Catalytically Active Additives

Bieleman, Johan H.; Lomölder, R.

doi:10.1002/9783527613304.ch7

Cited by 8 publications

(15 citation statements)

References 4 publications

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“…[50] Cellulosic and associative thickeners are the two primary categories of thickeners. [17,51,52] The mechanism of action for cellulosic thickeners is the development of three-dimensional network structures through physical interactions between thickening molecules and dispersive medium. [53] For the associative thickeners, intra-or intermolecular linkages are created between the hydrophobic groups on their molecules and other hydrophobic species in the formulation, including those found on the surface of the particles.…”

Section: Rheological Properties Of Wpu Incorporating Thickenersmentioning

confidence: 99%

Structure‐property relationships of waterborne polyurethane (WPU) in aqueous formulations

Patti

Acierno²

2023

Vinyl Additive Technology

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This study provides an overview of the rheological properties of aqueous polyurethanes (WPU), as the main component, or as a thickening additive in aqueous formulations. Waterborne polyurethanes (WPU) have been proposed as an environmentally friendly alternative to conventional solvent-based solutions in a variety of industrial applications such as coatings, adhesives, inks. In all these fields, the control of rheological properties became an important prerogative to determine the quality of the dispersion and its potential applicability. First, the effect of parameters such as components, particle size and content, temperature, and interactions on dispersion viscosity was reported. Then, the effect of two additives, i.e. thickeners and nanomaterials, on structure-property relationships of WPU-base systems, was described. Thickeners are rheological modifiers, commonly used to stabilize the dispersion and prevent flocculation and sedimentation of the particles, or to change the flow behavior of dispersions from Newtonian to pseudoplastic. These species can interact with water and polymer particles to create a network structure that alters the flow resistance, and thus viscosity. The use of hyperbranched aqueous polyurethane as thickening agent in WPU formulations was also presented. On the other hand, nanostructured fillers (0D/1D/2D) or a combination thereof in waterborne polyurethane led to the formation of specific microstructures that prevented the penetration of water, oxygen, and corrosive substances, also improved mechanical and thermal properties, allowing the development of high-performance WPU-based products.nanomaterials, rheological properties, thickeners, waterborne polyurethane dispersions | INTRODUCTIONPolyurethane (PU) has attracted scientific and industrial attention, due to the versatility of pristine constituents, [1] that allowed an adaptable behavior for a large variety of requirements and customized products (i.e. foams, [2] composites, [3] coatings and adhesives, [4] inks, [5] etc.). This polymer is commonly used in advanced coating technology given improvements in the quality, appearance, and lifespan of treated substrates. Traditionally, polyurethane formulations are made from harmful organic solvents, such as toluene, xylene, formaldehyde. During the

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Section: Rheological Properties Of Wpu Incorporating Thickenersmentioning

confidence: 99%

Structure‐property relationships of waterborne polyurethane (WPU) in aqueous formulations

Patti

Acierno²

2023

Vinyl Additive Technology

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“…They do influence not only the drying time, through drying and film hardness, but also can reduce formation of skin and paint defects, improve the coating gloss, durability, color retention, pigment-wetting properties, and performance at low temperatures and a high air humidity. 240 Such a performance is attributed to many working mechanisms (e.g., cocatalysis due to Lewis acidic properties, improved oxygen uptake, cross-linking through carboxylic group coordination, deceleration of autoxidation on the surface leading to a better through drying, and adsorption on the pigment particle whichc may deactivate the primary driers), but only a few of them are supported by hard experimental data. 31,242,243 A recent investigation compared the performance of popular drier combinations Co/Zr, Co/Ca, and Co/Zr/Ca and with similar systems containing manganese and iron-based primary driers.…”

Section: ■ Secondary Driersmentioning

confidence: 99%

“…Fine-tuning of the autoxidation process is usually not done by strong antioxidants or oxygen scavengers but by metal carboxylates soluble in organic solvents known as secondary driers. Such compounds are not catalytically active themselves but can improve the performance of primary driers. , It should be noted that secondary driers are often sorted on “through driers” and “auxiliary driers”, but this classification is not recommended, as the mechanism of their action is not fully understood on the molecular level and could be very different among each group . Commonly used secondary driers include 2-ethylhexanoates of lithium, potassium, calcium, strontium, zirconium, zinc, aluminum, and bismuth.…”

Section: Secondary Driersmentioning

confidence: 99%

Curing of Air-Drying Paints: A Critical Review

Honzı́ček

2019

Ind. Eng. Chem. Res.

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This review article provides a comprehensive overview of curing processes relevant to air-drying paints. It is focused not only on binders derived from plant oils but also on oriental lacquers and their synthetic congeners as their solidification and hardening processes are driven by chemical reactions with air-oxygen. The main aim of this article is to bring a critical look on this subject omitting deep-seated misinterpretation and oversimplification often appearing in the field of paint technology. Such objective was achieved by utilization of the latest knowledge appearing in various areas of chemical research, e.g. organic chemistry, biochemistry, physical chemistry, computational chemistry and inorganic chemistry.

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“…In case of the waterborne systems, the desired spreading performance during application is adjusted by additions of rheological modifiers, 2 which typically, constitute up to 5% of the overall product formulation. Most common thickeners used in paints are functionalized additives, based hydroxyethyl cellulose, alkali‐soluble emulsion, or ethoxylated urethanes 3 . Due to the structural and functional versatility of the hydrophobically modified ethoxylated urethanes (HEURs), they are currently most in‐demand specialty paint additives in terms of production volume 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Most common thickeners used in paints are functionalized additives, based hydroxyethyl cellulose, alkali-soluble emulsion, or ethoxylated urethanes. 3 Due to the structural and functional versatility of the hydrophobically modified ethoxylated urethanes (HEURs), they are currently most indemand specialty paint additives in terms of production volume. 4 To produce these HEURs, an oligomeric diol, here poly(ethylene glycol) (PEG), is reacted with a diisocyanate (ISO) to generate a viscous hydrophilic backbone.…”

Section: Introductionmentioning

confidence: 99%

Optimal design and operation of reactive extrusion processes: Application to the production and scale‐up of polyurethane rheology modifiers for paints

Cegla,

Fage,

Kemmerling

et al. 2023

Polymer Engineering & Sci

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In this work, the methodology for the optimal design, operation and scale‐up of reactive extrusion processes in twin‐screw extruders previously presented in Reference (Cegla and Engell, 2023). is applied to the production of hydrophobically ethoxylated urethanes (HEURs). The new process is a promising alternative to the current batch technology in large reactors with long residence times. We demonstrate the use of model‐based design and scale‐up for this case. A novel mechanistic finite volume twin‐screw extruder model is used as the process model, which is adapted to the process at hand by embedding a detailed description of the HEUR chemistry and rheology. An economic cost function is used to examine the scale‐up process from an 18 mm extruder to a 27 and 75 mm extruders, considering a selected range of products. The comparison between the optimization results obtained for the individual products with the optimization results for the production of multiple material grades using the same screw setup shows the high flexibility of the extruder‐based process. Significant energy savings compared with the conventional batch process can be achieved using reactive extrusion. To quantify the effort for the transition to a purely continuous production in terms of flexibility and process logistics, product changeovers are investigated.Highlights Intensification of the HEUR production by reactive extrusion. Detailed model for the twin‐screw extruder and the chemistry. Optimization of extruder, screw design, and operating conditions. Model‐based scale‐up from laboratory to industrial scale. Investigation of flexible industrial production of different HEURs.

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Catalytically Active Additives

Cited by 8 publications

References 4 publications

Structure‐property relationships of waterborne polyurethane (WPU) in aqueous formulations

Structure‐property relationships of waterborne polyurethane (WPU) in aqueous formulations

Curing of Air-Drying Paints: A Critical Review

Optimal design and operation of reactive extrusion processes: Application to the production and scale‐up of polyurethane rheology modifiers for paints

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