SEBS-loaded barium sulfate master batch, preparation method and barium sulfate-filled polyolefin elastomer material

Abstract

The invention discloses an SEBS-loaded barium sulfate master batch, a preparation method and a barium sulfate-filled polyolefin elastomer material, the master batch comprises SEBS, barium sulfate and a barium sulfate surface treatment aid, the weight ratio of SEBS to barium sulfate is 1: 0.2-1.5, and the use amount of the barium sulfate surface treatment aid is 2-15 wt% of the weight of barium sulfate powder; the barium sulfate surface treatment auxiliary agent comprises a block copolymer composed of polyethylene glycol monomethyl ether and methyl methacrylate, 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 auxiliary agent is 300-600. According to the invention, the barium sulfate is subjected to surface treatment in the solution, and the continuous preparation of the SEBS-loaded barium sulfate master batch is realized through the continuous convective mixing of the barium sulfate suspension and the SEBS solution and the continuous removal of the mixed solvent; the master batch can be applied to polyolefin elastomers, and modification of the overall performance of a barium sulfate filled polyolefin elastomer material is achieved.

Description

Technical Field

[0001] The invention belongs to the field of polymer composite materials, and in particular relates to a SEBS-loaded barium sulfate masterbatch, a preparation method and a barium sulfate-filled polyolefin elastomer material. Background Art

[0002] Polyolefin elastomer is a polymer material that has the characteristics of both rubber and thermoplastics, showing high elasticity of rubber at room temperature and being able to be plasticized and formed at high temperature. 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 connected to form a unique microphase separation structure, which gives SEBS excellent elasticity and thermoplasticity, making it a typical polyolefin elastomer. Because of its good heat resistance, weather resistance and aging resistance, SEBS is used as the main raw material directly for the production and processing of final products in the fields of automotive parts, medical equipment, sports equipment, etc. However, the production cost of SEBS is relatively high, and in some specific application scenarios, its performance may still not meet the actual needs. Therefore, by combining SEBS with other polyolefin components, inorganic filler components and functional components through physical blending, a polyolefin elastomer that better meets the actual use needs can be prepared.

[0003] On the basis of SEBS, rigid polyolefin components such as polyethylene (PE) and polypropylene (PP) can be introduced through blending, or elastic components with different structural characteristics such as ethylene propylene diene monomer random copolymer (EPDM) and ethylene / α-olefin copolymer (POE) can be added to form polyolefin elastomer materials with a wider range of performance. In addition, inorganic filler components can be added to the broken polyolefin components through blending, thereby effectively improving the rigidity, hardness and wear resistance of thermoplastic elastomers, while improving the thermal properties of polyolefin elastomers, and effectively controlling the overall cost of materials.

[0004] Barium sulfate is a typical inorganic component. Its non-toxic, odorless and chemically stable properties make it particularly suitable as a filling component of medical polyolefin elastomer materials and is added through blending. More importantly, due to its high density, high refractive index, good hiding power and electromagnetic shielding properties, the composite material of barium sulfate and polyolefin elastomer can be used to manufacture various medical consumables such as stents and catheters. These consumables have good development effects under X-rays and are clearly visible in the image, which helps doctors accurately place and operate these consumables during surgery or treatment.

[0005] However, as a typical inorganic substance, barium sulfate has a large number of hydroxyl groups on its surface, which makes it highly active and polar, and has a large difference in chemical properties from polyolefin components. When it is directly filled into the polyolefin component, barium sulfate has a strong tendency to self-aggregate, and the filling process is very difficult. It is also difficult for barium sulfate to be evenly filled and dispersed in polyolefin. Therefore, in industrial preparation, it is difficult to achieve uniform filling and dispersion of untreated barium sulfate in polyolefin using only a screw extruder for extrusion blending. Similarly, after untreated barium sulfate is forcibly filled into the polyolefin component, it is also easy to precipitate significantly on the surface of the material. In this case, the mechanical properties and development effects of the corresponding materials are not ideal, and it is difficult to meet the material needs of medical products. In order to achieve efficient filling of barium sulfate in polyolefin and prepare high-performance composite materials, barium sulfate is usually surface treated and pre-dispersed in polyolefin to form a masterbatch.

[0006] In the traditional barium sulfate surface treatment method, a surface treatment additive is usually used and fully mixed with barium sulfate, and this process is often carried out in a stirring and mixing device. There are many problems in this mixing process: first, barium sulfate is easy to fly during the mixing process and cause dust pollution; second, the fluidity of the surface additive after contact with barium sulfate during mixing is limited, and the efficiency of surface treatment is not high enough.

[0007] The method of using surface-treated barium sulfate to blend with polyolefin components to form masterbatches is currently divided into two categories: melt blending and solution blending. Among them, melt blending is to use an internal mixer or an extruder as equipment, and by heating, the polyolefin components are in a molten state, and the barium sulfate is mixed and added. This method consumes a lot of energy, and it is difficult to complete the addition of barium sulfate with a high filling ratio. The dust pollution during the mixing process is also relatively serious. Solution blending is to make the polyolefin component in the form of a solution, then add the surface-treated barium sulfate thereto, mix the two by mechanical stirring, and finally remove the solvent to obtain a polyolefin-loaded barium sulfate masterbatch. Solution blending solves the problems existing in melt blending, but there are also problems such as the blending process is time-consuming, the masterbatch is not continuously and equally produced, and the processing process is discontinuous, and the industrial production efficiency is not ideal.

[0008] In order to further optimize the effect of solution blending in preparing polyolefin-loaded barium sulfate masterbatch and improve its yield, it is very important to develop a method that enables continuous production of masterbatch, matches the industrial assembly line production process, and ensures that the masterbatch meets the needs 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 to be solved by the present invention is to overcome the deficiencies of the prior art, and provide a SEBS-loaded barium sulfate masterbatch, a preparation method, and a barium sulfate-filled polyolefin elastomer material. The present invention develops an auxiliary agent that can be fully combined on the surface of barium sulfate in a solution and can overcome the difficult compatibility of barium sulfate with polymers through the design of a barium sulfate surface treatment auxiliary agent, and further realizes surface treatment of barium sulfate in a solution to obtain an organic suspension of barium sulfate. On this basis, the continuous preparation of SEBS-loaded barium sulfate masterbatch is achieved through continuous convection mixing of the barium sulfate suspension and the SEBS solution, and continuous removal of the mixed solvent. The masterbatch can be applied in polyolefin elastomers to achieve the modification of the overall performance of barium sulfate-filled polyolefin elastomer materials.

[0011] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0012] The present invention first designs a new and efficient barium sulfate surface treatment auxiliary agent, which can fully coat barium sulfate, significantly change the hydrophilic and high polarity characteristics of the barium sulfate surface, improve the binding of barium sulfate with polyolefin components, and meet the needs of surface treatment of barium sulfate in solution. Furthermore, the present invention uses a typical polyolefin elastomer SEBS that can be dissolved in organic solvents as a polymer component, and adopts a method of surface treatment of barium sulfate in liquid phase, thereby avoiding the low efficiency and dust pollution in the traditional barium sulfate surface treatment process; at the same time, the modified barium sulfate suspension and SEBS solution are used in an impact convection manner to achieve full mixing of the two, thereby solving the problem of discontinuous masterbatch output during the solution blending process. Finally, after the mixing is completed, the product is put into high-temperature boiling water to evaporate and remove the organic solvent, and is collected and reused to provide a guarantee for the continuity and low cost of the production process. Based on the preparation of SEBS-loaded barium sulfate masterbatch using the above method, polyolefin elastomer materials with various properties can be derived.

[0013] More specifically, the present invention first prepares a mPEG-MMA block copolymer composed of polyethylene glycol monomethyl ether (mPEG) and methyl methacrylate (MMA) by oxyanion polymerization. In combination with the characteristics of the auxiliary agent, a method of adding barium sulfate to cyclohexane and treating it with mPEG-MMA is developed, thereby obtaining an organic suspension of barium sulfate after surface treatment. As a barium sulfate surface treatment auxiliary agent, mPEG-MMA is fully combined on the surface of barium sulfate, overcoming the characteristics that barium sulfate is difficult to be compatible with polymers, so that the organic suspension of barium sulfate after surface treatment can fully complete the interlacing and combination of barium sulfate and polyolefin elastomer components after mixing and contacting with SEBS solution, and achieve highly uniform dispersion. Further, the present invention places the organic suspension and SEBS solution in two containers, adjusts the flow rate, realizes the convergence of the two liquids in proportion, and combines the flow impact to achieve mixing, and prepares a SEBS-loaded barium sulfate masterbatch by dropping into boiling water to remove the solvent, thereby realizing the continuous preparation of the masterbatch, and can ensure that the barium sulfate in the masterbatch is fully loaded and uniformly dispersed. The present invention also clarifies the method for applying the corresponding masterbatch to the preparation of barium sulfate-filled polyolefin elastomer materials through conventional blending. Through verification, it can be confirmed that mPEG-MMA is successfully synthesized and prepared according to the expected structure, and the designed method can fully combine with barium sulfate and improve the surface characteristics of barium sulfate. The SEBS-loaded barium sulfate masterbatch is also successfully prepared, and the loading amount of barium sulfate in the masterbatch is basically consistent with the design, and the barium sulfate is pre-dispersed. Further comparison confirms that the polyolefin composite material added with the SEBS-loaded barium sulfate masterbatch prepared by the method described in the present invention has good mechanical properties and elasticity. The preparation process of the SEBS-loaded barium sulfate masterbatch described in the present invention is simple and easy, and the preparation process is carried out continuously. The obtained masterbatch can also be prepared by conventional twin-screw melt extrusion and compounding with polyolefin elastomer to obtain the corresponding elastomer composite material, which is easy to realize continuous industrial production conversion as a whole.

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

[0016] The mPEG-MMA of the present invention is a block copolymer of ethylene glycol and acrylate, wherein the ester group can react with the hydroxyl group on the surface of barium sulfate, so as to promote mPEG-MMA to fully adhere to the surface of barium sulfate and realize the modification of barium sulfate. Meanwhile, the polyether structure in the polyethylene glycol segment can also be combined with the hydroxyl group on the surface of barium sulfate in the form of hydrogen bond, thereby realizing the coating of the surface treatment auxiliary agent mPEG-MMA on the surface of barium sulfate, minimizing the hydrophilic group exposed on the surface of barium sulfate, improving the affinity of barium sulfate and polymer parts, and reducing its self-aggregation tendency. More importantly, in an organic solution, the feature that mPEG-MMA has a large amount of polyether structures can also promote it to aggregate at the suspended barium sulfate particles under the action of polarity, thereby providing a basis for realizing the surface treatment of barium sulfate in an organic solution.

[0017] The present invention obtains a barium sulfate surface treatment auxiliary agent of expected molecular weight by controlling the addition ratio of polyethylene glycol monomethyl ether mPEG and methyl methacrylate MMA. The mPEG-MMA block copolymer of the present invention has a specific repeating unit structure and a narrow relative molecular mass distribution. Using mPEG-MMA in combination with specific conditions, it is possible to achieve surface treatment of barium sulfate in an organic solvent. Barium sulfate can be fully combined with mPEG-MMA, and the hydrophilicity of barium sulfate after surface treatment is significantly reduced, so that it can fully achieve interlaced combination of barium sulfate and polyolefin elastomer components in the solution, and achieve uniform dispersion of barium sulfate in the SEBS component, providing a basis for the preparation of SEBS loaded masterbatch. After barium sulfate is surface treated with mPEG-MMA and loaded in SEBS to prepare a masterbatch, it can also significantly modify the overall performance of the corresponding filled polyolefin elastomer material, thereby improving the use effect of barium sulfate filled polyolefin elastomer material in different application scenarios.

[0018] In a second aspect, the present invention provides a method for preparing a barium sulfate surface treatment additive, comprising:

[0019] (1) heating and evacuating a container, then filling it with an inert gas, and cooling the container to room temperature;

[0020] (2) maintaining an inert gas environment, adding polyethylene glycol monomethyl ether into a container, then adding a solvent, and shaking to dissolve it;

[0021] (3) adding sodium hydride or potassium hydride into the container and reacting at 20-30° C. for 1-3 hours;

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

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

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

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

[0026] In a further embodiment, the inert gas may be a common inert gas, such as nitrogen.

[0027] As a more specific scheme, in step (1), the prepared container is fully sealed and connected to a vacuum device via a conduit. The container is heated to 100-180°C while being evacuated to a vacuum. The vacuum is then turned off, the conduit is connected to a nitrogen supply system, nitrogen is filled into the container, and the container is cooled to room temperature. The above operation is repeated three times.

[0028] This step is intended to fully remove oxygen, carbon dioxide, and moisture in the reaction space to prevent the above substances from destroying the ion initiator and causing the active center to be deactivated.

[0029] In a further embodiment, in step (2), the weight of the added solvent 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 scheme, in step (2), without destroying the nitrogen environment in the container, mPEG with an average molecular weight of 200 is added to the prepared container, and then tetrahydrofuran (THF) is added as a solvent at a weight of 2-4 times the weight of mPEG, and the mPEG is fully dissolved by shaking.

[0033] As a solvent, THF has low viscosity and high solubility, and can provide good fluidity. At the same time, THF has moderate polarity, which avoids the problems of initiator aggregation and low initiation efficiency. It is a necessary solvent for polar monomers to carry out oxyanion polymerization.

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

[0039] Prepare MMA with 1-4 times the molar amount of mPEG in the container, that is, the weight of MMA is 0.5-2 times that of mPEG, and mix it with THF with 2-4 times the weight of MMA to form a solution. Add the solution dropwise into the container. Maintain the temperature at 20-30°C, continue the reaction for 2 hours, then drop methanol into the container to terminate the reaction and collect the reaction product.

[0040] This reaction is a typical oxyanion polymerization, using the oxyanion generated by sodium hydride in a polar solvent as an active center to initiate the polymerization of acrylate monomers. Combined with the use of this method, it is possible to synthesize mPEG-MMA block copolymers with specific structures and narrow relative molecular weight distribution at room temperature.

[0041] In a further scheme, in step (6), the collected product is subjected to vacuum distillation to remove THF, ethanol is added for washing, and then vacuum distillation is performed again, and finally the obtained product is centrifuged to remove the solvent, thereby obtaining the barium sulfate surface treatment additive mPEG-MMA.

[0042] According to the feed ratio and the average molecular weight of mPEG, in the mPEG-MMA segment synthesized by the present invention, the average number of repeating units of mPEG 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] In a third aspect, the present invention provides an application of the above-mentioned barium sulfate surface treatment auxiliary agent or the above-mentioned preparation method in the preparation of a surface-treated barium sulfate organic suspension.

[0044] In a fourth aspect, 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 it thoroughly to prepare an organic suspension, mix the barium sulfate surface treatment auxiliary agent described in the first aspect or the barium sulfate surface treatment auxiliary agent 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 8-20wt% of the weight of the organic solvent;

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

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

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

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

[0051] Take barium sulfate powder without any surface chemical treatment and with an average particle size of 100-400 nm, and weigh the organic solvent so that the weight of the barium sulfate powder is 8-20 wt % of the weight of the organic solvent.

[0052] Preferably, the solvent is cyclohexane.

[0053] Then, mPEG-MMA containing 2-15 wt% of the weight of barium sulfate is taken, and the barium sulfate, organic solvent and mPEG-MMA are mixed.

[0054] The mPEG-MMA designed in the present invention has a molecular weight between 300 and 600, a moderate molecular weight, and a low overall viscosity, and can 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°C and stirred at a speed of 500-2000rpm to allow the surface additive to react with the barium sulfate for 1-2 hours, and finally a surface-treated barium sulfate powder is obtained.

[0057] mPEG-MMA is a block copolymer of ethylene glycol and acrylate, in which the ester group can react with the hydroxyl group on the surface of barium sulfate at a certain temperature, so that mPEG-MMA can fully adhere to the surface of barium sulfate and achieve the modification of barium sulfate. At the same time, the polyether structure in the polyethylene glycol segment can also combine with the hydroxyl group on the surface of barium sulfate in the form of hydrogen bonds, thereby achieving the coating of the surface treatment additive mPEG-MMA on the surface of barium sulfate, minimizing the exposed hydrophilic groups on the surface of barium sulfate, improving the affinity of barium sulfate with polymer parts, and reducing its self-aggregation tendency. Due to the large proportion of polyether structure and polyester structure in mPEG-MMA, in the organic solution of barium sulfate, mPEG-MMA is more inclined to aggregate to the suspended barium sulfate particles under the induction of polarity, thereby achieving the surface treatment of barium sulfate in organic solution.

[0058] In a fifth aspect, 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 the barium sulfate surface treatment aid used is 2-15wt% of the weight of the barium sulfate powder;

[0059] The barium sulfate surface treatment auxiliary agent comprises a block copolymer composed of polyethylene glycol monomethyl ether and methyl methacrylate, 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 auxiliary agent 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] In a sixth aspect, the present invention provides a method for preparing a SEBS-loaded barium sulfate masterbatch, comprising:

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

[0063] (2) taking barium sulfate powder, adding it to an organic solvent, then adding the barium sulfate surface treatment additive, stirring and mixing, and obtaining a surface-treated barium sulfate organic suspension;

[0064] (3) adding SEBS to an organic solvent, stirring and mixing, and preparing a SEBS solution;

[0065] (4) placing a SEBS solution and a surface-treated barium sulfate organic suspension in containers respectively, wherein the liquid outflow rates of the two containers can be adjusted; after the SEBS solution and the surface-treated barium sulfate organic suspension flow out from the containers respectively and merge, they enter boiling water to remove the solvent, condense to obtain a master batch, and after drying, the SEBS-loaded barium sulfate master batch is obtained.

[0066] In step (1), the preparation method of the barium sulfate surface treatment auxiliary agent 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 into an organic solvent, and stirred 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 solution, in step (3), SEBS and organic solvent are weighed so that the weight of SEBS is 10-25wt% of the weight of the organic solvent, SEBS is added to the organic solvent, placed at 40-60°C, and stirred for 20-40 minutes to obtain a SEBS solution.

[0072] This step aims to control the conditions so that SEBS can be quickly dissolved in the organic solvent and avoid the volatilization of the organic solvent. At the same time, the viscosity of the SEBS solution needs to be controlled to maintain its good fluidity and stirring processability.

[0073] As an organic solvent, cyclohexane has a boiling point of 80.7°C and a solubility parameter of 7.2 (cal / cm 3 ) 1 / 2 The reason for choosing cyclohexane as the solvent of SEBS is that its solubility parameter is close to that of SEBS, and it can dissolve SEBS quickly and fully. Secondly, the boiling point of cyclohexane is significantly higher than the temperature of SEBS dissolution and barium sulfate surface treatment process, which can ensure that there will be no obvious evaporation loss of the solvent during the above operation, and maintain the stability of the operation process. At the same time, the boiling point of cyclohexane is significantly lower than that of water, which enables it to fully volatilize in the final evaporation and removal of the solvent operation, ensuring the preparation and formation of the masterbatch.

[0074] In step (4), the SEBS solution and the treated organic suspension of barium sulfate are placed in containers respectively for adjusting the liquid outflow rate by pressure;

[0075] Connect the outlets of the two containers with a tee pipe to allow the liquids in the two containers to merge and flow further downward;

[0076] A container is connected below the outlet of the pipeline, boiling water is placed in the container, and a pumping device is connected above the container to collect the volatile solvent for reuse;

[0077] Open the discharge ports of the two containers, adjust the liquid outflow rate of the two containers according to the designed barium sulfate loading amount, and after the two solutions are impacted and mixed, fall into the boiling water below, take away the solvent through boiling, and condense to obtain SEBS-loaded barium sulfate masterbatch;

[0078] Then the collected SEBS loaded barium sulfate masterbatch particles are placed in an oven at 70° C. for 16-32 hours, and after being completely dried, barium sulfate masterbatch particles are obtained.

[0079] In a further solution, in step (4), the outflow rate of the solutions 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 intersect, and the two liquids mix with each other after turbulent impact. Since the organic solvents of the two liquids are both cyclohexane, the liquids can quickly merge together. The affinity between the surface-treated barium sulfate and the organic polymer SEBS is also significantly improved. Therefore, during the mixing process of the two liquids generated by external convection, the surface-treated barium sulfate particles can easily enter the space between the SEBS molecular chains, achieving interlaced bonding. After the solvent cyclohexane is removed by volatilization, the barium sulfate is also preserved between the SEBS molecular chains, forming a SEBS-loaded barium sulfate masterbatch.

[0081] After the liquids in the two containers merge, they flow further down and are connected to a container below the outlet of the pipeline. Boiling water is placed in the container. After the mixed liquid enters the boiling water, the cyclohexane is continuously evaporated and removed because the temperature exceeds the boiling point. The remaining SEBS maintains the state of barium sulfate wrapped between the molecular chains, thereby realizing the preparation of the corresponding masterbatch.

[0082] In this process, since the liquid in the container loaded with barium sulfate organic suspension and SBES solution can be continuously replenished, the boiling water in the container below can keep boiling, the pumping equipment connected above the 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 achieve continuous preparation.

[0083] In a further solution, in step (4), the SEBS-loaded barium sulfate masterbatch can be used as a raw material for preparing a polyolefin elastomer after being fully 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 is 10-75wt%, SEBS is 0-80%, SBS is 0-90wt%, POE is 0-90wt%, PP is 0-45wt%, and PE is 0-45wt%. Including the SEBS used in the SEBS-loaded barium sulfate masterbatch, the sum of SBS, SEBS and POE is 50-98wt%.

[0086] The polyolefin elastomer material of the present invention comprises at least one polymer selected from butadiene-styrene copolymer (SBS), hydrogenated styrene-butadiene block copolymer (SEBS), 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 with similar materials prepared from common barium sulfate or surface-treated barium sulfate, the filled polyolefin elastomer material prepared by using SEBS-loaded barium sulfate masterbatch in the present invention has better mechanical properties and higher resilience.

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

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

[0090] In this process, all raw materials can be added into a low-speed mixer and mixed at a speed of 150 rpm for 2 minutes to obtain a blended mixture.

[0091] (2) Then, the product is melt-extruded through a twin-screw extruder and pelletized to obtain a barium sulfate-filled polyolefin elastomer material.

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

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

[0094] (1) The present 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 oxyanion polymerization, and applies it to the surface treatment of barium sulfate in an organic solvent, giving full play to its characteristics of low molecular weight and rich polyether structure and polyester structure, so that it can be quickly and evenly mixed with barium sulfate in the solvent, and the surface treatment of barium sulfate can be achieved under corresponding conditions, and the reaction method is simple and easy.

[0095] (2) The organic properties of mPEG-MMA are utilized to combine with the hydroxyl groups on the surface of barium sulfate and coat the surface of barium sulfate, thereby minimizing the exposed hydrophilic groups on the surface of barium sulfate and fully combining with the surface of barium sulfate, significantly overcoming the incompatibility of barium sulfate with polymers. After surface treatment, barium sulfate can penetrate into SEBS molecules in organic solvents, 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 impact of the SEBS solution and the barium sulfate suspension, and the barium sulfate masterbatch structure is constructed in an impact flow manner.

[0097] (4) The continuous flow of SBES solution and barium sulfate suspension, the continuous boiling of water, the continuous discharge of volatile solvents, and the continuous transmission of masterbatch products are combined to achieve the continuous preparation of SEBS-loaded barium sulfate masterbatch, and the masterbatch is further used to achieve the overall performance improvement of barium sulfate-filled polyolefin elastomer materials.

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

[0099] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings:

[0101] Figure 1 This is the infrared spectrum of the surface treated barium sulfate organic suspension prepared by the preparation method described in Example 3 after it is completely dried;

[0102] Figure 2 This is a scanning electron microscope (SEM) photograph 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 drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0104] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0105] The detection method adopted by the present invention is as follows:

[0106] 1. Average molecular weight determination:

[0107] The relative molecular weight of the sample was tested using a liquid chromatography-mass spectrometer. Chromatographic grade methanol was used as the mobile phase in the test, and the injection volume was controlled at 5 μL. The sample was ionized using the TIC anode source ion ionization mode, and the molecular weight of the sample was obtained by combining the multi-reaction level test method.

[0108] 2. Thermal gravimetric test:

[0109] Thermodynamic gravimetric analyzer (TGA) was used for thermal gravimetric determination. The sample was placed in a TGA special crucible. The test was carried out under nitrogen conditions. The test 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 tablet under a pressure of 10MPa. Use a contact angle tester to operate a micro syringe to drop water drops onto the surface of the silica tablet. Keep the first picture after complete dripping. The angle between the tangent line of the water drop surface and the sample in the picture is the contact angle.

[0112] 4. Fourier transform infrared spectroscopy analysis:

[0113] Take a small amount of completely dry powder to be tested and mix it with potassium bromide powder and grind it. Then put the mixed powder in a mold and press it into a thin sheet under a pressure of 10MPa. Use an infrared spectrometer to detect the pressed thin sheet. The test wave number is set to 400cm -1 Up to 4000cm -1 .

[0114] 5.Tensile strength:

[0115] The tensile properties are tested according to GB / T 528-2009. The sample is cut into a standard dumbbell-shaped sample with a thickness of 2±0.2mm and a working area width of 6mm. The sample is fixed on the fixture of the electronic tensile machine, and the extensometer is clamped on the sample working area. The extensometer is 25mm away and stretched at a rate of 500mm / min until the sample breaks. The tensile properties of the sample, such as tensile strength, 300% tensile stress and elongation at break, are recorded.

[0116] 6. Permanent deformation at break:

[0117] In the tensile strength test, a 25 mm long area is pre-marked on the working area of ​​the sample. When it is fixed on the fixture of the electronic tensile machine, the extensometer is clamped on the sample with the marked line aligned. After the sample is tensile broken, the broken sample is collected. After 24 hours, the sample is spliced ​​and the length of the area within the marked line is measured as L. According to R = (L-25) / 25×100%, the permanent deformation at break is calculated.

[0118] 7. Tear strength:

[0119] The tear strength is tested according to GB / T 529-2008. The sample is cut into a standard rectangular sample with a thickness of 2±0.2mm using a standard cutter. The sample is fixed on the fixture of the electronic tensile machine and the tear test is carried out at a rate of 500mm / min until the sample breaks. The tear strength of the sample is recorded.

[0120] Example 1

[0121] Place four 1000ml flasks in four oil baths, set the temperature of the oil bath to 180°C, fully seal the flasks, and connect the flasks to the vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate all four flasks to a vacuum. Turn off the vacuum 2 minutes after the flask temperature reaches above 160°C. Then connect the flasks to the nitrogen bottle in turn with a catheter, fill each flask with nitrogen, and wait for all flasks to cool to room temperature. Repeat the above process 3 times to complete the preparation of 4 reaction vessels.

[0122] Use a syringe to add 30g of mPEG with an average molecular weight of 200 to the prepared flask, then use a syringe to add 60g of THF as a solvent, and repeatedly shake for 2 minutes to fully dissolve the mPEG. Perform the same operation on 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 respectively, put them into 4 beakers No. 1-4, then add 60g, 120g, 180g and 240g of THF into the 4 beakers No. 1-4 respectively, and mix the MMA and THF in the 4 beakers thoroughly to form a solution. Add the MMA solution in beakers No. 1-4 to the 4 flasks respectively, and keep all the flasks in an oil bath at 20°C for 4 hours. After the reaction is over, methanol is added to the 4 flasks to terminate the reaction. After opening the flasks, collect the reaction products, add the products to the rotary evaporator in turn, remove THF by vacuum distillation, add ethanol for washing and vacuum distillation again. The obtained 4 products are centrifuged to remove the solvent, and the barium sulfate surface additive mPEG-MMA with theoretical molecular weights of 300, 400, 500 and 600 are obtained.

[0124] The four products were subjected to mass spectrometry detection using a liquid chromatography-mass spectrometer to analyze their average molecular weight and molecular structure, and the results are shown in Table 1. From the results, it can be seen that the main molecular composition of the obtained products is consistent with the design, and the measured average molecular weight is basically consistent with the theoretical molecular weight.

[0125] Table 1

[0126] Sample No. 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 temperature of the oil bath to 120°C, fully seal the flask, and connect the flask to a vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate the flask to a vacuum. 2 minutes after the flask temperature reaches above 100°C, turn off the vacuum. Then connect the flask to a nitrogen bottle with a catheter, 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] Use a syringe to add 80g of mPEG with an average molecular weight of 200 into the prepared flask, then use a syringe to add 320g of THF as a solvent, and repeatedly shake for 2 minutes to fully dissolve the mPEG. Then inject 20g of potassium hydride into the flask and react for 3 hours under oil bath conditions at 20°C.

[0130] Prepare 120g of MMA, put it in a beaker, and then add 240g of THF to the beaker to fully mix the MMA and THF in the beaker to form a solution. Add the MMA solution in the beaker dropwise into the flask, and keep the flask in an oil bath at 30°C for 2 hours. After the reaction is over, methanol is dropped into the flask to terminate the reaction. After opening the flask, collect the reaction product, add the product to a rotary evaporator, remove THF by vacuum distillation, add ethanol for washing, and then vacuum distill again. Centrifuge the obtained product to remove the solvent to obtain a barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 500.

[0131] Take 1000g of barium sulfate powder without any surface chemical treatment and with an average particle size of 400nm, divide it into 5 parts, each part is 200g, and add it to 5 containers, numbered 1-5. Add 2500g of cyclohexane to each of the 5 containers, and then add 4g, 8g, 14g, 20g, and 30g of the above mPEG-MMA with a theoretical molecular weight of 500 to containers 1-5 respectively. Place the container in a water bath, adjust the water bath temperature to 60°C, stir and react at a speed of 500rpm for 1 hour, and obtain 5 kinds of surface-treated barium sulfate cyclohexane suspensions, wherein the amount of the surface treatment auxiliary agent mPEG-MMA is 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, put them into a container, and use freeze-drying to remove the organic solvent cyclohexane to obtain five surface-treated barium sulfate powders, each of which is about 2.2 grams. Take approximately the same amount of untreated barium sulfate powder, and wrap the six barium sulfate powders with filter paper, use a Soxhlet extractor, use cyclohexane as a solvent, extract for 24 hours (about 15-20 minutes reflux once), and place the product after extraction in an oven, dry to constant weight at 70°C, and then perform thermal weight loss tests separately. According to the characteristics of barium sulfate powder, the weight loss range can be divided into two ranges: room temperature -120°C and 120-800°C. The weight loss in the former range is caused by the removal of adsorbed water, and the weight loss in the latter range is mainly caused by the removal of chemically bound water and the decomposition of the surface additives bound to barium sulfate. The corresponding results are shown in Table 2.

[0133] From the data in Table 2, it can be seen that as the amount of mPEG-MMA relative to barium sulfate increases, the weight loss of the corresponding barium sulfate sample in the range of 120-800°C increases, while the weight loss in the range of room temperature -120°C decreases. On the one hand, this shows that mPEG-MMA is fully and firmly combined with barium sulfate, and on the other hand, it also shows that the hydrophilicity of barium sulfate combined with mPEG-MMA is significantly reduced.

[0134] Table 2

[0135]

[0136] Example 3

[0137] Place a 500ml flask in an oil bath, set the temperature of the oil bath to 160°C, fully seal the flask, and connect the flask to a vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate the flask to a vacuum. 2 minutes after the flask temperature reaches above 150°C, turn off the vacuum. Then connect the flask to a nitrogen bottle with a catheter, 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.

[0138] Use a syringe to add 20g of mPEG with an average molecular weight of 200 into the prepared flask, then use a syringe to add 60g of THF as a solvent, and shake repeatedly for 2 minutes to fully dissolve the mPEG. Then 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, put it in a beaker, and then add 60g of THF to the beaker to fully mix the MMA and THF in the beaker to form a solution. Add the MMA solution in the beaker dropwise into the flask, and keep the flask in an oil bath at 25°C for 3 hours. After the reaction is over, methanol is dropped into the flask to terminate the reaction. After opening the flask, collect the reaction product, add the product to a rotary evaporator, remove THF by vacuum distillation, add ethanol for washing, and then vacuum distill again. Centrifuge the obtained product to remove the solvent to obtain a barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 400.

[0140] 100 g of barium sulfate powder without any surface chemical treatment and with an average particle size of 300 nm was taken and placed in a container. 500 g of cyclohexane was added to the container, and then 8 g of mPEG-MMA with a theoretical molecular weight of 400 was added to the container. The container was placed in a water bath, the water bath temperature was adjusted to 45°C, and the reaction was stirred at a speed of 2000 rpm for 2 hours to obtain a surface-treated barium sulfate cyclohexane suspension, in which the amount of the surface treatment auxiliary agent mPEG-MMA was 8 wt% 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 to obtain about 7.2g of surface-treated barium sulfate powder. Then, about the same amount of untreated barium sulfate powder was taken. The above two powders were subjected to Fourier transform infrared spectroscopy analysis and particle size detection, respectively. The obtained infrared spectra are shown in the attached figure. Figure 1The average particle size is shown in Table 3. Part of the treated barium sulfate powder was pressed into thin sheets at 15 MPa for water contact angle test. The untreated barium sulfate powder was treated in the same way for control test. The results are shown in Table 3.

[0142] Table 3

[0143] Sample No. Average particle size Water contact angle Untreated barium sulfate 307nm 33° Example 3 Surface Treatment of Barium Sulfate 304nm 71°

[0144] Result analysis:

[0145] Compare with Figure 1 The infrared spectra of barium sulfate powder with and without surface treatment show that the treated barium sulfate sample has a peak at 2850-2950cm in the infrared spectrum. -1 There are two obvious peaks in the range, which correspond to the peaks of methylene (-CH2-) and methyl (-CH3), which further shows that mPEG-MMA and barium sulfate can be fully combined under the surface treatment method of the present invention, so that barium sulfate has obvious organic properties. In terms of particle size and water contact, it can be found that the average particle size of barium sulfate does not change substantially before and after mPEG-MMA treatment, but the water contact angle is significantly improved, which shows that the surface treatment of barium sulfate with mPEG-MMA can significantly reduce the hydrophilicity of barium sulfate.

[0146] Example 4

[0147] Place a 2000ml flask in an oil bath, set the temperature of the oil bath to 150°C, fully seal the flask, and connect the flask to a vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate the flask to a vacuum. Turn off the vacuum 2 minutes after the flask temperature reaches above 130°C. Then connect the flask to a nitrogen bottle with a catheter, 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] Use a syringe to add 150g of mPEG with an average molecular weight of 200 into the prepared flask, then use a syringe to add 400g of THF as a solvent, and shake repeatedly for 2 minutes to fully dissolve the mPEG. Then inject 18g of sodium hydride into the flask and react in an oil bath at 30°C for 1.5 hours.

[0149] Prepare 75g of MMA, put it in a beaker, and then add 200g of THF to the beaker to fully mix the MMA and THF in the beaker to form a solution. Add the MMA solution in the beaker dropwise into the flask, and keep the flask in an oil bath at 25°C for 2.5 hours. After the reaction is over, methanol is dropped into the flask to terminate the reaction. After opening the flask, collect the reaction product, add the product to a rotary evaporator, remove THF by vacuum distillation, add ethanol for washing, and vacuum distill again. Centrifuge the obtained product to remove the solvent to obtain a barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 300.

[0150] 2000g of barium sulfate powder without any surface chemical treatment and with an average particle size of 200nm was taken and placed in a container. 15000g of cyclohexane was added to the container, and then 200g of the above mPEG-MMA with a theoretical molecular weight of 300 was added to the container. The container was placed in a water bath, the water bath temperature was adjusted to 55°C, and the reaction was stirred at a speed of 1000rpm for 1.5 hours to obtain a surface-treated barium sulfate cyclohexane suspension, in which the amount of the surface treatment auxiliary agent mPEG-MMA was 10wt% of the weight of the barium sulfate powder.

[0151] Then, 2000 g of barium sulfate powder without any surface chemical treatment and with an average particle size of 200 nm was placed in a container, and 15000 g of cyclohexane was added to the container. The container was placed in a water bath, the water bath temperature was adjusted to 55° C., and the reaction was stirred at a speed of 1000 rpm for 1.5 hours to obtain a cyclohexane suspension of barium sulfate without surface treatment.

[0152] Take 1000g of SEBS powder with brand number 6159, add it to 10000g of cyclohexane, adjust the temperature to 40°C, stir it at a speed of 2000rpm for 40 minutes, and prepare a solution in which the weight of SEBS is 10wt% of the weight of the organic solvent.

[0153] Take SEBS solution and untreated barium sulfate organic suspension, respectively place them in containers that can adjust the liquid outflow rate by pressure, connect the outlets of the two containers with a three-way pipe, so that the liquids in the two containers can flow further after merging, connect a container below the pipeline outlet, place boiling water in the container, and 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 impact mixed, they fell into the boiling water below, and the solvent was taken away by boiling. Five SEBS-loaded barium sulfate masterbatches without surface treatment were condensed to obtain masterbatches 1-5#. The status 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 be 1:1.56, 1:3.13, 1:3.82, 1:7.82, and 1:11.73, respectively. After the two solutions were impact mixed, they fell into the boiling water below, and the solvent was taken away by boiling. Five kinds of SEBS-loaded surface-treated barium sulfate masterbatches were condensed and recorded as masterbatches 6-10#. The status of the masterbatch preparation process was observed and recorded in Table 4.

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

[0157] Table 4

[0158]

[0159] Result analysis:

[0160] As can be seen from Table 4, the surface-treated barium sulfate has better solubility in the solution, can be mixed into the SEBS solution more quickly and more fully, and is still well retained in the SEBS component during the subsequent boiling water desolventization process, so that the corresponding barium sulfate loading in the SEBS masterbatch is basically consistent with the designed amount. However, it is relatively difficult for untreated barium sulfate to enter the SEBS solution, it is not easy to disperse in the SEBS solution, and it is easier to enter the water during the boiling water desolventization process, resulting in the final barium sulfate content in the SEBS masterbatch being significantly lower than the theoretical value.

[0161] Example 5

[0162] Place a 4000ml flask in an oil bath, set the temperature of the oil bath to 160°C, fully seal the flask, and connect the flask to a vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate the flask to a vacuum. 2 minutes after the flask temperature reaches above 140°C, turn off the vacuum. Then connect the flask to a nitrogen bottle with a catheter, 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.

[0163] 300 g of mPEG with an average molecular weight of 200 was added to the prepared flask using a syringe, and then 800 g of THF was added as a solvent using a syringe, and the mixture was shaken repeatedly for 2 minutes to fully dissolve the mPEG. 36 g of sodium hydride was injected into the flask, and the mixture was reacted in an oil bath at 20°C for 2.5 hours.

[0164] Prepare 450g of MMA, put it in a beaker, and then add 1000g of THF to the beaker to fully mix the MMA and THF in the beaker to form a solution. Add the MMA solution in the beaker dropwise into the flask, and keep the flask in an oil bath at 25°C for 3.5 hours. After the reaction is over, methanol is dropped into the flask to terminate the reaction. After opening the flask, collect the reaction product, add the product to a rotary evaporator, remove THF by vacuum distillation, add ethanol for washing, and vacuum distill again. Centrifuge the obtained product to remove the solvent to obtain a barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 500.

[0165] 10000g of barium sulfate powder without any surface chemical treatment and with an average particle size of 300nm was taken and placed in a container. 60000g of cyclohexane was added to the container, and then 500g of mPEG-MMA with a theoretical molecular weight of 500 was added to the container. The container was placed in a water bath, the water bath temperature was adjusted to 50°C, and the reaction was stirred at a speed of 1500rpm for 1.6 hours to obtain a surface-treated barium sulfate cyclohexane suspension, in which the amount of the surface treatment auxiliary agent mPEG-MMA was 5wt% of the weight of the barium sulfate powder.

[0166] Take 2000 g of SEBS particles with a brand number of 8245D, add it to 4000 g of cyclohexane, adjust the temperature to 60° C., stir it at a speed of 500 rpm for 20 minutes, and prepare a solution in which the weight of SEBS is 25 wt % of the weight of the organic solvent.

[0167] Take SEBS solution and treated barium sulfate organic suspension, respectively place them in containers that can adjust the liquid outflow rate by pressure, connect the outlets of the two containers with a three-way pipe, so that the liquids in the two containers can flow further after merging, connect a container below the pipeline outlet, place boiling water in the container, and 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 be 1:0.47, 1:0.94, 1:1.41, and 1:1.88, respectively. After the two solutions were impacted and mixed, they fell into the boiling water below, and the solvent was taken away by boiling, and condensed to obtain 4 kinds of SEBS-loaded barium sulfate master batches. The collected SEBS-loaded barium sulfate master batches were placed in an oven at 70°C for 32 hours and completely dried. Finally, 4 kinds of master batches with barium sulfate loading of 20wt%, 40wt%, 60wt%, and 80wt% of the weight of SEBS were obtained, which were recorded as barium sulfate master batches 11-14#.

[0169] According to the formula shown in Table 5, a total of 2000 g of materials were used for each formula, and the raw materials of 8 components were weighed. The 8 raw materials were added into a low-speed mixer in sequence, and mixed at a speed of 150 rpm for 2 minutes to obtain 8 blended mixtures.

[0170] Table 5

[0171]

[0172]

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

[0174] Table 6

[0175]

[0176] As can be seen from Table 6, compared with the use of untreated barium sulfate, the polyolefin elastomer material prepared by using the SEBS-loaded barium sulfate masterbatch developed by the present invention has better mechanical properties and lower permanent deformation of the material, which also means that the material has better resilience. As the amount of barium sulfate filling increases, the performance advantage of the sample with the barium sulfate masterbatch is more obvious.

[0177] Example 6

[0178] Place a 5000ml flask in an oil bath, set the temperature of the oil bath to 170°C, fully seal the flask, and connect the flask to a vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate the flask to a vacuum. 2 minutes after the flask temperature reaches above 150°C, turn off the vacuum. Then connect the flask to a nitrogen bottle with a catheter, 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] Use a syringe to add 400g of mPEG with an average molecular weight of 200 into the prepared flask, then use a syringe to add 1000g of THF as a solvent, and shake repeatedly for 2 minutes to fully dissolve the mPEG. Then 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, put it in a beaker, and then add 1000g of THF to the beaker to fully mix the MMA and THF in the beaker to form a solution. Add the MMA solution in the beaker dropwise into the flask, and keep the flask in an oil bath at 23°C for 3.5 hours. After the reaction is over, methanol is dropped into the flask to terminate the reaction. After opening the flask, collect the reaction product, add the product to a rotary evaporator, remove THF by vacuum distillation, add ethanol for washing, and vacuum distill again. Centrifuge the obtained product to remove the solvent to obtain a barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 500.

[0181] 10000g of barium sulfate powder without any surface chemical treatment and with an average particle size of 300nm is taken and placed in a container. 90000g of cyclohexane is added to the container, and then 800g of mPEG-MMA with a theoretical molecular weight of 400 is added to the container. The container is placed in a water bath, the water bath temperature is adjusted to 55°C, and the reaction is stirred at a speed of 1200rpm for 1.2 hours to obtain a surface-treated barium sulfate cyclohexane suspension, in which the amount of the surface treatment auxiliary agent mPEG-MMA is 8wt% of the weight of the barium sulfate powder. 40000g of the surface-treated barium sulfate cyclohexane suspension is taken and placed in a container, and the organic solvent cyclohexane is removed by freeze drying to obtain about 4285g of surface-treated barium sulfate powder.

[0182] Take 2000g of SEBS powder with brand number 6159, add it to 10000g of cyclohexane, adjust the temperature to 50°C, stir it at a speed of 1500rpm for 30 minutes, and prepare a solution in which the weight of SEBS is 20wt% of the weight of the organic solvent.

[0183] Take SEBS solution and treated barium sulfate organic suspension, respectively place them in containers that can adjust the liquid outflow rate by pressure, connect the outlets of the two containers with a three-way pipe, so that the liquids in the two containers can flow further after merging, connect a container below the pipeline outlet, place boiling water in the container, and connect a pumping device above the container to collect the volatile solvent for reuse.

[0184] First, the SEBS solution is placed in the first container, and then the unsurface-treated barium sulfate cyclohexane suspension is placed in the second container. The liquid outflow rate of the two containers is adjusted to 1.68:1. After the two solutions are impacted and mixed, they fall into the boiling water below, and the solvent is taken away by boiling. SEBS-loaded barium sulfate masterbatch is condensed, and the collected SEBS-loaded barium sulfate masterbatch particles are placed in a 70°C oven for 24 hours to completely dry. Finally, a masterbatch with a barium sulfate loading of 100wt% of the weight of SEBS is obtained, which is recorded as barium sulfate masterbatch 15# (that is, in barium sulfate masterbatch 15#, the weight of SEBS and barium sulfate each accounts for 50%).

[0185] According to the formula shown in Table 7, a total of 1000 g of material was used for each formula, and the raw materials of the four components were weighed. The four raw materials of the four components were added into a low-speed mixer in sequence, and mixed at a speed of 150 rpm for 2 minutes to obtain four blended mixtures.

[0186] Table 7

[0187]

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

[0189] Table 8

[0190]

[0191] As can be seen from the table, compared with the use of barium sulfate that is only surface treated, the polyolefin elastomer material prepared using the barium sulfate masterbatch developed by the present invention has better mechanical properties and lower permanent deformation of the material, which also means that the material has better resilience. As the amount of barium sulfate filling increases, the performance advantage of the sample with the barium sulfate masterbatch is more obvious. Compared with the surface treated barium sulfate, the barium sulfate is pre-dispersed in SEBS by solution blending to prepare the masterbatch, which further improves the dispersion effect of barium sulfate in the polymer component and is significantly helpful for improving the material performance.

[0192] Example 7

[0193] Place a 2000ml flask in an oil bath, set the temperature of the oil bath to 160°C, fully seal the flask, and connect the flask to a vacuum pump with a catheter. During the heating process, turn on the vacuum pump and gradually evacuate the flask to a vacuum. 2 minutes after the flask temperature reaches above 140°C, turn off the vacuum. Then connect the flask to a nitrogen bottle with a catheter, 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] Use a syringe to add 150g of mPEG with an average molecular weight of 200 into the prepared flask, then use a syringe to add 300g of THF as a solvent, and repeatedly shake for 2 minutes to fully dissolve the mPEG. Then inject 18g of sodium hydride into the flask and react for 1.6 hours under oil bath conditions at 24°C.

[0195] Prepare 75g of MMA, put it in a beaker, and then add 200g of THF to the beaker to fully mix the MMA and THF in the beaker to form a solution. Add the MMA solution in the beaker dropwise into the flask, and keep the flask in an oil bath at 28°C for 1.8 hours. After the reaction is over, methanol is dropped into the flask to terminate the reaction. After opening the flask, collect the reaction product, add the product to a rotary evaporator, remove THF by vacuum distillation, add ethanol for washing, and vacuum distill again. Centrifuge the obtained product to remove the solvent to obtain a barium sulfate surface additive mPEG-MMA with a theoretical molecular weight of 300.

[0196] Take 6000g of barium sulfate powder without any surface chemical treatment and with an average particle size of 200nm, divide it into 3 parts, each part is 2000g, and put it into a container respectively. Add 18000g of cyclohexane into three containers respectively. Add 240g of mPEG-MMA with a theoretical molecular weight of 400 into the first container, add 240g of surfactant dodecyl alcohol ether phosphite potassium salt commonly used in inorganic powder modification into the second container, and add 240g of commonly used silane coupling agent aminopropyl triethoxysilane (KH550) into the third container. Place the container in a water bath, adjust the water bath temperature to 55°C, and stir the reaction at a speed of 1600rpm for 1.3 hours to obtain 3 kinds of barium sulfate cyclohexane suspensions with different surface treatments of additives.

[0197] 6000 g of SEBS powder of brand CH1320 was added to 24000 g of cyclohexane, the temperature was adjusted to 50° C., and the mixture was stirred at 1800 rpm for 32 minutes to prepare a solution in which the weight of SEBS was 25 wt % of the weight of the organic solvent.

[0198] Take SEBS solution and three kinds of organic suspensions of barium sulfate after different treatments, respectively place them in containers that can adjust the liquid outflow rate by pressure, connect the outlets of the two containers with a three-way pipe, so that the liquids in the two containers can flow further after merging, connect a container below the pipeline outlet, place boiling water in the container, and connect a pumping device above the container to collect the volatile solvent for reuse.

[0199] The liquid outflow rate of the two containers was adjusted to 1:1.7. After the two solutions were impact mixed, they fell into the boiling water below, and the solvent was taken away by boiling. Three kinds of SEBS loaded barium sulfate masterbatches with three different surface treatments were condensed, which were recorded as barium sulfate masterbatches 16-18#, among which 16# was barium sulfate masterbatch loaded with mPEG-MMA, 17# was barium sulfate masterbatch loaded with traditional surfactant potassium dodecyl alcohol ether phosphate, and 18# was barium sulfate masterbatch loaded with silane coupling agent aminopropyl triethoxysilane. The status of the masterbatch preparation process was observed and recorded in Table 9.

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

[0201] Table 9

[0202]

[0203] It can be seen from Table 9 that, compared with traditional surfactants and silane coupling agents, barium sulfate with mPEG-MMA as a surface treatment additive has better solubility in SEBS solution, can be mixed into the SEBS solution more quickly and more fully, and is still well retained in the SEBS component during the subsequent boiling water desolventizing process, thereby making the corresponding barium sulfate loading in the SEBS masterbatch basically consistent with the designed amount.

[0204] According to the formulation shown in Table 10, 2000 g of raw materials were weighed, and the raw materials were added into a low-speed mixer in sequence, and mixed at a speed of 150 rpm for 2 minutes to obtain a 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 an aspect ratio of 56:1 was selected, the screw was divided into 14 zones, the vacuum extraction pressure value of the metering section was set to -0.90 MPa, the temperature of each section of the screw was set to 130°C, 190°C, 200°C, 200°C, 210°C, 210°C, 200°C, 200°C, 205°C, 205°C, 210°C, 210°C, 210°C, 220°C, the main engine speed was set to 300rpm, the mixed raw materials were added to the twin-screw extruder from the main feed port for melt blending, and the corresponding barium sulfate filled polyolefin elastomer material was obtained after pelletizing. After the material was hot pressed, the material was observed by scanning electron microscope.

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

[0209] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the present invention can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A SEBS-loaded barium sulfate masterbatch, characterized in that: It comprises SEBS, barium sulfate and a barium sulfate surface treatment additive, wherein the weight ratio of SEBS to barium sulfate is 1:0.2-1.5, and the usage amount of the barium sulfate surface treatment additive is 2-15wt% of the weight of the barium sulfate powder; The barium sulfate surface treatment auxiliary agent comprises a block copolymer composed of polyethylene glycol monomethyl ether and methyl methacrylate, 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 auxiliary agent is 300-600.

2. The SEBS-loaded 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 a SEBS-loaded barium sulfate masterbatch as claimed in claim 1 or 2, characterized in that: include: (1) preparing barium sulfate surface treatment additive; (2) taking barium sulfate powder, adding it to an organic solvent, then adding the barium sulfate surface treatment additive, stirring and mixing, and obtaining a surface-treated barium sulfate organic suspension; (3) adding SEBS to an organic solvent, stirring and mixing, and preparing a SEBS solution; (4) placing a SEBS solution and a surface-treated barium sulfate organic suspension in containers respectively, wherein the liquid outflow rates of the two containers can be adjusted; after the SEBS solution and the surface-treated barium sulfate organic suspension flow out from the containers respectively and merge, they enter boiling water to remove the solvent, condense to obtain a master batch, and after drying, the SEBS-loaded barium sulfate master batch is obtained.

4. The preparation method according to claim 3, characterized in that: In step (1), the preparation method of the barium sulfate surface treatment auxiliary agent comprises: (1) heating and evacuating a container, then filling it with an inert gas, and cooling the container to room temperature; Preferably, heating to 100-180°C and evacuating; (2) maintaining an inert gas environment, adding polyethylene glycol monomethyl ether into a container, then adding a solvent, and shaking to dissolve it; (3) adding sodium hydride or potassium hydride into the container to react; Preferably, the reaction is carried out at 20-30° C. for 1-3 hours; (4) mixing methyl methacrylate and a solvent to form a solution, and adding the solution dropwise into a container to react; Preferably, the temperature is maintained at 20-30°C and the reaction is continued for at least 2 hours, more preferably 2-4 hours; (5) adding methanol dropwise into the container to terminate the reaction and collecting the reaction product; (6) removing the solvent from the reaction product to obtain the barium sulfate surface treatment additive mPEG-MMA.

5. 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; Preferably, in step (2), the solvent is tetrahydrofuran; Preferably, in step (2), the average molecular weight of the polyethylene glycol monomethyl ether is 200; Preferably, in step (3), the molar ratio of sodium hydride or potassium hydride to polyethylene glycol monomethyl ether is 1:1, preferably, sodium hydride is used; Preferably, in step (4), the molar ratio of polyethylene glycol monomethyl ether to methyl methacrylate is 1:1-4; Preferably, in step (4), the weight of the solvent in the solution is 2-4 times the weight of methyl methacrylate; Preferably, in step (4), the solvent is selected from tetrahydrofuran.

6. The preparation method according to claim 3, characterized in that: In step (2), stirring the reaction at 45-60° C. for 1-2 hours; Preferably, the weight of the barium sulfate powder is 8-20wt% of the weight of the organic solvent; Preferably, the amount of the barium sulfate surface treatment additive added is 2-15wt% of the weight of the barium sulfate; Preferably, the barium sulfate powder has not undergone any surface chemical treatment and has an average particle size of 100-400 nm; Preferably, the stirring speed is 500-2000rpm; Preferably, the organic solvent is cyclohexane.

7. The preparation method according to claim 3, characterized in that: In step (3), stirring at 40-60° C. for 20-40 minutes; Preferably, the weight of the SEBS is 10-25wt% of the weight of the organic solvent; Preferably, the stirring speed is 500-2000rpm; Preferably, the organic solvent is cyclohexane.

8. The preparation method according to claim 3, characterized in that: In step (4), in the obtained SEBS-loaded barium sulfate masterbatch, the weight ratio of SEBS to barium sulfate is 1:0.2-1.

5.

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

10. A method for preparing a barium sulfate filled polyolefin elastomer material as claimed in claim 9, characterized in that: include: Mixing at least one of SEBS, SBS and POE with at least one of PP and PE and SEBS-loaded barium sulfate masterbatch; Then, the barium sulfate-filled polyolefin elastomer material is obtained by melt extrusion through a twin-screw extruder and pelletization; Preferably, the temperature of each section of the twin-screw extruder is set to the range of 130-230°C, and the main engine speed is set to 200-400rpm.

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