Security Guard Military Navy Blue Combat Uniform 92% Nylon 8% Spandex

A synthetic fibre with high elongation at break (over 400%), low modulus and high elastic recovery. Chinese trade name for multi-block polyurethane fibres. Also known as elastane. Spandex has high elongation (500% to 700%), low modulus of elasticity (200% elongation, 0.04 to 0.12 g/dan) and high elastic recovery rate (200% elongation, 95% to 99%). The physical and mechanical properties are very similar to those of natural latex yarn, except for its greater strength. It is more resistant to chemical degradation than latex yarns and has a moderate thermal stability with a softening temperature of around 200°C or more. Most of the dyes and finishes used for synthetic and natural fibres are also suitable for the dyeing and finishing of spandex. Spandex is resistant to perspiration, seawater and various dry cleaning agents and most sunscreen oils. It will also fade with prolonged exposure to sunlight or in chlorine bleach, but the degree of fading varies greatly depending on the type of spandex.
Spandex fibres have such high elasticity because their polymer chains are made up of low melting point, amorphous 'soft' chain segments as the parent and high melting point, crystalline 'hard' chain segments embedded within them. The molecular chains of the flexible chains are cross-linked to form a certain mesh structure, which allows them to stretch freely due to the low interaction forces between the molecular chains, resulting in a large elongation performance. The molecular chains of the rigid chain segments have a greater bonding force, and the molecular chains do not elongate indefinitely, resulting in a high resilience. The cross-section of radon filaments is mostly dog-bone-shaped, while some filaments have a smooth or serrated surface. The breaking strength is the lowest among all textile fibres, only 0.44-0.88CN/dtex (the strength of the polyether type is higher than that of the polyester type). The moisture absorption range is small, generally 0.3-1.2% (compound filaments have a slightly higher moisture absorption rate than monofilaments). Heat resistance varies greatly depending on the variety, most fibres are stored for a short period of time at 90-150°C and the fibres are not damaged, the safe ironing temperature is below 150°C and can be interfered with by heating and wet washing. Dyeing performance is better, can be dyed into a variety of tonal colours, dyestuff has a strong affinity for fibres, can adapt to most varieties of dyestuffs, and has good chemical resistance, resistant to most acids and bases, chemicals, organic solvents, dry cleaning agents and bleaching agents, as well as resistance to sun and wind and snow, but not resistant to oxides, easy to make the fibres yellow and strength reduced.
Spandex is generally not used alone, but is blended into fabrics in small quantities. This fibre has both rubber and fibre properties and is mostly used in core yarns with spandex as the core yarn, called elastic core yarn. The main features of this yarn are, firstly, a good hand feel and appearance, good moisture absorption with the outer fibres made up of natural fibres; secondly, the use of only 1-10% spandex filament to produce a high quality elastic yarn; thirdly, the elasticity percentage control range from 10% to 20%, which can Different elasticity values can be selected according to the use of the product. It is easy to spin yarns of different thicknesses from 25 to 2500 denier, and is therefore widely used to make elastic knitted fabrics such as hosiery, furniture covers, skiwear, sportswear, medical fabrics, belts, munitions equipment, elastic parts of astronaut suits, etc. As new demands are made on fabrics such as light weight, comfortable fit and soft texture, low fibre spandex fabrics are taking up an increasing proportion of synthetic fabrics. Spandex is also used in bare silk and spandex twisted with other fibres, mainly for warp and weft knitted fabrics, woven fabrics and elastic fabrics.