Epoxy resin fire retardant coating containing bamboo tar and preparation method thereof

Abstract

The invention discloses a bamboo tar-containing epoxy resin fire retardant coating and a preparation method thereof. The bamboo tar-containing epoxy resin fire retardant coating is processed and made from the following raw materials by mass percentage: 43-50% epoxy resin, 21-25% polyamide curing agent, 2-9% bamboo tar, 1-6% cross-linking agent, 6.5-7.5% flame retardant, and 15-17.5% diluent, with all components totaling 100%. The fire retardant coating provided by the present invention not only has a significant fireproofing effect, but also makes full use of the waste bamboo tar in the bamboo charcoal production process.

Description

Technical Field

[0001] The invention belongs to the technical field of fire retardant coatings, and particularly relates to an epoxy resin fire retardant coating containing bamboo tar and a preparation method thereof. Background Art

[0002] Fire-retardant coatings are one of the simplest and most effective methods for protecting furniture, kitchen cabinets, appliances, interiors, and more. Compared to directly adding flame-retardant fillers to a substrate, applying flame-retardant coatings to the surface of a substrate does not significantly affect the substrate's mechanical properties. Furthermore, applying flame-retardant coatings eliminates the need to consider issues such as the compatibility of the filler with the substrate, the filler dosage, and the dispersion of the filler at different dosages. Furthermore, flame-retardant coatings are suitable for a wider range of substrates, such as wood, steel, and plastics.

[0003] Bamboo tar, a byproduct of bamboo dry distillation, has high viscosity. It can not only clog equipment but also pose significant environmental risks if discarded carelessly. As a biomass tar, bamboo tar is primarily composed of phenol and other aromatic hydrocarbons. Because aromatic hydrocarbons tend to form char upon combustion, bamboo tar can be used as a charring agent in flame retardant systems, further enhancing the flame retardancy of fire-retardant coatings. Incorporating bamboo tar into epoxy resin fire-retardant coatings as a charring agent is a method that fully utilizes its molecular structure. This not only aligns with current environmental protection concepts but also represents a new approach to achieving high-value conversion of bamboo tar. Summary of the Invention

[0004] The present invention provides an epoxy resin fire retardant coating containing bamboo tar and a preparation method thereof. The fire retardant coating provided by the present invention not only has a significant fire retardant effect, but also fully utilizes the waste bamboo tar in the bamboo charcoal production process.

[0005] The epoxy resin fire retardant coating containing bamboo tar of the present invention is made from the following raw materials by mass percentage:

[0006] Epoxy resin 43-50%, polyamide curing agent 21-25%, bamboo tar 2-9%, cross-linking agent 1-6%, flame retardant 6.5-7.5%, diluent 15-17.5%, all components total 100%.

[0007] The epoxy resin is epoxy resin E44, and the epoxy value is between 0.41 and 0.47.

[0008] The polyamide curing agent is polyamide 651, the amine value is 400-440 mgKOH / g, and the viscosity is 1500-3000 mPa·s at 40°C.

[0009] The mass ratio of the epoxy resin E44 to polyamide 651 is 1.8-2.2:1, preferably 2:1.

[0010] The bamboo tar is a by-product of the bamboo dry distillation process and is a biomass tar, preferably secondary bamboo tar.

[0011] The cross-linking agent is 4,4'-dihydroxydiphenyl ether.

[0012] The mass ratio of the bamboo tar to the cross-linking agent is 1-3:1, preferably 1.5:1.

[0013] The flame retardant is ammonium polyphosphate, preferably high-polymerization ammonium polyphosphate; further, preferably, the polymerization degree of ammonium polyphosphate is n=1000.

[0014] The diluent is a mixture of xylene and n-butanol, and the mass ratio of xylene to n-butanol is 2 to 4:1, preferably 3:1.

[0015] The preparation method of the epoxy resin fire retardant coating containing bamboo tar of the present invention comprises the following steps:

[0016] Step 1: Add epoxy resin, bamboo tar, cross-linking agent, flame retardant and diluent into the mixing tank according to the proportion, and disperse at 500 r / min for 1 hour.

[0017] Step 2: When using, add polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar. Note that it must be used as soon as possible after mixing.

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

[0019] The epoxy resin matrix makes the resulting coating more widely applicable, allowing it to be applied to a variety of substrates, such as wood, steel, and plastics. Furthermore, using bamboo tar as a charring agent in flame retardant systems not only provides a new approach to converting bamboo tar into high-value products, but also aligns with current environmental protection concepts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the Fourier transform infrared spectrum of bamboo tar.

[0021] Figure 2 This is the reaction mechanism of bamboo tar and cross-linking agent (taking 4-ethylphenol as an example).

[0022] Figure 3 These are optical photographs before (a) and after (b) combustion in the fire resistance test of Example 2.

[0023] Figure 4 This is the fire resistance test process of Example 2. (a), (b), (c), (d), and (e) are optical images at the start of combustion, 5 minutes, 10 minutes, 15 minutes, and burn-through, respectively. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more clear, the following provides a clear and complete description of the technical solutions of the present invention. Obviously, the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive steps fall within the scope of protection of the present invention.

[0025] Example 1:

[0026] Step 1: Weigh 100 g of epoxy resin E44, 5 g of bamboo tar, 3.3 g of crosslinker, 15 g of ammonium polyphosphate, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0027] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0028] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0029] Example 2:

[0030] Step 1: Weigh 100 g of epoxy resin E44, 10 g of bamboo tar, 6.6 g of crosslinker, 15 g of ammonium polyphosphate, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0031] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0032] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0033] Example 3:

[0034] Step 1: Weigh 100 g of epoxy resin E44, 15 g of bamboo tar, 10 g of crosslinker, 15 g of ammonium polyphosphate, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0035] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0036] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0037] Example 4:

[0038] Step 1: Weigh 100 g of epoxy resin E44, 20 g of bamboo tar, 13.3 g of crosslinker, 15 g of ammonium polyphosphate, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0039] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0040] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0041] Comparative Example 1:

[0042] Step 1: Weigh 100 g of epoxy resin E44, 6.6 g of crosslinker, 15 g of ammonium polyphosphate, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0043] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0044] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0045] Comparative Example 2:

[0046] Step 1: Weigh 100 g of epoxy resin E44, 10 g of bamboo tar, 6.6 g of crosslinker, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0047] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0048] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0049] Comparative Example 3:

[0050] Step 1: Weigh 100 g of epoxy resin E44, 6.6 g of crosslinker, 25 g of ammonium polyphosphate, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0051] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0052] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0053] Comparative Example 4:

[0054] Step 1: Weigh 100 g of epoxy resin E44, 25 g of bamboo tar, 6.6 g of crosslinker, and 35 g of diluent into a mixing tank and disperse at 500 rpm for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0055] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0056] Step 3: Apply the obtained fire retardant coating on the wood plywood board, control the film thickness to 200 μm and dry it at room temperature for 24 h.

[0057] The fire retardant coatings prepared in Examples 1-4 and Comparative Examples 1-4 were tested for their performance in accordance with GB 12441-2018 “Fire Retardant Coatings for Surfaces”. The results are as follows:

[0058]

[0059] Examples 1-4 adjusted the proportions of bamboo tar and ammonium polyphosphate to verify the fire retardant properties of the modified coating. Compared to the examples, Comparative Examples 1-4 were further adjusted based on the optimal proportions of bamboo tar and ammonium polyphosphate to explore the specific effects of ammonium polyphosphate and bamboo tar during the combustion process. As can be seen from Examples 1-4, Example 2, which added 4.61% bamboo tar by mass, had the best flame retardant effect, with a fire resistance time of 20.2 minutes. Compared to Comparative Example 1, which did not add bamboo tar, the fire resistance time increased by 741.67%. This is because bamboo tar contains a large amount of aromatic ring structures, which react with the crosslinking agent under high temperature conditions to form a protective carbon layer with excellent heat resistance. At the same time, ammonium polyphosphate decomposes under heat to produce inert gases, causing the carbon layer to expand. This expanded carbon layer has a good effect of hindering heat and gas transfer, thereby enabling the prepared coating to effectively protect the substrate.

[0060] Comparative Example 2 and Comparative Examples 3 and 4 show that the addition of only bamboo tar or ammonium polyphosphate has little effect on the improvement of the fire resistance of wood plywood, which also proves that bamboo tar and ammonium polyphosphate have a synergistic flame retardant effect during combustion.

[0061] Note: The above examples are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Therefore, although this specification has described the present invention in detail with reference to the above examples, it should be understood by those skilled in the art that the present invention may still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. An epoxy resin fire retardant coating containing bamboo tar, characterized in that Made from the following raw materials by mass percentage: Epoxy resin 43-50%, polyamide curing agent 21-25%, bamboo tar 2-9%, crosslinking agent 1-6%, flame retardant 6.5-7.5%, diluent 15-17.5%, all components total 100%; The cross-linking agent is 4,4'-dihydroxydiphenyl ether; The flame retardant is ammonium polyphosphate.

2. The epoxy resin fire retardant coating according to claim 1, characterized in that: The epoxy resin is epoxy resin E44, and the epoxy value is between 0.41 and 0.

47.

3. The epoxy resin fire retardant coating according to claim 1, characterized in that: The polyamide curing agent is polyamide 651, with an amine value of 400-440 mgKOH / g and a viscosity of 1500-3000 mPa·s at 40°C.

4. The epoxy resin fire retardant coating according to claim 1, 2 or 3, characterized in that: The mass ratio of the epoxy resin to the polyamide curing agent is 1.8-2.2:

1.

5. The epoxy resin fire retardant coating according to claim 1, characterized in that: The mass ratio of the bamboo tar to the cross-linking agent is 1-3:

1.

6. The epoxy resin fire retardant coating according to claim 5, characterized in that: The mass ratio of the bamboo tar to the cross-linking agent is 1.5:

1.

7. The epoxy resin fire retardant coating according to claim 1, characterized in that: The diluent is a mixture of xylene and n-butanol.

8. The method for preparing the epoxy resin fire retardant coating containing bamboo tar according to any one of claims 1 to 7, characterized in that The steps include: Step 1: Add epoxy resin, bamboo tar, cross-linking agent, flame retardant and diluent into the mixing tank according to the proportion, and stir and disperse them evenly; Step 2: When using, add polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

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