PROMAXON as a. in Epoxy Resins _Promaxon Thixotropic Additive.indd 1 19/08/09 14:16

Transcription

1 PROMAXON as a Thixotropic Additive in Epoxy Resins _Promaxon Thixotropic Additive.indd 1 19/08/09 14:16

2 PROMAXON as a Thixotropic Additive in Epoxy Resins Introduction PROMAXON is a calcium silicate hydrate. It is the result of a hydrothermal synthesis through which spherical particles are obtained, by means of a special crystallization process and controlled crystal growth. The open inner structure of these particles is surrounded by an outer shell of close knitted crystals. This unique particle corresponds to the known mineral xonotlite, of which the chemical synthesis can be written as: 6Ca(OH)2 + 6 SiO2 + H2O > 6 CaO SiO2 H2O + 6H20 It appears as a white powder which is commercialized under the trade name PROMAXON. Specifications SiO CaO 42.9 Al2O3 MgO 0.3 Fe2O3 1.1 K2O Na2O L.o.i. 6.1 Bulk density [g/l] 100 Why PROMAXON? PROMAXON is a very interesting thixotropic agent in epoxy systems because of following properties: 200µm Tapped density [g/l] 160 Average particle size [µm] 60 Moisture content <3 ph value [-] 10 Specific surface [m²/g] 60 Thermal stability [ C] 750 (dehydration) [ C] 1540 (melting) Ca6Si6O17(OH)2 Picture 1: PROMAXON spherical particles easy to use less dust easy to disperse easy for postthixotropizing on site no risk of overdispersing limited moisture absorption inorganic heat resistant excellent surface appearance favorable price/performance ratio excellent stock stability The performances of PROMAXON are demonstrated in a number of practical examples, which have been tested in our laboratories. 100µm Picture 2: PROMAXON cut particles with visible inner structure 10µm Picture 3: PROMAXON detailed open particle _Promaxon Thixotropic Additive.indd /08/09 14:16

3 Practical examples Practical examples High filled systems filled systems SCHERING-RESIN HOECHST-RESIN HOECHST-RESIN Schering-resin in an epoxy mortar and filled with Hoechst-resin in an epoxy mortar. An hydrophobic Waterbased epoxy coating quartzflour, PROMAXON D is evaluated in pyrogenic silica is compared to PROMAXON. Hoechst-resin in a waterbased epoxy coating used comparison with pyrogenicsilica. A relatively low concentration is needed to obtain to paint concrete surfaces. When comparing an Tests with PROMAXON D established clearly that an anti-sag situation for PROMAXON. addition of 2 pph PROMAXON D with 1 pph a larger particle size is advantageous for this pyrogenic silica, a higher viscosity level is achieved at application. lower mixing speed. The STI is increased resulting in a comparable viscosity at higher mixing speed. High filled epoxy mortar High filled epoxy mortar Mixture Mixture Component A Component B Europox % Beckopox EP parts Beckopox hardener EH parts Beckopox EP parts Eurodur % Beckopox hardener 10.0 parts TiO2 RN parts Beckopox VEP parts Quartz flour % Quartz flour W parts Iron oxide black 12.5 parts Water 67.0 parts Quartz sand mm parts EWO-weiss normal 76.0 parts Ratio A/B: 60/40 Micro-talc ATI 54.0 parts PROMAXON D pyrog. silica PROMAXON D 2.00 % additol XW parts Comp A 2 pph 1 pph Pyrogenic Silica 7.50 % PROMAXON D 4.0 parts additol XW parts addition for non-sagging in the U-profile anti-sag test Pyrog. Silica (hydrophobic) 3.0 parts water 50.0 parts Brookfield viscosity Comp A + B addition for non-sagging in the U-profile anti-sag test alter dispersion 1 rpm isopiopanol water 37.5 parts parts 10 rpm STI 1/ _Promaxon Thixotropic Additive.indd /08/09 14:16

4 Stockstability The stock stability of an epoxy mixture, containing PROMAXON as thixotropic agent, is measured during a period of 2 to 3 months. After thixotropising the A-components, the mixtures were stored during a certain period of time, whereafter the antisag effect was determined in U-profiles for the mortars and with the drip test for the coatings. SIKA CHEMIE Sika Chemie: Icosit 255, thixotropised with 4,5 pph PROMAXON D, shows no sag after the two months test period: Product thixotropic agent, needed to obtain a non-sag situation. When stock stabitlity is concerned, the value of sagging is recorded. Anti-sag test in U-profiles In the U-profile anti-sag test high-filled systems for thick layer applications are evaluated. The principle is the same as for the drip test, the result is expressed in pph thixotropic agent needed to obtain a non-sag situation. When stock stability is concerned, the value of the sagging is registered. Therefore half of a U-profile (11*12 mm) is filled with the mixture and is installed vertically with the empty side below in order to create the possibility to sag down. After hardening the sag is evaluated. Icosit 255 Sika Chemie Epoxy coating PROMAXON D 4.5 pph Anti sag test / drip test 1 mm thick coating on glass sheet intitial 0 mm Test methods 1 day 0 mm 1 week 0 mm 2 weeks 0 mm 1 month 0 mm 2 months 0 mm Anti-sag test / drip test In order to compare different thixotropic agents in filled systems, a so-called drip test is carried out. A coating is applied on a glass sheet, using a filmograph of which the clearance is regulated at 1.35 mm, in order to obtain a 1 mm layer. Immediately after application, the glass sheet + coating is installed vertically and the sag is evaluated after hardening. The result is expressed in parts per hundred (pph), calculated on the entire composition of the Typical result of a U-profile anti-sag test General considerations These examples reveal that PROMAXON interacts with the pigments or fillers to form a network. This network produces an increased viscosity at low shear, but also prevents these fillers from settling. The network is broken down by shear forces, which results in a low application viscosity. The network structure is quickly restored when these forces are removed, which prevents the sagging of the applied layer. In high-filled systems only small amounts of PROMAXON need to be added to obtain this effect. Our results show that PROMAXON demonstrates a good and rheological stability during hardening. However, the efficiency of PROMAXON depends upon the whole composition and performance. Therefore the required quantity of PROMAXON must be determined for each system separateley in a case study _Promaxon Thixotropic Additive.indd /08/09 14:16

5 Promat n.v. Kuiermansstraat 1, 1880 Kapelle-op-den-Bos Tel Fax Website _Promaxon Thixotropic Additive.indd 8 19/08/09 14:16