1. Geotextile Raw Materials:
At present, the main raw material of geotextile is synthetic fiber.The selection of various synthetic fibers should be combined with the actual situation of the project, considering not only the physical and chemical performance requirements of the field used, but also the product cost among them, polyester fiber and polypropylene fiber are the most widely used, followed by polyamide fiber and polyvinyl acetal fiber.
1.1 Polyester fiber advantage and disadvantages:
Advantages:Polyester fiber has good physical and mechanical properties, excellent toughness and creep properties, high melting point, high temperature and aging resistance, mature production process and high market share.
The disadvantages are poor hydrophobicity, easy to accumulate condensed water when used in thermal insulation materials, poor performance at low temperature, easy to glass, low strength, poor resistance to acid and alkali.
non woven polyester geotextile is widely used in civil engineerings.
1.2 Polypropylene fiber advantage and disadvantages:
Advantages: Polypropylene fiber has better elasticity and instant elastic recovery than polyester fiber; it has good acid and alkali resistance, wear resistance, mildew resistance and low temperature resistance; it has good hydrophobicity and core absorption performance, which can make water transfer to the outer surface along the fiber axis; it has a small density, only 66% of polyester fiber, and non woven polypropylene geotextile fabric can obtain fine denier fiber with tight structure and superior performance through multiple drafting, which can be reinforced with coordination The process can make its strength more superior.
The disadvantage is that it is not resistant to high temperature, the softening point is 130-160 ℃, the light resistance is poor, and it is easy to age and decompose in sunlight, but it can be made to have the UV resistance by adding auxiliary agents such as UV absorber.
1.3 Natural fiber and special fiber to make non woven geotextile clothes:
In addition to the above fibers, jute fiber, polyethylene fiber, polylactic acid (PLA) fiber can also be used as raw materials of nonwoven geotextile.
Natural fiber and special fiber have gradually entered into various application fields of geotextile, such as natural fiber (jute, coconut shell fiber, bamboo fiber, etc.) in subgrade, drainage, revetment, soil erosion control and other fields.
With the continuous development of new materials, the selection range of nonwoven geotextile materials continues to expand, coupled with the progress of production technology, more and more functional geotextiles show the market, showing the vigorous development of geotextiles.
2. Production process of nonwoven geotextile:
Compared with woven geotextile, nonwoven geotextile membrane fabric production process is less.
In recent years, nonwoven geotextile has developed rapidly because of its high production efficiency, low production cost and wide product. According to the different methods of forming net, the common production processes of non-woven geotextile include filament spunbond needle punched technology and staple fiber needling technology.
2.1 Filament spunbond needle punched technology:
The technology of spinning, sticking and needling is to melt the polymer and spin it into continuous filament fiber when the long tow is not fully solidified, it is a one-step nonwovens technology which is reinforced by needling. This technology has the advantages of short technological process, high output and tensile strength of geotextile under the same specification.
The properties of strength, tear strength, elongation at break and aspect ratio are much better than those of short fiber needled geotextile, which are suitable for engineering applications such as reinforcement and reinforcement. However, the investment of spunbond needling equipment is large, the evenness of forming net and the flexibility of product transformation are poor, which are not suitable for small batch and multi variety production.
2.2 Staple fiber needling technology :
Staple fiber needling technology is a two-step Nonwovens Technology, which is made of polymer heating, melting, spinning, drafting, curling, shaping, cutting and packing, and staple fiber opening, carding, netting, needling and consolidation into cloth.
The product is characterized by large thickness, high density, fluffy structure, good water absorption and permeability, and strong deformation resistance, especially suitable for anti filter material.
Needle punched nonwovens have the advantages of short process flow, many kinds of raw materials, simple equipment structure and less one-time investment. Therefore, the geotextile processed by needle punched short fiber is the most widely used in non woven needle punched geotextile production in China.