In the application of protective coatings on substrates such as metals, glass, ceramics, and composite materials, traditional curing systems often have to make a trade-off between "high hardness" and "high transparency", "normal temperature application" and "excellent adhesion". The organic polysilazane 9150K utilizes the dual curing mechanism of Si-NH-Si bonds reacting with the hydroxyl groups on the substrate surface and undergoing hydrolysis and oxidation at room temperature. It can achieve a surface dry time of 5-10 minutes at room temperature and complete curing within 48 hours. The maximum hardness can reach 7H, and the visible light transmittance is >95%. The adhesion to metals is 0 grade according to the scratch test, making it a candidate base material for high transparency and high hardness protective coatings.


Why do organic polysilazane coatings often fail to cure adequately, have insufficient adhesion, or achieve the expected hardness during construction or use?


The construction environment has too low humidity or too low temperature, preventing the effective hydrolysis curing of Si-NH-Si bonds.


The choice of diluent solvents is inappropriate - the product is miscible with most non-polar solvents (alkanes, ethers, ketones, esters), but alcohol ether solvents (such as diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol butyl ether) should not be used.


The container was not sealed in time after use, allowing moisture from the air to enter and causing the resin to prematurely hydrolyze and deteriorate.


Insufficient curing time - complete curing at room temperature requires more than 48 hours, and insufficient curing time will affect the final hardness.


The surface cleanliness of the substrate is insufficient, affecting the reaction and bonding of Si-NH-Si bonds with surface-OH.


When curing at high temperatures, the surface drying was not completed before the curing process, resulting in blistering or uneven curing of the coating.


First, determine at which stage the coating problem occurs.


Failure stage Possible causes Priority inspection direction
Slow or incomplete curing Too low humidity, too low temperature, resin has hydrolyzed and deteriorated Environmental humidity/temperature, container sealing, solvent selection
Insufficient curing hardness (<5H) Insufficient curing time or improper curing conditions Is the room temperature curing time > 48 hours, high-temperature curing conditions
Poor adhesion between coating and substrate Unprocessed substrate surface or residual solvents Surface cleanliness, drying conditions, type of diluent solvent
Transmittance of coating lower than 95% Improper curing conditions leading to phase separation or contamination Construction environment cleanliness, curing procedure
Air bubbles or pinholes in coating Not completing surface drying before high-temperature curing Is the surface drying time (5-10 minutes) sufficient
Shortened storage period or resin deterioration Resin enters the container Container sealing, inert gas replacement operation
Comparison reference for 9150K and 9283


Comparison item 9150K 9283
Fluorine-containing modification No (non-fluorine system) Yes (fluorine-modified hydrophobic)
Curing hardness 24h: 5H / 48h: 7H 12h: 4H / 24h: 6H
Hydrophobic angle No labeled hydrophobic property 110-120°
Room temperature surface dry time 5-10 minutes 10-15 minutes
Transmittance >95% >95%
Metal adhesion 0 grade 0 grade
Which conditions need to be confirmed before selection and construction?


Condition category Required information
Substrate type Metal, alloy, glass, paint film, plastic, etc.
Substrate treatment Surface cleanliness, drying degree
Construction method涂抹， immersion coating， spraying， brushing
Curing conditions Room temperature curing (≥48h) or temperature increase curing (surface drying followed by 120-150°C × 2-5h or 280-320°C × 2h)
Performance goals Hardness requirements (5H-7H)， transmittance (>95%)， adhesion (0 grade)
Diluent solvents Alkanes， ethers， ketones， esters (strictly prohibit alcohol ether solvents)
Storage conditions Dry and cool， after use inert gas replacement， sealing
Which key indicators should be verified?


Verification item Main function Not replaceable content
Hardness after curing (5H - 7H) - To verify the curing degree and scratch resistance - The hardness after room temperature curing is different from that after high-temperature curing
Transmittance (>95%) - To verify the optical transparency - It needs to be verified after curing
Adhesion (scratch test 0 grade) - To verify the bonding force with the substrate - It needs to be verified on different substrates
Drying time after surface - To determine the construction interval - It cannot represent complete curing
Complete curing time (<48h) - To verify the usable period - Hardness compliance does not represent long-term performance
Recommended construction scheme


Work under dry, cool, and ventilated conditions, and take necessary protective measures (gloves, masks, etc.).


Ensure that the substrate surface is thoroughly cleaned and dried to ensure the existence of active sites for the reaction with Si-NH-Si bonds.


Choose the appropriate construction method (application, immersion, spraying, brushing) based on the substrate type.


Select an appropriate solvent (alkanes, ethers, ketones, esters) to adjust the construction viscosity.


After construction, allow 5-10 minutes of normal temperature surface drying.


You can choose to accelerate the curing process by heating up, but it must be completed after surface drying.


Allow the product to cure at room temperature for at least 48 hours, or perform high-temperature curing (120-150℃ × 2-5h or 280-320℃ × 2h).


It can be miscible with various resins (such as epoxy silicone resin, organic silicone resin), and mixed use can shorten the curing time and increase the hardness.


Common misunderstandings


It can reach the highest hardness after 24 hours of room temperature curing: The hardness of this product after 24 hours of room temperature curing is 5H, and complete curing requires more than 48 hours, with a hardness of up to 7H.


It can be put into use after surface drying: Surface drying (5-10 minutes) only indicates the initial formation of the surface film, complete curing requires more than 48 hours at room temperature.


All solvents can be used for dilution: This product is not soluble in alcohol-ether solvents (such as diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol butyl ether).


High-temperature curing does not require completing surface drying first: High-temperature curing should be performed after surface drying at room temperature first, and direct high-temperature curing may cause blistering.


Storage period is the same as 9283: The unopened 9150K has a shelf life of more than one year.


FAQ


What is the curing mechanism of the 9150K?
It achieves curing through the hydrolysis and oxidation reactions of Si-NH-Si bonds, and simultaneously forms chemical bonds with the surface of the substrate through the reaction of Si-NH-Si bonds with -OH groups on the substrate surface, resulting in excellent adhesion (0 grade according to the scratch test).


What is the hardness after curing?
The hardness can reach 5H after 24 hours of room temperature curing, and 7H (pencil hardness) after 48 hours of room temperature curing.


What is the transmittance?
The visible light transmittance is >95%, suitable for optical or display fields that require high transparency.


What curing methods are available?
Two curing methods: 1) Room temperature curing: surface drying 5-10 minutes, complete curing <48 hours; 2) Heating curing: surface drying followed by 120-150℃ × 2-5 hours or 280-320℃ × 2 hours.


Which substrates can this product be used for?
It is suitable for various substrates such as metals, alloys, glass, and paint films, with excellent adhesion. However, it is recommended to conduct adhesion verification separately on different substrates.


How long is the storage period?
Unopened, the shelf life is more than one year. After use, the container should be sealed in time. If used in a humid environment, the air in the container should be replaced with inert gas.