| With the economic development, the requirement of coated paper increases greatly.Paper coating is an important process which is used to improve the appearance andprintability of paper. Paper with light weight, high brightness and opacity and high sheetgloss are the development direction. In the manufacture of paper, pigments that impartgood opacity to the product are important. Various kinds of pigment are exploited in thepaper industry. Plastic pigment, an organic pigment, has some unique features comparedto traditional inorganic pigments, such as low density, high opacity and sheet gloss,which are suitable for the light weight coating. The main benefit of plastic pigments inpaper coating is their impact on optical properties, sheet gloss and print qualityperformance. The calendar response of coated paper can also be improved and resultedin less severe calendar conditions.In this thesis, the hollow plastic pigment was prepared by the soap-free seededemulsion polymerization. This pigment has a polyacrylate core and polystyrene shell(PA/PS). It turned into hollow structure when it was treated with alkali/cooling method.In alkali treatment process, the optimum treatment time was3h, at95℃a pH of12. Theprepared pigment was characterized by using TEM, FTIR and DLS. The hollowstructure can be clearly observed by the TEM images. The average diameter of theemulsions were obtained and show a small uniformity.The prepared plastic pigment was applied in the paper coating to replace theconventional mineral pigment, clay and calcium carbonate, which are the mostcommonly used in paper coating. The results showed that paper properties, includingbrightness, opacity, sheet gloss and K&N were all improved by using plastic pigment.With the increase of the plastic pigment dosage, the brightness, opacity, sheet gloss andK&N were increase. Considering the price of the plastic pigment,10%in the pigmentformula is enough for the paper printing properties. |
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