SEBS-loaded barium sulfate masterbatch, preparation method, and barium sulfate-filled polyolefin elastomer materials.

Abstract

This invention discloses SEBS-loaded barium sulfate masterbatch, its preparation method, and barium sulfate-filled polyolefin elastomer materials. The masterbatch comprises SEBS, barium sulfate, and a barium sulfate surface treatment agent. The weight ratio of SEBS to barium sulfate is 1:0.2-1.5, and the amount of the barium sulfate surface treatment agent used is 2-15 wt% of the weight of the barium sulfate powder. The barium sulfate surface treatment agent comprises a block copolymer composed of polyethylene glycol monomethyl ether and methyl methacrylate, with a molar ratio of polyethylene glycol monomethyl ether to methyl methacrylate of 1:1-4. The theoretical molecular weight of the barium sulfate surface treatment agent is 300-600. This invention achieves continuous preparation of SEBS-loaded barium sulfate masterbatch by surface treatment of barium sulfate in solution and continuous convection mixing of barium sulfate suspension and SEBS solution, followed by continuous solvent removal after mixing. This masterbatch can be applied to polyolefin elastomers to modify the overall properties of barium sulfate-filled polyolefin elastomer materials.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials, specifically, it relates to a SEBS-loaded barium sulfate masterbatch, its preparation method, and a barium sulfate-filled polyolefin elastomer material. Background Technology

[0002] Polyolefin elastomers are polymeric materials that combine the properties of rubber and thermoplastics, exhibiting high elasticity at room temperature and the ability to be plasticized and molded at high temperatures. Hydrogenated styrene-butadiene-styrene block copolymer (SEBS) is a triblock copolymer composed of styrene (S), hydrogenated butadiene (EB), and styrene (S). In the molecular structure of SEBS, styrene and soft segments are alternately linked, forming a unique microphase separation structure. This structure endows SEBS with excellent elasticity and thermoplasticity, making it a typical polyolefin elastomer. Due to its good heat resistance, weather resistance, and aging resistance, SEBS is used as a main raw material in the production of final parts in fields such as automotive parts, medical devices, and sporting goods. However, the production cost of SEBS is relatively high, and its performance may still not meet the actual needs in certain specific applications. Therefore, by combining SEBS with other polyolefin components, inorganic filler components, and functional components through physical blending, polyolefin elastomers that better meet practical application requirements can be prepared.

[0003] Building upon SEBS, blending can introduce rigid polyolefin components such as polyethylene (PE) and polypropylene (PP), or add elastic components with different structural characteristics, such as ethylene propylene diene monomer (EPDM) and ethylene / α-olefin copolymer (POE), thereby forming polyolefin elastomer materials with a wider performance range. Furthermore, blending can also incorporate inorganic fillers into the broken-down polyolefin components, effectively improving the rigidity, hardness, and abrasion resistance of thermoplastic elastomers, while also enhancing the thermal properties of polyolefin elastomers and effectively controlling the overall cost of the material.

[0004] Barium sulfate is a typical inorganic component, and its non-toxic, odorless, and chemically stable properties make it particularly suitable as a filler component in medical polyolefin elastomer materials, added through blending. More importantly, due to its high density, high refractive index, good hiding power, and electromagnetic shielding properties, barium sulfate composites with polyolefin elastomers can be used to manufacture various medical consumables such as stents and catheters. These consumables exhibit good imaging results under X-rays, appearing clearly in images, which helps doctors accurately place and manipulate these consumables during surgery or treatment.

[0005] However, as a typical inorganic compound, barium sulfate has a large number of hydroxyl groups on its surface, making it highly reactive and polar. Its chemical properties differ significantly from those of polyolefin components. When directly filled into polyolefin components, barium sulfate exhibits a strong tendency to self-aggregate, making the filling process extremely difficult and resulting in a lack of uniform dispersion. Therefore, in industrial-scale production, using only screw extruders for extrusion blending is insufficient to achieve uniform dispersion of untreated barium sulfate in polyolefins. Similarly, untreated barium sulfate, when forcibly filled into polyolefin components, easily precipitates noticeably on the material surface. In such cases, the mechanical properties and imaging effects of the material are unsatisfactory, failing to meet the requirements of medical products. To achieve efficient filling of barium sulfate in polyolefins and prepare high-performance composite materials, barium sulfate is typically surface-treated and pre-dispersed in polyolefins to form masterbatches.

[0006] Traditional barium sulfate surface treatment methods typically involve thoroughly mixing a surface treatment aid with barium sulfate, a process often carried out in a stirring and mixing device. This mixing process presents several problems: firstly, barium sulfate easily becomes airborne during mixing, causing dust pollution; secondly, the flowability of the surface aid after contact with barium sulfate is restricted, resulting in insufficient surface treatment efficiency.

[0007] Methods for forming masterbatches by blending surface-treated barium sulfate with polyolefin components are currently divided into two categories: melt blending and solution blending. Melt blending uses a mixer or extruder, heating the polyolefin components while adding barium sulfate in a molten state. This method is energy-intensive, difficult to achieve high-filling-ratio barium sulfate addition, and generates significant dust pollution during the mixing process. Solution blending involves adding surface-treated barium sulfate to a solution containing the polyolefin components, mixing them mechanically, and finally removing the solvent to obtain polyolefin-loaded barium sulfate masterbatch. Solution blending solves the problems of melt blending, but it also suffers from time-consuming blending processes and discontinuous processing, such as non-continuous and equal-volume masterbatch production, resulting in less than ideal industrial production efficiency.

[0008] To further optimize the solution blending preparation of barium sulfate masterbatch for polyolefins and improve its yield, it is crucial to develop a method that enables continuous production of masterbatch, matches industrialized production line processes, and ensures that the masterbatch meets the requirements of high-performance barium sulfate-filled polyolefin elastomer materials.

[0009] In view of this, the present invention is proposed. Summary of the Invention

[0010] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a SEBS-loaded barium sulfate masterbatch, its preparation method, and a barium sulfate-filled polyolefin elastomer material. This invention develops a barium sulfate surface treatment aid that can fully bind to the surface of barium sulfate in solution and overcome the poor compatibility of barium sulfate with polymers. This further enables surface treatment of barium sulfate in solution, yielding an organic suspension of barium sulfate. Based on this, continuous preparation of the SEBS-loaded barium sulfate masterbatch is achieved through continuous convective mixing of the barium sulfate suspension and the SEBS solution, followed by continuous solvent removal after mixing. This masterbatch can be applied to polyolefin elastomers to modify the overall properties of barium sulfate-filled polyolefin elastomer materials.

[0011] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0012] This invention first designs a novel and highly efficient barium sulfate surface treatment additive, which can fully coat barium sulfate, significantly altering its hydrophilic and highly polar surface characteristics and improving its binding affinity with polyolefin components, while also meeting the requirements for surface treatment of barium sulfate in solution. Furthermore, this invention uses SEBS, a typical polyolefin elastomer soluble in organic solvents, as the polymer component and employs a liquid-phase surface treatment method for barium sulfate, avoiding the low efficiency and dust pollution of traditional barium sulfate surface treatment processes. Simultaneously, it utilizes a convection impingement method between the modified barium sulfate suspension and the SEBS solution to achieve thorough mixing, thereby solving the problem of discontinuous masterbatch production during solution blending. Finally, after mixing, the product is introduced into high-temperature boiling water to evaporate and remove the organic solvent, and then collected and reused, ensuring continuous and low-cost production. Based on the SEBS-loaded barium sulfate masterbatch prepared using the above method, various polyolefin elastomer materials with different properties can be derived.

[0013] More specifically, this invention first prepares an mPEG-MMA block copolymer composed of polyethylene glycol monomethyl ether (mPEG) and methyl methacrylate (MMA) through oxyanionic polymerization. Based on the characteristics of this additive, a method is developed to add barium sulfate to cyclohexane and treat it with mPEG-MMA, thereby obtaining an organic suspension of surface-treated barium sulfate. As a surface treatment additive for barium sulfate, mPEG-MMA fully binds to the barium sulfate surface, overcoming the characteristic of barium sulfate's poor compatibility with polymers. This allows the organic suspension of surface-treated barium sulfate to fully integrate with the polyolefin elastomer components after mixing and contacting with the SEBS solution, achieving highly uniform dispersion. Furthermore, this invention places the organic suspension and the SEBS solution in two separate containers, and through flow rate adjustment, achieves proportional mixing of the two liquids. Mixing is achieved through flow impact, and the solvent is removed by immersion in boiling water to prepare a SEBS-loaded barium sulfate masterbatch. This enables continuous preparation of the masterbatch and ensures that the barium sulfate in the masterbatch is fully loaded and uniformly dispersed. This invention also clarifies a method for applying the corresponding masterbatch in the preparation of barium sulfate-filled polyolefin elastomer materials through conventional blending. Verification confirmed that mPEG-MMA was successfully synthesized according to the intended structure, and that the designed method effectively combined with barium sulfate and improved its surface characteristics. SEBS-loaded barium sulfate masterbatch was also successfully prepared, with the barium sulfate loading in the masterbatch essentially consistent with the design, and the barium sulfate was pre-dispersed. Further comparison confirmed that the polyolefin composite material with the SEBS-loaded barium sulfate masterbatch prepared by the method described in this invention exhibits good mechanical properties and elasticity. The preparation process of the SEBS-loaded barium sulfate masterbatch described in this invention is simple and easy to implement, and the preparation process can be carried out continuously. The obtained masterbatch can also be compounded with polyolefin elastomers through conventional twin-screw melt extrusion to prepare the corresponding elastomer composite material, making it easy to achieve continuous industrial production conversion.

[0014] In a first aspect, the present invention provides a barium sulfate surface treatment aid comprising a block copolymer composed of polyethylene glycol monomethyl ether (mPEG) and methyl methacrylate (MMA), wherein the molar ratio of the polyethylene glycol monomethyl ether to the methyl methacrylate is 1:1-4, and the theoretical molecular weight of the barium sulfate surface treatment aid is 300-600.

[0015] In a further embodiment, the block copolymer contains polyethylene glycol monomethyl ether with an average number of 4-5 repeating units and methyl methacrylate with 1-4 repeating units.

[0016] The mPEG-MMA of this invention is a block copolymer of ethylene glycol and acrylate, wherein the ester groups can react with the hydroxyl groups on the surface of barium sulfate, promoting the full adhesion of mPEG-MMA to the barium sulfate surface and achieving modification of barium sulfate. Simultaneously, the polyether structure in the polyethylene glycol segments can also bind to the hydroxyl groups on the barium sulfate surface via hydrogen bonds, thereby achieving the coating of the surface treatment aid mPEG-MMA on the barium sulfate surface, minimizing the exposed hydrophilic groups on the barium sulfate surface, improving the affinity between barium sulfate and polymer components, and reducing its self-aggregation tendency. More importantly, in organic solutions, the abundant polyether structure of mPEG-MMA can also promote its aggregation towards suspended barium sulfate particles under polar conditions, thus providing a basis for surface treatment of barium sulfate in organic solutions.

[0017] This invention obtains a barium sulfate surface treatment additive with a desired molecular weight by controlling the addition ratio of polyethylene glycol monomethyl ether (mPEG) and methyl methacrylate (MMA). The mPEG-MMA block copolymer of this invention has a specific repeating unit structure and a narrow relative molecular mass distribution. Using mPEG-MMA under specific conditions, surface treatment of barium sulfate in an organic solvent can be achieved. Barium sulfate can fully bind with mPEG-MMA, and the hydrophilicity of the surface-treated barium sulfate is significantly reduced, allowing it to fully interpenetrate and bind with the polyolefin elastomer component in solution, achieving uniform dispersion of barium sulfate in the SEBS component, thus providing a basis for the preparation of SEBS-loaded masterbatch. After barium sulfate is surface-treated with mPEG-MMA and loaded into SEBS to prepare masterbatch, it can also significantly modify the overall performance of the corresponding filled polyolefin elastomer material, thereby improving the performance of barium sulfate-filled polyolefin elastomer materials in different application scenarios.

[0018] Secondly, the present invention provides a method for preparing a barium sulfate surface treatment aid, comprising:

[0019] (1) Heat the container and evacuate it, then fill it with inert gas and allow the container to cool to room temperature;

[0020] (2) Maintain an inert gas environment, add polyethylene glycol monomethyl ether into the container, add solvent, and shake to dissolve it;

[0021] (3) Add sodium hydride or potassium hydride into the container and react for 1-3 hours at 20-30℃;

[0022] (4) Mix methyl methacrylate with a solvent to form a solution, and add the solution dropwise into a container, maintaining a temperature of 20-30°C, and continue the reaction for 2-4 hours;

[0023] (5) Add methanol dropwise into the container to terminate the reaction and collect the reaction product;

[0024] (6) Remove the solvent from the reaction product to obtain barium sulfate surface treatment aid mPEG-MMA.

[0025] In a further step, in step (1), the container is heated to 100-180°C.

[0026] In a further embodiment, the inert gas can be a commonly used inert gas, such as nitrogen.

[0027] As a more specific approach, in step (1), the prepared container is fully sealed and connected to a vacuum device via a conduit. While heating the container to 100-180°C, the container is evacuated to a vacuum. Then the vacuum is turned off, the conduit is connected to a nitrogen supply system, nitrogen is introduced into the container, and the container is cooled to room temperature. The above operations are repeated 3 times.

[0028] This step aims to thoroughly remove oxygen, carbon dioxide, and moisture from the reaction space to prevent these substances from damaging the ion initiator and causing the active center to become inactive.

[0029] In a further embodiment, in step (2), the weight of the solvent added is 2-4 times the weight of polyethylene glycol monomethyl ether;

[0030] Preferably, the solvent is selected from tetrahydrofuran;

[0031] Preferably, the average molecular weight of the polyethylene glycol monomethyl ether is 200.

[0032] As a more specific approach, in step (2), without disrupting the nitrogen environment inside the container, mPEG with an average molecular weight of 200 is added to the prepared container, and then 2-4 times the weight of tetrahydrofuran (THF) is added as a solvent. The mPEG is then fully dissolved by shaking.

[0033] As a solvent, THF has low viscosity and high solubility, providing good flowability. At the same time, THF has moderate polarity, avoiding the problems of initiator association and low initiation efficiency, making it an essential solvent for the oxyanionic polymerization of polar monomers.

[0034] In a further embodiment, in step (3), the molar ratio of sodium hydride or potassium hydride to polyethylene glycol monomethyl ether is 1:1, preferably sodium hydride.

[0035] In step (4), the molar ratio of polyethylene glycol monomethyl ether to methyl methacrylate is 1:1-4;

[0036] Preferably, in step (4), the weight of the solvent in the solution is 2-4 times the weight of methyl methacrylate;

[0037] More preferably, the solvent is selected from tetrahydrofuran.

[0038] As a more specific approach, in step (4), sodium hydride of the same molar amount as mPEG is added to the container, that is, the weight of sodium hydride added is 12% of the weight of mPEG, and the reaction is carried out at 20-30°C for 1-3 hours.

[0039] Prepare a container with 1-4 times the molar weight of mPEG in MMA (i.e., MMA weight is 0.5-2 times the mPEG weight), and thoroughly mix it with 2-4 times the weight of THF in THF to form a solution. Add this solution dropwise to the container. Maintain the temperature at 20-30℃ and continue the reaction for 2 hours. Then, add methanol dropwise to the container to terminate the reaction and collect the reaction product.

[0040] This reaction is a typical oxoanionic polymerization, utilizing the oxoanions generated by sodium hydride in a polar solvent as active centers to initiate the polymerization of acrylate monomers. By combining this method, it is possible to synthesize structure-specific mPEG-MMA block copolymers with narrow molecular weight distributions at room temperature.

[0041] In a further step (6), the collected product is subjected to vacuum distillation to remove THF, washed with ethanol, and then vacuum distilled again. Finally, the obtained product is centrifuged to remove the solvent, thus obtaining the barium sulfate surface treatment aid mPEG-MMA.

[0042] Based on the feeding ratio and the average molecular weight of mPEG, the average number of repeating units of mPEG in the mPEG-MMA segment synthesized in this invention is 4.5, the number of repeating units of MMA is 1-4, and the theoretical molecular weight of the overall product is between 300-600.

[0043] Thirdly, the present invention provides an application of the barium sulfate surface treatment aid described above or the preparation method described above in the preparation of a surface-treated barium sulfate organic suspension.

[0044] Fourthly, the present invention provides a method for preparing a surface-treated barium sulfate organic suspension, comprising:

[0045] Take barium sulfate powder, add it to an organic solvent and mix thoroughly to prepare an organic suspension. Add the barium sulfate surface treatment aid described in the first aspect or the barium sulfate surface treatment aid prepared by the preparation method described in the second aspect into the suspension. Stir and mix at a certain temperature to obtain a surface-treated barium sulfate organic suspension.

[0046] Preferably, the weight of the barium sulfate powder is 8-20 wt% of the weight of the organic solvent;

[0047] Preferably, the high-speed stirring speed is 500-2000 rpm;

[0048] Preferably, the average particle size of the barium sulfate powder is 100-400 nm.

[0049] As a specific approach, the method for preparing a surface-treated barium sulfate organic suspension includes:

[0050] (1) Mixing of barium sulfate organic suspension:

[0051] Take barium sulfate powder that has not undergone any surface chemical treatment and has an average particle size of 100-400 nm, and then weigh out organic solvent at a weight of 8-20 wt% of the weight of the barium sulfate powder.

[0052] Preferably, the solvent is cyclohexane.

[0053] Take 2-15 wt% of barium sulfate and mPEG-MMA, and mix barium sulfate, organic solvent and mPEG-MMA.

[0054] The mPEG-MMA designed in this invention has a molecular weight between 300 and 600, which is moderate and has a low overall viscosity. This allows it to fully enter the organic solvent in a short time, providing a basis for subsequent modification reactions.

[0055] (2) Reaction combination:

[0056] The barium sulfate organic suspension mixed with mPEG-MMA is placed in an environment of 45-60℃ and stirred at a speed of 500-2000 rpm to allow the surface additives to react with the barium sulfate for 1-2 hours, finally obtaining surface-treated barium sulfate powder.

[0057] mPEG-MMA is a block copolymer of ethylene glycol and acrylate. The ester groups in mPEG-MMA can react with the hydroxyl groups on the surface of barium sulfate at a certain temperature, promoting the full adhesion of mPEG-MMA to the barium sulfate surface and thus modifying the barium sulfate. Simultaneously, the polyether structure in the polyethylene glycol segments can also bind to the hydroxyl groups on the barium sulfate surface via hydrogen bonds. This allows the surface treatment agent mPEG-MMA to coat the barium sulfate surface, minimizing the exposed hydrophilic groups on the barium sulfate surface, improving the affinity between barium sulfate and polymer components, and reducing its self-aggregation tendency. Due to the high proportion of polyether and polyester structures in mPEG-MMA, in organic solutions of barium sulfate, mPEG-MMA tends to aggregate towards suspended barium sulfate particles under polar induction, thus enabling surface treatment of barium sulfate in organic solutions.

[0058] Fifthly, the present invention provides a SEBS-loaded barium sulfate masterbatch, comprising SEBS, barium sulfate, and the barium sulfate surface treatment aid described in the first aspect, wherein the weight ratio of SEBS to barium sulfate is 1:0.2-1.5, and the amount of barium sulfate surface treatment aid used is 2-15 wt% of the weight of barium sulfate powder.

[0059] The barium sulfate surface treatment aid comprises a block copolymer of polyethylene glycol monomethyl ether and methyl methacrylate, wherein the molar ratio of polyethylene glycol monomethyl ether to methyl methacrylate is 1:1-4, and the theoretical molecular weight of the barium sulfate surface treatment aid is 300-600.

[0060] In the block copolymer, the average number of repeating units of polyethylene glycol monomethyl ether is 4-5, and the number of repeating units of methyl methacrylate is 1-4.

[0061] Sixthly, the present invention provides a method for preparing SEBS-supported barium sulfate masterbatch, comprising:

[0062] (1) Preparation of barium sulfate surface treatment additive;

[0063] (2) Take barium sulfate powder, add it to an organic solvent, then add the barium sulfate surface treatment additive, stir and mix to obtain a surface-treated barium sulfate organic suspension;

[0064] (3) Add SEBS to an organic solvent, stir and mix to prepare a SEBS solution;

[0065] (4) The SEBS solution and the surface-treated barium sulfate organic suspension are placed in containers respectively, and the liquid outflow rate of the two containers can be adjusted. After the SEBS solution and the surface-treated barium sulfate organic suspension flow out of the containers and merge, they enter boiling water to remove the solvent, coagulate to obtain masterbatch, and dry to obtain SEBS-loaded barium sulfate masterbatch.

[0066] In step (1), the preparation method of barium sulfate surface treatment additive is as described in the second aspect.

[0067] In step (2), the preparation method of the surface-treated barium sulfate organic suspension is as described in the fourth aspect.

[0068] In step (3), SEBS is taken and added to an organic solvent. The mixture is stirred thoroughly at 40-60°C for 20-40 minutes to prepare a SEBS solution.

[0069] In a further embodiment, in step (3), the weight of SEBS is 10-25 wt% of the weight of the organic solvent, and the stirring speed is 500-2000 rpm.

[0070] In a further embodiment, the organic solvent is preferably cyclohexane.

[0071] As a more specific approach, in step (3), SEBS and organic solvent are weighed according to the weight of SEBS being 10-25 wt% of the weight of organic solvent. SEBS is added to the organic solvent and placed at 40-60℃. The mixture is stirred thoroughly for 20-40 minutes to prepare the SEBS solution.

[0072] This step aims to control conditions to ensure that SEBS dissolves quickly in the organic solvent while preventing the solvent from evaporating. It also requires controlling the viscosity of the SEBS solution to maintain its good flowability and processability.

[0073] As an organic solvent, cyclohexane has a boiling point of 80.7℃ and a solubility parameter of 7.2 (cal / cm³). 3 ) 1 / 2 Cyclohexane was chosen as the solvent for SEBS primarily because its solubility parameters are close to those of SEBS, allowing for rapid and complete dissolution. Secondly, cyclohexane's boiling point is significantly higher than the temperatures required for SEBS dissolution and barium sulfate surface treatment, ensuring minimal solvent evaporation loss and maintaining operational stability. Furthermore, cyclohexane's boiling point is significantly lower than that of water, allowing for complete evaporation during the final solvent removal process, thus ensuring the successful preparation of the masterbatch.

[0074] In step (4), the SEBS solution and the organic suspension of treated barium sulfate are placed in containers where the liquid outflow rate is regulated by pressure.

[0075] Connect the outlets of the two containers with a T-connector to allow the liquids in the two containers to merge and then flow down;

[0076] A container is connected below the pipeline outlet, and water is kept boiling inside the container. A pumping device is connected above the container to collect the volatile solvent for reuse.

[0077] Open the outlets of the two containers, adjust the liquid outflow rate of the two containers according to the designed barium sulfate loading, and after the two solutions are impacted and mixed, they fall into the boiling water below. The solvent is removed by boiling and coagulation to obtain SEBS loaded barium sulfate masterbatch.

[0078] The collected SEBS-loaded barium sulfate masterbatch particles were then placed in an oven at 70°C and left to dry for 16-32 hours until completely dry, thus obtaining barium sulfate masterbatch.

[0079] In a further step, in step (4), the flow rate of the solution in the two containers is adjusted according to the weight ratio of SEBS in the SEBS solution and the weight ratio of barium sulfate in the surface-treated barium sulfate organic suspension, combined with the requirement that the weight ratio of SEBS to barium sulfate in the final masterbatch is 1:0.2-1.5.

[0080] At a certain flow rate, the SEBS solution and the surface-treated barium sulfate organic suspension converge, and the two liquids mix after turbulent impact. Since both liquids use cyclohexane as their organic solvent, they can rapidly fuse together. The affinity between the surface-treated barium sulfate and the organic polymer SEBS is also significantly improved. Therefore, during the mixing process generated by external convection, the surface-treated barium sulfate particles can easily enter the spaces between the SEBS molecular chains, achieving interpenetration bonding. After the solvent cyclohexane is removed through evaporation, the barium sulfate remains within the SEBS molecular chains, forming SEBS-loaded barium sulfate masterbatch.

[0081] After the liquids in the two containers merge, they flow down further. A container is connected below the outlet of the pipeline, and water that is kept boiling is placed in the container. After the mixed liquid enters the boiling water, the cyclohexane evaporates and is removed because the temperature exceeds the boiling point. The remaining SEBS retains the state of barium sulfate wrapped between the molecular chains, thus realizing the preparation of the corresponding masterbatch.

[0082] In this process, the liquid in the container containing the barium sulfate organic suspension and SBES solution can be continuously replenished, the boiling water in the lower container can be kept boiling, the pumping equipment connected to the upper container can continuously collect the volatile solvent, and the obtained masterbatch can be continuously transported out of the container through the conveying equipment. Therefore, the preparation process of this masterbatch can be carried out continuously.

[0083] In a further step, in step (4), the SEBS-loaded barium sulfate masterbatch can be used as a raw material for preparing polyolefin elastomers after being thoroughly dried.

[0084] In a seventh aspect, the present invention provides a barium sulfate-filled polyolefin elastomer material, comprising:

[0085] The SEBS-loaded barium sulfate masterbatch contains 10-75 wt%, SEBS 0-80%, SBS 0-90 wt%, POE 0-90 wt%, PP 0-45 wt%, and PE 0-45 wt%, including the SEBS used in the SEBS-loaded barium sulfate masterbatch. The total amount of SBS, SEBS, and POE is 50-98 wt%.

[0086] The polyolefin elastomer material of the present invention includes at least one polymer selected from butadiene-styrene copolymer (SBS), hydrogenated styrene-butadiene block copolymer (SEBS), and ethylene-α-olefin copolymer elastomer (POE), at least one polymer selected from polypropylene (PP) and polyethylene (PE), and the SEBS-loaded barium sulfate masterbatch provided by the present invention.

[0087] Compared to similar materials prepared from ordinary barium sulfate or surface-treated barium sulfate, the filled polyolefin elastomer material prepared by the present invention using SEBS-loaded barium sulfate masterbatch has superior mechanical properties and higher resilience.

[0088] Eighthly, the present invention provides a method for preparing a barium sulfate-filled polyolefin elastomer material, comprising:

[0089] (1) Mix at least one of SBS, SEBS, and POE with at least one of PP, PE, and SEBS-loaded barium sulfate masterbatch;

[0090] This process involves adding all raw materials into a low-speed mixer and mixing them at 150 rpm for 2 minutes to obtain a well-blended mixture.

[0091] (2) Then, the material is melt-extruded by a twin-screw extruder, granulated, and barium sulfate-filled polyolefin elastomer material is obtained.

[0092] This process can utilize existing conventional twin-screw extruders and extrusion conditions. For example, the selected twin-screw extruder has an aspect ratio of 48–56:1, the vacuum extraction pressure in the metering section is set to -0.85–-0.95 MPa, the temperature of each section of the screw is set in the range of 130–230°C, and the main extruder speed is set to 200–400 rpm. The blended mixture is added to the twin-screw extruder through the main feed port for melt extrusion, and after pelleting, the corresponding barium sulfate-filled polyolefin elastomer material is obtained.

[0093] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0094] (1) This invention prepares an mPEG-MMA block copolymer with a relative molecular weight of 300-600 by controlling the amount of mPEG and MMA added through oxyanionic polymerization, and applies it to the surface treatment of barium sulfate in organic solvent. It makes full use of the characteristics of low molecular weight and rich polyether and polyester structures, so that it can be quickly and uniformly mixed with barium sulfate in solvent and achieve surface treatment of barium sulfate under the corresponding conditions. The reaction method is simple and easy to implement.

[0095] (2) Utilizing the organic properties of mPEG-MMA, it combines with the hydroxyl groups on the surface of barium sulfate and coats the surface of barium sulfate, thereby minimizing the exposed hydrophilic groups on the surface of barium sulfate and fully combining them on the surface of barium sulfate. This significantly overcomes the characteristic that barium sulfate is difficult to be compatible with polymers, allowing the surface-treated barium sulfate to penetrate into the SEBS molecule in the organic solvent, thus achieving the blending of SBES and barium sulfate in the liquid phase.

[0096] (3) Taking advantage of the large spacing and low interaction force between SEBS molecules in the SEBS solution, the barium sulfate component in the suspension is inserted into the SEBS molecules by means of the confluence and impact of the SEBS solution and the barium sulfate suspension, and the barium sulfate masterbatch structure is constructed by impact flow.

[0097] (4) By combining the continuous flow of SBES solution and barium sulfate suspension, the continuous boiling of water, the continuous discharge of volatile solvent, and the continuous delivery of masterbatch products, the continuous preparation of SEBS-loaded barium sulfate masterbatch was realized, and the overall performance of barium sulfate-filled polyolefin elastomer materials was further improved by utilizing the masterbatch.

[0098] (5) All kinds of equipment involved in this invention are commercially available equipment, and the raw materials are widely available. The overall solution is easy to implement.

[0099] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0100] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0101] Figure 1 The infrared spectrum of the surface-treated barium sulfate organic suspension prepared according to the preparation method described in Example 3 after complete drying;

[0102] Figure 2 This is a scanning electron microscope (SEM) image of the barium sulfate-filled polyolefin elastomer material prepared according to the preparation method described in Example 7.

[0103] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0104] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0105] The detection method used in this invention is as follows:

[0106] 1. Determination of average molecular weight:

[0107] The relative molecular weight of the samples was determined using liquid chromatography-mass spectrometry (LC-MS). Chromatographic grade methanol was used as the mobile phase, with an injection volume controlled at 5 μL. Sample ionization was performed using TIC anodic source ionization mode, combined with a multi-reaction-stage assay to determine the molecular weight.

[0108] 2. Thermogravimetric test:

[0109] Thermogravimetric analysis (TGA) was used to determine thermogravimetric loss. The sample was placed in a TGA crucible and the test was carried out under nitrogen atmosphere. The temperature range was 30°C to 800°C and the heating rate was 10°C / min.

[0110] 3. Water contact angle test:

[0111] Take a small amount of the powder to be tested, place it in a mold, and press it into a sheet under a pressure of 10 MPa. Using a contact angle tester, operate a micro syringe to drop water droplets onto the surface of the silicon dioxide sheet. Keep the first image after the water droplets have completely dripped. The angle between the tangent of the water droplet surface and the sample in the image is the contact angle.

[0112] 4. Fourier transform infrared spectroscopy analysis:

[0113] A small amount of completely dried test powder was mixed with potassium bromide powder and ground. The mixture was then placed in a mold and pressed into a thin sheet under a pressure of 10 MPa. The pressed sheet was then analyzed using an infrared spectrometer with the test wavenumber set to 400 cm⁻¹. -1 Up to 4000cm -1 .

[0114] 5. Tensile strength:

[0115] Tensile properties were tested according to GB / T 528-2009. Standard dumbbell-shaped specimens were cut using a cutting tool, with a thickness of 2±0.2 mm and a working area width of 6 mm. The specimen was fixed to the fixture of an electronic tensile testing machine, and the extensometer was clamped in the working area of ​​the specimen at a distance of 25 mm. Tensile strength was applied at a rate of 500 mm / min until the specimen broke. The tensile strength, stress at 300% elongation, and elongation at break were recorded.

[0116] 6. Permanent deformation due to fracture:

[0117] In the tensile strength test, a 25mm long area is marked in the working area of ​​the specimen beforehand. When the specimen is fixed to the fixture of the electronic tensile testing machine, the extensometer is aligned with the marked line and clamped onto the specimen. After the specimen breaks under tension, the broken specimen is collected. 24 hours later, the specimen is spliced ​​together, and the length of the area within the marked line is measured as L. The permanent deformation at fracture is calculated according to R = (L-25) / 25×100%.

[0118] 7. Tear strength:

[0119] Tear strength was tested according to GB / T 529-2008. Standard right-angled specimens with a thickness of 2±0.2 mm were cut using a standard cutter. The specimens were fixed to the fixture of an electronic tensile testing machine and subjected to a tear test at a rate of 500 mm / min until the specimens broke. The tear strength of the specimens was recorded.

[0120] Example 1

[0121] Four 1000ml flasks were placed in four oil baths, with the oil bath temperature set to 180°C. The flasks were thoroughly sealed and connected to a vacuum pump via tubing. During heating, the vacuum pump was turned on, and all four flasks were gradually evacuated to a vacuum. After the flask temperature reached above 160°C, the vacuum was turned off after 2 minutes. Then, the flasks were sequentially connected to nitrogen cylinders via tubing, and each flask was filled with nitrogen gas. All flasks were allowed to cool to room temperature. This process was repeated three times to prepare the four reaction vessels.

[0122] Using a syringe, add 30g of mPEG with an average molecular weight of 200 to the prepared flask. Then, using a syringe, add 60g of THF as a solvent. Shake repeatedly for 2 minutes to ensure the mPEG is fully dissolved. Repeat the same operation for all four flasks. Inject 3.6g of sodium hydride into each of the four flasks and react in an oil bath at 30°C for 1 hour.

[0123] Prepare 15g, 30g, 45g, and 60g of MMA and place them in four beakers (numbered 1-4). Then, add 60g, 120g, 180g, and 240g of THF to the four beakers respectively, ensuring thorough mixing of the MMA and THF to form solutions. Add the MMA solutions from beakers 1-4 dropwise to four flasks, maintaining all flasks in an oil bath at 20°C for 4 hours. After the reaction time, add methanol dropwise to the four flasks to terminate the reaction. Open the flasks and collect the reaction products. Add the products sequentially to a rotary evaporator, remove THF by vacuum distillation, wash with ethanol, and then distill again under vacuum. Centrifuge the four products to remove the solvent, yielding barium sulfate surface additives mPEG-MMA with theoretical molecular weights of 300, 400, 500, and 600, respectively.

[0124] The four products were analyzed by mass spectrometry using liquid chromatography-mass spectrometry (LC-MS), and their average molecular weight and molecular structure were determined. The results are shown in Table 1. The results show that the main molecular composition of the obtained products is consistent with the design, and the measured average molecular weight is also basically consistent with the theoretical molecular weight.

[0125] Table 1

[0126] Sample number Theoretical molecular weight Main molecular composition Determination of average molecular weight mPEG-MMA product 1 300 Ethylene glycol, acrylate 298 mPEG-MMA product 2 400 Ethylene glycol, acrylate 396 mPEG-MMA product 3 500 Ethylene glycol, acrylate 496 mPEG-MMA product 4 600 Ethylene glycol, acrylate 594

[0127] Example 2

[0128] Place a 2000ml flask in an oil bath, set the oil bath temperature to 120℃, seal the flask thoroughly, and connect the flask to a vacuum pump via a tubing. During heating, turn on the vacuum pump and gradually evacuate the flask to a vacuum. After the flask temperature reaches above 100℃, turn off the vacuum after 2 minutes. Then connect the flask to a nitrogen cylinder via a tubing, fill the flask with nitrogen, and wait for the container to cool to room temperature. Repeat the above process 3 times to complete the preparation of the reaction vessel.

[0129] Using a syringe, add 80g of mPEG with an average molecular weight of 200 into the prepared flask. Then, using the syringe, add 320g of THF as a solvent and shake repeatedly for 2 minutes to fully dissolve the mPEG. Inject 20g of potassium hydride into the flask and react for 3 hours in an oil bath at 20°C.

[0130] Prepare 120g of MMA and place it in a beaker. Then add 240g of THF to the beaker, ensuring the MMA and THF are thoroughly mixed to form a solution. Add the MMA solution from the beaker dropwise into a flask, maintaining the flask in an oil bath at 30°C for 2 hours. After the reaction time is up, add methanol dropwise to the flask to terminate the reaction. Open the flask and collect the reaction product. Add the product to a rotary evaporator and remove the THF by vacuum distillation. Wash with ethanol and then distill again under vacuum. Centrifuge the obtained product to remove the solvent, yielding barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 500.

[0131] 1000g of untreated barium sulfate powder with an average particle size of 400nm was divided into five 200g portions and placed into five containers, numbered 1-5. 2500g of cyclohexane was added to each of the five containers, followed by 4g, 8g, 14g, 20g, and 30g of mPEG-MMA (the theoretical molecular weight of 500) to containers 1-5, respectively. The containers were placed in a water bath at 60℃ and stirred at 500rpm for one hour to obtain five surface-treated barium sulfate cyclohexane suspensions. The amounts of the surface-treatment agent mPEG-MMA were 2wt%, 4wt%, 7wt%, 10wt%, and 15wt% of the weight of the barium sulfate powder, respectively.

[0132] Take 30g of each of the five surface-treated barium sulfate cyclohexane suspensions, place them in a container, and remove the organic solvent cyclohexane by freeze-drying to obtain five surface-treated barium sulfate powders, each weighing approximately 2.2g. Take approximately the same amount of untreated barium sulfate powder, wrap each of the six powders in filter paper, and extract using a Soxhlet extractor with cyclohexane as the solvent for 24 hours (refluxing approximately every 15-20 minutes). After extraction, place the products in an oven and dry at 70℃ to constant weight, then perform thermogravimetric analysis (TGA). Based on the characteristics of the barium sulfate powder, the weight loss range can be divided into two intervals: room temperature -120℃ and 120-800℃. The weight loss in the former interval is due to the removal of adsorbed water, while the weight loss in the latter interval is mainly caused by the removal of chemically bound water and the decomposition of surface additives bound to barium sulfate. The corresponding results are shown in Table 2.

[0133] As shown in Table 2, with the increase of the relative amount of mPEG-MMA to barium sulfate, the weight loss of the corresponding barium sulfate samples increased in the 120-800℃ range, while the weight loss decreased in the room temperature-120℃ range. This indicates both a full and strong bond between mPEG-MMA and barium sulfate, and a significant decrease in the hydrophilicity of barium sulfate bound with mPEG-MMA.

[0134] Table 2

[0135]

[0136] Example 3

[0137] Place a 500ml flask in an oil bath, set the oil bath temperature to 160℃, seal the flask thoroughly, and connect the flask to a vacuum pump via a tubing. During heating, turn on the vacuum pump and gradually evacuate the flask to a vacuum. After the flask temperature reaches above 150℃, turn off the vacuum after 2 minutes. Then connect the flask to a nitrogen cylinder via a tubing, fill the flask with nitrogen gas, and wait for the container to cool to room temperature. Repeat the above process 3 times to complete the preparation of the reaction vessel.

[0138] Using a syringe, add 20g of mPEG with an average molecular weight of 200 to the prepared flask. Then, using the syringe, add 60g of THF as a solvent and shake repeatedly for 2 minutes to fully dissolve the mPEG. Inject 2.4g of sodium hydride into the flask and react for 2 hours in an oil bath at 25°C.

[0139] Prepare 20g of MMA and place it in a beaker. Then add 60g of THF to the beaker, ensuring the MMA and THF are thoroughly mixed to form a solution. Add the MMA solution from the beaker dropwise into a flask, maintaining the flask in an oil bath at 25°C for 3 hours. After the reaction time is up, add methanol dropwise to the flask to terminate the reaction. After opening the flask, collect the reaction product and add it to a rotary evaporator. Remove the THF by vacuum distillation, wash with ethanol, and then distill again under vacuum. Centrifuge the obtained product to remove the solvent, yielding barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 400.

[0140] 100g of untreated barium sulfate powder with an average particle size of 300nm was placed in a container. 500g of cyclohexane was added to the container, followed by 8g of mPEG-MMA (the theoretical molecular weight of 400). The container was placed in a water bath at 45℃, and the mixture was stirred at 2000rpm for 2 hours to obtain a surface-treated barium sulfate cyclohexane suspension. The amount of the surface treatment agent mPEG-MMA was 8wt% of the weight of the barium sulfate powder.

[0141] 40g of the surface-treated barium sulfate cyclohexane suspension was placed in a container and the organic solvent cyclohexane was removed by freeze-drying, yielding approximately 7.2g of surface-treated barium sulfate powder. Approximately the same amount of untreated barium sulfate powder was then taken. Fourier transform infrared spectroscopy analysis and particle size determination were performed on both powders. The resulting infrared spectra are shown in the attached figure. Figure 1As shown in Table 3, the average particle size was then pressed into thin sheets at 15 MPa for water contact angle testing. Untreated barium sulfate powder was treated using the same method for control testing, and the results are shown in Table 3.

[0142] Table 3

[0143] Sample number Average particle size Water contact angle Untreated barium sulfate 307nm 33° Example 3: Surface Treatment of Barium Sulfate 304nm 71°

[0144] Results analysis:

[0145] Comparison Appendix Figure 1 Infrared spectra of surface-treated and untreated barium sulfate powders show that the treated barium sulfate sample has a higher concentration in the 2850-2950 cm⁻¹ infrared spectrum. -1 Two distinct peaks were observed within the range, corresponding to the peaks of methylene (–CH2–) and methyl (–CH3), respectively. This further demonstrates that mPEG-MMA and barium sulfate can be fully combined under the surface treatment method described in this invention, giving barium sulfate significant organic properties. Regarding particle size and water contact, it was found that the average particle size of barium sulfate remained essentially unchanged before and after mPEG-MMA treatment, but the water contact angle significantly increased. This indicates that surface treatment of barium sulfate with mPEG-MMA can significantly reduce its hydrophilicity.

[0146] Example 4

[0147] Place a 2000ml flask in an oil bath, set the oil bath temperature to 150℃, seal the flask thoroughly, and connect the flask to a vacuum pump via a tubing. During heating, turn on the vacuum pump and gradually evacuate the flask to a vacuum. After the flask temperature reaches above 130℃, turn off the vacuum after 2 minutes. Then connect the flask to a nitrogen cylinder via a tubing, fill the flask with nitrogen, and wait for the container to cool to room temperature. Repeat the above process 3 times to complete the preparation of the reaction vessel.

[0148] Using a syringe, add 150g of mPEG with an average molecular weight of 200 to the prepared flask. Then, using the syringe, add 400g of THF as a solvent and shake repeatedly for 2 minutes to fully dissolve the mPEG. Inject 18g of sodium hydride into the flask and react for 1.5 hours in an oil bath at 30°C.

[0149] Prepare 75g of MMA and place it in a beaker. Then add 200g of THF to the beaker, ensuring the MMA and THF are thoroughly mixed to form a solution. Add the MMA solution from the beaker dropwise into a flask, maintaining the flask in an oil bath at 25°C for 2.5 hours. After the reaction time is up, add methanol dropwise to the flask to terminate the reaction. Open the flask and collect the reaction product. Add the product to a rotary evaporator, remove THF by vacuum distillation, wash with ethanol, and then distill again under vacuum. Centrifuge the obtained product to remove the solvent, yielding barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 300.

[0150] 2000g of untreated barium sulfate powder with an average particle size of 200nm was placed in a container. 15000g of cyclohexane was added to the container, followed by 200g of mPEG-MMA (the theoretical molecular weight of 300). The container was placed in a water bath at 55℃, and the mixture was stirred at 1000rpm for 1.5 hours to obtain a surface-treated barium sulfate cyclohexane suspension. The amount of the surface treatment agent mPEG-MMA was 10wt% of the weight of the barium sulfate powder.

[0151] Take 2000g of barium sulfate powder with an average particle size of 200nm that has not undergone any surface chemical treatment, put it into a container, and add 15000g of cyclohexane to the container. Place the container in a water bath, adjust the water bath temperature to 55℃, and stir the reaction at 1000rpm for 1.5 hours to obtain an untreated barium sulfate cyclohexane suspension.

[0152] Take 1000g of SEBS powder (brand name 6159) and add it to 10000g of cyclohexane. Adjust the temperature to 40℃ and stir thoroughly at 2000rpm for 40 minutes to prepare a solution in which the weight of SEBS is 10wt% of the weight of the organic solvent.

[0153] Take SEBS solution and organic suspension of untreated barium sulfate, and place them in containers with liquid outflow rate regulated by pressure. Connect the outlets of the two containers with a T-connector to allow the liquids in the two containers to merge and flow further down. Connect a container below the outlet of the pipeline, and place water in the container to keep it boiling. Connect a pumping device above the container to collect the volatile solvent for reuse.

[0154] The liquid outflow rates of the two containers were adjusted to 1:1.55, 1:3.09, 1:5.41, 1:7.23, and 1:11.59, respectively. After the two solutions were mixed by impact, they fell into the boiling water below. The solvent was removed by boiling, and five SEBS-loaded barium sulfate masterbatches without surface treatment were obtained by coagulation, which were designated as masterbatches 1-5#. The state of the masterbatch preparation process was observed and recorded in Table 4.

[0155] Further, the SEBS solution was placed in the first container, and the surface-treated barium sulfate cyclohexane suspension was placed in the second container. The liquid outflow rates of the two containers were adjusted to 1:1.56, 1:3.13, 1:3.82, 1:7.82, and 1:11.73, respectively. After the two solutions were mixed by impact, they fell into the boiling water below. The solvent was removed by boiling, and five SEBS-loaded surface-treated barium sulfate masterbatches were obtained by coagulation, which were designated as masterbatches 6-10#. The state of the masterbatch preparation process was observed and recorded in Table 4.

[0156] The collected SEBS-loaded barium sulfate masterbatch particles were placed in a 70℃ oven and left to dry completely for 16 hours. The weight loss of the 10 masterbatches was analyzed using a thermogravimetric analyzer. The residual amount of different barium sulfate masterbatches was determined when the temperature was increased from room temperature to 800℃ in a nitrogen atmosphere at a rate of 10℃ / min, and compared with the theoretical barium sulfate loading. The results are also recorded in Table 4.

[0157] Table 4

[0158]

[0159] Results analysis:

[0160] As shown in Table 4, surface-treated barium sulfate exhibits better solubility in solution, allowing it to mix more quickly and thoroughly into the SEBS solution. Furthermore, it remains well-retained within the SEBS component during the subsequent boiling water solvent removal process, resulting in a barium sulfate loading in the SEBS masterbatch that is essentially consistent with the design value. In contrast, untreated barium sulfate has difficulty entering the SEBS solution, is not easily dispersed within it, and is more likely to enter the water during boiling water solvent removal, leading to a significantly lower barium sulfate content in the final SEBS masterbatch compared to the theoretical value.

[0161] Example 5

[0162] Place a 4000ml flask in an oil bath, set the oil bath temperature to 160℃, seal the flask thoroughly, and connect the flask to a vacuum pump via a tubing. During heating, turn on the vacuum pump and gradually evacuate the flask to a vacuum. After the flask temperature reaches above 140℃, turn off the vacuum after 2 minutes. Then connect the flask to a nitrogen cylinder via a tubing, fill the flask with nitrogen, and allow the container to cool to room temperature. Repeat the above process three times to complete the preparation of the reaction vessel.

[0163] Using a syringe, add 300g of mPEG with an average molecular weight of 200 to the prepared flask. Then, using the syringe, add 800g of THF as a solvent and shake repeatedly for 2 minutes to fully dissolve the mPEG. Inject 36g of sodium hydride into the flask and react for 2.5 hours in an oil bath at 20°C.

[0164] Prepare 450g of MMA and place it in a beaker. Then add 1000g of THF to the beaker, ensuring the MMA and THF are thoroughly mixed to form a solution. Add the MMA solution from the beaker dropwise into a flask, maintaining the flask in an oil bath at 25°C for 3.5 hours. After the reaction time is reached, add methanol dropwise to the flask to terminate the reaction. Open the flask and collect the reaction product. Add the product to a rotary evaporator, remove the THF by vacuum distillation, wash with ethanol, and then distill again under vacuum. Centrifuge the obtained product to remove the solvent, yielding barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 500.

[0165] 10,000 g of untreated barium sulfate powder with an average particle size of 300 nm was placed in a container. 60,000 g of cyclohexane was added to the container, followed by 500 g of mPEG-MMA (the theoretical molecular weight of 500). The container was placed in a water bath at 50°C, and the mixture was stirred at 1500 rpm for 1.6 hours to obtain a surface-treated barium sulfate cyclohexane suspension. The amount of the surface treatment agent mPEG-MMA was 5 wt% of the weight of the barium sulfate powder.

[0166] Take 2000g of SEBS granules with brand name 8245D, add them to 4000g of cyclohexane, adjust the temperature to 60℃, and stir thoroughly at 500rpm for 20 minutes to prepare a solution in which the weight of SEBS is 25wt% of the weight of the organic solvent.

[0167] Take the SEBS solution and the organic suspension of treated barium sulfate, and place them in containers where the liquid outflow rate is regulated by pressure. Connect the outlets of the two containers with a T-connector to allow the liquids in the two containers to merge and flow further down. Connect a container below the outlet of the pipeline, and place water in the container to keep it boiling. Connect a pumping device above the container to collect the volatile solvent for reuse.

[0168] The liquid outflow rates of the two containers were adjusted to 1:0.47, 1:0.94, 1:1.41, and 1:1.88, respectively. After the two solutions were mixed by impact, they fell into boiling water below, where the solvent was removed through boiling, resulting in coagulation and the formation of four SEBS-loaded barium sulfate masterbatches. The collected SEBS-loaded barium sulfate masterbatch particles were placed in a 70°C oven and left to dry completely for 32 hours. Finally, four masterbatches with barium sulfate loadings of 20wt%, 40wt%, 60wt%, and 80wt% of SEBS weight were obtained, designated as barium sulfate masterbatch 11-14#.

[0169] According to the formulas shown in Table 5, based on a total of 2000g of material for each formula, weigh out the raw materials of the 8 components, add the 8 raw materials to the low-speed mixer in sequence, and mix at 150rpm for 2 minutes to obtain 8 well-mixed mixtures.

[0170] Table 5

[0171]

[0172]

[0173] A twin-screw extruder with a length-to-diameter ratio of 48:1 was selected. The screw was divided into 12 zones. The vacuum extraction pressure in the metering section was set to -0.90 MPa. The temperatures of each screw section were set to 130℃, 190℃, 200℃, 200℃, 210℃, 210℃, 200℃, 200℃, 205℃, 210℃, 210℃, and 220℃. The main extruder speed was set to 200 rpm. The mixed raw materials were added to the twin-screw extruder through the main feed port for melt blending. After pelleting, the corresponding barium sulfate-filled polyolefin elastomer material was obtained. The mechanical properties and permanent deformation characteristics of the obtained material were tested, and the results are shown in Table 6.

[0174] Table 6

[0175]

[0176] As shown in Table 6, compared to using untreated barium sulfate, the polyolefin elastomer materials prepared using the SEBS-loaded barium sulfate masterbatch developed in this invention exhibit superior mechanical properties and lower permanent deformation, which also implies better resilience. The performance advantages of samples using barium sulfate masterbatch become more pronounced with increasing barium sulfate loading.

[0177] Example 6

[0178] Place a 5000ml flask in an oil bath, set the oil bath temperature to 170℃, seal the flask thoroughly, and connect the flask to a vacuum pump via a tubing. During heating, turn on the vacuum pump and gradually evacuate the flask to a vacuum. After the flask temperature reaches above 150℃, turn off the vacuum after 2 minutes. Then connect the flask to a nitrogen cylinder via a tubing, fill the flask with nitrogen, and wait for the container to cool to room temperature. Repeat the above process 3 times to complete the preparation of the reaction vessel.

[0179] Using a syringe, add 400g of mPEG with an average molecular weight of 200 to the prepared flask. Then, using the syringe, add 1000g of THF as a solvent and shake repeatedly for 2 minutes to fully dissolve the mPEG. Inject 48g of sodium hydride into the flask and react for 1.5 hours in an oil bath at 28°C.

[0180] Prepare 400g of MMA and place it in a beaker. Then add 1000g of THF to the beaker, ensuring the MMA and THF are thoroughly mixed to form a solution. Add the MMA solution from the beaker dropwise into a flask, maintaining the flask in an oil bath at 23°C for 3.5 hours. After the reaction time is reached, add methanol dropwise to the flask to terminate the reaction. After opening the flask, collect the reaction product and add it to a rotary evaporator. Remove the THF by vacuum distillation, wash with ethanol, and then distill again under vacuum. Centrifuge the obtained product to remove the solvent, yielding barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 500.

[0181] 10,000 g of untreated barium sulfate powder with an average particle size of 300 nm was placed in a container. 90,000 g of cyclohexane was added to the container, followed by 800 g of mPEG-MMA (the theoretical molecular weight of 400). The container was placed in a water bath at 55°C, and the mixture was stirred at 1200 rpm for 1.2 hours to obtain a surface-treated barium sulfate cyclohexane suspension. The amount of mPEG-MMA used as the surface treatment agent was 8 wt% of the weight of the barium sulfate powder. 40,000 g of the surface-treated barium sulfate cyclohexane suspension was placed in a container, and the organic solvent cyclohexane was removed by freeze-drying to obtain approximately 4285 g of surface-treated barium sulfate powder.

[0182] Take 2000g of SEBS powder (brand name 6159) and add it to 10000g of cyclohexane. Adjust the temperature to 50℃ and stir thoroughly at 1500rpm for 30 minutes to prepare a solution in which the weight of SEBS is 20wt% of the weight of the organic solvent.

[0183] Take the SEBS solution and the organic suspension of treated barium sulfate, and place them in containers where the liquid outflow rate is regulated by pressure. Connect the outlets of the two containers with a T-connector to allow the liquids in the two containers to merge and flow further down. Connect a container below the outlet of the pipeline, and place water in the container to keep it boiling. Connect a pumping device above the container to collect the volatile solvent for reuse.

[0184] First, the SEBS solution was placed in the first container, and then the untreated barium sulfate cyclohexane suspension was placed in the second container. The outflow rates of the two containers were adjusted to 1.68:1. After the two solutions were mixed by impact, they fell into boiling water below, where the solvent was removed by boiling, and the mixture coagulated to obtain SEBS-loaded barium sulfate masterbatch. The collected SEBS-loaded barium sulfate masterbatch particles were placed in a 70°C oven and left to dry completely for 24 hours. Finally, a masterbatch with a barium sulfate loading of 100 wt% SEBS was obtained, designated as Barium Sulfate Masterbatch 15# (that is, in Barium Sulfate Masterbatch 15#, SEBS and barium sulfate each account for 50% by weight).

[0185] According to the formulas shown in Table 7, based on a total of 1000g of material for each formula, weigh out the raw materials of the four components, add the four raw materials to the low-speed mixer in sequence, and mix at 150rpm for 2 minutes to obtain the four blended mixtures.

[0186] Table 7

[0187]

[0188] A twin-screw extruder with a length-to-diameter ratio of 52:1 was selected. The screw was divided into 13 zones. The vacuum extraction pressure in the metering section was set to -0.90 MPa. The temperatures of each screw section were set to 135℃, 195℃, 205℃, 210℃, 210℃, 205℃, 205℃, 200℃, 200℃, 200℃, 205℃, 210℃, and 215℃. The main extruder speed was set to 300 rpm. The mixed raw materials were added to the twin-screw extruder through the main feed port for melt blending. After pelleting, the corresponding barium sulfate-filled polyolefin elastomer material was obtained. The mechanical properties and permanent deformation characteristics of the obtained material were tested, and the results are shown in Table 8.

[0189] Table 8

[0190]

[0191] As can be seen from the table, compared to using barium sulfate that has only undergone surface treatment, the polyolefin elastomer materials prepared using the barium sulfate masterbatch developed in this invention exhibit superior mechanical properties and lower permanent deformation, which also means better material resilience. The performance advantages of samples using barium sulfate masterbatch become more pronounced with increasing barium sulfate loading. Compared to surface-treated barium sulfate, pre-dispersing barium sulfate in SEBS via solution blending to prepare the masterbatch further improves the dispersion effect of barium sulfate in the polymer components, significantly contributing to the improvement of material properties.

[0192] Example 7

[0193] Place a 2000ml flask in an oil bath, set the oil bath temperature to 160℃, seal the flask thoroughly, and connect the flask to a vacuum pump via a tubing. During heating, turn on the vacuum pump and gradually evacuate the flask to a vacuum. After the flask temperature reaches above 140℃, turn off the vacuum after 2 minutes. Then connect the flask to a nitrogen cylinder via a tubing, fill the flask with nitrogen, and wait for the container to cool to room temperature. Repeat the above process 3 times to complete the preparation of the reaction vessel.

[0194] Using a syringe, add 150g of mPEG with an average molecular weight of 200 to the prepared flask. Then, using the syringe, add 300g of THF as a solvent and shake repeatedly for 2 minutes to fully dissolve the mPEG. Inject 18g of sodium hydride into the flask and react for 1.6 hours in an oil bath at 24°C.

[0195] Prepare 75g of MMA and place it in a beaker. Then add 200g of THF to the beaker, ensuring the MMA and THF are thoroughly mixed to form a solution. Add the MMA solution from the beaker dropwise into a flask, maintaining the flask in an oil bath at 28°C for 1.8 hours. After the reaction time is reached, add methanol dropwise to the flask to terminate the reaction. Open the flask and collect the reaction product. Add the product to a rotary evaporator, remove the THF by vacuum distillation, wash with ethanol, and then distill again under vacuum. Centrifuge the obtained product to remove the solvent, yielding barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 300.

[0196] 6000g of barium sulfate powder with an average particle size of 200nm and no surface chemical treatment was taken and divided into three equal portions of 2000g each, placed in separate containers. 18000g of cyclohexane was added to each of the three containers. 240g of mPEG-MMA (theoretically, 400 molecular weight) was added to the first container; 240g of potassium dodecyl alcohol ether phosphate, a commonly used surfactant in inorganic powder modification, was added to the second container; and 240g of aminopropyltriethoxysilane (KH550), a commonly used silane coupling agent, was added to the third container. The containers were placed in a water bath at 55℃ and stirred at 1600rpm for 1.3 hours to obtain three barium sulfate cyclohexane suspensions with different surface treatments.

[0197] Take 6000g of SEBS powder with brand name CH1320, add it to 24000g of cyclohexane, adjust the temperature to 50℃, and stir thoroughly at 1800rpm for 32 minutes to prepare a solution in which the weight of SEBS is 25wt% of the weight of the organic solvent.

[0198] SEBS solution and three organic suspensions of barium sulfate after different treatments were placed in containers with liquid outflow rate regulated by pressure. The outlets of the two containers were connected by a T-junction to allow the liquids in the two containers to merge and flow further down. A container was connected below the outlet of the pipeline, and water kept at a boiling state was placed in the container. A pumping device was connected above the container to collect the volatile solvent for reuse.

[0199] The liquid outflow rates of the two containers were adjusted to 1:1.7. After the two solutions were mixed by impact, they fell into the boiling water below. The solvent was removed by boiling, and coagulation yielded three types of barium sulfate masterbatches loaded with SEBS and three different surface treatments, denoted as barium sulfate masterbatches 16-18#. Among them, 16# was barium sulfate masterbatch loaded with mPEG-MMA, 17# was barium sulfate masterbatch loaded with the traditional surfactant dodecyl alcohol ether phosphate potassium salt, and 18# was barium sulfate masterbatch loaded with the silane coupling agent aminopropyltriethoxysilane. The state of the masterbatch preparation process was observed and recorded in Table 9.

[0200] The collected SEBS-loaded barium sulfate masterbatch particles were placed in a 70℃ oven and left to dry completely for 16 hours. The weight loss of the three masterbatches was analyzed using a thermogravimetric analyzer. The residual amount of different barium sulfate masterbatches was determined when the temperature was increased from room temperature to 800℃ in a nitrogen atmosphere at a rate of 10℃ / min, and compared with the theoretical barium sulfate loading. The results are also recorded in Table 9.

[0201] Table 9

[0202]

[0203] As shown in Table 9, compared with traditional surfactants and silane coupling agents, barium sulfate with mPEG-MMA as a surface treatment aid has better solubility in SEBS solution, can be mixed into SEBS solution more quickly and thoroughly, and is still well retained in SEBS component during subsequent solvent removal by boiling water. As a result, the barium sulfate loading in the corresponding SEBS masterbatch is basically consistent with the design amount.

[0204] According to the formula shown in Table 10, weigh 2000g of raw materials, add the raw materials to a low-speed mixer in sequence, and mix at 150rpm for 2 minutes to obtain a well-blended mixture.

[0205] Table 10

[0206] Raw material grade Masterbatch Formula 8 Barium sulfate masterbatch #16 50 SBS YH-792 10 POE 565 10 HDPE L501 30

[0207] A twin-screw extruder with a length-to-diameter ratio of 56:1 was selected. The screw was divided into 14 zones. The vacuum extraction pressure in the metering section was set to -0.90 MPa. The temperatures of each screw section were set to 130℃, 190℃, 200℃, 200℃, 210℃, 210℃, 200℃, 200℃, 205℃, 205℃, 210℃, 210℃, 210℃, and 220℃. The main extruder speed was set to 300 rpm. The mixed raw materials were fed into the twin-screw extruder through the main feed port for melt blending. After pelleting, the corresponding barium sulfate-filled polyolefin elastomer material was obtained. After hot pressing, the material was observed using a scanning electron microscope.

[0208] The results are attached. Figure 2 As shown, a large number of particles of hundreds of nanometers are uniformly distributed on the material surface. This directly illustrates the effect of using mPEG-MMA to treat barium sulfate surface and then preparing masterbatch on improving the dispersibility of barium sulfate in polyolefin elastomers.

[0209] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A SEBS-supported barium sulfate masterbatch, characterized in that, The product includes SEBS, barium sulfate, and barium sulfate surface treatment additives, wherein the weight ratio of SEBS to barium sulfate is 1:0.2-1.5, and the amount of barium sulfate surface treatment additives used is 2-15 wt% of the weight of barium sulfate powder. The barium sulfate surface treatment aid comprises a block copolymer of polyethylene glycol monomethyl ether and methyl methacrylate, wherein the molar ratio of polyethylene glycol monomethyl ether to methyl methacrylate is 1:1-4, and the theoretical molecular weight of the barium sulfate surface treatment aid is 300-600.

2. The SEBS-supported barium sulfate masterbatch according to claim 1, characterized in that, In the block copolymer, the average number of repeating units of polyethylene glycol monomethyl ether is 4-5, and the number of repeating units of methyl methacrylate is 1-4.

3. A method for preparing SEBS-supported barium sulfate masterbatch as described in claim 1 or 2, characterized in that, include: (1) Preparation of barium sulfate surface treatment additive; (2) Take barium sulfate powder, add it to an organic solvent, then add the barium sulfate surface treatment additive, stir and mix to obtain a surface-treated barium sulfate organic suspension; (3) Add SEBS to an organic solvent, stir and mix to prepare an SEBS solution; (4) The SEBS solution and the surface-treated barium sulfate organic suspension are placed in containers respectively, and the liquid outflow rate of the two containers can be adjusted. After the SEBS solution and the surface-treated barium sulfate organic suspension flow out of the containers and merge, they enter boiling water to remove the solvent, coagulate to obtain masterbatch, and dry to obtain SEBS-loaded barium sulfate masterbatch.

4. The preparation method according to claim 3, characterized in that, In step (1), the preparation method of the barium sulfate surface treatment aid includes: 1) Heat the container and evacuate it, then fill it with inert gas and allow the container to cool to room temperature; 2) Maintain an inert gas environment, add polyethylene glycol monomethyl ether to the container, then add solvent and shake to dissolve it; 3) Add sodium hydride or potassium hydride to the container to carry out the reaction; 4) Mix methyl methacrylate with a solvent to form a solution, and add the solution dropwise into a container to carry out the reaction; 5) Add methanol dropwise into the container to terminate the reaction and collect the reaction product; 6) Remove the solvent from the reaction product to obtain barium sulfate surface treatment aid mPEG-MMA.

5. The preparation method according to claim 4, characterized in that, In step 1), heat to 100-180℃ and evacuate.

6. The preparation method according to claim 4, characterized in that, In step 2), the weight of the added solvent is 2-4 times the weight of polyethylene glycol monomethyl ether.

7. The preparation method according to claim 4, characterized in that, In step 2), the solvent is tetrahydrofuran.

8. The preparation method according to claim 4, characterized in that, In step 2), the average molecular weight of the polyethylene glycol monomethyl ether is 200.

9. The preparation method according to claim 4, characterized in that, In step 3), the molar ratio of sodium hydride or potassium hydride to polyethylene glycol monomethyl ether is 1:

1.

10. The preparation method according to claim 4, characterized in that, In step 3), sodium hydride is used.

11. The preparation method according to claim 4, characterized in that, In step 3), the reaction is carried out at 20-30℃ for 1-3 hours.

12. The preparation method according to any one of claims 4-11, characterized in that, In step 4), the molar ratio of polyethylene glycol monomethyl ether to methyl methacrylate is 1:1-4.

13. The preparation method according to any one of claims 4-11, characterized in that, In step 4), the weight of the solvent in the solution is 2-4 times the weight of methyl methacrylate.

14. The preparation method according to any one of claims 4-11, characterized in that, In step 4), the solvent is selected from tetrahydrofuran.

15. The preparation method according to any one of claims 4-11, characterized in that, In step 4), maintain a temperature of 20-30°C and continue the reaction for at least 2 hours.

16. The preparation method according to claim 15, characterized in that, In step 4), the reaction continues for 2-4 hours.

17. The preparation method according to claim 3, characterized in that, In step (2), the reaction is stirred at 45-60℃ for 1-2 hours.

18. The preparation method according to claim 3, characterized in that, In step (2), the weight of the barium sulfate powder is 8-20 wt% of the weight of the organic solvent.

19. The preparation method according to claim 3, characterized in that, In step (2), the amount of barium sulfate surface treatment additive added is 2-15 wt% of the weight of barium sulfate.

20. The preparation method according to claim 3, characterized in that, In step (2), the barium sulfate powder is not subjected to any surface chemical treatment and has an average particle size of 100-400 nm.

21. The preparation method according to claim 3, characterized in that, In step (2), the stirring speed is 500-2000 rpm.

22. The preparation method according to claim 3, characterized in that, In step (2), the organic solvent is cyclohexane.

23. The preparation method according to claim 3, characterized in that, In step (3), stir thoroughly for 20-40 minutes at 40-60℃.

24. The preparation method according to claim 3, characterized in that, In step (3), the weight of the SEBS is 10-25 wt% of the weight of the organic solvent.

25. The preparation method according to claim 3, characterized in that, In step (3), the stirring speed is 500-2000 rpm.

26. The preparation method according to claim 3, characterized in that, In step (3), the organic solvent is cyclohexane.

27. A barium sulfate-filled polyolefin elastomer material, characterized in that, include: The SEBS-loaded barium sulfate masterbatch as described in claim 1 or 2 contains 10-75 wt% SEBS, 0-80 wt% SBS, 0-90 wt% POE, 0-45 wt% PP, and 0-45 wt% PE, including the SEBS contained in the SEBS-loaded barium sulfate masterbatch, and the sum of the amounts of SBS, SEBS, and POE is 50-98 wt%.

28. A method for preparing a barium sulfate-filled polyolefin elastomer material as described in claim 27, characterized in that, include: Mix at least one of SEBS, SBS, and POE with at least one of PP, PE, and SEBS-loaded barium sulfate masterbatch; Then, it is melt-extruded through a twin-screw extruder, pelletized, and barium sulfate-filled polyolefin elastomer material is obtained.

29. The preparation method according to claim 28, characterized in that, The temperature of each section of the twin-screw extruder is set in the range of 130-230℃, and the main extruder speed is set in the range of 200-400rpm.

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