Preparation method of coating for pipeline concrete

Abstract

The invention belongs to the technical field of building materials, and discloses a preparation method of a coating for pipeline concrete, which comprises the following steps of: adding 28-36 parts by weight of modified epoxy resin and 4-8 parts by weight of polyurethane resin into 26-30 parts by weight of solvent, 11-15 parts by weight of filler, 0.5-1.5 parts by weight of wax powder, 1.1-1.5 parts by weight of flatting agent and 0.5-0.9 part by weight of dispersing agent, increasing the rotating speed to 600rpm, stirring for 10 minutes, increasing the rotating speed to 1000rpm, stirring for 10 minutes, and cooling to room temperature to obtain the coating for pipeline concrete. Finally, adding 8-16 parts of a curing agent, stirring for 20 minutes, and fully and uniformly mixing to obtain a coating; wherein the filler is prepared from the following components in parts by weight: 4 to 7 parts of modified nano silicon dioxide, 8 to 12 parts of modified silicon carbide and 1.5 to 4.5 parts of graphene. The coating prepared by the invention has high smoothness, strong corrosion resistance and wear resistance, and can be well applied to corrosion and wear resistance of the concrete surface of the pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a method for preparing a coating for pipeline concrete. Background Art

[0002] Concrete is often used in the process of road and bridge construction, pipeline laying, etc. In order to prevent concrete from being corroded, a protective layer is generally formed by spraying or brushing paint. However, some projects have specific requirements for the concrete surface, such as smoothness, corrosion resistance, wear resistance, etc., so the corresponding coating must meet the above requirements and have corresponding adhesion to ensure that the coating can be permanently and stably attached to the concrete surface. However, it is difficult for currently available coatings to simultaneously meet high smoothness, strong adhesion and excellent corrosion / wear resistance, so it is necessary to develop corresponding coatings to meet market demand. Summary of the invention

[0003] The first technical problem to be solved by the present invention is to provide a method for preparing a coating for pipeline concrete. The coating prepared by this method has high smoothness, strong corrosion resistance and wear resistance, and can be well applied to the corrosion and wear protection of pipeline concrete surface.

[0004] In order to solve the above technical problems, the technical solution of the present invention is:

[0005] A method for preparing a coating for pipeline concrete comprises the following steps: adding, by weight, 28 to 36 parts of modified epoxy resin and 4 to 8 parts of polyurethane resin to 26 to 30 parts of solvent, 11 to 15 parts of filler, 0.5 to 1.5 parts of wax powder (PE wax), 1.1 to 1.5 parts of leveling agent and 0.5 to 0.9 parts of dispersant; after all are added, the rotation speed is increased to 600 rpm, stirred for 10 minutes, then increased to 1000 rpm and stirred for 10 minutes, and finally 8 to 16 parts of curing agent are added, stirred for 20 minutes, and fully mixed to prepare the coating; wherein the filler is composed of the following components by weight: 4 to 7 parts of modified nano silicon dioxide, 8 to 12 parts of modified silicon carbide and 1.5 to 4.5 parts of graphene.

[0006] Preferably, the weight parts of the modified epoxy resin are 32 parts, the weight parts of the polyurethane resin are 6 parts, the weight parts of the solvent are 28 parts, the weight parts of the filler are 13 parts, the weight parts of the curing agent are 17 parts, the weight parts of the wax powder (PE wax) are 1 part, the weight parts of the leveling agent are 1.3 parts, and the weight parts of the dispersant are 0.7 parts; wherein the filler is composed of the following components in weight parts: 5.5 parts of modified nano-silicon dioxide, 10 parts of modified silicon carbide, and 3.0 parts of graphene.

[0007] Preferably, the modified epoxy resin is modified epoxy resin DER331; the polyurethane resin is polyurethane resin DP 2590A; the solvent is toluene; the wax powder is wax powder PE(H)-100; the leveling agent is leveling agent BD-3376; the dispersant is dispersant SDJ8005; and the curing agent is isophorone diisocyanate.

[0008] Preferably, the modified nano-silica is nano-silica modified with a silane coupling agent (KH-550), and the specific modification steps are: 1. First, the nano-silica is placed at 100-120° C. and dried for 2-4 hours to remove the moisture adsorbed on the surface, and then the nano-silica is dispersed in anhydrous ethanol at a ratio of 5-10wt%, and ultrasonically treated (power 300-500W) for 30-60 minutes; 2. The silane coupling agent (KH-550) is dissolved in an ethanol / water mixed solvent (ethanol: water = 95:5, volume ratio) at a ratio of 1-5%, and the pH is adjusted to 4-5 with acetic acid, and stirred. 3. Add the hydrolyzed silane solution to the nano-silica dispersion, the mass ratio of silica to silane is about 1:0.1-0.5, reflux reaction at 70-80°C for 6-12 hours, and continuously stir at 2000rpm to condense the silane with the hydroxyl groups on the surface of the silica (forming Si-O-Si bonds); 4. After the reaction is completed, collect the modified silica by centrifugation or filtration, wash with ethanol for multiple times to remove the unreacted silane, and vacuum dry at 60-80°C for 6-12 hours to obtain the modified nano-silica.

[0009] Furthermore, the nano-silica was dried at 110° C. for 3 hours, then dispersed in anhydrous ethanol at a ratio of 7.5 wt%, and ultrasonically treated (power 400 W) for 45 minutes; a silane coupling agent (KH-550) was dissolved in an ethanol / water mixed solvent at a ratio of 3%, the pH was adjusted to 4.5 with acetic acid, and stirred for 45 minutes; the mass ratio of silica to silane was about 1:0.3, and the mixture was refluxed at 75° C. for 9 hours; and vacuum dried at 70° C. for 9 hours.

[0010] Preferably, the modified silicon carbide is laser surface modified silicon carbide; the surface of silicon carbide is scanned by laser under nitrogen protection, and the specific process parameters are: laser power 1kW, spot diameter 1mm, scanning speed 10mm / s, pulse frequency 50kHz; after laser scanning, it is rapidly cooled at 4°C to obtain modified silicon carbide.

[0011] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0012] The invention significantly improves the anti-corrosion and anti-wear properties of the coating by modifying the nano-silicon dioxide and silicon carbide in the filler, wherein the nano-silicon dioxide is introduced into the amino group (-NH 2), which not only increases the wear resistance of silica, but also effectively enhances the compatibility of silica with modified epoxy resin; the surface modification of silicon carbide by laser can effectively increase its hardness, wear resistance and oxidation resistance; the addition of PE wax reduces the friction coefficient of the coating and improves the surface smoothness, meeting the requirements of concrete surface smoothness for specific needs.

[0013] In conclusion, the coating prepared by the method of the present invention has high smoothness, strong corrosion resistance and wear resistance, and can be well applied to coating the surface of pipeline concrete. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further described below in conjunction with embodiments:

[0015] Example 1: Preparation of filler

[0016] 1. Preparation of modified nano-silica: a. First, the nano-silica was dried at 110°C for 3 hours to remove the moisture adsorbed on the surface, and then the nano-silica was dispersed in anhydrous ethanol at a ratio of 7.5wt% and ultrasonically treated (power 400W) for 45 minutes; b. The silane coupling agent (KH-550) was dissolved in an ethanol / water mixed solvent (ethanol: water = 95:5, volume ratio) at a ratio of 3%, and the pH was adjusted to 4.5 with acetic acid, and stirred for 45 minutes to promote the hydrolysis of silane to generate silanol (Si-OH); c. adding the hydrolyzed silane solution to the nano-silica dispersion, the mass ratio of silica to silane is about 1:0.3, and reflux reaction is carried out at 75°C for 9 hours, and continuous stirring is carried out at 2000rpm to condense the silane with the hydroxyl groups on the surface of the silica (forming Si-O-Si bonds); d. after the reaction is completed, the modified silica is collected by centrifugation or filtration, washed with ethanol several times to remove the unreacted silane, and vacuum dried at 70°C for 9 hours to obtain the modified nano-silica;

[0017] 2. Preparation of modified silicon carbide: The surface of silicon carbide was scanned by laser under nitrogen protection. The specific process parameters were: laser power 1kW, spot diameter 1mm, scanning speed 10mm / s, pulse frequency 50kHz; after laser scanning, it was rapidly cooled at 4°C to obtain modified silicon carbide;

[0018] 3. The modified nano-silicon dioxide obtained in step 1, the modified silicon carbide obtained in step 2 and graphene are fully mixed in a weight ratio of 5.5:10:3.0 to obtain a filler.

[0019] Example 2 Preparation of coating

[0020] Add 26 kg of toluene to the reactor, stir at 300 rpm, then add 28 kg of modified epoxy resin DER331, 8 kg of polyurethane resin DP 2590A, 11 kg of the filler prepared in Example 1, 1.5 kg of wax powder PE(H)-100, 1.1 kg of leveling agent BD-3376 and 0.9 kg of dispersant SDJ8005 were all added and the speed was increased to 600 rpm and stirred for 10 minutes, then increased to 1000 rpm and stirred for 10 minutes, and finally 16 kg of isophorone diisocyanate was added. After the addition was completed, the stirring speed was increased to 1000 rpm and stirred for 20 minutes, and the absorbing coating was obtained after sufficient mixing.

[0021] Example 3 Preparation of coating 2

[0022] Add 30 kg of toluene to the reactor, stir at 300 rpm, then add 36 kg of modified epoxy resin DER331, 4 kg of polyurethane resin DP 2590A, 15 kg of the filler prepared in Example 1, 0.5 kg of wax powder PE(H)-100, 1.5 kg of leveling agent BD-3376 and 0.5 kg of dispersant SDJ8005 were all added and the speed was increased to 600 rpm and stirred for 10 minutes, then increased to 1000 rpm and stirred for 10 minutes, and finally 8 kg of isophorone diisocyanate was added. After the addition was completed, the stirring speed was increased to 1000 rpm and stirred for 20 minutes, and the absorbing coating was obtained after sufficient mixing.

[0023] Example 4 Preparation of coating 3

[0024] Add 28 kg of toluene to the reactor, stir at 300 rpm, then add 32 kg of modified epoxy resin DER331, 6 kg of polyurethane resin DP 2590A, 13 kg of the filler prepared in Example 1, 1 kg of wax powder PE(H)-100, 1.3 kg of leveling agent BD-3376 and 0.7 kg of dispersant SDJ8005 were all added, the speed was increased to 600 rpm, stirred for 10 minutes, then increased to 1000 rpm and stirred for 10 minutes, and finally 12 kg of isophorone diisocyanate was added. After the addition was completed, the stirring speed was increased to 1000 rpm and stirred for 20 minutes. The absorbing coating was obtained by fully mixing.

[0025] Comparative Example 1

[0026] In the filler of Example 4, ordinary nano-silica is used instead of modified nano-silica, and the rest is the same as Example 4.

[0027] Comparative Example 2

[0028] In the filler of Example 4, unmodified silicon carbide is used instead of modified silicon carbide, and the rest is the same as Example 4.

[0029] Comparative Example 3

[0030] In the filler of Example 4, ordinary nano-silicon dioxide is used instead of modified nano-silicon dioxide, and unmodified silicon carbide is used instead of modified silicon carbide. The rest is the same as Example 4.

[0031] The coatings obtained in Examples 2-4 and Comparative Examples 1-3 were sprayed onto an aluminum plate to prepare a 2 mm thick coating, and cured at 25° C. for 7 days to obtain a coating. The coating was then subjected to a performance test. The test results are shown in Table 1. The test standards are:

[0032] Smoothness: visual and tactile inspection, according to ISO 8503-2 standard;

[0033] Adhesion: in accordance with the provisions of 9.4.3 of GB / T5210-2006;

[0034] Wear resistance: in accordance with the provisions of GB / T1768-2006;

[0035] Corrosion resistance: in accordance with the provisions of GB / T31588.1-2015.

[0036] Table 1 Test results of coatings prepared in Examples 2-4 and Comparative Examples 1-3

[0037] Smoothness Adhesion(MPa) Wear weight loss (g) Salt spray resistance(h) Example 2 A-level 8.1 0.0631 3248 Example 3 A-level 8.3 0.0610 3254 Example 4 A-level 8.5 0.0527 3300 Comparative Example 1 A-level 6.7 0.1098 2953 Comparative Example 2 A-level 6.6 0.1134 2944 Comparative Example 3 A-level 6.1 0.1357 2785

[0038] As can be seen from Table 1, the formula of Example 4 (32 parts of modified epoxy resin, 6 parts of polyurethane resin, 13 parts of filler, 17 parts of curing agent, 1 part of wax powder, 1.3 parts of leveling agent, and 0.7 parts of dispersant) has the best comprehensive performance, and its adhesion, abrasion weight loss and salt spray resistance results are the best.

[0039] The components in the fillers of Comparative Examples 1 to 3 used non-modified raw materials as controls. It can be seen that the unmodified raw materials significantly affected the adhesion, abrasion weight loss and salt spray resistance results of the final products.

[0040] Through the above experiments, it can be seen that modified nano-silicon dioxide and modified silicon carbide can significantly improve the adhesion, wear resistance and corrosion resistance of the coating. The prepared products can be used for surface coating of pipeline concrete. At the same time, because the addition of wax powder increases the smoothness of the coating, it can meet the needs of pipeline concrete with specific requirements.

[0041] It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A method for preparing a coating for pipeline concrete, characterized in that: By weight, 28 to 36 parts of modified epoxy resin and 4 to 8 parts of polyurethane resin are added to 26 to 30 parts of solvent, 11 to 15 parts of filler, 0.5 to 1.5 parts of wax powder, 1.1 to 1.5 parts of leveling agent and 0.5 to 0.9 parts of dispersant. After all are added, the speed is increased to 600 rpm, stirred for 10 minutes, then increased to 1000 rpm and stirred for 10 minutes, and finally 8 to 16 parts of curing agent are added, stirred for 20 minutes, and fully mixed to prepare a coating; The filler is composed of the following components in parts by weight: 4 to 7 parts of modified nano silicon dioxide, 8 to 12 parts of modified silicon carbide, and 1.5 to 4.5 parts of graphene.

2. The method for preparing the coating for pipeline concrete according to claim 1, characterized in that: The weight parts of the modified epoxy resin are 32 parts, the weight parts of the polyurethane resin are 6 parts, the weight parts of the solvent are 28 parts, the weight parts of the filler are 13 parts, the weight parts of the curing agent are 17 parts, the weight parts of the wax powder are 1 part, the weight parts of the leveling agent are 1.3 parts, and the weight parts of the dispersant are 0.7 parts; The filler is composed of the following components in parts by weight: 5.5 parts of modified nano-silicon dioxide, 10 parts of modified silicon carbide, and 3.0 parts of graphene.

3. The method for preparing the coating for pipeline concrete according to claim 1, characterized in that: The modified nano-silica is nano-silica modified by silane coupling agent KH-550, and the specific modification steps are:

1. First, the nano-silica is placed at 100-120° C. and dried for 2-4 hours, and then the nano-silica is dispersed in anhydrous ethanol at a ratio of 5-10wt% and ultrasonically treated for 30-60 minutes; 2. The silane coupling agent KH-550 is dissolved in an ethanol / water mixed solvent at a volume ratio of 1-5%, and the pH is adjusted to 4-5 with acetic acid, and stirred for 30-60 minutes.

3. Add the hydrolyzed silane solution to the nano-silica dispersion, the mass ratio of silica to silane is about 1:0.1-0.5, reflux reaction at 70-80°C for 6-12 hours, and continuously stir at 2000rpm to condense the silane with the hydroxyl groups on the surface of the silica; 4. After the reaction is completed, collect the modified silica by centrifugation or filtration, wash with ethanol several times to remove the unreacted silane, and vacuum dry at 60-80°C for 6-12 hours to obtain the modified nano-silica.

4. The method for preparing the coating for pipeline concrete according to claim 3, characterized in that: The nano silicon dioxide is placed at 110° C. and dried for 3 hours, then dispersed in anhydrous ethanol at a ratio of 7.5wt% and ultrasonically treated for 45 minutes; the silane coupling agent KH-550 is dissolved in an ethanol / water mixed solvent at a volume ratio of 3%, the pH is adjusted to 4.5 with acetic acid, and stirred for 45 minutes; the mass ratio of silicon dioxide to silane is about 1:0.3, and reflux reaction is carried out at 75° C. for 9 hours; and vacuum drying is carried out at 70° C. for 9 hours.

5. The method for preparing the coating for pipeline concrete according to claim 1, characterized in that: The modified silicon carbide is laser surface modified silicon carbide; the surface of silicon carbide is scanned by laser under nitrogen protection, and the specific process parameters are: laser power 1kW, spot diameter 1mm, scanning speed 10mm / s, pulse frequency 50kHz; after laser scanning, it is quickly cooled in an environment of 4°C to obtain modified silicon carbide.