An amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin and its preparation method

Abstract

This invention provides an amino-functionalized transparent impact-resistant isophthalic resin and its preparation method, belonging to the field of functional polymer material synthesis. The amino-functionalized transparent impact-resistant isophthalic resin is a multi-component copolymer of styrene, isoprene, and a p-chloromethylstyrene derivative monomer containing tertiary amine functional groups. The preparation method employs a classic anionic polymerization method. First, an amino-functionalized polystyrene active segment SN1 is prepared. Then, it is added to a styrene / isoprene mixed monomer for a two-stage reaction to obtain a block copolymer segment SN1-SP with alternating styrene / isoprene sequences. Finally, styrene and the amino-functionalized monomer are added for a three-stage reaction or directly coupled with a coupling agent to obtain a special block copolymer SN1-SP-SN2, successfully yielding the amino-functionalized transparent impact-resistant isophthalic resin. By controlling the length of the special alternating sequence molecular chain and the block composition ratio, the mechanical properties of the product are controlled. Simultaneously, the tertiary amine polar groups are quantitatively introduced into the molecular chains, successfully achieving high impact resistance and transparency, and also enhancing the resin polarity. Using a lithium-based polymerization method, the resin particles are free of monomer and harmful impurities.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer materials technology, and relates to an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin and its preparation method. Background Technology

[0002] Styrene-based transparent impact-resistant resins are a class of special block copolymers of styrene / conjugated dienes. Due to their excellent transparency and impact resistance, they are commonly used in packaging products, pharmaceutical and hygiene products, children's toys, electrical appliances, and coatings for high-grade glossy papers. The properties of polymer materials are closely related to their structure. The mechanical strength of styrene-butadiene resin depends on the pure polystyrene blocks, its toughness is heavily dependent on the sequence structure type of styrene and diene, and its transparency is mainly affected by the refractive index and phase separation structure of the styrene blocks and the intermediate styrene / diene copolymer sequence blocks. Furthermore, the specific molecular weight and distribution, block ratio, and copolymer composition of the styrene-based transparent impact-resistant resin base directly affect the comprehensive physicochemical properties of the transparent impact-resistant resin. Several styrene-based transparent impact-resistant resin series exist internationally (mainly styrene-butadiene series), such as Phillips' K-resin, the German "Styrolux" series, and the Japanese "Asaflex" series. New transparent impact-resistant resin manufacturers are constantly emerging, continuously expanding the application areas of new transparent impact-resistant resins. Currently, there are no reports domestically or internationally regarding the use of isoprene in styrene-based transparent impact-resistant resins.

[0003] Anionic polymerization is widely used to synthesize transparent, impact-resistant styrene resins due to its unique advantages, including controllable molecular weight, extremely narrow molecular weight distribution, diverse sequence regulation methods, and precise microstructure control. Generally, styrene and butadiene are used as comonomers to synthesize styrene-butadiene resins. This type of product possesses excellent properties such as transparency and impact resistance, but its non-polar nature leads to poor compatibility with polar materials. Furthermore, polymer functionalization is typically divided into in-situ polymerization functionalization and post-polymerization functionalization. Compared to post-polymerization functionalization, in-situ polymerization functionalization allows for "in-situ" site-specific and quantitative modification, resulting in simpler production processes and more controllable costs. The introduction of tertiary amine functional groups can significantly improve resin polarity, which is beneficial for further expanding the application areas of the product. However, the number of monomers suitable for lithium-based anionic polymerization is currently limited, requiring structural design of monomers containing these functional groups to adapt to reactive anionic polymerization methods. Polar styrene derivatives possess relatively good polymerization activity, strong functional group designability, and relatively inexpensive and readily available raw materials, making them an excellent class of functionalized monomers. Polar functionalized monomers suitable for modifying styrene resins can be directly obtained through the substitution reaction of chloromethylstyrene monomers with secondary amines. Compared with other polar monomers, these monomers have the following characteristics: simple preparation process and high cost-effectiveness; minimal impact on styrene / diene activity and mild reaction conditions; diverse functional groups, including linear aliphatic amines and cyclic amine substitution products; negligible probability of side reactions; and precise control of the degree of polar modification through the feeding method and dosage. Research revealed that no patents in China have been published regarding the use of such monomers for the polar modification of styrene resins.

[0004] Dalian University of Technology patent CN201910299802.X discloses a method for preparing an amino-functionalized styrene-butadiene resin. It is prepared by copolymerizing butadiene, styrene, and amino-functionalized diphenylethylene derivatives initiated by alkyl lithium. The copolymer chain contains at least two amino-functionalized diphenylethylene derivative units; the styrene mass percentage is 45%-90%, the butadiene mass percentage is 5%-50%, and the remainder is amino-functionalized diphenylethylene derivatives. This modified amino-functionalization strategy can improve the thermal properties of transparent impact-resistant styrene-butadiene resin and its compatibility with other polar polymers, facilitating the preparation of high-performance transparent impact-resistant styrene-butadiene resin and its composites. While a polarized DPE monomer copolymerization strategy can improve the polarity and heat resistance of styrene-butadiene resin, allowing for quantitative and targeted insertion into the polymer chain, the preparation cost of the polarized DPE monomer is relatively high, and excessive addition will reduce the conversion rate of other monomers to some extent.

[0005] Guangdong Zhonghe High-Tech Patent CN202111611191.1 provides a transparent, impact-resistant styrene-butadiene resin, its preparation method, and its applications. First, active polystyrene segments are prepared. Then, the active polystyrene segments, a random copolymerization regulator, styrene monomer, and butadiene monomer are reacted to obtain styrene / butadiene random copolymer segments. These segments are then end-capped to obtain vinyl-containing styrene / butadiene block copolymer segments. Finally, the vinyl-containing styrene / butadiene block copolymer segments are deactivated and ring-opened with an epoxy monomer to successfully obtain a polarized, transparent, impact-resistant styrene-butadiene resin. This preparation method, by adjusting the side chain content in the molecular chain segments and introducing polar groups into the molecular chain, successfully improves the polarity of the styrene-butadiene resin, thereby giving it good compatibility with polar materials and ultimately producing a transparent material with excellent impact resistance. This polarization process involves the use of deactivating agents and the precipitation of polyepoxy monomers in nonpolar solvents, and the process is relatively lengthy. Summary of the Invention

[0006] To address the problems existing in the prior art, the first objective of this invention is to provide a novel transparent and impact-resistant styrene-isoprene copolymer resin. This resin has the characteristics of high transparency and high toughness, and has great potential for application in fields such as medical devices, high-end food packaging, and polymer toughening additives.

[0007] The second objective of this invention is to provide a method for in-situ modification of transparent styrene-based impact-resistant resins by functionalizing monomers with tertiary amines, which is simple to operate and has controllable production costs.

[0008] To achieve the above-mentioned technical objectives, the present invention provides an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin and its preparation method, characterized in that it has the following special block structure SN1-SP-SN2; wherein SN1 and SN2 are styrene-amino-functionalized monomer copolymer polarization blocks; SP is an alternating copolymerization block of styrene and isoprene; and the mass percentage content of amino-functionalized monomers in the SN polarization block copolymer is less than 5%.

[0009]

[0010] As a preferred embodiment, the copolymer resin contains 65-95% styrene units and 35-5% isoprene units by mass percentage.

[0011] As a preferred embodiment, the amine functionalized monomer in the copolymer resin is selected from at least one or more of the following aliphatic or aromatic primary amine-substituted benzyl ethylenes: p-dimethylaminomethylstyrene, p-diethylaminomethylstyrene, p-diethylaminomethylstyrene, p-di-n-propylaminomethylstyrene, p-diisopropylaminomethylstyrene, p-dibutylaminomethylstyrene, p-dipentaminomethylstyrene, p-dihexylaminomethylstyrene, p-pyrrolidinylmethylstyrene, p-piperidinylmethylstyrene, p-(o-methyl)piperidinylmethylstyrene, p-(m-methyl)piperidinylmethylstyrene, p-(p-methyl)piperidinylmethylstyrene, p-morpholinylmethylstyrene, p-(p-methyl)piperazinylmethylstyrene, p-dibenzylaminomethylstyrene, and p-carbazoleylmethylstyrene.

[0012] As a preferred option, the number-average molecular weight of the SN1 and SN2 segments is 10,000 to 50,000; the number-average molecular weight of the SP segment is 50,000 to 150,000.

[0013] This invention provides a method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin, characterized in that: in an anionic polymerization solution system, styrene and amino-functionalized monomers are first added, followed by the addition of polar additives and initiators to carry out a first-stage initiation polymerization I, then the addition of styrene / isoprene mixed monomers to carry out a second-stage alternating copolymerization II, and finally the addition of styrene and amino-functionalized monomers to carry out a third-stage polymerization III, or a coupling agent is added directly after the second-stage polymerization to carry out a coupling reaction, ultimately preparing an SN1-SP-SN2 special triblock copolymer.

[0014] As a preferred embodiment, the anionic polymerization solution system uses at least one of cyclopentane, cyclohexane, benzene, and toluene as a solvent. The preferred solvents are cyclopentane and / or cyclohexane. The amount of solvent used is sufficient to ensure that the mass percentage concentration of the monomer in the solvent is approximately 15%.

[0015] As a preferred embodiment, the initiator is an organolithium compound. Organolithium compounds include at least one of alkyllithium, aryllithium, aralkyllithium, and cycloalkyllithium. Most preferably, n-butyllithium and sec-butyllithium are used.

[0016] As a preferred embodiment, the polar additive is selected from one or a mixture of several oxygen-containing, nitrogen-containing, and phosphorus-containing polar compounds. Tetrahydrofuran is the most preferred.

[0017] As a preferred embodiment, the temperature of the first step reaction is 30–80°C and the time is 15–30 min; the temperature of the second step is further preferably 50–70°C.

[0018] As a preferred embodiment, the temperature of the second step reaction is 40-100℃ and the time is 25-60 min; the temperature of the second stage is further preferably 60-90℃.

[0019] As a preferred embodiment, the temperature of step III is 40–80°C and the time is 20–40 min; the temperature of step III is further preferably 60–80°C.

[0020] As a preferred embodiment, the coupling agent belongs to the polyhalogenated or polyepoxy functional group compounds, including polyepoxy compounds such as dichlorodimethylsilane, trichloromethylsilane, tetrachlorosilane, and soybean oil.

[0021] As a preferred embodiment, the coupling temperature is 40–90°C and the coupling time is 20–40 min; the coupling temperature is further preferably 50–70°C.

[0022] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0023] 1) The present invention provides an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin, which has a special multi-block structure. Its two ends are amino-functionalized modified styrene homopolymer blocks, and the middle is an alternating sequence of styrene and isoprene blocks. The polystyrene blocks tend to form physical cross-linking points to provide mechanical strength. The middle alternating sequence block diene mainly exists in the form of 1,4-structure (>90%). The special molecular structure endows it with high toughness. The two phases have similar refractive indexes, resulting in good transparency. The resin has good processability and film-forming properties. There are no monomer and modifier residues. It is particularly suitable for preparing medical machinery, high-end packaging materials and polymer toughening agents.

[0024] 2) In the preparation process of the amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin of the present invention, a small amount of isoprene is introduced and alternately copolymerized with some styrene monomers, effectively solving the problem of polystyrene's brittleness. At the same time, the isoprene chain structure is uniformly dispersed in the middle segment of the polymer chain, changing the phase separation structure of the traditional pure triblock copolymer, significantly increasing the volume of the middle soft segment phase, and greatly improving toughness. The molecular structure design solves the problem of balancing strength and toughness.

[0025] 3) The present invention provides an amine-functionalized transparent impact-resistant styrene-isoprene copolymer resin, which is modified by in-situ polymerization. A very small amount of amine functionalized monomers are introduced into the polystyrene chain segment. The polarity of the resin is controlled according to the amount of polar monomers. The production process is simple and easy to industrialize. Detailed Implementation

[0026] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. This patent analyzes the compositional sequence distribution and microstructure of copolymers using nuclear magnetic resonance spectroscopy, and analyzes the molecular weight and molecular weight distribution index (ratio of weight-average molecular weight to number-average molecular weight) of the copolymers using gel permeation chromatography. The physical properties of the samples are determined using an INSTRON-5565 electronic tensile testing machine, and the transmittance of the samples is determined using a DRTG-81 visible light transmittance meter.

[0027] Some of the monomers used in this invention are shown below:

[0028]

[0029] Example 1

[0030] A method for preparing an amino-functionalized transparent impact-resistant styrene-butadiene resin, the method comprising the following steps:

[0031] Designed with a SN:SP = 1:9 block ratio and a monomer concentration of 12%, 3500 mL of cyclopentane solution and 0.5 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. After the reactor was heated to 50–55 °C, 18 mL of styrene and 5 mL of VB-N1 were added, and stirring was started. Then, 6.0 mL of 0.5 mol / L n-butyllithium was added to carry out the first stage polymerization for 30 min. Next, 252 mL of styrene and 222 mL of isoprene mixed monomers were added to carry out the second stage alternating copolymerization reaction at 55 °C for 60 min. After the second stage copolymerization was completed, 23 mL of styrene was added to carry out the third stage polymerization at 50–60 °C for 25 min. A small amount of methanol was added to terminate the polymerization, and the solvent was removed and the product was then subjected to post-treatment to obtain the transparent impact-resistant isophthalic resin.

[0032] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 0.9% styrene-based polar monomer VB-N1, 63.2% styrene, 25.9% isoprene, 91.5% 1,4-polyisoprene, and 11% styrene blocks, with a number average molecular weight of 15.5 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.05. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 89.5%, a haze of 7.0, a flexural strength of 0.5 MPa, a yield strength of 15.6 MPa, and a Charpy impact strength of 98.6 J / m.

[0033] Example 2

[0034] Designed with a block ratio of SN:SP = 2:8 and a monomer concentration of 12%, 3500 mL of cyclohexane solution and 0.4 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. After the reactor was heated to 50–55 °C, 46 mL of styrene was added, and stirring was started. Then, 6.5 mL of 0.5 mol / L n-butyllithium was added to carry out the first stage polymerization for 25 min. Next, 224 mL of styrene and 198 mL of isoprene mixed monomers were added to carry out the second stage alternating copolymerization reaction at 60 °C for 45 min. After the second stage copolymerization was completed, 18 mL of styrene and 5 mL of VB-N2 monomer were added to carry out the third stage polymerization at 55–60 °C for 30 min. After terminating the polymerization with a small amount of methanol, the solvent was removed and the resulting transparent impact-resistant isophthalic resin was obtained.

[0035] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 1.0% styrene-based polar monomer VB-N2, 66.8% styrene, 32.2% isoprene, 91.8% 1,4-polyisoprene, and 19% styrene blocks, with a number average molecular weight of 12.5 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.07. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 88.9%, a haze of 6.5, a flexural strength of 4.88 MPa, a yield strength of 18.8 MPa, and a Charpy impact strength of 103.6 J / m.

[0036] Example 3

[0037] Designed with a block ratio of SN:SP = 3:7 and a monomer concentration of 12%, 3500 mL of an equal volume mixed solution of cyclohexane / cyclopentane and 0.6 mL of tetrahydrofuran (THF) were added to a 5L polymerization reactor. After heating the reactor to 50–55°C, 67.5 mL of styrene and 2.5 mL of VB-N5 monomer were added, and stirring was started. Then, 5.0 mL of 0.5 mol / L n-butyllithium was added to carry out the first stage polymerization for 35 min. Next, 196 mL of styrene and 173 mL of isoprene mixed monomers were added to carry out the second stage alternating copolymerization reaction at 55°C for 50 min. After the second stage copolymerization was completed, 67.5 mL of styrene and 2.5 mL of VB-N5 monomer were added to carry out the third stage polymerization at 55–60°C for 30 min. After terminating the polymerization with a small amount of methanol, the solvent was removed and the resulting transparent impact-resistant isophthalic resin was obtained.

[0038] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 0.9% styrene-based polar monomer VB-N5, 70.5% styrene, 28.6% isoprene, 90.0% 1,4-polyisoprene, and 31.1% styrene blocks, with a number average molecular weight of 18.9 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.05. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 87.2%, a haze of 8.5, a flexural strength of 7.2 MPa, a yield strength of 19.9 MPa, and a Charpy impact strength of 113.3 J / m.

[0039] Example 4

[0040] Designed with a block ratio of SN:SP = 4:6 and a monomer concentration of 12%, 3500 mL of toluene solution and 0.5 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. After the reactor was heated to 50–55 °C, 90 mL of styrene and 2.5 mL of VB-N4 monomer were added, and stirring was started. Then, 6.0 mL of 0.5 mol / L n-butyllithium was added to carry out the first stage polymerization for 35 min. Next, 168 mL of styrene and 148 mL of isoprene mixed monomers were added to carry out the second stage alternating copolymerization reaction at 60 °C for 50 min. After the second stage copolymerization was completed, 93 mL of styrene was added to carry out the third stage polymerization at 60 °C for 30 min. A small amount of methanol was added to terminate the polymerization, and the solvent was removed and the resulting transparent impact-resistant isophthalic resin was obtained.

[0041] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 0.4% styrene-based polar monomer VB-N4, 74.9% styrene, 24.7% isoprene, 92.0% 1,4-polyisoprene, and 42.0% styrene blocks, with a number average molecular weight of 14.9 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.05. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 90.2%, a haze of 6.0, a flexural strength of 18.9 MPa, a yield strength of 23.5 MPa, and a Charpy impact strength of 124.3 J / m.

[0042] Example 5

[0043] Designed with a SN:SP = 5:5 block ratio and a monomer concentration of 12%, 3500 mL of toluene solution and 0.4 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. The reactor was heated to 50–55 °C, and 116 mL of styrene was added. Stirring was then started, followed by the addition of 6.0 mL of 0.5 mol / L n-butyllithium for stage I polymerization, which lasted for 30 min. Then, 140 mL of styrene and 124 mL of isoprene mixed monomers were added for stage II alternating copolymerization, which was carried out at 60 °C for 45 min. After stage II copolymerization, 110 mL of styrene and 6 mL of VB-N5 monomer were added for stage III polymerization at 50 °C for 40 min. A small amount of methanol was added to terminate the polymerization, and solvent removal was performed to obtain the transparent impact-resistant isophthalic resin.

[0044] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 1.2% styrene-based polar monomer VB-N5, 78.3% styrene, 20.5% isoprene, 91.0% 1,4-polyisoprene, and 49.2% styrene blocks, with a number average molecular weight of 16.1 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.09. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 88.5%, a haze of 7.0, a flexural strength of 23.3 MPa, a yield strength of 25.5 MPa, and a Charpy impact strength of 138.9 J / m.

[0045] Example 6

[0046] Designed with a block ratio of SN:SP = 6:4 and a monomer concentration of 15%, 3000 mL of toluene solution and 0.5 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. The reactor was heated to 50–55 °C, and 140 mL of styrene was added. Stirring was then started, followed by the addition of 5.0 mL of 0.5 mol / L n-butyllithium for stage I polymerization, which lasted for 30 min. Then, 112 mL of styrene and 100 mL of isoprene mixed monomers were added for stage II alternating copolymerization, which was carried out at 60 °C for 50 min. After stage II copolymerization, 138 mL of styrene and 2.5 mL of VB-N3 monomer were added for stage III polymerization at 50 °C for 40 min. A small amount of methanol was added to terminate the polymerization, and solvent removal was performed to obtain the transparent impact-resistant isophthalic resin.

[0047] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 0.4% styrene-based polar monomer VB-N3, 84.1% styrene, 15.5% isoprene, 91.8% 1,4-polyisoprene, and 61% styrene blocks, with a number average molecular weight of 19.5 × 10⁻⁶. 4g / mol, molecular weight distribution 1.06. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 90.5%, a haze of 7.2, a flexural strength of 30 MPa, a yield strength of 28.5 MPa, and a Charpy impact strength of 118.0 J / m.

[0048] Example 7

[0049] Designed with a block ratio of SN:SP = 7:3 and a monomer concentration of 15%, 3000 mL of cyclopentane solution and 0.25 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. The reactor was heated to 50–55 °C, and 163 mL of styrene was added. Stirring was then started, followed by the addition of 6.0 mL of 0.5 mol / L n-butyllithium for stage I polymerization, which lasted for 40 min. Then, 84 mL of styrene and 74 mL of isoprene mixed monomers were added for stage II alternating copolymerization, which was carried out at 60 °C for 40 min. After stage II copolymerization, 160 mL of styrene and 3 mL of VB-N6 monomer were added for stage III polymerization at 50 °C for 40 min. A small amount of methanol was added to terminate the polymerization, and solvent removal was performed to obtain the transparent impact-resistant isophthalic resin.

[0050] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 0.6% styrene-based polar monomer VB-N6, 88.8% styrene, 12.6% isoprene, 91.5% 1,4-polyisoprene, and 70.8% styrene blocks, with a number average molecular weight of 15.5 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.05. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 87.5%, a haze of 7.9, a flexural strength of 38 MPa, a yield strength of 32.5 MPa, and a Charpy impact strength of 88.5 J / m.

[0051] Example 8

[0052] Designed with a block ratio of SN:SP = 8:2 and a monomer concentration of 15%, 3000 mL of cyclohexane solution and 0.25 mL of tetrahydrofuran (THF) were added to a 5L polymerization reactor. The reactor was heated to 50–55°C, and 186 mL of styrene was added. Stirring was then started, followed by the addition of 6.0 mL of 0.5 mol / L n-butyllithium for stage I polymerization, which lasted for 40 min. Then, 56 mL of styrene and 49 mL of isoprene mixed monomers were added for stage II alternating copolymerization, which was carried out at 60°C for 40 min. After stage II copolymerization, 180 mL of styrene and 6 mL of VB-N3 monomer were added for stage III polymerization at 50°C for 40 min. A small amount of methanol was added to terminate the polymerization, and solvent removal was performed to obtain the transparent impact-resistant isophthalic resin.

[0053] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 1.2% styrene-based polar monomer VB-N3, 90.3% styrene, 8.5% isoprene, 91.9% 1,4-polyisoprene, and 78.8% styrene blocks, with a number average molecular weight of 15.5 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.08. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 88.5%, a haze of 7.5, a flexural strength of 45 MPa, a yield strength of 38.5 MPa, and a Charpy impact strength of 56.8 J / m.

[0054] Example 9

[0055] Designed according to a SN:SP = 5:5 block ratio, with a monomer concentration of 12%, 3500 mL of toluene solution and 0.4 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. The reactor was heated to 50–55 °C, and 226 mL of styrene and 6 mL of VB-N5 monomer were added. Stirring was started, followed by the addition of 12.0 mL of 0.5 mol / L n-butyllithium for stage I polymerization, which lasted for 30 min. Then, 140 mL of a mixture of styrene and 124 mL of isoprene monomers were added for stage II alternating copolymerization, which was carried out at 60 °C for 45 min. After stage II copolymerization, 3 mL of 1.0 mol / L dichlorodimethylsilane coupling agent was added, and the coupling reaction was carried out at 50 °C for 30 min. Finally, solvent removal and post-treatment processes were performed to obtain the transparent impact-resistant isophthalic resin.

[0056] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 1.1% styrene-based polar monomer VB-N5, 78.4% styrene, 20.5% isoprene, 91.2% 1,4-polyisoprene, and 50.5% styrene blocks, with a number average molecular weight of 18.1 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.48, coupling degree 1.8. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 87.9%, a haze of 8.0, a flexural strength of 21.3 MPa, a yield strength of 23.5 MPa, and a Charpy impact strength of 118.0 J / m.

[0057] Example 10

[0058] Designed according to a SN:SP = 5:5 block ratio, with a monomer concentration of 12%, 3500 mL of toluene solution and 0.4 mL of tetrahydrofuran (THF) were added to a 5 L polymerization reactor. The reactor was heated to 50–55 °C, and 226 mL of styrene and 6 mL of VB-N5 monomer were added. Stirring was started, followed by the addition of 24.0 mL of 0.5 mol / L n-butyllithium for stage I polymerization, which lasted for 30 min. Then, 140 mL of a mixture of styrene and 124 mL of isoprene monomers were added for stage II alternating copolymerization, which was carried out at 60 °C for 45 min. After stage II copolymerization, 3 mL of 1.0 mol / L silicon tetrachloride coupling agent was added, and the coupling reaction was carried out at 50 °C for 30 min. Finally, solvent removal and post-treatment processes were performed to obtain the transparent impact-resistant isophthalic resin.

[0059] The product structure analysis results are as follows: By mass fraction, the terpolymer contains 1.0% styrene-based polar monomer VB-N5, 79.0% styrene, 20.0% isoprene, 91.5% 1,4-polyisoprene, and 50.1% styrene blocks, with a number average molecular weight of 20.8 × 10⁻⁶. 4 g / mol, molecular weight distribution 1.78, coupling degree 3.5. Product properties: The transparent plastic of styrene-butadiene resin has a light transmittance of 90.9%, a haze of 7.0, a flexural strength of 26.3 MPa, a yield strength of 28.5 MPa, and a Charpy impact strength of 148.2 J / m.

[0060] The above-described embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. An amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin, characterized in that: It has the following special block structure SN1-SP-SN2; wherein, SN1 and SN2 are styrene-amine functionalized monomer copolymer polarization blocks; SP is a styrene and isoprene alternating copolymer block; the styrene-amine functionalized monomer copolymer polarization block contains less than 5% by mass; the copolymer resin contains 65-95% styrene units and 95% by mass. 35-5%, with the number-average molecular weight of the SN1 and SN2 segments being 10,000-50,000; and the number-average molecular weight of the SP segment being 50,000-150,000; the amino-functionalized monomer is selected from one or more of the following: p-dimethylaminomethylstyrene, p-diethylaminomethylstyrene, p-di-n-propylaminomethylstyrene, p-diisopropylaminomethylstyrene, p-dibutylaminomethylstyrene, p-dipentaminomethylstyrene, p-dihexylaminomethylstyrene, p-pyrrolidinylmethylstyrene, p-piperidinylmethylstyrene, p-(o-methyl)piperidinylmethylstyrene, p-(m-methyl)piperidinylmethylstyrene, p-(p-methyl)piperidinylmethylstyrene, p-morpholinylmethylstyrene, p-(p-methyl)piperazinylmethylstyrene, p-dibenzylaminomethylstyrene, and p-carbazoleylmethylstyrene.

2. The method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin according to claim 1, characterized in that: In an anionic polymerization solution system, styrene and amino-functionalized monomers are first added, followed by polar additives and initiators for a first-stage initiation polymerization I. Then, a styrene / isoprene mixed monomer is added for a second-stage alternating copolymerization II. Finally, styrene and amino-functionalized monomers are added for a third-stage polymerization III, or a coupling agent is added directly after the second-stage polymerization for a coupling reaction, ultimately preparing the SN1-SP-SN2 special triblock copolymer.

3. The method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin according to claim 2, characterized in that: The anionic polymerization solution system uses at least one of cyclopentane, cyclohexane, benzene, and toluene as the polymerization solvent.

4. The method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin according to claim 2, characterized in that: The initiator is an alkyl lithium.

5. The method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin according to claim 2, characterized in that, The polar additive is selected from one or a mixture of several compounds, including oxygen-containing, nitrogen-containing, and phosphorus-containing polar compounds.

6. The method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin according to claim 2, characterized in that: The polymerization I reaction is carried out at a temperature of 30–80°C for 15–30 min; the alternating copolymerization II reaction is carried out at a temperature of 40–100°C for 25–60 min; and the three-stage polymerization III reaction is carried out at a temperature of 40–80°C for 20–40 min.

7. The method for preparing an amino-functionalized transparent impact-resistant styrene-isoprene copolymer resin according to claim 2, characterized in that: The coupling reaction is carried out at a temperature of 50–70°C for a time of 20–40 min.

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