Novel auxiliary agent for acid-resistant and corrosion-resistant fluorocarbon coating as well as preparation method and application of novel auxiliary agent

Abstract

The invention discloses a novel auxiliary agent for acid-resistant and corrosion-resistant fluorocarbon paint and a preparation method and application thereof.The auxiliary agent is obtained through a chemical reaction of an isocyanate compound and amino-terminated liquid nitrile rubber in the nitrogen atmosphere, one end of an auxiliary agent molecule contains isocyanate, the auxiliary agent molecule can be compatible with fluorocarbon resin, and the auxiliary agent molecule has the advantages of being good in acid resistance, corrosion resistance and corrosion resistance. The amino group at the other end can be subjected to a ring-opening reaction with the epoxy group of the epoxy resin, so that the dispersity and compatibility of the epoxy resin in a fluorocarbon resin system are improved, the adhesion of the fluorocarbon / epoxy composite resin obtained by using the novel auxiliary agent reaches grade 0, and the acid resistance and corrosion resistance are obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coating materials, and in particular to a novel additive for acid-resistant and corrosion-resistant fluorocarbon coatings, and a preparation method and application thereof. Background Art

[0002] Ship parts and marine facilities that are exposed to complex environments for a long time are often severely corroded and worn during use, and using coatings to protect them is an important means to extend their service life. Fluorocarbon (FEVE) coatings are widely used as substrate protective coating materials due to their unique physical and chemical properties, such as low surface energy, high chemical inertness, high thermal stability, and low dielectric constant. In addition, the presence of F atoms in fluorocarbon coatings also gives the coatings a certain lubricity, and the CF bonds exposed on the surface can further reduce the surface energy of the coatings, making the coatings exhibit good friction reduction and corrosion resistance under complex working conditions such as water washing and operation. However, the strength and durability of pure fluorocarbon coatings, as well as their poor adhesion to the substrate material, can lead to cracking or peeling between the coating and the substrate, making the substrate susceptible to erosion and wear, as well as deformation and cracking, thereby damaging the protective and barrier properties of the coating.

[0003] Epoxy resin (EP) has unique physical and chemical properties, heat resistance and chemical resistance, and has good adhesion to metal substrates. It is widely used in coatings and adhesives. Using epoxy resin as a blending modified resin can increase the crosslinking density of fluorocarbon resin-based inert coating materials and improve the adhesion between the coating and the metal substrate. However, using epoxy resin as a blending modified resin, due to its different structure with fluorocarbon resin, the two cannot be miscible or only partially miscible, resulting in structural damage and reduced performance.

[0004] In summary, there is an urgent need for an additive that can make the two resins miscible, so that they have good adhesion and are acid and corrosion resistant. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a new additive for acid-resistant and corrosion-resistant fluorocarbon coatings, and a preparation method and application thereof.

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

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

[0008] Dissolve the amino-terminated nitrile rubber (ATBN) in xylene, then add the isocyanate compound and the catalyst, heat to 50-100° C. in a nitrogen atmosphere, stir (200-600 rpm / min), react for 1-3 hours, until the isocyanate compound reacts completely, stop the reaction, and obtain the auxiliary agent;

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

[0010] Preferably, the mass ratio of the amino-terminated nitrile rubber, xylene, and isocyanate compound is 2-3:1-3:2-4;

[0011] The isocyanate compound is 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 both of dibutyltin dilaurate and stannous isooctanoate; the added amount of the catalyst is 0.1-0.5% of the total mass of the amino-terminated nitrile rubber and the isocyanate compound.

[0013] The present invention relates to an auxiliary agent prepared by the preparation method.

[0014] The auxiliary agent of the invention can be used in acid-resistant and corrosion-resistant fluorocarbon coatings.

[0015] The present invention also relates to a fluorocarbon coating, which is made of fluorocarbon resin, xylene, n-butanol, epoxy resin and the additive of the present invention as raw materials;

[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 auxiliary agent of the present invention is 5-10% of the total mass of the fluorocarbon resin and the epoxy resin.

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

[0019] The fluorocarbon resin, xylene and n-butanol are mixed and dissolved, epoxy resin is added dropwise under stirring, and then an auxiliary agent is added, and the temperature is raised to 90° C. to react for 4 hours to obtain the fluorocarbon coating.

[0020] The technical principles of the present invention include:

[0021] The auxiliary agent of the present invention is obtained by chemically reacting an isocyanate compound with an amino-terminated liquid nitrile rubber under a nitrogen atmosphere. One end of the auxiliary agent molecule contains an isocyanate, which can be compatible with the fluorocarbon resin, and the amino group at the other end can undergo a ring-opening reaction with the epoxy group of the epoxy resin, thereby improving the dispersibility and compatibility of the epoxy resin in the fluorocarbon resin system. The fluorocarbon coating prepared by using it as a compatibilizer has greatly enhanced adhesion to the metal substrate, and significantly improved acid resistance and corrosion resistance.

[0022] The beneficial effects of the present invention are:

[0023] The present invention provides a novel additive for acid-resistant and corrosion-resistant fluorocarbon coatings, which 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 of level 0, and the acid resistance and corrosion resistance are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : Infrared spectrum of the auxiliary agent of Example 1 of the present invention.

[0025] Figure 2 : The mixed resin of Example 1 of the present invention and Comparative Example 1.

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

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

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

[0029] Figure 6 : Surface morphology of the composite coating of Comparative Example 1 immersed in 10wt% HCl for 48H. DETAILED DESCRIPTION

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

[0031] In the following embodiments,

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

[0033] Oily fluorocarbon resin (FEVE) was from Asahi Glass Chemicals Co., Ltd.;

[0034] Epoxy resin (E51) was from Jiangsu Dandelion New Materials;

[0035] Isocyanate curing agent was from Runyou Chemical Co., Ltd.

[0036] Example 1

[0037] Take 30g of amino-terminated nitrile rubber (ATBN), add it into 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, and keep warm at 80℃ for 2h under a nitrogen atmosphere to obtain a new resin additive.

[0038] The infrared results of additives are as follows Figure 1 As shown, 2274cm -1 There is no -NCO stretching vibration peak at 1725cm -1 The absorption peak belongs to the characteristic peak of carbonyl C=O, 2238cm -1 The absorption peak at is the characteristic peak of -CN in ATBN, from which it can be analyzed that MDI and ATBN have completely reacted.

[0039] Take 60g of commercially available oily fluorocarbon resin (FEVE), 15g of xylene and 5g of n-butanol, add them into a three-necked flask and heat (60°C) to dissolve. After the resin is completely dissolved, slowly add 20g of epoxy resin (E51) at a stirring speed of 400rpm / min. After stirring for 1h, the solution becomes turbid to obtain the initial product. Then, add the new resin additive, the amount of the new additive is 10wt% of the total amount of the resin, heat to 90°C and react for 4h, the solution becomes clear again, and a new acid-resistant and corrosion-resistant composite resin is obtained. Figure 2 shown.

[0040] 0.5g of isocyanate curing agent was physically mixed with 1g of the new acid-resistant and corrosion-resistant composite resin, and then coated on the substrate using a scraper, with a coating thickness of 20μm. It was then placed in a drying oven at 60°C for 2h to obtain a new acid-resistant and corrosion-resistant composite coating.

[0041] Example 2

[0042] Take 30g of amino-terminated nitrile rubber (ATBN), add it into 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, and keep warm at 80℃ for 2h under a nitrogen atmosphere to obtain a new resin additive.

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

[0044] 0.5g of isocyanate curing agent was physically mixed with 1g of the new acid-resistant and corrosion-resistant composite resin, and then coated on the substrate using a scraper, with a coating thickness of 20μm. It was then placed in a drying oven at 60°C for 2h to obtain a new acid-resistant and corrosion-resistant composite coating.

[0045] Example 3

[0046] Take 30g of amino-terminated nitrile rubber (ATBN), add it into 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, and keep warm at 80℃ for 2h under a nitrogen atmosphere to obtain a new resin additive.

[0047] Take 60g of commercially available oily fluorocarbon resin (FEVE), 15g of xylene and 5g of n-butanol, add them into a three-necked flask and heat (60°C) to dissolve. After the resin is completely dissolved, slowly add 20g of epoxy resin (E51) at a stirring speed of 400rpm / min. After stirring for 1h, the solution becomes turbid to obtain the initial product. Subsequently, a new resin additive is added, the amount of the new additive is 5wt% of the total amount of the resin, the temperature is raised to 90°C and the reaction is carried out for 4h. The solution becomes clear again to obtain a new acid-resistant and corrosion-resistant composite resin.

[0048] 0.5g of isocyanate curing agent was physically mixed with 1g of the new acid-resistant and corrosion-resistant composite resin, and then coated on the substrate using a scraper, with a coating thickness of 20μm. It was then placed in a drying oven at 60°C for 2h to obtain a new acid-resistant and corrosion-resistant composite coating.

[0049] Comparative Example 1

[0050] 60 g of commercially available oily fluorocarbon resin (FEVE), 15 g of xylene and 5 g of n-butanol were added to a three-necked flask and heated (60°C) to dissolve. After the resin was completely dissolved, 20 g of epoxy resin (E51) was slowly added dropwise at a stirring speed of 400 rpm / min to obtain a mixed resin such as Figure 2 shown.

[0051] 0.5 g of isocyanate curing agent was physically mixed with 1 g of composite resin, and then coated on the substrate using a scraper, with a coating thickness of 20 μm. The composite coating was then cured in a drying oven at 60° C. for 2 h to obtain a composite coating.

[0052] The composite coating obtained above was tested for acid corrosion resistance and impact resistance according to B / T9274-1988, GB / T1732-1993, GB / T 9286-1998 and electrochemical workstation. The results are shown in Table 1. Figure 3-Figure 6 shown.

[0053] Table 1 Basic performance test of each coating

[0054]

[0055]

[0056] It can be seen from Example 1, Example 2, Example 3 and Comparative Example 1 that the new resin additive prepared in the present invention can improve the compatibility of fluorocarbon resin and epoxy resin, so that the composite resin of the two has good acid resistance, corrosion resistance and excellent impact resistance, the coating is not easy to be damaged, and can play a good protective role on the base material.

Claims

1. A method for preparing an additive for acid-resistant and corrosion-resistant fluorocarbon coatings, characterized in that: The method comprises: Dissolve the amino-terminated nitrile rubber in xylene, then add the isocyanate compound and the catalyst, heat to 50-100° C. in a nitrogen atmosphere, stir and react for 1-3 hours until the isocyanate compound reacts completely, stop the reaction, and obtain the auxiliary agent; The isocyanate compound is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate; The catalyst is selected from one or both of dibutyltin dilaurate and stannous isooctanoate.

2. The method for preparing an additive for acid-resistant and corrosion-resistant fluorocarbon coating according to claim 1, characterized in that: The molecular weight of amino-terminated nitrile rubber is between 3500 and 10000.

3. The method for preparing an additive for acid-resistant and corrosion-resistant fluorocarbon coating according to claim 1, characterized in that: The mass ratio of the amino-terminated nitrile rubber, xylene and isocyanate compound is 2-3:1-3:2-4.

4. The method for preparing an additive for acid-resistant and corrosion-resistant fluorocarbon coating according to claim 1, characterized in that: The added amount of the catalyst is 0.1-0.5% of the total mass of the amino-terminated nitrile rubber and the isocyanate compound.

5. The auxiliary agent obtained by the preparation method according to any one of claims 1 to 4.

6. Use of the auxiliary agent as claimed in claim 5 in acid-resistant and corrosion-resistant fluorocarbon coatings.

7. A fluorocarbon coating, characterized in that: The invention is prepared from fluorocarbon resin, xylene, n-butanol, epoxy resin and the auxiliary agent as claimed in claim 5 as raw materials.

8. The fluorocarbon coating according to claim 7, characterized in that: The mass ratio of fluorocarbon resin, xylene, n-butanol and epoxy resin is 60:15:5:20; the amount of the auxiliary agent is 5-10% of the total mass of the fluorocarbon resin and the epoxy resin.

9. The method for preparing a fluorocarbon coating according to claim 7, characterized in that: The method is as follows: The fluorocarbon resin, xylene and n-butanol are mixed and dissolved, epoxy resin is added dropwise under stirring, and then an auxiliary agent is added, and the temperature is raised to 90° C. to react for 4 hours to obtain the fluorocarbon coating.

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