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Патент USA US3074853

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United States Patent O?ice
3,074,843
Patented Jan. 22, 1963
2
1
function of the size and the state of order of the parti
cles. It Was found that the growth of these particles
and their tendency to crystallize can be uniquely con
trolled by the presence of inorganic or organic monova
lent anions and substantially in the absence of nonalumi
3,074,843
PROCESS FOR TREATING CELLULOSE
AND OTHER MATERIALS
Paul Lagally and Herta Lagally, State College, Pa., assign
ors to Linden Laboratories, State College, Pa., a corpo
num-containing polyvalent anions. This controlled po
lymerization makes possible the formation of modi?ed,
partly polymerized forms of aluminum hydroxide which
have optimum interactivity with the cellulose and also
ration of Pennsylvania
No Drawing. Filed Oct. 24, 1958, Ser. No. 769,298
5 Claims. (Cl. 162-181)
This invention relates to the manufacture of paper 10 clay, or other ?ller or pigment if present, thus providing
means for producing paper products which have excellent
dry strength and which may be readily repulped.
In accordance with the present invention paper prod
ucts are produced by forming an aqueous slurry of cel
products of cellulose containing hydroxides or hydrated
oxides essentially of aluminum, the structure of which
has been modi?ed by a. controlled polymerization. This
invention is particularly concerned with the production
of paper products wherein the cellulose and clay, or other 15 lulose, one or more ?llers or pigments if desired, and
partially polymerized aluminum hydroxide produced by
?ller or inorganic or organic pigment, is interacted with
precipitation of aluminum hydroxide from an aqueous
modi?ed forms of hydroxides or hydrated oxides of alu
solution of an aluminum-containing compound in the
minum.
presence of monovalent anions and substantially in the
A speci?c example of one embodiment of this invention
20
is illustrated by the following flowsheet:
absence of nonaluminum-containing polyvalent anions,
and then forming a web or sheet from the product result
ing from the interaction of the cellulose and the partially
polymerized aluminum hydroxide and also the ?llers or
Aqueous solution of an aluminum
salt having monovalent anions
pigments if present.
<-—————————-
NaOH solution
25
‘ Mixing I
invention, in order to properly control the polymerizaé
Aqueous slurry of cellu
lose pulp substantially
free of polyvalent anions
I Mixing
Contrary to the past art of sizing paper, where alumi_
num salts were used primarily as aluminum sulfate, usually
in the form of papermaker’s alum, it is essential to our
tion of aluminum hydroxide and to produce the paper
30 products of our invention, that the aluminum-containing
compound in solution and any agents or materials used
to cause precipitation of the aluminum hydroxide be se
lected so that the desired precipitation is carried out in
the presence of monovalent anions and substantially in
.35 the absence of polyvalent anions other than aluminates.
It has been found that the presence of such ‘polyvalent
It is the prime object of this invention to produce paper
anions, for example, the sulfate ion in a substantial amount
products having extraordinary high dry strength through
will have a serious deleterious effect‘ on the dry strength
the employment of modi?ed and activated aluminum hy
of the ?nished paper product. Therefore, in order to
droxides or hydrated oxides.
~
obtain paper products of our invention, it is necessary to
It is a further object to produce a type of high d
avoid the presence of nonaluminum-containing polyvalent
strength paper which also possesses good wet strength
anions in signi?cant or appreciable amounts.
_
and which may be readily repulped.
It is also a feature of the present invention that the
Aluminum hydroxide, Al(OH)3, is not stable in the
monovalent anions be maintained in the slurry of pre
monomer state because the Al3+ ion requires a coordina
cipitated,
partially polymerized aluminum hydroxide pref
tion of at least four with respect to oxygen. In order
erably at least until the slurry of the cellulose pulp and
to satisfy the coordination demand of the Al3+ ion, mono
the aluminum hydroxide is formed, although removal of
‘ Forming web ‘
mei- Al(OH)3 which is ?rst formed polymerizes and pre
cipitates.
By this polymerization reaction, OH groups of diifer
ent monomer Al(OH)3 molecules are shared and a
a small amount of the monovalent anion is possible with
out serious adverse effect on the properties of the finished
50
paper product. If the precipitated aluminum hydroxide
is puri?ed as by Washing out most of the monovalent
polymerized aluminum ortho hydroxide forms (1). Sub
anions, its properties are changed. Thus, dialyzed alu
minum hydroxide made from aluminum chloride will
sequent condensation results in hydrated chain-like macro
molecules containing aluminum meta hydroxide building
units which are linked together by oxygen bridges (11), 55
until the system, in order to lower its surface free en
ergy, crystallizes. This leads to the formation of
boehmite (III) and of bayerite (IV) as the ?nal reaction
not produce desired results.
‘
As above pointed out, the partially polymerized alu
minum hydroxide of our invention is prepared by pre
cipitation of aluminum hydroxide from an aqueous so
lution of an alumium-containing compound by adjust
product of this aging process, where the degree of polym
ment of the pH of the solution in the presence of mono
erization and the degree of crystallinity can vary within 60 valent anions and substantially in the absence of non
great limits.
[Al(OH)]az
Ortho hydroxide
(amorphous)
(I)
-———>
[-0 A1OH]x.IH2O
aluminum-containing polyvalent anions. Optimum re
sults are obtained by adjustment of the pH within the
range of 6 to 9. The precipitated partially polymerized
aluminum hydroxide may be produced, as will be appre
——>
Meta hydroxide,
hydrated (amorphous)
(11)
[A10 OHImHzO
Meta hydroxide
-—>
[A1(OH);]x
Ortho hydroxide
(cryst., bayerite)
(cryst., boehmite)
(IV)
v
(III)
Figure: Aging of aluminum hydroxide
. The activity of aluminum hydroxide with regard to
cellulose depends on its surface free energy which is a
65 ciated by one skilled in the art, in any one of a number
~ of ways using various materials.
I
'
Thus, one method [involves adjustment of the, pH
of an aqueous solution of an aluminum salt, or mix-'
ture of aluminum salts, having a monovalent an
70 ion by addition of a Water-soluble base or bases. For
_ example, the aluminum salt may be. aluminum chloride,
3,074,843
3
4
aluminum bromide, aluminum iodide, aluminum oxy
chloride, aluminum nitrate, aluminum chlorate, alumi
num salts or from aluminates in the presence of the
cellulose pulp, or when aluminum hydroxide, the struc
num perchlorate. The pH of an aqueous solution of
such an aluminum salt may be adjusted to precipitate alu
minum hydroxide, in accordance with our invention, by
the addition, for example, of an alkali metal hydroxide,
such as sodium hydroxide, potassium hydroxide or lith
ium hydroxide, or of an alkaline earth metal hydroxide
such as calcium hydroxide, magnesium hydroxide, or
of ammonia and its water-soluble derivatives such as
water-soluble amines; for example, ethyl amine, propyl
amine, diethyl amine, monoethanolamine, diethanolamine,
triethanolamine.
Thus for the precipitation of aluminum
hydroxide, all bases can be used under conditions which
prevent re-solution of the previously formed hydroxides.
Another method of preparing the partially polymerized
aluminum hydroxide involves adjustment of the pH of
ture of which has been modi?ed by a controlled polymeri
zation, is added to the pulp, immediate reaction takes
place. The retention is almost quantitative within the
limits of the receptivity of the collulose. The strength
of hand sheets made of the treated pulp is greatly im
proved, resulting in an increase of 200% and more in
dry tensile strength and of 1000% and more in wet ten
10 sile strength. Dry strength papers thus prepared can
be disintegrated by dilute alkalies and dilute acids with
out high temperatures. No further aging of the alumi
num hydroxide retained by the cellulose takes place un
der conditions Where aluminum hydroxide normally
quickly becomes insoluble after thorough drying. This
indicates that a monomer or low polymer type of alumi
num hydroxide is embedded in and screened by the cellu
lose ?bers.
The following examples serve to illustrate the prac
other words using a monobasic acid, either inorganic or 20 tice of the invention:
organic, and mixtures thereof. For example, hydro
EXAMPLE I
an aqueous solution of an aluminate by the addition of
a water-soluble acid having a monovalent anion, in
chloric acid, hydrobasic acid, hydroiodic acid, formic
To a stock slurry of 250 mls. 2% semibleached un
acid, and acetic acid may be employed to neutralize the
beaten kraft cellulose pulp was added simultaneously,
aluminate solution.
with stirring, 20* mls. of an aqueous solution containing
Still another method for preparation of the active
8.3% by weight AlCl3.6H2O and 7 mls. of an aqueous
aluminum hydroxide of our invention involves the inter
solution containing about 10% ammonia. The result
action, and a water-soluble aluminate, such as sodium
ing neutral mixture was diluted with water to 900 mls.
aluminate, and a water-soluble alumium salt having a
This ?nal mixture contained 0.55% cellulose.
monovalent anion, such as above-described. Either ma
Two paper sheets (diameter—19 mm.) were made
terial may be placed in aqueous solution and the pH of 30
of the resulting pulp mixture. The basis weight of the
the solution properly adjusted by the addition of the
blank sheets was 59.4 lbs. (25 x 40 x 500) or 83.5 grams
other material. A speci?c example of this type of reac
per square meter.
tion involves mixing an aqueous solution of aluminum
For the investigation of the dry strength, the sheets
chloride with an aqueous solution of sodium aluminate
in relative amounts such as to result in the desired pre
were exposed to a standardized climate for 12 hours.
cipitation of aluminum hydroxide.
Samples for wet strength were soaked simultaneously in
In the practice of our invention, the partially polym
erized aluminum hydroxide containing the monovalent
water.
The dry tensile strength of the treated sheets was found
to be 13.0 lbs. per inch, that of the blank 5.4 lbs. per
anions may be added to or mixed with the cellulose pulp,
either beaten or unbeaten, preferably containing a ?ller 40 inch. That is an increase in strength of 140%. The
wet tensile strength was found to be 2.29 lbs. per inch
or pigment, or the aqueous solution of the aluminum-con
as compared with 0.34 lb. per inch for the blank. This
taining compound may be added to or mixed with the
is an increase of 570%. The relative Wet strength of
cellulose and ?ller, and the aluminum hydroxide precipi—
tated in situ by adjustment of the pH of the slurry, as
the treated sheet is 17.6% of its dry strength or 42%
above-described. Preferably, an aqueous slurry of the
cellulose pulp, and a ?ller or pigment if desired, is
prepared and to this is added the solution of the alumi
of the dry strength of the blank, respectively.
The ash content of the treated paper was 5.1%. That
is a retention of ‘77% (theoretical retention=6.6%
A1203). This wet strength paper can be digested quickly
num-containing material. Then the pH of the slurry is
in dilute alkalies (NaOH) or acids (HCl).
adjusted by the addition of a suitable material, as above
described, to cause the aluminum hydroxide to precipi~ 50
EXAMPLE II
tate in situ and in the absence of nonaluminum-contain
To a stock slurry of 250 mls. 2% cellulose pulp (semi
ing polyvalent anions. Finally, a web or sheet is formed
bleached kraft) was added 20 mls. 8.3% AlCl3.6H20 so
of the product of interaction of the cellulose pulp and
lution and 6 mls. 40% triethanolamine solution, and the
partially polymerized aluminum hydroxide and ?ller or
pigment if present.
55 mixture was diluted to 900' mls. Two hand sheets were
made. They had a dry tensile strength of 8.0 lbs. per
Whereas precipitated metal hydroxides With a high de
inch and a Wet tensile strength of 2.0 lbs. per inch.
gree of crystallinity have no marked reactivity with such
The relative wet strength is 25%.
compounds as cellulose and clay, it has been found that
gel-like low polymers of Al(OH)3 or AlOOH are highly
EXAMPLE III
active crosslinking agents in aqueous systems, with many 60
To a stock slurry of 250 mls. 2% cellulose pulp (semi
substances which are covered with OH groups. These
bleached kraft) was added 40 mls. 8.3% AlCl3.6H2O so
OH groups may either be attracted from the aqueous
lution and 14 mls. of about 10% ammonia solution.
medium and cause a negative electrokinetic potential,
The mixture was diluted to 900 mls. Two hand sheets
which is signi?cant for cellulose and clay, or they may
form by hydrolysis of surface ions, which is the case with 65 were made of this pulp. The dry tensile strength of the
treated paper was found to be 17.7 lbs. per inch, that
CaCOg, one of the common ?llers. These OH groups
of the blank 5.4 lbs. per inch. The Wet tensile strength
may also be OH groups of constitution, for example, al
of the treated paper was 4.1 lbs. per inch, that of the
coholic hydroxy groups in cellulose. (Do-polymerization
blank 0.34 lb. per inch. The increase of the dry strength
of Al(OH)3 or AlOOH with foreign substances contain
ing OH groups takes place by this reaction, or partly 70 is 228%, that of the wet strength 1200%. The relative
wet strength of the treated paper is 23% or 76% of the
polymerized derivatives of Al(OI-I)3 or AlOOH are pre
dry strength of the blank.
cipitated on the surface of cellulose and compounds such
The ash content of the treated paper was 8.3%. That
as ?llers or other pigments which have similar colloidal
chemical properties.
is a retention of 617.5% (theoretical retention=l2.3%
When aluminum hydroxide forms from suitable alumi 75 A1203).
‘3,074,843
5
6
inch and 'a wet tensile strength of 2.14 lbs. per inch. The
dry strength of the blank was 4.16 lbs. per inch and the
wet‘strength was 0.20 lb. per inch.
This example shows that aluminum hydroxide made of
aluminum chloride where the polymerization of the alu
The paper disintegrates immediately in contact with
0.5% sodium hydroxide solution or hydrochloric acid.
EXAMPLE IV
To stock, slurries of 250 mls. 2% cellulose pulp of vari
mina gel particles is su?iciently controlled by the presence
ous types shown in the table which follows were added
of the Cl- ions retains its activity over a considerable
20 rnls. of an aqueous solution containing 8.3% by weight
length of time.
of A1C3.6H2O and 7 mls. of a solution containing about
EXAMPLE VII
10% ammonia. The resulting neutral mixture was di
luted to 900 rnls., andtwo hand sheets were made.
10
Aqueous solutions, which were 0.345 molar with re—
In all experiments both the dry strength and the wet
spect to Al(OH)3, containing:
strength of the paper sheets were increased considerably.
(a) 11.5% by weight Al2(SO4)3.l8H2O
In the following table WbJOZ/db represents the relative
(b) 13.0% by weight Al(NO3)3.9H2O
wet strength of the blank sheet, and w,;.102/aY-D represents
(c) 8.3% by weight AlCl3.6H2O
the relative wet strength of the treated sheet as compared 15
to the dry strength of the blank. This last value is a meas
ure of the actually achieved increase in wet strength with
out considering the increase in dry strength.
Table
Lbs/inch
were neutralized with ammonia to pH=7 and the result
ing aqueous slurries containing aluminum hydroxide were
stirred at room temperature over a period of several
hours.
20
Tensile strength
Percent
Type of cellulose
ml. portions of 2% cellulose pulp (unbleached kraft).
Dry "
sodiar'lovi iirade:
________________ --
'14 95
Blank __________________ __
1.75
1'69- e
§odaf hit-£11dgrade:
I839
Equal parts of these slurries containing 0.54 gram alu
minum hydroxide (corresponding to 20 rnls. of the alu
minum salt solutions used) were added to successive 250
________________ -_
.
Wet
10.102
db
db
.
4.50
10.72
3.84
17.8
8.4
.
0.10 i
.
0.10 i
0.51 i
13 3
2.94
0.29 i
2.25
10.65
1.81
6.1
2-2
3.28
12.2
8.1
5—7
2 06
3-5
0.45 i
5-5
0.10 i’
Hand sheets of 60 lbs. basis weight Were made of the
25
treated pulp.
Strength data listed below illustrate the in?uence of
aging of aluminum hydroxide on its reactivity to cellulose
'
and also the deleterious effect of the polyvalen tsulfate
133
ion. With aluminum sulfate as starting material, the dry
46 30 strength of paper sheets made of the treated pulp was
substantially less than that of the blank and did not in
crease by aging. To the contrary with aluminum nitrate
and aluminum chloride, an increase in dry strength up
to 200% was obtained. While all three types of hydrox¢
35
35 ides increased the wet tensile strength of the paper made
of the treated pulp, the aluminum hydroxide made of
28
aluminum nitrate and aluminum chloride gave much
higher values than that made with aluminum sulfate.
3°
' 2v 33
1 n 40
'
405.102
1'6
40
EXAMPLE V
Tensile strength, lbs/inch
f‘ To stock slurries of 250 mls. 2% unbeaten 'kraft cel
Aging
lulose pulp was added 20 rnls. of the following solutions
hours
_
A1¢(SO4)3.18H40
containing 0.54 gram equivalents Al(OH)3:
(a) 8.3% by weight AlCl3.6H2O
(b) 12.9% by weight AlBr3.6H2O
Dry
45
Wet
A1(N0s) 3.91120
Dry
Wet
111013515110
Dry
Wet
9.1
7.0
0. 49
1. 25
8.9
13. 4
0.39
2. 59
8. 5
ll. 2
0.40
2.14
6.5
1. 23
15.2 .
2.51
11.0
2.41
the. pulp mixtures. After diluting to 900 rnls., two hand
6. 3
7.1
7. 1
1.36
1. 40
1. 65
15. 5
14. 9
16.1
2. 47
2. 30
2.12
12.1
13. 4
13. 2
2.12
2. 44
2. 29
sheets'of 60 lbs. basis weight were made.
Tensile strength data listed below show that all three
7.0
1. 67
6. 8'
1. 49 __________________ __
aluminum halides yield about equally effective aluminum
7. 6
1. 67
7. 3.
'1. 30 __________________ __
. (c) 14.0% by weight AlI3
Ammonia was added in an amount sufficient to neutralize
7.4
hydroxide.
1.38
.................. __
5. 7
Tensile strength,
.
__________ ________.-_
16.4
18. 0
13. 2
2. 40
2. 41'
1. 61
16.9
2. 41
17.9
2. 31
19. 2
2. 96
>20. 0
2. 76
20.0
3. 46
17. 9
2. 45
_____.._--_ -_-___.___'
1. 94
lbs/inch -
Aluminum hydroxide ‘made of
Dry
Wet
EXAMPLE VIII
To stock slurries of 250 mls. of cellulose pulp (un
60 bleached kraft) were added successive portions contain
ing equal amounts (0.54 gram) aluminum hydroxide
which was obtained as follows:
A. An aqueous solution containing 8.3% by weight
AlCl3.6H-2O was neutralized with ammonia and, the ob
EXAMPLE VI
65 tained mixture containing aluminum hydroxide was aged
' To a stock slurry of Y250 mls. 2% kraft cellulose pulp
for several hours while constantly stirred at room tem
was added, with stirring, a neutral mixture of 20 rnls. of
8.3% AlCl3.6H2O solution with 8.5 mls. of about 10%
B. An aqueous solution containing 8.3% by weight
ammonia, which had been kept at room temperature for
AlCl3.6H2O was neutralizedv with ammonia and the ob
30 minutes. After diluting to 900 rnls. two hand sheets 70 tained mixture containing aluminum hydroxide was al
were made which had a dry tensile strength of 11.0 lbs.
lowed to age for several hours at room temperature with
per inch and a wet tensile strength of 1.90 lbs. per inch.
out‘ stirring.
‘'
After diluting to 900 rnls., hand sheets of 60 lbs. basis
When the AlCl3 solution Was neutralized with ammonia
weight were made‘. 'Tensile strength data listed below
in the presence of the pulp, hand sheets made of the re
perature.
sulting mixture had a dry tensile strength of 10._9_lbs. per
'
'
'
illustrate the in?uence, of stirring on the“ activity of alu:
‘8
minum hydroxide to cellulose pulp. With stirring, con
,siderably stronger hand sheets were obtained.
of‘ a solution containing an aluminate or an aluminum
salt of the type and in the amounts as follows:
Pulp mixture:
Tensile strength, lbs/inch
Aging hours
With stirring
Dry
Wet
8. 9
11.2
16. 9
20. 0
0. 39
2.14
2. 41
2. 76
(1) Blank.
(2) 2.8% Na2A12O4.
W'ithout stirring
_ Dry
8. 2
15. 8
15. 2
12. 3
(3) 2.8% Na2Al2O4.
N3-2A1204
(5) 8.3% AlCl3.6H2O.
(6) 13.0% Al(NO3)3.9H2O.
(7) 11.5% Al2(SO4)3.18H2-O.
Wei:
0. 40
2. 76
2. 83
2. 68
10
Each mixture, except the blank contained aluminum com
EXAMPLE IX
pounds with an aluminum content equivalent to 0.54 gram
of aluminum hydroxide. Pulp mixtures 2 to 4 were then
A stirred aqueous slurry containing 2.83% by weight
sodium aluminate, Na2Al2O4, was saturated with CO2 and
hydrochloric acid. Pulp mixtures 5 to 7 were all neu
tralized with ammonia. Hand sheets of 60 lbs. basis
neutralized respectively With sulfuric acid, nitric acid, and
the bubbling of gas was continued for several hours.
From this solution which had a weakly alkaline reaction
weight were made from the pulp mixtures. Strength data
on these hand sheets are as follows:
(pH=8) aluminum hydroxide of high purity separated.
Increase in Paper Strength,‘ 10% Al(OH)3 Added
Another quantity of the same sodium aluminate solu
tion was partially neutralized to pH=8 using hydrochloric
acid instead of CO2 with the experimental conditions (pH,
temperature, stirring) being the same. Here, the alu~
minum hydroxide was obtained in the form of a highly 25
hydrated gel which did not separate or precipitate.
Equal parts of these mixtures containing 0.54 gram
of aluminum hydroxide were added to successive 250 ml.
portions of 2% unbeaten kraft cellulose pulp. After
diluting to 900 mls. hand sheets of 60 lbs. basis weight
were ‘made of the treated pulp.
' Data listed below show that pure aluminum hydroxide
Tensile strength
Al(0H)s made oi
lbs/inch
Dry
'
Wet
1.
2.
3.
4.
5.
6,
10.9
8.5
16.3
20.0
,18. 0
17.4
0. 40
2.68
3.43
4.42
2.87
3.04
7. Alz(SO4)a+NH4OH _______________________ __
10.7
2. 63
obtained from N2-2A1204 and CO2 was found to be detri
mental, but with HCl as the neutralizing agent, highly
These data show that the presence of sulfate ions has a
active aluminum hydroxide was obtained.
35 deleterious effect on the activity of the precipitated alu
minum hydroxide, the paper web containing it having a
lower dry strength than the blank.
Tensile strength,
lbs/inch
Aging
hours
Dry
Wet
-
The products of this invention are crosslinked cellulose
webs. They have increased dry strength as well as good
Solution
40 wet strength, and they may be readily repulped if de
sired.
NazA1zO4+COz_
10. 0
6. 4
0. 44
0. 56
NazAlzO 4+0 0:.
NazAlzOH-COz.
G. 6
7. 8
0. 53
O. 54
N?zAlzOH-COz.
8. 3
O. 46
NazAlzO?-C Oz _____________________ _ _
9. 1
0. 69
10. 0
0. 44
14. 2
2. 95
N?zAlzOs-I-HCL. _
NazA1zO4+H C1. _ _
16. 9
, > The strength of paper is ordinarily limited by the ?ber
to-?ber bonds.
bonds to an amount comparable with the tensile strength
45 of the single ?bers, which approaches that of steel.
22. 5
2. 32
N?zAlnOH-HCI ..................... _-
23. 5
3. 11
So
far as is known, there is no process which would permit
the manufacture of a paper product which has consider
2. 82
Na2Al9O4+HCL --
No process has been reported so far
which would increase the strength of these ?ber-to-?ber
ably increased dry strength, without special equipment
or subsequent treatment of the paper.
50
EXAMPLE X
To 120 mls. of a stirred aqueous solution containing
2.83% by weight of sodium aluminate was added 3 mls.
acetic acid and stirring was continued for several hours.
Equal parts of the neutral mixture obtained containing 55
0.54 gram aluminum hydroxide were added to successive
Several paper
resins, which improve the dry strength only moderatelyv
are in use mainly to improve the Wet strength of paper.
The drawbacks of these products are well-known. Mela
mine formaldehyde resins can ‘be stored for a consider
able length of time, but they must be cured by a well
controlled acid treatment in order to achieve substantivity
to the cellulose ?bers. Substantive urea formaldehyde
250 ml. portions of 2% cellulose pulp (unbleached kraft).
resins are commercially available, but they generally have
After diluting to 900 mls., hand sheets of 60 lbs. basis
only a limited life. Most paper resins are effective only
weight were made.
in the acid medium. Polyethyleneamine, on'the'otherv
Data listed below give the increase in tensile strength 60 hand, needs an alkaline medium in order to be retained
obtained with this type of active aluminum hydroxide.
by the cellulose. The retention of many of these resin
colloids is insuiiicient, and the treated paper must be
Tensile strength,
cured in order to develop maximum strength properties.
Aging
lbs/inch
The recovery of the broke and the de-inking of such wet
hours
Solution
65 strength papers conventionally treated with resins of the
D S’
Wet
Allllélillllm hydroxide. _._
_-__-
0 ___________________ __
EXAMPLE XI
Seven 250 ml. stock slurries containing 2% unbleached
amine type presents considerable disadvantages.
Paper products treated according to this invention avoid
these disadvantages. The coordination forces of poorly
screened cations strongly attract surface OH groups of
70 cellulose and other compounds present, for example,
?llers, and the strength of ?ber-to-?ber bonds or bonds
between the surface of ?bers and ?llers is increased. Dry
strength of the paper is increased to a surprising degree.
kraft pulp were prepared. - There was then added 20 mls. 75
The chemicals used are economic and can be stored in
de?nitely. The active hydroxides have high substantivity
3,074,843
to cellulose and exhibit maximum reactivity in neutral
media. Since no curing is necessary, maximum strength
properties are obtained while the paper is being dried,
and the disintegration of the paper and recovery of the
broke needs no special processing.
10
the product resulting from interaction of the cellulose
pulp and the aluminum hydroxide, said aluminum hy~
droxide ‘being present in an amount of from 0.5 percent
to 20 percent based on the weight of the cellulose pulp.
3. A process for producing paper products which
comprises the steps of forming an aqueous solution of
an aluminum-containing compound selected from the
group consisting of water soluble aluminum salts having
types of cellulose consist mainly of short and broken
monovalent anions and water soluble aluminates; mix
?bers and of degradation products thereof. The high
speci?c surface of such low grade ?brous material is ac 10 ing said solution with cellulose pulp substantially free of
polyvalent anions, adjusting the pH of the resulting mix
tivated by the interaction with the modi?ed aluminum
ture, substantially in the absence of nonaluminum-con
hydroxides and paper of high grade is obtainable. The
taining polyvalent anions, to cause precipitation of
treated paper, in addition to its outstanding strength prop
amorphous aluminum hydroxide, thereby forming an
erties, is very tough and ?exible. It shows no brittleness,
since no binding material of larger particle size, ‘which 15 aqueous slurry of cellulose pulp and precipitated alumi
num hydroxide containing monovalent anions in solu
would separate the ?bers, is deposited.
tion; and then forming a web from the product resulting
In practice of the invention, from 0.5% to 210% by
from interaction of the cellulose pulp and the aluminum
weight of aluminum hydroxide is preferably employed,
hydroxide, said aluminum hydroxide being present in an
based on the weight of cellulose in the dry sheet.
amount of from 0.5 percent to 20 percent based on the
Products manufactured in accordance with the process
weight of the cellulose pulp.
of the present invention are all kinds of paper in which
4. A process for producing paper products which com
increased strength properties are desired, such as wrap
prises the steps of forming an aqueous slurry of cellulose
ping papers, spinning papers, papers for highway con
pulp, substantially free of polyvalent anions, and amor
struction, wet strength towels, wet strength paper bags,
wet strength ?lter webs, map papers, all types of printing 25 phous aluminum hydroxide produced by precipitation,
substantially in the absence of nonaluminum-containing
paper which contain ?ller particles uniformly distributed
polyvalent anions, of aluminum hydroxide from an aque
through the paper sheet or papers used for arti?cial leath
It is particularly important that cellulose pulp of poor
grade can be improved considerably by this process. Such
er or as backings for pressure sensitive adhesive tapes,
ous solution of an aluminum salt having a monovalent
anion, and forming a web from the product resulting
which contain elastomeric impregnants deposited on the
?bers and which are characterized by high tear strength 30 from interaction of the cellulose pulp and the aluminum
hydroxide, said aluminum hydroxide being present in an
and high delamination resistance.
amount of from 0.5 percent to 20 percent based on the
The invention in its broader aspects is not limited to
weight of the cellulose pulp.
the processes described, but departures may be made
5. A process for producing paper products which com
therefrom within the scope of the accompanying claims.
prises the steps of ‘forming an aqueous slurry of cellulose
This application is a continuation in part of our co
pulp, substantially free of polyvalent anions, and amor
pending application Serial No. 616,373, ?led October 17,
1956, now abandoned.
We claim:
1. A process for producing paper products which com
phous aluminum hydroxide produced by precipitation,
substantially in the absence of nonaluminum-containing
polyvalent anions, of aluminum hydroxide from an aque
prises the steps of forming an aqueous slurry of cellulose 40 ous solution of an aluminate, and forming a web from
the product resulting from interaction of the cellulose
pulp, substantially free of polyvalent anions, and amor
pulp and the aluminum hydroxide, said aluminum hy
phous aluminum hydroxide produced by precipitation of
droxide being present in an amount of from 0.5 percent
aluminum hydroxide from an aqueous solution of an alu
to 20 percent based on the weight of the cellulose pulp.
minum-containing compound in the presence of mono
valent anions and substantially in the absence of non 45
References Cited in the ?le of this patent
aluminum-containing polyvalent anions, and forming a
web from the product resulting from interaction of the
UNITED STATES PATENTS
cellulose pulp and the aluminum hydroxide, said alumi
1,713,642
Booth ______________ .. May 21, 1929
num hydroxide being present in an amount of from 0.5
2,085,129
vStoewener __________ __ June 29, 1937
percent to 20 percent based on the weight of the cellulose
2,593,125
Eaton ______________ __ Apr. 15, 1952
pulp.
2. A process for producing paper products which com
prises the steps of forming an aqueous solution of an
aluminum-containing compound selected from the group
consisting of water soluble aluminum salts having mono
valent anions and water soluble aluminates; adjusting the
pH of said solution, substantially in the absence of non
2,661,288
2,825,645
2,917,426
2,930,106
Barbaras ____________ .... Dec. 1,
Eichmeier ___________ __ Mar. 4,
Bugosh _____________ .._ Dec. 15,
Wrotnowski ________ _.. Mar. 29,
1953
1958
1959
1960
FOREIGN PATENTS
89,291
844,945
631,483‘
Sweden _____________ .. May 19, 1937
France ______________ __ May 1, 1939
Great Britain ________ .. Nov. 3, 1949
aluminum-containing polyvalent anions, to cause precipi
tation of amorphous aluminum hydroxide, thereby form 60
OTHER REFERENCES
ing an aqueous slurry of precipitated aluminum hydrox
ide containing monovalent anions in solution; then, with
Rowland et al.: “The Alumina Content of Rosin Free
out removing said monovalent anions from said slurry,
Hand Sheets in Relation to Tub Sizing,” Paper Trade
mixing cellulose pulp substantially free of polyvalent
Journal, vol. 119, No. 20, November 16, 1944, pages
anions with said slurry; and ?nally forming a web from 65 29-33,
UNITED STATES PATENT OFFICE
CERTIFICATE OF CORRECTION
Patent No. 3,074,843
January 22, 1963
Paul Lagally et a1,
It is hereby certified that error appears in the above vnumbered pat
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 3, line 22, for "hydrobasic" read ~~ hydrobromic ~~—;
line 27, strike out ", and" and insert instead —— of ——; column
6, line 28, for "polyvalen tsulfate" read -— polyvalent
sulfate ——; column 7, lines 35 to 50, and lines 62 to 72, in
the tables, second columns headings strike out "Solution", each
occurrence; third columns headings of the tables for "Tensile
strength, lbs./inch", each occurrence, read —— Tensile strength
(lbs ,/inch) ; the word "Blan/R?appearing in the first line 01"
each
group, should be changed to
the second column of each
group,
'
(SEAL)
Signed and sealed this 20th day of August 1963,,
Attest:
ERNEST w. SWIDER.
Attesting Officer
'
DAVID L- LADD
Commissioner of Patents
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