WO2021027370A1

WO2021027370A1 - Rigid and high-temperature-resistant polyurea anti-corrosion coating and preparation method therefor

Info

Publication number: WO2021027370A1
Application number: PCT/CN2020/093649
Authority: WO
Inventors: 王道前; 肖国亮; 连联益
Original assignee: 王道前; 肖国亮; 连联益
Priority date: 2019-08-12
Filing date: 2020-05-31
Publication date: 2021-02-18
Also published as: CN110499092A; CN110499092B

Abstract

Disclosed is a rigid and high-temperature-resistant polyurea anti-corrosion coating. The polyurea anti-corrosion coating comprises a component A and a component B, wherein the component A comprises the following raw materials for preparation in parts by mass: 80-90 parts of a polyisocyanate and 10-20 parts of a polyester polyol; and the component B comprises the following raw materials for preparation in parts by mass: 10-30 parts of an amine-terminated polyether, 10-30 parts of an amino chain extender, and 40-70 parts of a ultra-tough polyether amine. The rigid and high-temperature-resistant polyurea anti-corrosion coating does comprise any added catalyst, has low requirements for the humidity of the construction environment and a good toughness, and can be used for a long time at temperatures of less than 160°C.

Description

Rigid high temperature resistant polyurea anticorrosive coating and preparation method thereof

Technical field

The invention belongs to the technical field of polyurea coatings, and specifically relates to a rigid, high-temperature resistant polyurea anticorrosive coating and a preparation method thereof.

Background technique

Polyurea anticorrosive coating is a pure polyurea anticorrosive coating system. It has excellent corrosion resistance and anti-aging properties, especially in terms of atmospheric corrosion resistance and low acid and alkaline media and inorganic salt solutions. , High adhesion, the coating is not easy to crack, and the anti-permeability ability is strong. It is a new type of material in the field of anti-corrosion, with the characteristics of long-term effect and wide applicability.

Polyurea is usually formed by two-component reaction, but because the reaction speed is extremely fast, it will cure within a few seconds, which cannot be achieved by manual operation. Therefore, polyurea is generally formed by special mechanical spraying. The main characteristics of spray polyurea coatings are as follows: (1) Fast curing and high construction efficiency. The curing speed after polyurea spraying is extremely fast. Generally, the gel will not stick to hands within a few seconds, and it will reach walking strength after a few hours. The construction site can enter the next process. The thickness of polyurea spray molding can be set arbitrarily, from less than 1mm to several millimeters can be completed at one time. Spraying construction on the vertical surface or even the top surface can also ensure smoothness and no flow phenomenon, which gives the spraying polyurea process great construction efficiency. (2) It can be applied with wet construction. Since polyurea reacts very fast at room temperature, water molecules in this system cannot react with isocyanate. Therefore, the humidity around the environment will not adversely affect the quality and surface of the coating. Greatly facilitate the construction. (3) High strength, the modulus of sprayed polyurea is similar to rubber, that is, it has a higher elongation at break while still maintaining a higher strength. Through formula adjustment, the tensile strength of sprayed polyurea can be Change within 10-22MPa, this range basically covers the properties of plastic, rubber and glass fiber reinforced plastic, which is very beneficial for being used as a waterproof material. (4) Excellent aging resistance. Due to the specific molecular structure of polyurea and the absence of catalyst in the formula, the aging resistance of sprayed polyurea is particularly excellent. Although the aromatic system material will appear yellowing soon after use, it does not Will affect the performance, but the aliphatic system polyurea coatings have better aging resistance. (5) Good salt corrosion resistance, spray polyurea coating as an anticorrosive coating, can withstand dilute acid and dilute alkali corrosion, and has outstanding resistance to salt water or salt spray corrosion, which makes it particularly suitable for coastal areas .

Ordinary polyurea anticorrosive paint coatings are required to be used at 80°C and below. Excessive temperature will make the mechanical properties and anticorrosion properties drop sharply, and the coating will become soft and blistering. In order to expand the applicable temperature range of the polyurea anticorrosive coating, the present invention provides a rigid high temperature resistant polyurea anticorrosive coating. The advantages of rigid, high temperature resistant polyurea anticorrosive coatings are mechanical properties, anticorrosion properties, bonding strength, good impact resistance, a certain degree of toughness, good abrasion resistance, and little impact on the environment. The shortcomings are that at present Domestic independent production capacity is insufficient, and product prices are relatively high.

In the 1970s, the 100% solid rigid polyurea anticorrosive coating technology was successfully developed in North America. It has become one of the most widely used anticorrosive coating technologies in North America and represents the development direction of the coating industry in the 21st century. With more than 30 years of successful application history, it has advanced spraying technology, stable quality, fast coating curing, convenient and quick construction, and high efficiency. It can be widely used for corrosion prevention of steel, cast iron, cement and other substrates.

At present, in China, spraying rigid polyurea anticorrosive coating consists of two components, one is isocyanate semi-prepolymer, and the other is polyether polyol, alcohol chain extender, water absorbing agent, catalyst, etc. Due to the low activity of polyether, it is necessary to add a catalyst to accelerate the reaction, but the addition of the catalyst is very sensitive to moisture. During the construction process, the system easily reacts with the moisture and humidity in the surrounding environment to produce carbon dioxide and generate foam-like elastomers, causing mechanical The performance drops sharply, and the coating is prone to foaming and bulging. Therefore, the moisture and humidity requirements of the construction environment are very high, which limits its development.

For example, patent document CN201711129146.6 discloses a method for preparing a polyurea waterproof coating applied to the surface of concrete. When using TDI (toluene-2,4-diisocyanate), polyether, DMPA and other materials to prepare modified polyurethane, An organotin catalyst is added, and the organotin catalyst refers to dibutyltin dilaurate. Dibutyl tin dilaurate as a catalyst is extremely sensitive to water in the construction environment, and requires a dry environment for construction. The polyurea coating is not suitable for southern areas with high humidity, which greatly reduces the cost of polyurea coatings. Range of use.

For another example, the patent document CN200810031397.5 is the closest prior art to the present invention, which discloses a spraying high temperature and acid resistant polyurea anticorrosive coating for desulfurization flue lining, which is composed of A component and B component according to the volume ratio It is a mixture of 1:0.5-2.0. The A component is a mixture of a semi-prepolymer synthesized from 100 parts by weight of polyisocyanate with a functionality of 2.0-2.9 parts by weight and 35-50 parts by weight of polyester polyol and 2-10 parts by weight of reactive diluent; The B component is composed of 150-250 parts by weight of polyether polyamine, 1000-1200 parts by weight of polyester polyamine, 500-620 parts by weight of chain extender, 80-90 parts by weight of crosslinking agent, 130 -160 parts by weight of diluent, 3-15 parts by weight of catalyst, 500-600 parts by weight of filler, and 50-60 parts by weight of color paste are mixed and dehydrated. Similarly, the polyurea coating uses tertiary amine compounds or organotin as a catalyst. If it is constructed in an environment with high humidity, the coating is prone to foaming, bulging, falling off and the like.

Patent document CN201811054697.5 discloses a polyurea elastic anticorrosive coating and a preparation method thereof, which include component A and component B in parts by weight. The component A includes: polyether polyol N220, polyether polyol N330, isocyanate MDI-50; the component B includes: amino-terminated polyether D-2000, amino-terminated polyether T-5000, amino chain extender E-100, and amino chain extender 6200. The raw materials for the preparation of the polyurea anticorrosive coating are all conventional materials. Although various physical and mechanical properties of the coating are required by the specifications, the application temperature is a conventional temperature and has no high temperature resistance effect, and is not suitable for high temperature environments above 100°C.

Summary of the invention

One object of the present invention is to provide a rigid high temperature resistant polyurea anticorrosive coating and a preparation method thereof, and another object of the present invention is to provide a use of a rigid high temperature resistant polyurea anticorrosive coating.

In order to overcome the shortcomings of the prior art, the present invention provides a rigid, high-temperature resistant polyurea anticorrosive coating. When the rigid polyurea anticorrosive coating is constructed, because no catalyst is added during the preparation, it is not sensitive to moisture, and the humidity of the construction environment is not required. High, while maintaining the characteristics of "rigid and soft", will not be brittle due to high crosslinking density, and can be used for a long time at a temperature of 160 ℃, further increasing the temperature range of spraying polyurea.

The purpose of the present invention is achieved through the following technical solutions:

The present invention provides a rigid, high-temperature resistant polyurea anticorrosive coating. The polyurea anticorrosive coating includes component A and component B, wherein component A includes the following raw materials by mass: 80-90 parts of polyisocyanate, poly 10-20 parts of ester polyol; B component includes the following raw materials by mass: 10-30 parts of amino-terminated polyether, 10-30 parts of amino chain extender, and 40-70 parts of super-tough polyetheramine.

Wherein, the polyisocyanate is selected from: polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, toluene diisocyanate, One or a combination of two or more of diphenylmethane diisocyanate (MDI).

Preferably, the polyisocyanate is selected from: polymethylene polyphenyl polyisocyanate (PAPI), and the PAPI contains 60-70% MDI and other isomers and similar higher polyisocyanates.

Wherein, the polyester polyol has a molecular weight of 2000-3500, a hydroxyl value of 360-400 mg KOH/g, an acid value ≤ 2.0 mg KOH/g, a moisture content ≤ 0.1%, and a viscosity ≤ 4000 mPa·s.

Wherein, the amino-terminated polyether is a polyetheramine with a molecular weight of 2000-5000. In a preferred embodiment of the present invention, the amino-terminated polyether is Jaffamine D-2000 or Jaffamine T-5000.

Wherein, the amino chain extender is selected from one or a combination of two or more of diethyltoluenediamine (DETDA), Ethancure-100 (E-100), and dimethylthiotoluenediamine (DMTDA). In a preferred embodiment of the present invention, the amino chain extender is DETDA.

Wherein, the ultra-tough polyetheramine is selected from polyetheramines with 3 secondary amine end caps.

In a preferred embodiment of the present invention, the general structural formula of the super-tough polyetheramine is as follows:

and / or

among them,

n is an integer between 6-12,

m is an integer between 9-18.

In the present invention, the preparation process of the super tough polyetheramine of general formula I is as follows:

among them,

n is an integer between 6-12,

Specifically, compound 1 is added to the reactor, nitrogen is introduced, compound 2 is slowly added dropwise with stirring, the catalyst is added, and the reaction is stirred for 12-24 hours to obtain the super-tough polyetheramine with general formula I.

Wherein, the catalyst is selected from one or a combination of two or more of zinc chloride, sodium ethoxide, sodium hydride, sodium amide or organic base.

In the present invention, the preparation process of the super tough polyetheramine of general formula II is as follows:

among them,

m is an integer between 9-18.

Specifically, 1-3 times the molar amount of epichlorohydrin was added to compound 3, reacted for 6-12 hours, and the alkali solution was added dropwise. After completion, the reaction was kept for 3-5 hours, and then distilled under reduced pressure, and 2 was added to the concentrated product. -Propylamine at a temperature of 60-100°C and react for 5-10 hours to obtain a super-tough polyetheramine of general formula II.

In a preferred embodiment of the present invention, the A component also includes 3-7 parts of trimethylolpropane trimethacrylate (TMPTMA). TMPTMA is usually used to modify epoxy acrylate, polyurethane, and unsaturated Polyester coatings, used to shorten curing time and improve bonding strength. However, in the present invention, the inventor found that adding TMPTMA to component A can increase the adhesion and wear resistance of the polyurea anticorrosive coating to the substrate, and increase the toughness of the coating.

Preferably, the B component also includes one or a combination of two or more of leveling agent, 0.1-1 part of anti-ultraviolet agent, 0.01-1 part of antioxidant, and 0.1-2 part of pigment and filler. .

Wherein, the leveling agent is selected from one or two of polyacrylate leveling agents and polyester modified polysiloxane leveling agents.

Wherein, the anti-ultraviolet agent is selected from triazine anti-ultraviolet agent, oxybenzophenone anti-ultraviolet agent, benzotriazole anti-ultraviolet agent, salicylate anti-ultraviolet agent, benzophenone anti-ultraviolet agent, cyanogen Base acrylate anti-ultraviolet agent or nickel complex salt anti-ultraviolet agent.

Wherein, the antioxidant is selected from 2,6-di-tert-butyl-p-cresol, pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] or triethylene glycol Alcohol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate].

Wherein, the pigments and fillers are selected from one or a mixture of several in any ratio among iron oxide red, titanium dioxide, barium sulfate, talc, and mica powder.

On the other hand, the present invention provides a method for preparing the rigid, high temperature resistant polyurea anticorrosive coating, which includes the following steps:

(1) Dehydration of polyester polyol: Dehydrate the polyester polyol at 110-120°C and a vacuum of -0.08 to -0.1Mpa for 2-3 hours, and then lower to room temperature for later use;

(2) Preparation of component A: Put the polymethylene polyphenyl polyisocyanate into the reactor, and when the temperature is raised to 45-50°C, slowly add the dehydrated polyester polyol prepared in step (1), 1-1.5 After the hour drop is completed, the temperature is raised to 80-90°C, the temperature is kept for 2-3 hours, and the NCO content is measured by sampling. When the NCO content is 23.0-24.5%, it is cooled to room temperature, filtered, and sealed with nitrogen.

(3) Preparation of component B: Put the amino-terminated polyether into a mixing tank, add super-tough polyetheramine and amino chain extender, stir at 400-500 rpm for 45-60 minutes, filter, and pack for use;

(4) Mix component A and component B in a ratio of 1:2-3 to obtain a rigid, high temperature resistant polyurea anticorrosive coating.

Preferably, the step (2) further includes adding trimethylolpropane trimethacrylate after the dripping of the dehydrated polyester polyol is completed, and stirring uniformly.

Preferably, the step (3) further includes adding one or a combination of two or more of a leveling agent, an anti-ultraviolet agent, an antioxidant, and pigments and fillers before the filtration, and stirring uniformly.

Preferably, the application method of the rigid, high-temperature resistant polyurea anticorrosive coating is spraying. The A component and the B component are combined and mixed under high pressure. Preferably, the A component and the B component are directly impacted in the high-pressure spraying equipment. mixing. Specifically, the A component and the B component are heated in two separate chambers, pressurized separately, and impact or collide with each other at high speeds to achieve tight mixing between the two components, and then apply to the On the substrate.

In the present invention, the rigid, high temperature resistant polyurea anticorrosive coating can be used at a temperature of 160°C and below.

The invention also provides the application of the rigid, high-temperature resistant polyurea anticorrosive coating in the anticorrosion of metal or concrete surfaces that generate high temperatures in the electric power, petroleum, chemical, pharmaceutical, automobile manufacturing, and railway fields. Preferably, the metal or concrete surface The temperature is ≤160℃.

The beneficial effects of the present invention are as follows: (1) The rigid polyurea anticorrosive coating is not sensitive to moisture because it does not add any catalyst, so the humidity requirement of the construction environment is not high; (2) the rigid polyurea anticorrosive coating is added Trimethylolpropane trimethacrylate and/or super-tough polyetheramine provide the coating with sufficient toughness and crosslinking density, so that the coating has the characteristics of "rigid and flexible", and will not be caused by excessive crosslinking density. High and brittle; (3) The polyurea anticorrosive coating prepared by the invention can be used for a long time at a temperature of 160 DEG C. Compared with the prior art, it has a significant improvement in the use temperature of sprayed polyurea.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Example 1

Preparation of super tough polyetheramine with general formula Ⅰ

Add 1.5 mol of three-arm polyetheramine raw material (compound 1 described in the present invention, with a molecular weight of 1600-2100) into a four-necked flask with a stirrer and thermometer, turn on the stirrer, introduce nitrogen, and slowly add Polyetheramine 3 times the molar amount of diethyl maleate, adding catalyst sodium hydride and zinc chloride (equal molar ratio) to 0.05wt%, stirring and reacting overnight to obtain super tough polyetheramine.

Example 2

Preparation of super tough polyetheramine with general formula Ⅱ

S1: Add epichlorohydrin to 1.2 mol of three-arm polyether polyol raw material (compound 3 described in the present invention, with a molecular weight of 1800-2400), and the molar amount of epichlorohydrin is the number of moles of hydroxyl groups in the polyether polyol 3 times as much as 10 hours, slowly add KOH alkali solution, the amount of alkali is 1.3 times the moles of epichlorohydrin, after 2 hours, the addition is complete, and the reaction is kept at 75°C for 5 hours;

S2: Wash the product in step S1 with water to remove the salt and residual alkaline substances therein, and then distill and dehydrate under reduced pressure to obtain a polyether polyol glycidyl ether intermediate;

S3: Add 3-fold molar amount of 2-propylamine to the polyether polyol glycidyl ether intermediate obtained in step S2, and slowly stir and react at 100° C. for 10 hours to obtain a super tough polyether amine with general formula II.

Example 3

Preparation of rigid high temperature resistant polyurea anticorrosive coating

S1: Dehydration of polyester polyol: Dehydrate 12 parts of polyester polyol at 120°C and a vacuum of -0.08Mpa for 2 hours, and lower to room temperature for use;

S2: Preparation of component A: Put 88 parts of polymethylene polyphenyl polyisocyanate into the reaction kettle, when the temperature is raised to 45°C, slowly add the dehydrated polyester polyol prepared in step (1), and add dropwise for 1 hour When finished, the temperature is raised to 80°C, the temperature is kept for 2 hours, and the NCO content is sampled. When the NCO content is 23.0%, it is lowered to room temperature, filtered, and sealed with nitrogen for storage;

S3: Preparation of component B: Put 15 parts of amino-terminated polyether Jaffamine T-5000 into the mixing tank, add 60 parts of super tough polyether amine I and 25 parts of amino chain extender diethyl toluene diamine, at 500 rpm Stir for 45 minutes, filter and pack for later use;

S4: Mix component A and component B in a weight ratio of 1:2.5 to obtain a rigid, high-temperature resistant polyurea anticorrosive coating.

Example 4

Preparation of rigid high temperature resistant polyurea anticorrosive coating

S1: The steps are the same as in Example 3;

S2: The steps are the same as in embodiment 3;

S3: Preparation of component B: put 15 parts of amino-terminated polyether Jaffamine T-5000 into the mixing tank, add 60 parts of super tough polyether amine II and 25 parts of amino chain extender diethyl toluene diamine at 500 rpm Stir for 45 minutes, filter and pack for later use;

S4: Same as Example 3.

Example 5

Preparation of rigid high temperature resistant polyurea anticorrosive coating

S1: Same as Example 3;

S2: Same as Example 3;

S3: Preparation of component B: put 15 parts of amino-terminated polyether Jaffamine T-5000 into the mixing tank, add 30 parts of super tough polyether amine Ⅰ, 30 parts of super tough polyether amine Ⅱ and amino chain extender diethyl toluene diethyl 25 parts of amine, stir at 500 rpm for 45 minutes, filter and pack for later use;

S4: Same as Example 3.

Example 6

Preparation of rigid high temperature resistant polyurea anticorrosive coating

S1: Same as Example 5;

S2: Preparation of component A: Put 88 parts of polymethylene polyphenyl polyisocyanate into the reaction kettle, when the temperature is raised to 45°C, slowly add the dehydrated polyester polyol prepared in step (1), and add dropwise for 1 hour When finished, add 5 parts of trimethylolpropane trimethacrylate, heat to 80°C, keep for 2 hours, take a sample to measure the NCO content, when the NCO content is 23.0%, drop to room temperature, filter, and store in a sealed nitrogen atmosphere;

S3: same as in embodiment 5;

S4: Same as Example 5.

Example 7

Preparation of rigid high temperature resistant polyurea anticorrosive coating

S1: Same as Example 6;

S2: Same as Example 6;

S3: Preparation of component B: put 15 parts of amino-terminated polyether Jaffamine T-5000 into the mixing tank, add 30 parts of super tough polyether amine Ⅰ, 30 parts of super tough polyether amine Ⅱ and amino chain extender diethyl toluene diethyl 25 parts of amine, stir at 500 rpm for 45 minutes, add 1 part of polyester modified polysiloxane leveling agent, 0.4 part of triazine anti-ultraviolet agent, antioxidant 2,6-di-tert-butyl-p-cresol 0.1 part, 1 part talcum powder, stir evenly, filter, and pack for later use;

S4: Same as Example 6.

Comparative Example 1

Preparation of polyurea anticorrosive coating without super-tough polyetheramine

S1: Same as Example 3;

S2: Same as Example 3;

S3: Preparation of component B: put 15 parts of amino-terminated polyether Jaffamine T-5000 into the mixing tank, 25 parts of amino chain extender diethyl toluene diamine, stir at 500 rpm for 45 minutes, add polyester modified 1 part of polysiloxane leveling agent, 0.4 part of triazine anti-ultraviolet agent, 0.1 part of antioxidant 2,6-di-tert-butyl-p-cresol, 1 part of talcum powder, stir well, filter, and pack for later use;

S4: Mix component A and component B in a ratio of 1:2.5 to obtain a rigid high temperature resistant polyurea anticorrosive coating.

Effect Example 1

Comparison of conventional properties of rigid, high-temperature resistant polyurea anticorrosive coatings

The rigid high-temperature resistant polyurea anticorrosive coating prepared in Example 3 was used as the test group, and the common solvent-containing epoxy anticorrosive coating and solvent-free epoxy anticorrosive coating were used as the control group for coating performance testing. Under the conditions of a temperature of 25°C and a relative air humidity of 55%, three 120×50×0.28mm tinplate plates were taken as the base material. The test group mixed the A component and the B component according to 1:2.5, and press 0.25kg /㎡, use Graco polyurea spraying equipment HPX-3 spraying, the control group is sprayed according to the instructions, and the performance is tested after 7 days of curing. The test results are shown in the following table.

Table 1 Performance comparison of rigid high temperature resistant polyurea anticorrosive coating and ordinary epoxy anticorrosive coating

According to the comparison results in the above table, it can be found that the rigid, high temperature resistant polyurea anticorrosive coating prepared in Example 3 of the present invention has stronger adhesion to the substrate, better wear resistance and cathodic disbondment resistance than ordinary epoxy anticorrosive coatings. , The impact strength and bending performance are stronger, but the difference between salt spray resistance, chemical resistance and aging resistance is not significant. After placing the above three kinds of anticorrosive coatings at 160°C for 7 days, the polyurea anticorrosive coating prepared by the present invention showed no brittleness, cracking, bulging or shedding, while the epoxy anticorrosive coating of the control group showed cracking, Drumming and falling off. It shows that the polyurea anticorrosive paint coating prepared by the invention has stronger high temperature resistance.

Effect Example 2

Effect of Super Tough Polyetheramine on the Properties of Polyurea Anticorrosive Coatings

In the present invention, super-tough polyetheramine is added to the B component to provide sufficient crosslinking density and toughness for the polyurea anticorrosive coating, so that the anticorrosive coating has good impact strength and wear resistance at the same time. Very good toughness. In this test, the polyurea prepared in Example 3 (only super-tough polyetheramine I), Example 4 (only super-tough polyetheramine II), and Example 5 (containing both super-tough polyetheramine I and II) The anti-corrosion coating is the test group, and the polyurea anti-corrosion coating without super-tough polyetheramine is the control group. The effect of super-tough polyether amine on the properties of polyurea anti-corrosion coating is tested. Under the conditions of a temperature of 25℃ and a relative humidity of 55%, each group takes 10 pieces of 120×50×0.28mm tinplate as the base material, and mixes the A component and the B component according to 1:2.5, press 0.25kg /㎡, use Graco polyurea spraying equipment HPX-3 spray, test the performance after 7 days of curing, the bending performance test takes the pass rate, and the other performance indicators take the best value. The test results are shown in the table below.

The bending performance test adopts ASTM D522 as the test standard, and the qualified index is: the diameter of the bending cylinder is 13mm, and the test piece coating should be free of peeling or cracking.

Table 2 The effect of super-tough polyetheramine on the properties of polyurea anticorrosive coatings

According to the data in Table 2, it can be seen that the adhesion, abrasion resistance, cathodic peeling resistance and impact strength of polyurea anticorrosive coatings containing both super-tough polyetheramine Ⅰ and Ⅱ are better than those of only super-tough polyetheramine Ⅰ or The polyurea anticorrosive coating of Ⅱ is better than the polyurea anticorrosive coating without super tough polyetheramine. At the same time, polyurea anticorrosive coatings containing super-tough polyetheramine I and II have the best bending performance, with a detection pass rate of 100%, while the pass rate of polyurea anticorrosive coatings without super-tough polyetheramine is only 50%. The addition of super-tough polyetheramine can also increase the high temperature resistance of the coating, so that the coating is not prone to bulging and falling off at a high temperature of 160°C. This shows that the addition of super-tough polyetheramine can increase the cross-linking density of anti-corrosion coatings, increase the rigidity of the coating, and at the same time increase the toughness, achieving the characteristics of "rigid and flexible", and the super-tough polyetheramine I and II It is better to match and add.

Effect Example 3

Effect of Trimethylolpropane Trimethacrylate on the Properties of Polyurea Anticorrosive Coatings

In this experiment, the polyurea anticorrosive coating prepared in Example 5 and Example 6 (adding trimethylolpropane trimethacrylate on the basis of Example 5) was used as the test group to detect trimethylolpropane trimethacrylate. Influence on the properties of polyurea anticorrosive coatings. Under the conditions of a temperature of 25℃ and a relative humidity of 55%, each group takes 10 pieces of 120×50×0.28mm tinplate as the base material, and mixes the A component and the B component according to 1:2.5, press 0.25kg /㎡, use Graco polyurea spraying equipment HPX-3 spray, test the performance after 7 days of curing, the bending performance test takes the pass rate, and the other performance indicators take the best value. The test results are shown in the table below.

Table 3 The effect of trimethylolpropane trimethacrylate on the properties of polyurea anticorrosive coatings

According to the comparison results in Table 3, it is found that on the basis of Example 5, the addition of trimethylolpropane trimethacrylate during the preparation process of component A can make the polyurea anticorrosive coating have stronger adhesion and better wear resistance. The pass rate of the bending performance test remains 100%, and the impact strength is basically unchanged. The addition of trimethylolpropane trimethacrylate, as a small molecular hydroxyl compound, increases the toughness and elasticity of the A component prepolymer, reduces the brittleness caused by excessively high crosslinking density, and ultimately enhances the polyurea anticorrosive coating The toughness of the coating increases the adhesion of the coating to the substrate, and the wear resistance is better.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: It is still possible to modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention range.

Claims

A rigid, high-temperature resistant polyurea anticorrosive coating, characterized in that the polyurea anticorrosive coating includes component A and component B, wherein component A includes the following raw materials by mass: 80-90 parts of polyisocyanate, 10-20 parts of polyester polyol; component B includes the following raw materials by mass: 10-30 parts of amino-terminated polyether, 10-30 parts of amino chain extender, 40-70 parts of super tough polyetheramine;

The polyisocyanate is selected from: polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenyl One or a combination of two or more of methyl methane diisocyanates;

The molecular weight of the polyester polyol is 2000-3500, the hydroxyl value is 360-400mg KOH/g, the acid value is ≤2.0mgKOH/g, the moisture content is ≤0.1%, and the viscosity is ≤4000mPa·s;

The amino-terminated polyether is a polyetheramine with a molecular weight of 2000-5000;

The amino chain extender is selected from one or a combination of two or more of diethyltoluenediamine, Ethancure-100, and dimethylthiotoluenediamine;

The super tough polyether amine is selected from polyether amines having 3 secondary amine caps.
The rigid, high-temperature resistant polyurea anticorrosive coating according to claim 1, wherein the structure of the ultra-tough polyetheramine is as follows:

and / or

among them,
n is an integer between 6-12,

m is an integer between 9-18.
The rigid, high-temperature resistant polyurea anticorrosive coating according to claim 2, wherein the preparation process of the super-tough polyetheramine of general formula I is as follows:

among them,
n is an integer between 6-12,

Specifically, compound 1 is added to the reactor, nitrogen is introduced, compound 2 is slowly added dropwise with stirring, the catalyst is added, and the reaction is stirred for 12-24 hours to obtain a super-tough polyetheramine of general formula I;

The catalyst is selected from one or a combination of two or more of zinc chloride, sodium ethoxide, sodium hydride, sodium amide, and organic alkali;

The preparation process of super tough polyetheramine of general formula II is as follows:

among them,
m is an integer between 9-18;

Specifically, 1-3 times the molar amount of epichlorohydrin was added to compound 3, reacted for 6-12 hours, and the alkali solution was added dropwise. After completion, the reaction was kept for 3-5 hours, and then distilled under reduced pressure, and 2 was added to the concentrated product. -Propylamine, at a temperature of 60-100°C, react for 5-10 hours to obtain a super tough polyetheramine of general formula II.
The rigid, high-temperature resistant polyurea anticorrosive coating according to any one of claims 1 to 3, wherein the A component further includes 3-7 parts of trimethylolpropane trimethacrylate.
The rigid, high-temperature resistant polyurea anticorrosive coating according to any one of claims 1-3, wherein the B component further includes 1-2 parts of leveling agent, 0.1-1 part of anti-ultraviolet agent, and 0.01 part of antioxidant. -1 part, 0.1-2 parts of pigment and filler or a combination of two or more.
A method for preparing rigid, high-temperature-resistant polyurea anticorrosive coating according to claim 1, characterized in that it comprises the following steps:

(1) Dehydration of polyester polyol: Dehydrate the polyester polyol at 110-120°C and a vacuum of -0.08 to -0.1Mpa for 2-3 hours, and then lower to room temperature for later use;

(2) Preparation of component A: Put the polymethylene polyphenyl polyisocyanate into the reactor, and when the temperature is raised to 45-50°C, slowly add the dehydrated polyester polyol prepared in step (1) for 1-1.5 hours After the dripping is completed, the temperature is raised to 80-90°C, the temperature is kept for 2-3 hours, and the NCO content is sampled. When the NCO content is 23.0-24.5%, it is reduced to room temperature, filtered, and sealed and stored under nitrogen.

(3) Preparation of component B: Put the amino-terminated polyether into a mixing tank, add super-tough polyetheramine and amino chain extender, stir at 400-500 rpm for 45-60 minutes, filter, and pack for use;

(4) Mix component A and component B in a weight ratio of 1:2-3 to obtain a rigid, high-temperature resistant polyurea anticorrosive coating.
The preparation method according to claim 6, wherein the step (2) further comprises adding trimethylolpropane trimethacrylate after the dripping of the dehydrated polyester polyol is completed, and stirring uniformly.
The preparation method according to claim 6, characterized in that, preferably, the step (3) further comprises adding one or two of a leveling agent, an anti-ultraviolet agent, an antioxidant, and pigments before filtering. Stir the above combination evenly.
An application of the rigid, high-temperature-resistant polyurea anticorrosive coating of claim 1 in the anticorrosion of metal or concrete surfaces that produce high temperatures.
The application according to claim 9, characterized in that the surface temperature of the metal or concrete is ≤160°C.