Paper sack

Cement Sacks

A paper sack is a packaging made of paper high quality and weight, usually kraft virgin fiber, which is normally used for transporting powder materials, such as flour, cement, animal feed, etc. Multi-wall paper bags usually have several layers of heavy duty kraft paper, sometimes with a highly printed paper on the outside. Plastic films and coated papers are sometimes used as inner layers to provide a moisture barrier, and resistance to rodents and insects.

Usually consists of several layers to provide strength, with high elasticity and high tear resistance, designed for packaging products with high demands for strength and durability and resistant outer surface where instructions are printed, trademark, etc.^[1]

Paper sack manufacturing

Main articles: Kraft process and Paper machine

Wood pulp for sack paper is made from softwood by the kraft process. The long fibers provides the paper its strength and is added wet strength chemicals to even further improve the strength. Both white and brown grades are made. Sack paper is then produced on a paper machine from the wood pulp. The paper is microcrepped to give porosity and elasticity. Microcrepping is done by drying with loose draws allowing it to shrink. This is causing the paper to elongate 4% in machine direction and 10% in cross direction before busting.^[1] Machine direction elongation can be further improved by pressing between very elastic cylinders causing more microcrepping.^[1] The paper may be coated with polyethylene (PE) to ensure an effective barrier against moisture, grease and bacteria. A paper sack can be made of several layers of sack paper depending on the toughness needed.

Properties

Main article: Brown paper

Paper sacks are usually made of Kraft paper having the advantage of being soft and strong at the same time. The stretch or elongation increases the energy required to break the material. They easily carry and protect products up to 50 kg, and adapt easily to the nature of their contents and to handling constraints. At the same time sacks are provide an excellent media for promotional messages and sophisticated printing designs.

Paper sacks capacity is variable, each country sets a maximum ground rules such as job security, it comes in a variety of calipers, basis weights, and treatments.

Applications

Plastic hazard free paper sacks also called multiwall paper sacks are used for cement, food, chemicals, consumer goods, flour bags etc.

References

1 2 3 Paulapuro, Hannu (2000). "5". Paper and Board grades. Papermaking Science and Technology 18. Finland: Fapet Oy. pp. 121–122. ISBN 952-5216-18-7.

Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, ISBN 978-0-470-08704-6

External links

European federation of multiwall paper sack manufactures

Paper

History Manufacture/Papermaking

Types	Blotting Bond Construction Cotton Rag Crêpe Display Dó Asphalt Glassine India Korean Kraft Laid Manila Newsprint Oatmeal Onionskin Origami Baking Building Rice Rolling Security Seed Copy Tar Thermal Tissue Tracing Transfer Tree-free Wallpaper Washi Waterproof Wax Wood-free Wove Writing

Materials	Fiber crop Paper chemicals Papyrus Wood pulp Algal bloom (Shiro alga carta)

Specifications	Grammage Density Size Units of paper quantity Surface chemistry of paper Wet strength

Manufacture and process	Bleaching of wood pulp Calender Conical refiner Deinking Paper pollution Environmental impact of paper Hollander beater Kraft process Organosolv Paper cut Paper machine Paper recycling Soda pulping Sulfite process

Industry	Paper industry In Europe In Canada In India In Japan In the United States Paper mill List of paper mills

Category Commons

Packaging

General topics	Active packaging Child-resistant packaging Disposable food packaging Food packaging Luxury packaging Modified atmosphere/modified humidity packaging Package pilferage Package testing Packaging engineering Pharmaceutical packaging Reusable packaging Shelf life Sustainable packaging Tamper-evident Tamper resistance Wrap rage

Containers	Aerosol Container Aluminium bottle Aluminum can Ampoule Antistatic bag Bag-in-box Bags and flexible containers Barrel Beer bottle Biodegradable bag Blister pack Boil-in-Bag Bottle Box Bulk box Carboy Carton Chub Clamshell Corrugated box design Crate Disposable cup Drum Envelope Flexible intermediate bulk container Foam food container Folding carton Growler Insulated shipping container Intermediate bulk container Jar Jerrycan Jug Juicebox Keg Matryoshka doll Multi-pack Oyster pail Packet (container) Padded mailer Pail Paper bag Paper sack Plastic bag Plastic bottle Popcorn bag Retort pouch Sachet Security bag Self-heating can Self-heating food packaging Shaker-style pantry box Shipping container Skin pack Spray bottle Tin can Tube Unit load Vial Wooden box

Materials and components	Adhesive Aluminium foil Bioplastic Biodegradable plastic BoPET Bubble wrap Bung Cellophane Closure Coated paper Coating Corrugated fiberboard Corrugated plastic Cushioning Desiccant Double seam Foam peanut Glass Hot-melt adhesive Kraft paper Label Linear low-density polyethylene Liquid packaging board Low-density polyethylene Metallised film Modified atmosphere Molded pulp Nonwoven fabric Overwrap Oxygen scavenger Packaging gas Pallet Paper Paper pallet Paperboard Plastic film Plastic pallet Plastic wrap Polyester Polyethylene Polypropylene Pressure-sensitive tape Screw cap Screw cap (wine) Security printing Security seal Shock detector Shock and vibration data logger Shrink wrap Slip sheet Staple (fastener) Strapping Stretch wrap Susceptor Tear tape Temperature data logger Time temperature indicator Tinplate Velostat

Processes	Aseptic processing Authentication Automatic identification and data capture Blow fill seal Blow molding Calendering Canning Coating Containerization Curtain Coating Die cutting Electronic article surveillance Extrusion Extrusion coating Graphic design HACCP Hermetic seal Induction sealing Injection molding Laminating Laser cutting Molding Papermaking Plastic welding Plastics extrusion Printing Quality assurance Radio-frequency identification Roll slitting Shearing (manufacturing) Thermoforming Track and trace Vacuum forming Ultrasonic welding Vacuum packaging Verification and validation

Machinery	Barcode printer Barcode reader Bottling line Calender Can seamer Cartoning machine Case sealer Check weigher Conveyor system Extended core stretch wrapper Filler Heat gun Heat sealer Industrial robot Injection molding machine Label printer applicator Lineshaft roller conveyor Logistics automation Material handling equipment Mechanical brake stretch wrapper Multihead weigher Orbital stretch wrapping Palletizer Rotary wheel blow molding systems Shrink tunnel Staple gun Tape dispenser Turntable stretch wrapper Vertical form fill sealing machine

Environment, post-use	Biodegradation Environmental engineering Glass recycling Industrial ecology Life-cycle assessment Litter Paper recycling Plastic recycling Recycling Reusable packaging Reverse logistics Source reduction Sustainable packaging Waste management

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