CA1340008C - Process of treating shrinkable fibers - Google Patents
Process of treating shrinkable fibersInfo
- Publication number
- CA1340008C CA1340008C CA000575127A CA575127A CA1340008C CA 1340008 C CA1340008 C CA 1340008C CA 000575127 A CA000575127 A CA 000575127A CA 575127 A CA575127 A CA 575127A CA 1340008 C CA1340008 C CA 1340008C
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- CA
- Canada
- Prior art keywords
- tow
- section
- steam
- fibers
- entrance opening
- 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 - Fee Related
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Classifications
-
- D—TEXTILES; PAPER
- D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
- D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
- D02J13/00—Heating or cooling the yarn, thread, cord, rope, or the like, not specific to any one of the processes provided for in this subclass
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
- D06B3/00—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating
- D06B3/04—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating of yarns, threads or filaments
- D06B3/045—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating of yarns, threads or filaments in a tube or a groove
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- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Treatment Of Fiber Materials (AREA)
- Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
Abstract
A process for diffusing and subliming water-soluble and water-insoluble materials into never-dried, shrinkable aromatic polyamide fibers, using steam heated at certain controlled temperatures, within a specially designed treatment chamber.
Description
Title Pr~cess of Treating Shrinkable Fibers Background of the Invention Field of the Invention The field of art to which this invention pertains is shrinkable materials and, more particularly, it is directed to processes for treating a tow of shrinkable fibers.
Specifically such invention is a process of treating a tow of aromatic polyamide fibers by moving the tow in folds through a chamber having a plug section which is operatively connected by a restricted opening to a treatment section and by heating the tow with steam in the treatment section.
Sufficient steam migrates into the plug section to cause shrinkage of the tow in this section. The cross-sectional area of the tow is substantially the same as the cross-sectional area of the entrance opening of the plug section as it enters such opening but it has a smaller cross-sectional area, due to shrinkage, as it leaves this section and moves through the re-stricted entrance opening of the treatment section. By making this opening smaller so that the cross-sectional area of the shrunken tow as it enters such restricted opening is sub-stantially the same as the cross-sectional area of such opening, loss of steam through the entrance opening of the plug section 15 mlnlmlzed.
More specifically, this invention is a process for dyeing a fiber structure of poly(meta-phenylene isophthalamide) fibers with a water-soluble dye by heating the amorphous, shrink-able fibers, as spun and prior to drying, with steam, in a specifically designed chamber, at a temperature from about 110~C. to about 140~C., and preferably at about 120~C., for a time sufficient to diffuse substantially all of the dye into the minute pores in the fibers, throughout the fiber structure.
An organic water-insoluble material, such as an ultra-violet light screener, may also be mixed with the water-soluble dye and padded onto the water-swollen fibers prior to heating.
*
~"-~ q 1~
While the dye is effectively d;i'~sed into the fiber structure at temperatures between 110~(. and 140~C., 6uch structure must also be heGted with steam at a sublimation temperature be-low the glass transition temperature of the fibers in order to sublime the screener into the pores of the fibers. The fibers are then, preferably, further. heated with steam at about 165~C.
for a time sufficient to collapse the pores in the fibers and lock the dye therein. At thi.s temperature the fibers also will crystalli~e and the fiber struc~ure is thereby stabilized against progressive laundry shrinkage.
Description of the Related Art Aromatic polyamide fibers are well known to the art.
They have high tensile strength, are flame and heat resistant, possess good flex life, and have high melting points which make them particularly suited to be formed into fabrics usable as protective clothing, and for many other uses.
It further is kno~. that while aromatic polyamide fibers possess many desired properties as manufactured they al-so require, for given uses, t.hat various steps be taken to im-prove a property or properties of the fikers to meet a specific end use. As an example, various additives such as dyes, ultra-violet light screeners, flame retardants, antistatic agents or wa.er repellents, may be incorporated into the fibers during basic manufacture or in subse~uent proces,ing steps to improve their performance levels.
This invention is specifically directed to aromatic polyamide fibers of a poly(meta-phenylene isophthalamide) poly-mer, hereinafter referred to as "MPD-I fibers". Such fibers, which are descri_ed in greater detail in U. S. patent 3,287,324 to Sweeny, for example, pos5ess many useful properties. It is well known to the art, however, that these fibers are difficult to dye.
Various techniques have evolved to solve this dyeing problem.
~ r~ 2 Surprisingly it has been found that by heating as-spun, never-dried, water-swollen, or still moist to the touch, MPD-I
fibers with steam, heated withi~ certain temperature ranges, it is possible effect:ively to dye the fibers. Specifically, it has been found that such fibers may be dyed, using a water-soluble dye, by heating the fibers with steam heated at a temperature from about 110~C. to 140~C. for a time suf icient to diffuse the dye into the pores of the fibers.
It further has been found that after this diffusion step has taken place that such fibers may be subsequently heated, again with ste~m, at a temperature of about 165~C. to collapse the fibers and lock the dye in place. This latter step will al-so crystallize the fibers and stabilize them against progressive laundry shrinkage.
In practicing the invention just: described, the treat-ment or dyeing or the fibers is accomplisrled by moving such fibers, in tow form, through a treatment chamber having one or more treatment sections. It has been found difficult to main-tain the steam temperatures at the critical limits required, within these sec'ions, since 1he steam tends to migrate toward the chamber openings. This problem is partially solved by supplying the tow to the chamber in foLds. ~hile this is an effective means of controlling the loss of s'e~m, the problem still remains tro~lesome, particularly in the case of shrinkable tcws because their cross-sections vary due to shrinkage as they move through the ch~mber.
Accorcingly, this invention provides i.~proved proc-esses for treati.g aromatic polyamide fibers, using ste~~ to cye a water-swollen fiber structure of poly(meta-phenylene isoph-thalamide) fibers with a water-solu~le dye, before they are h~ A ~
gi1~3 dried, or to add an organic water-insoluble material to the fibers, either mixed with the dye or alone, and to lock the dye and/or other impregnant into the pores of the fibers. This is accomplished by maintaining the steam wi~hin certain critical temperature ranges (e.g., 110~C. to 140~C.) in a specially de-signed chamber to diffuse the dye into the fiber pores and up to 165~C. to sublime the water-insoluble material into such pores.
At this latter temperature the dye is also locked into the fibers~
while stabilizing such fibers against progressive laundry shrink-age.
Summary of the Invention Briefly described, this invention is a process for treating synthetic fibers including the steps of:
moving a tow of shrinkable fibers in folds through a treatment section having an entrance opening and an exit opening smaller than the entrance opening and heating the tow with steam in the treatment section.
In this process, the tow has a cross-sectional area substantially the same as the cross-sectional area of the en-trance opening as it enters that opening whereby loss of steam through such opening is minimized and a smaller cross-sectional area as it leaves the section, due to shrinkage. This latter area is only slightly smaller, or substantially the same size as, the exit opening whereby loss of steam is minimized through this opening as well.
In a more specific embodiment, this invention is a process of treating a tow of shrinkable fibers which includes the steps of:
moving the tow in folds through a plug section operatively connected by a restricted opening to a treatment sec-tion, with the plug section having an entrance opening larger than the restricted opening of the treatment section, and heating the tow with steam in the treatment sec-tion.
) O ~
Sufficient steam migrates throu~h the restric~ed open-ing from the treatment section to the plug 8ection to ~ u~e shrinkage of the tow in the plug section. The tow has a cross-sectional area substantially the same as the cross-sectional area of the entrance opening of the plug section as it moves through this opening and has a smaller cross-sectional area as it leaves the plug section and moves through the entrance open-ing of the treatment section, due to shrinkage. The cross-sectional area of the shrunken tow as it enters the smaller entrance opening of the treatment section is substantially the same as the cross-sectional area of this opening and, along with the tow moving in folds in the plug section, this sub-stanially prevents loss of steam through the entrance opening of the plug section, Preferably the tow is an amorphous aromatic poly-amide and, more specifically the aromatic polyamide is poly (meta-phenylene isophthalamide). Such tow has a second order glass transition temperature in steam of above about 150~C.
The processes just described further may include the steps of padding a water-soluble dye onto the tow prior to the treatment section and heating the tow with steam in the treat-ment section at a temperature of from about 110~C. to 140~C.
for a time sufficient to diffuse the dye into pores in the fibers of the tow. Still further steps may include moving the tow into a second treatment section and heating the tow with steam in this section at a temperature above its glass temperature from about 150~C. to 165~C, for a time sufficient to collapse the pores and lock the dye within the fibers and to crystallize such fibers and thereby stabilize the tow against progressive laundry shrinkage.
In still another embodiment, the process of this in-vention includes the steps of:
moving the tow through first and second treatment sec-tions, contacting the fibers of the tow prior to the first treatment section with an aqueous mixture containing a water-soluble dye and an organic water-insoluble material which '13~000g sublimes in steam at a temperature below the glass transition temperature of the fibers, heating the water-swollen fibers with steam in the first treatment section at a temperature from about 110~C. to 140~C. for a time sufficient: to diffuse substantially all of the water-soluble dye into the pores of such fibers throughout the fiber structure, heating the water-swollen fibers with steam at a sub-limation temperature below the glass transition temperature of the fibers for a time sufficient to sublime the water-insoluble material into the pores of such fibers throughout the fiber structure, and thereafter heating the water-swollen fibers with steam in the second treatment section at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the dye within the fibers and to stabilize the fibers against progressive laundry shrinkage.
In this latter process, the fibers preferably are heated with steam at a sublimation temperature from about 110~C.
to 150~C. The water-insoluble material may be an ultraviolet light screener and the water-insoluble material may be a dis-perse dye. Further the fibers may be heated with steam in the second treatment section at a temperature of about 165~C. to stabilize the fibers.
In more precise detail, this invention is a process of treating a tow of shrinkable material including the steps of:
moving the tow at a first speed through an entrance opening at one end of a funnel-shaped, fold-forming section hav-ing converging walls which define a discharge opening at the other end of the section, with the entrance opening being larger than the discharge opening;
moving the folded tow through a restricted entrance opening of a chamber defined by walls and having a plurality of sections including a plug section and first and second steam treatment sections, with the chamber being connected to the dis-charge opening of the fold-forming section and the chamber 139 D~08 entrance opening being smaller than the entrance opening of fold-forming section, and the chamber further having a tow exit opening wherein the dual action of the converging walls of the fold-forming section and the tow pushing through the re-stricted entrance opening of the chamber forms a plurality of folds in the tow, wherein steam is introduced into the second steam treatment section, which is positioned between the entrance and exit openings of the chamber, whereby such steam flows, in one direction into and through the second steam treatment section and into t,he first steam treatment section, and from there into the plug section and toward the entrance opening of the fold-forming section and in the other direction into and through the second steam treatment section and toward the exit opening of the cham-ber, engaging the folds of the tow as it is moved in the fold-forming section and through the entrance opening of the chamber with pins on an endless chain moving at a second speed slower than the first speed moving the tow in folds through the plug section at the second speed and wherein the plurality of folds of the tow are in sub-stantial contact with the walls of chamber defining the plug sec-tion during a substantial portion of their movement through this section whereby to help substantially eliminate loss of steam through the entrance opening of the fold-forming section and wherein the steam flowing into this plug section shrinks the tow so that it has a cross-sectional area smaller than that at which it entered this section moving the tow in folds through a restricted entrance opening of the first treatment section, with such entrance open-ing being smaller than the entrance opening of the chamber 1 3400~8 moving the tow through the first treatment section at the second speed and wher,ein the plurality of folds of the tow, as shrunken in the first plug ~section, are substantially in contact with the walls defining the first treatment section through much of their movlement through this section whereby to further help prevent any losls of steam flowing though this sec-tion and through the plug section from escaping through the en-trance opening of the fold-forming section.
In such process, preferably, the chain engages two tows, one on each side, and moves them at the second speed through the chamber and the entrance opening of the chamber is connected to discharge op,ening of the fold-forming section by a tapered surface. A taplered surface also preferably connects the plug section to the entrance opening of the treatment sec-tion.
Finally, in its broadest terms, this invention matches the shrinking profile of the tow with the profile of the chamber walls, during treatment of such tow in the chamber.
Brief Description of the Drawing Fig. 1 is a sch~matic view of an apparatus, including a treatm,nt chamber suita~ble for practicing the process of this invention.
Figs. 2 and ~A are schema~ic:views showing the chamber in greater detail.
Fig. 3 is a cross-sectional view taken along lines A-A of Fig. 1, which highlights a significant feature of this invention, in showing the substantial contact of the tow with the walls defining the restricted opening of the treatment sec-tion of the chamber as it is moved through that opening.
Description of th~e Preferred Embodiments This invention is an improved process for treating shrinkable materials, such as aromatic polyamide fibers.
More Ispecifically,in the processes of this invention, a water-soluble material, and, if desired, a water-insoluble material are diffused or sublimed into a fiber structure of MPD-I amorphous synthetic fibers to improve their properties.
13~0008 During the diffusion and sublimation steps, the fibers are water-swollen or damp to the touch, with open pores. Steam controlled at critical temperatures in a chamber, is used to perfect the process~
Briefly, the fibers of this invention are prepared from aromatic polyamide polymers such as are disclosed in U. S.
patent 3,063,966 to Kwolek, Morgan and Sorenson; 3,094,511 to Hill, Kwolek and Sweeny; and 3,287,324 to Sweeny, for example.
In preparing the basic water-swollen MPD-I fibers which are treated by the procless of this invention, aromatic polyamides which have been prepared by procedures shown in the above-mentioned patents are combined with various solvents to form a spinning solution as shown, for example, in U. S. patent 3,063,966 and the fibers or filaments are formed by extruding the spinning solution through orifices in a spinneret. Such fibers may be dry-spun or wet-spun to form a water-swollen fiber structure. In elther case, the fibers as spun are substantially amorphous.
The fibers whether dry-spun or wet-spun contain a substantial amount of solvent after having been solidified in a dry-spinning e-a~oration cell or coagulated in a wet-spinning precipitation bath. To remove the solvent such fibers are brought into contact with an aqueous extraction bath, as is known in the art~ As a result the fibers become "water-swollen"
with a water content of around 35% or more.
The above-described steps of forming amorphous water-swollen fibers of an aromatic polyamide polymer are known to the art and these fibers are all suitable for being further treated or processed in accordance with the process of this in-vention.
Specifically, in a preferred process, these water-swollen fibers, which have not been dried, are contacted with an aqueous solution c~ntaining a water-soluble material and heated with steam at a temperature from about 110~C. to 140~C.
for a time sufficient to diffuse substantially all of the water-soluble material into the pores of the fibers throughout such fiber structure. The material diffused into the fibers preferably is a dye.
It may also be a surfactant.
In another preferred embodiment, when the material is dyed, the water-swollen, dye-containing fibers are then further heated with steam at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the dye within the fibers and to crystallize such fibers and stabilize them against progressive laundry shrinkage.
Temperatures in the range from 150~C to 165~C will accomplish these objectives.
In still anther embodiment, never-dried, amorphous MPD-I
fibers of the type described are contacted with an aqueous mixture containing both a water-soluble material, such as a dye, and an organic water-insoluble material which sublimes in steam at a temperature below the glass transition temperature of the fibers.
The water-swollen fibers are then heated with steam at a temperature from about 110~C to 140~C for a time sufficient to diffuse substantially all of the water-soluble dye into the pores of such fibers and at a sublimation temperature below the glass transition temperature of the fibers to sublime the water-insoluble material into the open pores of such fibers. After the diffusion an sublimation steps have been completed, the fibers may be further heated with steam at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the material within the fibers and to stabilize the fibers against progressive laundry shrinkage.
The term "fiber", as used herein, includes both staple fibers and continuous filaments. The continuous filaments may be in the form of a tow containing a large number of filaments or in the form of a yarn.
Referring specifically to Figure 1 of the drawing, a fiber structure of never-dried, shrinkable fibers, as spun, in large bundles called tow, as indicated by the reference I
13~0008 numeral 1, is supplied from a ~upply ~ource 2 and passed over guide rolls 3 to nip rolls 4 and 4'.
An aqueous bath 5 of constant level is maintained at the entrance to the nip rolls. The tow 1 of moist to th~ touch fibers is brought into contact with the bath 5 which contains the material (e.g., a water-soluble dye, or surfactant, or ultraviolet light screener, for example) to be diffused or sub-limed into the fibrous tow. The pick-up of material on the never-dried tow may be adjusted by suitably controlling the speed of the tow and the pressure applied between the nip rolls.
The tow 1 coated with the desired amount of material is then moved by feed rolls 6 into a treatment chamber 7, which is suitably an elongated tube having two or more treatment sections to which steam under appropriate pressure can be sup-plied, as will be explained in greater detail.
The tow is heated in these treatment sections at the required critical temperatures to diffuse the water-soluble material and to sublime the insoluble material into the fibers, after which such fibers may be further heated to stabilize the fiber structure against progressive laundry shrinkage.
The processed tow is then moved out of the chamber 7 and onto a conveyor 8, and then through squeeze rolls 9 to help remove water from the treated tow. The tow is then fed by feed rolls 10 into a dryer 11, which includes upper and lower con-veyors 12 and 13 which move the tow at a speed which is adapted to form folds in the tow in the dryer. Such conveyors move the tow through the dryer 11 for a time sufficient to remove sub-stantially all of the water from the tow. The dried and proc-essed tow is then moved over transfer rolls 14 and into a storage container 15.
The treatment process will now be described in detail.
.
The tow 1 carrying the dye or other treatment m~terial from the bath 5 is fed by feed rolls 6 at a first speed through an entrance opening 17 at one end of a funnel-shaped, fold--forming section 18 having converging walls 19 which define a discharge opening 20 at the other end of the section.
134~0~8 The tow is then moved through a restricted entrance opening 21 of the treatme!nt chamber 7 defined by walls 22 and having a plurality of sections including a plug ~ection 23 and first and second steam treatment sections 24 and 25. The chamber 7 is connected, preferably by a sharply tapered surface 22' to the discharge opening 20 of the fold-forming section 18 and the chamber entrance opening 21 is smaller than the en-trance c,pening 17 of the fold-forming section 18. The dual action of the converging walls of the fold-forming section 18 and the tow 1 pushing through the restricted entrance opening 21 of the chamber 7 formci a plurality of folds in the tow. The chamber 7 further has a tow exit opening 26.
Steam in introduced into the second steam treatment section 25 which is posit:ioned between the entrance and exit openings 21, 26 of the chamber 7. The steam flows in one direction into the seconcl steam treatment section 25, then through this section and into the first steam treatment section 24, and from there into t:he plug section 23 and toward the en-trance opening 17 of the fold-forming section 18 and in the other direction into and through the second steam treatment sec-tion 25 and toward the e~cit opening 26 of the chamber 7.
As best seen in Figure 3, the folds of the tow 1 are engaged by pins 27 on an endles~ chain 28 as the tow is moving in fold~-forming section ]L8 and through the entrance opening 21 of the chamber 7. The chain 28 moves at a second speed slower than the first speed at which the tow is fed into the fold-forming section 18, by feed rolls 6.
The tow is moved in folds through the plug section 23 at this second speed. In this section 23 the plurality of folds of the l:ow are in substantial contact with the walls of chamber 7 during a-substantial portion-of-their movement through_such section whereby to help ;ubstantially eliminate loss of steam through the entrance opening 17 of the fold-forming section 18.
The ste~m flowing into this plug section 18 shrinks the tow so-that it has a cross-sectional area smaller than that at which it enteced the section. The tow is then moved from the plug section 23 and a restricted entrance opening 29 of the first treatment section 24. The restricted entrance opening 29 i8 smaller than the restricted entrance opening 21 of the chamber 7.
The tow is moved through the first treatment section 24 at the second speed and the plurality of folds of the tow, as shrunken in the plug section 23, are substantially in con-tact with the walls defining the first treatment section 24 through much of their movement through such section whereby to further help prevent any loss of steam flowing through this sec-tion 24 and through the plug section 23 from e~caping through the entrance opening 17 of the fold-forming section 18. Thi6 inven-tion provides better control of steam temperatures in the criti-cal treatment sections of the chamber.
The substantial contact of the folded tow with the walls of the chamber 7, pushing through the restricted entrance opening 21 of the plug section 23 and hence through the re-stricted opening 29 of the first treatment section 24, along the contact of the folds with the walls 22 in these sections, substantially prevents escape of steam through the entrance opening of the chamber.
In this same connection, it frequently is desirable to wash the treated fibers in a wash section 30 of the chamber 7 prior to discharge of the tow from such chamber. The wash water along with the folded tow, further combine to substantial-ly prevent loss of steam through the exit opening 26 of the cham-ber, as well.
By controlling loss of steam through the chamber open-ings, it is possible to maintain better control of the critical temperatures required in the first and second treatment sec-tions, to effectively treat the fibers, as-previously described.
The treatment of the tow in the manner just de-scribed provides MPD-I fibers having the improved properties sought in the treatment.
The following example will further illustrate this invention .
Examp~e A. Preparation of Never-Dried Filaments of Poly(meta-phenylene isophthalamide) ~MPD-I).
Filaments of MPD-I having an inherent viscosity of 1.5 were dry spun from a filtered solution containing 19%
MPD-I, 70~ dimethylacetamide (DMac), 9% calcium chloride, and 2% water. On leaving the drying tower the as-spun filaments were given a preliminary wash with water so that they contained about 60% DMac, 15% calcium chloride, and 100-150% water, based on the weight of dry polymer. The filaments were washed and drawn 4X at 90~C. in a counter-current extraction-draw process in which the calcium chloride determined as chloride content and DMac content were reduced to about 0.1% and 0.5%, re-spectively. The wet filaments were gathered together to form a tow, a conventional antistatic finish was applied to the tow, and the tow was crimped in a stuffer box crimper at a tempera-ture of about 80~C. in the presence of steam. The tow was then collected, still moist to the touch, in a plastic-lined card-board box. The individual filaments had a linear density of about 1.55 decitex ~dtex) (1.7 dpf). The linear density of the never-dried filaments here and elsewhere herein is based on the weight of dry filaments.
B. Dyeing and Shrinka~e Stabili~ation of Tows of Never-Dried MPD-I Filaments in a Steam Chamber.
Two 120-kilotex (1~000,000 denier) tows of never-dried MPD-I filaments, prepared as described in Part (A) above, were creeled through the guides of a continuous tow dyeing apparatus equipped for high shrinkage tow. The tows were first fed between nip rolls at a rate of 14 m/min. wherein an aqueous dye solution was padded onto the tow so that the individual ~ilaments in the tow were coated with the solution~ The solution contained 40 g/l of C.I. (Colour Index) No.-Basic Yellow 28 dye (a water-soluble dye), and 6 g/l of C.I. No. Basic Red 15 (a water-soluble dye), and 6 g/l cellulosic thickner, and 58 g/l of anionic surfactant, adjusted to a pH of 7 (adding acetic acid or caustic soda as need-ed until the desired pH was obtained). The pick-up of the dye solution on the tow as 30 weight %.
134~ûO~ ' ,~
Af~er t~e ~ow~ were ra~Ae~ with the dye ~olution, they were then passed through the entrance funnel of 4 ch~er, such as that shown in Figure 2, the rectangular discharge end of the funnel having a width of 95 mm and a depth of 115 mm.
Within the funnel the tows were turned and then gathered into fold~ as they were picked up by a chain moving at 1 m/min., one tow on each 6ide of the chain. The tow6, carried by the chain, were then pas6ed into the entrance Gl~ning of a plug section of the ch~her, which had a rectangular cross 6ection 90 mm in width and 110 mm in depth, the discharge op~ing of the funnel and the entrance opening of the plug ~ection being gently tapered into one another to avoid a stair step tr~nsi-tion. The plug ~ection wa~ 3 m in length, and from it the tows were carried by the chain into a first treatment section, al~
Specifically such invention is a process of treating a tow of aromatic polyamide fibers by moving the tow in folds through a chamber having a plug section which is operatively connected by a restricted opening to a treatment section and by heating the tow with steam in the treatment section.
Sufficient steam migrates into the plug section to cause shrinkage of the tow in this section. The cross-sectional area of the tow is substantially the same as the cross-sectional area of the entrance opening of the plug section as it enters such opening but it has a smaller cross-sectional area, due to shrinkage, as it leaves this section and moves through the re-stricted entrance opening of the treatment section. By making this opening smaller so that the cross-sectional area of the shrunken tow as it enters such restricted opening is sub-stantially the same as the cross-sectional area of such opening, loss of steam through the entrance opening of the plug section 15 mlnlmlzed.
More specifically, this invention is a process for dyeing a fiber structure of poly(meta-phenylene isophthalamide) fibers with a water-soluble dye by heating the amorphous, shrink-able fibers, as spun and prior to drying, with steam, in a specifically designed chamber, at a temperature from about 110~C. to about 140~C., and preferably at about 120~C., for a time sufficient to diffuse substantially all of the dye into the minute pores in the fibers, throughout the fiber structure.
An organic water-insoluble material, such as an ultra-violet light screener, may also be mixed with the water-soluble dye and padded onto the water-swollen fibers prior to heating.
*
~"-~ q 1~
While the dye is effectively d;i'~sed into the fiber structure at temperatures between 110~(. and 140~C., 6uch structure must also be heGted with steam at a sublimation temperature be-low the glass transition temperature of the fibers in order to sublime the screener into the pores of the fibers. The fibers are then, preferably, further. heated with steam at about 165~C.
for a time sufficient to collapse the pores in the fibers and lock the dye therein. At thi.s temperature the fibers also will crystalli~e and the fiber struc~ure is thereby stabilized against progressive laundry shrinkage.
Description of the Related Art Aromatic polyamide fibers are well known to the art.
They have high tensile strength, are flame and heat resistant, possess good flex life, and have high melting points which make them particularly suited to be formed into fabrics usable as protective clothing, and for many other uses.
It further is kno~. that while aromatic polyamide fibers possess many desired properties as manufactured they al-so require, for given uses, t.hat various steps be taken to im-prove a property or properties of the fikers to meet a specific end use. As an example, various additives such as dyes, ultra-violet light screeners, flame retardants, antistatic agents or wa.er repellents, may be incorporated into the fibers during basic manufacture or in subse~uent proces,ing steps to improve their performance levels.
This invention is specifically directed to aromatic polyamide fibers of a poly(meta-phenylene isophthalamide) poly-mer, hereinafter referred to as "MPD-I fibers". Such fibers, which are descri_ed in greater detail in U. S. patent 3,287,324 to Sweeny, for example, pos5ess many useful properties. It is well known to the art, however, that these fibers are difficult to dye.
Various techniques have evolved to solve this dyeing problem.
~ r~ 2 Surprisingly it has been found that by heating as-spun, never-dried, water-swollen, or still moist to the touch, MPD-I
fibers with steam, heated withi~ certain temperature ranges, it is possible effect:ively to dye the fibers. Specifically, it has been found that such fibers may be dyed, using a water-soluble dye, by heating the fibers with steam heated at a temperature from about 110~C. to 140~C. for a time suf icient to diffuse the dye into the pores of the fibers.
It further has been found that after this diffusion step has taken place that such fibers may be subsequently heated, again with ste~m, at a temperature of about 165~C. to collapse the fibers and lock the dye in place. This latter step will al-so crystallize the fibers and stabilize them against progressive laundry shrinkage.
In practicing the invention just: described, the treat-ment or dyeing or the fibers is accomplisrled by moving such fibers, in tow form, through a treatment chamber having one or more treatment sections. It has been found difficult to main-tain the steam temperatures at the critical limits required, within these sec'ions, since 1he steam tends to migrate toward the chamber openings. This problem is partially solved by supplying the tow to the chamber in foLds. ~hile this is an effective means of controlling the loss of s'e~m, the problem still remains tro~lesome, particularly in the case of shrinkable tcws because their cross-sections vary due to shrinkage as they move through the ch~mber.
Accorcingly, this invention provides i.~proved proc-esses for treati.g aromatic polyamide fibers, using ste~~ to cye a water-swollen fiber structure of poly(meta-phenylene isoph-thalamide) fibers with a water-solu~le dye, before they are h~ A ~
gi1~3 dried, or to add an organic water-insoluble material to the fibers, either mixed with the dye or alone, and to lock the dye and/or other impregnant into the pores of the fibers. This is accomplished by maintaining the steam wi~hin certain critical temperature ranges (e.g., 110~C. to 140~C.) in a specially de-signed chamber to diffuse the dye into the fiber pores and up to 165~C. to sublime the water-insoluble material into such pores.
At this latter temperature the dye is also locked into the fibers~
while stabilizing such fibers against progressive laundry shrink-age.
Summary of the Invention Briefly described, this invention is a process for treating synthetic fibers including the steps of:
moving a tow of shrinkable fibers in folds through a treatment section having an entrance opening and an exit opening smaller than the entrance opening and heating the tow with steam in the treatment section.
In this process, the tow has a cross-sectional area substantially the same as the cross-sectional area of the en-trance opening as it enters that opening whereby loss of steam through such opening is minimized and a smaller cross-sectional area as it leaves the section, due to shrinkage. This latter area is only slightly smaller, or substantially the same size as, the exit opening whereby loss of steam is minimized through this opening as well.
In a more specific embodiment, this invention is a process of treating a tow of shrinkable fibers which includes the steps of:
moving the tow in folds through a plug section operatively connected by a restricted opening to a treatment sec-tion, with the plug section having an entrance opening larger than the restricted opening of the treatment section, and heating the tow with steam in the treatment sec-tion.
) O ~
Sufficient steam migrates throu~h the restric~ed open-ing from the treatment section to the plug 8ection to ~ u~e shrinkage of the tow in the plug section. The tow has a cross-sectional area substantially the same as the cross-sectional area of the entrance opening of the plug section as it moves through this opening and has a smaller cross-sectional area as it leaves the plug section and moves through the entrance open-ing of the treatment section, due to shrinkage. The cross-sectional area of the shrunken tow as it enters the smaller entrance opening of the treatment section is substantially the same as the cross-sectional area of this opening and, along with the tow moving in folds in the plug section, this sub-stanially prevents loss of steam through the entrance opening of the plug section, Preferably the tow is an amorphous aromatic poly-amide and, more specifically the aromatic polyamide is poly (meta-phenylene isophthalamide). Such tow has a second order glass transition temperature in steam of above about 150~C.
The processes just described further may include the steps of padding a water-soluble dye onto the tow prior to the treatment section and heating the tow with steam in the treat-ment section at a temperature of from about 110~C. to 140~C.
for a time sufficient to diffuse the dye into pores in the fibers of the tow. Still further steps may include moving the tow into a second treatment section and heating the tow with steam in this section at a temperature above its glass temperature from about 150~C. to 165~C, for a time sufficient to collapse the pores and lock the dye within the fibers and to crystallize such fibers and thereby stabilize the tow against progressive laundry shrinkage.
In still another embodiment, the process of this in-vention includes the steps of:
moving the tow through first and second treatment sec-tions, contacting the fibers of the tow prior to the first treatment section with an aqueous mixture containing a water-soluble dye and an organic water-insoluble material which '13~000g sublimes in steam at a temperature below the glass transition temperature of the fibers, heating the water-swollen fibers with steam in the first treatment section at a temperature from about 110~C. to 140~C. for a time sufficient: to diffuse substantially all of the water-soluble dye into the pores of such fibers throughout the fiber structure, heating the water-swollen fibers with steam at a sub-limation temperature below the glass transition temperature of the fibers for a time sufficient to sublime the water-insoluble material into the pores of such fibers throughout the fiber structure, and thereafter heating the water-swollen fibers with steam in the second treatment section at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the dye within the fibers and to stabilize the fibers against progressive laundry shrinkage.
In this latter process, the fibers preferably are heated with steam at a sublimation temperature from about 110~C.
to 150~C. The water-insoluble material may be an ultraviolet light screener and the water-insoluble material may be a dis-perse dye. Further the fibers may be heated with steam in the second treatment section at a temperature of about 165~C. to stabilize the fibers.
In more precise detail, this invention is a process of treating a tow of shrinkable material including the steps of:
moving the tow at a first speed through an entrance opening at one end of a funnel-shaped, fold-forming section hav-ing converging walls which define a discharge opening at the other end of the section, with the entrance opening being larger than the discharge opening;
moving the folded tow through a restricted entrance opening of a chamber defined by walls and having a plurality of sections including a plug section and first and second steam treatment sections, with the chamber being connected to the dis-charge opening of the fold-forming section and the chamber 139 D~08 entrance opening being smaller than the entrance opening of fold-forming section, and the chamber further having a tow exit opening wherein the dual action of the converging walls of the fold-forming section and the tow pushing through the re-stricted entrance opening of the chamber forms a plurality of folds in the tow, wherein steam is introduced into the second steam treatment section, which is positioned between the entrance and exit openings of the chamber, whereby such steam flows, in one direction into and through the second steam treatment section and into t,he first steam treatment section, and from there into the plug section and toward the entrance opening of the fold-forming section and in the other direction into and through the second steam treatment section and toward the exit opening of the cham-ber, engaging the folds of the tow as it is moved in the fold-forming section and through the entrance opening of the chamber with pins on an endless chain moving at a second speed slower than the first speed moving the tow in folds through the plug section at the second speed and wherein the plurality of folds of the tow are in sub-stantial contact with the walls of chamber defining the plug sec-tion during a substantial portion of their movement through this section whereby to help substantially eliminate loss of steam through the entrance opening of the fold-forming section and wherein the steam flowing into this plug section shrinks the tow so that it has a cross-sectional area smaller than that at which it entered this section moving the tow in folds through a restricted entrance opening of the first treatment section, with such entrance open-ing being smaller than the entrance opening of the chamber 1 3400~8 moving the tow through the first treatment section at the second speed and wher,ein the plurality of folds of the tow, as shrunken in the first plug ~section, are substantially in contact with the walls defining the first treatment section through much of their movlement through this section whereby to further help prevent any losls of steam flowing though this sec-tion and through the plug section from escaping through the en-trance opening of the fold-forming section.
In such process, preferably, the chain engages two tows, one on each side, and moves them at the second speed through the chamber and the entrance opening of the chamber is connected to discharge op,ening of the fold-forming section by a tapered surface. A taplered surface also preferably connects the plug section to the entrance opening of the treatment sec-tion.
Finally, in its broadest terms, this invention matches the shrinking profile of the tow with the profile of the chamber walls, during treatment of such tow in the chamber.
Brief Description of the Drawing Fig. 1 is a sch~matic view of an apparatus, including a treatm,nt chamber suita~ble for practicing the process of this invention.
Figs. 2 and ~A are schema~ic:views showing the chamber in greater detail.
Fig. 3 is a cross-sectional view taken along lines A-A of Fig. 1, which highlights a significant feature of this invention, in showing the substantial contact of the tow with the walls defining the restricted opening of the treatment sec-tion of the chamber as it is moved through that opening.
Description of th~e Preferred Embodiments This invention is an improved process for treating shrinkable materials, such as aromatic polyamide fibers.
More Ispecifically,in the processes of this invention, a water-soluble material, and, if desired, a water-insoluble material are diffused or sublimed into a fiber structure of MPD-I amorphous synthetic fibers to improve their properties.
13~0008 During the diffusion and sublimation steps, the fibers are water-swollen or damp to the touch, with open pores. Steam controlled at critical temperatures in a chamber, is used to perfect the process~
Briefly, the fibers of this invention are prepared from aromatic polyamide polymers such as are disclosed in U. S.
patent 3,063,966 to Kwolek, Morgan and Sorenson; 3,094,511 to Hill, Kwolek and Sweeny; and 3,287,324 to Sweeny, for example.
In preparing the basic water-swollen MPD-I fibers which are treated by the procless of this invention, aromatic polyamides which have been prepared by procedures shown in the above-mentioned patents are combined with various solvents to form a spinning solution as shown, for example, in U. S. patent 3,063,966 and the fibers or filaments are formed by extruding the spinning solution through orifices in a spinneret. Such fibers may be dry-spun or wet-spun to form a water-swollen fiber structure. In elther case, the fibers as spun are substantially amorphous.
The fibers whether dry-spun or wet-spun contain a substantial amount of solvent after having been solidified in a dry-spinning e-a~oration cell or coagulated in a wet-spinning precipitation bath. To remove the solvent such fibers are brought into contact with an aqueous extraction bath, as is known in the art~ As a result the fibers become "water-swollen"
with a water content of around 35% or more.
The above-described steps of forming amorphous water-swollen fibers of an aromatic polyamide polymer are known to the art and these fibers are all suitable for being further treated or processed in accordance with the process of this in-vention.
Specifically, in a preferred process, these water-swollen fibers, which have not been dried, are contacted with an aqueous solution c~ntaining a water-soluble material and heated with steam at a temperature from about 110~C. to 140~C.
for a time sufficient to diffuse substantially all of the water-soluble material into the pores of the fibers throughout such fiber structure. The material diffused into the fibers preferably is a dye.
It may also be a surfactant.
In another preferred embodiment, when the material is dyed, the water-swollen, dye-containing fibers are then further heated with steam at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the dye within the fibers and to crystallize such fibers and stabilize them against progressive laundry shrinkage.
Temperatures in the range from 150~C to 165~C will accomplish these objectives.
In still anther embodiment, never-dried, amorphous MPD-I
fibers of the type described are contacted with an aqueous mixture containing both a water-soluble material, such as a dye, and an organic water-insoluble material which sublimes in steam at a temperature below the glass transition temperature of the fibers.
The water-swollen fibers are then heated with steam at a temperature from about 110~C to 140~C for a time sufficient to diffuse substantially all of the water-soluble dye into the pores of such fibers and at a sublimation temperature below the glass transition temperature of the fibers to sublime the water-insoluble material into the open pores of such fibers. After the diffusion an sublimation steps have been completed, the fibers may be further heated with steam at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the material within the fibers and to stabilize the fibers against progressive laundry shrinkage.
The term "fiber", as used herein, includes both staple fibers and continuous filaments. The continuous filaments may be in the form of a tow containing a large number of filaments or in the form of a yarn.
Referring specifically to Figure 1 of the drawing, a fiber structure of never-dried, shrinkable fibers, as spun, in large bundles called tow, as indicated by the reference I
13~0008 numeral 1, is supplied from a ~upply ~ource 2 and passed over guide rolls 3 to nip rolls 4 and 4'.
An aqueous bath 5 of constant level is maintained at the entrance to the nip rolls. The tow 1 of moist to th~ touch fibers is brought into contact with the bath 5 which contains the material (e.g., a water-soluble dye, or surfactant, or ultraviolet light screener, for example) to be diffused or sub-limed into the fibrous tow. The pick-up of material on the never-dried tow may be adjusted by suitably controlling the speed of the tow and the pressure applied between the nip rolls.
The tow 1 coated with the desired amount of material is then moved by feed rolls 6 into a treatment chamber 7, which is suitably an elongated tube having two or more treatment sections to which steam under appropriate pressure can be sup-plied, as will be explained in greater detail.
The tow is heated in these treatment sections at the required critical temperatures to diffuse the water-soluble material and to sublime the insoluble material into the fibers, after which such fibers may be further heated to stabilize the fiber structure against progressive laundry shrinkage.
The processed tow is then moved out of the chamber 7 and onto a conveyor 8, and then through squeeze rolls 9 to help remove water from the treated tow. The tow is then fed by feed rolls 10 into a dryer 11, which includes upper and lower con-veyors 12 and 13 which move the tow at a speed which is adapted to form folds in the tow in the dryer. Such conveyors move the tow through the dryer 11 for a time sufficient to remove sub-stantially all of the water from the tow. The dried and proc-essed tow is then moved over transfer rolls 14 and into a storage container 15.
The treatment process will now be described in detail.
.
The tow 1 carrying the dye or other treatment m~terial from the bath 5 is fed by feed rolls 6 at a first speed through an entrance opening 17 at one end of a funnel-shaped, fold--forming section 18 having converging walls 19 which define a discharge opening 20 at the other end of the section.
134~0~8 The tow is then moved through a restricted entrance opening 21 of the treatme!nt chamber 7 defined by walls 22 and having a plurality of sections including a plug ~ection 23 and first and second steam treatment sections 24 and 25. The chamber 7 is connected, preferably by a sharply tapered surface 22' to the discharge opening 20 of the fold-forming section 18 and the chamber entrance opening 21 is smaller than the en-trance c,pening 17 of the fold-forming section 18. The dual action of the converging walls of the fold-forming section 18 and the tow 1 pushing through the restricted entrance opening 21 of the chamber 7 formci a plurality of folds in the tow. The chamber 7 further has a tow exit opening 26.
Steam in introduced into the second steam treatment section 25 which is posit:ioned between the entrance and exit openings 21, 26 of the chamber 7. The steam flows in one direction into the seconcl steam treatment section 25, then through this section and into the first steam treatment section 24, and from there into t:he plug section 23 and toward the en-trance opening 17 of the fold-forming section 18 and in the other direction into and through the second steam treatment sec-tion 25 and toward the e~cit opening 26 of the chamber 7.
As best seen in Figure 3, the folds of the tow 1 are engaged by pins 27 on an endles~ chain 28 as the tow is moving in fold~-forming section ]L8 and through the entrance opening 21 of the chamber 7. The chain 28 moves at a second speed slower than the first speed at which the tow is fed into the fold-forming section 18, by feed rolls 6.
The tow is moved in folds through the plug section 23 at this second speed. In this section 23 the plurality of folds of the l:ow are in substantial contact with the walls of chamber 7 during a-substantial portion-of-their movement through_such section whereby to help ;ubstantially eliminate loss of steam through the entrance opening 17 of the fold-forming section 18.
The ste~m flowing into this plug section 18 shrinks the tow so-that it has a cross-sectional area smaller than that at which it enteced the section. The tow is then moved from the plug section 23 and a restricted entrance opening 29 of the first treatment section 24. The restricted entrance opening 29 i8 smaller than the restricted entrance opening 21 of the chamber 7.
The tow is moved through the first treatment section 24 at the second speed and the plurality of folds of the tow, as shrunken in the plug section 23, are substantially in con-tact with the walls defining the first treatment section 24 through much of their movement through such section whereby to further help prevent any loss of steam flowing through this sec-tion 24 and through the plug section 23 from e~caping through the entrance opening 17 of the fold-forming section 18. Thi6 inven-tion provides better control of steam temperatures in the criti-cal treatment sections of the chamber.
The substantial contact of the folded tow with the walls of the chamber 7, pushing through the restricted entrance opening 21 of the plug section 23 and hence through the re-stricted opening 29 of the first treatment section 24, along the contact of the folds with the walls 22 in these sections, substantially prevents escape of steam through the entrance opening of the chamber.
In this same connection, it frequently is desirable to wash the treated fibers in a wash section 30 of the chamber 7 prior to discharge of the tow from such chamber. The wash water along with the folded tow, further combine to substantial-ly prevent loss of steam through the exit opening 26 of the cham-ber, as well.
By controlling loss of steam through the chamber open-ings, it is possible to maintain better control of the critical temperatures required in the first and second treatment sec-tions, to effectively treat the fibers, as-previously described.
The treatment of the tow in the manner just de-scribed provides MPD-I fibers having the improved properties sought in the treatment.
The following example will further illustrate this invention .
Examp~e A. Preparation of Never-Dried Filaments of Poly(meta-phenylene isophthalamide) ~MPD-I).
Filaments of MPD-I having an inherent viscosity of 1.5 were dry spun from a filtered solution containing 19%
MPD-I, 70~ dimethylacetamide (DMac), 9% calcium chloride, and 2% water. On leaving the drying tower the as-spun filaments were given a preliminary wash with water so that they contained about 60% DMac, 15% calcium chloride, and 100-150% water, based on the weight of dry polymer. The filaments were washed and drawn 4X at 90~C. in a counter-current extraction-draw process in which the calcium chloride determined as chloride content and DMac content were reduced to about 0.1% and 0.5%, re-spectively. The wet filaments were gathered together to form a tow, a conventional antistatic finish was applied to the tow, and the tow was crimped in a stuffer box crimper at a tempera-ture of about 80~C. in the presence of steam. The tow was then collected, still moist to the touch, in a plastic-lined card-board box. The individual filaments had a linear density of about 1.55 decitex ~dtex) (1.7 dpf). The linear density of the never-dried filaments here and elsewhere herein is based on the weight of dry filaments.
B. Dyeing and Shrinka~e Stabili~ation of Tows of Never-Dried MPD-I Filaments in a Steam Chamber.
Two 120-kilotex (1~000,000 denier) tows of never-dried MPD-I filaments, prepared as described in Part (A) above, were creeled through the guides of a continuous tow dyeing apparatus equipped for high shrinkage tow. The tows were first fed between nip rolls at a rate of 14 m/min. wherein an aqueous dye solution was padded onto the tow so that the individual ~ilaments in the tow were coated with the solution~ The solution contained 40 g/l of C.I. (Colour Index) No.-Basic Yellow 28 dye (a water-soluble dye), and 6 g/l of C.I. No. Basic Red 15 (a water-soluble dye), and 6 g/l cellulosic thickner, and 58 g/l of anionic surfactant, adjusted to a pH of 7 (adding acetic acid or caustic soda as need-ed until the desired pH was obtained). The pick-up of the dye solution on the tow as 30 weight %.
134~ûO~ ' ,~
Af~er t~e ~ow~ were ra~Ae~ with the dye ~olution, they were then passed through the entrance funnel of 4 ch~er, such as that shown in Figure 2, the rectangular discharge end of the funnel having a width of 95 mm and a depth of 115 mm.
Within the funnel the tows were turned and then gathered into fold~ as they were picked up by a chain moving at 1 m/min., one tow on each 6ide of the chain. The tow6, carried by the chain, were then pas6ed into the entrance Gl~ning of a plug section of the ch~her, which had a rectangular cross 6ection 90 mm in width and 110 mm in depth, the discharge op~ing of the funnel and the entrance opening of the plug ~ection being gently tapered into one another to avoid a stair step tr~nsi-tion. The plug ~ection wa~ 3 m in length, and from it the tows were carried by the chain into a first treatment section, al~
3 m in length, which had a rectangular cross section 88 mm in width and 107 mm in depth, the tran~ition from the plug sectiDn to the first treatment section being gently tapered to avoid a stair-step transition. From the first treatment section th~e tows were then carried by the chain into a 6econd treatment section 6 m in length wherein the tows of filaments coated with the 601ution were exposed to steam at a pres~ure of 609 kPa (six bars) and a temperature of 165~C. the ~team being intro-duced into the chamber through holes in thewalls of ~he cham-ber. The ~team flowed from the 6econd steam section bac~ inbo the first treatment section and then lnto the plug sec~tion at progressively lower pressure~ and temperatures in the direction of the entrance funnel, the folds of the tow effectively seal-ing the entrance to the plug section so ~at substantially no steam flowed back into the entrance funnel. W~thin a zone begi~ning at about the end of the plug section and exten~g well into ~he first treatment section the fila~ent~ in the tows coated with the solution were eYroseA to ~team at a t~mperatyre of about 120~C. for a contact time of about two minutes. The temperatur- of the tow- at the end of the first treatment ~eo-tion, going into the ~_o~.d 6team treatment ~ectlon, was abo~t 1 3 4 ~ J 3 3 ,~
165-C. and remained ~t about 165~C. throughout the second treat-ment section. Upon leaving the treatment s-ctions the tows were passed into a final wash section, wherein they were was~hed with water. The water and the wet tows acted together to con-dense the 6team flowing from the second treatment section and formed an ef~ective seal to prevent any steam from flowing from the eXit end of the chamber.
After the tows were washed, they were fed into a f~rced air dryer, wherein their moisture level was reduced to 7%
moisture. Finish was not added to the tow. me tows were d~ed to a bright ~hsde of orange. The shrinkage of the tows was mea~ured and determined to be 0.9~.
In other experiments with similar tows using apparatus having a steam ch~mher of constant area, it was found to be dif~icult to maintain the steam at a pressure higher than ab4ut 203 kPa (t~o bars). The shrinkage of the tow when heated with steam at a pressure of only 203 kPa was 7%.
165-C. and remained ~t about 165~C. throughout the second treat-ment section. Upon leaving the treatment s-ctions the tows were passed into a final wash section, wherein they were was~hed with water. The water and the wet tows acted together to con-dense the 6team flowing from the second treatment section and formed an ef~ective seal to prevent any steam from flowing from the eXit end of the chamber.
After the tows were washed, they were fed into a f~rced air dryer, wherein their moisture level was reduced to 7%
moisture. Finish was not added to the tow. me tows were d~ed to a bright ~hsde of orange. The shrinkage of the tows was mea~ured and determined to be 0.9~.
In other experiments with similar tows using apparatus having a steam ch~mher of constant area, it was found to be dif~icult to maintain the steam at a pressure higher than ab4ut 203 kPa (t~o bars). The shrinkage of the tow when heated with steam at a pressure of only 203 kPa was 7%.
Claims (15)
1. A process of treating a tow of shrinkable fibers including the steps of:
moving the tow in folds through a plug section operatively connected by a restricted opening to a treatment section, said plug section having an entrance opening larger than the restricted opening of the treatment section, and heating the tow with steam in the treatment section wherein sufficient steam migrates through the restricted opening from the treatment section to the plug section to cause shrinkage of the tow in the plug section, and wherein the tow has a cross-sectional area substantially the same as the cross-sectional area of the entrance opening of the plug section as it moves through said opening and wherein the tow has a smaller cross-sectional area as it leaves the plug section and moves through the entrance opening of the treatment section, due to shrinkage, and wherein the cross-sectional area of the shrunken tow as it enters the smaller entrance opening of the treatment section is substantially the same as the cross-sectional area of this opening and wherein the tow moving in folds in the plug section substantially prevents loss of steam through the entrance opening of the plug section.
moving the tow in folds through a plug section operatively connected by a restricted opening to a treatment section, said plug section having an entrance opening larger than the restricted opening of the treatment section, and heating the tow with steam in the treatment section wherein sufficient steam migrates through the restricted opening from the treatment section to the plug section to cause shrinkage of the tow in the plug section, and wherein the tow has a cross-sectional area substantially the same as the cross-sectional area of the entrance opening of the plug section as it moves through said opening and wherein the tow has a smaller cross-sectional area as it leaves the plug section and moves through the entrance opening of the treatment section, due to shrinkage, and wherein the cross-sectional area of the shrunken tow as it enters the smaller entrance opening of the treatment section is substantially the same as the cross-sectional area of this opening and wherein the tow moving in folds in the plug section substantially prevents loss of steam through the entrance opening of the plug section.
2. The process of claim 1 wherein the tow is an amorphous aromatic polyamide.
3. The process of claim 2 wherein the aromatic polyamide is poly(meta-phenylene isophthalamide).
4. The process of claim 2 wherein the aromatic polyamide has a second order glass transition temperature in steam of above about 150°C.
5. The process of claim 2 including the further step of:
padding a water-soluble dye onto the tow prior to the treatment section and wherein the tow is heated with steam in such treatment section at a temperature of from about 110°C to 140°C for a time sufficient to diffuse the dye into pores in the fibers of the tow.
padding a water-soluble dye onto the tow prior to the treatment section and wherein the tow is heated with steam in such treatment section at a temperature of from about 110°C to 140°C for a time sufficient to diffuse the dye into pores in the fibers of the tow.
6. The process of claim 5 including the further step of:
moving the tow into a second treatment section wherein such tow is heated with steam at a temperature above its glass temperature from about 150°C to 165°C for a time sufficient to collapse the pores and lock the dye within the fibers and to crystallize such fibers and thereby stabilize the tow against progressive laundry shrinkage.
moving the tow into a second treatment section wherein such tow is heated with steam at a temperature above its glass temperature from about 150°C to 165°C for a time sufficient to collapse the pores and lock the dye within the fibers and to crystallize such fibers and thereby stabilize the tow against progressive laundry shrinkage.
7. The process of claim 2 including the further steps of:
contacting the fibers of the tow prior to the first treatment section with an aqueous mixture containing a water-soluble dye and an organic water-insoluble material such as a water insoluble dye or ultraviolet light screener which sublimes in steam at a temperature below the glass transition temperature of the fibers, heating the fibers with steam in the first treatment section at a temperature from about 110°C to 140°C for a time sufficient to diffuse substantially all of the water-soluble dye into the pores of such fibers throughout the fiber structure, heating the water-swollen fibers with steam at a sublimation temperature below the glass transition temperature of the fibers for a time sufficient to sublime the water-insoluble material into the pores of such fibers throughout the fiber structure, and thereafter heating the water-swollen fibers with steam in the second treatment section at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the dye within the fibers and to stabilize the fibers against progressive laundry shrinkage.
contacting the fibers of the tow prior to the first treatment section with an aqueous mixture containing a water-soluble dye and an organic water-insoluble material such as a water insoluble dye or ultraviolet light screener which sublimes in steam at a temperature below the glass transition temperature of the fibers, heating the fibers with steam in the first treatment section at a temperature from about 110°C to 140°C for a time sufficient to diffuse substantially all of the water-soluble dye into the pores of such fibers throughout the fiber structure, heating the water-swollen fibers with steam at a sublimation temperature below the glass transition temperature of the fibers for a time sufficient to sublime the water-insoluble material into the pores of such fibers throughout the fiber structure, and thereafter heating the water-swollen fibers with steam in the second treatment section at a temperature above the glass transition temperature of the fibers for a time sufficient to collapse the pores and irreversibly lock the dye within the fibers and to stabilize the fibers against progressive laundry shrinkage.
8. The process of claim 7 wherein the fibers are heated with steam in the first treatment section at a sublimation temperature of from about 110°C to 150°C.
9. The process of claim 7 wherein the water-insoluble material is an ultraviolet light screener.
10. The process of claim 7 wherein the water-insoluble material is a disperse dye.
11. The process of claim 7 wherein the fibers are heated with steam in the second treatment section at a temperature of about 165°C.
12. A process of treating a tow of shrinkable material including the steps of:
moving the tow at a first speed through an entrance opening at one end of a funnel-shaped, fold-forming section having converging walls which define a discharge opening at the other end of the section, said entrance opening being larger than the discharge opening;
moving the folded tow through a restricted entrance opening of a chamber defined by walls and having a plurality of sections including a plug section and first and second steam treatment sections, said chamber being connected to the discharge opening of the fold-forming section and said chamber entrance opening being smaller than the entrance opening of the fold-forming section, said chamber further having a tow exit opening wherein the dual action of the converging walls of the fold-forming section and the tow pushing through said restricted entrance opening of the chamber forms a plurality of folds in the tow, wherein steam is introduced into the second steam treatment section, which is positioned between the entrance and exit openings of the chamber, whereby such steam flows, in one direction into the second steam treatment section, then through this section and into the first steam treatment section, and from there into the plug section and toward the entrance opening of the fold-forming section and in the other direction into and through the second steam treatment section and toward the exit opening of the chamber, engaging the folds of the tow as it is moved in the fold-forming section and through the entrance opening of the chamber with pins on an endless chain moving at a second speed slower than the first speed moving the tow in folds through the plug section at said second speed and wherein the plurality of folds of the tow are in substantial contact with the walls of chamber defining the plug section during a substantial portion of their movement through this section whereby to help substantially eliminate loss of steam through the entrance opening of the fold-forming section and wherein the steam flowing into this plug section shrinks the tow so that it has a cross-sectional area smaller than that at which it entered this section moving the tow in folds through a restricted entrance opening of the first treatment section, said entrance opening being smaller than the restricted entrance opening of the chamber moving the tow through the first treatment section at said second speed and wherein the plurality of folds of the tow, as shrunken in the plug section, are substantially in contact with the walls defining the first treatment section through much of their movement through this section whereby to further help prevent any loss of steam flowing through this section and through the plug section from escaping through the entrance opening of the fold-forming section.
moving the tow at a first speed through an entrance opening at one end of a funnel-shaped, fold-forming section having converging walls which define a discharge opening at the other end of the section, said entrance opening being larger than the discharge opening;
moving the folded tow through a restricted entrance opening of a chamber defined by walls and having a plurality of sections including a plug section and first and second steam treatment sections, said chamber being connected to the discharge opening of the fold-forming section and said chamber entrance opening being smaller than the entrance opening of the fold-forming section, said chamber further having a tow exit opening wherein the dual action of the converging walls of the fold-forming section and the tow pushing through said restricted entrance opening of the chamber forms a plurality of folds in the tow, wherein steam is introduced into the second steam treatment section, which is positioned between the entrance and exit openings of the chamber, whereby such steam flows, in one direction into the second steam treatment section, then through this section and into the first steam treatment section, and from there into the plug section and toward the entrance opening of the fold-forming section and in the other direction into and through the second steam treatment section and toward the exit opening of the chamber, engaging the folds of the tow as it is moved in the fold-forming section and through the entrance opening of the chamber with pins on an endless chain moving at a second speed slower than the first speed moving the tow in folds through the plug section at said second speed and wherein the plurality of folds of the tow are in substantial contact with the walls of chamber defining the plug section during a substantial portion of their movement through this section whereby to help substantially eliminate loss of steam through the entrance opening of the fold-forming section and wherein the steam flowing into this plug section shrinks the tow so that it has a cross-sectional area smaller than that at which it entered this section moving the tow in folds through a restricted entrance opening of the first treatment section, said entrance opening being smaller than the restricted entrance opening of the chamber moving the tow through the first treatment section at said second speed and wherein the plurality of folds of the tow, as shrunken in the plug section, are substantially in contact with the walls defining the first treatment section through much of their movement through this section whereby to further help prevent any loss of steam flowing through this section and through the plug section from escaping through the entrance opening of the fold-forming section.
13. The process of claim 12 in which the chain engages two tows, one on each side, and moves them at said second speed through the chamber.
14. The process of claim 12 in which the restricted entrance opening of the chamber is connected to discharge opening of the fold-forming section by a tapered surface.
15. The process of claim 12 in which the restricted entrance opening of the first treatment section is connected to the plug section by a tapered surface.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000575127A CA1340008C (en) | 1988-08-18 | 1988-08-18 | Process of treating shrinkable fibers |
| ES88307697T ES2045133T3 (en) | 1988-08-18 | 1988-08-19 | PROCEDURE TO TREAT CONTRACTABLE FIBERS. |
| EP88307697A EP0355222B1 (en) | 1988-08-18 | 1988-08-19 | Process of treating shrinkable fibers |
| DE88307697T DE3885277T2 (en) | 1988-08-18 | 1988-08-19 | Process for treating shrinkable fibers. |
| JP63212632A JP2645485B2 (en) | 1988-08-18 | 1988-08-29 | How to treat shrinkable fibers |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000575127A CA1340008C (en) | 1988-08-18 | 1988-08-18 | Process of treating shrinkable fibers |
| EP88307697A EP0355222B1 (en) | 1988-08-18 | 1988-08-19 | Process of treating shrinkable fibers |
| JP63212632A JP2645485B2 (en) | 1988-08-18 | 1988-08-29 | How to treat shrinkable fibers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1340008C true CA1340008C (en) | 1998-08-25 |
Family
ID=27168021
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000575127A Expired - Fee Related CA1340008C (en) | 1988-08-18 | 1988-08-18 | Process of treating shrinkable fibers |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0355222B1 (en) |
| JP (1) | JP2645485B2 (en) |
| CA (1) | CA1340008C (en) |
| DE (1) | DE3885277T2 (en) |
| ES (1) | ES2045133T3 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5306312A (en) * | 1990-10-31 | 1994-04-26 | Burlington Industries, Inc. | Dye diffusion promoting agents for aramids |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1193725A (en) * | 1967-08-12 | 1970-06-03 | Ilma Ind Lavorazioni Matalli A | Process and Apparatus for Continuously Steaming Textile Fibre Material |
| CA1282213C (en) * | 1985-12-16 | 1991-04-02 | E. I. Du Pont De Nemours And Company | Aromatic polyamide fibers and processes for making such fibers |
-
1988
- 1988-08-18 CA CA000575127A patent/CA1340008C/en not_active Expired - Fee Related
- 1988-08-19 DE DE88307697T patent/DE3885277T2/en not_active Expired - Lifetime
- 1988-08-19 ES ES88307697T patent/ES2045133T3/en not_active Expired - Lifetime
- 1988-08-19 EP EP88307697A patent/EP0355222B1/en not_active Expired - Lifetime
- 1988-08-29 JP JP63212632A patent/JP2645485B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0268351A (en) | 1990-03-07 |
| DE3885277T2 (en) | 1994-05-05 |
| DE3885277D1 (en) | 1993-12-02 |
| JP2645485B2 (en) | 1997-08-25 |
| EP0355222B1 (en) | 1993-10-27 |
| ES2045133T3 (en) | 1994-01-16 |
| EP0355222A1 (en) | 1990-02-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |