BE1029988A1 - Insulation of the surface of a steel structure and anti-corrosion coating and its preparation method - Google Patents

Abstract

The present invention belongs to the technical field of the protection of steel structures and discloses a surface insulation and anti-corrosion coating for steel structures and its method of preparation, the raw material for the preparation of said coating comprising the components following weights: 30 to 60 parts of modified composite silica airgel, 80 to 100 parts of bisphenol A type epoxy resin, 5 to 15 parts of graphene oxide powder and 5 to 15 parts of curing agent; It is prepared by uniformly dispersing graphene oxide powder in an aqueous solvent, then successively adding a modified bisphenol A type epoxy resin and a modified composite silica airgel, and obtaining the first precursor by a treatment of ultrasonic agitation; The first precursor is mixed with the curing agent and then held at 70-90°C for 1-2h, then heated to 110-130°C and held for 1-2h to obtain an anti-corrosion insulating coating for the surface of the steel structure. The invention is based on the easy availability of raw materials, mild reaction conditions, low preparation difficulties and the preparation of coatings with good corrosion resistance, good thermal insulation and hydrophobic properties.

Description

Insulation of the surface of a steel structure and anti-corrosion coating and its preparation method

Technical area

The present invention relates to the technical field of the protection of steel structures, and in particular to a steel structure surface insulation and an anti-corrosion coating, as well as to its method of preparation.

Core Technology

Due to its lightness and ductility, steel is one of the main types of modern building materials used in the production of structures such as bridges. However, due to the very nature of the metal matrix, steel structures are more severely affected by corrosion, so it is important to seek an effective anti-corrosion material in order to avoid corrosion damage.

In order to provide effective protection to steel structures, the prior art has proposed a variety of anti-corrosion materials, among which water-based acrylic anti-corrosion coatings are preferred by those skilled in the art due to their excellent resistance. weather resistance, heat resistance and low cost.

However, existing technology introduces a series of hydrophilic compounds such as carboxyl groups, hydroxyl groups, emulsifiers and initiators in the preparation of water-based acrylic anti-corrosion coatings, resulting in poor water resistance and weathering of the coating film, which is not conducive to use as an anti-corrosion coating for building materials (such as steel structures of bridges) whose working environment is characterized by high water content and climate change.

To this end, the present invention provides a steel surface insulation and anti-corrosion coating suitable for use on bridges, as well as a process for preparing it.

Content of the invention

In order to solve the aforementioned deficiencies of the prior art, the present invention provides a steel structure surface insulation and anti-corrosion coating BE20295045, as well as its preparation method.

A steel structure surface insulation and anti-corrosion coating of the present invention and its preparation method are realized by the following technical solutions:

A first object of the present invention is to provide a steel structure surface insulation and an anti-corrosion coating, the raw material for the preparation of which consists of the following weight components: 30 to 60 parts of composite silica airgel modified, 80 to 100 parts of bisphenol A type epoxy resin, 5 to 15 parts of graphene oxide powder and 5 to 15 parts of curing agent;

Said modified composite silica airgel has a large number of amino acids attached to its surface.

Further, said modified composite silica airgel is produced by the following steps:

Then, the aniline and the initiator were added in turn, and under the action of the initiator, the aniline and the straw-based water glass were polymerized in the aqueous solvent, and then the pH was adjusted to 8-10, and y-aminopropyltriethoxysilane (KH-550) silane coupling agent was added and mixed, followed by static aging and drying to an area of 1.5-2.5 mm. A composite silica airgel modified with a large number of amino groups was obtained.

Further, said initiator being ammonium persulfate or potassium persulfate;

Said initiator has a molar ratio of 1 to 1.2:1 with respect to aniline.

Further, said straw-based water glass is used in an amount ratio of 1mg:4 to 6mL with said water solvent.

Further, the dosage ratio of said aniline to said straw-based water glass is 4 to 5:1.

Further, said molar ratio of said γ-aminopropyltriethoxysilane to said aniline is greater than 1.2:1.

Furthermore, said polymerization reaction is carried out at a temperature of 0 to 5°C DE 2063/5068 and at a reaction time of 2 to 4 hours.

Further, said straw water glass is prepared by the following steps: take a quantity of corn stover and dry it at a temperature of 80-120°C for 1-3h, then increase the temperature to 500-700 °C and maintain it for 1.5 to 2.5 hours to obtain heat-treated corn stover.

The heat-treated corn stover was ground into balls and evenly dispersed in a dilute alkaline solution, then kept at a temperature of 70-85°C for 1.5-2.5 hours to obtain a straw-based water glass ;

wherein said dilute alkaline solution is a NaOH solution with a mass concentration of 3 to 6% and the ratio of said dilute alkaline solution to said heat-treated corn stover is 3 to 6 mL:1 mg.

A second object of the present invention is to provide a process for the preparation of the above-mentioned steel structure surface insulation anti-corrosion coating, comprising the following steps:

Step 1, weighing the individual ingredients for preparing said primer coating according to the ratio of said structural steel surface insulation and anti-corrosion coating, respectively, and setting them aside;

Step 2, the weighed graphene oxide powder is evenly dispersed in an aqueous solvent, then the modified bisphenol A epoxy resin and the modified composite silica airgel are added in turn, and by ultrasonic stirring treatment , so that the graphene oxide powder is evenly dispersed in the gaps of the lattice structure of the bisphenol A epoxy resin and the modified composite silica airgel, while the amino group of the silica airgel modified composite and the hydroxyl group on the bisphenol A epoxy resin are to obtain the first precursor;

Step 3, mixing the first precursor with the curing agent and subsequent holding at a temperature of 70-90°C for 1-2h, then increasing the temperature to 110-130°C and holding for 1-2h to obtain said surface insulation and anti-corrosion coating of steel structure.

Further, in step 2, the dosage ratio of said graphene oxide powder to DE 2063/5068 aqueous solvent is 5-10mg:1mL.

In addition, in step 2, the ultrasonic power of said ultrasonic stirring treatment is 80-100W, the ultrasonic frequency is 40KHZ, the stirring speed is 110-150r/min, and the treatment time is from 30-90min.

The present invention has the following beneficial effects over the prior art:

After mixing with the epoxy resin, the amino group of the modified composite silica airgel can bond with the hydroxyl group of the bisphenol A epoxy resin to form a tightly connected network structure, and the graphene oxide powder can fill the network structure, which further improves the density of the network structure of the coating and makes the components of the coating denser.

The high crosslinking density of the coating prevents the formation of holes in the bisphenol A epoxy resin, which improves the hydrophobicity and thermal insulation of the coating, thus effectively avoiding the corrosion of steel caused by the adsorption of the atmospheric moisture on the steel surface and improving the corrosion resistance of the coating on the steel surface.

The good adhesion of both the modified composite silica airgel and the bisphenol A epoxy resin in the coating of the present invention allows them to act as a binder in addition to fulfilling their main role, which allows the coating of the present invention to be tightly bonded between the components without the addition of additional binders.

The presence of the epoxy bisphenol A resin in the coating of the present invention allows it to adhere tightly to the surface of the steel structure, which helps part of the coating to penetrate into the surface of the steel structure and form a dense film, which further improves the anti-corrosion performance of the coating on the surface of the steel structure.

The graphene oxide in the coating of the present invention not only improves the density of the lattice structure of the coating of the present invention, but also improves the strength of the coating and, to some extent, the wear resistance of the coating. . BE20295045

The modified composite silica airgel of the present invention forms a complex of straw-based water glass and polyaniline by polymerizing straw-based water glass and aniline, which further improves and then strengthens the strength of the skeleton 5 and the anticorrosive properties of the coating by cross-linking inorganic substances with each other and with the polymer; The silica in the polyaniline-straw water glass complex is modified with Y-aminopropyl triethoxysilane, so that a large number of amino groups are attached to the surface, and a modified composite silica airgel is obtained, thus avoiding the agglomeration of the silica in the water glass complex based on straw and polyaniline, improving the stability of the complex itself, and improving the reactivity of the coating, as well as the adhesion of the coating. The presence of a layer of silica in the modified composite silica airgel also improves the hydrophobicity of the coating, which reduces the effect of humidity from the external environment on the coating and increases the service life. of the coating.

The straw-based hydroglass of the present invention is obtained by heat treatment, so that the straw-based hydroglass has a certain amount of carbon fibers, which enables the modified composite silica airgel to be distributed in the lattice structure of the coating together with graphene oxide during the mixing process with bisphenol A epoxy resin, which together improves the density of the lattice structure of the coating and achieves improved hydrophobicity of the coating of the present invention.

The invention is based on the easy availability of raw materials, mild reaction conditions, low preparation difficulties and the preparation of coatings with good corrosion resistance, good thermal insulation and hydrophobic properties.

Specific implementation methods

The technical solutions in embodiments of the invention will be clearly and completely described below in connection with the drawings accompanying the embodiments of the invention.

Example 1 BE2023/5045

This example provides an insulating and anti-corrosion coating for steel surface prepared from the following components by weight: 45 parts of modified composite silica airgel, 90 parts of bisphenol A epoxy resin, 10 parts of graphene oxide powder and 10 parts ammonium persulfate curing agent.

And the method of preparing the anti-corrosion coating of the surface insulation of the steel structure of this embodiment is as follows:

Step 1, weigh each raw material for preparing said primer coating according to the insulation ratio of steel structure surface and anti-corrosion coating mentioned above, respectively, and set aside;

In step 2, the weighed graphene oxide powder is evenly dispersed in deionized water according to the dosage ratio of 7mg:1mL graphene oxide powder to water solvent, then the modified bisphenol A epoxy resin and the modified composite silica airgel are added in turn, and treated with an ultrasonic power of 90 W and a stirring speed of 130 r/min for 60 min, so that the powder of graphene oxide is evenly dispersed in the spaces of the network structure of the bisphenol A epoxy resin and the modified composite silica airgel. and gaps in the lattice structure of the modified composite silica airgel, while part of the amino group on the modified composite silica airgel could bond to the hydroxyl group on the bisphenol A type epoxy resin under the energy provided by ultrasound to obtain the first precursor.

In step 3, the first precursor is mixed with the curing agent and then held at a temperature of 85°C for 1.5h and then heated to 120°C at a rate of 5°C/min and then held for 1.5 hours to obtain said steel structure surface insulation and anti-corrosion coating.

Example 2

This example provides a steel surface insulating and anti-corrosion coating prepared from the following components by weight: 30 parts modified composite silica airgel, 80 parts bisphenol A epoxy resin, 5 parts powder — graphene oxide and 5 parts ammonium persulfate curing agent.

And the method of preparing the anti-corrosion coating of the surface insulation of DE 2063/5068 the steel structure of this embodiment is as follows:

Step 1, weigh each raw material for preparing said primer coating according to the insulation ratio of steel structure surface and anti-corrosion coating mentioned above, respectively, and set aside;

In step 2, the weighed graphene oxide powder is evenly dispersed in deionized water according to the dosage ratio of 5mg:1mL graphene oxide powder to water solvent, followed by the adding the modified bisphenol A epoxy resin and the modified composite silica airgel in turn, and treated under the condition of 80W ultrasonic power and 110r/min stirring speed for 90min, so that the powder of graphene oxide is uniformly dispersed in the space of the network structure of the bisphenol A epoxy resin and the modified composite silica airgel. and gaps in the lattice structure of the modified composite silica airgel, while part of the amino group on the modified composite silica airgel could bond to the hydroxyl group on the bisphenol A type epoxy resin under the energy provided by ultrasound to obtain the first precursor.

In step 3, the first precursor is mixed with the curing agent and then held at a temperature of 70°C for 2h and then heated to 120°C at a rate of 5°C/min and then held for 2h to obtain said steel structure surface insulation and anti-corrosion coating.

Example 3

This embodiment provides a coating for surface insulation and corrosion protection of steel prepared from the following components by weight: 60 parts modified composite silica airgel, 100 parts bisphenol epoxy resin

A, 15 parts graphene oxide powder and 15 parts ammonium persulfate curing agent.

And the method of preparing the anti-corrosion coating of the surface insulation of the steel structure of this embodiment is as follows:

Step 1, weigh each raw material for preparing said primer coating according to the insulation ratio of steel structure surface and BE20295045 anti-corrosion coating mentioned above, respectively, and set aside;

In step 2, the weighed graphene oxide powder was evenly dispersed in deionized water according to the dosage ratio of 10mg:1mL graphene oxide powder to water solvent, then the resin modified bisphenol A epoxy and the modified composite silica airgel were added in turn, and treated under the condition of ultrasonic power of 100W and stirring speed of 150r/min for 30min, so that the oxide powder of graphene was evenly dispersed in the gaps of the lattice structure of the bisphenol A epoxy resin and the modified composite silica airgel. AT and the modified composite silica airgel in the interstices of the network structure, at the same time, part of the amino group on the modified composite silica airgel was able to bond to the hydroxyl group on the bisphenol A epoxy resin under the energy provided by ultrasound to obtain the first precursor;

In step 3, the first precursor is mixed with the curing agent and then held at a temperature of 90°C for 1h and then heated to 120°C at a rate of 5°C/min and then held for 1h to obtain said steel structure surface insulation and anti-corrosion coating.

Example 4

This embodiment provides a surface insulation and corrosion protection coating for a steel structure, this embodiment differs from embodiment 1 only in that:

The curing agent in this embodiment is potassium persulfate.

Contrast example 1

This proportion provides an insulating coating of the steel surface and protection against corrosion, this proportion differs from Example 1 only in that:

It does not contain graphene oxide.

Contrast example 2

This proportion provides a coating of insulation of the surface of the steel structure and protection against corrosion, this proportion differs from example 1

, BE2023/5045 only in that:

The modified composite silica airgel of this proportion is prepared from ordinary water glass (made of sodium silicate) commonly used in this field.

Contrast example 3

This proportion provides an insulating coating of the steel surface and protection against corrosion, this proportion differs from Example 1 only in that:

In the preparation of the modified composite silica airgel, γ-aminopropyltriethoxysilane is not used for the modification process.

It should be noted that the graphene oxide powder used in each of the above embodiments of the invention is prepared by the conventional method

Hummers, which should be known to those skilled in the art and is therefore not repeated herein.

In each of the above embodiments of the present invention, the modified composite silica airgel is produced by the following steps:

Preparation of a straw-based water glass:

Take some amount of corn straw and crush it to 80 mesh, then dry it in a tube oven at 80-120°C for 1-3h to remove most of the water in the corn straw, then heat it at 500-700°C at a heating rate of 10-20°C/min for 1.5-2.5h to obtain the heat-treated corn straw; After balling the heat-treated corn straw to 200 mesh, the balling corn straw is evenly dispersed in the dilute alkaline solution, i.e. NaOH solution with a mass concentration of 3 -6%, depending on the dosage ratio of 3-6mL:1mg of alkaline solution diluted to said heat-treated corn straw, sonicated for 5-20min to make it evenly dispersed, and then held at a temperature of 70-85°C for 1.5-2.5 hours. We then obtain the straw-based water glass.

Modified Composite Silica Airgel:

According to the dosage ratio of straw-based water glass and water solvent

1mg:4-6mL, weigh the corresponding mass of the water glass made from straw and DE 2063/5068 deionized water respectively, then take half the amount of deionized water and add the glass to the straw-based water weighed, put it under the ultrasonic power of 80W for 10min, make the straw-based water glass evenly dispersed in the deionized, adjust the pH of the system with the concentration hydrochloric acid solution mass 1mol/L at 1.5-2.5 to obtain solution A.

Add the weighed aniline to the other half of the deionized water and stir at 120r/min for 10min to obtain solution B; Solution A was then placed in an ice bath and solution B was added dropwise to solution A, stirred at 60

rpm while adding dropwise, then kept in an ice bath, stirred at 60 rpm while adding initiator dropwise, and after 2h of reaction, the pH was adjusted to 8-10 with a solution of NaOH at a mass concentration of 10%; According to the molar ratio of Y-aminopropyltriethoxysilane to aniline 1-1.2:1, Y-aminopropyltriethoxysilane was added and mixed, then left for 24h, soaked in ethanol and deionized water for 36h respectively, replaced every 12 hours, then dried to a water content of 10% or less to obtain a modified composite silica airgel with a large amount of surface-attached amino groups.

testing section

Six plates of Q235 (70mm x 50mm x 2mm) were taken as the test plates, the surface of the test plates were sanded and cleaned with ethanol! and acetone, then the surface solvent was removed in a vacuum oven at 60°C to obtain the specimens.

Using the electrostatic spray method, the coatings of Examples 1-3 and Proportions 1-3 of the present invention were sprayed onto the surface of 6 treated specimens and formed a powder layer 100 microns thick, followed by heating in an oven at 190°C for 20 minutes to completely harden the powder and obtain coated specimen sheets. (i) Thermal insulation performance test (1) Thermal conductivity test

. | | , _ BE2023/5045

The lower the thermal conductivity, the better the thermal insulation performance.

The invention was tested in accordance with the test method of the ISO22007-2 standard for the thermal conductivity of examples 1-3 of the invention and for the coatings of the proportions 1-3, the results of which are indicated in the table 1. 2) Test of resistance to temperature changes

The invention takes the resistance to temperature change as another indicator of the insulation performance of the coating of the invention, and the resistance to temperature change of the coating of Examples 1-3 of the invention together with the pair of proportions 1-3 is tested according to the test method of JG/T 25-2017, and the test results are shown in Table 1.

Table 1 Thermal insulation test results

Example 1 Example 2 Example 3 | Contrast Contrast Contrast

Example 1 | Example2 | Example 3

Thermal conductivity 0.20 0.27 0.31 0.45 0.34 0.36 W/(m

Resistance to | Coating Coating Coating | Coating Coating Powder-free denaturation coating, | without powdering, | without no without degreased, thermal without without powdering, powdery, dusting, no cracking, cracking, without no | slightly cracking, without flaking, | without chipping, | cracking, cracking, cracked, without | not without bubbles, | without bubbles, | without flaking, flaking, without without flaking, flaking, without bubbles, | with little discoloration discoloration without bubbles, | with little | no bubbles, no no bubbles, no | discoloration discoloration | discoloration discoloration.

As can be seen in Table 1, the thermal insulation performance of the coatings of Examples 1 to 3 of the present invention are better than those of - proportions 1 to 3, indicating that graphene oxide and modified composite silica airgel have a greater impact on the thermal insulation performance of coatings.

The fact that the ratio of the components of Example 2 is lower than the ratio of the components of Example 1 and lower than the ratio of the components of Example 3, while the thermal insulation properties of Example 1 > the thermal insulation properties of example 2 > the thermal insulation properties of example 3, shows that the performance of the coating in this application is not a superposition of the functions of a single component, but is obtained by the synergy between the components together. (II) Anti-Corrosion Performance Test

The invention uses the resistance to neutral salt spray as an index of anticorrosion performance of the coating of the invention. The resistance to neutral salt spray of the coatings of Examples 1 to 3 of the invention was determined according to the method for determining the standard GB/T 1771-2007 "Determination of neutral salt spray resistance of color paints and varnishes", and the Test results are shown in Table 2.

Table 2 Neutral salt spray resistance test results

Example 1 | Example 2 | Example 3 | Contrast | Contrast | Contrast

Example l | Example 2 | Example 3

Resistance to | After 1005h | After 990h | No rust | After 910h | After 850h | After 880h salt spray | of fog | of resistance | no bubbles | of resistance | of resistance | saline neutral resistor, | to fog | of air in the | to fog | to fog | to fog the coating | neutral saline, | neutral saline coating, | neutral saline, | neutral saline, is free | the coating | after 900h | no | the coating | the rust coating and | is exempt | of resistance | rust, of | appears appears bubbles. of rust and | to fog | rusty bubbles and | rusty and bubbles. salt neutral. | begin | exempt from |exempt from to appear. | air bubbles. air bubbles.

As can be seen in Table 2, the neutral salt spray resistance of Examples 1 to 3 of the present invention is better than that of Proportions 1 to 3, indicating that graphene oxide and silica airgel modified composite both have a greater impact on the neutral salt spray resistance of the coating.

The fact that the ratio of the components of Example 2 is lower than the ratio of DE 2063/5068 components of Example 1 and lower than the ratio of the components of Example 3, while the neutral salt spray resistance of the example 1 > resistance to neutral salt spray from example 2 > resistance to neutral salt spray from example 3, shows that the performance of the coating in this application is not the superposition of the functions of a single component, but is obtained by the synergistic effect between the components.

It is clear that the embodiments described above are only part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained without creative work by a person of ordinary skill in the art fall within the scope of protection of the present invention.

Claims (10)

Claims 1. An anti-corrosion coating for insulating the surface of a steel structure, characterized in that the raw material for its preparation consists of the following components by weight: 30-60 parts of modified composite silica airgel, 80 to 100 parts of bisphenol A type epoxy resin, 5 to 15 parts of graphene oxide powder and 5 to 15 parts of curing agent; Said modified composite silica airgel has a large number of amino groups attached to its surface. 2. Steel structure surface insulation and anti-corrosion coating according to claim 1, characterized in that said modified composite silica airgel is produced by the following steps: Uniformly dispersing the straw-based waterglass in an aqueous solvent , adjust pH to 1.5-2.5, then add aniline and initiator in turn for polymerization reaction, then adjust pH to 8-10, add silane coupling agent and mix well , then dried after static aging to obtain a modified composite silica airgel with a large number of amino groups attached to the surface. 3. A surface insulation and corrosion protection coating for steel according to claim 2, characterized in that said straw-based water glass has a dosage ratio of 1mg:4 to 6mL of aqueous solvent ; said molar ratio of said initiator to said aniline being from 1 to 1.2:1; said dosage ratio of said aniline to said straw based water glass is 4 to 5:1. 4. Surface insulation and corrosion protection coating for steel structure according to claim 2, characterized in that the molar ratio of said γ-aminopropyltriethoxysilane to said aniline is 1 to 1.2:1. 5. Insulating and anti-corrosion coating for steel surface according to claim 2, characterized in that said polymerization reaction is carried out at a temperature of 0 to 5°C and a reaction time of 2 to 4 hours. 6. Steel structure surface insulation and anti-corrosion coating according to DE 2063/5068 claim 2, characterized in that said straw-based water glass is produced by the following steps: A certain amount of corn straw is taken and it is dried at a temperature of 80-120°C for 1-3h, then the temperature is increased to 500-700°C and maintained for 1.5-2.5h to obtain heat-treated corn straw; the heat-treated corn straw is ground into a ball and evenly dispersed in a dilute alkaline solution, then kept at a temperature of 70-85°C for 1.5-2.5h, i.e. you get a straw-based water glass. 7. Surface insulation and corrosion protection coating for steel structure according to claim 6, characterized in that said dilute alkaline solution is used in a ratio of 3 to 6 ml: 1 mg of said corn stover heat treated. 8. Process for the preparation of a metal structure surface insulation anticorrosion coating according to any one of claims 1 to 7, characterized in that it comprises the following steps: Step 1, weighing each raw material for the preparation of said primer coating in accordance with the insulation ratio of the steel structure surface and anti-corrosion coating mentioned above, respectively, and set aside; Step 2, the weighed graphene oxide powder is evenly dispersed in an aqueous solvent, then the modified bisphenol A epoxy resin and the modified composite silica airgel are added in turn, and through ultrasonic stirring treatment , so that the graphene oxide powder is evenly dispersed in the gaps of the lattice structure of the bisphenol A epoxy resin and the modified composite silica airgel, while the amino group of the silica airgel modified composite and the hydroxyl group on the bisphenol A epoxy resin are to obtain the first precursor; Step 3, mixing the first precursor with the curing agent and subsequent holding at a temperature of 70-90°C for 1-2h, then increasing the temperature to 110-130°C and holding for 1-2h to obtain said DE 2063/5068 surface insulation and anti-corrosion coating of the steel structure. 9. Preparation process according to claim 8, characterized in that in step 2, the dosage ratio of said graphene oxide powder to said aqueous solvent is 5 to 10 mg:1 mL. 10. Preparation method according to claim 8, characterized in that in step 2, the ultrasonic power of said ultrasonic agitation treatment is 80-100W, the ultrasonic frequency is 40KHZ, the agitation speed is 110 -150r/min and processing time is 30-90min.