New type of additive for acid and corrosion resistant fluorocarbon coating, its preparation method and application

Abstract

The application discloses a new type of additive for acid-resistant and corrosion-resistant fluorocarbon paint and a preparation method and application thereof. The additive is obtained by chemical reaction of isocyanate compounds and amino-terminated liquid butadiene-acrylonitrile rubber under a nitrogen atmosphere. One end of the additive molecule contains isocyanate, which is compatible with fluorocarbon resin. The amino group at the other end can perform ring-opening reaction with the epoxy group of epoxy resin, thereby improving the dispersibility and compatibility of the epoxy resin in the fluorocarbon resin system. The fluorocarbon / epoxy composite resin obtained by using the new type of additive has adhesion reaching 0 level, and the acid resistance and corrosion resistance are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of coating materials technology, specifically to a novel additive for acid- and corrosion-resistant fluorocarbon coatings, its preparation method, and its application. Background Technology

[0002] Ship components and marine facilities exposed to complex environments for extended periods often suffer severe corrosion and wear damage during use. Protecting them with coatings is crucial for extending their service life. Fluorocarbon (FEVE) coatings, due to their unique physicochemical properties—low surface energy, high chemical inertness, high thermal stability, and low dielectric constant—are widely used as substrate protective coating materials. Furthermore, the presence of fluorine atoms in fluorocarbon coatings imparts a degree of lubrication, and the exposed carbon-fiber bonds further reduce the surface energy, resulting in excellent friction reduction and corrosion resistance under complex operating conditions such as washing and handling. However, pure fluorocarbon coatings suffer from poor strength, durability, and adhesion to the substrate, leading to cracking or peeling. This makes the substrate susceptible to erosion, wear, deformation, and cracking, ultimately compromising the coating's protective and barrier properties.

[0003] Epoxy resin (EP) possesses unique physicochemical properties, heat resistance, and chemical resistance, exhibiting excellent adhesion to metal substrates and is widely used in coatings and adhesives. Using epoxy resin as a blending modifier can increase the crosslinking density of inert fluorocarbon resin coatings and improve the adhesion between the coating and the metal substrate. However, due to its structural differences from fluorocarbon resin, epoxy resin is either immiscible or only partially miscible with fluorocarbon resin, leading to structural damage and performance degradation.

[0004] In conclusion, there is an urgent need for an additive that can make two resins miscible, possessing both good adhesion and acid and corrosion resistance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a novel additive for acid- and corrosion-resistant fluorocarbon coatings, its preparation method, and its application.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing an additive for acid- and corrosion-resistant fluorocarbon coatings, comprising:

[0008] Aminobutadiene-butadiene-acrylonitrile rubber (ATBN) is dissolved in xylene, then isocyanate compounds and catalysts are added, and the mixture is heated to 50-100℃ and stirred (200-600 rpm / min) under a nitrogen atmosphere for 1-3 hours until the isocyanate compounds are completely reacted. The reaction is then stopped to obtain the aforementioned additive.

[0009] The molecular weight of amino-terminated nitrile butadiene rubber is between 3500 and 10000;

[0010] The preferred mass ratio of amino-terminated nitrile rubber, xylene, and isocyanate compounds is 2-3:1-3:2-4;

[0011] The isocyanate compounds are selected from one or more of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), and hexamethylene diisocyanate (HDI);

[0012] The catalyst is selected from one or two of dibutyltin dilaurate and stannous isooctanoate; the amount of catalyst added is 0.1-0.5% of the total mass of the amino-terminated butadiene nitrile rubber and isocyanate compounds.

[0013] This invention relates to the additives prepared by the above-described method.

[0014] The additives described in this invention can be used in acid- and corrosion-resistant fluorocarbon coatings.

[0015] This invention also relates to a fluorocarbon coating, made from fluorocarbon resin, xylene, n-butanol, epoxy resin, and the additives of this invention;

[0016] The preferred mass ratio of fluorocarbon resin, xylene, n-butanol, and epoxy resin is 60:15:5:20.

[0017] Preferably, the amount of the additive of the present invention is 5-10% of the total mass of fluorocarbon resin and epoxy resin.

[0018] The preparation method of the fluorocarbon coating is as follows:

[0019] Fluorocarbon resin, xylene, and n-butanol are mixed and dissolved, and epoxy resin is added dropwise while stirring. Then, additives are added, and the mixture is heated to 90°C and reacted for 4 hours to obtain the fluorocarbon coating.

[0020] The technical principles of this invention include:

[0021] The additive of this invention is obtained by chemically reacting isocyanate compounds and amino-terminated liquid nitrile rubber under a nitrogen atmosphere. One end of the additive molecule contains an isocyanate, which is compatible with fluorocarbon resins, while the amino group at the other end can undergo a ring-opening reaction with the epoxy groups of epoxy resins, thereby improving the dispersibility and compatibility of epoxy resins in fluorocarbon resin systems. Fluorocarbon coatings made using this additive as a compatibilizer exhibit significantly enhanced adhesion to metal substrates and markedly improved acid and corrosion resistance.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention provides a novel additive for acid- and corrosion-resistant fluorocarbon coatings. This additive can improve the compatibility between fluorocarbon resin FEVE and epoxy resin. The fluorocarbon / epoxy composite resin obtained by using the novel additive has an adhesion grade of 0 and significantly improved acid and corrosion resistance. Attached Figure Description

[0024] Figure 1 Infrared spectrum of the adjuvant in Example 1 of this invention.

[0025] Figure 2 The mixed resin of Example 1 and Comparative Example 1 of this invention.

[0026] Figure 3 Example 1: Surface morphology of composite coating after immersion in 10wt% HCl for 48 hours.

[0027] Figure 4 Example 2: Surface morphology of composite coating after immersion in 10wt% HCl for 48 hours.

[0028] Figure 5 Example 3: Surface morphology of composite coating after immersion in 10wt% HCl for 48 hours.

[0029] Figure 6 Comparative Example 1: Surface morphology of composite coating immersed in 10wt% HCl for 48 hours. Detailed Implementation

[0030] The present invention is further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0031] In the following embodiments,

[0032] Amino-terminated butadiene nitrile rubber (ATBN) is from Junmei Engineering Plastics;

[0033] The oil-based fluorocarbon resin (FEVE) is from Asahi Glass Chemicals Co., Ltd.

[0034] The epoxy resin (E51) is from Jiangsu Dandelion New Materials.

[0035] The isocyanate curing agent is from Runyou Chemical Co., Ltd.

[0036] Example 1

[0037] Take 30g of amino-terminated nitrile butadiene rubber (ATBN), add it to a three-necked flask and dissolve it completely with 30g of xylene. After the rubber is completely dissolved, add 40g of diphenylmethane diisocyanate (MDI) and 1g of dibutyltin dilaurate at a stirring speed of 300rpm / min. Keep warm at 80℃ for 2h under a nitrogen atmosphere to obtain a novel resin additive.

[0038] Infrared results of the additives are as follows Figure 1 As shown, 2274cm -1 There was no -NCO stretching vibration peak at 1725 cm⁻¹, indicating that the surface MDI had completely reacted. -1 The absorption peak is a characteristic peak of the carbonyl C=O group, 2238 cm⁻¹. -1 The absorption peak at this point is a characteristic peak of -CN in ATBN, which indicates that MDI and ATBN have completely reacted.

[0039] 60g of commercially available oily fluorocarbon resin (FEVE), 15g of xylene, and 5g of n-butanol were added to a three-necked flask and heated to 60℃ to dissolve. After the resin was completely dissolved, 20g of epoxy resin (E51) was slowly added dropwise while stirring at 400rpm / min. After stirring for 1 hour, the solution became cloudy, yielding the initial product. Subsequently, a novel resin additive was added, with the amount of the additive being 10wt% of the total resin. The mixture was heated to 90℃ and reacted for 4 hours. The solution became clear again, yielding a novel acid- and corrosion-resistant composite resin. Figure 2 As shown.

[0040] 0.5g of isocyanate curing agent and 1g of novel acid- and corrosion-resistant composite resin were physically mixed and then applied to a substrate using a scraper, resulting in a coating thickness of 20μm. The mixture was then placed in a drying oven at 60℃ for 2 hours to cure, yielding the novel acid- and corrosion-resistant composite coating.

[0041] Example 2

[0042] Take 30g of amino-terminated nitrile butadiene rubber (ATBN), add it to a three-necked flask and dissolve it completely with 30g of xylene. After the rubber is completely dissolved, add 40g of hexamethylene diisocyanate (HDI) and 1g of dibutyltin dilaurate at a stirring speed of 300rpm / min. Keep warm at 80℃ for 2h under a nitrogen atmosphere to obtain a novel resin additive.

[0043] Take 60g of commercially available oily fluorocarbon resin (FEVE), 15g of xylene and 5g of n-butanol and add them to a three-necked flask. Heat to 60℃ and dissolve. After the resin is completely dissolved, slowly add 20g of epoxy resin (E51) dropwise at a stirring speed of 400rpm / min. After stirring for 1h, the solution becomes turbid, and the initial product is obtained. Then add a new type of resin additive, the amount of which is 10wt% of the total amount of resin. Heat to 90℃ and react for 4h. The solution becomes clear again, and a new type of acid-resistant and corrosion-resistant composite resin is obtained.

[0044] 0.5g of isocyanate curing agent and 1g of novel acid- and corrosion-resistant composite resin were physically mixed and then applied to a substrate using a scraper, resulting in a coating thickness of 20μm. The mixture was then placed in a drying oven at 60℃ for 2 hours to cure, yielding the novel acid- and corrosion-resistant composite coating.

[0045] Example 3

[0046] Take 30g of amino-terminated nitrile butadiene rubber (ATBN), add it to a three-necked flask and dissolve it completely with 30g of xylene. After the rubber is completely dissolved, add 40g of diphenylmethane diisocyanate (MDI) and 1g of dibutyltin dilaurate at a stirring speed of 300rpm / min. Keep warm at 80℃ for 2h under a nitrogen atmosphere to obtain a novel resin additive.

[0047] Take 60g of commercially available oily fluorocarbon resin (FEVE), 15g of xylene and 5g of n-butanol and add them to a three-necked flask. Heat to 60℃ and dissolve. After the resin is completely dissolved, slowly add 20g of epoxy resin (E51) dropwise at a stirring speed of 400rpm / min. After stirring for 1h, the solution becomes turbid, and the initial product is obtained. Then add a new type of resin additive, the amount of which is 5wt% of the total amount of resin. Heat to 90℃ and react for 4h. The solution becomes clear again, and a new type of acid-resistant and corrosion-resistant composite resin is obtained.

[0048] 0.5g of isocyanate curing agent and 1g of novel acid- and corrosion-resistant composite resin were physically mixed and then applied to a substrate using a scraper, resulting in a coating thickness of 20μm. The mixture was then placed in a drying oven at 60℃ for 2 hours to cure, yielding the novel acid- and corrosion-resistant composite coating.

[0049] Comparative Example 1

[0050] Take 60g of commercially available oily fluorocarbon resin (FEVE), 15g of xylene, and 5g of n-butanol and add them to a three-necked flask. Heat to 60℃ to dissolve. After the resin is completely dissolved, slowly add 20g of epoxy resin (E51) dropwise while stirring at 400rpm / min to obtain a mixed resin, as shown below. Figure 2 As shown.

[0051] After physically mixing 0.5g of isocyanate curing agent with 1g of composite resin, the mixture was applied to the substrate using a blade coater, resulting in a coating thickness of 20μm. The substrate was then placed in a drying oven at 60℃ for 2 hours to cure, yielding the composite coating.

[0052] The composite coatings obtained above were subjected to acid resistance, corrosion resistance, and impact resistance tests on each sample according to B / T9274-1988, GB / T1732-1993, GB / T 9286―1998, and an electrochemical workstation. The results are compared in Table 1. Figures 3-6 As shown.

[0053] Table 1. Basic performance tests of each coating.

[0054]

[0055]

[0056] As can be seen from Examples 1, 2, 3 and Comparative Example 1, the novel resin additive prepared in this invention can improve the compatibility of fluorocarbon resin and epoxy resin, so that the resin composite of the two has good acid resistance, corrosion resistance and excellent impact resistance, the coating is not easily damaged, and it can play a good protective role for the matrix material.

Claims

1. A fluorocarbon coating, characterized in that, It is made from fluorocarbon resin, xylene, n-butanol, epoxy resin, and additives. The preparation method of the auxiliary agent is as follows: The amino-terminated nitrile rubber was dissolved in xylene, then isocyanate compounds and catalyst were added, and the mixture was heated to 50-100℃ under a nitrogen atmosphere and stirred for 1-3 hours until the isocyanate compounds were completely reacted. The reaction was then stopped to obtain the aforementioned additive. The molecular weight of amino-terminated nitrile butadiene rubber is between 3500 and 10000; The isocyanate compound is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate; The mass ratio of amino-terminated nitrile rubber, xylene, and isocyanate compounds is 2-3:1-3:2-4; The catalyst is selected from one or both of dibutyltin dilaurate and stannous isooctanoate.

2. The fluorocarbon coating as described in claim 1, characterized in that, In the preparation method of the additive, the amount of catalyst added is 0.1-0.5% of the total mass of the amino-terminated butadiene nitrile rubber and isocyanate compounds.

3. The fluorocarbon coating as described in claim 1, characterized in that, The mass ratio of fluorocarbon resin, xylene, n-butanol, and epoxy resin is 60:15:5:20; the amount of additives is 5-10% of the total mass of fluorocarbon resin and epoxy resin.

4. The method for preparing fluorocarbon coating as described in claim 1, characterized in that, The method is as follows: Fluorocarbon resin, xylene, and n-butanol are mixed and dissolved, and epoxy resin is added dropwise while stirring. Then, additives are added, and the mixture is heated to 90°C and reacted for 4 hours to obtain the fluorocarbon coating.

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