A LAMINATED WOVEN BAG AND METHOD OF MANUFACTURING A LAMINATEDWOVEN BAG

Field of the Invention

The invention relates to a laminated woven polymer bag and method for making a laminated woven bag. More particularly a laminated woven bag for packaging & storing of bulk product including powder and granular form of food products , pet / animal foods or packaging of fertilizers, cement & chemicals etc.

Background of the invention :-

The ^N bags available as on today for packaging of bulk products are made of multi layer film or woven for packaging of food products like seeds, fertilizers etc. These kinds of bags do have processing troubles & have disadvantages of handling, carrying, storing and do not have sufficient strength. These bags don't have good barrier resistance properties. Good quality of printing is not possible because of non uniform lamination throughout the surface of woven.

In case of multi layer film bags, the bag does not have sufficient strength to withstand the product load because they are sealed which can give away easily. These kinds of bags do have easy tearing and are slippery on the surface, hence not suitable for large / bulk pack like 10 to 15 kg. or more. In case of existing laminated woven bag, the woven fabric is made from thin strip of Polyethylene or Polypropylene or any other suitable polymer or blend, in predefined size are woven together in tube form. A pre printed film of polymer is laminated on the outside surface of the woven tube to represent the product printing graphics and product details.

US 2007/0082158 relates to a multi-layered composite bag used to store bulk type products like pet food, seeds, fertilizer, cereals, grains and other bulk products intended for human and non-human consumption. This bag comprises a middle

layer of woven mesh tubing to which an outer layer of solid plastic film is adhered using polypropylene or some other poly laminate.

The first draw back of these bags is the poor quality of the film lamination on the woven, as the woven is in a tubular form. There is either a naked area (un- laminated) left at both the sides of the folding edge of the tube as the film lamination will always leave some gap at the folded side edge of the tube since the film lamination can not reach the folding area of the tube or the lamination is done extending on both the sides, sealed together & trimmed, leaving a hanging band of laminate film on both the sides. The other limitation of this type of bag is that the tube needs to be woven in various sizes depending upon the bag sizes required, whereas circular loom processing is not commercially viable for small quantity requirements in different sizes of bags requiring different sizes of tube.

Object and summary of the invention:

To obviate the aforesaid drawbacks, the object of the instant invention provides a laminated woven bag for packaging of bulk food products and a method for making a laminated woven bag.

It is yet another objective of the present invention to provide a method for making a laminated woven bag from the continuous running web rather than from a woven tube to improve the quality of lamination on the entire surface of the web & intern bags.

It is still another object of the present invention is to provide a re-closable and reusable laminated woven bag.

Yet another objective of the present invention is to provide easy carrying, tamper proof evidence laminated woven bag.

To achieve the aforementioned objectives, the present invention provides a laminated woven bag comprising :

• a printed laminated woven web folded at two ends overlapping & sealed to form a front and a back wall of the bag, in the form of a tube,

• a joining means for joining overlap of the woven web ends applied to form desired sizes and shapes of tubes, • two side gussets formed by folding and creasing both sides of said tube,

• a top closing means attached to the front and back walls of said bag for re- closing top opening of the bag or reusing the said bag,

• a bottom closing means for closing the bottom of the bag permanently after filling the product inside the bag. • bottom of the bag permanently after filling the product inside the bag.

The present invention also includes a method for making a laminated woven bag comprising the steps of:

^■ laminating a printed film on woven fabric surface by extrusion lamination process, ■ folding the laminated web at two ends, across the width to overlap & form a front and a back-wall of the tube,

^■ joining overlapped web ends by a joining means to form desired sizes and shapes of the tube,

^■ folding and creasing both sides of the said tube, forming two side gussets, ■ attaching a top closing means to the front and back wall of said bag for re- closing top opening of the bag or reusing the said bag, and

^■ attaching a bottom sealing means at the bottom of the bag for closing the bottom of the bag permanently, after filling the product inside the bag.

Brief Description of the accompanying drawings

The features of this invention are set forth with particularly in the appended claims. The invention, together with its objects and advantages thereof may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify substantially like elements in the several figures and in which:

Figure 1 shows the front view of a laminated woven sealed tube with side gussets according to the present invention

Figure 2 shows the front view of a complete bag with Zipper and diaphragm.

Figure 3 shows the front view of a complete bag with Zipper and without diaphragm seal.

Figure 4 describes the overlap seal of front and bottom wall.

Figure 5 shows the formation of side gusset from Front and back wall.

Figure 6 shows the Zipper and diaphragm attachment with front and back wall.

Figure 7 shows attachment of zipper without diaphragm with front and back walls of the bag.

Figure 8 shows the Bottom end of the bag for product feeding.

Figure 9 shows the cross sectional view of the zipper, slider, and diaphragm fixed with front and back wall. '

Figures 10A, 10B shows the attachment of a tape with the woven bag and Figure 10C shows a side view of a woven bag with sealed tape.

Detail description of the drawings :-

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated bag, and such further applications of the principles of the invention as illustrated therein being

contemplated as would normally occur to one skilled in the art to which the invention relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.

The laminated woven bag can be re-closable and re-open able. The bag provides a temper proof evidence property by diaphragm or filler tape or a sealed tape. A handle is attached to the bag for easy carrying of the bag. These bags are well suitable and safe for packaging of bulk food products, fertilizers & chemicals, other food products and consumables for human, pet, animals and other non human use.

The laminated woven is prepared from flat woven fabric in the form of roll and not from a woven tube. In this case 100% area is laminated from one end to the other end, across the width of the web. This improves the quality of lamination on the entire surface of the web.

Printed film of suitable polymer is laminated on woven fabric surface with the help of extrusion lamination process, ultrasonic lamination or by any other suitable technique. The width of laminated woven web can be fixed depending upon the size of the bag to be made. The printed laminated woven web, in roll form is then taken to the bag making machine where the web roll is folded to provide overlap of the two ends, sealed by adhesive, extrusion lamination, ultrasonic sealing or any other suitable technique, to form a tubular shape.

After making the tube on first station of the machine, the sides of the tube are folded and creased to make two side gussets of pre defined size and to represent two separate walls called as front wall and back wall.

This two side folded front and back walls then proceed to zipper slider fixing station. The male and female parts of the zipper with or without diaphragm is

stitched or fixed by using suitable adhesive or ultrasonically or any other suitable technique, with front and back wall at the top end of the bag. The zipper with diaphragm acts as temper proof evidence. The diaphragm is made of single or multi layer polymer film, non metalized or metalized with pr without holography, with perforation or Laser scoring, for easy opening. The zipper and slider assembly facilitates re-opening and re-closing of the bag which enables the safe storage of the products.

In another temper proof evidence, the bag is attached with or without an over lap filler tape, stitched with either front wall or back wall surface, below the zipper assembly to close the inner gap of the front & back wall. The stitch can be opened from one end by pulling the filler tape upwards which opens the stitched joint of front wall and back wall to open the bag mouth for pouring out the products from the bag. Other end of the front wall and back wall is kept unclosed for filling and packing of the product inside the bag and thereafter closed by means of locked stitch or by sealing the inner surface of the front and back walls by heat sealing or ultrasonic sealing or any other suitable technique, at predetermined, area permanently. Heat Sealing of inner surface of front & back walls may be done directly or after stitching a strip / ring of suitable polymer with the inside of front & back wall of the bag, all around, to give strong seal.

Figure-1 shows the front view of a side fold gusseted woven bag according to the present invention. The overlap (2) sealing is done by adhesion (A) or Stitching or Extrusion lamination or Ultrasonic sealing or any other suitable technique, by folding the two ends of the laminated woven web (1) across the width. The front wall (1a) and back wall (1b) are folded and creased towards center as shown (4) in this figure. The folds on both sides of front and back walls form two side gussets (3a) and (3b). The top of the bag is sealed by a top sealer (T) and bottom of the bag is sealed by a bottom sealer (B).

Figure- 2 shows a bag with one laminated woven front wall (1a) and one back wall (1b). The laminated web is folded across the width overlapping the two ends &

sealed at overlap (2) by adhesion or Stitching or Extrusion lamination or Ultrasonic sealing or any other suitable technique, of the laminated web. After two ends are sealed, the web surfaces on top & bottom represent two separate walls of the bag called as front wall (1a) and back wall (1b). The bag comprises of two side gussets (3a) and (3b) folded towards inside at center (4).

For re-closing and re-opening the bag mouth, a zipper assembly (5a) and (5b) with diaphragm (6) or without diaphragm, is stitched or fixed by adhesive or ultrasonic sealing with the inside of front and back wall, across the width. The stitches can be either in single row or two rows (8a) and (8b). One part of the zipper is called as male part & other as female part. The diaphragm is pre sealed with the zipper assembly before fixing on to the front and back wall. Male part is joined with front wall & female part is joined with back wall or vice-versa, across the width. A slider device (12) is used for the purpose of opening and closing the zipper assembly for re-closing and re-opening of the bag. The slider movement on the zipper is blocked at both the ends of the zipper by sealing the male and female parts of the zipper together at both the ends, as shown (11a) and (11b).

This male and female zipper end sealing after fixing of slider on the zipper assembly, can be prepared separately as subassembly for each bag as per required size. The male and female parts of zipper can be stitched or joined with ultra sonic sealing with the front and back walls of the bag, all around.

The male & female parts of the zipper without slider & end sealing, can also be stitched or joined with ultra sonic sealing with the front and back walls of the bag, all around & slider assembly & end sealing is done subsequently.

A pair of handles (13), depending upon the bag weight with product and if required for easy carrying and handling are fixed on the front and back wall surface, as required.

Another temper proof provision, as explained is the filler tape (9), stitched on the outer surface of front or back wall by a single stitches (10), The stitches with filler

tape are removable to open the mouth of the bag by pulling one end of the tape upwards.

The other end of the bag is kept open for filling the product inside the bag and there after closing the bag by a sealing means (S1) or by a stitching means (S2).

Said sealing means and stitching means closed the bottom of the bag by locked stitch or by sealing the inner surface of the front and back walls by heat sealing or ultrasonic sealing or any other suitable technique, at predetermined, area permanently. Heat Sealing of inner surface of front & back walls may be done directly or after stitching a strip / ring of suitable polymer with the inside of front & back wall of the bag, all around, to give strong seal.

Figure-3 shows the zipper assembly without diaphragm. A filler tape (9) is stitched on the surface of the front or back walls of the bag to seal the bag mouth & bear the load of the product inside the bag during handling. It also acts as temper proof evidence.

Figure 4 shows the over lap joint (2) of two ends of the laminated woven web. The laminated woven web roll is slit to the required width as per the size of the bag. Both the ends of the laminated woven web are folded, overlapping each other in such a way that it produces two walls called as front wall and back wall of the bag. The overlap joint is made by adhesion or Stitching or Extrusion lamination or Ultrasonic sealing or any other suitable sealing technique, using suitable machine and applicator to achieve proper strength and quality.

In figure -5 the front and back wall is folded towards center from the end of two walls edges (14a) and (14b), it is creased and folded to make the side gussets (3a, 3b).

Figure-6 shows the zipper and diaphragm assembly fixed with front and bottom walls of the bag. The diaphragm is sealed with the Zipper along the length (7), prior to fixing with the bag walls. The diaphragm acts as temper proof evidence. A

slider (12) is assembled over the male and female zipper parts for closing and opening the zipper (15). The end of the male and female zipper parts along with diaphragm are sealed together to restrict the opening of the zipper at the ends, and not to allow the slider to come out from the zipper beyond the ends (11a & 11b).

Figure-7 shows attachment of zipper without diaphragm with front and back walls of the bag. The male and female zipper parts are fixed by adhesion or Stitching or Ultrasonic sealing or any other suitable technique, with the front and back walls of the bag, across the width of the bag's one end.

A separate narrow polymer strip or laminate or fabric (9) is stitched on the outside surface of the front wall or back wall, at predetermined position from the end of the bag mouth. It protects the inside product not to fall down or come out beyond this closer during storage or handling. It also acts as temper proof evidence.

Figures 8a, 8b and 8c show the bottom end of the bag kept open (16) for filling the product into the bag. After filling the product in the bag, the front and back walls are sealed by Adhesion or Stitching or Ultrasonic sealing or Heat sealing or any other suitable technique, to close the bag permanently.

Sealing of inner surface of front & back walls may be done by a stitching means (2, 23). The stitching means is stitched directly or after stitching a strip / ring of suitable polymer with the inside of front & back wall of the bag, all around, to give strong seal, at a predetermined distance from the bottom end of the bag. The front and back walls are sealed by a sealing means (21). When the sealing process is used on this area then the inner narrow film gets sealed to each other and closes the bag permanently at this bottom end.

Figure-9 is a cross sectional view which explains the fixing pattern of the zipper male and female parts (5a) and (5b), diaphragm (6), slider (12) with front and back walls (1a) and (1b). The stitching / sealing point of zipper with front and back walls is shown as (8a) and (8b). The filler tape is stitched with the front and back walls as shown at point (9) in the cross sectional view.

Figures-10A, 10B show the attachment of a tape with the woven bag and Figure 1OC shows a side view of a woven bag with sealed tape. One end (17) of the laminated tube is to be used for taking out the product from the bag. This is closed by polymer film / laminate tape using suitable adhesive & application method. The end of the laminated tube is folded to a suitable width, twice or more times to get a narrow leak proof closing. Depending upon the product volume inside the bag and requirement of re-closing/re-opening of the bag a closing means zipper and slider assembly to be attached at this end. The zipper fixed at this end is accommodated within the folded gap, the slider remain at the end of the zipper, free from the folded area. A tape of predefined width is used for closing the folds. One end of the width of the tape is pasted / glued on the surface of the folded end (19) of the tube and the other end of the width of the tape is pasted / glued on the surface of the wall of the tube (20), as shown in fig 10B & 10C. The center area (18) of the tape along the length is unsealed and comes in between the folded end and the tube surface thus remains open in that area.

The side view of the folded laminated tube and the sealing area is as shown in the figure 10C. The advantage of this kind of seal is that it is easy to open. The unsealed area of the tape is pulled upwards easily from either end which will separate the folded end of the bag from the bag wall surface. Once the folded end seal is detached from the bag wall surface, the bag mouth can be opened by unfolding the folds. This type of bag seal avoid the stitching and stitch removing trouble in the bags available in the prior art. The opening is clean without any residual threads and also the opening ends can be easily located by visually impaired person.

All documents cited in the description are incorporated herein by reference. The present invention is not to be limited in scope by the specific embodiments and examples, which are intended as illustrations of a number of aspects of the invention and embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments

of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims.