be a straight-chain alkane, an aromatic hydrocarbon, and a cycloalkane, for example, one selected from pentane, hexane, octane, heptane, and cyclohexane, preferably cyclohexane.

[0052] In an embodiment, the mass ratio of the first solvent, cis-2-methyl-1,4-dibromo-2-butene, allyl phosphoric acid diester, and 4-vinylbenzoic acid is (400-500):(60-70):(30-40):(3.0-5.0); and the molar ratio of the structure regulator to the initiator is (1.0-2.0):1. The allyl phosphoric acid diester can be one of dimethyl allyl phosphoric acid diester, diethyl allyl phosphoric acid diester, dipropyl allyl phosphoric acid diester, dibutyl allyl phosphoric acid diester, dipentyl allyl phosphoric acid diester, and dihexyl allyl phosphoric acid diester, preferably diethyl allyl phosphoric acid diester.

[0053] In an embodiment, the temperature of the block copolymerization reaction is 75-85°C, the temperature of the acidification reaction is 75-85°C, and the acidification reaction time is 40-50 min. In another embodiment, the reaction is carried out under stirring at a stirring speed of 500-600 rpm.

[0054] In a specific embodiment, step 1 is: in a jacketed stainless steel reactor, inert gas is introduced to replace the air, and then the first solvent, cis-2-methyl-1,4-dibromo-2-butene, and the structure regulator are sequentially added to the polymerization kettle, and then the initiator is added after stirring and temperature rising, and then the allyl phosphoric acid diester is added to the polymerization kettle when the monomer conversion rate of cis-2-methyl-1,4-dibromo-2-butene reaches 100%, and then the 4-vinylbenzoic acid is added to the polymerization kettle for acidification reaction, and then the rubber slurry is poured out after the reaction, and then the rubber slurry is coagulated, washed, and vacuum dried to obtain the macromolecular polar ring-opening agent.

[0055] In an embodiment, the ring-opening agent of the present application has the following formula I structure:

[0056]

[0057] wherein R is a straight-chain alkyl group with 1-6 carbon atoms; n and m are the number of repeating units, 10≥n≥1, and 10≥m≥1. The cis-2-methyl-1,4-dibromo-2-butene repeating unit is terminated by hydrogen.

[0058] In an embodiment, the number average molecular weight (Mn) of the ring-opening agent is 2000-3000, and the molecular weight distribution (Mw / Mn) is 1.93-2.26.

[0059] Step 2 is: the polyisoprene chain segment in the SIS thermoplastic elastomer is subjected to epoxidation reaction to obtain epoxidized SIS.

[0060] The SIS thermoplastic elastomer is not particularly limited in the present application, and in one embodiment, the SIS thermoplastic elastomer has a number average molecular weight (Mn) of 130,000 to 200,000.

[0061] The method for the epoxidation of the polyisoprene segment in the SIS thermoplastic elastomer is not particularly limited in the present application, and the method can be conventional in the art. In one embodiment, the epoxidation of the polyisoprene segment in the SIS thermoplastic elastomer is carried out in a second solvent in the presence of an organic acid and a peroxide. The organic acid can be at least one selected from the group consisting of formic acid, acetic acid, benzoic acid and salicylic acid, and the molar ratio of the organic acid to the SIS thermoplastic elastomer is (0.02 to 0.5) : 1, preferably (0.05 to 0.10) : 1; the peroxide can be hydrogen peroxide and / or peracetic acid, and the molar ratio of the peroxide to the SIS thermoplastic elastomer is (0.1 to 1.5) : 1, preferably (0.2 to 0.4) : 1; and the second solvent can be at least one selected from the group consisting of chlorobenzene, benzene, toluene, xylene, trichloromethane, acetone and ethylbenzene. The molar ratio of the SIS thermoplastic elastomer, the organic acid and the peroxide is 100 : (5 to 10) : (20 to 40).

[0062] In one embodiment, the SIS thermoplastic elastomer is mixed with the second solvent to form a SIS thermoplastic elastomer solution, which is then added to a reaction kettle, and then the organic acid and the peroxide are sequentially added to the reaction kettle to carry out the epoxidation reaction. The resulting product is precipitated by ethanol, washed and dried to obtain the epoxidized SIS thermoplastic elastomer.

[0063] 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%.

[0064] In one embodiment, the epoxidation reaction temperature is 60 to 70°C, and the epoxidation reaction time is 3.0 to 5.0 hours. In another embodiment, the epoxidized SIS has an epoxide degree of 5% to 8%. The present application grafts the ring-opening agent to the PI (isoprene homopolymer) segment in the SIS thermoplastic elastomer through the ring-opening reaction of the carboxyl group and the epoxy group. During the reaction, if the epoxide degree of the epoxidized SIS thermoplastic elastomer is too high, it is easy to cause a large number of entanglements of the branched chains, causing the gelation phenomenon and destroying the ductility of the SIS; if the epoxide degree is too low, the branched chains containing bromine introduced by the reaction are less, and the modification effect is not obvious. Therefore, the epoxide degree of the epoxidized SIS thermoplastic elastomer of the present application is 5% to 8%.

[0065] The degree of epoxidation in the epoxidized SIS refers to the degree of epoxidation of the unsaturated double bonds in the SIS, that is, the number of epoxy groups in the epoxidized SIS accounts for the percentage of the number of unsaturated double bonds in the SIS before epoxidation. The degree of epoxidation is an important index for characterizing the degree of epoxidation of the epoxidized SIS, and is usually determined more accurately by nuclear magnetic resonance.

[0066] Step 3 is to make the ring-opening agent react with the epoxidized SIS to obtain a low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer.

[0067] In an embodiment, the ring-opening reaction of the ring-opening agent with 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), triflic acid and imidazole, and is preferably zirconium tetrachloride (ZrCl4). The molar ratio of the ring-opening catalyst to the epoxy groups in the epoxidized SIS is (0.01-0.2):1, and is preferably (0.03-0.09):1. In order to ensure that the ring-opening agent can be fully grafted onto the SIS thermoplastic elastomer, the number of moles of carboxyl groups in the ring-opening agent should be greater than the number of moles 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 (1.0-1.4):1.

[0068] In an embodiment, the epoxidized SIS is mixed with an organic solvent to prepare an epoxidized SIS thermoplastic elastomer solution, which is added to a reaction kettle, the pH value of the mixture is adjusted to 1-5, the ring-opening agent and the ring-opening catalyst are added, and the ring-opening reaction is carried out by heating. The mixture after the reaction is precipitated with ethanol, washed and dried to obtain a low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer. The processes of precipitation, washing and drying are well known to those skilled in the art, and can be reasonably set according to the conditions in the preparation process of the brominated SIS thermoplastic elastomer, and the present application is not particularly limited.

[0069] In an embodiment, the mass concentration of the epoxidized SIS thermoplastic elastomer in the epoxidized SIS thermoplastic elastomer solution is 1.0wt%-10.0wt%, and is preferably 3.0wt%-5.0wt%. The organic solvent can be selected from at least one of chlorobenzene, benzene, toluene, xylene, trichloromethane, acetone and ethylbenzene. The molar ratio of the epoxy groups in the epoxidized SIS, the ring-opening agent and the ring-opening catalyst is 100:(100-140):(3-9). In another embodiment, an acid anhydride is used to adjust the pH value 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.

[0070] In another embodiment, the ring-opening reaction temperature is 150-160°C, and the ring-opening reaction time is 5.0-6.0 hr.

[0071] The preparation process of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer is carried out in an oxygen-free, water-free and inert gas environment. The inert gas can be nitrogen or a gas of group 0 elements in the periodic table except radon, preferably argon. The reaction device can be replaced before the reaction, for example, 3-5 times. The reaction device of the present application can be a reaction kettle, such as a loop reactor or a tank reactor, preferably a tank reactor.

[0072] The present application also provides a low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer obtained by the above preparation method. Compared with SIS thermoplastic elastomer, it not only has a certain polarity, improves the compatibility with other polar resins, greatly improves the peel strength of the subsequently prepared pressure-sensitive adhesive, effectively reduces the glass transition temperature (Tg), improves the low-temperature resistance, avoids the high material breakage rate, and avoids the occurrence of tack loss and delamination in low-temperature environment below-20℃. In addition, it also improves the oxygen index of the elastomer, and gives it the characteristics of high efficiency and durability of flame retardance. The low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer of the present application can meet the requirements of new energy, high-end electronic industry and biological medicine for low-temperature resistance and flame retardance of pressure-sensitive adhesive.

[0073] To make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0074] (1) Raw material source:

[0075] SIS thermoplastic elastomer, China Petroleum Petrochemical Research Institute

[0076] Diethyl allylphosphonate, purity 98%, Shanghai Mayre Chemical Technology Co., Ltd.

[0077] Cis 2-methyl-1,4-dibromo-2-butene, polymer grade, Hubei Xingheng Industry Technology Co., Ltd.

[0078] 4-Vinylbenzoic acid, purity 98%, Condus Chemical Industry (Hubei) Co., Ltd.

[0079] Zirconium chloride (ZrCl4), purity 99%, Wuxi Yaodexin Chemical Products Co., Ltd.

[0080] n-Butyllithium, purity 98%, Nanjing Tonglian Chemical Co., Ltd.

[0081] Other reagents are commercially available industrial products

[0082] (2) Analysis test method:

[0083] Determination of molecular weight and molecular weight distribution: 2414 gel permeation chromatograph (GPC) produced by Waters Company of the United States was used for determination. Poly-cis 2-methyl-1,4-dibromo-2-butene standard sample was used as correction curve, the mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection amount was 50 μL, the elution time was 40 min, and the flow rate was 1 mL·min -1 .

[0084] Determination of epoxy degree: nuclear magnetic resonance hydrogen spectrum test was used, Shimadzu UNITY 300 type nuclear magnetic resonance hydrogen spectrometer was used, the prepared epoxidized SIS was dissolved in deuterated chloroform to prepare a 1% mass fraction solution for determination.

[0085] Epoxy degree calculation formula of epoxidized SIS (ESIS):

[0086]

[0087] Wherein, A 2.70 is the integral area of the epoxy group peak in ESIS, A 5.12 is the integral area of the unsaturated double bond C=C peak in ESIS.

[0088] Preparation of standard sample: low-temperature-resistant, flame-retardant brominated SIS thermoplastic elastomer was cut into small rubber blocks and placed in a beaker, heated in an oven at 180℃ for 40 minutes, and after the rubber block was completely melted, coating was carried out, the coating substrate was release paper, and a layer of PET film was attached to the release paper at the same time after coating, the thickness of PET was 100 μm, the thickness of release paper was 50 μm, and the coating thickness was 30-40 μm. After the coated PET film was cured at room temperature for 24 hours, the product performance test was carried out.

[0089] Determination of glass transition temperature (Tg): DSC was used to measure the glass transition temperature of the product. The instrument model is DSC1, the company is Mettler Company of Switzerland, the temperature rising range is-80-80℃, and the temperature rising rate is 10℃ / min.

[0090] Determination of material breaking rate: the coated brominated SIS thermoplastic elastomer pressure-sensitive adhesive tape was cured at room temperature for 24 hours, attached to the packaging box paperboard, and the roller in GB / T 4851-2014 Test method for adhesion of adhesive tape was used for roll pressing and bonding. After the bonded board was placed in a refrigerator, the temperature was set to-20℃, and the temperature was kept for 2 hours, 90° peeling was carried out in the refrigerator, and the area ratio of the area of the paperboard adhered and broken was the material breaking rate.

[0091] Peeling strength test: The method in standard GB / T 2792—2014 was performed.

[0092] Determination of oxygen index: The method described in GB10707—1989 was performed.

[0093] Aging resistance test: The method in standard GB / T 3512—2014 was performed.

[0094] Example 1

[0095] (I) Preparation of macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, replace with inert gas, add 2000g cyclohexane, 300g cis-2-methyl-1,4-dibromo-2-butene and 252mmol THF into the polymerization kettle, the stirring speed is 500rpm, when the temperature is raised to 75℃, add 252mmol n-butyllithium for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, then add 200g allyl diethyl phosphate into the polymerization kettle for further reaction, when the conversion rate of allyl diethyl phosphate monomer reaches 97%, then add 15g 4-vinylbenzoic acid into the polymerization kettle for acidification reaction for 40min, after reaction, pour out the glue slurry, wash and vacuum dry to obtain macromolecular polar brominated ring-opening agent (Mn is 2000, Mw / Mn is 1.93).

[0096] (II) Preparation of epoxidized SIS thermoplastic elastomer: 1mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a 5.0wt% SIS thermoplastic elastomer solution, which was added into the reaction kettle, then 0.05mol of formic acid and 0.2mol of hydrogen peroxide were sequentially added, and the temperature was raised to 60℃ for epoxidation reaction for 3.0hr, the obtained product was precipitated with ethanol, washed and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree is 5.0%).

[0097] (III) Preparation of low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: 1mol of epoxidized SIS thermoplastic elastomer was dissolved in xylene to prepare a 3.0wt% epoxidized SIS thermoplastic elastomer solution, which was added into the reaction kettle, the pH of the solution was adjusted to 1.0 with propionic anhydride, 1.0mol of macromolecular polar brominated ring-opening agent and 0.03mol of ZrCl4 were added, and the temperature was raised to 150℃ for ring-opening reaction for 5.0hr, the mixed solution after reaction was precipitated with ethanol, washed and dried to obtain low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0098] Example 2

[0099] (1) Preparation of macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, replace with inert gas, add 2100g cyclohexane, 310g cis-2-methyl-1,4-dibromo-2-butene and 274mmol THF into the polymerization kettle, stir at 520rpm, when the temperature is raised to 77°C, add 240mmol n-butyllithium for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, then add 190g allyl dipropyl phosphate into the polymerization kettle for further reaction, when the conversion rate of allyl dipropyl phosphate monomer reaches 97%, add 18g 4-vinylbenzoic acid into the polymerization kettle for acidification reaction for 43min, after reaction, pour out the glue slurry, wash and vacuum dry to obtain macromolecular polar brominated ring-opening agent (Mn is 2200, Mw / Mn is 1.98).

[0100] (2) Preparation of epoxidized SIS thermoplastic elastomer: Dissolve 1mol SIS thermoplastic elastomer in toluene to prepare a 6.0wt% SIS thermoplastic elastomer solution, add into the reaction kettle, then add 0.06mol formic acid and 0.26mol hydrogen peroxide into the reaction kettle in turn, heat to 68°C for epoxidation reaction for 3.6hr, the obtained product is precipitated with ethanol, washed and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree is 5.7%).

[0101] (3) Preparation of low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: Dissolve 1mol epoxidized SIS thermoplastic elastomer in xylene to prepare a 3.4wt% epoxidized SIS thermoplastic elastomer solution, add into the reaction kettle, adjust the pH of the solution to 2.2 with butyric anhydride, add 1.12mol macromolecular polar brominated ring-opening agent and 0.04mol ZrCl4, heat to 152°C for ring-opening reaction for 5.3hr, precipitate the mixed solution after reaction with ethanol, wash and dry to obtain low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, the test performance is shown in Table 1.

[0102] Example 3

[0103] (1) Preparation of macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, replace with inert gas, add 2200g cyclohexane, 320g cis-2-methyl-1,4-dibromo-2-butene and 283mmol THF into the polymerization kettle, stir at 550rpm, when the temperature is raised to 80°C, add 205mmol n-butyllithium for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, then add 180g allyl diethyl phosphate into the polymerization kettle for further reaction, when the conversion rate of allyl diethyl phosphate monomer reaches 97%, then add 20g 4-vinylbenzoic acid into the polymerization kettle for acidification reaction for 45min, after reaction, pour out the glue slurry, wash and vacuum dry to obtain macromolecular polar brominated ring-opening agent (Mn is 2500, Mw / Mn is 2.06).

[0104] (2) Preparation of epoxidized SIS thermoplastic elastomer: Dissolve 1mol SIS thermoplastic elastomer in toluene to prepare a 7.0wt% SIS thermoplastic elastomer solution, add into the reaction kettle, then add 0.07mol formic acid and 0.29mol hydrogen peroxide into the reaction kettle in sequence, heat to 65°C for epoxidation reaction for 4.0hr, the obtained product is precipitated with ethanol, washed and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree is 6.3%).

[0105] (3) Preparation of low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: Dissolve 1mol epoxidized SIS thermoplastic elastomer in dimethylbenzene to prepare a 4.1wt% epoxidized SIS thermoplastic elastomer solution, add into the reaction kettle, adjust the pH of the solution to 3.5 with propionic anhydride, then add 1.21mol macromolecular polar brominated ring-opening agent and 0.05mol ZrCl4, heat to 155°C for ring-opening reaction for 5.5hr, the reaction mixture is precipitated with ethanol, washed and dried to obtain low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, the test performance is shown in Table 1.

[0106] Example 4

[0107] (1) Preparation of macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, replace with inert gas, add 2300g cyclohexane, 330g cis-2-methyl-1,4-dibromo-2-butene and 290mmol THF into the polymerization kettle, stir at 560rpm, when the temperature is raised to 81°C, add 187mmol n-butyllithium for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, then add 170g allyl phosphate dibutyl ester into the polymerization kettle for further reaction, when the conversion rate of allyl phosphate dibutyl ester monomer reaches 97%, then add 22g 4-vinylbenzoic acid into the polymerization kettle for acidification reaction for 47min, after reaction, pour out the glue slurry, wash and vacuum dry to obtain macromolecular polar brominated ring-opening agent (Mn is 2700, Mw / Mn is 2.12).

[0108] (2) Preparation of epoxidized SIS thermoplastic elastomer: 1mol of SIS thermoplastic elastomer is dissolved in toluene to prepare an SIS thermoplastic elastomer solution with a mass fraction of 8.0wt%, which is added into a reaction kettle, then 0.08mol of acetic acid and 0.33mol of hydrogen peroxide are sequentially added into the reaction kettle, the temperature is raised to 67°C, and epoxidation reaction is carried out for 4.5hr, the obtained product is precipitated by ethanol, washed and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree is 7.1%).

[0109] (3) Preparation of low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: 1mol of epoxidized SIS thermoplastic elastomer is dissolved in dimethylbenzene to prepare an epoxidized SIS thermoplastic elastomer solution with a mass fraction of 4.3wt%, which is added into a reaction kettle, when the pH of the solution is adjusted to 4.0 by hexanoic anhydride, 1.28mol of macromolecular polar brominated ring-opening agent and 0.07mol of ZrCl4 are added, and the temperature is raised to 156°C, and ring-opening reaction is carried out for 5.7hr, the mixed solution after reaction is precipitated by ethanol, washed and dried to obtain low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0110] Example 5

[0111] (1) Preparation of macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, the inert gas was introduced to replace the air, and then 2400 g of cyclohexane, 340 g of cis-2-methyl-1,4-dibromo-2-butene and 300 mmol of THF were sequentially added to the polymerization kettle. The stirring speed was 590 rpm, and the temperature was raised to 83°C. Then 180 mmol of n-butyllithium was added for reaction. When the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reached 100%, 160 g of allyl diethyl phosphate was added to the polymerization kettle for further reaction. When the conversion rate of allyl diethyl phosphate monomer reached 97%, 23 g of 4-vinylbenzoic acid was added to the polymerization kettle for acidification reaction for 48 min. After the reaction, the gel was poured out, washed, and vacuum dried to obtain the macromolecular polar brominated ring-opening agent (Mn2800, Mw / Mn2.19).

[0112] (2) Preparation of epoxidized SIS thermoplastic elastomer: 1 mol of SIS thermoplastic elastomer was dissolved in toluene to prepare a SIS thermoplastic elastomer solution with a mass fraction of 9.2 wt%, which was then added to the reaction kettle. Then 0.09 mol of formic acid and 0.38 mol of hydrogen peroxide were sequentially added to the reaction kettle. The temperature was raised to 69°C, and the epoxidation reaction was carried out for 4.8 hr. The obtained product was precipitated with ethanol, washed, and dried to obtain the epoxidized SIS thermoplastic elastomer (epoxy degree 7.7%).

[0113] (3) Preparation of low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: 1 mol of epoxidized SIS thermoplastic elastomer was dissolved in xylene to prepare an epoxidized SIS thermoplastic elastomer solution with a mass fraction of 4.8 wt%. When the pH of the solution was adjusted to 4.8 with propionic anhydride, 1.35 mol of macromolecular polar brominated ring-opening agent and 0.08 mol of ZrCl4 were added. The temperature was raised to 158°C, and the ring-opening reaction was carried out for 5.8 hr. The reaction mixture was precipitated with ethanol, washed, and dried to obtain the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer. The test performance is shown in Table 1.

[0114] Example 6

[0115] (1) Preparation of macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, the inert gas was introduced to replace the air, 2500g cyclohexane, 350g cis-2-methyl-1,4-dibromo-2-butene and 336mmol THF were sequentially added into the polymerization kettle, the stirring speed was 600rpm, when the temperature was raised to 85°C, 168mmol n-butyllithium was added for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reached 100%, then 150g allyl diethyl phosphate was added into the polymerization kettle for further reaction, when the conversion rate of allyl diethyl phosphate monomer reached 97%, 25g 4-vinylbenzoic acid was added into the polymerization kettle for acidification reaction for 40min, after reaction, the gel was poured out, washed and vacuum dried to obtain macromolecular polar brominated ring-opening agent (Mn is 3000, Mw / Mn is 2.26).

[0116] (2) Preparation of epoxidized SIS thermoplastic elastomer: 1mol SIS thermoplastic elastomer was dissolved in toluene to prepare a 10.0wt% SIS thermoplastic elastomer solution which was added into the reaction kettle, then 0.10mol formic acid and 0.40mol hydrogen peroxide were sequentially added into the reaction kettle, the temperature was raised to 70°C for epoxidation reaction for 5.0hr, the obtained product was precipitated by ethanol, washed and dried to obtain epoxidized SIS thermoplastic elastomer (epoxy degree is 8.0%).

[0117] (3) Preparation of low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: 1mol epoxidized SIS thermoplastic elastomer was dissolved in chlorobenzene to prepare a 5.0wt% epoxidized SIS thermoplastic elastomer solution which was added into the reaction kettle, butyric anhydride was used to adjust the pH of the solution to 5.0, 1.40mol macromolecular polar brominated ring-opening agent and 0.09mol ZrCl4 were added, when the temperature was raised to 160°C, ring-opening reaction was carried out for 6.0hr, the mixed solution after reaction was precipitated by ethanol, washed and dried to obtain low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, the test performance is shown in Table 1.

[0118] Example 7

[0119] (1) Preparation of the macromolecular polar brominated ring-opening agent: other conditions are the same as in Example 3, except that the amount of cis-2-methyl-1,4-dibromo-2-butene added in the preparation of the macromolecular polar brominated ring-opening agent is 200 g, i.e. in a 4 L jacketed stainless steel reactor, after replacement with inert gas, 2200 g of cyclohexane, 200 g of cis-2-methyl-1,4-dibromo-2-butene and 283 mmol of THF are sequentially added to the polymerization kettle, the stirring speed is 550 rpm, when the temperature is raised to 80°C, 205 mmol of n-butyllithium is added for reaction, when the monomer conversion rate of cis-2-methyl-1,4-dibromo-2-butene reaches 100%, then 180 g of allyl diethyl phosphate is added to the polymerization kettle for further reaction, when the monomer conversion rate of allyl diethyl phosphate reaches 97%, 20 g of 4-vinylbenzoic acid is added to the polymerization kettle for acidification reaction for 45 min, after reaction, the gel is poured out, washed and vacuum dried to obtain the macromolecular polar brominated ring-opening agent c (Mn is 1900 and Mw / Mn is 2.01).

[0120] (2) Preparation of the epoxidized SIS thermoplastic elastomer: same as in Example 3.

[0121] (3) Preparation of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: other conditions are the same as in Example 3, except that in the preparation of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, the macromolecular polar brominated ring-opening agent is not added, but the macromolecular polar brominated ring-opening agent c is added, and the amount of addition is 1.21 mol, i.e. 1 mol of the epoxidized SIS thermoplastic elastomer is dissolved in xylene to prepare a 4.1 wt% epoxidized SIS thermoplastic elastomer solution which is added to the reaction kettle, when the pH of the solution is adjusted to 3.5 with propionic anhydride, 1.21 mol of the macromolecular polar brominated ring-opening agent c and 0.05 mol of ZrCl4 are added, and when the temperature is raised to 155°C, the ring-opening reaction is carried out for 5.5 hr, the mixed solution after reaction is precipitated with ethanol, washed and dried to obtain the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0122] Example 8

[0123] (1) Preparation of the macromolecular polar brominated ring-opening agent: same as in Example 6.

[0124] (2) Preparation of the epoxidized SIS thermoplastic elastomer: same as in Example 6.

[0125] (Three) Preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer: other conditions are the same as example 6, the difference is that the low temperature resistant, flame retardant brominated SIS thermoplastic elastomer is prepared by adding 0.65 mol of macromolecular polar brominated ring opening agent: 1 mol of epoxidized SIS thermoplastic elastomer is dissolved in chlorobenzene to prepare a 5.0wt% epoxidized SIS thermoplastic elastomer solution, which is added to the reaction kettle, and when the pH of the solution is adjusted to 5.0 with butyric anhydride, 0.65 mol of macromolecular polar brominated ring opening agent and 0.09 mol of ZrCl4 are added, and when heated to 160℃, the ring opening reaction is carried out for 6.0 hr, and the reaction mixture is precipitated with ethanol, washed and dried to obtain the low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0126] Example 9

[0127] (One) Preparation of macromolecular polar brominated ring opening agent: in a 4L stainless steel reactor with a jacket, replace with inert gas, add 2450g of cyclohexane, 345g of cis-2-methyl-1,4-dibromo-2-butene and 300mmol of THF to the polymerization kettle, stir at a speed of 590rpm, heat to 83℃, then add 180mmol of n-butyllithium for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, then add 155g of allyl phosphate dibutyl ester to the polymerization kettle for further reaction, when the conversion rate of allyl phosphate dibutyl ester monomer reaches 97.6%, then add 23g of 4-vinylbenzoic acid to the polymerization kettle for acidification reaction for 48min, after reaction, pour out the glue slurry, wash and vacuum dry to obtain the macromolecular polar brominated ring opening agent (Mn2830, Mw / Mn2.18).

[0128] (Two) Preparation of epoxidized SIS thermoplastic elastomer: same as example 5.

[0129] (Three) Preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer: 1 mol of epoxidized SIS thermoplastic elastomer is dissolved in xylene to prepare a 4.9wt% epoxidized SIS thermoplastic elastomer solution, which is added to the reaction kettle, and when the pH of the solution is adjusted to 4.9 with propionic anhydride, 1.32 mol of macromolecular polar brominated ring opening agent and 0.09 mol of ZrCl4 are added, and when heated to 159℃, the ring opening reaction is carried out for 5.9 hr, and the reaction mixture is precipitated with ethanol, washed and dried to obtain the low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0130] Example 10

[0131] (1) Preparation of the macromolecular polar brominated ring-opening agent: In a 4L jacketed stainless steel reactor, inert gas was introduced to replace the air, 2500g cyclohexane, 350g cis-2-methyl-1,4-dibromo-2-butene and 336mmol THF were sequentially added into the polymerization kettle, the stirring speed was 600rpm, when the temperature was raised to 85°C, 168mmol n-butyllithium was added for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reached 100%, 150g dimethyl allyl phosphate was then added into the polymerization kettle for further reaction, when the conversion rate of dimethyl allyl phosphate monomer reached 98.3%, 25g 4-vinylbenzoic acid was added into the polymerization kettle for acidification reaction for 40min, after the reaction, the glue slurry was poured out, agglomerated, washed and vacuum dried to obtain the macromolecular polar brominated ring-opening agent (Mn was 2950, Mw / Mn was 2.24).

[0132] (2) Preparation of the epoxidized SIS thermoplastic elastomer: same as Example 6.

[0133] (3) Preparation of the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer: 1mol of the epoxidized SIS thermoplastic elastomer was dissolved in chlorobenzene to prepare a 5.0wt% epoxidized SIS thermoplastic elastomer solution which was added into the reaction kettle, butyric anhydride was used to adjust the pH of the solution to 5.0, 1.38mol of the macromolecular polar brominated ring-opening agent and 0.87mol of ZrCl4 were added, heating to 160°C, ring-opening reaction was carried out for 6.0hr, the mixed solution after the reaction was precipitated with ethanol, washed and dried to obtain the low-temperature-resistant and flame-retardant brominated SIS thermoplastic elastomer, the test performance is shown in Table 1.

[0134] Comparative Example 1

[0135] (1) Preparation of the macromolecular polar brominated ring-opening agent: the other conditions were the same as those in Example 1, except that the amount of 4-vinylbenzoic acid added in the preparation of the macromolecular polar brominated ring-opening agent was 8.0g, namely: in a 4L jacketed stainless steel reactor, inert gas was introduced to replace the air, 2000g cyclohexane, 300g cis-2-methyl-1,4-dibromo-2-butene and 252mmol THF were sequentially added into the polymerization kettle, the stirring speed was 500rpm, when the temperature was raised to 75°C, 252mmol n-butyllithium was added for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reached 100%, 200g diethyl allyl phosphate was then added into the polymerization kettle for further reaction, when the conversion rate of diethyl allyl phosphate monomer reached 97%, 8.0g 4-vinylbenzoic acid was added into the polymerization kettle for acidification reaction for 40min, after the reaction, the glue slurry was poured out, agglomerated, washed and vacuum dried to obtain the macromolecular polar brominated ring-opening agent a (Mn was 1960, Mw / Mn was 1.91).

[0136] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 1.

[0137] (III) Preparation of Low-Temperature Resistant and Flame-Retardant Brominated SIS Thermoplastic Elastomer: Other conditions are the same as in Example 1, except that no macromolecular polar brominated ring-opening agent is added during the preparation of the low-temperature resistant and flame-retardant brominated SIS thermoplastic elastomer. Instead, macromolecular polar brominated ring-opening agent a is added, with an addition amount of 1.0 mol. That is, 1 mol of epoxidized SIS thermoplastic elastomer is dissolved in xylene to prepare a 3.0 wt% epoxidized SIS thermoplastic elastomer solution, which is then added to the reaction vessel. The pH of the solution is adjusted to 1.0 with propionic anhydride. 1.0 mol of macromolecular polar brominated ring-opening agent a and 0.03 mol of ZrCl4 are added. The mixture is heated to 150°C and subjected to a ring-opening reaction for 5.0 hours. The resulting mixture is precipitated with ethanol, washed, and dried to obtain the low-temperature resistant and flame-retardant brominated SIS thermoplastic elastomer. The test performance is shown in Table 1.

[0138] Comparative Example 2

[0139] (I) Preparation of macromolecular polar brominated ring-opening agent: Other conditions are the same as in Example 2, except that cis-2-methyl-1,4-dibromo-2-butene is not added in the preparation of the macromolecular polar brominated ring-opening agent. Instead, 1,1-dibromoethylene is added in an amount of 310g. That is, in a 4L stainless steel reactor with a jacket, an inert gas is introduced for purging. 2100g of cyclohexane, 310g of 1,1-dibromoethylene and 274mmol of THF are added to the polymerization reactor in sequence. The stirring speed is 520rpm. When the temperature is raised to 77°C, 240mmol of n-butyllithium is added to react. When the conversion rate of 1,1-dibromoethylene monomer reaches 100%, 190g of allyl dipropyl phosphate is added to the polymerization reactor to continue the reaction. When the conversion rate of allyl dipropyl phosphate monomer reaches 97%, 18g of... 4-Vinylbenzoic acid was subjected to an acidification reaction for 43 min. After the reaction, the slurry was poured out, coagulated, washed, and vacuum dried to obtain a macromolecular polar brominated ring-opening agent b (Mn is 2190, Mw / Mn is 1.95).

[0140] (II) Preparation of epoxidized SIS thermoplastic elastomer: Same as in Example 2.

[0141] (Three) Preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer: other conditions are the same as example 2, the difference is that in the preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, no polar brominated macromolecular ring opening agent is added, but polar brominated macromolecular ring opening agent b is added, the amount is 1.12 mol, that is: 1 mol of epoxidized SIS thermoplastic elastomer is dissolved in xylene to prepare a 3.4wt% epoxidized SIS thermoplastic elastomer solution, which is added to the reaction kettle, when the pH of the solution is adjusted to 2.2 with butyric anhydride, 1.12 mol of polar brominated macromolecular ring opening agent b and 0.04 mol of ZrCl4 are added, and the reaction is carried out at 152℃ for 5.3 hours. The reaction mixture is precipitated with ethanol, washed and dried to obtain low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0142] Comparative example 3

[0143] (One) Preparation of polar brominated macromolecular ring opening agent: other conditions are the same as example 4, the difference is that in the preparation of polar brominated macromolecular ring opening agent, no allyl phosphoric acid dibutyl ester is added, but ethyl acrylate is added, the amount is 330g, that is: in a 4L stainless steel reactor with jacket, replace with inert gas, add 2300g of cyclohexane, 330g of cis-2-methyl-1,4-dibromo-2-butene and 290mmol of THF to the polymerization kettle, stir at a speed of 560rpm, heat to 81℃, then add 187mmol of n-butyllithium for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, then add 330g of ethyl acrylate to the polymerization kettle for further reaction, when the conversion rate of ethyl acrylate monomer reaches 97%, then add 22g of 4-vinylbenzoic acid to the polymerization kettle for acidification reaction for 47min, after reaction, pour out the glue slurry, wash and vacuum dry to obtain polar brominated macromolecular ring opening agent d (Mn is 2690, Mw / Mn is 2.08).

[0144] (Two) Preparation of epoxidized SIS thermoplastic elastomer: same as example 4.

[0145] (Three) Preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer: other conditions are the same as example 4, the difference is that in the preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, no macromolecular polar brominated ring opening agent is added, but macromolecular polar brominated ring opening agent d is added, the amount is 1.28 mol, that is: 1 mol of epoxidized SIS thermoplastic elastomer is dissolved in xylene to prepare a 4.3wt% epoxidized SIS thermoplastic elastomer solution, which is added to the reaction kettle, and when the pH of the solution is adjusted to 4.0 with hexanoic anhydride, 1.28 mol of macromolecular polar brominated ring opening agent d and 0.07 mol of ZrCl4 are added, and when heated to 156℃, the ring opening reaction is carried out for 5.7 hr, and the mixed solution after reaction is precipitated with ethanol, washed and dried to obtain low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, and the performance is tested as shown in Table 1.

[0146] Comparative example 4

[0147] (One) Preparation of macromolecular polar brominated ring opening agent: other conditions are the same as example 5, the difference is that no allyl phosphoric acid diethyl ester is added in the preparation of macromolecular polar brominated ring opening agent, that is: in a 4L stainless steel reactor with jacket, inert gas is introduced to replace, 2400g of cyclohexane, 340g of cis-2-methyl-1,4-dibromo-2-butene and 300mmol of THF are sequentially added to the polymerization kettle, the stirring speed is 590rpm, the temperature is raised to 83℃, 180mmol of n-butyllithium is added for reaction, when the conversion rate of cis-2-methyl-1,4-dibromo-2-butene monomer reaches 100%, 23g of 4-vinylbenzoic acid is added to the polymerization kettle for acidification reaction for 48min, after reaction, the gel is poured out, washed and vacuum dried to obtain macromolecular polar brominated ring opening agent e (Mn is 1800, Mw / Mn is 1.98).

[0148] (Two) Preparation of epoxidized SIS thermoplastic elastomer: same as example 5.

[0149] (III) Preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer: other conditions are the same as those in Example 5, except that in the preparation of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, no macromolecular polar brominated ring-opening agent is added, but a macromolecular polar brominated ring-opening agent e is added, and the amount of addition is 1.35 mol, i.e. 1 mol of epoxidized SIS thermoplastic elastomer is dissolved in xylene to prepare a 4.8 wt% epoxidized SIS thermoplastic elastomer solution which is added to a reaction kettle, propionic anhydride is used to adjust the pH of the solution to 4.8, 1.35 mol of macromolecular polar brominated ring-opening agent e and 0.08 mol of ZrCl4 are added, and when the temperature is heated to 158°C, the ring-opening reaction is carried out for 5.8 hours, the mixed solution after the reaction is precipitated with ethanol, washed and dried to obtain a low temperature resistant, flame retardant brominated SIS thermoplastic elastomer, and the test performance is shown in Table 1.

[0150] Table 1 Performance of low temperature resistant, flame retardant brominated SIS thermoplastic elastomer

[0151]

[0152]

[0153] As shown in Table 1, compared with Examples 1-10 and Comparative Examples 1-4, the low temperature resistant, flame retardant brominated SIS thermoplastic elastomer prepared by the present application has a low glass transition temperature, a high -20°C breaking rate, a high peeling strength, a high oxygen index and a tensile strength change rate <10% after hot air aging at 100°C for 72h, and exhibits excellent low temperature resistance, high efficiency flame retardancy and stability.

[0154] Of course, the present application can also have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A method for preparing a low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer, characterized in that, Includes the following steps: Step 1 involves a block copolymerization reaction of cis-2-methyl-1,4-dibromo-2-butene and allyl phosphate diester, followed by an acidification reaction with the addition of 4-vinylbenzoic acid 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 a low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer. The mass ratio of cis-2-methyl-1,4-dibromo-2-butene, allyl phosphate diester, and 4-vinylbenzoic acid is (30-70):(30-40):(3.0-5.0).

2. The method for preparing the low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 1, characterized in that, Step 1 is as follows: the cis-2-methyl-1,4-dibromo-2-butene is subjected to a polymerization reaction. After the conversion rate of the cis-2-methyl-1,4-dibromo-2-butene monomer reaches 95%, allyl phosphate diester is added to carry out a polymerization reaction. After the conversion rate of the allyl phosphate diester monomer reaches 97%, 4-vinylbenzoic acid is added to carry out an acidification reaction to obtain a ring-opening agent.

3. The method for preparing the low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 2, characterized in that, The polymerization reaction of cis-2-methyl-1,4-dibromo-2-butene 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 cis-2-methyl-1,4-dibromo-2-butene, allyl phosphate diester, and 4-vinylbenzoic acid is (60-70):(30-40):(3.0-5.0); the molar ratio of the structure modifier to the initiator is (1.0-2.0):

1.

4. The method for preparing the low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The block copolymerization reaction is carried out at a temperature of 75–85°C, the acidification reaction is carried out at a temperature of 75–85°C, and the acidification reaction is carried out for a time of 40–50 min; the allyl phosphate diester is at least one of allyl dimethyl phosphate, allyl diethyl phosphate, allyl dipropyl phosphate, allyl dibutyl phosphate, allyl dipentyl phosphate, and allyl dihexyl phosphate.

5. The method for preparing the low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The ring-opening agent has the following structure: Formula I: Where R is a C1 to C6 straight-chain alkyl group; n and m are the number of repeating units, n≥1 and m≥1.

6. The method for preparing the low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 5, characterized in that, The ring-opening agent has a number-average molecular weight of 2000-3000 and a molecular weight distribution of 1.93-2.

26.

7. The method for preparing the low-temperature resistant, flame-retardant 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 low-temperature resistant, flame-retardant 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 (0.02-0.5):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 low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The epoxy degree of the epoxidized SIS is 5% to 8%.

10. The method for preparing the low-temperature resistant, flame-retardant 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 (0.01-0.2):1; the molar ratio of the ring-opening agent to the epoxy group in the epoxidized SIS is (1.0-1.4):

1.

11. The method for preparing the low-temperature resistant, flame-retardant 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:(100-140):(3-9).

12. The method for preparing the low-temperature resistant, flame-retardant 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 low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer according to claim 1, characterized in that, The ring-opening reaction temperature is 150–160°C, and the ring-opening reaction time is 5.0–6.0 hr.

14. The low-temperature resistant, flame-retardant brominated SIS thermoplastic elastomer obtained by the preparation method according to any one of claims 1-13.

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