1. Overview of Textiles
(1) Meaning of textiles
Textile refers to single yarn, plied yarn, worsted yarn, yarn, rope, woven fabric, knitted fabric, knitted fabric, all kinds of textile reproduction products, felt blanket, non-woven fabric, etc., which can be directly applied or further processed.
(2) Ecological textiles
1. Meaning: Ecological textiles refer to those textile products which are made of materials that are harmless to the surrounding environment or less harmful to human health. This type of textile is toxicologically tested and bears the corresponding mark, i.e. manufacturers, distributors and textile associations and their member bodies, with specific certification in accordance with the Oeko-Tex Standard 100 system and requirements. Those who meet the requirements will be issued with a specific certificate and a specific label. The validity period of the certificate is one year.
2. Conditions: production ecology, consumption ecology, processing ecology and supervision of the whole process
2. The textile fiber
(1) Concept and characteristics
Fiber is a natural or synthetic filamentous material, textile fiber refers to the fiber used to process textile cloth.
Textile fiber characteristics: textile fiber has a certain length, fineness, elasticity, strength and other good physical properties. It also has good chemical stability. For example, natural fibers such as Cotton, Wool, Silk, and Line are ideal textile fibers.
(2) Classification and identification
Different kinds of textile fibers can be identified by sensory method, combustion method, microscope method, dissolution method, drug coloring method and infrared spectrum method. Identification usually requires qualitative and quantitative analysis. Usually, the following steps are used for identification:
First determine the type of fiber (natural fiber or chemical fiber) by combustion or sensory method
If it is a natural fiber, the microscope can be used to distinguish between plant fiber and animal fiber. If it is a chemical fiber, the combination of fiber melting point, specific gravity, refractive index, solubility and other aspects of the difference is distinguished one by one.
In the identification of blended fibers and blended yarns, it is generally possible to identify the presence of several fibers under microscope and then identify each one by appropriate methods.
For dyed or finished fibers, it is usually necessary to carry out staining and stripping or other appropriate pretreatment to ensure reliable identification results.
3. Textile yarn
(1) Main technical indexes of yarn
Yarn quality depends on the quality of raw materials and process quality, the quality of yarn directly affects the appearance and use value of the fabric, the main indicators to measure the quality of yarn include yarn fineness and uniformity, strength and extension, twist and twist direction, etc.
The yarn thickness and evenness
Yarns are divided into thickness, which means the quality of the yarn and its length of the relationship. It is usually expressed in terms of fixed repetition and fixed length. Fixed weight is the length of a yarn of a given weight, while fixed length is the weight of a yarn of a given length.
Yarn count, a measure of yarn thickness, often used to measure the thickness of spun yarns made from short fibers. It has metric numbers (metric) and imperial numbers (imperial).
Metric count (Nm) : The number of meters of length that a gram of yarn (silk) has. Formula: Nm = L/G
NE: The number of 840 yards of yarn in one pound (453.6 g). Formula: NE = L/ (G×840)
The yarn count is indicated by a number. The larger the number, the longer the yarn length, and the finer it will be. On the contrary, the thicker the yarn. In addition, the yarns are represented by two sets of numbers. The first set of numbers represents the number of individual yarns and the second set of numbers represents the number of roots of the ply. If 16S/1 represents sixteen single yarn; 32S/2 represents thirty-two double strands. Generally speaking, the finer and more uniform the yarn, the lighter and smoother the fabric after weaving, and the lighter the weight of the garment, and vice versa.
② Strength and elongation
The tensile strength of a yarn is called strength, and the stronger the yarn, the stronger the fabric, all other things being equal. The strength of a single yarn is measured on a single yarn strength tester. The strength of the yarn is expressed by the weight of the broken yarn in grams or kilograms. When the yarn is stretched by external force, elongation deformation occurs. The percentage of the yarn's stretching length to the original length under a certain load is called the yarn's elongation. Yarn should have a proper stretch to make the yarn elastic and flexible. If the stretch is too large, the yarn will relax and reduce the strength. Stretch too small can increase the strength of the yarn, but make the fabric harden.
The twist and direction of the yarn
(2) Common indicators of textile yarn quality
The quality of textile yarn can be judged according to the relevant national standards. Usually can also be from the uniformity of yarn thickness, defects (such as impurities, cotton knots) and other appearance for intuitive judgment.
② knot number. Refers to the number of globular nodules entangled on 1 gram of cotton yarn fiber. Cotton knots are hazardous yarn defects.
Article 3. The dry. It is the degree of uniformity of thickness (or quality) along the length of the yarn, also known as evenness of thread. The evenness of yarn is an important index of yarn quality. Good evenness, uniform yarn thickness, good quality; Otherwise, it is poor.
(4) hairiness. It is mainly aimed at staple yarn. Because the fiber is short, after spinning into yarn, the end of the fiber exposes the outside of the yarn, forming plush on the surface of the yarn. Hair is also a defect in the yarn and is usually removed by singeing.
5. Thick section. Coarse yarn is the yarn in the direction of length, thicker than the normal yarn segment, divided into short and thick (under 15mm) and long and thick.
Those details. In contrast to a snag, details are smaller than normal yarn segments along the length of the yarn. Detail is a point in the yarn that affects the strength of the fabric.
6 twist. The twist is the number of twists within the specified length of the yarn. Twist is commonly used in staple yarns and is expressed in two ways, namely, twist per 10cm and twist per inch (also expressed in this way for ply yarns). Yarns and filaments are expressed by the number of twists in lm.
His strength. Is the force required to break a unit of yarn. Strength is a term used to describe whether a yarn is strong or not.