A method for preparing an enhanced waterproof and flame-retardant coating using waste plastic runway powder as an additive

Abstract

The present invention discloses a method for preparing an enhanced waterproof and flame-retardant coating using waste plastic track powder as an auxiliary agent. By using waste plastic track powder as a waterproof modifier and auxiliary flame retardant and mixing it with epoxy resin coating, the present invention significantly enhances the coating's waterproof and flame-retardant properties, expanding its application in areas such as wooden furniture and ancient building protection. By recycling and reusing discarded plastic tracks, the present invention not only addresses environmental issues but also promotes resource recycling, in line with the concept of green and sustainable development.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame retardant coatings, and in particular relates to a method for preparing an enhanced waterproof and flame retardant coating by using waste plastic runway powder as an auxiliary agent. Background Art

[0002] Wood has been widely used in the fields of construction and furniture manufacturing since ancient times. It is one of the traditional building materials with the advantages of being renewable, easy to process, beautiful, and lightweight. However, due to its flammable nature, wood poses a potential safety hazard during use. When a fire occurs, wood can burn rapidly and spread the fire, posing a serious threat to life and property safety. In order to solve the above problems and improve the fire retardant properties of wood, the research and development of flame retardant wood coatings has become a focus of attention. Flame retardant wood coatings can form a protective film on the surface of wood, which can play a flame retardant role through various mechanisms when encountering fire, such as preventing heat from transferring to the interior of the wood, releasing fire extinguishing gases to inhibit the combustion reaction, and forming a charcoal layer on the surface of the wood to isolate heat and oxygen from transferring to the interior of the material.

[0003] Plastic tracks are widely used in various track and field sports venues due to their high elasticity, anti-skid and wear-resistant properties. However, generally speaking, plastic tracks need to be maintained and replaced after 5-10 years of use. According to a conservative estimate by the my country Sporting Goods Association, there will be 4.91×10 8 m 2 The need to replace plastic tracks generates a significant amount of waste. Proper disposal of these discarded tracks presents a serious challenge. Therefore, for environmental protection and resource conservation, proper recycling of discarded plastic tracks is essential. However, there are no reports, domestically or internationally, on the application of flame-retardant coatings on discarded plastic tracks. Summary of the Invention

[0004] In response to the actual demand for waterproof and flame-retardant coatings for wood and the problem of insufficient resource utilization of waste plastic tracks, the present invention provides a method for preparing an enhanced waterproof and flame-retardant coating using waste plastic track powder as an auxiliary agent. The present invention uses waste plastic track powder as a waterproof modifier and auxiliary flame retardant, and by mixing the waste plastic track powder with epoxy resin coating, it significantly improves the waterproof and flame-retardant properties of the coating, and expands its application range in the fields of wooden furniture, ancient building protection, etc. Compared with the traditional internal injection of flame retardants, the coating application method of the present invention is simpler and can effectively maintain the basic properties of wood without affecting its mechanical properties, apparent density, etc., and the coating is pink and opaque, with good hiding and decorative functions. Through the recycling and reuse of discarded plastic tracks, the present invention not only solves environmental problems, but also promotes the recycling of resources, which is in line with the concept of green and sustainable development.

[0005] The method of the present invention for preparing an enhanced waterproof and flame-retardant coating using waste plastic track powder as an additive comprises the following steps:

[0006] Step 1: Use water flotation to separate the crushed waste plastic track particles into heavy powder with a density greater than water and light powder with a density less than water. Place the heavy powder and light powder in a drying oven separately to remove moisture.

[0007] Step 2: Add ammonium polyphosphate, pentaerythritol, zinc oxide and heavy powder into a ball mill according to proportion and mix them by ball milling.

[0008] Step 3: Add the ball-milled product, epoxy resin, and polyamide curing agent into a reactor, and further stir to obtain a mixed coating.

[0009] Step 4: Apply the mixed coating obtained in step 3 evenly to the surface of the wood to be protected.

[0010] Step 5: Spray an appropriate amount of lightweight powder evenly on the coating surface with the help of airflow.

[0011] Step 6: Spray anhydrous ethanol on the surface of the light powder cover coat.

[0012] Step 7: Bake the coating at high temperature or blow it with hot air.

[0013] The waste plastic track comes from waste generated during the renovation of sports fields, playgrounds or pedestrian walkways, and is crushed and screened to form particles with a diameter of ≤150 μm.

[0014] The raw material composition by mass is as follows:

[0015] 80 parts of epoxy resin (E44 type), 20 parts of polyamide curing agent, 10 parts of ammonium polyphosphate, 5 parts of pentaerythritol, 4 parts of zinc oxide, 1-20 parts of heavy powder.

[0016] Furthermore, in step 1, the drying temperature is 90° C. and the drying time is 12 h.

[0017] Furthermore, in step 2, the ball milling time is 2 h and the ball mill speed is 50 rpm.

[0018] Furthermore, in step 3, the stirring temperature is 25° C., the stirring time is 30 min, and the rotation speed is 100 rpm.

[0019] Furthermore, in step 4, the coating thickness is 400 μm.

[0020] Furthermore, in step 5, the surface density of the sprayed light powder is 100 g / m 2 .

[0021] Furthermore, in step 6, the spraying amount of anhydrous ethanol is 100 mL / m 2 .

[0022] Furthermore, in step 7, the temperature of high baking or hot air blowing is 90° C., and the time is 10 min.

[0023] Chemical analysis revealed that the main components of the lightweight powder are organic polymers, including polyurethane and ethylene propylene rubber, while the main components of the heavy powder are inorganic substances coated with a small amount of organic matter, including calcium carbonate and silica. Ball-milling the heavy powder with ammonium polyphosphate, pentaerythritol, and zinc oxide promotes the physical and chemical fusion of these substances—the particle size becomes smaller after ball milling; and mechanical force is used to promote the breaking of organic bonds on the surface of the heavy powder to produce functional groups such as carboxyl, amino, and carbon free radicals, which then react with the hydroxyl functional groups on the surfaces of pentaerythritol and zinc oxide. This not only significantly improves the dispersion homogeneity of the heavy powder, ammonium polyphosphate, pentaerythritol, and zinc oxide in the coating system, but also increases the rate at which zinc oxide catalyzes the decomposition of ammonium polyphosphate, thereby accelerating the decomposition of calcium carbonate in the heavy powder, producing carbon dioxide and synergistically preventing flame retardancy. At the same time, the surface of the lightweight powder, due to its high content of organic polymers, can form a dense hydrophobic protective layer on the surface of the coating.

[0024] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0025] The present invention utilizes waste plastic track powder to enhance the waterproofness and flame retardancy of the coating, solves the problem of recycling and reuse of waste plastic tracks, avoids the waste of solid waste resources, reduces the development of natural resources, alleviates environmental pressure, and contributes to sustainable development. DETAILED DESCRIPTION

[0026] The technical solutions of the present invention are further described below with reference to specific embodiments. However, the embodiments described are only a portion of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] The waste plastic track powder used in the present invention is taken from a breathable plastic track that needs to be dismantled and refurbished after natural aging and wear, and the source is Henan Shengtian Sports Engineering Co., Ltd.

[0028] Example 1:

[0029] This embodiment prepares the enhanced waterproof flame retardant coating according to the following steps:

[0030] 1. Use water flotation to separate the crushed waste plastic track particles into heavy powder with a density greater than water and light powder with a density less than water; place the heavy powder and light powder in a drying oven with a preset temperature of 90°C for 12 hours to remove moisture.

[0031] 2. Add 10 parts of ammonium polyphosphate, 10 parts of pentaerythritol, 4 parts of zinc oxide and 5 parts of heavy waste plastic track powder into a ball mill in proportion, mix for 2 hours, and the ball mill speed is 50 rpm.

[0032] 3. Add the ball-milled product, 16 parts of epoxy resin and 4 parts of curing agent into the reactor and stir for 30 minutes at a speed of 100 rpm and a temperature of 25°C.

[0033] 4. Apply the above mixture evenly to the surface of the wood to be protected with a thickness of 400 μm.

[0034] 5. Spray an appropriate amount of light powder evenly on the coating surface with the help of airflow, with a surface density of 100 g / m 2 .

[0035] 6. Spray anhydrous ethanol on the surface of the powder coating of the waste plastic track at 100 mL / m 2 .

[0036] 7. Bake at 90℃ or blow the coating surface with 90℃ hot air for 10 minutes.

[0037] Example 2:

[0038] This embodiment uses the same method as Example 1 to prepare a fire-retardant and hydrophobic coating reinforced with waste plastic track powder as an auxiliary flame retardant, except that 5 parts of heavy waste plastic track powder are replaced with 10 parts of heavy waste plastic track powder, and the other components and amounts remain unchanged.

[0039] Example 3:

[0040] This embodiment uses the same method as Example 1 to prepare a fire-retardant and hydrophobic coating reinforced with waste plastic track powder as an auxiliary flame retardant, with the difference being that 5 parts of heavy waste plastic track powder are replaced with 15 parts of heavy waste plastic track powder, and the remaining components and amounts remain unchanged.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the patent scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0042] Comparative Example 1:

[0043] 1. First, add 16 parts of epoxy resin and 4 parts of epoxy resin curing agent into the reactor and stir for 30 minutes at a speed of 100 rpm and a temperature of 25°C.

[0044] 2. Apply the mixed coating evenly to the surface of the wood board with a thickness of 400 μm and cure it at room temperature.

[0045] Comparative Example 2:

[0046] 1. Use water flotation to separate the waste plastic track powder into heavy powder with a density greater than water and light powder with a density less than water; place the heavy powder and light powder in a drying oven with a preset temperature of 90°C for 12 hours to remove moisture.

[0047] 2. Add 16 parts of epoxy resin and 4 parts of epoxy resin curing agent into the reactor and stir for 30 minutes at a speed of 100 rpm and a temperature of 25 °C.

[0048] 3. Apply the mixed paint evenly to the surface of the wood board with a thickness of 400 μm.

[0049] 4. Spray an appropriate amount of light powder with a diameter of less than 20 μm evenly on the coating surface with the help of airflow, with a surface density of 100 g / m 2 .

[0050] 5. Spray anhydrous ethanol on the surface of the powder coating of the waste plastic track at 100 mL / m 2 .

[0051] 6. Bake at 90℃ or blow the coating surface with 90℃ hot air for 10 minutes.

[0052] Comparative Example 3:

[0053] 1. Use water flotation method to screen the waste plastic track powder into heavy powder with a density greater than water and light powder with a density less than water.

[0054] 2. Place the heavy powder in a drying oven with a preset temperature of 90°C for 12 hours to remove moisture.

[0055] 3. Add 10 parts of ammonium polyphosphate, 10 parts of pentaerythritol, 4 parts of zinc oxide and 5 parts of heavy powder into a ball mill in proportion, mix for 2 hours, and the ball mill speed is 50 rpm.

[0056] 4. Add the ball-milled product, 16 parts of epoxy resin and 4 parts of curing agent into the reactor and stir for 30 minutes at a speed of 100 rpm and a temperature of 25°C.

[0057] 5. Apply the mixed paint evenly to the surface of the wooden board with a thickness of 400μm.

[0058] Comparative Example 4:

[0059] 1. Add 10 parts of ammonium polyphosphate, 10 parts of pentaerythritol, and 4 parts of zinc oxide into a ball mill in proportion, mix for 2 hours, and rotate the ball mill at 50 rpm.

[0060] 2. Add the ball-milled product, 16 parts of epoxy resin and 4 parts of curing agent into the reactor and stir for 30 minutes at a speed of 100 rpm and a temperature of 25°C.

[0061] 3. Apply the mixed coating evenly to the surface of the wood board with a thickness of 400 μm and cure it at room temperature.

[0062]

[0063] *Fire resistance time refers to the reference to China National Standard GB12441-2018. The sample is placed on an ethanol fire, and the flame is allowed to contact the wood backing. The fire resistance time of the material is recorded. The fire resistance time is defined as the time it takes for the sample to burn through.

[0064] As shown in Table 1, from Example 1 to Example 3, as the amount of waste plastic track powder increases, the flame retardant properties of the coatings continue to improve, including the limiting oxygen index and fire resistance time. This indicates that waste plastic track powder is beneficial for improving the flame retardant properties of epoxy resin wood coatings.

[0065] The data from Comparative Example 1 shows that the sample coated with only epoxy resin coating has almost no flame retardancy, indicating that epoxy resin coating does not improve the flame retardancy of the wood board and that its surface is hydrophilic rather than hydrophobic. The data from Comparative Example 2 shows that the coating with only waste plastic track powder but no ammonium polyphosphate still has no flame retardancy, but the surface hydrophobicity is significantly improved. This indicates that heavy waste plastic track powder cannot be used alone as a flame retardant, but lightweight powder can effectively improve the surface hydrophobicity of the coating. The data from Comparative Example 3 shows that when the coating contains both ammonium polyphosphate and heavy waste plastic track powder, the coating is flame retardant, but the lack of lightweight waste plastic track powder results in poor surface hydrophobicity. The data from Comparative Example 4 shows that when only ammonium polyphosphate is added without heavy waste plastic track powder, the composite coating has flame retardancy, but the limiting oxygen index and fire resistance time are both lower than those of Comparative Example 3, indicating that the heavy waste plastic track powder has a flame retardant effect and can improve the flame retardancy of the composite coating.

[0066] The coating compositions of Example 1 and Comparative Example 3 are similar, both containing the same proportions of heavy waste plastic track powder and ammonium polyphosphate, etc., and therefore their limiting oxygen index and fire resistance time are similar.

[0067] In summary, heavy-weight waste plastic track powder can synergistically improve the flame retardancy of epoxy resin coatings with ammonium polyphosphate, while lightweight waste plastic track powder can enhance the surface hydrophobicity of the coating. Waste plastic track powder can serve as a multifunctional additive to enhance the overall performance of epoxy resin coatings.

Claims

1. A method for preparing an enhanced waterproof and flame-retardant coating using waste plastic track powder as an additive, characterized in that The steps include: Step 1: Use water flotation to separate the crushed waste plastic track particles into heavy powder with a density greater than water and light powder with a density less than water. Place the heavy powder and light powder in a drying oven to remove moisture. Step 2: Add ammonium polyphosphate, pentaerythritol, zinc oxide and heavy powder in proportion to a ball mill and mix them; Step 3: adding the ball-milled product, epoxy resin, and polyamide curing agent into a reactor, and further stirring to obtain a mixed coating; Step 4: evenly apply the mixed coating obtained in step 3 to the surface of the protected wood; Step 5: Spray an appropriate amount of light powder evenly on the coating surface with the help of airflow; Step 6: Spray anhydrous ethanol on the surface of the light powder coating; Step 7: Bake the coating at high temperature or blow it with hot air.

2. The method according to claim 1, wherein: The waste plastic track is taken from the plastic track waste during the renovation of sports fields, playgrounds or pedestrian walkways, and is formed into particles with a diameter of ≤150 μm after crushing and screening.

3. The method according to claim 1, wherein: The raw material composition by mass is as follows: 80 parts of epoxy resin, 20 parts of polyamide curing agent, 10 parts of ammonium polyphosphate, 5 parts of pentaerythritol, 4 parts of zinc oxide, and 1-20 parts of heavy powder.

4. The method according to claim 1, wherein: In step 1, the drying temperature is 90°C and the drying time is 12 h.

5. The method according to claim 1, wherein: In step 2, the ball milling time was 2 h and the ball mill speed was 50 rpm.

6. The method according to claim 1, wherein: In step 3, the stirring temperature is 25° C., the stirring time is 30 min, and the rotation speed is 100 rpm.

7. The method according to claim 1, wherein: In step 4, the coating thickness is 400 μm.

8. The method according to claim 1, wherein: In step 5, the surface density of the light powder sprayed is 100 g / m 2 .

9. The method according to claim 1, wherein: In step 6, the spraying amount of anhydrous ethanol is 100 mL / m 2 .

10. The method according to claim 1, wherein: In step 7, the temperature of high-temperature baking or hot air blowing is 90° C., and the time is 10 min.

Images