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Fabric response to hydroentangling process variables is usually presented as a plot of energy consumed / kg of fabric produced. This paper presents a simple mechanical model describing the transformation of a random fiber web into a hydroentangled fabric having a clearly defined cellular structure dependent on the forming wire. The model indicates that only a tiny fraction of the energy supplied by the entangling jets is consumed in the production of the fabric. Low speed hydroentangling data for nylon 66, polyethylene terephthalate (PET), polypropylene terephthalate (PTT), and polypropylene (PP) fibers using very different forming wires indicate that force acting on the fiber, not energy, is the important variable.

Meltblown nonwovens have been produced as 2D web structures for a variety of end uses. Investigation into the development of 3D structures has resulted in a parametric evaluation of the process and its effects on the structural properties of the webs (fiber diameter, fiber orientation, and pore size distributions). The interrelationships between these structural parameters have been explored and a statistical model developed. SAS was used to develop the correlations between the structural parameters of the web. The pore diameter is found to be directly proportional to the fiber diameter and inversely related to the web anisotropy parameter. The relationship that was established for the 2D webs correlates to the relationship developed for the 3D web structures.

Meltblown nonwovens have been produced as 2D web structures for a variety of end uses. Investigation into the development of 3D structures, has led to the integration of meltblown and robotic technology to form the Robotic Fiber Assembly and Control System. The effect of curvature of the collecting surface on the structural properties of the webs such as the diameter and orientation distributions of the fibers and the pore size distribution on the webs has been investigated. The relative frequency of fibers oriented in the machine direction increased significantly when the curvature of the collecting surface increased, while the average pore size of the web decreases due to the increased orientation of fibers in the direction of collection.

The performance of four different fiber types processed at two different carding speeds of 85 and 120 m/min, under fixed operating conditions, was assessed. The totally novel approach of fixing the fiber diameter was used in the experiments. To serve this purpose, we designed four different fibers. In addition, we fixed the number of fibers per unit area of the carded web so as to create constant carding conditions for all experimental fibers. The fixed number of fibers per unit area was achieved by carding the same number of fibers per unit time for a given speed. We took samples from different parts of the card and analyzed them in order to enumerate the effect of fiber type on cardability. Fiberweb uniformity was regarded as a key parameter for assessing the cardability. Several other web and fiber parameters were measured in order to augment the understanding of the role of fiber type in high-speed carding. In general, data revealed that fiberweb uniformity did not significantly differ among fiber types at the two carding speeds 85 m/min and 120 m/min.

The main goal of this study is to investigate the performance behavior of hydroentangled nonwoven fabrics in terms of input water jet energy and fabric structural parameters (basis weight and fiber orientation). The input jet energy was varied by altering jet pressure, number of passes, process speed and fabric basis weight. To achieve the goal, two sets of trials, which had different jet pressures, process speeds, basis weights and number of passes, were executed to reveal the significance of these parameters in achieving high fabric tensile strength. Image analysis was used to determine the fiber orientation of the hydroentangled nonwoven fabrics to aid in understanding fabric performance behavior.

In previous publication, the influence of process parameters on the fiber orientation of the meltblown web was evaluated [4]. The meltblown webs were formed using Robotic Fiber Assembly and Control System (RFACS), which is described in previous publications [3, 4]. In this paper, parametric studies evaluating the effect of polymer throughput rate, attenuating air pressure and temperature, and die temperature, on fiber diameter distributions of meltblown webs from polypropylene produced by RFACS are reported. Fiber diameters were determined by analyzing fabric images obtained through scanning electron microscopy (SEM). Under the specific conditions explored, the fraction of fibers of diameter smaller than 10 microns (μm) can increase by 72% with a 7.9 × 10−2 g/min/hole (82%) reduction in throughput. A 54% increase of the same can be observed with a 2.8 bar (400%) increase in attenuating air pressure. A change of 45°C (16 %) in air temperature is shown not to significantly affect fiber diameters produced, while an increase of 67°C (26%) in die temperatures can result in an increase of 17% in the fraction of fibers of diameter smaller than 10μm. All fiber diameter distributions are shown to be unique to the condition evaluated as no overlap across distributions for changes in a given parameter is observed. Further fiber fraction smaller than 10 μm data is also shown to be unique to each parameter evaluated.

We recently reported on a co-occurrence-based method for texture analysis. This paper uses this texture analysis method to examine the development of the texture during hydroentangling as a function process conditions. We report on the development of texture as a function of hydroentangling energy. Energy was varied by controlling the pressure and number of passes. All fabrics were produced using the same web on the same forming belt substrate. Our preliminary data indicate that the degree of texture definition increases as a function of pressure up to a point and then begins to deteriorate.

The paper is reporting an extensive experimental investigation to optimize the processing of microfibers on a flat top card. Carding parameters, type of fiber finish and their interactions were studied in terms of their impact on web quality. The web quality was determined by assessing the nep content and fiber breakage due to carding. Statistical analyses of the data indicate that fiber finish and processing parameters can be selected to minimize neps and fiber breakage during carding. Furthermore the investigation showed that there is a strong correlation between the incidents of neps and the increase in short fiber content during carding. An additional finding of this study is that the generation of neps was not uniform across the width of the carded web and is influenced by fiber load measured on the doffer in the cross machine direction.

The one-dimensional characteristic of yarn has resulted in very little attention being given to the uniformity of carded web in the cross machine direction. The development of nonwovens has prompted researchers to reconsider the importance of cross machine uniformity in determining the total uniformity of the carded web. It is therefore important to develop manual and online techniques to quantify cross machine uniformity at both the input and output of the card. At the card input, uniformity is taken as representing both mass and openness characteristics of the feed matt. While at the card output, there are many available techniques that allow the on-line measurement of the mass uniformity of the carded web, determination of uniformity at the input level is more difficult. The approach that was taken was to use an off-line technique to find the mass and openness of the feed matt at different locations across the card. While traditionally mass as a property has been given a lot of importance, much less attention has been given to the concept of openness. This is due in part to the difficulty in quantifying openness. Openness is believed to have great significance in determining the overall quality of the carded web, especially with regard to the formation of neps. In order to make the concept of openness more clear, it was found necessary to develop a way of quantifying it. This was done by performing a compression test on the feed matt, and then fitting the compression data with an exponential curve. The coefficient of the exponent was used to represent openness. This approach was used to find the effect of the feed roller (pin type) on cross machine uniformity. It was found that the squeezing of the feed roller did not have an effect in redistributing the mass of the feed matt, but did have an effect in changing the openness of the feed matt. Because of the difficulty involved in the handling of the feed matt, a newly developed technique is suggested to characterize openness. While this method still relies on the compression characteristics of the feed matt, it is more appropriate because it is performed on-line. Preliminary results are reported. It was found that thickness measurement under carefully selected pressure value could be used to characterize openness precisely.

A novel system that forms two-dimensional (2D) structures on a rotating drum and three-dimensional (3D) structures on 3D molds through proper integration of a laboratory scale meltblown unit with a small die and six-axis robot is briefly described. The system advantages over traditional systems are demonstrated. Parametric studies evaluating the effect of take-up speed, die-to-collector-distance (DCD), polymer throughput rate, and attenuating air pressure on the fiber orientation distribution functions (ODFs) of 2D structures formed by the system are reported. An additional new parameter termed “fiber-stream approach-angle” is introduced and its impact on the ODF of 2D structures is also reported. Under the experimental range studied, the ODFs were significantly impacted by the parameters studied. The fiber-stream approach angle showed the highest impact, among the parameter studied, on the ODF.

The significance of a recently developed system that measures dynamic forces experienced by individual needles during formation of needlepunched fabrics is demonstrated. The system design, coupled with a new signal analysis technique allows measurement of peak penetration and stripping forces as well as the penetration and stripping energies due to needle/fiberweb interaction. Systematic experimental investigations were conducted to determine the critical locations in the needle board where needles experience the highest forces, and correlate needle force parameters to fabric performance. The research results, supported by statistical analysis, show there is a strong relationship between needle penetration energy and fabric properties. Additionally, the needling density significantly impacts the location of maximum penetration forces.