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Article
Publication date: 1 December 2004

73

Abstract

Details

Pigment & Resin Technology, vol. 33 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 9 January 2009

R.D. Sudduth

In part I of this study a new dry coating analysis was developed relating pigment cluster voids and pigment particle distribution to the pigment cluster dispersion…

Abstract

Purpose

In part I of this study a new dry coating analysis was developed relating pigment cluster voids and pigment particle distribution to the pigment cluster dispersion coefficient, Cq, and the critical pigment volume concentration (CPVC). Part II of this study has addressed a wet coating analysis to relate pigment particle size distribution and viscosity in a coating formulation to the pigment cluster dispersion coefficient.

Design/methodology/approach

This study introduced the relationships for the wet coating by building on the dry coating evaluations introduced in part I of this study. Part II of this study showed that the CPVC for a solvent based coating can be significantly influenced by a change in the viscosity measured interaction coefficient, σ, as influenced by a change in an additive such as the surfactant concentration in the matrix or polymer phase of the coating. The CPVC was also shown to be strongly influenced by a separate analysis of the pigment particle size distribution to modify the coating viscosity.

Findings

It was pointed out recently that an increase in flow additive increased the CPVC but decreased viscosity. Consequently, it was shown theoretically in this study that viscosities compared at the same relative viscosity, η/η0, and at the same filler composition, fi, using the generalized viscosity model would require decrease in the interaction coefficient, σ, to increase the global volume fraction of filler or pigment, ΦF. This implied that a measurement of the interaction coefficient, σ, should be a direct measure of the ability of the CPVC to be modified. A minimum viscosity from the generalised viscosity model also resulted at the maximum packing fraction, which in turn was found to increase the CPVC of the coating. Consequently, part II of this study has yielded a useful relationship between the cluster dispersion coefficient, Cq, and the interaction coefficient, σ, from the generalised viscosity model.

Research limitations/implications

While the experimental measurement of the parameters to isolate the clustering concepts introduced in this study may be difficult, it is expected that better quantitative measurement of clustering concepts will eventually prove to be very beneficial to providing improved suspension applications including coatings. The close relationship introduced in this study between clustering concepts and viscosity should provide an improved ability to measure the parameters to isolate clustering in coatings and other suspension applications.

Practical implications

The theoretical relationship developed in this study between the pigment cluster dispersion coefficient, Cq, and CPVC and the theoretical and experimental relationship between CPVC and the viscosity interaction coefficient, σ, inferred a direct relationship between Cq and the viscosity interaction coefficient, σ. Consequently, it was shown that the theoretical pigment cluster model developed in this study could be directly related to the experimental matrix additive composition controlling viscosity in a coating formulation. The practical implication is that the measurement tools introduced in this study should significantly influence future suspension formulations to provide better measurement and control of clustering and viscosity in coatings and other suspension applications.

Originality/value

Part II of this study has shown how a useful relationship can be generated between the interaction coefficient, σ, from the generalised viscosity model and the pigment cluster dispersion coefficient, Cq, developed in part I of this study. In addition, this study also showed that effective control of the CPVC of a coating can be modified by judicious control of the interaction coefficient using pigment particle size distribution and/or viscosity control additives in a wet coating analysis.

Details

Pigment & Resin Technology, vol. 38 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 22 May 2009

Qiao Yang, Xiao H. Yang, Pan Wang, Wei L. Zhu and Xiao Y. Chen

The purpose of this paper is to measure the apparent and complex viscosities of the zinc‐rich coatings derived from sodium silicate solution modified with aluminium…

Abstract

Purpose

The purpose of this paper is to measure the apparent and complex viscosities of the zinc‐rich coatings derived from sodium silicate solution modified with aluminium chloride (AlCl3), and then theoretically analyse the relation between viscosity behaviour and physiochemical mechanisms.

Design/methodology/approach

According to the different dosages of AlCl3, five coatings were prepared. The apparent viscosities as functions of shear rate, time and temperature, complex viscosity with variations of temperature and heating rate of these coatings were measured using an AR500 rheometer.

Findings

Results showed that the zinc‐rich coatings possessed the typical shear thinning behaviour and the apparent viscosity increased with time until solidification. Complex results showed that the complex viscosity depended strongly on heating rate. Both apparent and complex viscosities initially decreased to minimum and then started to increase, while temperature was ramped from 0 to 70°C.

Originality/value

It is believed that there is no published literature about the apparent and complex viscosities of the zinc‐rich coatings from sodium silicate solution modified with AlCl3. This paper presents the first attempt to obtain the rheological data of these zinc‐rich coatings.

Details

Pigment & Resin Technology, vol. 38 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 March 1989

Manfred Hoppe

A disadvantage found when conventional weather resistant powder coatings are compared to liquid coatings is their relatively poor flow properties. The flow of thermoset…

Abstract

A disadvantage found when conventional weather resistant powder coatings are compared to liquid coatings is their relatively poor flow properties. The flow of thermoset powder coatings depends on a number of factors, including the selection of suitable pigments and fillers, pigment concentration, additives such as flow agents, bake schedule, reactivity and structure of the resinous components, melt viscosity, and the viscosity profile during crosslinking. This paper reports about recently developed carboxyl terminated triglycidyl isocyanurate (TGIC) cured polyesters which result in powder coatings with remarkably improved flow properties due to the polyester's molecular structure and functionality and the viscosity profile during the curing process. These improvements have been reached without any prolongation of the gel time and without compromising the weathering resistance of the film. Such new powder coatings completely crosslink at 160°C within 15 minutes yielding films with excellent mechanical properties.

Details

Pigment & Resin Technology, vol. 18 no. 3
Type: Research Article
ISSN: 0369-9420

Article
Publication date: 1 January 1985

N.V.K. Dutt and D.H.L. Prasad

Paints (surface coatings), primarily used to protect various substrates from the corroding action of acidic and alkaline substances, largely contain polymers as coating

Abstract

Paints (surface coatings), primarily used to protect various substrates from the corroding action of acidic and alkaline substances, largely contain polymers as coating formulations. Examples of generally used polymers are: butadiene based (space), epoxy resins and silicone fluids (concrete vinyl polymers and polyurethanes (optical fibres) alkyds and acrylics (electronics) and polyester resins (wood, metal and fibre‐glass reinforcements). The binder‐pigment interaction controls important properties like hardness, flexibility, permeability, adhesion, gloss, and mechanical properties and contributes finally to the success or otherwise of the paint as a protective surface‐coating. Excellence of pigment dispersion and paint performance are thus intimately related.

Details

Pigment & Resin Technology, vol. 14 no. 1
Type: Research Article
ISSN: 0369-9420

Article
Publication date: 16 August 2021

Bifeng Yin, Xuefeng Wang, Bo Xu, Gongyin Huang and Xin Kuang

The purpose of this paper was to improve the frictional wear resistance properties of piston skirts caused by the low viscosity lubricant by studying the tribological…

Abstract

Purpose

The purpose of this paper was to improve the frictional wear resistance properties of piston skirts caused by the low viscosity lubricant by studying the tribological performance of three novel coating materials.

Design/methodology/approach

Comparative tribological examinations were performed in a tribological tester using the ring-block arrangement under two viscosity lubricants, the loading force was applied as 100 N, the speed was set to 60 r/min and the testing time was 180 min.

Findings

Under low viscosity lubricant, the friction coefficient and wear of the three coatings all increase, and the friction coefficient and wear of the PTFE coating are the largest, while the MoS2 coating has the lowest friction coefficient and wear. Under low viscosity lubricant, the friction coefficient of the MoS2 coating is 2.1%–5.4% and 20.0%–24.3% lower than that of the SiO2 and PTFE coating, respectively. The friction coefficient and wear fluctuation rate of the MoS2 coating is the smallest when the lubricant viscosity decreases, which indicates that the MoS2 coating has excellent stability and adaptability under low viscosity lubricant.

Originality/value

To reduce the piston skirt wear caused by low viscosity lubricant in heavy-duty diesel engines, the friction and wear adaptability of three novel composite coating materials for piston skirts were compared under 0 W-20 low viscosity lubricant, which could provide a guidance for the application of wear-resistant materials for heavy-duty diesel engine piston skirt.

Details

Industrial Lubrication and Tribology, vol. 73 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 December 1985

J Boxall

The rheological properties of a coating are important determinants of storage, application and flow characteristics and, as such, the need for its accurate measurement is…

Abstract

The rheological properties of a coating are important determinants of storage, application and flow characteristics and, as such, the need for its accurate measurement is an important requirement in formulation development. Measurement of rheology is also an important phase of quality control testing, though frequently less sophisticated, more rapid, characterisation techniques may sometimes be used here. This article will consider some of the literature concerned with techniques of measuring coating rheology.

Details

Pigment & Resin Technology, vol. 14 no. 12
Type: Research Article
ISSN: 0369-9420

Article
Publication date: 1 September 1996

G. Zak, A.Y.F. Chan, C.B. Park and B. Benhabib

Refers to how the mechanical properties of polymer‐based composite objects produced via rapid layered fabrication methods can be improved significantly using short…

1573

Abstract

Refers to how the mechanical properties of polymer‐based composite objects produced via rapid layered fabrication methods can be improved significantly using short discontinuous fibres as reinforcements. Notes in this context, that the viscosity of the uncured fibre‐photopolymer composite liquids affects the raw‐material handling, the layer formation and the draining operations. Assesses the effects of aspect ratio, surface coating and volume fraction of short glass fibres on the viscosity of the fibre‐photopolymer composite liquids. Based on extensive experimentation and analysis, concludes that the shear viscosity of the composite liquids increases with increasing fibre‐volume fraction, showing that this effect is more pronounced at low shear rates than at high shear rates. Reveals, similarly, that the aspect ratio of the dispersed fibres has a stronger effect on the increase of viscosity at low shear rates and that the surface coating of the dispersed fibres also affects the viscosity of the composite liquids.

Details

Rapid Prototyping Journal, vol. 2 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 January 1994

Reducing Level of Alcohol in Inks ‐ A medium‐sized US ink manufacturer recently needed to reduce the level of alcohol in its bases for water‐based inks. Ciba Geigy…

Abstract

Reducing Level of Alcohol in Inks ‐ A medium‐sized US ink manufacturer recently needed to reduce the level of alcohol in its bases for water‐based inks. Ciba Geigy Pigments Division's Inks Technical Centre developed an improved formulation, containing half the alcohol of the previous one and 40 per cent more pigment to allow the ink producer to meet VOC limits and increase production efficiency, at no additional cost.

Details

Pigment & Resin Technology, vol. 23 no. 1
Type: Research Article
ISSN: 0369-9420

Article
Publication date: 1 October 1979

Americus

Behind every successful technology is a great body of scientific knowledge. The paint industry managed to get along pretty well from the time of the Egyptians until World…

Abstract

Behind every successful technology is a great body of scientific knowledge. The paint industry managed to get along pretty well from the time of the Egyptians until World War I, a span of approximately 5,000 years, without much scientific insight. Indeed, the empirical approach to paint formulation could hardly be criticised. When one visits museums of Egyptology today, one sees coatings formulated three to five thousand years ago which are bright coloured and which still have good adhesion and film integrity. But coating mummy cases in a very dry climate is considerably less demanding than coating missiles which find themselves in a hostile environment. Although paint for mummy cases, houses, and barns and even the first assembly‐line‐produced automobiles could be made without much scientific understanding, it is fair to say that coatings for the exacting demands of modern technology could never have evolved without an understanding of the scientific principles on which the modern coatings industry is based. The scientific basis for the modern coatings industry is found in an understanding of polymer chemistry, an understanding of the chemistry of solvents, a knowledge of the chemistry of pigments, and a large body of physical chemistry relating to solubility, rheology, adhesion, cohesion, and many other important phenomena.

Details

Pigment & Resin Technology, vol. 8 no. 10
Type: Research Article
ISSN: 0369-9420

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