Note: Descriptions are shown in the official language in which they were submitted.
105Z5~9
This invention relates to improved paper-forming fibrous materials
and to methods for producing the same.
The idea of producing paper-forming fibers from an emulsified disper-
sion of a polymer solution, and jet-extruding, has been disclosed in British
Patent No. l,323,174. The paper-forming fibrous materials mainly composed of
poly-~-olefin thus obtained have large specific surface areas and can be suspend-
ed effectively in water.
Synthetic paper made of this paper-forming fibrous material alone, or
combined with cellulose pulp, has excellent uniformity, mechanical properties,
brightness and opacity. Such fibrous materials, however, have a tendency to-
ward forming and sending up bubbles in water and to float when formed into a
slurry and strongly agitated.
This not only leads to lack of uniformity of the paper sheet, but also
leads to many difficulties in storage or transportation of the slurry. This is
believed to be due to elution into water of surface active agents which are
included in or fixed on the fibrous materials during disintegrating or beating
and their foaming effect.
It is an important object of the present invention to provide an im-
proved paper-forming fibrous material by flash-spinning an emulsified disper-
sion of a polymer solution.
Another object of the invention is to provide a method for producinga paper-forming material in which surface active agents or hydrophilic polymers
are substantially free of elution into water and thereby can exhibit their
hydrophilic properties effectively.
A paper-forming material in accordance with the present invention is
obtained by preparing an emulsion composed of (a) a poly-~-olefin, (b) an or-
ganic solvent having a lower boiling point than the melting point of said poly-
~-olefin, ~c) a dispersion medium which is a non-solvent for said poly-~-olefin
and which is also substantially incompatible with the said organic solvent,
and (d) a polymeric surface active agent having a structure selected from the
group consisting of:
I ~ -1-
:~0~5~
Rl
~ CH --- FH~-----~CH2--- C ---~-
C=O C=O R2
A B
(II) --~CH2--- IH~-- __~CH2___C --3- or --~CH2-- C~ CH2-- C --3
C20 R2 C=O R2
,0 0,
A A
(III) ( CH2 - CH2) (CH2 -- ll~)
R5
and (IV) a vinyl monomer-grafted polyvinyl alcohol prepared by graft polymeris-
ing from 5 to 2000% by weight of vinyl monomer, based on the polyvinyl alcohol,
wherein A and B represent members selected from the group consisting of hydro-
gen, hydrocarbon radicals having from one to twenty carbon atoms, Li, Na, 1/2
Ca, 1/2 Mg, 1/2 Zn and 1/3 Al; Rl represents a member selected from the group
consisting of hydrogen and a hydrocarbon radical having from one to thirty
carbon atoms; R2 represents a member selected from the group consisting of hy-
drogen, -COOR3 ~in which R3 represents hydrogen or a hydrocarbon radical having
from one to thirty carbon atoms), -OCOR4 (in which R4 designates a hydrocarbon
radical having from one to twenty carbon atoms), halogen and -CH2OH; and R5
represents a member selected from the group consisting of -OCOR6 (in which R6
represents a hydrocarbon radical having from one to twenty carbon atoms), -OH
and -CH20H, and each polymer of formula I, II or III has a molecular weight of
10,000 to 1,000,000; the amount of poly-a-olefin (a) being from about 5 to 40%
by weight of said solvent (b), the amount of surface active agent ~d) being
from about 0.5 to 40% by weight of said poly-~-olefin (a) and the ratio of dis-
persion medium (c) to solvent ~b) being from 1:6 to 6:1, and jet-extruding the
emulsified dispersion through an orifice.
The emulsified dispersion is ejected through the orifice at autogen-
ous pressure or at a pressure above au~ogenous pressure.
When conventional surface active agents (low molecular weight) are
used in emulsion flash-spinning, various hydrophilic polar polymers previously
mentioned ~British Patent No. 1,323,174) are usually blended with polyolefin
~ 2-
~05ZS~9
in order to improve their dispersing properties, self-bonding ability and af-
finity for the cellulose pulp of the paper-forming fibrous material obtained.
That is, in conventional emulsion flash_spinning hydrophilic polymers have been
used as hydrophilic agent, while conventional low molecular weight surface ac-
ti~e agents have been used as emulsifier.
The present invention relates to specific surface active agents used
effectively in emulsion flash-spinning, namely polymer surface active agents
which not only act as emulsifiers but also contribute hydrophilic and self-
bonding properties to the paper-forming materials which are mainly composed
of poly-a-olefins.
Examples of poly-a-olefins used as an important component of the
paper-forming material of the present invention include polyethylene, polypro-
pylene, poly-l-butene, poly-4-methyl-1-pentene and copolymers of two or more
a-olefin monomers.
Referring now to the solvents that may be used in the practice of the
present invention, hydrocarbons such as pentane, hexane, heptane and benzene
and chlorinated hydrocarbons such as methylene chloride and chloroform are pre-
ferable. Mixed solvents may also be used. For the dispersion medium, water,
glycerin, glycol and their mixtures may be used. In general, water is prefer-
able.
The concentration of the polymer mixture in the solution is from about
5 to 40% by weight. When the concentration is less than about 5%, the amount
of paper-forming material produced is small and the resulting fibers become
short and have poor intertwining properties. When the concentration is higher
than about 40%, the dispersion is more apt to coalesce because of the higher
viscosity of the polymer. This leads to the production of a continuous fibrous
material which is rough in its morphological structure and is difficult to dis-
integrate.
~.,1~.,
--3--
105Z5~9
According to this invention, the solution containing the polymer
mixture main]y composed of poly~l-olefin and ~-olefin copolymer is disper-
sed as small particles in the dispersion medium. The dispersion medium and
the solvent are present in the ratio of from about 1:6 to 6:1 by volume.
When the ratio of the dispersion medium to the solvent is too small, it is
difficult for the solvent to disperse as small particles in the dispersion
medium, and a so-called continuous fiber which is difficult to disintegrate
may be formed because of inversion of the dispersed phase and the dispersion
medium, or because of coalescing of the dispersed phase. When the ratio of
dispersion medium to solvent becomes excessive, the jet-extruded material
assumes the form of finely divided particles. This results in the production
of very short fibers which have poor intertwining properties when formed
into paper. Moreover, the proportion of polymer in the resulting jet-extrud-
ed material is too small and the production rate of the fibrous material is
too low.
In the practice of the present invention polymers having a struc-
ture heretofore referred to by the formulas (I), (II), (III) or (IV) are used
alone or combined with each other as an emulsifier and hydrophilic polymer in
~ a~ll
~L~ emulsion ~sh-spinning.
Polymers having either structure (I), CII) or (III) and having a
molecular weight of from about 10,000 to 1,000,000, when used in emulsion
flush-spinning, are introduced onto the surface of paper-forming material and
~t ~
lead to bonding b~een the paper-strengthening agents which are conventionally
used in the internal sizing or the size press coating. Thereby the surface
5 ~ren~h
sireRgtqs of paper sheets composed of such paper-forming materials together
with cellulose pulp is remarkably improved. On the other hand, when polymers
having structures (I), (II) or (III) are not used as emulsifiers, paper sheets
composed of paper-forming materials and cellulose pulp give inferior surface
strengths even if paper-strengthening agents are used in internal sizing or
size press coating.
1()5;~S19
As examples of polymers having structures of the formulas (I), (II)
or (III), used in the practice o~ the present invention, mention should be
made of styrene-maleic anhydride copolymer and its hydrolyzed product, sty-
rene-sodium maleate copolymer, styrene-methyl methacrylate-calcium or sodium
maleate copolymer, styrene-methyl methacrylate-sodium salt of a half ester of
maleic acid copolymer, ethylene-aluminum maleate copolymer, ethylene-acrylic
acid copolymer, ethylene-sodium acrylate copolymer, ethylene-vinyl acetate
copolymer, styrene-methacryclic acid copolymer, styrene-lauryl methacrylate-
sodium methacrylate copolymer, saponified ethylene-vinyl acetate copolymer,
ethylene-allyl alcohol copolymer and poly (sodium methacrylate).
Polymers having a structure represented by (I), (II) or (III) have
a hydrophilic component (e.gO an alkali metal salt of a carboxylic acid group)
and ~ lipophilic component (e.g. a polymer chain or hydrocarbon radicals) in
themselves and therefore function as surface active agents. The said struct-
ural units represented by these general formulas may be used alone or as a
mixture of at least two components in order to change the HLB (hydrophilic
and lipophilic balance) of the polymers.
Combinations of surface active agents having different HLB values
are well known to give more stable emulsions. Thus, a mixture of these poly-
mers may be used.
Examples of vinyl monomers in vinyl monomer-grafted polyvinyl al-
cohol used in the practice of the present invention include monomers which
are compatible with organic solvents, such as styrene, vinyl acetate and
alkyl acrylate or methacrylateO ~ater soluble monomers such as acrylamide
and acrylic acid give a lesser surface active effect when grafted on poly-
vinyl alcohol, because such graft-copolymers have poor lipophilic properties.
pre~ r~b~
In graft-copolymerization it is prcfcr~ to use completely saponified or
pàrtially saponified polyvinyl alcohol having a polymerization degree of from
200 to 4000. Graft copolymerization of vinyl monomer on polyvinyl alcohol
is initiated by the usual radical initiators in an aqueous polyvinyl alcohol
105'~5~9
solution.
~ xamples of initiators include ammonium persulfate, potassium per-
sulfate, cerium ammonium nitrate and various organic peroxides.
When vinyl nomer-grafted polyvinyl alcohols obtained by the above
graft-copolymerization procedure act as surface active agents in emulsion
-spinning, lipophilic polymer chains are introduced into the solvent
particles and entangled with polymer chai~s of poly- ~olefin dissolved in
the pàrticles. Thus, the vinyl monomer-grafted polyvinyl alcohols are fixed
firmly in the fibrous materials. Thereby an aqueous dispersion of such a fib-
rous material causes much less foaming upon beating or strong agitation than
occurs with a slurry of fibrous material obtained by using a conventional sur-
face active agent of low lecular weightO
Moreover, when using a vinyl nomer-grafted polyvinyl alcohol as
a surface active agent, segments of the polyvinyl alcohol are fixed in the
polyolefin fibrou9 materials, as is mentioned above~ and the fibrous mater-
ial accordingly acquires good hydrophilic properties.
The a unt of vinyl nomer fed in the graft copolymerization pro-
cedure is ~ from about 5 to 2000% and more preferably from about
25 to ~OO% by weight based on polyvinyl alcohol. When the amount of grafted
vinyl monomer is too low, the polyvinyl alcohol has a less lipophilic charac-
ter and is easily miscible with water. On the other hand, when the a unt of
gràfted vinyl nomer is excessive, its surface active properties do not ap-
pear to a significant degree. Formation of homopolymers of the vinyl monom-
er in graft copolymerization does not interfere with the effect of the pres-
ent invention.
The amount of polymeric surface active agent represented by formul-
as (I), (II), (III) or (IV) used in the practice of the present invention is
S4rtb~ from about 0.5 to 40%, re preferably from 1 to 30% by weight,
based on the weight of the poly-d -olefin.
These polymeric surface active agents may also be used with conven-
105'~519
tional surface active agents of low molecular weight.
Other surface active agents include (1) anionic surface active
agents, for example, carboxylic acid salts, sulfuric acid esters, sulfonic
acid salts and phosphoric acid esters; (2) cationic surface active agents;
(3) anionic and cationic surface active agents, for example, amino acid
salts and betaine compounds; and (4) non-ionic surface active agents, for
example, polyethylene glycol types and polyhydric alcohol types. In the
present invention, these surface active agents may also be used with the
previously mentioned polymeric surface active agents having formulas (I),
(II), (III) or (IV)~
If desired, it is possible to add other hydrophilic or water
soluble polymers, pigments~ stabilizer, antistatic reagents~ binders, sizing
agents or other substances to the poly-a-olefin, provided the amount added
is in a proper proportion and does not interfere with the proper functioning
of the present invention.
Examples of preferred compositions of polymer mixture and surface
active agents are as follows:
A. polypropylene 100 parts
ethylene-vinyl acetate copolymer20 parts
ethylene-sodium acrylate copolymer 3 parts
sodium dodecylbenzene sulfonate3 parts
B. polyproprlene 100 parts
styrene-sodium maleate copolymer3 parts
styrene-calcium maleate copolymer1 part
C. polyethylene 100 parts
styrene-methyl methacrylate-
sodium maleate copolymer10 parts
sodium dodecylbenzene sulfonate3 parts
calcium stearate 2 parts
D. polypropylene 80 parts
polyethylene 20 parts
polyvinyl alcohol 3 parts
~()S;~S19
saponified ethylene-vinyl
acetate copolymer 5 parts
styrene-methyl methacrylatelauryl
methacrylatesodium maleate copo-
lymer 3 parts
E. polypropylene 80 parts
polvethylene 20 parts
chlorinated polypropylene 15 parts
calcium sulfate 20 parts
ethylene-calcium acrylate copolymer 3 parts
sodium dodecylbenzene sulfonate 2 parts
F. polypropylene 65 parts
ethylene-sodium acrylate copolymer 15 parts
styrene-methyl methacrylate-sodium
maleate copolymer 3 parts
styrene-methyl methacrylate_calcium
maleate copolymer 1 part
. polyethylene 100 parts
calcium carbonate 20 parts
saponified ethylene-vinyl acetate
copolymer 5 parts
styrene-octene-sodium maleate
copolymer 3 parts
H. polypropylene 80 parts
styrene-maleic anhydride copolymer 10 parts
sodium dodecylbenzene sulfonate 3 parts
calcium dodecylbenzene sulfonate 2 parts
I. polypropylene 100 parts
styrene-grafted polyvinyl alcohol 10 parts
J. polypropylene lOO parts
polyvinyl a~cohol 5 parts
styrene-grafted polyvinyl alcohol 5 parts
-- 8 --
105'~5~L9
The emulsified dispersion is heated to a temperature which is suffi-
cient to dissolve the polymers in the solvent and then to cause removal of the
solvent by vaporization from the polymer on extrusion. The preferred extrusion
temperature is from about 100C to 200C. Above about 200C, the emulsified
dispersion tends to lose stability and it is more difficult to obtain a desir-
able, fibrous material. Moreover, it is disadvantageous economically.
The emulsion flash-spinning can be conveniently carried out at auto-
genous pressure or at a pressure above autogenous pressure, to obtain a high
production rate. The dispersion and its vessel may be kept under pressure by
gaseous materials such as hydrogen, nitrogen, argon, carbon dioxide, methane,
ethylene or propylene, for example. The ejection is usually carried out at a
pressure of from about 5 to 100 kg/cm .
When the fibrous paper-forming material is produced by the present
method, the shape of the extrusion nozæle is important for obtaining desirable
paper-forming fibers. When the dispersion is e~ected through the nozzle, the
dispersed phase is elongated by shear forces and the polymer in the dispersed
phase is molecularly oriented and intertwined. Then, solidification of the
polymer occurs concurrently with the removal of compatible solvent by evapor-
ation and/or cooling. This solvent removal takes place before significant un-
desirable relaxation of the polymer (which has a natural tendency to regain a
random conformation) occurs. This allows a retention of the orientation of
the paper-forming material. The extrusion nozzle may be circular or non-circu-
lar (e.g. rectangular) in cross-section. A nozzle diameter (inscribed circle)
from about 0.2 to 20 mm is preferred. When the nozzle diameter is less than
about 0.2 mm, the nozzle tends to be prone to blockage by dust. Moreover, the
attainable production rate is quite low.
When the diameter is larger than about 20 mm, it then becomes diffi-
cult to obtain desirable paper-forming fibers because it ~hen becomes difficult
to obtain effective molecular orientation of the polymer. The ratio of length
to diameter of the extrusion nozzle is from about 0.1 to 100, pre-
_g_
~VS'~5~L~
ferabl~ from about 0.2 to 10~
The process of the present emulsion-jetting method is further ex-
plained as follows A polymer mixture mainly composed of poly-d-olefin as
heretofore described, together with a solvent such as methylene chloride, a
dispersion medium such as water, a surface active agent and, if necessary, a
heat stabilizer and any other desired additives, is heated under strong agi-
tation and emulsifiedO The emulsified dispersion is extruded through the
nozzle.
The particle size of the emulsion varies under various conditions.
In general, it may be distributed between about 0.1 to about 100 microns.
The required orientation of the paper-forming material is initially produced
by expansion extrusion which elongates the dispersed phase. To retain this
orientation notwithstanding the natural tendency of the polymer to regain a
random conformation subsequent to jet-extrusion, the polymer must be solid-
ified quickly before undersirable relaxation occurs. This solidification
can be obtained by the quick removal of compatible solvent by evaporation
and/or cooling. It is desirable, therefore, to cause the dispersion to be
jetted at a temperature which is higher than the boiling point of the sol-
vent and/or the dispersion medium. The jet-extruded material in some cases
tends to have an appearance similar to a marshmallow or sanitary cotton be-
cause of the intertwining of the polymer in the jetting operation. This pro-
duct is, however, easily disintegrated by treatment in a refiner, beater or
the like, because it is not made up of continuous filaments but is an aggreg-
ation of short fibers.
After the synthetic paper-forming fibrous material is formed into
paper, either using or not using an internal sizing reagent, in the steps
from disintegrating to paper-forming, the resulting paper sheet is subjected
to size press coating with surface size press coating agents This method
of production is explained as follows. f/~sl
B After the fibrous material obtained by emulsion ~l*sh-spinning pro-
--10--
105'~5~9
cess is disintegrated using an apparatus such as a home mixer, a PFI mill, arefiner or beater, or the like, the resulting fibrous pulp-like material is
mixed with natural pulp and formed into paper containing both pulps.
In the case of internal sizing of the synthetic fibrous material
or a mixture thereof with natural pulp, the following processes can be applied:
(1) producing a pulp which is treated with an internal sizing agent after mix-
ing a synthetic fibrous material and a natural pulp, (2) producing a pulp which
is obtained by mixing a natural pulp with a synthetic fibrous material previous-
ly treated with an internal sizing agent, and either treating them with an
internal sizing agent or not, (3) producing a pulp which is obtained by mixing
a natural pulp with a synthetic fibrous material that is disintegrated in a
solution of an internal sizing agent, and either treating them with an internal
sizing agent or not. An anionic internal sizing agent can be fixed on the pulp
by adding aluminum sulfate to the pulp suspension. Any order of additives of
anionic internal sizing agent and aluminum sulfate can be adopted.
Internal sizing agents are uæed in an amount of about 0.5 - 10% by
weight to a mixture of a synthetic fibrous material and natural pulp. The
pulp concentration is more preferably about 0.01 - 10% by weight. After the
resulting wet sheet has been sub~ected to dehydration (pressure-10 kg/cm ) and
20 drying (for example, using an FC dryer, at a temperature of 80 - 120C), the
resulting dry sheet is coated with a surface size press coating agent represent-
ed by the formula I, II, III and/or IV, and/or a well known surface size press
coating agent in order to produce a paper sheet which has a higher surface
picking strength. The amount of the size press agent is about 0.1 _ 5 g/m2
based on the weight of the paper shee~. The degree of improvement of the sur-
face picking strength can be confirmed by a standard wax-picking test, an IGT
printability tester, an RI after-tack test~ etc.
Examples of well known sizing agents are shown as follows: polyvinyl
alcohol (PVA), carboxymethyl cellulose (CMC), methyl cellulose (MC),
B -11-
519
starch, glue, algin, wax emulsion, alkyl ketene dimer, rosin, montan wax,
silicone, asphalt, pitch, sodium silicate, casein, urea resin, melamin resin,
polyethylene imine, low cast bean gum, synthetic gum latex emulsion, polyvinyl
acetate emulsion and polyacrylamide and its copolymers.
The following examples illustrate the invention, In these trade
marks are in quotation marksO
Example 1
A mixture composed of 100 g of isotactic polypropylene powder hav-
ing an (~ ) value of 2.3 dl/g, 20 g of acrylonitrile-styrene copolymer (AN/ST
- 24/76 by weight), 5 g of sodium maleate-styrene-methyl methacrylate copo-
lymer (50~30/20 by molar ratio), 1.15 1 of methylene chloride and 1.4 1 of
water was heated to between 140 C and 150 C for 30 minutes with stirring
at 700 rpm inside a steel autoclave having an internal volume of 5 liters
and was emulsified. Subsequently, when the valve of a nozzle having a dia-
meter of 1.6 mm and a length of 1.0 mm as opened, the fibrous material was
jetted out under autogenous pressure (about 17 kg/cm2 gauge)u 42 g of ejec-
ted material (corresponding to 3 g of dry weight material) was easily dis-
integrated over a period of 5 minutes together with 750 ml of water in a mix-
er. During disintegration the slurry did not foam, even under strong agit-
ation.
0.6 g of dry weight of this fibrous material having good dispersing
properties together with 24 g of dry weight of cellulose pulp (mixture of
NBKP/LBKP = 2/8, Canadian Standard Freeness = 450 ml) was formed into a wet
hand sheet by Tappi Standard Method T.205 os - 71.
This wet sheet was dried for 2 minutes at 110 C in an FC Drying
Machine produced by Fu C. Manufacturing Co" Ltd., and then pressed by a roll
under a pressure of 40 kg/cm .
The paper sheet obtained had a wax-picking strength (Tappi T459
su-65) of 6A and an I.G.T, surface strength (Tappi T499 su-64) of 185 c~ secu
E~ample 2
A paper-forming material was obtained froma mixture composed of
-12-
l~SZ5~9
100 g of isotactic polypropylene powder having an (p~) value of 2.3 dl/g, 3 g
of sodium dodecylbenzene sulfonate, 2 g of calcium dodecylbenzene sulfonate,
1.15 1 of methylene chloride and 1.4 1 of water by the same procedure as is
described in Example 1.
When this fibrous material was disintegrated together with water in
a mixer, the resulting slurry foamed excessively and the fibers were apt to
float. Thus this material had poor dispersing properties and gave a paper
sheet (composed of 20% of the fibrous material and 80% of cellulose pulp)
having inferior unifo~mity. This paper sheet had a wax-picking strength of
under 2A.
Example 3
A paper-forming material was obtained from a mixture composed of
95 g of isotactic polypropylene powder having an (n) value of 2.3 dl/g~ 10 g
of ac~rlonitrile styrene copolymer (AN/ST = 24/76 by weightl, 7 g of styrene-
sodium maleate copolymer, 1.15 1 of methylene chloride and 1.4 1 of water by
the same procedure as is described in E~ample 1.
After disintegrating the paper-forming material in a mixer~ a paper
sheet composed of 2 parts of this material and 8 parts of cellulose pulp was
obtained by the same procedure as is described in Example 1.
This paper sheet has a wax_picking strength of 8A and an I.G.T.
surface strength of 232 cm/sec.
Example 4
A paper-fonning material was obtained from a mixture composed of
140 g of isotactic polypropylene powder having an (~ ? value of 1.7 dl/g, 3 g
of polyvinyl alcohol ("Gosenol HM 14," manufactured by Nippon Gosei Chemical
Co., Ltd.~ Japan)~ 7 g of sodium, butyl maleate-styrene-methyl methacrylate
copolymer (50/30/20 in molar ratio), 1.15 1 of pentane and 1.4 1 of water by
the same procedure as is described in Example 1.
After disintegrating the paper-forming material in a mixer, a paper
sheet (composed of this material only) having a breaking length of 2.5 km
_ 13 --
lC~SZSl9
was obtained.
~xample 5
A paper-forming material was obtained from a mixture composed of
120 g of isotactic polypropylene powder having an ( ~ value of 1.7 dl/g, 3
g of polyvinyl alcohol, 5 g of sodium maleate-octene copolymer, 2 g of sodium
polypropylene glycol (30)-ethylene oxide (10) phosphate, 1,15 1 of hexane and
1.4 1 of water by the same method as is described in Example 1.
After disintegrating the m~terial in a mixer, a paper sheet (com-
posed of the synthetic pulp onlg) had a breaking length of 2.3 km and a paper
sheet (composed of 2 parts of the synthetic pulp and 8 parts of cellulose
pulp) h~d a breaking length of 3.6 kmO
Example 6
B A mixture 100 g of polyethylene powder ("Hizex 2100 LP", produced
by Mitsui Petro. Chem. Co., Ltd., Japan), 30 g of calcium carbonate, 3 g of
sodium maleate-styrene-methyl methacrylate-lauryl methacrylate copolymer (S0/
30/lS/lS in molar ratio), 1 g of calcium maleate-styrene-methyl methacrylate-
lauryl methacrylate copolymer ~50/30/15/15 in molar ration), 1.15 g of hexane
and 1.4 1 of water was emulsified and jetted out in the same procedure as is
described in Example 1.
The ejected material was easily disintegrated, and dispersed well
in ~ater. From this paper-forming material a paper sheet (composed of syn-
thetic pulp only) had a breaking length of S km and a paper sheet (composed
of 2 parts of synthetic pulp and 8 parts of cellulose pulp) had a wax-picking
strength of 7A.
Example 7
In a 2-liter four-necked flask equipped with a stirrer, a condenser
and two dropping funnels was placed a solution of 100 g of polyvinyl alcohol
("Gosenol NM 14t', manufactured by ~ippon Gosei Chemical Co~, Ltd., Japan) in
1 1 of water under nitrogen atmosphereu Under stirring this solution at 60
C 100 g of styrene monomer and a solution of 2~28 g of ammonium persulfate in
~ra ~e nha r ~
-14-
105~5~9
100 ml of water were added trhough funnels over a period of 1 hourO After
the addition of styrene and ammonium persulfate the reaction mixture was
stirred at 60 C for 4 hours.
A portion of the reaction mixture was poured into a large excess
of methanolO The poly~er coagulated was filtered and then washed in methan-
ol several timesO Conversion of styrene was about 100% and the grafted poly-
styrene in polym~rized styrene (which was not extracted by boiling benzene)
was about 78%o
A mixture composed of 6 g of styrene-grafted polyvinyl alcohol ob-
tained by the above procedure (used without isolation from the reaction mix-
ture), 94 g of isotactic polypropylene powder having an (~ ) value of 2 3
dl/g, 0O5 g of 2,6-di-t-butyl-4-methyl phenol, lolS 1 of methylene chloride
and 1038 1 of water was heated to 140 C with stirring at 700 rpm inside a
steel autoclave having an internal volume of 5 liters, and was emulsifiedO
Subsequently, when the valve of a nozzle having a diameter of 106 mm was
opened, the fibrous material was jetted out under autogenous pressure (about
17 kg/cm gauge). 40 g of ejected material (corresponding to 3 g of dry
weight material~ was disintegrated over a period of 5 minutes together with
750 ml of water in a mixerO This disintegrated fibrous material was gather-
ed on 200 mesh wire through 14 mesh wire in a pulp classifier (produced by
Kumagaya Riki CoO~ Ltdo). In the classifier the fibrous material was dis-
persed well in waterO This pulp slurry did not foam during agitationO
006 g dry weight of this fibrous material having good dispersing
properties, together with 204 g of dry weight of cellulose pulp (mixture of
NBKP/LBKP = 2/8, Canadian Standard Freeness 450 ml) was formed into a wet
hand sheet by Tappi Standar~ Method To205 05-710 This wet sheet was dried
for 2 minutes at 110 C in an FC Drying Machine produced by Fo CO Manufactur-
ing CoO~ Ltd., and then pressed by a roll under a pressure of 40 kg/cm2.
The paper sheet obtained had a basis weight of 5205 g/m2, a bright-
ness of 8505%, an opacity of 7702%, a breaking length of 4.14 km and an IGT
-15-
lOS'~519
surface strength of 160 cm/secO
E~am~le 8
A mixture of 94 g of isotactic polypropylene powder having an (~ )
value of 203 dl/g, 3 g of polyvinyl alcohol ('IGosenol NM 14~), 3 g of sodium
dodecylbenzene sulfonate, 0.5 g of a, 6-di-t-butyl-4-methyl phenol, 1015 1
of methylene chloride and 1.38 1 of water was heated to 140 C with stirring
at 700 rpm inside a steel autoclave having an internal volume of 5 liters
and was emulsifiedO Subsequently, when the valve of a nozzle having a dia-
meter of 106 mm was opened, the fibrous material was jetted out under auto-
genous pressureO When 40 g of ejected material (corresponding to 3 g of dry
weight material) was disintegrated over a period of 5 minutes together with
750 ml of water in a mixer, the pulp slurry foamed heavily.
After this slurry was poured into a pulp classifier, the foam was
hard to disperse and the fibrous material readily floated and was not disper-
sed well in the water.
In this case, the paper sheet composed of a mixture of 2 parts of
a fibrous material and 8 ~arts of cellulose pulp (NBKP/LBKP = 2/8, CSF 450
ml) obtained by the same procedure as is mentioned in Example 7 had a basis
weight of 5105 g/m 9 a brightness of 8600%, an opacity of 8000%, a breaking
length of 285 km and an IGT surface strength of 20 cm/sec~
Examples 9 - 13
Several vinyl-monomer-grafted polyvinyl alcohols obtained by the
same procedure mentioned in Example 7 are shown in Table lo
-16-
105;~5~9
Table 1
Sample PVA used Grafted Feed monomer Uonomer Monommr
NoO monomer PVA Conver- Graft
. . i 1. aion Efficiency
A "Gosenol NM 14" Styrene 2/1~ 100 35
B t'Gosenol NL 05" Styrene 1/1100 45
C "Gosenol KH 17" Styrene 1/1100 90
D "Gosenol NM 14" ~ethyl meth- 1/1 100 68
acrylate
E "Gosenol ~3 14" IStyrene V2 100 70 .
Using these vinyl-monomer-grafted polyvinyl alcohols, emulsion
flash-spinning was carried out, using the same procedure mentioned in Fxample
7. The properties of the paper-forming fibrous materials obtained are shown
in Table 2.
Table 2
~un Grafted Spinning Composition ¦ Foaming ~ Paper Sheet
No. PVA used
PP Grafted PVA Breaking IGT sur-
Length face
_ _ _ km stren_~
9 ~ 1) 90 10 None 3.56 115
Bl~ 85 15 None 3.87 231
11 cl) 90 10 None 3.74 150
12 Dl) 70 10 None 3.81 142
13 El) _ 90 10 Trace 3.90 161
1) corresponding to Table 5.
Example 14
A mixture of 70 g of isotactic polypropylene powder having an (~ )
value of 2.3 dl/g, 1 g of polyvinyl alcohol ('`Gosenol NH 18" s), 20 g of ethy-
-17-
~05'~519
lene-vinyl acetate copolymer ("Evaflex 560"~ Mitsui Polychem Co.~ Ltd., Japan),
3 g of styrene-methyl methacrylate-lauryl methacrylate-sodium maleate copolymer
(30/15/5/50 in molar ratio), styrene-methyl methacrylate-lauryl methacrylate-
calcium maleate copolymer (30/15/5/50 in molar ratio), 1.15 1 of hexane and
1.4 1 of water was emulsified and jetted out by the same procedure as is des-
cribed in E~ample 1.
The ejected material was disintegrated together with water in a mi~er.
The synthetic pulp obtained was formed into a paper hand sheet and
either treated or not treated with internal sizing agents.
The surface strengths of paper sheets composed of 2 parts of synthe-
tic pulp and 8 parts of cellulose pulp are shown in Table 3.
As is shown in Table 3, the sur~ace strength was much improved by the
use of à combination internal sizing and size pressing with polyvinyl alcoholO
Table 3
1) ' , .
Internal Size p~ess 2) Wax-picking
Sizing (g/m ) Strength
_ , ~ l
None 0 2A
None 0.9 5A
II-a33) 4) 1~0 48A
Polyethylene-imine 0 2-3A
Polyethylene-imine 1 0.3 L
1) The amount of sizing agents was 3~2% by weight based on a synthetic
pulp D
2) Polyvinyl alcohol (Gosenol NH- 33) was used.
3) Styrene-methyl methacrylate-lauryl methacrylate-sodium maleate copolymer
(30/15/5/50 in molar ratio).
4) Polyethylene imine "P-1000", produced by Nippon Shokufai Chemical Co.,
Ltdo
t ~ rn~r~ -18
1052~;19
Example 15
A mixture composed of 62 g of polypropylene powder having an ~ )
value of 203 dl/g, 3 g of polyvinyl alcohol ("Gosenol NH-185"), 18 g of ethy-
B lene-sodium acryla~e copolymer ("Surlyn A", produced by DuPont), 3 g of styrene-
methyl methacrylate-sodium maleate copolymcr (30/20/50 in molar ratio) and
1 g of styrenemethyl methacrylate-calcium maleate copolymer, 1015 1 of hexane
and 104 1 of water was emulsified and jetted out by the same procedure as is
described in EXample lo
The ejected material was disintegrated together with water in a mix-
er. The synthetic pulp obtained was formed into a paper sheet together with
cellulose pulp after being treated with an internal sizing agent.
Surface strength of paper sheets composed of 2 parts of syntheticpulp and 8 parts of cellulose pulp is shown in Table 4.
Table 4
Internal ) Size Press Surface Strength
Sizing ~ _
Agent Amou~t Wax IGT
g/m (c ~sec)
None None None 4A 120
None PV~ 1.5 7A
I-a ) None None 7A
I-a ) PVA 1.0 8A > 390
I-a ) Cationic 0 35 7-8A
I-a ) "Polywax" 0.48 8A
I-a ) "Polystrone" 0.2 8A
_ - PVA 1O3 8A > 390
1) 3v3% of sizing agents and 4~0 of aluminum sulfate (by weight based
on the synthetic pulp) wære used.
~ tra~Je rn~ s
--19--
105;~5~9
2) The same agent as is shown in Table 3.
3) Styrene-methyl methacrylate sodium maleate copolymer (30/20/50 in
molar ratio).
4) "Saiden Glue KS-ltt, produced by Saiden Chemical Co., Ltd.
5) Calcium salt of polyacrylic acid, produced by Asada Chemical Co.,
Ltd.
6) Produced by Arabawa Rinsan Co., Ltd.
Example 16
A mixture composed of 70 g of isotactic polypropylene powder having
an (~ ) value of 2.3 dl/g, 3 g of polyvinyl alcohol ("Gosenol NH-185"), 3 g
of sodium dodecylbenzene sulfonate, 2 g of calcium dodecylbenzene sulfonate,
1.15 1 of hexane and 1.4 1 of water was emulsified and jetted out by the same
procedure as is described in Example 1.
The ejected material was disintegrated together with water in a mixerO
m e synthetic pulp obtained was formed into a paper sheet after treat-
ment with internal sizing agents. The surface strength of paper sheets compos-
ed of 2 parts of synthetic pulp and 8 parts of cellulose pulp is shown in Table
5.
In this case the surface strength was not improved remarkably by siz-
ing.
Table 5
Inter~ 1 )3~iz mgSize4 pres~Wax-picking strength
I-a % PVA ) g/m
~.
None None ~ 2A
None 0.6 3A
3 None ~ 2A
3 0.8 4A
6 None c~ 2A
6 1.3 3A
. _ ,
'tr~e ~rl~
-20-
~os~s~9
) 107% (based on the synthetic pulp) was also used.
2) The sam~ agent as is shown in Table 3O
3) Based on the synthetic pulp.
4) "Gosenol NH-33".
Example 17
A mixture composed of 100 g of polyethylene (Hizex 2100 LP), 3 g
of polyvinyl alcohol ('IGosenol NH-185"), 20 g of calcium carbonate, 3 g of
styrene-methyl methacrylate-lauryl methacrylate-sodium maleate copolymer
(30/15/5/50 in molar ratio), 1 g of styrene-methyl methacrylate-lauryl metha-
10 crylate-calcium maleate copolymer (30/15/5/50 in molar ratio), 1015 1 of hex-
ane and 1.4 1 of water was emulsified and jetted out by the same procedure as
is described in Example 1,
The ejected material was disintegrated in the refiner.
The synthetic pulp obtained was formed into a paper sheet after
being treated with internal sizing agents.
The surface strength of paper sheets composed of 2 parts of the
synthetic pulp and 8 parts of cellulose pulp is shown in Table 6.
Table 6
Internal sizing ) Size press 22) Wax-picking
agent amount g/m strength
None None 6A
None 1.5 llA
vàtionic starch ) None 7-8A
pationic starch ) 1~4 11-12A
R ~Zeikthene AS~ None 7A
'Zeikthene AS" loO lOA
'Polywàx" None 6-7A
'Polywa~" ) 1.4 lOA
'Polyacrone''5) None 6-7A
'Polyacrone" ) 1.0 11-12A
I-à3) None 6-A
I-a ) 1.0 lOA
. , . _
ra J e~ /n a r~s 2:1
105'~519
1) 303% of si~ing agent 1.7% of aluminum sulfate (based on the synthetic
pulp) were used.
2) Polyvinyl alcohol ("Gosenol NH-33") was used.
3) Table 4 should be referred toO
4) Seitetsu Chemical Co., Ltd.
5) Hamano Chemical Co., Ltd.
-22-
