Cracking at the fold in double layer coated paper: the influence of latex and starch composition

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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Microstructure and Mechanical Properties of Vacuum Plasma Sprayed HfC, TiC, and HfC/TiC Ultra-High-Temperature Ceramic Coatings

Materials ◽

10.3390/ma13010124 ◽

2019 ◽

Vol 13 (1) ◽

pp. 124

Author(s):

Ho Seok Kim ◽

Bo Ram Kang ◽

Seong Man Choi

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Single Layer ◽

Ceramic Coatings ◽

Hafnium Carbide ◽

Vacuum Plasma Spraying ◽

Vacuum Plasma ◽

Coating Layers ◽

Hardness Values ◽

Ultra High Temperature

To improve the oxidation resistance of carbon composites at high temperatures, hafnium carbide (HfC) and titanium carbide (TiC) ultra-high-temperature ceramic coatings were deposited using vacuum plasma spraying. Single-layer HfC and TiC coatings and multilayer HfC/TiC coatings were fabricated and compared. The microstructure and composition of the fabricated coatings were analyzed using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The coating thicknesses of the HfC and TiC single-layer coatings were 165 µm and 140 µm, respectively, while the thicknesses of the HfC and TiC layers in the HfC/TiC multi-layer coating were 40 µm and 50 µm, respectively. No oxides were observed in any of the coating layers. The porosity was analyzed from cross-sectional images of the coating layers obtained using optical microscopy. Five random areas for each coating layer specimen were analyzed, and average porosity values of approximately 16.8% for the HfC coating and 22.5% for the TiC coating were determined. Furthermore, the mechanical properties of the coating layers were investigated by measuring the hardness of the cross section and surface roughness. The hardness values of the HfC and TiC coatings were 1650.7 HV and 753.6 HV, respectively. The hardness values of the HfC and TiC layers in the multilayer sample were 1563.5 HV and 1059.2 HV, respectively. The roughness values were 5.71 µm for the HfC coating, 4.30 µm for the TiC coating, and 3.32 µm for the HfC/TiC coating.

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Application of Chitosan as a Barrier Coating on Coated Ivory Board

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.200.180 ◽

2012 ◽

Vol 200 ◽

pp. 180-185 ◽

Cited By ~ 3

Author(s):

Zhi Qiang Fang ◽

Gang Chen ◽

Yu Sha Liu ◽

Xin Sheng Chai

Keyword(s):

Water Vapor ◽

Double Layer ◽

Transmission Rate ◽

Single Layer ◽

Barrier Properties ◽

Vapor Permeability ◽

Oxygen Barrier ◽

Coated Paper ◽

Oxygen Transmission Rate ◽

Coating Weight

Chitosan solution was applied to coated ivory board as a barrier material, and the surface microstructure, oxygen resistance and water vapor permeability of chitosan-coated paper under different coating weight were studied. According to the images of scanning electron microscope(SEM) and Atomic force microscope(AFM), the coated ivory board surface has a smooth contour without pores and cracks after coating with chitosan. Increasing in coating hold-out of chitosan, the smoothness and the oxygen barrier properties of coated paper were improved considerably, but no improvement on water vapor resistance. An Oxygen transmission rate (OTR) of 119.0 cm3/m2•24h•0.1MPa was obtained when the coating weight of chitosan was 3.96 g/m2. Single-layer and double-layer techniques were used to coat coated ivory paper with chitosan; it was found that the OTR of paper, obtaining by double-layer coating technique, was lower than that of single-layer paper at similar coating weight. For the purpose of reducing water vapor transmission rate (WVTR) of chitosan-coated paper, Poly(vinyldene chloride)(PVDC) was applied on the chitosan-coated paper. Water vapor and oxygen barrier properties were enhanced as the coating weight of PVDC increased from 1.05 g/m2to 7.40 g/m2. While the chitosan and PVDC was coated on coated ivory paper through bi-layer technique for 1.96 g/m2and 7.40g/m2, respectively, the WVTR and OTR of paper decreased by 66.3% and 98.0% separately, compared to that of the chitosan-coated paper for 1.96g/m2.

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Preparation of SA–PA–LA/EG/CF CPCM and Its Application in Battery Thermal Management

Nanomaterials ◽

10.3390/nano11081902 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1902

Author(s):

Ziqiang Liu ◽

Juhua Huang ◽

Ming Cao ◽

Yafang Zhang ◽

Jin Hu ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Phase Change ◽

Phase Change Material ◽

Thermal Management ◽

Double Layer ◽

Temperature Control ◽

Single Layer ◽

Mass Ratio ◽

Change Material

To improve the heat dissipation efficiency of batteries, the eutectic mass ratios of each component in the ternary low-melting phase change material (PCM), consisting of stearic acid (SA), palmitic acid (PA), and lauric acid (LA), was explored in this study. Subsequently, based on the principle of high thermal conductivity and low leakage, SA–PA–LA/expanded graphite (EG)/carbon fiber (CF) composite phase change material (CPCM) was prepared. A novel double-layer CPCM, with different melting points, was designed for the battery-temperature control test. Lastly, the thermal management performance of non-CPCM, single-layer CPCM, and double-layer CPCM was compared via multi-condition charge and discharge experiments. When the mass ratio of SA to PA is close to 8:2, better eutectic state is achieved, whereas the eutectic mass ratio of the components of SA–PA–LA in ternary PCM is 29.6:7.4:63. SA–PA–LA/EG/CF CPCM formed by physical adsorption has better mechanical properties, thermal stability, and faster heat storage and heat release rate than PCM. When the CF content in SA–PA–LA/EG/CF CPCM is 5%, and the mass ratio of SA–PA–LA to EG is 91:9, the resulting SA–PA–LA/EG/CF CPCM has lower leakage rate and better thermal conductivity. The temperature control effect of single-layer paraffin wax (PW)/EG/CF CPCM is evident when compared to the no-CPCM condition. However, the double-layer CPCM (PW/EG/CF and SA–PA–LA/EG/CF CPCM) can further reduce the temperature rise of the battery, effectively control the temperature and temperature difference, and primarily maintain the battery in a lower temperature range during usage. After adding an aluminum honeycomb to the double-layer CPCM, the double-layer CPCM exhibited better thermal conductivity and mechanical properties. Moreover, the structure showed better battery temperature control performance, while meeting the temperature control requirements during the charging and discharging cycles of the battery.

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Research on Kelp Coated Packaging Paper

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.200.365 ◽

2012 ◽

Vol 200 ◽

pp. 365-368

Author(s):

Xue Mei Liu ◽

Fun Xin Yang ◽

Feng Xian Wang

Keyword(s):

Tensile Strength ◽

Physical Properties ◽

Food Industry ◽

Coated Paper ◽

Coating Materials ◽

Performance Properties ◽

Coated Papers ◽

Agricultural Produce ◽

Significant Difference ◽

Packaging Paper

Biopolymers have the potential to serve as coating materials for paper to improve its performance properties. The objectives of this study were to determine the effect of kelp coating on the physical properties of coated papers. It was found that kelp coated paper showed significant difference on physical properties, compared with uncoated. Kelp coated papers greatly increased in tensile strength. Paper coated with kelp solution can be used to produce packages with the potential to be used to maintain agricultural produce quality for the food industry, and may have other applications.

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Study on the Mechanical Properties of Bionic Protection and Self-Recovery Structures

Materials ◽

10.3390/ma13020389 ◽

2020 ◽

Vol 13 (2) ◽

pp. 389

Author(s):

Xue Guo ◽

Xinju Dong ◽

Zhenglei Yu ◽

Zhihui Zhang ◽

Xinyu Xie ◽

...

Keyword(s):

Mechanical Properties ◽

Energy Absorption ◽

Double Layer ◽

Layer Structure ◽

Niti Alloy ◽

Impact Resistance ◽

Single Layer ◽

Protective Structure ◽

Bionic Structure ◽

The Impact

A novel protective structure, based on shrimp chela structure and the shape of odontodactylus scyllarus, has been shown to improve impact resistance and energy absorption. A finite element model of NiTi alloy with shape memory was constructed based on the basic principles of structural bionics. The protective structure utilizes NiTi alloy as the matrix, a material with many advantages including excellent compression energy absorption, reusability after unloading, and long life. The mechanical properties of the single-layer model were obtained by static crushing experiments and numerical simulations. Building upon the idea of the monolayer bionic structure design, a two-layer structure is also conceived. Both single-layer and double-layer structures have excellent compression energy absorption and self-recovery capabilities. Compared with the single-layer structure, the double-layer structure showed larger compression deformation and exhibited better energy absorption capacity. These results have important academic and practical significance for improving the impact resistance of protective armor. Our study makes it possible to repair automatic rebounds under the action of pressure load and improves the endurance and material utilization rate of other protective structures.

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FABRICATION OF LSMO SINGLE LAYERS AND LSMO/YBCO DOUBLE LAYERS

International Journal of Nanoscience ◽

10.1142/s0219581x06004711 ◽

2006 ◽

Vol 05 (04n05) ◽

pp. 511-515 ◽

Cited By ~ 1

Author(s):

HONG ZHU ◽

MASANORI OKADA ◽

ATSUSHI KAMIYA ◽

AJAY KRISHNO SARKAR ◽

MASAHITO MATSUI ◽

...

Keyword(s):

Double Layer ◽

Lattice Mismatch ◽

Ion Beam ◽

Single Layer ◽

Epitaxial Films ◽

Double Layers ◽

Ion Beam Sputtering ◽

Beam Sputtering ◽

Substrate Temperatures ◽

Oriented Phase

( La , Sr ) MnO 3 (LSMO) single-layer and LSMO/YBCO double-layer films have been grown on LAO and MgO substrates using ion beam sputtering. For LSMO single-layer films, the highly epitaxial films can be grown at lower substrate temperatures down to 500°C. The epitaxy of the films, which is degraded with increasing TS, can be restored by supply of plasma oxygen. Smaller lattice mismatch of LSMO on LAO gives two-dimensional step-and-terrace type growth, whereas on MgO grain type growth is observed due to larger mismatch. For the double-layer films, LSMO layer can be grown epitaxially on a-oriented YBCO underlayer, but a part of the underlying a-YBCO is changed into c-YBCO during the deposition of overlayer. For c-YBCO underlayer, a part of the underlying c-YBCO is changed into (110)-oriented phase after the deposition of overlayer. Then it is necessary to deposit the overlayer at lower temperatures.

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Economics of coated paper production made from deinked pulp

TAPPI Journal ◽

10.32964/tj12.4.19 ◽

2013 ◽

Vol 12 (4) ◽

pp. 19-27

Author(s):

PATRICK HUBER ◽

LAURENT LYANNAZ ◽

BRUNO CARRÉ

Keyword(s):

Mechanical Properties ◽

Optimization Methods ◽

Coating Process ◽

Coated Paper ◽

Paper Production ◽

Base Paper

The fraction of deinked pulp for coated paper production is continually increasing, with some mills using 100% deinked pulp for the base paper. The brightness of the coated paper made from deinked pulp may be reached through a combination of more or less extensive deinking, compensated by appropriate coating, to optimize costs overall. The authors proposed general optimization methods combined with Kubelka-Munk multilayer calculations to find the most economical combination of deinking and coating process that would produce a coated paper made from DIP, at a given target brightness, while maintaining mechanical properties.

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Discrete element method to model cracking for two layer systems

TAPPI Journal ◽

10.32964/tj18.2.101 ◽

2019 ◽

Vol 18 (2) ◽

pp. 101-108

Author(s):

Daniel Varney ◽

Douglas Bousfield

Keyword(s):

Discrete Element Method ◽

Flexural Modulus ◽

Single Layer ◽

Discrete Element ◽

Flexural Stress ◽

Layer System ◽

Three Point Bending ◽

Moving Force ◽

Coating Layers ◽

Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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