High-content graphene pre-dispersion for epoxy resin and preparation method of high-content graphene pre-dispersion

Abstract

The invention discloses a high-content graphene pre-dispersion for epoxy resin and a preparation method of the high-content graphene pre-dispersion, and relates to the technical field of carbon material dispers.The preparation method comprises the following operation steps that an epoxy diluent, a dispersing agent and a stabilizer are evenly mixed for 10-30 min at the rotating speed of 200-1000 r / min, and a dispersion carrier is obtained; the preparation method comprises the following steps: uniformly mixing graphene with a dispersion carrier, and grinding by a three-roller machine to obtain a high-content graphene pre-dispersion; the high-content graphene pre-dispersion is applied to epoxy resin and a binder.

Description

Technical Field

[0001] The invention relates to the technical field of carbon material dispersions, in particular to a high-content graphene predispersion for epoxy resin and a preparation method thereof. Background Art

[0002] Epoxy resin is a high molecular polymer containing two or more epoxy groups in its molecular structure and is one of the four major synthetic resins. Epoxy resin has the advantages of high mechanical properties, strong adhesion, good thermal stability and small shrinkage. It is widely used as coatings and adhesives in electronics, electrical appliances and other fields.

[0003] However, after curing, epoxy resin has a high cross-linking density, large internal stress, poor impact toughness, poor weather resistance, and easy pulverization. In view of the shortcomings of epoxy resin, domestic and foreign scholars have conducted a lot of research on epoxy resin modification. At present, the modification methods of epoxy resin are mainly divided into chemical modification and physical modification.

[0004] Chemical modification mainly involves the introduction of functional groups during the synthesis of epoxy resins to synthesize epoxy resins with new structures; physical modification involves the introduction of other modifiers and fillers into blends with basic epoxy resins to improve the performance of epoxy resins; nanocarbon materials can be used as fillers for epoxy resins, which have the advantages of nanosize effect, small dosage, and obvious effect; commonly used carbon materials usually include carbon black, carbon fiber, carbon nanotubes and graphene. The addition of carbon materials can significantly improve the conductive and mechanical properties of composite epoxy resins.

[0005] Among them, graphene has a two-dimensional network structure, and the carbon atoms in graphene are stably arranged in a hexagonal shape. It has the advantages of high conductivity, high thermal conductivity, high strength, ultra-lightness, high flexibility, high chemical stability and high specific surface area. It has important potential application prospects in many fields. Graphene added to epoxy resin can further enhance the mechanical properties of epoxy resin, improve its shortcomings of poor toughness, high brittleness and easy pulverization; at the same time, it can also improve the conductivity of epoxy resin and enhance its antistatic and conductive capabilities.

[0006] However, graphene powder has problems such as low density, difficulty in feeding and dispersion; it cannot be directly mixed with epoxy resin; and at the same time, due to the van der Waals force between graphene sheets, it is difficult to achieve the expected effect when mixed; CN113773727A discloses a method for preparing a graphene oxide modified epoxy resin coating, which is graphene oxide prepared by a chemical method, so that the graphene is more easily dispersed in the epoxy resin after being functionalized; CN117700939A discloses a graphene modified epoxy resin and its preparation method and application, which require additional heating and reaction in a reactor during the preparation process to achieve qualified results.

[0007] In summary, the present invention discloses a high-content graphene dispersion for epoxy resin and a preparation method thereof. The dispersion can be directly added to the epoxy resin and can be used after simple mechanical stirring, dilution and dispersion. Summary of the invention

[0008] The object of the present invention is to provide a high-content graphene predispersion for epoxy resin and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0010] A method for preparing a high-content graphene predispersion for epoxy resin comprises the following steps: adding graphene into a dispersion carrier for multiple times and mixing evenly, and then grinding with a three-roll mill to obtain a high-content graphene predispersion.

[0011] More optimally, the dispersion carrier includes a dispersant, a stabilizer, and an epoxy diluent; the raw materials of the high-content graphene pre-dispersion include the following components: 5 to 40 parts of graphene, 20 to 100 parts of epoxy diluent, 0.5 to 5 parts of dispersant, and 0.1 to 5 parts of stabilizer in parts by mass.

[0012] In the scheme, the epoxy diluent, dispersant and stabilizer are uniformly mixed at a rotation speed of 200 to 1000 r / min for 10 to 30 minutes to obtain a dispersion carrier.

[0013] More optimally, the roller spacing of the three-roller mill is 5 to 100 μm; the roller speed is 100 to 500 r / min, and the grinding is 5 to 25 times.

[0014] More optimally, the dispersant includes one or more of hexadecyltrimethylammonium bromide, polyvinyl pyrrolidone, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium lignin sulfonate, polyvinyl alcohol, polyethylene oxide, polyacrylic acid, polymethacrylic acid or polyacrylamide; the stabilizer includes one or more of butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt, 1-hexyl-3-methyl hexafluorophosphate, 1-butyl-3-methylimidazole hexafluoroborate, N,N,N-tributyl-N-octylamine methanesulfonate ammonium, and ethoxylated isotridecanol phosphate.

[0015] More optimally, the dispersant is polyethylene glycol, and the stabilizer is 1-butyl-3-methylimidazole hexafluoroborate; the mass ratio of the dispersant to the stabilizer is 1:1.

[0016] Preferably, the epoxy diluent includes one or more of alkyl glycidyl ether, fatty acid glycidyl ester, propylene oxide butyl ether, dipropylene oxide ethyl ether, ethylene glycol monoethyl ether, phenyl glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

[0017] Preferably, the particle size of the graphene is less than 100 μm; and the number of graphene layers is 2 to 15.

[0018] Preferably, the graphene is one or a mixture of graphene prepared by physical method and chemical method; and the particle size of the graphene is less than 20 μm.

[0019] A high-content graphene predispersion prepared by a method for preparing a high-content graphene predispersion for epoxy resin is characterized in that the high-content graphene predispersion is applied to modified epoxy resin coatings or adhesives.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) In the present invention, graphene is added to the dispersion carrier in multiple times, and the van der Waals force between graphene is reduced by adding a dispersant and a stabilizer, thereby improving its compatibility with high molecular polymers. The graphene powder is fully wetted by adding multiple times, and the dispersion of graphene is ensured by mechanical stirring and three-roll grinding. The reaction process is mild and easy to control, and the degree of automation is high.

[0021] (2) The high-content graphene dispersion prepared by the present invention can be diluted and redispersed, and applied to the modification of functional epoxy resin, thereby improving the conductivity, mechanical toughness and weather resistance of the epoxy resin, which is conducive to the further application of epoxy resin in high-end fields and increases the added value of epoxy resin.

[0022] (3) The method of the present invention has a simple preparation process, easy-to-control reaction conditions, safe and controllable product composition, is conducive to large-scale production, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 An epoxy resin film with 5% graphene content;

[0024] Figure 2 An epoxy resin film with 0.1% graphene content;

[0025] Figure 3 An epoxy resin film with 0.5% graphene content;

[0026] Figure 4 A partial enlarged view of an epoxy resin film with 0.5% graphene content. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the following examples, the parts are by mass. In this example, it should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions. Examples include: the specifications of the physical method graphene powder are 13-18 μm in particle size and ≥30 m in specific surface area. 2 / g, purchased from Qingdao Yanhai Carbon Materials Co., Ltd.; the specifications of chemically reduced graphene oxide powder are 35-50 μm in particle size and ≥400 m in specific surface area. 2 / g, purchased from Changzhou Sixth Element Material Technology Co., Ltd.

[0029] Example 1: A method for preparing a high-content graphene predispersion for epoxy resin;

[0030] Step 1: 100 parts of alkyl glycidyl ether, 2 parts of polyvinyl alcohol and 2 parts of 1-butyl-3-methylimidazolium hexafluoroborate were mixed at a speed of 600 r / min for 20 minutes to obtain a dispersion carrier;

[0031] Step 2: 18 parts of graphene were added to the dispersion carrier in 5 times, mixed at a speed of 800 r / min for 30 minutes, and then premixed by a three-roller machine. After premixing, the roller distance was adjusted to 10 μm, and the three-roller machine was rolled 20 times at a speed of 120 r / min to obtain a high-content graphene dispersion;

[0032] The graphene is a physical graphene powder with an average number of 6 layers and an average particle size of 20 μm.

[0033] Example 2: A method for preparing a high-content graphene predispersion for epoxy resin;

[0034] Step 1: 90 parts of alkyl glycidyl ether, 3 parts of hexadecyl trimethyl ammonium bromide and 2 parts of butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt were mixed at a speed of 500 r / min for 30 minutes to obtain a dispersion carrier;

[0035] Step 2: Add 20 parts of graphene to the dispersion carrier in 5 times, mix at a speed of 1000 r / min for 30 minutes, and then premix on a three-roller machine. After premixing, adjust the roller distance to 10 μm, and roll 20 times at a speed of 120 r / min to obtain a high-content graphene dispersion;

[0036] The graphene is a physical graphene powder with an average number of layers of 5 and an average particle size of 10 μm.

[0037] Example 3: A method for preparing a high-content graphene predispersion for epoxy resin;

[0038] Step 1: 80 parts of 1,4-butanediol diglycidyl ether, 4 parts of sodium lignin sulfonate and 3 parts of N,N,N-tributyl-N-octylamine methanesulfonate ammonium were mixed at a speed of 500 r / min for 30 minutes to obtain a dispersion carrier;

[0039] Step 2: 20 parts of graphene were added to the dispersion carrier in 6 times, mixed at a speed of 1500 r / min for 30 minutes, and then premixed by a three-roller machine. After premixing, the roller distance was adjusted to 5 μm, and the three-roller machine was rolled 20 times at a speed of 160 r / min to obtain a high-content graphene dispersion;

[0040] Among them, the chemically reduced graphene oxide powder has an average number of graphene layers of 4 and a particle size of 15 μm.

[0041] Example 4: A method for preparing a high-content graphene predispersion for epoxy resin;

[0042] Step 1: 100 parts of fatty acid glycidyl ester, 3 parts of sodium lauryl sulfate and 3 parts of ethoxylated isotridecanol phosphate were mixed at a speed of 800 r / min for 30 minutes to obtain a dispersion carrier;

[0043] Step 2: 10 parts of graphene were added to the dispersion carrier in 5 times, mixed at a speed of 1200 r / min for 30 minutes, and then premixed by a three-roller machine. After premixing, the roller distance was adjusted to 8 μm, and the three-roller machine was rolled 15 times at a speed of 160 r / min to obtain a high-content graphene dispersion;

[0044] The graphene is a graphene powder prepared by physical method with an average number of layers of 5 and a particle size of 15 μm.

[0045] Example 5: A method for preparing a high-content graphene predispersion for epoxy resin;

[0046] Step 1: 50 parts of phenyl glycidyl ether, 2 parts of polyacrylic acid and 1.5 parts of butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt were mixed at a speed of 1000 r / min for 40 minutes to obtain a dispersion carrier;

[0047] Step 2: 30 parts of graphene were added to the dispersion carrier in 8 times, mixed at a speed of 1500 r / min for 30 minutes, and then premixed by a three-roller machine. After premixing, the roller distance was adjusted to 5 μm, and the three-roller machine was rolled 15 times at a speed of 180 r / min to obtain a high-content graphene dispersion;

[0048] The graphene is a graphene powder prepared by a physical method with an average number of layers of 18 and a particle size of 30 μm.

[0049] Comparative Example 1: No three-roller mixing was performed;

[0050] Step 1: 100 parts of alkyl glycidyl ether, 2 parts of polyvinyl alcohol and 2 parts of 1-butyl-3-methylimidazolium hexafluoroborate were mixed at a speed of 600 r / min for 20 minutes to obtain a dispersion carrier;

[0051] Step 2: adding 18 parts of graphene into the dispersion carrier in 5 times, mixing at a speed of 800 r / min for 30 minutes to obtain a high-content graphene dispersion;

[0052] The graphene is a graphene powder prepared by physical method with an average number of layers of 6 and a particle size of 20 μm.

[0053] Comparative Example 2: No stabilizer was added;

[0054] Step 1: Dispersing 90 parts of alkyl glycidyl ether and 3 parts of hexadecyl trimethyl ammonium bromide at a speed of 500 r / min for 30 minutes to obtain a dispersion carrier;

[0055] Step 2: 20 parts of graphene were added to the dispersion carrier in 5 times, mixed at a speed of 1000 r / min for 30 minutes, and then premixed by a three-roller machine. After premixing, the roller distance was adjusted to 10 μm, and the three-roller machine was rolled 20 times at a speed of 120 r / min to obtain a high-content graphene dispersion;

[0056] The graphene is a physical graphene powder with an average number of layers of 5 and an average particle size of 10 μm.

[0057] Comparative Example 3: No dispersant and stabilizer were added;

[0058] 22 parts of graphene were added to 87 parts of 1,4-butanediol diglycidyl ether in 6 times, mixed at a speed of 1500 r / min for 30 minutes, and then premixed by a three-roller machine. After premixing, the roller distance was adjusted to 5 μm, and the three-roller machine was rolled 20 times at a speed of 160 r / min to obtain a high-content graphene dispersion;

[0059] The graphene is chemically reduced graphene oxide powder with an average number of layers of 4 and an average particle size of 15 μm.

[0060] Detection test: (1) The average particle size of graphene in Examples 1 to 5 and Examples 1 to 3 when three-roll milling is not performed, and the content and average particle size of graphene in the high-content graphene dispersion in Examples 1 to 5 and Comparative Examples 1 to 3 are recorded as shown in Table 1;

[0061] (2) The high-content graphene dispersion prepared in Examples 1 to 5 and Comparative Examples 1 to 3 was used to modify the epoxy resin coating; the process comprises the following steps: 20 g of bisphenol A epoxy resin was taken and preheated at 60° C. A certain mass of Examples 1 to 5 and Comparative Examples 1 to 3 (high-content graphene dispersion) was added to the preheated bisphenol A epoxy resin, and stirred at a speed of 1200 r / min for 30 minutes; then, 5 g of curing agent (diethylenetriamine) was added, and after mechanical stirring, the mixture was evenly coated on a PET film by scrapering. After curing and molding at 80° C., a modified epoxy resin coating was obtained, and the volume resistivity was tested, as shown in Table 2.

[0062]

[0063] Table 1

[0064]

[0065]

[0066] Table 2

[0067] Conclusion: It can be seen from the data in Table 1 and Table 2 that the high-content graphene dispersions prepared in Examples 1 to 5 can be well dispersed in epoxy resin, and Example 1 is the optimal solution; in Comparative Example 1, no three-roller mixing was performed; as a result, in the high-content graphene dispersion, the particle size of the graphene did not change, and its volume resistivity increased, which shows that the graphene ground by three rollers can improve the conductive properties of the epoxy resin; in Comparative Example 2, no stabilizer was added; it was used to prepare an epoxy resin diaphragm, and its conductivity was significantly lower than that of the embodiment with the stabilizer added, indicating that the addition of the stabilizer will affect the conductivity of the epoxy resin diaphragm; in Comparative Example 3, no dispersant and stabilizer were added; therefore, the conductivity was reduced, but compared with Comparative Example 1, its conductivity was better.

[0068] In summary, adding graphene prepared by different methods into the dispersion carrier multiple times can ensure that the graphene is fully infiltrated in the epoxy resin; adding stabilizers and dispersants can improve the conductivity of the epoxy resin diaphragm; after grinding and mixing with a three-roll mill, the particle size of graphene in the high-content graphene dispersion becomes smaller, and the conductivity of the epoxy resin diaphragm becomes stronger.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a high-content graphene predispersion for epoxy resin, characterized in that: The following steps are involved: The graphene is added into the dispersion carrier several times and mixed evenly, and then ground by a three-roll mill to obtain a high-content graphene pre-dispersion.

2. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 1, characterized in that: The dispersion carrier includes a dispersant, a stabilizer, and an epoxy diluent; the raw materials of the high-content graphene pre-dispersion include the following components: 5 to 40 parts of graphene, 20 to 100 parts of epoxy diluent, 0.5 to 5 parts of dispersant, and 0.1 to 5 parts of stabilizer in parts by mass.

3. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 1, characterized in that: The roller spacing of the three-roller mill is 5 to 100 μm; the roller speed is 100 to 500 r / min, and the grinding is performed 5 to 25 times.

4. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 2, characterized in that: The dispersant includes one or more of hexadecyltrimethylammonium bromide, polyvinyl pyrrolidone, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium lignin sulfonate, polyvinyl alcohol, polyethylene oxide, polyacrylic acid, polymethacrylic acid or polyacrylamide; the stabilizer includes one or more of butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt, 1-hexyl-3-methyl hexafluorophosphate, 1-butyl-3-methylimidazole hexafluoroborate, N,N,N-tributyl-N-octylamine methanesulfonate ammonium, and ethoxylated isotridecanol phosphate.

5. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 4, characterized in that: The dispersant is polyethylene glycol; the stabilizer is 1-butyl-3-methylimidazole hexafluoroborate; and the mass ratio of the dispersant to the stabilizer is 1:

1.

6. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 2, characterized in that: The epoxy diluent includes one or more of alkyl glycidyl ether, fatty acid glycidyl ester, propylene oxide butyl ether, dipropylene oxide ethyl ether, ethylene glycol monoethyl ether, phenyl glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

7. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 1, characterized in that: The particle size of the graphene is less than 100 μm; the number of layers of the graphene is 2 to 15.

8. The method for preparing a high-content graphene predispersion for epoxy resin according to claim 7, characterized in that: The graphene is one or a mixture of graphene prepared by physical method and chemical method; the particle size of the graphene is less than 20 μm.

9. The high-content graphene predispersion prepared by the method for preparing a high-content graphene predispersion for epoxy resin according to any one of claims 1 to 8, characterized in that: The high-content graphene predispersion is applied to modified epoxy resin coating or adhesive.

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