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| GELNORM® |
 Gel Timer TC Measuring Instruments for Gel Time Determination
Principle
The measurement of the viscosity increase follows in general the DIN 16 945, page 1 point 6.1. According to this standard, the time is determined to reach an agreed upon viscosity limit. This limit is depending on the handling and working process of the resin and shall be determined by producer and user
The automatic GELNORM®-Gel Timer TC for the measurement of gelation time under standardised conditions is easy to use and the results show exceptionally good reproduceability with all reaction resins such as:
• Unsaturated. Polyester resins
• Epoxy resins
• Polyurethane resins
• Acrylic resins
• Silicone resins etc.
The instrument incorporates a switch-off mechanism that responds to pressure: the gelation time limit is reached when the measuring stamper meets a defined reaction force in the reaction resin. As a result of this automatic switch-off system, the size of resin sample employed is not limited. The disposable stamper of stainless steel wire carries out a defined reciprocating movement as soon as the instrument is set in operation and, when the change in viscosity is reached, a built in timer is stopped and the gelation time can be read off
GELNORM® - Gel Timer
An instrument for the automatic determination of the gel time of reaction resins. The design is based on DIN 16 945 and DIN 16 916.
The test with GELNORM - Gel Timer is very easy to perform and gives exceptionally good reproducibility. The automatical measurement can be performed for any reaction resin, for example
• Unsaturated polyester resins
• Epoxy resins
• Polyurethane resins
• Acrylic resins
• Silicone resins
GELNORM GTP for Automatic Gel time determination of Powder coatings
General
Until recently, the accurate determination of the gelation time of powder coatings has represented a considerable challenge to the Industry. In the past, the only method, has been the manual hot plate and string method as per BS 3900:J3, DIN 55’990 and ISO 8130-6., which is time consuming and subject to operator error. Attempts to design an automatic method have been thwarted by the presence of occluded air in samples and the difficulty of obtaining small samples of reproducible particle size.
The new GTP from GELNORM puts an end to these problems. The new instrument carries out automated gel-time measurements under standardized conditions and delivers reproducible results. Furthermore, the measurement elements are disposable, so that there is no waste of time and materials for cleaning
.
Description of the GTP
The general principle of the GELNORM®-GTP is simple, yet ingenious: the powder is melted and cured in a set-up that represents a disposable micro-extruder. The force required for the extrusion is determined and recorded as a function of time which is automatically recorded when the gelation time is reached.
GELNORM®-GTP consists of a control unit and the actual test unit. The former comprises a micro-processor controlled data acquisition system as well as a temperature controller for the thermostatic block which is integrated in the test unit. The temperature range is ambient to 220 0C. The thermostatic block holds a disposable sample cartridge with screw which is linked to a high-precision force sensor. Occluded air is reduced to a minimum by rotating the screw for the first minute of the test.
200 and 250 mg of sample is required, which is similar to the old manual method. The data acquired are shown in real time mode on a liquid crystal display on the front of the control unit.
After reaching the gel point, the gel time is automatically determined and displayed and the experiment is automatically stopped. The sample cartridge containing the cured sample is
disposed of together with the screw. Usually, no cleaning is necessary.
General
Until recently, the accurate determination of the gelation time of powder coatings has represented a considerable challenge to the Industry. In the past, the only method, has been the manual hot plate and string method as per BS 3900:J3, DIN 55’990 and ISO 8130-6., which is time consuming and subject to operator error. Attempts to design an automatic method have been thwarted by the presence of occluded air in samples and the difficulty of obtaining small samples of reproducible particle size.
The new GTP from GELNORM puts an end to these problems. The new instrument carries out automated gel-time measurements under standardized conditions and delivers reproducible results. Furthermore, the measurement elements are disposable, so that there is no waste of time and materials for cleaning
.
Description of the GTP
The general principle of the GELNORM®-GTP is simple, yet ingenious: the powder is melted and cured in a set-up that represents a disposable micro-extruder. The force required for the extrusion is determined and recorded as a function of time which is automatically recorded when the gelation time is reached.
GELNORM®-GTP consists of a control unit and the actual test unit. The former comprises a micro-processor controlled data acquisition system as well as a temperature controller for the thermostatic block which is integrated in the test unit. The temperature range is ambient to 220 0C. The thermostatic block holds a disposable sample cartridge with screw which is linked to a high-precision force sensor. Occluded air is reduced to a minimum by rotating the screw for the first minute of the test.
200 and 250 mg of sample is required, which is similar to the old manual method. The data acquired are shown in real time mode on a liquid crystal display on the front of the control unit.
After reaching the gel point, the gel time is automatically determined and displayed and the experiment is automatically stopped. The sample cartridge containing the cured sample is
disposed of together with the screw. Usually, no cleaning is necessary.
With GELNORM - Gel Timer it is possible to evaluate all factors which influence the gel time of reaction resins such as type and quantity of hardener, accelerator, inhibitor, filler, pigments, as well as temperature and moisture. The instrument is extremely easy to operate and normally needs no maintenance.
GELNORM - RVN Measuring Instrument for Pot Life Determination
An instrument for the automatic determination of the pot life of reaction resins based on the measurement of the relative viscosity. Applications include:
• Unsaturated polyster resins
• Silicone resins
• Epoxy resins
• Polysulfide rubbers
• Polyurethane resins
• Silicone rubbers
• Acrylate resins
GELNORM - RVN can be used for structurally viscous, thixotropic and very slow hardening reaction resins. Highly filled systems such as primers and fillers can be tested with this instrument as well as adhesives.
GELNORM B- Timing Plate according to DIN 16 916
According to DIN 55 990, the gel time of powder coatings is the time required to melt a specimen at a laid down temperature, using a specific test apparatus, and to achieve a gel - like consistency.
For the determination of the gel time of powder coatings, our Heating Block PL in accordance with the German Standard DIN 55 990 (ref. 30.45) with a spherical depression (mould) is used.
The temperature is precisely controlled with our temperature controller TC-2 (ref. 70.01).
GELNORM B- Timing Plate according to DIN 16 916
B - time determination on the B-Timing Plate provides information on the curing of resins capable of heat hardeniong, namely the reaction time at a given temperature, after which resins (solid, liquid or solvent - containing resins of a know concentration) change to the B - stage.
The temperature is precisely controlld with the TC-2 temperature controller.
GELNORM - DE Measuring Instrument for Curing Process
A novel measuring instrument for establishing the curing reaction of two-component reaction resin systems (thermoset resins). The new instrument is based on the determination of a function of electical conductivity as well as the capacitance of a resin sample. This electrical function enables to trace the curing process over the whole regime of the chemical reaction.
Fig. 11 shows that the electric function as determined with GELNORM - DE is inversely proportional to the viscosity of a polymer sample. Hence, the instrument provides new possibilities to investigate the curing reaction of reaction resins such as:
• Epoxy resin
• Silicone rubbers
• Polyurethane resins
• Polysulphide rubbers
• Polyester resins
The electrical measuring technique offers numerous advantages compared to the various mechanical methods. In contrast to the conventional rheological approach (based e.g. on rotation- or shear viscosimeters), the polymer sample is in no way and at no time subject to any kind of mechanical forces. Thus, any kind of mechanical distortion of the polymer structure during the curing can be excluded
GELNORM® - MED
For medical applications eg
Gelation evaluation of bone cement is a measuring instrument for the hard setting sequence of two component systems, which either have a high initial viscosity or in which the viscosity rises to very high values during the hard setting process. The instrument is also suitable for systems that have a filler type starting viscosity: the viscosity of such systems cannot be measured with conventional rotational viscometers.
Description of Equipment
GELNORM®-Med consists of a compact control unit with stand, in which the measuring equipment is incorporated. At the heart of this measuring unit is a force sensor, on the end of which the test body is attached. This is dipped into the reactive resin based substance at a defined speed, e.g. 0.01mm/sec. In this process, the increasing viscosity is displayed as a force, measured in Newton, against time
Provision is also made to measure, simultaneously with the force, the change in temperature in the resin specimen, and to record this.
The measuring data is displayed on a PC using software included in the scope of supply, and this can be further evaluated using MS-Excel®. The parameters needed for the measurement (speed, force range, countdown, data name, etc.) are preset directly on the PC before measurement commences.
When measurement has been completed the lower part of the test body is left in the reaction resin and is thrown away with the resin specimen. The part is not cleaned.
Measuring Procedure
The reaction resin mixture is prepared in a beaker or other receptacle suitable for the measurement. The start button on the front of the GELNORM®-Med is then pressed. Initially, a countdown sequence (e.g. 60 seconds, – freely selectable in steps from 1 second to max. 300 seconds) is run off to allow time for the substance to be mixed and placed ready underneath the measuring unit. The test body is then lowered into the resin specimen under the control of the LIFT/SINK push button.
At the end of the countdown period, the test body automatically enters the reaction resin mixture at the preset speed. Simultaneously, the data (viscosity and possibly temperature) is transmitted online to a computer via an RS 232-interface, and is displayed. The measuring data is stored and is then available in an MS-Excel®-file, allowing further evaluation.
Technical Data
Operating voltage: 230V/50Hz or 110V/60Hz
Force measurement: ± 50N
Feed speed: 0,01 – 0,1mm/sec
Temperature measurement: Pt-100 or NiCrNi 0 – 220°C
Operating computer: MS-Windows 95® or higher
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