Sieben und Filtern in der Lackindustrie I Sieben mit monophilen Geweben und entsprechenden maschinellen Einrichtungen

Sieving and Filtration in the Paint Industry I: Sieving with Monophilic Tissues and the Corresponding Mechanical Equipment Sieving and filtering in the paint industry are rather in-efficient processes in the chain of production, and hence they deserve considerable attention. One should take into consideration the qualitative and quantitative performance of the tissues that are commercially available for sieving and filtration. Also the machinery suitable for improving the performance should be explored. The use of Perlon and Nylon tissues for filtration in open and closed filter systems is discussed.     

Moderne Abfüll- und Verpackungsstraße in der Lackindustrie

Modern Filling and Packaging Lines in the Paint Industry Cost of labour has become very high even in the paint industry. Especially in the filling and packaging sections the cost of labour is high. In these sections it is worthwhile to attempt to reduce the costs by suitable measures. In the paint industry of Scandinavia in large medium as well as small plants packaging lines have been installed which might be ideally suited for filling, packaging and storing of paints.     

Fette als Rohstoff der Lackindustrie

Fats as Raw Materials for Paint Industry Fats are even today important raw materials for the paint industry. Roughly one tenth of the world production of fatty matter is processed for paints. More than 50% of paints in the true sense are manufactured on fat basis; thereby linseed oil plays a dominating role. With reference to the total amount of paints produced in Germany, the proportion of fats employed decreased from ca. 36% to 27% in the last ten years inspite of an increase in the absolute amount of fats (64% increase). Simultaneously, a considerable increase took place in the proportion of oil-free synthetic resin paints. The possible causes of these displacements in proportions are discussed. Apart from their customary uses, special fat-products have found new fields of application in paints, i. e. reactive paints, and hence in the forthcoming decade one may expect fats to constitute 50% of raw materials for paints. The steadily increasing demand for edible fats leads to thoughts, regarding how the fats that are suitable for human nutrition should be secured for this particular sphere without impairing the supply of fats for technical purposes.     

Abtrennung und Extraktion von Bleicherde in geschlossenen Filtern

Separation and Extraction of Bleaching Earth in Closed Filters Application of closed disc filters with centrifugal discharge in filtration and extraction of bleaching earth is described. This type of filter offers advantages, amongst others, those due to exclusion of air and the possibility of extraction of oilcontaining bleaching earth cake “in situ”. Short time interval between starting up and emergence of clear filtrate, and optimum capacities are attained, if pore size of filter membrane is chosen at two to four times the average particle size of solids. Traces of soap contained in the oil have undesirable effect on rate of filtration. It is advantageous to carry out the extraction in two stages, namely, first with dilute miscella, and then with pure solvent. A good quality extracted oil is obtained with hexane as solvent. A combined filtration and extraction plant, attached to an edible fat refinery, consists of 6 filters, each having 20 m² filtration surface. A plant for miscella distillation, and an inert gas plant for generation of protective gas used for compressing, are connected as well. The process is controlled by programmed operation. Filtration capacity of cottonseed oil with 1% bleaching earth with subsequent extraction of filter cake is 340 1/m² · h.     

Probleme bei der Filtration unter extremen Gas- und Staubbedingungen

Filtration problems under extreme conditions . Filtering separators belong to the high-performance separators and their significance in dust extraction techniques is increasing. They are distinguished by offering almost any desired efficiency of separation which property, on use of appropriate filter media, is also preserved under fluctuating working conditions with regard to dust content in the crude gas, size of the dust particles to be separated, and the rate of gas flow. In order to exploit these advantages also under extreme conditions of gas and dust attempts were made in recent years to extend the operating range by the development of new filter media. Among the applications deserving mention are the fly-ash collection in coal-fired power plants and the dust separation under high temperatures for new power technologies. The present state of the art and experience gained so far are presented.     

Bestimmung der pigment-verteilung in kunststoffen mit hilfe der neutronenaktivierung und autoradiographie

Methods used in plastics processing to determine the distribution of additives in polymers are inadequate up to now, because small differences in the distribution cannot be detected. Using neutron-activation of activable components of the additives and autoradiography as recording method, macroscopic and microscopic differences of the distribution can be evaluated quantitatively. This technique can be applied on transparent or non-transparent specimens. The determinable and resolvable concentrations of additives are small. By example of a pigmented poly-styrene with an activable content of 0.0013% Cu (by weight) the method and obtainable results are described.     

Experimentelle und theoretische Untersuchungen zur Filtration mit überlagerter Sedimentation in Drucknutschen

Sedimentation superimposed on industrial cake filtration leads to longer filtration times and often has a detrimental effect on subsequent process steps such as washing and demoisturing. The influence of sedimentation is seldom recognised in laboratory filtration experiments. Methods are presented for evaluation of pressure filter experiments with superimposed sedimentation which avoid the error made in the usual evaluation methods. For the case of zone sedimentation the article presents a graphical evaluation and a numerical method of modelling permitting scale up to any desired cake height. In superimposed classifying sedimentation simultaneous measurement of filtrate volume and cake height provide information about local variation in filter cake resistance. It is shown for a model system that, owing to sedimentation, the cake resistance shows a minimum at mean cake height and increases rapidly towards greater heights. The local cake resistance corelates with particle size distributions measured for layers of a horizontally cut filter cake. The method of evaluation presented permints determination of the flow resistance of the uppermost layers of a cake and hence estimation of the gas pressure necessary for demoisturing. The profiles of local filter cake resistance show that the relative cake layering is largely independent of the level of suspension filling. A scale-up model is presented for use in those cases where classifying sedimentation cannot be suppressed.     

Zur Aminolyse von Bis-Imidoylchloriden der Oxalsäure II. Umsetzung mit Diaminen und Aminoalkoholen

On the Aminolysis of Bis-Imidoylchlorides of Oxalic Acid. II. Reaction with Aliphatic Diamines and Aminoalcohols The aminolysis of bis-imidoylchloride 1 derived from oxalic acid with several diamines and aminoalcohols was investigated. At room temperature diamines 2 as well as aminoalcohols 7 give mainly the cyclic amidines 3 and mixed amidine-imidates 8 in moderately up to good yields. While cis-1,2-diaminocyclohexane yields at room temperature the bicyclic amidine 3a , the trans isomer reacts to 3b only when heated for several hours. Depending on the conditions, the racemic 1,2-diaminopropane 2h gives derivatives of pyrazine 3h or the open-chain amidine 5 resulting from an oxidative aromatization and subsequent hydrolysis. Histamine 2i and 1,8-diamino-3,6-dioxaoctane 2p react selectively with 1 to seven- respectively twelve-membered heterocycles 3i and 3p. The mixed aliphatic and aromatic diamines 2n, o show an anomalous behaviour leading to 2,2′-bis-chinazolines 3n, o . In comparison with acyclic oxalic amidines the new cyclic derivatives show less molecular dynamic in their nmr spectra. In some cases, a s-trans-arrangement of the amidine substructure was observed.     

Konformationsuntersuchungen mit Hilfe der 13C-NMR-Spektroskopie. II. Vorzugskonformationen,Substituenteneffekte und Barrieren der Ringinversion von Ketalen methylsubstituierter Cyclohexanone

Conformational Investigations by Means of ¹³C-N.M.R.-Spectroscopy. II. Conformational Preferences; Substituent Effects and Barriers to Ring Inversion in the Ketals of Methyl-substituted Cyclohexanones The comparison of the experimental determined ¹³C-NMR-chemical shifts of 8 ketal s with those, which were calculated by the well-known additivity rules allows some conclusions about the conformation of the compounds respectively about γ-gauche-effects and δ-syn-axial interactions in question. ¹³C-NMR-measurements at low temperatures make it possible to determine the barriers to ring inversion of some ketals. The obtained values are discussed in dependence of the substitution pattern.     

Solvolyse- und umesterungsreaktionen bei der vernetzung von alkyd- und acrylatharzen mit melaminvernetzern

One acrylic and different alkyd resins were cured with a melamin resin. Technical properties, swelling degrees, relativ IR-absorbances, and volatiles in the waste gas were determined quantitatively. From these data the amount of iso-butanol for the crosslinking and selfcondensation reactions can be calculated. In addition it was observed a solvolysis reaction of the alkyd resin and a transesterification reaction of the acrylic resin because of the reaction of the ester groups with the iso-butanol eliminated from melamine resin. Evidence is given for the solvolysis reaction by investigation of the specific cleavage products by means of IR, GPC, and GC/MS measurements. A pathway for the solvolysis reaction is proposed.     

Entfettung und Nachfetten der Kopfhaut und der Haare nach Kopfwäsche mit verschiedenen Tensiden

Defatting and Fat Regeneration of Scalp and Hair After Shampooing with Various Surfactants Defatting and fat regeneration of scalp and hair after shampooing with the anionic surfactant sodium polyethyleneglycol laurylethersulfate and the non-ionic surfactant polyoxyethylene sorbitolmonolaurate were studied on 32 subjects. The extent of defatting by the anionic surfactant was considerably higher than by the non-ionic surfactant. Two days after shampooing, three-fourth of the total lipids, taking together the lipids of scalp and hair, were regenerated. Considering the hair lipids alone, 57.77% and 64.78% of the lipids were regenerated. The initial values were attained on the fifth day. Both on the second and fifth day no significant difference in lipid content was observed for the two surfactants. These investigations fail to show that the application of a specific surfactant has any advantage in the treatment of scalp seborrhea. However, shampooing at intervals of two days appears to be meaningful.     

Kinetik und Mechanismus der Reaktion von Arylisocyanaten mit Alkylhydroperoxiden

Kinetics and Mechanism of the Reaction of Aryl Isocyanates with Alkyl Hydroperoxides Sec-alkyl peroxycarbamates, prepared from phenyl isocyanate and sec-alkyl hydroperoxides, are instable at normal temperatures and decompose to yield ketones, carbon dioxide and aniline which reacts further to diphenylurea. The reactions of phenyl isocyanate with tetraline hydroperoxide, t-butyl hydroperoxide, aniline, and tert.-butanol in dioxane have been studied kinetically and the catalytic constants of diazabicyclooctane, triethylamine, and stannous octoate as catalysts have been determined. Rate constants of the reactions with hydroperoxides decrease with increasing hydroperoxide concentration caused by association of the catalyst with the hydroperoxide. Compared to their basicities, alkyl hydroperoxides are very reactive towards isocyanates.     

Rauchgasreinigung mit Reststoffbehandlung und Wertstoffgewinnung in der Abfallverbrennung — Stand und Tendenzen

The design of flue gas treatment equipment in municipal waste incineration plants worldwide varies according to the requirements with respect to pollutant emissions and resource recovery. Various combinations of individual separation processes may be encountered, such as dry particle separation, gas absorption (wet or dry), adsorption, catalytic or thermal conversion. The present comparison of different basic process alternatives indicates that firstly any degree of pollutant removal can be achieved by the available process technologies with corresponding expenditure of money and energy demand, secondly, German plants generally are more complex than plants in other countries due to more stringent separation and resource recovery efficiency requirements, and thirdly, a trend can presently be seen towards more simple and cheaper processes with simultaneous separation of several pollutants in one process step.