Anticorrosive intumescent fire-retardant coating and preparation method thereof

Abstract

This invention discloses an anti-corrosion intumescent flame-retardant coating and its preparation method, belonging to the field of coating technology. The product of this invention introduces a self-developed phosphite-based curing agent into a specific epoxy-furan-amino resin system, which can not only effectively achieve high flame retardancy and expansion ratio, but also has good long-lasting anti-corrosion performance and excellent overall effect.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an anti-corrosion, intumescent flame-retardant coating and its preparation method. Background Technology

[0002] In the construction industry, steel structure materials require special protective treatment with coatings because they are extremely susceptible to water and oxygen corrosion. At the same time, this metal material has extremely high thermal conductivity. If it is heated instantly and a fire occurs, it will quickly lose its load-bearing capacity, which may lead to serious consequences such as building collapse.

[0003] Therefore, people develop coatings with high anti-corrosion and / or high flame-retardant properties for the protection of steel structure materials. However, these coatings do not expand significantly when exposed to fire and have a low carbon residue rate. Once the fire is large, they cannot effectively extend the support time of the steel structure materials and improve the evacuation and escape rate of people inside the building. At the same time, these products often need to be recoated, mainly because their anti-corrosion function is short-lived and will fail after a certain number of years of use, requiring a fresh coat. Summary of the Invention

[0004] Based on the shortcomings of existing technologies, the purpose of this invention is to provide a corrosion-resistant, intumescent flame-retardant coating. By introducing a self-developed phosphite-based curing agent into a specific epoxy-furan-amino resin system, it can not only effectively achieve high flame retardancy and expansion ratio, but also has good long-lasting corrosion resistance and excellent overall performance.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An anti-corrosion, intumescent flame-retardant coating comprises the following components in parts by weight:

[0007] 30-50 parts epoxy resin, 5-30 parts furan resin, 5-25 parts amino resin, 10-80 parts flame retardant, 10-30 parts curing agent, and 30-50 parts diaminodiphenylmethane-phosphorus polyol-phosphite.

[0008] To achieve high flame retardancy, expansion, and long-lasting corrosion resistance, the corrosion-resistant and expansion-type flame retardant coating of this invention uses epoxy resin, furan resin, and amino resin as the base resin. While furan resin itself has good corrosion resistance, it is brittle and has almost no thermal expansion. Amino resin, on the other hand, produces gas upon exposure to fire, thus increasing the product's expansion ratio. However, it cannot effectively cross-link with the composite resin at room temperature, resulting in weak adhesion and corrosion resistance. Therefore, the inventors additionally introduced diaminodiphenylmethane-phosphorus-containing polyol-phosphite as a synergistic curing agent for flame retardancy and corrosion resistance. This not only allows the base resin to cure at room temperature and improves adhesion, but its benzene ring structure also synergistically enhances the flame retardancy of the product, further increasing the expansion ratio and resulting in a high char formation rate. Thus, the product achieves both good flame retardancy and long-lasting corrosion resistance. However, the introduction of this component requires the three matrix resins to be compounded in a specific ratio to achieve the desired effect. If the compounding ratio is not appropriate, the introduction of diaminodiphenylmethane-phosphorus polyol-phosphite may have a negative impact.

[0009] Preferably, the epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin.

[0010] Preferably, the furan resin is at least one of urea-formaldehyde furan resin, phenol-urea-formaldehyde furan resin, formaldehyde-furfuryl alcohol resin, and high-furfuryl alcohol resin.

[0011] Preferably, the mass ratio of the epoxy resin to the furan resin is (50:10) to (30:30).

[0012] More preferably, the mass ratio of the epoxy resin to the furan resin is (45:15) to (35:25).

[0013] Since furan resin has a certain impact on the anti-corrosion and flame retardant properties of the product, after optimization, when the mass ratio of epoxy resin to compounded furan resin is maintained within the above-mentioned preferred range, the overall performance of the product is better.

[0014] Preferably, the amino resin is a Cymel series resin manufactured by Cytec Corporation of the United States.

[0015] More preferably, the amino resin is at least one of Cymel 325, Cymel 324, Cymel 345, Cymel 385, Cymel 303LF, Cymel 308, Cymel 327, Cymel 659, Cymel 323, and Cymel 328.

[0016] Preferably, the amino resin is present in 8 to 12 parts by weight.

[0017] The amount of amino resin added will affect the product's strength, adhesion and flame retardancy. Therefore, when selecting the above weight percentage, the product can simultaneously take into account the product's strength, adhesion and flame retardancy.

[0018] Preferably, the flame retardant is at least one of phosphorus-based flame retardants and nitrogen-based flame retardants.

[0019] More preferably, the phosphorus-based flame retardant is at least one of ammonium polyphosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, and hexaphenoxycyclotriphosphazene.

[0020] More preferably, the nitrogen-based flame retardant is at least one of melamine cyanurate, melamine, and melamine polyphosphate.

[0021] Preferably, the curing agent is a polyamide curing agent.

[0022] Polyamide curing agents can work synergistically with the diaminodiphenylmethane-phosphorus polyol-phosphite described in this invention to achieve good flame retardant and expansion properties of the product.

[0023] Preferably, the preparation method of the diaminodiphenylmethane-phosphorus polyol-phosphite includes the following steps:

[0024] Diaminodiphenylmethane and phosphorus-containing polyol are mixed, and then heated and stirred at 120-150°C for 1.5-2.5 h. Carbon tetrachloride is added to the resulting liquid phase and the pH is adjusted to 7.1-7.5. Phosphite is added and mixed, and then heated and stirred at 80-100°C for 7.5-9.5 h. The mixture is then dried by rotary evaporation to obtain the diaminodiphenylmethane-phosphorus-containing polyol-phosphite.

[0025] It should be noted that the preparation method of diaminodiphenylmethane-phosphorus polyol-phosphite described in this invention is not limited to the above-mentioned form or steps. Those skilled in the art can use other forms or steps to prepare products with similar or identical properties according to actual needs, and are not limited as long as similar technical effects are achieved.

[0026] Preferably, the phosphorus-containing polyol is at least one of an alcohol-containing phosphorus-containing compound or a polyol phosphate ester.

[0027] More preferably, the phosphorus-containing compound containing an alcohol group is OP 550, a phosphorus-containing compound produced by Clariant.

[0028] More preferably, the polyol phosphate ester is a glycerol phosphate ester.

[0029] Preferably, the phosphite is at least one selected from diphenyl phosphite, dimethyl phosphite, diethyl phosphite, and dibutyl phosphite.

[0030] More preferably, the molar ratio of the diaminodiphenylmethane, the phosphorus-containing polyol, and the phosphite is at least one of (0.8-1.2):(0.8-1.2):(0.8-1.2).

[0031] Preferably, the components of the anti-corrosion intumescent flame-retardant coating include 0.5 to 5 parts of silane coupling agent and 0 to 3 parts of processing aid.

[0032] More preferably, the silane coupling agent is at least one of KH550 and KH560.

[0033] More preferably, the processing aid includes at least one of defoamer and anti-settling agent.

[0034] Another object of the present invention is to provide a method for preparing the aforementioned anti-corrosion intumescent flame-retardant coating, comprising the following steps:

[0035] Epoxy resin and furan resin are mixed, and then amino resin, flame retardant, silane coupling agent, flame retardant curing agent and curing agent are added in sequence and mixed until uniform to obtain the anti-corrosion intumescent flame retardant coating.

[0036] The preparation method of the anti-corrosion intumescent flame-retardant coating of the present invention is simple, requires no special equipment, and can achieve industrial-scale production.

[0037] Another object of the present invention is to provide the application of the aforementioned anti-corrosion intumescent flame-retardant coating in the preparation of building components.

[0038] In the construction industry, steel structure building components need to be coated with special effect coatings to improve their performance. The product described in this invention can give building components corrosion resistance and acid and alkali resistance after coating, extending their service life. At the same time, the flame retardant and expansion components it contains can expand rapidly when heated and insulate the heat source, giving escapers more time to escape. It is highly practical.

[0039] The beneficial effects of this invention are that it provides a corrosion-resistant, intumescent flame-retardant coating. By introducing a self-developed phosphite-based curing agent into a specific epoxy-furan-amino resin system, it can not only effectively achieve high flame retardancy and expansion ratio, but also has good long-lasting corrosion resistance and excellent overall performance. Detailed Implementation

[0040] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0041] In this invention, the bisphenol A type epoxy resin is E51 type epoxy resin produced by Sinopec Baling Petrochemical Co., Ltd.

[0042] Bisphenol F epoxy resin is NPEF-500 type epoxy resin manufactured by Nan Ya Epoxy Resin Co., Ltd.

[0043] The furan resin is GM-1 furfuryl furan resin produced by Wuxi Xinyehao Chemical Co., Ltd.

[0044] The amino resins are Cymel's 303LF and 385 types.

[0045] Examples 1-14

[0046] An embodiment of the anti-corrosion intumescent flame-retardant coating and its preparation method described in this invention is shown in Table 1.

[0047] The preparation method of the corrosion-resistant, intumescent flame-retardant coating includes the following steps:

[0048] At room temperature and pressure, epoxy resin and furan resin are mixed at 600 r / min for 10 min, followed by the addition of amino resin and mixing at 700 r / min for 10 min. Finally, flame retardant, silane coupling agent, flame retardant curing agent and curing agent are added in sequence and mixed at 1100 r / min for 30 min until uniform, thus obtaining the corrosion-resistant and intumescent flame retardant coating.

[0049] The preparation method of the diaminodiphenylmethane-phosphorus polyol-phosphite 1 includes the following steps:

[0050] Diaminodiphenylmethane and phosphorus-containing polyol were mixed, and then heated and stirred at 130°C for 2 hours. Excess carbon tetrachloride was added to the resulting liquid phase to adjust the pH to 7.1-7.5. Phosphite was added and mixed, and the mixture was heated and stirred at 90°C for 8 hours. Carbon tetrachloride was removed by rotary evaporation to obtain the diaminodiphenylmethane-phosphorus-containing polyol-phosphite.

[0051] The phosphorus-containing polyol is Clariant's OP 550, and the phosphite is diethyl phosphite.

[0052] The molar ratio of diaminodiphenylmethane, phosphorus-containing polyol, and phosphite is 1:1:1.

[0053] The difference between the diaminodiphenylmethane-phosphorus polyol-phosphite ester 2 and the diaminodiphenylmethane-phosphorus polyol-phosphite ester 1 is that the phosphite ester is a mixture of dibutyl phosphite and diethyl phosphite in a molar ratio of 1:1.

[0054] Comparative Examples 1-12

[0055] The only difference between each comparative example and the embodiment is the type and ratio of components, as shown in Table 2.

[0056] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0057] Table 1

[0058]

[0059] Table 2

[0060]

[0061]

[0062] To verify the performance of the product described in this invention, the products prepared in each embodiment and comparative example were subjected to the following performance tests, the specific steps of which are as follows:

[0063] (1) Appearance test: The products of each embodiment and comparative example were coated on a steel plate with a coating thickness of 500 μm. After standing at room temperature and normal pressure for 72 hours, the surface was visually inspected to see if it was flat.

[0064] (2) Adhesion test: Conducted in accordance with GB / T 9286-2021;

[0065] (3) Damp heat resistance test: Refer to GB / T 1740-89;

[0066] (4) Salt spray resistance test: Conducted in accordance with GB / T 1771-2007;

[0067] (5) Flame retardancy rating test: Refer to ANSI / UL-94-1985;

[0068] (6) Expansion ratio test: The products of each example and comparative example were coated on a steel plate with a coating thickness of 500 μm. After standing at room temperature and normal pressure for 24 hours, they were sprayed with a high-temperature spray gun at 1200℃ and burned completely. The expansion thickness was measured and the expansion thickness ratio was confirmed.

[0069] The test results are shown in Tables 3 and 4.

[0070] Table 3

[0071]

[0072]

[0073] Table 4

[0074]

[0075] As can be seen from Tables 3 and 4, the product described in this invention has ideal comprehensive performance. It not only has a good appearance, but also strong adhesion, good resistance to damp heat and salt spray, and a high flame retardant rating. Most importantly, the product's combustion expansion ratio reaches more than 35 times. In the event of a fire, the coating can effectively expand and isolate the fire source, giving escapers ample time to escape.

[0076] As can be seen from Examples 3 and 4-7, the different proportions of furan resin and epoxy resin result in different performance characteristics of the product. When the furan resin content is too high, the expansion ratio of the product will decrease, while when the epoxy resin content is too high, the salt spray resistance of the product will decrease to a certain extent. Therefore, the mass ratio of the two is better when it is in the range of (45:15) to (35:25).

[0077] As can be seen from Examples 3 and 8-10, different types of amino resins have little effect on the performance of the product. However, since amino resins affect not only the adhesion of the product but also the combustion expansion ratio of the product, adding an appropriate amount will have the best effect.

[0078] As can be seen from Examples 3 and 11-13, the type, quantity, and content of flame retardants in the product have little effect on the product's expansion ratio. Although introducing more nitrogen-containing flame retardant components can increase the product's expansion ratio, the increase is very limited, and excessive introduction is actually detrimental to product control and finished product production.

[0079] In contrast, the product in Comparative Example 1 contains as much as 30 parts of amino resin. As mentioned above, although the product has a higher expansion ratio, its adhesion and resistance to damp heat are not ideal, making it unsuitable for practical application.

[0080] In Comparative Example 2, the content of diaminodiphenylmethane-phosphorus polyol-phosphite was too low, resulting in an extremely low expansion ratio of only 20 times. While Comparative Examples 3 and 4 had the same total amount of curing agent, the curing agents used were not diaminodiphenylmethane-phosphorus polyol-phosphite, but rather conventional T31 and 593 curing agents. Neither of these curing agents could increase the expansion ratio, primarily because they resulted in extremely high hardness, preventing expansion during heat carbonization. In Comparative Example 5, although pure 650 curing agent could induce some expansion, the expansion ratio was low and could not reach the level of the products in the examples.

[0081] The imbalance between epoxy resin and furan resin in Comparative Example 6 resulted in an expansion ratio of only 30 times, which fully demonstrates that simply introducing diaminodiphenylmethane-phosphorus polyol-phosphite as a synergistic component into a coating system does not necessarily guarantee a high expansion ratio. It is also necessary to focus on the appropriate matrix resin formulation.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A corrosion-resistant, intumescent flame-retardant coating, characterized in that, The components include the following parts by weight: 30-50 parts epoxy resin, 5-30 parts furan resin, 5-25 parts amino resin, 10-80 parts flame retardant, 10-30 parts curing agent, and 30-50 parts diaminodiphenylmethane-phosphorus polyol-phosphite. The preparation method of the diaminodiphenylmethane-phosphorus polyol-phosphite includes the following steps: Diaminodiphenylmethane and phosphorus-containing polyol are mixed, and then heated and stirred at 120~150℃ for 1.5~2.5h. Carbon tetrachloride is added to the resulting liquid phase and the pH is adjusted to 7.1~7.

5. Phosphite is added and mixed, and then heated and stirred at 80~100℃ for 7.5~9.5h. The mixture is then dried by rotary evaporation to obtain the diaminodiphenylmethane-phosphorus-containing polyol-phosphite. The phosphorus-containing polyol is at least one of the phosphorus-containing compound OP 550 and polyol phosphate ester; the polyol phosphate ester is a glycerol phosphate ester. The molar ratio of diaminodiphenylmethane, phosphorus-containing polyol, and phosphite is (0.8~1.2):(0.8~1.2):(0.8~1.2).

2. The anti-corrosion intumescent flame-retardant coating as described in claim 1, characterized in that, The epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin, and / or the furan resin is at least one of urea-formaldehyde furan resin, formaldehyde-furfuryl alcohol resin, and high-furfuryl alcohol resin.

3. The anti-corrosion intumescent flame-retardant coating as described in claim 1, characterized in that, The mass ratio of epoxy resin to furan resin is (50:10) to (30:30).

4. The anti-corrosion intumescent flame-retardant coating as described in claim 3, characterized in that, The mass ratio of epoxy resin to furan resin is (45:15) to (35:25).

5. The anti-corrosion intumescent flame-retardant coating as described in claim 1, characterized in that, The amino resin is present in 8 to 12 parts by weight.

6. The anti-corrosion intumescent flame-retardant coating as described in claim 1, characterized in that, The flame retardant is at least one of phosphorus-based flame retardants and nitrogen-based flame retardants.

7. The anti-corrosion intumescent flame-retardant coating as described in claim 6, characterized in that, The phosphorus-based flame retardant is at least one of ammonium polyphosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, and hexaphenoxycyclotriphosphazene, and / or the nitrogen-based flame retardant is at least one of melamine cyanurate, melamine, and melamine polyphosphate.

8. The anti-corrosion intumescent flame-retardant coating as described in claim 1, characterized in that, The curing agent is a polyamide curing agent.

9. The anti-corrosion intumescent flame-retardant coating as described in claim 1, characterized in that, The components of the corrosion-resistant, intumescent flame-retardant coating include 0.5 to 5 parts of silane coupling agent and 0 to 3 parts of processing aid.

10. The preparation method of the anti-corrosion intumescent flame-retardant coating as described in claim 9, characterized in that, Includes the following steps: Epoxy resin and furan resin are mixed, and then amino resin, flame retardant, silane coupling agent, diaminodiphenylmethane-phosphorus polyol-phosphite and curing agent are added in sequence and mixed until uniform to obtain the anti-corrosion intumescent flame retardant coating.

11. The application of the anti-corrosion intumescent flame-retardant coating as described in any one of claims 1 to 9 in the preparation of building components.

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