Anti-corrosion intumescent flame-retardant coating and preparation method therefor

Abstract

Disclosed in the present invention are an anti-corrosion intumescent flame-retardant coating and a preparation method therefor, belonging to the technical field of coatings. By means of introduction of an independently researched and developed phosphite curing agent into a specific epoxy-furan-amino resin system, the product of the present invention can effectively achieve high flame retardance and intumescence ratio, and has good long-acting corrosion-resistant property and excellent comprehensive effects.

Description

Anti-corrosion intumescent flame retardant coating and preparation method thereof Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to an anti-corrosion intumescent flame-retardant coating and a preparation method thereof. Background Art

[0002] In the construction industry, steel structural materials need to be specially protected with coatings because they are extremely susceptible to corrosion from water and oxygen. At the same time, this metal material has extremely strong thermal conductivity. If it is instantly heated and a fire occurs, it will quickly lose its bearing capacity in a short period of time, which may lead to serious consequences such as building collapse.

[0003] To this end, people will develop some coatings with high anti-corrosion and / or high flame retardant functions to coat and protect steel structural materials. However, these coatings have little expansion effect after exposure to fire and have a low residual carbon rate. Once the fire is large, they cannot effectively extend the supporting time of the steel structural materials and increase the evacuation and escape rate of people in the building. At the same time, this type of product often needs to be re-coated. The main reason is that its anti-corrosion function is short-lived and will become ineffective after a certain number of years of use, requiring re-coating with new materials.

[0004] Summary of the Invention

[0005] Based on the defects of the existing technology, the purpose of the present invention is to provide an anti-corrosion intumescent flame-retardant coating. By introducing an independently developed phosphite curing agent into a specific epoxy-furan-amino resin system, it can not only effectively achieve high flame retardancy and expansion ratio, but also have good long-term anti-corrosion properties and excellent comprehensive effects.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] An anti-corrosion intumescent flame-retardant coating comprising the following components in parts by weight:

[0008] 30-50 parts of epoxy resin, 5-30 parts of furan resin, 5-25 parts of amino resin, 10-80 parts of flame retardant, 10-30 parts of curing agent, and 30-50 parts of diaminodiphenylmethane-phosphorus-containing polyol-phosphite.

[0009] In order to achieve high flame retardancy and long-term corrosion resistance, the anti-corrosion intumescent flame retardant coating of the present invention adopts a compound of epoxy resin, furan resin and amino resin as the base resin, wherein the furan resin itself has good corrosion resistance, but the resin is relatively brittle and has almost no thermal expansion. The amino resin will produce gas after being exposed to fire, thereby increasing the expansion ratio of the product, but it itself cannot be effectively matched with the composite resin for cross-linking at room temperature, so the adhesion and corrosion resistance to the coated object are not strong. For this reason, the inventors additionally introduced diaminodiphenylmethane-phosphorus-containing polyol-phosphite as a flame retardant and corrosion resistance synergistic curing agent, which not only allows the base resin to be cured at room temperature and improves adhesion, but also the benzene ring structure it contains can cooperate with the amino resin to improve the flame retardancy of the product, further improve the expansion ratio, and have a high charring rate, so that the product can have both good flame retardancy and long-term corrosion resistance. However, the introduction of this component requires the three base resins to be compounded in a specific ratio to achieve the desired effect. Once the compounding ratio is inappropriate, the introduction of diaminodiphenylmethane-phosphorus-containing polyol-phosphite may have a negative impact.

[0010] Preferably, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin.

[0011] 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.

[0012] Preferably, the mass ratio of the epoxy resin to the furan resin is (50:10) to (30:30).

[0013] More preferably, the mass ratio of the epoxy resin to the furan resin is (45:15) to (35:25).

[0014] Since furan resin has a certain influence on the anti-corrosion and flame retardant properties of the product, it is preferred that when the mass ratio of the epoxy resin body to the compounded furan resin is maintained within the above preferred range, the comprehensive performance of the product is better.

[0015] Preferably, the amino resin is a Cymel series resin produced by Cytec of the United States.

[0016] More preferably, the amino resin is at least one of Cymel 325, Cymel 324, Cymel 345, Cymel 385, Cymel 303 LF, Cymel 308, Cymel 327, Cymel 659, Cymel 323, and Cymel 328.

[0017] Preferably, the weight proportion of the amino resin is 8 to 12 parts.

[0018] The added content of amino resin will affect the strength, adhesion and flame retardancy of the product. Therefore, when selecting the above-mentioned parts by weight, the product can take into account the strength, adhesion and flame retardancy of the product at the same time.

[0019] Preferably, the flame retardant is at least one of a phosphorus-based flame retardant and a nitrogen-based flame retardant.

[0020] More preferably, the phosphorus-based flame retardant is at least one of ammonium polyphosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, and hexaphenoxycyclotriphosphazene.

[0021] More preferably, the nitrogen-based flame retardant is at least one of melamine cyanurate, melamine, and melamine polyphosphate.

[0022] Preferably, the curing agent is a polyamide curing agent.

[0023] The polyamide curing agent can cooperate with the diaminodiphenylmethane-phosphorus-containing polyol-phosphite of the present invention to achieve good flame retardancy and expansion performance of the product.

[0024] Preferably, the preparation method of the diaminodiphenylmethane-phosphorus-containing polyol-phosphite comprises the following steps:

[0025] Diaminodiphenylmethane and phosphorus-containing polyol are mixed, and then heated and stirred at 120-150° C. for 1.5-2.5 hours. 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 the mixture is heated and stirred at 80-100° C. for 7.5-9.5 hours. The mixture is rotary evaporated and dried to obtain the diaminodiphenylmethane-phosphorus-containing polyol-phosphite.

[0026] It should be noted that the preparation method of diaminodiphenylmethane-phosphorus-containing polyol-phosphite described in the present invention is not limited to the above-mentioned forms or steps. Those skilled in the art can adopt other forms or steps to prepare products with similar or identical properties according to actual needs, as long as similar technical effects are achieved.

[0027] Preferably, the phosphorus-containing polyol is at least one of an alcohol-containing phosphorus-containing compound and a polyol phosphate.

[0028] More preferably, the alcohol-containing phosphorus-containing compound is the phosphorus-containing compound OP 550 produced by Clariant.

[0029] More preferably, the polyol phosphate is glycerol phosphate.

[0030] Preferably, the phosphite is at least one of diphenyl phosphite, dimethyl phosphite, diethyl phosphite, and dibutyl phosphite.

[0031] 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).

[0032] Preferably, the components of the anti-corrosion intumescent flame-retardant coating include 0.5 to 5 parts of a silane coupling agent and 0 to 3 parts of a processing aid.

[0033] More preferably, the silane coupling agent is at least one of KH550 and KH560.

[0034] More preferably, the processing aid includes at least one of a defoaming agent and an anti-settling agent.

[0035] Another object of the present invention is to provide a method for preparing the anti-corrosion intumescent flame retardant coating, comprising the following steps:

[0036] The epoxy resin and the furan resin are mixed, and then the amino resin, the flame retardant, the silane coupling agent, the flame retardant curing agent and the curing agent are added in sequence and mixed until uniform, thereby obtaining the anti-corrosion intumescent flame retardant coating.

[0037] The preparation method of the anti-corrosion intumescent flame-retardant coating of the present invention has simple steps, does not require special equipment for implementation, and can realize industrial-scale production.

[0038] Another object of the present invention is to provide an application of the anti-corrosion intumescent flame retardant coating in the preparation of building components.

[0039] Steel structure building components in the construction field need to be coated with special effect coatings on the surface to improve their performance. The product described in the present invention can give building components corrosion resistance and acid and alkali resistance after coating, thereby extending their service life. At the same time, the flame retardant components and expansion components contained in it can expand rapidly when exposed to heat and isolate the heat source, thereby buying more escape time for escaping personnel, and it is highly practical.

[0040] The beneficial effect of the present invention is that the present invention provides an anti-corrosion intumescent flame-retardant coating, which, by introducing an independently developed phosphite curing agent into a specific epoxy-furan-amino resin system, can not only effectively achieve high flame retardancy and expansion ratio, but also have good long-term anti-corrosion properties and excellent comprehensive effects. DETAILED DESCRIPTION

[0041] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples. Its purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all commonly used ordinary reagents and instruments unless otherwise specified.

[0042] In the present invention, the bisphenol A epoxy resin is an E51 epoxy resin produced by Sinopec Baling Petrochemical Co., Ltd.

[0043] The bisphenol F epoxy resin is NPEF-500 produced by Nanya Epoxy Resin Co., Ltd.

[0044] The furan resin was GM-1 furfuryl alcohol furan resin produced by Wuxi Xinyehao Chemical Co., Ltd.

[0045] The amino resins are 303LF and 385 resins produced by Cymel.

[0046] Examples 1 to 14

[0047] An embodiment of the anti-corrosion intumescent flame-retardant coating and a preparation method thereof according to the present invention, the components of the anti-corrosion intumescent flame-retardant coating are shown in Table 1.

[0048] The preparation method of the anti-corrosion intumescent flame-retardant coating comprises the following steps:

[0049] At room temperature and pressure, epoxy resin and furan resin are mixed at 600 r / min for 10 minutes, then amino resin is added and mixed at 700 r / min for 10 minutes, and finally flame retardant, silane coupling agent, flame retardant curing agent and curing agent are added in sequence and continued to mix at 1100 r / min for 30 minutes until uniform, thereby obtaining the anti-corrosion intumescent flame retardant coating.

[0050] The preparation method of the diaminodiphenylmethane-phosphorus-containing polyol-phosphite 1 comprises the following steps:

[0051] Diaminodiphenylmethane and phosphorus-containing polyol are mixed, and then heated and stirred at 130° C. for 2 hours. Excess carbon tetrachloride is added to the resulting liquid phase, and the pH is adjusted to 7.1-7.5. Phosphite is added, mixed, and heated and stirred at 90° C. for 8 hours. The carbon tetrachloride is removed by rotary evaporation to obtain the diaminodiphenylmethane-phosphorus-containing polyol-phosphite.

[0052] The phosphorus-containing polyol is OP 550 produced by Clariant, and the phosphite is diethyl phosphite.

[0053] The molar ratio of the diaminodiphenylmethane, phosphorus-containing polyol and phosphite is 1:1:1.

[0054] The only difference between the diaminodiphenylmethane-phosphorus-containing polyol-phosphite 2 and the diaminodiphenylmethane-phosphorus-containing polyol-phosphite 1 is that the phosphite is a mixture of dibutyl phosphite and diethyl phosphite in a molar ratio of 1:1.

[0055] Comparative Examples 1 to 12

[0056] The difference between the comparative examples and the examples is only in the types and proportions of the components, as shown in Table 2.

[0057] Unless otherwise specified, the components and raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0058] Table 1

[0059] Table 2

[0060] In order to verify the performance of the products of the present invention, the products prepared in each embodiment and comparative example were subjected to the following performance tests. The specific steps are as follows:

[0061] (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 smooth.

[0062] (2) Adhesion test: refer to GB / T 9286-2021;

[0063] (3) Moisture and heat resistance test: refer to GB / T 1740-89;

[0064] (4) Salt spray resistance test: refer to GB / T 1771-2007;

[0065] (5) Flame retardant grade test: refer to ANSI / UL-94-1985;

[0066] (6) Expansion ratio 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 24 hours, they were sprayed with a 1200°C high-temperature spray gun to completely burn them. The expansion thickness was measured and the expansion ratio was confirmed.

[0067] The test results are shown in Tables 3 and 4.

[0068] Table 3

[0069] Table 4

[0070] As can be seen from Tables 3 and 4, the products of the present invention have ideal comprehensive performance. They not only have a good appearance, but also have strong adhesion, good resistance to moisture and heat and salt spray, and a high flame retardant grade. Most importantly, the combustion expansion ratio of the products reaches more than 35 times. In the event of a fire, the coating can effectively expand and isolate the fire source, giving people enough time to escape.

[0071] It can be seen from Examples 3 and 4 to 7 that the performance of the products varies depending on the content ratio of furan resin to epoxy resin. When the furan resin content is too high, the expansion ratio of the product will decrease, and 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).

[0072] It can be seen from Examples 3 and 8 to 10 that different types of amino resins have little effect on the performance of the product. However, since amino resins not only affect the adhesion of the product but also affect the combustion expansion ratio of the product, the best effect is achieved when added in a moderate content.

[0073] It can be seen from Example 3 and Examples 11 to 13 that the type, quantity and added content of the flame retardant in the product have little effect on the expansion ratio of the product. Although the introduction of more nitrogen-containing flame retardant components can increase the expansion ratio of the product, the degree of improvement is very limited. Excessive introduction is not conducive to the control of product production.

[0074] In contrast, the amino resin in the product of Comparative Example 1 is as high as 30 parts. As mentioned above, although the expansion ratio of the product is higher, the adhesion and moisture and heat resistance of the product are relatively unsatisfactory and cannot be effectively used in practice.

[0075] The added content of diaminodiphenylmethane-phosphorus-containing polyol-phosphite in the product of Comparative Example 2 is too low, and the expansion ratio of the product is extremely low, only 20 times. In the products of Comparative Examples 3 and 4, although the total amount of curing agent is the same, the polyamide curing agent is not paired with diaminodiphenylmethane-phosphorus-containing polyol-phosphite, but with conventional T31 and 593 curing agents. Neither of these two curing agents can increase the expansion ratio of the product. The main reason is that these two curing agents will make the product extremely hard and unable to expand when carbonized by heat. In the product of Comparative Example 5, although pure 650 curing agent can cause the product to expand to a certain extent, the expansion ratio is low and cannot reach the level of the example products.

[0076] The unbalanced ratio of epoxy resin to furan resin in the product of Comparative Example 6 results in an expansion ratio of only 30 times. This fully demonstrates that a high expansion ratio cannot be achieved simply by introducing a coating system containing diaminodiphenylmethane-phosphorus-containing polyol-phosphite as a synergistic component. It is also necessary to consider a suitable matrix resin formula.

[0077] 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 the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An anti-corrosion intumescent flame retardant coating, characterized in that: The composition comprises the following components in parts by weight: 30-50 parts of epoxy resin, 5-30 parts of furan resin, 5-25 parts of amino resin, 10-80 parts of flame retardant, 10-30 parts of curing agent, and 30-50 parts of diaminodiphenylmethane-phosphorus-containing polyol-phosphite.

2. The anti-corrosion intumescent flame retardant coating according to claim 1, characterized in that: The epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin, and / or 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.

3. The anti-corrosion intumescent flame retardant coating according to claim 1, characterized in that: The mass ratio of the epoxy resin to the furan resin is (50:10) to (30:30); preferably, the mass ratio of the epoxy resin to the furan resin is (45:15) to (35:25).

4. The anti-corrosion intumescent flame retardant coating according to claim 1, characterized in that: The weight proportion of the amino resin is 8 to 12 parts.

5. The anti-corrosion intumescent flame retardant coating according to claim 1, characterized in that: The flame retardant is at least one of a phosphorus-based flame retardant and a nitrogen-based flame retardant.

6. The anti-corrosion intumescent flame retardant coating according to claim 5, characterized in that: The phosphorus-based flame retardant is at least one of ammonium polyphosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, and hexaphenoxy cyclotriphosphazene, and / or the nitrogen-based flame retardant is at least one of melamine cyanurate, melamine, and melamine polyphosphate.

7. The anti-corrosion intumescent flame retardant coating according to claim 1, characterized in that: The curing agent is a polyamide curing agent.

8. The anti-corrosion intumescent flame retardant coating according to claim 1, characterized in that: The components of the anti-corrosion intumescent flame-retardant coating include 0.5 to 5 parts of a silane coupling agent and 0 to 3 parts of a processing aid.

9. The method for preparing the anti-corrosion intumescent flame-retardant coating according to claim 8, characterized in that: The following steps are involved: The epoxy resin and the furan resin are mixed, and then the amino resin, the flame retardant, the silane coupling agent, the flame retardant curing agent and the curing agent are added in sequence and mixed until uniform, thereby obtaining the anti-corrosion intumescent flame retardant coating.

10. Use of the anti-corrosion intumescent flame retardant coating according to any one of claims 1 to 8 in the preparation of building components.

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