Silicone softeners

Although fabrics made from microfibres generally have a softer handle and better drape than those from conventional fibres, these properties can be further improved to a significant extent by the application of silicone softeners, the best results being obtained with aminofunctional polysiloxanes [491]. 

The environmental compatibility of silicone softeners is generally favourable [495,496]. The discussion here concerns only the silicone component of the formulation and not the supporting emulsifying system. For the most part this is nonionic, preferably based on linear ethoxylated fatty alcohols, although alkylphenol ethoxylates are still used in some countries [496]. The salient points regarding the environmental influence of silicones can be summarised as follows ... 

Parvinzadeh, M. and Hajiraissi, R. (2008) Effect of nano and micro emulsion silicone softeners on properties of polyester fibers. Tenside Surfactants Detergents, 45 (5), 254-257. 

Non-ionic and cationic examples of silicone softeners are shown in Fig. 3.6. They provide very high sofmess, special unique hand, high lubricity, good sewability. 

Depending on their method of synthesis, silicone softeners can contain variable amounts of volatile siloxane oligomers. Together with volatile emulsifiers these oligomers can cause pollution problems in the waste air from tenter frames." In textile finishing, silicones are also used as water repellents, elastomeric finishes, coatings and as defoamers. 

Deeper colour, darker black Finishes with silicone softeners or elastomerics... 

Permanent antistatic fmishes, based on crosshnked polyamines and polyglycols, need an alkaline catalyst. Therefore the one-bath combination with finishes, which need acid catalysis, is difficult but not impossible. Examples of acid-catalysed fmishes are the easy-care and durable press fmishes, durable hydrophylic silicone softeners and elastomeric finishes, also fluorocarbon-based repellency and some flame-retardant finishes. High finish effects result from a two-bath application with of the easy-care finish first followed by the surface-related antistatic finish. 

Fatty acld/amlne and silicone softener blend. 

Replaces silicone softeners to reduce finishing costs. 

Silicone Softener/Resin Extender for Durable Press Fabrics ... 

Cationic, silicone softener for cotton and polyester/cotton yarns and fabrics. 

Permanent, reactive silicone softener. Provides a unique hand to all fabrics. Renders ring spun hand to open-end spun yarn. 

Economical silicone softener for cotton and synthetics. Imparts excellent softness while aiding fabric rewetting. Provides drape and suppleness to heavyweight fabrics such as denims and corduroys. 

In many instances silicone softening agents are also used in durable press finish formulations in combination with crease-resistant resins and than are distinguished by a substantial improvement in the mechanical properties of the textiles in addition to the softer handle. 

Summary A structure concept for durable hydrophilic silicone softeners is outlined. ABC-triblock copolymers forming polyloop polyquatemary structures were found to be very substantive on cotton fibers. A study on the adsorption kinetics suggests a two-step process (1) rapid coverage of the fiber surface, and (2) slow diffusion/spreading into the interior of the fiber. Washing experiments and subsequent evaluations of the soft hand prove the durability of the finish. XPS data indicate that after five washing cycles 60 to 70% of the new durable hydrophilic softeners remain on the fibers. For nondurable hydrophilic softeners a maximum substantive portion ranging from 20 to 40% was determined. 

An in-depth understanding of the adsorption mechanism is the key for the optimization of silicone softener structures, the subsequent softener formulation, and the adjustment of process parameters. 

Scheme 1. Silicon content on a cotton fiber, treatment with silicone softener at 40 and 60 °C, 0 to 1200, XPS...

Scheme 2. Concentration of fluorescently labeled silicone softener in aqueous phase treatment at 30,40 and 60 C,...

Fig. 4. Cross section of cotton fibers treated with fluorescently labeled silicone softener left after 30 s treatment, right after 600 s treatment, 40x magnification.

This durability of the new silicone softeners on cotton fibers has been quantified by means of XPS immediately after file finishing process and after repeated washing cycles in file presence of anionic detergents (Scheme 3). 

Burcovel. [Burlington Chem.] Softener and lubricant for cotton and pdyester/ cotton blends replacernem for silicone softeners. 

Elastosoft 89. [Reilly-Whiteman] Silicone softener fix textiles. 

Magnasoft . [Union Caibide] Silicone softeners fn textiles. 

Sandopermc ME. [Sandoz] Amino fun nal silicone softener to con-tinutxis and exhaust applies. 

TetrasQMAL. [Reilly-Whiieman] Silicone softener for textiles. 

---