High-performance rigid polyurea spraying process

Abstract

The invention belongs to the technical field of spraying. The invention provides a high-performance rigid polyurea spraying process which comprises the following steps: respectively injecting an isocyanate component and an amino compound into ISO and RES material storage tanks of a spraying machine, sealing top covers of the ISO and RES material storage tanks, turning on a main power supply of the spraying machine, circularly heating materials to 85 DEG C, setting the pressure of a spray gun of the spraying machine to be 80Kpa, and after the reading is stable for 10 minutes, stopping spraying; enabling the isocyanate component and the amino compound to quickly react to form a film in the spraying process according to the volume ratio of (1.08-1.12): 1, and spraying; the isocyanate component is prepared from toluene diisocynate, polypropylene glycol, low molecular weight polyurea coating polyol, an organic bismuth catalyst and a polymerization inhibitor; the amino compound is prepared from amino-terminated polyether, aromatic diamine, a chain extender and a defoaming agent. The shore hardness and the elongation at break of the generated polyurea resin can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of spraying technology, specifically relating to a high-performance rigid polyurea spraying process. Background Technology

[0002] Polyurea spraying technology, with its unparalleled comprehensive performance, environmental friendliness, and construction efficiency, has established an irreplaceable position in key fields such as building waterproofing and corrosion protection, industrial protection, transportation, and new energy. Against the backdrop of increasingly stringent environmental policies and ever-rising requirements for material performance and engineering efficiency, the application prospects of polyurea are extremely broad. Although facing challenges such as cost and construction barriers, with continuous technological advancements, gradual cost optimization, increased market awareness, and improved standards and specifications, polyurea spraying technology is expected to shine in more emerging fields, becoming a major force in the high-performance protection and specialty coating market. Polyurea spraying technology can be used in various industrial applications such as corrosion protection, waterproofing, explosion-proofing, and wear resistance. Application areas include chemical storage, wastewater treatment, reservoir corrosion and seepage prevention, transportation, roof waterproofing, oil and gas pipelines, mining equipment, and military protection. For example, the polyurea sealing system of the Hong Kong-Zhuhai-Macau Bridge immersed tunnel has a service life of over 50 years, reducing replacement frequency by 70% compared to traditional materials, indirectly reducing resource consumption.

[0003] Polyurea application releases virtually no harmful gases, significantly improving the working environment, reducing air pollution, and complying with increasingly stringent global environmental regulations. Polyurea coatings dry within seconds to minutes after spraying, drastically shortening the application cycle. This reduces equipment downtime and energy consumption (such as lighting, ventilation, and heating equipment operation time). A single application achieves the required thickness, avoiding repeated energy consumption and material waste from multiple coats. Its extended service life means a significant reduction in the number of refurbishments throughout the material's lifespan. It effectively protects pipelines, tanks, and equipment from corrosion, wear, and heat loss, maintaining their operational efficiency and reducing energy waste caused by equipment damage and leaks.

[0004] Polyurea, as a type of polymeric protective material, is rapidly reshaping the field of engineering protection thanks to its innovative molecular structure and designable performance. Polyurea, generated by the reaction of isocyanate components with amino compounds, retains the protective properties of traditional polymers while achieving a leapfrog breakthrough in performance through molecular design, demonstrating significant advantages in both technological innovation and application expansion. In existing technologies, as the spray volume ratio of isocyanate components to amino compounds increases (0.9→1.1), the curing time of the polyurea resin decreases. However, Shore hardness and elongation at break initially increase, but then begin to decrease after the spray volume ratio of isocyanate components to amino compounds exceeds 1.0. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a high-performance rigid polyurea spraying process that can effectively improve the Shore hardness and elongation at break of the generated polyurea resin.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The high-performance rigid polyurea spraying process involves injecting the isocyanate component and amino compound into the ISO and RES material storage tanks of the spraying machine, respectively. After sealing the top covers of the ISO and RES material storage tanks, the main power of the spraying machine is turned on to allow the material to circulate and heat to 85°C. The spray gun pressure of the spraying machine is set to 80 kPa. After the reading stabilizes for 10 minutes, the isocyanate component and amino compound react rapidly to form a film during the spraying process at a volume ratio of (1.08-1.12):1, and then the coating is carried out. The isocyanate component is prepared from toluene diisocyanate, polypropylene glycol, low molecular weight polyol, organic bismuth catalyst and polymerization inhibitor; the amino compound is prepared from amino-terminated polyether, aromatic diamine, chain extender and defoamer.

[0007] Further, the preparation method of the isocyanate component is as follows: The initial temperature is 20℃. A clean three-necked flask is purged and dried with nitrogen for 2 minutes. Under nitrogen replacement conditions, 355-365g of dehydrated toluene diisocyanate is added. Under mechanical stirring, the mixture is slowly heated to 20℃. 635-645g of dehydrated polypropylene glycol, 45-50g of low molecular weight polyol, 0.5-0.8g of organic bismuth catalyst, and 1.0-1.2g of polymerization inhibitor (BHT) are slowly added. The vacuum degree is then stabilized at 0.09Mpa, and the temperature is continuously raised to 80℃ for 2 hours. Then, the mixture is dehydrated under reduced pressure until no more bubbles are generated, thus obtaining the final product.

[0008] Furthermore, the method for treating the dehydrated toluene diisocyanate is as follows: heat the toluene diisocyanate in a clean three-necked flask to 115°C, and then filter it under reduced pressure after the thermometer reading stabilizes until no more bubbles are generated in the flask. Collect, seal, and store for later use.

[0009] Furthermore, the method for processing the dehydrated polypropylene glycol is as follows: add polypropylene glycol to a clean, dry three-necked flask, install the vacuum device and thermometer, place it in an oil bath, turn on the heating and vacuum pump, maintain a stable vacuum, and slowly raise the temperature to 120°C for 2 hours to obtain dehydrated PPG, which is then collected in a container, sealed, and stored in a vacuum drying oven for later use.

[0010] Furthermore, the low molecular weight polyol includes glycerol or glycerol.

[0011] Furthermore, the polymerization inhibitor is BHT.

[0012] Further, the preparation method of the amino compound is as follows: 950-1000g of terminal amino polyether, 40-45g of aromatic diamine, 1.4g of chain extender and 10g of defoamer are added sequentially to a three-necked flask, stirred evenly, heated and reacted for two hours, and then filtered under reduced pressure to remove water, thus obtaining the compound.

[0013] Furthermore, the terminal amino polyethers include D-2000, T-5000, and D-400.

[0014] Furthermore, the chain extender is DETDA (tetrafunctional).

[0015] Furthermore, the defoamer is BYK-168.

[0016] This application has the following beneficial effects: This invention specifies that the isocyanate component and the amino compound are in a volume ratio of (1.08-1.12):1 to rapidly react and form a film during the spraying process; furthermore, the isocyanate component is supplemented with low molecular weight polyol glycerol, and the amino compound is supplemented with aromatic diamine m-phenylenediamine; this can produce a synergistic effect, synergistically improving the Shore hardness and elongation at break of the polyurea coating film.

[0017] The addition of low-molecular-weight polyol glycerol to the isocyanate component consumes NCO, reduces the concentration of free NCO, buffers excess NCO, and lowers the risk of self-polymerization. It also maintains the integrity of the three-dimensional network through branched structure, avoiding local defects, and chemically crosslinks reconstruct a uniform crosslinked network. The addition of the aromatic diamine m-phenylenediamine to the amino compound increases hydrogen bond density, strengthens physical crosslinking, enhances hard segment crystallinity, and reinforces rigid units. Its bifunctional characteristics also maintain segment regularity and bridge flexible segments. This binary synergy (chemical crosslinking reconstruction + rigid unit reinforcement) expands / increases the optimal volume ratio threshold of the isocyanate component to the amino compound to 1.1:1, while simultaneously achieving further improvements in the Shore hardness and elongation at break of the polyurea coating. Attached Figure Description

[0018] Figure 1 This is a comparative trend chart of the Shore hardness data of polyurea coatings in Examples 1-3 and Comparative Examples 1-3 of the present invention; Figure 2 A comparative trend chart of the elongation at break data of polyurea coatings in Examples 1-3 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0019] The present application will be further described in detail below with reference to the embodiments.

[0020] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0021] Example 1 (I) The preparation method of the isocyanate component is as follows: The initial temperature is 20℃. Take a clean three-necked flask and dry it by purging with nitrogen for 2 minutes. Under nitrogen replacement conditions, add 360g of dehydrated toluene diisocyanate. Under mechanical stirring, slowly heat to 20℃. Slowly add 640g of dehydrated polypropylene glycol, 48g of glycerol, 0.7g of organic bismuth catalyst and 1.1g of polymerization inhibitor BHT. Then stabilize the vacuum degree at 0.09Mpa, continue to heat to 80℃ and react for 2h. Then dehydrate under reduced pressure until no more bubbles are generated, and the product is obtained.

[0022] The organic bismuth catalyst, bismuth neodecanoate, was purchased from Shandong Wantai Chemical Co., Ltd. The polymerization inhibitor, BHT, was purchased from Changzhou Kungen Composite Materials Co., Ltd.

[0023] The method for treating dehydrated toluene diisocyanate is as follows: heat the toluene diisocyanate in a clean three-necked flask to 115°C, and then filter it under reduced pressure after the thermometer reading stabilizes until no more bubbles are generated in the flask. Collect, seal and store for later use.

[0024] The method for processing dehydrated polypropylene glycol is as follows: Add polypropylene glycol to a clean, dry three-necked flask, install the vacuum device and thermometer, place it in an oil bath, turn on the heating and vacuum pump, maintain a stable vacuum, and slowly raise the temperature to 120°C. Dehydrate for 2 hours to obtain dehydrated polypropylene glycol, collect it in a container, seal it, and store it in a vacuum drying oven for later use.

[0025] (II) The preparation method of amino compounds is as follows: 550g of terminal amino polyether D-2000, 300g of T-5000, 100g of D-400, 42g of m-phenylenediamine, 1.4g of chain extender DETDA and 10g of defoamer BYK-168 are added sequentially to a three-necked flask, stirred evenly, heated and reacted for two hours, and then filtered under reduced pressure to remove water, thus obtaining the product.

[0026] Among them, the amino-terminated polyethers D-400, D-2000, and T-5000 were all purchased from Jinan Nuoshi New Materials Co., Ltd. The chain extender DETDA was purchased from Zhangjiagang Yarui Chemical Co., Ltd.

[0027] (III) High-performance rigid polyurea spraying process: Isocyanate component and amino compound are injected into the ISO and RES material storage tanks of the spraying machine respectively. After sealing the top cover of the ISO and RES material storage tanks, the main power of the spraying machine is turned on, and the material is circulated and heated to 85°C. The spray gun pressure of the spraying machine is set to 80Kpa. After the reading stabilizes for 10 minutes, the isocyanate component and amino compound react rapidly to form a film during the spraying process at a volume ratio of 1.1:1, and then the spraying is carried out.

[0028] Example 2 The difference between this embodiment and Embodiment 1 is that: in the high-performance rigid polyurea spraying process, the isocyanate component and amino compound are injected into the ISO and RES material storage tanks of the spraying machine, respectively. After the top covers of the ISO and RES material storage tanks are sealed, the main power of the spraying machine is turned on, and the material is circulated and heated to 85°C. The spray gun pressure of the spraying machine is set to 80 kPa. After the reading stabilizes for 10 minutes, the isocyanate component and amino compound react rapidly to form a film during the spraying process at a volume ratio of 1.08:1, and then the spraying is carried out.

[0029] Example 3 The difference between this embodiment and Embodiment 1 is that: in the high-performance rigid polyurea spraying process, the isocyanate component and amino compound are injected into the ISO and RES material storage tanks of the spraying machine, respectively. After the top covers of the ISO and RES material storage tanks are sealed, the main power of the spraying machine is turned on, and the material is circulated and heated to 85°C. The spray gun pressure of the spraying machine is set to 80 kPa. After the reading stabilizes for 10 minutes, the isocyanate component and amino compound react rapidly to form a film during the spraying process at a volume ratio of 1.12:1, and then the spraying is carried out.

[0030] Comparative Example 1 The difference between this comparative example and Example 1 is that glycerol is not added in the preparation of the isocyanate component, and m-phenylenediamine is not added in the preparation of the amino compound; and the isocyanate component and the amino compound are rapidly reacted to form a film during the spraying process at a volume ratio of 1.0:1 before spraying.

[0031] Comparative Example 2 The difference between this comparative example and Example 1 is that glycerol is not added in the preparation of the isocyanate component, and m-phenylenediamine is not added in the preparation of the amino compound.

[0032] Comparative Example 3 The difference between this comparative example and Example 1 is that the isocyanate component and the amino compound are rapidly reacted to form a film during the spraying process at a volume ratio of 1.0:1.

[0033] Test case Test subjects: Polyurea coatings from Examples 1-3 and Comparative Examples 1-3. Test items and methods: ① Shore hardness (D) - determined according to GB / T531-1992; ② Elongation at break (%) = (L1 / L0) × 100%; L1 is the length of the test subject sample strip at break, and L0 is the initial length of the test subject sample strip. Test results: see Table 1.

[0034] Table 1. Test Data for Experimental Examples

[0035] Results Analysis: Analysis of Examples 1-3, combined with data from Table 1 and... Figures 1-2 As can be seen, the polyurea coating of the present invention (Examples 1-3) has a Shore hardness of up to 123 (D) and an elongation at break of up to 126.2%.

[0036] Analyze Example 1 and Comparative Examples 1-3 and combine the data in Table 1 and Figures 1-2 Specifically, comparing Comparative Examples 1 and 2, it can be seen that compared to the volume ratio of isocyanate prepolymer to amino compound of 1.0:1 in Comparative Example 1, the volume ratio of isocyanate prepolymer to amino compound increased to 1.1:1 in Comparative Example 2. As a result, the Shore hardness of the polyurea coating decreased from 117 (Comparative Example 1) to 113 (Comparative Example 2), and the elongation at break decreased from 121.2% (Comparative Example 1) to 116.8% (Comparative Example 2). This indicates that increasing the volume ratio of isocyanate prepolymer to amino compound from 1.0:1 to 1.1:1 leads to a decrease in the Shore hardness and elongation at break of the polyurea coating.

[0037] This is mainly because polyurea synthesis is essentially a stepwise polymerization reaction between bifunctional groups (NCO + NH2 → urea bond). As the proportion of NCO increases, more urea bonds form a dense three-dimensional network, which enhances the rigidity of the material, i.e., increases the Shore hardness. Furthermore, more NCO can better promote the formation of linear prepolymers, extend the length of flexible segments, and maintain a reasonable effective crosslinking point spacing, which is beneficial to improving the elongation at break. However, if the amount of NCO increases to an excessive level, it will self-polymerize and undergo trimerization and ring formation, resulting in a decrease in Shore hardness and elongation at break.

[0038] Specifically, comparing Comparative Examples 1 and 3, it can be seen that compared to Comparative Example 1 (where the volume ratio of isocyanate prepolymer to amino compound was 1.0:1), Comparative Example 3, by introducing glycerol in the preparation of the isocyanate component and adding m-phenylenediamine in the preparation of the amino compound, resulted in an increase in the Shore hardness of the polyurea coating from 117 (Comparative Example 1) to 120 (Comparative Example 3), and a decrease in the elongation at break from 121.2% (Comparative Example 1) to 123.6% (Comparative Example 3). This indicates that introducing glycerol in the preparation of the isocyanate component and adding m-phenylenediamine in the preparation of the amino compound can improve the Shore hardness and elongation at break of the polyurea coating.

[0039] In comparison with Example 1, it can be seen that when the volume ratio of isocyanate prepolymer to amino compound is 1.1:1, the introduction of glycerol in the preparation of isocyanate component and the introduction of m-phenylenediamine in the preparation of amino compound can produce a synergistic effect, which can synergistically improve the Shore hardness and elongation at break of polyurea coating.

[0040] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0041] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A high-performance rigid polyurea spraying process, characterized in that, Inject the isocyanate component and amino compound into the ISO and RES material storage tanks of the spraying machine, respectively. After sealing the top covers of the ISO and RES material storage tanks, turn on the main power of the spraying machine to allow the material to circulate and heat to 85°C. Set the spray gun pressure of the spraying machine to 80 kPa. After the reading stabilizes for 10 minutes, allow the isocyanate component and amino compound to react rapidly to form a film during the spraying process at a volume ratio of (1.08-1.12):1, and then spray. The isocyanate component is prepared from toluene diisocyanate, polypropylene glycol, low molecular weight polyol, organic bismuth catalyst and polymerization inhibitor; the amino compound is prepared from amino-terminated polyether, aromatic diamine, chain extender and defoamer.

2. The high-performance rigid polyurea spraying process according to claim 1, characterized in that, The isocyanate component is prepared as follows: The initial temperature is 20°C. A clean three-necked flask is purged and dried with nitrogen for 2 minutes. Under nitrogen purging conditions, 355-365g of dehydrated toluene diisocyanate is added. Under mechanical stirring, the mixture is heated to 20°C. Then, 635-645g of dehydrated polypropylene glycol, 45-50g of low molecular weight polyol, 0.5-0.8g of organic bismuth catalyst, and 1.0-1.2g of polymerization inhibitor (BHT) are added. The vacuum degree is then stabilized at 0.09 MPa, and the temperature is continuously raised to 80°C for 2 hours. Finally, the mixture is dehydrated under reduced pressure until no more bubbles are generated, thus obtaining the final product.

3. The high-performance rigid polyurea spraying process according to claim 2, characterized in that, The method for treating the dehydrated toluene diisocyanate is as follows: heat the toluene diisocyanate in a clean three-necked flask to 115°C, and then filter it under reduced pressure after the thermometer reading stabilizes until no more bubbles are generated in the flask.

4. The high-performance rigid polyurea spraying process according to claim 2, characterized in that, The method for treating the dehydrated polypropylene glycol is as follows: add polypropylene glycol to a clean, dry three-necked flask, install the vacuum device and thermometer, place it in an oil bath, turn on the heating and vacuum pump, maintain a stable vacuum, and then raise the temperature to 120°C for 2 hours for dehydration.

5. The high-performance rigid polyurea spraying process according to claim 2, characterized in that, The low molecular weight polyols include glycerol or glycerol.

6. The high-performance rigid polyurea spraying process according to claim 2, characterized in that, The polymerization inhibitor is BHT.

7. The high-performance rigid polyurea spraying process according to claim 1, characterized in that, The preparation method of the amino compound is as follows: 950-1000g of terminal amino polyether, 40-45g of aromatic diamine, 1.4g of chain extender and 10g of defoamer are added sequentially to a three-necked flask, stirred evenly, heated and reacted for two hours, and then filtered and the water was removed under reduced pressure to obtain the final product.

8. The high-performance rigid polyurea spraying process according to claim 7, characterized in that, The terminal amino polyethers include D-2000, T-5000, and D-400.

9. The high-performance rigid polyurea spraying process according to claim 7, characterized in that, The chain extender is DETDA.

10. The high-performance rigid polyurea spraying process according to claim 7, characterized in that, The defoamer is BYK-168.

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