Manufacture of Waterproof Paper, Pasteboard, Millboard, and the like, and the Production of Compounds therefor
Year: 1896

page_text: Date of Application, 28th Dec., 1896
Complete Specification Left, 27th Sept., 1897-Accepted, 24th Dec., 1897
ONAL SPECIT
"Manufacture of Waterproof Paper, Pasteboard, Millboard, and the
like, and the Production of Compounds therefor."
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer, and Chartered Patent Agent, do
hereby declare the nature of this invention to be as follows:-
The dark coloured waste lyes from sulphite cellulose factories, which lies smell
of sulphorous acid and have a neutral reaction, contain as essential constituent the
lime compound of one or more organic substances of an acid character, together
with sulphite or acid sulphite of lime. If the lye is mixed with solutions of salts
of protoxide or oxide of iron, or of lead, preferably in quantities equivalent to
the lime percentage, liquids are obtained which are particularly suited for the
manufacture of water-proof fabrics of various kinds.
A paper material saturated with one of these solutions of suitable concentration,
however only receives after treatment in a dry heat, the property of being impornie-
able to water.
A temperature of from 70 to 80° C is sufficient for this purpose. When using
temperatures above 100° C a limit is reached, dependent upon the properties of the
paper material, which must not be detrimentally affected thereby (such as becom-
ing brittle).
The darkly tinted paper, in particular when using dark lyes, can, if necessary
be washed in water without losing its waterproof character, until it has assumed
a lighter tint, and no longer gives off colouring constituents to the washing water
(which constituents appear to consist of the iron compound of a tannin-like sub-
stance) whereupon it is submitted to a drying operation.
Lead salts are less suitable than iron salts on account of their poisonous nature
and the tendency of the paper to darken subsequently.
The impregnating liquids prepared as above, contain according to the heavy
metal salts chosen other salts having no action (such as calcium chloride, if chloride
of iron was taken). This may be avoided by, the use of sulphate salts or by the
addition of a quantity of sulphuric acid equivalent to the lime, filtering off the
separated gypsum, and dissolving the hydrated iron oxide sludge in the filtrate
whereby solutions can be obtained that are free from such above named salts.
The process can also be modified in such a way, that first-all lime is precipitated,
by carbonate of soda ammonia, or the-like, and then the lime precipitate is filtered
off, and the necessary quantity of iron salt is added to the filtrate.
EXAMPLE I.
100 cub. cm. of ordinary unconcentrated waste lye of sulphite cellulose, smelling
of sulphurous acid and having about 083 grammes of lime (CaO) are mixed with
aqueous solutions of 2 grammes of chloride of iron of 66 pc., or 4 grammes of
crystallised sulphate of iron, and the mixture is then neutralised by addition of

page_text: For the production of concentrated solutions the mass is subject to partial
evaporation, preferably before the neutralisation, whereby a portion of the sulphur-
ous acid is directly removed.
The said alkaline reacting substances can also be first added, the addition of the
iron solution then being effected after the filtering.
Unsized paper saturated with one of these liquids and then dried and heated for
a certain time to 80° to 130° C will be found to be impervious to water.
EXAMPLE II.
100 cube cm. of the waste lye of sulphite mentioned in example I are mixed
with dilute sulphuric acid containing 1'45 grammes of H.SO.
In this solution is suspended a washed iron oxide or protoxide sludge precipi-
tated from about 3 to 4 grammes of sesquichloride of iron. or from about 5 to 6
grammes of sulphate of iron by means of suitable alkaline reacting substances,
until the smell of sulphurous acid has disappeared:. The reaction can be acceler-
ated by heating. If the solution still shews a weak acid reaction, more alkali is
added and the mass is filtered.
EXAMPLE III.
100 parts by weight of concentrated 'black coloured neutral waste lye of sulphite
cellulose, of 34-350 Be that does not smell of sulphurous acid; (about 53 p.c. dry
residue with 4'4 p.c. CaO), are diluted with so much water that the carbonate, of
line, separated by the addition of a solution of 9 parts-calcined-carbonate of
soda, is still deposited when allowed to stand, whereupon thero is added to the
decanted liquid a solution of 30 parts of crystallised acetate of lead.
The mixture of these two solutions is not to be heated because a precipitate would
in this case be formed.
It can however be stored for a long time for use, at ordinary temperature.
Dated this 28th day of December 1896.
ABEL & IMRAY,
Agents for the Applicant.
"Manufacture of Waterproof Paper, Pasteboard, Millboard, and the
like, and the Production of Compounds therefor."
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer, and Chartered Patent Agent,, do.
hereby declare the nature of this invention (which has been communicated to me
from abroad by Farbwerk Friedrichsfeld Dr. Paul Remy, in Mannheim, Baden,
Germany) and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The dark coloured waste lyes from sulphite cellulose factories, which lyes' smell
of sulphurous acid and have a neutral reaction contain as essential constituent the
lime compound of one or more organic substances of an acid character, together
with sulphite or acid sulphite of lime. If the lye is mixed with solutions of salts
of protoxide or oxide of iron, or mixtures of these salts or of (salts of) lead, prefer-
ably in quantities equivalent to the lime percentage, liquids are obtained which
are particularly suited for the manufacture of waterproof paper, pasteboard, mill-.
board, and the like.

page_text: These liquids are moreover suitable for sizing inferior papers their cheapness
commending them for that purpose.
A paper material saturated with one of these solutions of suitable concentration,
however only receives after treatment in a dry heat, the property of being imperme-
able to water.
A temperature of from 70 to 80° C is sufficient for this purpose. When using
temperatures above 100° C a limit is reached, dependent upon the properties of the
paper material, which must not be detrimentally affected thereby (such as beconi-
ing brittle).
The darkly tinted paper in particular when using dark lyes, can, if necessary
be washed in water without losing its waterproof character, until it has assumed
a lighter tint, and no longer gives off colouring constitutents to the washing water
(which constituents appear to consist of the iron compound of a taunin-like sub-
stance) whereupon it is submitted to a drying operation.
Lead salts are less suitable than iron salts on account of their poisonous nature
and the tendency of the paper to darken subsequently.
The impregnating liquids prepared as above, contain according to the heavy
metal salts chosen other salts having no action (such as calcium chloride, if chloride'
or iron was taken). "This may be avoided by the use of sulphate salts or by the
addition of a quantity of sulphuric acid equivalent to the fime; filtering off the
separated gypsum, and dissolving the hydrated iron oxide sludge in the filtrate.
whereby solutions can be obtained that are free from such above named salts.
The process can also be modified in such a way, that first all lime is precipitated
by carbonate of soda ammonia, or the like, and then the lime precipitate is filtered
off, and the necessary quantity of iron salt is added to the filtrate..
EXAMPLE I.
100 cube c.m. of ordinary unconcentrated waste lye of sulphite cellulose, smelling
of sulphurous acid and having about 0.83 grammes of lime (CaO) are mixed with
aqueous solutions of 24 grammes of perchloride of iron of 66 p.c., or 4 grammes
of crystallised sulphate of iron, and the mixture is then neutralised by addition
of some lye, soda solution, ammonia, milk or lime,, or the like.
'
For the production of concentrated solutions the mass is subjected to partial
evaporation, preferably before the neutralisation, whereby a portion of the sulphu-
rous acid is directly removed.
The said alkaline reacting substances can also be first added, the addition of the
iron solution then being affected after the filtering.
EXAMPLE II.
100 cube c.m. of the waste lye of sulphite mentioned in example I are mixed
with dilute sulphuric acid containing 1'45 grammes of ISO.
In this solution is suspended a washed iron oxide or protoxide sludge precipi-
tated from about 3 to 4 grammes of sesquichloride of iron or from about 5 to 6.
grammes of sulphate of iron by means of suitable alkaline reacting substances,
until the smell of sulphurous acid has disappeared. The reaction can be acceler-
ated by heating. If the solution still shews a weak acid reaction, more alkali is
added and the mass is filtered.
The following will serve as an example of the method of practically carrying
out the examples I and II.
In an open cast iron pan which is advantageously coated with lead and provided
with a stirring apparatus, the usual waste sulphite lye, which smells of sulphurous
acid, is heated to 80° or at most 100° C. A neutralisation by means of lime or
chalk sludge is then effected, until lithmus paper is no longer redened. A deposit
is rapidly formed consisting of sulphite of lime, and the clear solution can be
decanted from the deposit. The solution is then mixed with a soluble protoxide
or oxide of iron-salt, in proportion to its percentage of lime. For this purpose
"

page_text: ferrous sulphate or perchloride of iron is taken. After separation of the gypsum
the liquid is separated therefrom by decantation.
1000 litres of waste sulphite lye of 5'5° Bé require about 63 kilos chalk sludge
for neutralisation.
There result about 810 litres of clear lime salt solution.
An addition of 53 litres of ferrous sulphate solution containing about 23 kilos
of ferrous sulphate will precipitate the gypsum, giving 850 litres of finished
impregnating liquid of 6° Be. If commercial perchloride of iron, containing
66 p.c. of Fe Cl, be taken, a quantity hereof equivalent to the preceding quantity
of ferrous sulphate is used; the second decantation or filtering is in this case done
away with, as no gypsum is formed that requires to be removed. When using this
material also lighter tints are produced on the impregnated paper.
When using ferrous sulphate such lighter tints can be obtained by the addition
of acetic acid to the water in which the paper is rinsed.
EXAMPLE III.
100 parts by weight of concentrated-black coloured neutral waste lye of sulphite
cellulose, of 34 to 35° Be that does not smell of sulphurous acid, (about 53. p.c. dry
residue with 4'4 p.c. CaO) are diluted with so much water that the carbonate of
lime, separated by the addition of a solution of 9 parts calcined carbonate of soda,
is still deposited when allowed to. stand, whereupon there is added to the decanted
liquid a solution of 30 parts of crystallised acetate of lead.
The mixture of these two solutions is not to be heated because a precipitate would
in this case be formed.
It can however be stored for a long time for use, at ordinary temperature..
Unsized paper saturated with one of these liquids and then dried and heated for
from 4 to 2 hours at a temperature of from 80° to 130° C. will be found to be
impervious to water.
Having now particularly described and ascertained the nature of this in-
vention, and in what manner the same is to be performed, I declare that what
claim is:
1. The production of compounds for treatment of paper pasteboard, millboard
and the like, by combining ferrous or ferric oxide or mixtures of these, or lead
oxide, with the waste lyes from sulphite cellulose factories, substantially as
described.
2. The manufacture of waterproof paper, pasteboard, millboard, and the like by
saturating these materials with a compound such as is referred to in the first claim,
and subjecting them to heat, substantially as described.
Dated this 27th day of September. 1897.
ABEL & IMRAY,
Agents for the Applicant.