scholarly journals The Effect of a Polymer-Stabilized Latex Cobinder on the Optical and Strength Properties of Pigment Coating Layers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 568
Author(s):  
Zhenghui Shen ◽  
Araz Rajabi-Abhari ◽  
Kyudeok Oh ◽  
Sooyoung Lee ◽  
Jiachuan Chen ◽  
...  

Coated paper with a porous coating layer may have enhanced light-scattering ability and thus favorable optical properties. However, the increased porosity of such a coating layer is likely to decrease the strength of the coated paper, thereby adversely affecting the quality of the paper in the printing and converting processes. In this research, polymer-stabilized (PS) latex was prepared and used as a cobinder for the pigment coating of the paper. The PS latex particles were colloidally stabilized by a 3:1 mixture of starch and polyvinyl alcohol. The influence of the PS latex cobinder on the viscosity, sedimentation, and consolidation of coating colors was investigated. In addition, the effect of the cobinder on the properties of coating layers, namely, their porosity and surface, optical, and tensile properties, was examined. The results revealed that the PS latex cobinder formed microstructures in the coating colors and affected their viscosity. The addition of PS latex also led to enhanced interactions between coating color components, which affected the consolidation of the coating color, resulting in the formation of dried coating layers with greater porosity and improved optical properties (i.e., higher brightness and opacity) relative to coatings without the PS latex cobinder. Furthermore, the addition of PS latex improved the tensile strength of the coating layers, which was attributable to the small size and the polymeric protective shell of the cobinder particles. Thus, these results show that this PS latex cobinder has the potential to be used for the production of high-quality coated paper products.


Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 12
Author(s):  
Petronela Nechita

Coatings based on pigment and polymer binders are applied on paper surfaces to improve their surface, optical, and printing properties. Besides the coating composition, the structure and properties of the coated papers are influenced by the coating layer consolidation upon drying. In this study, the influence of drying conditions on the structure and properties of coating layers based on natural pigments (clay) and polymer binders (butadiene acrylonitrile latex) has been analyzed. Using a laboratory rod Mayer device, the coatings were applied as thin layer (about 15–16 g/m2) on the paper surface and samples of coated paper were dried at 20 and 105 °C temperatures. The optical, structural, and water absorption properties of the coating layer were evaluated by the measurement of gloss, opacity, void fraction, light scattering, and contact angle. The obtained results highlighted that both the drying temperature and latex content in the coating color have a synergic effect on the coated paper quality.



2014 ◽  
Vol 884-885 ◽  
pp. 212-215
Author(s):  
Ying Li ◽  
Wen Juan Gu ◽  
Bang Gui He

The physical structure of coating layer have an important influence on transferring and setting of the printing ink. In this study, the effect of pigment on surface microstructure and surface free energy was investigated. The findings indicated that the pigment affected the pore size, depth and distribution of the coated paper surface. Kaolin pigment compared with calcium carbonate pigment was good to improve the paper surface smoothness. Surface free energy of kaolin pigment coating was higher than calcium carbonate pigment coating, which showed that surface wettability of coating with kaolin pigment was better than calcium carbonate pigment.



2011 ◽  
Vol 236-238 ◽  
pp. 1178-1182
Author(s):  
Yan Xin Liu ◽  
Yu Long Wang ◽  
Shen Tao Qin ◽  
Fei Fei Liu

Coating pore structure of low gloss coated paper based on different pigment blends was analyzed using mercury intrusion method in this paper. The results show that pore size of coating layer structure of low gloss coated paper ranges from 20nm-500nm, and the range from 500nm-5000nm is mainly from base paper and interactions between coating color and base paper. Printability of coated paper can be well related with coating pore structure. Print gloss is strongly influenced by pore size and pore volume. Large pore diameters and small pore volume of coating layer structure can improve print gloss. Ink density increases with the increasing of pore diameter while the pore volume is kept constant. The increasing of pore volume of coat layer structure will improve capillary absorption and then improve ink absorption. The control of coating pore structure is very important for producing low gloss coated paper.



2014 ◽  
Vol 881-883 ◽  
pp. 1439-1442
Author(s):  
Ying Li ◽  
Wen Juan Gu ◽  
Bang Gui He

The surface topography and properties of coating layer have an important influence on penetration and distribution of the print ink. In this research, the main objective was to investigate the effect of binder migration on the coating surface microstructure. The surface microstructure was explored in the method of numerical and visual analysis using mercury porosimetry measurement, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The findings indicated that the binder migration on the coating surface affected the pore size, depth and distribution of the coated paper surface. The little binder migration in the consolidation phase of coating color made a contribution to the forming of the coating layer, which made the coating surface more smother to printing performance.



2012 ◽  
Vol 27 (2) ◽  
pp. 466-471
Author(s):  
Patrick Huber ◽  
Laurent Lyannaz ◽  
Bruno Carré

Abstract Production of lightweight coated paper (LWC) utilises more and more deinked pulp (DIP), for both economical and environmental reasons. A critical requirement on DIP quality for such grades is the cleanliness of the pulp. Indeed, the coating layer may not fully cover specks in the base paper. The objective of this work was to determine the required specifications of the coating layer to produce LWC with DIP base paper. The specks masking phenomena by the coating layer was studied from both optical measurements on coated handsheets made from DIP, and computer simulations of specks contrast reduction. The impact of coating layer parameters (coat weight and optical properties), base paper parameters (grammage and optical properties) and specks nature (grammage and optical properties) on specks masking is studied.



2013 ◽  
Vol 791-793 ◽  
pp. 286-289
Author(s):  
Zhao Hui Zhen ◽  
Zheng Shun Wang

The coating binder migration and concentration in z-direction of coating layer especially in coating surface influence the coated paper printing properties. The results indicated that with the increase of coating surface binder migration, the coated paper opacity decreases, and the K&N value decreases. The relationship of K&N value and binder concentration in surface of coating layer was linear, which indicated that compared to binder dosage concentration in coating color, the K&N value and coating surface binder concentration has higher correlation. The more uniform the binder distribution in cross section of coating layer, the greater the IGT.



2013 ◽  
Vol 746 ◽  
pp. 114-117
Author(s):  
Zhao Hui Zhen ◽  
Zheng Shun Wang

The coating binder migration and concentration in z-direction of coating layer especially in coating surface influence coated paper optical properties. The results showed that with the increase of coating surface binder migration, the calendaring gloss decreases, the printing gloss and the printing optical density increases. The calendaring gloss and printing gloss, compared to the influence of binder distribution in coating layer,seemed more subject to coating surface binder concentration. Binder in the coating surface concentration and distribution in z-direction almost did not affect the whiteness of coated paper.



TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.



TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.





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