KRONOS Technical Service Worldwide

Transcription

1 KRONOS Technical Service Worldwide

2 The purpose of the Technical Service Department at KRONOS is to bring together basic research knowledge and individual customer requirements. It is with this objective in mind that we work with our customers by providing continuous customer support and solutions to their problems. As a specialist in TiO 2, KRONOS has qualified chemists, engineers and technicians who know how to improve user systems. The standard equipment at KRONOS includes modern, generously equipped laboratories and laboratory-scale machines comparable to those typically employed by TiO 2 users. Representation on national and international technical committees is a further indication of KRONOS leadership and commitment to the industry. KRONOS technical applications know-how At our customers service The range of services offered by the KRONOS Technical Service Department encompasses: Technical consulting on specific and safe uses of KRONOS TiO 2 pigments. Assistance in pigment selection with the aim of optimising processes and improving application systems. On-site training of new personnel and presentations of applications on customers premises. Publication of company articles and papers on product and application-related subjects. Constant contact with raw material suppliers, in order to detect market trends. Presence at international technical exhibitions

3 Coatings Easy incorporation, optimum hiding power and tin-ting strength and good gloss development are just a few of the demands a TiO 2 pigment has to meet in the coatings field. Our Technical Service Department can support you in choosing the most cost-effective pigment for your intended application. Here are a few examples: Optimisation of the dispersion process. By dispersing the pigment in a bead mill under test conditions, we examine which KRONOS TiO 2 grade can be incorporated into your application system in the shortest possible time and with the greatest energy savings. We produce water-based paints in a vacuum dissolver to avoid undesirable air which might be sucked into the mill base. Determination of hiding power and tinting strength. The efficiency of a pigment can be indicated by the brightness values of a paint film measured over black and white substrates. Working on this basis, we determine, for example, the contrast ratio and the scattering power as a measure of the hiding power. Gloss measurement. The right grade can improve the quality of a coating, especially in high-gloss paints. We perform measurements of applied industrial paint films, e.g. of automotive finishes, so that we can make recommendations for the best possible gloss setting with minimum gloss haze. Optimisation of stoving conditions. A high-performance oven specially designed for coil coatings, for instance, enables realistic results to be obtained as a basis for optimising formulations. The oven operates at a high heating rate and with a great variety of temperature profiles, allowing us to simulate even unusual demands on the film stoving conditions.

4 Examination of adhesion failures. Measuring the surface tension of paints and coatings with a tensiometer gives us information about the wettability of various substrates. Testing of abrasion properties. Printing ink manufacturers frequently ask about the effect of TiO 2 pigments on printing presses. To protect this equipment, we carry out comparative tests of the abrasiveness of pigmented liquid materials, such as gravure inks, before recommending a pigment. Optimisation of production processes as a result of visual assessment. Coating defects or contaminations in paint films and material surfaces are detected under a lightoptical microscope and documented in photographs. Based on these observations and discussions of the corresponding relationships, we give our customers indications of how they can improve their production process and the quality of their products. Pigment comparisons in powder coatings. The example of powdercoated reflection surfaces on lamps shows how important it is to choose the correct TiO 2 pigment. This application requires maximum opacity with the lowest possible film thickness and high brightness and also a markedly bluish undertone (bluish white) to give maximum light reflection. The surface quality of powder coatings is also important. It is determined by a visual assessment of the levelling and gloss of the coating after curing in a stoving oven, as well as by measurement of the coat elasticity (Erichsen cupping test). Our powder coating laboratory puts us in a position to produce coating powders, classify them by particle size, apply the powders electrostatically and stove them.

5 The plastics laboratory of the KRONOS Technical Service Department is equipped with an impressive array of machines for incorporating the titanium dioxide pigments into a wide variety of polymer We then use a spectrophotometer to determine the optical properties of the plastics films produced in this way. Measurement of the opacity of plastic films. The light transmission of pigmented films, which is dependent Plastics on the scattering power of the TiO 2 grade, is determined using a transmission measuring instrument. These films are produced on a chill roll. matrices. The pigmented plastic specimens can be tested not only for pigmentary properties, but also for polymer-related characteristics. Here are a few examples: Testing the state of dispersion. We produce polyethylene masterbatches with the desired pigment concentration, either in a continuous process or by a batch process. This permits us to simulate specific customer conditions. The sieve residue and the pressure buildup resulting from extrusion of the PE masterbatches, or specks in PE films, allow us to draw conclusions as to the state of dispersion of the pigment. Assessment of optical properties. To be able to recommend the most suitable pigment, we incorporate TiO 2 pigments into thermoplastics (preferably PVC) using an automatic roller mill. Determination of lacing. The release of volatile constituents from the pigment surface may lead to the formation of holes during film blowing. To check this, we produce very thin films on our blowing machine. Optimisation of flow properties. TiO 2 pigments may affect the flow properties of polymer melts either physically (through filling) or chemically (through depolymerisation). The viscosity of pigmented plastics is described by the melt volume rate, the melt flow index and the melt density under defined pressure and temperature conditions. Based on this information, the polymer used can be combined with the most suitable titanium dioxide grade and the most effective additive and adjusted to suit the end-use.

6 Paper The equipment available in our paper laboratory enables us to test titanium dioxide in a wide variety of of paper applications. This applies to both TiO 2 addition to the paper stock and pigmentation in cardboard and paper coatings. A particular focus of our activities is the testing of TiO 2 pigments for paper laminates. White and coloured pigmented papers. Two semi-automatic handsheet formers allow us to produce white and coloured papers according to set formulations and under realistic conditions. In this context, the handsheets can be used to evaluate the retention properties of the titanium dioxide grade used. The concentrations of titanium dioxide and, optionally, calcium carbonate in the handsheets can be determined rapidly and without destructive ashing of the paper, by using a paper analyser with an Fe-55 emitter. Paper laminates. A fully automatic paper laminate press permits us to produce paper laminates from impregnated decorative papers at controlled temperatures and pressures. The optical properties of the laminates are measured on an ELREPHO 3300 spectrophotometer. The laminates are also exposed to a greying test in a Xenotest 150S apparatus. Based on these tests, we develop pigments with optimised optical properties and high greying resistance. With a Magendanz SZ2 instrument, we are in a position to check zeta potentials of aqueous TiO 2 suspensions and of pigmented paper stock. Coating of cardboard and fine paper. The cost-effectiveness of TiO 2 pigments in paper coatings results from their high whiteness and opacity, together with good dispersibility. To test these properties, we are equipped with a laboratory barcoater, precise cardboard punch and different types of spectrophotometers.

7 The quality of man-made fibres is strongly influenced by a relatively small amount of TiO 2 pigment which is needed for delustering. The quality of the anatase pigments is crucial for the colour, abrasiveness and lightfastness of the fibres, the lifespan of suspension and polymer filters, and the number of filament breakages during production. Elaborate testing enables us to identify suitable pigments which meet the stringent requirements specified. Fibres Determination of coarse particles of TiO 2 pigments. As required, we run sedimentation tests in aqueous and organic media. These tests include, for example, the Atterberg method or those using a sedimentation balance. Various types of stirrers and dispersing equipment are available for preparing the titanium dioxide suspensions, e.g. low-shear magnetic or propeller stirrers, rotor/stator dispersers, toothed-disc impeller mixers or highshear bead mills. Measurement of optical properties. A hydraulic powder press is used to compress the pigments into tablets before measuring their optical properties on a spectrophotometer. Testing the abrasiveness of TiO 2 pigments. We determine the abrasiveness of TiO 2 pigments with the aid of a copper-bar abrasion tester. In this method, two copper bars are drawn back and forth over a strip of material soaked with a specially prepared TiO 2 suspension. The weight loss of the bars is a measure of the abrasiveness of the pigment.

8 Paper The equipment available in our paper laboratory enables us to test titanium dioxide in a wide variety of of paper applications. This applies to both TiO 2 addition to the paper stock and pigmentation in cardboard and paper coatings. A particular focus of our activities is the testing of TiO 2 pigments for paper laminates. White and coloured pigmented papers. Two semi-automatic handsheet formers allow us to produce white and coloured papers according to set formulations and under realistic conditions. In this context, the handsheets can be used to evaluate the retention properties of the titanium dioxide grade used. The concentrations of titanium dioxide and, optionally, calcium carbonate in the handsheets can be determined rapidly and without destructive ashing of the paper, by using a paper analyser with an Fe-55 emitter. Paper laminates. A fully automatic paper laminate press permits us to produce paper laminates from impregnated decorative papers at controlled temperatures and pressures. The optical properties of the laminates are measured on an ELREPHO 3300 spectrophotometer. The laminates are also exposed to a greying test in a Xenotest 150S apparatus. Based on these tests, we develop pigments with optimised optical properties and high greying resistance. With a Magendanz SZ2 instrument, we are in a position to check zeta potentials of aqueous TiO 2 suspensions and of pigmented paper stock. Coating of cardboard and fine paper. The cost-effectiveness of TiO 2 pigments in paper coatings results from their high whiteness and opacity, together with good dispersibility. To test these properties, we are equipped with a laboratory barcoater, precise cardboard punch and different types of spectrophotometers.

9 The quality of man-made fibres is strongly influenced by a relatively small amount of TiO 2 pigment which is needed for delustering. The quality of the anatase pigments is crucial for the colour, abrasiveness and lightfastness of the fibres, the lifespan of suspension and polymer filters, and the number of filament breakages during production. Elaborate testing enables us to identify suitable pigments which meet the stringent requirements specified. Fibres Determination of coarse particles of TiO 2 pigments. As required, we run sedimentation tests in aqueous and organic media. These tests include, for example, the Atterberg method or those using a sedimentation balance. Various types of stirrers and dispersing equipment are available for preparing the titanium dioxide suspensions, e.g. low-shear magnetic or propeller stirrers, rotor/stator dispersers, toothed-disc impeller mixers or highshear bead mills. Measurement of optical properties. A hydraulic powder press is used to compress the pigments into tablets before measuring their optical properties on a spectrophotometer. Testing the abrasiveness of TiO 2 pigments. We determine the abrasiveness of TiO 2 pigments with the aid of a copper-bar abrasion tester. In this method, two copper bars are drawn back and forth over a strip of material soaked with a specially prepared TiO 2 suspension. The weight loss of the bars is a measure of the abrasiveness of the pigment.

10 Weathering tests Titanium dioxide pigments are good UV absorbers, although they display various degrees of photocatalytic activity. Therefore, weathering and photostability tests are of great importance. In these tests, we measure gloss retention, chalk resistance, colourfastness, embrittlement, contamination, tensile and impact strength. We are equipped to run long-term outdoor exposure tests, as well as accelerated weathering tests. Outdoor exposure. To test the weather resistance of their products, KRONOS customers can also expose panels of their own at our outdoor testing station in Leverkusen-Engstenberg, Germany. Moreover, we have panels exposed in Bandol, France, and in Florida and Arizona, USA, so that we can allow for the weather effects of other climates. The exposure results relating to pigment stability are sent to us at regular intervals and are taken into account in product development and our recommendation to customers. Accelerated weathering. The laboratory equipment of KRONOS Technical Service permits reliable accelerated weathering of coatings and plastics in machines such as the carbon-arc Weather-Ometer, xenon Weather- Ometer, QUV or Suntest CPS machines.