barium sulfate manufacturer

Application of Modified Precipitated Barium Sulfate M-1001A in White Gloss Paint

Lu Yunzhu, Fang Chang, Fang Lifu

Yunfu Hongzhi New Materials Co., Ltd.

Abstract: The reflectivity, oil absorption, viscosity, whiteness, specific gravity and other performance indexes of modified precipitated barium sulfate are similar to those of titanium dioxide. Therefore, by taking advantage of its advantages, 10% of the total amount of titanium dioxide is compounded with it. According to the comparative data of viscosity, dispersibility, glossiness, covering power, weatherability and other important performance indexes, it can be seen that the application of modified precipitated barium sulfate in white varnish can not only reduce the dosage of titanium dioxide, but also keep the original characteristics of titanium dioxide to the maximum extent, and promote the dispersion, leveling, weatherability and whiteness of the whole formula system, thus achieving the real purpose of using modified precipitated barium sulfate M-1001A.

Key words: modified precipitated barium sulfate, titanium dioxide, covering power; weather resistance, dispersibility

Introduction

In recent years, the increase of prices has become one of the important topics discussed in the industry. In the coating industry, titanium dioxide, as an indispensable white pigment, occupies an important position. And its soaring has undoubtedly brought great impact to the coating industry. At this time, reducing costs and increasing efficiency and maintaining the original performance have become the top priority of the work.

At present, there are many extender pigments (fillers) on the market, while middle and high-end companies in the coatings industry are gradually choosing modified precipitated barium sulfate to replace part of the titanium dioxide for coating formulations. This not only reduces the amount of titanium dioxide, reduces the cost, but also allows the excellent performance of modified precipitated barium sulfate to be demonstrated, which is recognized by the industry.

1 Part of the experiment

1.1 Main raw materials

Waterborne acrylic resin：8401, commercially available products

Modified precipitated barium sulfate：M-1001A，Yunfu Hongzhi New Materials Co.,Ltd.

Ordinary precipitated barium sulfate：particle size 1.0µm（D50）,commercially available products

Titanium dioxide pigment：R706, DuPont

Leveling agent：BYK306，BYK-Chemie GmbH

Defoamer：TEGO904W, Evonik Industries AG

Dispersant：BYK190, BYK-Chemie GmbH

2-Butoxy ethanol：analytical reagent, commercially available products

Glass bead：1.0mm, commercially available products.

1.2 Physical properties of product and electron micrograph

Table 1 Physical property comparison table

1.3 Main equipment

High-speed dispersion machine：SFU400，Shanghai Weite Electric Machinery Co.,Ltd.

Electronic scale：JM-B-3003，0.01g，Zhuji Chaoze Weighing Apparatus Equipment Co.,Ltd.

Scraper fineness meter：QXD-50，Tianjin Jingke Material Testing Machine Co., Ltd.

Scraper fineness meter：QXD-100，Tianjin Jingke Material Testing Machine Co., Ltd.

Four-sided applicator：SZQ（100-150-200-250µm），Guangzhou Demanyi Instrument Co.,Ltd.

Digital display rotary viscometer：NDJ-8T，Shanghai Fangrui Instrument Co.,Ltd.

Three-angle light meter：CS380，Shanghai Liangyan Intelligent Technology Co., Ltd.

Xenon lamp aging test chamber：SD-Z-150A，Dongguan Hui Tai Machinery Co., Ltd.

Spectrophotometer：KONICA MINOLTA Spectrophotometer CM-2300d，Konica Minolta Holdings, Inc.

2 Experimental method of modified precipitated barium sulfate M-1001A used in white gloss paint

2.1 The basic formulation process of titanium dioxide

Firstly, disperse acrylic resin, titanium dioxide, modified precipitated barium sulfate, dispersant, defoamer, and 2-Butoxy ethanol with a disperser at 1000 revolutions for 20 minutes to fully wet the slurry. Then add glass beads (slurry: glass beads=1:1), grind and disperse at a high speed of 2000r/min for 60 minutes, and wait until the fineness reaches 15-20μm.

Table 2 The basic formula of titanium white paste

2.2 The basic formula process of white gloss paint

Mix the above ground slurry with the water-based acrylic resin in a certain proportion, and stir evenly at 1200r/min to prepare the paint to be tested.

Table 3 The basic formula process of white gloss paint

2.3 The production of experimental comparison model

Prepare the paint film of the color paint to be tested on the transparent glass sheet with a 150µm coater, dry it naturally for 30 minutes, then put it in a 60℃ oven for drying and curing for 60 minutes, then take it out and cool it to room temperature before testing.

3 Results and discussion

3.1 Comparison of viscosity

By preparing the basic formula of titanium white paste in Table 2 and the basic formula of white lacquer in Table 3, the viscosity value was tested under the same conditions, and the test conditions (30 revolutions/3# rotor/25°C). The experimental test results are shown in Table 4.

Table 4 Comparison of viscosity data

Fig.3. Viscosity data comparison chart

From Table 4 and Figure 3, it can be seen that the viscosity of modified precipitated barium sulfate M-1001A is obviously reduced compared with pure R706 titanium dioxide, which can improve some adverse effects caused by high viscosity. It is helpful for some coatings with high solidity and low viscosity. However, with the addition of ordinary barium sulfate, the viscosity decreases slightly, but the viscosity reduction effect is not obvious.

3.2 Comparison of dispersion

According to the basic formula of titanium dioxide color paste in Table 2, the change of dispersion fineness was observed at the same rotational speed and different time. The experimental results are shown in Table 5.

Table 5 Comparison of dispersion

Fig.4. Comparison chart of dispersion fineness

It can be seen from Table 5 and Figure 4 that the titanium dioxide slurry with the addition of modified precipitated barium sulfate M-1001A and ordinary barium sulfate, under the premise of the same dispersion speed, adding M-1001A can improve the dispersion of the slurry, shorten the dispersion time and improve dispersion efficiency. Then pay attention to the data of titanium dioxide slurry with ordinary barium sulfate, not only did not improve, but also had a negative effect.

3.3 Comparison of gloss

According to the above experimental methods, the effects of different barium sulfate on the gloss of paints are compared, and the experimental results are shown in Table 6.

Table 6 Comparison of gloss

Fig.5. Effect comparison chart of glossiness

Combining Table 6 and Figure 5, it can be seen that the white paint added with modified precipitated barium sulfate M-1001A has no obvious difference in gloss compared with the white paint of pure R706. It not only maintains the original performance of R706, but also improves the leveling effect and scratch resistance. The white paint with ordinary barium sulfate has a slight decrease in gloss, and the surface effect is not ideal.

3.4 The effect and data comparison of hiding power

The L, a, b values and whiteness values of different boards were analyzed and tested by using a spectrophotometer. The experimental results are shown in Table 7.

Table 7 Comparison of the results of L, a, b value and whiteness value

Fig.6. Chromatographic curve effect diagram

Fig.7. The comparison chart of hiding power

Combined with the data in Table 7, it can be seen from Figure 6 and Figure 7 that compared with pure R706 white paint, white paint with modified precipitated barium sulfate M-1001A not only has no influence on hiding power, but also improves whiteness to a certain extent. However, the white paint added with ordinary barium sulfate has obviously decreased hiding power and dim color, which has a certain influence on R706.

※ Additional explanation of L, a, b values

Fig.8. The explanation of L, a, b values

L means black and white, + means white, -means dark,

a means red and green, + means reddish, -means greenish,

b means yellow-blue, + means yellowish ,-means blueish.

3.5 Comparison of weather resistance results

Using xenon lamp aging test chamber, 6 hours anti-aging test was carried out on different samples, and the gloss change of paint film was compared. The experimental comparison data are shown in Table 8 and Table 9.

Table 8 Gloss before weather resistance test

Table 9 Gloss after weather resistance test

Fig.9. Comparison chart of gloss change curve of weather resistance test

Fig.10. The comparison chart of weather resistance effect

Combined with the data in Tables 8 and 9, it can be seen from Figures 9 and 10 that the white paint with modified precipitated barium sulfate M-1001A is almost the same as that of pure R706 in terms of weather resistance. At the same time, it also shows that the weather resistance after the combination of the two is excellent. However, the white paint added with ordinary barium sulfate has obviously decreased glossiness and deteriorated surface effect.

4 Experimental results

4.1 In white gloss paint, adding modified precipitated barium sulfate M-1001A can effectively reduce the viscosity of the paint, and play a decisive auxiliary role in the application of high-solid and low-viscosity paint.

4.2 In white gloss paint, adding modified precipitated barium sulfate M-1001A can promote the dispersion of titanium dioxide pigments, reduce grinding time and improve timeliness.

4.3 After adding the modified precipitated barium sulfate M-1001A component to the white gloss paint, the leveling property of the paint film is improved, the gloss is high, the mirror effect is good, and the scratch resistance of the paint film is also improved.

4.4 In the white gloss paint, after adding the modified precipitated barium sulfate M-1001A component, it not only has no effect on the hiding power, but also improves the whiteness to a certain extent, the color is bright, and the gloss and color retention are good.

4.5 Using modified precipitated barium sulfate M-1001A to replace part of the titanium dioxide pigments within an appropriate range will not affect the excellent properties of the original color paste and color paint. It has better weather resistance, and also has the effects of preventing floating and blooming and flocculation, and has good stability.