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NZ251000A - Wet process board manufacture characterised in that binder is added to the fibrous material prior to dewatering and pressing - Google Patents

Wet process board manufacture characterised in that binder is added to the fibrous material prior to dewatering and pressing

Info

Publication number
NZ251000A
NZ251000A NZ251000A NZ25100093A NZ251000A NZ 251000 A NZ251000 A NZ 251000A NZ 251000 A NZ251000 A NZ 251000A NZ 25100093 A NZ25100093 A NZ 25100093A NZ 251000 A NZ251000 A NZ 251000A
Authority
NZ
New Zealand
Prior art keywords
binder
fibres
stock
added
resin
Prior art date
Application number
NZ251000A
Inventor
Leif Flodman
Jan-Erik Nordqvist
Original Assignee
Casco Nobel Ab
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Casco Nobel Ab filed Critical Casco Nobel Ab
Publication of NZ251000A publication Critical patent/NZ251000A/en

Links

Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21BFIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00Fibrous raw materials or their mechanical treatment
    • D21B1/04Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/14Disintegrating in mills
    • D21B1/16Disintegrating in mills in the presence of chemical agents
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20Macromolecular organic compounds
    • D21H17/33Synthetic macromolecular compounds
    • D21H17/46Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/47Condensation polymers of aldehydes or ketones
    • D21H17/48Condensation polymers of aldehydes or ketones with phenols
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63Inorganic compounds
    • D21H17/66Salts, e.g. alums
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H23/00Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/02Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/04Addition to the pulp; After-treatment of added substances in the pulp
    • D21H23/06Controlling the addition
    • D21H23/14Controlling the addition by selecting point of addition or time of contact between components
    • D21H23/16Addition before or during pulp beating or refining

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Paper (AREA)
  • Dry Formation Of Fiberboard And The Like (AREA)
  • Laminated Bodies (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Cell Separators (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Machines For Manufacturing Corrugated Board In Mechanical Paper-Making Processes (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

In a process for making board according to the wet method, a stock is prepared from fibres produced from a fibrous raw material, and a binder is added prior to dewatering and pressing. The process is distinguished by adding the binder to the fibres before the preparation of the stock. The binder may be a water-soluble binder which is precipitated and fixed to the fibres by acidification. Acidification may take place in connection with the preparation of the stock or prior thereto as well as prior to the addition of the binder. The binder can be added to the fibres in the blow line from the defibrator for producing the fibres from the fibrous raw material, or it may be added to the fibres before the defibrator.

Description

New Zealand Paient Spedficaiion for Paient Number £51 000 New Zealand No. International No. 10 00 251000 PCT/SE93/0 0205 TO BE ENTERED AFTER ACCEPTANCE AND PUBUCATION Priority dates: ' —>1 3^*2.
International filing date: Classification: T l /oo, 3>a\ V\Q3/>4- Pubiication date: 2 6 NOV 1996 Journal No.: iq-IO NO DRAWINGS NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of invention: Process for making board Name, address and nationalitv- of applicant(s) as in international application form: s"100 61 stockholm Sweden 0 0 1 PROCESS FOR MAKING BOARD The present invention relates to a process for making board according to what is commonly referred to as the wet method. More specifically, the invention concerns an 5 improved process for making board, by adding the binder at an early stage of the process. Insulation board, building board and hardboard, for instance, can be produced by this process.
When making board according to the wet method, a 10 stock is prepared from fibres produced from a fibrous raw material, such as chips and sawdust, by mixing the fibres with water in several steps. A binder is added to bind the fibres in the board, whereupon the stock is dewatered and the fibre pulp is pressed. The binder is added to the 15 stock and, if water-soluble, is precipitated and fixed to the fibres by acidification of the stock, e.g. by alum or acid. The binder may be added at a site where the stock concentration is about 5-15%, e.g. in the level box, whereupon precipitation and fixation by acidification take 20 place where the stock concentration is about 2-3%, e.g. in the machine chest. Alternatively, both the addition of the binder and the precipitation thereof on to the fibres may take place in the machine chest.
This process has the disadvantage that the binder, 25 when precipitated, deposits not only on the fibres, but also on the remaining material in the stock. Apart from useful fibres, the stock contains fibre fragments, i.e. what is commonly referred to as fines, as well as dissolved carbohydrate material and, to a certain extent, ligneous 30 substance in dissolved and colloidal form. Since the water in the process is at least partly recycled by using, in the preparation of the stock, the white water from the dewater-ing step, the contents of these by-products will be comparatively high. As a portion of the binder deposits on 35 these components, this portion will be of no avail to the fibre matrix. It has thus become necessary to increase the amount of binder added, which nevertheless 'has not given the desired result in certain cases. The dosage of resin is N.i. PATEN'i i i 16 OCT 1996 RECEIVED 251000 2 L also restricted by the fact that dewater.ing of the stock is rendered more difficult if the amount of resin exceeds a certain level (about 6-8%). In addition, many board manufacturers in Europe have made their processes more or less 5 closed for environmental reasons (reduced discharge of COD-consuming materials to recipients). As a result, the contents of fines and dissolved substances in the white water have increased even further. However, the present invention largely obviates these disadvantages.
One object of the invention is, therefore, to utilize the adhesive on the fibre matrix more effectively in the making of board. Another object of the invention "is to enable dosage of the desired amount of resin on the fibres without affecting the subsequent dewatering.
As appears from the appended claims, the objects of the invention are achieved by a process for manufacture of board according to the wet method by preparation of a stock of fibres, wherein a binder selected from water soluble curing organic or inorganic binders is added to the fibres before preparation of said stock and said binder is precipitated and fixed to the fibres by acidification prior to dewatering said stock and pressing the fibres into a board. It has surprisingly been found that the binder can be utilized far more effectively if added to the fibres early in the process, before the supply of water for preparing the stock, resulting in 25 improved properties of the board. Also, it has become possible to add very large amounts of binder without adversely affecting the subsequent process.
In the process according to the invention, conventional equipment is used for making board according to the 30 wet method. Thus, the wood raw material is conducted, by preheating with steam, to a defibrat^or for disintegration. The resulting fibre pulp is conveyed'through a blow line to chests, where the stock is prepared. Fresh water and/or white water is added to the chests, resulting in a stock 3 5 having a content of about 5-15%. This stock is conducted to a refiner for final adjustment of the beating degree. From the refiner, the stock is conveyed to a machine_chest, where the final dilution with water/white water is per- 2 5 10 0 0 3 formed. At this stage, the stock has a content of about 2-3%. This stock is conducted to a wet machine to be dewater-ed, pressed and dried/press-dried (hot press).
In the process according to the invention, the binder 5 may be added to the fibres at any time before the site where a substantial amount of water is added for preparing the stock. The binder is suitably added in the blow line from the defibrator. Here, the fibres have a dry solids content of about 40-60% by weight. This constitutes a 10 preferred embodiment of the invention. The binder may also be added to the fibres before the defibrator.
In the inventive process, use is made of such binders as are predominant in the art. These are curing organic or inorganic binders, such as phenolic resins, amino resins, 15 silicates or mixtures thereof. Water-soluble binders are generally used. When water-soluble resins are employed, they have to be precipitated and fixed to the fibres, which is brought about by acidification, e.g. by means of alum or acid. Preferably, acidification is performed in 20 connection with the preparation of the stock or prior thereto, and in that case also prior to the addition of the binder, when added in connection with the preparation of the stock, the precipitating reagent may be added to the first dilution chest, where the stock concentration is 25 about 1-15% by weight, usually 5-15% by weight. If acidification is allowed to take place at a late stage of the process, e.g. in the machine chest, there is a risk that some of the water-soluble binder applied to the fibre matrix is dissolved and instead precipitated on the other 30 material in the stock, resulting in impaired performance.
With the present invention, it is also possible to "control" the penetration of resin into the fibre. As a result, the properties of the board can be influenced in different directions, e.g. internal bond strength and 35 modulus of rupture versus swelling and water absorption. If a sparingly soluble or concentrated resin is used, penetration is reduced and the resin is concentrated on the fibre surfaces. This enhances the possibility of obtaining 25100 WO 93/18227 PCT/SE93/00205 4 active glue joints between the fibres, resulting in higher strength. In the opposite case, i.e. when diluted and low-viscosity resins are used, penetration increases, resulting in lower swelling and, above all, lower water absorption. 5 Penetration may also be reduced by adding alum/acid before the defibrator or before the site where the binder is added. Thus, the binder will be precipitated directly on the surface of the acid fibre, and penetration is reduced to a minimum. Consequently, the present invention enables 10 several ways of controlling in a given direction the properties of the end product.
Also, the process according to the invention enables the addition of very large amounts of binder without rendering dewatering on the wet machine more difficult. The 15 prior-art process restricts the dosage of the binder to about 6-8%, requiring at that the aid of certain flocculating chemicals. If the dosage exceeds this level, dewatering from the wire is impeded to such an extent that there is a risk of crushing the sheet in the press section. 20 In the process according to the invention, there are no dosing problems with contents of from about 0.5% by weight to about 40% by weight (based on dry resin on a dry fibre matrix), suitably up to about 15-20% by weight. Generally, the binder is used in an amount of about 0.5-10% by weight, 25 preferably 1-5% by weight.
Making board according to the wet method by the process according to the invention does not influence the other process conditions. The binder can be added through a simple connecting tube on the blow line after the defi-30 brator. The amount of binder is adjusted by a dosing pump. The binder can be precipitated in e.g. a first dilution chest at a stock concentration of about 10% by means of alum. Then, the sized stock is allowed to continue in the process via a refiner, a dilution chest, a machine chest 35 and a wet machine in conventional manner. Thus, the process according to the invention is fairly easy to incorporate in existing processes.
The invention will now be described in more detail 25100 T/SE93/0D2G5 PCT/S .15 with the aid of the following Examples, in which the part and percentage figures concern parts by weight and per cent by weight, unless otherwise stated.
Example 1 The making of insulation board.
Phenolic resin having a concentration of 40% by weight was applied by so-called blow-line dosage immediately after the defibrator through an insert pipe centered in the blow line. Thus, the phenolic resin was applied to concentrated hot fibre having a temperature of about 150°C (a dry solids content of about 50% by weight). The resin was dosed by a suitable dosing pump, and was precipitated and fixed to the fibre at a high stock concentration (8-10%) immediately after the cyclone in the first dilution chest.
Precipitation was brought about by the addition of an alum solution to the diluting water.
The sized fibre (the stock) was then conducted further in the proo -ss via refiners, machine chests and a wet machine in conventional manner.
The board thickness was 13 mm.
Dosing Phenolic resin MOR IB Swelling Water abs. process dosage % MPa MPa 2 h % 2 h % According to the invention 6.5 0.26 1.9 12.4 Added in machine chest typical values* 3.0- 0.08- 2.3-3.5 0.12 3.5 18-30 Standard board 2.7 0.11 7.0 173 *) An addition of wax forms part of this grade.

Claims (11)

2 5 10 0 0 WO 93/18227 PCI7SE93/00205 Example 2 Insulation board 16 mm. The process according to 5 difference being that use phenolic resin of 43% by cosity than the resin used Example 1 was repeated, the only was here made of concentrated weight, i.e. having higher vis-in Example 1. Dosing Phenolic resin MOR IB Swelling Water abs. 10 process dosage % MPa MPa 2 h % 2 h % According to the invention 5 4.0 0.16 3.2 15 15 Added in machine chest 2 2.2 0.07 3.5 22 *) An addition of wax (2%) forms part of this grade. 20 It is apparent how the properties can be controlled towards increased strength by reducing resin penetration, although with lesser effect on swelling and water absorption. 25100 -7- CLAIMS
1. A process for manufacture of board according to the wet method by preparation of a stock of fibres, wherein a binder selected from water soluble curing organic or inorganic binders is added to the fibres before preparation of said stock and said binder is precipitated and fixed to the fibres by acidification prior to dewatering said stock and pressing the fibres into a board.
2. A process as claimed in claim 1, characterised in that acidification takes place in connection with the preparation of the stock.
3. A process as claimed in claim 1. characterised in that acidification takes place before the preparation of the stock.
4. A process as claimed in claim 1, characterised in that acidification takes place before the addition of the binder.
5. A process as claimed in any one of claims 1-4, characterised in that acidification takes place with alum or acid.
6. A process as claimed in claim 1, characterised in that the binder is added to the fibres in the blow line from the defibrator for producing the fibres from the fibrous raw material.
7. . 7. a process as claimed in claim 1, characterised in that the binder is added to the fibres before the defibrator for producing the fibres from the fibrous raw material.
8. A process as claimed in claim 1', characterised in that the binder is a sparingly soluble or concentrated resin.
9. 9- a process as claimed in claim 1, characterised in that the binder is a diluted, low-viscosity resin.
10. A process as claimed in claim 1, charac- N.Z. PATENT OFFICE 16 OCT 1996 RECEIVED 25100 0 8 terised in that the binder is added in an amount of from 0.5% by weight to 40% by weight (based on dry resin on a dry fibre matrix).
11. A process according to claim 1 substantially as herein described or exemplified.
NZ251000A 1992-03-13 1993-03-09 Wet process board manufacture characterised in that binder is added to the fibrous material prior to dewatering and pressing NZ251000A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9200784A SE470101B (en) 1992-03-13 1992-03-13 Procedure for making board

Publications (1)

Publication Number Publication Date
NZ251000A true NZ251000A (en) 1996-11-26

Family

ID=20385615

Family Applications (1)

Application Number Title Priority Date Filing Date
NZ251000A NZ251000A (en) 1992-03-13 1993-03-09 Wet process board manufacture characterised in that binder is added to the fibrous material prior to dewatering and pressing

Country Status (16)

Country Link
EP (1) EP0663972B1 (en)
AT (1) ATE144299T1 (en)
AU (1) AU665817B2 (en)
CA (1) CA2131525A1 (en)
DE (1) DE69305529T2 (en)
EE (1) EE9400251A (en)
ES (1) ES2093417T3 (en)
FI (1) FI96976C (en)
GR (1) GR3021653T3 (en)
LT (1) LT3163B (en)
LV (1) LV10657B (en)
NO (1) NO301944B1 (en)
NZ (1) NZ251000A (en)
RU (1) RU2080429C1 (en)
SE (1) SE470101B (en)
WO (1) WO1993018227A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1017549A1 (en) * 1997-09-18 2000-07-12 HÜTTENS-ALBERTUS CHEMISCHE WERKE GmbH Method for producing moulded bodies, moulded body and installation for carrying out said method
US7368037B2 (en) 2003-05-21 2008-05-06 Masonite Corporation Refiner steam separation system for reduction of dryer emissions
LT6163B (en) 2013-10-15 2015-06-25 Vilniaus Dailės Akademija Plant fiber panels and their method of manufacture

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU55657A1 (en) 1968-03-11 1969-10-02
US3649396A (en) 1970-01-22 1972-03-14 Motala Verkstad Ab Method of making rigid particle boards or the like
JPS56500968A (en) * 1979-07-31 1981-07-16
SE455001B (en) * 1986-10-03 1988-06-13 Rune Simonson METHOD OF MANUFACTURING PRODUCTS CONTAINING FIBERS

Also Published As

Publication number Publication date
NO301944B1 (en) 1997-12-29
NO943379L (en) 1994-09-12
GR3021653T3 (en) 1997-02-28
ES2093417T3 (en) 1996-12-16
ATE144299T1 (en) 1996-11-15
SE470101B (en) 1993-11-08
LT3163B (en) 1995-02-27
NO943379D0 (en) 1994-09-12
LTIP389A (en) 1994-07-15
DE69305529T2 (en) 1997-02-20
LV10657A (en) 1995-04-20
FI944158A0 (en) 1994-09-09
AU3771593A (en) 1993-10-05
EP0663972B1 (en) 1996-10-16
LV10657B (en) 1995-10-20
WO1993018227A1 (en) 1993-09-16
AU665817B2 (en) 1996-01-18
SE9200784L (en) 1993-09-14
EP0663972A1 (en) 1995-07-26
SE9200784D0 (en) 1992-03-13
RU94040866A (en) 1996-07-10
FI96976B (en) 1996-06-14
RU2080429C1 (en) 1997-05-27
CA2131525A1 (en) 1993-09-16
FI944158L (en) 1994-09-09
EE9400251A (en) 1996-02-15
FI96976C (en) 1996-09-25
DE69305529D1 (en) 1996-11-21

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