Hydroentanglement Bonding Process for Production of Nonwoven Fabric
Mohamed Abdel-Zaher El-Sharkawy1
Amany Omar Abdel-Rahman
Dept. of Textile Engineering
Alexandria University, Egypt
Hydroentanglement is a technique for mechanically bonding loses filaments or fibers arranged in the web. The efficiency with which the web is entangled depends on the peculiar properties of laminar high-speed water jet used. In this project, a prototype of hydroentanglement bonding machine has been designed and manufactured to study the properties of the produced nonwoven and the factors affecting on the efficiency and fabric properties.
Hydro-entangling, spun lacing, hydraulic entanglement and water jet needling are synonymous terms describing the process of bonding fibers (or filaments) in a web by means of high-velocity water jets. The oldest technique for consolidating fibers in a web is mechanical bonding, which entangles the fibers to give strength to the web. Spun-lacing uses high-speed jets of water to strike a web so that the fibers knot about one another.
The interaction of the energized water with fibers in the web and the support surface increases the fiber entanglement and induces displacement and rearrangement of fiber segments in the web. In addition to mechanical bonding, structural patterns, apertures and complex three-dimensional effects are produced if required by the selection of appropriate support surfaces. Hydro-entanglement also provides a convenient method of mechanically combining two or more webs to produce multilayer fabrics.
Geo-textiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geo-textile fabrics come in three basic forms: woven (looks like mail bag sacking), needle punched (looks like felt), or heat bonded (looks like ironed felt).
Geotextile composites have been introduced and products such as geo-grids and meshes have been developed.
Overall, these materials are referred to as geo-synthetics and each configuration geo-nets, geo-grids and others-can yield benefits in geotechnical and environmental engineering design.
To use geo-textiles to reinforce a steep slope, two components have to be calculated:
- The tension required for equilibrium
- The appropriate layout of the geo-textile reinforcement.
REVIEW OF LITERATURE
In textile industry, nonwoven industry is organized differently and separately from the traditional woven or knitting industry. Nonwovens are engineered fabrics, and have higher production rate, larger availability, and lower cost than traditional woven and knitting fabrics. So, in many industries nonwoven fabrics are replacing the traditional fabrics.
Today’s nonwovens are highly engineered solutions made up of a variety of materials including fibers, powders, particles, adhesive, films and other materials that provide a multitude of functionalities, such as hospital supplies, hygiene applications, horticultural applications, consumer products, interlinings, geo-textiles, carpet backings, automotive parts, filters, wipes, etc..
The steps for producing nonwoven fabrics include: web formation, web entanglement, web drying and optional further treatments. Fibers or polymers are first processed to form webs. There are several processes to produce webs, such as dry-laid, wet-laid, air-laid, spun-bonding, and melt-blowing process. Then webs are bonded to produce nonwoven fabric through the bonding processes, such as needle punching, hydro-entangling, thermal, and chemical adhesive bonding.
2.2. Methodology of non-woven
Nonwoven emerged from the textile, paper and plastic industries and has, for over 40 years, evolved into a distinct industry. As the demand for non-woven has steadily increased, it has been met by the technology and ingenuity of raw materials and equipment suppliers, and non-woven producers and converters. The production of non-woven can be described as taking place in three stages, although modern technology allows an overlapping of some stages, and in some cases all three stages can take place at the same time .
At non-woven technology, we have three main stages to produce the fabric and they are as followed:
2.2.1 Web formation:
There are a lot of methods to form a web like:
- Dry laid.
- Card laid.
- Air laid.
- Spun melt laid: Like (spun laid- melt laid)
- Wet laid.
- Other technologies: Like (electro static spinning-flash spun)
2.2.2 Web bonding:
Web bonding is chosen according to the end use and followed applications. So, there are many types of bonding like:
- Stitch /bonding.
2.2.3 Finishing treatment:
The opportunity to combine different raw materials and different techniques accounts for the diversity of the industry and its products. This diversity is enhanced by the ability to engineer nonwovens to have specific properties and to perform specific tasks .
Principle of producing non-woven fabric:
Nonwovens are typically manufactured by putting small fibers together in the form of a sheet or web (similar to paper on a paper machine), and then binding them either mechanically (as in the case of felt, by interlocking them with serrated needles such that the inter-fiber friction results in a stronger fabric), with an adhesive, or thermally (by applying binder (in the form of powder, paste, or polymer melt) and melting the binder onto the web by increasing temperature) .
2.3. Hydroentanglement process
Hydroentanglement is a mechanical bonding process designed to produce nonwoven fabrics with texture and appearance that resemble woven and knitted fabrics.
In a typical hydroentanglement process, a row or multiple rows of highly pressurized, fine, closely spaced water jets impinge on a fiber web which is supported by forming wires. Due to the impact of water jets, fibers from the surface are inserted into the fibrous web, and fibers are displaced and rotated around other fibers that surround them, resulting in fibers twisting and entangling around the neighboring fibers. The fabric produced is held together by the fiber-to-fiber friction [3, 4].
Fibers are carded in the carding machine and entangled in the hydro-entangling unit. After hydro-entanglement, the water in the fabrics is removed through the drying process. There is a finishing process if desired, and the fabrics are then wound on rolls for future processing.
2.4. Methodology of hydroentanglement
Spun-lacing is a process of entangling a web of loose fibers on a porous belt or moving perforated or patterned screen to form a sheet structure by subjecting the fibers to multiple rows of fine high-pressure jets of water. Various steps are of importance in the hydro-entangling process [5, 6].
While some of them are typical in a nonwoven process, some of them are unique to the process of spun-lacing. The steps characteristic for producing hydro-entangled nonwoven fabric include:
- Precursor web formation
- Web entanglement
- Water circulation
- Web drying
The formed web (usually air-laid or wet-laid, but sometimes spun bond or melt-blown, etc.) is first compacted and pre-wetted to eliminate air pockets and then water-needled. The water pressure generally increases from the first to the last injectors which are used to direct the water jets onto the web.
This pressure is sufficient for most nonwoven fibers, although higher pressures are used in specialized applications. It has been argued that 10 rows of injectors (five from each side of the fabric) should achieve complete fabric bonding .
Injector hole diameters range from 100-120 µm and the holes are arranged in rows with 3-5 mm spacing, with one row containing 30-80 holes per 25 mm .
The impinging of the water jets on the web causes the entanglement of fibers. The jets exhaust most of the kinetic energy primarily in rearranging fibers within the web and, secondly, in rebounding against the substrates, dissipating energy to the fibers.
A vacuum within the roll removes used water from the product, preventing flooding of the product and reduction in the effectiveness of the jets to move the fibers and cause entanglement.
Usually, hydroentanglement is applied on both sides in a step-wise manner. As described in the literature , the first entanglement roll acts on the first side a number of times in order to impart to the web the desired amount of bonding and strength.
The web then passes over a second entanglement roll in a reverse direction in order to treat and, thereby, consolidate the other side of the fabric. The hydro-entangled product is then passed through a dewatering device where excess water is removed and the fabric is dried.
Hydro-entanglement carried out at standard conditions (six manifolds of needles, 1500 psi, and web weighing 68 g/m2) requires 800 pounds of water per pound of product .
For that reason, it is necessary to develop a new filtration system able to effectively supply clean water with this high throughput; otherwise, water jet holes become clogged. This system consists of three stages: chemical mixing and flocculation, dissolved air flotation and sand filtration . Spun-laced fabrics have led to a lot of speculation regarding their manufacture because most of the manufacturing process details are considered as proprietary .
2.5. Materials used in hydroentanglement
As previously mentioned, hydroentanglement could be carried out using dry-laid (carded or air-laid) or wet-laid webs as a precursor. Most commonly, precursors are mixtures of cellulose and man-made fibers (PET, nylon, acrylics, Kevlar, etc).
In addition, we can use very fine fibers produced from split table composite fibers to produce hydro-entangled substrates for synthetic suede leather products.
In general, cellulosic fibers are preferred for their high strength, pliability, plastic deformation resistance and water insolubility. Cellulosic fibers are hydrophilic, chemically stable and relatively colorless. Another advantage is that cellulose has an inherent bonding ability caused by a high content of hydroxyl groups, which attract water molecules. As the water evaporates from the fabric, the hydroxyl groups on fiber surface link together by hydrogen bonds .
Influence of cotton micronaire on fabric properties has been studied. Generally, low micronaire cotton is not recommended for hydro-entangled nonwovens because of higher number of neps and small bundles of entangled fibers, resulting in unsightly appearing fabric.
In spite of this, fabrics made with lower micronaire fiber show higher strength, probably caused by a higher number of fine fibers and greater surface area .
In addition, greige cotton has been used in spun-lacing technology. It has been shown that the absorbency rate increases with increasing hydro-entangling energy. This is the result of oil and wax removal from the fiber surface. These nonwovens can be subsequently bleached, which should raise the strength of the fabric .
2.6. Machine components
2.6.1 Web support system:
The web support system plays an important part in most nonwoven processes. Especially for the spun-lace process, it has a critical role in this process because the pattern of the final fabric is a direct function of the conveyor wire. By special design for the wire, we can have following varied products :
- Ribbed and terry cloth-like products
- Aperture products
- Lace patterns or company logo can be entangled into fabrics
- Production of composites
In fact, the surface characteristics of the forming wire determine what the nonwoven products will look like. A smooth top surface of forming wire is desired for little or no marking. As for the aperture product, there is a high knuckle in the forming wire. A high knuckle in the wire will give a large hole in the fabric since the high-pressure water jets are deflected by the high knuckle .
2.6.2. The hydroentanglement unit:
Hydroentanglement is an energy transfer process where the system provides high energy to water jets and then transfers the energy to the precursor. In other words, the energy is delivered to the web by the water needles produced by the injector. Therefore, we can calculate the energy from the combination of the water velocity (related to the water pressure) and the water flow rate (related to the diameter of the needles) .
2.6.3 Water system:
As we know, water is most critical part in spun-lace process. Therefore, there are some requirements for the water as follows :
- Large amount of water – about 606 m3/hr/m/injector for 40 bar and 120m m
- Nearly neutral pH
- Low in metallic ions such as Ca No bacteria or other organic materials
2.6.4 Filtration system:
Due to the large amount of water consumed, the spun-lace process requires that it be recycled. Therefore, a high-quality filtration system is necessary for the spun-lace process. Some of special filters are listed as following :
- Cartridge filter
- Sand filter
- Bag filter
2.6.5 Web drying:
When the fabric leaves the entanglement zone the web, it is completely saturated with water. There are a few steps to remove water from the fabric. They include :
2.6.6 Vacuum dewatering system
In general, the diameter of water needle ranges from 100 to 170 m. The highest number of needles is 1666 needles per meter of injector, corresponding to the smaller diameter. The water pressure ranges from 30 bars to 250 bars and it is increased stepwise from injector to injector.
2.7. Parameters affecting the product performance properties
Both the fiber and web properties have primary effects on the performance of the finished product. These parameters comprise of the web material and area basis-weight, and the way in which the web was manufactured. As mentioned in literature , spun-laced technology demands a high-quality web, especially in its uniformity and isotropic orientation.
The process variables are considered to have secondary effects on the performance of the finished product. The supporting substrate transport is an important variable influencing the fabric.
There are two systems of entanglement substrate systems: flat and rotary. For the most part , there is no difference in the mechanism used to achieve entanglement. The rotary concept uses a compact machine design with ease of sheet run that provides entanglement of both sides of the web. Entanglement is nearly achieved with as little as four meters (in the machine direction) of the material. Sometimes the fibers are driven through the substrate wire and, in the flat concept, it is seen that the wire (along with the fibers) is dragged over the suction box causing difficulty in the removal of the product. In the rotary concept, this problem is not encountered because the fibers are not pulled along the machine direction. Substrate texture seems to have important influence on the product. The size of perforations is usually measured in “mesh”, which is the count of wires per inch of the substrate. It has been shown  that imposing the same energy into two webs with different substrate meshes; the finer substrate yielded a stronger product resulting from finer support. The coarser wire support (20 meshes) gave a bulkier product with more permeability, but with less strength. Water removal from the fabric was shown to be dependent on the mesh of the support belt. The lower the mesh, the more energy that was necessary to remove the remaining water. In addition to that, the surface of the fabric can be aperture (textured on the surface) with a specially structured substrate .
The amount of energy delivered in the web is a crucial parameter influencing the fabric structure and properties since
Water pressure is another parameter related to fabric energy intake. There are several water pressure levels used .
Another basic process parameter having influence on the fabric is the speed of the line. If a constant amount of energy is being delivered to a fabric, the speed of the fabric determines how much energy is going to be absorbed per fabric unit area. Logically, the higher the line speeds, the less the energy that is absorbed by the fabric and the lower the fabric strength that is achieved.
Now, higher water pressure machines are mostly used since using high pressure, energy can be delivered into a web with less water needles and less water. This is economically more useful .
2.8. Water flow and nozzle characteristics
The underlying mechanism in hydro-entanglement is exposure of fibers to a non-uniform spatial pressure field created by a successive bank of high velocity water jets. The impact of these water jets with the fibers, while they are in contact with their neighbors, displaces and rotates them with respect to their neighbors. During these relative displacements, some of the fibers twist around others and/or interlock with them due to frictional forces. The final outcome is a highly compressed and uniform fabric sheet of entangled fibers. Since its infancy, hydro-entangling has shown promise for the textile industry.
The uniformity of the product and the repeatability of the hydro-entangling process require a continuous and locally uniform jet-fabric impact.
Water jets are known to break up somewhere downstream of the nozzle due to the interfacial forces between them and the surrounding air. A number of parameters, including nozzle internal flow patterns resulting from cavitation and/or wall friction, influence the behavior of the water jets.
Conventional hydro-entangling orifice nozzles have geometries that consist of a conical part and a capillary section.
The study of simulation and characterization of water flows inside hydro-entangling orifices employed a two-phase numerical simulation to make a comparison between the cone-up and the cone-down orifice nozzle geometries used in hydro-entangling.
The conclusion was that the cone-down configuration has a lower discharge coefficient than its cone-up counterpart. Therefore, a water jet discharged from a cone-down orifice has a slightly smaller diameter than that of a cone-up.
The cone- down configuration has a velocity coefficient slightly larger that of the cone-up configuration because the wall friction is higher in the cone-up geometry. The cone-down geometry forces the water to separate from the metallic walls once it enters the capillary.
This prevents cavitation, which is known to shorten the intact length of the water jet. The air gap between the water and the metal surface extends the lifetime of the orifice.
In the following Figure an orifice with the cone-up version is demonstrated to facilitate interpretation on the comments being made on this section.
The cavitation and hydraulic flip study (Vahedi Tafreshi and Pourdeyhimi 2004) reported that Hydroentangling owes its success to the peculiar properties of coherent water jets.
For Hydro-entangling to be feasible at higher pressures, it is extremely important that water jets maintain their collimation (a straight line) for an appreciable distance downstream of the nozzle.
The discussions were regarding cavitation and its irregular and unsteady phenomena nature.
A realistic picture of cavitation can be described as an irregular, cyclic process of bubble formation, growth, filling (by water), and break-off.
In an actual water jet, a vapor cloud after formation and growth will be carried downstream, another cloud will form in its place, and the process will repeat. However, if the cavitation cloud reaches the nozzle outlet, the ambient air will be sucked into the nozzle and cavitation will stop (hydraulic flip).
2.9. Characteristics of geo-textiles
There are three main properties which are required and specified for a geo-textile are its mechanical responses, filtration ability and chemical resistance. These are the properties that produce the required working effect. They are all developed from the combination of the physical form of the polymer fibers, their textile construction and the polymer chemical characteristics.
For example, the mechanical response of a geo-textile will depend upon the orientation and regularity of the fibers as well as the type of polymer from which it is made.
Also, the chemical resistance of a geo-textile will depend upon the size of the individual component fibers in the fabric, as well as their chemical composition – fine fibers with a large specific surface area are subject to more rapid chemical attack than coarse fibers of the same polymer. The Characteristics of Geo-textiles are broadly classified as:
1. Physical properties:
- Weight – thickness
- Stiffness – density
2. Mechanical properties:
- Tenacity – tensile strength
- Drapability – compatibility
- Flexibility – tearing strength
3. Hydraulic properties:
- Porosity – permeability – Permittivity
2.10. Features and benefits of hydroentanglement
The hydroentanglement process yields the most textile-like product of any of the current processes for producing nonwoven fabrics. Hydroentanglement holds the promise of delivering a soft feel and comfort with a hand similar to those of woven and knits at the economics of nonwovens. Hydro-entangled fabrics have the following characteristics:
- Soft, limp, flexible hand
- High absorbency
- High drape
- High bulk
- Comfortable and moldable
- Low linting
- Stretchable without loss in thickness
- High strength without binders
- De-lamination resistance
Hydroentanglement is a highly versatile process  because it can be used to produce nonwovens with a broad range of end-use properties.
These differences are achieved because of a wide range of fibers that are available and because of the broad range of possible parameter adjustments.
The versatility of the hydroentanglement processes is seen as an advantage because this process can be used to combine conventionally formed webs with melt blown, spun-bond webs, paper, other textiles and scrims in order to get a combination of properties that cannot be achieved by the use of a single web.
Spun-lace fabrics can be further finished, usually dyed and/or printed, treated with binders to allow for wash durability, or fire retardants can be applied to resist burning. The fabric can be treated by antimicrobial agents to enhance resistance against microorganisms.
Hydro-entangled non-woven, depending upon the fibers processed, are strong, soft and pliable and can be dense or open and are typically absorbent. So, they are mostly used for fine fiber webs intended for the medical, personal care, baby care and consumer and hygiene markets.
THE AIM OF THE WORK
In this study, we aim to give an idea about one of most important methods for producing non-woven fabrics which is hydroentanglement process.
A prototype machine will be designed and manufactured to represent the process of hydroentanglement.
As well as, some important tests have been carried out to show the properties of textiles used in geo-textile application of non-woven which can be produced on hydroentanglement machine.
The important properties to be investigated are; Tensile strength, puncture strength, water permeability, equivalent opening size and tearing strength.
THE DESIGN OF MACHINE
As the name implies the process depends on jets of water working at very high pressures through jet orifices with very small diameters. A very fine jet of this sort is liable to break up into droplets, particularly if there is any turbulence in the water passing through the orifice. If droplets are formed the energy in the jet stream will still be roughly the same, but it will spread over a much larger area of batt so that the energy per unit area will be much less. Consequently, the design of the jet to avoid turbulence and to produce a needle-like stream of water is critical. The jets are arranged in banks and the batt is passed continuously under the jets held up by a perforated screen which removes most of the water. Exactly what happens to the batt underneath the jets is not known, but it is clear that fiber ends become twisted together or entangled by the turbulence in the water after it has hit the batt. It is also known that the supporting screen is vital to the process; changing the screen with all other variables remaining constant will profoundly alter the fabric produced.
Although the machines have higher throughputs compared with most bonding systems, and particularly compared with a needle loom, they are still very expensive and require a lot of power, which is also expensive. The other considerable problem lies in supplying clean water to the jets at the correct pH and temperature. Large quantities of water are needed, so recycling is necessary, but the water picks up air bubbles, bits of fiber and fiber lubricant/fiber finish in passing through the process and it is necessary to remove everything before recycling. It is said that this filtration process is more difficult than running the rest of the machine.
4.2. The Hydroentanglement prototype:
The machine consists of two main units:
- The Derive unit
- The Hydroentanglement unit
The drive unit consists of:
1. Pump with high pressure up to 150 pars:
The pump is the heart of the water jet system. The pump pressurizes the water and delivers it discontinuously and has ability to turn that pressurized water into a supersonic water jet stream.
Table (1) Specification of the pump
|RPM||Model||Flow (l/min)||Pressure (bar)||Power (kw)||Weight|
|1450||PNC 09/17 S||9.0||170||2.9||5.3||S = Male Shaft 24mm|
2. Motor to drive the pump:
|RPM: 1750||Thermal Protection: On request|
|Voltage: 230V||Enclosure: TEFC|
|Phase: 1||Service Factor: 1.0|
|Hertz: 60||Frame: H112|
|Full Load Amps: 23||Bearings: KBC 3606ZZ/1pcs|
|Weight: 66 lbs|
The pump and the motor were connected by using (KE’ SERIES ELASTOMERIC COUPLINGS). General purpose flexible coupling, excellent transmission capacities, are simple to be installed with low maintenance requirements.
Slots have been made in the coupling from two sides by using (vertical milling machine) . From the side of the motor this slot is with dimension (8*4) and from the side of the pump with dimension (8*3).
And after that the coupling had been putted between the pump and the motor but there was a problem that the axes height of the pump is lower than the axes height of the motor and this will cause faults during working and will lead to damage the motor or the pump so four circular legs with ( 3 mm diameter and height 8 mm ) have been made , this legs make the two parts in the same level and after that we put them on a steel plate with dimension ( 75*35*10 ) and the plate is putted on a base and is fixed with the base by using electrical welding .
This has been made in the Military Mill no 10.
4.2.1. Laser Cutting Process:
The laser cutting process uses a focused laser beam and assists gas to sever metallic plate with high accuracy and exceptional process reliability. The laser beam is generated by a resonator, and delivered through the cutting nozzle via a system of mirrors .
The advantages of laser technology:
Laser technology has the following advantages:
- High accuracy.
- Excellent cut quality.
- High processing speed.
- Small kerf.
- Very small heat-affected zone compared to other thermal cutting processes.
- Very low application of heat, therefore minimum shrinkage of the cut material.
- It is possible to cut complex geometrical shapes, small holes, and beveled parts.
- Cutting and marking with the same tool.
- Cuts many types of materials.
- No contact between the material and machining tool (focusing head) and therefore no force is applied to the work-piece.
- Easy and fast control of the laser power over a wide range (1-100%) enables a power reduction on tight or narrow curves
- The oxide layer is very thin and easily removed with laser torch cutting
- High-pressure laser cutting with nitrogen enables oxide-free cutting
Principles of Laser Cutting:
Most laser cutting is carried out using CO2 or Nd: YA Glasers. The general principles of cutting are similar for both types of laser although CO2 lasers dominate the market for reasons, which will be discussed later in the paper.
A laser beam delivery system is shown below, consisting of:
- CO2 laser resonator
- Rear mirror
- Gas excitation generates single wavelength light
- Output mirror
- Polarizing mirror
- Telescope mirror
- Beam bender
- Machine gantry
- Constant beam length carriage
- Beam bender
- Beam bender
- Cutting carriage
- Beam bender
- Adaptive mirror
- Focusing mirror
- Cutting head
- Cutting nozzle
The focusing device consists of either a zinc-selenide lens or a parabolic mirror which brings the laser beam to a focus at a single point. Depending on the laser beam power, a power density of more than 107 W/cm2 is achieved at the focus point. The focal length gives the distance of the focal point from the focusing optics.
The focal point is positioned above, on or below the material surface according to the requirements of the material. The high-power density results in rapid heating, melting and partial or complete vaporization of the material. The gas flowing from the cutting nozzle removes the molten mass from the kerf.
The machine moves the cutting head over the metal sheet according to the programmed contour, cutting the work-piece from the sheet.
4.2.2. The Hydro-entanglement unit:
It is a box made of stainless steel as it does not readily corrode, rust or stain with water as ordinary steel does, and we use two grades from stainless steel (316 & 304).
The manifold of Hydroentanglement prototype (bases of the box) is made from 316L stainless steel (300*300*6mm) in as it is more resistant to general corrosion and pitting than conventional nickel chromium stainless steels such as 302-304. It has the following characteristics :
- Higher creep resistance
- Excellent formability.
- Rupture and tensile strength at high temperatures
- Corrosion and pitting resistance
The manifold contains Hydro-entangling water jets which are with diameter 3mm and the nozzle-to-nozzle distance (spacing between water jets) is 8 mm.
The number of water jets nozzles has been calculated according to the following equations:
Flow rate = P½ x D2 x N x 2572 x 10-8 m3/ hour/ injector/ meter
Energy = P3/2 x D2 x N x 7 x 10-10 KWH/ injector/ meter
- P= water pressure (bar)
- D=hole diameter (mm)
- N= number of holes (per injector per meter)
The number of water jets was calculated to be 444 nozzles on the plate area of (200*200). These nozzles have been fabricated by using Laser cutting with nitrogen so we use 316L stainless steel due to the previous properties but any other material changed when is subjected to Laser Cutting machine.
The box which contains the water is made from stainless steel 304 (20*20*4) the four corners of the box are welded by using Gas Tungsten Arc Welding (GTAW) is frequently referred to as TIG welding [weldih].
IG Welding Benefits:
- Superior quality welds
- Welds can be made with or without filler metal
- Precise control of welding variables (heat)
- Free of spate
- Low distortion
And after we the box is made it is welded with the manifold and there is space 3 cm between the first manifold and the second manifold, this space is done by putting 6 Iron bushing .
In the space the fiber passes and subject to the water pressure which is passes vertical on the fiber causing entangling between fibers.
We but the Hydro-entanglement unit on a box to collect water in it and we return this water to the tank (source of water) by using water pump
Finally, the pump had connected to the Hydro-entanglement unit and to the water tank as shown in following figure:
In this chapter, the experiments of geo-textile fabrics; to define some important properties required, will be investigated.
Geo-textiles should fulfill certain requirements to permit material exchange between air and soil, it must allow rain water to penetrate the soil from outside and also excess water to drain out of the earth without erosion of the soil.
5.2. Experimental procedure
In this work, tests are applied to recognize the mechanical and hydraulic properties for three different samples with different weights and compare those properties for the three samples.
5.2.1. Material of geo-textile:
Geo-textiles mainly are made of poly propylene, polyester, poly(ethylene), poly(amide), poly vinylidene chloride or fiber glass. The samples that will be tested from polyester and they are needle punched.
5.2.2. Testing procedures and apparatus
The following properties will be examined:
22.214.171.124. Fabric thickness
This test was done on fabric thickness
126.96.36.199 Fabric weight
The Samples are prepared by using a template (10*10) cm2 to cut the sample. The testing for the samples was done according to ASTM D3776.
- The test has been done at the testing laboratory on Textile Engineering department – Faculty of Engineering.
- The fabric weight per unit area is on the scale measured in grams per Square meter.
- The results reported for the average of the samples.
188.8.131.52. Fabric grab tensile strength
The Samples are prepared by dimensions of (1 inch*12inch). The testing is done according to ASTM D5034. The test is done at the testing laboratory on Textile Engineering department – Faculty of engineering. The test is applied by two methods in machine direction and cross machine direction. The results reported from the average of the samples (3samples for each code) and for both directions.
184.108.40.206. Fabric tear strength (single rip by tongue)
The Samples are prepared with dimensions of (7cm*15 cm) or (3inch*12 inch). the test is done according to ASTM D2261 (standard tearing strength by single rip by tongue). The results reported from the average of the samples as 3 samples for each code.
220.127.116.11. Puncture tear strength
The samples are prepared with dimension of a circle with a diameter of (5cm). the test is done at the testing laboratory on Textile engineering department –Faculty of Engineering. The test is done as per ASTM D3786. The results reported as the average of the samples (3 samples for each code).
18.104.22.168. Water permeability
The samples diameter is (25cm). the test is done as per ASTM D583. The test is done at the Testing laboratory on Textile Engineering Department –Faculty of Engineering. The results reported the average of samples (3samples for each code).
22.214.171.124. Apparent opening size (equivalent opening size)
The test is done as per ASTM D4751and done at the testing laboratory on Textile Engineering Department –Faculty of Engineering. A geo-textile specimen is placed in a sieve frame, and sand beads are placed on the sample surface. ss tester at the testing laboratory on Textile department –faculty of engineering. The testing of the samples was done as per ASTM D1777 (standard test method for fabric thickness) At measuring range (0-10 mm) and the results reported is the average of applied number of samples.
5.3 Experimental methodology
In this part, we talk about the procedures followed in each experiment of mentioned tests.
5.3.1 Fabric thickness test
The experiment is done as following procedures:
- The fabric sample that is to be measured is kept on an anvil.
- The press foot is gently lowered on to the specimen.
- The reading is taken to get the thickness of the specimen.
- The flat circular indenter of the micrometer exerts the specified pressure on the fabric sample.
- The above procedure is repeated to obtain the values of thickness at least at 3 different locations.
- The mean value of all the readings of thickness determined to the nearest 0.01m is calculated and the result is the average thickness of the sample under test.
5.3.2 Fabric weight test
The procedures of test are as followed:
- Cut the fabric sample according to the template area. By this way we cut samples.
- Then these samples will be weighed by digital balance in grams.
- By this way we get the weight in gram per one square meter fabric.
- Now find out the average of these found weights.
5.3.3 Fabric tensile strength
The test procedures are as followed:
- Prepare the machine. Clamps should be set about 3 inches apart
- Select the force range of the testing machine for the break to occur between 10-90% of full-scale force.
- Set the testing machine for a loading rate as specified.
- Mount the specimen in the clamps as straight as possible so that the same lengthwise yarns are gripped by both clamps
- If specimen clips in the jaws, or breaks at the edge or in the jaws or performs markedly below the average for the set of specimens, discard the result and take another specimen.
Figure (5.6): shape of tensile test samples
5.3.4 Tear strength test
The test is done according to the following procedures:
- Secure the specimen in the clamp jaws with the slit edge of each tongue centered in such a manner that the originally adjacent cut edges of the tongues form a straight line joining the centers of the clamps and the two tongues present opposite faces of the fabric to the operator.
- Start the machine and record the tearing force on the recording device. The tearing force may increase to a simple maximum value, or may show several maxima and minima.
- After the crosshead has moved to produce of fabric tear, as indicated for the type fabric and tearing action observed. Stop the crosshead motion after a total tear or the fabric has torn completely, and return the crosshead to its starting position.
- Record if the tear occurs crosswise to the direction of applied force.
- Remove the tested specimen and continue specimens testing.
Figure (5.7): Shape of samples of tear test
5.3.5 Puncture strength (burst strength)
The experiment is done as followed:
- Place the sample in the ring clamp as flat as possible with no wrinkle or tension and tighten the clamp.
- Center the ball on the sample and set the assembly CBR machine.
- Operate the machine at top speed until the fabric is ruptured by the steel ball.
- Read and record the bursting forces and get the av
Figure (5.8): Shape of samples of puncture test
5.3.6 Water permeability (water repellent)
The procedures of this test are:
- Fasten the test specimen securely in the hoop so that the face of the test specimen will be exposed to the water flow. The surface of the specimen should be smooth and without wrinkles. Place the hoop on the stand of the tester with the specimen in such a position that center of the flow pattern coincides with the center of the hoop.
- Pour distilled water into the funnel of the tester and allow it to onto the test specimen for 25 to 30 seconds. Take the hoop by the bottom edge and tap the opposite edge firmly once against a solid object with the fabric facing the object.
- Repeat the procedure above for other 2 specimens. Record the reads and take the average value.
5.3.7 Apparent opening size (AOS)
The test is done as followed and these all procedures are done according to the standard:
- Put the sample and fix it in the frame, then apply anti-static spray uniformly on the geo-textile surface.
- Secure the sample without wrinkle and must not be stretched.
- Prepare many sizes of sand beads to use in the test and start with the smallest diameter and apply it on the center of the sample.
- Place a cover and a pan, before shaking the frame with the sample for 10 min.
- Place the sand beads still on the surface and weigh them and weigh the beads passed through the sample.
- By determination of the weight of beads passed and still on the surface and comparing with the original weight of beads, we calculate the apparent opening size. Repeat the experiment with larger diameters of sand beads and get the average to have the final value.
RESULTS & DISCUSSION
After the experiments we have done on the geo-textile fabric, we find that the effect of weight change on fabric mechanical and filtration properties (hydraulic).
Weight of the fabric is an indicator of mechanical performance only within specific groups of textiles, but not between one type of construction and another.
Therefore, it is impossible to use weight alone as a criterion in specifying textiles for civil engineering use. However, in combination of specified factors, weight is a useful indication of the kind of product for a particular purpose.
1. Fabric thickness
- sample weight 200
- sample weight 400
- sample weight 600
2. Fabric weight
3. Grab tensile strength
At machine direction
|Tensile strength (kgf)||7.64||35.02||71.74|
At cross machine direction
|Tensile strength (kgf)||13.98||30.18||45.84|
4. Tensile strength or breaking strength
- As it is universally to describe the strength of the fabric and show the load at break and elongation at break.
- At tensile strength, sample code3 with weight 600 gives the highest strength in both cases (machine direction-cross machine direction) and at the same time it gives the lowest value of elongation.
- But, sample code 1with weight 200 gives the lowest strength and the highest elongation.
5. Tear strength
|Tear strength (kgf)||23||56.3||58.3|
|Puncture strength (kgf)||24.58||32.14||33.66|
***Tear and puncture strength
- It gives a simulation for working conditions fabric.
- At tear strength and puncture strength, due to fiber in cohesion the fabric strength is produced. So, sample code 3 with weight 600 gives the highest value of both and sample code1with weight 200 gives the lowest value of both.
7. Water permeability
|Water head (cm)||15.67||14.67||20.67|
- It can vary immensely as it depends on the fabric construction.
- And it is necessary that water should flow freely through the geo-textile and prevent from unnecessary pressure.
8. Apparent opening size
***Apparent (equivalent) opening size
It gives an indication of the amount and size of particles which can pass through the fabric during usage.
At water permeability and apparent opening size, sample 200 can easily pass any particles and water due to its high porosity, but sample 600 is difficult to let particles or water to flow through it.
From the results, we can see that the effect of weight of three different samples and the change happened in different properties. The meaning of changing weight is changing in fabric construction and this change the fabric properties.
In case of weight increase, the number of fibers increase and the friction between them too. This, in fact gives variable values for each sample.
In this project, we study two parts and they are:
- Hydro-entanglement machine for bonding non-woven.
- Experiments and testing geo-textiles.
At the beginning, let’s talk about hydroentanglement machine and its versatility in products and its applications. As the most important stage during manufacturing this machine is its design, especially water jets and its influence on fabric properties.
So, we can summarize the main parameters in its design as followed:
Parameters of water jets:
- Density of jets: 10 – 30 jets/cm
- Jet diameter: 80 – 800 mm
- Pressure inside the jet manifold:
- up to 60 MPa for web bonding (Fleissner)
- up to 25 MPa for web patterning (Perfojet)
- Velocity of water jet: 10 – 350 m/sec
Also, we should notice the importance of filtration system to increase the life span of jets and the system should contain:
Typical water purification system has following stages:
- air separator,
- coarse filter, fine filter
- de-ionization unit,
- heat exchanger,
- bacteria filter.
About the second part, the tests of geotextiles and to show the effect of increasing the fabric weight on the mechanical and part of hydroluic properties.
We found that the properties increase with weight increase.
Geo-textiles are used in civil engineering earthworks to reinforce vertical and steep banks of soil, to construct firm bases for temporary and permanent roads and highways, to line ground drains, so that the soil filters itself and prevents soil from filling up the drainpipes and to prevent erosion behind rock and stone facing on river banks and the coast. They have been developed since the mid-1970s, but the advent of knitted and composite fabrics has led to a revival in attempts to improve textile construction in a designed fashion. Better physical properties can be achieved by using more than one fabric and by utilizing the best features of each.
- Pourdeyhimi B. (2005) Introducing to nonwovens, Lecture Notes of Introduction Nonwoven Products and Processes, North Carolina State University, NC.
- Medeiros F. J. (1997) Spun-lacing offers Utmost Versatility, American Textiles International, and November: 34-36.
- The Nonwovens Handbook (1988) INDA, Association of the Nonwoven Fabrics Industry.
- Vuillaume, Andre M.: A Global Approach to the Economics and End Product Quality of Spunlace Nonwovens, Tappi Journal, v.74, Aug ’91, 149-152.
- White, C. F.: Hydro-entanglement Technology Applied to Wet Formed and Other Precursor Webs, TAPPI Nonwovens Conference, 1990, 177-187
- Jaussaud, Jean Paul: Rotary hydraulic Entanglement Technology, Nonwovens in Medical and Healthcare Applications Conference, Nov 10th -12th 1987, Brighton, England.
- Allen, Charles H., Jr.: New Development for Spun-lacing Cotton, Paper presented at Fiber Society Conference, University of Tennessee, and Knoxville 19th-21st Oct. 1997
- Widen, Christian B.: Forming Fabrics for Spunlace Applications, Tappi Journal, v.74, May ’91, 149-153
- Information brochure for Hydro-entanglement technology from Valmet Paper Machinery, Honeycomb Systems Inc.
- (Hsu-Yeh Huang & Xiao GAO) M. G. Kamathq, Atul Dahiya, Raghavendra R. Hegde. SPUNLACE (HYDROENTANGLEMENT)
- Spunlace Non-woven” Perfojet, December 1991
- ” The study on the mechanical properties of spun-laced nonwoven” 16th polymer symposium Vol.9, PP 433-436.
- Christian B. Widen, “Forming fabrics for spun-lace applications” TAPPI Journal, May 1991 un.1993,
- Connolly, T.J., Parent, L.R.: Influence of Specific Energy on the Properties of Hydro-entangled Nonwoven Fabrics, Tappi Journal, v.76, Aug ’93, 135-141
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