Flexible mould making silicones

Jon Lawson

Flexible moulding is a very popular go-to system across many industries when faced with a part reproduction application.

It is more cost effective than 3D Printing for small runs and a great alternative to solid mould processes such a liquid injection moulding or resin transfer moulding.

The rapid prototyping Industry has adopted flexible moulding for a wide range of applications including automotive casting, aviation and consumer electronics.

This process is also making an impact with large volume production tasks, architectural element production, and composite manufacturing and even with art reproduction and restoration projects.

UK- based distributor Techsil is launching three new flexible mould making grades from Momentive Performance Materials.

These new products will join RTV664, an addition cure silicone system that can be used in compliance with US FDA food grade regulations.

Momentive’s comprehensive mould making range includes 21 addition and eight condensation cure silicones for prototyping applications and making moulds for complex precision parts.

The new flexible mould making grades are:

TSE3478T is a two-part addition cure silicone; this oil bleed system is easy to degas, has a handy 10:1 mix ratio and works to standard cure conditions.

The product cures to a translucent rubber with a tensile strength of 6.0MPa, hardness of 40 (Type A), 380% elongation and extremely low shrinkage1.

TSE3480T is a two-part addition cure silicone; a non-oil bleed system that offers improved mould life.

As with TSE3478T, this system has a handy 10:1 mix ratio and works to standard cure conditions. The product cures to a translucent rubber with a tensile strength of 6.0MPa, hardness of 37 (Type A), 380% elongation and extremely low shrinkage1.  

RTV664 is a two-part addition cure silicone; it is a non-oil bleed system with a high cured shore hardness and can be used in compliance with US FDA regulations. This product has a shorter work life and de-mould time at room temperature than the new materials, but which cannot be further shortened with the addition of heat. RTV664 cures to a 62 Shore A, light blue rubber with very good tensile strength (6.4 MPa), 245% elongation and very low linear shrinkage1.

RTV7888-20 is a two-part condensation cure silicone; this non-oil bleed system is best suited for soft mould making.

Again, it has a handy 10:1 mix ratio and works to standard cure conditions; however unlike TSE3478T & TSE3480T, RTV7888-20’s work life and demould time cannot be shortened with heat. The product cures to a soft 20 Shore A light pink rubber with a tensile strength of 3.4MPa, 350% elongation and low shrinkage1.

1 These typical properties are average data and are not to be used as or to develop specifications.