CA1073162A - Process for treating mechanical pulps and/or products prepared therefrom - Google Patents
Process for treating mechanical pulps and/or products prepared therefromInfo
- Publication number
- CA1073162A CA1073162A CA234,947A CA234947A CA1073162A CA 1073162 A CA1073162 A CA 1073162A CA 234947 A CA234947 A CA 234947A CA 1073162 A CA1073162 A CA 1073162A
- Authority
- CA
- Canada
- Prior art keywords
- pulp
- buffering agent
- weight
- mechanical
- buffers
- 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
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/38—Conserving the finely-divided cellulosic material
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/20—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing organic materials
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
- D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
- D21B1/14—Disintegrating in mills
- D21B1/16—Disintegrating in mills in the presence of chemical agents
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hematology (AREA)
- Wood Science & Technology (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Epidemiology (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Paper (AREA)
- Absorbent Articles And Supports Therefor (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A mechanical pulp, i.e. a pulp obtained by the mechanical defibration of wood, is treated with a buffer selected from the group consisting of an alkali metal or ammonium salt of phosphoric, carbonic, citric or tartaric acid to a pH of 6-10, whereby, after ageing, the pulp maintains its original hydrofilic property. The amount of buffer added to the pulp is at least 0.2 and preferably 0.5% by weight based on the dry pulp.
A mechanical pulp, i.e. a pulp obtained by the mechanical defibration of wood, is treated with a buffer selected from the group consisting of an alkali metal or ammonium salt of phosphoric, carbonic, citric or tartaric acid to a pH of 6-10, whereby, after ageing, the pulp maintains its original hydrofilic property. The amount of buffer added to the pulp is at least 0.2 and preferably 0.5% by weight based on the dry pulp.
Description
r ~LQ7316~
The instant invention relates to a process for treating mechanical pulps and/or products prepared therefrom.
Mechanical pulp is a general term used for pulp types obtained by mechanical defibration of different wood s~ec~es ~K~ It can be produced by the use of grinding stones or disk refiners, optionally subsequent to a mild chemical treat-ment.
As mechanical pulp is relatively inexpensive to produce compared with cellulose pulps obtained by che~ical digestion of woo~, such pulps have been widely used as raw material for the preparation of news print, magazine papers etc However, as mechanical pulp possesses the undesirable property that ik undergoes "self sizing" on storage, it has previously been necessary to store and transport mechanical pulp in a moist condition, or tc dry the pulp in a special manner, for instance by the so called "flash drying method". As a conse-quence of the "self sizing" mechanical wood pulp will after /ro~oh~ ~c storage exhibit ~Ybff~e~ properties to a more or lesser de-gree, dependent on storage time, resin content, storage condi-tion etc.~ which renders the further treatment difficult when the pulp is to be further processed.
Due to the "self sizing" mechanical pulp has only to a minor degree been utilized for absorption purposes, for ns instance in napkins~ sanitary pads~-~}b~Gh~7 towels and simi-lar products. For such purposes has previously been utilized high ~uality bleached cellulose.
It has been shown that if the resin can be removed from the mechanical pulp such pulp can advantageously be used for the above mentioned purposes, such as disclosed in Norwegian Patent No. 124~193. In accordance with said patent the resin can
The instant invention relates to a process for treating mechanical pulps and/or products prepared therefrom.
Mechanical pulp is a general term used for pulp types obtained by mechanical defibration of different wood s~ec~es ~K~ It can be produced by the use of grinding stones or disk refiners, optionally subsequent to a mild chemical treat-ment.
As mechanical pulp is relatively inexpensive to produce compared with cellulose pulps obtained by che~ical digestion of woo~, such pulps have been widely used as raw material for the preparation of news print, magazine papers etc However, as mechanical pulp possesses the undesirable property that ik undergoes "self sizing" on storage, it has previously been necessary to store and transport mechanical pulp in a moist condition, or tc dry the pulp in a special manner, for instance by the so called "flash drying method". As a conse-quence of the "self sizing" mechanical wood pulp will after /ro~oh~ ~c storage exhibit ~Ybff~e~ properties to a more or lesser de-gree, dependent on storage time, resin content, storage condi-tion etc.~ which renders the further treatment difficult when the pulp is to be further processed.
Due to the "self sizing" mechanical pulp has only to a minor degree been utilized for absorption purposes, for ns instance in napkins~ sanitary pads~-~}b~Gh~7 towels and simi-lar products. For such purposes has previously been utilized high ~uality bleached cellulose.
It has been shown that if the resin can be removed from the mechanical pulp such pulp can advantageously be used for the above mentioned purposes, such as disclosed in Norwegian Patent No. 124~193. In accordance with said patent the resin can
- 2 -` ~733~6Z
be removed from the pulp by extraction with acetone, whereby a product with good absorption properties is obtained. However, an industrial extraction process is a complicated and expensive process requiring large capital investment in extraction appara-tus, recovering apparatus etc. Acetone extraction of mechanical pulp has previously been suggested in order to improve the strength property of the mechanical pulp and in order to facili-tate the wet defibration in the subsequent production process.
(Brandal & ~indheim, Pulp & Paper Mag. Canada 6~ T 431, 1966).
It has surprisingly been found that it is possible to treat mechanical pulp in such manner that after agelng it will retain its original hydrophylic propexty. A mechanical pulp treated in accordance with the instant invention will after storage remain hydrophylic and can thus easily be fiberi~ed during the subsequent process steps. It has further been shown that such pulp is eminently suitable for absorption purposes, even if the new process only to a minor degree influences the resin content of the pulp.
The new process comprises a treatment or impregnation of the mechanical pulp with a buffer, which buffers in a pH
range of 6-10, preferentially in the range 7-9. Suitable buffers are alkali metal salts or ammonium salts of for instance phos-phoric acid, carbonic acid, citric acid and tartaric acid.
The buffer is added to the mechanical pulp, preferentially in the form of an aqueous solution and in an amount corresponding to at least 0.2% by weight, based on the dry weight of the pulp, pre-ferentially 0.5% or more.
Such treatment of the mechanical pulp with an aqueous solution of the buffer is inexpensive and simple to .. . . .
r 107 3~
carry out. The addition can be effected in different stages during the production of the mechanical pulp, depending on the field of use for the product and the existing equipment. The addition can for instance take place during the preparation in the refiner or grinder~ in the white water system of the paper machine, in the size press or by spraying during or after the sheet formation, or by injection in the pulp before this optio-nally is converted to pulp bales. Thus the treatment can be carried out with the e~isting equipment and can thus be accom-10 modated to the existing production plants. By means of the new process one can for instance prepare absorbing materials from mechanical pulps~ which means substantial savings compared to the highly refined cellulose products. From resource and environ-ment point of view the new process represents obvious advan-15 tageous features.
In the following the invention will be explained by means of the examples~ showing the effect obtained by the new treatment.
Different pulp types were treated with the buffer 20 by spraying and submerging the pulp in the buffer solution. The dry matter of the pulps before submerging or spraying with the buffer solution were between 25'~o and 90~/0. After treatment the ~c/One A pulp was dried in a 4~ and flufed (in a Wenneberg-mill).
A part of the thus buffer treated and fluffed pulp was artifi-25 cially aged at 150C in 1 hour, whereafter the pulp was allowed to remain at room temperature in 30-60 minutes before the water absorption o the aged pulp was determined. Water absorption for non-aged pulp and non-treated pulp were also determined.
The determination of the water absorption rate in 30 these tests were carried out by evenly distributing 10 g air-~73~6Z
dried, fluffed pulp in a small basket of metal gauze (dimensions 7 cm x 20 cm x 1 cm) which was placed in a container containing 200 ml water. The time taken from the moment the basket was placed in the container and until the pulp is completely moistened by the water is a measure for the water absorption rate of the pulp.
The obtained results are disclosed in the subse-quent table.
.
~L~739L6Z
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O ~ U ~ 1~ ~1 Lt~ 0~ t`
. Q ~ tn _ O _ U~
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,~
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CO ~ ~ ' ~ In ~ O ~ U~ O
,. ~ O ~ . ~ ,1 CO ~ ~ ~o ~
mu~ _ ~, co _ ~^_ . t`^ CD~
S~ ~ ~ Q~
~ ~ 4~ R ~ a) Ll 4 O ~i Q a) ~ ~1 o ::~
~ ~ ~ 4J ~1 Q
c: ~ ~ a~ ~a o a rl ~n ~, ~o O
~ ~ ~ ~ a -~ Q ru~ ~1 LJ ~ ~) ~I) ~
~ Ou~ a) (a ~ o o ~a ~, (1) o ~ (U >~ ~ O ~ U ~ Q ~ ~ (a ~ Q
lJ ~1~1 O .~ O l O ~.1 O ~ 5-1 O ~1 z;~ ~ ~ Z ~ Z ,~ o æ ~
U U ~ ~1 Z;~
~i ~ r 4~ U O 03 ~ ~ æ z z æ
~ ~I) Q O ~ 3~I~
m P~ ~ ~ ~ ~ ~ ~ N (~I ~
~IL __ _ . ~ ~U ~ ~ .
~ S~ ~ ~
a) = ~ b~ _ ~ = ~ ~r~ = .' a) ~ ~ ~ ra .
~ u ~ u u u a ~ ~ .~ ~ .~ .~ ~ ~
r~ ~ ~ ~
~ ~ = ~ _ O _ ~ = ~ ~ S~ _ ,_, Ql u O u t) V ~' PJ 5~ E~ ~ ~ E~ E~
~ 0~ ~ O O O~
.~ ~ ~U ~ ~ ~ ~ ~ ,~UO
4~ = ~ ~ = o ~ ~ = a~ ~ ~ ~ ~ =
O ~ Q~ ~ S rl S rl ,~ Q, h ~ _ E I Q h R h ta ~) _ O
Z
. ~1 ~ ' ~ ~ n X _ .
-- 6 -- .
~L~'73~GZ
As apparent from the above disclosed results by means of the treatment in accordance wlth the invention a sub~
stantial and significant improved water a~sorption rate is ob-tained compared with non-treated pulp. However, an exception is represented by the borate buffer~ which apparently has a decreas-ing effect on the absorption rate for non-aged pulp, however, af-ter ageing the borate buffer treated pulp shows an improved ab-sorption rate compared with non-treated pulp.
Further it wiil be apparent that pulps treated with the di~erent buffers~ with respect to the water absorption rate hardly is influenced by the artificial ageing~ in that difference of 1 sec. probably is within the error limit for the testing me-thods used.
For comparison it can be mentioned that highly refined cellulose under similar conditions exhibits a water absorption rate in the order of 5 sec..
The mechanical pulps in accordance with the instant invention are thus with respect to water absorption rate compar-able with highly purified cellulose pulps, further as they after ageing maintain their hydrofilic properties, and consequently are easily wet defibri~ed in an optional further process, for instance in a paper mill utilizing mechanical pulp as raw material.
Thus the invention comprises an absorbing agent for taon~o ~75 use in napkins~ sanitary pads~-LY~3~, towels etc~ which are characterized in that the mechanical pulp contains a buffer as disclosed above.
be removed from the pulp by extraction with acetone, whereby a product with good absorption properties is obtained. However, an industrial extraction process is a complicated and expensive process requiring large capital investment in extraction appara-tus, recovering apparatus etc. Acetone extraction of mechanical pulp has previously been suggested in order to improve the strength property of the mechanical pulp and in order to facili-tate the wet defibration in the subsequent production process.
(Brandal & ~indheim, Pulp & Paper Mag. Canada 6~ T 431, 1966).
It has surprisingly been found that it is possible to treat mechanical pulp in such manner that after agelng it will retain its original hydrophylic propexty. A mechanical pulp treated in accordance with the instant invention will after storage remain hydrophylic and can thus easily be fiberi~ed during the subsequent process steps. It has further been shown that such pulp is eminently suitable for absorption purposes, even if the new process only to a minor degree influences the resin content of the pulp.
The new process comprises a treatment or impregnation of the mechanical pulp with a buffer, which buffers in a pH
range of 6-10, preferentially in the range 7-9. Suitable buffers are alkali metal salts or ammonium salts of for instance phos-phoric acid, carbonic acid, citric acid and tartaric acid.
The buffer is added to the mechanical pulp, preferentially in the form of an aqueous solution and in an amount corresponding to at least 0.2% by weight, based on the dry weight of the pulp, pre-ferentially 0.5% or more.
Such treatment of the mechanical pulp with an aqueous solution of the buffer is inexpensive and simple to .. . . .
r 107 3~
carry out. The addition can be effected in different stages during the production of the mechanical pulp, depending on the field of use for the product and the existing equipment. The addition can for instance take place during the preparation in the refiner or grinder~ in the white water system of the paper machine, in the size press or by spraying during or after the sheet formation, or by injection in the pulp before this optio-nally is converted to pulp bales. Thus the treatment can be carried out with the e~isting equipment and can thus be accom-10 modated to the existing production plants. By means of the new process one can for instance prepare absorbing materials from mechanical pulps~ which means substantial savings compared to the highly refined cellulose products. From resource and environ-ment point of view the new process represents obvious advan-15 tageous features.
In the following the invention will be explained by means of the examples~ showing the effect obtained by the new treatment.
Different pulp types were treated with the buffer 20 by spraying and submerging the pulp in the buffer solution. The dry matter of the pulps before submerging or spraying with the buffer solution were between 25'~o and 90~/0. After treatment the ~c/One A pulp was dried in a 4~ and flufed (in a Wenneberg-mill).
A part of the thus buffer treated and fluffed pulp was artifi-25 cially aged at 150C in 1 hour, whereafter the pulp was allowed to remain at room temperature in 30-60 minutes before the water absorption o the aged pulp was determined. Water absorption for non-aged pulp and non-treated pulp were also determined.
The determination of the water absorption rate in 30 these tests were carried out by evenly distributing 10 g air-~73~6Z
dried, fluffed pulp in a small basket of metal gauze (dimensions 7 cm x 20 cm x 1 cm) which was placed in a container containing 200 ml water. The time taken from the moment the basket was placed in the container and until the pulp is completely moistened by the water is a measure for the water absorption rate of the pulp.
The obtained results are disclosed in the subse-quent table.
.
~L~739L6Z
~` ~ o ~ ~ o u~ ~ o ~ ~ O ) O OD n a~ O
O ~ U ~ 1~ ~1 Lt~ 0~ t`
. Q ~ tn _ O _ U~
~ s~' ~
,~
a~
CO ~ ~ ' ~ In ~ O ~ U~ O
,. ~ O ~ . ~ ,1 CO ~ ~ ~o ~
mu~ _ ~, co _ ~^_ . t`^ CD~
S~ ~ ~ Q~
~ ~ 4~ R ~ a) Ll 4 O ~i Q a) ~ ~1 o ::~
~ ~ ~ 4J ~1 Q
c: ~ ~ a~ ~a o a rl ~n ~, ~o O
~ ~ ~ ~ a -~ Q ru~ ~1 LJ ~ ~) ~I) ~
~ Ou~ a) (a ~ o o ~a ~, (1) o ~ (U >~ ~ O ~ U ~ Q ~ ~ (a ~ Q
lJ ~1~1 O .~ O l O ~.1 O ~ 5-1 O ~1 z;~ ~ ~ Z ~ Z ,~ o æ ~
U U ~ ~1 Z;~
~i ~ r 4~ U O 03 ~ ~ æ z z æ
~ ~I) Q O ~ 3~I~
m P~ ~ ~ ~ ~ ~ ~ N (~I ~
~IL __ _ . ~ ~U ~ ~ .
~ S~ ~ ~
a) = ~ b~ _ ~ = ~ ~r~ = .' a) ~ ~ ~ ra .
~ u ~ u u u a ~ ~ .~ ~ .~ .~ ~ ~
r~ ~ ~ ~
~ ~ = ~ _ O _ ~ = ~ ~ S~ _ ,_, Ql u O u t) V ~' PJ 5~ E~ ~ ~ E~ E~
~ 0~ ~ O O O~
.~ ~ ~U ~ ~ ~ ~ ~ ,~UO
4~ = ~ ~ = o ~ ~ = a~ ~ ~ ~ ~ =
O ~ Q~ ~ S rl S rl ,~ Q, h ~ _ E I Q h R h ta ~) _ O
Z
. ~1 ~ ' ~ ~ n X _ .
-- 6 -- .
~L~'73~GZ
As apparent from the above disclosed results by means of the treatment in accordance wlth the invention a sub~
stantial and significant improved water a~sorption rate is ob-tained compared with non-treated pulp. However, an exception is represented by the borate buffer~ which apparently has a decreas-ing effect on the absorption rate for non-aged pulp, however, af-ter ageing the borate buffer treated pulp shows an improved ab-sorption rate compared with non-treated pulp.
Further it wiil be apparent that pulps treated with the di~erent buffers~ with respect to the water absorption rate hardly is influenced by the artificial ageing~ in that difference of 1 sec. probably is within the error limit for the testing me-thods used.
For comparison it can be mentioned that highly refined cellulose under similar conditions exhibits a water absorption rate in the order of 5 sec..
The mechanical pulps in accordance with the instant invention are thus with respect to water absorption rate compar-able with highly purified cellulose pulps, further as they after ageing maintain their hydrofilic properties, and consequently are easily wet defibri~ed in an optional further process, for instance in a paper mill utilizing mechanical pulp as raw material.
Thus the invention comprises an absorbing agent for taon~o ~75 use in napkins~ sanitary pads~-LY~3~, towels etc~ which are characterized in that the mechanical pulp contains a buffer as disclosed above.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A mechanical pulp which is easily wet defiberized and exhibits a high water absorption rate which contains at least 0.2% by weight of a buffering agent other than borate, which buffers in the pH range 6-10 based on the weight of dry pulp.
2. A pulp as claimed in claim 1 in which the buffering agent buffers in the pH range 7 to 9.
3. A pulp in accordance with claim 1, 2 or 3 which contains as buffering agent an alkali metal salt or ammonium salt of phosphoric acid, carbonic acid, citric acid or tartaric acid or mixtures thereof.
4. A pulp as claimed in claim 1 or 2 which contains at least 0.5% by weight of buffering agent based on dry pulp
5. A pulp as claimed in claim 1 or 2 in which the buffering agent is sodium phosphate citrate or carbonate or ammonium carbonate.
6. A process for the preparation of a mechanical pulp which comprises adding to the pulp at least 0.2% by weight of a buffering agent other than borate which buffers in the pH range of 6-10 based On the weight of dry pulp.
7. A process as claimed in claim 6 in which the buffering agent buffers in the pH range 7 to 9.
8. A process in accordance with claim 6 or 7 in which the buffering agent is an alkali metal or ammonium salt of phosphoric acid, carbonic acid, citric acid or tartaric acid or mixtures thereof.
9. A process in accordance with claim 6 or 7 in which the buffering agent is added to the pulp in an amount of at least 0.5% by weight based on the dry pulp.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO743286A NO136583C (en) | 1974-09-12 | 1974-09-12 | MECHANICAL TRIMASSES WITH HIGH SPEED OF ABSORPTION, AND PROCEDURE FOR PREPARING THEREOF |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073162A true CA1073162A (en) | 1980-03-11 |
Family
ID=19881821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA234,947A Expired CA1073162A (en) | 1974-09-12 | 1975-09-08 | Process for treating mechanical pulps and/or products prepared therefrom |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS5184904A (en) |
| AT (1) | AT347781B (en) |
| BE (1) | BE833343A (en) |
| CA (1) | CA1073162A (en) |
| DE (1) | DE2539570C3 (en) |
| DK (1) | DK141255B (en) |
| FI (1) | FI59444C (en) |
| FR (1) | FR2284706A1 (en) |
| GB (1) | GB1515865A (en) |
| IT (1) | IT1049168B (en) |
| NL (1) | NL7510763A (en) |
| NO (1) | NO136583C (en) |
| SE (1) | SE418873B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE432118B (en) * | 1975-02-26 | 1984-03-19 | Moelnlycke Ab | MECHANICAL FLUFF MASS AND SET FOR PREPARATION THEREOF |
| NO760666L (en) * | 1976-02-27 | 1977-08-30 | Papirind Forskningsinst | PROCEDURE FOR MAKING MECHANICAL MASSES. |
| PH13425A (en) * | 1976-05-10 | 1980-04-23 | Du Pont | 2,3,8,12b-tetrahydro 1 h-3a,8-methano-dibenzo(3,4,6,7)cyclohepta(1,2-c)pyrrole derivatives pharmaceutical compositions containing same and method |
| DE3128100C2 (en) * | 1981-07-16 | 1986-05-22 | Chemische Fabrik Stockhausen GmbH, 4150 Krefeld | Absorbents for blood and serous body fluids |
| DE3712445A1 (en) * | 1987-04-11 | 1988-10-20 | Ver Papierwerke Ag | HYGIENIC PULP PRODUCT WITH IMPROVED SKIN COMPATIBILITY |
-
1974
- 1974-09-12 NO NO743286A patent/NO136583C/en unknown
-
1975
- 1975-09-05 DE DE2539570A patent/DE2539570C3/en not_active Expired
- 1975-09-05 AT AT688175A patent/AT347781B/en active
- 1975-09-08 CA CA234,947A patent/CA1073162A/en not_active Expired
- 1975-09-10 FR FR7527764A patent/FR2284706A1/en active Granted
- 1975-09-10 IT IT12785/75A patent/IT1049168B/en active
- 1975-09-11 DK DK406775AA patent/DK141255B/en not_active Application Discontinuation
- 1975-09-11 FI FI752552A patent/FI59444C/en not_active IP Right Cessation
- 1975-09-11 SE SE7510158A patent/SE418873B/en not_active Application Discontinuation
- 1975-09-12 NL NL7510763A patent/NL7510763A/en not_active Application Discontinuation
- 1975-09-12 BE BE159977A patent/BE833343A/en not_active IP Right Cessation
- 1975-09-12 JP JP50110115A patent/JPS5184904A/ja active Pending
- 1975-09-12 GB GB37605/75A patent/GB1515865A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2539570C3 (en) | 1980-02-14 |
| NO136583C (en) | 1984-06-07 |
| SE418873B (en) | 1981-06-29 |
| ATA688175A (en) | 1978-05-15 |
| DE2539570B2 (en) | 1979-06-13 |
| DE2539570A1 (en) | 1976-04-01 |
| NO136583B (en) | 1977-06-20 |
| JPS5184904A (en) | 1976-07-24 |
| AT347781B (en) | 1979-01-10 |
| FI59444C (en) | 1981-08-10 |
| AU8455175A (en) | 1977-03-10 |
| NL7510763A (en) | 1976-03-16 |
| FR2284706B1 (en) | 1982-04-23 |
| BE833343A (en) | 1975-12-31 |
| NO743286L (en) | 1976-03-15 |
| SE7510158L (en) | 1976-03-15 |
| FI59444B (en) | 1981-04-30 |
| FR2284706A1 (en) | 1976-04-09 |
| DK406775A (en) | 1976-03-13 |
| IT1049168B (en) | 1981-01-20 |
| GB1515865A (en) | 1978-06-28 |
| FI752552A (en) | 1976-03-13 |
| DK141255B (en) | 1980-02-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |