Active content % Ash residue < 0.5 % ( as Na 2 O) Viscosity Brookfield RVT 20 rpm (mpa s) Tg + 4 C ph 7 9

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1 RESICEL E/50 N Binder and anti-cracks agent for casting slip Chemical composition: Emulsion based on a non-ionic acrylic copolymer. Chemical and Physical characteristics: Appearance at 20 C White emulsion Density (g/l) 1030 approx. Active content % Ash residue < 0.5 % ( as Na 2 O) Viscosity Brookfield RVT 20 rpm (mpa s) 200 c.a. Tg + 4 C ph 7 9 Properties and application: RESICEL E/50 N reduces the number of cracks during consolidation and drying of ceramics shaped by slip casting. Slip casting defects, like breaking and cracking, occur when the deformation strengths, due to uneven shrinkage or to a mechanical shock, overwhelms the mechanical resistance of the ceramic piece. The deformation strengths are stronger in the first part of drying, when shrinkage is higher. These considerations lead us to develop an additive, for slip casting bodies, able to increase the mechanical strength and gives a certain elasticity to the cast body, in order to delay cracks formation as much as possible. By this way it is possible to reduce cracks number, as after a certain time the deformation strengths linked to shrinkage become weaker, and they are not able anymore to overwhelm the mechanical resistance of the cast piece. Many tests were run during the developing of Resicel E/50 N, to find the more suitable product for the above mentioned purposes. The main tests were performed with different slips and additives in the following way : 1) Additives are added by stirring to the slip. 2) Measuring of main parameters of the slip. 3) A plaster cylinder-cone is immersed into the slip for a fixed time, then the cone is pulled out and weighted. Fig.1 shows the appearance of the plaster cylinder-cone wearing the ring of body settled by slip casting. 4) Thickness and humidity of the layer are measured. 5) The specimen is dried in a controlled environment, while a camera connected to a computer takes a picture every 3 minutes; in such a way it is possible to determine exactly when shrinkage causes the breakage of the ring. Usually several specimens (using different additives) were controlled together for comparative tests. (Ts358 Jul./04) PAGE 1 OF 5

2 6) The broken ring is detached by the plaster, then dried and weighted. 7) Data are registered and compared (always with the ones of a sample made by the same slip without the additive) (see table A and B). Fig. 1 The plaster cylinder-cone wearing the ring of body settled by slip casting. A typical sequence obtained in the tests is shown in the following pictures; checking all the pictures recorded by the computer, you can get the precise sequence and timing of crack formation in the specimens. (Ts358 Jul./04) PAGE 2 OF 5

3 Specimen 8 breaks after 14 hours Specimen 7 breaks after 14.3 hours (Ts358 Jul./04) PAGE 3 OF 5

4 After 16.3 hours specimen 3 cracks too. Every test was always run also on a specimen without additives for reference. The followings tables (A and B) show the results got with two different slips, treated with an addition of 0.06% of Resicel E/50 N. The delaying of the cracking time is not very long but clearly evident, respectively of 19 % and 9 %, while thixotropy and casting rate are practically unchanged. Doubling the dosage ( %) casting rate increase, but cracking time is less delayed. Slip 1 Reference Resicel E/50 N Additive on dry material (%) Gallenkamp viscosity Gallenkamp thixotropy ( 5') Weight just cast Moisture just cast (%) Weight after 24 hours Moisture after 24 hours (%) Dry weight Increase dry weight (%) Thickness (mm) Increase thickness (%) Cracking time Delay cracking time (%) - 19 % (Ts358 Jul./04) PAGE 4 OF 5

5 Table B - Slip 2 Reference Resicel E/50 N Additive on dry material (%) Gallenkamp viscosity Gallenkamp thixotropy ( 5') Weight just cast Moisture just cast (%) Weight after 24 hours Moisture after 24 hours (%) Dry weight Increase dry weight (%) Thickness (mm) Increase thickness (%) - 3 Cracking time Delay cracking time (%) Industrial comparative tests run using Resicel E/50 N at low dosage ( %) have shown that RESICEL E/50 N doesn t eliminate completely cracks, but it gives an evident and sensible reductions of culls due to cracks at low cost. Advantages are usually more evident in the production of large and complicated-shaped items. Instruction for use: RESICEL E/50 N is easily dispersible and it is usually added in slow stirring storage tanks. It is also possible to add RESICEL E/50 N in the tanks serving directly the various casting benches or pressure casting machines (heated tanks). As any additive added to a slip RESICEL E/50 N might modify rheology and casting rate; changes of these two factors must be taken into consideration. If viscosity and/or thixotropy become too high, adding a slight amount of deflocculant (we suggest polyacrilates - i.e. Reotan) is usually sufficient to come back to suitable casting parameters. Dosage: Dosages: from 0.04% up to 0.1 % computed on the solid content of the slip. Storage and packaging RESICEL E/50 N is stable to prolonged storage under condition where extreme temperatures do not occur. Do not store at temperatures above 40 C. The product suffers frost. The product is stable for at least 6 months in the recommended storing condition. Packaging: 125 kg drums or 1000 kg tanks. Safety: RESICEL E/50 N presents no hazard for handling and storage, and so no warnings or labels are required. Nevertheless it is necessary to remember that improper use of chemicals and the absence of basic practices of industrial hygiene can be harmful to health and environment. Detailed health and safety information can be found in our safety data sheet, available according to ECC Directive. (Ts358 Jul./04) PAGE 5 OF 5