Moldmaking Platinum Cure Silicone Rubber For The Best Reproduction
Molds Of Rapid Prototyped Part
Product description
Platinum cure silicone rubber also known as addition cureRTV
silicone rubber. In a platinum-based silicone cure system, also
called an addition system (because the key reaction-building
polymer is an addition reaction), a hydride- and a vinyl-functional
siloxane polymer react in the presence of a platinum complex
catalyst, creating an ethyl bridge between the two.The reaction has
no byproducts. Such silicone rubbers cure quickly, though the rate
of or even ability to cure is easily inhibited in the presence of
elemental tin, sulfur, and many amine compounds.
Features
High Transparency
High tear and tensile strength
Long shelf life with low shrinkage
Fast mixing (10:1)
Easy processing due to the low viscosity
Applications
Label manufacturing, Molding applications requiring low shrinkage
e.g. toys, jewelry, automotive, rapid prototyping etc.
Technical Properties
| Item No. | MCPLA-H40A | MCPLA-H40B |
| Appearance | Viscous liquid | liquid |
| Color | Transparent | clear |
| Viscosity(at 25℃ ,mPa.s,approx.) | 45000-50000 |
| Specific Gravity(g/cm3,approx.) | 1.08 |
| Proportion(A:B) | 10:1 |
| Max working time(at 25℃ ,minutes) | 60 |
| Demoulding time(at 25,hrs,approx.) | 24 |
| Hardness Shore A(after 24 h) | 40 |
| Tensile Strength(Mpa,after 24 h) | 5.8 |
| Elongation(%) | 350 |
| Tear Strength(N/mm) | 27 |
Processing and Instructions
1. Mixing the two components
According the mixing ration 10:1 weighting A and B, the two
components may be thoroughly mixed either by hand or using a
low-speed electric to minimize the degassing
of bubbles and to avoid any temperature increase. Note: It is also
possible to use a special mixing and dispensing machine for the
silicone components, further information is available upon request.
2. Moulding
The mixture should be degassed preferably at 30 to 50 mbar to
eliminate any entrapped air. If a dispensing machine is used, the
two components are degassed separately prior to mixing. The
silicone mixture expands to 3-4 times of its initial volume and
bubbles rise to the surface. The bubbles progressively disappear
and the mixture returns to its initial volume after 5 to 10
minutes. Wait a few minutes to complete the degassing and then
flash the vacuum. The silicone is ready for pouring, either by
gravity or under low pressure.
Note: Flashing the vacuum once or twice accelerates the degassing.
It is recommended to use a container with a high diameter/height
ratio (3 to 4 times of the initial volume)
3. Polymerisation
The curing may be slowed down at lower temperature or accelerated
by applying heat.
Note: in general contact with certain materials can inhibit the
cross linking of RTV.
Natural rubbers vulcanized with sulfur
RTV silicone compound catalyzed with metal salts, e.g. Tin
compounds
PVC stabilized with tin salts and additives
Epoxy catalyzed with amines
Certain organic solvents, e.g. Ketones, alcohols, etc.
In case of doubt, it is recommended to test the substrate by
applying a small quantity of the mixed silicone on a restricted
area.
Packaging
Part A: 20kg per drum, Part B: 1kg per bottle
Special containers are available are on request.
Storage and shelf life
MC Silicone MCPLA -H Series should be used within 12 months from
the manufacturing date. Beyond this date, MC silicone no longer
guarantees the products confirms with the sales Specification. In
order to preserve best properties it is recommended to follow
strictly the following guild lines:
Store the original packing tightly sealed and at a temperature
below 30 degree Celsius.
Use the product as soon as the packaging has been opened.
