Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
  • D21F11/002—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines by using a foamed suspension
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
  • D21B1/06—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by dry methods
  • D21B1/063—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by dry methods using grinding devices
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
  • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/03—Non-macromolecular organic compounds
  • D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
  • D21H17/07—Nitrogen-containing compounds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/63—Inorganic compounds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
  • D21H25/04—Physical treatment, e.g. heating, irradiating
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
  • D21J1/00—Fibreboard
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
  • D21J7/00—Manufacture of hollow articles from fibre suspensions or papier-mâché by deposition of fibres in or on a wire-net mould

Definitions

• the invention relates to a process for producing a self-adhesive porous, pressure-resistant molded body based on comminuted, lignocellulose-containing fibers.
• starting materials are both hardwood and softwood, thinnings and other lignocelluloses such as hemp, flax, straw, palm trees, bamboo, bagasse and grass.
• the proportion of lignocelluloses is up to 100 percent.
• the moldings can be used in particular in the construction industry, in furniture production, in the packaging industry, for sound insulation, for thermal insulation and also in humid environments.
• WO 02/055722 A1 is a process for the preparation of solid products from vegetable raw materials, so-called starch-bound lightweight wood-based panels described.
• Wood or straw meal with a particle diameter of less than 0.5 mm is mixed with starch, in particular from corn but also from cereals or rice, suitable microorganisms, in particular yeasts or bacteria and water.
• the dough thus obtained is subjected to a fermentation process under controlled temperature, pressure and moisture conditions and at least partially dried.
• additives can be mixed in with the dough, for example to improve the mechanical properties or to resist biodegradation.
• the mass is pressed into molds and baked to a kind of "wood bread".
• the wood content of these biogenic light products is a maximum of 78%.
• the dried material has densities of 230 kg / m3 to 310 kg / m3, the bending strength is between 0.9 N / mm 2 and 1.5 N / mm 2 ; the thermal conductivity is approx. 0.08 W / mK.
• a process for the production of wood-based insulation panels with gross densities of 60 kg / m 3 to 80 kg / m 3 was developed in the 1940s at Kramfors AB, a Swedish sulphite pulp mill ( SE 112 134 . SE 116 103 . SE 117 003 ).
• the process is also referred to as the Orrmell-Rosenlund or Kramfors process, according to the leading developers Aron and Orrmell.
• the production took place in the 1940s and 1950s, each in a factory in Sweden, Finland and the USA. However, these so-called. Kramforsplatten could not compete, production was stopped in 1951.
• the starting material for the production of these products were chemically treated wood components, which were formed during the sulfite process for the production of wood pulp as by-products. This was in particular largely unresolved branch material, which was first ground and then added with binders and foam-forming substances; however, the exact additions are not documented. It is known, however, that large amounts (30: 1 to 4: 1) of ligninsulfonklar leachings were added and these served as a binder and they could turn on the other to a fine-pored foam. This process is highly pH-dependent, so pH control played an important role throughout the manufacturing process, with higher pH resulting in a higher foam volume.
• a process for producing a foamed cellulosic filler by wet foaming will be described.
• Cellulosic material such as pulp, pulp or waste paper is used as starting material. This is added with a mass fraction of 0.1% to 20% of water-soluble adhesive, 0.5% to 20% by weight of a chemical blowing agent and 10% to 30% by weight of water.
• the mixture obtained is first preheated to 30 ° C to 90 ° C, then placed in molds and then heated to 70 ° C to 150 ° C for foaming and drying. A volume increase of up to 500% of the original volume of the cellulosic material is achieved.
• azodicarbonamide ADCA
• ABFA azobisformamide
• AIBN azobisisobutyronitrile
• N N'-dinitrosopentamethylantatramin
• DPT p-toluenesulfonylhydrazide
• OBSH p, p'-oxybis (denzolsulfonyl) hydrazide
• inorganic foaming agents ammonium carbonate and sodium bicarbonate used alone or as a mixture.
• the material is particularly suitable as a heat-insulating filler material and as a packaging material.
• a process for producing viscose foam is in US-A-2 077 412 described.
• Cellulose xanthate is mixed with water and stirred for several hours.
• ammonium chloride solution and substances which promote foaming are added and the mixture is whipped until foamy.
• the frothy mass thus obtained is finally solidified by treatment with gaseous sulphurous acid.
• Suitable substances which promote foaming are fatty acids, especially oleic acid, albumin, soap, saponins, dextrins or rubbers.
• the material is suitable for heat and sound insulation, as packaging material and as filter material.
• Process for producing paper foam are in DE 40 08 862 C1 and DE 34 20 195 C2 described. It is a mixture of paper fibers and plasticizable starch ( DE 40 08 862 C1 ) or of paper fibers, plasticisable starch and polyvinyl alcohol ( DE 34 20 195 C2 ) compacted and plasticized with the aid of an extruder and expanded upon exiting the extruder by temperature and pressure drop and thereby foamed.
• This paper foam is used in particular as packaging material in the form of flips.
• Softwood was used as raw material for the grinding wood production and thus for the TRONAL plate; Hardwood was not used because no fibers, but only a flour-like substance, which exerts no sticking and verkittende effect arises.
• the stock preparation took place in two steps: first the material was pre-ground in beaters with basalt garnish or in defibrators to an SR value of 20 to 22, then these fibers were finished with basalt garnish in Dutch, to achieve the desired SR value - typically between 55 and 80.
• the processed fibers were suspended in water and filled in casting machines. In mold boxes with sieve bottom, the excess water was squeezed out and obtained a fiber cake with a solids content of about 20%. This was in floor warm air dryers at max.
• Lightweight materials can be found in the most diverse areas, for example in construction, in vehicle technology and in packaging. In addition to the weight savings, the heat and sound insulating properties that result from the high porosity of the materials are often in the foreground.
• the majority of the light materials produced are foams produced from petrochemical raw materials. A far smaller proportion is made from renewable raw materials; These include, among others, highly porous mats, nonwovens and natural fiber fabrics. Products of this kind can be found as thermal insulation in construction as well as in vehicles for sound absorption. Nonwovens and scrims made of natural fiber materials have the disadvantage of being less pressure-resistant. Furthermore, unlike synthetic foams, it is not possible to produce closed-pore structures.
• the object of the present invention is to provide a method which does not show these disadvantages and also allows the production of a cheap, porous, pressure-resistant material from renewable raw materials without chemical treatment and subsequent separation of substances or a chemically induced depolymerization of the raw materials.
• the moldings should consist entirely or at least predominantly of vegetable substances.
• a targeted adjustment of the density over the manufacturing process should be possible through the process, a targeted adjustment of the density over the manufacturing process
• the materials should be easily recyclable and correspond to the emission potential of a comparable amount of wood when burned.
• the raw materials are all types of lignocelluloses. According to the method of the invention, all types of wood, including bark or root material, sawmill by-products and thinning wood, but also waste wood, various annual plants without chemical pretreatment, but also modified lignocellulose-containing raw materials are suitable. Surprisingly, it has been shown that hardwoods, in particular, represent extremely suitable raw materials.
• the inventive method for producing a porous molded article provides that pre-shredded, lignocellulose-containing fibers are processed at temperatures between 120 ° C and 180 ° C and at a pressure of 2 to 8 bar, optionally together with water, to a fiber suspension, in particular disintegrated and that it is then filled into a mold without the addition of a synthetic binder or applied to a support and dried.
• a porous structure is obtained, so an open-pored and permeable structure, which can be a lightweight construction with high damping and insulation properties realize.
• the temperature can be increased during the milling stepwise, ie at intervals, the temperature increase can be carried out in evenly spaced steps.
• a development of the invention provides that up to 70% of the total disintegration takes place at the target temperature, so that the disintegration is carried out at the intended maximum temperature in order to release the binding materials contained in the lignocellulose-containing fibers.
• thermomechanical process preferably in an atmospheric refiner without overpressure and at room temperature to a desired fiber length between 200 to 800 microns occur.
• the setting of the fiber length obtained is carried out by the use of different Mahlusionngeometrien by adjusting the Mahlplattenabstandes and the setting of Mahlzykleniere, which can be between 1 and 10.
• different suspensions are mixed or a fiber suspension is produced with batches of fibers of different fiber length, which is then poured into a mold or applied to a carrier.
• a highly viscous suspension having a solids to water ratio of from 1: 2 to 1:20, preferably from 1: 5 to 1:10 is prepared from the aqueous fiber suspension prior to introduction into the mold or application to a support becomes.
• Dewatering can be done by decanters or other mechanical drainage to reduce thermal energy during drying.
• a screen belt, a non-woven belt or a conveyor belt can be used to enable a continuous production.
• the bands may be laterally limited and permeable to water to allow for mechanical pre-drainage.
• a shape a three-dimensionally formed, one-piece or multi-part mold with closed or perforated walls can be used to allow more complex shapes.
• the mold is preferably provided with a non-stick coating, such as PTFE, or is made of a non-adhesive material to facilitate demolding.
• the highly viscous suspension can be introduced under pressure into the mold to achieve a uniform filling of the mold and a variation of the density of the filling and of the finished product.
• the highly viscous suspension can be pre-dewatered prior to the thermal drying by means of vacuum or by mechanical pressure in order to reduce the thermal energy expenditure.
• the thermal drying is carried out by a convective and / or conductive heat flow and / or by heat radiation and / or by electromagnetic radiation, wherein the drying is preferably carried out in a dryer at temperatures of initially between 110 ° C and 140 ° C.
• the suspension introduced into the mold or applied to the support is preferably dried at high temperatures for between 0.5 and 2 hours in order to activate the autoadhesive bonds, then the drying temperature is lowered to below 80 ° C., preferably to 70 ° C., in order to reduce the drying temperature remove residual moisture.
• the residual drying time is particularly dependent on the type of drying and can be in a drying oven between 5 and 12 hours and at a drying with electromagnetic radiation between 10 and 30 min.
• blowing agents in particular gas generators (CO 2 releasing agents), N 2 O, propane, n-butane or pentane or completely decomposing blowing agents, in particular hydrogen peroxide, can be added to the highly viscous suspension before introduction into the mold or application to a carrier , Additionally or alternatively, gases for foam formation can be introduced into the highly viscous suspension before introduction into the mold or application to a support by mechanical, pneumatic and / or thermal processes.
• CO 2 releasing agents CO 2 releasing agents
• N 2 O propane, n-butane or pentane
• completely decomposing blowing agents in particular hydrogen peroxide
• a further development of the invention provides that process additives, product-improving additives or additives for adjusting desired product properties are added after or during the preparation of the highly viscous suspension, for example hydrogen peroxide alone for adjusting the porosity.
• wood ingredients such as lignin, hemicellulose and cellulose can be chemically modified to react with each other to form a bond between the fibers. This bond is water-resistant and thus the foam does not disintegrate in the water, whereby a stable, foamed suspension can be produced, which remains stable even in the mold and on the support during the drying process, so that a pressure-resistant, porous molded body is obtained after drying can.
• the high-viscosity suspension may comprise additives in the form of water repellents, in particular synthetic or natural oils, paraffins, waxes or organosilicon compounds and / or additives in the form of flameproofing and / or anti-corrosive agents and / or antifungal agents , In particular, a mixture of soda and whey are added.
• a further development of the invention provides for organic blowing agents in the form of azobisisobutyronitrile, azodicarbonamide, in particular activated azodicarbonamide, dinitropentamethylenetetramine, hydrazodicarbonamide, oxibisulfohydrazide, oxybisbenzenesulfo-hydrazide, 5-phenyltetrazole, para-toluenesulfonyl semicarbazide, toluene / benzene sulfohydrazide and salts thereof, in particular Alkali and alkaline earth metal salts of the highly viscous suspension are added.
• ammonium carbonate sodium bicarbonate, preferably in admixture with potassium bicarbonate and an acid carrier, in particular disodium dihydrogen diphosphate, calcium dihydrogen phosphate or calcium citrate, and aluminum powder can be added both in the acidic and in the basic medium of the highly viscous suspension.
• the organic or inorganic blowing agents may be used either alone or as mixtures of at least two thereof in proportions of from 0.25% by weight to 20% by weight based on the dry weight.
• sulphite or sulphate pulp waste liquor and turpentine oil may be added to the high-viscosity suspension become.
• gelling agent alginates, flour or starch from cereals, potatoes, maize, peas or rice and / or crosslinking agents, in particular based on methylcellulose or glutin, may be added to the high-viscosity suspension become.
• a variant of the invention provides that synthetic additives, in particular isocyanates and polymers, in particular polyvinyl alcohol, polyethylene glycol, polyvinyl acetate and alums, be added for regulating the pH, preferably in small amounts, in order to widen the property spectrum of the shaped bodies.
• the additives can be used either alone or as mixtures of at least two of them, in particular in amounts of from 0.2% by mass to 35% by mass, preferably in amounts of from 3% by mass to 15% by mass, based on the dry mass.
• lignocellulosic foam An important component for the production of lignocellulosic foam is the fiber pulping. The actual process of foaming takes place either by adding a blowing agent or by vigorous stirring to a foamy consistency. Finally, the foam cures on thermal dehydration.
• the ground plant matter is separated by means of a sieve from the excess water to obtain the mass called highly viscous suspension.
• the plant mass of high-viscosity consistency can be formed according to the following embodiments to the desired porous shaped body.
• the prepared high-viscosity suspension in molds, which preferably consist of perforated plates or sieves on the bottom and sides or perforated plates and / or sieves, poured and finally dried under thermal dehydration, for example by microwave drying, in a steam autoclave or in a drying oven.
• lignocellulosic fibers Essential for the successful receipt of the new product is the use of a foam-like suspension of lignocellulosic fibers. These are required for a certain gas holding capacity and for good cohesion of the finished product, a synthetic binder is not required. The higher the degree of disintegration of the fibers, the better the cohesion.
• By selectively varying the degree of mechanical disintegration of the lignocelluloses, the water content and the manner of producing the porous structure e.g.
• chemical or physical foaming or a combination of both methods optionally with or without additives, the density and properties of the lignocellulosic foam can be controlled in a targeted manner.
• the combination with hydrogen peroxide as blowing agent is particularly well suited.
• the product is a solid, dimensionally stable foam, which is odorless and can be processed like other wood-based materials.
• This new lightweight material is suitable as a lightweight board, for Dämm includinge, as packaging material, acoustic element, toy and for a variety of shaped bodies with a cellular structure. It is suitable as a light middle layer in sandwich constructions, as it can be veneered on both sides.
• the porous structure enables a significant reduction in thermal conductivity and sound transmission.
• additives for example water repellents, such as synthetic or natural oils, paraffins, waxes, organosilicon compounds, flameproofing agents and / or antifungal agents, for example synthetic or natural, such as a mixture of soda and whey. Due to the flowable Consistency can be produced any 3D (three-dimensional) structures. Without the specific addition of fungicides, the foams are on prolonged storage in a humid environment, eg. B. in the soil, rotting in an acceptable time.
• water repellents such as synthetic or natural oils, paraffins, waxes, organosilicon compounds, flameproofing agents and / or antifungal agents, for example synthetic or natural, such as a mixture of soda and whey. Due to the flowable Consistency can be produced any 3D (three-dimensional) structures. Without the specific addition of fungicides, the foams are on prolonged storage in a humid environment, eg. B. in the soil, rotting in an acceptable time.
• the fibers can be acetylated before crushing, so that the water absorption capacity of the fibers is reduced. Due to the porosity of the molding remains itself wasserabilitycopy.
• An adaptation to the desired compressive strength can be achieved by a mixture of different fiber lengths.
• the spectrum of the fiber lengths is between 200 .mu.m and 2500 .mu.m, with an increase in compressive strength by adding longer fibers to the fiber suspension with a proportion of between 5% and 50% of fibers having a fiber length between 1000 .mu.m and 2500 .mu.m.
• the compressive strength can be increased by the wood species and / or the addition of natural binders such as starch, lignosulfonate, proteins, for example in a proportion of 2 to 20%.
• the resulting molded article is suitable for use in humid environments due to the waterproof bond. It has a low thickness swelling and is stable again after drying.
• the fiber lengths used in particular the mixture of groups of different fiber lengths, and the wood fibers used, the densities and strengths of the final product can be adjusted. Alignment of the fibers is not necessary for this, but the fibers are undirected in the molding.
• An adjustment of the density of the molding can be done, for example, by changing the amount of long fibers.
• the density of the molded article lowers, as does the use of a higher amount of emulsifiers, such as surfactants or proteins, which cause a higher amount of trapped gas and thereby a lowering of the density.
• emulsifiers such as surfactants or proteins
• the water absorption capacity of the molded article depends on the type of wood used, with softwoods having a lower water absorption capacity than hardwoods.
• Hydrophobic additives such as waxes or silanes can be used to impregnate wood fibers, which generally tend to absorb water. Fiber pretreatment such as acetylation also reduces water absorbency.
• the ability of the shaped body to absorb sound is adjusted via the density and the porosity, the greater the porosity and thus the lower the density, the higher the sound absorption of the respective shaped body.
• the fiber properties can be influenced, for example by the already described hydrophobization by acetylation and / or the addition of waxes and / or melamine in an amount of 1% -15%. If a hydrophilization of the fibers is desired, this can be improved by high temperature of 160 ° C -180 ° C. An addition of acrylates, urea, melamine, glyoxal and / or glycolic acid (2% -20%) in the refining process can strengthen the bonding of the fibers to each other.
• Improved elasticity of the molded articles may be provided by the addition of rubber (10% -60%) or by the addition of polyurethane (10% -60%).
• rubber 10% -60%) or by the addition of polyurethane (10% -60%).
• polyurethane 10% -60%).
• a suspension of beech fibers (TMP) or pine fibers and water is further fiberized in an atmospheric refiner at room temperature. Subsequently, the highly viscous wood fiber suspension is removed through a sieve of excess water and adjusted to a solids content of 10% to 15%. 1000 g of highly viscous suspension is added with a proportionate 5% to 35% hydrogen peroxide (35% in water) for up to four minutes in an intensive mixer Room temperature stirred. The homogeneous, flowable mass is filled in a form perforated on all sides and dried at 130 ° C for 6 to 20 hours in an oven. The resulting lignocellulosic foams have densities between 50 kg / m 3 of 250 kg / m 3 and density-dependent compressive strengths of 20 kPa up to 350 kPa at 10% compression on.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Paper (AREA)

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• 2017
  • 2017-05-22 DE DE102017111139.5A patent/DE102017111139A1/de not_active Withdrawn
• 2018
  • 2018-05-21 US US15/984,766 patent/US10619303B2/en active Active
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