Suzhou Swan Lake Felt Co., Ltd
Spunbond Nonwoven fabrics are produced by depositing extruded, spun filaments onto a collecting belt in a uniform random manner followed by bonding the fibers. The fibers are separated during the web laying process by air jets or electrostatic charges. The collecting surface is usually perforated to prevent the air stream from deflecting and carrying the fibers in an uncontrolled manner. Bonding imparts strength and integrity to the web by applying heated rolls or hot needles to partially melt the polymer and fuse the fibers together. Since molecular orientation increases the melting point, fibers that are not highly drawn can be used as thermal binding fibers. Polyethylene or random ethylene-propylene copolymers are used as low melting bonding sites. Spunbond products are employed in carpet backing, geotextiles, and disposable medical/hygiene products. Since the fabric production is combined with fiber production, the process is generally more economical than when using staple fiber to make Nonwoven fabrics.
In general, high molecular weight and broad molecular weight distribution polymers such as PP, PET, Polyamide, etc. can be processed by spunbonding to produce uniform webs. Medium melt-viscosity polymers, commonly used for production of fibers by melt-spinning, are used.
Spunbond fabrics are characterized by tensile, tear, and burst strengths, elongation-to-break, weight, thickness, porosity and stability to heat and chemicals. These properties reflect fabric composition and structure. Comparison of generic stress-strain curves of thermally bonded and needle-punched fabrics shows that the shape of the load-strain curves is a function of the freedom of the filaments to move when the fabric is placed under stress.
Today spun bonded webs are used throughout the automobile and in many different applications. One of the major uses of spun bonded webs in automobile is as a backing for tufted automobile floor carpets. The spunbonded webs are also used for trim parts, trunk liners, interior door panel, and seat covers.
ii) Civil Engineering
The civil engineering market segment remains the largest single market spunbond webs, constituting over 25% of the total. Spunbonded civil engineering webs cover a multiple of related uses, such as, erosion control, revestment protection, railroad beds stabilization, canal and reservoir lining protection, highway and airfield black top cracking prevention, roofing, etc. The particular properties of spunbonded webs - which are responsible for this revolution - are chemical and physical stability, high strength/cost ratio, and their unique and highly controllable structure which can be engineered to provide desired properties.
iii) Sanitary and medical
The use of spunbond web as a coverstock for diapers and incontinence devices has grown dramatically in the past decade. This is mainly because of the unique structure of spunbond, which helps the skin of the user stay dry and comfortable . Additionally, spunbond webs are cost effective over other conventional nonwovens. Spunbond web, as coverstock, is also widely used in sanitary napkins and to a limited extent in tampons.
In medical applications many traditional materials have been replaced by high performance spunbonded webs. The particular properties of spunbonded webs, which are responsible for medical use, are: breathability; resistance to fluid penetration; lint free structure; sterilizability; and, impermeability to bacteria. Medical applications include: disposable operating room gowns, shoe covers and sterilizable packaging.
Spunbonded fabrics are widely used as packaging material where paper products and plastic films are not satisfactory. The examples include: metal-core wrap, medical sterile packaging, floppy disk liners, high performance envelopes and stationery products.