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Assessment of glass etching/corrosion in dishwashers within the hour - new opportunities when YKI merges with
SP KM.
1SP Chemistry, Materials and Surfaces, Stockholm, Sweden and 2Kemibolaget i Bromma AB, Stockholm, Sweden
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Lubica Macakova,1 Mikael Kjellin1, Martin Andersson,1 Leif Löf2, Halina Wnukowska2
Change of legal status and name from 1st January 2013
Institute for Surface Chemistry (YKI), Stockholm
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SP Chemistry and Materials, Borås
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SP Chemistry, Materials and Surfaces (Stockholm & Borås)
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The SP Group is wholly owned by RISE (100% Government owned, not for profit corp.)
Subsidiaries 7 (AstaZero, CBI, Glafo, JTI, SIK, SMP, SPPD)
Employees 1 200
Revenues Euro 120 million
Customers > 10 000
Ph.D. and Lic. Eng. approx. 300
Ph.D. students approx. 80
Degree projects approx. 70
Adjunct professors 26
About SP
About SP Chemistry, Materials and Surfaces
The new unit will have approx. 160 employees Two main sites; Borås and Stockholm in Sweden A balance between research, innovation and services PhD and Lic Eng 63 PhD students 14 Adjunct Professors 2 International business ~30%
Our client base are found in industry, academia and public organizations both in Sweden and internationally.
Business at SP Chemistry, Material and Surfaces
Examples of analytical techniques
Surface tension Contact angle/Pendant drop and wetting Dynamic surface tension Tensiometer Adsorption at surfaces Quartz Crystal Microbalance (QCM-D) X-ray Photoelectron Spectroscopy (XPS) Dual Polarization Interferometry (DPI) Ellipsometry Friction and lubrication Mini Traction machine Atomic Force Microscopy (AFM) (Force/Friction, Imaging)
Particles and Dynamic drainage apparatus dispersions Dynamic light scattering Laser diffraction Zetaprobe Turbiscan Rheology Rheometer Thermal analyses Thermogravimetric Analyzers (TGA) Differential Scanning Calorimetry (DSC)
Microscopy and surface Atomic Force Microscopy (AFM) topography Environmental Scanning Electron Microscopy (ESEM) 3D Optical surface profiler Chemistry at surfaces Confocal Raman microscopy X-ray Photoelectron Spectroscopy (XPS) Infrared analysis (IR) Environmental Scanning Electron Microscopy/Energy Dispersive X-ray analysis (ESEM/EDX) Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS)
Chemical Analysis and Material Testing
Material composition and identification of constituents
Emission of organic compounds from construction materials, etc.
Environmentally related properties, e.g. heavy metal content
Air quality of indoor environments
Material tests and analyses of mechanical properties
Microstructure
Chemical composition
Sustainability/degradability
Surface analysis and surface properties
Accelerated ageing
Corrosion testing
Glass corrosion
Corrosion of Glass, Ceramics and Ceramic Superconductors; Edited by: Clark, D.E.; Zoitos, B.K. © 1992 William Andrew Publishing/Noyes Advanced Materials Research 2008, volumes: 39-40 Main Theme: Glass – The Challenge for the 21st Century , edited by M. Liška, D. Galusek, R. Klement and V. Petrušková • Orhan et al. Advanced Materials Research 2008, 39-40, p. 317-322 • Petruskova et al. Advanced Materials Research 2008, 39-40, p. 323-328
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Line corrosion and partial corrosion in detail Line corrosion: • Is caused by the contact of glass with 'hot
production' equipment • Cannot be observed at new, never washed glasses • Chemical inhomogeneity in the glass lead to
different degrees of glass removal during the alkaline attack
• The glass around those areas gets removed quicker. The line structure appears.
Partial corrosion: • Is caused by chemical changes at treated areas of
fire polished glasses. • Cannot be observed at new, never dish washed
glasses • Appears first after a higher number of washing
cycles • Clouding occurs due to light dispersion at
microscopically small holes 9
• Corrosion after some 1000 wash cycles can be related to the long range granular structure of glass, which is believed to be formed by thermal density fluctuation during production.
• During washing both water and detergents act as
weak etchants, first eroding the smooth glass skin, then revealing the granular structure. As soon as the linkages between the granules are entirely broken by the etching, holes will manifest themselves at these sites. When the size of the holes (the hole width) reaches the half of the light wavelength, light scattering occurs and the glass seems cloudy.
Full corrosion/etching of the glass surface
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What causes the glass corrosion?
• Changes of glass surface composition, especially the depletion of alkali and alkali earth ions, mainly Na+ and K+ , Ca2+
• Hydrolysis of silicate network at high pH • Release of silicate material (dissolution)
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Factors influencing glass corrosion during dishwashing
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Glass corrosion
Time and temperature • dishwashing program
Water quality • hard/soft • salt composition
Quality of glassware • composition • manufacturing
process
Mechanical action • placement in dishwasher • water flow pattern
Pre-use storage conditions • humidity • temperature
Chemistry • Composition of cleaning
formulations (powders, liquids, tablets)
Time of eco-friendly reformulations
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• Regulation (EU) No 259/2012 of the European Parliament and of the Council of 14 March 2012 amending the Regulation (EC) No 648/2004 as regards the use of phosphates and other phosphorus compounds in consumer laundry detergents and consumer automatic dishwasher detergents
• Detergents for automatic dishwashers - limit value
of 0.3 grams of phosphorus in a standard dosage will apply from 1 January 2017
Novel, often poly-carbonate based strong chelating agents • Strong decalcifications • Contribution to prevention of soil re-deposition • Good performance in cleaning efficiency tests But!
Replacement for phosphates
Strong decalcification => depletion of cations from glass matrix => more corrosion
Ca2+ Ca2+
Ca2+
Ca2+
Ca2+
Ca2+
Ca2+
Ca2+
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Towards a novel formulation with a minimized glass corrosion activity
Optimisation with an aim to maximise cleaning effect
Novel phosphate free formulation
Optimisation with an aim to minimize glass corrosion a) Comparison with market leading brands b) Identification of the most corrosive components c) Screening for milder/less corrosive replacements/combinations
Formulation adjustment & “in-use” tests
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Kemibolaget i Bromma AB aims to develop a phosphate free product with both maximum cleaning efficiency and minimal glass corrosion effect
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Conventional glass etching tests
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• Optical evaluation after many
washing cycles, typically between 50 -1000 with some 2 hours /cycle
• Testing time: months
• Advantage: real in-use situation • Disadvantage: time consuming
nfCm ∆
−=∆
Rapid glass etching tests employing QCM-D Quartz Crystal Microbalance with Dissipation monitoring, QCM-DTM
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• Quantitate gravimetric evaluation possible after as little exposer time as 2 hours (etched off amount)
• Flow and temperature control
• Possible to obtain layer thickness of the etched off layer
• Advantage: short testing time • Disadvantage: model system
necessary (glass covered sensor crystals)
Rodahl et.al; Review of Sci.Instruments 1995, 66, p. 3924-3930
QuartzGold Electrode
Gold Electrode
Gold electrode with sputtered glass
DMDAO C12E6
Nonionic surfactant C12E6 is more efficient in removal of oily triolein dirt than zwitterionic surfactant DMDAO.
Previous use of the QCM-D in the cleaning area. Removal of oily soil (triolein) from gold surface.
Experimental set up. Glass etching tests.
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Substrate: 100 nm thick soda-lime glass sputtered on a sensor electrode (QSX 999, Q-sense) Dishwashing solutions: New formulation – Kemibolaget i Bromma AB, c = 1 dose/4l, pH = 10.5 Brand I, c = 1 tablet/4l, pH =10.2 Brand II, c = 1 tablet/4l, pH = 10.4 New formulation without complexing agent X, c = 1 dose/4l, pH = 10.5 Exposure time: 2 hours during continuous flow of dishwashing liquid Temperature: 50°C
Glass etching followed by QCM-D
20 nfCm ∆
−=∆
Sauerbrey; Z.Phys.1959, 155, p. 206-222
3 different formulations on 3 different soda-lime glass sensors
21 Etching rate: Tens of nm in 2 hours Etching not yet detectable optically
Comparison of the new formulation with commercial brands (3 different soda-lime substrates)
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Identification of (one of) the formulation components leading to enhanced glass etching
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Conclusions
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• Quartz Crystal Microbalance (QCM-D) technique in combination with custom-made sputtered glass substrates offers a possibility of a rapid screening of dishwashing formulations in terms of their glass etching tendency.
• With Q-Sense E4 equipment (Q-sense), it is currently possible to evaluate
up to 4 samples per 1 day. Common conventional method of evaluation of glass etching tendency is repetitive dishwashing (from 100 up to 1000 times), which often takes up to couple of months after which the samples are evaluated optically. This means that the QCM-D method is up to about 100 times quicker than conventional methods.
• The method enables quantitative comparison of dishwashing
formulations.
• Different types of glass surfaces are possible to evaluate (soda-lime, borosilicate, crystal etc.)
Thank you for your attention
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SP Chemistry, Materials and Surfaces Drottning Kristinas väg 45
Stockholm, Sweden www.sp.se
