PVDF (Polyvinylidene Fluoride) varnish and preparation process thereof

Abstract

The invention relates to the technical field of coatings, and discloses PVDF varnish and a manufacturing process thereof.The PVDF varnish is prepared from, by weight, 40-60 parts of PVDF powder, 40-60 parts of acrylic resin, 60-80 parts of isophorone, 0.5-1.5 parts of amino resin, 3-7 parts of a flatting agent, 2-4 parts of a defoaming agent, 1-3 parts of a thickening agent and 1-3 parts of an ultraviolet light absorber, the flatting agent is an organic silicon flatting agent, the defoaming agent is a mineral oil defoaming agent, and the thickening agent is an organic silicon flatting agent. The thickening agent is a cellulose thickening agent, the ultraviolet light absorber is a benzotriazole ultraviolet light absorber, and the preparation method comprises the following steps: S1, preparation before preparation, S2, raw material addition and dispersion, S3, comprehensive dispersion, S4, filtration and detection, and S5, cleaning and after-treatment work. The PVDF powder, the acrylic resin, the isophorone and the amino resin are combined, and the leveling agent, the defoaming agent, the thickening agent and the ultraviolet light absorber are added, so that the leveling property of the varnish is improved, bubbles are reduced, the appearance quality of the varnish is improved, and the service life of the varnish is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a PVDF varnish and a preparation process thereof. Background Art

[0002] PVDF varnish is often used for surface protection of metal curtain walls and roofs to provide excellent weather resistance and corrosion resistance and extend the service life of buildings. In the automotive industry, PVDF varnish can provide the car body with beautiful appearance and good protection. In the field of electronics and electrical, PVDF varnish can be used for protective coating of circuit boards to ensure the stable operation of electronic equipment.

[0003] The existing PVDF varnish has poor advection during the construction process, which makes the PVDF varnish unevenly dispersed, affects the stability of its performance, leads to poor adhesion of the varnish, is prone to peeling, and reduces the service life of the PVDF varnish. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a PVDF varnish and a production process thereof, which solves the problem of uneven dispersion of the PVDF varnish causing shedding and reduced service life.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a PVDF varnish, comprising the following raw materials in parts by weight: 40 to 60 parts of PVDF powder, 40 to 60 parts of acrylic resin, 60 to 80 parts of isophorone, 0.5 to 1.5 parts of amino resin, 3 to 7 parts of leveling agent, 2 to 4 parts of defoaming agent, 1 to 3 parts of thickener and 1 to 3 parts of ultraviolet absorber.

[0006] Preferably, the leveling agent is an organic silicon leveling agent, the defoaming agent is a mineral oil defoaming agent, the thickener is a cellulose thickener, and the ultraviolet absorber is a benzotriazole ultraviolet absorber.

[0007] A PVDF varnish production process, the PVDF varnish production process comprising the following steps:

[0008] S1. Preparation before production. Before each production, clean the inside of the ton cylinder again with cleaning solvent. After cleaning, place the cylinder directly under the disperser;

[0009] S2, raw material addition and preliminary dispersion, first pour the cleaning solvent into the cylinder, turn on the disperser to slowly disperse, then add PVDF powder, slowly disperse for more than 30 minutes until the powder is completely dissolved in the liquid, then disperse at high speed for 30 to 60 minutes, and check the dissolution;

[0010] S3, comprehensive dispersion, after the PVDF powder is completely dissolved, add acrylic resin and disperse at high speed for 60 minutes, then add amino resin, leveling agent, defoamer, dispersant, thickener and ultraviolet absorber in sequence, and disperse at high speed for 30 minutes after adding each raw material.

[0011] S4, Filtration and testing. After the production is completed, use high-pressure filtration equipment and 400-500 mesh filter bags to filter a small amount of samples for testing first, and then filter the PVDF varnish in the tank evenly one by one into a clean toilet and seal it tightly.

[0012] S5. Clean up the aftermath and use cleaning solvent to clean the site and ton tanks, high-speed dispersers, and high-pressure filtration equipment.

[0013] Preferably, in S4, sampling is performed to detect the viscosity, scraper thickness, T-bend and wiping index of the PVDF varnish.

[0014] Preferably, in S2, the stirring speed is 300 to 500 rpm during slow dispersion, and the stirring speed is 1000 to 1500 rpm during high-speed dispersion.

[0015] Preferably, in S5, the cleaning solvent is isophorone.

[0016] Preferably, during the PVDF varnish production process, the temperature of the entire production environment is between 20 and 30° C., and the humidity is between 40% and 60%.

[0017] Preferably, the toilet needs to be cleaned and dried before use.

[0018] Preferably, in S3, the raw materials should be added in the order of solid first and liquid second, and the disperser should be kept running during the adding process.

[0019] Preferably, in S4, the samples for sampling and testing are stored in a light-proof condition and the storage time does not exceed 2 hours.

[0020] The present invention provides a PVDF varnish and a production process thereof, which has the following beneficial effects:

[0021] 1. The present invention combines PVDF powder, acrylic resin, isophorone and amino resin, and adds a leveling agent, a defoaming agent, a thickener and an ultraviolet absorber thereto to increase the leveling property of the varnish, reduce bubble generation, adjust the viscosity, and enhance its anti-ultraviolet ability, thereby improving the appearance quality and service life of the varnish, and can give the varnish good film-forming property, weather resistance, and chemical corrosion resistance.

[0022] 2. The present invention limits the temperature and humidity of the production environment so that the temperature and humidity of the production environment remain stable, and requires the toilet bowl to be cleaned and dried before use to ensure that the varnish is not contaminated. At the same time, it is conducive to long-term storage. Isophorone is used to clean the equipment to avoid adverse effects of different solvent residues on the next production, keep the equipment in good condition, help reduce the interference of environmental factors on the production process and varnish performance, and improve product consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of a PVDF varnish production process. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example:

[0026] Please see attached Figure 1 The embodiment of the present invention provides a PVDF varnish, comprising the following raw materials in parts by weight: 40-60 parts of PVDF powder, 40-60 parts of acrylic resin, 60-80 parts of isophorone, 0.5-1.5 parts of amino resin, 3-7 parts of leveling agent, 2-4 parts of defoaming agent, 1-3 parts of thickener and 1-3 parts of ultraviolet absorber.

[0027] The leveling agent is an organic silicon leveling agent, the defoaming agent is a mineral oil defoaming agent, the thickener is a cellulose thickener, and the ultraviolet absorber is a benzotriazole ultraviolet absorber.

[0028] A PVDF varnish production process, the PVDF varnish production process comprising the following steps:

[0029] S1. Preparation before production. Before each production, clean the inside of the ton cylinder again with cleaning solvent. After cleaning, place the cylinder directly under the disperser;

[0030] S2, raw material addition and preliminary dispersion, first pour the cleaning solvent into the cylinder, turn on the disperser to slowly disperse, then add PVDF powder, slowly disperse for more than 30 minutes until the powder is completely dissolved in the liquid, then disperse at high speed for 30 to 60 minutes, and check the dissolution;

[0031] S3, comprehensive dispersion, after the PVDF powder is completely dissolved, add acrylic resin and disperse at high speed for 60 minutes, then add amino resin, leveling agent, defoamer, dispersant, thickener and ultraviolet absorber in sequence, and disperse at high speed for 30 minutes after adding each raw material.

[0032] S4. Filtration and testing. After production is completed, use high-pressure filtration equipment and 400-500 mesh filter bags to filter a small amount of samples for testing. Then, filter the PVDF varnish in the tank one by one evenly into a clean toilet, seal it tightly, weigh it and label it. The label content includes the product name, weight and production date.

[0033] S5. Clean up the aftermath and use cleaning solvent to clean the site and ton tanks, high-speed dispersers, and high-pressure filtration equipment.

[0034] In S4, samples are taken to test the viscosity, scraper thickness, T-bend and wiping index of the PVDF varnish.

[0035] Viscosity detection:

[0036] Prepare the rotational viscometer, take an appropriate amount of varnish sample from the filtered sampling and put it into the measuring container of the viscometer;

[0037] Then set the measuring speed and temperature, start the viscometer for measurement, record the measured viscosity value, and compare it with the viscosity range required by the standard.

[0038] Scraper thickness detection:

[0039] Use a scraper gauge to evenly apply the sampled varnish on the grooves of the scraper gauge;

[0040] Use a scraper to scrape across the grooves so that the varnish fills the grooves;

[0041] Observe the scale displayed on the scraper fineness meter, determine the value of the scraper coarseness, and compare it with the standard requirements.

[0042] T-bend detection:

[0043] Prepare primed metal test pieces;

[0044] The sampled PVDF varnish is evenly coated on the test piece and dried according to the prescribed drying conditions;

[0045] Use T-bend test equipment to bend the dried coating;

[0046] Observe whether the coating cracks or peels off at the bend, and evaluate whether the T-bend performance meets the requirements.

[0047] Wipe test:

[0048] Prepare a test panel coated with PVDF varnish and dried;

[0049] Use a paper towel dipped in ethanol to wipe the coating surface back and forth;

[0050] Observe whether the coating surface has faded or exposed bottom after wiping to determine whether the coating's wipe resistance performance meets the standard.

[0051] In S2, the stirring speed is 300 to 500 rpm during slow dispersion, and the stirring speed is 1000 to 1500 rpm during high-speed dispersion.

[0052] In S5, the cleaning solvent is isophorone.

[0053] During the PVDF varnish production process, the entire production environment temperature is between 20 and 30°C and the humidity is between 40% and 60%.

[0054] The toilet needs to be cleaned and dried before use.

[0055] In S3, the raw materials should be added in the order of solid first and liquid second, and the disperser should be kept running during the addition process.

[0056] In S4, the samples for sampling and testing are stored in a light-proof condition and the storage time does not exceed 2 hours.

[0057] The following is an introduction in conjunction with specific embodiments:

[0058] Embodiment 1:

[0059] A PVDF varnish comprises the following raw materials in parts by weight: 40 parts of PVDF powder, 40 parts of acrylic resin, 60 parts of isophorone, 0.5 parts of amino resin, 3 parts of leveling agent, 2 parts of defoaming agent, 1 part of thickener and 1 part of ultraviolet absorber.

[0060] The PVDF varnish production process includes the following steps:

[0061] Preparation before production: Before each production, clean the inside of the ton cylinder again with isophorone, and after cleaning, place the cylinder directly under the disperser;

[0062] Raw material addition and dispersion: first pour isophorone into the cylinder, start the disperser to slowly disperse at a speed of 300 rpm, then add PVDF powder, slowly disperse for more than 30 minutes until the powder is completely dissolved in the liquid, then disperse at a high speed of 1000 rpm for 30 minutes, and check the dissolution;

[0063] Comprehensive dispersion: after the PVDF powder is completely dissolved, add acrylic resin and disperse at high speed for 60 minutes, then add amino resin, leveling agent, defoamer, dispersant, thickener and ultraviolet absorber in sequence, and disperse at high speed for 30 minutes at 1000 rpm after adding each raw material;

[0064] Filtration and testing: After the production is completed, use high-pressure filtration equipment and a 400-mesh filter bag to first filter a small amount of samples to test the viscosity, scraper coarseness, T-bend and wiping indicators of the PVDF varnish, and then filter the PVDF varnish in the cylinder one by one evenly into a clean, cleaned and dried toilet, and seal it tightly;

[0065] Cleaning and post-processing work: Use isophorone as the cleaning solvent to clean the site and ton tanks, high-speed dispersers, and high-pressure filtration equipment; during the entire production process, the ambient temperature is controlled at 20°C and the humidity is controlled at 40%.

[0066] Embodiment 2:

[0067] A PVDF varnish comprises the following raw materials in parts by weight: 50 parts of PVDF powder, 50 parts of acrylic resin, 70 parts of isophorone, 1 part of amino resin, 5 parts of leveling agent, 3 parts of defoaming agent, 2 parts of thickener and 2 parts of ultraviolet absorber.

[0068] The PVDF varnish production process includes the following steps:

[0069] Preparation before production: Before each production, clean the inside of the ton cylinder again with isophorone, and after cleaning, place the cylinder directly under the disperser;

[0070] Addition and dispersion of raw materials: first pour isophorone into the cylinder, start the disperser to slowly disperse at a speed of 400 rpm, then add PVDF powder, slowly disperse for more than 30 minutes until the powder is completely dissolved in the liquid, then disperse at a high speed of 1200 rpm for 45 minutes, and check the dissolution;

[0071] Comprehensive dispersion: after the PVDF powder is completely dissolved, add acrylic resin and disperse at high speed for 60 minutes, then add amino resin, leveling agent, defoamer, dispersant, thickener and ultraviolet absorber in sequence, and disperse at high speed for 30 minutes at 1200 rpm after adding each raw material;

[0072] Filtration and testing: After the production is completed, use high-pressure filtration equipment and a 450-mesh filter bag to first filter a small amount of samples to test the viscosity, scraper coarseness, T-bend and wiping indicators of the PVDF varnish, and then filter the PVDF varnish in the cylinder one by one evenly into a clean, cleaned and dried toilet, and seal it tightly;

[0073] Cleaning and post-processing work: Use isophorone as the cleaning solvent to clean the site and ton tanks, high-speed dispersers, and high-pressure filtration equipment; during the entire production process, the ambient temperature is controlled at 25°C and the humidity is controlled at 50%.

[0074] Embodiment three:

[0075] A PVDF varnish comprises the following raw materials in parts by weight: 60 parts of PVDF powder, 60 parts of acrylic resin, 80 parts of isophorone, 1.5 parts of amino resin, 7 parts of leveling agent, 4 parts of defoaming agent, 3 parts of thickener and 3 parts of ultraviolet absorber.

[0076] The PVDF varnish production process includes the following steps:

[0077] Preparation before production: Before each production, clean the inside of the ton cylinder again with isophorone, and after cleaning, place the cylinder directly under the disperser;

[0078] Raw material addition and dispersion: first pour isophorone into the cylinder, start the disperser to slowly disperse at a speed of 500 rpm, then add PVDF powder, slowly disperse for more than 30 minutes until the powder is completely dissolved in the liquid, then disperse at a high speed of 1500 rpm for 60 minutes, and check the dissolution;

[0079] Comprehensive dispersion: after the PVDF powder is completely dissolved, add acrylic resin and disperse at high speed for 60 minutes, then add amino resin, leveling agent, defoamer, dispersant, thickener and ultraviolet absorber in sequence, and disperse at high speed for 30 minutes at 1500 rpm after adding each raw material;

[0080] Filtration and testing: After the production is completed, use high-pressure filtration equipment and a 500-mesh filter bag to first filter a small amount of samples to test the viscosity, scraper coarseness, T-bend and wiping indicators of the PVDF varnish, and then filter the PVDF varnish in the cylinder one by one evenly into a clean, cleaned and dried toilet, and seal it tightly;

[0081] Cleaning and post-processing work: Use isophorone as the cleaning solvent to clean the site and ton tanks, high-speed dispersers, and high-pressure filtration equipment; during the entire production process, the ambient temperature is controlled at 30°C and the humidity is controlled at 60%.

[0082] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A PVDF varnish, characterized in that: The invention comprises the following raw materials in parts by weight: 40-60 parts of PVDF powder, 40-60 parts of acrylic resin, 60-80 parts of isophorone, 0.5-1.5 parts of amino resin, 3-7 parts of leveling agent, 2-4 parts of defoaming agent, 1-3 parts of thickener and 1-3 parts of ultraviolet absorber.

2. A PVDF varnish according to claim 1, characterized in that: The leveling agent is an organic silicon leveling agent, the defoaming agent is a mineral oil defoaming agent, the thickener is a cellulose thickener, and the ultraviolet absorber is a benzotriazole ultraviolet absorber.

3. A PVDF varnish production process, characterized in that: A PVDF varnish applied to any one of claims 1-2, wherein the PVDF varnish production process comprises the following steps: S1. Preparation before production. Before each production, clean the inside of the ton cylinder again with cleaning solvent. After cleaning, place the cylinder directly under the disperser; S2, raw material addition and preliminary dispersion, first pour the cleaning solvent into the cylinder, turn on the disperser to slowly disperse, then add PVDF powder, slowly disperse for more than 30 minutes until the powder is completely dissolved in the liquid, then disperse at high speed for 30 to 60 minutes, and check the dissolution; S3, comprehensive dispersion, after the PVDF powder is completely dissolved, add acrylic resin and disperse at high speed for 60 minutes, then add amino resin, leveling agent, defoamer, dispersant, thickener and ultraviolet absorber in sequence, and disperse at high speed for 30 minutes after adding each raw material. S4, Filtration and testing. After the production is completed, use high-pressure filtration equipment and 400-500 mesh filter bags to filter a small amount of samples for testing first, and then filter the PVDF varnish in the tank evenly one by one into a clean toilet and seal it tightly. S5. Clean up the aftermath and use cleaning solvent to clean the site and ton tanks, high-speed dispersers, and high-pressure filtration equipment.

4. A PVDF varnish production process according to claim 3, characterized in that: In S4, sampling is performed to detect the viscosity, scraper thickness, T-bend and wiping index of the PVDF varnish.

5. A PVDF varnish and a production process thereof according to claim 3, characterized in that: In the S2, the stirring speed is 300 to 500 rpm during slow dispersion, and the stirring speed is 1000 to 1500 rpm during high-speed dispersion.

6. A PVDF varnish production process according to claim 3, characterized in that: In the step S5, the cleaning solvent is isophorone.

7. A PVDF varnish production process according to claim 3, characterized in that: During the PVDF varnish production process, the temperature of the entire production environment is between 20 and 30° C., and the humidity is between 40% and 60%.

8. A PVDF varnish production process according to claim 3, characterized in that: The toilet needs to be cleaned and dried before use.

9. A PVDF varnish production process according to claim 3, characterized in that: In S3, the raw materials should be added in the order of solid first and liquid second, and the disperser should be kept running during the adding process.

10. A PVDF varnish production process according to claim 3, characterized in that: In S4, the samples for sampling and testing are stored in a light-proof condition and the storage time does not exceed 2 hours.

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