CN-116790137-B - Preparation method of white pigment with high solar reflectance

Abstract

The invention discloses a preparation method of a white pigment with high solar reflectance, which adopts heterogeneous nucleation principle, takes ethyl titanate as a titanium source, coats barium sulfate with titanium dioxide as an inner core to generate barium sulfate-titanium white composite particles, coats new titanium white with sodium silicate for inactivation, and obtains the white pigment with high solar reflectance through aging, separation, drying and dispersion. The white pigment color pure white Hunter whiteness of the titanium white coated barium sulfate is high, and the high solar reflectance TSR is more than 98% in a wave band of 200nm-2500 nm. Compared with the infrared reflection titanium dioxide with large particle size, the white pigment produced by the invention has the advantages of purer white color, higher reflectance in the visible light region, low decoloring power, 20-40% of the addition amount of the infrared reflection color paste when the white pigment is used for adjusting the color of white paint, more economic product use and higher gross profit space. The invention relates to a barium sulfate-titanium dioxide composite pigment, which has obvious cost advantage.

Inventors

• CHEN SUPING
• LIU ZICHUANG
• SONG YATAO
• QU ZHI

Assignees

• 上海淞叶新材料有限公司

Dates

Publication Date

20260512

Application Date

20230621

Claims (1)

1. 1. The preparation method of the white pigment with high solar reflectance is characterized in that heterogeneous nucleation principle is adopted, ethyl titanate is used as a titanium source, titanium dioxide is coated with barium sulfate by taking barium sulfate as an inner core to generate barium sulfate-titanium white composite particles, sodium silicate is used for coating new titanium white for inactivation, and the white pigment with high solar reflectance is obtained by ageing, separating, drying and dispersing, and the formula process is as follows: Firstly, weighing 6-12 parts of water, 1.00-1.80 parts of dispersing agent and 0.10 part of defoaming agent according to the weight proportion, uniformly mixing in a container, adding 20-35 parts of barium sulfate, uniformly stirring, dispersing at a high speed for 30-40 minutes, wherein the linear speed is 10-23m/s, and supplementing water to 100 parts to obtain the barium sulfate slurry with the concentration of 20-35 wt%; step two, 100 parts of ethyl titanate and 3-10 parts of organic alcohol polyether phosphate are measured and mixed; thirdly, 1000g of barium sulfate slurry is taken and placed in a chemical combination tank, 140-500g of ethyl titanate-organic alcohol polyether phosphate mixed solution is slowly added under continuous stirring, the ethyl titanate is hydrolyzed and adsorbed on the surface of the barium sulfate to deposit and wrap the barium sulfate, so as to generate barium sulfate-titanium white composite particles, and the ethyl titanate-organic alcohol polyether phosphate is added in 30-60 minutes and is continuously stirred for 20-30 minutes; Fourthly, adding water-soluble sodium silicate into the slurry, wherein the amount of the water-soluble sodium silicate is 1-5 percent of that of titanium white calculated by SiO 2 , regulating the pH value to be 8-10 by ammonia water, heating to 80 ℃ and reacting for 3-4 hours at constant temperature; The barium sulfate is precipitated barium sulfate or natural barium sulfate produced by a sulfuric acid method, hunter white is more than or equal to 98, iron impurities are required to be less than 20ppm, the particle size is d10=200 nm, and D90=1200 nm; The barium sulfate is composed of three different particle sizes, wherein barium sulfate A has d50=300 nm, barium sulfate B has d50=700 nm, barium sulfate C has d50=1200 nm, and the weight ratio of the barium sulfate A to the barium sulfate B to the barium sulfate C is between 20 and 25 to 60 to 15 and 20; The dispersing agent for dispersing the barium sulfate is sodium hexametaphosphate, the ethyl titanate is industrial grade ethyl orthotitanate, and the organic alcohol polyether phosphate is isomeric alcohol polyether phosphate; the water-soluble sodium silicate is industrial water-soluble sodium silicate; the prepared white pigment with high solar reflectance has high solar reflectance TSR of more than 98% in a wave band of 200nm-2500 nm.

Description

Preparation method of white pigment with high solar reflectance Technical Field The invention relates to the field of white pigment preparation, in particular to a preparation method of a white pigment with high solar reflectance. Background The rising of the earth temperature encourages the research and development and production of low-carbon, environment-friendly and energy-saving products, near infrared reflective pigments are applied to reflective heat insulation products to prepare high-solar-reflectance products, and high-solar reflective coatings such as real stone paint, multicolor paint, elastic flat paint and the like with higher solar reflectance in the field of paint are more and more popular in the market. Aluminum coil and steel coil are becoming increasingly popular for their end use applications by coating the surfaces of aluminum coil with a coating having a high solar reflectance. The chemical storage tank and the granary adopt high solar reflectance paint, the indoor temperature is low, and the stored chemicals and grains are high in safety. The promotion of a white roof is also in compliance with the requirements of the cold roof era, the air conditioner is reduced, the energy is saved, the carbon emission is reduced, and the grains stored in the granary are ensured not to be fermented at high temperature. The pigment with high solar reflectance in the current market has complete color varieties, and yellow, orange, red, blue, green, black and white. Such color pigments rely primarily on high near infrared reflectance to achieve high total solar reflectance. Such colored pigments are coated, calcined and formed at high temperature, co-precipitated, and the like. The coating is prepared by depositing a pigment capable of selectively absorbing visible light and transmitting infrared rays on a base material with high infrared reflection. If green Cr 2O3 is deposited on the surface of the flaky aluminum powder with high sunlight reflection, the infrared reflection pigment with a core-shell structure, low brightness and low gloss is prepared. The high temperature calcining and synthesizing process adopts metal oxide, nitrate, acetate or even oxide mixed high temperature calcining solid phase reaction, and the metal ion and oxygen radical ion are rearranged at high temperature to form stable composite metal oxide similar to spinel structure or rutile structure, and the pigment is titanium chrome yellow, cobalt blue, iron chrome black, etc. At present, the white pigment with high solar reflectance is infrared reflection titanium dioxide. The infrared reflective pigment W400 of Henschel ALTIRIS (R) changes the solar reflectance by the crystal size. The primary crystal size of the product is 400nm, a large-particle-size titanium dioxide (TiO 2) core, combined silicon dioxide and an aluminum oxide shell are organically modified to obtain a large-size and narrow-particle-distribution titanium white pigment, and compared with common titanium dioxide, the titanium white pigment can reflect a larger proportion of near infrared light, and meanwhile high hiding power and tinting strength are maintained. PFR-404 of Japanese stone origin has excellent near infrared reflectivity, and titanium dioxide IR-1000 of Jiangsu generalized chemistry in China is infrared reflective titanium white prepared by a sulfuric acid method. The high solar reflectance white pigments currently on the market are mainly these types-large particle size titanium white with excellent near infrared reflection. The American Hunsman infrared reflection titanium dioxide has three products, namely Gao Xiaose force, medium decoloring force and low decoloring force, and secondly, the Japanese stone original PFR-404 is a product with excellent near infrared reflection performance and medium decoloring force. Total Solar Reflectance (TSR) =uv reflectance+visible light reflectance+ir reflectance, high Total Solar Reflectance (TSR) materials can be achieved with good reflection in the uv, visible and near infrared regions. The common titanium dioxide has good reflection in ultraviolet and visible light regions, but has low reflection in near infrared regions. The original grain diameter of the titanium white is increased, more infrared rays are prevented from being transmitted, and the total solar reflectance TSR is improved. The infrared reflection titanium white pigment of U.S. Hensman has larger grain size than conventional titanium white pigment, and has very high near infrared reflectance, but when the grain size of the pigment is increased, the whiteness is reduced to be yellow red, the whiteness is darkened, the whiteness is reduced to be absorbed in a visible light region so as to influence the reflection in the visible light region, the titanium white particle is increased to sacrifice whiteness and increase the cost, and the total solar reflectance is not ten-thousandth by increasing the grain size of the titanium white. Disclosure