A water-based roll and spray coating material, a preparation method and application thereof

Abstract

The application discloses a water-based roll-spray paint as well as a preparation method and application thereof. The preparation raw materials of the water-based roll-spray paint include the following components in parts by weight: 30-45 parts of a first water-based epoxy resin, 10-15 parts of a second water-based epoxy resin, 1-2 parts of a dispersing agent, 1-20 parts of water, 5-10 parts of a filler, 0.1-0.5 parts of a pH regulator and 3-5 parts of an amino resin. The water-based system is adopted, environmental protection requirements are met, excellent chemical resistance is achieved, no abnormality is found after oleic acid immersion for 72 hours under high temperature and high humidity, the required film thickness is low, the water-based roll-spray paint is suitable for application on small-size NdFeB magnetic steel materials, the minimum film thickness of 5 microns can meet the performance test in a table, good construction performance is achieved, no adhesion is found between single highest spraying materials of more than 40 microns, compared with multiple roll-spraying to reach the target film thickness, production time is greatly saved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coatings, and particularly relates to a water-based roll-spray coating material as well as a preparation method and application thereof. BACKGROUND

[0002] At present, small-size Nd-Fe-B magnetic steel parts are applied more and more widely in the market, but because they are mostly profiled parts and have very small sizes, the conventional spraying methods such as automatic line spraying cannot achieve good coating. Therefore, people have developed various spraying methods for such materials, and two commonly used methods are as follows: one is to use conventional epoxy coating, spray one side with a reciprocating machine, and then spray the other side after curing, which is very low in efficiency; the other is a roll-spray process, in which the material and a plating aid are put into a roll-spray machine together, the material is gradually coated with a film through the contact with the ball-shaped plating aid, which is high in efficiency, low in resource waste, and uniform in film thickness, and therefore has great development space. Epoxy coating is commonly used in the roll-spray process, but conventional epoxy coating has limited chemical resistance (corrosion resistance) and is mostly solvent-based coating, which is highly polluting. Moreover, because the parts are prone to sticking in the roll-spray process of conventional epoxy coating, the parts can only be sprayed for a while, taken out for curing, and then put into the roll-spray machine for spraying again, and the above process is repeated for 3-6 times to achieve the required film thickness (the film thickness is high to meet the chemical resistance requirement), which cannot achieve the film thickness requirement in a single spraying, is low in spraying efficiency, and is time- and labor-consuming.

[0003] Therefore, it is a main technical problem to be solved at present to develop a roll-spray coating material specially used for small-size Nd-Fe-B magnets, which has great economic value. SUMMARY

[0004] The present application aims to overcome the deficiencies and defects mentioned in the background and provide a water-based roll-spray coating material as well as a preparation method and application thereof to improve the workability and chemical resistance.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows:

[0006] A water-based roll-spray coating material, which is prepared from the following components by weight: 30-45 parts of a first water-based epoxy resin, 10-15 parts of a second water-based epoxy resin, 1-2 parts of a dispersing agent, 1-20 parts of water, 5-10 parts of a filler, 0.1-0.5 parts of a pH adjuster, and 3-5 parts of an amino resin.

[0007] The epoxy equivalent weight of the first water-based epoxy resin is 900-1060 g / mol.

[0008] The second water-based epoxy resin is a reaction-type emulsifier modified bisphenol A type epoxy resin with an epoxy equivalent weight of 520-600 g / Eq.

[0009] As a further improvement, the preparation raw materials further include 10-20 parts of color paste, 0.2-0.5 parts of defoaming agent, 1-2 parts of wetting agent, 5-10 parts of film-forming aid, and 3-5 parts of adhesion promoter.

[0010] As a further improvement, the viscosity of the first water-based epoxy resin is 200-6000 cP, and the solid content is 52±2%.

[0011] As a further improvement, the first water-based epoxy resin uses JT-WBE522 of Polyco Technology.

[0012] As a further improvement, the second water-based epoxy resin uses E-pos1011W55 of QR-Polymers.

[0013] As a further improvement, the filler is talc powder.

[0014] As a further improvement, the pH regulator is an amine neutralizer.

[0015] The application provides a preparation method of the water-based roll and spray paint.

[0016] The defoaming agent, wetting agent, and film-forming aid are added to the first water-based epoxy resin and the second water-based epoxy resin under stirring, and mixed uniformly;

[0017] The dispersant and the filler are added under stirring, and mixed uniformly;

[0018] The color paste, amino resin, and adhesion promoter are added under stirring, and mixed uniformly;

[0019] The previously mixed deionized water and pH regulator are added, dispersed uniformly, filtered, and the water-based roll and spray paint is obtained.

[0020] The application provides an application of the water-based roll and spray paint, which is coated on a substrate by a roll and spray method, and then baked to obtain a dry film.

[0021] As a further improvement, a single roll and spray is performed to obtain a film thickness of 5-15 μm.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] (1) The water-based roll and spray paint of the present application can be applied to small-sized Nd-Fe-B magnetic steel materials, has good workability, stable oil output during spraying, and no adhesion between single highest sprayed 40pm or more substrates, greatly saving production time compared to multiple roll and spray to achieve the target film thickness.

[0024] (2) The paint of the present application requires a low film thickness, with a minimum of 5pm to meet the performance test requirements, and a single roll coating to achieve a target film thickness of 5-15pm.

[0025] (3) The paint of the present application has excellent chemical resistance, and only 5pm thick paint film can pass the 72h test under high temperature and high humidity (temperature 65℃, humidity 90%) conditions.

[0026] (4) The paint of the present application uses a water-based system, with a theoretical calculation of VOC < 300g / L, less organic solvent volatilization, and meets environmental protection requirements. DETAILED DESCRIPTION

[0027] In order to facilitate understanding of the present application, the following will combine the preferred embodiments to describe the present application more fully and in detail, but the protection scope of the present application is not limited to the following specific embodiments.

[0028] Unless otherwise defined, all professional terms used herein have the same meaning as generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or prepared by existing methods.

[0030] In some embodiments, the water-based roll and spray paint of the present application comprises the following components by weight: 30-45 parts of a first water-based epoxy resin, 10-15 parts of a second water-based epoxy resin, 10-20 parts of a color paste, 0.2-0.5 parts of a defoaming agent, 1-2 parts of a wetting agent, 1-2 parts of a dispersing agent, 1-20 parts of water, 5-10 parts of a filler, 5-10 parts of a film-forming aid, 0.1-0.5 parts of a pH adjuster, 3-5 parts of an amino resin, and 3-5 parts of an adhesion promoter.

[0031] The first water-based epoxy resin has an epoxy equivalent weight of 900-1060g / mol, a viscosity of preferably 200-6000cP, and a solid content of preferably 52±2%. Specifically, JT-WBE522 from Polyco Technology can be used. It has excellent shear stability and abrasion resistance, fast drying, and excellent initial water resistance.

[0032] The second aqueous epoxy resin is a bisphenol A type epoxy resin modified by a reactive emulsifier, with an epoxy equivalent weight (solid state) of 520-600 g / Eq; the solid content is preferably 51-55%. Specifically, E-pos1011W55 produced by QR-Polymers Company can be used. It has good corrosion resistance on various substrates.

[0033] In the prior art, it is difficult to achieve good oleic acid resistance. The present application uses two specific aqueous epoxy resins to significantly improve the resistance to chemicals, while also considering adhesion and workability. The first or second aqueous epoxy resin alone does not have good resistance to chemicals, and fails the oleic acid and salt spray tests. The second aqueous epoxy resin alone also has adhesion and workability problems.

[0034] In some embodiments, the color paste used in the present application is black paste with a solid content of 35wt%, which is prepared by grinding high-pigment carbon black and has good compatibility with the system. The color paint prepared has no color floating after 3 months, good hiding power, and can completely cover the substrate at a film thickness of 5μm.

[0035] In some embodiments, the defoaming agent used in the present application is one or more of polyether siloxane copolymer, polydimethylsiloxane, specifically one or more of tegos 902W of Degussa Company and BYK024 of BYK-Chemie.

[0036] In some embodiments, the wetting agent used in the present application is an organosiloxane surfactant based on Gemini technology, which has excellent oil stain resistance and anti-cratering ability, specifically Greesol GS195 of Yueyang Kaimen.

[0037] In some embodiments, the dispersant used in the present application is one or more of high molecular weight block copolymer solution, copolymer containing pigment affinity group, and organic modified polyacrylate solution containing pigment affinity group. The dispersant is used to disperse the flatting powder, so that the prepared coating has strong uniformity and is fine and non-flocculent. Specifically, one or more of BYK2012 and BYK2013 of BYK;

[0038] In some embodiments, the filler used in the present application is talc powder, specifically 3000 mesh ultra-fine talc powder of Guangdong Shengpeng Powder Material Company.

[0039] In some embodiments, the film-forming aid used in the present application is DPNB.

[0040] In some embodiments, the pH adjuster used in the present application is an amine neutralizer, which adjusts the pH of the coating to a weakly alkaline range, which is beneficial for the storage of water-based coatings, improves the activation and prevents sedimentation, etc. Specifically, DMEA.

[0041] In some embodiments, the amino resin used in the present application is isobutyl alcohol methyl ether high imino melamine crosslinking agent, specifically CYMEL 325 of allnex.

[0042] In some embodiments, the adhesion promoter used in the present application is 3-glycidyl ether propyl trimethoxysilane, which forms a chemical bond between the coating and the substrate surface through active organic epoxy groups and hydrolyzable methoxysilane groups, thereby improving adhesion, specifically GLYMO of evonik. GLYMO.

[0043] In some specific embodiments, the preparation method of the water-based roll and spray coating of the present application comprises:

[0044] The defoaming agent, wetting agent and film-forming aid are added to the first water-based epoxy resin and the second water-based epoxy resin under stirring and mixed uniformly;

[0045] The dispersant and the filler are added under stirring and mixed uniformly;

[0046] The color paste, amino resin and adhesion promoter are added under stirring and mixed uniformly;

[0047] The pre-mixed deionized water and pH adjuster are added, dispersed uniformly, filtered and the water-based roll and spray coating is obtained.

[0048] In some specific embodiments, the application method of the water-based roll and spray coating of the present application is to coat on the substrate by roll and spray method, the film thickness is 5-15 μm, and the dry film is obtained by baking at 120-180 ℃.

[0049] The product of the present application is a water-based roll and spray coating with excellent chemical resistance, but is not limited to roll and spray, and is also applicable to other methods such as automatic line spraying.

[0050] Examples and comparative examples:

[0051] The preparation raw materials and weight parts of the water-based roll and spray coating of examples 1-4 and comparative examples 1-4 are shown in table 1 and table 2. Among them, the first water-based epoxy resin is JT-WBE522 of poly coating technology, the second water-based epoxy resin is E-pos 1011W55 of QR-Polymers company, the black paste solid content is 35wt%, the defoaming agent is tego902W of degao company, the wetting agent is Greesol GS195 of Yueyang kemen, the dispersant is BYK2012 of BYK, the filler is 3000 mesh superfine talc powder of Guangdong shenpeng powder material company, the film-forming aid is DPNB, the pH adjuster is DMEA, the amino resin is CYMEL325 of allnex, and the adhesion promoter is GLYMO of evonik. GLYMO.

[0052] The preparation method of the water-based roll and spray coating of Examples 1-4 and Comparative Examples 1-4 is as follows:

[0053] S1, the first water-based epoxy resin and the second water-based epoxy resin in the components are added to a dispersion container;

[0054] S2, the defoaming agent, wetting agent and film-forming aid are added under 600-800 rpm, and stirred for 5-8 minutes;

[0055] S3, the rotational speed is increased to 800-1000 rpm, the dispersing agent and the filler are added, and high-speed stirring is performed for 10-20 minutes, and attention is paid to scraping the edge, and cooling is paid attention to during the process;

[0056] S4, the rotational speed is reduced to 600-8000 rpm, the color paste, amino resin and adhesion promoter are added, and stirring is performed for 3-5 minutes;

[0057] S5, deionized water and pH adjuster are further added; the deionized water and the pH adjuster are pre-mixed and statically placed at room temperature for 5 minutes or more before being added; the pH is adjusted by using the pH adjuster, and the viscosity is adjusted by using the deionized water (the temperature is controlled at 5-35°C throughout the process);

[0058] S6, the water-based roll and spray coating is obtained by filtering and packaging with a 250-350 mesh filter.

[0059] Table 1: Components and weight parts of each example

[0060]

[0061]

[0062] Table 2: Components and weight parts of each comparative example

[0063]

[0064]

[0065] Performance test:

[0066] Construction method: the water-based roll and spray coating prepared by the above Examples 1-4 and Comparative Examples 1-4 is added with water to adjust the viscosity to a suitable construction viscosity, and is coated on the substrate by roll and spray method, the single roll coating film thickness is 5-15 μm, and the dry film with the final effect is obtained after 150°C baking for 30 minutes. The performance test items are shown in Table 3:

[0067] Table 3: Performance test results

[0068]

[0069]

[0070] As can be seen, the examples 1 to 4 have excellent resistance to chemicals (oleic acid, salt spray), adhesion and workability. The comparative examples 1 to 2 have no first water-based epoxy resin added, poor resistance to chemicals (oleic acid and salt spray test NG), and poor adhesion and workability. The comparative examples 3 to 4 have no second water-based epoxy resin added, poor resistance to chemicals (oleic acid and salt spray test NG).

[0071] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present application, without departing from the technical scheme of the present application, shall fall within the protection scope of the technical scheme of the present application.

Claims

1. An aqueous roll and spray coating material, characterized in that, The raw materials for preparing the water-based roll and spray paint include the following components in parts by weight: 30-45 parts of a first water-based epoxy resin, 10-15 parts of a second water-based epoxy resin, 1-2 parts of a dispersant, 1-20 parts of water, 5-10 parts of a filler, 0.1-0.5 parts of a pH regulator, and 3-5 parts of an amino resin; The first water-based epoxy resin has an epoxy equivalent weight of 900-1060 g / mol, a viscosity of 200-6000 cP, and a solid content of 52±2%, and the first water-based epoxy resin is JT-WBE522 from Polyco Technology; The second water-based epoxy resin is a bisphenol A type epoxy resin modified by a reactive emulsifier, and has an epoxy equivalent weight of 520-600 g / Eq, and the second water-based epoxy resin is E-pos 1011W55 from QR-Polymers.

2. The water-based roll and spray coating according to claim 1, characterized in that, The raw materials further include 10-20 parts of a color paste, 0.2-0.5 parts of an antifoaming agent, 1-2 parts of a wetting agent, 5-10 parts of a film-forming aid, and 3-5 parts of an adhesion promoter.

3. The water-based roll and spray coating according to claim 1 or 2, characterized in that, The filler is talc.

4. The water-based roll and spray coating of claim 1, wherein, The pH regulator is an amine neutralizer.

5. A method for preparing the aqueous roll and spray coating material according to any one of claims 1 to 4, characterized in that The steps include the following: The antifoaming agent, the wetting agent, and the film-forming aid are added to the first water-based epoxy resin and the second water-based epoxy resin under stirring, and are mixed uniformly; The dispersant and the filler are added under stirring, and are mixed uniformly; The color paste, the amino resin, and the adhesion promoter are added under stirring, and are mixed uniformly; The pre-mixed deionized water and the pH regulator are added, and are dispersed uniformly, filtered, and then the water-based roll and spray paint is obtained.

6. Use of the aqueous roll and spray coating material according to any one of claims 1 to 4, characterized in that The water-based roll and spray paint is coated on a substrate by roll and spray, and then a dry film is obtained by baking.

7. Use according to claim 6, characterized in that, The film thickness is 5-15 μm after a single roll and spray.

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