Modified montmorillonite, epoxy resin cured product, waterborne epoxy anticorrosive coating and preparation method of waterborne epoxy anticorrosive coating

Abstract

The invention relates to modified montmorillonite, an epoxy resin condensate, a water-based epoxy anticorrosive coating and a preparation method of the water-based epoxy anticorrosive coating. The modified montmorillonite is prepared from Tween 60 and montmorillonite in a mass ratio of 1: (1-5). The modified inorganic montmorillonite / epoxy resin cured material is prepared from the modified montmorillonite, epoxy resin, an epoxy curing agent and other raw materials, and the epoxy resin material has good flame retardance and heat resistance. The modified montmorillonite / water-borne epoxy resin anti-corrosion coating is prepared from the modified montmorillonite, epoxy resin, filler, auxiliaries, an epoxy curing agent and other raw materials, the anti-corrosion performance of the coating is effectively improved, compared with pure epoxy resin, the glass transition temperature of the modified montmorillonite / epoxy anti-corrosion coating is obviously increased, and the anti-corrosion performance of the coating is improved. The heat resistance is better.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic fillers, composite materials and coatings, and specifically relates to a modified montmorillonite, epoxy resin cured product, water-based epoxy anti-corrosion coating and a preparation method thereof. Background Art

[0002] As an important basic material of thermosetting plastics, epoxy resin has high cross-linking density, low curing shrinkage, excellent thermal properties, physical and mechanical properties, corrosion resistance, etc. It is widely used in the fields of electronics, aerospace, etc. However, the defects of epoxy resin cured products such as easy combustion limit the application of epoxy resin. Therefore, it is necessary to improve the flame retardant properties of epoxy resin.

[0003] Epoxy anti-corrosion coatings not only have the advantages of strong corrosion resistance, good electrical insulation, good mechanical properties, but also have excellent process characteristics such as room temperature operation and simple construction. They are widely used in anti-corrosion fields such as petroleum, chemical industry, and marine engineering. Compared with solvent-based epoxy anti-corrosion coatings, water-based anti-corrosion coatings have low VOC content and no adverse effects on the environment and health, which meets the requirements of the current green and low-carbon development of the coatings industry. However, when it is used in harsh corrosive environments to protect the substrate, its anti-corrosion performance is very high. In recent years, graphene oxide has been mostly added to epoxy anti-corrosion coatings to improve their anti-corrosion performance. However, the preparation process of graphene oxide is complicated and expensive, which limits its use. Summary of the invention

[0004] Based on this, the present invention provides a modified montmorillonite, which can not only improve the heat resistance and flame retardancy of epoxy resin, but also improve the anti-corrosion performance of water-based epoxy anti-corrosion coating.

[0005] Specifically, the present invention includes the following technical solutions.

[0006] In a first aspect, the present invention provides a modified montmorillonite prepared from Tween 60 and montmorillonite; the mass ratio of Tween 60 to montmorillonite is 1:1-5.

[0007] In some of the embodiments, the mass ratio of Tween 60 to montmorillonite is 1:1.5-3.5.

[0008] In some embodiments, the mass ratio of Tween 60 to montmorillonite is 1:1.5-2.5.

[0009] In some of the embodiments, the mass ratio of Tween 60 to montmorillonite is 1:1.8-2.2.

[0010] In a second aspect, the present invention provides a method for preparing the modified montmorillonite, comprising the following steps:

[0011] The Tween 60 is added into water, stirred and dissolved, and then montmorillonite is added and dispersed at high speed for 20 minutes to 60 minutes to obtain the modified montmorillonite.

[0012] In some embodiments, the mass ratio of Tween 60 to water is 1:8-12.

[0013] In some embodiments, the rotation speed of the high-speed dispersion is 2500 rpm-3500 rpm, preferably 2800 rpm-3200 rpm.

[0014] In a third aspect, the present invention provides the use of the modified montmorillonite as a flame retardant in the preparation of heat-resistant and flame-retardant epoxy resin.

[0015] In a fourth aspect, the present invention provides the use of the modified montmorillonite as a preservative in the preparation of a waterborne epoxy anti-corrosion coating.

[0016] In a fifth aspect, the present invention provides a heat-resistant and flame-retardant modified montmorillonite / epoxy resin cured product, which is prepared from raw materials including the following components in parts by weight:

[0017]

[0018] In some of the embodiments, the heat-resistant and flame-retardant modified montmorillonite / epoxy resin cured product is prepared from raw materials including the following components, in parts by weight:

[0019]

[0020] In some of the embodiments, the weight proportion of the modified montmorillonite in the solidified material is 1-12 parts, which may be 1-10 parts, 3-12 parts, 3-10 parts, 6-9 parts, 7-8 parts, 1-6 parts, more preferably 2-5 parts, more preferably 3.5-4.5 parts, and most preferably 4 parts.

[0021] In some embodiments, the weight of the modified montmorillonite in the solidified material is 3-12 parts by weight, preferably 3.6-11.3 parts by weight, more preferably 3.6-9.4 parts by weight, more preferably 6.5-8.4 parts by weight, and more preferably 7-7.8 parts by weight.

[0022] In some of the embodiments, the weight proportion of the modified montmorillonite may be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts.

[0023] In some embodiments, the modified montmorillonite is added to the cured product in an amount of 1-12 wt % of the epoxy resin, preferably 1-10 wt %, 1-6 wt %, more preferably 2-5 wt %, and more preferably 3.5-4.5 wt %.

[0024] In some embodiments, the epoxy resin is selected from one or more of bisphenol A epoxy resin and novolac epoxy resin, more preferably epoxy resin E51 and / or epoxy resin E54.

[0025] In some embodiments, the curing agent is selected from at least one of 4,4'-diaminodiphenylmethane, phenolic resin, diethylenetriamine and polyamide, preferably diethylenetriamine and / or polyamide YK651.

[0026] In some of the embodiments, the curing agent is a combination of diethylenetriamine and polyamide YK651 in a mass ratio of 1:0.5-2.

[0027] In a sixth aspect, the present invention provides a method for preparing the heat-resistant and flame-retardant modified montmorillonite / epoxy resin cured product, comprising the following steps:

[0028] The epoxy resin is dissolved in ethanol, and then the modified montmorillonite is added, and the mixture is dispersed at high speed at 55°C-65°C for 20min-40min to remove the solvent and bubbles; then the curing agent is added, stirred evenly, and then allowed to stand for curing to obtain the modified montmorillonite / epoxy resin cured product.

[0029] In some embodiments, the removal of solvent and bubbles is performed in a vacuum drying oven at 55°C-65°C.

[0030] In some embodiments, the dispersion speed is 1200 rpm-1800 rpm.

[0031] In a seventh aspect, the present invention provides a modified montmorillonite / waterborne epoxy anti-corrosion coating, which is prepared from raw materials including the following components in parts by weight:

[0032]

[0033]

[0034] In some of the embodiments, the modified montmorillonite / waterborne epoxy anticorrosion coating is prepared from raw materials including the following components, by weight:

[0035]

[0036] In some of the embodiments, the modified montmorillonite is added to the coating in an amount of 3-12 parts by weight, preferably 3.6-11.3 parts by weight, more preferably 3.6-9.4 parts by weight, more preferably 6.5-8.4 parts by weight, and more preferably 7-7.8 parts by weight.

[0037] In some embodiments, the modified montmorillonite is added in an amount of 1-6wt% of the weight of the cured layer, more preferably 2-5wt%, more preferably 3.5-4.5wt%, more preferably 3.8-4.2wt%, and most preferably 4%. The weight of the cured layer refers to the weight of the modified montmorillonite / waterborne epoxy anticorrosion coating after curing and drying, that is, the total weight of other preparation raw materials excluding water and ethanol.

[0038] In some embodiments, the epoxy resin is epoxy resin E51 or epoxy resin E54, more preferably epoxy resin E51.

[0039] In some of the embodiments, the curing agent is selected from diethylenetriamine and / or polyamide, preferably a combination of diethylenetriamine and polyamide YK651.

[0040] In some of the embodiments, the curing agent is a combination of diethylenetriamine and polyamide YK651 in a mass ratio of 1:0.5-2.

[0041] In some of the embodiments, the filler is selected from any two or a mixture of two or more of calcium carbonate, silicon powder, silicon dioxide, talc, titanium dioxide, zinc oxide, zinc phosphate, red iron oxide and mica powder.

[0042] In some embodiments, the filler is a combination of calcium carbonate, silica powder, mica, titanium dioxide, talc and zinc oxide, and the mass ratio of calcium carbonate, silica powder, mica, titanium dioxide, talc and zinc oxide is 2-4:2-4:1:2-4:0.8-1.2:0.8-1.2.

[0043] In some embodiments, the auxiliary agent is selected from at least one of a leveling agent, a wetting agent, a thickener and a defoamer. Among them, the wetting agent can be one of TEGO450, BYK346 and K-LS315 or a mixture of more than one. The thickener can be one of hydroxyethyl cellulose, hydroxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose and sodium carboxymethyl cellulose or a mixture of more than one. The defoamer is a mineral oil defoamer, a polysiloxane defoamer and a mixture of one or more of an amine, imine, and amide defoamer, more preferably one of BYK-024, BEK-760, BKY-066 or a mixture of more than one. The leveling agent is PW336.

[0044] In some of the embodiments, the auxiliary agent is a combination of leveling agent PW336, wetting agent BYK346, hydroxymethyl cellulose and defoaming agent BEK-760, and the mass ratio of the leveling agent PW336, wetting agent BYK346, hydroxymethyl cellulose and defoaming agent BEK-760 is 1:1-3:0.4-0.8:2-4.

[0045] In an eighth aspect, the present invention provides a method for preparing the modified montmorillonite / waterborne epoxy anti-corrosion coating, comprising the following steps:

[0046] The epoxy resin is dissolved in ethanol, and then water and the modified montmorillonite are added, and the epoxy resin is dispersed at a high speed for 50 minutes to 80 minutes to fully emulsify the epoxy resin. The filler and the auxiliary agent are added to the obtained epoxy resin emulsion, and the dispersion is uniform. Then, the curing agent is added and stirred uniformly to obtain the modified montmorillonite / waterborne epoxy anti-corrosion coating.

[0047] The present invention has the following beneficial effects:

[0048] The invention uses Tween 60 as a modifier to modify inorganic montmorillonite, and prepares a novel modified montmorillonite, which can not only improve the flame retardant and heat resistance of epoxy resin, but also improve the anticorrosion and heat resistance of waterborne epoxy anticorrosion coating.

[0049] The invention uses Tween 60 modified montmorillonite, epoxy resin and epoxy curing agent as raw materials to prepare modified inorganic montmorillonite / epoxy resin cured product. The epoxy resin material has good flame retardant and heat resistance, and improves the application performance of epoxy resin in the field of electronic plastic packaging materials.

[0050] The present invention uses raw materials such as montmorillonite modified by Tween 60, epoxy resin, filler, auxiliary agent and epoxy curing agent to prepare a modified montmorillonite / waterborne epoxy resin anti-corrosion coating, and the anti-corrosion performance of the coating is effectively improved. After the epoxy anti-corrosion coating is water-resistant for 168 hours, acid- and alkali-resistant for 48 hours and salt water-resistant for 168 hours, the surface of the coating has no peeling, no shedding, no blistering and no rust spots; and compared with pure epoxy resin, the glass transition temperature of the modified montmorillonite / epoxy anti-corrosion coating is significantly improved, and the heat resistance is better.

[0051] The addition amount of the modified montmorillonite is further optimized. When the addition amount is 4wt%, the anti-corrosion performance of the obtained water-based epoxy resin anti-corrosion coating is optimal; and at this time, the pencil hardness and impact resistance of the anti-corrosion epoxy coating are significantly better than those of pure epoxy coating, that is, a specific amount of the modified montmorillonite of the present invention can improve the anti-corrosion performance of the water-based epoxy anti-corrosion coating while improving its coating mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 SEM photos of montmorillonite / epoxy resin cured product (a) and modified montmorillonite / epoxy resin cured product (b).

[0053] Figure 2 is the glass transition temperature of the modified montmorillonite / epoxy resin cured product, where (a) is the DSC graph and (b) is the bar graph.

[0054] Figure 3 is the glass transition temperature (Tg) of modified montmorillonite / waterborne epoxy anti-corrosion coating. DETAILED DESCRIPTION

[0055] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0056] The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or conditions recommended by the manufacturers. The various commonly used chemical reagents used in the examples are all commercially available products.

[0057] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0058] In addition, as used in the present invention, the term "or" is an inclusive "or" symbol and is equivalent to the term "and / or", unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on other factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meanings of "a", "an", and "the" include plural referents. The meaning of "in..." includes "in..." and "on...".

[0059] The present invention is further described in detail below with reference to specific embodiments.

[0060] In the following examples, room temperature refers to an indoor temperature of 20-35°C.

[0061] The main raw materials used in the following examples and comparative examples are as follows:

[0062] Epoxy resin (E51): Epoxy value: 0.51 mol / 100g, Baling Petrochemical;

[0063] Diethylenetriamine: Guangzhou Yihuisheng Chemical Co., Ltd. or Nanjing Daze Trading Co., Ltd.;

[0064] Ethanol: AR, Sinopharm Chemical Reagent Sales Co., Ltd. or Shanghai Lizhi Chemical Co., Ltd.;

[0065] Inorganic montmorillonite: industrial grade, Zhejiang Fenghong New Materials Co., Ltd.

[0066] Polyamide curing agent YK651: industrial grade, Guangzhou Yike New Material Technology Co., Ltd.;

[0067] Polyoxyethylene sorbitan monostearate (Tween-60): industrial grade, Hai'an Petrochemical Plant, Jiangsu Province;

[0068] Filler: zinc phosphate, red iron oxide, silica powder, mica powder, etc.; Additives: leveling agent, defoaming agent, wetting agent, etc.

[0069] The main instruments and equipment used in the following examples and comparative examples are as follows:

[0070] Electric mixer: D2004W electric mixer, Shanghai Yuezhong Instrument Equipment Co., Ltd.;

[0071] High-speed disperser: SA30 high-speed disperser, Taicang Xide Machinery Technology Co., Ltd.;

[0072] Electronic balance: Model JJ1000, Guangzhou Dianrui Huabo Experimental Instrument Co., Ltd.;

[0073] Ultrasonic disperser: Scientz-750F, Ningbo Xinzhi Biotechnology Co., Ltd.;

[0074] Analytical balance: ME104TE, Mettler Toledo (Shanghai) Co., Ltd.;

[0075] Vacuum drying oven: DZF6021, Shanghai Yiheng Scientific Instrument Co., Ltd.;

[0076] Differential scanning calorimeter: Perkin-Elmer DSC-2C, PE Company, USA;

[0077] Thermogravimetric analyzer: TG 209F3, NETZSCH, Germany;

[0078] Scanning electron microscope (SEM): 400FEG, Quanta, the Netherlands;

[0079] Limiting oxygen index tester: Dynisco LOI, Dynisco Company, USA.

[0080] The following are specific embodiments.

[0081] Example 1 Preparation of modified montmorillonite

[0082] (1) Add 5 g of Tween 60 (TW-60) to 50 g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10 g of inorganic montmorillonite and disperse it with a SA30 high-speed disperser at 3000 rpm for 30 minutes until it becomes a uniform colloid. Modified montmorillonite (TW-MMT-50) can be obtained.

[0083] (2) Add 2 g of Tween 60 (TW-60) to 50 g of water and fully dissolve it under high-speed stirring. Then add 10 g of inorganic montmorillonite and disperse it using a SA30 high-speed disperser at 3000 rpm for 30 minutes until it becomes a uniform colloid. Modified montmorillonite (TW-MMT-20) can be obtained.

[0084] (3) Add 10 g of Tween 60 (TW-60) to 50 g of water and fully dissolve it under high-speed stirring. Then add 10 g of inorganic montmorillonite and disperse it using a SA30 high-speed disperser at 3000 rpm for 30 minutes until it becomes a uniform colloid. Modified montmorillonite (TW-MMT-100) can be obtained.

[0085] Example 2 Preparation of modified montmorillonite / epoxy resin cured product

[0086] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add the modified montmorillonite prepared in Example 1-(1) (the addition amount is 1% of the mass of epoxy resin E51), and disperse at a high speed of 1500 rpm for 30min at 60°C preheating condition to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a 60°C vacuum drying oven to remove the solvent and bubbles. Add 5g of polyamide 651 and 9.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain the modified montmorillonite / epoxy resin cured product TW-EP-1.

[0087] Example 3 Preparation of modified montmorillonite / epoxy resin cured product

[0088] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add the modified montmorillonite prepared in Example 1-(1) (the addition amount is 2% of the mass of epoxy resin E51), and disperse at a high speed of 1500 rpm for 30min at 60°C preheating condition to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a 60°C vacuum drying oven to remove solvent and bubbles. Add 15g of polyamide 651 and 7.4g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain the modified montmorillonite / epoxy resin cured product TW-EP-2.

[0089] Example 4 Preparation of modified montmorillonite / epoxy resin cured product

[0090] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add the modified montmorillonite prepared in Example 1-(1) (the addition amount is 4% of the mass of epoxy resin E51), and disperse at a high speed of 1500 rpm for 30min at 60°C preheating condition to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a 60°C vacuum drying oven to remove the solvent and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain the modified montmorillonite / epoxy resin cured product TW-EP-4-50.

[0091] Example 5 Preparation of modified montmorillonite / epoxy resin cured product

[0092] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add the modified montmorillonite prepared in Example 1-(2) (the addition amount is 4% of the mass of epoxy resin E51), and disperse at a high speed of 1500 rpm for 30min at 60°C preheating condition to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a 60°C vacuum drying oven to remove the solvent and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain the modified montmorillonite / epoxy resin cured product TW-EP-4-20.

[0093] Example 6 Preparation of modified montmorillonite / epoxy resin cured product

[0094] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add the modified montmorillonite prepared in Example 1-(3) (the addition amount is 4% of the mass of epoxy resin E51), and disperse at a high speed of 1500 rpm for 30min at 60°C preheating condition to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a 60°C vacuum drying oven to remove the solvent and bubbles. Add 10g of polyamide 651 and 8.5 diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain the modified montmorillonite / epoxy resin cured product TW-EP-4-100.

[0095] Comparative Example 1 Preparation of modified montmorillonite / epoxy resin cured product

[0096] The difference between this comparative example and Example 4 is that the montmorillonite is not modified.

[0097] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add inorganic montmorillonite (the amount added is 4% of the mass of epoxy resin E51), and disperse at 1500 rpm for 30min at a preheating temperature of 60°C to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a vacuum drying oven at 60°C to remove solvents and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain montmorillonite / epoxy resin cured product (T-EP).

[0098] Comparative Example 2 Preparation of modified montmorillonite / epoxy resin cured product

[0099] The difference between this comparative example and Example 4 is that the modifiers used to modify the montmorillonite are different.

[0100] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add modified montmorillonite (the amount added is 4% of the mass of epoxy resin E51), and disperse at 1500 rpm for 30min at a preheating temperature of 60°C to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a vacuum drying oven at 60°C to remove solvents and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain modified montmorillonite / epoxy resin cured product SP8-EP-4.

[0101] Wherein, the preparation method of modified montmorillonite is as follows:

[0102] Add 5g of Span 80 to 50g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10g of inorganic montmorillonite and disperse it at 3000 rpm for 30 minutes using a SA30 high-speed disperser to form a uniform colloid to obtain modified montmorillonite SP8-MMT-50.

[0103] Comparative Example 3 Preparation of modified montmorillonite / epoxy resin cured product

[0104] The difference between this comparative example and Example 4 is that the modifiers used to modify the montmorillonite are different.

[0105] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add modified montmorillonite (the amount added is 4% of the mass of epoxy resin E51), and disperse at 1500 rpm for 30min at a preheating temperature of 60°C to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a vacuum drying oven at 60°C to remove solvents and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain the modified montmorillonite / epoxy resin cured product TW-SP-EP-4.

[0106] Wherein, the preparation method of modified montmorillonite is as follows:

[0107] Add 3g Tween 60 and 2g Span 60 to 50g water, fully dissolve under high-speed stirring at 3000 rpm, then add 10g inorganic montmorillonite, use SA30 high-speed disperser at 3000 rpm for 30 minutes to form a uniform colloid, and then you can get modified montmorillonite.

[0108] Comparative Example 4 Preparation of modified montmorillonite / epoxy resin cured product

[0109] The difference between this comparative example and Example 4 is that the modifiers used to modify the montmorillonite are different.

[0110] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add modified montmorillonite (the amount added is 4% of the mass of epoxy resin E51), and disperse at 1500 rpm for 30min at a preheating temperature of 60°C to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a vacuum drying oven at 60°C to remove the solvent and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain modified montmorillonite / epoxy resin cured product SS-EP-4.

[0111] Wherein, the preparation method of modified montmorillonite is as follows:

[0112] Add 5g of sodium dodecylbenzene sulfonate to 50g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10g of inorganic montmorillonite and disperse it at 3000 rpm for 30 minutes using a SA30 high-speed disperser to form a uniform colloid to obtain modified montmorillonite.

[0113] Comparative Example 5 Preparation of modified montmorillonite / epoxy resin cured product

[0114] The difference between this comparative example and Example 4 is that the modifiers used to modify the montmorillonite are different.

[0115] Add 15g of ethanol to 100g of epoxy resin E51, stir mechanically for 30min at room temperature, then add modified montmorillonite (the amount added is 4% of the mass of epoxy resin E51), and disperse at 1500 rpm for 30min at a preheating temperature of 60°C to fully disperse the modified montmorillonite in the epoxy resin. Then, place the modified montmorillonite / epoxy resin in a vacuum drying oven at 60°C to remove solvents and bubbles. Add 10g of polyamide 651 and 8.5g of diethylenetriamine mixed curing agent, stir evenly at room temperature, and then stand to cure to obtain modified montmorillonite / epoxy resin cured product SP6-EP-4.

[0116] Wherein, the preparation method of modified montmorillonite is as follows:

[0117] Add 5g of Span 60 to 50g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10g of inorganic montmorillonite and disperse it at 3000 rpm for 30 minutes using a SA30 high-speed disperser to form a uniform colloid to obtain modified montmorillonite.

[0118] Example 7 Structural Characterization and Performance Testing of Modified Montmorillonite / Epoxy Resin Cured Material

[0119] (1) SEM: Scanning electron microscopy: Scan the fracture surface of the solidified material at a voltage of 10 kV to observe the dispersion of solid particles in the resin matrix.

[0120] Scanning electron microscopy is an effective technique for studying the dispersion properties of inorganic particles and the microscopic morphology of material surfaces. Figure 1As shown: (a) is a cross-sectional SEM image of montmorillonite / epoxy resin cured product (T-EP), and (b) is a cross-sectional SEM image of modified montmorillonite / epoxy resin cured product (TW-EP) prepared in Example 3. The cross section in (a) is relatively smooth, while in the cross section of the modified montmorillonite / epoxy resin cured product in (b), the interface between the particles and the cured product is in a dispersed state, indicating that the interface between the particles and the matrix resin has good compatibility. SEM microscopic morphology analysis further proves that the modified montmorillonite is easier to disperse in the epoxy resin matrix than the unmodified inorganic montmorillonite. It may be that after Tween-60 acts on montmorillonite, the ester group of Tween-60 reacts with montmorillonite, and the long fatty chain segment has good compatibility with epoxy resin, which improves the dispersibility of montmorillonite in epoxy resin. The increase in dispersibility makes the barrier performance of the modified montmorillonite in epoxy resin better, which is conducive to improving the thermal properties of the modified montmorillonite / epoxy resin cured product.

[0121] (2) DSC test: In N2 environment, the temperature was raised at a rate of 20°C / min and scanned to 200°C to test the glass transition temperature of the sample.

[0122] Figure 2 (a) is a DSC diagram of the glass transition temperature (Tg) of the modified montmorillonite / epoxy resin cured product prepared in Example 3. Figure 2 As shown in (a), when montmorillonite is not modified, the glass transition temperature of the DSC curve of the epoxy resin cured product is more obvious. This is because the thermal conductivity rate of the cured product is different after the addition of montmorillonite. Figure 2 (b) in the figure shows the change in glass transition temperature (Tg) of epoxy resin cured product before and after modification. Figure 2 (b) in the figure shows that the glass transition temperature of montmorillonite / epoxy resin cured product T-EP is 67°C, which is 3°C lower than that of pure epoxy resin cured product. However, the glass transition temperature (Tg) of modified montmorillonite / epoxy resin cured product TW-EP is higher, at 72°C. This is because after TW60 modification, the dispersibility of modified montmorillonite in epoxy resin is higher, and the heat barrier effect is improved. Therefore, the glass transition temperature (Tg) of modified montmorillonite / epoxy resin cured product TW-EP is higher than that of pure epoxy resin cured product (EP).

[0123] (3) TGA test: In an air environment, the thermal decomposition of the material is tested at a heating rate of 10°C / min in the range of room temperature to 800°C.

[0124] Table 1 shows the data of thermal weight loss of modified montmorillonite / epoxy resin cured product. It can be seen that the thermal decomposition temperature (Td50%) of the modified montmorillonite / epoxy resin cured product prepared in Example 3 is 410°C, and the residual carbon rate at 700°C is 3.79%, which are better than pure epoxy resin (EP) and unmodified montmorillonite epoxy resin cured product (T-EP). This is because the thermal decomposition of epoxy resin cured product before and after modification is mainly the degradation of epoxy resin cross-linking network, the montmorillonite in epoxy resin cured product has a barrier effect on heat conduction, and the modified montmorillonite is easier to disperse in epoxy resin, so the modified montmorillonite has a higher thermal barrier efficiency.

[0125] Table 1 Thermal properties of modified montmorillonite / epoxy resin cured products

[0126] serial number <![CDATA[T d 50% / ℃]]> 700℃ residual carbon rate / % EP 392 0.60％ T-EP 405 3.01％ TW-EP 410 3.79％

[0127] (4) Flame retardant performance test: The test sample size is 80mm×10mm×4mm specimen, and the flame retardant performance of the test material is tested.

[0128] The limiting oxygen index (LOI) specifies the ratio of oxygen to nitrogen that can just support combustion, and is an important indicator for characterizing flame retardancy. Table 2 gives the limiting oxygen index (LOI) test data. It can be seen that the limiting oxygen index (LOI) of both montmorillonite / epoxy resin cured product (T-EP) and modified montmorillonite / epoxy resin cured product (TW-EP) is higher than that of pure epoxy resin cured product (EP), and the improvement of the limiting oxygen index (LOI) of epoxy resin cured product by modified montmorillonite is more obvious. In addition, within the research range, with the increase of the content of modified montmorillonite in modified montmorillonite / epoxy resin cured product (TW-EP), the limiting oxygen index (LOI) of modified montmorillonite / epoxy resin cured product (TW-EP) gradually increases. This shows that adding modified montmorillonite can effectively improve the flame retardant properties of modified montmorillonite / epoxy resin cured product (TW-EP).

[0129] Table 2 Flame retardant properties of epoxy resin cured products

[0130]

[0131]

[0132] Example 8 Preparation of modified montmorillonite / waterborne epoxy anticorrosion coating

[0133] According to the amount shown in Table 3, ethanol solvent was added to the epoxy resin and stirred at room temperature for 30 minutes. Then modified montmorillonite (TW-MMT) (the percentage in the cured coating was 2%) and water were added, and the mixture was dispersed at 3000 rpm in a high-speed disperser for 1 hour to fully emulsify the epoxy resin and obtain a white epoxy resin emulsion. Then fillers and additives were added, and after uniform stirring and dispersion, a mixed curing agent of polyamide 651 and diethylenetriamine was added and stirred to obtain a modified montmorillonite / waterborne epoxy anticorrosion coating EP-2.

[0134] Table 3 Ratio of various substances in modified montmorillonite / waterborne epoxy anticorrosion coating

[0135]

[0136]

[0137] Example 9 Preparation of modified montmorillonite / waterborne epoxy anticorrosion coating

[0138] The difference between this embodiment and embodiment 8 is that the amount of modified montmorillonite added is different. In this embodiment, the amount of modified montmorillonite added is 7.45 g (the weight percentage in the cured coating is 4%), and modified montmorillonite / water-based epoxy anti-corrosion coating EP-4 is obtained.

[0139] Example 10 Preparation of modified montmorillonite / waterborne epoxy anticorrosion coating

[0140] The difference between this embodiment and embodiment 8 is that the amount of modified montmorillonite added is different. In this embodiment, the amount of modified montmorillonite added is 11.30 g (the weight percentage in the cured coating is 6%), and modified montmorillonite / water-based epoxy anti-corrosion coating EP-6 is obtained.

[0141] Example 11 Preparation of modified montmorillonite / waterborne epoxy anticorrosion coating

[0142] The difference between this embodiment and embodiment 8 is that the modified montmorillonite and its addition amount are different. The modified montmorillonite in this embodiment is the modified montmorillonite prepared in embodiment 1-(2), and its addition amount is 7.45g (the weight percentage in the cured coating is 4%), and a modified montmorillonite / water-based epoxy anti-corrosion coating EP-4(2) is obtained.

[0143] Example 12 Preparation of modified montmorillonite / waterborne epoxy anticorrosion coating

[0144] The difference between this embodiment and embodiment 8 is that the modified montmorillonite and its addition amount are different. The modified montmorillonite in this embodiment is the modified montmorillonite prepared in embodiment 1-(3), and its addition amount is 7.45g (the weight percentage in the cured coating is 4%), and a modified montmorillonite / water-based epoxy anti-corrosion coating EP-4(3) is obtained.

[0145] Comparative Example 6 Preparation of waterborne epoxy anti-corrosion coating

[0146] The difference between this comparative example and Example 8 is that no montmorillonite is added.

[0147] Comparative Example 7 Preparation of montmorillonite / waterborne epoxy anti-corrosion coating

[0148] The difference between this comparative example and Example 8 is that the montmorillonite is not modified.

[0149] Comparative Example 8 Preparation of modified montmorillonite / waterborne epoxy anti-corrosion coating

[0150] The difference between this comparative example and Example 9 is that the modifiers used to modify the montmorillonite are different.

[0151] That is, the preparation method of modified montmorillonite is as follows:

[0152] Add 5g of sodium dodecylbenzene sulfonate to 50g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10g of inorganic montmorillonite and disperse it with a SA30 high-speed disperser at 3000 rpm for 30 minutes to form a uniform colloid to obtain modified montmorillonite.

[0153] Comparative Example 9 Preparation of modified montmorillonite / waterborne epoxy anti-corrosion coating

[0154] The difference between this comparative example and Example 9 is that the modifiers used to modify the montmorillonite are different.

[0155] That is, the preparation method of modified montmorillonite is as follows:

[0156] Add 5g of Span 80 to 50g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10g of inorganic montmorillonite and disperse it with a SA30 high-speed disperser at 3000 rpm for 30 minutes until it becomes a uniform colloid to obtain modified montmorillonite.

[0157] Comparative Example 10 Preparation of modified montmorillonite / waterborne epoxy anti-corrosion coating

[0158] The difference between this comparative example and Example 9 is that the modifiers used to modify the montmorillonite are different.

[0159] That is, the preparation method of modified montmorillonite is as follows:

[0160] Add 5g of Span 60 to 50g of water and fully dissolve it under high-speed stirring at 3000 rpm. Then add 10g of inorganic montmorillonite and disperse it with a SA30 high-speed disperser at 3000 rpm for 30 minutes until it becomes a uniform colloid to obtain modified montmorillonite.

[0161] Comparative Example 11 Preparation of modified montmorillonite / waterborne epoxy anti-corrosion coating

[0162] The difference between this comparative example and Example 9 is that the modifiers used to modify the montmorillonite are different.

[0163] That is, the preparation method of modified montmorillonite is as follows:

[0164] Add 3g of Tween 80 and 2g of Span 60 to 50g of water, fully dissolve under high-speed stirring at 3000 rpm, then add 10g of inorganic montmorillonite, and disperse it with a SA30 high-speed disperser at 3000 rpm for 30 minutes to form a uniform colloid to obtain modified montmorillonite.

[0165] Example 13 Performance Test

[0166] The waterborne epoxy anti-corrosion coatings prepared in Examples 8-12 and Comparative Examples 6-11 were coated on pre-treated tinplate substrates using a wire rod coater and dried at room temperature to form a film. The coatings were cured according to the requirements of the following relevant standards, and the relevant properties were tested:

[0167] Surface drying time: Determined by the finger drying method in GB / T1728-2020 "Determination of drying time of paint and putty films";

[0168] Pencil hardness: Determined in accordance with GB / T6739-2006 "Paints and varnishes: Determination of film hardness by pencil method";

[0169] Impact resistance: Tested using GB / T1732-2020 "Determination of flexible impact resistance of paint film";

[0170] Alkali resistance: According to the alkali resistance test of coating in GBT22374-2018 "Floor Coating Materials": Soak in saturated Ca(OH)2 solution for 48 hours;

[0171] Acid resistance: Refer to the coating acid resistance test in GBT22374-2018 "Floor Coating Materials": Soak in 10% H2SO4 solution for 48 hours;

[0172] Salt water resistance: According to the coating salt water resistance test in GBT22374-2018 "Floor Coating Materials": Soak in 3% NaCl solution for 168 hours.

[0173] The results and analysis are as follows:

[0174] (1) The surface properties, pencil hardness and impact resistance of the coating are shown in Table 4.

[0175] Table 4 Surface properties of modified montmorillonite / waterborne epoxy anticorrosion coatings

[0176]

[0177]

[0178] As can be seen from Table 4 results, no matter it is the coating of pure epoxy coating (EP), or the coating of modified montmorillonite / waterborne epoxy anticorrosion coating, its surface drying time is all within 2 hours (except embodiment 12), and the level of hard work can be reached at room temperature within 24 hours. The modified montmorillonite / waterborne epoxy anticorrosion coating of preparation is normal in appearance, and the surface coating film is normal, without bubbles, cracks, and pinhole-free phenomenon. The surface drying time of the coating of the waterborne epoxy anticorrosion coating prepared by sodium dodecylbenzene sulfonate modified montmorillonite in the comparative example is 2.5 hours, and the coating surface of the waterborne epoxy anticorrosion coating prepared by Span-80 and Span 60 modified montmorillonite is relatively rough.

[0179] From the perspective of the impact resistance and pencil hardness of the coating, with the increase of the amount of modified montmorillonite added, it shows a trend of first increasing and then decreasing. When the amount of modified montmorillonite added in the cured layer is 4wt% (EP-4), the pencil hardness of the modified montmorillonite / waterborne epoxy anti-corrosion coating is 3H and the impact resistance is 55cm, which is significantly better than that of pure epoxy coating. It can be seen that a specific amount of modified montmorillonite can improve the coating mechanical properties of waterborne epoxy anti-corrosion coatings.

[0180] (2) The acid and alkali resistance of the coating is shown in Table 5.

[0181] Table 5 Acid and alkali resistance of modified montmorillonite / waterborne epoxy anti-corrosion coating

[0182]

[0183]

[0184] Powdering: The more +'s there are, the more powdering the coating will shed after immersion.

[0185] The results show that after the epoxy coating before and after the addition of modified montmorillonite is immersed in 10% H2SO4 solution for 48 hours, or in saturated Ca(OH)2 solution for 48 hours, the coating is normal in appearance, without peeling, falling off, or blistering. In terms of powdering performance, the performance of the epoxy coating with the addition of modified montmorillonite is obviously better than that before modification. When the addition amount of modified montmorillonite is increased to 6% (EP-6), the modified montmorillonite epoxy coating turns white slightly after immersion, indicating that the appropriate addition of modified montmorillonite can improve the acid and alkali resistance of the epoxy coating. However, the sodium dodecylbenzene sulfonate modified montmorillonite in the comparative example, as well as the Span-80 and Span-60 modified montmorillonites, cannot improve the acid and alkali resistance of the waterborne epoxy anticorrosion coating, and even have a negative impact on its acid and alkali resistance.

[0186] (3) The salt water resistance of the coating is shown in Table 6.

[0187] Table 6 Salt water resistance of modified montmorillonite / waterborne epoxy anticorrosion coating

[0188]

[0189] The results show that after the modified montmorillonite / waterborne epoxy anti-corrosion coating was immersed in 3% NaCl for 168 hours, the coating had a normal appearance, without peeling, shedding, or blistering. However, as far as blistering is concerned, as the amount of modified montmorillonite added to the system increases, the blistering of the coating after immersion first decreases and then increases. When the content of modified montmorillonite in the cured layer is 6wt% (EP-6), the surface turns slightly white after immersion. This indicates that adding an appropriate amount of modified montmorillonite can improve the salt water resistance of the epoxy coating. However, the sodium dodecylbenzene sulfonate modified montmorillonite in the comparative example, as well as the Span-80 and Span-60 modified montmorillonite, cannot improve the salt water resistance of the waterborne epoxy anti-corrosion coating, and even have a negative impact on its salt water resistance.

[0190] (4) Heat resistance of coating

[0191] The glass transition temperatures (T) of pure epoxy coating (EP) and modified montmorillonite / waterborne epoxy coating were tested according to the method in Example 7. g ), the results show that ( Figure 3 ) The coating glass transition temperature (T) of the modified montmorillonite / waterborne epoxy coating (EP-4) when the addition amount of the modified montmorillonite in the cured layer is 4 wt% g ) is 73°C, which is higher than the glass transition temperature (T g )70℃ is improved, which shows that the modified montmorillonite of the present invention can improve the heat resistance of the epoxy anti-corrosion coating.

[0192] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A modified montmorillonite, characterized in that: The invention is prepared from Tween 60 and montmorillonite; the mass ratio of Tween 60 to montmorillonite is 1:1-5, preferably 1:1.5-2.5, and more preferably 1:1.8-2.

2.

2. A method for preparing the modified montmorillonite according to claim 1, characterized in that: The steps include: The Tween 60 is added into water, stirred and dissolved, and then montmorillonite is added and dispersed at high speed for 20 minutes to 60 minutes to obtain the modified montmorillonite; Preferably, the mass ratio of Tween 60 to water is 1:8-12; Preferably, the rotation speed of the high-speed dispersion is 2500 rpm-3500 rpm.

3. Use of the modified montmorillonite according to claim 1 as a flame retardant in the preparation of heat-resistant and flame-retardant epoxy resin.

4. Use of the modified montmorillonite according to claim 1 as an antiseptic in the preparation of waterborne epoxy anticorrosion coatings.

5. A heat-resistant and flame-retardant modified montmorillonite / epoxy resin cured product, characterized in that: The composition is prepared from the following raw materials in parts by weight: Preferably, the epoxy resin is selected from one or more of bisphenol A epoxy resin and novolac epoxy resin, more preferably epoxy resin E51 and / or epoxy resin E54; Preferably, the curing agent is selected from at least one of 4,4'-diaminodiphenylmethane, phenolic resin, diethylenetriamine and polyamide, preferably diethylenetriamine and / or polyamide YK651.

6. The heat-resistant and flame-retardant modified montmorillonite / epoxy resin cured product according to claim 5, characterized in that: The composition is prepared from the following raw materials in parts by weight: Preferably, the modified montmorillonite is added in an amount of 1-12 wt % of the epoxy resin, preferably 1-10 wt %, 1-6 wt %, more preferably 2-5 wt %, more preferably 3.5-4.5 wt %.

7. A method for preparing the heat-resistant and flame-retardant modified montmorillonite / epoxy resin cured product according to claim 5 or 6, characterized in that: The steps include: The epoxy resin is dissolved in ethanol, and then the modified montmorillonite is added, and the mixture is dispersed at 55°C-65°C for 20min-40min to remove the solvent and bubbles; then the curing agent is added, and the mixture is stirred evenly and allowed to stand for curing to obtain the modified montmorillonite / epoxy resin cured product; Preferably, the removal of solvent and bubbles is carried out in a vacuum drying oven at 55°C-65°C; Preferably, the dispersion rotation speed is 1200 rpm-1800 rpm.

8. A modified montmorillonite / waterborne epoxy anti-corrosion coating, characterized in that: The composition is prepared from the following raw materials in parts by weight: Preferably, the epoxy resin is epoxy resin E51 or epoxy resin E54, more preferably epoxy resin E51; Preferably, the curing agent is selected from diethylenetriamine and / or polyamide, preferably a combination of diethylenetriamine and polyamide YK651; Preferably, the filler is selected from any two or a mixture of two or more of calcium carbonate, silicon powder, silicon dioxide, talc, titanium dioxide, zinc oxide, zinc phosphate, red iron oxide and mica powder; Preferably, the auxiliary agent is selected from at least one of a leveling agent, a wetting agent, a thickener and a defoaming agent; Preferably, the wetting agent is one or a mixture of more than one of TEGO450, BYK346 and K-LS315; Preferably, the thickener is one or a mixture of more than one of hydroxyethyl cellulose, hydroxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose and sodium carboxymethyl cellulose; Preferably, the defoamer is a mineral oil defoamer, a polysiloxane defoamer, or a mixture of one or more of an amine, imine, or amide defoamer, more preferably BYK-024, BEK-760, or BKY-066 or a mixture of one or more of the above; Preferably, the leveling agent is PW336.

9. The modified montmorillonite / waterborne epoxy anticorrosion coating according to claim 8, characterized in that: The product is prepared from the following raw materials by weight: Preferably, the modified montmorillonite is added in an amount of 1-6 wt % of the weight of the solidified layer, more preferably 2-5 wt %, and more preferably 3.5-4.5 wt %.

10. A method for preparing the modified montmorillonite / waterborne epoxy anticorrosion coating according to claim 8 or 9, characterized in that: The steps include: The epoxy resin is dissolved in ethanol, and then water and the modified montmorillonite are added, and the epoxy resin is dispersed at a high speed for 50 minutes to 80 minutes to fully emulsify the epoxy resin. The filler and the auxiliary agent are added to the obtained epoxy resin emulsion, and the dispersion is uniform. Then, the curing agent is added and stirred uniformly to obtain the modified montmorillonite / waterborne epoxy anti-corrosion coating.

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