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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to a sizing composition for paper making, and
more particularly to an internal sizing composition having an excellent
self-emulsifying property suitable for use in neutral paper making.
Hitherto, as a sizing agent for use in paper making, there have been
broadly used various sizing agents, for example, sizing agents prepared
from natural rosin or denatured rosin and the like, and particularly
fortified rosin sizing agents prepared by saponifying the addition
reaction product of rosin and maleic acid.
These sizing agents are employed in acid sizing method in which they are
fixed to paper fibers by aluminum sulphate. However, the acid sizing
method has a number of drawbacks that devices or machines employed in
paper making are corroded and that strength and durability of the obtained
paper deteriorates because of pH drop in pulp slurry due to employment of
aluminium sulphate which is an essential component in paper making by the
acid sizing method.
Also, there is little hope that the cost of paper making is lowered largely
because cheap alkaline fillers such as calcium carbonate are difficult to
use in the acid sizing method.
For the purpose of eliminating such drawbacks of the acid sizing method, a
neutral paper making method in which aluminium sulfate is not employed was
studied and there have been proposed neutral sizing agents capable of
imparting an excellent sizing effect to a paper under a papr making
condition in neutral region. Examples of such a neutral sizing agent are,
for instance, a sizing agent containing cyclic dicarboxylic acid anhydride
described in Japanese Examined Patent Publication (Tokkyo Kokoku) No.
2305/1964, a sizing agent prepared by addition reaction of an olefin
having a double bond at its inner part and maleic anhydride described in
Japanese Examined Patent Publication No. 28526/1978 and a sizing agent
consisting of substituted dicarboxylic acid anhydride, polyoxyalkylene
compound and water described in Japanese Examined Patent Publication No.
36044/1978 and the like.
However, both sizing agents described in Japanese Examined Patent
Publications No. 2305/1964 and No. 28526/1978 have many limitations in
order to disperse the dicarboxylic acid ayhydride in water as clearly
understood from the description in Japanese Examined Patent Publication
No. 36044/1978. They can be dispersed in water only when protective
colloids which are emulsifiers such as cationic starch, gelatine and
polyvinylalcohol are added, and a special device for violent agitation
such as high-speed vibrator, mechanical homogenizer or ultrasonic wave
homogenizer is used.
There is described in Japanese Examined Patent Publication No. 36044/1978
that the emulsifying process employing such a violent agitator can be
omitted by using polyoxyalkylene compound as a surfactant in combination
with the substituted dicarboxylic acid anhydride. Thus, in case of
dispersing the substituted dicarboxylic acid anhydride in water with usage
of a surfactant described in Japanese Examined Patent Publication No.
36044/1978 such as polyoxyalkylene alkyl ether or polyoxyalkylene
alkylaryl ether, emulsification can be achieved only by passing the
admixture containing the substituted dicarboxylic acid anhydride through a
pulp-mixing aspirator or orifices without agitating violently.
However, admixture of the substituted dicarboxylic acid anhydride and the
above-mentioned surfactant has a tendency to lower its dispersibility in
water as passage of time and thus, a tendency of lowering its sizing
effect.
Also, when polyoxyalkylene alkyl diester is used as a surfactant as
described in Japanese Examined Patent Publication No. 36044/1978, an
admixture containing the diester does not have such a drawback of lowering
sizing effect with passage of time as an admixture in which
polyoxyalkylene alkyl ether or polyoxyalkylene alkyl aryl ether is added.
But, polyoxyalkylene alkyl diester has another drawback that the ester is
not easily dispersed in water by normal mixing operation because the ester
has many carbon atoms in its alkyl group and thus, is a strong
hydrophobicity.
Therefore, as easily understood from the above description, any dispersing
agent disclosed in the above Publications cannot be used preferably.
The well-known neutral sizing agents cannot simultaneously satisfy the
dispersibility in water, the storage stability and the sizing effect.
Consequently, an acid paper making method employing the fortified rosin
sizing agent is still mainly conducted.
The object of the present invention is to provide a neutral sizing
composition suitable for use in paper making which solves the
above-mentioned problems and can be employed preferably in practical use
comparing favorably with the fortified rosin sizing agent.
SUMMARY OF THE INVENTION
It has now been found that a neutral sizing composition into which a
specific surfactant is added can simultaneously satisfy the dispersibility
in water, the storage stability and the sizing effect.
In accordance with the present invention, there is provided a
self-emulsifying sizing composition comprising:
(A) at least one member selected from the group consisting of;
a substituted succinic anhydride having a linear or branched substituent of
the formula (I):
##STR1##
wherein R.sup.1 is an alkyl or alkenyl group having 9 to 23 carbon atoms,
and
a substituted succinic anhydride of the formula (II):
##STR2##
wherein R.sup.2 is an alkyl group having 1 to 27 carbon atoms, R.sup.3 is
an alkyl or alkenyl group having 2 to 28 carbon atoms and a total number
of carbon atoms in R.sup.2 and R.sup.3 is 9 to 29, and
(B) at least one member selected from the group consisting of:
an acetylated polyoxyethylene sorbitan fatty acid ester, and
a polyoxyethylene compound of the formula (III):
##STR3##
wherein R.sup.4 is an alkyl group having 8 to 20 carbon atoms, n is an
integer from 3 to 30 and A is oxygen atom, phenyleneoxy group or
##STR4##
DETAILED DESCRIPTION
A substituted succinic anhydride of the formula (I) usable in the present
invention is obtained by addition reaction of linear or branched
.alpha.-olefin and maleic anhydride.
Examples of such a substituted succinic anhydride are, for instance,
iso-octadecenyl succinic anhydride, n-hexadecenyl succinic anhydride,
dodecenyl succinic anhydride, triiso-butenyl succinic anhydride and the
like. A substituted succinic anhydride having saturated substituent
obtained by hydrogenation of the above-mentioned substituted succinic
anhydride having unsaturated substituent is also employed.
A substituted succinic anhydride of the formula (II) is obtained by
addition reaction of olefin having a double bond at its inner part and
maleic anhydride.
Examples of such an olefin are preferably linear inner olefins, for
instance, decene-5, dodecene-6, tetradecene-7, hexadecene-7, octadecene-9,
eicocene-11 and the like. Both substituted succinic anhydride having
saturated substituent and substituted succinic anhydride having
unsaturated substituent are employed in the present invention.
The addition reaction of .alpha.-olefin or olefin having a double bond at
its inner part and maleic anhydride is carried out with or without
catalyst, preferably under an inert atmosphere at atmospheric or elevated
pressure. Reaction temperature is 180.degree. to 250.degree. C.,
preferably 190.degree. to 220.degree. C. and reaction period is 1 to 50
hours, preferably 10 to 36 hours.
Molar ratio of maleic anhydride and the olefins employed in the addition
reaction is not limited. Maleic anhydride is generally used in an amount
of 0.4 to 2 moles, preferably 0.8 to 1.3 moles per 1 mole of the olefins.
The substituted succinic anhydride can be obtained by distilling away
unreacted olefins and maleic anhydride.
Specific dispersing agent essentially necessary for the present invention
is limited to at least one member selected from the group consisting of
acetylated polyoxyethylene sorbitan fatty acid ester and polyoxyethylene
compound of the formula (III).
The acetylated polyoxyethylene sorbitan fatty acid ester can be prepared as
follows. At first, sorbitan, i.e. a mixture of 1,4-sorbitan and
3,6-sorbitan which are one-molecule dehydrated compound of sorbitol and
obtained by intramolecular dehydration of sorbitol, and 1,4,3,6-sorbide
which is two-molecule dehydrated compound of sorbitol and obtained by
intramolecular dehydration of sorbitol is subjected to esterification
reaction with fatty acid to give sorbitan fatty acid ester. Then, the
obtained ester is subjected to addition reaction with ethylene oxide.
Finally, acetylation of terminal hydroxyl group of the reacted compound is
carried out with acetic anhydride to give the object compound. The fatty
acid used in the above procedure is saturated or unsaturated fatty acid
having carbon atoms of 8 to 20, preferably 10 to 18. Number of added
ethylene oxide molecules per one side chain of a sorbitan fatty acid ester
is generally in a range of 3 to 30, preferably 5 to 20.
In the above-mentioned esterification reaction, di-esterificatied and
tri-esterificated compound are formed as by-products in addition to
mono-esterificated compound as main product. Consequently, the acetylated
polyoxyethylene sorbitan fatty acid ester is produced, as long as
conventional industrial process is employed, as a mixture of mono-, di- or
tri-ester of acetylated polyoxyethylene sorbitan fatty acid.
Although mono-ester of acetylated polyoxyethylene sorbitan fatty acid is
preferable for use in the present invention, a mixture containing di-ester
and tri-ester of acetylated polyoxyethylene sorbitan fatty acid can be
employed in the present invention without any disadvantage.
According to the present invention, the dispersing agent is required to
have no hydroxyl groups and to have adequate hydrophilic property. A
mixture of such a dispersing agent and the substituted succinic anhydride
of the formula (I) and/or (II) is chemically so stable that a ring
cleavage of the substituted succinic anhydride does not occur and thus,
water-dispersibility of the mixture does not change with passage of time.
Such a dispersing agent is superior in self-emulsifying property because
of its adequate hydrophilic property. Consequently, a smaller amount of
the dispersing agent is effective in comparison with the conventional
dispersing agent such as polyoxyalkylene alkyl ether or polyoxyalkylene
alkylaryl ether. Therefore, problems encountered at a time of using a
conventional dispersing agent such as bubbling can be eliminated.
Anionic surfactants such as potassium, sodium and calcium
dodecylbenzenesulfonate and laurylsulfate can also be used simultaneously
in combination with the dispersing agent of the present invention.
The self-emulsifying sizing composition of the present invention can be
employed in paper making by a manner that a desired amount of aqueous
dispersion of the sizing composition is added to a pulp slurry or a
desired amount of the sizing composition is added to a pulp slurry
simultaneously with the addition of water in desired proportion. For a
purpose of improving a fixing property of the sizing agents against pulp,
for example, polyethyleneimine resin, cationic polyacrylamide resin,
cationic polyamidepolyamine resin and derivatives of cationic starch can
also be employed in the composition.
The present invention is more specifically described and explained by means
of the following Examples. It is to be understood that the present
invention is not limited to the Examples, and various changes and
modifications may be made in the invention without deparing from the
spirit and scope thereof.
In the Examples, the sizing effect of the composition of the present
invention was investigated according to the following testing method.
Sizing Effect
To a 1% slurry of a L-BKP pulp beaten to 450 ml of Canadian standard
freeness were added polyamidepolyamine resin (commercially available under
the commercial name "Arafix 100" made by Arakawa Kagaku Kogyo Kabushiki
Kaisha) in an amount of 0.3% (calculated as solid matter) based on the
weight of the pulp as a fixing agent and the sizing composition obtained
in the Example in an amount of 0.2 or 0.5% (calculated as solid matter)
based on the weight of the pulp. After uniformly dispersing, the slurry
was subjected to paper making by using a TAPPI standard sheet machine to
give a sheet having a basis weight of 60.+-.1 g/m.sup.2. The obtained wet
sheet was pressed to dehydrate and then dried at 100.degree. C. for 1
minute. After conditioning at a relative humidity of 65% for 24 hours, the
sheet was subjected to the measurement of the sizing degree (second)
according to a Stoeckight method.
Also, the following Reference Examples are presented to illustrate the
preparation of substituted succinic acids as used in the present
invention.
REFERENCE EXAMPLE 1
An alkenyl-substituted succinic anhydride was prepared by addition reaction
of maleic anhydride with branched .alpha.-olefins having 14 carbon atoms.
REFERENCE EXAMPLE 2
An alkenyl-substituted succinic anhydride was prepared by addition reaction
of maleic anhydride with isobutylene oligomer having 20 carbon atoms.
REFERENCE EXAMPLE 3
An alkenyl-substituted succinic anhydride was prepared by addition reaction
of maleic anhydride with tetradecene-7.
REFERENCE EXAMPLE 4
An alkenyl-substituted succinic anhydride was prepared by addition reaction
of maleic anhydride with eicocene-11.
REFERENCE EXAMPLE 5
An alkenyl-substituted succinic anhydride was prepared by addition reaction
of maleic anhydride with octadecene-9.
EXAMPLE 1
There were well admixed 10 g of the alkenyl-substituted succinic anhydride
obtained in Reference Example 1 and 1 g of the emulsifier of the
acetylated polyoxyethylene sorbitan fatty acid ester shown in Table 1.
1 g of the obtained admixture was collected in a bottle of 100 ml and 86 g
of water was added. The admixture was emulsified by shaking the bottle
lightly to give a sizing agent.
EXAMPLES 2 TO 11
The procedures of Example 1 were repeated except that substituted succinic
anhydrides and dispersing agents shown in Table 1 were employed to give
sizing agents by emulsifying the admixtures.
Self-emulsifying property of the sizing agents obtained in Examples 1 to 11
was measured just after the preparation and at 7 days after the
preparation. The results are shown in Table 1, in which Sorgen TW-20 and
Sorgen TW-60, employed in Example 10 and 11, respectively are emulsifier
of sorbitan fatty acid ester made by Dai-ichi Kogyo Seiyaku Kabushiki
Kaisha.
TABLE 1
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Self-emulsifying
property
Substituted just after
7 days
Sizing effect
succinic Dispersing the after the
(sec)
anhydride agent preparation
preparation
0.2%
0.5%
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Ex. 1 Ref. Ex. 1
##STR5## good good 10 25
Ex. 2 Ref. Ex. 2
" good good 15 30
Ex. 3 Ref. Ex. 3
" good good 12 29
Ex. 4 Ref. Ex. 4
" good good 20 35
Ex. 5 Ref. Ex. 5
" good good 19 34
Ex. 6 Ref. Ex. 5
##STR6## good good 18 32
Ex. 7 Ref. Ex. 5
##STR7## good good 18 32
Ex. 8 Ref. Ex. 5
##STR8## good good 18 32
Ex. 9 Ref. Ex. 5
##STR9## good good 18 32
Ex. 10 Ref. Ex. 5
Acetylated Sorgen TW-20 good good 16 35
Ex. 11 Ref. Ex. 5
Acetylated Sorgen TW-60 good good 14 32
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Description |
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