POLYUREA COATING – Ultra-durable Coating

1. Application

– This technical instruction is applied to concrete and steel foundation surfaces of civil, industrial, irrigation, hydropower, technical infrastructure, underground tanks, swimming pools, pipelines, tunnels, etc.

– Apply hot-sprayed Polyurea-based products manufactured by Newtec Group Joint Stock Company.

– The product is used for the purpose of waterproofing, chemical corrosion resistance, abrasion resistance, non-stick, crack resistance, penetration resistance, anti-slip, impact resistance, etc.

2. Requirements
   • Surface preparation: Polyurea products shall be applied only after the surface (concrete or steel) has been completely cleaned, and the water content should be less than 8% for effective coating application. The concrete or mortar foundation must be at least 28 days old. The steel base must be roughened to SA 2.5.
   • Environmental Conditions:

– Do not apply the product on rainy days.

– Do not apply the product in bad weather such as strong winds.

– Suitable surface and environmental temperature is from 5℃ to 45℃. And air humidity is not more than 85%.

– When applied in basements or places with poor ventilation conditions, careful protective equipment and ventilation equipment must be equipped.

• Construction site: The construction site must have a minimum space to be able to clean the concrete surface and spray Polyurea. Polyurea can be sprayed on flat surfaces, vertical surfaces, inclined surfaces, curved surfaces or ceilings… without sagging.
• Material:

– Primer: Epoxy-based coat (0.25 kg/m2, 1 to 2 coats) is often used for underground tank, pipe or floor. 1-component polyurethane-based coat (0.2 kg/m2, 1 to 2 coats) is often used for waterproofing roofs of buildings or places that do not require high adhesion to the substrate.

– Waterproofing and anti-corrosion coating: Polyurea-based products (from 1.5 kg/m2 or more) manufactured by Newtec Group Joint Stock Company such as: NEWTECOAT PUA-200; NEWTECOAT PUA-200S; NEWTECOAT PUA – 400; or other specialized types.

– Top coat (0.15 kg/m2): If necessary to increase the ability to prevent UV rays and keep the color durable (anti-fading).

– Material inspection process: Materials must be checked for intact seals, expiry date, etc. by the supervisor and confirmed by the delivery staff at the delivery location.

2.5 Polyurea spraying equipment:

It is recommended to use Graco Airles Paint Sprayers made in the USA: GRACO E10HP; GRACO EXP-2. The higher the spraying pressure, the better the quality of the Polyurea film. The pressure when spraying should be maintained at a minimum of 2000 Psi to 2500 Psi. Graco equipment operators and spray gun workers must be thoroughly trained by NEWTEC Engineers before use.

3. Construction Process

3.1 Check and repair surface :

– Flatten the surface: Use machines or manual methods to remove the roughness of the surface, and patch the holes and defects with high-quality leveling mortar or repair mortar. For old concrete floors, damaged areas should be repaired and reinforced with high-quality materials to create a flat surface.

– Clean the new surface concrete: It is recommended to use grinder to grind off the top layer of cement mortar.  And blow high pressure air to clean the surface (can clean with pressure water in case the surface is too dirty). The concrete surface must be solid, not seeping back, not broken or floating…

–  Clean old paint: All previous paints must be cleaned to ensure the adhesion of Polyurea to the substrate.

– Thorough treatment of holes is very important before spraying Polyurea to avoid air explosion, warts, etc.

–  Before applying Polyurea products, the surface must comply with the regulations in section 2.1.

3.2 Apply primer coat

– Worker can apply primer coat by brush, roller, or spray gun.

– The primer coat needs to be cured to a certain dry standard (usually 2-3 hours for polyurethane-based primer and 4-5 hours for epoxy-based primer) after applying. Do not wait too long (over 10-12 hours) without applying Polyurea paint. The adhesion of the Polyurea coat may be reduced if the primer coat is too dry.

• Apply Polyurea coat

– It is necessary to ensure that all surface and environmental conditions are well prepared.

– Check the quality of the sprayer: The Graco machine must be checked and ensured that the machine can heat up well. The pressure of the machine is large enough to reach 2000-2500 Psi. The pistons operate smoothly. The two pressure gauges of Part A and Part B must display the same index, and have equal pressure to spray at a 1:1 ratio by volume…

– Check the quality of the air compressor: The air compressor has the function of providing compressed air to open the “trigger”, providing air to the raw material pump and supporting the dispersion of part of the paint at the gun tip. The operator needs to check the air filter to ensure that the quality of the incoming air is dry and free of water.

– It is necessary to stir part B of Polyurea product within 30~60 minutes before using. This step will help ensure that the color is consistent and there are no inconsistencies.

– Part A and Part B of Polyurea must be heated to 60 ~ 70⁰C before spraying (not exceeding 70⁰C).

– The Polyurea layer is sprayed evenly and reaches the designed thickness by skilled and experienced technical workers trained by Newtec Group Joint Stock Company.

–  When spraying Polyurea onto a concrete surface, if the paint surface appears to have blisters or air bubbles after 10-30 seconds of spraying, the worker must stop spraying immediately. The worker must check and re-evaluate the surface quality. This problem occurs due to several reasons such as: the surface has not been properly primed; the surface still has holes; the floor is still damp; the air humidity is higher than 85%; the gun tip is dripping paint; Part A and Part B are not evenly distributed…

4. Inspection and acceptance

• The standard or thickness: Workers must check the standard according to the design. The thickness can be checked by ultrasonic machine or checked from any small piece cut out to measure with calipers.
• Adhesion test: Workers sprays Polyurea onto concrete samples (Same concrete Grade) that prepared on site to test adhesion according to ASTM D4541 or equivalent standards.
• Other tests: Elongation (ASTM D412), tensile strength (ASTM D412). In addition, abrasion resistance (ASTM D4060); water resistance (BS EN 14891:2017); tear resistance (ASTM D624); crack bridging ability (BS EN 14891:2017); impact resistance (ASTM D4508), etc. These tests are conducted by spraying samples on site. These samples are tested at LAS laboratories licensed by the Ministry of Construction/Department of Construction.
• Check and fix defects:

– Construction according to instructions will not have any defects. However, due to some reasons such as: humid weather, high humidity of the ground, poor quality of spraying machine, poor spraying worker skills, low quality of the surface, water-permeable or broken concrete, floating… the paint layer may have defects such as: pimples, blisters, air pressure like a balloon… Therefore, the worker needs to check immediately by eye or dry paint film defect inspection equipment to ensure quality and can timely repair.

– Fix the defect:

+ Use a sharp and thin blade to cut around the blister area. And use abrasive disc machine to grind the polyurea film around the cut area in a shape with width of 5-10 cm. Grind the concrete surface, blow off the dust and apply a primer coat to the concrete surface (do not apply primer over the polyurea coat). And then spray a new polyurea coat according to the above procedure. In cases, high adhesion is required, workers can use a specialized material to gently wipe the polyurea surface around the cut area to “awaken” the polymer chains in the previously sprayed coat.

+ The old polyurea layer is not too inert due to long-term continuous contact with water and chemicals (over 12 months). If the old polyurea layer is inert, the adhesion between the new layer and the old layer is not good.

5. Occupational Safety

• When applying primer and spraying Polyurea, make sure to keep away from fire sources.
• For indoor construction, air must circulate well to ensure workers’ health.
• The process of installing the power supply line for the Polyurea sprayer must be carried out under the supervision of a qualified technician. The current and voltage must be large enough to supply the sprayer.
• It is necessary to strictly comply with general regulations on environmental protection, fire prevention and occupational safety of the host country.

6. Guarantee

– Newtec Group Joint Stock Company commits to guarantee the quality of materials when customers comply with technical instruction and product TDS. Any damage caused by failure to comply with technical instructions will not be covered by our warranty.

– Contact NEWTEC GROUP Customer Service to get answer satisfactorily and quickly.