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This coating product uses perhydropolysilazane IOTA PHPS as the main component and is stored diluted in solvent. It has 20% solids and n-butyl ether as the solvent. Curing mainly proceeds through hydrolysis of Si-N bonds: room-temperature curing requires more than 7 days; moisture curing can be completed in 2 hours at 90% humidity and 150°C. Selection should not rely only on “9H,” “800°C,” or “strong salt-water resistance.” First confirm the substrate and pretreatment, dilution and formulation, target film thickness, curing route, and project acceptance criteria.
This article does not equate pencil hardness, heat resistance, or salt-water performance with a specific salt-spray duration or outdoor service life. The product data also note that resistance to 10% hydrochloric acid is relatively weak, about one month; strong acid or long-term acidic environments require separate evaluation. IOTA can provide PHPS raw materials and corresponding product data; the company does not provide complete formulations or formulation development services.
PHPS coating materials are used in applications such as building anti-graffiti, precious metal anti-corrosion, rail transit, semiconductor insulating layers, electronic circuits, and moisture/gas barrier and water resistance for plastic packaging. Different applications focus on different properties: anti-graffiti on surface and stain resistance, anti-corrosion on rust, alkali, and salt-water resistance, electronics and semiconductors on insulation and film integrity, and packaging on barrier and water resistance. Selection should start with the target defect and application, not just “super-hard and stain-resistant.”
| What to confirm | What to specify in an inquiry or sample request |
|---|---|
| Substrate and pretreatment | Steel, precious metal, plastic, electronic substrate, etc.; degreasing, derusting, cleaning, and other treatments |
| Dilution and formulation | PHPS main component, n-butyl ether solvent, 20% solids, target dilution ratio; whether other additives are used |
| Coating build | Single layer or composite system; target dry film thickness; the data give coating thickness >100 nm |
| Curing route | Room temperature for more than 7 days; or moisture curing at 90% humidity, 150°C, 2 h; whether ammonia curing or high-temperature curing is used |
| Acceptance criteria | Hardness, elastic modulus, pencil hardness, transparency, adhesion, rust resistance, alkali resistance, salt-water resistance, acid-resistance boundary, heat resistance, etc. |
| Application | Anti-graffiti, anti-corrosion, rail transit, semiconductor insulating layer, electronic circuits, barrier and water resistance, etc. |
If the customer already has a test specification, obtain the original document first. When criteria are missing, confirm them with the project owner and test laboratory before making samples, so that both sides do not discover different interpretations of “pass” after testing.
PHPS curing mainly proceeds through hydrolysis of Si-N bonds. The data give two basic routes: room-temperature curing for more than 7 days; moisture curing at 90% humidity and 150°C for 2 hours. Different curing routes correspond to different property data: hardness is 3 GPa (ammonia curing) and 8–10 GPa (high-temperature curing); elastic modulus is 60 GPa (ammonia curing) and 100–130 GPa (high-temperature curing). Pencil hardness is listed as 9H (Zhonghua) and 6H (Mitsubishi); visible-light transparency is >90%; cross-cut adhesion is grade 0.
Therefore, the curing route must be stated when comparing candidate solutions. A tack-free or briefly pre-cured film does not necessarily mean the specified curing condition has been reached; hardness, modulus, and adhesion from different curing routes cannot be directly mixed.
The data give a coating thickness of >100 nm and a composition mainly of SiOx. Cross-cut adhesion grade 0 is a result obtained under the corresponding substrate, pretreatment, and film thickness. If actual workpieces have edges, welds, rough surfaces, or contamination residues, first confirm whether the pretreatment is suitable, and then evaluate the whole coating system. Transparency and appearance should also be confirmed separately on the target film thickness and substrate.
The product data state strong rust resistance, alkali resistance, and salt-water resistance; resistance to 10% hydrochloric acid is relatively weak, about one month; heat resistance in air is 800°C. Procurement or sample-request documents should write these as criteria under corresponding conditions, not broadly as “resistant to all acids and alkalis” or “long-term 800°C.” For strong acids, long-term high temperature, salt spray, or outdoor environments, separate tests and evaluations should be arranged. Semiconductor insulating layers and electronic circuits also require confirmation of electrical properties, film integrity, and process compatibility.
Obtain the customer’s service conditions and acceptance criteria; confirm whether hardness, adhesion, rust resistance, alkali resistance, salt-water resistance, acid-resistance boundary, and heat resistance are targets or existing results.
Specify substrate, surface treatment, PHPS dilution ratio, n-butyl ether system, target film thickness, and curing route.
Check the current IOTA PHPS data, then have the user make representative samples and keep records of formulation, dilution, curing temperature, humidity, and time.
Arrange tests as agreed; keep sample identity, test conditions, observation photos, and evaluation results in the report. Before expanding use, confirm whether the samples represent actual workpieces.
IOTA/Anhui Iota Silicone Oil Co., Ltd. positions itself as a solution provider across the organosilicon industry chain and can provide PHPS raw materials and corresponding product data. When communicating, provide the substrate, existing coating practice, target defects, and application equipment together to facilitate candidate screening; the company does not provide complete formulations or formulation development services.
First define the substrate, coating system, film thickness, curing route, and salt-spray criteria, and then obtain the corresponding test evidence. Strong salt-water resistance is not the same as having passed a specific salt-spray duration.
The data give room-temperature curing for more than 7 days. Whether it meets project requirements also depends on film thickness, humidity, and final acceptance criteria. The moisture-curing route is 90% humidity, 150°C, 2 h.
The data list 9H (Zhonghua) and 6H (Mitsubishi). Different pencil brands mean the results cannot be simply interchanged. Hardness is also affected by curing route and film thickness.
The data list heat resistance in air of 800°C. This number should be understood together with the specific formulation, substrate, time, and evaluation conditions; it cannot be directly converted into long-term continuous service temperature or outdoor service life.
The data clearly state that resistance to 10% hydrochloric acid is relatively weak, about one month. Strong acid or long-term acidic environments should be evaluated separately and not directly assumed.
It can be evaluated as a candidate approach, but first confirm the primer identity, interlayer adhesion, curing schedule, and compatibility of the whole coating system.
