Bamboo tar-containing epoxy resin fireproof coating and preparation method thereof

Abstract

The invention discloses an epoxy resin fireproof coating containing bamboo tar and a preparation method of the epoxy resin fireproof coating. The epoxy resin fireproof coating containing bamboo tar is prepared from the following raw materials in percentage by mass: 43-50% of epoxy resin, 21-25% of a polyamide curing agent, 2-9% of bamboo tar, 1-6% of a cross-linking agent, 6.5-7.5% of a flame retardant and 15-17.5% of a diluent, wherein the sum of all the components is 100%. The fireproof coating provided by the invention not only has a remarkable fireproof effect, but also fully utilizes 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 in particular relates to an epoxy resin fire-retardant coating containing bamboo tar and a preparation method thereof. Background Art

[0002] According to data released by the National Fire and Rescue Administration, in 2023, the national fire rescue team received about 878,000 warnings for urban and rural fire fighting, accounting for about 41.1% of all types of warnings. Even in the first half of 2023, the average daily number of fires in the country exceeded 3,000, resulting in 959 deaths, 1,311 injuries, and direct property losses of 3.94 billion yuan. Faced with the huge casualties and economic and property losses caused by fires, we must always be vigilant about possible fire hazards and build a strong sense of fire safety. At the same time, we should also actively engage in the development of flame retardant and fireproof materials.

[0003] Fire retardant coating is one of the simplest and most effective ways to protect furniture, kitchen cabinets, home appliances, interior decoration, etc. Compared with directly adding flame retardant fillers to the substrate, applying flame retardant coating on the substrate surface will not have a significant impact on the mechanical properties of the substrate itself. In addition, the method of applying flame retardant coating does not need to consider the compatibility of flame retardant fillers with the substrate, the amount of flame retardant fillers, and the dispersibility of flame retardant fillers under different amounts. In addition, flame retardant coatings are applicable to a wider range of substrates, such as wood, steel, and plastic parts.

[0004] Bamboo tar is a by-product of bamboo distillation process. It has high viscosity. It will not only cause equipment blockage, but also cause great harm to the environment if it is discarded at will. As a biomass tar, bamboo tar is mainly composed of phenol and other aromatic hydrocarbons. Since aromatic hydrocarbons tend to form carbon when burned, bamboo tar can be used as a carbonizing agent in the flame retardant system, which will further improve the flame retardant ability of fire retardant coatings. Introducing bamboo tar as a carbonizing agent into epoxy resin fire retardant coatings is a method of making full use of its molecular structure characteristics. This is not only in line with today's environmental protection concept, but also a new way to achieve high-value conversion of bamboo tar. Summary of the invention

[0005] The invention provides an epoxy resin fireproof coating containing bamboo tar and a preparation method thereof. The fireproof coating provided by the invention not only has a significant fireproof effect, but also makes full use of the waste bamboo tar in the process of bamboo charcoal production.

[0006] The epoxy resin fire retardant coating containing bamboo tar of the present invention is processed and prepared from the following raw materials by mass percentage: 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 the polyamide 651 is 1.8-2.2:1, preferably 2:1.

[0010] The bamboo tar is a byproduct of bamboo dry distillation 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 the 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 2-4:1, 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: 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.

[0016] Step 2: When using, add polyamide curing agent to the dispersed material and mix well to obtain epoxy resin fire retardant coating containing bamboo tar. Note that it should be used as soon as possible after mixing.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The epoxy resin as the matrix makes the obtained coating more widely applicable and can be applied to a variety of different substrates, such as wood, steel and plastic parts. At the same time, using bamboo tar as a charring agent in the flame retardant system not only provides a new way for the high-value conversion of bamboo tar, but also conforms to the current environmental protection concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the Fourier transform infrared spectrum of bamboo tar.

[0019] Figure 2 This is the reaction mechanism of bamboo tar and cross-linking agent (taking 4-ethylphenol as an example).

[0020] Figure 3 These are optical photographs of Example 2 before (a) and after (b) combustion in the fire resistance test.

[0021] Figure 4 This is the fire test process of Example 2. (a), (b), (c), (d), and (e) are optical images at the start of combustion, the 5th minute, the 10th minute, the 15th minute, and the burn-through, respectively. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative ideas belong to the scope of protection of the present invention. Embodiment 1:

[0023] Step 1: Weigh 100 g of epoxy resin E44, 5 g of bamboo tar, 3.3 g of crosslinking agent, 15 g of ammonium polyphosphate and 35 g of diluent and put them into a mixing tank, and disperse them at 500 r / min for 1 h. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0024] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0025] 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. Embodiment 2:

[0026] Step 1: Weigh 100 g of epoxy resin E44, 10 g of bamboo tar, 6.6 g of crosslinking agent, 15 g of ammonium polyphosphate and 35 g of diluent and put them into a mixing tank and disperse them at 500 r / min for 1 h. 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 well 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. Embodiment 3:

[0029] Step 1: Weigh 100 g of epoxy resin E44, 15 g of bamboo tar, 10 g of crosslinking agent, 15 g of ammonium polyphosphate and 35 g of diluent and put them into a mixing tank, and disperse them at 500 r / min for 1 h. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0030] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0031] 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. Embodiment 4:

[0032] 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 and put them into a mixing tank and disperse them at 500 r / min for 1 h. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0033] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0034] 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. Comparative Example 1:

[0035] Step 1: Weigh 100 g of epoxy resin E44, 6.6 g of crosslinker, 15 g of ammonium polyphosphate and 35 g of diluent and put them into a mixing tank, and disperse them at 500 r / min for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0036] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0037] 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. Comparative Example 2:

[0038] Step 1: Weigh 100 g of epoxy resin E44, 10 g of bamboo tar, 6.6 g of crosslinker and 35 g of diluent and put them into a mixing tank, and disperse them at 500 r / min for 1 h. 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 well 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. Comparative Example 3:

[0041] Step 1: Weigh 100 g of epoxy resin E44, 6.6 g of crosslinker, 25 g of ammonium polyphosphate and 35 g of diluent and put them into a mixing tank, and disperse them at 500 r / min for 1 hour. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0042] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0043] 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. Comparative Example 4:

[0044] Step 1: Weigh 100 g of epoxy resin E44, 25 g of bamboo tar, 6.6 g of crosslinker and 35 g of diluent and put them into a mixing tank, and disperse them at 500 r / min for 1 h. The mass ratio of xylene to n-butanol in the diluent is 3:1.

[0045] Step 2: When using, add 50 g of polyamide curing agent to the dispersed material and mix well to obtain the epoxy resin fire retardant coating containing bamboo tar.

[0046] 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.

[0047] 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 "Surface Fire Retardant Coatings", and the results are as follows: .

[0048] Embodiment 1-4 adjusts the proportion of bamboo tar and ammonium polyphosphate, verifies the fireproof performance of the modified coating. Compared with the embodiment, comparative examples 1-4 are further adjusted on the basis of the optimal proportion of bamboo tar and ammonium polyphosphate, in order to explore the specific role of ammonium polyphosphate and bamboo tar in the combustion process. As can be seen from embodiments 1-4, the bamboo tar with a mass fraction of 4.61% added in embodiment 2 has the best flame retardant effect, and the fireproof time reaches 20.2 minutes. Compared with comparative example 1 without adding bamboo tar, the fireproof time is improved by 741.67%. This is because bamboo tar contains a large amount of aromatic ring structures, which react with a crosslinking agent under high temperature conditions to form a protective carbon layer with excellent heat resistance. At the same time, ammonium polyphosphate is decomposed by heat to produce inert gas, which expands the carbon layer. This expanded carbon layer has a good effect of hindering heat and gas transfer, thereby enabling the prepared coating to protect the substrate well.

[0049] By comparing Example 2 with Comparative Examples 3 and 4, it is found that adding only bamboo tar or ammonium polyphosphate has little effect on improving the fire resistance of wood plywood, which can also prove that bamboo tar and ammonium polyphosphate have a synergistic flame retardant effect during the combustion process.

[0050] 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, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be covered by 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%, cross-linking agent 1-6%, flame retardant 6.5-7.5%, diluent 15-17.5%, all components total 100%.

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, the amine value is 400-440 mgKOH / g, and the viscosity is 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 cross-linking agent is 4,4'-dihydroxydiphenyl ether.

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

1.

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

1.

8. The epoxy resin fire retardant coating according to claim 1, characterized in that: The flame retardant is ammonium polyphosphate.

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

10. The method for preparing the epoxy resin fire retardant coating containing bamboo tar according to any one of claims 1 to 9, characterized in that The steps include: Step 1: Add epoxy resin, bamboo tar, cross-linking agent, flame retardant and diluent into a batching tank according to the proportion, and stir and disperse them evenly; Step 2: When using, add polyamide curing agent to the dispersed material, mix evenly to obtain the epoxy resin fire retardant coating containing bamboo tar.

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