Spunlace Product Line
Spunlacing 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 hydroentangling process.
While some of them are typical in a nonwoven process, some of them are unique to the process of spunlacing. The steps characteristic for producing hydroentangled nonwoven fabric include:
Precursor web formation
The formed web (usually air-laid or wet-laid, but sometimes spun bond or melt-blown, etc.) is first compacted and prewetted to eliminate air pockets and then water-needled. The water pressure generally increases from the first to the last injectors. Pressures as high as 2200 psi 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 m m 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 hydroentangled product is then passed through a dewatering device where excess water is removed and the fabric is dried.
Hydroentanglement carried out at standard conditions (six manifolds of needles, 1500 psi, 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 . Spunlaced fabrics have led to a lot of speculation regarding their manufacture because mos