Aging-resistant superabsorbent coating material and preparation method thereof

Abstract

The application provides an anti-aging high water-absorbing coating material and a preparation method thereof, and components for preparing the anti-aging high water-absorbing coating material include, by weight, 2-5 parts of modified sodium polyacrylate resin, 0.8-1.5 parts of benzene propyl triazole, 5-15 parts of a humectant, 30-50 parts of a filler, 10-15 parts of a binder, 0.02-0.1 parts of a preservative, and 20-40 parts of water; the anti-aging high water-absorbing coating material can adapt to temperature changes of a working environment, keep stable performance, and has good chemical corrosion resistance, high water-absorbing property and adhesion.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to an aging-resistant, highly absorbent coating material and its preparation method. Background Technology

[0002] In today's construction, industrial, and various infrastructure sectors, the sealing of piping systems is of paramount importance. Threaded connections, as a widely used pipe connection method, directly affect the normal operation, safety, and service life of the system through their sealing performance. Aging-resistant, highly absorbent coating materials have emerged to address these challenges, aiming to solve many problems exhibited by traditional sealing materials in complex working environments.

[0003] PTFE tape is a common threaded sealing material, primarily composed of polytetrafluoroethylene (PTFE). While PTFE possesses good chemical stability and a low coefficient of friction, PTFE tape exhibits poor aging resistance. Over long-term use, exposed to factors such as ultraviolet radiation and temperature changes, PTFE tape gradually becomes brittle and ages, leading to a decline in sealing performance. Furthermore, PTFE tape has virtually zero water absorption, rendering it ineffective in humid environments. Its adhesion is also relatively weak, making it prone to detaching from pipe threads under significant external force, resulting in seal failure. Some sealants can meet adhesion requirements to a certain extent, but their aging resistance is limited. In harsh environments such as high temperature and high humidity, sealants are prone to aging and cracking, thus losing their sealing function. Some sealants also have unsatisfactory chemical corrosion resistance; they can be corroded and dissolved upon contact with corrosive media, compromising seal reliability. In addition, the curing process of sealants can be affected by environmental temperature and humidity, leading to incomplete curing or excessively long curing times, impacting construction efficiency and sealing effectiveness. Rubber seals possess a certain degree of elasticity and sealing performance, but they exhibit significant shortcomings in aging resistance. Rubber is easily affected by factors such as oxygen, ultraviolet radiation, and temperature, leading to aging, hardening, loss of elasticity, and decreased sealing performance. In high-temperature environments, rubber seals may also soften and deform. For media with special chemical properties, the chemical corrosion resistance of rubber seals is insufficient, making them susceptible to erosion and damage. Furthermore, rubber seals require high dimensional accuracy during installation; improper installation can easily result in incomplete sealing.

[0004] In fire protection systems, the ambient temperature around pipes can rise sharply during a fire, reaching hundreds of degrees Celsius or even higher, while under normal conditions the ambient temperature is relatively low. This significant temperature fluctuation places extremely high demands on the performance stability of sealing materials. Sometimes, fire extinguishing agents containing chemicals are used, which may be corrosive. Over long-term use, the interface between the sealing material and the surrounding chemical substances can still be eroded by these substances. In humid environments, the presence of moisture in piping systems can affect the sealing effect. In this case, highly absorbent sealing materials can absorb surrounding moisture, preventing moisture accumulation at the seal and reducing corrosion and seal failure caused by moisture. For threaded pipe seals, good adhesion ensures a tight fit between the sealing material and the pipe threads, forming a strong sealing layer. During the operation of a piping system, it is subjected to various external forces, such as vibration and pressure fluctuations. If the sealing material has poor adhesion, it is prone to separating from the pipe under these external forces, leading to seal failure. In fire protection systems, the vibrations and water hammer effects during a fire can generate significant external impacts on the sealing areas. During operation, the impact of water flow and slight vibrations in pipes can test the adhesion performance of sealing materials in hydronic and underfloor heating systems. Therefore, sealing materials with good adhesion are crucial for ensuring the reliability of the piping system's seal.

[0005] In summary, developing a coating material that can adapt to temperature changes in the working environment, maintain stable performance, and possess good chemical corrosion resistance, high water absorption, and adhesion is a problem that this invention urgently needs to solve. Summary of the Invention

[0006] Purpose of the invention:

[0007] To address the shortcomings of existing technologies, this invention provides an aging-resistant, highly absorbent coating material and its preparation method, which can adapt to temperature changes in the working environment, maintain stable performance, and exhibits good chemical corrosion resistance, high water absorption, and adhesion.

[0008] The technical solution of this invention:

[0009] This invention provides an aging-resistant, highly absorbent coating material. The components used to prepare the aging-resistant, highly absorbent coating material, by weight, include: 2-5 parts modified sodium polyacrylate resin, 0.8-1.5 parts benzotriazole, 5-15 parts humectant, 30-50 parts filler, 10-15 parts binder, 0.02-0.1 parts preservative, and 20-40 parts water.

[0010] Furthermore, the modified sodium polyacrylate resin is prepared by reacting hydroxyethyl acrylate, attapulgite, acrylic acid, ammonium bicarbonate, and ethylene glycol diglycidyl ether.

[0011] The preparation method of the modified sodium polyacrylate resin includes the following steps:

[0012] S1: Add attapulgite to a 2-4 mol / L hydrochloric acid solution, stir at 60-80℃ for 2-4 hours, then wash with deionized water until the pH value is 7-8, disperse in an appropriate amount of deionized water to obtain an attapulgite dispersion, and dilute the acrylic acid to an acrylic acid solution using a sodium hydroxide solution with a volume concentration of 20-30%.

[0013] S2: In step S1, hydroxyethyl acrylate and potassium persulfate are added to the attapulgite dispersion, nitrogen gas is introduced, stirring is started, the temperature is raised to 60-80℃, and after reacting for 2-4 hours, the mixture is cooled, poured into anhydrous ethanol for precipitation, and filtered to obtain the hydroxyethyl acrylate-attapulgite product.

[0014] S3: Pour the hydroxyethyl acrylate-attapulgite product obtained in step S2 into a medium acrylic acid solution, add N,N-methylenebisacrylamide and ammonium bicarbonate, purge with nitrogen, start stirring, heat to 60-80℃, and react for 1-3 hours. Then, lower the temperature of the reaction system to 40-55℃, slowly add ethylene glycol diglycidyl ether dropwise, and continue stirring for 2-4 hours after the addition is complete. After the reaction is complete, cool the reaction product to room temperature, pour it into anhydrous ethanol for precipitation, filter, and dry to obtain modified sodium polyacrylate resin.

[0015] Furthermore, the mass ratio of hydroxyethyl acrylate to attapulgite is 2-3:1; the mass ratio of the hydroxyethyl acrylate-attapulgite product, acrylic acid, and ethylene glycol diglycidyl ether is 2-4:1-2:0.5-1.

[0016] Furthermore, the mass concentration of the acrylic acid solution is 60-80%; the amount of potassium persulfate added is 0.5-2% of the mass of hydroxyethyl acrylate; the amount of N,N-methylenebisacrylamide added is 0.2-1% of the mass of acrylic acid; and the amount of ammonium bicarbonate added is 0.8-1.5% of the mass of acrylic acid.

[0017] Furthermore, the moisturizer is one or a mixture of glycerin, propylene glycol, and sorbitol.

[0018] Furthermore, the filler is one or more of mica powder, bentonite, and calcium carbonate.

[0019] Furthermore, the binder is one or more of pregelatinized starch, potassium silicate, and gelatin.

[0020] Furthermore, the preservative is one or a mixture of Kathon, benzisothiazolinone, and methylisothiazolinone.

[0021] This invention also provides a method for preparing an aging-resistant, highly absorbent coating material, comprising the following steps:

[0022] Step 1: Add the adhesive to water and stir to dissolve. Then add benzotriazole, humectant, and preservative, and stir evenly to obtain the mixed excipient.

[0023] Step 2: Slowly add the filler to the mixed excipients prepared in Step 1, and mix at a stirring speed of 300-450 rpm and 100-120℃ for 10-15 minutes to obtain the mixture.

[0024] Step 3: Finally, add modified sodium polyacrylate resin to the mixture prepared in step 2, and mix at a stirring speed of 300-450 rpm and a temperature of 100-120°C for 2-5 minutes to obtain an aging-resistant, highly absorbent coating material.

[0025] The aging-resistant, highly absorbent coating material of this invention is prepared using physical and chemical methods. Hydroxyethyl acrylate is combined with attapulgite to form a highly absorbent resin structure, which then polymerizes with acrylic acid to form hydrogen bonds, improving water absorption, chemical corrosion resistance, and adhesion. Ethylene glycol diglycidyl ether is used for activation treatment, resulting in a modified sodium polyacrylate resin that is resistant to high and low temperatures, chemical corrosion, and exhibits strong water absorption and adhesion. This modified sodium polyacrylate resin is combined with various fillers and additives to form a composite material. The prepared aging-resistant, highly absorbent coating material can adapt to temperature changes in the working environment, maintain stable performance, and exhibits good chemical corrosion resistance, high water absorption, and adhesion.

[0026] Beneficial effects:

[0027] The aging-resistant, highly absorbent coating material of this invention can adapt to temperature changes in the working environment, maintain stable performance, and exhibits good chemical corrosion resistance, high water absorption, and adhesion. Detailed Implementation

[0028] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0029] In the following preparation examples, embodiments, and comparative examples, attapulgite was purchased from Hebei Hezhen Industrial Co., Ltd.; pregelatinized starch was purchased from Ningjin Jiahe Energy-Saving Materials Co., Ltd.; potassium silicate (potassium water glass) was purchased from Shandong Baite New Materials Co., Ltd.; potassium-type silica sol, mica powder, and calcium carbonate were 1000 mesh; bentonite was sodium-based bentonite, purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd., 1250 mesh, whiteness 90%, and moisture content 1.2%; and Kathon was purchased from Qingdao Xiangze Chemical Co., Ltd.

[0030] Unless otherwise specified, all other chemical reagents used in this invention are commercially available analytical grade reagents.

[0031] Preparation of modified sodium polyacrylate resin A:

[0032] S1: Add 10g of attapulgite to 500mL of 2mol / L hydrochloric acid solution, stir at 60℃ for 2 hours, then wash with deionized water until pH value 7, disperse in 500mL of deionized water to obtain attapulgite dispersion, and use 20% sodium hydroxide solution to dilute 10g of acrylic acid to 60% acrylic acid solution.

[0033] S2: In step S1, 20g of hydroxyethyl acrylate and 0.2g of potassium persulfate were added to the attapulgite dispersion. Nitrogen gas was introduced, stirring was started, and the temperature was raised to 75°C. After reacting for 3 hours, the mixture was cooled and poured into anhydrous ethanol to precipitate and filtered to obtain the hydroxyethyl acrylate-attapulgite product.

[0034] S3: Pour the hydroxyethyl acrylate-attapulgite product obtained in step S2 into a medium acrylic acid solution, add 0.05g N,N-methylenebisacrylamide and 0.1g ammonium bicarbonate, purge with nitrogen, start stirring, heat to 75℃, and react for 2 hours. Then, lower the temperature of the reaction system to 45℃ and slowly add 10g ethylene glycol diglycidyl ether. After the addition is complete, continue stirring for 3 hours. After the reaction is complete, cool the reaction product to room temperature, pour it into anhydrous ethanol to precipitate, filter, and dry to obtain modified sodium polyacrylate resin A.

[0035] Preparation of modified sodium polyacrylate resin B:

[0036] The difference from modified sodium polyacrylate resin A is as follows: in step S1, 10g of acrylic acid is replaced with 20g of acrylic acid; in step S2, 20g of hydroxyethyl acrylate and 0.2g of potassium persulfate are replaced with 30g of hydroxyethyl acrylate and 0.3g of potassium persulfate; in step S3, 0.05g of N,N-methylenebisacrylamide, 0.1g of ammonium bicarbonate, and 10g of ethylene glycol diglycidyl ether are replaced with 0.1g of N,N-methylenebisacrylamide, 0.2g of ammonium bicarbonate, and 5g of ethylene glycol diglycidyl ether.

[0037] Preparation of modified sodium polyacrylate resin C:

[0038] The difference from modified sodium polyacrylate resin A is that in step S1, 10g of acrylic acid is replaced with 5g of acrylic acid.

[0039] Preparation of modified sodium polyacrylate resin D:

[0040] The difference from modified sodium polyacrylate resin A is that in step S1, 10g of attapulgite is replaced with 20g of attapulgite.

[0041] A method for preparing an aging-resistant, highly absorbent coating material includes the following steps:

[0042] Step 1: Add the adhesive to water and stir to dissolve. Then add benzotriazole, humectant, and preservative, and stir evenly to obtain the mixed excipient.

[0043] Step 2: Slowly add the filler to the mixed excipients prepared in Step 1, and mix at 100°C for 10 minutes with a stirring speed of 350 rpm to obtain the mixture.

[0044] Step 3: Finally, add modified sodium polyacrylate resin to the mixture prepared in step 2, and mix at 350 rpm and 100°C for 2 minutes to obtain an aging-resistant, highly absorbent coating material.

[0045] According to the above-described method for preparing aging-resistant and highly absorbent coating materials, the following examples and comparative examples use materials prepared in parts by weight for aging-resistant and highly absorbent coating materials.

[0046] Example 1

[0047] Step 1: Add 5g of pregelatinized starch and 6.5g of potassium silicate to 30g of water and stir to dissolve. Then add 1g of benzotriazole, 8g of glycerol and 0.05g of Kathon, and stir evenly to obtain the mixed excipient.

[0048] Step 2: Slowly add 20g mica powder, 20g bentonite, and 3.6g calcium carbonate to the mixed excipients prepared in Step 1, and mix at 100°C for 10 minutes with a stirring speed of 350 rpm to obtain the mixture.

[0049] Step 3: Finally, add 5g of modified sodium polyacrylate resin A to the mixture prepared in step 2, and mix at 350 rpm and 100°C for 2 minutes to obtain an aging-resistant, highly absorbent coating material.

[0050] Example 2

[0051] The difference between this preparation example and Example 1 is that in step one, 5g pregelatinized starch, 6.5g potassium silicate, 30g water, 1g benzotriazole, 8g glycerol, and 0.05g Kathon are replaced with 7g pregelatinized starch, 5g potassium silicate, 40g water, 0.8g benzotriazole, 5g glycerol, 5g sorbitol, 0.03g Kathon, and 0.05g benzisothiazolinone.

[0052] Example 3

[0053] The difference between this preparation example and Example 1 is that the modified sodium polyacrylate resin A in step three is replaced with modified sodium polyacrylate resin B.

[0054] Example 4

[0055] The difference between this preparation example and Example 1 is that the modified sodium polyacrylate resin A in step three is replaced with modified sodium polyacrylate resin C.

[0056] Example 5

[0057] The difference between this preparation example and Example 1 is that the modified sodium polyacrylate resin A in step three is replaced with modified sodium polyacrylate resin D.

[0058] Comparative Example 1

[0059] The difference between this preparation example and Example 1 is that the modified sodium polyacrylate resin A in step three is replaced with sodium acrylate resin.

[0060] Comparative Example 2

[0061] The difference between this preparation example and Example 1 is that the modified sodium polyacrylate resin A in step three is replaced with polytetrafluoroethylene.

[0062] The aging-resistant, highly absorbent coating materials prepared in each embodiment and comparative example were coated onto a 10×10cm nonwoven fabric with a coating thickness of 0.1mm. Then, they were heated and baked at 100℃ to obtain composite materials. The following tests were conducted, and the test results are shown in Table 1.

[0063] Performance testing:

[0064] 1. High and low temperature adaptability test: The test is conducted according to the standard GB / T 2423-2008 "Environmental Tests for Electrical and Electronic Products". The sample is kept at a low temperature of -40℃ for 24 hours, and then kept at a high temperature of 250℃ for 24 hours. This cycle is repeated 5 times. The sample is then observed to see if cracking, peeling, or deformation occurs.

[0065] 2. Water absorption test: The water absorption rate after 24 hours is tested according to the standard GB / T 1034-2008 "Determination of water absorption of plastics".

[0066] 3. Adhesion test: The tensile bond strength of paints and varnishes was tested according to the standard GB / T 5210-2006 "Paints and Varnishes - Pull-off Adhesion Test".

[0067] 4. Chemical resistance test: The test was conducted according to standard GB / T 1763-1979 "Test Method for Chemical Resistance of Coating Film", and the tensile bond strength after immersion was tested.

[0068] Test Results Table 1

[0069]

[0070] As can be seen from Table 1, the aging-resistant superabsorbent coating materials prepared in Examples 1-3 exhibit excellent high and low temperature adaptability, chemical corrosion resistance, superabsorbency, and adhesion. A comparison between Example 4 and Example 1 shows that reducing the amount of acrylic acid added during the preparation of the modified sodium polyacrylate resin weakens the high and low temperature adaptability, chemical corrosion resistance, water absorption, and adhesion of the prepared aging-resistant superabsorbent coating material, thus failing to achieve the expected results. A comparison between Example 5 and Example 1 shows that increasing the amount of attapulgite added during the preparation of the modified sodium polyacrylate resin leads to a decrease in the amount of attapulgite added, resulting in a decrease in the prepared aging-resistant superabsorbent coating material. The chemical corrosion resistance and water absorption of the coating material are reduced, failing to achieve the expected results. A comparison between Comparative Example 1 and Example 1 shows that replacing modified sodium polyacrylate resin A with sodium acrylate resin weakens the high and low temperature adaptability, chemical corrosion resistance, water absorption, and adhesion of the prepared aging-resistant, highly absorbent coating material, resulting in a failure to achieve the expected results. Similarly, a comparison between Comparative Example 2 and Example 1 shows that replacing modified sodium polyacrylate resin A with polytetrafluoroethylene (PTFE) weakens the high and low temperature adaptability, chemical corrosion resistance, water absorption, and adhesion of the prepared aging-resistant, highly absorbent coating material, resulting in a failure to achieve the expected results.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aging-resistant, highly absorbent coating material, characterized in that, The components for preparing the aging-resistant, highly absorbent coating material, by weight, include: 2-5 parts modified sodium polyacrylate resin, 0.8-1.5 parts benzotriazole, 5-15 parts humectant, 30-50 parts filler, 10-15 parts binder, 0.02-0.1 parts preservative, and 20-40 parts water; The modified sodium polyacrylate resin is prepared by reacting hydroxyethyl acrylate, attapulgite, acrylic acid, ammonium bicarbonate, and ethylene glycol diglycidyl ether; the preparation method of the modified sodium polyacrylate resin includes the following steps: S1: Add attapulgite to a 2-4 mol / L hydrochloric acid solution, stir at 60-80℃ for 2-4 hours, then wash with deionized water until the pH value is 7-8, disperse in an appropriate amount of deionized water to obtain an attapulgite dispersion, and dilute the acrylic acid to an acrylic acid solution using a 20-30% sodium hydroxide solution. S2: In step S1, hydroxyethyl acrylate and potassium persulfate are added to the attapulgite dispersion, nitrogen gas is introduced, stirring is started, the temperature is raised to 60-80℃, and after reacting for 2-4 hours, the mixture is cooled, poured into anhydrous ethanol for precipitation, and filtered to obtain the hydroxyethyl acrylate-attapulgite product. S3: Pour the hydroxyethyl acrylate-attapulgite product obtained in step S2 into a medium acrylic acid solution, add N,N-methylenebisacrylamide and ammonium bicarbonate, purge with nitrogen, start stirring, heat to 60-80℃, and react for 1-3 hours. Then, lower the temperature of the reaction system to 40-55℃, slowly add ethylene glycol diglycidyl ether dropwise, and continue stirring for 2-4 hours after the addition is complete. After the reaction is complete, cool the reaction product to room temperature, pour it into anhydrous ethanol for precipitation, filter, and dry to obtain modified sodium polyacrylate resin.

2. The aging-resistant, highly absorbent coating material according to claim 1, characterized in that, The mass ratio of hydroxyethyl acrylate to attapulgite is 2-3:1; the mass ratio of the hydroxyethyl acrylate-attapulgite product, acrylic acid, and ethylene glycol diglycidyl ether is 2-4:1-2:0.5-1.

3. The aging-resistant, highly absorbent coating material according to claim 1, characterized in that, The mass concentration of the acrylic acid solution is 60-80%; the amount of potassium persulfate added is 0.5-2% of the mass of hydroxyethyl acrylate; the amount of N,N-methylenebisacrylamide added is 0.2-1% of the mass of acrylic acid; and the amount of ammonium bicarbonate added is 0.8-1.5% of the mass of acrylic acid.

4. The aging-resistant, highly absorbent coating material according to claim 1, characterized in that, The moisturizer is one or a mixture of glycerin, propylene glycol, and sorbitol.

5. The aging-resistant, highly absorbent coating material according to claim 1, characterized in that, The filler is one or a mixture of mica powder, bentonite, and calcium carbonate.

6. The aging-resistant, highly absorbent coating material according to claim 1, characterized in that, The binder is one or more of pregelatinized starch and potassium silicate.

7. A method for preparing an aging-resistant, highly absorbent coating material according to any one of claims 1-6, comprising the following steps: Step 1: Add the adhesive to water and stir to dissolve. Then add benzotriazole, humectant, and preservative, and stir evenly to obtain the mixed excipient. Step 2: Slowly add the filler to the mixed excipients prepared in Step 1, and mix at a stirring speed of 300-450 rpm and 100-120℃ for 10-15 minutes to obtain the mixture. Step 3: Finally, add modified sodium polyacrylate resin to the mixture prepared in step 2, and mix at a stirring speed of 300-450 rpm and a temperature of 100-120°C for 2-5 minutes to obtain an aging-resistant, highly absorbent coating material.

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