ZHOU Yuan1 , WANG Sheng-fu2 , CHE Wen-bo2 (1. Marine Chemical Research Institute Co., Ltd., Qingdao 266071, Shandong, China; 2. Qingdao Dayang-Haiderun Building Materials Co., Ltd., Qingdao 266108, Shandong, China)
Abstract: Preparation process and the methods of water-in-water multicolor coatings were introduced. The affecting factors on the coatings properties and some existing problems were analyzed. Prospects of the application were forecasted.
multicolor coatings is a new type of decorative paint. Compared with granite marble and real stone paint, it has many advantages such as realistic simulation, excellent performance, simple construction technology, relatively low cost, no environmental pollution, etc., and can replace Granite and other stones reduce the mining of natural stones and avoid the danger caused by the fall of natural stones. multicolor coatings can be divided into 4 categories: oil-in-oil, water-in-oil, oil-in-water, and water-in-water. With the increase of people’s requirements for water-based, the first three categories have been basically eliminated, and water-in-water multicolor coating has become a research hotspot. Water-in-water multicolor coating is composed of incompatible two-phase components. One phase of the dispersion medium is a continuous phase and the other phase is a dispersed phase. Two or more colored particles with different colors, sizes, and shapes are uniform. Ground suspension in a dispersion medium containing a stabilizer, composed of a composite suspension dispersion coating. The film formation process is shown in Figure 1. Among them, high-viscosity, high-concentration colorful component phases can be suspended in low-viscosity and low-concentration phases. After coating, dispersion occurs to obtain a variety of color pattern effects. It can also have unevenness, strong three-dimensionality, and elegant embossed relief. The appearance texture effect is shown in Figure 2. “Environmental protection, elegance, energy saving” water-in-water colorful coatings are favored by the market for their multifunctionality and high decorativeness, and they are a new type of environmentally friendly coating materials with great potential.In the development of water-in-water multicolor coatings, the stability of colored particles (including mechanical stability and storage stability) is one of the main problems. The colored granules should not settle during storage, be insoluble with water and insoluble with each other, and maintain their independence. In addition, the size of the colored particles is not easy to control. This paper develops a water-in-water multicolor coating. The hardness of the paint particles can be adjusted freely, the leveling of the colored particles after drying can be adjusted freely, the uneven pattern and flat pattern can be adjusted freely, and the product stability can reach 1 ～ 2 a.
1 Test section
1.1 Test materials
Emulsion M-06, Emulsion M-02, Color Particle Gel Agent DC30, Color Particle Protective Glue, Kaolin, Titanium Dioxide R930, Film-forming Aid TE, Multi-functional Auxiliary AMP-95, Antifoaming Agent, Fungicide Thickener, propylene glycol, ammonia, water.
1.2 Test formula
The formulation of multicolor coating should make the paint meet the following requirements: stable storage, good comprehensive physical properties of the coating film, raw materials should be as easy as possible, cost should be as low as possible, and the preparation process should be as simple and easy as possible.
1.2.1 Preparation of base paint
First add water, kaolin, titanium dioxide R930, DC2, and defoamer in order, and stir at medium speed for 10 minutes until completely dispersed. Then add the multifunctional auxiliary AMP-95 to increase the viscosity and disperse for 20 minutes at high speed; then add the fungicide, emulsion M-02, film-forming aid TE, 7% DC30, and disperse at high speed for 20 minutes. Packaging is ready for use. See Table 1 for the formulation of the base paint.
1.2.2 Preparation of base material
First, the thickener and water are mixed beforehand, and the pH value is adjusted to 8-9 with ammonia water. Then add emulsion M-06, film-forming aid TE, propylene glycol, and defoamer in order, and stir well. Finally, add the fungicide to disperse for 20 minutes, and pack it for use. See Table 2 for the formulation of the base material.
1.2.3 Preparation of colored particles
Mix the base paint with color paste into base paints of various colors. After adding 7% DC30 medium, stir at a low speed (the rotation speed gradually increases from 200 r / min to 600 r / min) to stir up the appropriate-sized colored particles. Sodium phosphate thickens. The formula of the colored particles is shown in Table 3.
1.2.4 Preparation of multicolor coating
First dilute the protective granules with water 1: 1, then add them to the colored granules, stir and then add the base material and disperse for 20 min. The colored paint is dispersed, and is wrapped with protective glue and separated from each other to form a stable dispersion and finished product packaging. See Table 4 for the recipe of multicolor coating. The process diagram is shown in Figure 3.
1.3 Performance test
According to HG / T 4343—2012 “Water-based colorful architectural coatings”, the water-in-water colorful coatings are tested for performance. The results are shown in Table 5.
2 Results and discussion
2.1 Influence of film-forming substances
The film-forming substance is the main substance that constitutes the coating to form a continuous three-dimensional network structure coating film, and is the key material that determines the physical and chemical properties of the coating film. The film-forming materials used in colorful coatings can be styrene-acrylic, pure acrylic, silicone-acrylic, fluorosilicone emulsions, etc. Since the functional groups or emulsifiers in most emulsions are often adsorbed or reacted by other additives, they usually destroy “card “House” structure, the appearance of bleaching and bleeding; the emulsion in the base paint reacts with the protective glue, causing the particles to gradually expand, resulting in uneven granulation batch; in the continuous phase, the emulsion and the protective glue react to form paint flocculation or after The emulsion is incompatible with the protective glue system and has poor stability, which exacerbates the foaming, whitening phenomenon of the coating film and is difficult to recover. Therefore, whether to choose an emulsion with good compatibility with the protective glue is very important for the stability of water-based colorful coatings. . The compatibility between the emulsion of the base paint (dispersed phase) and the finished paint (continuous phase) in the multi-color coating system is also very important. If it is not selected correctly, the system will have severe delamination or post-thickening, resulting in The finished product failed. In the test, the elastic emulsion M-02 was selected as the film-forming substance of the base paint, which was matched with the emulsion M-06 in the finished coating. The water-based colorful coating was produced. The granulation softness and hardness could be adjusted freely, the particles were uniformly dispersed, and the storage stability was good .
2.2 Effect of colored particle protective glue
The type of colored particle protective gel and the concentration of the gel solution are very important for the colored particle stability of colorful coatings. At the same time, the amount of protective glue determines the leveling of the colored particles after drying. In order to maintain a certain shape and size of colored particles in the coating system for a long period of time, and to achieve non-blocking, crushing, and color mixing, it is necessary to choose a protective glue that matches the coating system. In this test, a high-purity deionized silicate compound is used as the protective paint for color particles. It is insoluble in water but can hydrate and expand in water to form a colorless transparent liquid. When the amount is 5% to 8% in water, it can be used. Keep flowing for 24 h. With a small amount of electrolyte, it can quickly form a very strong thixotropic and thickening effect.
2.3 Effect of additives
The amount of additives used in coating production is generally not large, but can give coatings special properties. Correct selection of additives can improve production efficiency and product quality, make granulation perfect, storage stable, easy to apply, and the coating film is flexible and plump. It can also expand product applications and improve the construction performance of coatings. This test mainly uses the following: gelling agents, dispersing agents, defoaming agents, film-forming aids, thickeners, fungicides, pH adjusters, etc. These additives have good compatibility in water-based colorful coating systems. .
2.4 Analysis of common problems of multicolor coating
The multicolor coating system is complex. The correct choice of raw materials and reasonable mix ratios are the key to the preparation of multicolor coatings and the guarantee of the quality of multicolor coatings. multicolor coatingss often have some problems during paint making and storage, transportation and construction, as well as during the painting stage. The occurrence of these problems is closely related to the paint’s formulation components, as shown in Table 6.
In order to ensure product quality during the manufacturing process of multicolor coatings, the following issues need to be paid attention to: (1) Control of the stirring speed during the manufacturing process. (2) Color matching. Because it is composed of similar colors of marble, pay special attention to color matching. (3) The spray gun is critical, and the caliber of the spray gun is determined. (4) Construction repeatability is good. As for the simulation of granite and marble, it is not enough that the laboratory model is done well. When large area construction is required, the color should be as simple as possible.
With the vigorous development of domestic decorative coatings, the demand for environmentally-friendly decorative coatings, especially high-grade, high decorativeness and high technical content, will become more urgent. Water-in-water multicolor coating can provide different fancy marble patterns with different patterns and sizes according to different material surfaces and according to customer needs. It can be widely used in hotel, office building, residential, school, hospital exterior walls. It can also be used on the surface of metal and wood. It can also be applied to the surface of ceramics, lamps, furniture, sculptures, handicrafts, etc. After the decoration, the surface is not only lively and generous, but also elegant and solemn. Water-in-water multicolor coating is a new type of environmentally friendly paint with potential and in line with the future development direction of paint, with its excellent coating supporting performance and cost performance, and has a broad market application prospect.