Two shot injection molding / 2K molding | Trelleborg

Two and More Component Solutions with Two Shot Injection Molding 

Increasing cleanliness and hygiene with 2C LSR technology

One of our most outstanding capabilities is the simultaneous injection of LSR in combination with technical plastics, 2C LSR technology. In what is commonly referred to as 2K, 2-shot, multi-component injection molding or co-injection, our LSR experts employ highly advanced and sophisticated tool and process engineering to develop the most innovation solutions, combining two, three or more individual materials into one fully bonded, robust component.

Advantages of 2C LSR Technology:

  • Offers designers much more latitude in design solutions
  • Can integrate multiple components into one fully-bonded solution
  • Single component is more robust than an assembly of individual parts
  • Provides lighter weight components
  • Risks and costs associated with secondary assembly can be avoided
  • Lowers cost by reducing the number of components in the customer’s supply chain
  • Increases cleanliness and hygiene by eliminating dead space and potential bacteria growth in the finished product

Enhanced processing options for more hygienic designs

Trelleborg Healthcare & Medical is at the forefront of tool, process and automation technology for 2C or two shot liquid injection molding. In a fully automated and closed loop system, either a combination of thermoplastic and liquid silicone or two dissimilar grades of liquid silicone are co-molded into a bonded component that offers a wealth of benefits in both assembly and function of the finished product.

A second process option for two component parts, suited for lower production runs and commonly applied by Trelleborg Healthcare & Medical is overmolding. Here, Liquid Silicone Rubber is injected over either a thermoplastic or metal component to create a fully bonded part.

Application Example – Two Component Parts

Medical Safety Valves

Customer: Medical Device Manufacturer

Application: Medical Safety Valves


  • High chemical resistance
  • Withstand CIP chemicals and operate in steam up to +150 °C / +302 °F
  • Compliant with FDA and USP Class VI standards


  • Isolast® perfluoroelastomer bonded to metal consolidating three parts into one

The resulting design of sealing element proved to be highly cost effective. Total cost was reduced by extending replacement intervals, a reduction in the amount of sealing material required and lower assembly costs. The component proved highly effective and the same concept is being used across the customer’s product range.