Raw materials for the production of nonwovens
Cellulosic chemical fibers of all lengths and degrees of refinement and with clearly different properties are at the disposal of the industry of nonwoven bonded fabrics. They are all characterized by the ability to absorb a fairly high amount of moisture. That recommends their use wherever this property is useful for the production of nonwoven bonded fabrics and/or the use of nonwoven bonded fabrics is even a precondition.
Nonwovens are textile fabrics consisting of separated fibers which are arranged properly by means of end-user-oriented technologies. In order to guarantee serviceability of the finished product, they are bonded. For this reason, the choice of fibers and possibly bonding materials is of special importance: This relates to fiber raw materials and fiber dimensions. As a rule, they have a greater share in creating the specialties of the nonwovens than this is the case in textile fabrics made of yarns. The bonding agents can also have an impact on the quality of the non-wovens.
Fibrous materials used for Non-wovens
Virtually all kinds of fibers can be used to produce nonwoven bonded fabrics. The choice of the fibre depends on:
- the required profile of the fabric and
- the cost-effectiveness to produce nonwoven bonded fabrics
- chemical fibers of both cellulosic and synthetic origin as well as
- natural fibers and
- inorganic fibers are mainly used
Because such a wide range of fabrics is either being developed or is already in production, it is impossible to name and describe all fabrics and fibers. The most important details will be provided below and the relevant literature will be cited.
The most important constituent of vegetable fibers is cellulose, which is hydrophilic and hygroscopic. Apart from cellulose, vegetable fibers also consist of several other substances which affect their properties. Cotton is the most important vegetable fiber used to produce nonwoven bonded fabrics.
Animal fibers Sheep’s wool (Ovis aries)
Of all the animal wool and hair, only sheep’s wool is of any importance for the production of nonwoven bonded fabrics. As its price is high, it is used mainly in the form of reclaimed wool or cuttings. The variations in quality and the impurities in reclaimed wool as well as the chemical and physical properties determined by its provenance impose restrictions on its use.
Man-made fibers from synthetic polymers
The field of nonwoven bonded fabrics has become so broad that it includes nearly all kinds of existing fibers to some extent. However, specific fiber types have become predominant in certain areas within this field.
The two main types of fiber are polyamide 6, usually known as Perlon, and polyamide 6.6, which is generally called Nylon to distinguish it from Perlon. The number or numbers after the word ‘polyamide’ indicate how many carbon atoms there are in each molecule making up the polyamide.