Paper Products Glossary

Base paper (Body Stock): The base stock for plain or decorated coated papers and boards. It may be uncoated or pre-coated on the paper machine.

Bond paper: Originally a cotton-content writing or printing paper designed for the printing of bonds, legal documents, etc., and distinguished by superior strength, performance and durability. The term is now also applied to papers such as letterhead, business forms, social correspondence papers, etc.

Construction paper: Sheathing paper, roofing, floor covering, automotive, sound proofing, industrial, pipe covering, refrigerator, and similar felts.

Containerboard: Solid fiber or corrugated and combined board used in the manufacture of shipping containers and related products.

Corrugated container: The most common type of box manufactured from containerboard, layers of linerboard and one layer of medium. The layers are combined on a corrugator, a machine that presses corrugations into the medium and laminates a layer of linerboard to each side. The sheets are folded, printed, and glued or stapled to make a finished box.

Corrugating medium: A paperboard used by corrugating plants to form the corrugated or fluted component in making corrugated combined board, corrugated wrapping, and the like. It is usually made from chemical or semi-chemical wood pulps, straw, or reclaimed paper stock on cylinder or fourdrinier machines.

Chipboard: A paperboard used for many purposes. It is normally made from a paper stock with small thickness.

Cotton fiber: Paper that contains 25 percent or more cellulose fibers derived from cotton linters and cotton or linen cloth cuttings.

Cover paper: Any wide variety of fairly heavy plain or embellished papers, which are converted into covers for books, catalogs, brochures, pamphlets, etc. Characterized by good folding qualities, printabililty, and durability.

Cylinder paper machine: One of the principal types of papermaking machines, characterized by the use of wire-covered cylinders or molds. The pulp fibers are formed into a sheet on the mold as the water drains through, leaving the fibers on the cylinder face. The wet sheet is couched off the cylinder onto a felt, which is held against the cylinder by a couch roll. A cylinder machine may consist of one or several cylinders, each supplied with the same or with different kinds of stock. In the case of a multi-cylinder machine, the webs are successively couched one upon the other before entering the press section. This permits wide latitude in thickness or weight of the finished sheet, as well as in the kind of stock used for the different layers of the sheet. The press section and the dry end of the machine are essentially the same as those of other types of machines.

Deinking: A process in which most of the ink, filler and other extraneous material is removed from printed and/or unprinted recovered paper. The result is a pulp which can be used, along with varying percentages of wood pulp, in the manufacture of new paper, including printing, writing and office papers as well as tissue.

Digester: A cylindrical or spherical vessel used to treat cellulosic materials with chemicals under elevated pressure and temperature to produce pulp for papermaking.

Envelope paper: Any uncoated printing-writing paper used in the manufacture of envelopes. Desirable properties include smooth fold, strength at crease, good printability, and lack of tendency to curl.

  • Brown kraft envelope: Fourdrinier machine-finished or machine-glazed paper usually made from unbleached sulfate pulp or dyed bleached sulfate pulp, used in the manufacture of envelopes when strength is a primary requirement.
  • White kraft envelope: Fourdrinier machine-finished or machine-glazed paper usually made from bleached sulfate pulp, in white and colors. It is used in the manufacture of envelopes when strength is a primary requirement.
  • Woven envelopes: General purpose paper, either white or colors, used primarily for commercial purposes. Also refers to commodity envelope base stock. Bond, cotton fiber, text grades, and similar distinctive grades used for envelope end use are not included in this category; rather they are included with their unique grades.

Form bond: A lightweight commodity paper designed primarily for printed business forms. It is usually made from chemical wood and/or mechanical pulps. Important product qualities include good perforating, folding, punching, and manifolding properties. The most common end use for this grade is carbon-interleaved multi-part computer printout paper, which is marginally punched, crossperforated, and fanfolded.

Fourdrinier paper machine: Named after its sponsor, with its modifications and the Cylinder machine, comprise the machines normally employed in the manufacture of all grades of paper and board. The fourdrinier machine, for descriptive purposes, may be divided into four sections: the wet end, the press section, the drier section, and the calender section. In the wet end, the pulp or stock flows from a headbox through a slice onto a moving endless belt of wire cloth, called the fourdrinier wire or wire, made of brass, bronze, stainless steel, or plastic. The wire runs over a breast roll under or adjacent to the headbox, over a series of tube or table rolls or more recently drainage blades, which maintain the working surface of the wire in a plane and aid water removal. The tubes or rolls create a vacuum on the downstream side of the nip. Similarly, the drainage blades create a vacuum on the downstream side where the wire leaves the blade surface, but also performs the function of a doctor blade on the upstream side. The wire then passes over a series of suction boxes, over the bottom couch roll (or suction couch roll), which drives the wire and then down and back over various guide rolls and a stretch roll to the breast roll. The second section, the press section, usually consists of two or more presses, the function of which is to mechanically remove further excess water from the sheet and to equalize the surface characteristics of the felt and wire sides of the sheet. The wet web of paper, which is transferred from the wire to the felt at the couch roll, is carried through the presses on the felts; the texture and character of the felts vary according to the grade of paper being made. The third section, the drier section, consists of two or more tiers of driers. These driers are steam-heated cylinders, and the paper is held close to the driers by means of fabric drier felts. As the paper passes from one drier to the next, first the felt side and then the wire side comes in contact with the heated surface of the drier. As the paper enters the drier train approximately one-third dry, the bulk of the water is evaporated in this section. Moisture removal may be facilitated by blowing hot air onto the sheet and in between the driers in order to carry away the water vapor. Within the drier section and at a point at least 50 percent along the drying curve, a breaker stack is sometimes used for imparting finish and to facilitate drying. This equipment is usually comprised of a pair of chilled iron and/or rubber surfaced rolls. There may also be a size press located within the drier section, or more properly, at a point where the paper moisture content is approximately five percent. The fourth section of the machine, the calender section, consists of from one to three calender stacks with a reel device for winding the paper into a roll as it leaves the paper machine. The purpose of the calender stacks is to finish the paper, i.e., the paper is smoothed and the desired finish, thickness or gloss is imparted to the sheet. The reel winds the finished paper into a roll, which for further finishing either can be taken to a rewinder or, as in the case of some machines, the rewinder on the machine produces finished rolls directly from the machine reel. The wire, the press section, the several drier sections, the calender stacks, and the reel are driven so that proper tension is maintained in the web of paper despite its elongation or shrinkage during its passage through the machine. There are two modifications of the fourdrinier in use, known as the Harper and the Yankee or M.G. machine, which in principle are similar to the fourdrinier machine.

Free Sheet: Paper free of mechanical wood pulp or paper made from pulps having a high freeness (the rate at which water drains from a stock suspension through a wire mesh screen or a perforated plate).

Grade: (1) A class or level of quality of a paper or pulp which is ranked, or distinguished from other papers or pulps, on the basis of its use, appearance, quality, manufacturing history, raw materials, or a combination of these factors. Some grades have been officially identified and described; others are commonly recognized but lack official definition. (2) With reference to one particular quality, one item (q.v.) differing from another only in size, weight, or grain; e.g., an offset book paper cut grain long is not the same grade as the same paper cut grain short.

Insulating board: A type of board composed of some fibrous material, such as wood or other vegetable fiber, sized throughout, and felted or pressed together in such a way as to contain a large quantity of entrapped or "dead" air. It is made either by cementing together several thin layers or forming a nonlaminated layer of the required thickness. It is used in plain or decorative finishes for interior walls and ceilings in thicknesses of 0.5 and 1 inch (in some cases up to 3 inches) and also as a water-repellent finish for house sheathing. Desirable properties are low thermal conductivity, moisture resistance, fire resistance, permanency, vermin and insect resistance, and structural strength. No single material combines all these properties but all should be permanent and should be treated to resist moisture absorption.

Kraft bag paper: A paper made of sulfate pulp and used in the manufacture of paper bags. It normally has a greater bulk and a rougher surface than the usual kraft wrapping paper.

Kraft wrapping paper: A paper made essentially from wood pulp produced by a modified sulfate pulping process. It is a comparatively coarse paper particularly noted for its strength, and in unbleached grades is primarily used as a wrapper or packaging material. It can be watermarked, striped, or calendered, and it has an acceptable surface for printing. Its natural unbleached color is brown but by the use of semibleached or fully bleached sulfate pulps it can be produced in lighter shades of brown, cream tints, and white. In addition to its use as a wrapping paper, it is converted into such products as: grocery bags, envelopes, gummed sealing tape, asphalted papers, multiwall sacks, tire wraps, butcher wraps, waxed paper, coated paper, as well as specialty bags and sacks.

Mechanical paper: Papers other than newsprint, made with substantial proportions of mechanical pulp, and used for printing or converting.

Newsprint: A lightweight paper, made mainly from mechanical wood pulp, engineered to be bright and opaque for the good print contrast needed by newspapers. Newsprint also contains special tensile strength for repeated folding. It does not include printing papers of types generally used for purposes other than newspapers such as mechanical printing papers for catalogs, directories, etc.

Napkin Stock: Lightweight paper or crepe paper that is used at a meal to wipe the fingers or lips and to protect garments, or to serve food on.

Offset paper: Paper designed for use in offset lithography. Important properties include good internal bonding, high strength, dimensional stability, lack of curl, and freedom from fuzz and foreign surface material. Used on both sheet-fed and web presses. This is commodity offset.

  • Premium/Opaque offset: High quality offset markedly brighter and more opaque than Offset Paper as defined above. It is usually produced in smooth and vellum finishes and may have a companion cover paper. This is a mid-range product between Offset Paper and higher quality papers in the Text and Cover category.

Packaging papers: These papers are used to wrap or package consumer and industrial products such as grocer's bags and sacks, shopping and merchandise bags, and multiwall shipping sacks used for shipping such products as cement, flour, sugar, chemicals and animal food. "Specialty" packaging papers are used for cookies, potato chips, ice cream, and similar products.

Paper: The name for all kinds of matted or felted sheets of fiber (usually vegetable, but sometimes mineral, animal or synthetic) formed on a fine screen from a water suspension. Paper derives its name from papyrus, a sheet made by pasting together thin sections of an Egyptian reed (Cyperus papyrus) and used in ancient times as a writing material. Paper and paperboard are the two broad categories of paper. Paper is usually lighter in basis weight, thinner, and more flexible than paperboard. Its largest uses are for printing, writing, wrapping, and sanitary purposes, although it is employed for a wide variety of other uses.

Paperboard: One of the two subdivisions of paper. The distinction is not great, but paperboard is heavier in basis weight, thicker, and more rigid than paper. Sheets 12 points (0.012 inch) or more in thickness are classified as paperboard. There are exceptions. For example, blotting papers, felts, and drawing paper in excess of 12 points are classified as paper, while corrugating medium, chipboard, and linerboard less than 12 points are classified as paperboard.

  • Bleached board/Bleached paperboard: A general term covering any board composed of 100 percent bleached fiber. Examples of uses of this type of paperboard are milk and juice cartons, drink boxes, cosmetic boxes, and many frozen food boxes.
  • Bleached packaging paperboard: A paperboard made from approximately 85 percent virgin bleached chemical pulp.
  • Boxboard: The general term designating the type of paperboard used for fabricating boxes. It may be made of wood pulp or paper stocks or any combinations of these and may be plain, lined, or clay-coated.
  • Clay-coated boxboard: A grade of paperboard that has been clay-coated on one or both sides to create whiteness or smoothness. It is characterized by brightness, resistance to fading, and superior printing surface. Colored coatings may also be used and the body stock for coating may be any variety of paperboard.
  • Folding boxboard: A type of paperboard suitable for making folding cartons. Folding boxboard can be made from a variety of raw materials on either a cylinder machine or a fourdrinier machine. The qualities of this boxboard permit it to be scored and folded, and-depending on the printing requirements-can have variable surface properties. This classification of paperboard includes such products as clay-coated boxboard, white patent coated news, manila lined news, and fourdrinier bleached kraft board.
  • Linerboard: A paperboard that is used as the facing material in the production of corrugated and solid fibre shipping containers.
  • Medium: The paperboard grade used to form the inner layer of corrugated board. It can be made of recycled material or wood pulp.
  • Recycled paperboard: A type of paperboard manufactured using 100 percent recovered paper. Products include linerboard and corrugating medium; folding boxboard (both clay-coated and uncoated) used for packaging cereal and other food products, laundry detergent, and other dry products; set-up boxboard, used for candy boxes, shoe boxes, perfume boxes, and similar products. Recycled paperboard is also used for many non-packaging products, such as gypsum wallboard facing; tubes, cans and drums; and matches, tags, tickets, game boards, and puzzles.
  • Solid bleached kraft: This type of paperboard is used primarily in clay-coated folding boxes for such products as frozen foods, butter, ice cream, and cosmetics, as well as in cartons for milk, juice and other moist, liquid and oily foods. Additional uses include plates, dishes, trays, and cups.
  • Unbleached kraft: The primary grade here is linerboard, used as facing material for corrugated boxes. Unbleached kraft folding boxboard is usually clay-coated. The largest market for this type of paperboard is beverage carriers. Other products include tubes, cans, and drums.
  • Wet machine board: A very thick paperboard, used for bookbinders, shoeboard, automotive board, chair seat backing, coaster board, and the like.

Printing-Writing: Any paper suitable for printing, such as book paper, bristols, newsprint, writing paper, etc.

Fine paper: A broad term including printing, writing, and cover papers, as distinguished from wrapping papers and paper not generally used for printing purposes, which are generally referred to as coarse papers.

Pulp: Fibrous material prepared from wood, cotton, grasses, etc., by chemical or mechanical processes for use in making paper or cellulose products.

  • Chemical pulp: Pulp obtained by digestion of wood with solutions of various chemicals. The paper produced is strong and less prone to discoloration. The pulp yield is lower in this process. The principal chemical processes are the sulfate (kraft), sulfite, and soda processes. Chemical pulps are used to make shipping containers, paper bags, printing and writing papers, and other products requiring strength.
  • Brown pulp: A mechanical pulp made from wood, which is steamed before grinding. The color-bearing, non-cellulosic components of the wood remain with the pulp. The pulp is generally used for wrapping and bag paper.
  • Dissolving pulp/special alpha: A special grade of chemical pulp usually made from wood or cotton linters for use in the manufacture of regenerated or cellulose derivatives such as acetate, nitrate, etc.
  • Fluff pulp: A chemical, mechanical or combination chemical/mechanical pulp, usually bleached, used as an absorbent medium in disposable diapers, bedpads and hygienic personal products. Also known as "fluffing" or "comminution" pulp.
  • Kraft (sulfate) pulp: Term refers to a strong papermaking fiber produced by the kraft process where the active cooking agent is a mixture of sodium hydroxide and sodium sulfide. The term "kraft" is commonly used interchangeable with "sulfate" and is derived from a German word which means "strong."
  • Market pulp: Wood, cotton, or other pulp produced for, and sold on, the open market, as opposed to that which is produced for internal consumption by an integrated paper mill or affiliated mill.
  • Mechanical pulp: Any wood pulp manufactured wholly or in part by a mechanical process, including stone-ground wood, chemigroundwood and chip mechanical pulp. Paper made by this process is opaque and has good printing properties, but it is weak and discolors easily when exposed to light due to residual lignin in the pulp. Uses include newsprint printing papers, specialty papers, tissue, toweling, paperboard and wallboard.
  • Sulfite pulp: A papermaking fiber produced by an acid chemical process in which the cooking liquor contains an excess of SO2. The sulfite liquor is a combination of a soluble (such as ammonium, calcium, sodium, or magnesium) and sulfurous acid. Calcium was commonly used in the past but is not as widely used now because of chemical recovery and pollution abatement problems.
  • Unbleached pulp: Pulp not treated with any bleaching agents.

Recovery boiler: In wood pulping, a unit for concentrating black liquor to a stage where the residual carbon is then burned out and the inorganic sodium salts melted and recovered.

Recycled fiber: Cellulose fiber reclaimed from waste material and reused, sometimes with a minor portion of virgin material, to produce new paper.

Recycled paper: Usually old newspaper or waste paper used with very little refining, often with mechanical or semi-bleached kraft.

Solid Bleached Bristols: A heavier printing paper produced on cylinder or fourdrinier paper machines in whites and colors. It is also used for conversion into office products and school supplies. Examples of bristols include index cards, tags, file folders, boarding passes, business cards, and postcards. Coated bristols are generally used for menus and as covers for booklets or pamphlets.

Specialty: Grades of paper and/or paperboard made with specific characteristics and properties to adapt them to particular uses. Also refers to grades made in a given mill that are not the primary products of that mill.

Specialty Extrusion coating: A coating, which is applied by means of extrusion, either simultaneous with or separate from the actual extrusion itself. Coatings of the extrusion type are normally quite quick, solvent based and applied at elevated temperatures, usually associated with plastics.

Specialty Industrial paper: Papers intended for industrial uses, as opposed to those for cultural or sanitary purposes. Paper and board of all thickness and fiber types designed for special uses and manufactured to exact customer specifications. Includes abrasive paper, electrical insulation, filter paper, and similar grades.

Text paper: A paper of fine quality and texture for printing. Text papers are manufactured in white and colors, from bleached chemical wood pulp or cotton fiber content furnishes with a decked or plain edge, and are sometimes watermarked. They are made in a wide variety of finishes, including antique, vellum, smooth, felt-marked, and patterned surfaces-some with laid formations. Designed for advertising printing, the principal use of text papers is for booklets, brochures, fine books, announcements, annual reports, menus, folders, etc.

Thin papers: Includes carbonizing, cigarette, bible and similar papers.

Tissue: A general term indicating a class of papers which are characteristically gauzy in texture and, in some cases, fairly transparent. They may be glazed, unglazed, or creped, and are used for a variety of purposes. Examples of different types of tissue papers include sanitary grades such as toilet, facial, napkin, towels, wipes, and special sanitary papers. Desirable characteristics in these types of tissue papers are softness, strength, and freedom from lint. Other examples of tissue papers are decorative and laminated tissue papers and crepe papers, often used in gift wrapping and to decorate. Desirable characteristics here are appearance, strength, and durability. Tissue papers are divided into three major categories: At-Home (or Consumer), Away-from-Home (or Commercial & Industrial), and Specialty.

  • At-Home products: Also known as Consumer Products, these are the tissue products you purchase in the grocery store, the convenience store and mass merchandisers for use in your home and include toilet paper and facial tissue, napkins and paper towels, and other special sanitary papers.
  • Away-from-Home products: Also known as Commercial & Industrial Tissue, these are the products that serve markets such as hospitals, restaurants, businesses, institutions, and janitorial supply firms.
  • Facial tissue: The class of soft, absorbent papers in the sanitary tissue group. Originally used for removal of creams, oil, and so on, from the skin, it is now used in large volume for packaged facial tissue, toilet paper, paper napkins, professional towels, industrial wipes, and for hospital items. Most facial tissue is made of bleached sulfite or sulfate pulp, sometimes mixed with bleached and mechanical pulp, on a single-cylinder or fourdrinier machine. Desirable characteristics are softness, strength, and freedom from lint.
  • Paper Towels: Paper toweling is folded or rolled sheets used for drying or cleaning where quick absorption is required. Paper towels are often embossed during the converting process for additional cleaning strength or absorption. Paper towels can be made from chemical pulp and recycled fiber or a combination of the two.
  • Specialty tissue papers: These types of tissue papers are often high-end, decorative papers that are glazed, unglazed, or creped, and include wrapping tissue for gifts and dry cleaning, as well as crepe paper for decorating.

Wallboard: (1) A type of fibreboard composed of a number of layers of chip, binders, or pulpboard, molded or pasted together and generally sized, either throughout or on the surface. It may also be nonlaminated and homogenous in nature. Wallboard is generally 3/16 to 1/4 of an inch in thickness. (2) A general term used to indicate a composition material used in the construction of partitions, side walls, and ceilings in interior construction; it is made generally of waste papers, wood pulp, or wood or other materials. Also known as gypsum wallboard and sheetrock.