ZA 22 – Addition-cure RTV silicone

Silicone RTV ZA 22 Zhermack for flexible moulds and reproduction details of 2 microns

ANNEX 22 Zhermack is a silicone rubber liquid RTV2, two-component, based on addition, intended to make Flexible moulds for fine detail models and complex geometry.

It is one of the most versatile and used silicones in the Best TOOLS range, due to the balanced combination of flexibility, mechanical strength, fluidity and dimensional stability.

One of the most important advantages of ZA 22 is the ability to reproduce details up to 2 microns. This characteristic recommends it for patterns where texture, edges, engravings, inscriptions and very small details must be transferred precisely to the mould.

Best TOOLS recommends ZA 22 as general silicone for making the molds used for casting of plaster, cement, Acrylic One, polyurethane resins Multicast, wax, soap and other compatible materialsThe final choice is made according to the geometry of the model and the estimated number of reproductions.

Extremely fine reproduction of details - up to 2 microns

Zhermack declared for ZA 22 a reproduction capacity of 2 microns.

This is one of the characteristics that differentiates the product in the applications where the original model contains textures, engravings, inscriptions, reliefs or very fine geometric elements.

In practice, this precision allows the production of molds that take over very faithfully the surface of the original model, provided that the model is properly prepared and the cast of the silicone is properly achieved.

Dimensional stability - molds that can be stored for subsequent uses

The dimensional variation declared by Zhermack after 24 hours is only -0,05%.

This dimensional stability is very important when the same mould should be used again after long storage periods.

In Best TOOLS practice, such moulds are sometimes called "library moulds": the mould is made, used, then stored for future projects, keeping geometry and initial dimensions very well.

This is particularly important for the reproduction of ornaments, technical models, decorative parts or elements that must be remade with the same geometry.

Recommended applications

Plaster moulds

ZA 22 is one of the main recommendations for Best TOOLS molds for ironing plaster.

The combination of flexibility, laceration resistance and dimensional stability allows repeated use of the mould, including for decorative models with details and reliefs.

mould for cement and mineral materials

ZA 22 is also commonly used to make Flexible moulds for cement and other mineral materials.

Flexibility of the mould facilitates the demoulding of decorative elements, ornaments and relief shapes.

mould for Acrylic One

ZA 22 is successfully used by Best TOOLS clients to pour the system Acrylic One.

For Acrylic One applications, a correctly designed and executed ZA 22 mould can offer a very large number of usage cycles.

Multicast polyurethane resins

ZA 22 is commonly used with Multicast polyurethane resins marketed by Best TOOLS.

However, polyurethane resins require the surface of the mould different from plaster, cement or Acrylic One. During repeated use, resin can gradually penetrate the Silicone surface microstructure, which contributes over time to the degradation of the mould.

For this reason, the number of reproductions obtained with polyurethane resins is generally lower than with mineral materials or Acrylic One.

Cereal moulds and soap

ZA 22 can also be used to make molds for wax and soap.

For very delicate parts or applications where a softer mould is required, Best TOOLS can recommend a silicone with lower Shore A hardness, such as ZA 12 LT. ZA 22, however, remains a versatile solution when a balance is sought between flexibility and mechanical strength.

Modelism and molds for complex geometry

Zhermack indicates ZA 22 for mould-making and model-makingdue to the precise reproduction, dimensional stability and mechanical resistance.

It is suitable for models with small retention, reliefs and complex geometry that require mould deformation during demoulding.

Decorative ceramic

ZA 22 is recommended by the manufacturer and decorative ceramicswhere the precision of reproduction and mechanical strength are important criteria.

Practical advantages ZA 22

Reproduction up to 2 microns
It allows very precise copying of the textures, reliefs, engravings and fine details of the model.

Balanced hardness - 21 ± 2 Shore A
It offers a very good compromise between the flexibility needed to emulate and the mechanical strength of the mould.

High tensile strength
The declared value is over 20 ± 1 N / mm, the important feature for the molds used repeatedly.

Landing at break 380 ± 20%
Allows the mould to deform during the demoulding of complex models.

Dimensional variation of only -0.05%
It contributes to maintaining the geometry of the mould and to the repeatability of the reproduced parts.

High fluidity
Helps the silicone penetrate into fine details and cavities of the model.

Very good anti-adhesion effect
The manufacturer mentions an excellent anti-stick effect of vulcanized silicone.

Aging resistance
Zhermack mentions stability in time and resistance to aging and high temperatures.

Main technical characteristics

• Type: Silicone rubber addition-cure RTV2, two-component
• Mixing ratio: 1:1
• Vascosity of the mixture: 4000 ± 300 cP
• Density: 1,15 g / cc
• Mixing time at 23 ° C: about 1 minute
• Working time at 23 ° C: 14 - 17 minutes
• curing time at 23 ° C: approximately 60 minutes
• hard after 24 hours: 21 ± 2 Shore A
• Traction resistance: 4.0 ± 0.2 N / mm ²
• Landing at break: 380 ± 20%
• Resistance to laceration: > 20 ± 1 N / mm
• Reproduction of details: 2 microns
• Dimensional variation after 24 hours: -0,05%

Temperature influence on working time

Temperature directly influences the reaction velocity of ZA 22.

Temperature more than 23 ° CWork time and curing time are reduced.

Temperature less than 23 ° C, working time and curing time increase.

Zhermack mentions, as an example, that at about 40 ° C the working time can be reduced by approximately half, and at very low temperatures the times can increase considerably.

For this reason, for repeatable results it is recommended to process the material under controlled temperature conditions.

Complete an additional silicone mould

If the material originally prepared is not sufficient to complete the mould, Zhermack indicates the possibility of letting the first silicone become semi-reinforced and then add additional material.

The addition should be made within the range indicated by the manufacturer, up to 24 hours after the first casting has been cured.

The newly adhered material can bind to the silicone already cured without altering the final result.

Compatibility

According to Zhermack documentation, ZA 22 is compatible with:

• gypsum;
• coatings;
• Polyurethane resins;
• Acrylic resins.

In Best TOOLS practice, ZA 22 is commonly used with plaster, cement, Acrylic One and Multicast polyurethane resins.

Best TOOLS Available Packages

ZA 22 is marketed by Best TOOLS as a complete kit, base + catalyst:

• Kit 2 kg
• Kit 10 kg
• Kit 50 kg

The quantity indicated is the total amount of material received by the customer.

Recommended complementary products

• Polyurethane resin Multicast - frequently used with ZA 22 moulds to pour rigid parts.
• Acrylic One - system commonly used in ZA 22 moulds for decorative and technical elements.
• Moulding agent - recommended especially for applications with resins and repeated cycles.
• Vacuum room and vacuum pump - useful for reducing the air in silicone.
• Precision scale - for proper compliance with ratio 1: 1.
• Mixed containers and spatulas - for dosing and mixing of the two components.
• Sulphur-free modeling plastic - useful for preparing models and making certain types of moulds.

Common questions about ZA 22

Conclusion

ANNEX 22 Zhermack RTV2 silicone is a balanced and versatile addition, designed for flexible moulds with high precision and good mechanical strength.

Capacity to reproduce details up to 2 microns level, dimensional change of only -0,05%, hardness of 21 ± 2 Shore A and high laceration resistance make it suitable for a very wide range of professional applications.

For Best TOOLS clients, ZA 22 represents one of the main choices for molds intended ipsos, cement, Acrylic One and Multicast polyurethane resinsas well as for decorative designs, complex geometry and pieces with very fine details.

For technical product indicators please visit the "Specifications" table and for work examples the "Video" table.