Comparison of the application of the two processes in papermaking products
Time: 2020-12-10 Source from: Titanos
(1) Paper requirements on the performance of titanium dioxide
According to the survey data of China Paper Association, in 2019, there were about 2,700 paper and paperboard manufacturers in China, and the national production of paper and paperboard was 107.65 million tons, an increase of 3.16% over the previous year. Consumption was 107.04 million tons, an increase of 2.54% over the previous year, and the annual per capita consumption was 75 kilograms (1.40 billion people). From 2010 to 2019, the average annual growth rate of paper and paperboard production and consumption is 1.68% and 1.73% respectively.
The paper industry is the third largest user of titanium dioxide, as a paper filler mainly used in high-grade paper and thin paper, in the paper to add titanium dioxide. Can make the paper with better whiteness, good gloss, high strength, thin and smooth, printing without penetration, light quality. Papermaking with titanium white powder commonly used without surface treatment anatase type titanium white powder, can play the role of fluorescent whitening agent, increase the whiteness of paper, but laminated paper requires the use of rutile type titanium white powder after surface treatment, in order to meet the requirements of light and heat resistance.
In the paper industry, because of the production cost, low-end paper generally does not use titanium dioxide, mainly using China clay, talc powder, calcium carbonate, etc., but they will reduce the strength of the paper, increase the weight of the paper. Decorative paper, bible paper, and paper (such as dictionaries, posters, magazine covers, computer, money, copier paper and decorative paper, etc.) must be used in the titanium pigment, use white paper, good whiteness, high strength, luster, thin and smooth, not penetrate when printing, under the condition of same opacity 10 times higher than the calcium carbonate, talcum powder and weight can reduce 15% ~ 30%.
Titanium dioxide is another important application field in papermaking, namely decorative paper, also known as titanium paper, mainly used for making furniture, floors, wallpaper and other raw materials. In China, the amount of titanium white used in decorative paper is much higher than that of other varieties. The amount of titanium white used in decorative paper is 20% ~ 40%, and the amount of titanium white in other papers is 1% ~ 5%. This situation is determined by the level of consumption in our country. Due to the large demand for house decoration and high-grade furniture, the amount of decorative paper gradually rises; Due to the use of titanium white as raw material, the cost of Bible paper is much higher than ordinary paper. In view of the domestic consumption level, the market of Bible paper is very limited. The use of coinage paper is controlled by the state, the amount is relatively stable, will not have an impact on the titanium dioxide market.
As the name implies, decorative paper is paper used for decorative purposes, so its anti-aging products have high requirements, so must use rutile titanium dioxide; More rutile type titanium dioxide is used in high ash paper, this high ash paper must use rutile type titanium dioxide, because anatase type titanium dioxide coverage is not up to the requirements. Anatase type titanium white powder is used in low ash paper, such as bible paper and paper money, bible paper requires paper has a very good opacity, generally use anatase type titanium white can meet; Coinage paper also requires good opacity, mainly using anatase type. Therefore, different paper has different requirements on the performance of titanium dioxide.
(2) Comparison of application of titanium dioxide of two processes in paper products
No matter what kind of paper (base paper), the production process is the same, just according to the paper's final forming demand to choose which process of titanium dioxide different crystal products, the following is the choice of different types of titanium dioxide for different paper products.
Different use of paper products corresponding to the choice of titanium dioxide varieties are also different, rutile titanium dioxide oxidation resistance, good weather resistance, mainly used for decorative paper and weather resistance, high ash paper; Anatase products are used for the weather requirements are not high, poor transparency of low ash paper. Although both chlorination production process process and sulfuric acid production process can produce rutile type titanium dioxide, the whiteness of titanium dioxide produced by the chlorination production process process, the content of rutile crystal, and especially the stability of the finished product are better than the sulfuric acid production process, which is suitable for decorative paper and paper with high ash content. And coin paper and low ash paper must be used in anatase sulfuric acid products, in order to better meet the two kinds of paper to titanium dioxide opacity requirements.
In addition, when we choose titanium dioxide products also need to consider the factors of the paper factory itself, because for the paper factory to decide which titanium dioxide to choose the main reason is the cost of paper, namely the cost of titanium dioxide. Due to cost up to 30 ~ 50% of titanium dioxide in paper making, so the paper mill in meet user requirements, to choose titanium dioxide is haggle over every ounce.