Silicone Softener Classification and application

Softener that can adsorb on the surface of textile fibers and smooth the surface of the fibers to change the feel and make the product more comfortable. Among the various auxiliaries of textiles, the variety and dosage of softeners are the first, and silicone softener are a kind of softener with superior performance, outstanding effect and wide application. These softeners are emulsions or microemulsions of polysiloxanes and their derivatives, which not only give the fabric a good softness and smoothness, but also impart gloss, abrasion resistance, elasticity, antifouling and wrinkle resistance to the surface of the nonwoven fabric. The non-woven fabric has a slippery style, and this kind of material is non-toxic, does not pollute the environment, and has low cost. It has been widely used in various industries. Silicone Softener products have been developed to date, and can be classified into three types: inactive, active and reactive group modification according to the chemical reactivity and fiber reactivity of the active silicone silicone emulsion.

1. Classification and performance characteristics of Silicone Softener

Silicone Softener

1.1 Inactive Silicone Softener

Such softeners are mainly dimethyl silicone oils, called polydimethylsiloxane (DMPS), referred to as methyl silicone oil. It can impart good softness and heat resistance to fabrics, and its emulsion products include Dow Corning 36, 37 and the like. Because the degree of polymerization is not high, it can not crosslink itself, and does not react to the fiber. The texture, fastness and elasticity of the finished fabric are not ideal, so it can not be directly used as a softener, and must be prepared under the action of an emulsifier. Silicone oil emulsion can be applied to fabrics to increase washfastness, such as DIC Silicon softener 500 from Japan and Perlie SI from Bayer. Such softeners are known as first generation silicone softeners.

1.2 Active Silicone Softener

Such softeners mainly replace the two ends of the dimethyl polysiloxane (DMPS) linear structure with a hydroxyl group (-OH) or a hydroxyl group to make it hydrophilic. An emulsion made of such a terminal hydroxyl-terminated dimethylpolysiloxane, a so-called silicone hydroxy emulsion. There are quite a variety of such products, which can be used as a softener alone, or can be cross-linked with other silicones to form a water-insoluble molecular film on the fibers, so the finished fabric has a certain waterproof and washable. The results are Dow Corning 1111, Ultratex FSA from Ciba Geigy, Switzerland. Such softeners are second generation silicone softeners. According to the different surfactants used in the preparation, it can be divided into several types of cationic, anionic, nonionic and complex ions. It can be selected according to the type of fabric.

1.3 Modified Silicone Softener

These softeners introduce other reactive groups on the silicone molecular chain, which have special functions to meet the needs of high-grade finishing of various fabrics, improve the antistatic, oil and hydrophilic properties of the fabric, and make the chemical fiber fabric have Many advantages of natural fabrics have become a third-generation silicone soft finishing agent with special functions.

2. Development of modified Silicone Softener

Modified silicone softeners developed in the late 1970s, many of which have been used in the finishing of fabrics, are currently being researched and developed at home and abroad. This kind of product greatly improves the hydrophilicity, washing durability, shrinkage resistance, etc. of the fabric by introducing various reactive groups such as amino group, epoxy group, polyether, hydroxyl group and the like on the side chain of the siloxane. The group gives the fabric a different style. At present, new products that are being researched and competing at home and abroad are generally divided into three categories: reactive, including amino, epoxy, carboxyl, methacryl and fluoroalkyl; non-reactive, mainly simple Polyether modification; mixed type, such as polyether amino and epoxy modified. The most widely used in textiles is polyether modification, while softeners are more modified with amino groups. Most of the products are mixed modified, including a small amount of simple amino group, epoxy group, carboxyl group and fluoroalkyl group. Sex. The functional groups and application properties of several modified silicone softeners are shown in the table below.

2.1 Amino-modified Silicone Softener

The amino-modified silicone softener is a polysiloxane having a side chain or an end group bearing an amino group. The amino group may be a primary ammonia, a secondary ammonia, a tertiary ammonia or an ammonium salt, or may be an aromatic ammonia. The synthesis methods are bulk polymerization and emulsion polymerization. The fabric of the amino-modified silicone softener is obviously improved in elasticity, and the combination with the fiber is very strong, and has a good washing effect, so that it has a soft, smooth and full-bodied, elastic hand, and greatly improves the mechanical mechanism of the fabric. Performance, also has a certain anti-wrinkle, anti-shrinkage effect. The organosilicon with aminoethyl and aminopropyl groups in the amino-modified silicone softener has the best effect.

Amino-modified silicone softeners are easily yellowed under the influence of heat or ultraviolet rays and are therefore not suitable for soft finishing of light-colored fabrics. Currently, such softeners are still improving. The improved method is epoxidation, amidation or secondary amination, etc., to control the degree of modification or to adopt mixed modification, or to form a stable silicone microemulsion.

2.2 Epoxy modified Silicone Softener

According to the reaction type, there are mainly three methods for epoxy-modified silicone oil: hydrosilylation reaction of hydrogen-containing silicone oil with terminal alkenyl epoxy compound; octamethylcyclotetrasiloxane (D4), substituted with epoxy group Polymerization of cyclotetrasiloxane (D4) or the like; other synthetic methods such as condensation reaction of α,ω-dihydroxy silicone oil and epichlorohydrin. The epoxy group has high activity and can crosslink with groups such as hydroxyl group, amino group and carboxyl group on the surface of the fiber to form a stable chemical bond, so that the treated fabric has a durable finishing effect. The epoxy-modified silicone-treated fabric has high stability and softness, but has poor slip and water absorption. Since epoxy is basically very reactive. Therefore, the water absorption of the fabric treated with the epoxy-modified silicone can be improved by grafting a strong water-absorbing group at the end of the epoxy group.

2.3 Polyether modified Silicone Softener

The preparation of the polyether modified silicone softener can be carried out according to the mechanisms of hydrosilylation reaction, esterification reaction, Michael addition reaction, active hydrogen epoxy addition reaction, alcohol hydrogen condensation and siloxane hydrolysis condensation reaction. Technology is maturing. Because of their good suitability, biocompatibility and low glass transition temperature, these polymers have advantages that other surfactants cannot match. The introduction of a water-soluble unsaturated polyether on the side chain of the polysiloxane allows the hydrophobic silicone to be converted into a hydrophilic silicone. The fabric finished by the polyether modified silicone also has good anti-staining and antistatic properties, but the softness and the washing durability are poor. Because of its good compatibility with other finishing agents, it can also be used in the same bath as dyeing. Polyether-epoxy hybrid modified silicone combines the advantages of polyether and epoxy silicone, and at the same time makes up for their respective shortcomings. It is a multifunctional multi-component silicone finishing agent with excellent comprehensive performance.

2.4 Other modified silicone softener

2.4.1 Carboxyl modified silicone softener

In the presence of a platinum catalyst, a carboxyl group-modified silicone can be obtained by an addition reaction of an unsaturated fatty acid with a Si—H bond in a silicone. Carboxyl-modified silicone softeners are chemically reactive and polar, and can be used in natural fiber finishing to bond well with fibers and improve the antistatic and hygroscopic properties of chemical fibers. When used in combination with an amino group or an epoxy-modified silicone, it can improve the soft hand and is not easily peeled off during washing.

2.4.2 Sulfhydryl modified silicone softener

A mercapto-modified silicone can be obtained by a thiourea method or an acetic acid method. Finishing the wool with it gives the wool a durable shrink-proof and lubricity.

2.4.3 Alcohol modified silicone softener

An alcohol-modified silicone can be obtained by polar addition of an unsaturated alcohol to a Si-H bond in a silicone oil or by introducing a hydroxyl group. Such softeners improve the dyeability, heat resistance and water resistance of the fabric.

2.4.4 Ester-modified silicone softener

The ester-modified silicone softener was synthesized by emulsion polymerization using hydrogen-containing silicone oil and acrylate under the action of water-soluble catalyst. The softening agent can make the fabric soft and smooth, and has good elasticity, and is suitable for soft finishing of chemical fiber and its blended fabric with cotton.