Effects of coating formulation on coating thermal properties and coated paper print quality in xerography

2012 ◽  
Vol 27 (2) ◽  
pp. 451-458 ◽  
Author(s):  
Ning Yan ◽  
Chong Liang ◽  
David Vidal ◽  
Xuejun Zou
Keyword(s):  
Thermal Conductivity ◽  
Geometric Mean ◽  
Thermal Characteristics ◽  
Print Quality ◽  
Coated Papers ◽  
Coating Layers ◽  
Visual Ranking ◽  
Coating Formulation ◽  
Styrene Butadiene ◽  
Bulk Thermal Conductivity

Abstract The effects of coating formulation on thermal characteristics of coating layers (namely thermal diffusivity, specific heat capacity and heat conductivity) were systematically studied and their impact on xerography print quality was evaluated. Model coatings were prepared using ground calcium carbonate or kaolin pigment mixed with styrene butadiene latex binder in various proportions (from 6 to 25 pph). As expected, porosity was shown to be a key parameter for thermal conductivity of the coating layers, and is mainly determined by the latex concentration. Particle size distribution (PSD) and pigment morphology also affected the thermal characteristics of the coating layers. It was found that the bulk thermal conductivity of the coating layers can be accurately predicted by a geometric mean model based on the pigment, latex and air contents. Print quality on model coated papers was evaluated in terms of print gloss, toner adhesion and pairwise visual ranking. It was demonstrated that print gloss is improved by decreasing the bulk thermal conductivity of the coatings. The coating formulated with the pigments with the steepest PSD and 10 pph of latex had a relatively low thermal conductivity and the best print quality.

scholarly journals O przewodności cieplnej meteorytu Jezersko

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (1) ◽  
pp. 10-19
Author(s):  
Marian A. Szurgot ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Geometric Mean ◽  
Mean Value ◽  
Air Pressure ◽  
Ordinary Chondrites ◽  
K Value ◽  
The Mean ◽  
Predicted Values ◽  
Bulk Thermal Conductivity

The thermal conductivity (K) of Jezersko H4 meteorite was predicted by various models of rocks, using literature data on the chemical composition, porosity (P), and by relationships between thermal conductivity and porosity, and between thermal conductivity and thermal diffusivity (D). The results confirm that the porosity of the chondrite and air pressure significantly affect thermal conductivity. The thermal conductivity of the chondrite skeleton/matrix predicted by the modal composition of the meteorite and by the geometric mean model is equal to 4.35 W m−1 K−1, and by arithmetic and harmonic mean models: 4.9 W m−1 K−1at 300 K. Bulk thermal conductivity of the meteorite predicted by the geometric mean model is equal to 2.6 W m-1 K-1 for air pressure of 1 atm, and 1.0 W m−1 K−1in vacuum at 300 K. The Hashin–Shtrikman model predicts the values: 2.4 and 1.9 W m−1 K−1, the Clausius–Mossotti model: 2.2 and 1.9 W m-1 K-1, and the mean of two-layer models: 2.1 and 2.0 W m−1 K−1 at 300 K, for air pressure of 1 atm, and in vacuum, respectively. The relationships between thermal conductivity and porosity based on experimental data for ordinary chondrites indicate a mean K value for bulk thermal conductivity of the Jezersko meteorite in vacuum: 1.18 W m−1 K−1, and between thermal conductivity and thermal diffusivity the mean value: 1.12 W m−1 K−1at 200–300 K. The mean value for all predictions for bulk thermal conductivity of the meteorite for air at 1 atm is equal to 2.45 ± 0.30 W m−1 K−1 (range: 2.0–2.9 W m−1 K−1) at 300 K, and in vacuum: 1.40 ± 0.40 W m−1 K−1 (range: 0.95–2.0 W m−1 K−1) at 200–300 K. Predicted values of bulk thermal conductivity of the Jezersko meteorite, for air and in vacuum, are in the range of values recently reported by Soini et al. (2020) for the H4 group of chondrites: 2.8 ± 0.6 W m−1 K−1, mean K for air at 1 atm, and 1.9 ± 1.0 W m−1 K−1 mean K value in vacuum at 200–300 K.

Flexographic ink-coating interactions: effects of latex variations in coating layers

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 253-262 ◽  
Author(s):  
ERIK BOHLIN ◽  
CAISA JOHANNSON ◽  
MAGNUS LESTELIUS
Keyword(s):  
Contact Angles ◽  
High Ratio ◽  
Print Quality ◽  
Particle Sizes ◽  
Mixed Composition ◽  
Coating Surface ◽  
Covered Area ◽  
Surface Optical ◽  
Flexographic Printing ◽  
Coating Formulation

The effect of coating structure variations on flexographic print quality was studied using pilot-coated paperboard samples with different latex content and latex particle sizes. Two latexes, with particle sizes of 120 nm and 160 nm, were added at either 12 parts per hundred (pph) or 18 pph to the coating formulation. The samples were printed with full tone areas at print forces of 25 N and 50 N in a laboratory flexographic printing press using a waterbased ink. A high ratio of uncovered areas (UCAs) could be detected for the samples that contained 18 pph latex printed at a print force of 25 N. UCAs decreased with increased print force and with decreased amounts of latex in the coating formulation. The fraction of latex covered area on the coating surface was estimated to be 0.35–0.40 for the 12 pph, and 0.70–0.75 for the 18 pph samples. The ink penetration depth into the coating layer could be linked to the fraction of latex-free areas on the coating surface. Optical cross section microscopy indicated that a higher printing force did not increase the depth of penetrated ink to any greater extent. Higher printing force did increase contact between plate and substrate, leading to an improved distribution of the ink. This, in turn, increased print density and decreased UCAs. On closer inspection, the UCAs could be categorized as being induced by steep topographic changes. When appearing at other locations, they were more likely to be caused by poor wetting of the surface. To understand the wetting behavior of the coating surface, observed contact angles were compared with calculated contact angles on surfaces of mixed composition.

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

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

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.

Evaluation of compression-recovery and thermal characteristics of multilayer bedding textiles

2020 ◽  
Vol 32 (5) ◽  
pp. 631-643
Author(s):  
Sedat Özer ◽  
Yaşar Erayman Yüksel ◽  
Yasemin Korkmaz
Keyword(s):  
Thermal Conductivity ◽  
Sleep Quality ◽  
Thermal Comfort ◽  
Sleep Duration ◽  
Human Body ◽  
Design Methodology ◽  
Thermal Characteristics ◽  
Air Permeability ◽  
Content Type ◽  
Thermal Comfort Properties

PurposeDesign of bedding textiles that contact the human body affects the sleep quality. Bedding textiles contribute to comfort sense during the sleep duration, in addition to ambient and bed microclimate. The purpose of this study is to evaluate the effects of different layer properties on the compression recovery and thermal characteristics of multilayer bedding textiles.Design/methodology/approachIn this study, woven and knitted multilayer bedding textiles were manufactured from fabric, fiber, sponge and interlining, respectively. Different sponge thickness, fiber and interlining weight were used in the layers of samples. Later, the pilling resistance, compression and recovery, air permeability and thermal conductivity of multilayer bedding textiles were investigated.FindingsThe results indicated that samples with the higher layer weight and thickness provide better compression recovery and lower air permeability properties. It was also found that knitted surfaces show the higher air permeability than the woven surfaces depending on the fabric porosity. Layer properties have insignificant effect on the thermal conductivity values.Originality/valueWhile researchers mostly focus on thermal comfort properties of garments, there are limited studies about comfort properties of bedding textiles in the literature. Furthermore, compression recovery properties of bedding textiles have also a great importance in terms of comfort. Originality of this study is that these properties were analyzed together.

Characterizing Bulk Thermal Conductivity and Interface Contact Resistance Effects of Thermal Interface Materials in Electronic Cooling Applications

2003 ◽  
Author(s):  
Vadim Gektin ◽  
Sai Ankireddi ◽  
Jim Jones ◽  
Stan Pecavar ◽  
Paul Hundt
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Thermal Performance ◽  
Electronic Cooling ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Contact ◽  
Interface Materials ◽  
Bulk Thermal Conductivity

Thermal Interface Materials (TIMs) are used as thermally conducting media to carry away the heat dissipated by an energy source (e.g. active circuitry on a silicon die). Thermal properties of these interface materials, specified on vendor datasheets, are obtained under conditions that rarely, if at all, represent real life environment. As such, they do not accurately portray the material thermal performance during a field operation. Furthermore, a thermal engineer has no a priori knowledge of how large, in addition to the bulk thermal resistance, the interface contact resistances are, and, hence, how much each influences the cooling strategy. In view of these issues, there exists a need for these materials/interfaces to be characterized experimentally through a series of controlled tests before starting on a thermal design. In this study we present one such characterization for a candidate thermal interface material used in an electronic cooling application. In a controlled test environment, package junction-to-case, Rjc, resistance measurements were obtained for various bondline thicknesses (BLTs) of an interface material over a range of die sizes. These measurements were then curve-fitted to obtain numerical models for the measured thermal resistance for a given die size. Based on the BLT and the associated thermal resistance, the bulk thermal conductivity of the TIM and the interface contact resistance were determined, using the approach described in the paper. The results of this study permit sensitivity analyses of BLT and its effect on thermal performance for future applications, and provide the ability to extrapolate the results obtained for the given die size to a different die size. The suggested methodology presents a readily adaptable approach for the characterization of TIMs and interface/contact resistances in the industry.

scholarly journals Thermal conductivity of sandstones from Biot’s coefficient

Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. D173-D185 ◽  
Author(s):  
Tobias Orlander ◽  
Eirini Adamopoulou ◽  
Janus Jerver Asmussen ◽  
Adam Andrzej Marczyński ◽  
Harald Milsch ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flow ◽  
Cross Section ◽  
Geometric Mean ◽  
Well Log ◽  
Biot’S Coefficient ◽  
Model Predictions ◽  
The Cross ◽  
Rock Texture

Thermal conductivity of rocks is typically measured on core samples and cannot be directly measured from logs. We have developed a method to estimate thermal conductivity from logging data, where the key parameter is rock elasticity. This will be relevant for the subsurface industry. Present models for thermal conductivity are typically based primarily on porosity and are limited by inherent constraints and inadequate characterization of the rock texture and can therefore be inaccurate. Provided known or estimated mineralogy, we have developed a theoretical model for prediction of thermal conductivity with application to sandstones. Input parameters are derived from standard logging campaigns through conventional log interpretation. The model is formulated from a simplified rock cube enclosed in a unit volume, where a 1D heat flow passes through constituents in three parallel heat paths: solid, fluid, and solid-fluid in series. The cross section of each path perpendicular to the heat flow represents the rock texture: (1) The cross section with heat transfer through the solid alone is limited by grain contacts, and it is equal to the area governing the material stiffness and quantified through Biot’s coefficient. (2) The cross section with heat transfer through the fluid alone is equal to the area governing fluid flow in the same direction and quantified by a factor analogous to Kozeny’s factor for permeability. (3) The residual cross section involves the residual constituents in the solid-fluid heat path. By using laboratory data for outcrop sandstones and well-log data from a Triassic sandstone formation in Denmark, we compared measured thermal conductivity with our model predictions as well as to the more conventional porosity-based geometric mean. For outcrop material, we find good agreement with model predictions from our work and with the geometric mean, whereas when using well-log data, our model predictions indicate better agreement.

scholarly journals Thermal Analysis of AlGaN/GaN HEMTs Considering Anisotropic And Inhomogeneous Thermal Conductivity

2021 ◽  
Author(s):  
Yao Li ◽  
Zixuan Zheng ◽  
Qun Li ◽  
Hongbin Pu
Keyword(s):  
Thermal Conductivity ◽  
Temperature Rise ◽  
Power Dissipation ◽  
Thermal Characteristics ◽  
Maximum Temperature ◽  
Base Temperature ◽  
Initial Growth ◽  
Boltzmann Transport ◽  
Growth Interface ◽  
Anisotropic Thermal Conductivity

Abstract To examine the differences of thermal characteristics introduced by material thermal conductivity, anisotropic polycrystalline diamond (PCD) and GaN are analyzed based on the accurate model of grain sizes in the directions of parallel and vertical to the interface and an approximate solution of the phonon Boltzmann transport equation. Due to the space-variant grain structures of PCD, the inhomogeneous-anisotropic local thermal conductivity, homogeneous-anisotropic thermal conductivity averaged over the whole layer and the typical values of inhomogeneous-isotropic thermal conductivity are compared with/without anisotropic GaN thermal conductivity. The results show that the considerations of inhomogeneous-anisotropic PCD thermal conductivity and anisotropic GaN thermal conductivity are necessary for the accurate prediction of temperature rise in the GaN HEMT devices, and when ignoring both, the maximum temperature rise is undervalued by over 16 K for thermal boundary resistance (TBR) of 6.5 to 60 m2K/GW at power dissipation of 10 W/mm. Then the dependences of channel temperature on several parameters are discussed and the relations of thermal resistance with power dissipation are extracted at different base temperature. Compared with GaN, SiC and Si substrates, PCD is the most effective heat spreading layer though limited by the grain size at initial growth interface.

Thermal conductivity of styrene butadiene rubber compounds with natural rubber prophylactics waste as filler

1999 ◽  
Vol 35 (9) ◽  
pp. 1687-1693 ◽  
Author(s):  
N.S. Saxena ◽  
P. Pradeep ◽  
G. Mathew ◽  
S. Thomas ◽  
M. Gustafsson ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Natural Rubber ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Rubber Compounds ◽  
Styrene Butadiene

Impact of non-uniform water absorption on water-interference print mottle in offset printing

2018 ◽  
Vol 33 (1) ◽  
pp. 150-163 ◽  
Author(s):  
Sofia Thorman ◽  
Göran Ström ◽  
Patrick A. C. Gane
Keyword(s):  
Moisture Absorption ◽  
Staining Technique ◽  
Relevant Information ◽  
Print Quality ◽  
Surface Adhesion ◽  
Offset Printing ◽  
Surface Moisture ◽  
Coated Papers ◽  
Burn Out ◽  
Lift Off

Abstract Print mottle is a serious and yet common print defect in offset printing. An imbalance between the feed of fountain solution and the ability of the paper substrate to absorb and transport this water away from the surface can cause moisture/water interference problems. In the study presented here, we have investigated the uniformity of aqueous absorption and coating structure of pilot-coated papers with different types and dosages of dispersants and linked this to print mottle and uncovered areas (UCA). In earlier studies, the print quality of these papers indicated that a moderate addition of excess dispersant caused ink refusal, ink-lift-off (ink-surface adhesion failure) and water-interference mottle when printing at elevated fountain feed. In the present study, we have shown that a majority of the samples with uneven water/moisture absorption and an uneven burn-out reflectance tended to have more severe printing problems related to surface-moisture/water.An aqueous staining technique was used to characterise the absorption non-uniformities. This method has been developed previously with focus on absorption of flexographic water-based inks but can clearly give relevant information also for offset printing, when it comes to moisture/water interference mottle.

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