纸张干法涂料的制备及其性能研究

Perparation and Characteristics of Water-free Coatings Used in Dry Surface Treatment of Paper

采用超临界流体法制备了聚(甲基丙烯酸甲酯/丙烯酸丁酯)/CaCO3(PMMA/BA/CaCO3)无水相涂料,并对纸张表面进行干法涂布处理。首先探讨了反应体系中BA质量浓度、反应温度、反应时间对共聚反应转化率和共聚物(MMA/BA)分子质量及其分布的影响,然后通过GPC、FT-IR、TGA、DSC等分析检测技术对无水相涂料进行了表征。实验表明,随着BA质量浓度的增加,共聚物的分子质量降低,而其分布变宽;当共聚反应的温度为75℃、时间为10 h、单体MMA与BA的质量比在84/16～76/24之间时,共聚反应的转化率达80%左右,同时共聚物的相对分子质量为(2.7～3.6)×104;随着BA质量浓度的增加,MMA/BA共聚物的玻璃化转变温度逐渐降低,通过调节MMA与BA的质量比可以控制共聚物的玻璃化转变温度,使其具有满足纸张涂布压光及成膜对涂料性能要求的玻璃化转变温度及耐热性能。

Poly（ methyl methacrylate/butyl acrylate）/nano-CaCO3 （PMMA/BA/CaCO3 ） water-free coatings were prepared via free radical copolymerization of MMA and BA in the presence of nano-calcium carbonate as pigment in super critical carbon dioxide （ sc-CO2 ）. Then, the （PMMA-BA）/nano-CaCO3 water-free coatings were used in the dry surface treatment （DST） of paper. The reaction conditions of copoly- merization were researched, and the characteristics of the water-free coatings were studied by using FT-IR, SEM, TGA and DSC. The exper- imental results showed that the molecular weight of copolymer decreased and molecular weight distribution became wide with the increase of BA monomer concentration, and the copolymerization conversion rate was higher and reached to about 80% when the reaction temperature was 75℃, the reaction time 10 h, and the mass ratio of MMA/BA between 84/16 and 76/24, meanwhile the molecular weight of copolymer was （2.7 -3.6） × 104, which was suitable for DST of paper. The glass-transition temperature of water-free coatings decreased with the in- crease of BA monomer concentration, therefore, an ideal glass-transition temperature of water-free coatings could be achieved by adjusting the mass ratio of MMA to BA.