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BIG BAG
Big bag is a flexible bulk packaging container which is used in many different areas
like agriculture, building, chemistry, mining, storing, transportation and other industrial sectors.
Fibc, flexible intermediate bulk container, is the other technical name of big bag. Jumbo bag, large bag, bulk bag and super sack are also used to name this
useful and environment friendly packaging material. Packing 1000kg, 1500kg and 2000kg product in big bag is more practical
and less costly compared to packing in 25-50 kg sacks.
Polypropylene resin mixed with colorants and UV inhibitors is melted
between 200 to 275 C degrees in extruders and becomes continuous film in certain
deniers (between 800 and 2000 deniers) with high tenacity and resistance. The film is cut into tapes in certain
width and directed through chill rolls to be cooled and balanced for the
tenacity, thickness and elasticity and then winded on small rollers to be put on
weaving lines.
On
weaving lines, hundreds of tapes are directed to one loom to support the weaving
process, and loom uses these tapes as weft and warp to construct the body of
polypropylene fabric.
On
circular loom the fabric is circular woven and on plain loom the fabric is
flat woven. For the production of potato and onion big bag, ventilated fabric
is woven with several air bands (13 or 26 ventilation bands) by the looms.
Conductive fabric needs another technical process to put antistatic bands inside
the weaving to prevent static electricity around the big bag.
Polypropylene fabric may be coated on lamination machine and this will prevent
the leakage and air circulation between the tapes and dustproof filler cord must
be used on stitches for the big bag which is used for packing powder and fine products.
Fibrillated tapes are used to support narrow weaving looms to produce webbing
which was used to make the loops for the flexible containers.
On
the other hand, the fibrillated tapes are twisted in 3500 to 4500 denier and
lubricated to produce the sewing yarn that is used to sew the jumbo bag.
FIBC (flexible intermediate bulk container) is formed mainly from
polypropylene materials; fabric, webbing and sewing yarn. These materials have to
be in high strength and tenacity and comply with the SWL (safe working load)
and SF (safety factor) of the bag. So these materials are evaluated in
technical textile group, tested and certified by certain laboratories.
Woven fabric, webbing and sewing yarn are inspected and controlled for quality
before dispatched to the big bag production. The rolls of fabric are put on heat
cutting machines and cut in programmed length, and webbing also cut by heat
cutting and marking machine into requested length. marking machine into requested length.
Then they are put in the sewing section to be composed as a big bag in the
specifications of customer. Composition of the materials are mainly done by
over-lock and safety stitches after the preparation process for spouts and loops.
Document pocket and safety labels are put on the big bag during the sewing
process.
After the sewing process, big bags are taken into cleaning and final control
sections to make the final checks and prepare them for the palletizing section.
Palletized big bags are covered with stretch films and pp coated light fabric
before they are dispatched to the loading section.
SWL (safe working load) means how many kg or ton product you can carry in the
big bag safely, and SF (safety factor) means the number of triples that the
big bag can be used. SWL for big bag starts from 250 kg up to 2000 kg, and SF
mainly 5.1 and 6.1 are used. Safety factor 5.1 is used for single trip usage
and 6.1 is used for multi trip big bags.
If
we want to give some brief information about the classification and kinds
of big-bag; A-B-C-D types are the technical classification of the
product (Antistatic, Conductive, standard, etc.). Q-bag, 4 loop standard big
bag, cross corner bag, one loop big bag, asbest container bag, sling bag,
ventilated potato bag are available as sorts of FIBC types.
Big bags are generally used in the following areas; mining (sulphur, lime, coal), agricultural products and foodstuffs (legumes, cereals,
flour, semolina, nuts, dried fruits and vegetables,
potato, onion), cement, chemical products
(magnesium, silicon,
and petrochemicals), oil by-products, wastes (asbestos, plastic-waste, chemical waste), construction materials (sand, cement, lime, rubble waste, pumice, gypsum), soil products (ceramics, tiles, bricks, special soils, clay) and in many
other industrial production and storage classes.
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