Lacquer Coatings Research Articles

Electron-beam curing of lacquer coatings. Part II. Lacquer binders based on unsaturated polyester resins and acrylated epox yresins

Electron-beam curing of lacquer coatings. Part II. Lacquer binders based on unsaturated polyester resins and acrylated epox yresins

Evaluating the condition of paint and lacquer coatings by a method of measuring the impedance in cyclic tests of samples

.Tthe samples were prepared from panels of AMg61 aluminum alloy, a basic ship hull material, and painted by different methods. The edges of the samples (gauge length 4  20  90 ram) were rounded for the purpose of reducing the spread in experimental data since as a rule failure of a paint or lacquer coating starts at sharp edges. Therefore the cross section of the samples in the gauge length tended to approach an elliptical shape. in measuring the impedance the samples were placed in a special cylindrical cell of VT-I titanium alloy filled with a 3% sodium chloride solution. Its housing simultaneously played the role of the auxiliar electrode. The sample was fastened in the end walls of the cell with the use of rubber seals. To decrease the housing of the latter in the area of the water line was coated on the exterior with an oxide film created by thermal oxidation and possessing a hlghelectrical resistance. The impedance measurements were made with an R-568 ac bridge with a frequency of 510 Hz and an ac voltage of not more than 8 mV at room temperature. The ac voltage was provided by a G3-33 pulse generator and measured with a V3-13 voltmeter. The cell with the sample was connected to the bridge with clamps possessing the minimum induction. During development of the method empirical relationships were obtained of the change in resistance and capacitance of the electrochemical cell with the sample to the area of damage of the paint or lacquer coating. To obtain them successive increasing in area damage of a paint coating applied to the previously etched surface of a sample from a panel of AMg61 alloy with one layer of VL02 primer and four layers of KhS720S paint was accomplished. After each new damage inspected for area the resistance and capacitance of the cell with the sample was measured.

Electron-beam curing of lacquer coatings. Part I. Introduction and literature review

Electron-beam curing of lacquer coatings. Part I. Introduction and literature review

応力塗料膜のき裂特性に関する研究（負荷時間の影響）

Since brittle lacquer coating of air-drying type displays viscoelastic behaviour, brittleness of the lacquer coating is markedly dominated by loading time and test temperature. When the technique of brittle coating is applied in the strain measurement, it is necessary to compare the coating cracks on the calibration bars with those on the engineering structures to be inspected, although these two type of specimens have been subjected to different load application time. Besides, the relaxation method is often utilized to analyze the compressed regions on the structure.Few studies have been made on the mechanical properties of the coating by taking viscoelasticity into account, because it is too difficult to make mechanical tests on a coating film of high brittleness separately. In this study, therefore, the influence of both loading time and test temperature on the strain sensitivity of some brittle lacquer coatings were investigated on the calibration bars by using a new loading device controlling the load application time.The results obtained are as follows.The influence of loading and relaxation time on the strain sensitivity was clarified at various test temperatures. It was confirmed that the strain sensitivity scarcely changed with time up to about 10 seconds. The sensitivity master curves presenting the combination of the loading time, the test temperature and the acid value of basic ingredients were composed successfully by applying the reduction principle.

U.V. radiation cured finishes and equipment

Drying paint, varnish or lacquer coatings on any substrate is a study in inefficiency if we try to relate the energy input to the energy which actually dries and converts the surface coating.

Corrosion-fatigue strength of sheet materials of alloy D16 with anodic and lacquer coatings

Corrosion-fatigue strength of sheet materials of alloy D16 with anodic and lacquer coatings

Study on Delamination of Brittle Lacquer Coating

In the stress analysis of the brittle lacquer coating applied on engineering structures, it is postulated that the coating completely adheres to their surface. The coating often peels off from the surface, however, even at lower strain than that corresponding to the yield point of mild steels, when the surface is polished to be mirror-like. If the adhesion between the two boundaries fails prior to cracking in the coating, it is too difficult to estimate acculately the applied strain on the structures, since the strain can not be properly transmitted from the surface to the coating.As is well known, adhesion is dominated by several factors which are completely interrelated. From the practical point of view, the author has firstly investigated the influence of surface roughness, which is important in the surface preparation of specimens. Several testing methods are proposed to evaluate the adhesion force, but they can not be applied to brittle lacquer coating, as the coating shows predominantly high brittlenss and cracks in the direction normal to principal tensile strain. To detect the delamination point under compressive load, which corresponds to the strain when the coating begins to peel off from the surface, a new experimental apparatus has been prepared by using composite beams.From the experiments by means of this device, the influence of surface roughness on adhesion has been clarified and the practical range of surface roughness which provides stable adhesion has been determined.

Study on Crack Formation in Brittle Lacquer Coating

In his previous report, the author mentions success in preparing an available brittle lacquer coating which always presented strain sensitivity to circ. 800 micro strain under whatever condition of temperature and humidity without resorting to heat treatment. The difficulty in lacquer coating lies in maintaining its thickness perfectly even. It was particularly the case when the body for coating happened to be engineering structures to be analysed and of complicated construction. Since cracking on the lacquer coating develops in consequence of the strain transmitted from the top surface of the structures to the coating, the properties of crack formation on it will be markedly influenced by the thickness of the coating. The author has investigated, therefore, into the effect of the thickness on both the strain sensitivity and the crack density which are very important factors in practical use.As the result of the study, the following facts have been proved.The thickness of the coating need not be precisely even, since there is scarcely any change either in the strain sensitivity or in the crack density so long as it is restricted within 0.08-0.12mm. Moreover, the behavior of the strain sensitivity under curing process which has been hitherto held as inconceivable is now found as has been caused by fine crystallization of abietic acid used as a basic ingredient of the lacquer coating.

Stresses in various resins cured on glass films

By using Sanzharovskii's method for determining the stresses in lacquer coatings and employing as a model a layer of resin deposited on a glass film, it is possible to simulate the processes that take place in glass-reinforced plastics and determine the stresses that develop in different resins cured under various conditions. The method proposed makes it possible to estimate the effect on the stresses of the shrinkage of the resin, its elasticity, and the difference in the coefficients of thermal expansion of the resin and the glass. Such an investigation is desirable before selecting the composition of the resin, additional organic or mineral fillers and elasticizers, and the optimal curing regime for glass-reinforced plastics.

Study on Brittle Lacquer Coating

Study on Brittle Lacquer Coating

Fingerprint Corrosion on Telephone Switching Equipment

SummaryAs part of an overall study into the use of Chromate passivated zinc plate on telecommunication equipment, it was found necessary to investigate the mechanism of finger-print corrosion as particularly affecting installations in tropical environments. A reaction sequence has been put forward to explain why some constituents of finger grease are more damaging than others. Various proprietary processes were investigated with and without subsequent lacquer coatings. Two lacquer systems were used, a nitrocellulose type and a water-displacing one.The best system for general corrosion resistance is attained by the use of fully passivated bright zinc, but bright passivated zinc is less susceptible to finger-print corrosion due to the lower percentage of hexavalent chromium ions present in the film. A simple test solution has been developed to assess coatings.

Mass Transport In Thin Surface Layers - EffectsFrom A Transport Barrier Zone

Drying of lacquer coatings in wood manufacturing industry is one example of industrial drying of thin surface layers. In this study a waterbome lacquer coated on a particleboard is chosen as an example in order to study the drying process. The thickness of the coating normally varies between 10 and 100 jim. The lacquer coating and the particleboard are regarded as porous media and a two-zone model is used. There is free water transport in the wet zone, and bound water transport in the dried zone. The thickness of the dried zone, in the lacquer coating, and the formation time of the zone are varied, in order to evaluate the effect on the water transport in the lacquer coating and the particle board. A finite difference model is used to calculate the water transport in the lacquer coating and the particleboard. Prediction of drying time by the present model is discussed for different values of the mass diffusivity coefficient. However, in order to have a more accurate model a moving evaporation boundary must be used. The assumption that the particleboard is below the fibre saturation point during drying is acceptable in these calculations. Predictions of fibre swelling in the particleboard may, however, be unreliable since the hydroscopic nature of the material is not taken into account in the present model. Transactions on Engineering Sciences vol 20, © 1998 WIT Press, www.witpress.com, ISSN 1743-3533

A Study on Brittle Lacquer Coating to Improve Strain Sensitivity

A Study on Brittle Lacquer Coating to Improve Strain Sensitivity

Stress transmitted through mouth protectors

Brittle lacquer coatings on maxillary models were used to evaluate the effectiveness of mouth protectors in protecting the teeth from strain as a result of impact blows. Among the mouth protectors found to be most effective are the mouth-formed ones. Brittle lacquer coatings on maxillary models were used to evaluate the effectiveness of mouth protectors in protecting the teeth from strain as a result of impact blows. Among the mouth protectors found to be most effective are the mouth-formed ones.

MEASUREMENT OF STRESSES IN FIXED-BRIDGE RESTORATIONS USING A BRITTLE COATING TECHNIQUE.

Three principal methods used to study stresses in materials are photoelastic stress analysis, brittle lacquer-coating techniques, and electronic strain gauges. A number of studies have been conducted using models and the photoelastic method' to examine stress patterns in oneand two-surface inlays, complete dentures, teeth and supporting bone, and rests used in partial dentures. Strain gauges4 9-13 have been used in the evaluations of stresses of mastication, but brittle lacquer coatings have not been used to any extent in the measurement of stresses in dental restorations.4 Brittle lacquers have been used in the study of stresses in the human mandible and other bones under static and dynamic loading.14' The brittle lacquer coatings are particularly useful in detecting and measuring strains at the surface of the structure as well as indicating the direction and sequence of the tensile strains. Although the method is not as accurate as strain gauges, it is an excellent means of obtaining an over-all picture of the pattern of the stress distribution. The information obtained using brittle lacquers may be used, therefore, as a basis for more detailed studies with strain gauges. It was the purpose of this investigation to study the general stress patterns in typical fixedbridge restorations using various static loading conditions and a brittle lacquer-coating technique.

Interaction between Brittle Lacquer Coating and Medium Improving Strain Sensitivity

In the previous paper, the present author gave a description of a fundamental investigation about the molecular structure and the mechanism of “Solvent-Cracking” on brittle lacquer coating prepared from calcium rosin as a basic ingredient, in order to find out the effectiveness improving strain sensitivity of coating contacted with various media.In this report, the interaction between the coating and various media is analyzed by considering the factors as follows:The analysis of interaction will be comparatively easy, if the media are non-polar, but these media used for improvement of strain sensitivity are generally polar such as polyfunctional alcohols having a complicated molecular shape and strong association tendency.As the result, it was been concluded that the interaction between coating and media, namely, the effectiveness improving the strain sensitivity of coating is proportional logarithmically to the initial dissolving rate of various media.

The Measurement of Strain in Components of Complicated Form by Brittle Lacquer Coatings

The Measurement of Strain in Components of Complicated Form by Brittle Lacquer Coatings

On the Elasticized Japanese Lacquer Coating and Its Electrical Chactistics

On the Elasticized Japanese Lacquer Coating and Its Electrical Chactistics

Electrical and Thermal Properties of Japanese Lacquer Coating with Phenolic Resin and Amber

Electrical and Thermal Properties of Japanese Lacquer Coating with Phenolic Resin and Amber

VOLATILE SOLVENTS AS A PROBLEM IN INDUSTRIAL MEDICINE

The increasing prominence of volatile solvents in modern industrial processes emphasizes the need of early recognition of any toxic action on exposed workers which, if recognized, may lead to corrective measures being adopted. Within the past few years the number of newly perfected solvents has steadily mounted, until today well in excess of 300 are in common use, contrasted with a bare half dozen used twenty years ago. One or more of the solvents are used in ever increasing quantity and variety in nearly every manufacturing industry today either as a solvent or as a diluent. They are employed as cleaning or degreasing agents, in lacquer coatings, in dyes and cement, as plasticizers, and as solvents of cellulose and gums of various kinds in a myriad of synthetic finishing materials. The volatile solvent vapors enter the body chiefly through the respiratory passages, but appreciable quantities may either be ingested or