Fiberglass reinforced plastic knowledge point three: color paste

Fiberglass reinforced plastic knowledge point three: color paste

Color paste, as the name implies, is a kind of pigment concentrated pulp, is the use of different pigments, through the pigment surface treatment, surface wrapping and other technologies, developed through rigorous processing technology. According to the different solvents used in color paste, color paste is divided into water-based color paste, oil-based color paste, water-oil general-purpose color paste, etc.; according to the different uses of color paste is divided into paint color paste, adhesive tape color paste, papermaking color paste, textile color paste, machinery color paste, toy color paste, latex products color paste, etc.; according to the different tools used in the use of color paste, the color paste is divided into simple factory color paste and machine color paste, and so on. Color paste in the natural world in concert with dress up the whole world, small to dress up, daily use, toys, etc., large to bridges, houses and buildings, etc., is not to show the colorful colors.

Traditional paint coloring is the use of pigment powder added directly to the paint, or some paint manufacturers themselves simply make the pigment into a paste, and then added to the paint coloring paint. This has certain disadvantages: such as poor color reproducibility, uneven coloring, due to the lack of professional technology and process, the pigment particles are coarse, coloring power is not high, pollution is serious, and added to the paint, the paint film after the light resistance, maroon resistance, easy to fade, chalking and so on.

With the fierce competition in the market, the division of labor is getting more and more fine, the call for high-end coatings is getting higher and higher, in the nineties of the last century, the domestic manufacturers of color paste came into being, and one or two manufacturers specializing in color paste in the beginning; in fact, in foreign countries, there are manufacturers specializing in color paste in the sixties of the last century.

Nevertheless, the quality of color paste products than just the beginning of the product quality has improved a lot, the variety has also been improved, the color paste manufacturers have just started one or two, to today there have been twenty or thirty, mainly distributed in Jiangsu, Zhejiang, Shanghai, Guangdong and other places.

So far, the domestic paint manufacturers basically popularized the use of color paste. General small paint factories, the use of color paste a year, a conservative estimate should be in the amount of 2000-5000 yuan (to the amount of money), medium-sized paint factories in the 5-10 million yuan, large paint factories color paste usage of 500,000-1,000,000 yuan or so. The amount of color paste used by different paint factories varies greatly. In China, there are about 12,000 large and small paint factories, mainly concentrated in the Yangtze River Delta area. With an average of 20,000 yuan/year for each paint factory, the amount of color paste used is about 240 million yuan. And in 2006, the total amount of China’s paint exceeded 5 million tons mark, reached 5,078,400 tons, to 30% of the amount of color paint, per ton of paint color paste usage is about 157.53 yuan, and this is a very conservative data. At present, the domestic color paste factory less than thirty, including imported brand color paste terrific more than thirty. Due to equipment and technology, capital and other restrictions, the real large-scale domestic color paste manufacturers are not many, and the domestic market demand for color paste is far greater than the output of these manufacturers (in addition to architectural coatings color paste, there are rubber products with color paste, PVC products with color paste and other civil, industrial color paste, color paste demand is much larger than the paint), the product is a mixed bag of good and bad quality, the quality of the product is to be further improved.

Application and development of water-based color paste

With the rapid development of construction and industry, including hotels, commercial, landscape, transportation and other color paste areas rarely designed to the field have been significantly into the development of the color paste market, is moving towards a holistic, energy-saving development trend, of course, this is mainly manifested in the rapid rise of the color paste manufacturers, driven by the entire color paste industry tends to be highly efficient, low-carbon development. As an important branch of the paint industry, water-based color paste in the industry, real estate, furniture, home appliances, building materials and home furnishings, driven by the rapid growth of mainstream consumption, water-based color paste in the modern home improvement, home decoration life plays an increasingly important role.

Water-based color paste for coloring, its application areas are very broad, including paint, leather, printing, paper, latex, textile and other industries, the main service object is the paint industry.

1, color paste coloring strength (coloring power)

For the comparison of water-based color paste, coloring strength is an important indicator, which reflects the color concentration of color paste, color spreading performance and pigment dispersion flocculation. The data is measured by the number of parts of pigment paste required for the color to reach 1/25 of the International Standard Depth (ISD), the smaller the value, the higher the color strength. The value represents the number of grams of pigment paste needed to be added to the white base paint: in latex paint – white base paint with 25% titanium dioxide content (1/25ST).

2、Compatibility of color paste (color spreading performance – finger study method)

The compatibility of the color paste with the system is the key to the floating color of the color paint, flocculation and some surface defects of the paint film. Before using the color paste to match the color, must do the compatibility test, additives can often be used to solve the compatibility of the color paste and paint.

Add the color paste to the white paint, generally formulated into medium and light colors, applied to the surface of the coated material or imitation of the surface of the coated material, to be about to condense, use your fingers to grind the surface part of the coating film, after drying, observe whether there is a clear color difference (visual inspection). If the fineness of the color paste is not enough, the dispersing performance is not good all lead to the color paste color spreading is not good, will affect the reproducibility of the color paint.

3、Dispersion performance of color paste (degree of flocculation)

The degree of unflocculation of pigment particles by additives determines the size and stability of color paste dispersion. Generally speaking, it is impossible to achieve complete unflocculation (i.e. the pigment in the system into the original level of particles of uniform and stable existence), just in the form of pigment particles of the appendage uniformly distributed in the system. A good color paste has a rather high degree of deflocculation, that is to say, the agglomerates are as small as possible, so that it has good coloring power, excellent color development and storage stability. Because the dispersion performance of the color paste is not good, the pigment flocculent in the color paste and the white pigment in the base material, filler particles in the migration difference is easier to reflect, this difference often makes the pigment flocculent is no longer uniform distribution, when the film due to the film in the temperature, density and surface tension of the tiny differences in the film, the pigment flocculent and the paint base to participate in this movement naturally, pigment flocculent and then separated, resulting in floating color and hair flower. If the dispersion performance of the color paste is good, the occurrence of floating and blooming can be avoided. The good or bad dispersibility of the paint itself also directly affects the floating and blooming of the color paint.

4, one of the structural properties of the color paste (light resistance, weather resistance)

Color paste light resistance and weatherability test is through outdoor exposure, but the actual outdoor exposure time is too long, the general color paste performance testing is mostly through the instrumentation simulation test.

Light resistance: Use outdoor acrylic emulsion paint to make 1/3ISD and 1/25ISD standard color samples for exposure. Xenon lamp light source (1000W) exposure of 72 hours, the use of 1-8 grade blue wool ruler and the standard color samples at the same time exposure, resulting in color difference to the rating, 1 grade is the worst, 8 grade is the best, (has been assessed by the color measurement software)

Weatherability: Use outdoor acrylic emulsion paint to make 1/3ISD and 1/25ISD standard color samples for exposure. Using ATLAS artificial aging instrument exposure 500 hours, using ISD gray card for color difference rating, 1 level for the worst, 5 levels for the best. (It has been evaluated by the color measurement software)

5、Pigment content of color paste

The pigment content is only for reference, and cannot be used as the index for evaluating the performance of color paste. The coloring power of color paste is not simply proportional to the pigment content. For the same pigment content, there is a big difference in coloring power with different fineness. In order to ensure the stability of the coloring power of the color paste, the pigment content of the color paste is within a certain range of changes in the value of the color paste information provided by the value is a typical reference value.

 

6、Color paste fineness

Fineness is an intuitive index reflecting the coloring power dispersion effect and storage stability of the color paste. Generally for the same pigment color paste, the smaller the particle size, the larger the specific surface area, and thus the covering ability is also increased, the higher the coloring power; the finer the fineness, the higher the luster, the better the dispersion effect and storage stability. Of course, the fineness of the color paste is not the finer the better, because when the particles become smaller, its specific surface area increases, the absorbed light energy increases, the degree of destruction also increases, resulting in a decrease in weather resistance; and particle size is too small in the paint film drying, along with the precipitation of water, the color paste together with the migration of the surface, easy to cause the color is not allowed to match the color and the wall color difference.

7、Compatibility between color paste and paint

Finger research method to take 100 grams of white paint, add 2-3 grams of color paste to be tested, fully stirred, coated on the surface of the coated object, to be about to condense, with a finger to grind the surface layer of the film part of the paint film to be dry, to observe the fingers of the research rubbed and un-raked place whether there is a difference in color, such as the difference between the larger, then the color paste is not good with the compatibility of the test paint, the color paste of this paint mixing out of the paint is prone to produce floating color phenomenon. If the color is the same, generally does not produce floating color phenomenon.

8, the structure of the color paste performance of the second (chemical resistance)

The chemical medium resistance of water-based color paste is mainly acid resistance, alkali resistance, that is, chemical migration resistance. The performance basically depends on the pigment itself, and this factor must be considered in the color paste for outdoor use. Generally water-based paints are also required to be acid and alkali resistant, not organic solvents and other chemicals.

Acid and alkali resistance: According to DIN16524 standard, the acid and alkali resistance of the color pastes are determined by drying (105℃) and placing them in 1% sulfuric acid and 2.5% sodium hydroxide solution for 24 hours respectively, and then removing them and washing them. According to the color bleeding and color changes, according to the 5-level standard to assess, to reach the 5 level indicates excellent acid resistance, alkali resistance, 1 level indicates acid resistance, alkali resistance is very poor.

9、Other physical and chemical parameters of color paste

Density: the unit is grams / cubic centimeter, measured according to the provisions of GB/T1756.

Viscosity: an important indicator to reflect the storage stability of the color paste. (STM- Ⅲ Stormer viscometer)

PH value: PHB-2 portable PH meter to determine the water-based high-quality color paste system of acidity and alkalinity (PH value) is generally between 7-10, so the color paste in the PH value of 7-10 paint system in the color retention, coloring power and color spreading and other performance is excellent.

Fineness and gloss: a visual index reflecting the dispersion effect and storage stability of color paste. Generally for the same pigment color paste, the smaller the fineness, the higher the gloss, the better the dispersion effect and storage stability.

10、Quality stability of color paste

Generally through the strict control of production formula – raw materials – production process – finished products, to ensure the consistency of the solid fraction of the color paste, fineness, viscosity, coloring power, color spreading, light resistance and weather resistance. (Evaluation by color matching software, Lab value and color difference control DE ﹤ 1.0)

The storage stability of general water-based color paste is about 25 ℃ at room temperature for one year without obvious delamination, caking, return to the coarse, precipitation and other defects, and coloring power, color spreading and other physical and chemical properties are not significantly reduced. Usually can be accelerated by hot storage and freezing experiments to determine the aging, through the opening of the can to assess the effect of evaluation and color measurement software assessment.

Selection of color paste should focus on the above factors, other conditions of each brand of color paste can basically achieve and not much difference. Of course, the choice of color paste should also be considered from the economic and environmental protection point of view, such as: the interior wall color paste can be selected to weather some of the color paste, and at the same time, the interior wall as far as possible, do not choose the chromium yellow and other heavy metal-containing color pastes, but should be selected azo, amine and so on.

According to the object of coloring and environmental requirements, the color paste is mainly divided into two kinds of sunlight-resistant and non-sunlight-resistant. Generally, internal use in the system does not exist in the case of compatibility, in order to achieve the color requirements of the lowest cost as a principle, do not require sunlight resistance. And external use must consider the following factors:

a. Light weathering resistance; b. Chemical medium resistance (mainly acid and alkali resistance); c. Compatibility with the use of the system; d. Tinting strength, hiding power and color spreading; e. Matching between the color paste and the color paste f. Storage stability of the color paste;

Generally, the color retention of external coatings is quite strict, so when choosing color paste, especially pay attention to the light and weather resistance and acid and alkali resistance of the color paste. On the premise of good compatibility, coloring power, covering power and color spreading and storage stability, the intermixing of color pastes is also crucial. Should be as far as possible to choose light resistance and weathering performance of single-color color paste color matching, but the fact is often a composite color, so it is best to follow the inorganic and inorganic, organic and organic or light resistance and weathering performance close to the (1/25ST washout, light resistance should be in 7 ~ 8 or 8 levels, weathering should be in 4 ~ 5 or 5 levels) as a principle, so that to ensure that the outdoor color retention, in order to avoid due to the coloring of the color paste weathering performance Obviously different, resulting in a long time caused by fading or uneven color and blossom and other film defects.

 

Translated with DeepL.com (free version)