New Type Super Fluffy and Soft Silicone Oil RH-NB-8368-6

New Type Super Fluffy and Soft Silicone Oil RH-NB-8368-6 is an amino-functional polysiloxane emulsion developed for textile finishing. The product is supplied with a nonionic emulsifier system and a pendant aminoalkyl modification on the polysiloxane backbone; this substitution pattern restricts thermally induced yellowing compared with terminal aminoalkyl silicone oils. According to the manufacturer’s specification, the neat product has an active silicone content of 60 ± 2 % by mass, a pH of 5.5–7.0 at 25 °C in a 10 g/L aqueous dilution, and a Brookfield viscosity of 200–800 mPa·s at 25 °C using ISO 2555. The product is dispersible in cold water under low-shear agitation. Table 1 lists the primary specification parameters. Storage should be maintained between 5 °C and 35 °C in closed containers; freeze-thaw cycling below 0 °C causes coalescence that cannot be reversed by re-mixing. The product is intended for continuous padding, exhaust soft treatment, and low-wet-pickup finishing. It is not recommended for spray application without additional dilution because the nonionic emulsion may deposit as a sticky film on atomiser nozzles when the bath concentration exceeds 50 g/L. The active amino-functional silicone content is verified after dilution by extraction with petroleum ether and gravimetric analysis according to ISO 2871-2; typical recovery in quality control is 98–102 % of the supplied solids.

What Processing Limits Govern Pad-Dry-Cure Application?

On a horizontal two-bowl pad mangle with a pneumatic nip pressure of 3–5 bar, the recommended working dilution is 10–30 g/L for woven cotton and polyester/cotton fabrics. The bath is adjusted with 60 % acetic acid to pH 5.0–5.5; below pH 4.0 the emulsion undergoes progressive droplet coagulation and may deposit as a tacky film on pad rolls. At wet pickup of 65–80 %, the applied silicone solids are 0.6–2.4 % on mass of fabric at the specified dilution. Drying is conducted in a stenter with first-zone air temperature of 80–100 °C and final cure at 150–170 °C for 60–120 s. The cure window is narrow: below 140 °C the alkoxy condensation reaction is incomplete and the film loses softness after five household laundering cycles under ISO 6330; above 170 °C the oxidised amino groups produce yellowness index increases greater than 2 units under ASTM E313. A production stenter running at 30 m/min with an 8-chamber range and total dwell of 90 s is sufficient when the final chamber is calibrated by fabric probe rather than air temperature.

During intermediate drying, migration of the silicone to fibre-fibre intersections becomes significant when fabric moisture content remains above 35 %. This creates back staining on perforated drum dryers and reduces hand uniformity. Reducing first-zone temperature to 80 °C or increasing bath solids limits migration but may require longer dwell. Bath stability at 25 °C is 6–8 h; after 8 h the mean droplet diameter increases from 40–80 nm to 120–180 nm, and visible pad roll deposition occurs. For foam finishing, a blow ratio of 4:1 and wet pickup of 20–25 % reduce drying load, but the antifoam component in the emulsion may suppress foam stability; a pilot trial is required before production.

In comparative pad applications on bleached cotton poplin, RH-NB-8368-6 differs from first-generation amino silicone emulsions and dimethylsilicone emulsions in measured handle, hydrophilicity, and whiteness retention. The relative hand value according to AATCC TM202 at a dose of 20 g/L is 8.2 for RH-NB-8368-6, 7.8 for a conventional amino silicone oil, and 5.5 for a dimethylsilicone control. Water droplet absorption time according to AATCC TM79 remains 6–10 s for RH-NB-8368-6, whereas the conventional amino silicone control exceeds 30 s and the dimethylsilicone control absorbs in 3–5 s. The whiteness change after curing at 165 °C for 90 s is less than 2 units for RH-NB-8368-6, compared with 5–8 units for the conventional amino silicone control. The data in Table 2 were obtained on a laboratory padder with a nip expression of 75 % and a stenter cure of 165 °C.

During thermal curing, the pendant amino-functional polysiloxane forms a crosslinked film on the cotton fibre surface. At a bath concentration of 20 g/L, transmission electron microscopy shows a film thickness of 50–150 nm; the film is discontinuous below 15 g/L and becomes continuous at higher loadings. The low amine content reduces the formation of carbonyl chromophores that cause yellowing above 160 °C. Yellowness index under ASTM E313 follows apparent first-order kinetics with a rate constant of approximately 0.012 min⁻¹ at 170 °C for RH-NB-8368-6, compared with 0.045 min⁻¹ for a conventional terminal-amino silicone fluid. Published data for this specific product on regenerated cellulose cured above 180 °C is limited. The measured softness improvement is associated with a reduction in fibre-to-fibre friction coefficient from approximately 0.35 to 0.18 on the Kawabata KES-SE surface tester; fibre swelling is not the primary mechanism.

In low-wet-pickup foam finishing, a foam generator with a blow ratio of 4:1 and wet pickup of 20–25 % is used. The product lowers drying energy, but its antifoam component can reduce foam half-life; a pilot trial is required. At wet pickup below 15 %, uneven spreading of the silicone film on hydrophobic polyester sections appears as oil spots under ultraviolet light. The product should be pre-diluted to 50–80 g/L before injection into the foam head. In crease-resist finishing with dimethyloldihydroxyethyleneurea, RH-NB-8368-6 is added to the resin bath at 20–40 g/L. The nonionic emulsion remains stable in the presence of magnesium chloride catalyst at 10–15 g/L; however, the bath pH must be held above 4.5 to avoid hydrolysis of the siloxane polymer. The cured fabric shows reduced tensile strength loss compared with a conventional amino silicone because the lower amine content does not interfere with resin crosslinking.

Shear Stability and Dilution Protocols Across Production Batches

Neat RH-NB-8368-6 is shear-thinning. Brookfield viscosity at 20 rpm is 300–800 mPa·s, and at 100 rpm the value decreases to 150–350 mPa·s. Dilution is performed by adding the emulsion to cold water at 20–30 °C under a blade agitator operating at 200–400 rpm. Reverse addition or high-shear homogenization above 800 rpm strips the nonionic emulsifier and produces visible oiling. In a 500 L preparation tank, a 20–30 g/L bath reaches visual homogeneity within 10–15 min. The recirculation line should discharge below the liquid surface; if the return nozzle is above the surface, entrained air increases apparent viscosity by 15–25 % and destabilises the foam control system. Bath temperatures above 40 °C cause the mean droplet diameter to increase from 40–80 nm to 150–300 nm, with creaming after 8 h. Under laboratory shear at 3000 rpm for 60 min, the mean droplet diameter increases by 12 % without visible coalescence. Batch preparation with softened water is preferred when water hardness exceeds 200 mg/L CaCO₃; hard water can reduce dilution stability and leave mineral deposits on the cured fabric.

When RH-NB-8368-6 Replaces Conventional Amino Silicone in Exhaust Dyeing

In exhaust application on cotton knit fabric using a jet dyeing machine with a liquor ratio of 1:8, the dose of RH-NB-8368-6 is typically 1–3 % on weight of fabric. Residual hydrogen peroxide after bleaching must be reduced below 0.5 mg/L; higher residual peroxide oxidises the amino groups and reduces softness. The treatment bath is adjusted to pH 4.5–5.0 with acetic acid and circulated at 40 °C for 10 min before product injection over 5 min. After an additional 20 min circulation, the bath turbidity reduction exceeds 90 %, indicating near-complete exhaustion. The wet fabric is hydroextracted and dried at 110–120 °C without high-temperature cure. Compared with conventional high-amine oils, the lower molecular weight of RH-NB-8368-6 provides a more even distribution in rope form and less silicone accumulation on jet machine walls. The product should not be combined with anionic optical brightening agents or alkaline softeners in the same bath; if overdyeing is required, an intermediate rinse with 0.5 g/L acetic acid is recommended. Published data for exhaust application on regenerated cellulose at doses above 5 % is limited.