Aqueous industrial resin-free color paste grinding process and performance evaluation
Coating Industry:
Abstract:
In this paper, 14 pigment pastes were prepared using three new highly efficient and high performance dispersants from SAMASO Chemical Company offering SAMASO, and the pastes were evaluated for phase solubility in four common linker resins. The experimental results show that the aqueous industrial resin-free pigment pastes made with the three SAMASO & CPT dispersants from SAMASO Chemical meet the requirements of aqueous industrial paints with high versatility, excellent salt spray resistance, and excellent water/alcohol/different solvent compatibility, providing a new way for the development of aqueous industrial paint pastes.
1 Preface
As the country pays more and more attention to environmental protection, many chemical companies have been moving towards energy saving, environmental protection and safety in the field of new technology materials, water-based industrial paint development is a typical example. Water-based industrial paints mainly include water-based resin linker, water-based color paste, solvent water, co-solvent and functional additives, among which water-based resin linker is gradually developed into three series of water emulsion, water emulsion and water dilutable according to the actual application needs in industrial production [1], and also includes five types of water-based alkyd resin, water-based epoxy resin, water-based acrylic resin and water-based polyurethane resin. species. However, the traditional color mixing of waterborne industrial paints always suffers from the limitation that the formulation reagents cannot be homogenized, resulting in the fixation of the available additives for each resin. For example, there are almost no reagents that can be used to achieve stable uniformity for all pigments and excellent blendability for all types of connector resins.
2 Preparation and testing of aqueous resin-free pastes
2.1 Preparation materials
Pigments: Phthalocyanine blue, Changzhou North America; Phthalocyanine green, Zhenjiang; P.Y.154 yellow, Changzhou North America; P.Y.74 yellow, Changzhou North America, P.Y.83 yellow, Clariant; P.R.122 red, Hangzhou Lily; P.R.254 red, Hangzhou Lily; P.V.23 violet, Nubiola; R-706 titanium dioxide, DuPont.
Additives: SAMASO DP6210, SAMASO DP6211, SAMASO DP6213, Triethanolamine, TEGO 810.
Resin: DSM resin, Beijing Jinhuili, Tongde Chemical, Shanghai Xinhua Resin, Guangzhou Shiyuan Chemical, and sample evaluation from customers
2.2 Preparation equipment and instruments
Electronic balance: one thousandth, METTLER; blue type high-speed dispersion grinder WJ-0.5, Shanghai Tianchen Modern Environment; 25 μm wire rod, Modern Environment XB-25; oscillating machine: Foshan Shunde Precision Zone Billion Intelligent Machinery Co.
2.3 Preparation method of water-based resin-free color paste
According to the order of the formula in Table 1, the solvent water, dispersant and defoamer were added into the dispersion cylinder first, and the high-speed disperser was turned on to dissolve the dispersant evenly and completely by using the dispersion disk.
Next, add different color powders of measurement units into the dispersion cylinder separately in proportion to the formula; disperse until the color powders are completely dissolved into the liquid, transfer this disperse color paste into an oscillating tin or glass jar and seal it into the oscillating machine; adjust to the oscillating grinding time of 6 h.
After the oscillation time is finished, the samples are taken out and unsealed, the remaining water is added to make up the percentage, and the color paste is filtered with 200-400 mesh to get the stock solution.
Table 1 Formulation of 8 kinds of common organic pigment pastes
Table 2 4 kinds of commonly used carbon black pigment color paste formulations
Table 3 2 kinds of commonly used titanium white pigment color paste formulations
2.4 Water-based resin-free color paste performance test method
1
Color difference test: When the system contains a diluting agent, it is necessary to test the compatibility of the pigment and the diluting agent. Generally, it is done by finger grinding method, i.e., using fingers to draw circles on the paint that has been coated and not yet dried, with the purpose of showing the difference between the color on the surface of the paint and the internal color by drawing circles back [2].
2
The transferability test: In the resin linker, the compatibility between the pigment paste and the base linker is tested. The pigment paste is added to the resin of the joint material and the two are mixed by stirring or high-speed dispersion, depending on the conditions of use, and then the mixed paint is applied on a glass plate using a wire rod and observed and evaluated with the naked eye. After the coating film dries, if no visible particles are observed by the naked eye, the compatibility of the two is good.
3
Water resistance test: In addition to the requirements on appearance, industrial paints have more stringent requirements on adhesion, weather resistance and water resistance, in order to achieve the purpose of anti-corrosion and anti-rust corrosion. The test method is to put the workpiece coated with color paste industrial paint directly into water and soak it for several days, then take it out and scratch the surface of the workpiece with a tool to observe the surface and the scratch surface.
3 Performance test results
3.1 Paste fineness
The fineness of all the color paste was tested by fineness plate, and the results showed that the fineness of all the color paste was ≦5μm, which meets the requirement of fineness of color paste for industrial paint.
3.2 Color difference of color paste in white washed out color substrate
The 12 pigment color paste was blended into the resin containing white washout agent according to the method described in 2.4 (1), and after making the film, finger grinding was observed as shown in the following picture:
Phase solubility of organic pigments and carbon black in white washout paint
The results show that the phase solubility of the 12 pigment color prizes in the resin containing the diluting agent is excellent.
3.3 Testing of color paste transferability within different resin systems
The 14 pigment color pastes were blended into the resin according to the method described in 2.4 (2), and the film was made and observed as shown in the following figure:
The compatibility of organic pigment color paste and carbon black paste in aqueous hydroxyacrylic resin
The results show that the 14 pigment color prizes have excellent compatibility in the resin.
3.4 Water resistance
The color paste was added into the water-based hydroxy acrylic baking resin, coated with rust-free iron and baked dry to form a film, and then put into the water tank for 7 days, and the film did not appear wrinkled skin, whitening, fog shadow and other phenomena when taken out and observed.
3.5 Alcohol resistance
Use anhydrous ethanol and color paste 1:1 to dilute, and observe whether the pigment is precipitated and flocculated after diluting the color paste.
Diagram of 1:1 anhydrous ethanol diluted color paste after the state
4 Summary
The three dispersants synthesized by polymerization technology were used for the dispersion of waterborne industrial paint slurries, and the resulting slurries were added into the white washout resin and three types of resins, and the results showed that the slurries not only have excellent stability but also have a wide range of phase solubility. Finally, the effect of dispersants on the water resistance of waterborne industrial paints was evaluated, and the results showed that the dispersants had no effect on the water resistance of industrial paints.
