US3161706A

US3161706A - Method and apparatus for wet spinning elastomeric polymers into a fused multifilament fiber

Info

Publication number: US3161706A
Application number: US141530A
Authority: US
Inventors: Jr Timothy V Peters
Original assignee: Polythane Corp
Current assignee: Polythane Corp
Priority date: 1961-09-28
Filing date: 1961-09-28
Publication date: 1964-12-15
Anticipated expiration: 1981-12-15
Also published as: FR1361981A; BE633256A; NL291293A; NL132223C

Description

Dec. 15, 1964 T. v. PETERS, JR 3,161,706 METHOD AND APPARATUS FOR WET smmmc ELASTOMERIC v POLYMERS INTO A FUSED MULTIFILAMENT FIBER Filed Sept. 28, 1961 2 Sheets-Sheet l INVENTOR TIMOTHY V. PETERS, Jr.

m M, M

I Mm ATTORNEYS Dec. 15, 1964 1-. v. PETERS, JR 3,161,706

METHOD AND APPARATUS FOR WET SPINNING ELASTOMERIC POLYMERS INTO A FUSED MULTIFILAMENT FIBER Filed Sept. 28. 1961 2 Sheets-Sheet 2 Emma-7' ATTORNEYS PM, M, 70127,-

United States Patent 1 WTHQD AND APPARATUF: FGR WET SEHNNTNG ELASTOMERIC PQLYMERS INTG A FUSED MUL- TTFILAMENT FEBER Timothy V. Peters, in, Barrington, RL, assignor, by

mesne assignments, to Polythane Corporation, Rumford, RL, a corporation of Delaware Filed Sept. 23, 1961, Ser. No. 141,530 7 Qlairns. (Cl. 264-103) This invention relates to a method and apparatus for the wet spinning of filaments from solutions of elastomeric polymers commonly referred to as polyurethanes.

Wet spinning of elastomeric polymer solutions involves the extrusion of an elastomeric polymer solution through an orifice into a coagulating bath. The filament is formed as the solvent difiuses out into the coagulating bath. This diffusion is generally accompanied by the penetration of the coagulating bath liquid into the filament.

The spinning of isocyanate modified dihydroxy elastomeric polymer solutions by the wet spinning process has not been particularly successful. The filaments produced by this process have been weak and have not possessed desirable properties. As a result of the failure of the wet spinning process to produce filaments having acceptable properties, the isocyanate modified dihydroxy elastorneric polymer solutions have been transformed into filaments by a dry spinning process. The dry spinning process, however, is recognized as being quite expensive. It is also recognized that a wet spinning process, if it could be used to produce filaments having acceptable properties, would be much more desirable since it has numerous known advantages such as high productivity, low operating temperatures, large spinning orifices and so forth.

This invention involves a Wet spinning process for preparing isocyanate modified dihydroxy elastomer fibers possessing the same excellent properties as those fibers obtained from the more expensive dry spinning process.

The invention broadly involves the extrusion of an isocyanate modified dihydroxy elastomeric polymer solution through suitable spinnerets or extrusion nozzles into a liquid coagulating bath to form filaments. A plurality of the filaments are then gathered together and passed through a restricted area so that the pressure applied to them will press them together and consolidate them into a fused multi-filament fiber. While the filaments are being pressed together they are in contact with the coagulating fluid and are in a state of semi-plastic fiow. The multifilament fiber is then subjected to a twisting action while it is in contact with the coagulating fluid and also in a state of semi-plastic flow. The twisting action which is imparted to the multifilament fiber is in the nature of a socalled false twist. This twisting action can be imparted to the multifilament fiber by causing it to roll over a smooth surface. The resulting multifilamen't fiber is then dried and wound on a spindle ready for subsequent use in the formation of various garments or wearing apparel.

The solutions of isocyanate modified dihydroxy elastomeric polymers can be prepared by various manners known in the art. The term elastomeric polymer has been used herein to describe solutions of isocyanate modi ficd dihydroxy compositions which are capable of being extruded into a coagulating bath to form filaments or other shaped objects. The isocyanate modified compositions which can be extruded into a coagulating bath to form filaments have been referred to in the prior art in various manners such as prepolymers, semi-polymers and so forth. The term elastomeric polymer as used herein is intended to include all such extrudable isocyanate modified compositions.

Advantageously, the elastomeric polymers used according to this invention are prepared by reacting a difuncice tional hydroxyl terminated polymer with a molar excess of an organic diisocyanate to produce a low molecular weight isocyanate terminated prepolymer. The prepolymer can then be reacted with a compound containing, in general, at least two active hydrogens in the presence of a solvent to form a solution containing the resultant elastomeric polymer.

Various difunctional hydroxyl-terminated polymers including polyether glycols and polyester glycols can be used to form the prepolymers according to this invention. The molecular weight of the difunctional hydroxyl-terminated polymers can advantageously be maintained above about 700 and preferably between about 1,000 and 4,000. Difunctional hydroxy terminated polymers having a molecular weight below about 700 can also be used, but they generally do not result in end products having elasticity as advantageous as from those hydroxy polymers of big or molecular weight. The value of such products produced with hydroxy polymers having a lower molecular weight will depend upon the end use of the product and the elasticity desired for that particular use. Generally, as the molecular weight of the hydroxy polymer is decreased, the elongation decreases and the modulus increases. The use of a polymer having a molecular weight in an excess of about 4,000 presents considerable diificulties in the subsequent formation of the polymer solu tion and the transformation of such solutions into suitable and useful products due to difiiculties in maintaining acceptable rheological properties in the resulting polymer solutions.

The high molecular weight polyester glycols which can be used according to this invention are those which contain terminal hydroxyl groups. The esters can be prepared by various known methods by reacting diacids, diesters, or diacid halides with glycols. Suitable glycols which can be used to prepare the polyester glycols include polyalkylene glycols such as methylene, ethylene, propylene and butylene glycols. Substituted polyalkylene glycols such as 2,2-dimethyl-1,3-propene diol as well as heterocyclic glycols such as cyclohexanone can also be used. Examples of acids which can be used to prepare the polyester glycols include succinic, adipic, suberic, sebacic, terephthalic, as well as various alkyl and halogen substituted derivatives of the acids. The polyester glycol may for example be prepared by reacting the proper molar ratio of the acids or ester-forming derivatives of the acids with the glycols to produce the high molecular weight polymers. The polyester glycols prepared by reacting 2 mols of polyethylene glycol or polypropylene glycol with 1 mol of adipic acid and then removing the glycol with heat and vacuum until a molecular weight of about 2,000 is reached can advantageously be used to form prepolymers according to this invention.

The polyether glycols which can be used to form the prepolymers according to this invention are polyalkylene ether glycols having terminal hydroxy groups. The polyalkylene ether glycols can be prepared in known manners and are generally prepared by the polymerization of cyclic others such as alkylene oxides or from condensation of glycols. The polyalkylene ether glycols are represented by the formula HO(RO),,H in which R is an alkylene radical and n is an integer sufficiently large so that the polyalkylene glycol has a molecular weight in excess of about 700 and preferably in excess of about 1,000. The polyalkylene glycols can be prepared by copolymerizing mixtures of differen talkylene oxides or glycols. Examples of polyalkylene ether glycols which can be used in this invention include polypropylene ether glycol, polytetramethylene ether glycol, polyethylene ether glycol, l,2-polydimethylethylene ether glycol, polydecamethylene ether glycol, and so forth. Further examples 3 of polyalkylene ether glycols which can be used according to this invention are described in Patent No. 2,492,959.

Various organic diisocyanates can be used to react with the difunctional hydroxy polymers to form the prepolymer. Aromatic, aliphatc, as well as cycloaliphatic diisocyanates or combinations thereof, can be used. Representative diisocyanates include 4-methyl-m-phenylene diisocyanate, m-phenylene diisocyanate, 4,4'-biphenylene diisocyanate, methylene bis (4-phenylisocyanate), 4-chloro-1,3-phenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-methylene-bis(cyclohexylisocyanate), and 1,5 tetrahydronapthalene diisocyanate. Arylene diisocyanates, i.e., those in which each of the isocyanate groups is attached directly to an aromatic ring are preferred. In general, they react more rapidly than do the alkylene diisocyanates. The diisocyanates may contain other substituents, although those which are free from reactive groups other than the two isocyanate groups are ordinarily preferred. In the case of the aromatic compounds the isocyanate groups may be attached either to the same or to diiferent rings. Dimers of the monomeric diisocyanates and di(isocyanatoaryl)-ureas, such as di( 3-isocyanate-4-methylpheny1) urea may also be used.

The patents to Frankenburg No. 2,957,852, Windemuth No. 2,948,691 and the Hill No. 2,929,800 further show how the prepolymers can be prepared, as well as the reactants used in their preparation according to this invention.

The prepolymer is advantageously reacted with a compound containing at least 2 active hydrogens, such as a :liamine, in the presence of a solvent to form a solution containing the resultant elastomeric polymer. The amount of diamine used can advantageously be stoichiometrically equivalent to the amount of prepolymer used, but even more or less than the amount can be used. Generally, it is advisable to use sufiicient diamine so that the viscosity 3f the resulting elastromeric polymer solution will have 1 viscosity of at least 50 poises or, advantageously, a viscosity between about 100 to 500 poises.

In general, the amount of diamine that can be used form the elastomeric polymer solution can be varied :onsiderably depending on a number of factors such as he particular diamine used to react with the prepolymer, :he reactants used to form the prepolymer, the properties lesired to he possessed by the end products and so forth. these and other factors will be apparent to those skilled n the art and the exact amount of diamine that can most rdvantageously be used to prepare the polymer can be 'eadily determined by those skilled in the art by routine :xperimentation.

Various primary and secondary diarnines can be used 0 form the elastomeric polymers according to this invenion including aliphatic, allocyclic and inorganic diamines. lpecific examples of a number of diamines which can be rsed are hydrazine, ethylene diamine, piperazine, 1,4dimino-2-methyl piperazine, 1,4-diamino-2,5-dimethyl pi- IeraZine, methylimino bis propylamine, etc. It should also e apparent to those skilled in the art that combinations f two or more diamines may be used in the polymer. doreover, as already known in the art other compounds an be used which have active hydrogen atoms present 11 at least two atoms of oxygen and/or nitrogen, i.e. mine, carboxyl or hydroxyl groups, as fully described in LS. Patent 2,917,489.

Various solvents can be used to form the elastomeric olymer solutions, as will be apparent to those skilled 1 the art, such as dimethyl formamide, dimethyl sulfoxle, dimethyl acetamide, etc. Advantageously, a ratio f 1:1 to 6:1 of the solvent to the polymer can be emloyed.

The coagulating bath, which is generally Water, into hich the elastomeric polymer solution is extruded, builds 9 its solvent content during the process due to extraction of the solvent from the elastomeric polymer solution. The extraction of the solvent initially takes place when the filaments are gathered together and pressure applied to the filaments to consolidate them into a fused multifilament fiber. The pressure can be applied by any suitable means known to those skilled in the art such as pulling the filaments, under tension, down toward the apex of V-shaped grooves which have been cut in rollers, as shown in the drawing, or by leading the filaments through any suitable restricted area so as to press the filaments together into the multifilament fiber. The solvent which builds up in the coagulating bath can be continuously removed during the process to maintain, advantageously, the solvent content at a desirable level, e.g. 40-60% solvent.

In the formation of filaments, the extrusion speeds 0btainable will depend upon the bath temperature, the length of the bath, etc. Extrusion speeds of 150 feet per minute and higher have been obtained using a bath approximately 6 feet in length. The 150 feet per minute extrusion speed referred to above is not limiting since higher extrusion speeds can be obtained. The temperature at which the chamber is maintained and the length of time in which the filaments, or the multifilament fibers, are exposed to this temperature will vary depending upon the particular operating conditions employed, the particular composition of the elastomeric polymer solution, and so forth. The most suitable time-temperature relationship for each operation is a matter which can readily be determined by one skilled in the art.

The invention can more readily be understood by referring to the accompanying drawing which represents specific embodiments of the invention but which is not intended in any way to limit the scope of the invention.

in FIGURE 1, which is a top View of a spinning apparatus, an elastomeric polymer solution is extruded through a spinneret ll, into coagulating bath 2, to form a plurality of filaments 3. These filaments are then passed over roll 4 and under roll 5 within the V-shaped grooves of each roll, 6 and 7 respectively. Roll 5 is beneath roll 4 and parallel thereto. The V-shaped grooves gather the filaments together and consolidate them into a fused multifilament fiber 8. As can readily be understood, the multifilament fiber will be more tightly fused when the filaments are more firmly pressed toward the apex of the V-shaped grooves as the fiber is under tension.

The multifilament fiber 8 is then passed over roll 9 and under roll it) within the V-shaped grooves of each roll, 11 and 12 respectively. Roll lltl is beneath roll 9 and parallel thereto. Rolls 9 and it are laterally displaced with respect to rolls 4 and 5 so that when the multifilarnent fiber is drawn to the V-shaped grooves of

rolls

9 and 10, it will tend to roll down the sides of the grooves, thus forming a twisted fiber 13. This twisting action on the fiber efiects substantially complete consolidation or fusion of the filaments of the fiber and impants a roundness thereto. The

rolls

9 and 10 are laterally displaced at a distance that can be readily adjusted by routine experimentation to determine the most suitable displacement distance. A lateral displacement which results in the multifilament fiber leaving roll 5 at an included angle of about (depending on the angle of the groove 11) with respect to the axis of rotation of roll 5 may be employed. The sides of the V-shaped grooves of course can be concave or convex if desired and the angle of acuteness of the V-shape, as well as the extent of the lateral displacement can readily be adjusted with relation to each other to provide any suitable degree of twisting action desired.

FIGURE 2 shows a side View of FIGURE 1.

FIGURE 3 shows a more detailed View of roll 5 where the filaments have been gathered together to form the fused multifilament fiber 8.

FIGURE 4 shows a top view of a spinning apparatus wherein the

rolls

9 and 10, instead of being laterally displaced and parallel to rolls 4 and 5, are placed at an angle with respect to rolls 4 and 5. This angle, as determined by the axis of the respective rolls, may be about 15 (depending on the angle of groove 11) or any other suitable angle which can readily be determined by routine experimentation so that the fiber will be subjected to a twisting action as it passes within the V-shaped grooves 11 and 12 of

rolls

9 and 10.

FIGURE shows a more detailed view of roll 9 where the fiber tends to roll down the side of V-shaped groove 11. As the fiber is withdrawn from roll id it has become a twisted fiber 13.

FIGURE 6 is a cross-sectional view of the twisted multifilament fiber 13 and shows that the fiber is rounded and that there are substantially few interstices between the individual filaments of the fiber.

These fibers are advantageously employed in making a material which will ultimately have seams made in it. If the fiber is punctured with a needle, for example, and relatively few filaments are broken, the fiber still retains the characteristics and properties of the original fiber to a substantial degree.

The fibers prepared according to this invention possess many of the advantages of both the mono-filament and multi-fdament fibers. Although these fibers are strong,

there is little tendency for the individual filaments to separate away from the fiber and get tang ed in the fiber guides of an apparatus used in connection with the fibers.

I claim:

1. The method of wet spinning isocyanate modified dihydroxy elastomeric polymers dissolved in a solvent to produce a multifilament fiber having a substantially round cross-section, which comprises extruding the polymer solution through a plurality of orifices into a liquid coag-.

ulating bath to form a plurality of filaments, gathering together the filaments and applying sufiicient pressure to them, while they are in contact with the coagulating bath liquid and while they are in the state of semi-plastic flow, to consolidate them into a fused multifilament fiber, and subsequently imparting a twisting action to the multifilament fiber while it is in contact with the coagulating bath liquid and While it is in the state of semi-plastic flow.

2. The method of wet spinning isocyanate modified dihydroxy elastomeric polymers dissolved in a solvent to produce a multifilament fiber having a substantially round cross-section, which comprises extruding the polymer solution through a plurality of orifices into a liquid coagulating bath to form a plurality of filaments, gathering together the filaments and applying sufficient pressure to them, while they are in contact with the coagulating bath liquid and while they are in the state of semi-plastic 6 flow, to consolidate them into a fused multifilament fiber, and subsequently imparting a twisting action to the multifilament fiber while it is in contact with the coagulating bath liquid and while it is in the state of semi-plastic flow, said twisting action being accomplished by rolling the multfilament fiber over a smooth surface.

3. An apparatus for treating isocyanate modified dihydroxy filaments formed by coagulating an isocyanate modified dihydroxy elastomeric polymer solution by extrusion into a fluid bath to form a plurality of filaments which comprises means for consolidating a plurality of said filaments into a fused multifilament fiber by imparting pressure to the plurality of filaments while they are still in the state of at least semi-plastic flow and in contact with the bath fluid, and means for imparting a twisting action to said fiber to effect substantially complete consolidation of the filaments making up the fiber and to impart a roundness theerto.

4. The apparatus according to claim 3 in which the means for consolidating a plurality of the filaments into a multifilament is a roller provided with a plurality of V-shaped grooves about its periphery through which the plurality of filaments are led.

5. The apparatus according to claim 4 in which the means for imparting a twisting action to the multifilament fiber is a pair of rollers positioned obliquely to the path of the fiber and containing l-shaped grooves about their periphery, whereby the fiber is passed, within the V- shaped grooves, over one roller and under the other.

6. The apparatus according to claim 5 in which the means for imparting a twisting action to the multifilament fiber is a pair of rollers containing V-shaped grooves about their periphery, said V-shaped grooves being displaced laterally to the path of the fiber so that as the fiber is passed, through the V-shaped grooves, over one roll and under the other, there is provided a twisting action on the fiber.

7. The apparatus according to claim 4 in which the means for imparting a twisting action to said fibers comprises a V-shaped groove lying in a plane which is angularly displaced from a plane of which the multifilament fiber is an element.

References Eited in the file of this patent UNITED STATES PATENTS 2,041,798 Taylor May 26, 1936 2,072,926 Taylor Mar. 9, 1937 2,079,133 Taylor May 4, 1937 2,149,425 Draemann Mar. 7, 1939 2,786,737 Hawtin et a1 Mar. 26, 1957 2,804,645 Wilfong Sept. 3, 1957 2,923,598 Reis et al. Feb. 2, 1960

Claims

1. THE METHOD OF WET SPINNING ISOCYANATE MODIFIED DIHYDROXY ELASTOMERIC POLYMERS DISSOLVED IN A SOLVENT TO PRODUCE A MULTIFILAMENT FIBER HAVING A SUBSTANTIALLY ROUND CROSS-SECTION, WHICH COMPRISES EXTRUDING THE POLYMER SOLUTION THROUGH A PLURALITY OF ORIFICES INTO A LIQUID COAGULATING BATH TO FORM A PLURALITY OF FILAMENTS, GATHERING TOGETHER THE FILAMENTS AND APPLYING SUFFICIENT PRESSURE TO THEM, WHILE THEY ARE IN CONTACT WITH THE COAGULATING BATH LIQUID AND WHILE THEY ARE IN THE STATE OF SEMI-PLASTIC FLOW, TO CONSOLIDATE THEM INTO A FUSED MULTIFILAMENT FIBER, AND SUBSEQUENTLY IMPARTING A TWISTING ACTION TO THE MULTIFILAMENT FIBER WHILE IT IS IN CONTACT WITH THE COAGULATING BATH LIQUID AND WHILE IT IS IN THE STATE OF SEMI-PLASTIC FLOW.