CPC Definition - Subclass D21C
This place covers:
- Pretreatment of the finely-divided materials before digesting, e.g. with water, acid reacting compounds, alkaline reacting compounds or oxygen-generating compounds or physical methods for facilitating impregnation.
- Pulping cellulose-containing materials, e.g. sulfate processes, or other features of pulping processes.
- Other processes for obtaining cellulose, e.g. cooking cotton linters; working-up other than mechanical of waste-paper.
- Digesters.
- After-treatment of cellulose pulp, e.g. of wood pulp or cotton linters, e.g. washing, removal of fats, resins, pitch or waxes, bleaching or de-watering other than in general.
- Regeneration of pulp liquors, e.g. treatment of pulp gases, recovery of the heat content of the gases, deodorisation, concentrating spent liquor by evaporation other than evaporating and distillation or combustion of pulp liquors.
Subclass D21B covers fibrous raw material or their mechanical treatment.
Subclass D21D covers treatment of the materials before passing to the paper-making machine.
Subclass D21F covers paper-making machines and methods of producing paper thereon.
Subclass D21H covers pulp compositions.
Subclass C08B covers polysaccharides and derivatives thereof.
This place does not cover:
Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:
Attention is drawn to the following places, which may be of interest for search:
Cellulose as gelling or thickening agents in food | |
Filtration material of cellulose | |
Semi-permeable membrane of cellulose | |
Moulding material of cellulose | |
Treatment of water, waste water, sewage or sludge to be treated from the paper or cellulose industry | |
Use of cellulosic materials as fillers for mortars, concrete or artificial stone | |
Compositions of mortars, concrete or artificial stone, containing only organic binders, e.g. cellulosic waste liquor | |
Peptides immobilised on cellulose | |
Lignin; Modified lignin; High-molecular-weight products derived therefrom | |
Macromolecular compounds derived from lignocellulosic materials | |
Compositions of cellulose, modified cellulose or cellulose derivatives | |
Coating compositions based on cellulose | |
Obtaining, purification or chemical modification of natural resins | |
Destructive distillation of cellulose-containing material | |
Production of fats or fatty oils | |
Processes using or culture media containing cellulose or hydrolysates thereof | |
Processes using or culture media containing waste sulfite liquor | |
Ethanol produced as by-product or from waste or cellulosic material substrate | |
Glucose by saccharification of cellulosic material | |
Obtain filaments or fibers for spinning | |
Monocomponent artificial filaments of cellulose or cellulose derivatives |
The invention per se should be classified in the last appropriate place. Ideally, one group should be given for covering the main aspect of the invention per se. Exceptionally, the core of the invention may also be classified by using several groups (up to three).
In this place, the following terms or expressions are used with the meaning indicated:
bagasse | fibre remaining after the extraction of the sugar-bearing juice from sugarcane |
bleaching | treatment of lignocellulosic material to obtain a pulp/paper having an increased brightness |
cellulose | structural component of the primary cell wall of green plants. It is an organic compound with the formula (C6H10O5)n and is the major constituent of paper, paper-board and of textiles made from cotton, linen and other plant fibres. |
cotton linters | fine, silky fibres which adhere to the seeds of the cotton plant after ginning and are traditionally used in the manufacture of paper and as a raw material in the manufacture of cellulose |
delignification | treatment of lignocellulosic material to remove a part of the lignin |
lignocellulosic material | cellulosic material which also comprises lignin |
linings | material that covers the inner surface of something |
pulp | a dispersion (e.g. aqueous suspension) comprising cellulosic fibres and optional additives; it is prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops or waste paper |
In patent documents, the following words/expressions are often used with the meaning indicated:
fibres | fibers |
This place covers:
Different pre-treatments (e.g. impregnation) of finely divided cellulosic containing material using e.g. water, steam, acids, alkaline compounds, oxygen generating compounds or physical methods for facilitating impregnation.
Attention is drawn to the following places, which may be of interest for search:
Pre-treatment of the raw material by physical or chemical means |
This place covers:
Pulping with inorganic bases or alkaline reacting compounds, e.g. the sulphate process
Pulping with acid, acid salts or acid anhydrides
Pulping with sulphur dioxide, sulphurous acid, bisulphites or sulphites
Pulping with nitrogen oxides, nitric acid, nitrates or nitrites
Pulping with organic solvents or in solvent environment
Other features of the pulping process
This place does not cover:
Digesters |
This place covers:
Other processes for obtaining cellulose such as:
- cooking cotton linters
- processes characterised by the choice of cellulose-containing starting material
- treatment of cellulose-containing material with microorganisms or enzymes
- working-up waste paper
- working-up waste paper, e.g.de-inking
This place does not cover:
Mechanical part of working up waste paper |
Attention is drawn to the following places, which may be of interest for search:
Enzymes (generally) | |
De-inking of waste paper using flotation | |
Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse | |
Pulp from secondary fibres | |
Microorganisms or enzymes added to the pulp or as a paper impregnating material |
This place covers:
This group refers to structural features of the digester, i.e. defining different types or parts of the digester, e.g. rotary digesters, linings, feeding devices, discharge devices, heating devices, devices for regulating or controlling, means for circulating the lye (e.g. white or black liquor) or safety devices.
Attention is drawn to the following places, which may be of interest for search:
Continuous (pulping) processes | |
Multistage (pulping) processes | |
Processes or apparatuses for adding material to the pulp or paper; controlling or regulating not limited to any particular process or apparatus |
This place covers:
Modification of pulp properties
Washing
Displacing cooking or pulp-treating liquors contained in the pulps by fluids, e.g. wash water or other pulp treating agents
Removal of fats, resin pitch or waxes
Chemical or physical purification i.e. refining of crude cellulose by removing non-cellulose contaminants, optionally in combination with bleaching
Bleaching, e.g with halogen or halogen containing compounds, with ClO2 or chlorites, with oxygen or its allotropic modifications, with ozone, with per compounds such as peroxides or peracids
Apparatus for bleaching
De-watering
Elimination of cooking or pulp-treating liquors from the pulp
Attention is drawn to the following places, which may be of interest for search:
Hemicellulose | |
Natural resins | |
Purification by mechanical means | |
Modification of the pulp properties by a particular after treatment | |
Agents for preventing deposition on paper mill equipment, e.g. pitch or slime control | |
De-watering in general |
This place covers:
Aspects concerning the production and the treatment of green and white liquors, e.g. causticizing green liquor
Combustion of pulp liquors
Concentration spent liquors by evaporation
Deodorisation or elimination of malodorous compounds, e.g. sulphur compounds such as hydrogen sulphide and mercaptans, for gas streams
Introduction of auxiliary substances into the regenerating system in order to improve the performance of certain steps of the latter, the presence of these substances being confined to the regeneration cycle
Recovery of by-products, i.e. compounds other than those necessary for pulping
Regeneration of alkali lye, of pulp liquors or effluent waste waters, of acid, neutral or alkaline sulphite lye
Treatment of pulp gases or of gases arising from various sources in pulp and paper mills
Recovery of the heat content in the gases
Regeneration of gaseous SO2, e.g. arising from liquors containing sulphur compounds
Wet combustion
Treatment of pulp liquor without previous evaporation, by oxidation of liquors remaining at least partially in the liquid phase, e.g. by application of pressure
This place does not cover:
Water treatment |
Attention is drawn to the following places, which may be of interest for search:
Evaporation in general | |
Hemicellulose | |
Macromolecular compounds derived from lignin | |
Macromolecular compounds derived from lignocellulosic material | |
Production of biofuel, i.e. ethanol |