Sikaflex®-423 PowerCure

• CE marking and declaration of performance based on EN 15651-1:2012 Sealants for non-structural use in joints in buildings and pedestrian walkways — Part 1: Sealants for facade elements.

• CE marking and declaration of performance based on EN 15651-4:2012 Sealants for non-structural use in joints in buildings and pedestrian walkways — Part 4: Sealants for pedestrian walkways.

• Testing of the booster accelerated joint sealant EN 15651-1, SKZ, No. 220740/21-VII.

• Testing of the booster accelerated joint sealant EN 15651-4, SKZ, No. 220740/21-VIII.

• Testing of the booster accelerated sealant ISO 11600, SKZ, No. 220740/21-IX.

EN 15651-4: PW EXT-INT CC 25 HM

Accelerated Sika® Purform® Polyurethane Technology

15 months from date of production

The product must be stored in original, unopened and undamaged sealed packaging in dry conditions at temperatures between +5 °C and +25 °C. Always refer to packaging.

• Non-staining on many natural stones according to ASTM 1248-04 and ISO 16938-1.

• To confirm suitability, tests must be carried out according to ISO 16938-1 or ASTM 1248-04 before using on natural stones and full project application.

FINAL SHORE A HARDNESS

~40 (after 28 days)

80 % DEVELOPMENT OF SHORE A HARDNESS

DEVELOPMENT OF SHORE A HARDNESS

Testing conditions +23 °C / 50 % rH.

Resistant to many chemicals. Refer to EN 15651-4 SKZ test report for water and salt water. Contact Sika Technical Services for additional information.

The joint dimensions must be designed to suit the movement capability of the sealant. The joint width must be a minimum of 10 mm and a maximum of 40 mm.

All joints must be correctly designed and dimensioned in accordance with the relevant standards and codes of practice before their construction. The basis for calculation of the necessary joint widths are:

• The type of structure

• Dimensions

• Technical values of adjacent building materials

• Joint sealing material

• The specific exposure of the building and the joints

A width to depth ratio of 1:0.8 for floor joints must be maintained (for exceptions, see table below).

For larger joints, contact Sika ® Technical Services for additional information.

Example for typical joint widths for joints between concrete elements for interior applications considering 25 % movement capability according to EN 15651-4:

Example for typical joint widths for joints between concrete elements for exterior applications considering 25 % movement capability according to EN 15651-4:

For details of joint design and calculations refer to the following document, Sika® Design guidlines: Dimensioning of construction joints.

For applications at temperatures below +5 °C, please contact Sika Techincal Services.

The substrate temperature must be +3 °C above dew point temperature and free from frost and ice.

Use closed cell, polyethylene foam backing rod

~15 minutes (+23 °C / 50 % r.h.)

IMPORTANT

Bituminous, natural rubber or EPDM rubber substrates

Do not use the product on any building materials which might leach oils, plasticisers or solvents that could degrade the sealant.

Primers are adhesion promoters and not an alternative to improve poor preparation or cleaning of the joint surface.

Note: Primers also improve the long term adhesion performance of the sealed joint.

Substrate testing

Note: Adhesion tests on project specific substrates must be performed and procedures agreed with all parties before full project application. For more detailed advice and instructions contact Sika Technical Services.

The substrate must be sound, clean, dry and free of all contaminants such as dirt, oil, grease, cement laitance, old sealants and poorly bonded coatings which could affect adhesion of the sealant.

The substrate should be of sufficient strength to cope with the stresses induced by the sealant during movement. Removal techniques such as wire brushing, grinding, grit blasting or other suitable mechanical tools must be used. Repair all damaged joint edges with suitable Sika repair products. All dust, loose and friable material must be completely removed from all surfaces before application of any activators, primers or sealant.

Where joints in the substrate are saw cut: After sawing, all slurry material must be flushed away and joint surfaces allowed to dry.

For optimum adhesion, joint durability and critical, high performance applications such as joints on multi-storey buildings, highly stressed joints, extreme weather exposure the following priming and pre-treatment procedures must be followed:

NON-POROUS SUBSTRATES

Aluminium, anodised aluminium, stainless steel, galvanised steel, powder coated metals, or glazed tiles:

1. Lightly roughen the surface with a fine abrasive pad.
2. Clean and pre-treat using Sika® Aktivator-205 applied with a clean cloth.

Other metals, such as copper, brass and titanium-zinc:

1. Lightly roughen the surface with a fine abrasive pad.
2. Clean and pre-treat using Sika® Aktivator-205 with a clean cloth.
3. Wait until the flash off time has been achieved.
4. Apply Sika® Primer-3 N by brush.

PVC substrates:

1. Clean and pre-treat using Sika® Primer-215 applied with a brush.

POROUS SUBSTRATES

Concrete that is 2–3 days old, or matt wet (surface dry):

1. Prime surface using Sika® Primer-115 applied by brush.

Concrete, aerated concrete and cement based renders, mortars and bricks:

1. Prime surface using Sika® Primer-3 N or Sika® Primer-115 applied by brush.

Reconstituted, cast or natural stone:

1. Preliminary trials must be carried out to check if the stone experiences plasticiser migration. For a suitable primer to prevent plasticiser migration, contact Sika ® Technical Services for further information.

ASPHALT (ACCORDING TO EN 13108-1 AND EN 13108-6)

Fresh cut or existing cut asphalt must have a clean bonding surface with minimum 50 % exposed aggregate:

1. Prime surface using Sika® Primer-3 N or Sika® Primer-115 applied by brush.

For more details of the primer or pre-treatment products refer to the individual Product Data Sheet. Contact Sika Technical Services for additional information.

1-part accelerated by PowerCure®.

IMPORTANT

Swimming pools

Do not use to seal joints in and around swimming pools.

IMPORTANT

Exposure to alcohol during curing

Do not expose the product to alcohol-containing products during the curing period as this may interfere with the curing reaction.

1. Apply masking tape where neat or exact joint lines are required. Remove the tape within the skinning time of the product after finishing.
2. After the required substrate preparation, insert a backing rod to the required depth.
3. Prime the joint surfaces as recommended in substrate preparation. Avoid excessive application of primer to avoid causing puddles at the base of the joint.
4. Set up the PowerCure Dispenser according to the PowerCure User Manual. Cut the nozzle to the required bead size.
5. IMPORTANT: Replace the mixer if the application is discontinued for more than 10 minutes (at +23 °C). Extrude the product into the joint ensuring that it comes into full contact with the sides of the joint and avoiding any air entrapment. Temperature will affect product reactivity and application properties.
6. IMPORTANT: Do not use tooling products containing solvents. As soon as possible after application, tool the sealant firmly against the joint sides to ensure adequate adhesion and a smooth finish. Use a compatible tooling agent such as Sika® Tooling Agent N to smooth the joint surface.

Over-painting the sealant

Note: The product can be over-painted with most conventional paint coating systems. However, paints must first be tested to ensure compatibility by carrying out preliminary trials (according to the ISO technical paper: Paintability and Paint Compatibility of Sealants). Optimum results are obtained when the sealant is allowed to fully cure first. Note: non-flexible paint systems may impair the elasticity of the sealant and lead to cracking of the paint coating. Depending on type of paint used, plasticiser migration may occur causing the paint to become surface ‘tacky’.

Colour variations

Note: Colour variations may occur due to the exposure in service to chemicals, high temperatures or UV-radiation (especially with white colour shade). This effect is aesthetic and does not adversely influence the technical performance or durability of the product.

Clean all tools and application equipment immediately after use with Sika® Remover-208. Once cured, hardened material can only be removed mechanically. For cleaning skin use Sika® Cleaning Wipes-100.