This page contains list of various types of pulp based on their pulping process, raw material used or type of bleaching etc. All plant material are basically consist of Cellulose Fiber, Hemicellulose and Lignin, which bind cellulose fibers together. Pulping is nothing but breaking/removing lignin to separate fibers. Lignin is physically and chemically weaker than cellulose fiber. Hence when a physical force or chemical is applied to plant (wood, grass, straw, rag etc.), lignin breaks down faster than cellulose. Heat also weaken lignin faster than cellulose fiber.
So pulping processes varies from complete mechanical to complete chemical and any combination in between.
1. Based on Pulping Process
2. Based on Raw Material
3. Based on Bleaching
4. Based on Yield
5. Based on Fiber Length
- Abaca (Manila Hemp) Pulp
- Pulp made from abaca (manila hemp). Abaca pulp exhibits very high tensile and tear strengths, high viscosity and high porosity. These properties make it the preferred raw material for the production of dielectric, bank note, vacuum bag, tea bag and the full range of filtration papers, as well as various wet laid non-wovens. It is also used in the production of various art, decorative and vellum papers.
- Acetate Pulp
- A highly purified (high alpha cellulose) pulp made especially to be dissolved in acetic acid, acetic anhydride and sulfuric acid to make acetate rayon and acetate fiber. For more detail view Cellulose Acetate Polymer - GAMA
- Acid Sulfite Dissolving Pulp
- Dissolving grade pulp made using sulfite pulping process.
- Agricultural Residue Pulp
- Pulp made from agricultural residue such as straw, bagasse etc.
- Alkaline Peroxide Mechanical Pulping (APMP)
- Pulping sequence: Soaking of wood chips in alkaline solution, washing, peroxide treatment and Refining.
- Alkaline Pulping
- Pulping by alkaline solutions of sodium hydroxide, with or without sodium sulfide. Without sodium sulfide it is called soda process and with sodium sulfide it is known as Kraft or sulfate process.
- Alpha Pulp
- A specially processed, high alpha cellulose content, chemical pulp. It is also called dissolving pulp.
- Aspen Hardwood Kraft Pulp
- Aspen wood has a relatively low lignin content compared to other pulped hardwoods which makes the pulp easier to bleach. Bleached ECF pulps are available both at a standard brightness level(90% ISO) and sometimes higher brightness levels can be obtained(91-92% ISO). Like birch kraft, Aspen kraft pulps refine quickly producing a dense, smooth paper, but with less strength compared to birch pulp.
- Aspen kraft pulp can be used in a variety of printing grades and is specifically useful where a higher brightness is required. Its high smoothness characteristics are particularly suited for coated papers to be gravure printed.
- Typical properties of Aspen hardwood kraft pulp fiber.
- Fiber Length: 1.0-1.3 mm Fiber Width: 18-19 µm Wall Thickness: 2.0-3.0 µm Fiber Coarseness: 86 micro g/m
- Bagasse Pulp
- Pulp made from bagasse. (Bagasse is sugarcane residue left after extracting the juice)
- Bamboo Pulp
- Pulp made from bamboo, a grass native to Asia.
- Birch Hardwood Kraft Pulp
- Birch hardwood kraft pulps are thin walled and the pulped wood has a relatively high hemicellulose content. These pulps refine quickly, producing a pulp which tends to be lower in opacity and bulk compared to eucalyptus hardwood kraft pulps, but higher in burst strength and tensile.
- Occasional poor sheeting of birch pulps at the pulp mill can result in the formation of hard fiber bundles. If such fiber bundles are present in the paper furnish, they can cause transparent spots (sometimes called “windows”, or “shiners” or “fisheyes”) when the paper is calendered. Such fiber bundles can also cause uneven dyeing in colored papers. Birch kraft pulps are often used interchangeably with other hardwood kraft pulps such as eucalyptus krafts in mixed softwood/hardwood furnishes. Typically birch pulps have been used in paper grades where extra tensile/burst strength and a good formation is required. Birch pulps are ideally suited for lightweight coated and uncoated “woodfree” printing papers and for coated silicone release papers, where the birch fibre provides a smooth surface with good hold out properties.
- Typical properties of Birch hardwood kraft pulp fiber.
- Fiber Length: 1.1-1.5 mm Fiber Width: 16-22 µm Wall Thickness: 3.0-3.6 µm Fiber Coarseness: 114 micro g/m
- Bisulfite Chemi Mechanical Pulp (BCMP)
- A variation of Chemi-Mechanical Pulp (CMP) where chemical used for softening wood chips is bi-sulfite.
- Bisulfite Pulp
- Chemical pulp made using Bisulfite pulping process.
- Bleached Chemo Thermo Mechanical Pulp (BCTMP)
- High yield Bleached CTMP. Non lignin destructive bleaching such as ozone or per oxide bleaching is used to retain yield. Used in newsprint and other printing paper. See CTMP.
- Softwood BCTMP is produced at a similar yield (>85%) to Hardwood BCTMP and the Softwood pulp is produced as a TCF pulp, since only peroxide is used for bleaching to levels between 60-80% ISO Brightness. The key characteristics of Softwood BCTMP are bulk, absorbency, internal bond and stiffness. The pulp is usually co-refined with hardwood and softwood kraft pulp, in varying percentages or sometimes mixed with Deinked (DIP) fiber.
- Softwood BCTMP has been used in a variety of applications. The pulp has been used to prepare fluff pulp (for diapers) up to 80% of the furnish. It has been mixed with DIP furnishes in newsprint and tissue/towel grades to improve bulk and absorbency of the latter. One of the principal applications for Softwood BCTMP is mixed with Hardwood BCTMP in the production of some multiply board grades as a chemical pulp substitute to improve bulk and stiffness. It has also found limited uses in coated and uncoated printing/writing grades and packaging grades but generally its use, in both of these cases, has been superseded by Hardwood BCTMP.
- Hardwoods BCTMP is higher (80-90%), compared to those woods treated by the kraft or Sulfite process (circa 50%), because in the former process most of the wood lignin is retained. Only TCF Hardwood BCTMP is produced, since hydrogen peroxide is the sole bleaching agent. Pulps with an ISO brightness of 88% can be produced, but some brightness reversion will occur due to the presence of lignin. The Lignin levels are lower in hardwoods than in softwoods so the degree of brightness reversion is less. In the pulp mill, by varying the cooking/mechanical pulping conditions, pulps with varying degrees of "Canadian Freeness" can be produced to enhance bulk or pulp strength. In the paper mill hardwood BCTMP pulps are generally used unrefined or with deflaker treatment only. Mill refining can increase the pulp's brightness loss.
- Lower brightness grades (circa 70% ISO) have been used as a part hardwood kraft replacement in tissues and towel, especially for higher bulk in towel. Brighter grades (circa 85% ISO) have been used as a part replacement in a variety of paper grades, including printings and writings (for higher opacity), in multiply boards (for higher bulk, stiffness and improved creasing properties), coated grades (for bulk). In specialties grades, such as decorative laminates, Aspen hardwood BCTMP pulps with the highest brightness have been used to enhance bulk and surface smoothness. A grade of Eucalyptus BCTMP has been used as a part hardwood kraft substitute, to maximize bulk and opacity in grades such as book papers.
- Bleached Eucalyptus Kraft Pulp (BEKP)
- Bleached Kraft Pulp (BKP)
- 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.
- Brown Stock
- The unbleached chemical pulp.
- Chemical Pulp
- Pulp obtained from the chemical cooking or digestion of wood or other plant material.
- Chemi-Groundwood Pulp (CGP)
- Mechanical pulp produced by grinding pre chemical soaked wood log against a stone roll, rotating at very high speed. See Groundwood Pulp..
- Chemi-Mechanical Pulp (CMP)
- Mechanical pulp produced by treating wood chips with chemicals (usually sodium sulfite) before mechanical defibration. Sequence of action: Soaking wood chips in chemical - Refiner.
- Chemi-Refiner Mechanical Pulp (CRMP)
- Same as CMP. Separate name to distinguish from CGP which is also chemi-Mechanical Pulp. Sequence of action: Soaking wood chips in chemical - Refiner.
- Chemo-Thermo-Mechanical Pulp (CTMP)
- Mechanical pulp produced by treating wood chips with chemicals (usually sodium sulfite) and steam before mechanical defibration. Sequence of action: Soaking wood chips in chemical- Steaming-Refiner.
- Cold Soda Pulp
- Agricultural residue or straw pulp produced by soaking these material with dilute caustic solution at atmospheric temperature and pressure. The cost in plant and machinery is minimal. Pulp yield is high. Pulp is normally used for making thick board.
- Combined Deinking
- Deinking process combining flotation and washing.
- Continuous Pulping
- Production of pulp in continuous digester as compared to a batch digester.
- Reacting fibrous raw material with chemical under pressure and temperature to soften and or remove lignin to separate fibers.
- Cotton Pulp
- Pulp made from cotton linter/cotton waste. Cotton linter pulps are available as ECF and TCF grades bleached to 88%+ ISO Brightness. Unrefined these pulps have a very high bulk, air permeance and opacity. On refining there is some development of Schopper Reigler wetness, but little development of strength properties. The opacity increases as refining proceeds due to the sheet closing up as the fibre shortens. The largest change on refining is a loss of air permeance.
- Cotton fiber has a very high alpha cellulose content, which makes this pulp ideal for producing long life archival papers.
- First cut cotton linters find uses in Artists Drawing papers, which must have a resistance to fading, neutrality and stability. These are heavier weight papers were the finish varies from a coarse surface for paint to a smooth surface for graphic work. First cut linters also find uses in some boards (eg. greetings cards) and Mill Run and First cut linters are used as extenders to the much longer Staple Cotton fibers in currency papers.
- Second cut linters are valued for their bulk and purity. In addition to uses in the above grades, Second cut linters are used in Fine and Security to add bulk and prestige value. For Fine papers requiring a good formation, care should be taken when selecting the linter grade to ensure that it is clear of "Fiber Knots". The latter, if present in large numbers in the pulp, can give rise to a poor formation or a "Fish Eye" problem.
- Deinked Pulp (DIP)
- Paper pulp produced by deinking of recovered paper
- The process of removing inks, coatings, sizing, adhesives and/ or impurities from waste paper before recycling the fibers into a new sheet.
- The removal of lignin, the material that binds wood fibers together, during the chemical pulping process.
- Direct Cooking
- Batch cooking in which digester contents are heated by blowing steam directly into the digester.
- Dissolving Pulp
- A high purity special grade pulp made for processing in to cellulose derivatives including rayon and acetate.
- Enzyme Bleaching
- Bleaching technique in which cooked and oxygen-delignified chemical pulp is treated with enzymes prior to final bleaching. Allows pulp to be bleached without chlorine chemicals.
- Esparto Pulp
- Pulp made from esparto grass, grown mainly in Africa. Esparto fibers have thick walls and are short, normally less than 3 mm in length, with an average length of 1.5 mm. The fiber diameter varies from about 0.005 to 0.015 mm, with an average of about 0.012 mm, giving a length to diameter ratio of 125.
- Esparto refines quite quickly yielding low strength properties, but retains bulk, air permeance and excellent opacity. Its low fiber coarseness provides the sheet with a good formation, smoothness and excellent opacity. A particular property of this pulp is its ability to give the sheet a good dimensional stability.
- The formation, smoothness and optical characteristics of this pulp, makes it suitable for all Fine paper grades. Its ability to create a dimensionally stable sheet finds uses in wall paper base. The pulp also has a low extract conductivity which finds application in some electrical grades.
- Typical properties of Esparto pulp fiber.
- Fiber Length: 0.9-1.5 mm Fiber Width: 10 µm Wall Thickness: Fiber Coarseness: 90 micro g/m
- Ethers Pulp
- Generally these are high purity, high viscosity pulps that are swollen in sodium hydroxide initially, followed by reaction with organic epoxides or chlorides like ethylene oxide or methyl chloride to form an organic polymer called cellulose ethers (methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, etc.). Cellulose ethers are used for thickening of fluids such as toothpaste, ketchup, shampoos, diet drinks and hundreds of other applications.
- Eucalyptus Pulp
- Pulp made from eucalyptus. Eucalyptus is a fast growing hardwood, grown mainly in Australia, India etc. Eucalyptus tree takes 5 -8 years for full growth.
- Compared to most other hardwoods, eucalyptus pulps tend to give a higher bulk, tear strength, opacity and formation (due to finer fibers). In all grades of uncoated and coated printing and writings, eucalyptus is used for opacity, formation and smoothness, up to 100% of the furnish in some cases. It can also be used in towel and tissue grades without refining to achieve bulk and air permeance.
- Typical properties of eucalyptus pulp fiber.
- Fiber Length: 0.9-1 mm Fiber Width: 14-16 µ m Wall Thickness: 4-4.5 µ m Fiber Coarseness: 80-90 micro g/m
- Flax Pulp
- Flax is an annual plant, which when fully grown reaches a height of 0.5 to
1.2m (1.5 t0 4 ft). When approaching maturity (after 70 to
100 days depending upon weather conditions), blue (vulgare) or white (album)
flowers are produced depending on the variety. Generally speaking the blue
flowered variety produces fine, good quality fibre whereas the white-flower
plant produces stronger but coarser fibre.
The strands of flax fibre are embedded longitudinally in the stalk of the plant, between the outer epidermis and the central woody tissue. The fibre, which is very high in cellulose, is extracted first by "retting" (rotting either by water or dew) and then by "scutching" the stalks.
Following the process of retting, the straw is dried and then scutched, a process which by mechanical means breaks down the pith, or "boon", and removes it as completely as possible from the fibre.
Pulp made from flax is called Flax Pulp. Flax fiber is soft, lustrous and flexible. It is stronger than cotton fiber but less elastic. Flax pulp is used for the high quality paper such as currency notes and cigarette tissue.
- Flotation Deinking
- Using flotation method for removing ink from paper during the de-inking process.
- Fluff Pulp
- A chemical, mechanical or combination of chemical/mechanical pulp, usually bleached, used as an absorbent medium in disposable diapers, bed pads and hygienic personal products. Also known as "fluffing" or "comminution" pulp
- Fully Bleached Pulp
- Pulp that has been bleached to the highest brightness attainable (> 90 ISO)
- Fully Bleached Kraft Pulp (FBKP)
- A variation of Fully Bleached Kraft
- Groundwood Pulps (GWP) or Stone Groundwood Pulp (SGWP)
- A mechanically prepared (by grinding wood logs against a rough surfaced roll rotating at very high speed) coarse wood pulp used in newsprint and other low cost book grades where it contributes bulk, opacity, and compressibility. Groundwood pulp is economical since all the wood is used; however, it contains impurities that can cause discoloration and weakening of the paper.
- Hard Cooked Pulp
- A pulp intentionally or un-intentionally cooked with less chemical or shorter time or at lower temperature. The net result is less cooked but higher yield pulp. Difficult to bleach.
- Hard Wood (Beech) Sulfite Pulp
- Pulps produced predominately from Beech Wood are characterized by being very easily refined, but develop very little strength. Beech sulfite pulps do however promote smoothness and opacity. This hardwood has a very low lignin content and together with the aggressive nature of the pulping process, pulps of this type are easy to bleach and can produce a high brightness (>93% ISO) and cleanliness.
- Beech sulfite pulps have been used in a variety of Fine papers and Cover papers, usually of the higher grammage range to offset the low pulp strength. Where high brightness and cleanliness pulps have been produced, such grades find applications in photographic, drawing and ink jet papers.
- Typical properties of Hard wood (beech) sulfite pulp fiber.
- Fiber Length: 1.0-1.5 mm Fiber Width: 16-22 µ m Wall Thickness: 2.0-3.6 µ m Fiber Coarseness: 86-114 micro g/m
- Hemp Pulp
- A pulp made from hemp. Hemp fibers are long and thin. Frequently used in the manufacture of cigarette papers but, due to their high opacity and tensile strength, may be suitable for a wide variety of papers which require these specific characteristics.
- Hot Groundwood Pulp or Thermo Groundwood
- Mechanical pulp produced by grinding logs that have been pre-treated with steam.
- Hydrogen Peroxide Bleaching
- A method in which pulp is bleached in an alkaline environment with hydrogen peroxide (H2O2), sometimes using oxygen reinforcement. The method considerably reduces the need for chlorine-containing chemicals in the final bleaching of chemical pulps.
- Jute Pulp
- A pulp made from jute. Jute is a long, soft, shiny fiber that can be spun into coarse, strong threads. It is one of the cheapest natural fibers, and is second only to cotton in amount produced and variety of uses. Jute fibers are composed primarily of the plant materials cellulose, lignin, and pectin. Both the fiber and the plant from which it comes are commonly called jute. The fibers are off-white to brown and 3 to 15 feet (0.9 to 4.5 meters) long. Due to its porosity, this pulp can be used for applications like tea bag and high porosity cigarette papers.
- Kenaf Pulp
- Pulp made from kenaf (an annual plant).
- Knotter Pulp
- Pulp made from the rejects from chemical pulp screening.
- Kraft Pulp
- Chemical wood pulp produced by digesting wood by the sulfate process (q.v.). Originally a strong, unbleached coniferous pulp for packaging papers, kraft pulp has now spread into the realms of bleached pulps from both coniferous and deciduous woods for printing papers.
- A complex constituent of the wood that cement the cellulose fibers together. Lignin is brown in color. Lignin is largely responsible for the strength and rigidity of plants, but its presence in paper is believed to contribute to chemical degradation. To a large extent, lignin can be removed during manufacturing.
- Market Pulp
- Pulp which is made to be used elsewhere for the production of paper. Usually dried to reduce freight costs but may be "wet lap" ( 50% water).
- Mechanical Pulp
- Pulp produced by mechanically grinding logs or wood chips. It is used mainly for newsprint and as an ingredient of base stock for lower grade printing papers.
- Micro Crystalline Cellulose Pulp
- Like Ethers Pulps, these pulps are used in thickening and pharmaceutical applications, particularly in construction of tablets and other non-capsular pills.
- Neutral Sulfite or Mono-sulfite Pulps
- Harwood pulp made by the neutral sulfite process in which the cooking liquor is a single radical sulfite chemical made to produce a neutral pH solution conditions.
- Neutral Sulfite Semi Chemical (NSSC)
- A chemical wood pulping process in which neutral sodium sulfite and sodium carbonate solution is used for cooking. The cooking is carried in slightly alkaline conditions. It is semi-chemical pulping process.
- Nitration Pulps
- High purity pulps that are reacted with nitric acid to form a class of chemical derivatives called cellulose nitrates. Cellulose nitrates are used in applications ranging from solvents to smokeless (gunpowder) propellants.
- Northern Bleached Hardwood Kraft Pulp (NBHKP)
- Northern Bleached Softwood Kraft Pulp (NBSKP)
- Northern Mixed Hardwood Kraft Pulp
- The pulps produced from "Whole Tree Waste" are generally easy to refine, have good opacity and smoothness, but are not particularly strong. The refinability and properties of the pulps produced in a controlled blend, are generally dependent on the dominant species in that blend. For example pulps containing a higher proportion of maple fibre, tend to refine quickly giving a high opacity, smoothness, good formation and watermarking quality, but low strength.
- Pulps from "Whole Tree Waste" have been used as extenders to birch or eucalyptus pulps up to a limited 20% of the furnish. These pulps, and the blended types containing a higher proportion of birch or aspen, have been used in some lightweight papers such as bible paper or directory stock. Where maple fiber is the dominant species (sometimes almost 100% maple), such pulps have been used in coated papers, plastic base surface papers, photographic papers and deep dyed bulky papers.
- Typical properties of Southern Mixed Hard Wood Kraft pulp fiber.
- Fiber Length: 0.9-1.5 mm Fiber Width: 15-25 µ m Wall Thickness: 3.3-3.8 µ m
- Non Wood Pulp
- Chemical or semi-chemical pulp made from Non-wood plant material such as straw, grasses, rag etc.
- Oxygen Bleaching
- A process in which pulp is initially treated with oxygen followed by 4-5 bleaching stages.
- Oxygen Delignification
- A process in which oxygen gas and sodium hydroxide are used to remove lignin from brown stock.
- Ozone (O3)
- A highly reactive gas with molecules made up of three oxygen atoms.
- Ozone Bleaching
- A process that uses ozone to whiten cellulose fibers following the Kraft pulping and oxygen delignification processing.
- Peroxide Bleaching or Hydrogen Peroxide Bleaching
- Method of bleaching pulp with hydrogen peroxide (H2O2) to remove lignin; reduces or avoids the need for chlorine dioxide in final bleaching.
- Pressurized Groundwood Pulp (PGW)
- Mechanical pulp produced by treating logs with steam before defibration against a grindstone under externally applied pressure.
- Characteristics of Groundwood pulp produced under pressure as compared to normal groundwood at 100 CSF
- Pressurized Refiner Mechanical Pulp (PRMP)
- A variation of RMP where extra pressure is created in refiner. See RMP
- A suspension of cellulose fibers in water.
|Initial Wet Strength||60||90||N/m|
|Tear Index||3.5||5.6||mN m2/g|
|Bursting Strength||1.4||2.3||kPa m2/g|
- Radiata Pine Soft Wood Kraft Pulp
- The properties of Radiata Pine pulps is considered to be part way between the characteristics of Northern Softwood and Southern Pine pulp, but generally closer to Northern softwoods.
- Typical properties of Radiata Pine Soft wood pulp fiber.
- Fiber Length: 2.5 mm Fiber Width: 30 µ m Wall Thickness: 3.7-4.0 µ m Fiber Coarseness: 250 micro g/m
- The term “rag” is often used interchangeably with “cotton fiber content” and harkens to a period of time when paper was actually made using cotton rags which were cleaned and then broken down into fibers which were then used to manufacture paper. In a sense it could be stated that the fine paper business has been engaged in recycling materials for production since its very beginning. Today paper is no longer made from rags and the term “rag” is falling in disfavor by the industry in lieu of the phrase “cotton fiber content”.
- Rag Pulp
- Papermaking pulp made from textile waste, cotton, hemp or flax..
- Recycled Fiber
- Fiber obtained from recovered paper; also secondary fiber (cf. virgin fiber).
- Recycled Fiber Pulp
- Pulp produced from recovered paper to be used in papermaking.
- Refiner Mechanical Pulp (RMP)
- Mechanical pulp produced by passing wood chips between the plates of a refiner without any pre-treatment. Defibration takes place under atmospheric pressure. The wood chips are defibrated at about 1000C mostly in 2 stages with consistencies of 20-30% in the second stage.
|Burst Index||mN m2/g||1.4||1.9||2.3|
|Tear Index||kPa m2/g||4.1||7.5||9.0|
|R-48 Bauer McNett||28||50||55|
- Refiner Sawdust Pulp
- Mechanical pulp produced from sawmill dust.
- Reinforcement Pulp
- Softwood chemical pulp added to give paper greater strength and to improve runnability on the paper machine or printing press.
- Sawdust Pulp
- Pulp made from saw mill dust. Catalyst Paper Canada make sawdust pulp (Plant closed).
- Scandinavian Softwood Kraft Pulp
- The pulpwood is largely Scots pine containing 20-25% summerwood (latewood), depending on the north to south wood location. Bleached pulps from this area have a good burst and tear strength, but are the least bulky of the softwood kraft pulps. These pulps can be used interchangeably in most printing and writing grades. Pulps produced from wood grown mainly in the north of Scaninavia tend to have a higher, thinner walled, springwood content. Such pulps are useful for lighter wight papers. Pulps produced from wood grown mainly in the south of the region, tend to be more absorbent and bulky (due to a higher, thicker walled, summerwood content) and these pulps find uses in grades such as coffee filters.
- Typical properties of Scandinavian Soft Wood Kraft pulp fiber.
- Fiber Length: 3.0-3.7 mm Fiber Width: 27-38 µ m Wall Thickness: 2.9-3.0 µ m Fiber Coarseness: 160-200 micro g/m
- Semi-Alkaline Pulp
- A variance of semi-chemical pulp where cooking liquor is alkaline (NaOH or NaOH+Na2S)
- Semi-Bleached Pulp (SBP)
- Pulp bleached to a brightness somewhere between that of unbleached and fully bleached pulp.
- Semi-chemical Pulp
- Pulp produced by chemical treatment followed by mechanical treatment.
- Semi-chemical Mechanical Pulp (SCMP)
- Same as Semi-chemical Pulp.
- Soda Pulping
- An alkaline pulping process that uses a simple, sulphur- free sodium hydroxide as cooking liquor.
- Sisal Pulp
- The main characteristic of sisal pulp is its high porosity, making it an excellent raw material for papers such as dielectric, plug wrap, laminating substrate, vacuum bag, tea bag, filtration papers and wet laid non-wovens
- Soft Cooked Pulp
- A pulp intentionally or un-intentionally cooked with more chemical or longer time or at higher temperature. The net result is over cooked but lower yield pulp. Easy to bleach.
- Soft Wood Sulfite Pulp
- Softwood Sulfite pulps requires less refining to reach a given freeness (° SR). They are characterized by having a high initial wet strength at low refining values, but have a low bulk, tear, opacity and absorbency at the same tensile level compared with Softwood kraft pulps. Softwood Sulfite pulps can provide a good surface and formation. Pulps produced in Western Canada tend to be stronger than those produced in Scandinavia/Europe.
- Softwood Sulfite pulps are used in printing and writing papers, both uncoated and coated and in high grade card stock. In colored papers the use of Softwood sulfite fibers at a high level of the furnish promotes even dyeing. These pulps have a particular application in tissue grades, since the pulp can develop adequate tensile strength very quickly, has a low adhesion to MG dryers and can provide softness to the tissue grade. When heavily refined, sulfite pulps produce a very dense paper and this property finds uses in such products as greaseproof and tracing papers. The easy bleaching nature of sulfite pulps can enable the pulp supplier, in a few cases, to produce a grade with a very high brightness (circa 93/94% ISO) for use in photographic grades or papers suitable for Artists use.
- Typical properties of Soft wood sulfite pulp fiber.
- Fiber Length: 3.0-3.7 mm Fiber Width: 27-38 µ m Wall Thickness: 2.9-3.5µ m Fiber Coarseness: 160-200 micro g/m
- Southern Bleached Hardwood Kraft Pulp (SBHKP)
- Southern Bleached Softwood Kraft Pulp (SBSKP)
- Southern Mixed Hardwood Kraft Pulp
- Southern mixed hardwoods refine at a similar rate to bleached eucalyptus globulus pulps. These pulps tend to retain a higher tear strength, bulk, stiffness and porosity, but are generally weak in tensile and have a lower opacity. Their high coarseness value detracts from the paper's formation and if the pulp should contain a high percentage of white oak fiber, this can give rise to vessel picking problems.
- Southern mixed hardwoods are generally used at up to 50% of a papermaking furnish with single species softwoods. Southern mixed hardwoods has been used in high volume paper qualities, including printings and writings, packaging grades and uncoated art papers (for stiffness and bulk). The pulp also finds use in towel grades were it contributes to bulk and absorbency.
- Typical properties of Southern Mixed Hard Wood Kraft pulp fiber.
- Fiber Length: 1.4-1.8 mm Fiber Width: 18-32 µ m Wall Thickness: 5.0 µ m Fiber Coarseness: 130-200 micro g/m
- Southern Pine Soft Wood Kraft Pulp
- Southern Pine pulps have thick fiber walls, due to a high summer wood content. These pulps are characterized by having a high tear strength, bulk and absorbency, but require much more refining to develop a useful tensile strength, compared to Scandinavian softwood krafts. The opacity of Southern Pine pulps is less than other softwoods and their high coarseness can lead to formation difficulties.
- Pulps produced from single species in the more northern part of the Southern Pine region or those produced from juvenile wood, can be part interchanged with Northern softwoods in a range of both coated and uncoated, Fine Printing and Writing grades.
- The high absorbency of Southern Pine pulps find applications in tissue, towel and filter (EG Coffee Filters) grades. These pulps are also used in packaging grades and circuit boards. Their resistance to refining and high tear, due to the long fiber and thick fiber wall, finds some application in Tracing Paper.
- Typical properties of Southern Pine Soft Wood Kraft pulp fiber.
- Fiber Length: 3.8-4.4 mm Fiber Width: 36-40 µ m Wall Thickness: 5.0-10 µ m Fiber Coarseness: 230-300 micro g/m
- Specialty Pulp
- Chemical pulps used for purposes other than ordinary papermaking (e.g. in textile production)
- Straw Pulp
- Pulp that is made from the straw of grains such as rice straw. It is cooked by soda process.
- Sulfate Pulping
- Alkaline process of cooking pulp.
- Sulfite Pulping
- Acid process of cooking pulp
- Tandem Thermo Mechanical Pulp (Tandem TMP)
- Sequence of actions: Chips - steaming - 2- refining stages. Used to pulp HW and SW. High yield pulp.
- Thermo Chemi-Mechanical Pulp (TCMP)
- Sequence of actions: Chips - steaming - soak in chemical- refiner. Used to pulp HW and SW. High yield pulp. The steaming is done at 140-1550C for short time at 300-500 kPa or 3-5 bar.
- Thermo Mechanical Pulp (TMP)
- Sequence of actions: Chips - steaming - refiner. Used to pulp HW and SW. High yield pulp. Pulp used for newsprint etc.
- Thermo Pulp
- Thermopulp differ from TMP in that the first-stage pulp is heated up to very high temperature (~1700C) before entering the 2nd stage.
- Totally Chlorine Free (TCF)
- Totally chlorine free applies to virgin fiber papers that are unbleached or processed with a sequence that includes no chlorine or chlorine derivatives. (Also see ECF)
- Un-washed Pulp
- Semi-chemical or Chemical pulp before washing. A stage in pulping process where pulp is cooked and transfer to storage tank but spent and residual cooking liquor is not separated from fibers.
- Virgin Fiber
- Fiber that has never been used before in the manufacture of paper or other products.
- Viscose Pulp or Rayon Grade Pulp
- Viscose pulps are high purity pulps that are mixed with sodium hydroxide to form a material called alkali cellulose and then reacted in a mixture of sodium hydroxide and carbon disulfide. This resulting substance, called cellulose xanthate is further reacted with a mineral acid to regenerate pure cellulose. The regenerated cellulose can be a fiber, like rayon, or other forms, like the film cellophane.
- Washed Pulp
- Semi-chemical or Chemical pulp after washing (removing residual cooking and spent liquor).
- Washing Deinking
- Deinking in which solid particles are separated on the basis of their size by washing. Also see Flotation Deinking and Combination Deinking.
- Wood-Free Pulp
- Pulp furnish without mechanical pulp.
- Wood Pulp
- Mechanical or chemical pulp made from wood (cf. Non-wood pulp).