Knowde Enhanced TDS
Identification & Functionality
- Chemical Family
- Polymer Name
- Technologies
- Product Families
Features & Benefits
- Product Highlights
- Pre-catalyzed, high consistency elastomer
- High durometer
- Strained through a 400-mesh screen (minimum)
Applications & Uses
- Markets
- Plastics & Elastomers End Uses
- Plastics & Elastomers Processing Methods
- Applications
- For a wide variety of fabrication techniques for the healthcare industry including: molding, calendering and extruding
- Instructions for Use
In general, freshly softened elastomers have better processing characteristics, therefore milling to a smooth consistency before use is advised, regardless of the age of the elastomer. After the peroxide has been added, it is important to minimize heating of the material when milling to prevent premature partial curing. Maintain the temperature of the elastomer at less than 43°C (109°F) during milling.
The amount of peroxide required to cure the product is dependent on the type used and the chosen fabrication technique. The most practical way to establish the proper amount of catalyst is for the user to experiment with the elastomer and equipment that will be used for production. Several organic peroxides are suitable for vulcanizing this product. Contact NuSil Technology for information on catalyst selection.
Molding
This product can be formed into cured configurations by compression, transfer or injection molding processes. Molding cycle times are dependent on the mold temperature and crosssectional thickness of the part. It is best to use highly polished, chrome-plated or stainless steel molds for these operations. Other polished metals will normally require release agents to prevent sticking. If using release agents, clean the molded parts prior to use.
Calendering
Calender the elastomer into sheeting with or without reinforcement. Make sheeting by calendering onto a laminate such as Mylar™ or polyethylene, for vulcanized and unvulcanized sheeting, respectively. If using Mylar™, strip off the Mylar™ after vulcanization while the sheet is still hot. If using polyethylene, strip off the polyethylene before vulcanization. Long lengths of Mylar™ laminated sheeting can be calendered on a core and vulcanized in a hot air oven or steam autoclave.
Extrusion
For maximum uniformity, re-soften the elastomer on a two-roll mill at time of use. Extrude the elastomer through an unheated die to make rod, tubing and coated wire. Vulcanize after extrusion by passing the material through a horizontal or vertical heated chamber. The residence time will vary based on the temperature of the chamber and the size/thickness of the extrusion.
Post-curing
Depending on the peroxide catalyst used a post-cure may be required. The post-cure serves two distinct purposes. Postcuring removes the volatile components and other residuals generated from the decomposition of the peroxide during vulcanization. Post-curing also stabilizes and enhances the physical properties of the elastomers. Accomplish post-curing by heating the vulcanized material in a hot air circulating oven to a predetermined temperature for the required length of time. The oven must have an exhaust system of sufficient capacity to prevent volatiles from reaching an explosive level. The exhaust system should be vented so as to prevent worker exposure. The time required for post-curing at a given temperature depends upon the rate at which the volatiles can escape from the elastomer, which in turn depends upon the thickness of the part, the exposed surface area and the oven loading.
Properties
- Appearance
- Translucent
- Typical Properties
- Cured Properties
| Value | Units | Test Method / Conditions | |
| Durometer Type A | 70.0 | — | — |
| Tensile | 1,300 (8.97 ) | psi (MPa) | — |
| Elongat ion | 450.0 | % | — |
| Tear | 130 (22.93 ) | ppi (kN/m) | — |
| Mix Rat io | 1 PART | — | — |
| Specific Gravity | 1.21 | — | — |
| Stress at Strain 200 % | 500 (3.45) | psi (MPa) | — |
| Value | Units | Test Method / Conditions | |
| Cure at 116 °C | 5.0 | minutes | — |
| Cure System | Peroxide | — | — |
| Post Cure at 249°C | 2.0 | hours | — |
Packaging & Availability
- Country Availability
- Regional Availability
Storage & Handling
- Storage and Handling
Handling Precautions
During vulcanization, oven-curing, and post-curing of silicones catalyzed with peroxide, residual volatile byproducts of vulcanization may be released in small amounts. Studies have been conducted and conclude that minimal to no PCBs are released during cure; however, these vapors, if present, may be harmful and appropriate precautions should be taken. Work areas must be well ventilated, and workers should avoid inhalation of vapors. Review the Material Safety Data Sheets for specific information.