CA1082861A - Aggregate of fibrous material used for synthetic pulp and process for preparing same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An aggregate of a fibrous material used for a synthetic pulp is provided which essentially consists of a surface active agent for an emulsifier, a hydrophilic high molecular weight compound, a hydrophobic finely divided inorganic substance particle and an olefin polymer, said hydrophobic finely divided inorganic substance particle being effectively integrated with the polymer body of the fibrous material. Said aggregate is prepared by flushing, at at least 100°C, an emulsion composed of the above-mentioned four ingredients and water and a solvent into an environment of a low pressure.

Description

1~2861 This invention relates to an aggregate of a fibrous material which is suitable for a so-called synthetic pulp, and further to a process for prepariny said aggregate.
The aggregate of a fibrous material exhibits hydrophilic and self-bonding properties and is characterized particularly as having finely divided inorganic substance particles effectually integrated therewith.
Heretofore, many procedures have been proposed to produce from polyolefin an aggregate of a fibrous material which is used for a so-called synthetic pulp. A typical procedure involves emulsion-flush spinning wherein an aqueous emulsion of polyolefin solution is flushed at elevated temperature and pressure through an orifice into the atmosphere as disclosed in, for example, Japanese published patent application 32,133/1972 and Japanese laidopen patent application 31,916/1974. The aggregate of a fibrous material so obtained is subjected to beating or refining to form a pulp-like product. The pulp-like product, which is comprised of a particle of an aggregate of fibrils, is of a large specific surface area and exhibits good dispersibility in water and self-bonding property.
Therefore, the pulp-like product is used alone or in combination with wood pulp for manufacturing paper of a large strength.
In order to improve the performances of paper, reduce the material cost and economize petroleum resources, it has been desired and proposed to employ a large amount of a finely divided inorganic substance together with the polyolefin raw material in the emulsion flush spinning procedure. However, conventional finely divided particles

- 2 -1~8~8~;1 can hardly be integrated with pulp-like product by the cmulsion flush spinning. The use of conventional inorganic particles in the emulsion flush spinning was disclosed in Japanese published patent application 10,484/1973. In this case, however, inorganic par'cicles are not effectively integrated with pulp-like product. That is, most conven-tional finely divided inorganic substances are intrinsically hydrophilic or have hydrophilic groups such as a hydroxyl group on the surface. Therefore, when an aqueous emulsion of polyolefin solution is prepared, the finely divided inorganic substances are liable to be present in the aqueous phase rather than the solvent having polyolefin dissolved therein. When the aqueous emulsion of polyolein is flushed into the atmosphere, most of the finely divided inorganic substances are dislodged together with a pre-dominant amount of water from an aggregate of fibrous materials formed by the flushing, and some are kept together with a minor amount of water in the aggregare of fibrous materials. The part of the finely divided inorganic substances kept together with water in the aggregate of fibrous materials, when said aggregate is disintegrated in water, is dislodged from said aggregate into the water.
To sum up, most conventional finely divided inorganic substances are liable to be dislodged from the polyolefin body in the course of manufacturing paper. Such dislodg-ing of finely divided inorganic substances not only is an economical loss, but also makes turbid the waste water from the paper-manufacturing process and reduces the quality of paper.
Another procedure of producing fibrous material has 1()82861 also been proposed wherein a solution of polyolein in a solvent is flushed at elevated temperature and pressure through an orifice into the atmosphere. A finely divided inorganic substance may be incorporated in the polyolefin solution as disclosed in Japanese laid-open patent appli-cation 55,264/1973. Since this procedure involves no use of water, the finely divided inorganic substance is capable of being kept in the aggregate of a fibrous material formed by flushing. However, when said aggregate ls disintegrated in water, a moderate amount of the finely divided inorganic substance is inevitably dislodged from the fibrous material into the water, because the finely divided inorganic substance has more affinity to water than to polyolefin. Further, a pulp prepared from such fibrous material is only a little or not at all hydrophilic and is poor in self-bonding property. Even when this pulp is combined with wood pulp, the resulting paper is poor in mechanical strength, such as tensile strength, particularly in surface strength. This paper is not advantageously employed for printing purposes.
It is an object of the present invention to provide an aggregate of a fibrous material used for synthetic pulp, which aggregate is hydrophilic and possesses improved self-bonding property and in which a finely divided inorganic substance is effectively integrated with the polymer body of the fibrous material.
Other objects and advantages of the present invention will be apparent from the following description.
In accordance with the present invention, there is provided an aggregate of a fibrous material essentially 108~8~1 consisting of a surface active agent, a hydrophilic high molecular weight compound, a hydrophobic finely divided inorganic substance particle and an olefin polymer, said hydrophobic finely divided inorganic substance particle being effectively integrated with the polymer body of the fibrous matexial.
By the phrase "the finely divided inorganic substance particle is effectively integrated with the polymer body of the fibrous material" is meant that the finely divided inorganic substance particle is integrated with the polymer body of the fibrous material to an extent such that, when the aggregate of the fibrous material is disintegrated in water in a normal manner for the preparation of pulp, a substantial part of the finely divided inorganic substance particle is capable of being still kept inside the polymer body of each multi-fibril or between possible interlaced multi-fibrils.
The aggregate of a fibrous material of the invention is prepared by a process wherein an aqueous emulsion consisting essentially of a surface active agent for an emulsifier, a hydrophilic high molecular weight compound, an olefin polymer, a hydrophobic finely divided inorganic substance particle, water and a solvent for the olefin polymer, maintained at a temperature of at least 100C is flushed through an orifice of a nozzle into an atmosphere of a lower pressure.
The olefin polymer used for the preparation of the aggregate of a fibrous material of the invention includes homopolymers and copolymers of olefin monomers such as ethylene, propylene, butene-l and 4-methylpentene-1. It `. ~ ' further includes copolymers of an olefin monomer and a po:Lar vinyl or vinylidene monomer radically copolymerizable with the olefin monomer. The olefin polymer may be used in combination with a minor amount, i.e., less than 40~ by weight, of another hydrophobic polymer based on the total weight of the olefin polymer and the hydrophobic polymer.
Such hydrophobic polymer includes, for example, polystyrene, polymethyl methacrylate and polyvinyl chloride.
The hydrophilic high molecular weight compound includes, for example, polyv nyl alcohol, polyacrylic amide, polyethylene oxide, carboxymethylcellulose, sodium polyacrylate and soluble starch.
The surface active agent is used for the purpose of forming and stabilizing an aqueous emulsion comprisedof (1) a non-aqueous phase having the olefin polymer dissolved and the finely divided inorganic substance dispersed in a solvent for the olefin polymer and (2) an aqueous phase having the hydrophilic high molecular weight compound dissolved in water. The surface active agent preferably used is water-soluble and is of a high molecular weight but distinguished from the above-mentioned hydrophilic high molecular weight compound in that the latter has no function of forming and stabilizing the above-mentioned aqueous emulsion and is used solely for imparting to the resulting pulp-like product an improved affinity for water. The above-mentioned hydrophilic high molecular weight compound imparts to the pulp-like product an affinity for water and wood pulp. However, if the surEace active agent is not used, i.e., if a so-called emulsion-flushing is not effected, the resulting pulp-like product is not sat:isfactory in that it is composed of coarse and large-size particles and contains a minor amount of the hydrophilic high molecular weight compound taken therein.
The sur~ace active agent used may be anionic, cationic, nonionic or ampholytic. A preferable surface active agent is of a high molecular weight and selected from copolymers of the following four types.
The first type copolymer is comprised of units derived from at least one monomer-of the formula:

CH = CH
C=O C=O
OA OB

and units derived from at least one monomer of the formula:

CH2= jC' i.e. the copolymer comprises a structural unit of the formula:

~ CH - CH - CH2 - C ~ or ~ CH - CH - CH2 - C

~ C=O C=O R2 C=O C=O R2 OA OB OB OA

where A represents a metal selected from the group consisting of Li, Na, 1/2Ca, 1/2Mg, 1/2Zn and l/3AL; B represents a member selected from the group consisting of hydrogen, a hydrocarbon radical having 1 to 20 carbon atoms, Li, Na, 1/'2Ca, 1/2Mg, 1/2Zn and 1/3A0; Rl represents a member se~lected from the group consisting of hydrogen and a hydrocarbon radical having from 1 to 30 carbon atoms; and R2 represents a member selected from the group consisting of hydrogen, -COOR3 (where R3 is hydrogen or a hydrocarbon radical having 1 to 30 carbon atoms), -OCOR4 (where R4 is a hydrocarbon radical having 1 to 20 carbon atoms), halogen or -CH2OH.
The second type copolymer is comprised of units derived from at least one monomer of the formula:

CH2=fH or CH2=Cl-cH3.

C=O C=O
OA OA

and units derived from at least one monomer of the formula:

IR

CH2=C

(wherein A, Rl and R2 are as defined above).
The third type copolymer is comprised of units derived from ethylene and units expressed by the formula:

-CH -CH-wherein R5 represents a member selected from the group consistiny of -Oll and -CH2O~I.
The forth type copolymer is a vinyl monomer-grafted po:Lyvinyl alcohol.
The first type copolymer includes preferably a styrne-sodium maleate copolymer, a styrene-alkyl methacrylate--sodium maleate copolymer, an ethylene-sodium maleate copolymer and a hexene-sodium maleate copolymer. The second type copolymer includes preferably an ethylene-sodium acrylate copolymer, an olefin sodium methacrylate copolymer and an olefin sodium acrylate copolymer. The third type copolymer includes preferably a saponified ethylene-vinyl acetate copolymer and an ethylene-allyl alcohol copolymer.
The fourth type copolymer is a vinyl monomer-grafted polyvinyl alcohol. The vinyl monomer to be grafted onto polyvinyl alcohol includes, for example, styrene, vinyl acetate, alkyl esters of acrylic acid or methacrylic acid.
The grafted polyvinyl alcohol preferably posesses a molecular weight of 200 to 4,000, expressed in terms of average degree of polymerization. Feed vinyl monomer to polyvinyl alcohol in graft-polymerization is preferably about 5 to 2,000% by weight.
The amount of the surface active agent is preferably 0.05 to 10~ by weight based on the weight of the aggregate of a fibrous material.
The hydrophobic finely divided inorganic substance particles used for the preparation of the aggregate of a fibrous material of the invention means those which are water-repellent and, in general, when put in water, they rise to the surface without getting wet. Preferable 108'~8fà~

hyclrophobic finely divided inoryanic substance particles may be defined as meaning those which rise to the surface without getting wet when they are put into water containing, fox example, three g/liter of the surface active agent used for the preparation of the aggregate of a fibrous material of the invention. The hydrophobic finely divided inorganic substance particles exhibit good affinity for organic solvents and are capable of being easily dispersed therein. They possess an average particle size of below five microns, preferably below two microns and more pre-ferably below one micron. They should not possess an average particle size larger than the particle size of the emulsion formed in the preparation of the fibrous material aggregate of the invention.
The hydrophobic finely divided inorganic substance particles are prepared by chemically or physically treating conventional finely divided inorganic substance particles.
Such hydrophobic treatment includes, for example, esterifi-cation with alcohol of hydroxy groups present on the surface of a finely divided metal oxide such as TiO2 and SiO2 or alkylsilyl etherification of such hydroxy groups with silane such as alkylchlorosilane, alkylhydroxysilane or alkylalcoxysilane. It further includes the surface treatment of finely divided calcium carbonate with a fatty acid, a resin acid or an amine. It still further includes bringing finely divided kaolin or talc into contact with vapor of Me2Si(OMe)2 at an elevated temperature.
The hydrophobic finely divided inorganic substance particle is advantageous over conventional finely divided inorganic substance particle in the following points.

First, the former particle has good affinity for an organic solvent but little or no affinity for water and, therefore, when said particle is incorporated in an emulsion comprised of a non-aqueous phase having the olefin polymer dissolved in a solvent, and an aqueous phase having the hydrophilic high molecular weight compound dissolved in water, said particle is present in the non-aqueous phase. Consequently, when the emulsion is flushed into a low pressure environment, said particle is effectively integrated with the polymer body of the fibrous material. Second, said particle exhibits enhanced affinity for the olefin polymer and the adhesion of said particle to the polymer body of the fibrous material is strong to an such extent that, when the aggregate of the fibrous material is subjected to a shearing force caused by beating the aggregate in water, only a negligible amount of said particle is dislodged from the aggregate.
The hydrophobic finely divided inorganic substance particle may be present in the aggregate of a fibrous material in an amount of not more than 20 times the weight of the olefin polymer. The lower limit of the amount of the inorganic substance particle is not critical, but should preferably be such that at-least an appreciable reduction in manufacturing cost of the pulp-like product and an appreciable improvement in the properties of the pulp-like product are obtainable. The use of the inorganic substance particle in excess of the above-mentioned upper limit leads to undesirably increased reduction in strength of the fibrous material and in form stability of the fibrous material. A preferable amount of the inorganic substance particle is within the range of from 1/10 to 10/1 of the weiyht of the olefin polymer.
The aqueous emulsion is prepared by combining a surface acti~e agent, a hydrophilic high molecular weight compound, an olefin polymer, a hydrophobic finely divided inorganic substance particle, water and a solvent for the olefin polymer.
The solvent used includes, for example, a hydrocarbon such as pentane, hexane, petroleum ether, cyclopentane, cyclohexane, benzene and toluene; and a halogenated hydro-carbon such as methylene chloride and trichloroethylene.
The solvent may be used alone or in combination.
The ratio of water to the solvent is preferably selected within the range from 0.1 to 6 by volume. When the ratio of water to the solvent is less than 0.1 by volume, the flushed product is substantially in the form of continous strands. These continuous strands are not sufficiently fibrillated upon beating or refining. In contrast, the use of a ratio of water to solvent in excess of 6 is disadvantageous from the standpoint of the manu-facturing cost. More preferably the ratio of water to the solvent is selected so that an oil-in-water type emulsion may be formed in order to make the hereinbefore mentioned surface active agent more effective.
The manner whereby the hydrophobic finely divided inorganic substance particle is incorporated in the aqueous emulsion is not critical. It is preferable, however, to previously disperse said particle in the solvent in order to prevent said particle from agglomerating in the aqueous emulsion and to make the aqueous emulsion more uniform.

108286~

If the inorganic substance particle agglomerates in the aqueous emulsion, said particle is liable to be dislodged from the a~gregate of a fibrous material when the aggregate is beaten or refined. It is most preferable to previously disperse said particle in the solvent by using a dispersant, such as an oil-soluble surface active agent, and strongly stirring the mixture.
The solid content, i.e. the total content of the olefin polymer and the hydrophobic finely divided inorganic substance particle in the non-aqueous phase is preferably 5 to 40% by weight based on the weight of the non-aqueous phase. The content of the hydrophilic high molecular weight compound in the aqueous phase is preferably 0.1 to 50% by weight, more preferably 0.2 to 20% by weight, based on the total weight of the olefin polymer and the hydrophobic finely divided inorganic substance particle. The amount of the surface active agent is selected so that the surface active agent in the resulting fibrous material may be, as hereinbefore mentioned, preferably 0.05 to 10~ by weight based on the weight of the resulting aggregate of a fibrous material.
Suitable amounts of additives such as a viscosity--reducing agent, an antioxidant, a weathering stabilizer - and an antistatic agent may be lncorporated in the emulsion.
The emulsion is maintained at a temperature of at least 100C. This is for the purpose of dissolving the olefin polymer in the solvent and, when the emulsion is flushed, evaporating the solvent as quickly and completely as possible from the flushed product.
The prepared emulsion is extruded by the autogenous pressure of the solvent and water or by pressurizing the emulsion, for example, by the introduction of an inert gas such as nitrogen and carbon dioxide, through an orifice of a nozzle into an environment of a lower pressure. By the term "environment of a lower pressure" is meant an environment of a pressure lower than that of the emulsion prior to the extrusion. The pressure of the environment is conveniently atmospheric. The nozzle used may be conventional, but should preferably be of a shape suitable for providing a fibrous material aggregate of the desired shape.
When the emulsion is extruded through an orifice, the polymer components are oriented and distorted by a shearing force in the orifice and, the instant the emulsion emerges from the orifice in a low pressure environment, they solidify due to the abrupt evaporation of the solvent and water and the cooling caused by the evaporation, while the polymer components are interlaced with and restricted by each other. Thus, an aggregate composed of somewhat interlaced fibrous materials of a relatively short length is formed. As hereinbefore mentioned, when the polymer components solidify, the hydrophobic finely divided inorganic substance particle present in the non-aqueous phase of the emulsion is kept substantially inside the olefin polymer of the fibrous material and a substantial part of the hydrophilic high molecular weight compound present in the aqueous phase of the emulsion is also kept in or integrated with the olefin polymer. Consequently, the hydrophobic finely divided inorganic substance is effectively integrated with the polymer body of the fibrous material as hereinbefore mentioned.

The aggregate of a fibrous material is capable of being easily beaten or refined into pulp-like particles composed of interlaced fibrils, said particles haviny a desired size, for example, a size such that at least 95%
of the particles are capable of passin~ through a wire sieve of 24 mesh size as tested according to Japanese Industrial Standard P8207. It is also possible to prepare a pulp-like particle of a relatively large size by beating or refining the aggregate of a fibrous material to a lesser extent.
The internal structure of the pulp-like product prepared from the aggregate of a fibrous material can be examined conveniently as follows. A specimen of the pulp-like product is embedded in a polymer resin, and the polymer resin is sliced into very thin pieces. The pieces are dyed with a dye capable of dying only the hydrophilic high molecular weight compound, and then, observed by an electron microscope. Thus, it is clear that the hydrophobic finely divided inorganic substance particle is effectively integrated with the polymer body of the fibrils and the hydrophilic high molecular weight compound is arranged in a linear form of a continuous length and or a short length in parallel to the fiber axis. Such a specific internal structure cannot be obtained by a solution flush spinning procedure wherein a polymer is flushed not in the form of an emulsion but as a solution, as disclosed in Japanese laid-open patent application 55264/1973.
In a known process for manufacturing paper from pulp containing conventional finely divided inorganic substance particles, a large amount of the inorganic substance particles is dislodged from the pulp into water in the step of beating and the aqueous dispersion becomes opaque. In contrast, the aqueous dispersion of the pulp--like product of the invention, i.e. containiny hydrophobic finely divided inorganic substance particles, is of li-ttle or no opacity.
The pulp-like product prepared from the aggregate of a fibrous material of the invention is advantageous in the following points over known synthetic pulp prepared from polyolefin. First, the pulp-like product sediments in water in a manner similar to wood pulp and, therefore, it is easy to prepare a uniform aqueous dispersion from the pulp-like product or from its mixture with wood pulp.
Second, the material cost of the pulp-like product is low when the hydrophobic finely divided inorganic substance particle costs less than the olefin polymer, and it con-tributes to the economization of petroleum resources.
Third, the pulp-like product exhibits an improved heat distortion temperature and, consequently, when a wet sheet formed therefrom is heated in a dryer part of a paper--manufacturing process, the opacity of the sheet is not reduced. Fourth, in the case where the pulp-like product has~a predominant amount of the finely divided inorganic substance particle incorporated therein, the paper manu-factured therefrom or from its mixture with wood pulp is,when sub~ected to high temperature or high velocity treatment, not readily molten and undesirable plastic needle-like materials are not formed.
The invention will be illustrated by the following examples, in which percentage and part are by weight un;Less otherwise specified.
Example 1 A five liter volume stainless steel autoclave was charged with l.0 liter of hexane, 1.5 liters of water, 40 g of a finely divided polyethylene powder (trade name "Hi-zex 2100 Lp", supplied by Mitsui Petrochemical Co.), 40 g of a finely divided inorganic substance particle (shown in Table I below), 4 g of polyvinyl alcohol (trade name "Gosenol NM 14", supplied by Nihon Gosei Kagaku Co.) and 2 g of a sodium salt of styrene/maleic anhydride/methyl methacrylate copolymer (surface active agent). The content was heated to 140C and maintained at that temperature for 20 minutes, while being stirred, thereby to be emulsified.
The emulsion was flushed through a nozzle having an orifice of 1 mm length and 1.6 mm diameter, provided at the bottom of the autoclave, into an atmospheric pressure environment.
Twenty five g of (absolute dry weight) of the fibrous product so formed were beaten in 5 liters of water of using a single disk refiner of the Sprout-Waldron type (supplied by Kumagai Riki Kogyo Co.) until the fibrous product was fibrillated and cut into a size such that at least 95~ of the disintegrated product became capable of passing through a sieve of 24 mesh size as tested according to Japanese Industrial Standard P8207. The beaten product was placed on a wire cloth of 200 mesh and washed by pourlng water thereon for 20 minutes, and then dried.
An amount of the pulp-like product so obtained was placed in a crucible and baked at 800C for 2 hours in a muffle electrical furnace. The content of the finely divided inorganic substance particle in the pulp-like 108Z8~

product was calculated from the ash weight in the crucible.
The results are shown in Table I.

. Table I
Finely divided inorganic substance particles used and their contents in pulp-like products No. Inorganic substanceContent l Silicic acid A 3.8 2 " B 1.7

3 " C 1.6

4 " D 4.8 " E 5.2 6 Silica 3.1 7 Kaolin F 3.0 8 " G 0.8 9 Titanium oxide 2.5 Calcium sulfate 3.4 11 Alkyl-esterified silicic acid A 39.5 12 " 36.3 13 Hydrophobic silicic acid H45.4 14 Hydrophobic calcium OE bonate I 31.9 Hydrophobic kaolin J 45.2 16 " K 43.9 17 Hydrophobic talc 45.9 ..

108Z861 ~ ~

(Notes) (1) Inorganic substance specimens No.l through 10 are hydrophilic and capable of being uniformly dispersed in water but i,norganic substance specimens No.ll ., , ~lrouyh 17 are hyclrophobic, and incapabie of wetting and float on water.
(2) Particulars of the inorganic substances used are as - follows. -Specimen 1: trade name "TOKUSIL GUN" supplied by Tokuyama Soda Co.
Specimen 2: trade name ''~roKusIL U" supplied by Tokuyama Soda Co.
Specimen 3: trade name "AEROSIL 130"*supplied by Nihon Aerosil Co.
S~ecLmen 4: trade nan~e "Syloid 244"*supplied by-Fuji Devison Co.
Spec,umen 5: trade name "Syloid 65"*supplied by Fuji Devison Co. .' Specimen 7: trade name "A~SP 170" supplied by Engelhard Mineral &
Chemical Co.
Si-~cimen 8: trade name "UW 90" supplied by Engelhard Mineral & Chemical Co.
Specimen 11: silicic acid A treated with octanol under a reflux condition for 8 hours.
Specimen 12: silicic acid A treated with butanol at 230C for 4 hours.
SpecLmen 13: trade name "AEROSIL R972"*supplied by Nihon Aerosil Co.
Specim~n 14:. trade name "HAKUENKA CCR" supplied by Shiraishi Kogyo Co.
Spc-cimen 15: prepared by bringing kaolin (trade na~.e "ASP 100", supplied by Engelhard Mineral & Chemical Co.) in contact with gaseous Me2Si(QMe)2 at 200~C for two hours.
Specimen 17: prepared by bringing talc (average particle size, 5 microns) in contact with gaseous Me2Si(oMe)2 at 200C for two hours, * registered trade mark .
~r~

108'~861 Specimen 16: prepared by bringing kaolin (trade name "Satintone ~lo.5", Enqe ~ rd Mineral & Chemical Co.) in contact with gaseous Me2Si(aMe)2 at 200C for two hours.

As is apparent from Table I, hydrophilic inorganic substance particles fall away to a great extent from the pulp-like product in the course of manufacturing the pulp--like product, but hydrophobic inorganic substance particles are well retained in the pulp-like product.
Example 2 A five liter volume stainless steel autoclave was charged with 1.2 liters of hexane, 1.8 liters of water, 60 g of a finely divided polyethylene powder similar to that used in Example 1, 60 g of a hydrophobic finely divided silicic acid (trade name "Aerosil R972", supplied by Nihon Aerosil Co.), 6 g o~ polyvinyl alcohol similar to that used in Example 1 and 3 g of a sodium salt of styrene/-maleic anhydride/methyl methacrylate copolymer (surface active agent). The content was heated to 140C and main-tained at that témperature for 20 minutes, while beingstirred, thereby to be emulsified. After the emulsion was pressurized to a pressure of 20 atmospheres by nitrogen, the emulsion was flushed through a nozzle provided at the bottom of the autoclave into the atmosphere. The fibrous product so formed containing approximately 1,900%, based on the dry weight, of water was dehydrated by a home centrifugal thickener to the water content of 350%. The water separated was clear. The fibrous product contained 47.1%, based on the dry weight, of the inorganic substance, which content is approximately the same as the amount charged in the autoclave.
Twenty five g, based on the dry weight, of the fibrous product were disintegrated and then tested for inorc~anic su~stance content in a manner similar to that in Example 1. The final dry pulp-like product contained 45.5% of the inorganic substance. In the test process, the pulp-like pro~uct did not change in shape, i.e., did not collapse, upon baking.
Example 3 Sixty g of a finely divided polyethylene powder similar to that used in Example 1, 60 g of hydrophobic calcium carbonate similar to specimen No. 14 used in Example 1, 2 g of sorbitan monolaurate and 1.2 liter of hexane were well stirred in a home mixer. A five liter volume autoclave was charged with the above-mentioned mixture as well as 1.8 liter of water, 60 g of polyvinyl alcohol similar to that used in Example 1 and 3 g of a sodium salt of styrene/maleic anhydride/methyl methacrylate copolymer. Following the procedure set forth in Example 2, the content of the autoclave was emulsified, flushed into the atmosphere and dlsintegrated to obtain a pulp-like product. The fibrous product flushed from the autoclave contained 49.4%, based on the dry weight, of the calcium carbonate. The pulp-like product, after being washed, contained 43.9%, based on the dry weight, of the calcium carbonate.
Examples 4 through 7 Following the procedure set forth in Example 3, fibrous products were prepared from the compositions shown in Table II below and, then, pulp-like products were prepared therefrom. The content of finely divided inorganic substance particles is shown in Table III.

Table II
Polymer compositions used *l *2 *3 Surface Sorbitan E~ple PE PU~ CCR active*4 mDnO- hexane Water No. (g) (g) (g) agent(g) laurate(g) (~) (Q) 4 30 4 30 3 3 1.0 1.5 " 120 " " "
6 " " 180 " " " "
7 " " 270 " " " "

Notes:
*l Finely divided polyethylene powder similar to that used in Example 1.
*2 Polyvinyl alcohol similar to that used in Example 1.
*3 Hydrophobic calcium carbonate similar to specimen No. 14 used in Example 1.
*4 A sodium salt of styrene/maleic anhydride/methyl methacrylate copolymer.
' Table III
Inorganic substance content (~) Example No. in fibrous product in pulp-like product 4 48.9 41.0 77.2 73.6 6 84.6 81.3 7 88.8 86.3 .

Example 8 This example illustrates the manufacture of paper from the pulp-like products obtained in Examples 2 through 7.
The pulp-like products, i.e. beaten fibrous products, obtained in Examples 2 through 7 were capable of settling out in water and exhibited good dispersibility.
A wet sheet was formed from a mixture of 2 parts of each of the pulp-like products and 8 parts of wood pulp (a 2:8 by weight mixture of N.BKP and L.BKP, Canadian standard freeness of 450 ml~ by using a rectangular type sheet machine (supplied by Toyo Seiki Seisakujo) and according to Japanese Industrial Standard P8209. The wet sheet was dried at 110C for two minutes in a FC dryer (supplied by FC Seisakujo) and then calendered into paper.
The paper had the properties as shown in Table IV.

T~ble IV
Properties of Paper Basis Thick- Bulk Breaking Surface E~mple weig~t ness densi~y length strength Whiteness opacity No. (g/m ) (microns) (g/cm ) (km) (Wax No) (%) (~) 2 52.9 65 0.81 4.458A 86.5 75.7 3 49.9 70 0.71 3.987A 84.0 70.5 4 49.2 67 0.73 3.737A 85.8 73.1 48.3 67 0.72 4.177-8A 84.3 72.8 6 47.1 67 0.70 4.027-8A 84.2 72.2 7 49.2 68 0.72 4.027A 86.2 71.4 W~od 51.9 67 0.78 5.098-9A 81.5 62.8 pulp 108Z86~
Com~arative Example 1 A five liter volume autoclave was charged with 1.2 liters of hexane, 30 g of a finely divided polyethylene powder similar to that used in Example l and 30 g of a S rinely divided silicic acid particle (trade name "Aerosil 360"* supplied by Nihon Aerosil Co.). The content was heated to 14QC and maintained at that temperature, while being stirred, thereby to form a solution. The solution was flushed through a nozzle having an orifice of l mm length and 1.6 mm diameter into the atmosphere. The continuous strand-like fibrous product so obtained con-tained 50.0%, based on the dry weight, of the silicic acid. This product was cut into a length of l cm, and then, beaten by using a refiner and washed with water in a manner similar to that in Example 1. The pulp-like pxoduct so obtained contained only 27.8%, based on the dry weight, of the silicic acid.
Following the procedure set forth in Example 8, paper was manufactured from a 2:8 by weight mixture of the pulp-like product and wood pulp similar to that used in Example 8. The paper had a basis weight of 50.6 g/m2, a thickness of 98.0 microns, a bulk density of 0.52 g/cm3, a breaking strength of 2.90 km, a surface strength of below 2A, a whiteness of 86.2% and an opacity of 72.3%.
Obviously, this paper was inferior in strength, particularly surface strength, to paper manufactured from the fibrous product of the invention.
Examples 9 through 14 Following the procedure set forth in l~xample 2, fibrous products were prepared from the compositions *_registered trade mark B

108Z8~i1 shown in Table v, below, and then pulp-like products were prepared therefrom. The content of finely divided in-organic substance particles is shown in Table VI.

Table V
Polymer Compositions Used and their AmDunts Hydrophobic Hydrophilic finely Surface Example Polyolefin high ~W divided active Solvent Water No. compound inorganic agent substance (g)(g) (g) (g) (liter) (liter) 9 Poly- *1PVA *2 Silicic *5 Na salt of Hexane (1.8) propylene (6) acid ST/MA/MMA (1.2) (60) (60) copolymer (3) - do -- do - - do - - do - Petroleum - do -ether (1.2) 11 Poly- *3Na poly- *4 - do - - do - Hexane - do -ethylene acrylate (1.2) (60) (6) 12 - do -PVA (6) - do - - do - Methylene - do -chloride (1.2) 13 - do -- do - - do - Na dodecyl- - do - - do -benzene-sulfonate (3) 14 - do - - do - - do - - do -- do - 0.4 ~. .

' ,- . :

108Z8~1 Notes:
*l Trade name "MITSUI Noblene FL", supplied by Mitsui-Toatsu Co.
*2 Polyvinyl alcohol similar to that used in Example 1.
*3 Similar to that used in Example 1.
*4 Trade neme "Aron A-20(p)", supplied by Toa Gosei Kagaku Co.
*5 Similar to hydrophobic silicic acid specimen 13 used in Example 1.

Table VI
Inorganic substance content (%) Example No. in fibrous product in pulp-like product 9 47.6 45.2 47.1 45.0 11 46.8 44.6 12 47.0 45. 3 13 47.2 44.7 14 46.9 44.9 .. ~ . . .

Claims (19)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. An aggregate of a fibrous material used for a synthetic pulp essentially consisting of a surface active agent, a hydrophilic high molecular weight compound, a hydrophobic finely divided inorganic substance particle having an average particle size below 5 microns and an olefin polymer, said hydrophobic finely divided inorganic substance particle being effectively integrated with the polymer body of the fibrous material.

2. An aggregate of a fibrous material according to claim 1 wherein said surface active agent is at least one water-soluble copolymer selected from the group consisting of:
(1) a copolymer comprised of units derived from at least one monomer of the formula:

and units derived from at least one monomer of the formula:

where A represents a metal selected from the group consisting of Li, Na, 1/2Ca, 1/2Zn and 1/3A?; B represents a member selected from the group consisting of hydrogen, a hydrocar-bon radical having 1 to 20 carbon atoms, Li, Na, 1/2Ca, 1/2Mg, 1/2Zn and 1/3? ; R1 represents a member selected from the group consisting of hydrogen and a hydrocarbon radical having 1 to 30 carbon atoms; and R2 represents a member selected from the group consisting of hydrogen, -COOR3 (where R3 is hydrogen or a hydrocarbon radical having 1 to 30 carbon atoms), -OCOR4 (where R4 is a hydrocarbon radical having 1 to 20 carbon atoms), halogen or -CH2OH, and (2) a vinyl monomer-grafted polyvinyl alcohol.

3. An aggregate of a fibrous material according to claim 2 wherein said finely divided inorganic substance particle has an average particle size below 2 microns.

4. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said copolymer is a styrene-sodium maleate copolymer, a styrene-alkyl methacrylate-sodium maleate copolymer, an ethylene-sodium maleate copolymer or a hexene-sodium maleate copolymer.

5. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said copolymer is a styrene-grafted polyvinyl alcohol.

6. An aggregate of a fibrous material according to claim 1, 2 or 3 which comprises, in addition to the four ingredients, an oil-soluble surface active agent functioning as a dispersant for the hydrophobic finely divided inorganic substance particle.

7. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said hydrophobic finely divided inorganic substance particle is prepared by hydrophobization of a finely divided particle selected from silica, titanium oxide and calcium carbonate.

8. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said hydrophobic finely divided inorganic substance particle is prepared by hydrophobization of a finely divided particle selected from kaolin or talc.

9. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said hydrophilic high molecular weight compound is polyvinyl alcohol.

10. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said olefin polymer is selected from polyethylene, polypropylene and a copolymer of ethylene and propylene.

11. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein the ratio by weight of the hydrophobic finely divided inorganic substance particle to the olefin polymer is from 1/10 to 20/1.

12. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein the amount of the hydrophilic high molecular weight compound is from 0.1 to 50% by weight based on the total weight of the olefin polymer and the hydro-phobic finely divided inorganic substance material.

13. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein the amount of the surface active agent is from 0.05 to 10% by weight based on the weight of the fibrous material.

14. An aggregate of a fibrous material according to claim 1, 2 or 3 wherein said hydrophilic high molecular weight compound is disposed in a linear form of a continuous length or a short length in the fibrous material.

15. A process for preparing an aggregate of a fibrous material used for a synthetic pulp which comprises flushing an emulsion comprised of a surface active agent, a hydro-philic high molecular weight compound, an olefin polymer, a hydrophobic finely divided inorganic substance particle having an average particle size below 5 microns, water and a solvent for the olefin polymer and maintained at a tempera-ture of at least 100°C through an orifice of a nozzle into an environment of a lower pressure.

16. A process according to claim 15 wherein said emulsion is of an oil-in-water type.

17. A process according to claim 15 wherein said solvent for the olefin polymer is selected from the group consisting of a hydrocarbon having 5 to 7 carbon atoms, methylene chloride and trichloroethylene.

18. A process according to claim 15 wherein the olefin polymer and the hydrophobic finely divided inorganic sub-stance particle are present in a non-aqueous phase comprising the solvent at the total concentration of from 5 to 40% by weight based on the weight of the non-aqueous phase.

19. A process according to claim 15 wherein the hydro-philic high molecular weight compound is present in an aqueous phase and the amount of the hydrophilic high molecular weight compound is from 0.1 to 50% by weight based on the total weight of the olefin polymer and the hydrophobic finely divided inorganic substance particle.