High Concentrated Wool Soft Finishing Agent RH-NB-56G

High Concentrated Wool Soft Finishing Agent RH-NB-56G is supplied as a high-active aqueous dispersion for handle modification of wool and wool-rich textiles. The product code RH-NB-56G denotes a concentrated formulation in which the active-matter content is substantially above that of conventional softener emulsions, which commonly contain 10%–15 wt% solids. Incoming material typically falls within a class-typical active-matter interval of 25%–45 wt%, but the binding lot value must be taken from the supplier’s certificate of analysis and used to calculate the volumetric dosing rate. The product is diluted with demineralized process water before introduction into the finishing bath; dilution ratios in the range 1:5 to 1:10 are applied in dyehouses to prevent localized high-viscosity zones and emulsion shock inside circulation pumps. The concentrate is not a hand-wash additive, and direct metering into acidic dye baths without pre-dilution is not a recognized use pattern in production-scale wool processing.

What incoming inspection parameters guard against lot-to-lot handle variation?

Because high-concentrate wool softeners are susceptible to phase separation during storage and transport, an incoming inspection matrix is applied before plant release. The product is a pumpable off-white to pale-yellow dispersion; gross pink, grey, or clear separation indicates either microbiological contamination or freeze-thaw damage and warrants rejection. The pH of a 1% aqueous dilution is commonly maintained between 4.5 and 6.5 when measured with a calibrated electrode according to ISO 3071. Viscosity at 25 °C is evaluated using a Brookfield LVT rotational viscometer with spindle 3 at 30 rpm; class-typical values fall between 500 mPa·s and 2000 mPa·s, although high-concentrate products may show higher values at low temperature. Density at 20 °C is checked by a pycnometer or oscillating U-tube method based on ISO 2811-3; the acceptance window of 0.98 g/cm³ to 1.06 g/cm³ is used to detect formulation dilution or solvent contamination. The product must disperse in cold water without visible coagulum when 10 mL is added to 90 mL of demineralized water at 15 °C under gentle stirring at 100 rpm. Storage stability is typically specified as 6–12 months in closed containers at 5 °C to 35 °C; freezing and direct steam trace heating are not permitted. Where the supplier’s certificate of analysis does not state a method, the values given above are class-typical reference points and must not replace lot-specific release data.

In exhaustion processing on wool knitgoods and wool/polyamide blends, RH-NB-56G is applied after the final rinse and neutralization stage. The bath is set at 35 °C to 45 °C and adjusted to pH 4.5–5.5 with dilute acetic acid before the softener is added. Typical application levels are 1.0%–3.0% on weight of fibre in overflow or soft-flow machines operating at liquor ratios from 1:8 to 1:15. Circulation is maintained for 15–20 min; after that interval, further gains in softening are usually marginal and the fabric may begin to acquire surface deposits at rope fold points. Padding application on open-width wool fabric uses a two-roll or three-roll horizontal mangle with a nominal squeeze pressure of 2.0 bar to 3.5 bar; the bath concentration is calculated from the liquor pickup, generally in the range 10 g/L to 30 g/L, depending on dry pickup and handle target. The padded fabric is dried on a stenter with a fabric temperature not exceeding 120 °C for wool, because higher temperatures may initiate yellowing and alter the wool fibre’s moisture regain. If the wool has been carbonized or anti-set treated, a preliminary compatibility trial at 0.5% addition is performed before bulk treatment. Because published data for this specific formulation in all wool qualities is limited, the optimum addition level is established through a statistically designed handle assessment under mill-specific machine conditions rather than transferred from generic textile softener tables.

In soft-flow units with centrifugal circulation pumps, the diluted product is preferably injected into the side-tank rather than the main pump suction to avoid high impeller shear. The circulation pump should be run at a speed that provides sufficient bath turnover without causing stable foam; measured liquor turnover in production machines is typically in the range 2–4 bath volumes per minute, and lower turnover may produce uneven deposition on dense wool packages. If fabric is processed as garments, a rotary drum machine with a cylinder diameter of 1.2 m to 1.6 m and a speed of 8–12 rpm is used with the same pH and temperature settings, but the softener is added through a recirculation line after complete bath wetting. The product’s dispersion stability under shear can be evaluated in the laboratory with a mechanical stirrer at 500 rpm for 30 min; visible creaming or sediment above 2 mL per 100 mL indicates unsuitable batch condition.

A critical threshold exists between softening development and finish build-up on wool fibre surfaces

On wool, the level of cationic or pseudo-cationic adsorption is limited by the available cuticle cell surface charge and the specific surface area of the fibre assembly. At addition levels above 3.0% o.w.f., surplus softener is not bound to the fibre, but remains in the bath or deposits as a local film during drying. This leads to a measurable increase in extractable matter, which is evaluated gravimetrically after Soxhlet extraction with dichloromethane according to ISO 4045 or by an internal finished-fabric extraction procedure. The threshold is not fixed across all wool qualities: fine merino tops with high surface area can accept slightly higher addition than coarse carpet wool, and heavily mechanically processed knits may exhibit higher uptake due to surface abrasion and scale lifting. The processing window for an acceptable handle-to-deposit ratio is therefore narrower than the simple dosage range suggests, typically requiring confirmation runs at 1.0%, 2.0%, and 3.0% o.w.f. before bulk production. In winch equipment with low liquor turbulence, uneven circulation near the fabric rope can produce streak marks if the concentrate is not pre-diluted; this effect is more pronounced at bath temperatures below 30 °C, where emulsion viscosity increases and distribution is slower. The product should therefore be introduced through a side-tank dilution line with a dosing pump set to a stroke rate below the rated maximum to avoid cavitation in the pump head.

Finish build-up also affects downstream fabric performance. A laboratory evaluation can include bending length measured according to ISO 7698 or an equivalent ring-loop stiffness test; the bend length of treated wool may decrease by 5%–15% relative to untreated fabric at the optimum addition, but values can plateau or increase slightly when surface deposits restrict fibre movement. The same effect is monitored through extractable matter and through woven fabric handle panel rankings. In blended wool/polyamide outerwear, the finish should not reduce seam tensile properties below the mill’s internal limit; destructive tensile testing may follow ISO 13935-2 for seam strength and ISO 13934-1 for strip tensile strength. Because RH-NB-56G is a finishing auxiliary and not a reactive crosslinker, the durability of the softened handle is primarily governed by interfacial adhesion and film wash-fastness; where repeated commercial laundering is specified, the treated fabric is washed according to ISO 6330 and the handle reassessed after 1 and 5 wash cycles. Published data for this specific formulation in multi-cycle laundering is limited, so mill trials are required for warranty-grade claims.

Compared with conventional low-solids wool softener emulsions, the high-concentrate form reduces the mass and volume of chemical stored per unit of finished fabric. This difference changes the warehouse footprint and the dosing pump calibration: a standard softener at 12 wt% solids may require 20 kg per batch, whereas a 35 wt% concentrate requires approximately 7 kg per batch at equivalent active matter. The lower water content also reduces the probability of microbial spoilage, provided the concentrate is not stored in partially filled containers for more than 30 days. Compared with amino-functional silicone macroemulsions, RH-NB-56G is typically positioned as a wool-specific softener with reduced yellowing tendency on white and pastel shades; however, the exact yellowing index after heat exposure must be verified per lot because amine content and emulsion stabilizer chemistry control this behavior. The product’s ionic character is selected to minimize interference with acid-milling dyes and acid levelling agents; nevertheless, a clean rinse before the finishing bath is maintained to avoid coacervation with residual anionic dyes.

Compatibility limits with anionic wool auxiliaries and high-temperature drying

The product must not be mixed directly with concentrated anionic optical brightening agents, naphthalene sulfonate dispersants, or strong anionic detergents in the same stock tank, because coacervation and filter-clogging precipitates may form. In exhaustion applications, the wool substrate should be thoroughly rinsed after dyeing or bleaching until the residual bath conductivity is below 200 µS/cm and the rinse water is visually clear. The bath is then acidified with acetic acid to pH 4.5–5.5 before the softener is introduced. The use of hard water with calcium hardness above 150 mg/L CaCO₃ may reduce dispersion stability and should be corrected with a suitable sequestrant in the dilution water rather than in the softener concentrate itself. Drying and curing temperatures above 130 °C are not recommended for wool goods treated with RH-NB-56G, because heat-induced yellowing and the formation of hydrophobic surface films can occur. The product should not be applied simultaneously with oxidative anti-chlorination or shrink-resist treatments that have active chlorine residues. If resin finishing is required, the softener is applied after resin curing or in a separate bath, depending on the resin system’s catalyst and pH. Regulatory compliance for textile auxiliaries should be verified against the supplier’s declaration for REACH, ZDHC MRSL, and Oeko-Tex Standard 100; RH-NB-56G must be included in the mill’s chemical inventory and in the finished-goods restricted substance checklist before export.

In continuous plants with reprocessing loops, returned bath liquor should not be reused without monitoring accumulated electrolyte and dye liquor carry-over, because both can reduce the dispersion cloud point and alter adsorption kinetics. When the finishing bath is reused over multiple cycles, the concentration of residual dyehouse salt should be kept below 2 g/L expressed as sodium chloride, and the bath should be filtered through a 25 µm screen to remove fibre debris before the next dosing cycle. The product’s high-concentrate nature means that overdosing errors are amplified; therefore, the dosing line should be calibrated gravimetrically at the start of each batch, and any change in bulk density or viscosity should trigger recalibration of the volumetric pump. If the product has been stored for more than 30 days after the container is opened, it should be gently homogenized by low-shear mixing and visually inspected before use; high-shear mixing should be avoided because it can split the internal phase and reduce the product’s deposition uniformity on wool.