This article introduced the definition and classification of non-woven fabrics and how to solve the problem of non-uniform thickness and thickness that prevails in the domestic non-woven fabrics production process at present. The basic principle of the ZNS type carding machine autoleveling device and the non-woven carding machine are introduced. The effect of the self-leveling of the link on the weight of the product.
Article keywords: Non-woven, uniform, carding machine, leveling instrument, autoleveller, grammage consistency and saving raw materials, thickness, uniformity.
I. Overview: Non-woven fabrics are fabrics that are not woven, but are tangled together with a number of barbed needles, or partially adhered together. Non-woven fabrics (also known as Non Woven, English name Non Woven) consist of oriented or random fibers. If more than polypropylene (PP material) pellets as raw materials, the high temperature melting, spinning, laying net, hot pressure coiling continuous step production. It is called cloth because of its cloth's appearance and certain properties. However, they are made on wet or dry paper making machines including chemical fibers and plant fibers under the conditions of water or air as a suspending medium, and they are called non-woven fabrics, not cloth but textiles.
Second, the production process classification
1, spunlace non-woven
Spunlacing is the process of jetting high-pressure micro-streams onto one or more layers of fiber webs to entangle the fibers together so that the web can be reinforced and have a certain amount of strength.
2, heat sealing non-woven
Thermally bonded non-woven fabric refers to a fibrous or powdery hot-melt adhesive reinforcing material added to the web, and the web is heated and melted to be cooled and consolidated into a cloth.
3, pulp air-laid non-woven fabrics
Airlaid non-woven fabrics can also be called non-dust paper, dry papermaking non-woven fabrics. It uses the air-laid technology to open the wood pulp fiber board into a single fiber state, and then uses the air flow method to agglutinate the fiber on the reticular curtain, and the fiber network is then reinforced into a cloth.
4, wet non-woven
In the wet non-woven fabric, the fiber raw material placed in an aqueous medium is opened into single fibers, and at the same time, different fiber raw materials are mixed to form a fiber suspension slurry, and the suspension slurry is transported to a network forming mechanism, and the fibers are laid in a wet state. Reinforced into cloth.
5, spunbond non-woven
Spun-bonded non-woven fabrics are laid after the polymer has been extruded and stretched to form continuous filaments, the filaments are laid into a web, and the webs are then subjected to self-adhesion, thermal bonding, chemical bonding, or mechanical reinforcement. The web becomes a non-woven fabric.
6, meltblown non-woven
The process of meltblown nonwoven fabrics: polymer feed - melt extrusion - fiber formation - fiber cooling - web formation - reinforcement into cloth.
7, acupuncture non-woven
Acupuncture non-woven fabric is a kind of dry non-woven fabric. Acupuncture non-woven fabric uses the puncture effect of a needle to reinforce the fluffy web into cloth.
8, stitching non-woven
The stitch-bonded non-woven fabric is a type of dry-laid non-woven fabric, and the stitch-bonding method uses a warp-knitted stitch structure on a web, a yarn layer, a non-woven material (such as a plastic sheet, a plastic thin metal foil, etc.) or a combination thereof. The body is reinforced to make a non-woven fabric.
Its main uses can be roughly divided into:
(1) Nonwovens for medical and sanitary use: surgical gowns, protective clothing, sterilized cloth, masks, diapers, civilian rags, wipes, wet wipes, magic towels, wipes, beauty products, sanitary napkins, and health care Pads, disposable hygiene cloths, etc.;
(2) Non-woven fabrics for home decoration: wall coverings, table cloths, bed sheets, bedspreads, etc.;
(3) Non-woven fabrics for clothing: linings, fusible interlinings, battings, styling cotton, various synthetic leather backings, etc.;
(4) Industrial nonwovens; filter materials, insulation materials, cement bags, geotextiles, and covered cloth;
(5) Non-woven fabrics for agriculture: crop protection fabrics, breeding fabrics, irrigation fabrics, insulation curtains, etc.;
(6) Other non-woven fabrics: space cotton, insulation and sound insulation materials, automobile decoration, oil absorption felt, smoke filter, tea bags, etc.
1. The manufacturing methods are roughly divided into the wet method using water (7% in Japan and 1-2% in the world) and the dry method without water (93% in Japan and 98% to 99% in the world) . Other methods include hot air or hot-pressing (thermal bonding, wire bonding, etc.) and adhesives (chemical bonding), etc.
2. Non-woven fabrics have many advantages: 1) air permeability 2) filterability 3) heat preservation 4) water absorption 5) water resistance 6) stretchability 7) no messiness 8) good hand feeling, softness 9) lightness 10) elasticity , Recoverable 11) No directionality of fabric 12) High productivity compared to woven fabric, high production speed 13) Low price, mass production, etc.
3, the disadvantages are: 1) compared with the textile cloth strength and durability is poor 2) can not be cleaned like other cloth 3) fiber arranged in a certain direction, it is easy to split from the right angle and so on. Therefore, the recent improvement in production methods is mainly aimed at preventing the improvement of division.
Second, the problems encountered in the non-woven fabric production process
Polyester cotton in the production period because of the spinning or spinning conditions, it is inevitable that some abnormal fibers, especially the use of recycled chips produced by the reclaimed cotton, more likely to produce abnormal fibers; abnormal fiber outsole can be divided into the following types;
a. Single coarse: Incompletely extending fibers, which are likely to cause abnormal dyeing, have less effect on non-woven fabrics, but are used for water-based or needle-punched fabrics used in artificial leather base fabrics. Serious impact.
b. Parallel yarn: Two or more fibers stick together after stretching. This type of fiber can easily cause abnormal dyeing. It has less effect on non-woven fabrics that do not require dyeing, but it is used for water cloths used in artificial leather base fabrics. Or acupuncture has a serious effect.
c. Colloidal: broken filaments or tangled filaments are produced during extension so that the fibers do not extend to form hard cotton. This product can be divided into a primary gel, a secondary colloid, and a tertiary jelly. After such abnormal fibers are subjected to carding, they are often deposited on the clothing cloth to cause problems such as poor mesh formation or broken nets. Such raw materials will cause serious quality defects in most of the non-woven fabric products.
d. Oil-free cotton: During the extension period, because the car is not smooth, there is no oil on the fiber during driving. This kind of fiber usually has a dry touch. In addition to causing static electricity in the non-woven production process, it also causes problems in semi-finished products after finishing. .
e. The above four kinds of abnormal fibers, single coarse and parallel filaments are more difficult to be removed during the production of non-woven fabrics. Gel-like and non-oily cotton can be removed as long as the production personnel pays a little attention and the defects of product quality are reduced.
The following factors may be responsible for the uneven thickness of the nonwoven fabric under the same processing conditions:
a, low-melting fiber and conventional fiber mixed cotton uneven: different fibers have different cohesion, in general, low-melting fiber than conventional fibers have a larger cohesion, but also less easy to disperse. If the low-melting-point fibers are unevenly dispersed, the portion having a low-melting-point fiber content is less, because a sufficient net-like structure cannot be formed, and the nonwoven fabric is relatively thin, resulting in a relatively thick phenomenon in a place having a large content of low-melting fibers.
b. Incomplete melting of the low-melting fiber: The melting of the low-melting fiber is incomplete. The main reason is that the temperature is not enough. For a nonwoven fabric with a low basis weight, the problem of insufficient temperature is usually not easily caused, but for high basis weight, high thickness The product needs special attention to whether it is enough. The non-woven fabric at the edge has enough heat, and the non-woven fabric is usually thick, and the non-woven fabric is located in the middle part, because the heat is less likely to be insufficient to form a thinner non-woven fabric.
c. High shrinkage of fibers: Regardless of conventional fibers or low-melting fibers, if the hot air shrinkage of the fibers is high, the problem of shrinkage is likely to occur due to shrinkage during the production of the nonwoven fabric.
Three, on the leveling
In summary, in the production process of non-woven fabrics, how to make the non-woven fabrics become more uniform, uniform weight, has become the most important issue facing many manufacturers. The factors that remove the difference between the equipment itself and the raw materials, a device that automatically adjusts to achieve non-woven uniformity through human intervention has been successfully launched, and is playing a vital role in some non-woven production lines!
Here are two sets of Wuxi Pratt ZNS intelligent non-woven self-leveling instrument purchased by our company to talk about the use of experience.
1. Structure: ZNS type card conditioner auto-leveling instrument adopts PLC with high-life-time speciality as control center, French Schneider frequency conversion with vector control as drive mechanism, and high-precision German brand sensors and controllers to ensure system reliability The operation of the external man-machine dialogue touch screen, online work status.
The system can be divided into three parts: detection display and control center, execution drive device, and sampling system.
2. Working principle: The whole carding machine auto-leveling system adopts computer control technology and adopts advanced data collection and communication functions, which can easily change the setting input. A few seconds of self-test after turning on the power supply immediately sample the external input. The thickness of the cotton layer is applied to the left and right sensors through the feeding roller. The sensor passes through the volume detection of the roller layer per unit time, feedbacks it to the control center, and the control center issues an instruction to the actuator. Control surface layer uneven weight and deviation, consistent with gram weight. (See attached drawing) Solving the problem of hysteresis and error in electronic weighing autoleveling, using a more scientific and more sensitive volumetric detection method.
3. Our company is Changshu Tianlong non-woven equipment, the process is: opening machine → cotton box → carding machine → lapping machine → hot air shaping machine → coiling machine. Production of spray-on cotton (imitation silk) foreign trade orders, customer requirements, the use of the original non-woven equipment, poor weight control, can not meet customer requirements. After several comparisons, Wuxi City Pratt Electromechanical ZNS Card Autoleveler was selected and modified in the original feeding section of the card. The instrument comes with a reversing function and an emergency stop function.
4. After refitting, when manually feeding 1/4 scrap, the quality comparison before and after use: weight deviation value before use is 0.5kg/volume, and the maximum deviation after use is 0.3kg/volume. Each roll design has a length of 21 meters and weighs around 8.7Kg. Even after increasing the feed of scrap, there was no change in the deviation of each roll. (Note: The above data is the average of the three months before and after self-leveling using the ZNS type carding machine).
From this calculation, after using the autoleveller, the deviation of the gram weight per square meter is within plus or minus 2 grams, and the error rate is within 4%. Not only meet customer requirements, but also adding side materials, still does not affect the quality. In this way, while controlling the weight, it saves raw materials and electricity consumption. The effect of improving quality is obvious.
Conclusion: The ZNS carding machine auto-leveling instrument is compact, simple to install, economical and practical. It is a good choice for solving the problem of uneven thickness and weight in the existing non-woven process conditions. The use of self-leveling of the ZNS carding machine eliminated the transformation of the process gears, facilitated the process on the machine, and saved the loss of raw materials to a greater degree.
ZNS type non-woven carding leveler is a hybrid ring type balancer system, which is inexpensive, effectively replaces imported equipment, and can be used for supporting acupuncture, spunlace, etc. It is applicable to the transformation of carding machines in any non-woven equipment. The market prospect is very high. broad. ![]()