Click on a letter below to be provided with a list of terms and definitions.
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rubbing or wearing away of a sheet of packaging material through
contact with some other material. (also see scuffing, chafing).
Pertains to the amount of liquid taken up by
paper, or the rate of uptake or time required for a paper to take up a
given amount of liquid. Rate or time of absorbency is more commonly
A chemical that yields hydrogen ions in water. It has
a corrosive action on many materials. The concentration of hydrogen
ions is stated in terms of pH value. Acids are less than pH 7.0.
Paper which has been treated to resist the actions of acids or acid fumes.
The state of sticking together or bonding two or more materials.
Adhesive, hot melt
An adhesive that is solid at room
temperature, liquefied by heat, applied in molten state and forms a bond
by cooling and solidifying.
An adhesive used to unitize loads of
bags or cases on a pallet providing low peel strength with high shear
strength to prevent sliding.
Bonding agents used in the manufacture of
shipping sacks. Most common adhesives are the waterproof-types made
from starch or dextrines. Others are polyvinyl acetate resin emulsions,
latex and hot melt.
United States Agency for International Development
A chemical that yields hydroxyl ions in water. It
has a corrosive action on many materials. The concentration of hydroxyl
ions is stated in terms of pH value. Alkalis are higher than pH 7.0.
A paper used to wrap materials that
have an alkaline reaction, such as soaps or alkaline adhesives. Paper
which does not show appreciable discoloration when wet with one percent
sodium hydroxide (caustic soda) is considered alkali-resistant.
All Creped Multiwall Sack
A sack in which all walls or paper plies are made from creped paper.
Aluminum Foil Coatings
Aluminum foil coated with polyethylene or other materials.
Aluminum Foil Laminations
A combination of thin aluminum
foil with a paper backing used as a barrier. A typical foil lamination
is kraft backing with aluminum foil laminated to the kraft paper by
means of an adhesive or extruded polyethylene.
Angle of Slide
The height at which a weighted sample
placed on another sample of the same material will begin to move or
slide down an incline as expressed in degrees of an angle.
A sheet of paper chemically or mechanically altered to increase the coefficient of friction (COF).
The weight per unit of volume of the
sheet of paper calculated by dividing the basis weight (500 sheets 24" x
36") by the caliper (in mils) and multiplying that figure by the factor
An alternative name for a self-opening sack (SOS).
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term frequently used interchangeably with sacks, but more accurately
applied to smaller consumer size packages, generally less than 20 lbs
Any paper used in making consumer sized bags.
The choice of paper depends upon the goods to be packed and the
Assembled, unfilled sacks wrapped and/or tied at the manufacturing plant ready for shipping to customers.
A large sack, usually made of one to three walls, designed to carry or unitize a quantity of filled smaller bags.
Pasting together the walls of a sack with lines (or bars) of paste as contrasted with spot pasting.
The weight in pounds or grams of a given area
of paper. For shipping sack kraft, this is the weight in pounds of
3,000 square feet. Historically, this represents the weight of a 500
sheet ream cut 24 inches by 36 inches.
A method of coloring paper in which colorants are added to the pulp before it is formed into a sheet.
Entire sack and contents such as clay or
titanium dioxide can be thrown into a beater for repulping. The sack is
made of repulpable kraft or bleached kraft and water-soluble adhesives
and water-dispersible inks.
The process of treating pulp with chemical
agents whereby non-cellulose materials are removed or altered to make
the pulp a whiter color.
A surplus printed area extending into the tucks
and/or bottom of a sack to allow for design tolerance while the sack is
being formed in manufacturing.
The description of a plastic film whose various
components were premixed before extruding as opposed to coextrusion
where the resins are extruded as separate layers into a single film.
The tendency of plastic film or plastic coated
papers to adhere or cling due to static electricity or shear-cut edges.
It can also occur due to improper formulation of plastic or to improper
anti-static treatment levels.
(Used as a noun) The attachment between a substrate and an adhesive or coating.
The end of the sack that usually rests on the floor or holder when being filled.
Adhesive used to make the end closure of pasted open mouth and pasted valve sacks.
A paper patch pasted over the bottom of a pasted open mouth sack or both ends of a pasted valve sack to prevent sifting.
The design or lettering of the brand that is printed on the bottom of the bag or sack.
A machine which automatically forms and seals both ends of a valve sack or one end of a pasted open mouth sack.
The complete process of cutting and folding a
bottom in a tube for pasted end bags. On certain machines, it also
refers to forming the valve end of the pasted end sack.
Bound Over Tape
Plain, extensible or creped paper tape sewn into the closure of a sewn style multiwall sack.
The print design and lettering and its location on the bag or sack as required by the customer.
An adhesive used to bond film to the
kraft ends of a sack giving the film the ability to break away at the
sack ends without tearing paper fibers.
The reflectivity or whiteness of a sheet of paper measured under standard conditions. Not a measure of color.
Paper scrap or waste that can be recycled into the paper machine.
The weight of a unit volume of a substance expressed as pounds per cubic foot or kilograms per cubic meter or equivalent units.
An upright frame partition used to separate and hold in place materials shipped in a railcar or truck.
A group of 15, 25, 50, or 100 bags that have been compressed and tied ready for shipment to the customer.
The resistance of paper to rupture under
pressure. Usually determined on a Mullen tester and expressed in
pounds per square inch. Also referred to as Mullen, Mullen strength, or
That part of the sack that becomes the top and the bottom when the bag is expanded upon filling.
Printing on the ends of a pasted sack.
A small diameter roll of material remaining after completion of a manufacturing run. Also called a stub roll.
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Calcium Carbonate Paper
A coating of calcium carbonate pigment and binder on kraft paper to improve acid protection
A series of rolls, through which paper is passed, to polish the surface and/or increase the density of the paper.
Defects in paper caused by wrinkles in the
paper as it passes through the calendar rolls. Defects appear as slits
or creases along the sheet.
Calendered Kraft Paper
Kraft paper having a smoother surfaced than regular natural kraft paper that was produced by a calender unit.
The thickness of a material such as paper or film expressed in thousandths of an inch or mil.
A heavy paper or paperboard made from kraft pulp
or waste paper stock. Used for lining freight cars to protect the
contents from dirt and abrasion.
Sodium hydroxide (NaOH), a strong, alkaline chemical.
Chafing The abrasion or scuffing caused by materials rubbing against one another or against another surface.
A coating of clay and binder on paper to
improve printing quality and appearance. Generally used for consumer
The result of sealing the ends of tubes.
A term applied to paper and paperboard whose
surface has been treated with clay or a pigment and adhesive mixture or
other materials to improve the surface finish with respect to printing
quality, color, smoothness, opacity or other surface properties. The
term also is applied to lacquered and varnished papers.
A warped or bulged spot in paper caused by excessive shrinkage during drying.
Coefficient of Friction (COF)
The ratio of the frictional
force to gravity acting perpendicular to the two surfaces in contact.
The tangent of the angle of slide. Also see Static COF and Kinetic COF.
The process of simultaneously joining two or more plastic layers together while still melted to form a single multilayered film.
A pattern of polyvinyl acetate water emulsion
coating applied on the printing press or bag machine to provide heat
sealable closure on paper bags or roll stock.
A natural latex rubber adhesive applied as a
pattern or overall coating to paper or film webs that only seals to
itself under pressure without heat. Also called self-sealing coating.
The resistance of color in paper, or
printed inks, to change shades when exposed to light, heat chemicals or
other deleterious influences.
Natural or bleached kraft paper to which a dye or pigment has been added to produce the desired color.
The exposure of paper to controlled and
specified atmospheric conditions, so that moisture content of the paper
reaches equilibrium with the controlled atmospheric conditions.
A bag containing a smaller unit of
merchandise that serves as a shelf package at the retail level.
Examples include, flour, sugar, and small pet food bags.
All materials used in the
construction of a bag or sack. Common conversion materials are paper,
thread, tape, adhesives, inks, etc.
A company that converts packaging materials into finished products such as bags, sacks, envelopes, pouches, boxes, tape, etc.
A vat or tank in which paste is cooked.
A tube, usually of paperboard, but occasionally of plastic, around which a roll of paper, film or foil is wound.
Metal, wood, plastic or particle board plugs
which are driven into the ends of the cores of a finished roll to
prevent the core from crushing.
Exposing a plastic film or poly coated
paper to a high voltage electrical discharge to increase the polarity of
the surface and thus increase receptivity to inks, coatings or
adhesives. Treatment level is expressed in dynes. Treatment levels
required vary for each type of film. Under treatment results in poor
bonding, while over treatment can cause blocking or heat seal problems
A corrosive material is a liquid or solid that
causes visible destruction or irreversible alterations to human skin
tissue at the site of contact.
A transverse score line placed near the top of a sack to facilitate forming the closure.
A term describing the effect produced by
"crowding" a wet sheet on a roll by means of a doctor blade. In sack
manufacture, creped paper is used to add flexibility and anti-slip
properties.The degree of crepe is indicated by percentages and usually
ranges from 3% to 30%. For example, 20 percent crepe paper will stretch
20% in a direction at right angles to the creping before it breaks.
A tube of creped paper used to from an internal or tuck-in closure in valve sacks.
Tape used in the end closure of sewn multiwall sacks.
Direction The direction at right angles to the machine direction,
corresponding to the direction of the width of a sheet of paper wound in
a roll. Also expressed as "across the machine" and "across the grain”
Spot or bar pasting across the width of a paper bag. Also see bar pasting and spot pasting.
The volume of material that a sack will
hold. Cubic capacity cannot accurately be determined from measurements
of an empty sack, but must be determined by filling trials, taking into
account entrained air in the product.
Usually applied to labels. An undesirable condition
in a stack of paper sheets, labels or wrappers usually caused by uneven
rates of absorption or evaporation of moisture on the two sides, or
internal stresses in the paper. The axis of the curl is usually parallel
to the machine direction of the paper.
In sack or bag manufacturing, that part of the tubing operations when the individual sack or bag is cut from the tubular web.
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The separation of the components of a laminated material.
The property of absorbing enough moisture from the surrounding atmosphere to change the material to a liquid form.
The weigh per unit of volume, usually stated as pounds per cubic foot or grams per cubic centimeter.
A simple method of folding the top and bottom
of a pasted sack distinguished by the diamond shape at both ends of the
top or bottom folds before sealing.
Paper cut with a sharp tool or die into a shape other than square cornered.
A kraft sheet used in the printing and
engraving trade for wiping the surfaces of printing plates. The
significant properties are a high finish, smooth surface, strength and
freedom from fuzz or lint.
A thin metal or plastic strip or scraper in
contact with a roll along its entire length to keep it clean. Also used
for creping paper.
A sewing machine with two sewing heads on
opposite sides for effecting the closure of both ends of a multiwall
sack during one pass of the bag through the sewing machine.
A set or sets of rolls which draw or pull the paper or sacks through the machine, also called pull rolls.
To spread or distribute ink or coating on paper
by means of pulling a blade down through the liquid. The sample obtained
by this method is also called a drawdown.
A method of comparing sack performance by
dropping filled sacks from predetermined heights and positions until
sack failure occurs.
That section of the paper machine consisting of the dryers, calenders, and reels.
A series of steam-heated, rotating metal drums on a
paper machine against which the wet paper is held by endless felts for
the purpose of drying the paper.
Embossed paper with a pattern of ridges and valleys in the machine direction.
blocking, lining, strapping, inflatable sacks or similar bracing or
supports used to hold a load in position for the purpose of preventing
loss or damage in transit.
Any paper showing different colors, texture
or finish on one side compared to the other side. Such paper may be
made by combining two different stocks on a paper machine.
Sacks made with two walls of paper, film or
other flexible materials which may or may not be the same grade, type
basis weight, etc.
Corona treatment level expressed as dynes/cm
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pointed extensions which appear at the corners of sacks after they are
filled and closed. Primarily appears on flat tube sacks.
The printing along the edge of a flat tube. The printing is visible on the side of the sack when the sack is filled.
Heavy paper used to protect the ends of paper rolls during shipment
Papers with impressed patterns created by
special impression cylinders running against a back-up roll. Lines or
other designs are created by embossing.
The operation of finishing a sack by closing the ends of the sack
A craftsman who engraves plates for printing.
Extended Lip Valve
A type of diamond fold valve used in
pasted multiwall bags wherein a valve extension is cut in one or all
plies at the tuber and forms a flap or lip which extends into the bag
and increases the length of the paper in the valve.
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The front of a bag or the side opposite the side of the bag on which the longitudinal seam is located.
The length of the finished, empty sack or bag measured from top to bottom
The distance from one edge of one gusset or
side of a sack or bag to the opposite edge measured across the face of
the sack or bag.
The side of the paper web that has not been in contact with the forming wire on the paper machine. Sometimes called "Topside".
The unit cell of vegetable growth, many times longer than its diameter, which is the basis of paper pulp.
A condition of bond or seal strength in paper
or other fibrous laminates where separation of components causes rupture
or tearing of the fibers.
A cushioning medium introduced around the
thread in needle holes so that the needle holes are sealed and the sack
strengthened. The material is usually twisted soft yarn, cotton or
twisted paper that is sewn into the needle holes to prevent sifting and
to act as a cushion for the sewing stitches.
Fin Seal or Fin Seam
A seam formed by bringing the same
sides of a ply together and sealing as opposed to an overlap seam where
one side is brought together with the other side.
The surface property of a sheet of paper determined
by its texture and gloss. High finish means smooth, glossy, hard
surfaces. Low finish means the absence of a high-gloss surface. Finish
is measured by reflected light.
he various operations in the processing of
paper that are performed after the paper machine, including slitting,
rewinding, sheeting, trimming, counting and packaging.
Strips of colored paper inserted into the edge of a
roll of paper by the printing press operator whenever a splice or defect
occurs. This is to let the next operator know when a splice or defect
in present in the roll.
A bag having no gussets
Paper that is relatively smooth, as opposed to a sheet that has been creped. (See Creped Paper)
Flat Sewn Open Mouth
A flat tube, without gussets, with one end sewn closed by the sack manufacturer.
Flat Sewn Valve
A flat tube, without gussets, closed top
and bottom by sewing that has a small opening or valve formed in one
corner for filling.
A tube that has no gussets.
A type of printing done while the
paper is still in the web and before the paper is formed into bags or
sacks. Flexographic printing is generally water based inks, although
some solvent based inks are used.
Flush Cut Top
All sack walls are cut off evenly across the top; not stepped-end.
Fold Over Tape
The tape sewn into the closure of a multiwall sack.
The distribution or arrangement of fibers in a
sheet of paper. Usually judged by visual appearance via transmitted
light. A "closed" formation is on which is uniform. An irregular
arrangement is a "wild" formation.
The part of a sack making machine around which the web of paper is folded and the overlapped edges are pasted to form the tube.
A type of paper machine on which the
web is formed by depositing pulp on the surface of a moving endless wire
screen, called a wire or machine cloth. When the pulp is fed onto this
wire, it is 99% water and 1% fiber. The wire screen permits most of
the water to drain out of the sheet and the fibers have become more
tightly interlocked. When the paper leaves the Fourdrinier wire, it
enters the press section of the paper machine.
A plastic film incorporated into a multiwall sack as a separate ply.
The distance between the top of the product and the top of the sack when the sack is placed upright.
Freight Classification Stamp
An imprint bearing the sack
manufacturer's name or symbol that guarantees that the construction of
the sack meets or exceeds the requirements of the applicable freight
A mixture of various materials that are blended in
the pulp stock suspension from which paper is made. The chief
constituents are the fibrous material or pulp, sizing materials, fillers
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Caliper or thickness expressed as 100 times millage. e.g. 1 mil = 100ga
Paper Highly hydrated pulp made into paper and then super-calendered.
Used as a grease barrier and can be colored or tinted.
A descriptive term for any highly
refined and dense sheet of paper that has been treated or coated to
provide a good barrier to some fats and oils.
Kraft paper tape with a glue or dry adhesive, used in the closure of multiwall sacks. The adhesive is activated by water.
Small dots or bars of paste applied between the plies of a tube in the gusset area.
Print design or lettering occurring in the
gusset of the bag for product identification when bags are filled and
stacked on pallets.
The reverse folds in the sides of square, automatic and sewn multiwall sacks. Not found in flat tube sacks.
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process using printing plates, usually copper or zinc, produced by the
photoengraving process. A reproduction of original artwork having a
gradation of tones. The surface of the plate consists of dots of
various sizes, generally spaced from 40 to 180 per linear inch, which
are capable of rendering not only the extreme lights and darks of a
picture but all gradations in between.
Hands of Stack
A term used to describe a group of sacks
ranging from about 15 to 25 sacks placed in a stacking pattern for
palletizing unfilled sacks.
Heat Reactivation Closure
A closure constructed of
thermoplastic resin allowing it to be sealed with the application of
heat. Primarily used with pinch bottom sacks.
Heat Sealable Sack
A term applied widely to a variety of surface-coated papers that can be sealed by the application of heat.
Heavy Duty Plastic Bag
A plastic bag of single or multiple ply construction, designed to serve as the prime shipping container.
Hot Melt Adhesive
A thermoplastic adhesive composed of
blends of polymers, resins, and/or waxes. The adhesive is liquefied by
heat, applied molten and forms a bond by cooling and solidifying.
The amount of moisture present in the air.
Having the property of readily absorbing atmospheric moisture.
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of a plastic film to shock impact. It is measured by dropping a
weighted round dart onto the film from a given height. Also called Dart
The process of treating a sheet of paper with a liquid so that the treatment penetrates the paper.
A large cylinder on a printing press
over which the paper is threaded. As the inked plate comes around, it
strikes the paper at the point where the inked plate passes over the
Identification marks or symbols printed on a
multi-wall sack, consisting of code numbers, freight classification
stamp, etc. Not part of the brand printing.
Papers that are manufactured for
industrial uses such as impregnating, insulating, and packaging as
opposed to cultural papers or fine papers used for writing and
The amount of ink printed on a sack or bag in relation to the total area of the package available for printing.
That property of a sheet of paper, or other material, which causes it to absorb ink.
Paper whose surface has been chemically
treated to resist the attack of boring insects. The use of such paper
is subject to US FDA regulations.
Dots or bars of paste applied between the walls or plies of a tube during bag manufacture.
Pasted sack bottoms folded in the opposite way from bottoms normally produced on the sack machine.
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Any large roll of paper generally 26 inches or more in diameter that is to be used for converting purposes.
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resisting frictional force required to keep one object moving over
another at a constant speed. The force needed to keep an object moving
once it is started in motion.
A paper made entirely from wood pulp produced
by a modified sulphate pulping process. The paper is coarse and noted
for its strength. The name is obtained from the German word "kraft"
meaning strength. It is usually manufactured on a Fourdrinier machine.
Its natural color is brown, but by using semi-bleached or bleached
sulphate pulp it can produce lighter shades including white. Kraft
paper used for shipping sacks and bags is most commonly made in basis
weights from 25 to 80 lbs.
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coating applied on the printing press over the ink to provide gloss,
protection from ink scuffing, higher slide angle or, in some cases,
lower slide angle.
A combination of two or more sheets of
paper, film or foil bonded together in order to make a sheet stronger or
more resistant to moisture, grease or odor.
In sack manufacturing, the amount of the web necessary
to allow one edge to extend over the other so that they can be joined
by an adhesive to form a tube. Also refers to the paper necessary in
the ends of pasted bags to allow one side of the tube to be folded over
the other to form a pasting area.
Used for lamination or spot pasting of film to kraft paper.
The longest dimension of an unopened sack exclusive of lips or thumb tabs.
The process of printing directly from an inked, raised surface against which the paper is pressed.
A heat-sealed plastic sack inserted inside a paper sack to provide barrier protection for the product packed.
A high basis weight and stiffer natural kraft
paper generally intended for rigid applications such as a corrugated
box. Linerboard is used for roofing shingle wrap and single-wall baler
Particles of fibers that separate or "dust off" from paper during manufacturing or converting operations.
A small ticket attached to a skid or pallet
load of sacks or bags and containing factory order information such as
size, brand, etc. and the count of sacks or bags on the pallet.
The thread that is mechanically tied around the needle thread to form a lock-stitch seam for the sack closure.
The end of a sewn multiwall bag that has not been correctly sewn.
A quantity received and stored at one time such as paper, bags, or rolls.
Low-Stretch Crepe Paper
Paper with only 3 to 7.5 percent crepe for a rough outer surface to improve handling and stacking.
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Creped paper produced on the paper machine, not as a secondary off-machine operation.
The direction of paper parallel to its forward movement on the paper machine. Also called "with the grain."
The finish obtainable on a particular paper
machine without the aid of any added equipment such as water boxes or
A high finish paper made on a Fourdrinier
machine with a Yankee Dryer. The latter gives the paper a smooth,
glossy, high finish on one side.
The temperature at which a solid substance begins to melt under standard conditions.
A very thin coating of metal, usually aluminum, which is vacuum deposited on film and foil.
Micron ( )
Caliper or thickness in metric system 1.0 mil = 25.4 microns.
The caliper of thickness expressed in mils. 1 mil = One thousandth (1/1000) of an inch or 0.001 inch.
The roll of paper as it is received from the
paper mill. Used to distinguish a plain roll from a roll of printed or
Moisture Barrier Sheet
Paper with an ability to resist transmission of water or water vapor.
The percentage of water in a material.
It is usually determined by completely drying a sample at 100 to 105 o
C. (212 to 221o F). The result is expressed as a percentage of the
original weight of the sample.
Moisture Vapor Transmission Rate
The rate of grams of
moisture that will pass through an area of 100 sq in of barrier material
in a 24 hour period expressed as gm/100 sq in/24 hr.
A chemical additive used in paper to prevent or delay the growth of mold.
The resistance of paper to rupture under pressure.
Usually determined on a Mullen tester and expressed in pounds per
square inch. Also referred to as bursting strength.
Multiwall Paper Shipping Sack
A flexible container made
from two to six plies of kraft paper, meeting designated
specifications. The walls or plies may be made up of 40, 50, 60 or 70
lb paper and one or more plies could be a plastic film, foil, or a
DuPont trade name for polyester film.
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National Motor Freight Classification
national tariff published by the American Trucking Association which
sets forth container specifications for all commodities being moved by
common carrier trucks.
Paper that is not bleached, dyed or tinted. Paper that is the color of natural kraft, a light tan or brown.
The thread which is inserted by the needle which passes completely through the sewn sack
The manner in which the walls of a sack fit within
or nest to one another; with correct nesting each wall will bear its
proportionate share of the burden.
Those papers with a pH of 6.5 to 7.5 that
indicated freedom from acid and alkali. Such papers will not cause
corrosion when in contact with metals.
The "line of contact" between two rolls, such as in a printing press or calender stack.
The portion of a sewn valve tube that is cut away
leaving an extension at one corner to be folded into the sack when the
valve is formed. The depth of the notch determines the valve extension
In multiwall bags, the deepness of the notch cut out of the tube.
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The offsetting of the face and back of gusseted open mouth sacks to allow opening the sack for placement on a filling spout.
Off-Set of Print
The unintentional transfer of the printed
image to the back side of the web in a printed roll. This is usually
caused by too much rewind pressure or incomplete drying of the ink.
A method of printing in which plates
receive the ink and transfer the image to a rubber blanket which in turn
prints on the paper. Also referred to as lithography.
The resistance of paper to light transmission.
Open Corner Sack
A type of "intermediate" multiwall sack
between the basic two styles: valve and open mouth. It usually has a
sewn bottom and the top is partially closed by sewing.
Open Mouth Sack
A sewn or pasted sack, factory closed at one end.
The individual who operates a machine and is responsible for the quantity and quality of production from the machine.
Samples of sacks from different runs that may be retained by the manufacturer or sent to the customer.
Perforations occurring over the entire surface of the bag.
Overprint Varnish or Lacquer
In the printing operation, a
special coating applied over the printed areas of a web on the printing
press. This coating can provide gloss, rub resistance, slip
requirements and other special properties.
A sack used to contain another sack, usually used for broken sacks to minimize product loss.
A substance such as chlorate, permanganate,
inorganic peroxide or nitrate that yield oxygen readily to stimulate the
combustion of organic matter. These products are classified as
hazardous materials and must be packaged according to USDOT regulations.
Oxygen Transmission Rate
The rate in cubic centimeters
that pure oxygen will pass through an area of 100 Sq in of barrier
material in 24 hours, expressed as: cc/100sq in/24 hr.
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A portable wooden, plastic or corrugated platform on which material can be stacked and moved as a unit.
The operation of stacking materials on a pallet, manually or mechanically.
A mat of cellulose fibers which is formed by
suspension in water on a wire screen, and which subsequently has had the
water removed by means of a vacuum and heat drying.
A mixture of starches, dextrines or similar
materials with water, used as an adhesive. This type of adhesive is
commonly used in multiwall bag and sack manufacturing.
The stripes of adhesive applied to the longitudinal seams of the sack.
Pasted Open Mouth Sack
A non-gusseted or flat tube sack with a pasted bottom closure. Also referred to as a satchel bottom sack.
Pasted Open Mouth Self-Opening Sack
A gusseted sack with a formed pasted bottom. This sack may be opened with a quick snap, forming a rectangular bottom.
Pasted Open Mouth Stepped-End Sack
A flat or gusseted sack
with the face, gussets and back stepped at different lengths so that
when folded over, the back stepping pattern adheres to the corresponding
surface of the opposite face.
A strip pasted over the longitudinal seam to prevent sifting of the product.
PE Coated Paper
A paper coated with polyethylene
A paper that has been embossed with a pebble pattern. This is often done to make a label, band or wrapper more machineable.
The act of making perforations in a tube or bag
A serrated knife used to perforate each wall of paper prior to separation to make stepped-end tubes.
Small vent holes punched through the walls of a bag to allow air to escape from the bag rapidly during the filling operation.
The degree of acidity or alkalinity on a scale
ranging from 0 to 14. The neutral point is 7.0 with 0 to 7.0 being acid
and 7.0 to 14 being alkaline. A commercially neutral paper has a pH
range of from 6.5 to 7.5.
Printing plates made from a polymer material.
A means of measuring the resistance of paper to fiber separation.
Picking A term for a defect in the printing on a label involving removal of small areas of the coated surface of the paper.
A solid material which, on being reduced to
powder, can be used to color paper and inks. A pigment is insoluble
while a dye is soluble.
A term used to describe the stepped-end
closures of a flat tube or gusseted pasted open mouth sack in which the
stepping pattern of the various plies provides for more sift-resistance
in the ends of the sack and allows the sack, when filled, to form a more
Pinch Bottom Sack
A pasted open mouth stepped end sack.
Small holes in a sack made by
perforation pins to allow the escape of air during packing.
Perforations may be under the valve and/or over the entire surface of
the sack or in a barrier ply only.
Minute holes in a sheet of paper that may be caused either by spaces between the fibers or by foreign particles, or both.
An unprinted bag or sack
A wall of a sack. A single thickness or fold of
paper. Plies are described from the inside ply of the package to the
A generic term for polyolefins, including polyethylene and polypropylene.
A thermoplastic material composed solely of polymers of ethylene abbreviated PE.
A compound formed by the linking together of two
or more monomers. A homopolymer means that the monomers are the same. A
copolymer means that the monomers are different.
A slang term for Mullen or bursting strength.
The characteristic of a sheet of paper that
permits the passage of air through the sheet. A measure of time in
seconds required for the passage of 100 cc of air through one square
inch of paper.
A coating printed on the outer ply of a
multiwall bag in an area that will be contacted by vacuum cups of
automatic bag placement equipment.
A term used to identify small bags holding up to 10 pounds.
Kraft tape, coated on one side
with a pressure-sensitive material and on the second side with a release
agent. Requires only brief pressure at room temperature to use. Some
pressure sensitive tapes are supplied with a release backing of paper
that is removed at the time of use.
A chemical coating sometimes applied to a substrate to enhance its ability to accept another substrate.
A sample bag or plate proof, bearing a print
number ink shade and register, the likeness of which is to be reproduced
on the printing press.
The pressure required to transfer the ink
from the printing press etched roller to the printing plate and from
the printing plate to the web being printed. This affects the sharpness
of the printed image on the substrate.
A roll of paper or other material that has been printed.
Print Roll Ticket T
he identification ticket attached to each print roll as it leaves the printing press.
The property of a paper or other material that determines how well the material can be printed.
A test print or trial impression in the printing process that is taken for examination or correction.
Holes punched in multiwall sacks to allow
product to breath. Distinguished from perforation holes in which a
sharp instrument pierces holes in the paper, but removes no material in
the process. Punched holes remove material equal to the diameter of the
A measure of the force required to push a probe through a packaging material.
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A DuPont Trade Named special chemical treatment applied internally or to surface of paper to provide water repellency
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A term used to denote 500 sheets of industrial paper 24" x 36" or 3000 square feet of paper.
To correct or repair bags or sacks incorrectly made.
A term applied to the untrimmed roll of paper of full machine width, wound on a large shaft a the dry end of the paper machine.
In printing, the exact placing of successive
colors as they are printed by the sequential printing stations over or
adjacent to each other on the web.
The normal finish on multiwall paper, neither smooth or rough.
The amount of moisture in the air at a
given temperature, expressed as a percentage of the total amount of
moisture the air could hold at that temperature.
In printing, the total circumference of the printing press plate cylinder with a printing plate of correct thickness in place.
A machine to wind paper or other materials from one roll to another. Also called a winder.
A cord, thread or tape used to open a sewn sack without tearing the sack. Sometimes called a rip cord or tear tape.
Printed paper on a roll.
The width of material wound in a roll.
A sizing material made from pine resin that is frequently added or applied to paper to render it moisture resistant.
The process of printing from a cylindrical surface having an etched or recessed, design.
Multiwall paper have a rough or course textured surface or finish.
Rug resistance T
he resistance of ink to smearing or transfer when rubbed against itself or another material.
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non-rigid container made from paper or other flexible material. It is
made by forming a tube and closing one or both ends but leaving an
opening through which the material to be carried in the container is
introduced. Preferably used to describe packages of 20 pounds net
weight or above.
DuPont trade name for PVDC coating.
A pasted bottom which forms a flat base when filled.
A crease placed near the top or bottom of the sack for easy forming in opening or closing operations. Also called creased top.
Paper sheet reinforced with open mesh, textile or glass fiber threads
The raising of the fibers on the surface of a
paper or paperboard when one piece is rubber against another or comes in
contact with a rough surface.
The force required to separate a seal.
Seals are made under standard conditions of pressure, temperature, and
dwell time. Seal strength is usually expressed as the grams of force
required to separate a one inch wide seal.
The property of a material that renders it capable of being fused or sealed to itself by the application of heat and pressure.
he layer of a packaging material that seals to another layer or itself when heat and pressure are applied.
The overlapping and pasting portion which runs the entire length of the tube from which a sack is formed.
The adhesive used in forming the seam of a paper tube.
Scrap or waste paper that is used a second time for making paper.
Valves in multiwall sacks that close automatically from the pressure of the contents.
The "saw-tooth" edge at the end of a paper sack.
The thread used to close the ends of sacks in sewn closures.
A method of closing filled sacks with a special sewing machine.
Sewn Open Mouth Sack
A gusseted or flat tube sack, factory sewn with thread or tape on one end.
The cut on bag tubes made by a knife with a straight edge.
Slits at the end of a tube to give shingling
of walls at pasted ends improved sift resistance as opposed to flush
cutting or cutting all walls together.
Shipping Sack Kraft
Normally 40 to 60 pound basis weight kraft paper manufactured specifically to meet the requirements of shipping sack packaging.
A very small bundle of fibers in paper that have not been properly separated by cooking in the pulping operation.
A film, usually polyethylene, designed to
shrink in each direction when heat is applied and when cooled, retains
strength properties. Used to stabilize pallet loads of shipping sacks.
A longitudinal seam placed at or near the edge of the sack to avoid having the seam in the printed area.
Sift Proof Bottom
A bottom formation which prevents loss of contents by sifting,
Silicone Release Paper
A coating of silicone on kraft
paper or on polycoated kraft paper to provide release from sticky
products such as synthetic rubber or asphalt.
Size or Sizing
Chemicals that are added to paper to render them resistant to moisture. Size may be added at the size press or internally.
Located between dryer sections on a paper
machine the size press consists of a tank and a pair of press rolls.
The sizing material is applied to the paper as it passes between the
rolls. The pressure between the rolls determines the amount of material
applied to the sheet.
A paper that has been treated internally or on the surface to resist the penetration of liquids.
A low platform on which material is loaded in order to store or transport it. Sometimes referred to as a pallet.
That property of the outer surface of a bag or sack that prevents it from sliding.
A loosely filled bag
A separately applied piece of paper and/or plastic film in the valve opening to prevent sifting.
The distance a tuck-in sleeve extends out
of the valve, measured from the edge of the valve to the outside or
mouth end of the sleeve.
A single ply insert extending through the valve opening into the multiwall sack to prevent sifting.
Sleeve, Tuck-In A
n outer sleeve extension on a valve sack that is folded and tucked in by hand after the sack has been filled.
The angle at which paper will start sliding
when in contact with another piece of the same paper and under standard
A sheet of material that is inserted between
two surfaces to separate or protect them. Can be used in place of a
pallet, with proper push-pull attachment to a forklift for loading and
Small cuts made in the paper parallel to the sack edge to aid in forming the ends.
Dust from the slitter that may be caught up
in the moving web of paper and may cause trouble in subsequent finishing
or printing operations.
Soft End Roll
A roll of paper on which the ends are softer or looser than the rest of the roll.
Ends of sewn sacks in which the bound over tape
is not drawn tightly over the ends of the tube or sewn too close to the
Softening Point T
he temperature at which a plastic film
becomes too soft to withstand stress or begins to block. High packing
temperatures (filling sacks with hot products) can have an adverse
effect on some films.
The joining together of two lengths of material by
their ends. Used to repair a break or to attain greater continuous
length in a roll. Splices are made using either glues or adhesive
A marker put in the edge of a roll to show the location of a splice. Also called a flag.
A label that covers only a portion of the
package. Usually refers to a small supplementary label. Sometimes used
for small quantities of a specific product for use with a standard
The pasting together of the walls of multiwall
sacks with small spots of adhesive near the open end. This facilitates
opening the bag and prevents product from getting between the plies
A pasted closure for a filled sack made by spraying adhesive through an air brush.
A gusseted bag with a machine formed pasted
bottom. Sometimes referred to as an SOS or Self Opening Square or
Automatic bag. The bag may be opened with a quick snap forming a
A label, band or wrapper that is square or rectangular, usually cut on a guillotine cutter.
Gussets formed so that edges are slightly offset with both edges able to be seen from one side.
The resisting frictional force required to
start an object to move when in contact with another object also at
rest. The initial sliding force of an object on another.
The electrical charge that sometimes
collects on paper, film and other materials when in contact with other
substances. It is most evident at low relative humidity levels and may
cause undesired sparking.
Stepped-End Open Mouth Sack
A flat or gusseted sack with
the face, gussets and back stepped at different lengths so that a flap
or extension of the front, on one end of the bag tube and a flap on the
back surface of the opposite end is produced. In the bag plant, hot
melt adhesive is applied to the flap at the bottom of the bag, the flap
is folded over the opposite surface and pressure applied to complete the
closure. Hot melt adhesive also is applied to the flap on the open end
of the bag in the bag plant, but the flap is not folded. After the bag
is filled, the bag is closed on a pinch bottom sealer that reactivates
the hot melt adhesive, folds the end flap over the opposite face and
applies compression to complete the closure.
A tube in which each ply is cut
individually in a stepped pattern rather than all plies cut together and
straight across. Successive plies extend, one beyond the other, so
that when the bag is pasted shut, each ply is pasted to itself.
The amount of extension or elongation of a paper
or film when under tension. Usually measured by tensile test equipment
and reported as a percentage of elongation before the sheet breaks.
A copolymer film with modifiers that impart a
high degree of elasticity. When stretched around a bundle or pallet
load under tension less than its elastic limit, its restoring forces
will exert tension on the bundle or load it contains.
An incomplete roll of material of small diameter. Also called a butt roll.
Any material such as paper, film and foil to which adhesives, inks or coating are applied
Super Calendered Paper
A paper with a very smooth finish
obtained by running the paper through a special finishing machine. Such
a finishing machine consists of alternative hard and soft rolls while a
conventional finishing machine or calender stack has only hard rolls.
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Adhesives, inks, lacquers, varnish and other coatings that impart a
tacky or sticky characteristic to the substrate, especially if not
properly applied or dried.
The inclusion of a tag in the closure, either at
the time of sack manufacture or when the filled sack is closed. Usually
done with sewn closures.
A narrow band of paper, generally creped, folded over the ends of a bag and sewn to the bag to form the closure.
Tape Over Stitching
Tape applied after the bag has been
sewn closed in order to cover the stitch line at the bag closure to
prevent sifting and improve barrier properties. Wet adhesive, hot melt,
or heat sealed thermoplastic coated tape can be used.
Tape Top Closure
The sewn closure of filled sacks incorporating bound over tape.
A narrow tape pasted along the inside of a bag to provide a quick and easy opening feature.
The force, in grams, required to tear a sample of paper under standard conditions.
The force, in lbs/inch of width, required
to break a paper strip of a specified width and length under specified
conditions of loading.
A small, semi-circular cut made at the top center of a paper bag to facilitate opening of the bag.
The allowable variation from specified dimensions of a package
The upper end of a bag or sack when viewed with the
printing in an upright position. Frequently open mouth bags are closed
at the top end in the factory in order to provide special features such
The printing of a subsequent color of ink over
another in a satisfactory manner that does not show the first color.
The first color printed must be lighter than subsequent colors in order
to be trapped by the darker color.
Papers that have functional characteristics
added through special treatment. Among the most common are: Insect
Resistant, Mold Resistant, Silicone (release) coated, clay coated, flame
he widest sheet of paper, after removal of the
deckle edges, that can be made on a given paper machine. Also refers to a
true cut to an exact size by cutting away edges of paper in a web or
The length of the tube of paper or other material before the sack is ended.
The forming of continuous webs of paper into a
cylinder on a bag-making machine and then cutting to length to produce a
tube for a given bag size.
A sleeve which extends out of the valve and which may be folded and tucked into the valve after filling the bag.
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A term applied to paper or pulp that has not been treated with bleaching agents.
Uniform Freight Classification
A national tariff published
by the railroad industry that sets forth container specifications for
all commodities being moved by rail.
Universal Product Code
A ten to 14 digit code printed on
packages that uniquely identifies the product and package size and
permits a photocell to read and record the product for automatic
A term applied to papers which have no sizing added.
The resistance of a material to degradation
from ultra-violet rays in sunlight, usually expressed in terms of hours
at which a given percent of tensile strength is retained.
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An opening folded into a corner of a sack through which the sack is filled.
The distance that the valve notch extends beyond the normal valve in-fold.
A strip of material pasted into the valve opening to make the valve stronger and more sift-resistant.
Perforations placed beneath the valve of a multiwall sack to release air pressure during filling.
The identification of location of the valve
when facing the front of the bag, the face opposite the longitudinal
seam, when the printing is upright. Referred to as upper left hand
(ULH), upper right hand (URH), lower left hand (LLH) or lower right hand
A sack whose top and bottom are factory closed, with the exception of a small opening at one corner called a valve.
The internal, lay flat, dimension of the opening in the corner of a valve sack.
Holes punched in multiwall plies to allow the package to breathe when the product is packed.
The property of a fluid that offers resistance
to flow or motion within itself. The higher the viscosity, the thicker
or heavier the liquid.
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Any one of the sheets of paper or other materials making up the plies of a sack.
A property imparted to certain papers to
shed water. Often recommended for use where the sack is exposed to
water droplets or water spray.
Water Resistant Paper
Paper that has been impregnated, coated or laminated to resist the penetration of water.
Water Vapor Transmission Rate
A term used to express the
weight of water transmitted per unit of time, per unit area, when the
barrier separates a dry atmosphere from an atmosphere of specified
relative humidity and temperature. The grams of moisture that will pass
through and area of 100 sq in of material in a 24 hour period,
expressed as gm/100 sq in/24 hr.
An adhesive class of synthetic resin
or latex base designed to be used in sack constructions with water
resistant or wet strength paper. These adhesives are resistant to
failure when soaked in water.
Wax Laminated Kraft
Two sheets of kraft held together with wax.
Glassine paper treated with waxes to make it more transparent and more resistant to moisture and water vapor.
Kraft paper that has been treated with wax to give it resistance to moisture, water, and grease.
Weather Resistant Paper
Highly sized and/or highly finished paper used as an outer wall in sacks to help repel water.
The material from a roll as it moves through a converting machine.
The printed amount of weight of contents which a filled sack or bag will contain.
A converting operation in which the paper is moistened and passed over a roll equipped with a doctor blade.
Wet Strength Paper
Paper made from pulp treated with urea
formaldehyde or other materials to retain a substantial part of its
original dry strength when saturated with water.
For an empty sack, the measurement from edge to edge. Often called the face width.
The side of the paper web that was in contact with the wire on the wet end of the paper machine during manufacture of the paper.
A wire covered in paper or plastic that is used to close some consumer bags.
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The number of square inches per pound of material or square meters per kilogram of material.
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