Light-cured flame-retardant coating added with anacardol and preparation method thereof

Abstract

The invention discloses a preparation method of a light-cured flame-retardant coating added with anacardol. The preparation method specifically comprises the following steps: step 1, synthesizing a polyurethane acrylic resin monomer containing anacardol; and 2, curing the product obtained in the step 1. The invention also discloses a light-cured flame-retardant coating added with cardanol, the flame-retardant coating prepared by the invention can be used for increasing the pyrolysis temperature of the flame-retardant coating while reducing the addition amount of the flame retardant, and meanwhile, the pollution to the environment is reduced.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant materials technology, and relates to a light-cured flame retardant coating with added cashew nut shell powder. This invention also relates to a method for preparing a light-cured flame retardant coating with added cashew nut shell powder. Background Technology

[0002] Organic polymer materials are highly flammable due to their carbon and oxygen-based skeletons. Therefore, developing flame-retardant polymers can reduce fire hazards and prevent loss of life and property. Currently, there are two main methods to improve the flame retardancy of polymers: doping with flame retardants and adding flame-retardant groups to the polymer structure. However, blended flame retardants suffer from reagent precipitation, leading to poor manufacturability and mechanical properties. In contrast, reactive flame retardants offer advantages such as high flame-retardant efficiency, enhanced adhesion to polymer substrates, and improved solubility, making them more promising for applications.

[0003] While adding halogenated flame retardants can give polymers excellent flame retardancy, they release dioxins and furans during the flame retardation process, causing environmental pollution and increasing the risk of cancer in humans. Common UV-cured flame retardant coatings contain 60-90% flame retardant additives, but their main pyrolysis temperature is only 280-300℃. How to minimize the amount of flame retardant added while increasing the pyrolysis temperature of the flame retardant coating is a problem that needs to be solved in the future. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a light-cured flame-retardant coating with added cashew phenol. The flame-retardant coating prepared by this method can increase the pyrolysis temperature of the flame-retardant coating while reducing the amount of flame retardant added, and at the same time reduce environmental pollution.

[0005] Another object of the present invention is to provide a light-cured flame-retardant coating with added cashew phenol.

[0006] The first technical solution adopted in this invention is a method for preparing a photocurable flame-retardant coating with added cashew phenol, specifically including the following steps: Step 1: Synthesize polyurethane acrylic resin monomers containing cashew phenol; Step 2: Curing the product obtained in Step 1.

[0007] The first technical solution of this invention is further characterized by: The specific process of step 1 is as follows: Under nitrogen atmosphere, di(2-(methacryloyloxy)ethyl) phosphate, cashew phenol, 4,4'-dicyclohexylmethane diisocyanate and ethyl acetate are poured into a flask and stirred. After stirring, the ethyl acetate is removed by rotary evaporation to obtain the polyurethane acrylic resin monomer containing cashew phenol.

[0008] In step 1, the molar ratio of di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder and 4,4'-dicyclohexylmethane diisocyanate is 0.9-1.1:1:0.9-1.1.

[0009] In step 1, the mass ratio of the mixture of di(2-(methacryloyloxy)ethyl) phosphate, cashew nut phenol and 4,4'-dicyclohexylmethane diisocyanate to ethyl acetate is 1:3-5.

[0010] In step 1, the stirring temperature is 60-90℃ and the stirring time is 3-6 hours.

[0011] The specific process of step 2 is as follows: add the photoinitiator to the mixture after the reaction in step 1, continue stirring, remove air bubbles by vacuum drying, coat it onto the glass substrate with a coater, and then cure it under ultraviolet light.

[0012] In step 2, the curing time is 60-120 seconds.

[0013] The second technical solution adopted in this invention is a light-cured flame-retardant coating with added cashew phenol, which is prepared by the above-mentioned method for preparing a light-cured flame-retardant coating with added cashew phenol.

[0014] The beneficial effects of this invention are as follows: (1) The present invention uses di(2-(methacryloyloxy)ethyl) phosphate as a flame retardant, which does not produce highly toxic dioxins and furans under combustion, and is environmentally friendly and human health friendly.

[0015] (2) The present invention uses photocurable polymer monomers, which react rapidly when coated on the surface, are portable and efficient, and can significantly reduce the film formation time of the material.

[0016] (3) The flame retardant of the flame retardant coating of the present invention is only 35%, the limiting oxygen index is 28%, and the main thermal decomposition temperature is greater than 350℃. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the synthesis route of the photocurable flame retardant coating with added cashew phenol in this invention; Figure 2(a) is the thermogravimetric curve (b1) of the light-cured flame-retardant coating with added cashew phenol in this invention; Figure 2(b) is a micro-thermogravimetric curve (b2) of the light-cured flame-retardant coating with added cashew phenol of the present invention; Figure 2(c) is the differential scanning calorimetry curve (b3) of the photocurable flame retardant coating with added cashew phenol of the present invention; Figure 3(a) is a heat release rate curve (c1) of the cotton fabric with the light-cured flame-retardant coating of cashew phenol added according to the present invention and the original cotton fabric. Figure 3(b) is a curve showing the total heat release of the cotton fabric with the light-cured flame-retardant coating of cashew phenol added according to the present invention and the original cotton fabric (c2). Figure 4(a) shows the smoke release rate curves of the cotton fabric with the light-cured flame-retardant coating of cashew phenol added according to the present invention and the original cotton fabric (c3). Figure 4(b) is a curve showing the total smoke emission of the cotton fabric with the light-cured flame-retardant coating of cashew phenol added according to the present invention and the original cotton fabric (c4). Detailed Implementation

[0018] The following detailed description is provided in conjunction with specific implementation methods.

[0019] The present invention discloses a method for preparing a photocurable flame-retardant coating with added cashew nut shell powder. The method mainly involves reacting di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder, and 4,4'-dicyclohexylmethane diisocyanate to prepare a foaming material, specifically including the following steps: Step 1, the synthesis of polyurethane acrylic resin monomers containing cashew phenol, is carried out as follows: Under nitrogen atmosphere, di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder, 4,4'-dicyclohexylmethane diisocyanate (HMDI) and ethyl acetate were poured into a flask and stirred. After stirring, the ethyl acetate was removed by rotary evaporation.

[0020] In step 1, the molar ratio of di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder, and 4,4'-dicyclohexylmethane diisocyanate is 0.9-1.1:1:0.9-1.1, the mass ratio of the mixture of di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder, and 4,4'-dicyclohexylmethane diisocyanate to ethyl acetate is 1:3-5, the temperature is 60-90℃, and the time is 3-6 h.

[0021] Step 2: Curing of the polyurethane acrylic resin monomer containing cashew phenol.

[0022] The specific process of step 2 is as follows: add photoinitiator 1173 to the mixture after the reaction in step 1, continue stirring, remove air bubbles by vacuum drying, coat it onto the glass substrate with a coater, and then cure it under irradiation with a 500W ultraviolet lamp.

[0023] In step 2, the amount of photoinitiator 1173 is 3-5% of the mass of the product from step 1, and the curing time is 60-120 seconds.

[0024] Example 1 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 9.72 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 60 °C for 6 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (3% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0025] Example 2 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 16.2 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 90 °C for 63 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (5% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0026] Example 3 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 12.96 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 75 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (4% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0027] Example 4 1.16 g of di(2-(methacryloyloxy)ethyl) phosphate, 0.93 g of HMDI, 0.91 g of cashew nut shell phenol, and 12.96 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 75 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (4% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0028] Example 5 1.41 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.14 g of HMDI, 0.91 g of cashew nut shell phenol, and 12.96 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 75 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (4% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0029] Example 6 1.2 g of di(2-(methacryloyloxy)ethyl) phosphate, 1 g of HMDI, 0.9 g of cashew nut shell phenol, and 12.96 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 75 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (4% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0030] The above embodiment 3 is a preferred embodiment of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

[0031] Comparative Example 1 The purchased cotton fabric was cut into 5 cm × 5 cm pieces and cleaned at least three times in an ultrasonic cleaner using anhydrous ethanol and deionized water to remove contaminants from the surface. The fabric was then dried in an 80°C oven for 1 hour without any surface coating. In contrast to Example 3, the cotton fabric in Comparative Example 1 was not treated with a surface coating.

[0032] Table 1

[0033] As shown in Figures 2(a), 2(b), 2(c), and Table 1, the weight loss behavior of Example 3 was analyzed using thermogravimetric analysis. It can be seen that the rapid degradation process of the flame-retardant coating occurs within the temperature range of 200-500℃, with T10% and T50% observed at 260.21℃ and 376.28℃, respectively. Furthermore, the residual carbon rate at 800℃ is 27.58%, indicating that the high thermal stability of the flame-retardant coating originates from BEMP and the cross-linking structure. The calculated LOI of the flame-retardant coating is 27.58, close to the tested LOI value of 28, which signifies the high flame retardancy of the cured film.

[0034] Figures 3(a) and 3(b) show the heat release rate (HRR) and total heat release (THR) curves of Example 3 and Comparative Example 1. The heat release rate shows a rapid upward trend in the initial stage of combustion, and then gradually decreases after reaching a peak. As can be seen from Figure 3(a), compared with Comparative Example 1, the heat release rate curve of the flame-retardant cotton fabric significantly decreased after adding the polyurethane acrylic resin monomer containing cashew phenol, indicating that the polyurethane acrylic resin monomer containing cashew phenol can reduce the heat released by the flame-retardant cotton fabric during combustion. The peak heat release rate of the original cotton fabric was 426.77 kW / m². 2 The peak heat release rate of flame-retardant cotton fabric decreased to 71.86 KW / m after adding polyurethane acrylic resin monomers containing cashew phenol. 2 This indicates that the polyurethane acrylic resin monomer containing cashew phenol can effectively suppress the exothermic reaction during combustion. As can be seen from Figure 3(b), the total heat release of Comparative Example 1 was 7.72 MJ / m³. 2 The total heat release of flame-retardant cotton fabric is reduced to 2.53 MJ / m². 2The lower total heat release indicates that less of the matrix material of the flame-retardant cotton fabric participates in combustion, while a larger portion forms condensed carbon. Figures 4(a) and 4(b) show that the total smoke production (TSP) of the original cotton fabric is 2.24 m³. 2 However, after adding a polyurethane acrylic resin monomer containing cashew phenol, the total smoke content of the cotton fabric was 1.07m³. 2 The addition of polyurethane acrylic resin monomers containing cashew phenols reduced the total smoke generation of cotton fabrics. In terms of smoke emission rate, the smoke emission rate (SPR) of the original cotton fabric was 0.128 m³ / s. 2 / s, while after adding polyurethane acrylic resin monomers containing cashew phenol, the smoke emission rate of cotton fabric was 0.03m. 2 The data above shows that polyurethane acrylic resin monomers containing cashew nut shell phenol exhibit good flame retardant properties. Polyurethane acrylic resin monomers containing cashew nut shell phenol possess certain flame retardant properties.

[0035] This invention uses cashew phenol, 4,4'-dicyclohexylmethane diisocyanate and di(2-(methacryloyloxy)ethyl) phosphate to generate a polymer, which can be used to prepare a photocurable flame retardant coating through structural design without adding halogenated flame retardants. The limiting oxygen index is 28% and the main thermal decomposition temperature is greater than 350℃.

[0036] Example 7 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 9.72 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 70 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (3% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0037] Example 8 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 9.72 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 80 °C for 5 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (3% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 100 s to obtain a flame-retardant coating.

[0038] Example 9 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 9.72 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 90 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (3% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm) for 120 s to obtain a flame-retardant coating.

[0039] Example 10 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 9.72 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 70 °C for 5 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (3% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm). Curing was stopped after 70 s to obtain a flame-retardant coating.

[0040] Example 11 1.29 g of di(2-(methacryloyloxy)ethyl) phosphate, 1.04 g of HMDI, 0.91 g of cashew nut shell phenol, and 9.72 g of ethyl acetate solvent were placed in a three-necked round-bottom flask. Under a nitrogen atmosphere, the reaction mixture was stirred at 600 rpm and heated to 80 °C for 4 h. Finally, the ethyl acetate solvent was removed by rotary evaporation, yielding a light yellow, transparent, viscous liquid. This light yellow, transparent, viscous liquid was mixed with photoinitiator 1173 (3% of the total mass) using a mechanical stirrer for 10 min. After vacuum drying to remove air bubbles, the mixture was coated onto a woven fabric using a 100 μm coater. The coating was then cured under UV irradiation (using a 500 W mercury lamp, 500 mm distance between the lamp and the sample, and a dominant wavelength of 365 nm) for 80 s to obtain a flame-retardant coating.

Claims

1. A method for preparing a photocurable flame-retardant coating with added cashew phenol, characterized in that: Specifically, the steps include the following: Step 1: Synthesize polyurethane acrylic resin monomers containing cashew phenol; Step 2: Curing the product obtained in Step 1.

2. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 1, characterized in that: The specific process of step 1 is as follows: Under nitrogen atmosphere, di(2-(methacryloyloxy)ethyl) phosphate, cashew phenol, 4,4'-dicyclohexylmethane diisocyanate and ethyl acetate are poured into a flask and stirred. After stirring, the ethyl acetate is removed by rotary evaporation to obtain the polyurethane acrylic resin monomer containing cashew phenol.

3. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 2, characterized in that: In step 1, the molar ratio of di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder, and 4,4'-dicyclohexylmethane diisocyanate is 0.9-1.1:0.9-1.1:0.9-1.

1.

4. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 3, characterized in that: In step 1, the molar ratio of di(2-(methacryloyloxy)ethyl) phosphate, cashew nut shell powder, and 4,4'-dicyclohexylmethane diisocyanate is 0.9-1.1:0.9-1.1:0.9-1.

1.

5. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 4, characterized in that: In step 1, the mass ratio of the mixture of di(2-(methacryloyloxy)ethyl) phosphate, cashew phenol and 4,4'-dicyclohexylmethane diisocyanate to ethyl acetate is 1:3-5.

6. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 4, characterized in that: In step 1, the stirring temperature is 60-90℃ and the stirring time is 3-5h.

7. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 6, characterized in that: The specific process of step 2 is as follows: add the photoinitiator to the mixture after the reaction in step 1, continue stirring, remove air bubbles by vacuum drying, coat it onto the glass substrate with a coater, and then cure it under ultraviolet light.

8. The method for preparing a photocurable flame-retardant coating with added cashew phenol according to claim 7, characterized in that: In step 2, the curing time is 60-120 seconds.

9. A light-cured flame-retardant coating with added cashew phenol is prepared by the method for preparing a light-cured flame-retardant coating with added cashew phenol as described in any one of claims 1 to 8.

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