CN112724792A

CN112724792A - Vehicle epoxy primer with excellent corrosion resistance and preparation method thereof

Info

Publication number: CN112724792A
Application number: CN202110106962.5A
Authority: CN
Inventors: 陈频
Original assignee: Nanjing Zircon New Material Technology Co ltd
Current assignee: Nanjing Zircon New Material Technology Co ltd
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2021-04-30

Abstract

The invention relates to the technical field of epoxy primer for vehicles, in particular to an epoxy primer for vehicles with excellent corrosion resistance, which comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises 45-55% of ionized water, epoxy resin, pigment slurry (the proportion ranges from 4:1 to 7: 1), 10% of sulfamic acid solution and graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.05-0.2), the graphene dispersion slurry comprises graphene, oligomer polyol, KH550 coupling agent (0.1-0.5%), and ethylene glycol monobutyl ether (1-5%) Good film forming property, high emulsion stability and excellent salt spray resistance.

Description

Vehicle epoxy primer with excellent corrosion resistance and preparation method thereof

Technical Field

The invention relates to the technical field of epoxy primer for vehicles, in particular to an epoxy primer for vehicles with excellent corrosion resistance and a preparation method thereof.

Background

According to the report of the Transparency Market Research organization, the income of the global automobile paint Market in 2017 is 195.3 billion dollars, and the composite annual average growth rate of the Market is expected to expand to 6.28% in the forecast period from 2018 to 2026, and the automobile paint Market reaches 336.3 billion dollars by 2026. According to mark Research Future, 2017, the primer portion covers 42% of the entire automotive coating application, where the sum of the varnish portion and the electrophoretic portion is roughly equivalent. One report by RL company indicates that the global automobile coating market (refinish paint, parts, Original Equipment Manufacturer (OEM)) share is about 224 billion euros ($ 253 billion), with the OEM coating share being 43% maximum. The part coating was about 20% and the refinish paint was about 37%. Global automotive paint sales are growing due to increased automobile production and "strong" growth in the automotive industry in korea, india, mexico, china, and brazil, among other countries. Manufacturers are turning to non-toxic and environmentally friendly products according to persistent market research. According to the academy of chemical sciences coating institute data, the OEM coating market for passenger cars (including SUVs, MPVs, and cars) in 2013 is about 36 million tons, accounting for about half of the coating market for passenger cars in china. It is predicted that the OEM coating market will grow at some point 7-8% per year. The growth of the automotive coating industry in China is driven by the continuous growth of the automotive industry, and the automotive industry in China has 1.1 million passenger cars by the end of 2013.

Although the research and development of the environment-friendly paint in China are relatively late, the performance of the water-based automobile paint is rapidly improved through years of research. The water-soluble paint is prepared by using water-soluble resin as a film forming material base material, and the water-soluble resin is dissolved into solution by water due to hydrophilicity. Epoxy electrophoretic primers are one of the most important, and electrophoretic primer coating is performed in all automobile coating processes. The purpose is to form an anticorrosive coating together with pretreatment. With the pressure of cost and the requirement of environmental protection, automobile manufacturers always want the epoxy electrophoretic primer to be as thin as possible, but the epoxy electrophoretic primer can affect the corrosion resistance, so that the epoxy primer for the automobile and the preparation method thereof are provided.

Disclosure of Invention

The invention aims to provide an epoxy primer for a vehicle with excellent corrosion resistance and a preparation method thereof, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: an epoxy primer with excellent corrosion resistance for a vehicle comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises ionized water (45% -55%), epoxy resin, pigment slurry (the ratio is in a range from 4:1 to 7: 1), 10% of sulfamic acid solution and graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.05-0.2), and the graphene dispersion slurry comprises graphene, oligomer polyol, KH550 coupling agent (0.1-0.5%) and ethylene glycol monobutyl ether (1% -5%).

Preferably, the graphene has 2 to 10 layers of a sheet structure.

Preferably, the oligomer polyol has a concentration range of 10-50% w/v by mass/volume, and the polyol is a compound material.

Preferably, the pH of the epoxy resin electrophoretic paint liquid is adjusted to about 5.5-6.0 by using a pH meter, and the pH is adjusted by using 10% of amino sulfonic acid solution.

Preferably, the graphene dispersion slurry is dripped into the electrophoretic paint in the treatment process at a speed of 5-10 drops per minute, and the agglomerated particles without the graphene slurry are filtered by a 1000-mesh nylon filter screen.

A preparation method of an epoxy primer for vehicles with excellent corrosion resistance comprises the following steps:

the method comprises the following steps: preparing graphene (graphene oxide) dispersion slurry, wherein 10 g of graphene (graphene oxide) can be prepared by an oxidation-reduction method, an intercalation stripping method or an in-situ deposition method in the prior art;

step two: dispersing graphene in 100 ml of oligomer polyol, adding a small amount of KH550 coupling agent and butyl cellosolve, and stirring at a high speed for about 1-6 hours until the graphene is uniformly dispersed without precipitation and agglomeration to prepare graphene dispersion slurry;

step three: preparing an epoxy electrophoretic paint coating, weighing 0.844 kg of deionized water, 1.8034 kg of epoxy resin and 0.1722 kg of pigment slurry, firstly adding the deionized water into a 2L beaker, then slowly adding the weighed epoxy resin, and uniformly stirring for about 10-20 minutes;

step four: slowly adding the pigment slurry while stirring the resin, adjusting the pH of the epoxy resin electrophoretic paint liquid by using a pH meter after uniformly stirring, adjusting the pH by using 10% of amino sulfonic acid solution, then stirring for about 6-12h (stirring speed: 800-;

step five: taking graphene dispersion slurry, stirring the electrophoretic paint by a cantilever type electric stirrer (stirring speed: 800 r/m), adding dropwise, stirring for about 6-12h under the cantilever type electric stirrer, and filtering agglomerated particles without the graphene slurry by a 1000-mesh nylon filter screen to prepare the epoxy resin electrophoretic paint;

step six: cleaning a standard phosphatized plate to be used with distilled water, putting the standard phosphatized plate into an oven at 180 ℃ for drying, putting the dried phosphatized plate into electrophoretic paint at the temperature of 32 ℃, clicking a start button on an electrophoretic power supply, recording a current curve and a voltage curve, and taking out after waiting for 180 s;

step seven: and (3) rapidly washing the electrophoretic solution on the plate by using high-pressure water, then cleaning the electrophoretic plate by using deionized water, then inverting and airing the electrophoretic phosphatized plate for a period of time, and then putting the aired phosphatized plate into an oven at 180 ℃ for drying for 10 min to obtain the epoxy electrophoretic paint coating with excellent corrosion resistance.

Compared with the prior art, the invention has the beneficial effects that:

1. the basic formula of the epoxy coating is modified, so that the corrosion resistance of an electrophoretic paint film under the normal film thickness is obviously improved, and the epoxy coating is characterized by good cooperativity of emulsion and filler, good film forming property, high emulsion stability and excellent salt spray resistance;

2. the epoxy primer for vehicles provided by the invention has better performance, meets the vehicle use requirements on the market, and has longer service life.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art without creative efforts based on the technical solutions of the present invention belong to the protection scope of the present invention.

The first embodiment is as follows:

an epoxy primer with excellent corrosion resistance for a vehicle comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises 50% of ionized water, 5.5:1 of epoxy resin and pigment slurry, 10% of sulfamic acid solution and 0.12% of graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.12), the graphene dispersion slurry comprises 0.3% of graphene, oligomer polyol, KH550 coupling agent and 3% of ethylene glycol butyl ether, the graphene has 6 layers of a lamellar structure, the concentration range of the oligomer polyol is 30% w/v by mass, the polyol is a compound material, a pH meter is used for adjusting the pH of the epoxy electrophoretic paint solution to 5.8, the pH value is adjusted by 10% amino sulfonic acid solution, graphene is dispersed into slurry, the dropping speed is controlled to be 8 drops per minute, the slurry is dropped into electrophoretic paint in the treatment process, and a 1000-mesh nylon filter screen is used for filtering agglomerated particles without the graphene slurry.

Example two:

an epoxy primer with excellent corrosion resistance for a vehicle comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises 45% of ionized water, epoxy resin and pigment slurry (the ratio is 4: 1), 10% of sulfamic acid solution and graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.08), the graphene dispersion slurry comprises graphene, oligomer polyol, 0.1% of KH550 coupling agent and 5% of ethylene glycol butyl ether, the graphene has 3 layers with a lamellar structure, the concentration range of the oligomer polyol is 15% w/v by mass volume, the polyol is a compound material, a pH meter is used for adjusting the pH value of the epoxy electrophoretic paint solution to 5.5, the pH value is adjusted by 10% amino sulfonic acid solution, graphene is dispersed into slurry, the dropping speed is controlled to be 3 drops per minute, the slurry is dropped into electrophoretic paint in the treatment process, and a 1000-mesh nylon filter screen is used for filtering agglomerated particles without the graphene slurry.

Example three:

an epoxy primer with excellent corrosion resistance for a vehicle comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises 55% of ionized water, 7:1 of epoxy resin and pigment slurry, 10% of sulfamic acid solution and 0.18% of graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.18), the graphene dispersion slurry comprises 0.5% of graphene, oligomer polyol, KH550 coupling agent and 1% of ethylene glycol butyl ether, the graphene has 9 layers of a lamellar structure, the concentration range of the oligomer polyol is 50% w/v by mass, the polyol is a compound material, a pH meter is used for adjusting the pH of the epoxy electrophoretic paint solution to 5.9, the pH value is adjusted by 10% amino sulfonic acid solution, graphene is dispersed into slurry, the dropping speed is controlled to be 9 drops per minute, the slurry is dropped into electrophoretic paint in the process, and a 1000-mesh nylon filter screen is used for filtering agglomerated particles without the graphene slurry.

Example four:

an epoxy primer with excellent corrosion resistance for a vehicle comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises 50% of ionized water, 5:1 of epoxy resin and pigment slurry, 10% of sulfamic acid solution and 0.08% of graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.08), the graphene dispersion slurry comprises 3 layers of a lamellar structure, 0.1% of KH550 coupling agent and 5% of ethylene glycol butyl ether, the concentration range of the oligomer polyol is 18% w/v by mass volume, the polyol is a compound material, a pH meter is used for adjusting the pH value of the epoxy electrophoretic paint liquid to 6, the pH value is adjusted by 12% amino sulfonic acid solution, graphene is dispersed into slurry, the dropping speed is controlled to be 3 drops per minute, the slurry is dropped into electrophoretic paint in the treatment process, and a 1000-mesh nylon filter screen is used for filtering agglomerated particles without the graphene slurry.

Example five:

an epoxy primer with excellent corrosion resistance for a vehicle comprises an epoxy electrophoretic paint coating, wherein the epoxy electrophoretic paint coating comprises 52% of ionized water, epoxy resin and pigment slurry (the ratio is 6: 1), 12% of sulfamic acid solution and graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.18), the graphene dispersion slurry comprises graphene, oligomer polyol, 0.5% of KH550 coupling agent and 1% of ethylene glycol butyl ether, the graphene has a 7-layer lamellar structure, the concentration range of the oligomer polyol is 45% w/v by mass, the polyol is a compound material, a pH meter is used for adjusting the pH of the epoxy electrophoretic paint solution to 5.7, the pH value is adjusted by 8% amino sulfonic acid solution, graphene is dispersed into slurry, the dropping speed is controlled to be 7 drops per minute, the slurry is dropped into electrophoretic paint in the treatment process, and a 1000-mesh nylon filter screen is used for filtering agglomerated particles without the graphene slurry.

The best scheme is the scheme of the first embodiment, and the product is characterized by good synergy, good film forming property and high emulsion stability of emulsion and filler, and excellent salt spray resistance.

The film thickness of the coating obtained by the process of the invention is compared with that of the coating obtained by the traditional process

TABLE 3.1 film thickness test

Test point 1

Test point 2

Test point 3

Test point 4

Test point 5

Average film thickness/. mu.m

0% graphene content template (comparative example)

17.1μm

17.0μm

16.8μm

18.4μm

17.8μm

17.4μm

0.01% graphene content template (example 1)

17.1μm

17.8μm

17.0μm

17.1μm

17.2μm

0.1% graphene content template (example 2)

16.4μm

17.1μm

17.6μm

17.7μm

17.2 μm

The salt spray test shows that the paint film of the invention has better corrosion resistance, and compared with various examples for many times, the electrophoresis paint containing 0.01 percent of graphene is subjected to 1000-hour salt spray till the electrophoresis paint containing 0.1 percent of graphene is subjected to 1000-hour salt spray, and in addition, the addition of the graphene can increase the roughness of the electrophoresis paint film, but does not influence the corrosion resistance and the later finish coating.

TABLE 3.2 roughness measurement

Test point 1

Test point 2

Test point 3

Test point 4

Test point 5

Average roughness/mum

0% graphene content template (comparative example)1）

0.20 μm

0.21 μm

0.22 μm

0.01% graphene content template (example 1)

0.25 μm

0.40 μm

0.30 μm

0.37 μm

0.34 μm

0.33 μm

0.1% graphene content template (example 2)

0.41 μm

0.44 μm

0.34 μm

0.44 μm

0.37 μm

0.40 μm

The adhesive force is tested, the adhesive force comparison table is tested by comparing with the Baige method, the conclusion that the adhesive force of the electrophoretic paint film is not affected by adding the graphene is obtained,

in the measurement of the film thickness, a film thickness meter is used for measuring the film thickness, one plate with better paint film quality is selected from the electrophoretic plates, the film thickness of each point is measured by adopting a five-point measurement method, and after the measurement is finished, the data is averaged, recorded and analyzed.

And (3) roughness testing, namely measuring the roughness by using a roughness meter, selecting a plate with better paint film quality from the electrophoresis plate, placing the plate on a horizontal desktop, if the plate is not horizontal, possibly causing inaccurate result, measuring by adopting a five-point measurement method, horizontally placing the roughness meter on a sample plate, testing the roughness, after the test is finished, averaging, recording and analyzing data, and researching the photoresponsiveness of the hydrogel.

And (3) testing adhesive force, namely placing the sample on a horizontal table top, marking equidistant scratches on the film by using a knife, testing the adhesive force by contrasting with a one-hundred-grid method, contrasting with a table 2.5, and observing and determining the adhesive force.

TABLE 2.5 Baige methodTest adhesion contrast table

ISO class	ASTM grade	Test results
			0	5B	The cut edges were completely smooth without any flaking of the grid edges.
1	4B	With small flaking at the intersection of the cuts, actual breakage within the scribed area is no more than 5%.
			2	3B	The edges and/or intersections of the cuts are peeled off to an area greater than 5% but less than 15%.
3	2B	Partial or full flakes along the edges of the cuts, or partial cells, are peeled off in whole pieces over an area of more than 15% but less than 30%.
			4	1B	Large flakes and/or some of the squares partially or completely flake off along the edges of the cuts, with an area of flaking exceeding 35% but less than 65%.
5	0B	Above the upper level is greater than 65%.

And (3) detecting the corrosion resistance, wherein the salt spray test is a test for measuring the corrosion resistance of the metal material by simulating a natural salt spray environment condition by using artificial salt spray equipment. The salt spray test mainly comprises an exposure test in a natural environment and an artificially accelerated salt spray test, and the artificially accelerated salt spray test is more used at present. The experiment was carried out using a neutral salt spray experiment with 5% NaCl solution. The method comprises the following steps: the method is carried out according to the GB/T1771, and two crossed lines are marked before the sample is put into a test and are marked to penetrate to the substrate. The non-scribed area refers to the area from 2mm outside the scribed part of the sample plate to within 5mm of the perimeter of the sample plate. After the test is finished, the phenomena of foaming at the marked part of the sample plate, the corrosion and spread degree of the substrate and the damage of the coating film at the unmarked area are checked.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The epoxy primer with excellent corrosion resistance for the vehicle comprises an epoxy electrophoretic paint coating and is characterized in that: the epoxy electrophoretic paint coating comprises ionized water (45% -55%), epoxy resin and pigment slurry (the proportion ranges from 4:1 to 7: 1), 10% of sulfamic acid solution and graphene dispersion slurry (the ratio of the epoxy resin to the main resin is 0.05-0.2), wherein the graphene dispersion slurry comprises graphene, oligomer polyol, KH550 coupling agent (0.1-0.5%) and ethylene glycol butyl ether (1% -5%).

2. The epoxy primer for vehicle with excellent corrosion resistance according to claim 1, wherein: the graphene has 2-10 layers in a lamellar structure.

3. The epoxy primer for vehicle with excellent corrosion resistance according to claim 1, wherein: the concentration range of the oligomer polyol is 10-50% w/v by mass volume, and the polyol is a compound material.

4. The epoxy primer for vehicle with excellent corrosion resistance according to claim 1, wherein: the pH of the epoxy resin electrophoretic paint liquid is adjusted to about 5.5-6.0 by a pH meter, and the pH is adjusted by 10 percent of amino sulfonic acid solution.

5. The epoxy primer for vehicle with excellent corrosion resistance according to claim 1, wherein: dispersing the graphene slurry, controlling the dropping speed to be 5-10 drops per minute, dropping the graphene slurry into the electrophoretic paint in the treatment process, and filtering the agglomerated particles without the graphene slurry by using a 1000-mesh nylon filter screen.

6. The preparation method of the epoxy primer for vehicles with excellent corrosion resistance according to claim 1, characterized by comprising the following steps: