A soap-free emulsion of a styrene-conjugated diene copolymer, its preparation method and application

Abstract

This application discloses a soap-free emulsion of styrene-conjugated diene copolymer, its preparation method, and its application, belonging to the field of polymer emulsion preparation technology. It consists of latex particles of styrene-conjugated diene copolymer ionomers and water; the surface of the ionomers is grafted with side groups; the side groups are sulfonates and / or carboxylates; the preparation method of the soap-free emulsion includes: taking an organic solution of styrene-conjugated diene copolymer, after carboxylation and / or sulfonation reactions, neutralizing it with an alkali metal or alkaline earth metal solution to obtain an ionomer solution, mixing it with water to form a polymer emulsion, and then removing the organic solvent and part of the deionized water by vacuum distillation to obtain the soap-free emulsion. The emulsion is pure, consisting only of water and SBS / SIS ionomers, and the entire preparation process does not require the addition of emulsifiers. This not only eliminates the complex post-processing steps required to separate clean particles from the latex but also avoids the generation of large amounts of wastewater containing emulsifiers.

Description

Technical Field

[0001] This application relates to a soap-free emulsion of styrene-conjugated diene copolymer, its preparation method and application, belonging to the field of polymer emulsion preparation technology. Background Technology

[0002] Styrene-conjugated diene copolymers are produced by copolymerizing styrene with butadiene and isoprene. They have a wide range of applications. Among them, block copolymers (SBS, butadiene-styrene block copolymers) are the most produced, lowest-cost, and most widely used type of styrene-based thermoplastic elastomers (SBCs). Due to their dual properties of plastics and rubber, they are hailed as "third-generation synthetic rubber." SIS (styrene-isoprene-styrene block copolymers) are sister products of SBS. They were developed simultaneously by Phillips Oil Company and Shell Chemical Company in the 1960s and further developed in the 1970s. SBS / SIS are typically prepared by anionic polymerization using styrene and butadiene / isoprene as raw materials and alkyllithium as a catalyst. SBS / SIS materials exhibit excellent tensile strength, elasticity, and low dielectric properties, displaying low permanent deformation, good flexural and resilience, and high surface friction. They are widely used in rubber products, adhesives, coatings, and many other fields.

[0003] SBS / SIS products are in solid form and are typically prepared as thermoplastic elastomers through bulk processing. They can also be used as modifiers, fillers, or adhesives. They can be used in conjunction with resins, rubbers, and other materials to adjust properties such as viscosity, hardness, flexibility, adhesion, and flexural strength. Furthermore, SBS / SIS is suitable for producing hot-melt adhesives and sealants, exhibiting strong adhesion, non-toxicity, and environmental friendliness. Traditional solid SBS / SIS products face challenges in bulk applications, including poor compatibility with polar materials, uneven mixing, complex processes, and high energy consumption. In contrast, SBS / SIS emulsion products effectively address these shortcomings, offering significant advantages in energy consumption, environmental friendliness, ease of use, performance stability, and application areas. Currently, SBS / SIS emulsions are primarily prepared through emulsification. This method uses organic solvents, compounded emulsifiers, water, and other components to emulsify SBS under high shear force, ultimately yielding an SBS emulsion product. (Publication number: CN) Patent 112300654A discloses a water-based rubber polymer waterproof coating, wherein the water-based polymer composite emulsion is prepared from the following raw materials: linear SBS, linear SIS, SBR, rosin resin, softener, coupling agent, surfactant, ammonia, zinc acetate, and water; Patent CN1554700A discloses a method for preparing an SBS water emulsion, which first dissolves polarized SBS (SBSM) in an organic solvent; stirring at 3000-5000 r / m, slowly adding water containing emulsifier, defoamer, and electrolyte to obtain an O / W type emulsion; then increasing the stirring speed to 8000-1 Stirring at 0000 rpm for 30 minutes breaks the particles to below 1 μm; the solvent is removed under heating and reduced pressure to obtain a stable SBS aqueous emulsion. Patent CN111218008A discloses a method for preparing a high-solids-content SBS emulsion for emulsified asphalt, comprising the following steps: dissolving solid SBS in a low-boiling-point organic solvent and mixing thoroughly to obtain an SBS premix; adding a compound emulsifier to water to prepare an aqueous emulsion; subjecting the aqueous emulsion to low-speed shearing, then adding the SBS premix and stabilizer, performing high-speed shear emulsification, allowing it to stand, and then distilling under reduced pressure to recover the organic solvent, thus obtaining the high-solids-content SBS emulsion. Existing SBS emulsion preparation processes are complex and generally use large amounts of emulsifiers, which not only increases production costs but also adversely affects the stability and mechanical properties of the product. More importantly, emulsifiers are often difficult to completely remove after use, potentially causing environmental pollution and, when used in products that come into contact with the human body, posing a potential hazard to human immunity and health. Therefore, reducing or replacing the use of emulsifiers in the preparation of SBS emulsions to improve product performance and environmental friendliness is an important direction for future research. Summary of the Invention

[0004] To address the problems of complex preparation processes and the widespread use of large amounts of emulsifiers in existing styrene-conjugated diene copolymer emulsion products, primarily SBS / SIS, and their adverse effects on stability and mechanical properties, as well as potential environmental and human hazards, caused by these issues, this application provides a soap-free emulsion of styrene-conjugated diene copolymer, its preparation method, and its application. Using SBS and / or SIS as raw materials, carboxylated or sulfonated SBS and / or SIS are prepared in an organic solvent using thiol-olefin click chemistry. The resulting ionomer solution is then neutralized in an organic solvent using a solution of alkali metal or alkaline earth metal hydroxides. Water is added to obtain a colloidal solution, and finally, the organic solvent is removed by vacuum distillation to obtain the soap-free emulsion.

[0005] The technical solution adopted in this application is as follows:

[0006] A soap-free emulsion of a styrene-conjugated diene copolymer, composed of latex particles of styrene-conjugated diene copolymer ionomers and water;

[0007] The surface of the ionomer is grafted with side group groups;

[0008] The side group is a sulfonate and / or a carboxylate;

[0009] The method for preparing the soap-free emulsion includes: taking an organic solution of a styrene-conjugated diene copolymer, subjecting it to carboxylation and / or sulfonation reactions, neutralizing it with a solution of alkali metal or alkaline earth metal hydroxides to obtain an ionomer solution, mixing it with water to form a polymer emulsion, and then removing the organic solvent and part of the deionized water by vacuum distillation to obtain the soap-free emulsion.

[0010] This soap-free emulsion has the following notable characteristics: the emulsion is pure and consists only of water and styrene-conjugated diene copolymer ionomers.

[0011] Optionally, the side group is selected from at least one of sodium carboxylate, potassium carboxylate, lithium carboxylate, calcium carboxylate, magnesium carboxylate, sodium sulfonate, potassium sulfonate, lithium sulfonate, calcium sulfonate, and magnesium sulfonate.

[0012] Optionally, the side group is selected from at least one of sodium carboxylate and potassium carboxylate.

[0013] Optionally, the styrene-conjugated diene copolymer is selected from styrene-butadiene-styrene block copolymers and / or styrene-isoprene-styrene block copolymers;

[0014] Optionally, the molecular weight of the styrene-conjugated diene copolymer is 50,000 to 260,000.

[0015] Optionally, the molecular weight of the styrene-conjugated diene copolymer is 60,000 to 130,000.

[0016] Optionally, the molecular weight of the styrene-conjugated diene copolymer is 60,000 to 100,000.

[0017] Optionally, the styrene content in the styrene-conjugated diene copolymer is 15wt% to 45wt%.

[0018] Optionally, the styrene content in the styrene-conjugated diene copolymer is 15wt% to 35wt%.

[0019] Optionally, the polybutadiene content in the styrene-butadiene-styrene block copolymer is 8 wt% to 75 wt%.

[0020] Optionally, the polybutadiene content in the styrene-butadiene-styrene block copolymer is 20wt% to 75wt%.

[0021] Optionally, the polyisoprene content in the styrene-isoprene-styrene block copolymer is 8 wt% to 75 wt%.

[0022] Optionally, the polyisoprene content in the styrene-isoprene-styrene block copolymer is 20wt% to 75wt%.

[0023] Optionally, the solid content of the soap-free emulsion is 1 wt% to 60 wt%.

[0024] Optionally, the solid content of the soap-free emulsion is selected from any value of 1wt%, 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, or any range between the two.

[0025] Optionally, the latex particles in the soap-free emulsion have a particle size of 50 nm to 2000 nm.

[0026] Optionally, the clustering index (PDI) is 0.03 to 0.4.

[0027] A smaller PDI value indicates a more uniform particle size distribution; conversely, a larger PDI value indicates a more uneven particle size distribution. The PDI mentioned below is also referred to as the PDI (Particle Size Index).

[0028] Optionally, the content of side group groups in the ionomer is 1 wt% to 15 wt%.

[0029] Optionally, the content of side group groups in the ionomer is 1 wt% to 10 wt%.

[0030] According to another aspect of this application, a method for preparing a soap-free emulsion of the above-mentioned styrene-conjugated diene copolymer is provided, comprising the following steps:

[0031] S1. In an inactive atmosphere, a styrene-conjugated diene copolymer is mixed with an organic solvent to obtain a polymer solution;

[0032] S2. Add a thiol, peroxide or azo compound containing a carboxyl or sulfonic acid group to the polymer solution in step S1, and heat to react to obtain a carboxylated and / or sulfonic acid-modified styrene-conjugated diene copolymer solution.

[0033] S3. Add the solution of alkali metal or alkaline earth metal hydroxide dropwise to the carboxylated and / or sulfonated styrene-conjugated diene copolymer solution in step S2, and neutralize it to obtain an ionomer solution.

[0034] S4. Mix the ionomer solution from step S3 with water to obtain a polymer emulsion;

[0035] The mixing conditions include adding the ionomer solution to water or adding water to the ionomer solution at a rate of 0.01 mL / s to 10 mL / s.

[0036] S5. The polymer emulsion from step S4 is subjected to vacuum distillation to remove the organic solvent and some water, resulting in a soap-free emulsion of the styrene-conjugated diene copolymer.

[0037] Optionally, in step S1, the organic solvent is selected from at least one of tetrahydrofuran, cyclohexane, acetone, and dichloromethane. Tetrahydrofuran or cyclohexane is preferred.

[0038] Optionally, in step S1, the content of the styrene-conjugated diene copolymer in the polymer solution is 1 wt% to 50 wt%.

[0039] Optionally, in step S1, the molecular weight of the styrene-conjugated diene copolymer is 50,000 to 260,000.

[0040] Optionally, in step S1, the styrene content in the styrene-conjugated diene copolymer is 15wt% to 45wt%.

[0041] Optionally, in step S1, the styrene content in the styrene-conjugated diene copolymer is 15wt% to 35wt%.

[0042] Optionally, in step S1, the content of polybutadiene in the styrene-butadiene-styrene block copolymer is 8wt% to 75wt%.

[0043] Optionally, the polybutadiene content in the styrene-butadiene-styrene block copolymer is 20wt% to 75wt%.

[0044] Optionally, in step S1, the content of polyisoprene in the styrene-isoprene-styrene block copolymer is 8wt% to 75wt%.

[0045] Optionally, in step S1, the content of polyisoprene in the styrene-isoprene-styrene block copolymer is 20wt% to 75wt%.

[0046] Optionally, in step S1, the molecular weight of the styrene-conjugated diene copolymer is selected from any value of 50,000, 100,000, 150,000, 200,000, 250,000, or 260,000, or any value between the two.

[0047] Optionally, in step S2, the molar ratio of the styrene-conjugated diene copolymer to the organic solvent to the thiol containing carboxyl or sulfonic acid groups in the polymer solution is 10 to 100:1.

[0048] Optionally, in step S2, the molar ratio of the styrene-conjugated diene copolymer to the organic solvent to the peroxide or azo compound in the polymer solution is 60 to 120:1.

[0049] Optionally, in step S2, the conditions for the heating reaction include: a reaction temperature of 40–80°C and a reaction time of 1–8 hours.

[0050] Optionally, in step S2, the reaction temperature in the heating reaction conditions is selected from any value of 40℃, 50℃, 60℃, 70℃, 80℃ or any range between two.

[0051] Optionally, in step S2, the reaction time in the heating reaction conditions is selected from any value of 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h or any range between two.

[0052] Optionally, in step S2, the grafting rate of the carboxylated and / or sulfonated styrene-conjugated diene copolymer is 1 wt% to 15 wt%. The grafting rate is expressed as the ratio of the mass of the grafted portion in the styrene-conjugated diene copolymer after the reaction to the mass of the unmodified styrene-conjugated diene copolymer.

[0053] Optionally, in step S2, the grafting rate of the carboxylated and / or sulfonated styrene-conjugated diene copolymer is 1 wt% to 10 wt%.

[0054] Optionally, in step S2, the thiol containing a carboxyl or sulfonic acid group is selected from at least one of 3-mercaptopropionic acid, 2-mercaptoacetic acid, 2-mercaptoethanesulfonic acid, and 3-mercaptopropanesulfonic acid. Preferably, it is 3-mercaptopropionic acid or 3-mercaptopropanesulfonic acid.

[0055] Optionally, in step S2, the peroxide or azo compound is selected from at least one of dodecyl peroxide, cyclohexanone peroxide, benzoyl peroxide, azobisisobutyronitrile, and azobisisoheptanenitrile. Dodecyl peroxide is preferred.

[0056] Optionally, in step S2, when the styrene-conjugated diene copolymer is a styrene-butadiene-styrene block copolymer (SBS), the chemical reaction formula for the heating reaction process in step S2 is shown in Formula I:

[0057]

[0058] Optionally, in step S3, the molar ratio of the functional groups in the alkali metal or alkaline earth metal hydroxide to the carboxylated and / or sulfonated styrene-conjugated diene copolymer is 0.1 to 3:1.

[0059] Optionally, in step S3, the molar ratio of the functional groups in the alkali metal or alkaline earth metal hydroxide to the carboxylated and / or sulfonated styrene-conjugated diene copolymer is 0.5 to 2:1.

[0060] Optionally, in step S3, the concentration of the alkali metal or alkaline earth metal hydroxide solution is 0.00005 to 0.02 mol / mL.

[0061] Optionally, in step S3, the conditions for the neutralization reaction include: a reaction temperature of 40–80°C and a reaction time of 1–8 h.

[0062] Optionally, in step S3, the reaction temperature in the neutralization reaction conditions is selected from any value of 40℃, 50℃, 60℃, 70℃, 80℃, or any range between two of them.

[0063] Optionally, in step S3, the reaction time in the neutralization reaction conditions is selected from any value of 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h or any range between two.

[0064] Optionally, in step S3, the alkali metal or alkaline earth metal hydroxide is selected from at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide. Sodium hydroxide and potassium hydroxide are preferred.

[0065] Optionally, in step S3, when the styrene-conjugated diene copolymer is a styrene-butadiene-styrene block copolymer (SBS), the chemical reaction formula for the heating reaction process in step S3 is shown in Formula II:

[0066]

[0067] Optionally, in step S3, when the styrene-conjugated diene copolymer is selected from styrene-butadiene-styrene block copolymer and / or styrene-isoprene-styrene block copolymer, the ionomer in the ionomer solution can be any one of formulas II (a) to (d):

[0068]

[0069] Among them, (a) carboxylated SBS ionomer; (b) sulfonated SBS ionomer; (c) carboxylated SIS ionomer; (d) sulfonated SIS ionomer; where M represents a metal ion.

[0070] Optionally, in step S4, the weight ratio of the ionomer solution to water is 1:1 to 3.

[0071] Optionally, in step S4, the weight ratio of the ionomer solution to water is 1:1 to 2.

[0072] Optionally, in step S4, the mixing conditions further include: mixing at a temperature of 30–70°C, and then stabilizing at 50–60°C for 0.5–24 hours.

[0073] Optionally, in step S4, the mixing conditions further include: mixing at a temperature of 50-60°C, and then stabilizing at 50-60°C for 1-8 hours.

[0074] Optionally, in step S4, the mixing conditions include: adding the ionomer solution to water or adding water to the ionomer solution at a rate of 0.05 mL / s to 5 mL / s.

[0075] Optionally, in step S4, the addition can be done by dripping or slowly pouring.

[0076] Optionally, in step S4, the mixing conditions may further include stirring, wherein the stirring method is selected from magnetic stirring, mechanical stirring, or high-speed stirring.

[0077] Optionally, in step S5, the conditions for vacuum distillation include: stirring, distillation temperature of 30℃~100℃, and solvent removal rate of 0.001mL / s~20mL / s.

[0078] Optionally, in step S5, the distillation temperature during vacuum distillation is 50℃~100℃.

[0079] Optionally, in step S5, the solvent removal rate under reduced pressure distillation conditions is 0.01 mL / s to 0.1 mL / s.

[0080] Optionally, in step S5, the stirring method during vacuum distillation can be selected from magnetic stirring, mechanical stirring, or high-speed stirring.

[0081] Optionally, in step S5, the conditions for vacuum distillation include: removing the organic solvent and part of the water by vacuum distillation until the organic solvent content in the polymer emulsion is less than 0.5 wt%.

[0082] According to another aspect of this application, a soap-free emulsion of the above-mentioned styrene-conjugated diene copolymer is also provided, and the application of the soap-free emulsion of the styrene-conjugated diene copolymer prepared according to any of the above preparation methods in the preparation of rubber products, adhesives, and coatings is also provided.

[0083] The beneficial effects that this application can produce include:

[0084] The soap-free emulsion of styrene-conjugated diene copolymer provided in this application has advantages such as high solid content, no surfactant, wide range of particle size control and narrow particle size distribution. Moreover, the latex film prepared by the self-assembly of polystyrene (PS) segments and polybutadiene (PB) segments and the crosslinking sites generated by ion clusters reduces the phase separation of the latex film, thereby improving tensile strength while retaining a high elongation at break.

[0085] The method for preparing soap-free emulsions of styrene-conjugated diene copolymers provided in this application eliminates the need for emulsifiers throughout the entire preparation process. This not only avoids the complex post-processing steps required to separate clean particles from the latex but also prevents the generation of large amounts of emulsifier-containing wastewater, which is crucial for environmental friendliness. Furthermore, the preparation of soap-free emulsions using SBS and / or SIS ionomers not only retains their excellent microphase separation structure but also introduces an ionic crosslinking network constructed from carboxylates. This dual crosslinking network significantly improves the mechanical properties of SBS and / or SIS as TPE materials and their compatibility with polar materials. Attached Figure Description

[0086] Figure 1 The images show the internal phase separation of the latex membrane made from the soap-free emulsion of this application, with (a) a size of 200 nm and (b) a size of 50 nm.

[0087] Figure 2The stress-strain curves of the latex films made from the soap-free emulsion of this application are shown in Example 18 (a), Example 19 (b), Example 20 (c), and Example 21 (d). In these examples, SBS-g-COOH·THF is a latex film made by casting a THF solution of carboxylated SBS; SBS-g-COOH / Na·THF is a latex film made by casting a THF solution of SBS ionomer; and SBS-g-COOH / Na·H2O is a latex film made by casting a soap-free latex emulsion of SBS ionomer. Detailed Implementation

[0088] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0089] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0090] The styrene-butadiene-styrene block copolymers used in the examples are labeled as SBS1 to SBS7 according to the different contents of PS and PB, and the styrene-isoprene-styrene block copolymers are labeled as SIS1 to SIS7 according to the different contents of PS and PI.

[0091] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0092] Performance evaluation of the emulsion: The average particle size, aggregation index and zeta potential of the emulsion were characterized by a laser nanoparticle size analyzer (DLS); the particle size and morphology of the emulsion particles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM); and the mechanical properties of the latex film formed at room temperature were characterized by a universal testing machine, a small angle scattering laser (SAXS) instrument and TEM.

[0093] Example 1

[0094] (1) Prepare a 1% (ω) THF solution by adding 1g of SBS1 and 99g of tetrahydrofuran (THF) to a 250mL three-necked flask. Purge the solution three times, then purge with nitrogen and stir to dissolve. The SBS1:Mn = 50,000, ω -PS =20%, ω -1，2PB =50%.

[0095] (2) Add 0.0090 g mercaptopropionic acid and 0.0001 g benzoyl peroxide to the SBS1 THF solution prepared in step (1), and react at 60 °C for 2.5 h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 1%.

[0096] (3) Prepare 1 mL of 0.000095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SBS1 ionomer solution.

[0097] (4) Under mechanical stirring (500 rpm) with a normal stirrer, the SBS1 ionomer solution from step (3) is added dropwise to water at 60°C (the mass ratio of water to SBS1 ionomer solution is 2:1). After stabilizing at 60°C for 3 hours, a mixed solution of SBS1 ionomer is obtained.

[0098] (5) The mixed solution of SBS1 ionomers from step (4) is distilled under reduced pressure at 60°C at a rate of 0.1 mL / s. The distilled organic solvent and some water are collected through a condenser until the organic solvent content in the solution is less than 0.5 wt%, thus obtaining a soap-free SBS1 emulsion.

[0099] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 301.4 nm, the PDI was 0.073, the Zeta potential was -52.7 mV, and the solid content was 1.53 wt%.

[0100] Example 2

[0101] Step (1) is the same as in Example 1.

[0102] (2) Add 0.090 g mercaptopropionic acid and 0.001 g benzoyl peroxide to the SBS1 THF solution prepared in step (1), and react at 60 °C for 2.5 h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 10%.

[0103] (3) Prepare 1 mL of 0.00095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SBS1 ionomer solution.

[0104] Steps (4) and (5) are the same as in Example 1, and SBS1 soap-free emulsion is obtained.

[0105] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 244.5 nm, the PDI was 0.054, the Zeta potential was -55.4 mV, and the solid content was 2.14 wt%.

[0106] Example 3

[0107] (1) Add 20g of SBS1 and 80g of tetrahydrofuran (THF) to a 250mL three-necked flask to prepare a THF solution with ω=20%, and purge three times. After purging with nitrogen, stir to dissolve.

[0108] (2) Add 0.5400g mercaptopropionic acid and 0.0043g benzoyl peroxide to the SBS1 THF solution prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 3%.

[0109] (3) Prepare 1 mL of 0.0057 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0110] Steps (4) and (5) are the same as in Example 1, and SBS1 soap-free emulsion is obtained.

[0111] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 277.1 nm, the PDI was 0.138, and the Zeta potential was -53.4 mV; the solid content was 24.79 wt%. An appropriate amount of SBS1 soap-free emulsion was poured into a polytetrafluoroethylene mold, dried at room temperature to constant weight, and its mechanical properties were measured. The tensile strength was 39.6 MPa, and the elongation at break was 1324.5%.

[0112] Example 4

[0113] Step (1) is the same as in Example 3.

[0114] (2) Add 1.8000g mercaptopropionic acid and 0.0086g benzoyl peroxide to the SBS1 THF solution prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 10%.

[0115] (3) Prepare 1 ml of 0.019 mol / mL sodium hydroxide aqueous solution. Add the sodium hydroxide solution to the carboxylated SBS1 solution in step (2) at 60 °C. After stabilizing for 3 h, the SBS1 ionomer solution is obtained.

[0116] Steps (4) and (5) are the same as in Example 1, resulting in SBS1 soap-free emulsion.

[0117] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 208.6 nm, the PDI was 0.177, the Zeta potential was -56.7 mV, the solid content was 27.42 wt%, the tensile strength of the latex film was 47.5 MPa, and the elongation at break was 1175.2%.

[0118] Example 5

[0119] Step (1) is the same as in Example 3.

[0120] (2) Add 0.9000g mercaptopropionic acid and 0.0072g benzoyl peroxide to the SBS1 THF solution prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 5%.

[0121] (3) Prepare 2 mL of 0.0048 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0122] (4) Under mechanical stirring (500 rpm) with a normal stirrer, the SBS1 ionomer solution from step (3) is added dropwise to water at 60°C (the mass ratio of water to SBS1 ionomer solution is 2:1). After stabilizing at 60°C for 8 hours, a mixed solution of SBS1 ionomer is obtained.

[0123] Step (5) is the same as in Example 1, and SBS1 soap-free emulsion is obtained.

[0124] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 248.3 nm, the PDI was 0.196, the Zeta potential was -53.6 mV, the solid content was 26.86 wt%, the tensile strength of the latex film was 42.1 MPa, and the elongation at break was 1206.1%.

[0125] Example 6

[0126] Steps (1) and (2) are the same as in Example 5.

[0127] (3) Prepare 3 mL of 0.0032 mol / mL potassium hydroxide aqueous solution, add the potassium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0128] Steps (4) and (5) are the same as in Example 5, resulting in SBS1 soap-free emulsion.

[0129] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 287.4 nm, the PDI was 0.205, the Zeta potential was -52.3 mV, and the solid content was 29.45 wt%.

[0130] Example 7

[0131] Steps (1) and (2) are the same as in Example 5.

[0132] (3) Prepare 3 mL of 0.0032 mol / mL lithium hydroxide aqueous solution, add the lithium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0133] Steps (4) and (5) are the same as in Example 5, resulting in SBS1 soap-free emulsion.

[0134] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 95.2 nm, the PDI was 0.147, the Zeta potential was -54.7 mV, and the solid content was 24.52 wt%.

[0135] Example 8

[0136] Steps (1) and (2) are the same as in Example 5.

[0137] (3) Prepare 3 mL of 0.0032 mol / mL zinc hydroxide aqueous solution, add the zinc hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0138] Steps (4) and (5) are the same as in Example 5, resulting in SBS1 soap-free emulsion.

[0139] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles was 78.4 nm, the PDI was 0.187, the Zeta potential was -53.8 mV, and the solid content was 27.43 wt%.

[0140] Example 9

[0141] Steps (1) and (2) are the same as in Example 5.

[0142] (4) Prepare 3 mL of 0.0032 mol / mL magnesium hydroxide aqueous solution, add the magnesium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0143] Steps (4) and (5) are the same as in Example 5, resulting in SBS1 soap-free emulsion.

[0144] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 83.6 nm, the PDI was 0.174, the Zeta potential was -53.9 mV, and the solid content was 28.24 wt%.

[0145] Example 10

[0146] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS2, where SBS2: Mn = 50,000, ω -PS =15%, ω -1，2PB =50%, resulting in SBS2 soap-free emulsion.

[0147] The prepared SBS2 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 197.2 nm, the PDI was 0.243, the Zeta potential was -52.4 mV, and the solid content was 25.42 wt%.

[0148] Example 11

[0149] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS3, where SBS3: Mn = 50,000, ω -PS =35%, ω -1，2PB =50%, resulting in SBS3 soap-free emulsion.

[0150] The prepared SBS3 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 144.7 nm, the PDI was 0.154, the Zeta potential was -55.2 mV, and the solid content was 27.42 wt%.

[0151] Example 12

[0152] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS4, where SBS4: Mn = 50,000, ω -PS =35%, ω -1，2PB =20%, resulting in SBS4 soap-free emulsion.

[0153] The prepared SBS4 soap-free emulsion was characterized as follows: the average particle size of the latex particles was 278.5 nm, the PDI was 0.287, the Zeta potential was -52.3 mV, and the solid content was 26.49 wt%.

[0154] Example 13

[0155] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS5, where SBS5: Mn = 50,000, ω -PS =35%, ω -1，2PB =75%, resulting in SBS5 soap-free emulsion.

[0156] The prepared SBS5 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 166.4 nm, the PDI was 0.193, the Zeta potential was -53.2 mV, and the solid content was 27.52 wt%.

[0157] Example 14

[0158] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS6, where SBS6: Mn = 10,000, ω -PS =20, ω -1，2PB =50%, resulting in SBS6 soap-free emulsion.

[0159] The prepared SBS6 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 65.2 nm, the PDI was 0.108, the Zeta potential was -57.3 mV, and the solid content was 35.42 wt%.

[0160] Example 15

[0161] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS7, where SBS7: Mn = 100,000, ω -PS =20%, ω -1，2PB =50%, resulting in SBS7 soap-free emulsion.

[0162] The prepared SBS7 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 428.9 nm, the PDI was 0.269, the Zeta potential was -54.3 mV, and the solid content was 22.51 wt%.

[0163] Example 16

[0164] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SBS8, where SBS8: Mn = 150,000, ω -PS =40%, ω -1，2PB =60%, resulting in SBS8 soap-free emulsion.

[0165] The prepared SBS8 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 176.4 nm, the PDI was 0.159, the Zeta potential was -59.2 mV, and the solid content was 27.64 wt%.

[0166] Example 17

[0167] Steps (1) to (3) are the same as in Example 5.

[0168] (4) Under mechanical stirring (500 rpm) with a normal stirrer, water is added drop by drop at a rate of 2 mL / s to the SBS1 ionomer solution in step (3) at 60°C (the mass ratio of water to SBS1 ionomer solution is 2:1). After stabilizing at 60°C for 8 hours, a mixed solution of SBS1 ionomer is obtained.

[0169] Step (5) is the same as in Example 5, and SBS1 soap-free emulsion is obtained.

[0170] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles, measured by DLS, was 278.3 nm, the PDI was 0.234, and the Zeta potential was -51.7 mV; the solid content was 26.86 wt%. The tensile strength of the latex film was 43.1 MPa, and the elongation at break was 1246.3%.

[0171] Example 18

[0172] Steps (1) to (3) are the same as in Example 5.

[0173] (4) Under mechanical stirring (500 rpm) with a normal stirrer, the SBS1 ionomer solution from step (3) is added dropwise to water at 60°C (the mass ratio of water to SBS1 ionomer solution is 2:1). After stabilizing at 60°C for 8 hours, a mixed solution of SBS1 ionomer is obtained.

[0174] Step (5) is the same as in Example 5, and SBS1 soap-free emulsion is obtained.

[0175] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles, measured by DLS, was 217.4 nm, the PDI was 0.195, and the Zeta potential was -57.2 mV; the solid content was 29.43 wt%. The tensile strength of the latex film was 44.3 MPa, and the elongation at break was 1214.4%.

[0176] Example 19

[0177] Steps (1) and (2) are the same as in Example 18.

[0178] (3) Prepare 2 mL of 0.0024 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0179] Steps (4) and (5) are the same as in Example 18, resulting in SBS1 soap-free emulsion.

[0180] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 189.2 nm, the PDI was 0.242, the Zeta potential was -52.4 mV, the solid content was 27.24 wt%, the tensile strength of the latex film was 38.3 MPa, and the elongation at break was 1323.2%.

[0181] Example 20

[0182] Steps (1) and (2) are the same as in Example 18.

[0183] (3) Prepare 2 mL of 0.0036 mol / mL sodium hydroxide aqueous solution. Add the prepared sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C. After stabilizing for 8 h, the SBS1 ionomer solution is obtained.

[0184] Steps (4) and (5) are the same as in Example 18, resulting in SBS1 soap-free emulsion.

[0185] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 157.4 nm, the PDI was 0.284, the Zeta potential was -54.2 mV, the solid content was 25.37 wt%, the tensile strength of the latex film was 40.6 MPa, and the elongation at break was 1458.3%.

[0186] Example 21

[0187] Steps (1) and (2) are the same as in Example 18.

[0188] (3) Prepare 2 mL of 0.0060 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0189] Steps (4) and (5) are the same as in Example 18, resulting in SBS1 soap-free emulsion.

[0190] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 197.4 nm, the PDI was 0.177, the Zeta potential was -56.3 mV, the solid content was 27.47 wt%, the tensile strength of the latex film increased to 42.3 MPa, and the elongation at break was 1152.5%.

[0191] Example 22

[0192] Steps (1) and (2) are the same as in Example 18.

[0193] (3) Prepare 2 mL of 0.0095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0194] Steps (4) and (5) are the same as in Example 18, resulting in SBS1 soap-free emulsion.

[0195] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles, measured by DLS, was 187.4 nm, the PDI was 0.137, and the Zeta potential was -56.5 mV; the solid content was 28.34 wt%. The tensile strength of the latex film was 45.6 MPa, and the elongation at break was 1108.3%.

[0196] Example 23

[0197] (1) Add 50g of SBS1 and 50g of tetrahydrofuran (THF) to a 250mL three-necked flask to prepare a THF solution with ω=50%, and purge three times. After purging with nitrogen, stir to dissolve.

[0198] (2) Add 2.2500g mercaptopropionic acid and 0.0180g benzoyl peroxide to the SBS1 THF solution prepared in step (1), react at 60℃ for 2.5h, and determine the grafting rate after the reaction to be 5%.

[0199] (3) Prepare 2 mL of 0.012 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0200] Steps (4) and (5) are the same as in Example 18, resulting in SBS1 soap-free emulsion.

[0201] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 162.9 nm, the PDI was 0.223, the Zeta potential was -52.7 mV, and the solid content was 56.37 wt%.

[0202] Example 24

[0203] Step (1) is the same as in Example 23.

[0204] (2) Add 4.5000g mercaptopropionic acid and 0.0360g benzoyl peroxide to the SBS1 THF solution prepared in step (1), react at 60℃ for 2.5h, and determine that the grafting rate after the reaction is 10%.

[0205] (3) Prepare 3 mL of 0.016 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0206] Steps (4) and (5) are the same as in Example 18, resulting in SBS1 soap-free emulsion.

[0207] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 142.3 nm, the PDI was 0.174, the Zeta potential was -56.9 mV, and the solid content was 53.92 wt%.

[0208] Example 25

[0209] (1) Add 1g of SBS1 and 99g of cyclohexane to a 250mL three-necked flask to prepare a 1% cyclohexane solution. Purge the solution three times, purge with nitrogen, and stir to dissolve.

[0210] (2) Add 0.0090 g mercaptopropionic acid and 0.0001 g benzoyl peroxide to the cyclohexane solution of SBS1 prepared in step (1), and react at 60 °C for 2.5 h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 1%.

[0211] (3) Prepare 1 mL of 0.000095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SBS1 ionomer solution.

[0212] (4) Under the stirring of a high-speed stirrer (speed of 1500 rpm), the SBS1 ionomer solution from step (3) is added dropwise to water at 60°C (mass ratio of water to SBS1 ionomer solution is 1:1) at a speed of 2 mL / s. After stabilizing at 60°C for 1 h, a mixed solution of SBS1 ionomer is obtained.

[0213] (5) The mixed solution of SBS1 ionomers from step (4) is distilled under reduced pressure at 60°C at a rate of 0.1 mL / s. The distilled organic solvent and some water are collected through a condenser until the organic solvent content in the solution is less than 0.5 wt%, thus obtaining a soap-free SBS1 emulsion.

[0214] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 257.3 nm, the PDI was 0.065, the Zeta potential was -56.2 mV, and the solid content was 2.32 wt%.

[0215] Example 26

[0216] (1) Add 10g of SBS1 and 90g of cyclohexane to a 250mL three-necked flask to prepare a 10% cyclohexane solution. Purge the solution three times, purge with nitrogen, and stir to dissolve.

[0217] (2) Add 0.1800g mercaptopropionic acid and 0.0144g benzoyl peroxide to the SBS1 cyclohexane solution prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SBS1 solution. The grafting rate after the reaction was measured to be 10%.

[0218] (3) Prepare 1 mL of 0.0095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SBS1 ionomer solution.

[0219] Steps (4) and (5) are the same as in Example 25, resulting in SBS1 soap-free emulsion.

[0220] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 211.4 nm, the PDI was 0.072, the Zeta potential was -56.1 mV, and the solid content was 16.75 wt%.

[0221] Example 27

[0222] (1) Add 20g of SBS1 and 80g of cyclohexane to a 250mL three-necked flask to prepare a 20% cyclohexane solution. Purge the solution three times, purge with nitrogen, and stir to dissolve.

[0223] (2) Add 0.0900g mercaptopropionic acid and 0.0072g benzoyl peroxide to the SBS1 cyclohexane solution prepared in step (1), react at 60℃ for 2.5h, and determine the grafting rate after the reaction to be 5%.

[0224] (3) Prepare 1 mL of 0.0095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SBS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0225] Step (4) is the same as in Example 25, yielding a mixed solution of SBS1 ionomers.

[0226] (5) Distill the mixed solution of SBS1 ionomers from step (4) under reduced pressure at 60°C at a rate of 0.1 mL / s, and continuously add water to the solution at a rate of 0.1 mL / s. Receive the distilled organic solvent and some water through a condenser until the organic solvent content in the solution is less than 0.5 wt%, and obtain SBS1 soap-free emulsion.

[0227] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 189.3 nm, the PDI was 0.069, the Zeta potential was -56.3 mV, and the solid content was 24.79 wt%.

[0228] Example 28

[0229] Preparation steps (1) to (5) are the same as in Example 5, except that SBS1 is replaced with SIS1. The specific steps are as follows:

[0230] (1) Prepare a 1% THF solution by adding 1g of SIS1 and 99g of tetrahydrofuran (THF) to a 250mL three-necked flask, and then purging the solution three times with nitrogen gas and stirring to dissolve it. The molecular weight of SIS1 is Mn = 50,000, and ω... -PS =20%, ω -3，4PI =50%.

[0231] (2) Add 0.0090 g mercaptopropionic acid and 0.0001 g benzoyl peroxide to the THF solution of SIS1 prepared in step (1), and react at 60 °C for 2.5 h to obtain a carboxylated SIS1 solution. The grafting rate after the reaction was measured to be 1%.

[0232] (3) Prepare 1 mL of 0.000095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the reaction solution at 60℃, and react for 3 h to obtain SIS1 ionomer solution.

[0233] (4) Under the stirring of a normal stirrer (500 rpm), the SIS1 ionomer solution from step (3) is added dropwise to water at 60°C at a rate of 0.1 mL / s (the mass ratio of water to SIS1 ionomer solution is 1:1). After stabilizing at 60°C for 3 h, a mixed solution of SIS1 ionomer is obtained.

[0234] (5) Distill the mixed solution of SIS1 ionomers from step (4) under reduced pressure at a rate of 0.1 mL / s, and collect the distilled organic solvent and part of the water through a condenser until the organic solvent content in the solution is less than 0.5 wt%, to obtain SIS1 soap-free emulsion.

[0235] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles was 287.1 nm, the PDI was 0.095, the Zeta potential was -53.4 mV, and the solid content was 1.94 wt%.

[0236] Example 29

[0237] Step (1) is the same as in Example 28.

[0238] (2) Add 0.0900g mercaptopropionic acid and 0.0007g benzoyl peroxide to the THF solution of SIS1 prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SIS1 solution. The grafting rate after the reaction was measured to be 10%.

[0239] (3) Prepare 1 mL of 0.00095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SIS1 ionomer solution.

[0240] Steps (4) and (5) are the same as in Example 28, resulting in SBS1 soap-free emulsion.

[0241] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 217.4 nm, the PDI was 0.086, the Zeta potential was -52.1 mV, and the solid content was 2.32 wt%.

[0242] Example 30

[0243] (1) Add 20g of SIS1 and 80g of tetrahydrofuran (THF) to a 250mL three-necked flask to prepare a THF solution with ω=20%, and purge three times. After purging with nitrogen, stir to dissolve.

[0244] (2) Add 0.9000g mercaptopropionic acid and 0.0072g benzoyl peroxide to the THF solution of SIS1 prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SIS1 solution. The grafting rate after the reaction was measured to be 5%.

[0245] (3) Prepare 2 mL of 0.0048 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SIS1 ionomer solution.

[0246] (4) Under the stirring of a normal stirrer (500 rpm), the SIS1 ionomer solution from step (3) is added dropwise to water at 60°C at a rate of 0.1 mL / s (the mass ratio of water to SIS1 ionomer solution is 2:1). After stabilizing at 60°C for 3 h, a mixed solution of SBS1 ionomer is obtained.

[0247] Step (5) is the same as in Example 28, and SBS1 soap-free emulsion is obtained.

[0248] The prepared SBS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 188.2 nm, the PDI was 0.212, the Zeta potential was -54.3 mV, and the solid content was 27.86 wt%.

[0249] Example 31

[0250] Step (1) is the same as in Example 30.

[0251] (2) Add 0.5400g mercaptopropionic acid and 0.0043g benzoyl peroxide to the THF solution of SIS1 prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SIS1 solution. The grafting rate after the reaction was measured to be 10%.

[0252] (3) Prepare 2 mL of 0.0095 mol / mL sodium hydroxide aqueous solution, and add the sodium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C. After stabilizing for 8 h, the SIS1 ionomer solution is obtained.

[0253] Steps (4) and (5) are the same as in Example 28, and SIS1 soap-free emulsion is obtained.

[0254] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 165.2 nm, the PDI was 0.193, the Zeta potential was -55.2 mV, and the solid content was 28.54 wt%.

[0255] Example 32

[0256] Steps (1) to (5) are the same as in Example 31, except that SIS1 is replaced with SIS2, where SIS2: Mn = 50,000, ω -PS =15%, ω -3，4PI =50%, thus obtaining SIS2 soap-free emulsion.

[0257] The prepared SIS2 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 147.3 nm, the PDI was 0.215, the Zeta potential was -53.5 mV, and the solid content was 27.31 wt%.

[0258] Example 33

[0259] Steps (1) to (5) are the same as in Example 31, except that SIS1 is replaced with SIS3, where SIS3: Mn = 50,000, ω -PS =35%, ω -3，4PI =50%, thus obtaining SIS3 soap-free emulsion.

[0260] The prepared SIS3 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 223.4 nm, the PDI was 0.196, the Zeta potential was -54.9 mV, and the solid content was 27.26 wt%.

[0261] Example 34

[0262] Steps (1) to (5) are the same as in Example 31, except that SIS1 is replaced with SIS4, where SIS4: Mn = 50,000, ω -PS =20%, ω-3，4PI =20%, resulting in SIS4 soap-free emulsion.

[0263] The prepared SIS4 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 232.4 nm, the PDI was 0.168, the Zeta potential was -54.2 mV, and the solid content was 26.50 wt%.

[0264] Example 35

[0265] Steps (1) to (5) are the same as in Example 31, except that SIS1 is replaced with SIS5, where SIS5: Mn = 50,000, ω -PS =20%, ω -3，4PI =75%, thus obtaining SIS5 soap-free emulsion.

[0266] The prepared SIS5 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 293.4 nm, the PDI was 0.227, the Zeta potential was -53.9 mV, and the solid content was 26.86 wt%.

[0267] Example 36

[0268] Steps (1) to (5) are the same as in Example 31, except that SIS1 is replaced with SIS6, where SIS6: Mn = 10,000, ω -PS =20%, ω -3，4PI =50%, thus obtaining SIS6 soap-free emulsion.

[0269] The prepared SIS6 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 67.2 nm, the PDI was 0.076, the Zeta potential was -57.2 mV, and the solid content was 30.61 wt%.

[0270] Example 37

[0271] Steps (1) to (5) are the same as in Example 31, except that SIS1 is replaced with SIS7, where SIS7: Mn = 100,000, ω -PS =20%, ω -3，4PI =50%, thus obtaining SIS7 soap-free emulsion.

[0272] The prepared SIS7 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 334.5 nm, the PDI was 0.278, the Zeta potential was -56.2 mV, and the solid content was 23.57 wt%.

[0273] Example 38

[0274] Steps (1) and (2) are the same as in Example 31.

[0275] (3) Prepare 3 mL of 0.0064 mol / mL potassium hydroxide aqueous solution, add the potassium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SIS1 ionomer solution.

[0276] Steps (4) and (5) are the same as in Example 31, and SIS1 soap-free emulsion is obtained.

[0277] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 245.3 nm, the PDI was 0.205, the Zeta potential was -53.9 mV, and the solid content was 24.98 wt%.

[0278] Example 39

[0279] Steps (1) and (2) are the same as in Example 31.

[0280] (3) Prepare 3 mL of 0.0064 mol / mL lithium hydroxide aqueous solution, and add the lithium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C to obtain SIS1 ionomer solution.

[0281] Steps (4) and (5) are the same as in Example 31, and SIS1 soap-free emulsion is obtained.

[0282] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 87.4 nm, the PDI was 0.069, the Zeta potential was -58.6 mV, and the solid content was 29.52 wt%.

[0283] Example 40

[0284] Steps (1) and (2) are the same as in Example 31.

[0285] (3) Prepare 3 mL of 0.0064 mol / mL zinc hydroxide aqueous solution, add the zinc hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SIS1 ionomer solution.

[0286] Steps (4) and (5) are the same as in Example 31, and SIS1 soap-free emulsion is obtained.

[0287] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles was 132.4 nm, the PDI was 0.127, the Zeta potential was -57.2 mV, and the solid content was 27.82 wt%.

[0288] Example 41

[0289] Steps (1) and (2) are the same as in Example 31.

[0290] (3) Prepare 3 mL of 0.0064 mol / mL magnesium hydroxide aqueous solution, add the magnesium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SIS1 ionomer solution.

[0291] Steps (4) and (5) are the same as in Example 31, and SIS1 soap-free emulsion is obtained.

[0292] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 147.6 nm, the PDI was 0.155, the Zeta potential was -53.27 mV, and the solid content was 27.89 wt%.

[0293] Example 42

[0294] Step (1) is the same as in Example 31.

[0295] (2) Add 1.0638 g mercaptopropanesulfonic acid and 0.0084 g benzoyl peroxide to the SIS1 solution prepared in step (1), and react at 60 °C for 2.5 h to obtain sulfonic acid SIS1 solution. The grafting rate after the reaction was measured to be 10%.

[0296] (3) Prepare 3 mL of 0.0095 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the sulfonic acid group SIS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SIS1 ionomer solution.

[0297] Steps (4) and (5) are the same as in Example 31, and SIS1 soap-free emulsion is obtained.

[0298] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 192.4 nm, the PDI was 0.175, the Zeta potential was -56.82 mV, and the solid content was 27.98 wt%.

[0299] Example 43

[0300] (1) Add 50g of SIS1 and 50g of tetrahydrofuran (THF) to a 250mL three-necked flask to prepare a THF solution with ω=50%, and purge three times. After purging with nitrogen, stir to dissolve.

[0301] (2) Add 4.5000g mercaptopropionic acid and 0.0360g benzoyl peroxide to the THF solution of SIS1 prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SIS1 solution. The grafting rate after the reaction was measured to be 10%.

[0302] (3) Prepare 3 mL of 0.016 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SIS1 ionomer solution.

[0303] Steps (4) and (5) are the same as in Example 31, and SIS1 soap-free emulsion is obtained.

[0304] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 142.3 nm, the PDI was 0.241, the Zeta potential was -53.8 mV, and the solid content was 57.45 wt%.

[0305] Example 44

[0306] (1) Add 10g of SIS1 and 90g of cyclohexane to a 250mL three-necked flask to prepare a 10% cyclohexane solution. Then, purge the solution three times, purge with nitrogen, and stir to dissolve.

[0307] (2) Add 0.1800g mercaptopropionic acid and 0.0144g benzoyl peroxide to the cyclohexane solution of SIS1 prepared in step (1), and react at 60℃ for 2.5h to obtain a carboxylated SIS1 solution. The grafting rate after the reaction was measured to be 10%.

[0308] (3) Prepare 2 mL of 0.0048 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 8 h, obtain the SBS1 ionomer solution.

[0309] (4) While stirring with a high-speed stirrer (1500 rpm), slowly pour the SIS1 ionomer solution from step (3) into water at 60°C (the mass ratio of water to SIS1 ionomer solution is 1:1) at a speed of 2 mL / s. After stabilizing at 60°C for 1 h, a mixed solution of SIS1 ionomer is obtained.

[0310] (5) Distill the mixed solution of SIS1 ionomers from step (4) under reduced pressure at a rate of 0.1 mL / s, and collect the distilled organic solvent and part of the water through a condenser until the organic solvent content in the solution is less than 0.5 wt%, to obtain SIS1 soap-free emulsion.

[0311] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 293.4 nm, the PDI was 0.084, the Zeta potential was -52.6 mV, and the solid content was 13.64 wt%.

[0312] Example 45

[0313] (1) Add 10g of SIS1 and 90g of cyclohexane to a 250mL three-necked flask to prepare a 10% cyclohexane solution. Then, purge the solution three times, purge with nitrogen, and stir to dissolve.

[0314] (2) Add 0.1800g mercaptopropionic acid and 0.0144g benzoyl peroxide to the THF solution of SIS1 prepared in step (1), react at 60℃ for 2.5h, and determine that the grafting rate after the reaction is 10%.

[0315] (3) Prepare 2 mL of 0.0048 mol / mL sodium hydroxide aqueous solution, add the sodium hydroxide solution dropwise to the carboxylated SIS1 solution in step (2) at 60 °C, and after stabilizing for 3 h, obtain the SBS1 ionomer solution.

[0316] (4) Under the stirring of a high-speed stirrer (1500 rpm), the SIS1 ionomer solution from step (3) is added dropwise to water at 60°C at a rate of 0.1 mL / s (the mass ratio of water to SIS1 ionomer solution is 1:1). After stabilizing at 60°C for 1 h, a mixed solution of SIS1 ionomer is obtained.

[0317] (5) Distill the mixed solution of SIS1 ionomers from step (4) under reduced pressure at a rate of 0.1 mL / s and add water at a rate of 0.1 mL / s. Receive the distilled organic solvent and some water through a condenser until the organic solvent content in the solution is less than 0.5 wt% to obtain SIS1 soap-free emulsion.

[0318] The prepared SIS1 soap-free emulsion was characterized as follows: the average particle size of the latex particles measured by DLS was 246.3 nm, the PDI was 0.067, the Zeta potential was -56.2 mV, and the solid content was 16.75 wt%.

[0319] In summary, the characterization results of the soap-free emulsions prepared in Examples 1, 5, and 23 show that soap-free emulsions can be prepared when the content of styrene-conjugated diene copolymer in the polymer solution is 1wt% to 50wt%, with an average particle size of 162.9nm-301.4nm, a PDI of 0.073-0.223, a Zeta potential of -53.6mV to 52.7mV, and a solid content of 1.53wt%-56.37wt%. The characterization results of the soap-free emulsions prepared in Examples 1, 2, 28, and 29 show that soap-free emulsions can be prepared when the grafting rate of carboxylated and / or sulfonated styrene-conjugated diene copolymer is 1wt% to 10wt%, with an average particle size of 217.4nm. -301.4 nm, PDI of 0.054-0.073; As can be seen from the soap-free emulsions prepared in Examples 5 to 9 and Examples 37 to 41, soap-free emulsions can be prepared by neutralization with different alkali metal and alkaline earth metal hydroxides. The average particle size of the emulsion is 83.6 nm-224.5 nm, PDI is 0.069-0.278, and Zeta potential is -58.6 mV--52.3 mV; As can be seen from the characterization results of the soap-free emulsions prepared in Examples 18 to 21, soap-free emulsions can be prepared with different amounts of alkali metal hydroxides. The average particle size of the emulsion is 157.4 nm-217.4 nm, PDI is 0.177-0.284, the prepared emulsion can form a film at room temperature, and the dried latex film has excellent mechanical properties.

[0320] Taking Example 18 as an example, an appropriate amount of soap-free emulsion was slowly poured into a polytetrafluoroethylene mold and allowed to dry to constant weight at room temperature. The dried latex film was then frozen and sectioned (40-50 nm thick), stained with ethoxylate, and its microphase separation morphology was observed using a transmission electron microscope. Figure 1 As shown, in the phase separation within the self-assembled latex membrane, the PS phase is spherically dispersed within the PB phase, with a phase separation size of approximately 10 nm, smaller than that of the membranes prepared from SBS ionomer organic solutions and click-functionalized SBS organic solutions (20–30 nm). Therefore, the latex membrane exhibits superior mechanical properties. Using Examples 18–21 as typical examples, an appropriate amount of soap-free emulsion was slowly poured into a polytetrafluoroethylene mold and allowed to dry to constant weight at room temperature to obtain a latex membrane with a thickness of 1 mm. Samples were cut according to GB / T528-2009 standard, and stress-strain curve tests were performed. The results are as follows: Figure 2As shown, the film still exhibits high tensile strength (>40 MPa) at high elongation at break (1200%–1400%), which is greater than that of films made from carboxylated SBS cast with THF solution and films made from SBS ionomer cast with THF solution. This indicates that the film made from soap-free emulsion has a more ideal dual crosslinking network, thereby further improving the mechanical properties of styrene elastomer materials.

[0321] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A soap-free emulsion of a styrene-butadiene-styrene block copolymer, characterized in that, It is composed of latex particles of styrene-butadiene-styrene block copolymer ionomer and water; The surface of the ionomer is grafted with side group groups; The side group is a carboxylate; The method for preparing the soap-free emulsion includes the following steps: S1. In an inactive atmosphere, the styrene-butadiene-styrene block copolymer is mixed with an organic solvent to obtain a polymer solution; S2. Add a carboxyl-containing thiol, peroxide or azo compound to the polymer solution in step S1, and heat to react to obtain a carboxylated styrene-butadiene-styrene block copolymer solution. S3. Add the solution of alkali metal or alkaline earth metal hydroxide dropwise to the carboxylated styrene-butadiene-styrene block copolymer solution in step S2, and neutralize it to obtain an ionomer solution. S4. Mix the ionomer solution from step S3 with water to obtain a polymer emulsion; S5. The organic solvent and part of the deionized water are removed by vacuum distillation to obtain the soap-free emulsion; In the phase separation inside the film made from this soap-free emulsion, the PS phase is spherically dispersed in the PB phase.

2. The soap-free emulsion of styrene-butadiene-styrene block copolymer according to claim 1, characterized in that, The polybutadiene content in the styrene-butadiene-styrene block copolymer is 8wt%~75wt%.

3. The soap-free emulsion of the styrene-butadiene-styrene block copolymer according to claim 1, characterized in that, The solid content of the soap-free emulsion is 1 wt% to 60 wt%.

4. The soap-free emulsion of the styrene-butadiene-styrene block copolymer according to claim 1, characterized in that, The latex particles in the soap-free emulsion have a particle size of 50 nm to 2000 nm.

5. The soap-free emulsion of the styrene-butadiene-styrene block copolymer according to claim 1, characterized in that, The polymerization index (PDI) of the soap-free emulsion is 0.03 to 0.

4.

6. The soap-free emulsion of the styrene-butadiene-styrene block copolymer according to claim 1, characterized in that, The content of side groups in the ionomer is 1 wt% to 15 wt%.

7. A method for preparing a soap-free emulsion of the styrene-butadiene-styrene block copolymer according to any one of claims 1 to 6, characterized in that, The mixing conditions include: adding the ionomer solution to water or adding water to the ionomer solution at a rate of 0.01 mL / s to 10 mL / s, and using ordinary stirring and / or high-speed stirring, with a stirring speed of 100 rpm to 1000 rpm for ordinary stirring and 1000 rpm to 3000 rpm for high-speed stirring.

8. The preparation method according to claim 1, characterized in that, In step S1, the organic solvent is selected from at least one of tetrahydrofuran, cyclohexane, acetone, and dichloromethane.

9. The preparation method according to claim 1, characterized in that, In step S1, the content of styrene-butadiene-styrene block copolymer in the polymer solution is 1wt%~50wt%.

10. The preparation method according to claim 1, characterized in that, In step S2, the molar ratio of styrene-butadiene-styrene block copolymer to carboxyl-containing thiol in the polymer solution is 0.01 to 1:

1.

11. The preparation method according to claim 1, characterized in that, In step S2, the molar ratio of the carboxyl-containing thiol to the peroxide or azo compound free radical initiator is 60-120:

1.

12. The preparation method according to claim 1, characterized in that, In step S2, the conditions for the heating reaction include: a reaction temperature of 40~80℃ and a reaction time of 1h~8h.

13. The preparation method according to claim 1, characterized in that, In step S2, the grafting rate of the carboxylated styrene-butadiene-styrene block copolymer is 1 wt% to 15 wt%.

14. The preparation method according to claim 1, characterized in that, In step S2, the carboxyl-containing thiol is selected from at least one of 3-mercaptopropionic acid and 2-mercaptoacetic acid.

15. The preparation method according to claim 1, characterized in that, In step S2, the peroxide or azo compound is selected from at least one of dodecyl peroxide, cyclohexanone peroxide, benzoyl peroxide, azobisisobutyronitrile, and azobisisoheptanenitrile.

16. The preparation method according to claim 1, characterized in that, In step S3, the molar ratio of the functional groups in the alkali metal or alkaline earth metal hydroxide to the carboxylated styrene-butadiene-styrene block copolymer is 0.01 to 3:

1.

17. The preparation method according to claim 1, characterized in that, In step S3, the concentration of the alkali metal or alkaline earth metal hydroxide solution is 0.00005~0.02 mol / mL.

18. The preparation method according to claim 1, characterized in that, In step S3, the conditions for the neutralization reaction include: a reaction temperature of 40~80℃ and a reaction time of 1~8h.

19. The preparation method according to claim 1, characterized in that, In step S3, the alkali metal or alkaline earth metal hydroxide is selected from at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide.

20. The preparation method according to claim 1, characterized in that, In step S4, the weight ratio of the ionomer solution to water is 1:1~3.

21. The preparation method according to claim 1, characterized in that, In step S4, the mixing conditions further include mixing at a temperature of 30~70℃, and then stabilizing at 50℃~60℃ for 0.5 h~24 h.

22. The preparation method according to claim 1, characterized in that, In step S5, the conditions for vacuum distillation include: stirring, distillation temperature of 30 ℃ to 100 ℃, and solvent removal rate of 0.001 mL / s to 20 mL / s.

23. The preparation method according to claim 1, characterized in that, In step S5, the conditions for vacuum distillation also include: removing the organic solvent and some water by vacuum distillation until the organic solvent content in the polymer emulsion is less than 0.5 wt%.

24. The use of the soap-free emulsion of the styrene-butadiene-styrene block copolymer according to any one of claims 1 to 6, and the soap-free emulsion of the styrene-butadiene-styrene block copolymer prepared according to any one of claims 7 to 23, in the preparation of rubber products, adhesives, and coatings.

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