Technical Resources - Simethicone
Jun 25, 2012
Working with High Consistency Rubbers
A high consistency rubber, or HCR, consists of a high molecular weight polymer combined with reinforcing filler to produce a material that can be molded, extruded, or calendered into a useful end product. An HCR has the consistency of clay when uncured and is primarily formulated in a one- or two-part system (peroxide and platinum catalysts respectively). Known for high mechanical strength, HCRs are also sometimes referred to as high tear rubbers or high tear elastomers (HTRs or HTEs). This application note will cover potential applications for HCRs, typical properties, cure chemistries, and processing HCRs.
Feb 27, 2012
Optically Clear Materials for Healthcare Applications
NuSil’s optically clear elastomers for healthcare applications are all
highly processed materials that crosslink via an addition cure
mechanism. Optically clear, or transparent, means that light waves are
partially reflected and partially refracted (transmitted through the
material). Refractive index (RI) is defined as the ratio of the velocity of
light in a vacuum to the velocity of light in a material1. The high
refractive indexes of the products listed below indicate that they are
highly responsive to light. These restricted healthcare materials meet
all USP Class VI and many ISO-10993 test requirements for
biocompatibility. For more information on NuSil’s restricted and
unrestricted materials, please visit www.nusil.com or refer to the
Dec 9, 2011
Adhesion and Silicone Adhesives
Most silicone adhesives are made of silica-filled silicone polymers that cure in place by crosslinking. The overall mechanical strength is known as cohesive strength. The strongest bonds are those which occur between atoms from chemical bonding; however, adhesion is not limited to chemical bonding. Conversely, materials can have the ability to form a strong “bond” when brought into contact with another surface for a short time (seconds) under light pressure. This short-term, pressure-induced attachment is known as tack2. Tack and adhesion are influenced by how a force (and how much of it) is applied to the bond, as well as the bond thickness (thinner can be better)1.
Mar 4, 2011
Moisture Permeability of Silicone Systems-Case Study 2
The purpose of this Case Study is to further clarify the relationship between Water Vapor Transmission Rates (WVTR) and select silicones. This study will assist with product selection when moisture permeability is of interest for specific applications. An analysis of how various fillers and durometers influence WVTR is provided.
Dec 1, 2010
A Guide to Silicone Dispersions- Strategies for Processing and Troubleshooting
This application note will summarize important properties and characteristics of dispersions, present guidelines for applying a dispersion and offer suggestions for troubleshooting.
Oct 21, 2010
Production Methods for Manufacturing Chewable Tablets-Oral Form
Simethicone has been used for many years as a pharmaceutical antifoam to treat discomfort associated with gas buildup in the stomach or the large intestine. Simethicone works by causing small gas bubbles to coalesce into larger bubbles, making them easier to pass, by either belching or flatulence. Simethicone does not keep gas from forming, but rather allows a person to easily pass the built-up gases. This paper will address the production methods for manufacturing chewable tablets - oral form.
May 28, 2010
Working with Liquid Silicone Rubbers - Best Practices from Prototype to Large Scale Production
This whitepaper characterizes Liquid Silicone Rubbers (LSRs) and their typical properties and gives guidelines for obtaining the best results from initial design to prototyping to full scale production
Dec 16, 2009
Mixing and De airing Addition Cure Silicones
Silicone and air mixtures are very complex and dynamic systems, however this article’s purpose is not to discuss fluid dynamics and laminar flow, but rather the basics of how air can be introduced into a system, common methods of mixing and de-airing, and packaging options when specialized mixing and dispensing equipment is not available.
Jul 21, 2009
Application and Storage Recommendations for NuSil’s Primers
Adhesion is a critical property for numerous applications involving silicone materials. Silicone primers
are often used to improve adhesion between silicones and various substrates. The proper handling and
application of silicone primers can enhance the overall strength and consistency of bonds. This document outlines the procedures that are recommended for best bonding results.
Jun 24, 2009
Moisture Permeability of Silicone Systems- Case Study #1
The healthcare, electronics and aerospace industries use silicone elastomers and adhesives in a broad range of applications. Humidity control is an important parameter of concern for these applications. For instance, wound dressings must “breathe” similar to our skin to accelerate the healing process. In other applications moisture permeability can cause premature failure due to corrosion of electronic components or other means. An example would be moisture sensitive fillers and humid environments can alter the performance of the functional fillers. In Light Emitting Diodes (LEDs), phosphors added to the silicone encapsulant to make white light may absorb moisture over time, which could alter the light output of the LED.