Core Solution: Aiming at the non-spreading problem of 1000cst amino silicone oil on steel plates, the core is to reduce surface tension and optimize film-forming spreadability. Combined with the characteristics of the medium-high viscosity of 1000cst, three types of practical solutions are proposed: direct modification (formula adjustment), process optimization and substrate pretreatment, with specific parameters and operating methods attached.

I. Direct Formula Adjustment (Most Core, Adapted to 1000cst System)

Solution 1: Add Special Non-Ionic Spreading Additives (Highly Recommended, Strong Practicability)

• Selection Parameters: Choose polyether-modified silicone spreading agents (compatible with amino silicone oil) with surface tension ≤24mN/m, HLB value 8~12 and effective content ≥98%. Avoid ionic additives (which will damage the film formation of amino silicone oil).
  Recommended models: BYK-306, Dow Corning DC-51, Shin-Etsu KF-6011 (all industry universal, infinitely miscible with 1000cst amino silicone oil).
• Addition Amount: 0.2%~0.8% (based on the total mass of amino silicone oil), ≤1% (excess will cause sticky film formation and reduced slip property).
• Operation Method: Dilute the spreading agent with a small amount of xylene/white mineral oil (1:1), add it slowly while stirring the amino silicone oil (300~500rpm), and stir for 10~15min until a homogeneous phase is formed without delamination.

Solution 2: Blending with Low-Viscosity Silicone Oil (Auxiliary Viscosity Reduction + Improve Spreading, No Change to Main Components)

• Selection Parameters: Dimethyl silicone oil (50~100cst, CAS 9006-65-9) or low-amine value amino silicone oil (500cst, amine value 0.2~0.4mmol/g).
• Blending Ratio: 1000cst amino silicone oil : low-viscosity silicone oil = 9:1 ~ 8:2 (the viscosity of the blended system is about 800~900cst, the spreadability is increased by more than 30%; if the ratio is ＞1:1, the film-forming adhesion will decrease).

Solution 3: Dilution with Trace Polar Solvent (Emergency Solution, Suitable for Small-Batch Trial)

• Selection: Ethylene glycol monobutyl ether (EB, CAS 111-76-2), dipropylene glycol methyl ether (DPM, CAS 34590-94-8). DPM is preferred (low odor, better compatibility with amino silicone oil).
• Addition Amount: 1%~3% (excess will cause slow film-forming drying and pinholes). Stir until completely dissolved before use.

II. Steel Plate Substrate Pretreatment (Eliminate Surface Impurities, Improve Surface Energy, Basic Premise)

1. Degreasing Treatment: Spray/soak the steel plate with neutral degreaser (concentration 3%~5%, temperature 40~50℃) for 5~10min, rinse with clean water and dry (no water marks or oil film on the surface);
2. Activation Treatment (Optional, for cold-rolled/galvanized steel plates): Wipe the surface with dilute phosphoric acid (concentration 1%~2%) to remove the oxide layer, rinse with clean water and dry, so that the surface energy of the steel plate is increased to 35~40mN/m, which greatly improves the wettability of silicone oil;
3. Dust-Free Operation: Operate the pretreated steel plate in a clean room (cleanliness ≥100,000 class) to avoid secondary contamination.

III. Construction Process Optimization (Adapted to 1000cst Viscosity, Improve Spreading Uniformity)

1. Construction Method: Prioritize microgravure roll coating or air atomization spraying instead of brush coating/knife coating;
   • Roll coating: Select 100~120 mesh microgravure roll, roll speed 10~15m/min, pressure 0.1~0.2MPa to ensure uniform transfer of silicone oil to the steel plate surface;
   • Spraying: Spray gun nozzle diameter 0.8~1.0mm, spraying pressure 0.3~0.4MPa, gun distance 20~30cm, thin coating for 2~3 times (wet film thickness 5~8μm/time) to avoid material accumulation due to thick coating.
2. Construction Temperature: Control at 25~35℃, humidity ≤60%; low temperature (＜15℃) will lead to increased viscosity and decreased fluidity of silicone oil, while high temperature (＞40℃) will cause rapid solvent volatilization, and silicone oil forms a film before spreading.
3. Pre-Drying Treatment: After coating, pre-dry at 60~80℃ for 5~10min to allow full spreading of silicone oil, then raise the temperature to the curing temperature (120~150℃) for curing to avoid edge shrinkage caused by direct high-temperature curing.

IV. Key Notes (Avoid Solution Failure, Ensure Stability)

1. Conduct compatibility tests for all additives/solvents with 1000cst amino silicone oil (stir at room temperature and stand for 24h, no delamination or precipitation means compatibility);
2. The amine value of amino silicone oil must match: if the amine value is too high (＞0.8mmol/g), the molecular polarity is too strong and easy to agglomerate, resulting in decreased spreadability. It is recommended to control the amine value at 0.4~0.6mmol/g (conventional matching amine value for 1000cst);
3. Film thickness control: wet film thickness ≤20μm, dry film thickness 8~12μm. Thick film is prone to sagging and edge shrinkage, while thin film is easier to spread uniformly;
4. Curing process: curing temperature 120~150℃, time 15~20min. Insufficient curing will lead to sticky film formation and poor adhesion, which indirectly affects the film-forming effect after spreading.

V. Effect Verification Standards

After treatment, the amino silicone oil should achieve 100% spreading on the steel plate surface without edge shrinkage, pinholes or material accumulation. After film formation, the adhesion grade tested by cross-hatch cutter is ≥0, the surface is smooth and non-sticky to the touch, and no film peeling or yellowing occurs after being placed in high temperature and high humidity environment (40℃, 90%RH) for 48h.