Process for the preparation of fibers from polymeric materials

Polyolefin fibers, which are suited for at least partially substituting the cellulose fibers in the manufacture of paper, are produced by a process which consists in preparing in a pressure vessel a solution of a polyolefin at a temperature higher than the boiling temperature of the solvent under normal conditions, and under autogenous pressure or a pressure greater than the autogenous pressure, in ejecting said solution under the above stated conditions into a zone of lower pressure, in allowing the ejected solution to expand at least partially in said zone, and in then hitting the at least partially expanded solution with a jet of a high-speed fluid, which is at a temperature lower than that of the solution, and has an angled direction with respect to the direction of ejection of the solution.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to the field of fibers of synthetic polymer 
materials, which are suited for replacing the cellulose fibers in the 
manufacture of paper. 
2. Description of the Prior Art 
The production of fibers of synthetic polymer materials, having such 
characteristics as to be suited, without previous cutting or disgregating 
operations, for replacing at least partially the cellulose fibers in the 
manufacture of paper, is known. 
However, the various methods which have been employed in the past for said 
production, proved to be so expensive as to make of the preparation of 
paper from such fibers an unprofitable proposition. 
Thus, in U.S. Pat. Nos. 2,999,788 and 2,988,782 there are described 
processes for the preparation of fibrous particles of a very thin 
thickness and 10 to 100.mu. in length, commonly called fibrils or fibrids, 
which processes consist in gradually adding a synthetic polymer solution 
to precipitating agents for the polymer, under simultaneous heavy 
stirring. This process is however limited to the use of condensation 
polymers; moreover the microfibers thus prepared, due to their high cost, 
do not find a practical use, in spite of their interesting 
characteristics. 
Quite recently there was suggested the preparation of fibrils of olefin 
polymers directly during the polymerization of the monomers (reactor 
fibers), this latter being carried out in the presence of suitable 
solvents and by keeping up a stirring exerting high shearing forces. 
A process of this type is disclosed in British Pat. No. 1,287,917. The 
fibrils obtained through it, with a length varying from a few tenths of a 
micron to some millimeters, are particularly suited for being incorporated 
in the paper pulps in various percentages, and their characteristics allow 
their treatment by means of the standard paper processing machinary. The 
process herein above described has, however, the drawback of requiring 
special reactors expressly designed for this process (since the standard 
reactors for the polymerization of olefins are unsuited for the purpose) 
and only useable for this particular production. 
SUMMARY OF THE INVENTION 
I have discovered that polyolefin fibers, directly suited for replacing at 
least partially the cellulose fibers in the manufacture of paper, may be 
very economically obtained by a process which consists in preparing a 
solution of a polyolefin, at a temperature higher than the boiling 
temperature of the solvent under normal conditions, and under the 
autogeneous pressure or a pressure greater than the autogeneous one, in 
ejecting said solution, under the above stated conditions, through a 
nozzle, into a zone of lower pressure, in allowing the ejected solution to 
expand at least partially in such zone, and in then hitting the at least 
partially expanded solution with a jet of a high-speed fluid which is at a 
temperature lower than that of the solution and has an angled direction 
with respect to the direction of ejection of the solution. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Crystalline polyolefins, obtained by homo- or copolymerization of monomers 
having general formula: 
##STR1## 
such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, 
polystyrene, copolymers ethylene-propylene, and the like, may be used in 
the process of the present invention. 
Particularly interesting polymeric materials proved to be the linear 
polyethylene of the type that is obtained by means of supported Ziegler 
catalysts, such as those described for instance in Italian Pat. Nos. 
853,733, 853,734 and 860,130, the polypropylene essentially consisting of 
isotactic macromolecules, of the type that is obtained by means of 
Ziegler-Natta catalysts such as those described, for instance, in Italian 
Pat. No. 526,101, and mixture of said polyolefins with minor amounts of 
other polymers such as polyvinyl chloride, polyvinyl acetate, 
polymethylmethacrylate, polyamides, polyoxymethylene, cellulose acetate, 
etc. 
For preparing fibers endowed with a high cohesive power, there may be used 
polyolefins of the above indicated general formula, modified by 
introducing into them polar groups. 
It may be advisable though not indispensable that the solvent used in the 
solution shall have a boiling temperature lower than the melting 
temperature of the polymer. In general there may be used all those 
solvents, liquid or gaseous under normal conditions, that are suited for 
supplying homogeneous solutions of the polymer under operational 
conditions. 
Solvents suitable for use may be, for instance: aliphatic hydrocarbons such 
as n- or iso-butane, pentane, hexane, heptane, octane; cycloaliphatic 
hydrocarbons such as cyclohexane; aromatic hydrocarbons, such as benzene, 
toluene, xylene, chlorinated hydrocarbons such as chlorobenzene, 
trichloroethylene, tetrachloroethylene, trichlorofluoromethane. 
The process may be used by employing a wide range of concentrations of the 
polymeric solutions, also depending on the molecular weight and on the 
type of polymer used. In general there may be used solutions containing 
from 1 to 700 g/lt of polymer; for attaining best results it is advisable 
to use solutions containing from 50 to 400 g/lt of polymer. 
In general it was found that the best operational conditions, with regard 
to the obtention of fibers of homogeneous dimensions and usable in paper 
pulps without any particular processing, are those offered by the use of 
polymeric solutions having, under operational conditions, absolute 
viscosities like those found at 130.degree. C. in a solution obtained by 
dissolving in 1 lt of hexane 100 g of polyethylene having a [.eta.] in 
tetralin at 135.degree. C.=0.9. 
Pigments, fillers, stabilizing agents, antistatic agents and/or other 
substances suited for modifying the surface properties of the fibers, may 
be added to the polyolefin solutions. Particularly convenient proved to be 
the addition to the solution of surfactants, the fact which allows one to 
obtain fibers readily dispersible in water. The dispersibility in water of 
the fibers is a very important factor for their utilization in the 
preparation of paper according to conventional methods. The lack of 
hydrophile properties of the polyolefin fibers makes such a dispersion 
rather difficult in the preparatory stage of the aqueous stuff. On the 
other hand, the addition of the water of surfactant compounds before or 
during the dispersion operation of the fibers, involves certain drawbacks, 
such as for instance the formation of foam that causes the stratification 
of the synthetic material, when one operates, for instance, with mixes of 
polyolefinic fibers with cellulose fibers. The addition of a wetting agent 
directly to the polyolefinic solution before its extrusion, allows one to 
overcome such difficulties. 
The wetting or surfactant agent used, must be uniformly soluble or mixable 
in the solvent and in the polyolefin. It may indifferently be of the 
anionic, cationic, non-ionic, or amphoteric type. Amongst the surfactants 
of the anionic type, usable for the purpose, there may be cited, for 
instance, the soaps of fatty acids, the soaps of naphthenic acids, the 
salts of sulphuric acid esters, the alkaline sulphonates, the alkyl esters 
of phosphorous or phosphoric acids, the salts of alkyl-phosphoric esters, 
the sodium salts of the sulphuric esters of 
alkylphenolpolyethyleneglycole. 
As surfactants of the cationic type may be used, for instance, the 
quaternary ammonium alkyl compounds, the aliphatic amines, the basic salts 
of alkylpyridinium or of alkylpicolinium, as well as the alkylbenzimidazol 
derivatives. Examples of usable amphoteric surfactants are: the compounds 
of the betaine and of the sulpho-betaine type, as well as the amphoteric 
compounds of the group of sulphuric and phosphoric acid esters. Finally, 
as surfactants of the non-ionic type may be cited: the 
polyoxyethylene-alkyl esters and ethers, the polyoxyethylenalkyl-aryl 
esters, the esters of fatty acids with higher alcohols, the 
polyoxyethylen-alkyl-amines, the alkanol-amides of fatty acids, the block 
copolymers polyoxyethylene-polyoxypropylene and the 
polyoxyethylene-alkylthioethers. 
It is necessary that the surfactant used shall remain incorporated in the 
fiber or at least adhering to the surface of the latter as much as 
possible. For this purpose the surfactant should be selected from amongst 
those surfactants which have a boiling temperature higher than that of the 
solution at the moment of its ejection from the pressure vessel. By means 
of a suitable choice of the surfactant, it is thus possible to greatly 
improve the property of the fibers to form a suspension in the aqueous 
medium. At the same time it will be found that both the antistatic 
properties of the fibers as well as the surface characteristics of the 
sheets prepared from them, will be improved. 
The quantity of surfactant to be added to the polyolefin solution, for the 
purposes of this invention, must be greater than 0.05% by weight on the 
olefin polymer. However, in order to attain the best possible results, it 
is generally preferable to use the surfactant in a quantity exceeding 0.1% 
by weight on the polyolefin. 
For reasons of saving, the maximum quantity of surfactant that may be added 
to the polymeric solution in order to obtain best results, may be kept 
within the limit of 5% by weight on the polymer, since greater quantities 
of surfactant will not yield appreciable advantages as far as the 
dispersion of the fibers in water is concerned. 
The surfactant used according to this invention may be dissolved or 
dispersed in the organic solvent before, after or contemporaneously to the 
dissolving of the polyolefine in that solvent. 
The speed at which the solution of polyolefine material is ejected through 
the nozzle may vary from 1,000 to 200,000 m/hr, but preferably there are 
used speeds comprised between 1,500 and 50,000 m/hr. The solution to be 
ejected should have a temperature at least 40.degree. C., but by far more 
preferably 60.degree. C. higher than the boiling temperature of the 
solvent under normal conditions. In order to obtain fibers of the suited 
morphology, it is necessary that the high-speed fluid hits the polyolefin 
solution after this latter has at least partially expanded in the lower 
pressure ambient wherein it is ejected. This is generally attained by 
positioning the high-speed fluid nozzle in such a way that the fluid hits 
the solution when this latter is at a certain distance from its exit 
nozzle. Such distance depends mainly on the ejection speed of the 
solution, but under the preferred operational conditions of the process it 
may be estimated to range from 1.5 mm to 15 mm. 
As hitting fluid there may be used any liquid, gaseous or vaporized 
substance which be inert and under operational conditions has no 
dissolving effect on the polyolefine used, but that preferably be not 
mixable with the solvent of the polymeric solution. Water steam proved to 
be particularly suited for the purpose in as much as, in comparison with 
other usable fluids, it offers the further advantage of humidifying the 
fibers, thereby facilitating their gathering while eliminating the 
conflagration danger due to static electricity with which the fibers tend 
to charge themselves. However, use may be made of any optional fluid such 
as nitrogen, oxygen, carbon oxide, air, combustion gas, finely divided 
water, and mixtures thereof. 
The speed of the hitting fluid turned out to be very important in respect 
to the viscosity of the solution used or with regard to the speed with 
which this solution is ejected through the nozzle. It has been found that 
the best operational conditions are obtained when operating at an impact 
speed of the fluid comprised between 200 and 600 m/sec. It has been found 
that within the range of operational conditions described above, some 
fluids show optimal conditions of use thanks to which fibers are obtained 
that possess contemporaneously the length and length/diameter ratio most 
suited for a convenient substitution of the cellulose fibers in the 
preparation of paper. 
Said operational conditions refer to the values of the angle formed by the 
direction of the fluid jet with the direction of the solution; said values 
are comprised f.i. between 50.degree. and 55.degree. for nitrogen, between 
80.degree. and 85.degree. for carbon dioxide and for steam, and between 
40.degree. and 60.degree. for oxygen. According to one preferred form of 
embodiment of this invention, the mass of the hitting fluid is directed 
against the solution in the form of a mass which is geometrically co-axial 
with the nozzle ejecting the solution itself. When using such preferred 
procedures, very uniformly shaped fibers are obtained, the fact which is, 
amongst others, particularly useful for obtaining paper of good surface 
characteristics.

By reference to FIG. 1, the polymer suspension in the organic solvent is 
fed into the autoclave (2) fitted with a stirrer (3), through a pipe (1). 
The hitting fluid, fed through (4), is ejected by the nozzle (5) and hits 
the polymeric solution which is ejected from the autoclave through the 
nozzle (6). Nozzle (5) may be positioned differently with respect to 
nozzle (6) so that the fluid may hit the solution under different angles, 
and at different distances from nozzle (6). The fibers that are thus 
formed are then gathered in a collecting vessel (7). 
Referring to the device as illustraed in FIG. 3 there are shown two 
co-axial ducts (1) and (2), the first inside the other, intended 
respectively for the feeding of the polymeric solution and of the hitting 
fluid, said ducts terminating with nozzles (3) and (4). 
A trunco-conical shaped chamber (5) forms a zone of lower pressure with 
respect to the pressure conditions existing in nozzle (3) during 
operation, and in which there takes place the expansion of the solution. 
The terminal zones (6) and (7) of the walls of the two ducts are so 
configurated that the axis of the interspace (8), determined by said 
walls, will form with the axis of the nozzle (3), in the ejection 
direction, an angle .alpha. preferably comprised between about 30.degree. 
and 90.degree.. 
Operating with such a device, the solution will be thus surrounded and hit 
angularly in every point of it by the fluid ejected by nozzle (4). 
It is quite evident that by operating a suitable resizing of zones (6) and 
(7), and possibly of nozzle (4), the operational conditions object of this 
invention can be realized also by feeding duct (1) with the high-speed 
fluid, and duct (2) with the polymeric solution. 
In this case the fluid remains surrounded by the solution and hits this 
latter at an angle from the inside. 
Thus, amongst the possible devices suited for establishing one of the 
preferred conditions of the process, that with the co-axial nozzle proved 
to be particularly convenient, both for the considerable constructional 
compactness as well as for the fact that it is suited for realizing in two 
ways said conditions. 
The following examples are given for illustrating and not limiting the 
present invention. 
EXAMPLE NO. 1 
Into an Inox steel autoclave of 50 lt capacity, fitted with a jacket and a 
blade stirrer with a maximum revolving speed of 300 rev. p. min. (rpm), 
were loaded 30 liters of technical hexane and 2 kg of polyethylene 
obtained by means of supported Ziegler-type catalysts, and modified with 
propylene, said polyethylene having the following characteristics: melt 
index=0.021; [.eta.] in tetralin at 135.degree. C.=3.0; density==0.950; 
number of methyls per 100 carbon atoms=0.83; melting temperature (through 
DSC)=132.degree. C. 
The autoclave was then heated up by circulating steam in the jacket, until 
obtaining a solution under the following conditions: pressure=2.2 
kg/sq.cm; temperature of solution=108.degree. C. 
The solution was then ejected from the autoclave in the atmosphere through 
a circular nozzle of 2 mm diameter, under the above indicated temperature 
and pressure conditions at a flow rate of 50 lt/hr, and hit at a distance 
of 2.5 mm from said nozzle by a steam jet at a speed upon impact of 470 
m/sec., ejected from a 4 mm diameter nozzle arranged at a right angle with 
the solution nozzle. 
Thereby a mixture of steam, fibers and organic solvent was obtained, which 
through a duct was conveyed to a filter in which the moist fibers were 
separated from the mixture. 
The content in organic solvent of the fibers was less than 0.3% by weight. 
At the visual analysis under the VISOPAN microscope, the product proved to 
consist for about 50% of single fibers having a length comprised between 1 
and 10 mm and a diameter of between 5 and 50.mu., and for about 50% of 
single flat fibers rolled up on themselves and having a length of 1-10 mm, 
a width of 100-500.mu. and a thickness of 5-50.mu.. From specific surface 
measurements, obtained with a PERKIN ELMER Sorptometer by absorption of 
N.sub.2, the product as a whole proved to have a surface area below 1 
sq.mt/g. 
150 g of the fibers obtained were admixed to 350 g of RAUMA type cellulose 
in 25 lt of water. This mixture was thereupon refined in a 
Lorentzen-Wettres hollander and through the time there were repeatedly 
drawn samples of pulp with which, after suitable dilutions, were produced 
sheets by following the procedures commonly used, and using a laboratory 
sheet forming machine. The characteristics of the sheets thus obtained 
have been recorded on Table 1. 
EXAMPLE NO. 2 
Into the autoclave described in example 1 were loaded 30 lt of technical 
hexane and 3 kg of polyethylene of the type indicated in example 1. By 
introducing steam into the heating jacket, in the autoclave there was 
obtained a solution under the following operational conditions: 
pressure=2.4 kg/sq.cm 
temperature=104.degree. C. 
By means of the nozzle device described in example 1, the solution was then 
ejected from the autoclave (with a flow rate of 45 lt/hr) into atmospheric 
ambient and hit at a distance of 2.5 mm from the exit nozzle by a steam 
jet at a speed upon impact of 470 m/sec. 
The product gathered on the filter proved to consist for about 50% of 
single fibers having a length of 1-20 mm and a diameter of 5-50.mu. and 
for about 50% of single flat fibers rolled up on themselves and having a 
length of 1-20 mm, a width of 100-500.mu. and a thickness of 5-50.mu., 
with a superficial area below 1 sq.mt/g. 
150 g of this fibrous product were then admixed to 350 g of RAUMA cellulose 
in 25 lt of water and this mixture was then used for preparing sheets, 
following the same procedures as have been described in example 1. 
The characteristics of said sheets are recorded on Table 1. 
EXAMPLE NO. 3 
In the autoclave described in example 1 there was prepared a solution 
consisting of 30 lt of technical hexane and 2.5 kg of polyethylene of the 
same type as that of example 1. After heating the solution in the 
autoclave, the following conditions were found: 
pressure=2.2 kg/sq.cm 
temperature=103.degree. C. 
By means of the nozzle device described in example 1 the solution was then 
ejected from the autoclave with a flow rate of 60 lt/hr, and hit at a 
distance of 2 mm from the exit nozzle with a steam jet at a speed upon 
impact of 470 m/sec. 
The product that was gathered consisted for about 80% of single fibers from 
1 to 5 mm long and with a diameter of from 5 to 20.mu., and for about 20% 
of single flat fibers rolled up on themselves and having a length of 1-5 
mm, a width of 50-100.mu. and a thickness of between 5 and 20.mu., its 
surface area being of about 1 sq.mt/g. 
A series of mixtures was then prepared, consisting of 120 g of above said 
product and of 280 g of cellulose of the respective types RAUMA, Birch, 
Modo and Kraft, in 20 lt of water. These mixtures were used for preparing 
sheets by following the procedures described in example 1. The 
characteristics of the sheets obtained have been recorded on Table 2. 
EXAMPLE NO. 4 
In the same autoclave of example 1 and maintaining the following 
conditions: 
pressure=14.5 kg/sq.cm 
temperature=134.degree. C., 
there was prepared a solution consisting of 30 lt of trichlorofluoromethane 
and of 3 kg of polyethylene obtained with supported Ziegler catalysts, 
said polyethylene showing the following characteristics: melt index=18.5; 
[.eta.] in tetralin at 135.degree. C.=0.9; density=0.952; number of 
methyls per 100 carbon atoms=0.65; melt temperature (by DSC)=130.degree. 
C. 
By means of the same nozzle device described in example 1, said solution 
was ejected from the autoclave into atmospheric ambient at a flow rate of 
90 lt/hr, and hit at a distance of 3 mm from the exit with a steam jet at 
impact speed of 470 mt/sec. Thereby was obtained a fibrous product 
consisting for about 80% of single fibers with a length of from 1 to 3 mm 
and a diameter of from 5 to 15.mu., and for about 20% of single flat 
fibers rolled up on themselves and having a length of between 1 and 3 mm, 
a width of between 50 and 100.mu. and a thickness of between 5 and 15.mu., 
while the surface area of this product amounted to 2 sq.mt/g. Starting 
from a mixture of 150 g of the product obtained with 350 g of RAUMA 
cellulose in 25 lt of water, and by following the procedures described in 
example 1, sheets were prepared whose characteristics have been recorded 
on Table 1. 
EXAMPLE NO. 5 
In the same autoclave as that described in example 1 and maintaining the 
following conditions: 
pressure=5.1 kg/sq.cm 
temperature=137.degree. C. 
a solution was prepared consisting of 30 lt of technical hexane and of 3 kg 
of polyethylene obtained with Ziegler-type supported catalysts, said 
polyethylene showing the following characteristics: melt index=18; [.eta.] 
in tetralin at 135.degree. C.=0.9; density=0.962; number of methyls per 
100 carbon atoms=0.21, and melt temperature (with DSC) of 131.5.degree. C. 
By using the nozzle device of the example 1, but with the nozzles arranged 
as to form an angle of 85.degree. the solution was ejected from the 
autoclave into atmospheric ambient at a flow rate of 95 lt/hr, and hit at 
a distance of 3 mm from the exit nozzle by a CO.sub.2 jet at room 
temperature and at a speed upon impact of 220 m/sec. The product thus 
obtained consisted for about 90% of single fibers with a length comprised 
between 2 and 4 mm and a diameter of about 5.mu., and for about 10 % of 
flat fibers having a length of 2-4 mm, a width of about 50.mu. and a 
thickness of about 5.mu., while its surface area amounted to 3.5 sq.mt/g. 
EXAMPLE NO. 6 
In the same autoclave of example 1 and maintaining the following 
conditions: 
pressure=4.8 kg/sq.cm 
temperature=135.degree. C. 
there was prepared a solution consisting of 30 lt of technical hexane and 
3.5 kg of polyethylene obtained with Ziegler-type supported catalysts, 
said polyethylene having the following characteristics: melt index=49; 
[.eta.] in tetralin at 135.degree. C.=0.9; density=0.952; number of 
methyls per 100 carbon atoms=0.28, and melt temperature (by 
DSC)=131.degree. C. For carrying out the process, the same nozzle device 
described in example 1 was used, with the exception that the single formed 
by the two nozzles was 85.degree.. The solution was ejected into the 
atmospheric ambient and hit at a distance of 2,5 mm from the ejcting 
nozzle by a steam jet. The formation conditions for the fibers are the 
following: 
flow rate of the ejected solution=55 lt/hr 
impact speed of steam=320 m/sec. 
The thus obtained fibrous product consisted for about 70% of single fibers 
with a length of 2-5 mm and a diameter of from 1 to 5.mu., and for about 
30% of single flat fibers having a length of 2-5 mm, a width of 50-100.mu. 
and a thickness of 1-5.mu., while its surface area mounted to about 3 
sq.mt/g. 
Starting from a mixture of 150 g of the obtained product with 350 g of 
cellulose (60% Birch, 20% Modo and 20% Kraft), and by following the 
procedures of example 1, sheets were prepared having the characteristics 
reported by Table 3. 
EXAMPLE NO. 7 
In the autoclave of example 1 and maintaining the following conditions: 
pressure=5.9 kg/sq.cm 
temperature=160.degree. C. 
a solution was prepared consisting of 30 lt of technical hexane and of 4.8 
kg of polyethylene of example 6. For carrying out the process the same 
nozzle device as that described in example 1 was used, but with the 
nozzles arranged to form an angle of 80.degree.. The solution was ejected 
into the atmospheric ambient and hit at a distance of 3.5 mm from the 
nozzle by a steam jet. 
The operational conditions for producing the fibers were: 
flow rate of the ejected solution=125 lt/hr 
impact speed of steam jet=320 m/sec. 
The product thus obtained consisted for about 80% of fibers with a length 
of 2-5 mm and a diameter of 1-5.mu., and for about 20% of flat fibers 
having a length 2-5 mm, a width of 50 to 100.mu. and a thickness of 
1-5.mu., while its surface area amounted to 5 sq.mt/g. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
cellulose (60% Birch, 20% Modo and 20% Kraft), and by following the 
procedures described in example 1, sheets were prepared whose 
characteristics have been recorded on Table 3. 
EXAMPLE NO. 8 
In the autoclave of example 1 and maintaining it there in at the following 
conditions: 
pressure=5.9 kg/sq.cm 
temperature=155.degree. C. 
a solution was prepared which conisted of 30 lt of technical hexane and of 
1.8 kg of polyethylene of the type of example 6. By using the nozzle 
device described in example 1, but with the nozzle arranged as to form an 
angle of 50.degree., the solution was ejected into the atmospheric ambient 
and hit at a distance of 3.5 mm from the ejecting nozzle by an oxygen jet 
at room temperature, under the following conditions: 
flow rate of solution: 120 lt/hr 
impact speed of oxygen jet: 470 m/sec. 
The product consisted almost entirely of single fibers having a length of 
about 4-5 mm and a diameter of about 5.mu.; the surface area mounted to 11 
sq.mt/g. The content in organic solvent of the fibers was less than 0.3% 
by weight. 
EXAMPLE NO. 9 
In the autoclave of example 1 and maintaining therein the following 
conditions: 
pressure: 5.5 kg/sq.cm 
temperature: 145.degree. C. 
there was prepared a solution consisting of 35 lt of technical hexane and 3 
kg of polyethylene obtained by means of supported Ziegler-catalysts, said 
polyethylene having the following characteristics: melt index=13.6; 
[.eta.] in teralin at 135.degree. C.=1; density=0.953; number of methyl 
groups per 100 carbon atoms=0.6 and melt temperature (by DSC)=130.degree. 
C. 
By using the nozzle device of example 1,(nozzles arranged at right angle) 
the solution was ejected into the atmospheric ambient and hit at a 
distance of 3 mm from the ejection nozzle by an oxygen jet at room 
temperature under the following conditions: 
flow rate of the ejected solution=100 lt/hr 
impact speed of oxygen jet=470 m/sec. 
The product proved to consist for about 80% of fibers 1 to 3 millimeter 
long and with a diameter of 5-20.mu., and for about 20% of flat fibers 1 
to 3 mm long, width comprised between 50 and 100.mu. and with a thickness 
of 50-20.mu.. The superficial area of the product amounted to 4 sq.mt/g. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
RAUMA cellulose, and by following the procedures described in example 1, 
sheets were prepared whose characteristics have been recorded on Table 4. 
EXAMPLE NO. 10 
In the autoclave of example 1 and by maintaining in it the following 
conditions: 
pressure=5.4 kg/sq.cm 
temperature=142.degree. C. 
there was prepared a solution consisting of 30 lt of technical hexane, 2.4 
kg of polyethylene of example 9 and of 0.6 kg of an ethylene-ethyl 
acrylate copolymer (Zetakin 80 of DOW CHEM.). By using the nozzle device 
of example 1 (nozzles at right angle), the solution was ejected into the 
atmospheric ambient and hit at a distance of 3 mm from the exit nozzle by 
a steam jet under the following conditions: 
flow rate of the ejected solution=100 lt/hr 
impact speed of steam jet=470 m/sec. 
The product proved to consist for about 80% of fibers 1-3 mm long and 
5-20.mu. in a diameter, and for about 20% of flat fibers 1-3 mm long, 
50-100.mu. wide and having a thickness of from 5 to 20.mu.; the surface 
area of said product amounted to 4 sq.mt/g and the density of the fibers 
amounted to 0.9450. Starting from a mixture of 150 g of the product 
obtained with 350 g of RAUMA cellulose, and by following the same 
procedures as those described in example 1, sheets were prepared whose 
characteristics have been recorded on Table 4. 
EXAMPLE NO. 11 
In the same autoclave of example 1 and maintaining in it the following 
conditions: 
pressure: 5.4 kg/sq.cm 
temperature: 139.degree. C. 
a solution was prepared that consisted of 35 lt of technical hexane, 2.55 
kg of the polyethylene of example 9 and of 0.45 kg of polyvinyl chloride 
(K value=45). By using the nozzles of example 1 arranged at right angle, 
the solution was ejected into the atmospheric ambient and here hit, at a 
distance of 4 mm from the ejecting nozzle, by a steam jet. The conditions 
used in the forming of the fibers were the following: 
flow rate of the ejected solution: 110 lt/hr 
impact speed of steam jet: 470 m/sec. 
The product proved to be constituted for about 85% of fibers 1-3 mm long 
and of 5-15.mu. in diameter, and for about 15% of flat fibers 1-3 mm long, 
50-100.mu. wide and with a thickness of from 5 to 15.mu.; its surface area 
amounted to 5.5 sq.mt/g. The density of the fibers was 0.9905. The content 
in organic solvent of the fibers was less than 0.3% by weight. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
RAUMA cellulose, and by following the procedures indicated in example 1, 
sheets were prepared whose characteristics have been recorded on Table 4. 
The preparation of the sheets was facilitated by the greater density of 
the fibrils. 
EXAMPLE NO. 12 
In the autoclave described in example 1 and by maintaining in it the 
following conditions: 
pressure: 3.4 kg/sq.cm 
temperature: 124.degree. C. 
a solution was prepared which consisted of 35 lt of technical hexane and 3 
kg of the polyethylene of example 9, to which was added 3% by weight of 
TiO.sub.2 on the polyethylene. By using the nozzle device of example 1 but 
with the nozzles arranged to form an angle of 50.degree., the solution was 
ejected into the atmospheric ambient and hit, at a distance of 5 mm from 
the ejecting nozzle, by a nitrogen jet at room temperature under the 
following conditions: 
flow rate of the ejected solution: 95 lt/hr 
impact speed of nitrogen jet: 470 m/sec. 
The product proved to consist for about 80% of fibers 2-4 mm long and 
1-5.mu. in diameter, and for 20% of flat fibers 2-4 mm long, 50-100.mu. 
wide and 1-5.mu. in diameter. The superficial area of the product amounted 
to 3.5 sq.mt/g, while the density of the fibers was 0.98. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
RAUMA cellulose, and by following the procedures described in example 1, 
sheets were prepared whose characteristics have been recorded on Table 4. 
EXAMPLE NO. 13 
In the autoclave described in example 1 and by maintaining in it the 
following conditions: 
pressure: 5.5 kg/sq.cm 
temperature: 163.degree. C. 
a solution was prepared that consisted of 30 lt of technical hexane, 2.1 kg 
of a polypropylene of a high isotactic index obtained by means of 
Ziegler-type catalysts, and which showed the following characteristics: 
melt index: 6.7 
density: 0.9085 
melt temperature (DSC): 165.degree. C. 
By using the nozzles of example 1, but arranged as to form an angle of 
70.degree., the solution was ejected into the atmospheric ambient and hit 
at a distance of 7 mm from the ejecting nozzle by a steam jet under the 
following conditions: 
flow rate of the ejected solution: 40 lt/hr 
impact speed of steam jet: 470 m/sec. 
The product proved to consist almost completely of fibers 1-5 mm long and 
5-20.mu. in diameter. The surface area of the product amounted to 7 
sq.mt/g. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
cellulose (60% Birch, 20% Modo and 20% Kraft), and by following the 
procedures described in example 1, sheets were prepared whose 
characteristics have been recorded on Table 5. 
EXAMPLE NO. 14 
In the autocalve described in example 1, and by maintaining in it the 
following conditions: 
pressure: 4.5 kg/sq.cm 
temperature: 155.degree. C. 
a solution was prepared consisting of 30 lt of technical hexane and 3 kg of 
low-density polyethylene, said polyethylene having the following 
characteristics: 
melt index: 4.6 
density: 0.9235 
melting temperature (DSC): 118.degree. C. 
By using the nozzle device of example 1, but with the nozzles arranged to 
form an angle of 60.degree., the solution was ejected into the atmospheric 
ambient and hit at a distance of 7 mm from the ejecting nozzle, by a 
nitrogen jet at room temperature, under the following conditions: 
flow rate of the ejected solution: 30 lt/hr 
impact speed of nitrogen jet: 470 m/sec. 
The product thus obtained consisted essentially of fibers 1-3 mm long and 
5-15.mu. in diameter. The surface area amounted to 13 sq.mt/g. The content 
in organic solvent of the fibers was less than 0.3% by weight. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
cellulose (60% Birch, 20% Modo and 20% Kraft), and by following the 
procedures described in example 1, sheets were prepared whose 
characteristics have been recorded on Table 5. 
EXAMPLE NO. 15 
In the same autoclave of example 1 and by maintaining in it the following 
conditions: 
pressure=3.0 kg/sq.cm 
temperature=140.degree. C. 
a solution was prepared which consisted of 30 lt of technical hexane, and 
2.1 kg of a polyethylene obtained with Ziegler-type unsupported catalysts, 
and which had the following characteristics: 
melt index=0.47; 
density=0.9603; 
number of methyl groups per 100 carbon atoms &lt;0.1, and melting 
temperature=134.degree. C. 
By using the nozzles of example 1, arranged as to form an angle of 
70.degree., the solution was ejected into the atmospheric ambient and hit, 
at a distance of 5 mm from the nozzle, by a CO.sub.2 jet at room 
temperature, under the following conditions: 
flow rate of the ejected solution=95 lt/hr 
impact speed of carbon dioxide jet=320 m/sec. 
The product obtained consisted for about 70% of fibers 1-10 mm long and 
5-20.mu. in diameter, and for about 30% of flat fibers 1-10 mm long, 
50-100.mu. wide and 5-20.mu. thick. The surface area mounted to about 2 
sq.mt/g. 
Starting from a mixture of 150 g of the product obtained with 350 g of 
cellulose (60% Birch, 20% Modo and 20% Kraft), and by following the 
procedures described in example 1, sheets were prepared whose 
characteristics have been recorded on Table 5. 
EXAMPLE NO. 16 
In the autoclave described in example 1 was prepared a solution consisting 
of 30 lt of technical hexane and 3 kg of the polyethylene of example 5. 
After heating up the solution in the autoclave, the following conditions 
were found: 
pressure: 5.6 kg/sq.cm 
temperature: 132.degree. C. 
By using the nozzle device of example 1 (nozzles at right angle) the 
solution was ejected into the atmosphere and hhit, at a distance of 5 mm 
from the ejecting nozzle, by a steam jet under the following conditions: 
flow rate of solution=90 lt/hr 
impact speed of steam jet=470 m/sec. 
The product obtained consisted for about 90% of single fibers from 1 to 3 
mm long and with a diameter of between 5 and 15.mu. and for about 10% of 
flat fibers rolled up on themselves and having a length of 1-3 mm, a width 
of about 50.mu. and a thickness of 5-15.mu.. Its surface area amounted to 
2,5 sq.mt/g. 
The preparation was repeated 6 (six) times so as to get 15 kg of product. 
12 kg of it were admixed to 27.6 kg of cellulose (60% Birch, 20% Modo and 
20% Kraft) and 9.5 kg of kaolin in about 1,200 lt of water. The mixture 
was then continuously refined in a conical refiner until reaching 
36.degree. SR, whereupon it was additioned with 0.08 kg of an optical 
bleacher (Calcofluor 4 MB), 0.8 kg of glue (Aquapel 360 XZ) and with 1.2 g 
of co-adjuvant (Kymene 557). To this mixture was then added water to 
double the volume of the suspension which was then transferred into the 
feeding vat of a continuous machine of the drum type, having a useful 
width of about 55 cm. There have thus been prepared 40 kg of paper whose 
characteristics have been reported on Table 6 (Test B) together with those 
obtained in a comparative test using only 40 kg of cellulose (60% Birch, 
20% Modo and 20% Kraft) (Test A). 
Part of the paper obtained from the pulp containing polyethylene fibers had 
been calendered between two rolls maintained at a temperature of about 
140.degree. C. and also the results of this operation have been recorded 
on the above mentioned table (Test C). 
The following examples illustrate the use of surfactants in the polyolefin 
solution. 
EXAMPLE NO. 17 
Into a 150 lt autoclave fitted with a heating sleeve and a blade stirrer, 
were loaded 6 kg of polyethylene having the following characteristics: 
melt index=4.1 
density=0.9633 
CH.sub.3 /100 C number=0.1 
melting temperature (DSC)=133.degree. C. 
together with 30 g of a surfactant consisting of an ethoxylated 
stearylamine and 70 lt of technical hexane. Using a heating with oil, the 
following conditions were established in the autoclave: 
temperature=150.degree. C. 
total pressure=7 kg/sq.cm 
nitrogen overpressure=1.6 kg/sq.cm 
By means of a pipe sheathed with a steam-heated sleeve, the solution was 
conveyed to a nozzle having a diameter of 2 mm, ejected through said 
nozzle into the outer atmospheric ambient, and hit, at a distance of 2.5 
mm from the ejection nozzle, by a nitrogen jet at room temperature, 
flowing from a second 4 mm diameter nozzle forming with the first nozzle 
an angle of 50.degree.. 
The operational conditions were as follows: 
temperature of the solution at the nozzle=158.degree. C. 
pressure of the solution at the nozzle=7,2 kg/sq.cm 
pressure of the nitrogen at the nozzle=21 kg/sq.cm 
flow rate of the solution-100 kg/hour 
impact speed of the nitrogen=320 m/sec. 
The product that was gathered, examined at a Vispan (Riechert) microscope, 
appeared to consist for 80% of fibers 2 to 5 mm long, and having a 
diameter of between 1 and 5.mu., and for 30% of flat fibers 2 to 5 mm 
long, 20 to 50.mu. wide and from 1 to 5.mu. thick, and to contain less 
than 0.3% by weight of solvent. 
The superficial area of the product, measured with a Perkin-Elmer 
Sorptometer, proved to be equal to 2.9 sq.mt/g. 
150 g of the fibers thus obtained were admixed with 350 g of cellulose (60% 
Husum Birch, 20% Husum Kraft and 20% Modo Crown) in 25 lt of water. The 
mixture dispersed itself immediately. 
The aqueous mixture was then refined in a Lorentzen-Wettres hollander and, 
after suitable dilution, used for producing sheets according to the 
procedures commonly used, by means of a laboratory sheet-forming machine. 
The characteristics of the sheets thus obtained have been recorded on 
Table 7. 
EXAMPLE NO. 18 
Into the autoclave of example 17 were loaded 6 kg of polyethylene of the 
same characteristics as that described in example 17, 30 g of a surfactant 
consisting of nonylphenol ethoxylate (molar ratio nonylphenol/ethylene 
oxide=1.6), and 70 lt of technical hexane. 
Using a heating with oil, in the autoclave were established the following 
conditions: 
temperature=155.degree. C. 
total pressure: 8.2 kg/sq.cm 
nitrogen overpressure=1.6 kg/sq.cm 
Using the same procedures and equipment described in example 17, but with 
the nozzles arranged to form an angle of 60.degree., the solution was 
ejected into the outer atmospheric ambient, hitting it, at a distance of 5 
mm from the ejection nozzle, with a nitrogen current at room temperature. 
The operational conditions were the following: 
temperature of solution at the nozzle=175.degree. C. 
diameter of solution ejecting nozzle=2 mm 
flow rate of solution=108 kg/hr 
pressure of solution at the nozzle=9 kg/sq.cm 
diameter of nitrogen ejecting nozzle=4 mm 
pressure of nitrogen at the nozzle=20 kg/sq.cm 
impact speed of the nitrogen=370 mt/sec. 
The product that was gathered, proved to consist for 80% of fibers from 1 
to 3 mm long and having a diameter of between 1 and 10.mu., and for 20% of 
flat fibers from 1 to 3 mm long, from 20 to 50.mu. wide and from 1 to 
10.mu. thick. 
The superficial area of the product amounted to 2.5 sq.m/g. 
150 g of the fibers thus obtained were admixed to 350 g of cellulose (60% 
Husum Birch, 20% Husum Kraft and 20% Modo Crown) in 25 lt of water. 
Thereby was obtained the immediate complete dispersion of the fibers in 
water. 
Starting from this aqueous mixture and following the same procedure as 
described in example 1, sheets were prepared that showed the 
characteristics recorded on Table 7. 
EXAMPLE NO. 19 
Into the autoclave of example 17 were loaded 6 kg of polyethylene of the 
same characteristics of the polyethylene described in example 17, 30 g of 
a surfactant consisting of nonylphenolethoxylate (1 mole of nonylphenol 
per 7.5 moles of ethylene oxide), and 70 lt of heptane. 
Using a heating with oil, the following conditions were established inside 
the autoclave: 
temperature=165.degree. C. 
total pressure=7.0 kg/sq.cm 
nitrogen overpressure=2 kg/sq.cm 
Using the procedures and equipment of example 17, but with the nozzles 
arranged to form an angle of 85.degree., the polymeric solution was 
ejected into the external atmospheric ambient, and hit at a distance of 5 
mm from the ejection nozzle with a flow of carbon dioxide at room 
temperature. 
The operational conditions were the following: 
temperature of the solution at the nozzle=172.degree. C. 
diameter of the solution ejecting nozzle=2 mm 
flow rate of the solution=100 kg/hr 
pressure of the solution at the nozzle=9.0 kg/sq.cm 
diameter of CO.sub.2 ejecting nozzle=4 mm 
pressure of CO.sub.2 at the nozzle=19 kg/sq.cm 
impact speed of CO.sub.2 =300 mt/sec. 
The product appeared to consist almost totally of fibers 2 to 5 mm long and 
having a diameter comprised between 1 and 5.mu.. The superficial area of 
the product amounted to 2.5 sq.mt/g. 
15 g of the thus obtained fibers were admixed to 350 g of cellulose (60% 
Husum Birch, 20% Modo Crown and 20% Husum Kraft) in 25 lt of water, 
thereby obtaining an immediate dispersion of the fibers. 
Following the procedures described in example 1, from this paste were 
prepared sheets whose characteristics have been recorded on Table 7. 
EXAMPLE NO. 20 
Into the autoclave of example 17 were loaded 6 kg of polyethylene having 
the same characteristics of that of example 17, 30 g of a surfactant 
consisting of a mixture of C.sub.10 -C.sub.12 alcohols ethoxylate with 
ethylene oxide (molar ratio of ethoxylation=1:2), and 70 lt of technical 
hexane. 
By using a heating with oil, the following conditions were established in 
the autoclave: 
temperature=172.degree. C. 
total pressure=12 kg/sq.cm 
nitrogen overpressure=3.5 kg/sq.cm 
Using the same procedures and equipment of the example 17, but with the 
nozzles arranged to form an angle of 65.degree., the polyethylene solution 
thus formed was conveyed to the ejection nozzle and the ejected jet was 
hit at a distance of about 3 mm from the nozzle by a nitrogen current at 
room temperature. 
The operational conditions were the following: 
temperature of the solution at the nozzle=190.degree. C. 
diameter of solution ejecting nozzle=2 mm 
flow rate of solution=105 kg/hr 
pressure of solution at the nozzle=12 kg/sq.cm 
diameter of the nitrogen ejecting nozzle=4 mm 
pressure of nitrogen at the nozzle=21 kg/sq.cm 
impact speed of the nitrogen=320 mt/sec. 
The product thus obtained appeared to consist completely of fibers from 1 
to 3 mm long and with a diameter of between 1 and 20.mu.. 
The supercial area of the product amounted to 4.5 sq.m/g. 
150 g of the fibers thus obtained were kneaded together with 350 g of 
cellulose (60% Husum Birch, 20% Husum Kraft and 20% Modo Crown) in 25 lt 
of water, thereby obtaining an instantaneous complete dispersion. 
Following then the procedures described in example 1, with this paste were 
prepared sheets whose characteristics have been recorded on Table 7. 
EXAMPLE NO. 21 
Into the autoclave of the example 17 were loaded 7 kg of a polyethylene 
having the same charcteristics as that of example 17, 3 kg of a calcined 
clay with 95% of its particles below 10.mu., 35 g of a surfactant 
consisting of the condensation product of a mole of stearic acid with 5.5 
moles of ethylene oxide, and 80 lt of technical hexane. By means of 
heating, the following conditions were established inside the autoclave: 
temperature=148.degree. C. 
total pressure=7.7 kg/sq.cm 
nitrogen overpressure=2.2 kg/sq.cm 
Using the same procedures and equipment of example 17, but with the nozzles 
arranged to form an angle of 55.degree., the mixture containing 
polyethylene in solution was ejected into the atmospheric ambient through 
a nozzle and hit at a distance of about 4 mm therefrom by an oxygen 
current at room temperature. The operational conditions were the 
following: 
temperature of the solution at the nozzle=151.degree. C. 
diameter of the solution ejecting nozzle=2 mm 
rate flow of solution=70 kg/hr 
pressure of the solution at the nozzle=6 kg/sq.cm 
diameter of the oxygen ejecting nozzle=4 mm 
pressure of the oxygen at the nozzle=21 kg/sq.cm 
impact speed of the oxygen=320 mt/sec. 
The product thus obtained consisted for 80% of fibers between 3 and 5 mm 
long and with a diameter of between 1 and 5 and for 20% of flat fibers 
from 3 to 5 mm long, 20 to 50.mu. wide and from 1 to 5.mu. thick. 
The superficial area of the product amounted to 2.5 sq.mt/g, while the 
density (at 23.degree. C.) was 1.163 g/cu.cm. 
150 g of the fibers thus obtained were kneaded together with 350 g of 
cellulose (60% Husum Birch, 20% Husum Kraft and 20% Modo Crown) in 25 lt 
of water, thereby obtaining an immediate complete dispersion. 
Using this paste, with the procedures of example 1, sheets were prepared 
whose characteristics have been recorded on Table 7. 
EXAMPLE NO. 22 
Into the same autoclave of example 17 were loaded 7 kg of a polyethylene of 
the same characteristics as that used in example 17, 3 kg of the clay 
described in example 21, 35 g of a surfactant consisting of monolauric 
ester of sorbitol and 80 lt of technical hexane. 
Through heating, in the autoclave were established the following 
operational conditions: 
temperature=147.degree. C. 
total pressure=8.7 kg/sq.cm 
nitrogen overpressure=3.5 kg/sq.cm 
Using the same procedures and the equipment of example 17, but with the 
nozzles arranged to form an angle of 70.degree., the mixture containing 
the polyethylene in solution was conveyed to the nozzle and ejected into 
the atmospheric ambient, where the jet was hit at a distance of about 4 mm 
from the nozzle by an oxygen flow at room temperature. 
The operational conditions were as follows: 
temperature of the solution at the nozzle=165.degree. C. 
diameter of the solution ejecting nozzle=2 mm 
flow rate of the solution=60 kg/hr 
pressure of the solution at the nozzle=8.3 kg/sq.cm 
diameter of the oxygen ejecting nozzle=4 mm 
pressure of the oxygen at the nozzle=20 kg/sq.cm 
impact speed of the oxygen=320 mt/sec. 
The product thus obtained consisted for 70% of fibers between 1 and 5 mm 
long and with a diameter between 1 and 20.mu. and for 30% of flat fibers 
from 1 to 5 mm long, from 20 to 50.mu. wide and from 1 to 20.mu. thick. 
The superficial area of the product was 2.5 sq.mt/g; while the density (at 
23.degree. C.) amounted to 1.166 g/cu.cm. 
A mixture consisting of 150 g of the fibers thus obtained together with 350 
g of cellulose (60% Husum Birch, 20% Husum Kraft and 20% Modo Crown) and 
kneaded in 25 lt of water, thereby obtaining an immediate complete 
dispersion. 
With the paste thus obtained and following the procedures described in 
example 1, sheets were therewith prepared whose characteristics have been 
recorded on Table 7. 
EXAMPLE NO. 23 
Into the same autoclave of example 17 were loaded 7 kg of a polyethylene of 
the same characteristics as that of example 17, 3 kg of calcined clay of 
example 21, 35 g of a surfactant consisting of a mixture of C.sub.10 
-C.sub.12 alcohols etoxylate with ethylene oxide (molar ratio of 
ethoxylation=1:5), and 80 lt of technical hexane. By heating, the 
following operational conditions were established in the autoclave: 
temperature=169.degree. C. 
total pressure=10.9 kg/sq.cm 
nitrogen overpressure=2.8 kg/sq.cm 
Through a pipe sheathed with a steam heated sleeve, the mixture was ejected 
into the atmospheric ambient through a nozzle and the outcoming jet was 
hit at a distance of about 2.5 mm from the ejection nozzle by a saturated 
steam jet coming out of a second nozzle arranged at an angle of 85.degree. 
with respect to the first nozzle. The operational conditions were the 
following: 
temperature of the solution at the nozzle=180.degree. C. 
diameter of the solution ejecting nozzle=2 mm 
flow rate of the solution=105 kg/hr 
pressure of the solution at the nozzle=11.5 kg/sq.cm 
diameter of the steam-ejecting nozzle=4 mm 
impact speed of the steam=450 m/sec. 
The thus obtained product consisted for 90% of fibers from 2 to 5 mm long 
and with a diameter of from 1 to 5.mu., and for 10% of flat fibers from 2 
to 5 mm long, from 20 to 50.mu. wide and from 1 to 5.mu. thick. 
The density (at 23.degree. C.) of the product amounted to 1.168 g/cu.cm. 
A mixture of 150 g of the fibers thus obtained with 350 g of cellulose (60% 
Husum Birch, 20% Husum Kraft and 20% Modo Crown) was kneaded with 25 lt of 
water, thereby achieving an immediate complete homogeneous dispersion. 
Using this paste and operating according to the procedures of example 1, 
sheets were prepared whose characteristics have been recorded on Table 7. 
EXAMPLE NO. 24 
Into a 50 lt autoclave provided with a heating sleeve and a stirrer, there 
were loaded 1.4 kg of a polyethylene prepared with unsupported 
Ziegler-catalysts and which showed the following characteristics: 
melt index=18 
density=0.9630 
CH.sub.3 /100 C number=0.26 
melt temperature (DSC)=133.degree. C., 
together with 0.6 kg of a ground calcium carbonate, with 90% of the 
particles sized below 10.mu., 40 g of a surfactant consisting of 
alkylphenol ethoxylate with 4 moles of ethylene oxide, and 14 lt of 
technical hexane. 
The mixture was then heated in the autoclave by sending steam through the 
sleeve until attaining the following conditions: 
temperature=150.degree. C. 
pressure=5.4 kg/sq.cm 
The mixture, containing the polyethylene in solution, was ejected through a 
nozzle of the 2 mm diameter into the external atmospheric ambient and hit 
at a distance of about 5 mm from the nozzle by the flow of saturated steam 
ejected from a nozzle of 4 mm diameter, arranged at an angle with the 
first nozzle of about 90.degree.. The operational conditions were: 
flow rate of solution=15 kg/hr 
impact speed of steam=420 m/sec. 
The product thus obtained consisted for 70% of fibers from 1 to 3 mm long 
and with a diameter of from 1 to 15.mu., and for 30% of flat fibers from 1 
to 3 mm long, from 50 to 100.mu. wide and from 1 to 15.mu. thick, while it 
contained less than 0.3% by weight of solvent. 
The density of the product (at 23.degree. C.) amounted to 1.162 g/cu.cm. 
A mixture consisting of 150 g of the fibers thus obtained and of 350 g of 
cellulose (60% Husum Birch, 20% Husum Kraft and 20% Modo Crown) was 
kneaded with 25 lt of water. Thereby was obtained instantaneous dispersion 
in the water of the fibrous mixture. With the thus obtained paste, and 
operating according to the procedures described in example 1, sheets were 
prepared whose characteristics have been recorded on Table 7. 
EXAMPLE NO. 25 
In this example is illustrated the preparation of fibers starting from a 
polyethylene solution free of surfactants and a comparison is made between 
the dispersability in water of the fibers thus obtained and that of the 
fibers prepared in the presence of a surfactant, according to the 
preceding examples. 
In the same autoclave of example 24 were loaded 2 kg of the polyethylene 
described in said example, 0.260 kg of talc and 20 lt of technical hexane. 
Through heating the following conditions were established in the autoclave: 
temperature=152.degree. C. 
pressure=5.2 kg/sq.cm 
The mixture containing the polyethylene in solution was ejected into the 
outer atmospheric ambient through a nozzle of a diameter of 2 mm, and was 
hit at a distance of 1.5 mm therefrom with a jet of carbon dioxide ejected 
by a nozzle of 4 mm diameter, forming an angle of 90.degree. with the 
ejected solution. The other operational conditions were: 
flow rate of the solution=15 kg/hr 
impact speed of the CO.sub.2 =450 mt/sec. 
The product thus obtained consisted for 70% of fibers from 1 to 2 mm long 
and of a diameter comprised between 1 and 20.mu., and for 30% of flat 
fibers from 1 to 2 mm long, from 50 to 100.mu. wide and from 1 to 20.mu. 
thick. The density of the product (at 23.degree. C.) amounted to 1.050 
g/cu.cm. 
150 g of the fibers thus obtained and 350 g of cellulose (60% Husum Birch, 
20% Husum Kraft and 20% Modo Crown) were mixed together in 25 lt of water. 
In order to obtain a good dispersion are required about 5 minutes. The 
paste was then processed according to the procedures described in example 
1 and the properties and characteristics of the paper were recorded on 
Table 7. 
EXAMPLE NO. 26 
Into the same autoclave of example 17 were loaded 7 kg of a polyethylene 
having the same characteristics of that of example 17, together with 20 g 
of a surfactant consisting of an ethoxylated stearylamine, 80 lt of 
technical hexane and 3 kg of the calcined clay described in example 21. By 
heating, the following conditions were established in the autoclave: 
temperature=169.degree. C. 
total pressure=10.9 kg/sq.cm 
nitrogen overpressure=2.8 kg/sq.cm 
Through a pipe sheathed with a steam heated sleeve, the mixture, containing 
the dissolved polyethylene, was conveyed to the nozzle and ejected into 
the outer atmospheric ambient, where it was hit at a distance of 2 mm from 
the nozzle and at a right angle by a saturated steam jet. The operational 
conditions were the following: 
temperature of the solution at the nozzle=180.degree. C. 
diameter of the solution ejecting nozzle=2 mm 
flow rate of the solution=150 kg/hr 
pressure of the solution at the nozzle=11.5 kg/sq.cm 
diameter of steam ejecting nozzle=4 mm 
impact speed of the steam=450 mt/sec. 
The product thus obtained appeared to consist for 70% of fibers from 1 to 3 
mm long and with a diameter of between 1 and 15.mu., and for 30% of flat 
fibers having a length of from 1 to 3 mm, a width of from 20 to 50.mu. and 
a thickness of between 1 and 15.mu.. The density (at 23.degree. C.) of the 
product amounted to 1.166 g/cu.cm. 
A mixture of 150 g of the fibers thus obtained and 350 g of cellulose (60% 
Husum Birch, 20% Husum Kraft and 20% Modo Crown) was kneaded with 25 lt of 
water, thereby obtaining an immediate homogeneous dispersion. Using this 
paste and operating according to the procedures described in example 1, 
sheets were prepared whose properties and characteristics have been 
recorded on Table 7. 
The following examples illustrate one of the preferred embodiments of the 
present invention, consisting in using the hitting fluid in form of a mass 
geometrically co-axial with the ejecting solution nozzle. 
EXAMPLE NO. 27 
Into a stainless steel 20 lt autoclave, fitted with a heating sleeve and 
provided with a blade stirrer, 800 g of polyethylene, obtained with 
Ziegler-type catalysts, non-modified monostadium, and having the following 
characteristics: 
melt index=1.6 
density=0.9525 
CH.sub.3 /100 C number&lt;0.1 
melt temperature (DSC)=133.degree. C., 
were introduced besides 6 g of a surfactant consisting of ethoxylated 
stearylamine and 10 lt of technical hexane. 
Using an oil heating, in the autoclave were established the following 
conditions: 
temperature=185.degree. C. 
total pressure=13.0 kg/sq.cm 
nitrogen overpressure=3.5 kg/sq.cm 
There was thus obtained a solution of polyethylene in hexane. For the 
preparation of the fibers starting from said solution, there was used a 
system of circular co-axial nozzles of the type illustrated by FIG. 3, 
having the following characteristics: 
diameter of the solution ejecting nozzle (3)=2 mm 
diameter of the hitting fluid ejecting nozzle (4)=4 mm 
length of chamber (5)=10.4 mm 
maximum diameter of chamber (5)=7.5 mm 
value of angle .alpha.=80.degree. 
With reference to FIG. 3, through a thermically insulated duct the 
polyethylene solution was fed into duct (1), while saturated steam was fed 
into duct (2). The operational conditions were as follows: 
flow rate of the solution=105 kg/hr 
impact speed of steam=210 mt/sec. 
The product that was gathered consisted for 90% of fibers from 4 to 5 mm 
long and having a diameter comprised between 1 and 5.mu., and for 10% of 
flat fibers from 4 to 5 mm long, from 15 to 20.mu. wide and from 1 to 
5.mu. thick. The superficial area of the product amounted to about 4 
sq.mt/g. 
EXAMPLE NO. 28 
Into the same autoclave of example 27 were introduced 900 g of the 
polyethylene described in example 27, and 10 lt of technical hexane. Using 
an oil heating, in the autoclave were established the following 
conditions: 
temperature=170.degree. C. 
total pressure=11.9 kg/sq.cm 
nitrogen overpressure=3.5 kg/sq.cm 
For the preparation of the fibers was used a nozzle device of the type and 
of the dimensions of that described in example 27, but characterized by an 
angular value .alpha.=50.degree.. 
Using a duct sheathed by a sleeve and heated by vapor, duct (1) was fed 
with the polyethylene solution, while into duct (2) was fed a nitrogen 
flow. The operational conditions at the nozzle were: 
temperature of the solution=190.degree. C. 
flow rate of the solution=95 kg/hr 
impact speed of the nitrogen=320 mt/sec. 
A product was thereby obtained which consisted almost exclusively of fibers 
from 4 to 5 mm long and from 1 to 3.mu. thick. The superficial area of the 
product amounted to 3.5 sq.mt/g. 
EXAMPLE NO. 29 
Into the same autoclave of example 27 were introduced 720 g of 
polypropylene with a high index of syndiotacticity, obtained with 
Ziegler-type catalysts and having the following characteristics: 
melt index=6.5 
density=0.9083 
melt temperature (DSC)=160.degree. C. 
besides 6 g of a surfactant obtained from the condensation of 1 mole of 
stearic acid with 5.5 moles of ethylene oxide, and 10 lt of technical 
hexane. 
By means of heating, in the autoclave were established the following 
conditions: 
temperature=171.degree. C. 
total pressure=8.8 kg/sq.cm 
nitrogen overpressure=3.0 kg/sq.cm 
For the preparation of the fibers was used a circular nozzle system of the 
type and dimensions illustrated in example 27, but characterized in that 
the angle .alpha. was equal to 45.degree.. 
Through a sleeved and vapor-heated pipe, duct (1) was fed with the 
polypropylene solution while into duct (2) was fed an oxygen flow. 
The operational conditions at the nozzles were: 
temperature of the solution=190.degree. C. 
flow rate of the solution=90 kg/hr 
impact speed of the oxygen flow=420 m/sec. 
Thereby was obtained a product consisting totally of fibers from 4 to 5 mm 
long, with a diameter of from 1 to 3.mu., and with a superficial area of 4 
sq.mt/g. 
TABLE 1* 
__________________________________________________________________________ 
Degree of 
Weight 
Thickness 
Breaking load 
Elongation at 
Length of 
Bursting 
Tearing 
besting S.R. 
g/sq. mt 
.mu. in Kg. break in % 
break, mt. 
Kg/sq. cm 
in g Porosity 
__________________________________________________________________________ 
RAUMA-type 
22 61 130 44 2.5 4.800 1.5 54 1550 
cellulose** 
27 64 130 43 2.5 4.500 1.7 55 920 
35.5 62 120 4.7 2.5 5.000 2.0 53 450 
41 62 120 5.5 2.0 5.900 2.1 50 320 
Example no 1 
21.5 62 150-200 
1.9 2.0 2.000 0.5 57 2050 
27 61 140-200 
2.5 2.0 2.750 0.8 60 850 
34 59 100-180 
2.3 2.0 2.600 0.9 60 450 
42 57 140 2.5 2.5 3.000 0.8 50 300 
Example no 2 
22.5 64 120-150 
2.6 2.0 2.700 0.9 70 1100 
34 63 120-140 
2.6 1.5 2.750 1.0 70 650 
42 67 120-150 
3.5 1.5 2.500 1.2 70 250 
52 67 120-130 
3.5 1.5 2.500 1.2 64 100 
Example no 4 
25.5 61 130 2.1 2.0 2.300 0.7 38 1000 
34 58 120 2.5 2.0 2.900 0.8 37 1150 
45 59 120 3.0 2.0 2.450 0.9 33 500 
__________________________________________________________________________ 
*The characteristics have been determined according to the ATICELCA rules 
(Associazione Tecnici Italiani Cellulose e Carta). 
**Sulphite conifer cellulose 
TABLE 2* 
__________________________________________________________________________ 
70% RAUMA 70% MODO, 
RAUMA-TYPE 30% OF POLY- MODO-TYPE 30% OF POLY- 
CELLULOSE ETHYLENE FIBRES 
FIBRES** ETHYLENE 
__________________________________________________________________________ 
FIBRES 
Degree of beating 
28 
39 44 
54 25 
36 
44 57 
24 
34 
44 56 
25 
55 45 
50 
S.R. at 22.degree. C. 
Weight, g/sq. mt 
66.6 
65.7 
65.8 
66.4 
62.20 
63.92 
61.20 
66.40 
64.4 
62.2 
64.5 
63.8 
63.96 
60.92 
61.18 
61.64 
Breaking load, 
2.5 
3.2 2.8 
3.6 1.52 
1.90 
1.63 
1.98 
3.0 
3.8 
4.3 4.7 
1.97 
1.66 
2.06 
2.56 
Kg 
Elongation at break 
2.4 
2.4 2.3 
2.9 2.3 
2.6 
2.4 2.6 
1.9 
2.6 
3.2 3.2 
2.6 
1.8 2.0 
2.9 
Length of breaking 
2500 
3250 
2850 
3600 
1659 
2000 
1800 
2000 
3100 
4000 
4450 
4900 
2050 
1800 
2250 
2750 
mt. 
Tearing resistance, 
112 
92 104 
96 72 
80 
72 64 
104 
84 
84 64 
84 
74 72 
72 
g 
__________________________________________________________________________ 
70% BIRCH, 70% KRAFT, 
30% POLY- KRAFT-TYPE 30% POLY- 
BIRCH CELLULOSE*** 
ETHYLENE FIBRES 
CELLULOSE**** 
ETHYLENE 
__________________________________________________________________________ 
FIBRES 
Degree of beating 
25 
33 43 
58 22 
29 
36 47 
25 
35 
45 58 
28 
41 45 
57 
S.R. at 22.degree. C. 
Weight, g/sq. mt 
72.4 
65.0 
67.0 
65.0 
65.76 
63.80 
66.80 
60.60 
67.2 
67.0 
65.7 
64.0 
64.20 
65.80 
67.40 
66.08 
Breaking load, 
2.5 
3.5 4.9 
4.8 1.63 
2.04 
2.17 
2.23 
5.3 
7.0 
6.5 7.8 
2.61 
2.86 
3.18 
3.16 
Kg 
Elongation at break 
2.2 
2.5 3.2 
3.4 2.3 
2.4 
2.9 2.7 
3.1 
3.7 
3.2 3.8 
3.4 
3.2 3.3 
3.0 
Length of breaking 
2500 
3550 
4850 
4900 
1650 
2150 
2150 
2500 
5300 
6950 
6650 
7550 
2700 
2900 
3150 
3200 
mt 
Tearing resistance, 
60 
80 80 
60 52 
68 
60 56 
124 
108 
152 
104 
108 
100 
116 
120 
g 
__________________________________________________________________________ 
*The characteristics have been determined according to ATICELCA rules 
**Cellulose manufactured by the Mooch Domejos Co. 
***Birchtree cellulose 
****Bleached sulphate cellulose 
TABLE 3* 
__________________________________________________________________________ 
Reference cellulose 
(60% Birch, 20% Modo 
and 20% Kraft) Example no 6 Example no 7 
__________________________________________________________________________ 
Degree of beating 
26 38.5 
47.5 
56 20.5 
26.5 
38 53 25 39 47.5 
S.R. at 22.degree. C. 
Weight, g/sq. mt 
61 62 80 61 63 62 60 61 60 60 60 
Breaking load kg. 
6.7 8 8 8 3.7 3.5 3.8 4.3 3.5 4 4.2 
Elongation at 
2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 
break, % 
Length of break mt 
7320 
8600 
8830 
8750 
2850 
3760 
4220 
4700 
3825 
4370 
4590 
Resistance to 
41 44 40 38 40 39 39 38 40 41 40 
tearing, g 
__________________________________________________________________________ 
*The characteristics have been determined according to ATICELCA rules 
TABLE 4* 
__________________________________________________________________________ 
Reference Cellulose (RAUMA) 
Example 9 Example 10 
__________________________________________________________________________ 
Degree of beating S.R. 
25.5 
33 41.5 
52 21.5 
30 40.5 
50 24 29 38 46.5 
at 22.degree. C. 
Weight, g/sq. mt 
62 67 66 67 61 61 61 61 60 59 61 62 
Breaking load, kg 
3.8 4.5 4.4 5.0 2.1 2.3 2.6 
2.8 1.9 2.4 2.7 2.8 
Elongation at break, % 
2.5 2.5 2 2.5 2.5 2 2 2.5 2 2.5 2.5 2 
Length of break, mt 
4000 
4480 4450 
4975 
2500 
2500 2800 
3050 
2100 
2700 2950 
3000 
Tearing resistance, g 
62 58 52 55 40 40 40 38 40 40 40 35 
__________________________________________________________________________ 
Example 11 Example 12 
__________________________________________________________________________ 
Degree of beating S.R. 
22 26.5 
37.5 
44 18 26 31.5 
40.5 
at 22.degree. C. 
Weight, g/sq. mt 
61 62 61 58 62 62 60 57 
Breaking load, kg 
2 2.3 
2.7 2.8 1.5 1.9 2.1 
2.6 
Elongation at break, % 
2 2 2 2 2 2 2 2 
Length of break, mt 
2180 
2470 
2550 
3200 
1600 
2050 
2300 
3050 
Tearing resistance, g 
40 40 37 34 40 41 40 32 
__________________________________________________________________________ 
*the characteristics have been determined according to ATICELCA RULES 
TABLE 5* 
__________________________________________________________________________ 
Reference cellulose 
(60% Birch, 20% Modo, 
Example 
Example 
Example 
20% Kraft) 13 14 15 
__________________________________________________________________________ 
Degree of refining 
26 38.5 
47.5 
56 37.6 37.7 37.2 
S.R. at 22.degree. C. 
Weight, 61 62 60 61 60 52 60 
g/sq. mt 
Breaking load, 
6.7 8 8 8 4.1 4.1 4.7 
Kg 
Elongation at 
2.5 2.5 2.5 2.5 2.9 2.8 2.8 
break in % 
Length of break, 
7320 
8600 
8830 
8750 
4670 5400 5410 
mt 
Tearing resistance, 
41 44 40 38 38 20 50 
__________________________________________________________________________ 
*The characteristics have been determined according to ATICELCA rules. 
TABLE 6 
______________________________________ 
TEST A B C 
______________________________________ 
Weight g/mg 70.4 68.1 69.5 
Longitudinal breaking 
6.6 3.51 4.8 
load, in kg 
Transversal breaking 
2.04 1.35 1.8 
load, in kg 
Length of longitudinal 
6300 3440 4250 
break, mt. 
Length of transversal 
1930 1350 1800 
break, mt. 
Average length of break 
4110 2400 3020 
in mt. 
Elongation at longitudinal 
3.1 3.0 3.0 
break, in % 
Elongation at transversal 
5.3 3.8 3.9 
break, in % 
______________________________________ 
TABLE 7* 
__________________________________________________________________________ 
Example no 
17 18 19 20 21 22 23 24 25 26 
__________________________________________________________________________ 
Degree of beating 
41 
45.5 
40 
37.5 
35 
43 
33 
38 
38.5 
38 
S.R. at 22.degree. C. 
Weight g/sq. mt 
63.8 
64 
65.5 
66.6 
62.5 
64.3 
65.9 
62.4 
64.4 
63.8 
Breaking load, kg 
5.35 
5.09 
5.61 
4.20 
4.72 
4.62 
5.33 
4.08 
5.56 
4.70 
Elongation at break % 
2.3 
2.05 
2.4 
1.9 
2.3 
2.0 
2.9 
2.2 
2.3 
2.0 
Length of rupture, mt 
5258 
4962 
5431 
4026 
4980 
4485 
4871 
4087 
5180 
4595 
__________________________________________________________________________ 
*The characteristics have been determined according to ATICELCA RULES