PAPER GLOSSARY

S - Z

S

Sack paper
See "Kraft paper"
Safety paper
Papers with a special protection against abusive imitation. The safeguards used during the production of the paper - some of them chemical - are secret
Sanitary papers
The group of sanitary papers includes cellulose wadding, tissue and crepe paper, made from waste paper and/or chemical pulp - also with admixtures of mechanical pulp. As a consequence of the importance of tissue today, this name is now used internationally as a collective term for sanitary papers. These grades are used to make toilet paper and numerous other sanitary products such as handkerchiefs, kitchen wipes, towels and cosmetic tissues
Sanitary tissue paper
Tissue is a sanitary paper made from chemical or waste paper pulp, sometimes with the admixture of mechanical pulp. It has a closed structure and is only slightly creped. It is so thin that it is hardly used in a single layer. Depending on the requirements the number of layers is multiplied. Creping is made at a dryness content of more than 90 %. The dry creping (unlike with sanitary crepe papers) and the low grammage of a single tissue layer result in a high softness of the tissue products. For consumer products it is normally combined in two or more layers. The flexible and highly absorbent product [is mainly produced from chemical pulp and/or DIP - sometimes also with admixture of groundwood pulp] can also be provided with wet strength. Applications: facial tissues, paper handkerchiefs, napkins, kitchen rolls, paper towels, toilet paper
SC
See Supercalendered
SC paper
SC stands for supercalendered. This is a calendered, uncoated mechanical paper with fillers
Secondary fibre
See Recycled fibre
Security paper
Woodfree, sometimes rag-containing but always high quality paper with a genuine multistage watermark to avoid falsification
Semi-alkaline pulp (SAP)
Sulphite pulp cooked at slightly alkaline pH (normal sulphite pulp is cooked at acid pH). SAP is superior in strength to normal sulphite pulp. Used mainly in printing papers
Semi-bleached
Pulp bleached to a brightness somewhere between that of unbleached and fully bleached pulp
Semi-chemical pulp
High yield pulp in which the fibres have been separated mechanically after a preliminary chemical treatment; e.g. NSSC pulp
Settleable solids
Suspended solids that will settle out of an effluent during mechanical treatment
Sheeter
Machine for cutting the paper web into sheets
Short fibre
Applies to paper or pulp containing a high proportion of short wood fibres
Sized paper
Sizing reduces the water absorbency of the paper and thus creates the condition for the writability with ink. Sized paper is also used for many other purposes (printing, coating, gluing, etc.), and the sizing agents must fulfil a wide range of tasks. For instance, they control the water absorbency and increase the ability to retain water and ink (pick resistance)
Sizing
Treatment of either stock or paper surface with size to improve strength and reduce absorbency of water
Sludge handling
Compaction and dewatering of sludge separated from treated effluent
Softboard
Softboards are soft, bulky boards with a felt-like character. They are used for protective covers, roofing papers, beer mat boards, packaging boards and flongs
Solid fibre board
Collective term for all solid board grades
Special pulps
Chemical pulps used for purposes other than ordinary papermaking (e.g. in textile production)
Speciality paper
The group of speciality papers comprises numerous paper grades, each characterised by particular properties. These properties often require special raw materials
Spent liquor
Waste liquids from pulping and washing (cf. black liquor)
Steam calendering
See steam finishing
Steam finishing
A way of treating paper before calendering to improve its density and surface smoothness
Steaming
Wood chips are often treated with steam prior to pulping; used in thermomechanical pulping
Stock
Suspension in water (slurry) of fibres and other components for papermaking during the period between defibration and web formation
Strength
Ability of paper or board to withstand mechanical stress
Suitcase board
Sized, high-density and strong board which generally is water repellent on both sides as a result of surface finishing. It may be pressed, folded, moulded, bent, riveted and sowed. Thickness 1 - 3 mm
Sulphate pulp
Chemical pulp produced by cooking wood in a liquor containing sodium hydroxide and sodium sulphide
Sulphite pulp
Chemical pulp produced by cooking wood in a liquor containing sodium, magnesium, ammonium or calcium bisulphite
Supercalendered (SC)
Paper treated in a supercalender, usually separate from the paper machine; uncoated magazine paper
Supercalendering
Treatment of paper on an off-machine supercalender to improve smoothness and gloss
Surface treatment
Treating the surface of paper or board with size or coating colour
Surface-sized paper
Paper that has been sized on the surface, generally using a size press inside the paper machine
Suspended solids
Bark, fibre and other wood-based material released into water during debarking and pulping; filler and coating colour residues from paper mills; solid impurities formed during waste water treatment. Solids can be removed from waste water by settling or filtration
Synthetic fibre paper
Papers made from synthetic fibres such as polyamide and polyester, from viscose staple fibre or sometimes also with fillers. The fibres are mainly held together by binders. The durable synthetic fibre papers are used for maps and highly important documents such as driving licences or vehicle registration books

T

Talc
Mineral used in papermaking as a filler and coating pigment
Tearing resistance
Force needed to tear a sheet of paper under specified conditions
Testliner
Mainly produced from waste paper used as even facing for corrugated board or as liner of solid board. They are often produced as duplex (two-layer) paper. The grammage is higher than 125 gsm
Thermal papers
One-side coated thermoreactive papers used for printing text and illustrations on telefax machines, thermoplotters (e.g. for technical drawings) and thermoprinters (e.g. for labels, tickets, sales slips and other vouchers)
Three-layer paperboard
Paperboard consisting of three layers: front liner made from chemical pulp and/or waste paper pulp, middle made from waste paper pulp and back made from mechanical and/or chemical and/or waste paper pulp
Tissue paper
Collective term for papers of a grammage of less than 30 gsm that differ in applica-tion and composition but have the common feature of being thin. They are mainly used to wrap delicate items, as tissue for bottle wrapping, as fruit tissue wrappers for oranges or as wet strength flower tissue. They are also used as base paper for the carbon paper production, as lining tissue for envelopes and as lining paper (e.g. as a composite with aluminium foil in cigarette packaging). The extremely thin Japanese tissue papers are sometimes produced in grammages as small as 6 to 8g
Toilet papers
See "Sanitary tissue papers" and "Sanitary crepe papers"
Totally chlorine-free (TCF)
Pulp bleached entirely without chlorine chemicals
Totally Chlorine-free paper (TCF)
Abbreviated used for papers made from pulps that were not bleached with chlorine compounds. The paper itself is not bleached
Transparent paper
Extended and particularly careful grinding of high quality fibres (hard chemical pulps, rags) yields a raw material permitting the production of transparent paper
Trimmings
Paper or board left over from web or sheet cutting operations
Twin-wire machine
Paper or board machine in which the web is formed and partially dewatered between two wires
Typewriter paper
Typewriterpaper (bank paper) is often woodfree, usually sized, erasure resistant and in rare cases coloured. It can be both with and without watermark and can also be embossed. Typewriterpaper (bank paper) is often woodfree, usually sized, erasure resistant and in rare cases coloured. It can be both with and without watermark and can also be embossed

U

Unglazed (UG)
Uncalendered paper

V

Vegetable parchment
Vegetable parchment, often also called parchment paper, is a highly pure packaging material that is impermeable for grease and has a particularly high dry and wet strength. It is made from an absorbing, pure, bleached chemical pulp in a special process using concentrated sulphuric acid
Veining
Uneven colouring of pulp
Virgin fibre
Wood fibre never before used to make pulp, paper or board. Also primary fibre (cf. secondary fibre)
Viscose pulp
Dissolving pulp intended for the manufacture of viscose

W

Wall base paper
Collective term for papers that are suitable for wallpaper production. These papers may be monolayer or multilayer (simplex/duplex), woodfree or mechanical, uncoated or coated, and can also be laminated, pre-pasted or peelable
Washer room
Pulp mill department where pulp is washed free of cooking chemicals
Washing deinking
Deinking in which solid particles are separated on the basis of their size by washing
Waste paper
Paper after it has been used. Most can be recycled into new paper products. Known also as recovered paper and secondary fibre
Watercolour paper
Woodfree (See "Woodfree paper") drawing paper with a rough or structured surface, sometimes also rag-containing or pure rag paper. Sizing is adapted to ensure that the water colours are well accepted by the paper but do not strike through. The paper must be erasure resistant. If they are hand-made, water colour papers have the additional advantage that they expand evenly in all directions when they are moistened
Watermark
A localised modification of the formation and opacity of the sheet, so that a pattern or design can be seen
Waxed paper
Nearly woodfree papers that are impregnated with paraffin, wax or wax/paraffin/plastic mixtures. With the appropriate saturation agent and process the product may be tailored for specific applications, e.g. packaging of bread or sweets or wrapping razor blades
Waxing
Coating or impregnating of paper or board with paraffin or wax
Web
Continuous sheet of paper formed on the paper machine wire
Web glazing
Imparting a gloss to the paper web; calendering
Wet end
First part of the paper machine up to the drying section
Wet strength
Mechanical strength of paper when wet, measured under specific conditions
Wet strength and alkali resistant paper
Adding alkali resistant wet strength agents to the fibre suspension yields papers that have a remarkable strength even when wet
Wet tensile strength
Ability of wet paper to resist tension in the plane of its surface
White water system
Flow circuit for paper machine white water (includes pipes, storage tanks, cleaning equipment, water from forming section and return feed)
Winder
Machine for cutting the paper web longitudinally into narrower webs, which are then wound to reels; also slitter-winder
Winding
Operation whereby a web of paper or board is wound into one or more reels
Wire
Flat belt of metal or plastic mesh on which the paper or board web is dewatered
Wood containing
Paper containing a certain proportion of mechanical pulp
Wood pulp
Mechanical or chemical pulp made from wood (cf. Non-wood pulp)
Woodfree
Paper made using the chemical rather than the mechanical pulping process
Woodfree paper
Paper consisting of chemical pulp fibres. It does not contain any mechanical pulp beyond a permissible content of 5 % by mass
Writing paper
Uncoated paper that is suitable for writing with ink on both sides. The writing must neither bleed nor strike through. Writing paper is always fully sized (See "Sized paper") and also suitable for printing. It can be woodfree or mechanical, depending on the intended purpose. The admixture of fillers makes it less translucent

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