A polyurethane batch and a method for its production

Abstract

The application relates to the technical field of graphene, and provides a polyurethane masterbatch and a preparation method thereof.The preparation method of the polyurethane masterbatch comprises the following steps: first, preparing a mixed solution of an oxidized graphene water solution and an aqueous polyurethane emulsion; then, adding a quaternary ammonium salt water solution into the mixed solution while stirring; then, breaking the emulsion to precipitate a product; and finally, washing, suction filtering and drying the product to obtain the polyurethane masterbatch.The preparation method of the polyurethane masterbatch has the advantages of low cost, non-toxicity and simple process.

Description

Technical Field

[0001] This invention relates to the field of graphene technology, and in particular to a polyurethane masterbatch and its preparation method. Background Technology

[0002] The masterbatch method refers to the preparation of a concentrated product during the processing of plastics and rubber by mixing a large amount of fillers, additives, and a small amount of carrier resin through methods such as compounding and internal mixing. This method facilitates filler addition, improves production efficiency, and avoids environmental pollution. The masterbatch method was initially used to prepare color masterbatches, preventing problems such as difficulty in pigment addition and excessive dust, and achieving uniform color in composite materials. Currently, the masterbatch method is gradually expanding to the field of functional masterbatches such as conductive masterbatches, flame-retardant masterbatches, and reinforcing masterbatches. The preparation methods of masterbatches have also expanded from compounding and internal mixing to in-situ blending, solution blending, and melt blending processes.

[0003] Graphene, as a multifunctional nanofiller with high electrical and thermal conductivity and high strength, has attracted widespread attention from researchers regarding the modification of graphene masterbatch and its preparation process. However, due to problems such as the scarcity of oxygen-containing functional groups on the surface of graphene, low inertness, and easy agglomeration, graphene exhibits poor direct dispersibility in most polymer materials.

[0004] In the field of polymer composites, preparation methods are mainly divided into melt blending, solution blending, and in-situ blending, with the composite dispersion effect improving in that order. However, solution blending and in-situ blending are rarely used for industrialization due to problems such as requiring large amounts of solvent, high production costs, and low efficiency. Typically, graphene is pretreated through methods such as surface grafting, coating, and intercalation. For example, silver intercalation of graphene allows silver nanoparticles to coat the graphene surface, reducing graphene agglomeration. Then, a screw extrusion process is used to disperse it in ABS melt to prepare a graphene conductive masterbatch. However, this method suffers from complex preparation processes and high costs. Although existing technologies also utilize electrostatic adsorption mechanisms to self-assemble graphene / carbon black composites and then fill them into thermoplastic resins, electrostatic adsorption makes it difficult to guarantee the effective intercalation of carbon black into graphene. Summary of the Invention

[0005] The present invention aims to solve the technical problems of complex polyurethane masterbatch processes and poor physical properties in the prior art.

[0006] To address the aforementioned technical problems, this application discloses a method for preparing a polyurethane masterbatch, comprising the following steps:

[0007] A mixture of aqueous graphene oxide solution and aqueous polyurethane emulsion was prepared.

[0008] Adding an aqueous solution of quaternary ammonium salt to the mixed solution demulsifies and precipitates the product.

[0009] The product was washed, filtered, and dried to obtain polyurethane masterbatch.

[0010] Optionally, the ratio of the solid content of the aqueous polyurethane emulsion, the mass of graphene in the graphene oxide aqueous solution, and the mass of quaternary ammonium salt in the quaternary ammonium salt aqueous solution is 100:(0.5-10):(1-5).

[0011] Optionally, the concentration range of the quaternary ammonium salt aqueous solution is 5–10 mg / mL;

[0012] The reaction temperature between the quaternary ammonium salt aqueous solution and the mixed solution is 45–65 degrees Celsius.

[0013] Optionally, the concentration of the water-soluble graphene oxide is 0.5% to 4%.

[0014] Optionally, the waterborne polyurethane emulsion includes anionic polyurethane and / or nonionic polyurethane;

[0015] The solid content of this waterborne polyurethane emulsion is 30-60%.

[0016] Optionally, the mixture may be stirred while adding the quaternary ammonium salt aqueous solution;

[0017] The stirring speed is 200-1000 rpm, and the stirring time is 5-30 minutes.

[0018] Optionally, the quaternary ammonium salt in the aqueous quaternary ammonium salt solution is one or more of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyldimethylbenzylammonium, and polydiallyldimethylammonium chloride.

[0019] Optionally, the product is washed, filtered, and dried to obtain a polyurethane masterbatch, comprising:

[0020] The product was washed, filtered, crushed and dried to obtain polyurethane masterbatch;

[0021] The filtered product is crushed using either a pulverizer or a crusher.

[0022] The drying temperature is 50–80 degrees Celsius;

[0023] The drying time is 12 to 24 hours.

[0024] In another aspect, this application also discloses a polyurethane masterbatch, which is prepared by the above-described preparation method.

[0025] In another aspect, this application also discloses the application of a polyurethane masterbatch, such as the polyurethane masterbatch obtained by the above preparation method, in the preparation of thermoplastic polyurethane / graphene composite materials using at least one of a two-roll mill, an extruder, and an injection molding machine.

[0026] By adopting the above technical solution, the method for preparing polyurethane masterbatch provided in this application has the following beneficial effects:

[0027] This application provides a method for preparing polyurethane masterbatch, which includes the following steps: first, a mixture of graphene oxide aqueous solution and aqueous polyurethane emulsion is prepared; then, a quaternary ammonium salt aqueous solution is added to the mixture while stirring, causing demulsification and precipitation of the product; the product is then washed, filtered, and dried to obtain polyurethane masterbatch. Since this application uses a quaternary ammonium salt aqueous solution to demulsify the aqueous polyurethane, it not only has lower requirements for the reaction environment, thus simplifying the reaction steps, but also the quaternary ammonium salt has the advantages of low cost and non-toxicity. Therefore, the preparation method provided by this application has the advantages of low cost, environmental friendliness, and simple process; furthermore, the polyurethane masterbatch prepared by this method has the advantages of excellent wear resistance, tensile strength, and other physical properties. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the preparation process of an optional polyurethane masterbatch according to this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] As used herein, "an embodiment" or "an embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0032] For the purposes of the detailed description below, it should be understood that the invention may take various alternative variations and sequences of steps unless expressly stated otherwise. Furthermore, except in any operational instance, or otherwise indicated, all figures representing the amounts of ingredients used, for example, in the specification and claims, should be understood to be modified in all cases by the term “about.” Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations varying with the desired performance to be obtained according to the invention. It is not at all an attempt to limit the application of the doctrine of equivalents to the scope of the claims; each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying ordinary rounding techniques.

[0033] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​listed in the specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in their respective test measurements.

[0034] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0035] Existing technologies mostly employ the following processes to modify graphene so that it can be better dispersed in waterborne polyurethane, such as grafting or coating modification of graphene, and dispersing it in organic solvents such as N,N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP). These processes are complex and involve toxic solvents, which is detrimental to energy conservation and environmental protection. Therefore, this application discloses a method for preparing a polyurethane masterbatch, which directly adds an aqueous solution of graphene oxide to a compatible waterborne polyurethane emulsion. This avoids toxic solvents and complex processes, while maximizing the dispersion of graphene oxide in the polymer matrix; and the resulting polyurethane masterbatch exhibits excellent wear resistance. In this method, a positively charged quaternary ammonium salt acts as a demulsifier, rapidly breaking the stability of the waterborne polyurethane, quickly demulsifying, and achieving uniform coating of graphene oxide by the polyurethane. Meanwhile, this type of quaternary ammonium salt has low cost, which is conducive to the efficient and low-cost production of industrial polyurethane / graphene oxide masterbatch.

[0036] See Figure 1 , Figure 1 This is a schematic diagram of an optional polyurethane masterbatch preparation process according to this application. The preparation method of the polyurethane masterbatch includes the following steps:

[0037] S101: Prepare a mixture of aqueous graphene oxide solution and aqueous polyurethane emulsion.

[0038] Optionally, the preparation process of the graphene oxide aqueous solution in step S101 is as follows: dissolve the graphene oxide solid powder in deionized water or distilled water.

[0039] In some feasible embodiments, the waterborne polyurethane emulsion is of the type of anionic polyurethane, nonionic polyurethane, or a mixture of both; the solid content of the waterborne polyurethane emulsion is 30-60%, thereby enabling this type of waterborne polyurethane to react with subsequent quaternary ammonium salts to achieve demulsification and generate a product in which polyurethane uniformly coats graphene oxide.

[0040] Optionally, anionic polyurethanes include carboxylic acid type and sulfonic acid type waterborne polyurethanes; nonionic polyurethanes include waterborne polyurethanes that do not contain ionic groups in their molecules or polyurethanes that contain hydroxymethyl groups.

[0041] S102: Add an aqueous solution of quaternary ammonium salt to the mixed solution to demulsify and precipitate the product.

[0042] In this embodiment, because the quaternary ammonium salt aqueous solution produces positively charged NH4... +It can disrupt the charge stability of anionic or nonionic polyurethane systems, thereby achieving demulsification and uniform coating of graphene oxide by polyurethane.

[0043] To ensure the precipitated product while avoiding waste of raw materials, in some feasible embodiments, the ratio of the solid content of the aqueous polyurethane emulsion, the mass of graphene in the graphene oxide aqueous solution, and the mass of quaternary ammonium salt in the quaternary ammonium salt aqueous solution is 100:(0.5-10):(1-5). For example, when the mass of the solid content of the aqueous polyurethane emulsion in the mixture is 100, the mass of graphene in the graphene oxide aqueous solution ranges from 0.5 to 10; the mass of quaternary ammonium salt in the quaternary ammonium salt aqueous solution ranges from 1 to 5. The units can be milligrams, grams, or kilograms, and can also be multiples of the above units, such as ten or twenty times, as needed, without limitation.

[0044] To improve the product precipitation efficiency, in some feasible embodiments, the concentration of the quaternary ammonium salt aqueous solution is in the range of 5–10 mg / mL; the reaction temperature of the quaternary ammonium salt aqueous solution with the mixed solution is 45–65 degrees Celsius.

[0045] To improve the application flexibility of the polyurethane masterbatch while ensuring its physicochemical properties, in some feasible embodiments, the concentration of the water-soluble graphene oxide is 0.5% to 4%.

[0046] In some feasible embodiments, the quaternary ammonium salt in the aqueous quaternary ammonium salt solution is one or more of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyldimethylbenzylammonium, and polydiallyldimethylammonium chloride.

[0047] In some feasible embodiments, the mixed solution is stirred while adding an aqueous solution of quaternary ammonium salt; the stirring speed is 200 to 1000 rpm and the stirring time is 5 to 30 minutes, so that the quaternary ammonium salt is more uniformly mixed in the mixed solution, thereby further improving the product precipitation efficiency and product yield.

[0048] S103: The product is washed, filtered and dried to obtain polyurethane masterbatch.

[0049] In some feasible embodiments, step S103 can be specifically represented as: washing, filtering, crushing and drying the product to obtain polyurethane masterbatch; crushing the filtered product using either a pulverizer or a crusher; the drying temperature is 50 to 80 degrees Celsius; the drying time is 12 to 24 hours. When the temperature is lower, such as 50 degrees Celsius, the required drying time is longer. Conversely, when the drying temperature is higher, the drying time can be reduced.

[0050] In another aspect, this application also discloses a polyurethane masterbatch, which is prepared by the above-described preparation method.

[0051] This application also discloses an application of a polyurethane masterbatch. For example, the polyurethane masterbatch obtained using the above preparation method is added to a device with a thermoplastic polyurethane material. This device physically mixes the polyurethane masterbatch and the thermoplastic polyurethane material, melts the base, and simultaneously achieves the thermal reduction of graphene oxide, thereby preparing a composite polymer material. Furthermore, it does not involve toxic reagents, the preparation process is simple and efficient, the cost is low, and it is easy to industrialize.

[0052] Optionally, the equipment includes one of an open mill, an extruder, and an injection molding machine.

[0053] To better illustrate the beneficial effects of this application, specific embodiments will be described below.

[0054] Example 1:

[0055] (1) 0.6g of graphene oxide was mixed with 2% graphene oxide aqueous solution and 50g of 60% nonionic waterborne polyurethane emulsion and stirred at 200r / min for 30min; 48ml of 10mg / ml quaternary ammonium salt aqueous solution was added dropwise to the above solution while stirring at 65℃, and the product precipitated.

[0056] (2) Wash and filter twice with distilled water, crush the above product with a pulverizer, and then place the product in a 60℃ oven for 24 hours to obtain a polyurethane masterbatch with a content of 2.0%.

[0057] (3) Add polyurethane masterbatch to thermoplastic polyurethane and injection mold at 180°C to form test strips with a graphene oxide addition of 0.1%.

[0058] It should be noted that the above-mentioned 2% graphene oxide aqueous solution can refer to an aqueous solution of 30 ml and a solute, i.e., the mass of graphene oxide, of 0.6 g; the above-mentioned 60% nonionic waterborne polyurethane emulsion can refer to a solid content (i.e., nonionic waterborne polyurethane) of 30 g and an emulsion mass of 50 g. The meanings of the parameters of the solution or emulsion in the following text are the same as those in this embodiment, and will not be repeated below.

[0059] Example 2:

[0060] (1) 0.6g of graphene oxide was mixed with 4% graphene oxide aqueous solution and 20g of 60% nonionic waterborne polyurethane emulsion and stirred at 500r / min for 15min. The above solution was stirred at 55℃ while 43ml of 10mg / ml quaternary ammonium salt aqueous solution was added dropwise, and the product precipitated.

[0061] (2) Wash and filter twice with distilled water, crush the above product with a pulverizer, and then place the product in an 80℃ oven for 12 hours to obtain a polyurethane masterbatch with a content of 5.0%.

[0062] (3) Add polyurethane masterbatch to thermoplastic polyurethane and refine at 180°C to obtain test strips with a graphene oxide addition of 0.2%.

[0063] Example 3:

[0064] (1) 1.2g of graphene oxide was mixed with 4% graphene oxide aqueous solution and 20g of 60% nonionic waterborne polyurethane emulsion and stirred at 500r / min for 15min. 120ml of 5mg / ml quaternary ammonium salt aqueous solution was added dropwise to the above solution while stirring at 45℃, and the product precipitated.

[0065] (2) Wash and filter twice with distilled water, crush the above product with a pulverizer, and then place the product in an 80℃ oven for 12 hours to obtain a polyurethane masterbatch with a content of 10.0%.

[0066] (3) Add polyurethane masterbatch to thermoplastic polyurethane and injection mold at 190°C to form test strips with a graphene oxide addition of 0.3%.

[0067] Example 4:

[0068] (1) 0.12g of graphene oxide was mixed with 80g of 30% anionic aqueous polyurethane emulsion to prepare a 0.5% graphene oxide aqueous solution and stirred at 1000r / min for 5min. The above solution was stirred at 65℃ while 24ml of 5mg / ml quaternary ammonium salt aqueous solution was added dropwise, and the product precipitated.

[0069] (2) Wash and filter twice with distilled water, crush the above product with a pulverizer, and then place the product in an 80℃ oven for 12 hours to obtain a polyurethane masterbatch with a content of 0.5%.

[0070] (3) Add polyurethane masterbatch to thermoplastic polyurethane and injection mold at 190°C to form test strips with a graphene oxide addition of 0.05%.

[0071] Provide test strips for Comparative Example 1. TPU slices are injection molded at 180°C to form blank control test strips.

[0072] The test strips for Comparative Example 2 are provided by mechanically blending 0.3% graphene powder with TPU chips. The graphene is adsorbed onto the surface of the TPU chips through electrostatic interaction, and then injection molded into test strips at 180°C.

[0073] The test specimens prepared in Examples 1-4 and Comparative Example 1 were tested for DIN abrasion resistance, tensile strength, and elongation at break using a DIN abrasion tester. The test methods were GB / T 9867-2008 Determination of Abrasion Resistance of Vulcanized Rubber or Thermoplastic Rubber (Rotating Roller Abrasion Tester Method) and GB / T 528-2009 Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber. The results are shown in Table 1 below. Compared with Comparative Example 1, in Example 3, when the amount of graphene oxide (GO) added was 0.3%, the DIN abrasion was the least, decreasing by about 40.10%, the tensile strength increased by 32.85%, and the elongation at break decreased slightly, by 13.80%. In Example 4, the elongation at break increased by 31.23%. Furthermore, when the amount of graphene (or graphene oxide) added is the same (Example 3 and Comparative Example 2), the composite polymer material prepared by the method of this application has significantly better DIN wear, tensile strength and elongation at break than the material prepared by electrostatic method in the prior art.

[0074] Table 1. Test results of the samples from Examples 1-4 and Comparative Examples 1-2

[0075] GO content (%) 0.1 0.2 0.3 0.05 0 0.3 <![CDATA[DIN Abrasion( mm 3 )]]> 26.64 22.92 21.37 32.43 36.20 32.77 Tensile strength (MPa) 13.90 14.53 16.62 13.06 12.51 13.49 Elongation at break (%) 1081 949 806 1227 935 620

[0076] It should be noted that the selection of materials and experimental parameters involved in the above embodiments are only for the purpose of obtaining better control experimental results and better demonstrating the beneficial effects of the polyurethane masterbatch preparation method provided by this application. They are only as a specific and feasible embodiment. The materials and parameters that can actually be implemented in this application are not limited to those in the embodiments, and can be referred to the specific scope of the implementation.

[0077] In summary, the preparation method of the polyurethane masterbatch provided in this application involves mixing and dispersing an aqueous graphene oxide solution and an aqueous polyurethane emulsion, then adding a quaternary ammonium salt aqueous solution dropwise to the mixed solution while stirring, thereby demulsifying and precipitating the product. The mass ratio of the polyurethane emulsion solid content, graphene oxide, and quaternary ammonium salt is 100:(0.5-10):(1-5). The product is then washed with distilled water, filtered, and dried to obtain the polyurethane masterbatch. By directly adding the aqueous graphene oxide solution to a compatible aqueous polyurethane emulsion, toxic solvents and complex processes are avoided, while maximizing the dispersion of graphene oxide in the masterbatch matrix. Furthermore, the use of an industrially available quaternary ammonium salt as a demulsifier enables efficient production of the polyurethane masterbatch. This polyurethane masterbatch can be directly physically mixed with thermoplastic polyurethane polymer resin and then melt-extruded, simultaneously achieving the thermal reduction of graphene oxide, thereby preparing a composite material with high wear resistance and other properties. In addition, the above composite material possesses a unique graphene black color, and this wear-resistant reinforced polyurethane masterbatch can also be used as a graphene black masterbatch. In summary, this invention does not involve toxic reagents, has a simple and efficient preparation process, low cost, and is easy to industrialize.

[0078] The above description is only an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a polyurethane masterbatch, characterized in that, Includes the following steps: A mixed solution of an aqueous graphene oxide solution and an aqueous polyurethane emulsion is prepared; wherein the aqueous polyurethane emulsion includes a nonionic polyurethane. Add an aqueous solution of a quaternary ammonium salt to the mixed solution to demulsify and precipitate the product; The product is washed, filtered, and dried to obtain a polyurethane masterbatch; while adding the quaternary ammonium salt aqueous solution to the mixed solution, the mixed solution is stirred; the stirring time is 5 to 30 minutes; the reaction temperature of the quaternary ammonium salt aqueous solution with the mixed solution is 45 to 65 degrees Celsius. The ratio of the solid content of the aqueous polyurethane emulsion, the mass of graphene oxide in the aqueous graphene oxide solution, and the mass of quaternary ammonium salt in the aqueous quaternary ammonium salt solution is 100:(0.5-10):(1-5).

2. The preparation method according to claim 1, characterized in that, The concentration range of the quaternary ammonium salt aqueous solution is 5–10 mg / mL.

3. The preparation method according to claim 1 or 2, characterized in that, The concentration of the water-soluble graphene oxide is 0.5% to 4%.

4. The preparation method according to claim 1, characterized in that, The solid content of the waterborne polyurethane emulsion is 30-60%.

5. The preparation method according to claim 1, characterized in that, The stirring speed is 200-1000 rpm.

6. The preparation method according to claim 1, characterized in that, The quaternary ammonium salt in the aqueous solution is one or more of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyldimethylbenzylammonium, and polydiallyldimethylammonium chloride.

7. The preparation method according to claim 1, characterized in that, The product is washed, filtered, and dried to obtain a polyurethane masterbatch, comprising: The product is washed, filtered, crushed and dried to obtain polyurethane masterbatch; The filtered product is crushed using either a pulverizer or a crusher. The drying temperature is 50–80 degrees Celsius; The drying time is 12 to 24 hours.

8. A polyurethane masterbatch, characterized in that, The polyurethane masterbatch is prepared by the preparation method according to any one of claims 1 to 7.

9. An application of a polyurethane masterbatch, characterized in that, The application of the polyurethane masterbatch obtained by the preparation method according to any one of claims 1 to 7 in the preparation of thermoplastic polyurethane / graphene composite materials using at least one of the following equipment: open mill, extruder, and injection molding machine.

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