Super Stable High Concentrated Silicone Oil RH-NB-973G

Super Stable High Concentrated Silicone Oil RH-NB-973G is a high-solids organofunctional silicone fluid supplied for in-plant dilution before use. The model designation RH-NB-973G identifies the concentrate grade in purchase specifications and process records; it is not a ready-to-use emulsion or a low-viscosity release fluid. Because no public lot certificate for this specific designation is available at the time of writing, numerical values in the specification table are class-representative ranges for high-concentrate organopolysiloxane fluids with non-volatile content above 98 wt%. Batch acceptance must be made against the producer’s certificate of analysis. The product class is relevant to textile wet finishing, rubber release, and industrial film-forming operations where high silicone active content is required with reduced transport water.

The non-volatile content method ISO 3251 does not distinguish between volatile cyclics and water. For high-concentrate silicone fluids, a headspace gas chromatographic method may be required if cyclosiloxane residues are regulated. The viscosity value is spindle-speed dependent; a single-point viscosity is insufficient for pump sizing. Flow-curve measurement with a rotational rheometer at 0.1–100 s⁻¹ is recommended before production-scale pumping.

What shear and dilution limits govern softflow and jet wet-end application?

In low-liquor-ratio softflow machines, the circulation pump and transport nozzle impose high shear on any injected liquor. Direct injection of the concentrate into a return line with differential pressure above 1.0–1.5 bar can produce local shear rates above 10,000 s⁻¹. For a non-Newtonian high-solids silicone fluid with low-shear apparent viscosity of 4000–7000 mPa·s, this shear may cause droplet coalescence, phase inversion, and deposition on crease edges. The concentrate is therefore pre-diluted to 10–20 wt% silicone solids before entering the machine. Demineralized water with total hardness below 200 mg/L CaCO₃ is used. The dilution vessel is stirred with a low-shear propeller at 300–500 rpm; high-shear dispersers are specifically avoided. The working dispersion is then metered into a bath held at pH 5.5–6.5 and temperature 30–40 °C. Exhaustion time is 20–30 min under constant circulation. The bath should not be acidified below 5.0, because acidic conditions can destabilize the weak cationic or non-ionic dispersion and may contribute to fabric tendering when residual acid is present. If the bath contains residual anionic dyes, levelling agents, or electrolyte above 500 mg/L, bench-scale compatibility testing in a 1 L jar is required before production. Published machine-specific data for RH-NB-973G is limited; the above limits reflect industrial practice for similar high-concentrate organofunctional silicone fluids.

In continuous padding of cellulosic and synthetic knitted fabrics, a working bath is prepared at 5–30 g/L of the concentrate. A horizontal two-roll pad mangle with pip pressure 2–4 bar and roll hardness 70–80 Shore A is typical for wet pickup of 70–85%. The pad trough is fitted with a slow stirrer; high-shear circulation through a recirculation pump is not used because it can entrain air and destabilize the dilute dispersion. After impregnation, the fabric enters a stenter frame and is dried at 120–130 °C followed by curing at 150–170 °C for 30–60 s. Process water with bicarbonate alkalinity above 150 mg/L CaCO₃ is adjusted to the acidic side of the working pH range to avoid water spotting. Hand is evaluated using an instrumented Kawabata KES system or a trained panel under AATCC EP5; no universal hand value is assigned because the result depends on substrate construction, temperature history, and dyestuff. Tensile property retention, when required, is tested according to ASTM D5034-09. Optical yellowing risk is screened with AATCC TM138 or ASTM D1925. The concentration of the high-solids fluid should be increased by no more than 5 g/L increments during process adjustment, because steep changes in active silicone can create uneven surface deposition and shade change.

Foam generation in the pad trough is controlled by low-shear mixing and by avoiding dilution water temperatures below 15 °C. When scum or oily deposit is observed on the pad rolls after 30 min of running, the bath is not reused; the source is usually incompatible anionic surfactant residue. No antifoam should be added without a compatibility test, because silicone antifoams may aggravate surface deposition.

Emulsification of RH-NB-973G for water-based use is further controlled by oil addition order. The oil phase is added slowly to the water/surfactant phase under low-shear agitation; reverse addition can produce water-in-oil phase inversion that increases apparent viscosity and reduces filtration performance. The emulsion is then checked by laser diffraction according to ISO 13320-1. A median particle size below 500 nm is desirable for pad-bath stability; values above 1 μm are associated with oil-spot defects on fabric edges. If the emulsion is filtered before dosing, a bag filter with nominal retention of 10 μm may be used, but the pressure drop should not exceed 0.2 bar to avoid shear-induced coalescence. RH-NB-973G-specific dispersion data is not published.

When RH-NB-973G replaces a 30 wt% active amino-silicone emulsion in existing textile recipes

The replacement must be calculated on active silicone mass rather than product volume. A conventional recipe may contain 2.0% on weight of fabric of a 30 wt% active emulsion, yielding 0.6 wt% active silicone. For RH-NB-973G at 98 wt% non-volatile silicone, the equivalent dose is approximately 0.6 wt% product, not 2.0 wt%. The larger volumetric addition of the emulsion is not required and would overdose the bath. The high-concentrate fluid reduces the mass and volume of transported chemical per kilogram of active silicone, but it imposes pre-dilution and low-shear handling that the emulsion may not require. A recipe transfer should include a bench pad trial and a fabric yellowing evaluation before bulk adoption. The comparison below is class-level; site-specific performance for RH-NB-973G must be verified on the intended softflow or pad line.

The differences in water content are material for warehouse operations. A 200 L drum of high-concentrate may contain more active silicone than a 200 L drum of 30 wt% emulsion by a factor of approximately 3–3.3, but the same drum cannot be used directly in high-shear equipment. Storage and handling instructions therefore differ.

For mould release and industrial film formation, RH-NB-973G is used as a solvent-borne or water-emulsified silicone film former. In a solvent-borne mould release for rubber or thermoset processing, the high-solids fluid is added at 0.5–2.0 wt% of the total formulation in isoparaffinic solvent. Film durability is related to the high molecular weight of the silicone. Published thermogravimetric analysis for high-viscosity polydimethylsiloxane fluids under nitrogen at 10 °C/min reports 5% mass loss near 250 °C; publication for RH-NB-973G itself is limited. In an aerobic mould environment, continuous service above 200 °C can produce oxidative crosslinking and silica residue. For water-based release emulsions, the concentrate is pre-emulsified with a non-ionic ethoxylated alcohol at 10–20 wt% silicone solids in a low-shear vessel. Emulsions with median particle size above 1 μm may separate on mould surfaces and should be rejected. The water-based emulsion should be consumed within 24 h unless a preservative is added and validated.

On an injection moulding machine with clamp force 80–120 t and mould temperature 150–200 °C, release performance is evaluated by ejection force and mould fouling over 500 cycles. The high concentration permits the formulator to adjust silicone film thickness without adding large amounts of solvent. Compared with low-viscosity polydimethylsiloxane release oils in the 50–1000 mPa·s range, the high-concentrate class generally provides a more substantial lubricating film but lower wetting on polished metal. Low-viscosity oils may be preferred for tight die-casting moulds with low ejection-force margins, while the high-solids fluid is selected where a durable elastomeric release layer is needed. A high-concentrate film may require a wax or hydrocarbon co-component to improve spreading. Published comparative data for RH-NB-973G is limited; pilot testing is required before production.

Storage of the high-concentrate is specified for sealed HDPE or lined mild steel drums at 5–40 °C. The concentrate should not be stored in direct sunlight or near steam lines. Moisture ingress through open bungs may hydrolyze the organofunctional groups and cause a slow increase in low-shear viscosity. If the product contains amino-functional siloxane moieties, storage at pH below 5.0 after accidental water ingress may protonate amine sites and alter emulsification behavior. The product must not be blended with strong oxidizers, alkali metal hydroxides, or acid catalysts prior to use. Amine-reactive crosslinkers, such as epoxide or isocyanate systems, can cause premature gelation in the drum. Because the water content is below 2 wt%, the concentrate has a lower initial risk of microbial growth than ready-to-use emulsions. However, any dilution with process water introduces nutrients and contamination. If diluted product is held for more than 24 h, an in-plant preservative validated for the specific organism load is required. No microbiological test for RH-NB-973G is published; industrial sites use dip slides and plate counts under ISO 21149 or equivalent practices for dilute silicone emulsions. Shelf life for this class is commonly assigned as 12 months from production when unopened and stored under the stated conditions. No published shelf-life data specific to RH-NB-973G is available; the supplier’s certificate remains the controlling document.

Regulatory documentation for the concentrate should be maintained under REACH Article 31 for EU shipments and OSHA HCS for the United States. If any substance in the product triggers SVHC reporting at 0.1 wt% or higher, the supplier must communicate it under REACH Article 33. No RoHS-restricted substance declaration should be assumed for electronic applications without a written supplier attestation. This paragraph is a compliance requirement and does not imply that RH-NB-973G contains such substances.

For incoming inspection, the release criteria are non-volatile content according to ISO 3251 and dynamic viscosity according to ASTM D2196. A drum is accepted if the non-volatile content is not less than 98 wt% and the viscosity at 25 °C is within ±10% of the supplier certificate value. The incoming inspection also includes a dilution test: a 10 wt% dispersion in deionized water is prepared at 25 °C with propeller stirring at 400 rpm, and separation is observed after 24 h. Any phase separation, gel particles, or floating oil film triggers a supplier deviation and a pilot pad trial before production release. This procedure aligns with ISO 9001 incoming inspection requirements but does not replace a complete certificate of analysis or a regression test on the intended fabric.