CN113429863A

CN113429863A - Polyamide-amine type water-based lignin-based epoxy anticorrosive paint and preparation method thereof

Info

Publication number: CN113429863A
Application number: CN202110388265.3A
Authority: CN
Inventors: 史立平; 王亚鑫; 谭伟民; 狄志刚; 雒新亮; 饶兴兴; 刘仲阳; 何毅; 郁飞
Original assignee: CNOOC Energy Technology and Services Ltd; CNOOC Changzhou EP Coating Co Ltd; CNOOC Changzhou Paint and Coatings Industry Research Institute Co Ltd
Current assignee: CNOOC Energy Technology and Services Ltd; CNOOC Changzhou EP Coating Co Ltd; CNOOC Changzhou Paint and Coatings Industry Research Institute Co Ltd
Priority date: 2021-04-10
Filing date: 2021-04-10
Publication date: 2021-09-24
Anticipated expiration: 2041-04-10
Also published as: CN113429863B

Abstract

The invention discloses a polyamide-amine type aqueous lignin-based epoxy anticorrosive paint and a preparation method thereof. The polyamide-amine type waterborne lignin-based epoxy anticorrosive paint is prepared from the following raw materials in parts by weight: 80-120 parts of polyamide-amine type water-based lignin-based epoxy emulsion, 10-20 parts of water-based closed isocyanate crosslinking agent, 0.08-0.2 part of dibutyltin dilaurate, 60-100 parts of water-based pigment and filler slurry, 0.2-0.6 part of defoaming agent, 0.1-0.6 part of flatting agent, 0.2-0.6 part of flash rust inhibitor and 0-10 parts of deionized water. The polyamide-amine type waterborne lignin-based epoxy anticorrosive coating prepared by the invention carries out relatively comprehensive molecular structure modification on matrix resin and a curing agent, the cross-linking structure of the coating is obviously changed, the cross-linking density of the prepared coating is greatly enhanced, the coating can resist high temperature of 250 ℃, and meanwhile, the coating has excellent strong acid or strong alkali resistance.

Description

Polyamide-amine type water-based lignin-based epoxy anticorrosive paint and preparation method thereof

Technical Field

The invention belongs to the field of anticorrosive coatings, and particularly relates to a polyamide-amine type aqueous lignin-based epoxy anticorrosive coating and a preparation method thereof.

Background

Most heavy anti-corrosion coatings used in the current market belong to solvent-based coatings, and Volatile Organic Compounds (VOC) contained in the heavy anti-corrosion coatings have high toxicity and flammability and are easy to threaten the atmosphere and human health. According to statistics, the organic solvent discharged into the atmosphere every year in the coating industry of China at present is about 100 million tons, which not only seriously pollutes the environment, but also wastes a large amount of resources. The water-based paint replaces an organic solvent in a solvent-based paint with water, has the greatest characteristic of greatly reducing the VOC content, achieves the aim of environmental protection, and is one of the main development trends of the existing anticorrosive paint. Countries and regions such as the United states, Japan, Europe and the like have started to widely popularize and use the water-based anticorrosive paint, the water-based anticorrosive paint accounts for more than 50 percent of the total anticorrosive paint, and China as a large country for producing and using the water-based anticorrosive paint only accounts for about 10 percent. Therefore, the development and application of high-performance water-based anticorrosive paint are imperative.

The water-based epoxy anticorrosive paint is a high-performance paint widely used for corrosion protection at present, and mainly comprises hydrophilic epoxy resin and a hydrophilic curing agent. As the epoxy resin contains special functional groups such as epoxy group and the like, compared with other waterborne anticorrosive coatings, the waterborne epoxy anticorrosive coating has good wear resistance and adhesion, can meet different construction requirements, and is applied to anticorrosive coating systems in large quantity. However, compared with the traditional solvent type epoxy anticorrosive paint, the water-based epoxy paint still has some defects, such as low crosslinking density of the paint, poor anticorrosive performance caused by insufficient sealing property on a substrate, and lower anticorrosive performance than that of a corresponding solvent paint; poor interlayer adhesion, high surface tension, easy occurrence of flash corrosion and the like. At present, the research on the waterborne epoxy anticorrosive paint focuses on the aspects of modification of epoxy resin, compatibility of the epoxy resin and a curing agent, application of pigments, fillers and auxiliaries, improvement of a production process of a waterborne epoxy resin emulsion and the like.

The application number 201811277499.5 describes a preparation method of a graphene-containing water-based epoxy anticorrosive paint, which comprises the steps of intercalating and oxidizing common natural crystalline flake graphite, dissolving the natural crystalline flake graphite in deionized water, ultrasonically stripping a lamellar layer to obtain a graphene oxide aqueous solution, adding graphene oxide serving as a filler into water-based epoxy resin, and adding an auxiliary agent to obtain the graphene-containing water-based epoxy composite paint.

The patent with the application number of 201910664126.1 discloses a water-based epoxy anticorrosive paint and a preparation method thereof, wherein the water-based epoxy anticorrosive paint consists of a component A and a component B, and the component A comprises water-based epoxy resin emulsion and siloxane modified nano SiO₂The coating comprises a dispersion liquid, a film forming auxiliary agent, a pigment, a filler, a dispersing agent, a defoaming agent, a substrate wetting agent, an anti-flash rust agent, an adhesion promoter and water; the component B consists of a curing agent and water; the mass ratio of the component A to the component B is (8.5-10): 1. the prepared water-based epoxy anticorrosive paint has the advantages of high drying speed, low VOC, good storage stability, convenient construction, low cost and the like, and the formed paint film has excellent water resistance, corrosion resistance and impact resistance.

The waterborne epoxy anticorrosive paint synthesized by the method cannot modify the molecular structure of matrix resin comprehensively, the cross-linking structure of the coating is not changed obviously, and the prepared coating has the problems of low cross-linking density, poor high-temperature resistance, poor strong acid or strong alkali resistance and the like.

Disclosure of Invention

Based on the above, the invention aims to provide a polyamide-amine type aqueous lignin-based epoxy anticorrosive coating and a preparation method thereof, wherein the polyamide-amine type aqueous lignin-based epoxy anticorrosive coating has good heat resistance and solvent resistance.

The polyamide-amine type waterborne lignin-based epoxy anticorrosive paint is prepared from the following raw materials in parts by weight: 80-120 parts of polyamide-amine type water-based lignin-based epoxy emulsion, 10-20 parts of water-based closed isocyanate crosslinking agent, 0.08-0.2 part of dibutyltin dilaurate, 60-100 parts of water-based pigment and filler slurry, 0.2-0.6 part of defoaming agent, 0.1-0.6 part of flatting agent, 0.2-0.6 part of flash rust inhibitor and 0-10 parts of deionized water.

In one embodiment, the water-based blocked isocyanate crosslinking agent is prepared from the following raw materials in parts by weight: the weight ratio of pentamethylene diisocyanate, dimethylolpropionic acid, trimethylolpropane, butanone, dibutyltin dilaurate, a sealing agent, triethylamine and deionized water is (220-320): (13-25): (55-80): (35-80): (0.06-0.38): (120-170): (11-15): (100-140);

in one embodiment, in the polyamide-amine aqueous lignin-based epoxy emulsion, the weight ratio of lignin, epoxy resin, propylene glycol methyl ether, 1.0 generation hydroxyl-terminated polyamide-amine resin, an emulsifier CTW-6060 and deionized water is (80-120): (800-1200): (200-300): (40-70): (140-180): (800-1200).

In one embodiment, the defoaming agent is any one or more of 901W, BYK-022 or BYK-019, the leveling agent is any one or two of RM-2020 or BYK-346, and the anti-flash rust agent is any one or more of Roybo 60, sodium nitrite or Clariant-AC 18.

The invention also provides a preparation method of the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint, which is characterized by comprising the following steps of:

1) adding pentamethylene diisocyanate, dimethylolpropionic acid, trimethylolpropane, butanone and dibutyltin dilaurate into a reactor, reacting for 2-6 h at 50-80 ℃, adding a sealing agent, continuing to react for 2-6 h, cooling to 40-60 ℃, adding triethylamine, reacting for 0.5-1 h, adding deionized water under high-speed stirring, and distilling under reduced pressure to remove butanone to obtain a water-based closed isocyanate crosslinking agent;

2) adding lignin, epoxy resin, ethylene glycol monomethyl ether and 1.0 generation hydroxyl-terminated polyamide-amine resin into a reactor, reacting for 1-5 h at 90-120 ℃, adding an emulsifier CTW-6060, stirring for 1-5 h at 90-120 ℃, and then adding deionized water under the stirring condition of a high-speed dispersion machine to obtain a polyamide-amine type aqueous lignin-based epoxy emulsion;

3) sequentially adding deionized water, a dispersing agent, a wetting agent, titanium dioxide, carbon black, zinc phosphate, mica powder, talcum powder, silicon carbide and barium sulfate into a proportioning cylinder, uniformly stirring, grinding and dispersing until the fineness of a scraper is less than 20 mu m, standing for defoaming, filtering and discharging to obtain water-based pigment and filler slurry;

4) sequentially adding the polyamide-amine type aqueous lignin-based epoxy emulsion prepared in the step 2), the aqueous closed isocyanate crosslinking agent prepared in the step 1) and dibutyltin dilaurate into a proportioning cylinder, uniformly stirring at a high speed, adding the aqueous pigment slurry prepared in the step 3) into the proportioning cylinder in the stirring process, continuously adding a defoaming agent, a flatting agent and an anti-flash rust agent under the stirring state, uniformly dispersing, finally adding deionized water, and uniformly stirring to obtain the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint;

wherein the polyamide-amine type aqueous lignin-based epoxy emulsion, the aqueous blocked isocyanate crosslinking agent, dibutyltin dilaurate, the aqueous pigment slurry, the defoaming agent, the flatting agent, the anti-flash rust agent and the deionized water are in a weight ratio of (80-120): (10-20): (0.08-0.2): (60-100): (0.2-0.6): (0.1-0.6): (0.2-0.6): (0-10).

In one embodiment, in the step 1), weight ratios of pentamethylene diisocyanate, dimethylolpropionic acid, trimethylolpropane, butanone, dibutyltin dilaurate, a blocking agent, triethylamine and deionized water are (220-320): (13-25): (55-80): (35-80): (0.06-0.38): (120-170): (11-15): (100-140).

In one embodiment, in the step 2), the weight ratio of the lignin, the epoxy resin, the propylene glycol methyl ether, the 1.0-substituted hydroxyl-terminated polyamide-amine resin, the emulsifier CTW-6060 and the deionized water is (80-120): (800-1200): (200-300): (40-70): (140-180): (800-1200).

In one embodiment, in step 1), the blocking agent is at least one of imidazole, 2-methylimidazole and 3, 5-dimethylpyrazole.

In one embodiment, in step 2), the epoxy resin is at least one of epoxy resin E12 and epoxy resin E20.

In one embodiment, in the step 4), the defoaming agent is any one or more of 901W, BYK-022 or BYK-019, the leveling agent is any one or two of RM-2020 or BYK-346, and the flash rust inhibitor is any one or more of Roybo 60, sodium nitrite or Clariant-AC 18.

Compared with the traditional process technology, the invention has the following beneficial effects:

according to the polyamide-amine type aqueous lignin-based epoxy anticorrosive coating provided by the invention, lignin is directly compounded on epoxy resin through an in-situ reaction to obtain a lignin-based epoxy emulsion, on one hand, the lignin is a renewable and biodegradable resource with abundant reserves, the lignin is fully utilized, the consumption of petroleum resources can be reduced, and on the other hand, the unique phenol structure of lignin molecules and the phenolic hydroxyl and alcoholic hydroxyl with reaction activity can be used as hydroxyl components to participate in a crosslinking reaction, so that the heat resistance and solvent resistance of a system can be improved.

According to the polyamide-amine waterborne lignin-based epoxy anticorrosive paint provided by the invention, hydroxyl-terminated polyamide-amine resin is introduced into a system, and because the molecular structure of the polyamide-amine waterborne lignin-based epoxy anticorrosive paint contains more hydroxyl groups, the polyamide-amine waterborne lignin-based epoxy anticorrosive paint can participate in the crosslinking action of the system in multiple dimensions, the crosslinking structure of a coating is changed, the crosslinking density of the system is improved, and the chemical medium resistance of a coating film is further improved.

The polyamide-amine type aqueous lignin-based epoxy anticorrosive paint provided by the invention adopts an epoxy resin and isocyanate curing system, self-made blocked isocyanate can not only be subjected to cross-linking reaction with hydroxyl in the epoxy resin to form an interpenetrating network, the cured paint film has good physical and mechanical properties (especially the toughness of the paint film) and chemical medium resistance (especially the acid resistance and the alkali resistance of the paint film), the isocyanate can also be subjected to reaction with the epoxy group in the epoxy resin to generate an oxazolidone structure, so that the paint film has good heat resistance, and the paint prepared by the system also has excellent coating leveling property and weather resistance.

Drawings

FIG. 1 is an appearance of a sample of example 1 of the present invention after 20 days of immersion in a 20% hydrochloric acid solution.

FIG. 2 is a graph showing the appearance of a sample of comparative example 1 of the present invention after 20 days of immersion in a 20% hydrochloric acid solution.

Detailed Description

The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the embodiments.

Example 1

1) 277.2g of pentamethylene diisocyanate, 18g of dimethylolpropionic acid, 68g of trimethylolpropane, 47g of butanone and 0.19g of dibutyltin dilaurate are added into a four-neck flask provided with a spherical condenser tube, a nitrogen inlet tube, a stirrer and a thermometer, the mixture is reacted for 3 hours at 70 ℃, 140.76g of imidazole is added for further reaction for 3 hours, 13.56g of triethylamine is added at 50 ℃ for reaction for 1 hour, 117.45 g of deionized water is added under high-speed stirring, and butanone is removed through reduced pressure distillation, so that the water-based blocked isocyanate crosslinking agent is obtained.

2) 100g of lignin, 1000g of epoxy resin E-20, 300g of ethylene glycol monomethyl ether and 50g of 1.0 generation hydroxyl-terminated polyamide-amine resin are added into a four-neck flask provided with a spherical condenser pipe, a stirrer and a thermometer, the mixture reacts for 4 hours at 90 ℃, 150g of emulsifier CTW-6060 is added, the mixture is stirred for 1 hour at 100 ℃, and then 1000g of deionized water is added under the stirring condition of a high-speed dispersion machine, so that the polyamide-amine type aqueous lignin-based epoxy emulsion is obtained.

3) Adding 45.1g of deionized water, 12.6g of dispersing agent, 0.5g of wetting agent, 51.0g of titanium dioxide, 22g of carbon black, 6.6g of zinc phosphate, 10.0g of mica powder, 14.6g of talcum powder, 7g of silicon carbide and 7.6g of barium sulfate into a proportioning cylinder in sequence, uniformly stirring, grinding and dispersing until the fineness of a scraper is below 20 mu m, standing for defoaming, filtering and discharging to obtain the water-based pigment and filler slurry.

4) And (2) sequentially adding 100g of the polyamide-amine type aqueous lignin-based epoxy emulsion prepared in the step 2), 12.2g of the aqueous blocked isocyanate crosslinking agent prepared in the step 1) and 0.1g of dibutyltin dilaurate into a proportioning cylinder, uniformly stirring at a high speed, adding 85g of the aqueous pigment slurry prepared in the step 3) into the proportioning cylinder in the stirring process, continuously adding 0.3g of a defoaming agent 901W, 0.4g of a flatting agent BYK-346 and 0.4g of an anti-flash rust agent Raybo 60 into the proportioning cylinder in a stirring state, uniformly dispersing, finally adding 5g of deionized water, and uniformly stirring to obtain the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint.

Example 2

1) 277.2g of pentamethylene diisocyanate, 18g of dimethylolpropionic acid, 68g of trimethylolpropane, 47g of butanone and 0.19g of dibutyltin dilaurate are added into a four-neck flask provided with a spherical condenser tube, a nitrogen inlet tube, a stirrer and a thermometer, the mixture is reacted for 4 hours at 70 ℃, 149.76g of 2-methylimidazole is added and the reaction is continued for 3 hours, 13.56g of triethylamine is added at 50 ℃ and the reaction is continued for 1 hour, 117.45 g of deionized water is added under high-speed stirring, and the butanone is removed through reduced pressure distillation, so that the water-based blocked isocyanate crosslinking agent is obtained.

2) 150g of lignin, 1000g of epoxy resin E-20, 300g of ethylene glycol monomethyl ether and 50g of 1.0 generation hydroxyl-terminated polyamide-amine resin are added into a four-neck flask provided with a spherical condenser pipe, a stirrer and a thermometer, the mixture reacts for 1h at 120 ℃, 160g of emulsifier CTW-6060 is added, the mixture is stirred for 1h at 100 ℃, and then 1000g of deionized water is added under the stirring condition of a high-speed dispersion machine to obtain the polyamide-amine type aqueous lignin-based epoxy emulsion.

3) Adding 45.1g of deionized water, 14.6g of dispersing agent, 0.5g of wetting agent, 55.0g of titanium dioxide, 22g of carbon black, 6.6g of zinc phosphate, 10.0g of mica powder, 14.6g of talcum powder, 7g of silicon carbide and 7.6g of barium sulfate into a proportioning cylinder in sequence, uniformly stirring, grinding and dispersing until the fineness of a scraper is below 20 mu m, standing for defoaming, filtering and discharging to obtain the water-based pigment and filler slurry.

4) And (2) sequentially adding 100g of the polyamide-amine type aqueous lignin-based epoxy emulsion prepared in the step 2), 15.2g of the aqueous blocked isocyanate crosslinking agent prepared in the step 1) and 0.08g of dibutyltin dilaurate into a proportioning cylinder, uniformly stirring at a high speed, adding 85g of the aqueous pigment slurry prepared in the step 3) into the proportioning cylinder in the stirring process, continuously adding 0.3g of a defoaming agent 901W, 0.4g of a flatting agent BYK-346 and 0.4g of an anti-flash rust agent Raybo 60 into the proportioning cylinder in a stirring state, uniformly dispersing, finally adding 5g of deionized water, and uniformly stirring to obtain the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint.

Example 3

1) 297.2g of pentamethylene diisocyanate, 18g of dimethylolpropionic acid, 68g of trimethylolpropane, 67g of butanone and 0.19g of dibutyltin dilaurate are added into a four-neck flask provided with a spherical condenser tube, a nitrogen inlet tube, a stirrer and a thermometer, the mixture is reacted for 3 hours at 70 ℃, 140.76g of 3, 5-dimethylpyrazole is added for further reaction for 3 hours, 13.56g of triethylamine is added at 50 ℃, the reaction is carried out for 1 hour, 117.45 g of deionized water is added under high-speed stirring, and the butanone is removed through reduced pressure distillation, so that the water-based closed isocyanate crosslinking agent is obtained.

2) Adding 130g of lignin, 1000g of epoxy resin E-12, 300g of ethylene glycol monomethyl ether and 60g of 1.0 generation hydroxyl-terminated polyamide-amine resin into a four-neck flask provided with a spherical condenser pipe, a stirrer and a thermometer, reacting for 3 hours at 100 ℃, adding 150g of emulsifier CTW-6060, stirring for 1 hour at 100 ℃, and then adding 1000g of deionized water under the stirring condition of a high-speed dispersion machine to obtain the polyamide-amine type aqueous lignin-based epoxy emulsion.

3) Adding 55.1g of deionized water, 12.6g of dispersing agent, 0.5g of wetting agent, 51.0g of titanium dioxide, 22g of carbon black, 6.6g of zinc phosphate, 10.0g of mica powder, 14.6g of talcum powder, 7g of silicon carbide and 7.6g of barium sulfate into a proportioning cylinder in sequence, uniformly stirring, grinding and dispersing until the fineness of a scraper is below 20 mu m, standing for defoaming, filtering and discharging to obtain the water-based pigment and filler slurry.

4) And (2) sequentially adding 100g of the polyamide-amine type aqueous lignin-based epoxy emulsion prepared in the step 2), 12.2g of the aqueous blocked isocyanate crosslinking agent prepared in the step 1) and 0.1g of dibutyltin dilaurate into a proportioning cylinder, uniformly stirring at a high speed, adding 90g of the aqueous pigment slurry prepared in the step 3) into the proportioning cylinder in the stirring process, continuously adding 0.3g of a defoaming agent BYK-022, 0.4g of a flatting agent BYK-346 and 0.4g of an anti-flash rust agent Raybo 60 into the proportioning cylinder in a stirring state, uniformly dispersing, finally adding 5g of deionized water, and uniformly stirring to obtain the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint.

Example 4

1) 277.2g of pentamethylene diisocyanate, 18g of dimethylolpropionic acid, 68g of trimethylolpropane, 47g of butanone and 0.19g of dibutyltin dilaurate are added into a four-neck flask provided with a spherical condenser tube, a nitrogen inlet tube, a stirrer and a thermometer, the mixture is reacted for 3 hours at 70 ℃, 140.76g of imidazole is added for further reaction for 3 hours, 13.56g of triethylamine is added at 60 ℃ for reaction for 0.5 hour, 117.45 g of deionized water is added under high-speed stirring, and butanone is removed through reduced pressure distillation, so that the water-based closed isocyanate crosslinking agent is obtained.

2) 100g of lignin, 1000g of epoxy resin E-20, 200g of ethylene glycol monomethyl ether and 50g of 1.0 generation hydroxyl-terminated polyamide-amine resin are added into a four-neck flask provided with a spherical condenser pipe, a stirrer and a thermometer, the mixture reacts for 2 hours at 120 ℃, 150g of emulsifier CTW-6060 is added, the mixture is stirred for 1 hour at 100 ℃, and then 1000g of deionized water is added under the stirring condition of a high-speed dispersion machine, so that the polyamide-amine type aqueous lignin-based epoxy emulsion is obtained.

3) Adding 45.1g of deionized water, 12.6g of dispersing agent, 0.5g of wetting agent, 51.0g of titanium dioxide, 30g of carbon black, 6.6g of zinc phosphate, 10.0g of mica powder, 14.6g of talcum powder, 7g of silicon carbide and 7.6g of barium sulfate into a proportioning cylinder in sequence, uniformly stirring, grinding and dispersing until the fineness of a scraper is below 20 mu m, standing for defoaming, filtering and discharging to obtain the water-based pigment and filler slurry.

4) Sequentially adding 100g of the polyamide-amine type aqueous lignin-based epoxy emulsion prepared in the step 2), 12.2g of the aqueous blocked isocyanate crosslinking agent prepared in the step 1) and 0.1g of dibutyltin dilaurate into a proportioning cylinder, uniformly stirring at a high speed, adding 65g of the aqueous pigment slurry prepared in the step 3) into the proportioning cylinder during stirring, continuously adding 0.3g of a defoaming agent 901W, 0.3g of a leveling agent RM-2020 and 0.3g of an anti-flash rust agent Clariant-AC18 into the proportioning cylinder under stirring, uniformly dispersing, finally adding 5g of deionized water, and uniformly stirring to obtain the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint.

Comparative example 1

1) 277.2g of hexamethylene diisocyanate, 18g of dimethylolpropionic acid, 68g of trimethylolpropane, 47g of butanone and 0.19g of dibutyltin dilaurate are added into a four-neck flask provided with a spherical condenser tube, a nitrogen inlet tube, a stirrer and a thermometer, the mixture is reacted for 3 hours at 70 ℃, 140.76g of imidazole is added for further reaction for 3 hours, 13.56g of triethylamine is added at 50 ℃ for reaction for 1 hour, 117.45 g of deionized water is added under high-speed stirring, and butanone is removed through reduced pressure distillation, so that the water-based blocked isocyanate crosslinking agent is obtained.

2) Adding 1000g of epoxy resin E-20 and 300g of ethylene glycol monomethyl ether into a four-neck flask provided with a spherical condenser pipe, a stirrer and a thermometer, reacting for 3h at 90 ℃, adding 150g of emulsifier CTW-6060, stirring for 1h at 100 ℃, and then adding 1000g of deionized water under the stirring condition of a high-speed dispersion machine to obtain the polyamide-amine type waterborne lignin-based epoxy emulsion.

4) And (2) sequentially adding 100g of the water-based epoxy emulsion prepared in the step 2), 12.2g of the water-based closed isocyanate crosslinking agent prepared in the step 1) and 0.1g of dibutyltin dilaurate into a proportioning cylinder, uniformly stirring at a high speed, adding 85g of the water-based pigment slurry prepared in the step 3) into the proportioning cylinder in the stirring process, continuously adding 0.3g of a defoaming agent 901W, 0.4g of a flatting agent BYK-346 and 0.4g of an anti-flash rust agent Raybo 60 into the proportioning cylinder in a stirring state, uniformly dispersing, finally adding 5g of deionized water, and uniformly stirring to obtain the water-based epoxy anticorrosive paint.

Film coating Performance measurement

The coatings of examples 1 to 4 and the coating of comparative example 1 were respectively coated on a substrate and baked at 160 ℃ for 30min to prepare the coating films of examples 1 to 4 and comparative example 1. The obtained coating films were subjected to measurements of properties such as pencil hardness, adhesion, flexibility and dry heat resistance, and the results are shown in table 1.

The results of comparing the coating properties of the coatings prepared in examples 1 to 4 with those of the coating of comparative example 1 are shown in Table 1.

TABLE 1 results of film Performance test of examples 1 to 4 and comparative example 1

Item	Example 1	Example 2	Example 3	Example 4	Comparative example 1
						Appearance of the product	Is flat and smooth	Is flat and smooth	Is flat and smooth	Is flat and smooth	Is flat and smooth
Adhesion/grade	1	1	1	1	1
						Impact strength/cm	50	40	50	50	40
hardness/H	6H	6H	6H	6H	5H
						Flexibility/mm	1	1	1	2	2
Resistant dry heat (250 ℃, 72 h)	No damage and no light loss of the coating	No damage and no light loss of the coating	No damage and no light loss of the coating	No damage and no light loss of the coating	Cracking of the coating
						Salt spray resistance per hour	2000h	2010h	1900h	2100h	1500h
Resistant running water	No abnormal condition for 360 days	No abnormal condition for 360 days	No abnormal condition for 360 days	No abnormal condition for 360 days	No abnormal condition in 250 days
						Resistance to 20% HCl	No abnormal condition for 30 days	No abnormal condition for 30 days	No abnormal condition for 30 days	No abnormal condition for 30 days	No abnormal condition after 20 days
Resisting 20% NaOH	No abnormal condition for 30 days	No abnormal condition for 30 days	No abnormal condition for 30 days	No abnormal condition for 30 days	No abnormal condition for 15 days

TABLE 2 coating Change for 20 days of acid soak resistance of two waterborne coatings

Item	Example 1	Comparative example 1
			Hardness of pencil	5H	HB
Color difference (Delta E)	2.29	9.79
			Color difference (Delta L)	1.7	9.3

As can be seen from Table 1, compared with the coating film of the comparative example 1, the chemical resistance, the high temperature resistance, the corrosion resistance and the mechanical property of the waterborne epoxy anticorrosive coating prepared in the embodiments 1 to 4 of the invention are far better than those of the comparative example 1.

Comparing fig. 1 with fig. 2, the coating of comparative example 1 was significantly whitened in the soaked portion after 20 days of soaking in 20% HCl, due to the lower crosslink density of the coating, compared to example 1. From table 2, it is found that the hardness of the coating is reduced after the coatings of comparative example 1 and example 1 are soaked in acid resistance for 20 days, but the hardness of the coating is reduced most obviously in comparative example 1, and the color difference of comparative example 1 is changed greatly and the color change of the coating is most obvious. Therefore, the waterborne anticorrosive coating prepared by the invention has the advantages that the cross-linking structure of the coating is obviously changed by carrying out more comprehensive molecular structure modification on the matrix resin, and the prepared coating has high cross-linking density, good strong acid or strong alkali resistance and excellent high temperature resistance.

As noted above, while the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limited thereto. Various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The polyamide-amine type water-based lignin-based epoxy anticorrosive paint is characterized by comprising the following raw materials in parts by weight: 80-120 parts of polyamide-amine type water-based lignin-based epoxy emulsion, 10-20 parts of water-based closed isocyanate crosslinking agent, 0.08-0.2 part of dibutyltin dilaurate, 60-100 parts of water-based pigment and filler slurry, 0.2-0.6 part of defoaming agent, 0.1-0.6 part of flatting agent, 0.2-0.6 part of flash rust inhibitor and 0-10 parts of deionized water.

2. The polyamide-amine type aqueous lignin-based epoxy anticorrosive coating as claimed in claim 1, wherein the aqueous blocked isocyanate crosslinking agent is prepared from the following raw materials in parts by weight: the weight ratio of pentamethylene diisocyanate, dimethylolpropionic acid, trimethylolpropane, butanone, dibutyltin dilaurate, a sealing agent, triethylamine and deionized water is (220-320): (13-25): (55-80): (35-80): (0.06-0.38): (120-170): (11-15): (100-140).

3. The polyamide-amine type aqueous lignin-based epoxy anticorrosive paint as claimed in claim 1, wherein in the polyamide-amine type aqueous lignin-based epoxy emulsion, the weight ratio of lignin, epoxy resin, propylene glycol methyl ether, 1.0 generation hydroxyl-terminated polyamide-amine type resin, emulsifier CTW-6060 and deionized water is (80-120): (800-1200): (200-300): (40-70): (140-180): (800-1200).

4. The polyamidoamine-based waterborne lignin-based epoxy anticorrosive coating according to claim 1, wherein the defoamer is any one or more of 901W, BYK-022 or BYK-019, the leveling agent is any one or two of RM-2020 or BYK-346, and the flash rust inhibitor is any one or more of Roybo 60, sodium nitrite or Clariant-AC 18.

5. The preparation method of the polyamide-amine type aqueous lignin-based epoxy anticorrosive paint is characterized by comprising the following steps of:

6. The preparation method according to claim 5, wherein in the step 1), the weight ratio of pentamethylene diisocyanate, dimethylolpropionic acid, trimethylolpropane, butanone, dibutyltin dilaurate, a sealing agent, triethylamine and deionized water is (220-320): (13-25): (55-80): (35-80): (0.06-0.38): (120-170): (11-15): (100-140).

7. The preparation method according to claim 5, wherein in the step 2), the weight ratio of the lignin, the epoxy resin, the propylene glycol methyl ether, the 1.0-generation hydroxyl-terminated polyamide-amine resin, the emulsifier CTW-6060 and the deionized water is (80-120): (800-1200): (200-300): (40-70): (140-180): (800-1200).

8. The method according to claim 5, wherein in the step 1), the blocking agent is at least one of imidazole, 2-methylimidazole, and 3, 5-dimethylpyrazole.

9. The preparation method according to claim 5, wherein in the step 2), the epoxy resin is at least one of epoxy resin E12 and epoxy resin E20.

10. The preparation method according to claim 5, wherein in the step 4), the defoaming agent is any one or more of 901W, BYK-022 or BYK-019, the leveling agent is any one or two of RM-2020 or BYK-346, and the flash rust inhibitor is any one or more of Roybo 60, sodium nitrite or Clariant-AC 18.