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Types of Paper Bags
 
Sewn Open Mouth (SOM)
This bag is made from a flush cut tube, which is closed at one end by sewing and left open at the other end for the customer to pack. The customer will then close this end by sewing, stapling or wire tying. Its characteristics are:
  • Can be made fairly sift resistant
  • Can use a variety of barrier plies
  • It is available in a wide range of sizes
  • Customer must provide closing materials
  • Needle holes preclude good moisture protection
  • Pointed ends stick out when palletized
  • Simplest
  • Least expensive
This style bag is used primarly for seed, feed and fertilizer. It represents a market where plastic bags have penetrated very successfully.
 
Self Open Sack (SOS)
This style bag is gusseted with a square pasted bottom closure. The other end is left open for packing. The customer will close this end by sewing, stapling or taping. Its characteristics are:
  • The square end provides a good shape for palletizing and allows the bag to stand up unsupported for filling.
  • In small consumer size, the bottom provides an area for print identification when the bag is lying on the shelf.
  • Recent developments now allow laminated film plies to be used.
  • Customer must provide his own closing materials.
  • This style bag is used as a consumer package for 10 pounds or less of product, as a baler bag to hold several smaller packages, and for batt insulation. A few customers use this style bag for feed supplements and chemicals.
All wet strength kraft refuse sacks are finding wide acceptance as opposed to the all plastic refuse sack that does not degrade well in land fill disposal. Ecology minded cities and corporations are finding that this square bottom, 3 cubic foot (16x12x35"), all wet strength kraft bag fits well into their plans for a more responsible America.
 
Pasted Open Mouth (POM) Satchel Bottom
This style bag is a flat tub with a pasted bottom closure. The other end is left open for packing. The customer will close this end by sewing, stapling, taping or wire tying. Its characteristics are:
  • This style bag is similar when filled to a SOS style bag.
  • The flat tube top, when closed, has a tendency to be pillow shaped thus detracting from the appearance of the package/stacking pattern.
This style is not called for very often. The most popular use of this bag is a baler bag for sugar or rice, two to ten-pound packages.
 
Double Roll Fold Mitered Corner (DRFM)
This style bag is gusseted with a heat sealed and pasted roll over bottom. The essential characteristic is the mitered corners that from a square bottom when the package is filled. Primary markets for this small bag are:
  • Insecticides
  • Herbicides
  • Lawn care products
  • Food products
This bag has exceptional non-sifting properties.
 
Pinch Bottom Open Mouth (PBOM)
This style bag is gusseted with a fold over pasted closure on the bottom and a pre-applied thermoplastic adhesive at the top for the customer to reactivate in closing. Its characteristics are:
  • This style bag provides a very sift proof closure, and can employ a variety of barrier plies.
  • This bag can be packed and closed on automated equipment, which can be operated and maintained by unskilled labor.
  • This bag can have an airtight seal on both ends.
  • This style offers a print area on the ends of the bag for product identification while the bags are lying flat.
  • The ends of this style bag will remain pointed when the bag is filled.
  • This style is limited in practical thickness (gusset size) to a maximum of 6 1/2".
Pinch bottom bags are generally used to package more expensive or sensitive products than Sewn Open Mouth is. Recently, pinch bags have begun to replace sewn bags in pet food, fertilizer and flour.
 
Webb Bottom Pinch Top (SSWBPT)

This style bag is gusseted with a square pasted bottom (like SOS) and pre-applied thermoplastic adhesive at the top (like PBOM). As the description implies, this style bag incorporates the good palletizing shape of the SOS style and the easy closing feature of the pinch bag. Though this style bag is more expensive than pinch it competes by offering more bags per truckable pallet with pallet shapes that can stack three high in a warehouse. This will reduce breakage in the warehouse and during truck loading. In evaluating the webb bag, it is important to remember that the cost of packaging includes more than the cost of the container.

This special style bag often provides a means of making an effective pallet load pattern and a means of developing an effective truck-loading pattern when other bag styles would not do.
 
Pasted Valve Stepped End (PVSE)

This style bag is a flat tube width a pasted top and bottom. One corner is left open and a sleeve is placed in that corner for filling. this is the most common multi-wall bag style today. It accounts for more than 70% of the multi-wall bag market. Its characteristics are:
  • This style can employ a variety of barrier plies.
  • Filled bag has a good palletizing shape.
  • This style is not completely sift proof.
  • The maximum thickness (bottom size) is 9 inches.
  • This style bag is used for virtually every type product. However, federal rules and National Freight ruling bodies are reviewing its use for hazardous and nuisance products.
  • This style bag allows the use of valve packers (air,augers,impeller and belt) in the packaging of dusty and very difficult products.
  • The valve bag provides a means of packaging without the expense of an additional closing operation.
Craighead Valve (CV)

This bag is gusseted tube with square SOS pasted ends. One corner is left open and a sleeve is used for filling. This sleeve offers a thickness up to 9 inches. This bag is flush cut. Characteristics of this sytle are:
  • This style bag is the same size empty as it is filled.
  • This style is ideal for packing fluffy products. An example would be the carbon black industry using this style to pack fluffy blacks.
  • This CV style retangular bag works well on the vacuum packers where special light products are packed; insuring a firmer, more evenly packed pallet load.
  • Only Bancroft offers this special package.
 
Webb Valve Pinch Bottom (WVPB)

This style bag is a gusseted tube with a pinch closed bottom and a square top with one coner open and a sleeve for filling. This special style bag competes with sewn valve and pinch valve bags where pasted valve stepped in bags do not, since they don't provide the moisture protection certain products require.

Where this package has been used, it has effectively accomplished the job of improving palletized load shapes. This bag is much easier to spout than the pinch style valve bag offered by others.

This special package is exclusive to Bancroft Bag, Inc.
 
Webb Valve Squares (WVS)

This style bag appears identical to the Craighead Valve Bag, but it uses a stepped end tube thus allowing the use of sophisticated barrier plies in the bag.

When this bag is used, it provides a very neat package and pallet-stacking pattern. The Webb Valve Square bag provides a means of fitting a very light product onto a pallet thus allowing truck transit, which may not have been an option otherwise.

This style is exclusive to Bancroft Bag, Inc.

 
Webb Bottom Flush Cut Top (SSWBFC)

This style bag is exactly like the Webb Pinch Top bag except that the top is cut off flush. Customers who were using SOS bags but felt it necessary to graduate to more sophisticated barrier plies than the SOS style can provide use this style.

This style can also provide protection from adhesive contamination and contact with paper fibers.