CA2175229C - Process for the production of a fibrous sheet material - Google Patents
Process for the production of a fibrous sheet material Download PDFInfo
- Publication number
- CA2175229C CA2175229C CA002175229A CA2175229A CA2175229C CA 2175229 C CA2175229 C CA 2175229C CA 002175229 A CA002175229 A CA 002175229A CA 2175229 A CA2175229 A CA 2175229A CA 2175229 C CA2175229 C CA 2175229C
- Authority
- CA
- Canada
- Prior art keywords
- layer
- laying
- fibrous
- wet
- sheet material
- 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
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/18—Auxiliary operations, e.g. preheating, humidifying, cutting-off
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F9/00—Complete machines for making continuous webs of paper
Abstract
A fibrous shoe; material is produced by the steps of dry-laying cellulosic fibres on a continuously moving support to form a layer thereon, and wetting said layer sufficiently to cause hydrogen bonds to be formed to a desired degree. The fibrous sheet material thus produced may, if desired, be further processed or finished by known methods to obtain a variety of final products. For carrying out the method an apparatus may be used, which in a preferred embodiment comprises a dry-laying fibre distributor mounted above the foraminous wire of a paper machine based on wet-laying.
Description
PROCESS FOR 1'HE PRODUCTION OF A FIBROUS SHEET MATERIAL
This invention relates to a process for the production of a fibrous sheet material mainly consisting of cellulosic fibres.
Industrial paper-making, based on the wet process has been in commercial use for more than a hundred years.
The industrialisation and commercialisation of air-laid paper have been practiced for ten to twenty years and although this process is on its way to replacing the wet process in the production of certain soft products, there are drawbacks which have to be eliminated before all paper products can be commercially produced by the air-laying process.
=
Using the air laying process fibres are laid down dry, or practically dry, on the wire, e.g. by using the apparatus described in US patent No. 3,575,749 and in patents in other countries.
It is a fact that only very few types of fibrous products (mostly the softer varieties and Formica products) are made industrially using the air-laying process.
The air-laying process has advantages over the wet-laying process regarding energy, space for equipment, pollution, manpower and plant cost, and it would be extremely profitable for the paper industry if the two processes could be combined.
The wet process normally requires the use of 100 times more water than fibres.
The dry process has the disadvantage that it does not produce hydrogen bonds, which is a necessity for the manufacture of most types of paper. Sometimes expensive latex or heat activatable fibres must be used to compensate for the lack of hydrogen bonds.
To produce one ton of paper using the traditional wet process, one has to use 100,000 litres of water which predominantly serves to carry the fibres to the wire. However, this vast amount of water is not necessary for the creation of hydrogen bonds in the paper product. Out of the said 100,000 litres of water, about 99~ is only used for a fraction of a second on the wire, and is then sucked away, or pressed out from the fibrous layer using heavy and energy-consuming machinery.
Using the wet process it is impossible to make a 1-ply product of an acceptable quality -e. g. for use as toilet paper and facial tissues - because there is too much hydrogen bonding for such products, with the result that the paper is too stiff. Therefore when producing soft products using the wet process, it is necessary to produce 2 or 3 very thin plies of the fibrous products and to combine these plies to a final product operating separate equipment. In other words, to make 1000 metres of a 2 to 3 ply paper product, like facial tissues or toilet paper etc., it is necessary to produce 2 to 3000 meters of a 1-ply product, before the layers are combined.
The process of the invention comprises, after removing or closing down the head-box, adding to said layer an aqueous medium in an amount of from 0.3 to 1 part by weight of water per part by weight of the defibrated material while maintaining a subatmospheric pressure in a zone below the support and opposite where aqueous medium is added to the fibre layer in order to improve the penetration of aqueous medium into the fibre layer, causing hydrogen bonds to be formed to a controlled degree within said fibrous layer, drying and, processing the fibrous layer further to form the desired fibrous sheet material.
DESCRIPTION OFTHE DRAWING
In the drawing, Fig. 1 is a side view of the apparatus according to the present invention.
A particularly preferred embodiment of the invention is suitable for use in connection with a conventional wet-laying paper machine and the invention will now be described in - 2a -further detail with reference to such a machine. It should be understood however, that the advantages obtained by the process of the invention can also be achieved by using an apparatus specifically designed for the production of_fibrous sheet material by said process.
wo 9snzozo By using the process of the invention in connection with a conventional wet-laying paper machine the head-box, or other wet-laying equipment normally used for uniformly distributing the fibres on the forming wire, is bypassed, closed down or replaced by an air-laying head, preferably placed in such a manner that there is suction . 5 underneath the wire. This suction might be obtained through the use of suction equipment normally employed in the wet process, or another simpler vacuum installation 4. The defibrated fibres can be distributed in a dry state or almost dry state (by means of said dry-forming distributor which thus functions as an "air-laying head-box").
The aqueous solution or water is preferably supplied to the fibrous layer with the vacuum still maintained under the wire. This suction maintains a subatmospheric pressure in a zone below this supply wne to improve the penetration of the aqueous solution into the fibrous layer. The amount of water to be supplied to the dry-laid is paper is determined by taking into account the amount of water necessary for the required degree of hydrogen bonding. According to the invention, only a small fraction of the quantity of water normally necessary for the wet-laying process is added to the air-laid fibrous layer on the wire, to control the degree of hydrogen bonding. Thus, a fibrous felt is obtained suitable for use in the manufacture of practically all paper products including soft products, writing and printing paper or board products.
Hydrogen bond is produced by adding less than one part water per part fibre.
The aqueous solution is preferably added in an amount sufficient to obtain a water content in the fibrous layer of from about 0.4 to about 0.6 and more preferably for many products about 0.5 parts by weight of water per part by weight of fibrous material. The amount of water added to the dry-laid paper is thus far below the vast amounts used in a wet-laying process.
when the fibres have been distributed on the wire by the air-laying process and a certain amount of water has been added, the paper-felt is normally passed onto the 2~ ~5~~9 w0 95112020 PCTIDK94100398 normal finishing equipment generally used in the wet paper industry. For instance, it is advantageous in the making of soft products to subject the fibrous material to a creping operation on a creping cylinder. Thus it is possible to obtain a great saving in the use of binders, because the process takes advantage of the hydrogen bonding without creating excessive hydrogen bonding. Thus paper (even with a weight per m2 of 30-100g) can be made as soft as required by controlling the amount of water supplied after the fibres are air-laid. On the other hand, it is possible to prepare harder products, such as writing paper, by using calender rolls in the conventional manner.
The dry-laid fibrous layer has a three dimensional structure whereas a fibrous layer prepared by wet-laying mostly is orientated two-dimensionally. When substituting the wet-laying head-box by a dry-laying head-box, the fibres become more entangled in one another, and when hydrogen-bonding is created, or a binder is added, this en-tanglement is maintained so as to form a product having an improved cross machine strength.
The invention also relates to an apparatus for carrying out the process described above.
This apparatus comprises a fibre distributor 1 mounted above a continously movable permeable support 2 with supporting rollers 3, so as to form a layer 7 of a defibrated cellulosic material on said movable permeable support 2. The apparatus also comprises means 5 for adding an aqueous solution to said layer in an amount of 0.3 to 1.0 part by weight of water per part by weight of the defibrated material.
In a preferred embodiment of the invention, a dry-laying fibre distributor 1 is mounted above the foraminous wire of a paper machine based on wet-laying, whereas the finishing of the paper product 7 takes place by conventional creping cylinder 6.
Thus it is possible to transform existing wet-forming plants making various paper products, (tissue products, board and normal writing paper etc.), just by placing an air-laying head-box above the wire where the wet-forming normally begins, and to use R'O 95!12020 2 ~ ~ ~ 2 ~ 9 PC1'IDK94100398 such plants for production of their normal range of products.
By saving up to 99.75 ~ of the water used in wet-laying, it is possible to considerably reduce the amount of energy normally used for the fibre distribution and for the 5 removal of the huge quantity of water from a wet-laid fibrous layer and also improve the quality of the products.
,_."~" .
"-:
This invention relates to a process for the production of a fibrous sheet material mainly consisting of cellulosic fibres.
Industrial paper-making, based on the wet process has been in commercial use for more than a hundred years.
The industrialisation and commercialisation of air-laid paper have been practiced for ten to twenty years and although this process is on its way to replacing the wet process in the production of certain soft products, there are drawbacks which have to be eliminated before all paper products can be commercially produced by the air-laying process.
=
Using the air laying process fibres are laid down dry, or practically dry, on the wire, e.g. by using the apparatus described in US patent No. 3,575,749 and in patents in other countries.
It is a fact that only very few types of fibrous products (mostly the softer varieties and Formica products) are made industrially using the air-laying process.
The air-laying process has advantages over the wet-laying process regarding energy, space for equipment, pollution, manpower and plant cost, and it would be extremely profitable for the paper industry if the two processes could be combined.
The wet process normally requires the use of 100 times more water than fibres.
The dry process has the disadvantage that it does not produce hydrogen bonds, which is a necessity for the manufacture of most types of paper. Sometimes expensive latex or heat activatable fibres must be used to compensate for the lack of hydrogen bonds.
To produce one ton of paper using the traditional wet process, one has to use 100,000 litres of water which predominantly serves to carry the fibres to the wire. However, this vast amount of water is not necessary for the creation of hydrogen bonds in the paper product. Out of the said 100,000 litres of water, about 99~ is only used for a fraction of a second on the wire, and is then sucked away, or pressed out from the fibrous layer using heavy and energy-consuming machinery.
Using the wet process it is impossible to make a 1-ply product of an acceptable quality -e. g. for use as toilet paper and facial tissues - because there is too much hydrogen bonding for such products, with the result that the paper is too stiff. Therefore when producing soft products using the wet process, it is necessary to produce 2 or 3 very thin plies of the fibrous products and to combine these plies to a final product operating separate equipment. In other words, to make 1000 metres of a 2 to 3 ply paper product, like facial tissues or toilet paper etc., it is necessary to produce 2 to 3000 meters of a 1-ply product, before the layers are combined.
The process of the invention comprises, after removing or closing down the head-box, adding to said layer an aqueous medium in an amount of from 0.3 to 1 part by weight of water per part by weight of the defibrated material while maintaining a subatmospheric pressure in a zone below the support and opposite where aqueous medium is added to the fibre layer in order to improve the penetration of aqueous medium into the fibre layer, causing hydrogen bonds to be formed to a controlled degree within said fibrous layer, drying and, processing the fibrous layer further to form the desired fibrous sheet material.
DESCRIPTION OFTHE DRAWING
In the drawing, Fig. 1 is a side view of the apparatus according to the present invention.
A particularly preferred embodiment of the invention is suitable for use in connection with a conventional wet-laying paper machine and the invention will now be described in - 2a -further detail with reference to such a machine. It should be understood however, that the advantages obtained by the process of the invention can also be achieved by using an apparatus specifically designed for the production of_fibrous sheet material by said process.
wo 9snzozo By using the process of the invention in connection with a conventional wet-laying paper machine the head-box, or other wet-laying equipment normally used for uniformly distributing the fibres on the forming wire, is bypassed, closed down or replaced by an air-laying head, preferably placed in such a manner that there is suction . 5 underneath the wire. This suction might be obtained through the use of suction equipment normally employed in the wet process, or another simpler vacuum installation 4. The defibrated fibres can be distributed in a dry state or almost dry state (by means of said dry-forming distributor which thus functions as an "air-laying head-box").
The aqueous solution or water is preferably supplied to the fibrous layer with the vacuum still maintained under the wire. This suction maintains a subatmospheric pressure in a zone below this supply wne to improve the penetration of the aqueous solution into the fibrous layer. The amount of water to be supplied to the dry-laid is paper is determined by taking into account the amount of water necessary for the required degree of hydrogen bonding. According to the invention, only a small fraction of the quantity of water normally necessary for the wet-laying process is added to the air-laid fibrous layer on the wire, to control the degree of hydrogen bonding. Thus, a fibrous felt is obtained suitable for use in the manufacture of practically all paper products including soft products, writing and printing paper or board products.
Hydrogen bond is produced by adding less than one part water per part fibre.
The aqueous solution is preferably added in an amount sufficient to obtain a water content in the fibrous layer of from about 0.4 to about 0.6 and more preferably for many products about 0.5 parts by weight of water per part by weight of fibrous material. The amount of water added to the dry-laid paper is thus far below the vast amounts used in a wet-laying process.
when the fibres have been distributed on the wire by the air-laying process and a certain amount of water has been added, the paper-felt is normally passed onto the 2~ ~5~~9 w0 95112020 PCTIDK94100398 normal finishing equipment generally used in the wet paper industry. For instance, it is advantageous in the making of soft products to subject the fibrous material to a creping operation on a creping cylinder. Thus it is possible to obtain a great saving in the use of binders, because the process takes advantage of the hydrogen bonding without creating excessive hydrogen bonding. Thus paper (even with a weight per m2 of 30-100g) can be made as soft as required by controlling the amount of water supplied after the fibres are air-laid. On the other hand, it is possible to prepare harder products, such as writing paper, by using calender rolls in the conventional manner.
The dry-laid fibrous layer has a three dimensional structure whereas a fibrous layer prepared by wet-laying mostly is orientated two-dimensionally. When substituting the wet-laying head-box by a dry-laying head-box, the fibres become more entangled in one another, and when hydrogen-bonding is created, or a binder is added, this en-tanglement is maintained so as to form a product having an improved cross machine strength.
The invention also relates to an apparatus for carrying out the process described above.
This apparatus comprises a fibre distributor 1 mounted above a continously movable permeable support 2 with supporting rollers 3, so as to form a layer 7 of a defibrated cellulosic material on said movable permeable support 2. The apparatus also comprises means 5 for adding an aqueous solution to said layer in an amount of 0.3 to 1.0 part by weight of water per part by weight of the defibrated material.
In a preferred embodiment of the invention, a dry-laying fibre distributor 1 is mounted above the foraminous wire of a paper machine based on wet-laying, whereas the finishing of the paper product 7 takes place by conventional creping cylinder 6.
Thus it is possible to transform existing wet-forming plants making various paper products, (tissue products, board and normal writing paper etc.), just by placing an air-laying head-box above the wire where the wet-forming normally begins, and to use R'O 95!12020 2 ~ ~ ~ 2 ~ 9 PC1'IDK94100398 such plants for production of their normal range of products.
By saving up to 99.75 ~ of the water used in wet-laying, it is possible to considerably reduce the amount of energy normally used for the fibre distribution and for the 5 removal of the huge quantity of water from a wet-laid fibrous layer and also improve the quality of the products.
,_."~" .
"-:
Claims
1. A process for the production of a fibrous sheet material, mainly consisting of cellulosic fibres, wherein a layer of dry defibrated cellulosic material deposited on a continuously moving support foraminous wire of a paper machine based on wet-laying and having a head-box, characterized in, after removing or closing down the head-box, adding to said layer an aqueous medium in an amount of from 0.3 to 1 part by weight of water per part by weight of the defibrated material while maintaining a subatmospheric pressure in a zone below the support and opposite where the aqueous medium is added to the fibre layer in order to improve the penetration of aqueous medium into the fibre layer, causing hydrogen bonds to be formed to a controlled degree within said fibrous layer, drying and, processing the fibrous layer further to form the desired fibrous sheet material.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14192293A | 1993-10-28 | 1993-10-28 | |
| US08/141,922 | 1993-10-28 | ||
| PCT/DK1994/000398 WO1995012020A1 (en) | 1993-10-28 | 1994-10-28 | Process for the production of a fibrous sheet material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2175229A1 CA2175229A1 (en) | 1995-05-04 |
| CA2175229C true CA2175229C (en) | 2000-04-18 |
Family
ID=22497824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002175229A Expired - Fee Related CA2175229C (en) | 1993-10-28 | 1994-10-28 | Process for the production of a fibrous sheet material |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0725851B1 (en) |
| AT (1) | ATE170240T1 (en) |
| AU (1) | AU7990194A (en) |
| CA (1) | CA2175229C (en) |
| DE (1) | DE69412846T2 (en) |
| WO (1) | WO1995012020A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1291601B1 (en) * | 1997-04-18 | 1999-01-11 | Giuseppe Locati | PROCESS AND PLANT FOR THE PRODUCTION OF PAPER AND CARDBOARD STARTING FROM WASTE PAPER |
| SE539948C2 (en) | 2016-03-18 | 2018-02-06 | The Core Company Ab | Isostatic pressure forming of heated dry cellulose fibers |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE340264B (en) * | 1967-01-05 | 1971-11-15 | K Kroeyer | |
| SE399015B (en) * | 1976-10-06 | 1978-01-30 | Reinhall Rolf | WAY TO MAKE FIBER PLATES |
-
1994
- 1994-10-28 AU AU79901/94A patent/AU7990194A/en not_active Abandoned
- 1994-10-28 EP EP95915047A patent/EP0725851B1/en not_active Expired - Lifetime
- 1994-10-28 DE DE69412846T patent/DE69412846T2/en not_active Expired - Fee Related
- 1994-10-28 CA CA002175229A patent/CA2175229C/en not_active Expired - Fee Related
- 1994-10-28 AT AT95915047T patent/ATE170240T1/en not_active IP Right Cessation
- 1994-10-28 WO PCT/DK1994/000398 patent/WO1995012020A1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| EP0725851A1 (en) | 1996-08-14 |
| WO1995012020A1 (en) | 1995-05-04 |
| DE69412846T2 (en) | 1999-02-11 |
| DE69412846D1 (en) | 1998-10-01 |
| CA2175229A1 (en) | 1995-05-04 |
| ATE170240T1 (en) | 1998-09-15 |
| EP0725851B1 (en) | 1998-08-26 |
| AU7990194A (en) | 1995-05-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |