CN104031542A - Polyurethane (PU) on rust paint with self-repairing function and preparation method thereof - Google Patents

Abstract

The invention relates to a polyurethane rusty coating with self-repairing function and a preparation method thereof, belonging to the technical field of coatings. The polyurethane rust paint is composed of synthetic resin, molecular sieve, pigment, auxiliary agent, solvent, filler and curing agent. The preparation method is as follows: first synthesizing the aluminum phosphate molecular sieve, then modifying the aluminum phosphate molecular sieve with organic acid and inorganic acid, then carrying out coupling agent coating treatment, and finally preparing the polyurethane rust coating from the coated aluminum phosphate molecular sieve. The coating has controllable rust conversion ability and good self-healing ability to rust-free steel substrates, and can be widely used in rusty areas of power transmission equipment, bridges, ships, offshore platforms, harbor facilities, and outer walls of oil tanks, etc. painting.

Description

Polyurethane rust coating with self-repair function and preparation method thereof

technical field

The invention relates to a polyurethane rusty coating with self-repairing function and a preparation method thereof, belonging to the technical field of coatings.

Background technique

Power facilities are severely corroded in acid rain or coastal environments, requiring protective coatings with excellent performance for protection. Protective coatings for electric power have a certain service life according to the regulations of the electric power company, such as: 3 years or 5 years. When maintenance is carried out beyond the service life, it is often seen that some steel components have been severely corroded due to the failure of the surface coating. These rust layers must be removed during maintenance before repainting. For the angle steel structure of outdoor power poles and towers, it is difficult to remove the rust layer on the surface of the steel substrate due to the large number of edges and corners and the short maintenance time of power outages. If the rust layer is not completely removed, it will affect the bonding force between the coating and the steel substrate, which will shorten the service life of the coating and accelerate the corrosion of the electric steel structure.

The use of rusty coatings can solve the problems encountered in this practical project, but the performance of rusty coatings cannot meet the protection requirements of power facilities at present. Commonly used rust coatings mainly include three types: penetrating type, conversion type and stable type. For conversion-type rust coatings, since the main composition of the coating is phosphoric acid, excess phosphoric acid will affect the adhesion of the topcoat, resulting in premature failure of the coating. For the penetrating type, when the rust layer exceeds 0.5mm, it is difficult for the paint to penetrate into the interior of the coating. For stable coatings, when applied directly, the adhesion on the rust layer is obviously not as good as the steel substrate without rust layer, so the coating is easy to peel off.

Contents of the invention

Can not satisfy the requirement of power system for the existing rust coating, the object of the present invention is to provide a kind of polyurethane band rust coating with self-repair function and preparation method thereof, can prepare the coating with self-repair function, use coating for Corrosion of the surface of the metal substrate can improve the protective effect of the substrate.

Technical scheme of the present invention is:

A kind of polyurethane band rust paint with self-repair function, described polyurethane band rust paint is made of following two components:

In parts by mass, component one includes the following components and contents:

In parts by mass, component two includes the following components and contents:

Solvent 0~50;

Curing agent 50~100;

The mass ratio of component one to component two is (100:1)～(100:80);

Described molecular sieve is aluminum phosphate molecular sieve, effective aperture , particle size ≤ 325 mesh.

The molecular sieve is a modified molecular sieve treated with inorganic acid, organic acid or their mixture.

Described inorganic acid is polyphosphoric acid, such as: one or more mixtures of pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, pentapolyphosphoric acid, hexapolyphosphoric acid; described organic acid is tannic acid or Phytic acid.

The modified molecular sieve is a coated molecular sieve treated with a coupling agent coating.

The coupling agent is a silane coupling agent, and the silane coupling agent includes silane couplings such as vinyls, chlorocarbons, ammonia hydrocarbons, epoxy hydrocarbons, methacryloyloxyalkyls or sulfur-containing hydrocarbons. Agents, commercial brands such as: WD-26, A150, WD-50, KH550, WD-60, KH560, WD70 or KH570, etc.

Described synthetic resin is hydroxyl acrylic resin, hydroxyl polyester resin or their mixture, can be selected from Desmophen A365/1, Desmophen650, Desmophen651 or Desmophen A265 of Germany Bayer (Bayer), or be selected from New Pace resin (Suzhou) 2850, 1182, 1184 or 1196 for limited companies.

The curing agent is an isocyanate curing agent, which can be selected from CORONATE HX, CORONATE HX-T, CORONATE HXR or CORONATE HXLV of Nippon Polyurethane Industry Co., Ltd.

The solvent is an organic solvent commonly used in the preparation of polyurethane coatings, such as: toluene, xylene, butyl acetate, isobutyl acetate, methyl isopropyl ketone, methyl isobutyl ketone or methyl amyl ketone, etc. .

The coloring pigments are commonly used pigments in the preparation of polyurethane coatings, such as titanium dioxide, iron oxide red or iron oxide yellow, and the like.

The fillers are commonly used fillers in the preparation of polyurethane coatings, such as barite powder, china clay or talcum powder.

The auxiliary agent is an auxiliary agent often used in the coating preparation process, including anti-settling agent, wetting and dispersing agent or leveling agent, etc.;

The auxiliary agent is one or more of dispersants, defoamers, leveling agents and anti-settling agents commonly used in coatings. Dispersant, such as: Disperbyk-160, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-164, Disperbyk-166 or Disperbyk-170 from BYK Chemie, Germany. Defoamer, such as: 260DA, 9200DA, 150DA or AMAFCA of Taiwan Sanhua Industrial Co., Ltd. Leveling agent, such as: FLOW300 or FLOW ZFS460 of Tego Chemical Company (Tego). The anti-sedimentation agent uses organic bentonite, such as: JF-27, JF-3, BS-1A or BS-1C organic bentonite from Zhejiang Fenghong Clay Co., Ltd.

The present invention has the preparation method of the polyurethane band rust paint of self-repair function, and its process is as follows:

(1) Preparation of molecular sieve

The gel mixture was prepared by using pseudo-boehmite and orthophosphoric acid as sources of aluminum and phosphorus, and triethylamine as a template. The molar ratio of the gel mixture is 1.0 Al ₂ O ₃ : 1.0 P ₂ O ₅ : 1.5 triethylamine: xH ₂ O, x is the mole number of H ₂ O, x=90-800. Pseudoboehmite is first mixed with deionized water, and the mixed slurry is mechanically stirred in an autoclave for 10 to 15 hours, and then the mixture of orthophosphoric acid and deionized water is added to the mixed slurry, and the slurry becomes a viscous gel , After stirring for 1 to 3 hours, it becomes a flowing liquid. Then add triethylamine into the gel, stir for 1-5 hours, then put the gel into an autoclave and react at 180-220°C for 18-24 hours. The reacted solid is washed with deionized water, dried at 100-120°C for 5-10 hours, sintered at 500-600°C for 10-15 hours, ground and passed through a 325-mesh sieve to obtain an aluminum phosphate molecular sieve;

(2) Preparation of modified molecular sieve

First add deionized water into the reaction kettle, then add 5% to 50% of deionized water quality inorganic acid and organic acid or their mixture under stirring, stir at 500 to 1500rpm for 10 to 30 minutes; then add 5% to Molecular sieve with 20% deionized water quality, disperse at 500-1500rpm for 10-30 minutes; then vacuumize, keep in vacuum state for 5-15 hours, wash with deionized water after vacuuming, and then dry at 80-120°C for 5-15 hour, grinding, crossing 325 mesh sieves to obtain modified molecular sieves;

(3) Preparation of coated molecular sieves

Add the modified molecular sieve into the reaction kettle, and then add the mixed solvent of deionized water and ethanol (the mass ratio of deionized water to ethanol is (1:1)～(1 : 10)), then add 0.5% ~ 5% coupling agent of modified molecular sieve quality, stir at 500 ~ 1500rpm for 0.2 ~ 1 hour, heat up to 20 ~ 80 ° C, stir for 0.5 ~ 5 hours, finally the mixture is suction filtered, 80 Dry at ~120°C for 5-15 hours, grind, and pass through a 325-mesh sieve to obtain a coated molecular sieve;

(4) The above-mentioned coated molecular sieves are added into synthetic resins, auxiliary agents, pigments, fillers and solvents, dispersed and ground to obtain the polyurethane rust coating component 1;

(5) The curing agent is dissolved in a solvent to obtain component 2 of the polyurethane rust coating, which is added to component 1, and cured at room temperature for 1 to 7 days to form the polyurethane rust coating.

Advantage of the present invention and beneficial effect are:

1. The polyurethane rust coating of the present invention is composed of synthetic resin, specific modified and coated molecular sieves, pigments, additives, solvents, fillers and curing agents. The preparation method is as follows: first synthesizing the aluminum phosphate molecular sieve, then modifying the aluminum phosphate molecular sieve with organic acid and inorganic acid, then carrying out coupling agent coating treatment, and finally preparing the polyurethane rust coating from the coated aluminum phosphate molecular sieve. The coating has controllable rust conversion ability and good self-healing ability to rust-free steel substrates, and can be widely used in rusty areas of power transmission equipment, bridges, ships, offshore platforms, harbor facilities, and outer walls of oil tanks, etc. painting.

2. A modified and coated molecular sieve powder can be obtained by using the present invention. The coated molecular sieve has good dispersion and compatibility in polyurethane coatings, which solves the problem of easy coating damage caused by directly adding non-coated molecular sieves. Bubble problem. The method of using organic acid and/or inorganic acid to adsorb and assemble in the nanopores of molecular sieves solves the problem that directly adding polyphosphoric acid, phytic acid, and tannic acid to the coating will easily cause large-scale foaming of the coating. Polyphosphoric acid The slow release of phytic acid and tannin in the molecular sieve improves the transformation ability of the rust layer. Aluminum phosphate molecular sieve itself is also an excellent anti-corrosion pigment, which enhances the corrosion resistance of the coating; due to the phosphating effect of polyphosphoric acid on steel, phytic acid, tannin and steel are easy to form complexes, making the coating The layer has good self-healing function; the polyurethane rust coating has good storage stability.

3. The method of the present invention is applicable to the large-scale production of polyurethane rust coatings, and the product polyurethane rust coatings of the present invention can be widely used in the anti-corrosion construction of steel structure parts that are difficult to completely remove the rust layer.

Detailed ways

In a specific embodiment, the preparation method of the polyurethane rust coating with self-repairing function of the present invention, the process is as follows:

(1) Preparation of molecular sieve:

The gel mixture was prepared by using pseudo-boehmite and orthophosphoric acid as sources of aluminum and phosphorus, and triethylamine as a template. The molar ratio of the gel mixture is Al ₂ O ₃ : P ₂ O ₅ : 1.5 triethylamine: 120H ₂ O (that is, in terms of molar ratio, Al ₂ O ₃ : P ₂ O ₅ : triethylamine: H ₂ O = 1:1:1.5:120). Pseudoboehmite is first mixed with deionized water, and the mixed slurry is mechanically stirred in an autoclave for 12 hours, and then the mixed solution of orthophosphoric acid and deionized water is added to the mixed slurry, and the slurry becomes a viscous gel, stirred After 2 hours it became a mobile liquid. Then triethylamine was added to the gel, stirred for 3 hours, and then the gel was put into an autoclave at 205° C. for 20 hours. The reacted solid was washed with water six times, dried at 105°C for 6 hours, sintered at 560°C for 12 hours, ground and passed through a 325-mesh sieve to obtain an aluminum phosphate molecular sieve.

(2) Preparation of modified molecular sieve

First add 1000kg of deionized water to the reactor, then add 70kg of pyrophosphoric acid, 50kg of tannic acid, and 50kg of phytic acid under stirring, and stir at 1000rpm for 25 minutes; then add 100kg of molecular sieves and disperse at 1000rpm for 25 minutes; Keep it in a vacuum state for 7 hours, wash with deionized water after vacuuming, dry at 105°C for 6 hours, grind and pass through a 325 mesh sieve to obtain a modified aluminum phosphate molecular sieve.

(3) Preparation of coated molecular sieves

Add 10kg of modified molecular sieves to the reaction kettle, then add 300kg of mixed solvent of water and ethanol (the mass ratio of water to ethanol is 1:9) under stirring, then add 0.2kg of KH560 silane coupling agent, and stir at 1000rpm for 0.3 hours , heated up to 50°C, stirred for 1.5 hours, and finally the mixture was suction-filtered, dried at 105°C for 6 hours, ground, and passed through a 325-mesh sieve to obtain a coated aluminum phosphate molecular sieve;

(4) Preparation of polyurethane rust coating:

The above-mentioned coated molecular sieve is added to the synthetic resin, additives, pigments, fillers and solvents, dispersed and ground to obtain the polyurethane rust coating component 1;

The curing agent is dissolved with a solvent to obtain component 2 of the polyurethane rust coating, which is added to component 1 and cured at room temperature for 1 to 7 days to form the polyurethane rust coating.

The present invention will be further described in detail below through comparative examples, examples, salt spray experiments and stability observation of coatings.

Comparative example 1:

Add 62kg1196 resin into the reaction kettle, then add 0.5kg Disperbyk-166 dispersant, 0.5kg JF-27 anti-settling agent, 15kg methyl isobutyl ketone, 6kg non-modified and non-coated phosphoric acid under stirring Aluminum molecular sieve, 15kg titanium dioxide and 1kg talcum powder were stirred for 40 minutes, and then these resin mixtures were ground to obtain component 1 of polyurethane rust coating; in another reaction kettle, 50kg CORONATE HXR curing agent was dissolved in 50kg butyl acetate Component 2 of the polyurethane rust coating was prepared; the component 2 was added to the component 1 according to the mass ratio of component 1: component 2 = 100:22, and cured at room temperature for 7 days to form the polyurethane rust coating.

Comparative example 2

Put 62kg1196 resin in the reaction kettle, then add 0.5kg Disperbyk-166 dispersant, 0.5kg JF-27 anti-settling agent, 15kg methyl isobutyl ketone, 6kg modified aluminum phosphate molecular sieve (without coating treatment) under stirring state , 15kg titanium dioxide and 1kg talcum powder, stir for 40 minutes, and then grind these resin mixtures to obtain component 1 of polyurethane rust coating; dissolve 50kg CORONATE HXR curing agent in 50kg butyl acetate in another reaction kettle , to make component two of the polyurethane rust coating; according to the mass ratio of component one: component two = 100:22, the component two is added to the component one, and cured at room temperature for 7 days to form the polyurethane rust coating.

Example 1:

Add 62kg1196 resin in the reaction kettle, then add 0.5kg Disperbyk-166 dispersant, 0.5kg JF-27 anti-settling agent, 15kg methyl isobutyl ketone, 6kg coated aluminum phosphate molecular sieve, 15kg titanium dioxide and 1kg of talcum powder, stirred for 40 minutes, and then ground the resin mixture to obtain component 1 of polyurethane rust coating; in another reaction kettle, 50kg of CORONATE HXR curing agent was dissolved in 50kg of butyl acetate to make polyurethane tape Component 2 of the rust coating; add component 2 to component 1 according to the mass ratio of component 1: component 2 = 100:22, and cure at room temperature for 7 days to form a polyurethane rust coating.

Example 2:

Add 62kg1196 resin to the reaction kettle, then add 0.5kg Disperbyk-166 dispersant, 0.5kg JF-27 anti-settling agent, 19kg methyl isobutyl ketone, 2kg coated aluminum phosphate molecular sieve, 15kg titanium dioxide and 1kg of talcum powder, stirred for 40 minutes, and then ground the resin mixture to obtain component 1 of polyurethane rust coating; in another reaction kettle, 50kg of CORONATE HXR curing agent was dissolved in 50kg of butyl acetate to make polyurethane tape Component 2 of the rust coating; add component 2 to component 1 according to the mass ratio of component 1: component 2 = 100:22, and cure at room temperature for 7 days to form a polyurethane rust coating.

Example 3:

Add 62kg1196 resin in the reaction kettle, then add 0.5kg Disperbyk-166 dispersant, 0.5kg JF-27 anti-settling agent, 12kg methyl isobutyl ketone, 9kg coated aluminum phosphate molecular sieve, 15kg titanium dioxide and 1kg of talcum powder, stirred for 40 minutes, and then ground the resin mixture to obtain component 1 of polyurethane rust coating; in another reaction kettle, 50kg of CORONATE HXR curing agent was dissolved in 50kg of butyl acetate to make polyurethane tape Component 2 of the rust coating; add component 2 to component 1 according to the mass ratio of component 1: component 2 = 100:22, and cure at room temperature for 7 days to form a polyurethane rust coating.

Salt spray test:

The invention utilizes a salt spray test to evaluate the anticorrosion performance of the coating. The salt spray test is carried out according to the national standard GB/T1771-2007, and the continuous spray method is adopted. The solution is 5% NaCl (mass percentage) solution, and the test temperature is 35±2°C. Coating preparation Use the air spray method to spray the paint on the 150mm×75mm×3mm Q235 steel plate that has been exposed to the sun for 6 months to remove floating rust, dry it at room temperature for 7 days, seal the edge, and then conduct a 200-hour salt spray test. The dry film thickness of the coating is 150±5μm.

Coating Stability Observation:

After the components of the coating are prepared, they are sealed and stored at room temperature for 3 months, and the storage stability is observed.

Table 1 shows the results of coating salt spray test and coating storage stability. The foaming situation of the coating shows that adding the molecular sieve of the modification and coating treatment of the present invention in the coating can improve the molecular sieve more than adding the molecular sieve without modification and coating treatment, and the molecular sieve with only modification treatment and no coating treatment. The corrosion resistance of the coating, and the coating has better storage stability.

Table 1 coating salt spray resistance test and coating storage stability results

Comparative example 1 Comparative example 2 Example 1 Example 2 Example 3 Blistering area (%) 92 74 0 0 0 storage stability gelled gelled no gel no gel no gel

Claims (9)

1. a kind of polyurethane band rust paint with self-repair function, is characterized in that, described polyurethane band rust paint is made of following two components: In parts by mass, component one includes the following components and contents: In parts by mass, component two includes the following components and contents: Solvent 0~50; Curing agent 50~100; The mass ratio of component one to component two is (100:1)-(100:80). 2. the polyurethane band rust paint with self-repair function according to claim 1, is characterized in that, molecular sieve is aluminum phosphate molecular sieve, and effective aperture , particle size ≤ 325 mesh. 3. The polyurethane rust coating with self-repairing function according to claim 1 or 2, wherein the molecular sieve is a modified molecular sieve treated with an inorganic acid, an organic acid or a mixture thereof. 4. The polyurethane rust coating with self-repairing function according to claim 3, wherein the inorganic acid is polyphosphoric acid; the organic acid is tannin or phytic acid. 5. The polyurethane rust-bearing coating with self-repairing function according to claim 3, wherein the modified molecular sieve is a coated molecular sieve treated with a coupling agent coating. 6. The polyurethane rust coating with self-repairing function according to claim 5, characterized in that the coupling agent is a silane coupling agent. 7. The polyurethane rust coating with self-repairing function according to claim 1, wherein the synthetic resin is hydroxyacrylic resin, hydroxypolyester resin or their mixture. 8. The polyurethane rust coating with self-repairing function according to claim 1, wherein the curing agent is an isocyanate curing agent. 9. a preparation method of the polyurethane band rust paint with self-repair function claimed in claim 1, is characterized in that, carries out in following order and step: (1) Preparation of molecular sieve Pseudoboehmite and orthophosphoric acid were used as sources of aluminum and phosphorus, and triethylamine was used as a template to prepare a gel mixture; the molar ratio of the gel mixture was Al ₂ O ₃ : P ₂ O ₅ : 1.5 triethylamine: xH ₂ O, x is the number of moles of H ₂ O, x=90~800; Pseudoboehmite is first mixed with deionized water, and the mixed slurry is mechanically stirred in an autoclave for 10~15 hours, and then orthophosphoric acid is mixed with deionized water The mixed solution of ionic water is added to the mixed slurry, and the slurry becomes a viscous gel, which turns into a flowing liquid after stirring for 1 to 3 hours; then add triethylamine to the gel, stir for 1 to 5 hours, and then pour the gel The glue is placed in an autoclave and reacted at 180-220°C for 18-24 hours; the reacted solid is washed with deionized water, dried at 100-120°C for 5-10 hours, sintered at 500-600°C for 10-15 hours, and ground at 325 mesh sieve to obtain aluminum phosphate molecular sieve; (2) Preparation of modified molecular sieve First add deionized water into the reaction kettle, then add 5% to 50% of deionized water quality inorganic acid and organic acid or their mixture under stirring, stir at 500 to 1500rpm for 10 to 30 minutes; then add 5% to Molecular sieve with 20% deionized water quality, disperse at 500-1500rpm for 10-30 minutes; then vacuumize, keep in vacuum state for 5-15 hours, wash with deionized water after vacuuming, and then dry at 80-120°C for 5-15 hour, grinding, crossing 325 mesh sieves to obtain modified molecular sieves; (3) Preparation of coated molecular sieves Add the modified molecular sieve into the reaction kettle, and then add a mixed solvent of deionized water and ethanol with 20 to 40 times the quality of the modified molecular sieve under stirring. The mass ratio of deionized water to ethanol is (1:1)～(1 : 10), then add 0.5%～5% coupling agent of modified molecular sieve quality, stir at 500～1500rpm for 0.2～1 hour, heat up to 20～80°C, stir for 0.5～5 hours, finally the mixture is suction filtered, 80～ Dry at 120°C for 5-15 hours, grind, and pass through a 325-mesh sieve to obtain a coated molecular sieve; (4) The above-mentioned coated molecular sieves are added into synthetic resins, auxiliary agents, pigments, fillers and solvents, dispersed and ground to obtain the polyurethane rust coating component 1; (5) The curing agent is dissolved in a solvent to obtain component 2 of the polyurethane rust coating, which is added to component 1, and cured at room temperature for 1 to 7 days to form the polyurethane rust coating.