The Characteristics Of Tencel And The Prevention And Control Of Defective Products

The characteristics of Tencel and the prevention and control of defective products

Tencel fiber has the hygroscopicity of natural fiber, the wet and dry high strength of polyester fiber, the drape of viscose fiber and the hand of silk fiber. However, there are many problems with the quality of the products at present, and the overall level is not high. Among them, the whitening color difference, the color block and the cotton grain products are more prominent; the peach skin fabric has uneven fluff; the blended interlaced monochrome The color difference of fabrics is more common; the creases, scratches, stains and other defects of thick fabrics are more serious. It is understood that these products are related to certain characteristics of Tencel fiber.

1 Tencel fiber characteristics and product analysis

1.1 Fibrillation of fiber surface

Tencel fiber has high crystallinity and uniform fiber cross section, but the fibril bond is weak and has no elasticity. If it is mechanically rubbed, the outer layer of the fiber will break and form a fur of about 1~4 microns in length, especially in the wet state. Underneath, it is more likely to be produced, and when it is serious, it will become entangled into cotton.

Fibrillation has a dual effect. Uneven local fibrillation can result in uneven product appearance, resulting in quality differences, hue differences, and cotton crepe.

The uniform production of fibrillation makes the fabric look suede, and it becomes a jean-style fabric, which also makes the denim more natural and old. Non-woven filter materials and specialty papers can also be made using fibrillated properties. It can be seen that the fibrillation problem must be artificially controlled and utilized.

1.2 Wet expansion of fiber

Tencel fibers are highly expandable and swell up to 40% in water. This imparts excellent drape and smooth motion to the fabric, but makes the fabric stiff in the wet state, especially medium to thick fabrics having a larger basis weight. Therefore, the fabric is prone to creases, scratches and stains in the dyeing and finishing and garment processing, and such defects have a strong "memory" and are preserved for a long time.

1.3 Fiber dyeability

Tencel fiber expands greatly after water contact, dyes and additives are easy to enter the fiber interior, so the initial dyeing rate is quite high, easy to cause front and back and left and right color difference. In the selection of dyes, the variety with high initial dyeing rate should be selected. The color difference is controlled by means of salt and multiple additions of alkali. Its color yield is larger than that of ordinary natural fibers; it is difficult to dye the blended and cross-woven fabrics in the same color, and strict control of the hue must be considered.

Dyeing has an effect on fibrillation, so controlling the movement of ingredients and dyes is critical. Fibrillation can be controlled by a dyeing process. Due to the presence of surface fibrillation, the dyeability may be low on the surface.

When the Tencel fiber is interwoven with the wool by the two-step method, the two fibers have a problem of mutual staining. When it is dyed with a reactive dye and a weak acid dye skein of wool blended yarn, the strength of the blended yarn is significantly reduced, which affects the weaving.

2 Control and utilization of fiber fibrillation

2.1 Selection of Tencel fiber

There are two types of Tencel fiber: the G-100 is a standard type, which is easy to produce fibrillation. A-100 type is not easy to produce fibrillation, but the strength is slightly lower than 10%. It is more suitable for ordinary dyeing and finishing process, especially suitable for knitted fabrics, but it can not produce peach skin style. Lyecell's filament fiber Newcell is said to not fibrillate and can be used to interweave with other fibers.

2.2 Effect of yarn and fabric structure on fibrillation

For yarns with high yarn twist and tight structure, the ends of the short fibers can be firmly bonded to the fabric, and the tendency to fibrillate and pilling is less in the wet treatment process. Generally, the twist factor of the ring yarn can be increased to 350~370, and the hairiness of the rotor yarn is less.

2.3 Effect of spinning process on fibrillation

The chemical fiber is generally of equal length, the short fiber rate is very low, and the yarn hairiness is much less than that of pure cotton. However, if the spinning process is improper, the short fiber rate and hairiness will increase greatly; this is the fibrillation of fabric or garment dyeing and finishing. Potential crisis. The breakage, damage, especially fine fibers of the fibers during spinning are prone to occur, which is the root cause of the increase in the ratio of short fibers and hairiness.

2.4 Effect of dyeing and finishing process on fibrillation

2.4.1 Effect of dyeing and finishing process on fibrillation

The common dyeing and finishing process of Tencel fiber fabric is as follows:

Singeing - desizing - (primary fibrillation) - removal of fibrils - dyeing - (removing fibrils, secondary fibrillation) - soft and resin finishing

Among them 1. Suitable for general smooth fabrics, which can be used without primary fibrillation and secondary fibrillation. 2. Applicable to jeanette fabrics, generally need to carry out primary fibrillation, so that the ends of the short fibers with different inner lengths of the yarns are released as much as possible, and then the fibrils are removed by enzyme treatment, and then dyed for secondary. Fibrillation to get a uniform and tidy peache style.

2.4.2 Control of fibrillation before dyeing

Singeing is the basis for eliminating fibrillation. When singeing sometimes causes wrinkles in the center of the fabric, the singeing can be carried out after desizing.

The caustic soda treatment can be added before the primary fibrillation to improve the gloss and dyeing properties of the fabric, and also to reduce the fibrillation effect of the fiber and the possibility of creases during the rope dyeing, but the Tencel fiber has poor alkali resistance. It should be treated with a low alkali cold reactor.

Fibrillation is generally achieved by the enthalpy and friction of the dyeing machine under wet conditions. The peach velvet fabric can also be obtained by mechanical pulping or gold sanding machine before or after dyeing. Chemical.

The removal of fibrils is generally solved by an enzyme treatment process, and an enzyme preparation having a better effect should be selected. 100% Tencel fabric should use acidic enzyme; Tencel and cotton, hemp blended fabric should use neutral enzyme, and all need to set the process parameters reasonably, so that the removal of fibrils is sufficient, the fabric strength decreases less.

2.4.3 Dyeing equipment and fibrillation

There are many dyeing methods for Tencel fiber fabrics. It is generally not easy to produce fibrillation and wrinkle printing by flat-width dyeing equipment (coulter dyeing machine, cold-rolled pile, padding, etc.), which is suitable for general smooth fabrics. Rope-like dyeing equipment (airflow dyeing machine, overflow dyeing machine, etc.) is prone to fibrillation and is more suitable for jeanette fabrics. Airflow dyeing machine is widely recommended in foreign countries, which can make the fabric with more sufficient friction and constantly change the contact surface; after adding the smoothing agent, it can also prevent the occurrence of creases, and can also continuously carry out the fabric fibrillation, enzyme treatment, dyeing, etc. Functions, such as finishing and drying, and loosening machine can reduce the tendency of post-processing fibrillation, making the product soft and full.

2.4.4 Dye selection and fibrillation

Tencel fabrics can be used with direct, reactive, nafto dyes, etc., but the most used are reactive dyes. If a double or triactive dye can be used to form crosslinks with the fiber molecular chain, it can reduce or prevent fibrillation during dyeing. The effect of the opposite; if the product is to be produced in a peach skin style, a single reactive dye should be used.

2.4.5 Effect of resin finishing on fibrillation

Resin finishing is the main process of post-dyeing treatment. It can reduce the swelling and anti-wrinkle effect of Tencel fiber; it can also reduce the wet hardness of the fabric and avoid the tendency of fibrillation in the future. However, the amount of the resin should not be too high, otherwise the fiber embrittlement point will be formed, and a new fibrillation phenomenon will occur, which is also disadvantageous for the long-lasting maintenance of the peach skin. By adding a softening agent such as amino silicone, the fibrillation brittleness can be reduced, the surface properties of the fabric can be improved, and the reduction in the strength of the fabric caused by the resin finishing can be compensated for.

3 Tencel fiber color difference control

The color difference of Tencel fiber blended and interwoven products is more prominent. The same color dyeing must be consistent with bicomponent fiber dyeing, consistent color and color fastness. To this end, the dyes should be carefully screened to determine the color difference between the two fibers, and the color difference of each dye with good homochromaticity should be controlled to average. When using the two-solution method, add an anti-staining agent to prevent staining. Some factories use separate fibers to dye, which can shorten the dyeing time and solve the contradiction between the two types of fiber dyeing environment, and can satisfy the rich and comprehensive color of the product. In short, it needs to adopt high color matching and dyeing technology and strict Management measures can ensure the consistency of color.

4 Prevention and treatment of defects such as creases, abrasions and stains in weaving, dyeing and finishing

4.1 Basic points to reduce defects such as creases, scratches, and spots

(1) Improving the wet expansion property of the fabric The Tencel fiber can be blended and interwoven with fibers having less water swelling property such as polyester, nylon, etc., and the warp and weft density of the fabric can be appropriately reduced.

(2) The grey cloth should minimize the defects such as the crossbar, side struts, creases and dense roads of the switch, and prevent the local stiffness and damage of the fabric.

(3) Try to use the reel packaging, no folding packaging, no rope binding, reduce indentation and creases.

(4) Reduce various physical pressures and frictions on grey fabrics, finished fabrics, and humans, and try to prevent fabric damage and puncture, nail pressing, knife cutting, etc.

(5) In order to prevent wrinkles and rubbing during dyeing and finishing, a small amount of smoothing agent and softener should be added to the injury.

(6) Using dyeing and finishing equipment with large drum diameter and low rotation speed, the fabric can move freely, reducing wrinkles and scratches caused by friction and agent pressure.

4.2 Main measures to prevent such defects during processing

(1) Use scissors instead of a knife when cutting;

(2) Do not use pins or staples when gripping, or use glue or adhesive tape for the clip;

(3) As far as possible, the garment storage or semi-product transport should be laid flat or suspended to avoid creases;

(4) The pressure of the presser foot and the adjustment of the feed dog during sewing should be confirmed.

(5) Use hot water and smoothing agent when washing, and control the quantity not to exceed 80% of the capacity, and control the temperature and time.

(6) Recommend “iron-free resin finishing” to avoid creases when ironing