Method for preparing enhanced waterproof flame-retardant coating by using waste plastic track powder as additive

Abstract

The invention discloses a method for preparing an enhanced waterproof flame-retardant coating by using waste plastic track powder as an auxiliary agent. According to the invention, the waste plastic runway powder is used as a waterproof modifier and an auxiliary flame retardant, and the waste plastic runway powder is mixed with the epoxy resin coating, so that the waterproof and flame-retardant properties of the coating are remarkably improved, and the application range of the coating in the fields of wooden furniture, ancient building protection and the like is expanded. By recycling and reusing the waste plastic runway, the environment problem is solved, cyclic utilization of resources is promoted, and the concept of green and sustainable development is met.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardant coatings, and specifically relates to a method for preparing an enhanced waterproof 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. It has the advantages of being renewable, easy to process, beautiful, and lightweight. However, due to its flammable nature, wood has potential safety hazards during use. When a fire occurs, wood can burn quickly 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. When encountering fire, they can play a flame-retardant role through various mechanisms, 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 because of their high elasticity, anti-skid and wear-resistant advantages. However, generally speaking, plastic tracks need to be maintained and replaced after 5-10 years of use. According to the conservative estimate of the my country Sporting Goods Association, there will be 4.91×10 8 m 2 The plastic runway needs to be replaced, which will generate a lot of waste. How to properly dispose of these waste plastic runways is a serious practical problem. Therefore, for the sake of environmental protection and recycling of waste resources, it is very necessary to properly recycle the waste plastic runway. However, there are no related reports at home and abroad on the application of waste plastic runways in flame retardant coatings. Summary of the invention

[0004] In view of 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, the waterproof and flame-retardant properties of the coating are significantly improved, and its application range in the fields of wooden furniture and ancient building protection is expanded. 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, and has good covering 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 uses waste plastic track powder as an auxiliary agent to prepare an enhanced waterproof and flame-retardant coating, comprising the following steps: Step 1: Use water flotation to screen the crushed waste plastic track particles into heavy powder with a density greater than water and light powder with a density less than water. Put the heavy powder and light powder into a drying oven respectively to remove moisture.

[0006] Step 2: Add ammonium polyphosphate, pentaerythritol, zinc oxide and heavy powder into a ball mill according to proportion and mix them by ball milling.

[0007] Step 3: Add the ball-milled product, epoxy resin and polyamide curing agent into a reactor, and further stir to obtain a mixed coating.

[0008] Step 4: Apply the mixed coating obtained in step 3 evenly to the surface of the wood to be protected.

[0009] Step 5: Spray an appropriate amount of lightweight powder evenly on the coating surface with the help of airflow.

[0010] Step 6: Spray anhydrous ethanol on the surface of the light powder cover coating.

[0011] Step 7: Bake the coating at high temperature or blow it with hot air.

[0012] The waste plastic track comes from waste during the renovation of sports fields, playgrounds or pedestrian walkways, and is crushed and screened to form particles with a diameter of ≤150 μm.

[0013] The raw material composition by mass is as follows: 80 parts of epoxy resin (E44 type), 20 parts of polyamide type curing agent, 10 parts of ammonium polyphosphate, 5 parts of pentaerythritol, 4 parts of zinc oxide, 1-20 parts of heavy powder.

[0014] Furthermore, in step 1, the drying temperature is 90° C. and the time is 12 h.

[0015] Furthermore, in step 2, the ball milling time is 2 h and the ball mill speed is 50 rpm.

[0016] Furthermore, in step 3, the stirring temperature is 25° C., the stirring time is 30 min, and the rotation speed is 100 rpm.

[0017] Furthermore, in step 4, the coating thickness is 400 μm.

[0018] Furthermore, in step 5, the surface density of the sprayed light powder is 100 g / m 2 .

[0019] Furthermore, in step 6, the spraying amount of anhydrous ethanol is 100 mL / m 2 .

[0020] Furthermore, in step 7, the temperature of high baking or hot air blowing is 90° C. and the time is 10 min.

[0021] According to the test results, the main components of light powder are organic polymers, including polyurethane and ethylene propylene rubber, etc.; the main components of heavy powder are inorganic substances coated with a small amount of organic matter, including calcium carbonate and silicon dioxide, etc. Ball milling the heavy powder with ammonium polyphosphate, pentaerythritol and zinc oxide promotes the physical and chemical fusion of several 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 surface of pentaerythritol and zinc oxide. In this way, not only can the dispersion homogeneity of heavy powder, ammonium polyphosphate, pentaerythritol and zinc oxide in the coating system be significantly improved, but also the speed of zinc oxide catalyzing the decomposition of ammonium polyphosphate can be increased, thereby accelerating the induction of calcium carbonate decomposition in the heavy powder, producing carbon dioxide, and synergistic flame retardant. At the same time, the light powder on the surface can form a dense hydrophobic protective layer on the surface of the coating because of its large amount of organic polymers.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention utilizes waste plastic track powder to enhance the waterproofness and flame retardancy of the coating, solves the problem of recycling and reusing waste plastic tracks, avoids the waste of solid waste resources, reduces the development of natural resources, alleviates environmental pressure, and promotes sustainable development. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with specific embodiments, but the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] 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.

[0025] Embodiment 1:

[0026] This embodiment prepares the enhanced waterproof flame retardant coating according to the following steps: 1. Use water flotation method to screen the crushed waste plastic track particles into heavy powder with density greater than water and light powder with density less than water; put the heavy powder and light powder into a drying oven with a preset temperature of 90°C for 12 hours to remove moisture.

[0027] 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 the ball mill in proportion, mix for 2 hours, and the ball mill speed is 50 rpm.

[0028] 3. Add the ball-milled product, 16 parts of epoxy resin and 4 parts of curing agent into the reactor and stir for 30 min at a speed of 100 rpm and a temperature of 25°C.

[0029] 4. Apply the above mixture evenly to the surface of the wood to be protected with a thickness of 400 μm.

[0030] 5. Spray an appropriate amount of lightweight powder evenly on the coating surface with the help of airflow, with a surface density of 100 g / m 2 .

[0031] 6. Spray anhydrous ethanol on the surface of the powder coating of the waste plastic track, 100 mL / m 2 .

[0032] 7. Bake at 90℃ or blow the coating surface with 90℃ hot air for 10 min.

[0033] Embodiment 2:

[0034] This embodiment adopts the same method as that of Embodiment 1 to prepare a fire-retardant and hydrophobic coating reinforced with waste plastic track powder as a flame retardant, with the difference being 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.

[0035] Embodiment 3:

[0036] This embodiment adopts the same method as that of Embodiment 1 to prepare a fire-retardant and hydrophobic coating reinforced with waste plastic track powder as a 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 other components and amounts remain unchanged.

[0037] 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 protection scope of the present invention.

[0038] Comparative Example 1: 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.

[0039] 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.

[0040] Comparative Example 2: 1. Use water flotation method to screen the waste plastic track powder into heavy powder with density greater than water and light powder with density less than water; put the heavy powder and light powder into a drying oven with a preset temperature of 90°C for 12 hours to remove moisture.

[0041] 2. Add 16 parts of epoxy resin and 4 parts of epoxy resin curing agent into the reactor and stir for 30 min at a speed of 100 rpm and a temperature of 25 °C.

[0042] 3. Apply the mixed paint evenly to the surface of the wood board with a thickness of 400 μm.

[0043] 4. Spray an appropriate amount of light powder with a diameter less than 20 μm evenly on the coating surface with the help of airflow, with a surface density of 100 g / m 2 .

[0044] 5. Spray anhydrous ethanol on the surface of the powder coating of the waste plastic track, 100 mL / m 2 .

[0045] 6. Bake at 90℃ or blow the coating surface with 90℃ hot air for 10 min.

[0046] Comparative Example 3: 1. Use water flotation method to screen the waste plastic track powder into heavy powder with density greater than water and light powder with density less than water.

[0047] 2. Place the heavy powder in a drying oven with a preset temperature of 90°C for 12 hours to remove moisture.

[0048] 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 and mix for 2 hours at a ball mill speed of 50 rpm.

[0049] 4. Add the ball-milled product, 16 parts of epoxy resin and 4 parts of curing agent into the reactor and stir for 30 min at a speed of 100 rpm and a temperature of 25°C.

[0050] 5. Apply the mixed paint evenly to the surface of the wooden board with a thickness of 400μm.

[0051] Comparative Example 4: 1. Add 10 parts of ammonium polyphosphate, 10 parts of pentaerythritol and 4 parts of zinc oxide into a ball mill in proportion and mix for 2 hours at a ball mill speed of 50 rpm.

[0052] 2. Add the ball-milled product, 16 parts of epoxy resin and 4 parts of curing agent into the reactor and stir for 30 min at a speed of 100 rpm and a temperature of 25°C.

[0053] 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.

[0054]

[0055] * Fire resistance time refers to the reference national standard GB12441-2018. The sample is placed on an ethanol fire, and the outer flame of the flame contacts 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 be burned through.

[0056] According to Table 1, from Example 1 to Example 3, as the amount of waste plastic track powder increases, the flame retardant properties of the coating are continuously improved, including the limiting oxygen index and the fire resistance time. This shows that waste plastic track powder is beneficial to improving the flame retardant properties of epoxy resin wood coatings.

[0057] The data of comparative example 1 show that the sample coated with only epoxy resin coating has almost no flame retardant properties, which indicates that epoxy resin coating cannot improve the flame retardant properties of wood boards, and its surface is hydrophilic rather than hydrophobic. The data of comparative example 2 show that there is only waste plastic runway powder but no ammonium polyphosphate, and the coating still has no flame retardant properties, but the surface hydrophobicity is greatly improved. It shows that heavy waste plastic runway powder cannot be used alone as a flame retardant, but lightweight powder can effectively improve the surface hydrophobicity of the coating. The data of comparative example 3 show that when ammonium polyphosphate and heavy waste plastic runway powder are contained in the coating, the coating has flame retardant properties, but due to the lack of lightweight waste plastic runway powder, the surface hydrophobicity of the coating is poor. The data of comparative example 4 show that when only ammonium polyphosphate is added but no heavy waste plastic runway powder is added, the composite coating has flame retardant properties, but the limiting oxygen index and fire resistance time are lower than those of comparative example 3, which shows that the heavy plastic runway powder has a flame retardant effect and can improve the flame retardant properties of the composite coating.

[0058] The coating compositions of Example 1 and Comparative Example 3 are similar, both containing the same amount of heavy waste plastic track powder and ammonium polyphosphate, etc., so their limiting oxygen index and fire resistance time are similar.

[0059] In summary, heavy waste plastic runway powder can synergistically improve the flame retardant properties of epoxy resin coatings with ammonium polyphosphate, while light waste plastic runway powder can improve the surface hydrophobicity of coatings. Waste plastic runway powder can be used as a multifunctional additive to improve the comprehensive performance of epoxy resin coatings.

Claims

1. A method for preparing an enhanced waterproof and flame-retardant coating using waste plastic runway powder as an additive, characterized in that The steps include: Step 1: Use water flotation method to screen the crushed waste plastic track particles into heavy powder with a density greater than water and light powder with a density less than water, and put the heavy powder and light powder into a drying oven to remove moisture; Step 2: Add ammonium polyphosphate, pentaerythritol, zinc oxide and heavy powder into a ball mill according to proportion and mix them by ball milling; 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 lightweight 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, characterized in that: The waste plastic track is taken from the waste plastic track during the renovation of sports fields, playgrounds or pedestrian walkways, and is crushed and screened to form particles with a diameter of ≤150 μm.

3. The method according to claim 1, characterized in that: 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, characterized in that: In step 1, the drying temperature is 90°C and the drying time is 12 h.

5. The method according to claim 1, characterized in that: 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, characterized in that: 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, characterized in that: In step 4, the coating thickness is 400 μm.

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

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

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

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