Characteristics and Selection of Amino Silicone Oil

Jan 7, 2021

Amino silicone oil is a basic component used in textile softener. It has the best adsorption, compatibility and emulsification. Using a mixer or homogenizer, the amino silicone oil is easily emulsified into a stable and transparent microemulsion by the appropriate surfactant. It can be used alone or combined with other organosilicon or organic softeners to form a special softener, which is suitable for the softening finishing of various textiles.

Basic introduction
Amino silicone oil is a basic component used in textile softener. It has the best adsorption, compatibility and emulsification. Using a mixer or homogenizer, the amino silicone oil is easily emulsified into a stable and transparent microemulsion by the appropriate surfactant. It can be used alone or combined with other organosilicon or organic softeners to form a special softener, which is suitable for the softening finishing of various textiles. The ammonia value of amino silicone oil is between 0.2 and 1.2. The higher the ammonia value, the better the softness and smoothness, but the greater the yellowing.

characteristic
Excellent soft, smooth and even handle.
The tear strength and crease resistance of the fabric are enhanced.
Improve fabric elasticity.
Washable and dry washable.
It is easy to emulsify and can be made into a stable microemulsion.
Excellent compatibility with most organic softeners and other textile auxiliaries.

Selection
In general, according to the conventional requirements, the selection of amino silicone oil for different fabrics is as follows:
① Pure cotton, blended knitted fabrics and woven fabrics are mainly soft, and amino silicone oil with 0.6 ammonia value can be selected;
② Pure polyester fabric, mainly smooth handle, can choose 0.3 ammonia value of amino silicone oil;
③ Pure silk knits and woven fabrics are mainly smooth in handle and high in gloss. Amino silicone oil with 0.3 ammonia value is mainly selected and compounded with smoothing agent to increase luster;
④ Wool and its blended fabric should be soft, smooth and elastic, with little change of shade. For some products, the elastic value can be increased by 3.6;
⑤ Cashmere sweater, cashmere fabric, comprehensive handle is higher than wool fabric, can choose high concentration compound products;
⑥ Nylon socks, mainly smooth handle, choose high elastic amino silicone oil;
⑦ The elasticity of acrylic and spandex is the main requirement, and acrylic and spandex blended yarn can meet the requirement of high elasticity;
⑧ Ramie fabrics (flax and ramie) are mainly smooth, and amino silicone oil with 0.3 ammonia value is the main choice;
⑨ The soft handle of rayon and artificial cotton is the main, and the amino silicone oil with 0.6 ammonia value can be selected;
⑩ In order to improve the hydrophilicity of polyester alkali reducing fabric, polyether modified silicone oil (CGF) can be selected. CGF is made by hydrosilylation of methyl hydrogenated silicone oil with polyethylene glycol, polypropylene glycol and other polyether with unsaturated bond at the end. The new polyether modified silicone oil introduced reactive epoxy groups on the silica chain, which improved the handle and durability of the fabric.

Amino silicone oil softener can increase the softness of fiber materials. The softener with excellent performance can also make the fiber obtain special handle, endow the product with different finishing styles, improve the quality grade and added value, and increase the comfort of clothing. The softeners used in industry can be divided into four types according to their main active components: oil type, surfactant type, reactive type and polymer type. The softeners used in the early days were mainly the first three types. In the 1970s, the development and use of polymer softeners quickly attracted people's attention and became the mainstream of softening finishing. Among the series of polymer softeners, silicone softener (mainly composed of polysiloxane) has the best performance and the largest output. According to statistics, there are about 150000 tons of siloxanes used as textile finishing auxiliaries in the world, of which softeners account for 70% ~ 80%.

Polyether silicone oil
Polyether silicone oil is a kind of silicone oil with polyoxyethylene or polyoxypropylene or fatty alcohol polyoxyethylene polyoxypropylene ether groups attached to the carbon atoms of the side chain. It is developed to improve the shear stability of silicone emulsion and poor moisture absorption of finished fabric during the use of the first and second generation silicone softeners. It can be prepared by addition reaction of hydrogenated silicone oil and unsaturated polyether catalyzed by platinum catalyst, ring opening reaction of epoxy silicone oil and polyether, or esterification reaction of alcohol hydroxyl modified silicone oil with bifunctional carboxylic acid and polyether [10,11]. After introducing hydrophilic polyether group into the side chain, the hydrophilicity of silicone oil increases, and even changes from hydrophobicity to water solubility. Therefore, there will be no demulsification and oil bleaching problems during the use of polyether modified silicone oil. Secondly, the introduction of polyether group also increases the hygroscopicity, antistatic and easy decontamination of the finished fiber or fabric, so polyether silicone oil is widely used in cosmetics and shampoo. However, the self crosslinking ability of polyether silicone oil and its binding ability with fiber are weak. This problem can be solved by introducing or retaining some epoxy groups in the main chain of silicone oil. For example, silicone oil [11] with structure (I) not only has all the advantages of polyether silicone oil, but also has the characteristics of softness, crease resistance, washability and strong wool feeling. So polyether / epoxy silicone oil is a kind of active silicone softener with the largest dosage and the best effect before the development of cationic amino silicone softener.

Performance characteristics
Structural features
From the structure point of view, polysiloxane has the following characteristics: (1) the main chain Si-O-Si bond is inorganic structure, and the side chain is organic group, so it is a kind of typical semi inorganic and semi organic polymer. (2) The bond angle (∠ siosi) of Si-O-Si bond on the main chain is 130 ° to 145 ° and the bond length of Si-O bond is 0.163 nm to 0.164 nm. The bond energy is 367.8 kJ / mol. Compared with the polyoxyalkanes, the bond length of the polyoxyalkanes is 1427.4kmol/108, the bond energy of the polyoxyalkanes is higher than that of the polyoxyalkanes. (3) The bond angle of the side chain C-Si-O is 160 ° and the length of the c-Si bond is 0.188 nm. Therefore, the activation energy required for the rotation of the side chain methyl around the Si-O bond is low, only 8 kJ / mol. (4) The interaction between dipoles and dipoles of Si-O bonds in the main chain of polysiloxane and the interaction between Si-CH3 in the side chain of polysiloxane makes the polysiloxane molecules only exist with methyl group outward and silicon oxygen bonds inward in a certain α helix structure. This unique structure leads to small chain to chain interaction, large molar volume and low surface tension. (5) Polysiloxanes with Si-H bond, Si or or Si OH group have reactivity.

Performance characteristics
Polyorganosiloxane has the following characteristics: (1) good electrical insulation, flame retardancy and weather resistance; (2) ideal physiological and chemical inertia, no toxicity and ecological environment pollution; (3) low glass transition temperature, good high and low temperature resistance, low viscosity temperature rheology; (4) easy spreading, film forming, defoaming, hydrophobicity and lubricity caused by low surface tension. In addition, the modified silicone oil formed by the substitution of some methyl groups of polydimethylsiloxane by other organic groups such as polyether group, epoxy group, alcohol hydroxyl group, sulfhydryl group, carboxyl group, phosphate group, amino group or fluoroalkyl group has not only the above general properties, but also the additional properties given by these organic groups. Therefore, polyorganosiloxane emulsion can be used for fabric finishing, not only can effectively isolate fiber, avoid direct contact between fiber and fiber, but also reduce the friction coefficient of fiber surface, and make the fiber easier to slide relative to show softness. Polyorganosiloxane emulsion finishing fabric has the following advantages: (1) comfortable handle, ideal soft, slippery, elastic, good performance; excellent wrinkle resistance and drapability; (2) certain resistance to water and good air permeability; (3) fabric anti friction, tear strength increased, and sewing ability enhanced; (4) blended / chemical fiber fabric has Imitation cotton, linen, imitation wool or silk like effect; (5) The size of cotton, hemp, wool, silk and other fabrics is stable and the shrinkage resistance is improved.

Development history
The development history of silicone softener can be traced back to 1940s. As early as 1940, people tried to impregnate fabrics with dimethyldichlorosilane in order to obtain some waterproof effect [2]. However, dimethyldichlorosilane will release hydrogen chloride gas which is harmful to human body and fabric. In 1945, people impregnated the fabric with the alkaline solution of sodium methylsiloxane. It was found that the fabric after weak acid treatment and drying at 110 ° C ~ 120 ° C had good waterproof effect, but the high alkaline solution had adverse effects on the fabric [3]. Therefore, the above two technologies are not adopted by the textile industry. After the presence of hydrogenated silicone oil in 50s, researchers at Dow Corning [4] finished the fabric with hydrogen silicone oil emulsion and obtained good waterproof effect. However, the waterproof film formed by hydrogen silicone oil on the fabric surface is hard, brittle and easy to fall off. When methyl silicone emulsion and hydrogen silicone emulsion are added, the waterproof film is soft and has a good handle. This is a practical discovery, which has aroused people's interest in silicone as a fabric softener. In recent 50 years, the development of polysiloxane, especially the appearance of reactive and functional polysiloxane, has made silicone softener colorful, which is widely used in many aspects such as fiber and fabric softening finishing, spinning finish, hair conditioner and household detergent