CA1134213A - Process for the production of flame proof cellulosic material - Google Patents
Process for the production of flame proof cellulosic materialInfo
- Publication number
- CA1134213A CA1134213A CA316,418A CA316418A CA1134213A CA 1134213 A CA1134213 A CA 1134213A CA 316418 A CA316418 A CA 316418A CA 1134213 A CA1134213 A CA 1134213A
- Authority
- CA
- Canada
- Prior art keywords
- flame
- drying
- cellulosic material
- proof
- cellulosic
- 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
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
- D21C9/185—De-watering; Elimination of cooking or pulp-treating liquors from the pulp comprising at least one step where the pulp is suspended in a gaseous medium, e.g. flash drying
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Paper (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
- Fireproofing Substances (AREA)
Abstract
CANADIAN PATENT APPLICATION
OF
MATS-OLOV HEDBLOM
AND
ZOJA LINDH-N?MM
FOR
A PROCESS FOR THE PRODUCTION OF
FLAME-PROOF CELLULOSIC MATERIAL
Abstract of the Disclosure The invention relates to a process for the production of a fibrous flame-proof cellulosic material, in which process an aqueous cellulosic material is impregnated with a flame-proofing chemical which is dissolved or suspended in water, whereupon the material impregnated in this manner is comminuted and then subjected to drying and, optionally, curing in a system which includes a hot gas stream and in which the cellulosic fibers are present in essentially detached form.
OF
MATS-OLOV HEDBLOM
AND
ZOJA LINDH-N?MM
FOR
A PROCESS FOR THE PRODUCTION OF
FLAME-PROOF CELLULOSIC MATERIAL
Abstract of the Disclosure The invention relates to a process for the production of a fibrous flame-proof cellulosic material, in which process an aqueous cellulosic material is impregnated with a flame-proofing chemical which is dissolved or suspended in water, whereupon the material impregnated in this manner is comminuted and then subjected to drying and, optionally, curing in a system which includes a hot gas stream and in which the cellulosic fibers are present in essentially detached form.
Description
~l3~2~3 The invention relates to a novel process of making materials of cellulosic ~ib~rs flame-proof- In particular, the invention relates to the use of a special drying technique for imparting improved temporary or permanent flame-proofneSS
to cellulosic materials.
In the context of the invention, the term "cellulosic materials" comprises àll types of pulps, from groundwood pulp to ~-cellulose.
The term "permanently flame-proof" implies that the material after soaking in excess water for at least 3 h and subsequent drying does not, when exposed to the flame of a bunsen burner, sustain the flame or permit any undesired afterglow. The term "temporarily flame-proof~' implies that the material, when subjected to leaching, loses its flame ~roofness and does not satisfy the requirement of permanent flame-proofness.
Known methods of making cellulosic materials flame-proof are based on the principle that finished and dried products are impregnated in a separate step with a flame-proofing chemical and dried again. However, because of such factors as the shape, density, surface finish etc. of the products, it is extremely difficult and in some cases prac-tically impossible to achieve a sufficiently uniform distri-bution of the flame-proofing chemical within the product. For similar reasons, also the subsequent drying is frequently a matter of considerable-di`fficulty.
One object of the present invention is to provide a flame-Proof cellulosic material in which the flame-proofing JB/bs 2 ~3~2~3 chemical is uniformly distributed.
A further object of this invention is to Provide a fla~proo cellulosic material which according to requirement can be made permanently or temporarily flame-proof by means of a simplified process where the impregnation step comes ~efore the drying of the cellulosic material, which must be effected regardless of whether or not the material is to be rendered flame-proof. In other words, the step of render-ing the material ~ame-proof is an integral part of the pro-duction of the cellulosic material which then is shaped in different ways, depending upon the contemplated final use.
This implies that, contrary to prior art technique, one drying step can be eliminated entirely.
According to the invention, these advantages are achieved by impregnating a preferably aqueous cellulosic material with a flame-proofing chemical which is dissolved or suspended in water, and comminuting the impregnated material r for instance by shredding, and optionally fluffing it, whereupon the resulting material is subjected to drying and,optionally,to curing in a system comprising a hot, preferably t~ ulent gas stream-by which the cellulosic material at the same time is conveyed within the drying (and curing) system.
The impregnation with the flame-proofing chemical may be effected ln known manner, it being essential that the chemical is uniformly distributed within the cellulosic ma-terial. To in_rease the penetration ability of the impreg-natlng agent, surfactants may be added. The impregnating agent, i.e. the flame-proofing chemical or a combination of , .. : :. ,: .
:...... . .::
~3~2~3 several different such chemicals, is dissolved or suspended in water. The invention is not restricted to any specific type of flame-proofing chemical, although of course one should select such chemicals as do not cause functional trouble at the drying or curing temperature, or environmental pollution.
Examples of suitable flame-proofing chemicals are phosphoric acids, amidophosphoric acids, ammonium phosphates, ammonium sulphates, ammonium sulphamates, ammonium amidophosphates, ammonium amidopolyphosphates, ammonium polyphosphates, boric acid, sodium borates, aluminium hydroxide, ammonium ch~oride, ammonium bromide, potassium aluminium sulphate, antimony oxide in combination with halogen, phosphates or phosphoric acid in combination with urea. The concentration of the flame-proofing chemical must be sufficient to be able to provide a flame-proof material, and the active amount of the flame-proofing chemical usually amounts to about 5-60~ by weight, based upon the dry weight.
Before the soaked or impregnated material enters the drying system, it must be subjected to mechanical commlnution, such as shredding and, optionally, fluffing so that it will be present in a form suitable for the subsequent treatment in the drying system.
The impregnated cellulosic material, comminuted to a suitable degree of fineness, is then introduced into the drying system where it encounters a hot gas stream of a velocity exceeding that of the suspended material. The gas flow within the drying system preferably is turbulent, and the fibers of the cellulosic~material should be essentially .
39~2~3 detached. To be able to control the drying and the curing, if any, heating means, such as oil burners, should be pro-vided at one or more locations within the drying system, and furthermore the steam formed during the heating of the cellu-losic fibrous material should be removed, preferably in cyclone type separators. By providing in this manner, one or more drying devices and one or more separators within the drying system, it is possible effectively to control the drying (curing) temperature of the cellulosic fibrous material and to adapt the drying (curing) operation to the cellulosic starting material, the flame-proofing chemical and the desired final use of the resulting product. The hot gas employed for the drying (or curing) preferably is air.
A type of drying device operating on these principles is the so-called flash drier which is normally used for drying pulps of different types and never has been used before for the drying of flame-proofed cellulosic material.
The drying process of the present invention gives a com-bination of the flame-proofing agent and the cellulosic fiber, and one obtains a fibrous cellulosic material which is flame-proof, a~though not permanently, and which is entirely satisfac-tory for many uses. If, however, it is desired to produce a material which is permanently flame-proof, certain flame-proofing agents are employed, such as phosphoric acid or am-monium phosphates in combination with urea or ammonium salts of amidophosphoric acids or amidopolyphosphoric acids, pos-sibly in combination with urea. In that case, one operates at a further increased temperature in a curing step integral with the final phase of the drying step, in order to produce
to cellulosic materials.
In the context of the invention, the term "cellulosic materials" comprises àll types of pulps, from groundwood pulp to ~-cellulose.
The term "permanently flame-proof" implies that the material after soaking in excess water for at least 3 h and subsequent drying does not, when exposed to the flame of a bunsen burner, sustain the flame or permit any undesired afterglow. The term "temporarily flame-proof~' implies that the material, when subjected to leaching, loses its flame ~roofness and does not satisfy the requirement of permanent flame-proofness.
Known methods of making cellulosic materials flame-proof are based on the principle that finished and dried products are impregnated in a separate step with a flame-proofing chemical and dried again. However, because of such factors as the shape, density, surface finish etc. of the products, it is extremely difficult and in some cases prac-tically impossible to achieve a sufficiently uniform distri-bution of the flame-proofing chemical within the product. For similar reasons, also the subsequent drying is frequently a matter of considerable-di`fficulty.
One object of the present invention is to provide a flame-Proof cellulosic material in which the flame-proofing JB/bs 2 ~3~2~3 chemical is uniformly distributed.
A further object of this invention is to Provide a fla~proo cellulosic material which according to requirement can be made permanently or temporarily flame-proof by means of a simplified process where the impregnation step comes ~efore the drying of the cellulosic material, which must be effected regardless of whether or not the material is to be rendered flame-proof. In other words, the step of render-ing the material ~ame-proof is an integral part of the pro-duction of the cellulosic material which then is shaped in different ways, depending upon the contemplated final use.
This implies that, contrary to prior art technique, one drying step can be eliminated entirely.
According to the invention, these advantages are achieved by impregnating a preferably aqueous cellulosic material with a flame-proofing chemical which is dissolved or suspended in water, and comminuting the impregnated material r for instance by shredding, and optionally fluffing it, whereupon the resulting material is subjected to drying and,optionally,to curing in a system comprising a hot, preferably t~ ulent gas stream-by which the cellulosic material at the same time is conveyed within the drying (and curing) system.
The impregnation with the flame-proofing chemical may be effected ln known manner, it being essential that the chemical is uniformly distributed within the cellulosic ma-terial. To in_rease the penetration ability of the impreg-natlng agent, surfactants may be added. The impregnating agent, i.e. the flame-proofing chemical or a combination of , .. : :. ,: .
:...... . .::
~3~2~3 several different such chemicals, is dissolved or suspended in water. The invention is not restricted to any specific type of flame-proofing chemical, although of course one should select such chemicals as do not cause functional trouble at the drying or curing temperature, or environmental pollution.
Examples of suitable flame-proofing chemicals are phosphoric acids, amidophosphoric acids, ammonium phosphates, ammonium sulphates, ammonium sulphamates, ammonium amidophosphates, ammonium amidopolyphosphates, ammonium polyphosphates, boric acid, sodium borates, aluminium hydroxide, ammonium ch~oride, ammonium bromide, potassium aluminium sulphate, antimony oxide in combination with halogen, phosphates or phosphoric acid in combination with urea. The concentration of the flame-proofing chemical must be sufficient to be able to provide a flame-proof material, and the active amount of the flame-proofing chemical usually amounts to about 5-60~ by weight, based upon the dry weight.
Before the soaked or impregnated material enters the drying system, it must be subjected to mechanical commlnution, such as shredding and, optionally, fluffing so that it will be present in a form suitable for the subsequent treatment in the drying system.
The impregnated cellulosic material, comminuted to a suitable degree of fineness, is then introduced into the drying system where it encounters a hot gas stream of a velocity exceeding that of the suspended material. The gas flow within the drying system preferably is turbulent, and the fibers of the cellulosic~material should be essentially .
39~2~3 detached. To be able to control the drying and the curing, if any, heating means, such as oil burners, should be pro-vided at one or more locations within the drying system, and furthermore the steam formed during the heating of the cellu-losic fibrous material should be removed, preferably in cyclone type separators. By providing in this manner, one or more drying devices and one or more separators within the drying system, it is possible effectively to control the drying (curing) temperature of the cellulosic fibrous material and to adapt the drying (curing) operation to the cellulosic starting material, the flame-proofing chemical and the desired final use of the resulting product. The hot gas employed for the drying (or curing) preferably is air.
A type of drying device operating on these principles is the so-called flash drier which is normally used for drying pulps of different types and never has been used before for the drying of flame-proofed cellulosic material.
The drying process of the present invention gives a com-bination of the flame-proofing agent and the cellulosic fiber, and one obtains a fibrous cellulosic material which is flame-proof, a~though not permanently, and which is entirely satisfac-tory for many uses. If, however, it is desired to produce a material which is permanently flame-proof, certain flame-proofing agents are employed, such as phosphoric acid or am-monium phosphates in combination with urea or ammonium salts of amidophosphoric acids or amidopolyphosphoric acids, pos-sibly in combination with urea. In that case, one operates at a further increased temperature in a curing step integral with the final phase of the drying step, in order to produce
2~3 a reaction (i.e. a curing) between the fibers and the flame proofing agent. Naturally, the temperatures during the drying and the curing, if any, as well as during the residence time in the drying (curing) system vary in dependence upon the cellulosic starting material employed, the flame-proofing chemical and the desired final product and can be established in each individual case by a simple trial run.
In order to point out more fully the nature of the present invention, the following specific Examples are given.
A flash drier comprising three drying steps was sup~lied in conventional manner with a web of fully bleached kraft pulp for drying. After the dewatering presses, but before the coarse and fine shredding steps, the pulp was impregnated by spraying with about 25~, based on the dry weight of the pulp (and the solution), of a 50~ solution of ammonium polyphosphate.
About 1 min after the addition of the flame-proofing agent, a flame-proof sample was taken of the discharged dry pulp. No anomalies in the production process were observed.
The same procedure as in Examole 1, although about 15%
of the flame-proofing agent were added.
The discharged pulp exhibited satisfactory flame proof-ness.
The same procedure as in Example 1, although about 20%
(based on the dry pulp) of ammonium suIphamate were added.
The discharged pulp sxhibited satisfactory flame proof-ness.
, . ' ' . ~ ` ` .` . ' . : . ` : ` ` ~, ` ~' .: ,:
~3~2~;3 70 parts of finely divided boric acid and 20 parts offinely divided borax were added under intense agitation to a dissolver containing 60 parts of water. The mixture was heated to about 60C for 2 h, and the major part of the added powder was dissolved.
In the same manner as in Example 1, the mixture was added to an amount of 20% (dry weight) based on the dry pulp.
Pulp samples taken exhibited satisfactory flame-proof-ness.
An anhydrous reaction product of NH3-P2O5 (prepared by burning elemental phosphorus with dry air to produce essen-tially gaseous P2O5 which immediately was caused to react with excess NH3 in relation to the amount reacting with P2O5, and separation of the reaction product in the form of a white powder) containing about 6.5% amide nitrogen was dissolved in water to a concentration of 50%, whereupon the pH was adjusted to about 6.5, ammonium hydroxide solution being added. In the same manner as in Example 1, the solution was added to an amount of 20% (dry weight) based on the dry pulp.
The pulp samples taken showed excellent flame-proofness.
The same procedure as in Example 5, although the tem-peratures in the three drying steps of the flash drier were increased beyond the normal values. Under the same conditions as before, the following gas output temperatures in the differ-ent drying steps were measured:
2~
Drying step 1 about 100C
.Drying step 2 about 140C
Drying step 3 .about 180 C
The discharged pulp exhibited permanent flame-proofness characteristics.
:: . : .. .. ; ., . ,. :
- . . : ~
: : : ~,, ,. . : ; .:
In order to point out more fully the nature of the present invention, the following specific Examples are given.
A flash drier comprising three drying steps was sup~lied in conventional manner with a web of fully bleached kraft pulp for drying. After the dewatering presses, but before the coarse and fine shredding steps, the pulp was impregnated by spraying with about 25~, based on the dry weight of the pulp (and the solution), of a 50~ solution of ammonium polyphosphate.
About 1 min after the addition of the flame-proofing agent, a flame-proof sample was taken of the discharged dry pulp. No anomalies in the production process were observed.
The same procedure as in Examole 1, although about 15%
of the flame-proofing agent were added.
The discharged pulp exhibited satisfactory flame proof-ness.
The same procedure as in Example 1, although about 20%
(based on the dry pulp) of ammonium suIphamate were added.
The discharged pulp sxhibited satisfactory flame proof-ness.
, . ' ' . ~ ` ` .` . ' . : . ` : ` ` ~, ` ~' .: ,:
~3~2~;3 70 parts of finely divided boric acid and 20 parts offinely divided borax were added under intense agitation to a dissolver containing 60 parts of water. The mixture was heated to about 60C for 2 h, and the major part of the added powder was dissolved.
In the same manner as in Example 1, the mixture was added to an amount of 20% (dry weight) based on the dry pulp.
Pulp samples taken exhibited satisfactory flame-proof-ness.
An anhydrous reaction product of NH3-P2O5 (prepared by burning elemental phosphorus with dry air to produce essen-tially gaseous P2O5 which immediately was caused to react with excess NH3 in relation to the amount reacting with P2O5, and separation of the reaction product in the form of a white powder) containing about 6.5% amide nitrogen was dissolved in water to a concentration of 50%, whereupon the pH was adjusted to about 6.5, ammonium hydroxide solution being added. In the same manner as in Example 1, the solution was added to an amount of 20% (dry weight) based on the dry pulp.
The pulp samples taken showed excellent flame-proofness.
The same procedure as in Example 5, although the tem-peratures in the three drying steps of the flash drier were increased beyond the normal values. Under the same conditions as before, the following gas output temperatures in the differ-ent drying steps were measured:
2~
Drying step 1 about 100C
.Drying step 2 about 140C
Drying step 3 .about 180 C
The discharged pulp exhibited permanent flame-proofness characteristics.
:: . : .. .. ; ., . ,. :
- . . : ~
: : : ~,, ,. . : ; .:
Claims (5)
1. A process for producing a fibrous, flame-proof cellulosic material, comprising impregnating an aqueous cellu-losic material with a flame-proofing chemical suspended in water, comminuting the impregnated material by shredding and flutting, subjecting the resulting material to drying and curing in a system including conveying the cellulosic material in a hot turbulent gas stream within the system,
2. The process as claimed in claim 1, including separating steam generated in the system from the cellulosic material and removing the steam from the system.
3. The process as claimed in claim 1 or claim 2, including supplying the system with heat by direct conduction at at least one location.
4. The process as claimed in claim 1 or claim 2, wherein the cellulosic material is in the form of essentially detached fibers within the system.
5. The process as claimed in claim 1 or claim 2, wherein the drying is effected in a flash drier.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7713497A SE420432B (en) | 1977-11-29 | 1977-11-29 | PROCEDURE FOR MANUFACTURING FLAMFAST PAPER MATERIAL |
| SE7713497-1 | 1977-11-29 | ||
| SE7811348-7 | 1978-11-02 | ||
| SE7811348A SE423728B (en) | 1977-11-29 | 1978-11-02 | PROCEDURE FOR MANUFACTURING FLAMFAST CELLULO MATERIAL |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1134213A true CA1134213A (en) | 1982-10-26 |
Family
ID=26656919
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA316,418A Expired CA1134213A (en) | 1977-11-29 | 1978-11-17 | Process for the production of flame proof cellulosic material |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5493078A (en) |
| CA (1) | CA1134213A (en) |
| DE (1) | DE2850496C2 (en) |
| FI (1) | FI68099C (en) |
| FR (1) | FR2410016B1 (en) |
| GB (1) | GB2010940B (en) |
| NO (1) | NO153065C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5282932A (en) * | 1992-10-19 | 1994-02-01 | Canadian Liquid Air Ltd./Air Liquide Canada Ltee | Process for pH and fire control in pulp balers |
| DE202011102812U1 (en) * | 2011-06-14 | 2011-12-05 | Hachemie Hamburger Chemikalien-Gesellschaft Mbh | Thermal insulation material from recycled paper with flame retardant composition |
-
1978
- 1978-11-17 CA CA316,418A patent/CA1134213A/en not_active Expired
- 1978-11-21 DE DE2850496A patent/DE2850496C2/en not_active Expired
- 1978-11-23 NO NO783951A patent/NO153065C/en unknown
- 1978-11-27 JP JP14541578A patent/JPS5493078A/en active Pending
- 1978-11-28 GB GB7846275A patent/GB2010940B/en not_active Expired
- 1978-11-28 FI FI783637A patent/FI68099C/en not_active IP Right Cessation
- 1978-11-29 FR FR787833721A patent/FR2410016B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2010940A (en) | 1979-07-04 |
| JPS5493078A (en) | 1979-07-23 |
| NO153065C (en) | 1986-01-08 |
| NO153065B (en) | 1985-09-30 |
| DE2850496A1 (en) | 1979-05-31 |
| FI68099C (en) | 1985-07-10 |
| DE2850496C2 (en) | 1982-07-01 |
| FI783637A (en) | 1979-05-30 |
| FR2410016B1 (en) | 1985-07-26 |
| FI68099B (en) | 1985-03-29 |
| FR2410016A1 (en) | 1979-06-22 |
| NO783951L (en) | 1979-05-30 |
| GB2010940B (en) | 1982-06-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |