CA2142222C - Process for producing foamed material from waste paper and the like - Google Patents
Process for producing foamed material from waste paper and the like Download PDFInfo
- Publication number
- CA2142222C CA2142222C CA002142222A CA2142222A CA2142222C CA 2142222 C CA2142222 C CA 2142222C CA 002142222 A CA002142222 A CA 002142222A CA 2142222 A CA2142222 A CA 2142222A CA 2142222 C CA2142222 C CA 2142222C
- Authority
- CA
- Canada
- Prior art keywords
- liquid
- paper pulp
- mold
- microwave radiation
- fibers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- 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
- D21J1/06—Drying
-
- 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
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F5/00—Dryer section of machines for making continuous webs of paper
- D21F5/16—Drying webs by electrical heating
- D21F5/167—Microwave heating
Landscapes
- Paper (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Abstract
A process for the production of foamed material from waste paper and the like, such as paper, cardboard, waste cardboard or materials with similar properties, are usable in the same way as raw material, either sorted by type of material or as a raw material mixture. First, a liquid-containing pulp is prepared from the raw materials. The foaming and hardening of this pulp takes place under the action of microwave radiation. By using suitable molds permitting an unobstructed access of the radiation to the liquid-containing mass and unhindered expulsion of the resulting vapor, it is possible to manufacture any type of shaped bodies in a continuous or batch-wise process.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a process for producing foamed material from waste paper and similar materials.
Paper, cardboard, waste cardboard or materials with similar properties are usable as raw materials in the same way, either sorted according to type or as a raw material mixture. The invention is intended to preferably make a contribution to environmental protection by the recovery and treatment of secondary raw materials that are available in substantial quantities.
It is possible by the process according to the invention to produce different final products, in particular construction elements for thermal insulation and for sound damping, as well as elements for vibration absorption and shock absorption. Other final products include roof covering panels or wall lining panels, composite boards, and other shaped bodies for use as filler material for insulation and packing purposes. Special treatments to the final product are possible by adding, for example, hydrophobic agents, fireproofing agents, rot-inhibiting agents or reaction aids.
The above enumerations are to be understood as given by way of example.
In the state of the art it is known that several processes for the manufacture of such products are already known.
Furthermore, suitable devices for carrying out such processes for and producing the final product itself can be found in the documented state of the art. With respect to the state of the art, reference is made to the following listed documents:
DE 31 14 527; DE 33 07 736; DE 34 20 195; DE 34 44 264; DE 35 10 214;
DE 35 22 395; DE 36 24 164; DE 36 41 464; DE 37 04 309; DE 37 18 545;
DE 39 00 289; DE 40 25 694; DE 41 35 069; DE 92 00 066; DE 92 16 620;
DE 93 03 498.
An important known process step is the preparation of a liquid or aqueous pulp from these raw materials, which is referred to below as the "paper pulp", including the steps of cutting up and mixing of the components.
These preparatory measures are not the subject matter of the invention, but are only made use of. Of special importance is the heat treatment of the paper pulp made available.
The present invention relates to a process for producing foamed material from waste paper and similar materials.
Paper, cardboard, waste cardboard or materials with similar properties are usable as raw materials in the same way, either sorted according to type or as a raw material mixture. The invention is intended to preferably make a contribution to environmental protection by the recovery and treatment of secondary raw materials that are available in substantial quantities.
It is possible by the process according to the invention to produce different final products, in particular construction elements for thermal insulation and for sound damping, as well as elements for vibration absorption and shock absorption. Other final products include roof covering panels or wall lining panels, composite boards, and other shaped bodies for use as filler material for insulation and packing purposes. Special treatments to the final product are possible by adding, for example, hydrophobic agents, fireproofing agents, rot-inhibiting agents or reaction aids.
The above enumerations are to be understood as given by way of example.
In the state of the art it is known that several processes for the manufacture of such products are already known.
Furthermore, suitable devices for carrying out such processes for and producing the final product itself can be found in the documented state of the art. With respect to the state of the art, reference is made to the following listed documents:
DE 31 14 527; DE 33 07 736; DE 34 20 195; DE 34 44 264; DE 35 10 214;
DE 35 22 395; DE 36 24 164; DE 36 41 464; DE 37 04 309; DE 37 18 545;
DE 39 00 289; DE 40 25 694; DE 41 35 069; DE 92 00 066; DE 92 16 620;
DE 93 03 498.
An important known process step is the preparation of a liquid or aqueous pulp from these raw materials, which is referred to below as the "paper pulp", including the steps of cutting up and mixing of the components.
These preparatory measures are not the subject matter of the invention, but are only made use of. Of special importance is the heat treatment of the paper pulp made available.
The known technical solutions for the heat treatment of the paper pulp are, without exception, based on conventional processes, devices or installations.
The term "conventional" is understood to mean the following:
- the expansion of the mass is achieved through the introduction of heat at temperatures from 120°C to 140°C;
- the heat treatment at temperatures above 200°C with water vapor saturation in an autoclave;
- the thermal and mechanical introduction of energy in the extruder; upon exiting from the extruder, the mass foams up due to the drop in temperature and pressure;
- heating under pressure application in general; and - treatment with hot air and steam.
The term "conventional" is understood to mean the following:
- the expansion of the mass is achieved through the introduction of heat at temperatures from 120°C to 140°C;
- the heat treatment at temperatures above 200°C with water vapor saturation in an autoclave;
- the thermal and mechanical introduction of energy in the extruder; upon exiting from the extruder, the mass foams up due to the drop in temperature and pressure;
- heating under pressure application in general; and - treatment with hot air and steam.
All of these processes are characterized by high energy requirement, which often is associated with considerable financial expenditure in terms of equipment, which in turn results from the large number of process steps. These processes predominantly work discontinuously because the large amounts of energy required cannot be introduced within the shortest possible time. The evaporation of liquid is characterized by a certain time delay and inertia. For this reason, the prior art efficiency is adequate only for a limited number of applications.
The after-treatment and special treatments, if any, are, like the preparation of the paper pulp, not the subject matter of the process according to the invention. In this regard, tested means and methods are used.
SUMMARY OF THE INVENTION
It is an object of the present invention to reduce the time required to carry out the known processes, which is a precondition for permitting the process to be carried out continuously, and for permitting a reduction in the financial expenditure for equipment and for a reduction in any heat losses.
The after-treatment and special treatments, if any, are, like the preparation of the paper pulp, not the subject matter of the process according to the invention. In this regard, tested means and methods are used.
SUMMARY OF THE INVENTION
It is an object of the present invention to reduce the time required to carry out the known processes, which is a precondition for permitting the process to be carried out continuously, and for permitting a reduction in the financial expenditure for equipment and for a reduction in any heat losses.
According to the present invention, the above object is achieved as follows:
It is known that a paper pulp mixed with liquid foams up during treatment with thermal energy, when the liquid starts to evaporate. The foaming effect can be increased by further additions of thermal energy.
This process is based on the fact that the change of state of a liquid into the gaseous phase is associated with a considerable increase in volume. The vapor flowing off from the paper pulp creates the number of flow paths that are required to enable the vapor to escape. The solidification of the paper pulp begins upon the withdrawal of the liquid therefrom and permits the flow paths to remain preserved as hollow spaces.
The solution of the prior art problems according to the present invention starts at this point.
According to the invention, the paper pulp is subjected to microwave radiation instead of being subjected to the conventional heat treatment, with such microwave radiation preferably being in the range of 915 MHz and 2.45 GHz.
It is known that a paper pulp mixed with liquid foams up during treatment with thermal energy, when the liquid starts to evaporate. The foaming effect can be increased by further additions of thermal energy.
This process is based on the fact that the change of state of a liquid into the gaseous phase is associated with a considerable increase in volume. The vapor flowing off from the paper pulp creates the number of flow paths that are required to enable the vapor to escape. The solidification of the paper pulp begins upon the withdrawal of the liquid therefrom and permits the flow paths to remain preserved as hollow spaces.
The solution of the prior art problems according to the present invention starts at this point.
According to the invention, the paper pulp is subjected to microwave radiation instead of being subjected to the conventional heat treatment, with such microwave radiation preferably being in the range of 915 MHz and 2.45 GHz.
The advantages of this method for introducing energy are based on the fact that with microwaves, as opposed to heat radiation, it is possible to realize very high energy densities. In addition, the energy acts on the paper pulp not merely at the surface, but also penetrates into the paper pulp and directly heats the liquid, causing the latter to evaporate. With a suitable high energy density, the heat treatment takes place with such violence that the resulting vapor, by creating paths for its expulsion from the volume of the paper pulp exposed to this penetrating radiation, leads to an expansion of the paper pulp mass, which creates porosity within the mass.
Since this process, due to the evaporation of the liquid, is simultaneously a drying process, a solidification of the material starts as the volume of the paper pulp increases, with such solidification stabilizing the hollow spaces and porosity created in the paper pulp. The process can be supplemented by adding foaming agents and stabilizing agents.
The process of the invention is based upon the following physical characteristics, the technical implementation of which is the subject matter of the invention.
Since this process, due to the evaporation of the liquid, is simultaneously a drying process, a solidification of the material starts as the volume of the paper pulp increases, with such solidification stabilizing the hollow spaces and porosity created in the paper pulp. The process can be supplemented by adding foaming agents and stabilizing agents.
The process of the invention is based upon the following physical characteristics, the technical implementation of which is the subject matter of the invention.
Microwave radiation is capable of penetrating through materials with a suitable dielectric constant, for example such as glass or paper, without loss of energy. Other materials absorb microwave radiation, i.e., such materials consume the energy of the microwaves. This process is also referred to as coupling to the microwaves. This takes place in the molecular range and is manifest by a heating of the material activated by the microwaves. Such material includes, for example, water in the liquid state.
Accordingly, in a water-containing paper pulp, the energy made available by the microwaves is directly and only transmitted to the water molecules. The heat is generated in the volume subjected to the penetrating through radiation. Thus in the interior of the body, heat is dissipated, and does not have to be transmitted from the outside to the inside as with a heat transfer using a temperature difference as the propelling force. For this reason, a body is uniformly heated under microwave radiation throughout the entire volume irradiated.
Due to heat losses at the surface of the body, the volume-specific amount of heat stored can be even greater in the interior of the body than near its surface. With suitable energy density leading to evaporation of the water, an excess pressure is generated in the interior of the through-irradiated body volume, such excess pressure leading to expulsion of the water vapor in the direction of the surface of the body.
If the irradiated body is dimensionally unstable, as it is the case with the paper pulp considered here, flow paths are created in the body in the form of hollow spaces by the steam being expelled. The body takes on a porous structure and breaks up considerably. Its volume increases. Since a hardening process starts in this stage at the same time due to drying of the material, such voluminous and porous structure remains preserved.
Certain additions such as binding agents or foaming agents promote this process.
This means a substantial simplification of the after-treatment in terms of process engineering. If necessary, after-treatment process steps are eliminated.
A technical procedure for the implementation of this process for the manufacture of foamed material, particularly of shaped bodies, depends on the desired result of the production, and it can be carried out both batch-wise (discontinuously) and continuously. This depends upon the shape of the mold.
In terms of equipment, it is necessary to make sure that a largely unobstructed irradiation with microwaves is possible, _ g -taking into account the increase in volume of the paper pulp, and that the water vapor can be expelled from the mold unhindered at the same time.
Further treatment steps can be used in the process for producing a foamed material product according to the invention. For example, there can be a vacuuming off of the vapor of the liquid generated due to the introduction of microwave radiation. This is followed by condensing the vapor back to a liquid; and then recycling and reusing the liquid again for the treatment of the paper pulp.
While several embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention as defined in the appended claims.
Accordingly, in a water-containing paper pulp, the energy made available by the microwaves is directly and only transmitted to the water molecules. The heat is generated in the volume subjected to the penetrating through radiation. Thus in the interior of the body, heat is dissipated, and does not have to be transmitted from the outside to the inside as with a heat transfer using a temperature difference as the propelling force. For this reason, a body is uniformly heated under microwave radiation throughout the entire volume irradiated.
Due to heat losses at the surface of the body, the volume-specific amount of heat stored can be even greater in the interior of the body than near its surface. With suitable energy density leading to evaporation of the water, an excess pressure is generated in the interior of the through-irradiated body volume, such excess pressure leading to expulsion of the water vapor in the direction of the surface of the body.
If the irradiated body is dimensionally unstable, as it is the case with the paper pulp considered here, flow paths are created in the body in the form of hollow spaces by the steam being expelled. The body takes on a porous structure and breaks up considerably. Its volume increases. Since a hardening process starts in this stage at the same time due to drying of the material, such voluminous and porous structure remains preserved.
Certain additions such as binding agents or foaming agents promote this process.
This means a substantial simplification of the after-treatment in terms of process engineering. If necessary, after-treatment process steps are eliminated.
A technical procedure for the implementation of this process for the manufacture of foamed material, particularly of shaped bodies, depends on the desired result of the production, and it can be carried out both batch-wise (discontinuously) and continuously. This depends upon the shape of the mold.
In terms of equipment, it is necessary to make sure that a largely unobstructed irradiation with microwaves is possible, _ g -taking into account the increase in volume of the paper pulp, and that the water vapor can be expelled from the mold unhindered at the same time.
Further treatment steps can be used in the process for producing a foamed material product according to the invention. For example, there can be a vacuuming off of the vapor of the liquid generated due to the introduction of microwave radiation. This is followed by condensing the vapor back to a liquid; and then recycling and reusing the liquid again for the treatment of the paper pulp.
While several embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (11)
1. A process for producing a foamed material product from raw waste paper comprising:
providing a source of a raw waste paper material;
preparing a starting mixture by mixing paper with a liquid;
said starting mixture containing liquid in an amount sufficient to cause foaming due to a microwave radiation treatment;
applying microwave radiation to said starting mixture to cause foaming of said starting mixture and solidifying the resulting material while said mixture is being treated with microwave radiation.
providing a source of a raw waste paper material;
preparing a starting mixture by mixing paper with a liquid;
said starting mixture containing liquid in an amount sufficient to cause foaming due to a microwave radiation treatment;
applying microwave radiation to said starting mixture to cause foaming of said starting mixture and solidifying the resulting material while said mixture is being treated with microwave radiation.
2. The process as defined in claim 1, wherein said starting mixture contains water in an amount sufficient to permit substantially uniform heating of fibers in said mixture.
3. The process as defined in claim 1, wherein said starting mixture includes at least one additive for modifying the properties of the product obtained by treatment with microwave radiation.
4. The process as defined in claim 1, wherein said starting material contains fibers capable of absorbing water, said fibers having a moisture content sufficient to permit said fibers upon treatment by said microwave radiation to substantially uniform heating of the fibers.
5. The process as defined in claim 1, wherein said starting material is a paper pulp containing water therein.
6. The process as defined in claim 1, wherein said starting material is a paper pulp having fibers capable of absorbing liquid.
7. The process as defined in claim 1, further comprising the steps of:
filling paper pulp containing a liquid into a mold in a required amount, said mold being made from microwave-permeable material not activated by the radiation;
and subjecting said mold and the paper pulp to said radiation whereby the expansion of the paper pulp and evaporation of the liquid are not substantially obstructed by the mold.
filling paper pulp containing a liquid into a mold in a required amount, said mold being made from microwave-permeable material not activated by the radiation;
and subjecting said mold and the paper pulp to said radiation whereby the expansion of the paper pulp and evaporation of the liquid are not substantially obstructed by the mold.
8. The process as defined in claim 1, further comprising the steps of:
vacuuming off vapor of said liquid generated due to the introduction of microwave radiation;
condensing the vapor back to a liquid; and reusing the liquid again for the treatment of the paper pulp.
vacuuming off vapor of said liquid generated due to the introduction of microwave radiation;
condensing the vapor back to a liquid; and reusing the liquid again for the treatment of the paper pulp.
9. The process as defined in claim 2, further comprising:
continuously foaming and shaping said paper pulp depending on the shape of said mold.
continuously foaming and shaping said paper pulp depending on the shape of said mold.
10. The process as defined in claim 2, further comprising:
carrying out the foaming and shaping of the paper pulp batchwise depending on the shape of said mold.
carrying out the foaming and shaping of the paper pulp batchwise depending on the shape of said mold.
11. The process as defined in claim 2 wherein said liquid is water.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4404322.8 | 1994-02-11 | ||
| DE4404322A DE4404322A1 (en) | 1994-02-11 | 1994-02-11 | Process for the production of foamed material from waste paper and the like the like |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2142222A1 CA2142222A1 (en) | 1995-08-12 |
| CA2142222C true CA2142222C (en) | 2000-11-07 |
Family
ID=6510008
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002142222A Expired - Fee Related CA2142222C (en) | 1994-02-11 | 1995-02-10 | Process for producing foamed material from waste paper and the like |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0671504B1 (en) |
| AT (1) | ATE156541T1 (en) |
| CA (1) | CA2142222C (en) |
| DE (2) | DE4404322A1 (en) |
| DK (1) | DK0671504T3 (en) |
| FI (1) | FI105280B (en) |
| NO (1) | NO307191B1 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5707579A (en) * | 1994-02-11 | 1998-01-13 | Schweitzer, Vodermair & Schimmer-Wottrich Gbr | Process for producing foamed material from waste paper and the like |
| EP0740990A3 (en) * | 1995-05-02 | 1997-05-28 | Schweitzer Jacob | Process for defining the various properties of cellulose containing foams |
| DE19546296A1 (en) * | 1995-05-02 | 1996-11-07 | Schweitzer Jacob | Prodn. of cellulose-based foam prods. with defined properties |
| DE19546295A1 (en) * | 1995-12-12 | 1997-06-19 | Schweitzer Jacob | Prodn. of cellulose-based foam prods. with defined properties |
| KR100232121B1 (en) * | 1997-06-10 | 1999-12-01 | 허방욱 | A new manufacturing method of adiabatic material |
| DE10312758A1 (en) * | 2003-03-21 | 2004-09-30 | Saueressig Gmbh & Co. | Manufacturing process for absorbent fiber product and absorbent fiber product |
| WO2005007968A1 (en) * | 2003-07-16 | 2005-01-27 | Fira International Limited | Recycling of lignocellulose based board materials |
| WO2017079169A1 (en) | 2015-11-03 | 2017-05-11 | Kimberly-Clark Worldwide, Inc. | Paper tissue with high bulk and low lint |
| GB201612889D0 (en) * | 2016-07-26 | 2016-09-07 | Natural Resources (2000) Ltd | Moulding of articles |
| GB2582508B (en) | 2017-11-29 | 2022-02-16 | Kimberly Clark Co | Fibrous sheet with improved properties |
| AU2018433810A1 (en) | 2018-07-25 | 2021-02-04 | Kimberly-Clark Worldwide, Inc. | Process for making three-dimensional foam-laid nonwovens |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR873763A (en) * | 1939-09-20 | 1942-07-20 | New fibrous product and manufacturing process | |
| DE3420195A1 (en) * | 1984-05-30 | 1985-12-12 | Friedrich 2807 Achim Priehs | Process for producing insulating material from scrap paper and/or cardboard |
| DE4105245C1 (en) * | 1991-02-20 | 1992-10-22 | Viessmann Werke Gmbh & Co, 3559 Allendorf, De | Rapidly drying moulded bodies - formed by suction on fibrous sludge, placed in enclosed zone at low-pressure |
| DE4207233A1 (en) * | 1992-03-07 | 1993-11-18 | Geier Henninger Kurt | Prodn. of porous filter body for exhaust gas - by saturating paper and/or cardboard material with water, stirring and drying or hardening obtd. foamed pulp |
-
1994
- 1994-02-11 DE DE4404322A patent/DE4404322A1/en not_active Withdrawn
-
1995
- 1995-02-07 AT AT95101694T patent/ATE156541T1/en not_active IP Right Cessation
- 1995-02-07 EP EP95101694A patent/EP0671504B1/en not_active Expired - Lifetime
- 1995-02-07 DE DE59500454T patent/DE59500454D1/en not_active Expired - Fee Related
- 1995-02-07 DK DK95101694.8T patent/DK0671504T3/en active
- 1995-02-10 CA CA002142222A patent/CA2142222C/en not_active Expired - Fee Related
- 1995-02-10 FI FI950589A patent/FI105280B/en active
- 1995-02-10 NO NO950510A patent/NO307191B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE59500454D1 (en) | 1997-09-11 |
| FI105280B (en) | 2000-07-14 |
| FI950589A (en) | 1995-08-12 |
| DE4404322A1 (en) | 1995-08-17 |
| DK0671504T3 (en) | 1998-03-02 |
| EP0671504A1 (en) | 1995-09-13 |
| ATE156541T1 (en) | 1997-08-15 |
| EP0671504B1 (en) | 1997-08-06 |
| NO307191B1 (en) | 2000-02-21 |
| NO950510D0 (en) | 1995-02-10 |
| NO950510L (en) | 1995-08-14 |
| FI950589A0 (en) | 1995-02-10 |
| CA2142222A1 (en) | 1995-08-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20030210 |