High-temperature-resistant flame-retardant double-component spraying polyurea coating and preparation method thereof

Abstract

The invention provides a high-temperature-resistant flame-retardant double-component spraying polyurea coating which is prepared from a prepolymer component A and a secondary amine modified chain extender component B. The secondary amine modified chain extender is obtained by reacting hyperbranched polyethyleneimine with carboxylated graphene oxide and ammonium polyphosphate, the modified chain extender has a three-dimensional dendritic structure and amido, the cross-linking density can be improved and the mechanical property can be enhanced by reacting with an isocyanate-containing component, and meanwhile, a rigid structure and a functional group with flame retardance are introduced, so that the polyurea coating has high temperature resistance and flame retardance; the coating has a great application prospect in the aspect of being used as an internal heat insulation spraying polyurea coating.

Description

Technical Field

[0001] The invention belongs to the field of spray-type two-component polyurea coatings, and in particular relates to a high-temperature resistant and flame-retardant two-component spray-type polyurea coating and a preparation method thereof. Background Art

[0002] Polyurea coatings have been widely used in a variety of fields, including anti-corrosion, waterproofing, wear resistance, and protection, due to their excellent mechanical properties, wear resistance, impact resistance, and corrosion resistance. Polyurea coatings also feature high construction efficiency, and the thickness of a single spray application can reach the millimeter level, greatly saving labor costs. Spray polyurea is a coating generated by the rapid reaction of component A (isocyanate component) and component B (amino compound component) in a short period of time. Compared to polyurethane coatings, its tensile strength and weather resistance are superior. In addition, two-component polyurea contains no or small amounts of solvents, is environmentally friendly, and is an important direction for the development of green coatings.

[0003] However, traditional polyurea coatings are generally required to be used at 80°C or below. Excessively high temperatures will cause their mechanical properties and anti-corrosion properties to drop sharply. At the same time, the coating is prone to softening and bubbles. In addition, polyurea itself is extremely flammable, with a limiting oxygen index (LOI) of only about 21%. When burning, it produces a large amount of melt droplets and toxic smoke. A large amount of flaming melt droplets can cause burns to people and rapid spread of fire, and toxic smoke can cause suffocation to people. Therefore, it is of great significance to improve the flame retardant properties of polyurea, inhibit melt droplets and reduce smoke release. Generally speaking, adding flame retardants is the most economical and convenient way to improve the flame retardant properties of polyurea, but this method has problems such as poor compatibility and easy migration and precipitation. These problems will lead to reduced mechanical properties and heat resistance of polyurea coatings.

[0004] Therefore, there is an urgent need to develop a two-component spray polyurea coating with excellent mechanical properties and high temperature resistance and flame retardancy to meet the needs of current social development. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a high-temperature resistant flame-retardant two-component spray polyurea coating, which adopts the reaction of prepolymer component A and secondary amine modified chain extender component B to obtain a high-temperature resistant flame-retardant two-component spray polyurea coating with excellent mechanical properties.

[0006] The above-mentioned object of the present invention is mainly achieved through the following technical solution: a high-temperature resistant flame-retardant two-component spray polyurea coating, which is prepared by mixing component A and component B in a volume ratio of 1:1, wherein the raw material composition and weight ratio of component A are: 50-60 parts of polyether polyol, 40-55 parts of isocyanate, and 0.4-0.6 parts of leveling agent; the raw material composition and weight ratio of component B are: 45-60 parts of difunctional polyether amine, 5-15 parts of trifunctional polyether amine, 10-25 parts of chain extender, 1.5-10 parts of secondary amine modified chain extender, 0.5-1.0 parts of auxiliary agent, and 1.1-2.2 parts of filler, wherein the secondary amine modified chain extender is a hyperbranched polyethyleneimine modified by carboxylated graphene oxide and ammonium polyphosphate, and its structure is shown as follows:

[0007]

[0008] The preparation method of the secondary amine modified chain extender comprises the following steps: dispersing carboxylated graphene oxide in an organic solvent, ultrasonically activating the graphene oxide, adding hyperbranched polyethyleneimine, and after the reaction is completed, filtering under reduced pressure and washing with DMAC and ethanol to obtain an intermediate product; then dispersing the intermediate product in a mixture of ethanol and water, ultrasonically activating the intermediate product, adding ammonium polyphosphate and reacting at 90° C. for 5 hours; washing the product in ethanol, and vacuum drying the product overnight to obtain the secondary amine modified chain extender.

[0009] Furthermore, the mass molar ratio of the carboxylated graphene oxide to polyethyleneimine is 1 g:(15-30) mmol, and the mass ratio of the intermediate product to ammonium polyphosphate is 1:(1.5-3.0).

[0010] Furthermore, the molecular weight of the hyperbranched polyethyleneimine is one or more of 300, 600, 1200, and 1800.

[0011] Furthermore, the polyether polyol of component A is one or more of polyether triol, polypropylene glycol, polytetramethylene ether glycol, and polyoxypropylene glycol with a molecular weight of 1000-2000; the polyisocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate; and the leveling agent is one or more of BYK-333, BYK-348, DC200, and LR-320.

[0012] Furthermore, the difunctional polyetheramine of component B is one or more of D-2001, D-2000, GA2-2000, MA-2200, and MA-2203ED; the trifunctional polyetheramine is one or more of T-403, T-5000, M300, and MA340; and the chain extender is one or more of DETDA, WANALINK4200, E90, DMD230, and E-100.

[0013] Furthermore, the additives of component B include a leveling agent and a defoaming agent, wherein the leveling agent is one or more of BYK-333, BYK-348, DC200, and LR-320; the defoaming agent is one or more of TEGO Foamex 810, BYK-066, Goldschmidt PQ-22, and 6800; and the filler is carbon black, fumed silica, or titanium dioxide.

[0014] Furthermore, the preparation method of the high temperature resistant flame retardant two-component spray polyurea coating comprises the following steps:

[0015] (1) Add polyether polyol to a reaction vessel, heat and stir evenly, remove water in vacuum at 100°C for 2 hours, and then cool to 60°C under argon protection; add polyisocyanate to the reaction vessel, react at 80°C under argon protection for 5 hours, and then cool to 60°C under argon protection; add leveling agent to the reactor, react at 80°C under argon protection for 1 hour, and then cool to 25°C under argon protection, then discharge and seal to obtain component A of the two-component polyurea coating;

[0016] (2) Add polyetheramine, chain extender, and secondary amine modified chain extender into a reaction vessel, heat and stir evenly, remove water in vacuum at 110°C for 2 hours, and then cool to 50°C under argon protection; add auxiliary agents and fillers into the reaction vessel, react at 50°C under argon protection for 1 hour, and then cool to 25°C under argon protection, and then discharge the material into a packaging bottle filled with argon in advance and seal it for storage, thereby obtaining component B of the two-component polyurea coating;

[0017] (3) The component A described in step (1) and the component B described in step (2) are respectively placed in a two-component packaging container at a volume ratio of 1:1 to obtain a high-temperature resistant flame-retardant two-component spray polyurea coating.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention introduces a hyperbranched polyethyleneimine modified amine chain extender into a two-component polyurea coating. The hyperbranched polyethyleneimine has a unique three-dimensional dendritic structure and an amino structure. The modified hyperbranched polyethyleneimine chain extender can react with the isocyanate groups in component A to form a three-dimensional network structure, thereby increasing the crosslinking density of the system and enhancing the mechanical properties of the coating. The tensile strength can reach 23.01 MPa, which is 46.65% higher than that of commercially available polyurea; and the elongation at break can reach 600%, which is 17.50% higher than that of commercially available polyurea.

[0020] 2. The two-component polyurea coating of the present invention uses a hyperbranched polyethyleneimine modified chain extender, utilizes the amino structure to react with carboxylated graphene oxide, connects the graphene oxide to the modifier chain, and then reacts with component A to introduce the rigid structure of graphene oxide into the polyurea coating, which not only makes the polyurea coating high temperature resistance, but also improves the mechanical properties of the polyurea coating.

[0021] 3. The two-component polyurea coating of the present invention utilizes a hyperbranched polyethyleneimine amino structure to react with ammonium polyphosphate to introduce a flame-retardant functional group, and a secondary amine-modified chain extender with a flame-retardant function is added to component B, which not only has good compatibility with the system, but also makes the polyurea coating flame-retardant.

[0022] 4. Compared with conventional polyurea coatings, the two-component polyurea coating of the present invention achieves a suitable dry-to-dry time and application time by adjusting the raw material ratios, thus avoiding the orange peel phenomenon caused by the rapid reaction of conventional polyurea coatings. Furthermore, the raw materials are readily available, the preparation process is simple, and no specialized equipment is required, thus reducing production costs and making it suitable for large-scale production.

[0023] 5. The two-component spray polyurea prepared by the present invention not only makes the polyurea coating flame retardant and high temperature resistant by introducing a secondary amine modified chain extender, but also improves the mechanical properties, and has great application prospects as an internal insulation spray polyurea coating. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0025] Example 1

[0026] Preparation of secondary amine modified chain extender: 3.00 g carboxylated graphene oxide was dispersed in 900 ml DMAC solvent, 9.00 mmol DMAP was added to the dispersed suspension, ultrasonically activated in a water bath for 2 h, and 18.00 g hyperbranched polyethyleneimine (M wThe reaction mixture was stirred for 15 hours at 100°C, cooled to room temperature, filtered under reduced pressure and washed with DMAC and ethanol to obtain an intermediate product, which was then dispersed in a mixture of ethanol and water (volume ratio 20:1), ultrasonically activated for 2 hours, and 27.50 g of ammonium polyphosphate was added and reacted at 90°C for 5 hours. The product was washed with ethanol and vacuum dried overnight to obtain a secondary amine modified chain extender.

[0027] Preparation of component A of high-temperature resistant and flame-retardant two-component spray polyurea coating: Weigh 56.52g of polypropylene glycol (molecular weight is 2000g / mol) and vacuum dehydrate at 100°C for 2h. After cooling to 60°C, add 50.81g of diphenylmethane diisocyanate, react at 80°C for 5h, then cool to 60°C, add 0.42g of leveling agent BYK-333, react at 80°C for 1h, discharge the material and seal it for storage to obtain component 1 of high-temperature resistant and flame-retardant two-component spray polyurea coating A.

[0028] Preparation of component B of high-temperature resistant and flame-retardant two-component spray polyurea coating: Weigh 30.15g of D-2001, 29.20g of D-2000, 8.25g of T-5000, 5.16g of E-100, 4.24g of WANALINK4200 and 4.01g of secondary amine modified chain extender, evacuate at 110°C for 2h, cool to 50°C, add 0.06g of carbon black, 0.42g of silica, 0.09g of titanium dioxide, 0.42g of BYK-333, and 0.15g of defoamer 6800, react at 50°C for 1h, then discharge the material and seal it for storage to obtain component 1 of high-temperature resistant and flame-retardant two-component spray polyurea coating B.

[0029] Components A and B are respectively added into a two-component packaging container at a volume ratio of 1:1 to obtain the high-temperature resistant and flame-retardant two-component spray polyurea coating 1 of the present invention.

[0030] Comparative Example 1

[0031] Preparation of component A of two-component spray polyurea coating: weigh 56.52g of polypropylene glycol (molecular weight 2000g / mol) and vacuum dehydrate at 100℃ for 2h. After cooling to 60℃, add 50.81g of diphenylmethane diisocyanate, react at 80℃ for 5h, then cool to 60℃, add 0.42g of leveling agent BYK-333, react at 80℃ for 1h, discharge the material and seal it for storage, which is component 1 of two-component spray polyurea coating A.

[0032] Preparation of component B of two-component spray polyurea coating: Weigh 30.15g of D-2001, 29.20g of D-2000, 8.25g of T-5000, 12.13g of E-100 and 20.27g of WANALINK4200, evacuate at 110°C for 2h, cool to 50°C, add 0.07g of carbon black, 0.45g of silica, 0.10g of titanium dioxide, 0.45g of BYK-333, and 0.16g of defoamer 6800, react at 50°C for 1h, then discharge the material and seal it for storage, which is component 1 of two-component spray polyurea coating B.

[0033] Components A and B are respectively added into a two-component packaging container in a volume ratio of 1:1 to obtain a two-component spray polyurea coating 1.

[0034] Comparative Example 2

[0035] Preparation of secondary amine modified chain extender: 3.00 g carboxylated graphene oxide was dispersed in 900 ml DMAC solvent, 9.00 mmol DMAP was added to the dispersed suspension, ultrasonically activated in a water bath for 2 h, and 13.50 g hyperbranched polyethyleneimine (M w The reaction mixture was stirred for 15 h at 100 °C, cooled to room temperature, filtered under reduced pressure, washed with DMAC and ethanol, and dried in vacuo overnight to obtain a secondary amine modified chain extender.

[0036] Preparation of component A of two-component spray polyurea coating: Weigh 56.52g of polypropylene glycol (molecular weight is 2000g / mol) and remove water in a vacuum at 100℃ for 2h. After cooling to 60℃, add 50.81g of diphenylmethane diisocyanate, react at 80℃ for 5h, then cool to 60℃, add 0.42g of leveling agent BYK-333, react at 80℃ for 1h, discharge the material and seal it for storage to obtain component 2 of two-component spray polyurea coating A.

[0037] Preparation of component B of two-component spray polyurea coating: Weigh 30.15g of D-2001, 29.20g of D-2000, 8.25g of T-5000, 5.16g of E-100, 4.24g of WANALINK4200 and 4.01g of secondary amine modified chain extender, evacuate at 110°C for 2h, cool to 50°C, add 0.06g of carbon black, 0.42g of silica, 0.09g of titanium dioxide, 0.42g of BYK-333, and 0.15g of defoamer 6800, react at 50°C for 1h, then discharge the material and seal it for storage to obtain component B 2 of two-component spray polyurea coating.

[0038] Components A and B are respectively added into a two-component packaging container in a volume ratio of 1:1 to obtain a two-component spray polyurea coating 2.

[0039] Comparative Example 3

[0040] Preparation of secondary amine modified chain extender: 3.00 g of hyperbranched polyethyleneimine (M w The secondary amine modified chain extender was obtained by adding 3.0 g of ammonium polyphosphate (300 g / mol) to a mixture of ethanol and water (volume ratio 20:1), stirring for 30 min, adding 8.40 g of ammonium polyphosphate, and reacting at 90 ° C for 5 h. The product was washed with ethanol and vacuum dried overnight to obtain a secondary amine modified chain extender.

[0041] Preparation of component A of two-component spray polyurea coating: Weigh 56.52g of polypropylene glycol (molecular weight is 2000g / mol) and remove water in a vacuum at 100℃ for 2h. After cooling to 60℃, add 50.81g of diphenylmethane diisocyanate, react at 80℃ for 5h, then cool to 60℃, add 0.42g of leveling agent BYK-333, react at 80℃ for 1h, discharge the material and seal it for storage to obtain component 3 of two-component spray polyurea coating A.

[0042] Preparation of component B of two-component spray polyurea coating: Weigh 30.15g of D-2001, 29.20g of D-2000, 8.25g of T-5000, 5.16g of E-100, 4.24g of WANALINK4200 and 4.01g of secondary amine modified chain extender, evacuate at 110°C for 2h, cool to 50°C, add 0.06g of carbon black, 0.42g of silica, 0.09g of titanium dioxide, 0.42g of BYK-333, and 0.15g of defoamer 6800, react at 50°C for 1h, then discharge the material and seal it for storage to obtain component 3 of two-component spray polyurea coating B.

[0043] Components A and B are respectively added into a two-component packaging container in a volume ratio of 1:1 to obtain a two-component spray polyurea coating 3.

[0044] Performance testing:

[0045] The tensile strength test and elongation at break test of the corresponding products of Example 1 and Comparative Examples 1-3 were tested in accordance with GB / T 528-2009 on a SansiCMT6000 universal tensile testing machine; the surface dry time was measured using the finger touch method, recording the time from sample mixing to the coating surface becoming non-sticky; the heat resistance test was conducted by placing the sample at 170°C for 7 days and observing the sample phenomena; the flame retardancy test was conducted in accordance with the UL94 test method.

[0046] Table 1: Performance test results of examples and comparative examples

[0047]

[0048] As can be seen from Table 1, compared with Comparative Example 1 which does not contain rigid structure graphene oxide and does not contain flame retardant functional groups, Example 1 does not show brittleness, bulging, falling off and the like under high temperature conditions, and has excellent flame retardancy; compared with Comparative Example 2 which only contains a rigid structure, the flame retardancy is better than Comparative Example 2; compared with Comparative Example 3 which only contains flame retardant functional groups, no brittleness, bulging, or falling off occurs, and the high temperature resistance is good.

[0049] As shown in Table 1, compared with Comparative Examples 1-3, the mechanical properties of Example 1 are better than those of the Comparative Examples.

[0050] In summary, the two-component spray polyurea coating prepared by introducing a secondary amine modified chain extender in the present invention not only has high temperature resistance and flame retardancy, but also has improved mechanical properties.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high temperature resistant flame retardant two-component spray polyurea coating, characterized in that: It is prepared by mixing component A and component B in a volume ratio of 1:1, wherein the raw material composition and weight ratio of component A are: 50-60 parts of polyether polyol, 40-55 parts of isocyanate, and 0.4-0.6 parts of leveling agent; the raw material composition and weight ratio of component B are: 45-60 parts of difunctional polyether amine, 5-15 parts of trifunctional polyether amine, 10-25 parts of chain extender, 1.5-10 parts of secondary amine modified chain extender, 0.5-1.0 parts of auxiliary agent, and 1.1-2.2 parts of filler. The secondary amine modified chain extender is a hyperbranched polyethyleneimine modified by carboxylated graphene oxide and ammonium polyphosphate, and its structure is shown as follows: The preparation method of the secondary amine modified chain extender comprises the following steps: dispersing carboxylated graphene oxide in an organic solvent, ultrasonically activating the graphene oxide, adding hyperbranched polyethyleneimine, and after the reaction is completed, filtering under reduced pressure and washing with DMAC and ethanol to obtain an intermediate product; then dispersing the intermediate product in a mixture of ethanol and water, ultrasonically activating the intermediate product, adding ammonium polyphosphate and reacting at 90° C. for 5 hours; washing the product in ethanol, and vacuum drying the product overnight to obtain the secondary amine modified chain extender.

2. The high temperature resistant flame retardant two-component spray polyurea coating according to claim 1, characterized in that: The mass molar ratio of the carboxylated graphene oxide to polyethyleneimine is 1 g:(15-30) mmol, and the mass ratio of the intermediate product to ammonium polyphosphate is 1:(1.5-3.0).

3. The high temperature resistant flame retardant two-component spray polyurea coating according to claim 1, characterized in that: The molecular weight of the hyperbranched polyethyleneimine is one or more of 300, 600, 1200 and 1800.

4. The high temperature resistant flame retardant two-component spray polyurea coating according to claim 1, characterized in that: The polyether polyol of component A is one or more of polyether triol, polypropylene glycol, polytetramethylene ether glycol, and polyoxypropylene glycol with a molecular weight of 1000-2000; the polyisocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate; and the leveling agent is one or more of BYK-333, BYK-348, DC200, and LR-320.

5. The high temperature resistant flame retardant two-component spray polyurea coating according to claim 1, characterized in that: The difunctional polyetheramine of component B is one or more of D-2001, D-2000, GA2-2000, MA-2200, and MA-2203ED; the trifunctional polyetheramine is one or more of T-403, T-5000, M300, and MA340; and the chain extender is one or more of DETDA, WANALINK4200, E90, DMD230, and E-100.

6. The high temperature resistant flame retardant two-component spray polyurea coating according to claim 1, characterized in that: The additives of component B include a leveling agent and a defoaming agent, wherein the leveling agent is one or more of BYK-333, BYK-348, DC200, and LR-320; the defoaming agent is one or more of TEGO Foamex 810, BYK-066, Goldschmidt PQ-22, and 6800; and the filler is carbon black, fumed silica, or titanium dioxide.

7. The high temperature resistant flame retardant two-component spray polyurea coating according to claims 1-6, characterized in that: The preparation method of the polyurea coating comprises the following steps: (1) Add polyether polyol to a reaction vessel, heat and stir evenly, remove water in vacuum at 100°C for 2 hours, and then cool to 60°C under argon protection; add polyisocyanate to the reaction vessel, react at 80°C under argon protection for 5 hours, and then cool to 60°C under argon protection; add leveling agent to the reactor, react at 80°C under argon protection for 1 hour, and then cool to 25°C under argon protection, then discharge and seal to obtain component A of the two-component polyurea coating; (2) Add polyetheramine, chain extender, and secondary amine modified chain extender to a reaction vessel, heat and stir evenly, remove water in vacuum at 110°C for 2 hours, and then cool to 50°C under argon protection; add additives and fillers to the reaction vessel, react at 50°C under argon protection for 1 hour, and then cool to 25°C under argon protection, and then discharge the material into a packaging bottle filled with argon in advance and seal it for storage, thereby obtaining component B of the two-component polyurea coating; (3) The component A described in step (1) and the component B described in step (2) are respectively placed in a two-component packaging container in a volume ratio of 1:1 to obtain a high-temperature resistant flame-retardant two-component spray polyurea coating.

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