CA1069661A - Polyolefin fibers containing basic pigments and process for preparing same - Google Patents

Polyolefin fibers containing basic pigments and process for preparing same

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Publication number
CA1069661A
CA1069661A CA246,609A CA246609A CA1069661A CA 1069661 A CA1069661 A CA 1069661A CA 246609 A CA246609 A CA 246609A CA 1069661 A CA1069661 A CA 1069661A
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Prior art keywords
pigment
polyolefin
basic
fibers
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
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CA246,609A
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French (fr)
Inventor
Wolfgang Gordon
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Hoechst AG
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Hoechst AG
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Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H5/00Special paper or cardboard not otherwise provided for
    • D21H5/12Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials
    • D21H5/20Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of organic non-cellulosic fibres too short for spinning, with or without cellulose fibres
    • D21H5/202Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of organic non-cellulosic fibres too short for spinning, with or without cellulose fibres polyolefins
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01DMECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00Formation of filaments, threads, or the like
    • D01D5/11Flash-spinning
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00General methods for the manufacture of artificial filaments or the like
    • D01F1/02Addition of substances to the spinning solution or to the melt
    • D01F1/04Pigments
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00General methods for the manufacture of artificial filaments or the like
    • D01F1/02Addition of substances to the spinning solution or to the melt
    • D01F1/10Other agents for modifying properties
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/02Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/04Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H13/00Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/10Organic non-cellulose fibres
    • D21H13/12Organic non-cellulose fibres from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H13/14Polyalkenes, e.g. polystyrene polyethylene

Abstract

POLYOLEFIN FIBERS CONTAINING BASIC PIGMENTS AND PROCESS
FOR PREPARING SAME
Abstract of the disclosure:
Hydrophilic polyolefin fibers containing more than 50 weight % of a basic pigment, are obtained if a mixture of poly-olefin, a solvent for this polyolefin, a basic pigment, a hy-drophilization agent, water and an organic acid flows from a pressure vessel through a nozzle into a low-pressure chamber.
The thus obtained fibers may be used for preparing synthetic paper without requiring much expenditure for work-up.

Description

~0696~1 HOE 75/F 056 It has been known for some time to produce polyolefin fibers containing pigments by adding "small amounts" of pigments and other insoluble compounds to a superheated polymer solution kept under pressure and to form fibers therefro~ by flash evaporation. When applying this process to polyolefins, hy-drophobic fibers are obtained of strictly non-hydrophilic properties, which greatly restrict their technical applica-tions. Moreover, no specific disclosures are given about pos-sibilities of producing fibers with higher pigment contents.
It may be assumed that "small amounts" mean at any rate less than 20% by weight, calculated on the total weight of the fibers (cf. DE-AS 12 92 301 to du Pont and published on April 10, 1969).
A similar process is described, in another specification how-ever, which provides for adding up to 50 weight % - calcualted on the fiber weight - of insoluble fillers. This latter process also produces hydrophobic fibers. However, said patent specification does not go into the details of the particular difficulties en-countered upon preparation of hydrophilic polyolefin fibers containing at the same time a high portion of filler (cf.
DE-OS 22 52 759 to Gulf Research and published on May 3, 1973).
There is also known a process for preparing polymer fibers by flash evaporation of an emulsion of a polymer solu-tion and an aqueous solution of a wetting agent, which also provides for adding pigments, though no refernece is made there to the particular difficulties of this operation and of keeping it under control (cf. DE-AS 21 21 512 to Toray Industries and published on November 18, 1971).
On ~le o~ler hand, it has not been made known yet how polyolefin fibers
- 2 -- - . - , . - , - . . -~06~6~

containing hydrophilic and basic pigments may be obtained. No mention is made there either of hydrophilic polyolefin fibers containing-mDre than 20 weight % let alone of polyolefin fibers containing even more than 50 weight ~ of a basic pigment.
A further process has been suggested for preparing hydro-philic polyolefin fibers containing pigments which provides for hydrophobizing the pigment prior to its application. Howe-ever, the hydrophobization is a complicated and expensive pro-cessing step (cf. DE-OS 24 24 291 to Hoechst AG and published on December 4, 1975).
A pmcess has ncw been found for preparing polyolefin fibers containing basic pigment, which comprises the flash evaporation of a superheated suspension kept at least under autogenous pressure and consisting of a) a basic pigment, b) an emulsion of a solution of a polyolefin in a readily boil-ing solvent for these polymers and of an aqueous solution of a hydrophilization agent, c) an organic acid, the flash evaporation being carried out through a nozzle in a low pressure zone.
Subject of the present invention is thus a process for preparing hydrc-philic polyolefin fibers containing basic pigment, by means of a flash evaporation of a superheated suspension kept at least under autogenous pressure, consisting of aa basic pigment and b) an emulsion of a solution of a polyolefin in a readily boiling solvent for these polymers and of an aqueous solution of a hydrophilization agent through a nozzle into a low pressure zone, which comprises that the suspension contains furthermore an organic acid, and ,~ .

- . . - . . .

:.

-- ~ ~ 9 6~ 1 HOE 75/F 056 the hydrophilic polyolefin fibers prepared according to this process.
A suitable polyolefin is a polyethylene with a reduced specific viscosity of 0.3 to 20 dl/g, preferably of 0.7 to 10 dl/g (determined according to H.Wesslau, Kunststoffe 49 ~1959) 230) and a density of from 0.9~ to 0.97 g~cm3. ~This polyethy-lene may contain minor amounts of comonomers having from 3 to 6 carbon atoms, the density of the copolymer has to range with-ln the limit of 0.93 to 0.97 g/cm3, preferably from 0.94 to 0.965 g/cm3. Further suitable polyolefins ~re homopolymers and copolymers of propylene, preferably containing an atactic por-tion of from O to 25 weight %, the best results being obtained with an atactic portion of from O to 6 weight %. Preference as copolymers of propylene is given to random copolymers having from 0.1-3 weight % of ethylene or from 0.1-2 weight % of buty-lene, but block copolymers with ethylene ~ well a~ random co-polymers with higher comonomer portions are also suitable.
Suitable hydrophilization agents are, in principle, all ~nown types of emulsifier, tho.ugh preference is given to poly-mer hydrophilization agents with amine groups, amide groups, carboxyl.groups and/or hydroxyl groups. Excellent results are ; especially obtained by polyvinyl alcohol having a viscosity of from 4 to 70 cp in a 4% solution in water at 20C and a degr~e of ~aponification of from 80 to 99.5%. The hydrophylization agent shall confer a good disperslbility in water upon the .
polyolefin fiber~ filled with basic pigment, so that same ~hell acquire good wetting properties and become readlly and uniform-ly dispersible in water.
-! :
~29 The solvent used for the polyolefin shall have a sufficient-.~ - 4 -.
.., ., : . . . , , . . ,- . . . .

. . .
~. . - -,, ~, .. . . . .

lC~9 6 ~ 1 HOE 75/F 056 ly low boiling point, so that satisfactory superheating and flash evaporation are possible and its critical temperature shall be sufficiently high. Therefore, in the process of the invention, there are suitable hydrocarbons thoJc having from 5 to 7 carbon atoms, preferably cyclic or acyclic saturated hydrocarbons having from 5 - 6 carbon atoms. ~ery good results can also be obtained with chlorinated hydrocarbons having one or two carbon atoms, preferably with methylene chloride.
The temperature of the suspension may vary within a range of from 110 to 200C, preferably from 120 to 160C. The sus-penslon is kept under the ~ pressure of the water-solvent-mlxture which may be increased by an inert gas and/or by pumping.
The suspension of a basic pigment and an emulsion formed ; 15 of a solution of polyolefin and a solution of the hydrophili-zatlon agent shall be as uniform as possible. This requirement can be met by discontinuous or continuous operation as well, provided that this suspension be prepared in commercial sus-pension and emulsion devices with good substance circulation and satisfactory shearing effect. The advantages of the process according to the invention appear as well with water-in-oil emulsions and wlth oil-in-water emulsions.
For flash evaporation the suspension passes through a nozzle, the most important assignment of which is to maintain ~j ~ 25 a pressure difference between suspens~on and flash chamber.
The pres~u~e in the flash chamber is ad~usted so as to evaporate more than 90% of the ~solvent used for the polymer. This eva-poratlon also~includes part of the wat~r, of course. The pre~-29~ ure snall generally range from 10 to 1500 mm ~g, preferably ... . .
, .~ .
: : . . .

1~966~ HOE 75/F 056 from 50 to 800 mm Hg. The pigment-containing fibers are essen-tially obtained moist with water and can be comminuted and de-hydrated in commercial devices.
Suitable basic pigments are inorganic compounds, the aque-ous suspension of which has a pH ranging from 8 to 12, such asoxides, hydroxides, carbonates and basic sulfates of metals of the second or third main group of the Periodic Table, or double salt~ of metals of the first, second or third main group o~
the Periodic Table and, optionally, of another metal. Suitable pigments are, for example, magnesium oxide, calcium hydroxide, aluminum hydroxide, hydrated or non-hydrated aluminum oxide, barium hydroxide, calcium carbonate, barium carbonate, basic aluminum sulfate and dolomite. The crystal structure or the degree of hydration of the pigment employed are of no impor-tance in that respect.
The particle size of the basic pigments employed mayvary widely. The pigments are most o~ten used ground to a particle diameter smaller than 50/um for 90% of the particles, preferably smaller than 10/um. Mixtures of two or several basic pigments can be employed as well.
The quantity of the basic pigment to be used may vary widely. The advantages of the process become especially evi-dent at ~0 weight % or more of pigment, preference is given to the use of bas~c pigment at the rate of 50 weight % to 90 weight %. A pigment portion of 90 weight ~ is usually the maxi-mum~ for the fibers become very short beyond this limit.
The chemical structure of the organic acid which is used for the proc~ss according to the invention may vary within a 29 wide r~nge. Carboxylic acids are su~table as well as sulfonic .
' ~ . , ' . ~ , :

-~96~ HOE 75/F 056 acids. Appropriate organic radicals of this acid are aliphatic, aromatic or alkylaromatic radicals which may be non-cyclic, monocyclic or bicyclic. The number of said acid groups and their position to each other are of minor importance for the process of the invention. Preference is given to terminal monocarboxylic acids and monosulfonic acids having one organic radical which contains from 3-30 carbon atoms, preferably from 8 - 20 carbon atoms. Accordingly, there are preferably used dicarboxylic acids having from 6 - 20 carbon atoms and polymer compounds containing carboxyl groups having an acid number of from 50 to 500 mg of KOH/g. The organic acids employed may also contain different functional groups and heteroatoms, additionally to carboxyl groups or sulfonic acid groups, however, the advantages of the process according to the invention decrease more and more with increasing po~larity of these functional groups and hetero atoms.
Mixtures of various acids may be used as well, e.g. mixtures of fatty acids of different chain lengths and different numbers of double bonds, such as same occur with technical processes.
Preferably used organic acids are, for example, benzoic acid, benzosulfonic acid, naphthalene-carboxylic acid-(l), naphthalene-dicarboxylic acid-(1,2), naphthalene sulfonic acid-(l), naphthalene sulfonic acid-(2), adipic acid, lauric acid, palmitic acid, oleic acid, wax oxidates having an acid n~mber of 50-500 mg of KOG/g and acid wax ha~ing an acid number of 50-500 mg of KOH/g.
The quanti~y of organic acid employed depends somewhat on its chemical structure. As a rule, there are applied from 0.1 28 to 10 weight % of organic acld~ calculated on basic pigment, .~: , : , , - ' :

---` ` ` 1069661 HOE 7 5 /F 0 5 6 preference is given to the range from 0.5 to 5 weight %.
The concentration of organic acid in the suspension varies from 0.02 to 20 g/l, depending on what content in basic pigment in the fiber is aimed at and depending on the kind and S quantity of hydrophilization agent. The residence time of organic acid in the emulsion is normally 10 seconds or more, preferably longer than 2 minutes. Extremely long residence periods do not alter the effect of the acid.
The acid-containing pigment suspension of a basic pig-ment and an emulsion formed of a solution of a polyolefin in anaqueous solution of a hydrophilization agent may be prepared according to known processes. The organic acid can be added to the suspension continuously or discontinuously e.g. in its pure liquid state or dissolved in the solvent for the polymer.
The acid-con~aining suspension may be prepared as well in a different order. One possibility is e.g. to add the organic acid to the polyolefin solution, to suspend the pigment in this mixed solution and to emulsify this suspension with the aqueous solution of the hydrophilization agent; or a solution of poly-olefin in organic acid may be mixed e.g. with an aqueous suspen-sion of basic pigment and an aqueous solution of the hydrophiliza-tion agent, while emulsifying.
A discontinuous operation method calls for charging into a cold pressure vessel preferably polyolefin, basic pigment and organic acid in its pure state and hydrophilization agent pure or dissolved, as well as water and a solvent for the polymer in any order of succession and to prepare the suspension by 28 heating together all components and stirring thoroughly.

- - . - - .

::

~ ~ HOE 75/F 056 0696~1 A continuous operation method provides for preparing preferably a suspension consisting of the essential quantity of pigment in a solution of organic acid, in the solvent for the polymer, for diluting with this suspension a concentrated poly-olefin solution - or for diluting a concentrated polyolefin suspension which is then heated ~or dissolution of the polyolefin.
The thus obtained suspension of basic pigment in a solution of polyolefin and organic acid is then blended to form an emulsion with an aqueous solution of the hydrophilization agent and with an aqueous suspension of a comparably small amount of pigment in water which is recycled after comminution of the fibers and mechanical partial dehydration.
All embodiments dispense with an isolation of hydropho-bized basic pigment requiring an expensive drying step. It is the surprising re~sult of the experiments and a special advantage of this process that this isolation is not necessary.
The use of hydrophilic basic pigments brings about considerable technological complications unless organic acids are added. Experiments showed that only part of the hydropilic basic pigment is incorporated into the fibers and thus covered at least by a polyolefin skin. About 40 - 70% of the hydrophilic pigment occurs in the original powdery form and is washed off with the water upon the mechanical partial dehydration of the fibers. Therefore, quite expensive and complicated separating and recycling devices for important quantities of pigment are required so as to avoid losses. Another part of the pigment ~`l adheres only loosely to the fibers.
When comminuting the fibers, an operation which may be 29 carried out in co~mercial fiber comminution devices, the ad-., ~ .
. 9 :.
,~.. ...................................................... . .
.
.. . .
: : .

.
. . .

- ~0696~1 HOE 75lF 056 hering pigments are detached from the fibers and get lost again, unless they are recycled to a large extent. Moreover, the di~-persion of basic pigment in the fibers is quite irregular, so that a relatively large number of short fibers is particularly rich in pigment. When being used for the manufacture of paper sheets, sa~d short fibers pass through the sieve and pollute the waste water and thus create waste water disposal problems for the paper manufacturing industry, unless this portion is recovered.
It ~s surprising that the above mentioned problems do practically not arise upon application of the process accord ing to the invention. The hydrophilic basic pigment is incor-porated uniformly and almost completely into the polyole~in fiber. Therefore, the losses during flash evaporation, fiber comminution or paper manufacturing are small. These advantages emerge more and more with an increasing concentration rate of basic pigment in the fiber. In case that more than 35 weight %
of hydrophilic basic pigment shall be incorporated into the fibers, the difference between the process of the lnvention and a processing method without organic acid has grown to such an extent that the expenditure would become prohibitive. In fact, the process according to the invention ena`oles for the first time the preparation of fibers of polyolefin having more than 50 weight % of pigment, calculated on the fiber weight.
The process according to the inYention has the further advantage that upon flash evaporation the fiber~ are obtained in a very uniform and short form at pigment contents of 50 weight ~ and more (calcula~ed on the total weight of pigment 29 and polyolefin), 80 that inmost of the cases a ~rther comminu-.. . .. .. . i . ~ . . . . . . .... . .

-- 106~6~1 HOE ~/F 0~6 tion of the fibers or homogenization of the fiber length can be dispensed with. None of the known means can achieve this effect without any pigment, even though very low polymer concen-tration rates may be applied.
HydrDphilic polyolefin fibers containing from 50 - 90 weight % of basic pigment may be employQd as fibrous fillers in all fiber non-wovens. In comparison to non-fibrous fillers, they have the Pdvantage of a better retention upon preparation of these non-wo~ens. So as compared with hydrophilic polyole-fin fibers without basic pigment, their advantage resides in their better covering capacity in a non-woven~ For example, calendered paper containing the fibers according to the inven-tion is more opaque than calendered paper containing known polyolefin fibers. The hydrophilic character of the pigment-containing fibers is necessary for enabling the procesqing of the fibers from an aqueous suspension - e.g. in paper industry.
j The following examples and drawing illustrate the advan-tages of the process and the fibers according to the invention:
E X A M P ~ E 1:
Into an autoclave A ( see fig.) ha~ing a volume of 70 l and being equipped with a five-blade-multistage-impulse-counter-current stirrer B, are charged 0.6 kg of polyethylene (density 0.960 g/cm3, reduced specific viscosity 1.4 dl/g, molecular , weight distribution MW/Mn-6),20 l of hexane, 15 l of water, a solution of 40 g of polyvinyl alcohol (~iscosity of a 4% solu-tion in water at 20C: 4 cp, degree of saponification: 98%) in 400 ml of water, 2.4 kg of calcium carbonate with 90% of the part1~es having a size smaller than 8 /um,as well as 72 g of . i :
;~ ~ 29~ indu~trial stearic acid at 140C being d~ssolved together at . . .
~:; . . , . .: .
~, , , .. , ..' ~ ', , .... . , ~

1069661 HOl~ 75/F 056 600 rpm of the stirrer, emulsifiea and suspended. The allover pressure in the vessel is adjusted to 16kg/cm2. After having opened the dump valve C, the emulsion flows through a tubular nozzle D having an interior diameter of ~ mm and a length of 1.20 m into a receptacle E, wherein a vacuum pump F maintains a pressure of about lO0 mm Hg and where the produced fibers are collected. Residual hexane which remained in the fibers is evaporated by conducting steam over the fibers from the steam line H, under vacuum. The aqueous fibers are removed from the vessel E through the orifice G which can be sealed.
The produced fibers contain - after partial dehydration by mechanical compression to about 30% of fiber content - 76.7%
of the empolyed calcium carbonate, i.e. the retention upon the flash evaporation step amounts to 96.0%. The obtained fibers have a hydrophilic character and are easily dispersible in water.
; If 2 g of these fibers are dispersed uniformly in a 1 liter measuring cylinder in 800 ml of water by shaking repeatedly, and if this fiber suspension is allowed to stand for exactly 2 minutes, the fibers sink slightly so that the supernatant water free from fibers assumes a volume of 30 ml.
If the thus obtained fibers are subjected to a diaphragm classified according to Brecht-Holl for lO min./sieve under a water pressure of 0.5 atmosphere gauge and maximum lift, a quantity of 2 g is retained by 32% on a sieve having a mesh - 25 width of 0.~ mm, 59% were retained on a sieve with a m~sh width of 0.12 mm, whilst 9% passed through this latter sieve. This result showed that the fibers were uniform and short, so that they may be used e.g. in thepaper manufacturing industry without 29 any additional co~minution.

. . , . . ~ ~, . . .. .
. . . , ~ . . . - :

- : : . ,.: : - ..

When a paper sheet weighing 160 g/m2 was formed on a Rapid-Kothen Sheet-Former from the fibers obtained by Example 1, this sheet contained 73% of pigment, i.e. 95~ of the pigment was retained during the fiber processing step. For all process-ing steps, comprising fiber-forming and fiber-processing, the retention of pigment amounted to 91.4%~ On the other hand, when trying to prepare a pigment-containing sheet of 75% of hydrophilic pigment and of 25% of comparable polyethylene fibers which do not contain any pigment, the pigment was retained at a rate of only 21%.
_MPARATIVE EXAMPLE A:
The process is the same as described in Example 1, with the exception that no stearic acid is added.
; The produced fibers contain 43% of calcium carbonate after partial dehydration by mechanical compression to a fiber content of about 30%.
When these fibers are classified according to Example 1, 89% are retained on a sieve having a mesh width of 0.40 mm, 9% on a sieve having a mesh width of 0.12 mm and 2% of the fibers pass through this latter sieve. Though these fibers are well hydrophilic, they are not freely dispersible as a diluted suspension, but still cling together.
The fibers reach a length comparable to that of example 1 only after two comminutions in a 12" disk refiner of Messrs.
Sprout-Waldron in known manner. The classification then results in 25% being retained on a 0.40 mm sieve, 62% retained on a 0.12 mm sieve and 13% passing through the 0.12 mm sieve. After a partial mechanical dehydration as described the content in 29 calcium carbonate was only 36~, representing a pigment re-. . . .
.
' ,: ': ~ ' , .

: -' : ' . '' ~ ~ ' :
' .

~ ~ 9 6 6 ~ HOE 75/F 076 tention of 45~ in the prep~ration of fibers.
If a sheet weighing 160 g/m2 is formed on a Rapid~gothen Sheet-Former from the thus comminuted fibers, this sheet con-tains only 32% of calcium carbonate, i.e. the pigment re-tention from the fiber preparation to the fiber processing amounts to ~nly 40%. It appears to be impossible to obtain by this manner hydrophilic fibers containing more than 50% of pigment. The pigment quantities which are not retained have to be recovered and fed back into the circuit by complicated ~0 and costly means.
E X A M P ~ E 2 with COMPARATIVE EXAMP~E B:
In the same way as described in Example 1 there are emul-sified and suspended 1.2 kg of polyethylene (reduced specific viscosity 3.4 dl/g, MW/Mn6, density 0.945 g/cm3 by statistical copolymerization of ethylene with butene), 20 l of cyclohexane, 10 l of water, a solution of 50 g of polyvi.nyl alcohol in 0.5 l of water and 0.8 kg of dolomite (particle size d50 = 2/um) and 16 g of naphthalene-sulfonic acid-(2). Fibers are prepared by flash-evaporation, which are then comminuted in a disk re-finer in three comminution operations.
The parallel test is run without the use of naphthalene-sulfonic acid-(2), and the prepared primary fibers are commi-nuted under identical conditions in 5 comminution steps. Table 1 shows the obtained fiber length distribution as being car-ried out accordlng to Example 1, as well as the pigment con-tents after flash evaporation, after comminution and after formation of a ~heet according to Ex~mple 1.
.

.. ,. , . - . . ................. . - . . .
~ . : ... . , . . . . . -~ : ' ~. . ' -' ' : -~

" ~069661 T A B ~ E ?

Pigment without naph- with napth-thalene sul- thalene sul-fonic acid-(2) fonic acid-(2) . . _ . .

Dolomite - applied ) 40 40 % Dolomite1) after flash evaporation 21 ~8 % Dolomite1) after comminution 17 36.5 % Dolomite1) in the sheet 13 34 1 0 FlberB
% retained on 0.40 mm sie~e 17 22 % retained on 0 12 mm sieve 61 56 % passed thorough 0.12 mm sieve 22 22 1) % of pigment calculated on the weight of dolomite and poly-ethylene E X A M P L E 3 with COMPARATIVE EXAMP~E C:
1.0 kg of polypropylene (reduced specific viscosity:
2.3 dl/g, ~.3% of heptane-soluble portions (12 hours in a soxh-.let apparatus), 20 l of isopentane, 20 l of water, a solution of 60 g of polyvinyl alcohol ( viscosity of the solution of 4 g/l in water at 20 C: 66 cp, degree of saponification: 99%) in 600 ml of water, 1.0 kg of aluminum oxide trihydrate (par-ticle si7.e d50 = 0.8/um) and 25 g of acid wax (acid number 145 mg of KOH/g, saponification number: 165 mg of KOH/g, drop-ping point:81C) which had been obtained from montan wax by chromic acid oxidation, was emulsified and suspended. By sub-: . sequent fl&~h e~aporation unde~ the conditions of Example 1, ;~ 29 except for the pressure being here 25 kg/cm2 above the ~us-~ - ~5 -.

... - - ~ ~ .

-` ~069~61 HOE 75/F 056 pension and a pressure of 250 mm Hg in the flash chamber -there are prepared polypropylene fibers, then comminuted in one stage in a disk refiner. The comparative test is carried out without acid wax, whereby the fibers formed during the flash evaporation are comminuted in two stages. Table 2 shows the contents in pigment and the classification analysis.

T A ~_~ E 2 Pigment without with acid acid wax wax % Pigment applied 50 50 % Pigment after flash evaporation 21 4~
% Pigment after comminution 17 40.5 % Pigment after sheet formation 15 38 -Fibers % retained on 0.40 mm sieve 17 19 % retained on 0.12 mm sieve 64 55 % passed through 0.12 mm sieve 19 26 . . .
(% of pigment calculated on the total weight of pigment and polypropylene).

; .

~ - 16 -: . - . . .. .

Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of hydrophilic polyolefin fibers containing basic pigment, in which a superheated suspension which is at least under autogenous pressure and is composed of a) up to 90% of a basic pigment, b) an emulsion of a solution of a polyolefin in a readily boiling solvent, said solvent being selected from the group of hydrocarbons having from 5 to 7 carbon atoms and chlorinated hydrocarbons having 1 or 2 carbon atoms, for the polyolefin and an aqueous solution of a hydrophilization agent, and c) 0.1 to 10 weight %, per part of basic pigment, of an organic acid, having from 3 to 30 carbon atoms, based on the amount of pigment, the concentration of the acid in the suspension being in the range of from 0.02 to 20 g/1, is subjected to flash evaporation through a nozzle into a low pressure zone having a pressure of from 10 to 1500 mm Hg.
2. A process as claimed in claim 1 in which the polyolefin is polyethylene having a density of 0.93 to 0.97 g/cm3.
3. A process as claimed in claim 1 in which the polyolefin is polypropylene having an atactic portion of from 0 to 25%.
4. A process as claimed in claim 1, claim 2 or claim 3 in which the hydrophilization agent is polyvinyl alcohol.
5. A process as claimed in claim 1, claim 2 or claim 3 in which the solvent is a saturated hydrocarbon having S or 6 carbon atoms or methylene chloride.
6. A process as claimed in claim 1, claim 2 or claim 3 in which the suspension, prior to flash evaporation, is at a temperature of from 110 to 200°C.
7. A process as claimed in claim 1, claim 2 or claim 3 in which 90 weight % of the particles of the basic pigment are smaller than 50 µm.
8. A process as claimed in claim 1, claim 2 or claim 3 in which the basic pigment is selected from the group of mag-nesium oxide, calcium hydroxide, aluminum hydroxide, aluminum oxide, barium hydroxide, calcium carbonate, barium carbonate, basic aluminum sulfate and dolomite.
9. A process as claimed in claim 1, claim 2 or claim 3 in which the organic acid is selected from the group of alipha-tic, aromatic and alkyl-aromatic carboxylic acids and sulfonic acids having from 8 to 20 carbon atoms and polymer compounds containing carboxyl groups having an acid number of from 50 to 500 mg of KOH/g.
10. A process as claimed in claim 1, claim 2 or claim 3 in which from 0.5 to 5 weight % of organic acid is used per part of basic pigment.
11. Hydrophilic polyolefin fibers containing a basic pigment in an amount of from 50 to 90 weight %, the basic pig-ment being an inorganic compound the aqueous suspension of which has a pH of from 8 to 12, whenever obtained according to a process as claimed in claim 1, claim 2 or claim 3.
CA246,609A 1975-02-27 1976-02-26 Polyolefin fibers containing basic pigments and process for preparing same Expired CA1069661A (en)

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DE2508455A DE2508455C2 (en) 1975-02-27 1975-02-27 Process for the production of hydrophilic polyolefin fibers containing basic pigment

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CA1069661A true CA1069661A (en) 1980-01-15

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JP (1) JPS51109324A (en)
AU (1) AU498922B2 (en)
BE (1) BE839031A (en)
CA (1) CA1069661A (en)
CH (1) CH596331A5 (en)
DE (1) DE2508455C2 (en)
DK (1) DK82576A (en)
ES (1) ES445386A1 (en)
FI (1) FI760495A (en)
FR (1) FR2302355A1 (en)
GB (1) GB1523501A (en)
GR (1) GR60055B (en)
IT (1) IT1055903B (en)
LU (1) LU74428A1 (en)
NL (1) NL7601745A (en)
NO (1) NO760653L (en)
PT (1) PT64846B (en)
SE (1) SE7602342L (en)
ZA (1) ZA761176B (en)

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Publication number Priority date Publication date Assignee Title
CA2017782A1 (en) * 1989-06-01 1990-12-01 James H. Harrington Rewettable polyolefin fiber and corresponding nonwovens
US5033172A (en) * 1989-06-01 1991-07-23 Hercules Incorporated Rewettable polyolefin fiber and corresponding nonwovens
US6162538A (en) * 1992-11-24 2000-12-19 Clemson University Research Foundation Filled cut-resistant fibers
US5851668A (en) * 1992-11-24 1998-12-22 Hoechst Celanese Corp Cut-resistant fiber containing a hard filler
US5464687A (en) * 1992-12-07 1995-11-07 Lyondell Petrochemical Company Wettable polyolefin fiber compositions and method
US5614574A (en) * 1994-07-12 1997-03-25 Lyondell Petrochemical Company Wettable polyolefin fiber compositions and method
US5767189A (en) * 1996-05-31 1998-06-16 E. I. Dupont De Nemours And Company Durable hydrophilic polymer coatings
US7338916B2 (en) * 2004-03-31 2008-03-04 E.I. Du Pont De Nemours And Company Flash spun sheet material having improved breathability

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3554683A (en) * 1966-06-18 1971-01-12 Asahi Chemical Ind Polyolefin composition excellent in dyeability
FR2109581A5 (en) * 1970-05-04 1972-05-26 Toray Industries
US3770856A (en) * 1970-09-08 1973-11-06 Oji Yuka Goseishi Kk Production of fine fibrous structures
JPS497095B1 (en) * 1970-09-25 1974-02-18
JPS5142617B2 (en) * 1971-11-12 1976-11-17
US4001035A (en) * 1974-01-16 1977-01-04 Dainichiseika Color & Chemicals Mfg. Co., Ltd. Coloring composition
DE2424291C3 (en) * 1974-05-18 1978-09-21 Hoechst Ag, 6000 Frankfurt Process for the production of hydrophilic polyolefin fibers containing inorganic pigment

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GR60055B (en) 1978-04-04
FR2302355B1 (en) 1980-05-30
PT64846A (en) 1976-03-01
FI760495A (en) 1976-08-28
DK82576A (en) 1976-08-28
AU498922B2 (en) 1979-03-29
JPS51109324A (en) 1976-09-28
DE2508455C2 (en) 1982-07-01
IT1055903B (en) 1982-01-11
CH596331A5 (en) 1978-03-15
NL7601745A (en) 1976-08-31
US4098757A (en) 1978-07-04
DE2508455A1 (en) 1976-09-02
SE7602342L (en) 1976-08-30
NO760653L (en) 1976-08-30
PT64846B (en) 1977-09-06
GB1523501A (en) 1978-09-06
LU74428A1 (en) 1977-01-07
ES445386A1 (en) 1977-06-01
FR2302355A1 (en) 1976-09-24
AU1144276A (en) 1977-09-01
BE839031A (en) 1976-08-27
ZA761176B (en) 1977-03-30

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