Handling & logistics
TROGAMID® compounds are generally supplied as natural-colored granules in moisture-proof bags with a net content of 25 kg. With prior arrangement, TROGAMID® compounds can also be supplied in big bags with a capacity of 1,000 kg. For sufficiently large orders special colors can be provided on request. The shelf life is virtually unlimited at room temperature provided that the packaging is undamaged.
TROGAMID® compounds are supplied in moisture-proof packaging predried to a water content less than 0.1 %. Further drying is not imperative if the packaging is not damaged. Before the packaging is opened, its contents should be allowed to reach ambient temperature, in order to avoid moisture condensing on the cold granules.
Under certain conditions—if, for example, the retention time in the feed hopper is exceedingly high or the material for processing is from packages that have already been opened—the granules should be pre-dried in a dry-air dryer at a temperature of 80–90°C over a period of 8 to 12 hours. Drying cabinets with a fresh air supply are not suitable. In certain cases, such as the extrusion of thick-walled profiles, and injection molding of thick-walled and optical components or of components of high surface quality, the granules should be pre-dried at any rate to prevent moisture streaks or uneven surfaces from forming. The melt should form a highly transparent strand free of bubbles or streaks, to obtain molded parts that are visually and mechanically perfect.
Incompatibility with other thermoplastics
TROGAMID® compounds are not compatible with most other plastics. Even small quantities of other plastics contaminating TROGAMID® resins lead to clouding of the melt and the finished parts. Before work is started, therefore, the plastification units of the processing machine and all other melt channels should be very carefully cleaned with the usual cleaning agents or with prepared TROGAMID® sprue or start-up waste.
Use of regrind
Due to the hygroscopic properties immediate reprocessing of TROGAMID® scrap is recommended. The regrind material must be free from foreign matter and dirt particles, the moisture content should be below 0.1 wt.-%. Small quantities of other polymers, even other polyamides except of the same TROGAMID® grade will cause clouding of the corresponding molded parts. If an immediate reprocessing of the scrap is not possible, sprues or defective parts should be grinded and stored in moisture-proof bags straightaway. A careful drying before reuse is necessary.
The quantity of regrind added to virgin material is generally dependent on the required part properties and must therefore be determined by tests on the ready molded part. If the use of regrind is allowed by the requirements and specifications of the enduser, additions of up to 25 wt.-% regrind are possible.
TROGAMID® is best colored with color concentrates based on identical TROGAMID® resins. Dry coloring by tumbling with finely powdered pigments is another possibility but it is inconvenient, as pneumatic conveying is impossible. The use of color pastes or color concentrates having a "neutral" (e.g. PE) base can lead to incompatibility with TROGAMID® and hence to poor part properties (poor weld line strength or low transparency due to clouding). Therefore, prior testing of compatibility is absolutely necessary.