INTRODUCTION

The teachings herein relate to apparatus and methods for manufacturing tote bags from nonwoven fabric. More specifically, apparatus for manufacturing tote bags from nonwoven polyethylene terephthalate (PET) fabric includes an ultrasonic bag welding device that ultrasonically welds seams and handles of tote bags using sonotrodes capable of reaching the melting point of nonwoven PET fabric. Promotional information is printed directly on nonwoven PET fabric tote bags using dye sublimation. In addition, a method for manufacturing tote bags includes laminating biaxially oriented polypropylene (BOPP) film to nonwoven polypropylene (PP) or PET fabric. Branding or promotional information is printed on the BOPP film.

Reusable Shopping Bags

Reusable shopping bags are becoming increasingly popular as a replacement for single-use or disposable plastic bags. Reusable shopping bags are now commonly used to transport groceries from a grocery store, for example. Reusable shopping bags often come in the form of a tote bag. A tote bag is typically an unfastened pouch with parallel handles. A tote bag can be made of almost any type of material but is usually made of fabric or plastic.

FIG. 1is an exemplary diagram100of a gusseted tote bag. The tote bag ofFIG. 1, includes front110, back120, gusseted sides130and140, handles150and160, and bottom170. Front110, back120, gusseted sides130and140, and bottom170can be formed from a single sheet of fabric, for example. The bag is created by sewing seams of gusseted sides130and140and sewing handles150and160to front110and back120, respectively. A gusset is, for example, extra fabric that makes a bag roomier and stronger. If bottom170is also gusseted, the tote bag ofFIG. 1can be referred to as an all side gusset tote bag. Other types of tote bags include, but are not limited to, flat tote bags and bottom gusset tote bags.

Promotional Tote Bags

Tote bags are now so widely used that they have become an ideal vehicle for branding or promotional information. For example, businesses use them to display advertising, their brand names, or logos. This promotional use of tote bags has placed at least three interrelated constraints on the manufacture of tote bags. First, there is a need to increase the bag production rate at a lower cost. Second, there is a need to increase the quality of the promotional information placed on the bags. Finally, there is a need to both increase their production rate at a lower cost and increase the quality of the promotional information placed on the bags while producing just a small number of bags, for smaller businesses or special events.

One method of addressing the first constraint has been to lower the cost of attaching the handles of the tote bag and sealing the seams of the tote bag. Traditionally, attaching the handles and sealing the seams has been performed by stitching or sewing the fabric. More recently, the speed of these tasks has been increased and the cost lowered by ultrasonically welding the handles and ultrasonically welding the seams of a tote bag.

It is possible to ultrasonically weld the handles and the seams of a tote bag made of a nonwoven fabric. INDA, Association of the Nonwoven fabrics industry, has defined nonwoven fabrics as: “ . . . as sheet or web structures bonded together by entangling fiber or filaments (and by perforating films) mechanically, thermally, or chemically. They are flat, porous sheets that are made directly from separate fibers or from molten plastic or plastic film. They are not made by weaving or knitting and do not require converting the fibers to yarn.”

Specifically, ultrasonic tote bag making machines have been developed to automatically make tote bags at a rate of about one bag per second using nonwoven polypropylene (PP) fabric. These machines cut, fold, and weld the fabric, performing the previous functions of up to 50 textile workers, for example.

FIG. 2is an exemplary top view diagram200of an ultrasonic tote bag manufacturing machine that is used to manufacture tote bags from nonwoven PP fabric. Feeding device220feeds and cuts nonwoven PP fabric from nonwoven PP fabric roll210. Handle forming and sealing device230folds and then attaches two handles to each tote bag. Handle forming and sealing device230folds and attaches the handles to each tote bag using one or more ultrasonic devices235that weld each handle to each tote bag.

One or more ultrasonic devices235are sonotrodes, for example. Each sonotrode includes a piezoelectric transducer236and a tapered metal end or horn237. Piezoelectric transducer236, for example, produces vibrational energy that is applied to a fabric (not shown) through tapered metal end237that is placed on the fabric. Tapered metal end237is placed on the fabric using a certain clamping force or pressure. In order to achieve a specific weld temperature, a sonotrode is designed and then controlled to have a specific weld time, frequency, amplitude, and pressure.

Mainframe240stores and can fold each tote bag. Tote bags are stored or buffered, for example, to maintain a high manufacturing rate. Mainframe240also houses a control computer and motor. The control computer can be a controller, a microprocessor, the computer system ofFIG. 3, or any device capable of sending and receiving control signals and processing data.

Bag forming device250forms the sides, bottom, or sides and bottom of each tote bag creating the side, bottom, or side and bottom seams. Side gusset tote bags, flat tote bags, or bottom gusset tote bags can be manufactured, for example. Ultrasonic bag welding device260ultrasonically welds the seams of each tote bag using one or more ultrasonic devices265. Finally, collecting device270collects each finished tote bag.

Using the ultrasonic tote bag making machine ofFIG. 2and nonwoven PP fabric, tote bags can be made at a high production rate and low cost. Unfortunately, however, high-quality promotional information cannot be placed on tote bags made of nonwoven PP fabric. Text may be printed on this material but not high-quality and colorful images. In addition, it is difficult to print promotional information in small batches on this material. As a result, two of the three constraints described above for the promotional use of tote bags cannot be met with nonwoven PP fabric. In addition, there is currently promotional value in including recycled material in the manufacture of tote bags.

Consequently, there is a need for apparatus and methods that can manufacture tote bags with high-quality promotional information printed on them, that can manufacture these tote bags in small batches, and can include recycled material in the fabric used, while at the same time maintaining a high production rate and low cost.

SUMMARY

Apparatus and methods are disclosed for manufacturing tote bags from nonwoven polyethylene terephthalate (PET) fabric. The apparatus includes a bag forming device and an ultrasonic bag welding device.

The bag forming device forms at least one piece of nonwoven PET fabric into at least one tote bag. The ultrasonic bag welding device then ultrasonically welds at least one seam of the at least one tote bag. The ultrasonic bag welding device uses at least one sonotrode operated to produce a frequency greater than or equal to 20 kHz and a pressure greater than or equal to 2,500 N.

Apparatus and methods are also disclosed for manufacturing full-color graphic printed tote bags made from biaxially oriented polypropylene BOPP) film laminated to spunbond nonwoven polypropylene (PP) or PET fabric in one process. In these embodiments, at least one full-color graphic is printed on the BOPP film before it is laminated to the nonwoven PP or PET fabric. The apparatus includes a printer, a laminator, and an ultrasonic bag welding device.

The printer receives BOPP film from a roll of BOPP film and prints at least one full-color graphic on the BOPP film for each of a plurality of tote bags. The laminator receives the printed BOPP film and simultaneously receives nonwoven PP or PET fabric from a roll of nonwoven PP or PET fabric, and laminates the printed BOPP film to the nonwoven PP or PET fabric as the printed BOPP film. The ultrasonic bag welding device receives the printed BOPP film laminated to nonwoven PP or PET fabric finished version of each of the plurality of tote bags. The ultrasonic bag welding device produces the finished version by cutting the printed BOPP film laminated to nonwoven PP or PET fabric for each tote bag, cutting part of the printed BOPP film laminated to nonwoven PP or PET fabric for handles for each tote bag, ultrasonically welding the handles to each tote bag, forming each tote bag, and ultrasonically welding together seams for each tote bag.

Apparatus and methods are also disclosed for manufacturing full-color graphic printed tote bags made from BOPP film laminated to nonwoven PP or PET fabric in which at least one full-color graphic is printed on the BOPP film after it is laminated to the nonwoven PP or PET fabric. The apparatus includes a laminator, a printer, and an ultrasonic bag welding device.

The laminator receives printed BOPP film from a roll of BOPP film, receives nonwoven PP or PET fabric from a roll of nonwoven PP or PET fabric, and laminates the printed BOPP film to the nonwoven PP or PET fabric as the BOPP film is received from the roll of BOPP film. The printer receives the BOPP film and prints at least one full-color graphic on the BOPP film for each of a plurality of tote bags. The ultrasonic bag welding device receives the printed BOPP film laminated to nonwoven PP or PET fabric and produces a finished version of each of the plurality of tote bags. The ultrasonic bag welding device produces a finished version by cutting the printed BOPP film laminated to nonwoven PP or PET fabric for each tote bag, cutting part of the printed BOPP film laminated to nonwoven PP or PET fabric for handles for each tote bag, ultrasonically welding the handles to each tote bag, forming each tote bag, and ultrasonically welding together seams for each tote bag.

These and other features of the applicant's teachings are set forth herein.

