Remix each of the two components (parts A and B) every time before using.
1. Mixing of the two components
For each product, mix the two parts BLUESIL RTV A and BLUESIL RTV B according to the mix ratio A : B = 10 : 1.
In the case of BLUESIL RTV 3131 A&B and RTV 3132 A&B, because of their short working time it is recommended to mix and dispense the product by means of a static mixer, after degassing the two parts separately (see § 2. Degassing below).
For BLUESIL RTV 3130 A&B, and RTV 3131 SC A&B, the two components may be intimately mixed either by hand or by means of a low-speed electric or pneumatic mixer to minimize the introduction of air into the mixture.
After mixing BLUESIL RTV 3130 A&B, it is recommended to eliminate entrapped air. If the mixing is done with the help of a machine and a static mixer, like recommended for BLUESIL RTV 3131 A&B and RTV 3132 A&B, both parts are degassed before mixing.
The degassing of the mixed product or of the two separated parts occurs under a vacuum of 30 to 50 mbar. Under vacuum, the product expands 3 to 4 times its initial volume and forms bubbles on its surface. These bubbles will disappear gradually and the mixture will sink back down to its initial volume within 5 minutes. Release the vacuum and repeat the operation a few minutes later.
Remark: release the vacuum several times imes the degassing. For easier degassing only fill a recipient to 1/3 of its height.
The best curing conditions are at 23°C. When using the products at higher temperatures, the pot life is shorter and the setting rate faster. As opposed to this, lower temperatures increase the pot life and decrease the setting rate.
Room temperature curing assures the lowest possible shrinkage, if accelerated cure is desired, mild heat should be preferred. To minimize shrinkage the elastomer should be cured at maximum temperature of 60°C, higher temperatures might cause higher shrinkage.
At 23°C, the cured silicone can be demoulded after the time indicated as "demolding time"" (see §2.Polymerization, pag.1). In order to achieve the best possible performance levels from the pads, it is preferable to wait for 24 hours before using them.
Be aware that contact with certain materials can inhibit the curing of this RTV:
- Natural rubbers vulcanized with sulphur
- Polycondensation RTV catalysed with metal salts
- PVC stabilizing agents
- Amine cured epoxies
- Sulphur containing clays
If doubts exist it is recommendable to run a quick test with a small quantity of material in order to assess compatibility. Take duly note that cross contamination due to not well cleaned tools or devices is frequently the main cause of inhibition. The best way is to use only dedicated gear when processing polyaddition RTVs and not to exchange drum covers.
4. Processing aids
4.1 Adhesion promoters ("primers")
In order to achieve adhesion of BLUESIL RTV 3130 A&B, RTV 3131 A&B, RTV 3131 SC A&B or RTV 3132 A&B on the pad support, it is recommended to prime the support with an adhesion promoter. Bluestar Silicones recommends the use of both primer PM 820 and primer PM 811 A&B according to the instructions next page.
|||PRIMER PM 811 A&B|
|Substrate||Metal (steel, aluminum), plastic (polyester), reinforced resins |
|Pot-life A+B||N.a. (monocomponent)||> 3 days|
|Usage level||Very thin layer (30÷60 g/m2) |
Application of PM 820
Wait 30 minutes
Application of PM 811
Wait 30 minutes up to 7 days
Application of RTV-2 Silicone
|Application by||Spray, brush, cloth|
For more detailed information, please refer to the Technical Data Sheets of the Primers.
4.2 Crosslinking accelerator / retardant
Should it be desired to change the polymerization time of BLUESIL RTV 3130 A&B, RTV 3131 A&B, RTV 3131 SC A&B, or RTV 3132 A&B products, following additives allow a customization by increasing the pot-life (retarder PA40) or by shortening it (accelerator PA39).
Information on their use is shown in the table below:
|||ACCELERATOR PA39||RETARDER PA40|
|Usage level||0.1 ÷ 5 %||0.1 ÷ 1 %|
|Use||Mix PA39 into Pt catalyst ||Mix PA40 into base part|
|Suggested for||RTV 3130, RTV 3131 SC||RTV 3131, RTV 3132|
As an indication, the effects of the two additives on the pot-life are shown in the following graphs.
4.3 Oil dilution
The hardness of both BLUESIL RTV 3130 A&B, RTV 3131 A&B, RTV 3131 SC A&B, and RTV 3132 A&B can be adjusted by means of a non reactive silicone oil, that plasticizing the silicone network lowers the material hardness. BLUESTAR SILICONES offers the low viscosity silicone oil BLUESIL FLD 47V50, that can be added to the BLUESIL RTV A&B products.
|BLUESIL RTV 3132 B may be stored at a temperature below 40 °C/ 104 °F for up to 6 months from its date of manufacturing.||Please consult the Safety Data Sheet of this product.|
BLUESIL RTV 3132 B
The BLUESIL RTV 3130 A&B, RTV 3131 A&B and RTV 3132 A&B are two component silicone elastomers which cure at room temperature by a polyaddition reaction.
This reaction can be accelerated by heat.
2 Part RTV
- High purity products particularly designed for printing pads production.
- Outstanding mechanical properties.
- Excellent solvent resistance.
- Adjustable hardness by diluting with silicone oils.
- Antistatic properties for BLUESIL RTV 3132 A&B.
- Possibility to choose between longer (BLUESIL RTV 3130 A&B) or shorter working time (BLUESIL RTV 3131 A&B).
These products are specifically formulated for the production of printing pads.
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