Product description: Polyurethane E 4245 is a two component, solvent free, high modulus, polyurethane elastomer. It provides excellent elasticity and high tear resistance properties with minimum shrinkage. Cures by reaction (cross linking) of the two components even at very low temperatures. The Polistep Polyurethane E 4245 is supplied in yellowish-transparent color. Mixing Ratio (A : B) = 100:100 by weight. Uses: Consumption The Polistep polyurethane E 4245 is a specialized elastomeric resin for: • production of molds for use in concrete and gypsum objects production. • production of molds for use in resin objects production. • production of elastic objects. • filling / casting applications.
Advantages: · Solvent free · Shore A 45-50 · Cold curing · Minimum shrinkage · High tear strength · High impact strength · Chemical resistant
Application: Preparation of Prototype Object Before casting, check that the surface or object to be copied (creation of mold) is free of any trace of moisture (Maximum surface moisture content should not exceed 4%). Moist gypsum and clay prototype objects need to be placed in an oven, to remove all humidity. If the object to be copied is porous (clay, gypsum, concrete, wood, etc.), it needs to be pretreated by sealing all pores with the Polistep E 495 resin/varnish (find it in Polistep assortment). Depending on the porosity of the surface/object a second layer of the E 495 resin/varnish might be needed. Before the application of the Polistep polyurethane E 4245, the prepared object has to be coated with a suitable liquid-applied mold release agent to avoid bonding with the prototype object.
Mixing: Stir Polistep E 4245 Component A well before using. Stir Polistep E 4245 Component B well before using. Polistep polyurethane E 4245 Component A and Component B should be mixed by low-speed mechanical stirrer, according to the indicated mixing ratio in this technical data sheet, for about 2 min. The mixing of the components has to be affected very thoroughly, especially on the walls and bottom of the pail, until the mixture becomes fully homogeneous. After the initial mixing of the two components, transfer the mixture into a clean container and mix again for 1min, in order to make sure that the components have been mixed thoroughly. Apply polyurethane E 4245 resin with a brush on the surface/object to be copied, to avoid entrapped air pockets. After 15-30 min create the mold by filling up with Polistep polyurethane E4245 resin. RECOMMENDATION: Use a suitable sized vacuum apparatus (-1 bar), to remove entrapped air bubbles from the polyurethane E 4245 A+B mixture, directly after mixing and before casting.
Use of the Mold: When the mold, created out of the Polistep polyurethane E 4245 resin, is to be used for gypsum/concrete objects production, please ensure that the mold is fully coated on the inside with the polyurethane E 498 liquid-applied mold release agent, in order for the parts to be removed easily. When the mold is to be used for resin objects production, please ensure that the mold is fully coated on the inside with the liquid-applied mold release agent, in order for the parts to be removed easily.